U.S. flag

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

  • Publications
  • Account settings
  • My Bibliography
  • Collections
  • Citation manager

Save citation to file

Email citation, add to collections.

  • Create a new collection
  • Add to an existing collection

Add to My Bibliography

Your saved search, create a file for external citation management software, your rss feed.

  • Search in PubMed
  • Search in NLM Catalog
  • Add to Search

Nanoparticle therapeutics: an emerging treatment modality for cancer

Affiliation.

  • 1 Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA. [email protected]
  • PMID: 18758474
  • DOI: 10.1038/nrd2614

Nanoparticles--particles in the size range 1-100 nm--are emerging as a class of therapeutics for cancer. Early clinical results suggest that nanoparticle therapeutics can show enhanced efficacy, while simultaneously reducing side effects, owing to properties such as more targeted localization in tumours and active cellular uptake. Here, we highlight the features of nanoparticle therapeutics that distinguish them from previous anticancer therapies, and describe how these features provide the potential for therapeutic effects that are not achievable with other modalities. While large numbers of preclinical studies have been published, the emphasis here is placed on preclinical and clinical studies that are likely to affect clinical investigations and their implications for advancing the treatment of patients with cancer.

PubMed Disclaimer

Similar articles

  • Active targeting schemes for nanoparticle systems in cancer therapeutics. Byrne JD, Betancourt T, Brannon-Peppas L. Byrne JD, et al. Adv Drug Deliv Rev. 2008 Dec 14;60(15):1615-26. doi: 10.1016/j.addr.2008.08.005. Epub 2008 Sep 20. Adv Drug Deliv Rev. 2008. PMID: 18840489 Review.
  • Nanoparticle technologies for cancer therapy. Alexis F, Pridgen EM, Langer R, Farokhzad OC. Alexis F, et al. Handb Exp Pharmacol. 2010;(197):55-86. doi: 10.1007/978-3-642-00477-3_2. Handb Exp Pharmacol. 2010. PMID: 20217526 Review.
  • Nanoparticle and targeted systems for cancer therapy. Brannon-Peppas L, Blanchette JO. Brannon-Peppas L, et al. Adv Drug Deliv Rev. 2004 Sep 22;56(11):1649-59. doi: 10.1016/j.addr.2004.02.014. Adv Drug Deliv Rev. 2004. PMID: 15350294 Review.
  • The potential of liposomes with carbonic anhydrase IX to deliver anticancer ingredients to cancer cells in vivo. Ng HL, Lu A, Lin G, Qin L, Yang Z. Ng HL, et al. Int J Mol Sci. 2014 Dec 24;16(1):230-55. doi: 10.3390/ijms16010230. Int J Mol Sci. 2014. PMID: 25547490 Free PMC article. Review.
  • Composite nanoparticles take aim at cancer. Gil PR, Parak WJ. Gil PR, et al. ACS Nano. 2008 Nov 25;2(11):2200-5. doi: 10.1021/nn800716j. ACS Nano. 2008. PMID: 19206383 Review.
  • Lipid nanoparticle-based mRNA vaccines: a new frontier in precision oncology. Jacob EM, Huang J, Chen M. Jacob EM, et al. Precis Clin Med. 2024 Aug 1;7(3):pbae017. doi: 10.1093/pcmedi/pbae017. eCollection 2024 Sep. Precis Clin Med. 2024. PMID: 39171210 Free PMC article. Review.
  • A structured biomimetic nanoparticle as inflammatory factor sponge and autophagy-regulatory agent against intervertebral disc degeneration and discogenic pain. Li K, Yang W, Chen X, Yu Y, Liu Y, Ni F, Xiao Y, Qing X, Liu S, He Y, Wang B, Xu L, Shao Z, Zhao L, Peng Y, Lin H. Li K, et al. J Nanobiotechnology. 2024 Aug 14;22(1):486. doi: 10.1186/s12951-024-02715-x. J Nanobiotechnology. 2024. PMID: 39143545 Free PMC article.
  • Surface functionalized nanomaterial systems for targeted therapy of endocrine related tumors: a review of recent advancements. Liu L, Yang M, Chen Z. Liu L, et al. Drug Deliv. 2024 Dec;31(1):2390022. doi: 10.1080/10717544.2024.2390022. Epub 2024 Aug 13. Drug Deliv. 2024. PMID: 39138394 Free PMC article. Review.
  • Targeting Wnt-β-Catenin Signaling Pathway for Hepatocellular Carcinoma Nanomedicine. Bakrania A, To J, Zheng G, Bhat M. Bakrania A, et al. Gastro Hep Adv. 2023 Jul 20;2(7):948-963. doi: 10.1016/j.gastha.2023.07.012. eCollection 2023. Gastro Hep Adv. 2023. PMID: 39130774 Free PMC article. Review.
  • Dimeric Drug Polymeric Micelles with Acid-Active Tumor Targeting and FRET-indicated Drug Release. Guo X, Wang L, Duval K, Fan J, Zhou S, Chen Z. Guo X, et al. ArXiv [Preprint]. 2024 Jul 30:arXiv:2407.20538v1. ArXiv. 2024. PMID: 39130205 Free PMC article. Preprint.

Publication types

  • Search in MeSH

Grants and funding

  • U54 CA119338/CA/NCI NIH HHS/United States

LinkOut - more resources

Full text sources.

  • Nature Publishing Group

Other Literature Sources

  • The Lens - Patent Citations

full text provider logo

  • Citation Manager

NCBI Literature Resources

MeSH PMC Bookshelf Disclaimer

The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). Unauthorized use of these marks is strictly prohibited.

  • Open access
  • Published: 07 June 2022

Nanoparticle classification, physicochemical properties, characterization, and applications: a comprehensive review for biologists

  • Nadeem Joudeh 1 &
  • Dirk Linke 1  

Journal of Nanobiotechnology volume  20 , Article number:  262 ( 2022 ) Cite this article

96k Accesses

409 Citations

4 Altmetric

Metrics details

Interest in nanomaterials and especially nanoparticles has exploded in the past decades primarily due to their novel or enhanced physical and chemical properties compared to bulk material. These extraordinary properties have created a multitude of innovative applications in the fields of medicine and pharma, electronics, agriculture, chemical catalysis, food industry, and many others. More recently, nanoparticles are also being synthesized ‘biologically’ through the use of plant- or microorganism-mediated processes, as an environmentally friendly alternative to the expensive, energy-intensive, and potentially toxic physical and chemical synthesis methods. This transdisciplinary approach to nanoparticle synthesis requires that biologists and biotechnologists understand and learn to use the complex methodology needed to properly characterize these processes. This review targets a bio-oriented audience and summarizes the physico–chemical properties of nanoparticles, and methods used for their characterization. It highlights why nanomaterials are different compared to micro- or bulk materials. We try to provide a comprehensive overview of the different classes of nanoparticles and their novel or enhanced physicochemical properties including mechanical, thermal, magnetic, electronic, optical, and catalytic properties. A comprehensive list of the common methods and techniques used for the characterization and analysis of these properties is presented together with a large list of examples for biogenic nanoparticles that have been previously synthesized and characterized, including their application in the fields of medicine, electronics, agriculture, and food production. We hope that this makes the many different methods more accessible to the readers, and to help with identifying the proper methodology for any given nanoscience problem.

Nano etymology

The prefix nano is derived from the Greek word nanos, “a dwarf”. In 1947, at the 14th conference of the International Union of Pure and Applied Chemistry (IUPAC), the prefix nano was officially adopted to describe the one-billionth part (10 –9 ) of a unit Footnote 1 . In scientific literature, the prefix nano has been adopted as a popular label in many fields of modern science to describe small entities and processes. These terms include, but are not limited to nanoscience, nanotechnology, nanorobots, nanomagnets, nanoelectronics, nanoencapsulation, etc. [ 1 ]. In all of these cases, the prefix nano is used to describe “very small” entities or processes, most often at actual nanometer scale.

Definitions

Nanoscience is a branch of science that comprises the study of properties of matter at the nanoscale, and particularly focuses on the unique, size-dependent properties of solid-state materials [ 2 ]. Nanotechnology is the branch that comprises the synthesis, engineering, and utilization of materials whose size ranges from 1 to 100 nm, known as nanomaterials [ 3 ]. The birth of nanoscience and nanotechnology concepts is usually linked to the famous lecture of Nobel laureate Richard Feynman at the 1959 meeting of the American Physical Society, ‘‘There’s Plenty of Room at the Bottom’’ [ 4 ]. However, the use of nanotechnology and nanomaterials goes back in history long before that.

History of nanotechnology

Long before the era of nanotechnology, people were unknowingly coming across various nanosized objects and using nano-level processes. In ancient Egypt, dyeing hair in black was common and was for a long time believed to be based on plant products such as henna [ 5 ]. However, recent research on hair samples from ancient Egyptian burial sites showed that hair was dyed with paste from lime, lead oxide, and water [ 6 ]. In this dyeing process, galenite (lead sulfide, PbS) nanoparticles are formed. The ancient Egyptians were able to make the dyeing paste react with sulfur (part of hair keratin) and produce small PbS nanoparticles which provided even and steady dyeing.

Probably the most famous example for the ancient use of nanotechnology is the Lycurgus Cup (fourth century CE). This ancient roman cup possesses unusual optical properties; it changes its color based on the location of the light source. In natural light, the cup is green, but when it is illuminated from within (with a candle), it becomes red. The recent analysis of this cup showed that it contains 50–100 nm Au and Ag nanoparticles [ 7 ], which are responsible for the unusual coloring of the cup through the effects of plasmon excitation of electrons [ 8 ]. The ancient use of nanotechnology does not stop here, in fact, there is evidence for the early use of nanotechnology processes in Mesopotamia, Ancient India, and the Maya [ 9 , 10 ].

Why nanomaterials are different

Today, due to their unique properties, nanomaterials are used in a wide range of applications, such as catalysis, water treatment, energy storage, medicine, agriculture, etc . [ 11 , 12 , 13 ]. Two main factors cause nanomaterials to behave significantly differently than the same materials at larger dimensions: surface effects and quantum effects [ 14 ]. These factors make nanomaterials exhibit enhanced or novel mechanical, thermal, magnetic, electronic, optical, and catalytic properties [ 1 , 15 , 16 ].

Nanomaterials have different surface effects compared to micromaterials or bulk materials, mainly due to three reasons; (a) dispersed nanomaterials have a very large surface area and high particle number per mass unit, (b) the fraction of atoms at the surface in nanomaterials is increased, and (c) the atoms situated at the surface in nanomaterials have fewer direct neighbors [ 1 , 14 ]. As a consequence of each of these differences, the chemical and physical properties of nanomaterials change compared to their larger-dimension counterparts. For instance, having fewer direct neighbor atoms for the atoms situated at the surface results in lowering the binding energy per atom for nanomaterials. This change directly affects the melting temperature of nanomaterials following the Gibbs–Thomson equation, e.g., the melting point of 2.5 nm gold nanoparticles is 407 degrees lower than the melting point of bulk gold [ 14 ]. Larger surface areas and larger surface-to-volume ratios generally increases the reactivity of nanomaterials due to the larger reaction surface [ 1 ], as well as resulting in significant effects of surface properties on their structure [ 17 ]. The dispersity of nanomaterials is a key factor for the surface effects. The strong attractive interactions between particles can result in the agglomeration and aggregation of nanomaterials, which negatively affects their surface area and their nanoscale properties [ 18 ]. Agglomeration can be prevented by increasing the zeta potential of nanomaterials (increasing the repulsive force) [ 19 ], optimizing the degree of hydrophilicity/hydrophobicity of the nanomaterial, or by optimizing the pH and the ionic strength of the suspension medium [ 20 ].

Nanomaterials display distinct size-dependent properties in the 1–100 nm range where quantum phenomena are involved. When the material radius approaches the asymptotic exciton Bohr radius (the separation distance between the electron and hole), the influence of quantum confinement becomes apparent [ 17 ]. In other words, by shrinking the size of the material, quantum effects become more pronounced, and nanomaterials become quantal. Those quantum structures are physical structures where all the charge carriers (electrons and holes) are confined within the physical dimensions [ 21 ]. As a result of quantum confinement effects, for instance, some non-magnetic materials in bulk such as palladium, platinum, and gold become magnetic in the nanoscale [ 14 ]. Quantum confinement can also result in significant changes in electron affinity or the ability to accept or donate electrical charges, which is directly reflected on the catalytic properties of the material. For example, the catalytic activity of cationic platinum clusters in N 2 O decomposition is dictated by the number of atoms in the cluster. 6–9, 11, 12, 15, and 20 atom-containing clusters are very reactive, while clusters with 10, 13, 14, and 19 atoms have low reactivity [ 14 ].

Classification of nanomaterials

The key elements of nanotechnology are the nanomaterials. Nanomaterials are defined as materials where at least one of their dimensions is in the nanoscale, i.e. smaller than 100 nm [ 22 ]. Based on their dimensionalities, nanomaterials are placed into four different classes, summarized in Fig.  1 .

Zero-dimensional nanomaterials (0-D): the nanomaterials in this class have all their three dimensions in the nanoscale range. Examples are quantum dots, fullerenes, and nanoparticles.

One-dimensional nanomaterials (1-D): the nanomaterials in this class have one dimension outside the nanoscale. Examples are nanotubes, nanofibers, nanorods, nanowires, and nanohorns.

Two-dimensional nanomaterials (2-D): the nanomaterials in this class have two dimensions outside the nanoscale. Examples are nanosheets, nanofilms, and nanolayers.

Three-dimensional nanomaterials (3-D) or bulk nanomaterials: in this class the materials are not confined to the nanoscale in any dimension. This class contains bulk powders, dispersions of nanoparticles, arrays of nanowires and nanotubes, etc .

figure 1

Nanomaterials classification based on dimensionality

Nanoparticles (NPs)

The International Organization for Standardization (ISO) defines nanoparticles as nano-objects with all external dimensions in the nanoscale, where the lengths of the longest and the shortest axes of the nano-object do not differ significantly. If the dimensions differ significantly (typically by more than three times), terms such as nanofibers or nanoplates maybe preferred to the term NPs Footnote 2 .

NPs can be of different shapes, sizes, and structures. They can be spherical, cylindrical, conical, tubular, hollow core, spiral, etc., or irregular [ 23 ]. The size of NPs can be anywhere from 1 to 100 nm. If the size of NPs gets lower than 1 nm, the term atom clusters is usually preferred. NPs can be crystalline with single or multi-crystal solids, or amorphous. NPs can be either loose or agglomerated [ 24 ].

NPs can be uniform, or can be composed of several layers. In the latter case, the layers often are: (a) The surface layer, which usually consists of a variety of small molecules, metal ions, surfactants, or polymers. (b) The shell layer, which is made of a chemically different material from the core layer. (c) The core layer, which is the central portion of the NP [ 25 ].

Classification of NPs

Based on their composition, NPs are generally placed into three classes: organic, carbon-based, and inorganic [ 23 ].

Organic NPs

This class comprises NPs that are made of proteins, carbohydrates, lipids, polymers, or any other organic compounds [ 26 ]. The most prominent examples of this class are dendrimers, liposomes, micelles, and protein complexes such as ferritin (shown in Fig.  2 ). These NPs are typically non-toxic, bio-degradable, and can in some cases, e.g., for liposomes, have a hollow core. Organic NPs are sensitive to thermal and electromagnetic radiation such as heat and light [ 23 ]. In addition, they are often formed by non-covalent intermolecular interactions, which makes them more labile in nature and offers a route for clearance from the body [ 27 ]. There are different parameters that determine the potential field of application of organic NPs, e.g., composition, surface morphology, stability, carrying capacity, etc . Today, organic NPs are mostly used in the biomedical field in targeted drug delivery [ 23 ] and cancer therapy [ 28 ].

figure 2

Types of organic NPs. A Dendrimers; B liposomes; C micelles; and D ferritin

Carbon-based NPs

This class comprises NPs that are made solely from carbon atoms [ 23 ]. Famous examples of this class are fullerenes, carbon black NPs, and carbon quantum dots (shown in Fig.  3 ). Fullerenes are carbon molecules that are characterized by a symmetrical closed-cage structure. C 60 fullerenes consist of 60 carbon atoms arranged in the shape of a soccer ball [ 29 ], but also other types of fullerenes such as C 70 and C 540 fullerenes have been described [ 30 ]. Carbon black NPs are grape-like aggregates of highly fused spherical particles [ 31 ]. Carbon quantum dots consist of discrete, quasi-spherical carbon NPs with sizes below 10 nm [ 32 ]. Carbon-based NPs unite the distinctive properties of sp 2 -hybridized carbon bonds with the unusual physicochemical properties at the nanoscale. Due to their unique electrical conductivity, high strength, electron affinity, optical, thermal, and sorption properties [ 25 , 33 ], carbon-based NPs are used in a wide range of application such as drug delivery [ 34 ], energy storage [ 35 ], bioimaging [ 36 ], photovoltaic devices, and environmental sensing applications to monitor microbial ecology or to detect microbial pathogens [ 33 ]. Nanodiamonds and carbon nano onions are more complex, carbon-based NPs. Due to their characteristic low toxicity and biocompatibility, they are used in drug delivery and tissue engineering applications [ 37 , 38 ].

figure 3

Different types of carbon-based NPs. A C 60 fullerene; B carbon black NPs; and C carbon quantum dots

Inorganic NPs

This class comprises NPs that not made of carbon or organic materials. The typical examples of this class are metal, ceramic, and semiconductor NPs. Metal NPs are purely made of metal precursors, they can be monometallic, bimetallic [ 39 ], or polymetallic [ 40 ]. Bimetallic NPs can be made from alloys or formed in different layers (core–shell) [ 39 ]. Due to the localized surface plasmon resonance characteristics, these NPs possess unique optical and electricals properties [ 25 ]. In addition, some metal NPs also possess unique thermal, magnetic, and biological properties [ 23 ]. This makes them increasingly important materials for the development of nanodevices that can be used in numerous physical, chemical, biological, biomedical, and pharmaceutical applications [ 41 , 42 ] (these applications are discussed in detail later in the applications section of the review). In present days, the size-, shape-, and facet-controlled synthesis of metal NPs is important for creating cutting-edge materials [ 43 ].

Semiconductor NPs are made of semiconductor materials, which possess properties between metals and non-metals. These NPs possess unique wide bandgaps and show significant alteration in their properties with bandgap tuning compared to bulk semiconductor materials [ 25 ]. As a result, these NPs are important materials in photocatalysis, optic, and electronic devices [ 44 , 45 ]. Ceramic NPs are inorganic solids made of carbonates, carbides, phosphates, and oxides of metals and metalloids, such as titanium and calcium [ 46 ]. They are usually synthesized via heat and successive cooling and they can be found in amorphous, polycrystalline, dense, porous or hollow forms [ 25 ]. They are mainly used in biomedical applications due to their high stability and high load capacity [ 47 ]. Nevertheless, they are also used in other applications such as catalysis, degradation of dyes, photonics and optoelectronics [ 46 , 48 ].

Physicochemical properties of NPs

As mentioned earlier, NPs can be used in a long list of applications due to their unique physical and chemical properties that do not exist in their larger-dimension counterparts of the same materials. The following sections summarize the most import physicochemical properties that are changing on the nanoscale.

Mechanical properties

Mechanical properties refer to the mechanical characteristics of a material under different conditions, environments, and various external forces. As for traditional materials, the mechanical properties of nanomaterials generally consist of ten parts: strength, brittleness, hardness, toughness, fatigue strength, plasticity, elasticity, ductility, rigidity, and yield stress [ 49 ]. Most inorganic, non-metallic materials are brittle materials and do not have significant toughness, plasticity, elasticity, or ductility properties. Organic materials on the other hand, are flexible materials and do not necessarily have brittleness and rigidity properties.

Due to surface and quantum effects, NPs display different mechanical properties compared to bulk materials [ 49 ]. For example, conventional FeAl powder which is composed of microparticles (larger than 4 µm), is brittle, while ultrafine FeAl alloy powder displays a good combination of strength and ductility as well as enhanced plasticity [ 50 ]. These new properties are believed to arise due to the diverse interaction forces between NPs or between them and a surface. The most important interaction forces involved are van der Waals forces, which consist of three parts, Keesom force, Debye force, and London force [ 51 , 52 , 53 ]. Other relevant interaction forces are electrostatic and electrical double layer forces, normal and lateral capillary forces, solvation, structural, and hydration forces [ 54 ].

There are different theories on how the interaction forces between NPs give them new mechanical properties, such as the DLVO (Derjaguin–Landau–Verwey–Overbeek) theory, JKR (Johnson–Kendall–Roberts) theory, and DMT (Derjaguin–Muller–Toporov) theory. The DLVO theory combines the effects of van der Waals attraction and electrostatic repulsion to describe the stability of colloidal dispersions [ 54 ]. This theory can explain many phenomena in colloidal science, such as the adsorption and the aggregation of NPs in aqueous solutions and the force between charged surfaces interacting through a liquid medium [ 55 , 56 ]. Nevertheless, the DLVO theory is inadequate for the colloidal properties in the aggregated state [ 54 ].

When the size of objects decreases to the nanoscale, the surface forces become a major player in their adhesion, contact, and deformation behaviors. The JRK theory is applicable to easily deformable, large bodies with high surface energies, where it describes the domination of surface interactions by strong, short-range adhesion forces. In contrast to this, the DMT theory is applicable to very small and hard bodies with low surface energies, where it describes the adhesion being caused by the presence of weak, long-range attractive forces. Although the DLVO, JKR and DMT theories have been widely used to describe and study the mechanical properties of NPs [ 57 , 58 ], it is still a matter of debate whether or not continuum mechanics can be used to describe a particle or collection of particles at the nanometer scale [ 54 ].

Thermal properties

Heat transfer in NPs primarily depends on energy conduction due to electrons as well as photons (lattice vibration) and the scattering effects that accompany both [ 59 ]. The major components of thermal properties of a material are thermal conductivity, thermoelectric power, heat capacity, and thermal stability [ 59 , 60 ].

NP size has a direct impact on electrical and thermal conductivity of NPs [ 60 ]. As the NP size decreases, the ratio of particle surface area respective to its volume increases hyperbolically [ 60 ]. Since the conduction of electrons is one of the two main ways in which heat is transferred, the higher surface-to-volume ratio in NPs provides higher number of electrons for heat transfer compared to bulk materials [ 61 ]. Moreover, thermal conductivity in NPs is also promoted by microconvection, which results from the Brownian motion of NPs [ 62 ]. Nevertheless, this phenomenon only happens when solid NPs are dispersed in a liquid (generating a Nanofluid) [ 63 ]. As an example, the addition of Cu NPs to ethylene glycol enhances the thermal conductivity of the fluid up to 40% [ 64 ].

The thermoelectric power of a material depends on its Seebeck coefficient and electrical conductivity ( \(P={S}^{2}\sigma \) , where P is thermoelectric power, S is the Seebeck coefficient, and \(\sigma \) is the electrical conductivity). The scattering of NPs in bulk materials (doping) is known to enhance the thermoelectric power factor [ 65 ]. This enhancement could come from the enhancement of the Seebeck coefficient or the enhancement of electrical conductivity. The embedding of size-controlled NPs in bulk thermoelectric materials helps to reduce the lattice thermal conductivity and enhances the Seebeck coefficient due to electron energy filtering [ 66 , 67 ]. Generally, the enhancement of electrical conductivity is accompanied by the reduction of the Seebeck coefficient and vice versa [ 65 ] However, the doping of InGaAlAs material with 2–3 nm Er NPs resulted in the significant increase of thermoelectric power of the material through the enhancement of the conductivity while keeping the Seebeck coefficient unchanged [ 65 ]. Depending on NP size, volume fraction, and band offset, a NP-doped sample can either enhance or suppress the electrical conductivity in comparison with undoped bulk sample.

Experimental studies have shown that the heat capacity of NPs exceeds the values of analogous bulk materials by up to 10% [ 68 ], e.g. in the case of Al 2 O 3 and SiO 2 NPs [ 69 , 70 ]. The major contribution to heat capacity at ambient temperatures is determined by the vibration degrees of freedom, i.e., the peculiarities of phonon spectra (vibrational energy that arises from oscillating atoms within a crystal) are responsible for the anomalous behavior of heat capacity of NPs [ 68 ]. NPs usually exhibit a significant decrease in melting temperature compared to their analogous bulk materials [ 71 ]. The main reason for this phenomenon is that the liquid/vapor interface energy is generally lower than the average solid/vapor interface energy [ 72 ]. When the particle size decreases, its surface-to-volume ratio increases, and the melting temperature decreases as a result of the improved free energy at the particle surface [ 73 ]. For instance, the melting temperature of 3 nm Au NPs is 300 degrees lower than the melting temperature of bulk gold [ 14 ]. In addition, NP composition plays an important role in thermal stability. For example, the thermal stability of Au in Au 0.8 Fe 0.2 is significantly higher than of pure Au or Au 0.2 Fe 0.8 [ 74 ]. Generally, bimetallic alloy NPs show higher thermal stabilities and melting temperatures than monometallic NPs due to the alloying effect [ 75 , 76 ].

Magnetic properties

All magnetic compounds include a ‘magnetic element’ in their formula, i.e., Fe, Co, or Ni (at ambient temperatures). There are only three known exceptions that are made from mixed diamagnetic elements, Sc 3 In, ZrZn 2 , and TiBe 2-x Cu x [ 77 , 78 , 79 , 80 ]. Otherwise, elements such as Pd, Au, or Ag are diamagnetic. This all changes in the nanoscale. Several materials become magnetic in the form of NPs as a result of uneven electronic distribution [ 25 ]. For instance, FeAl is not magnetic in bulk but in the form of NPs, it is becomes magnetic [ 50 ], other examples include Pd and Au [ 81 ]. In bulk materials, the key parameters for determining magnetic properties are composition, crystallographic structure, magnetic anisotropy, and vacancy defects [ 82 , 83 ]. However, on the nanoscale, two more important parameters are strongly involved, i.e., size and shape [ 84 ].

One of the interesting size-dependent phenomena of NPs is superparamagnetism [ 84 ]. As the size of the NPs decreases, the magnetic anisotropy energy per NP decreases. The magnetic anisotropy energy is the energy keeping the magnetic moment in a particular orientation. At a characteristic size for each type of NPs, the anisotropy energy becomes equal to the thermal energy, which allows the random flipping of the magnetic moment [ 85 ], in this case, the NP is defined as being superparamagnetic [ 86 ]. Superparamagnetic NPs display high magnetization only in the presence of a magnetic field, and once it is removed they do not retain any magnetization [ 87 ]. Superparamagnetism was long believed to form only in small ferromagnetic or ferrimagnetic NPs [ 88 ], but interestingly, other paramagnetic materials show magnetism in the nanoscale too [ 81 ].

NP size effects can also be observed in changes in magnetic coercivity, i.e., the resistance of a magnetic material to changes in magnetization (Fig.  4 ). In contrast to large particles or bulk materials, which possess multiple magnetic domain structures, small NPs possess single magnetic domain structures below a certain critical radius (r c ), where all magnetic spins in the NP align unidirectionally (blue arrows in Fig.  4 ). However, the NP radius has to be lower than the threshold radius for superparamagnetism (r sp ) in order to be superparamagnetic [ 89 ]. In the single-domain regime, between r sp and r c , the magnetic coercivity increases as the size of the NP increases until it reaches the maximum at r c [ 84 ]. In this size regime, due to the high magnetic coercivity, the NPs behave similarly as their larger dimension counterparts despite having a single domain structure, i.e., they become ferromagnetic for ferromagnetic materials or paramagnetic for paramagnetic materials etc . Above r c , the magnetic coercivity starts to decrease when multiple magnetic domains are formed in a single NP. The critical radius represents the size where it is energetically favored for the NP to exist without a domain wall [ 86 ]. The calculated critical radii for some common magnetic materials are 35 nm of Ni, 8 nm for Co, and 1 nm for Fe [ 90 ]. Above that point, multi-domain magnetism begins in which a smaller reversal magnetic field is required to make the net magnetization zero [ 84 ].

figure 4

The change in magnetic coercivity of NPs as a function of particle radius. Figure adapted from Kalubowilage et al., 2019 [ 89 ]. rc critical radius, rsp threshold radius for superparamagnetism

The second key parameter for determining the magnetic properties of NPs is the shape of NPs. In comparison to the size parameter, there is significant less research on the effect of shape on the magnetic properties of NPs having the same volume [ 86 ]. However, large differences in coercivity were found between a set of cubic and spherical CoFe 2 O 4 NPs [ 91 ]. Unlike the curved topography in spherical CoFe 2 O 4 NPs, cubic CoFe 2 O 4 NPs have fewer missing oxygen atoms, and it was hypothesized that this led to less surface pinning and to lower coercivity for the cubic structures [ 86 ]. Other studies also found differences in magnetism between spherical and cubic Fe 3 O 4 NPs [ 92 , 93 ].

Similar to bulk materials, the composition also affects the magnetism of NPs. The magnetocrystalline phase of the NP is significant in determining its magnetic coercivity [ 94 ]. This effect can be observed in magnetic bimetallic core–shell or alloy NPs with anisotropic crystalline structures. For example, Co@Pt core–shell NPs composed of an isotropically structured face-centered cubic Co core and a non-magnetic Pt shell exhibit superparamagnetic behavior with zero coercivity at room temperature [ 95 ]. In general, the compositional modification of NPs by the adoption of magnetic dopants is known to significantly change the magnetism of NPs [ 96 ].

Electronic and optical properties

Metallic and semiconductor NPs possess interesting linear absorption, photoluminescence emission, and nonlinear optical properties due to the quantum confinement and localized surface plasmon resonance (LSPR) effect [ 97 , 98 ]. LSPR phenomena arise when the incident photon frequency is constant with the collective excitation of the conductive electrons [ 25 ].Due to this phenomenon, noble metal NPs exhibit a strong size-dependent UV–visible extinction band that is not present in the spectra of bulk metals. Generally, the optical properties of NPs depend on the size, shape, and the dielectric environment of the NPs [ 99 ].

The collective excitations of conductive electrons in metals are called plasmons [ 100 ]. Depending on the boundary conditions, bulk plasmons, surface-propagating plasmons, and surface-localized plasmons are distinguished (Fig.  5 A–C). Because of their longitudinal nature, the bulk plasmons cannot be excited by visible light. The surface-propagating plasmons propagate along metal surfaces in a waveguide-like fashion [ 98 ]. In the case of NPs, when they are irradiated by visible light, the oscillating electric field causes the conductive electrons to oscillate coherently. When the electron cloud is displaced relative to the nuclei, a restoring force rises from Coulomb attraction between electrons and nuclei that results in oscillation of the electron cloud relative to the nuclear framework [ 99 ]. This creates uncompensated charges at the NP surface (Fig.  5 D). As the main effect producing the restoring force is the polarization of the NP surface, these oscillations are called surface plasmons and have a well-defined resonance frequency [ 98 ].

figure 5

Graphical illustration of the types of plasmons. A bulk; B surface propagating; and C surface localized plasmons (adapted from Khlebtsov et al., 2010 [ 98 ]). D graphical illustration of the localized surface plasmon resonance (LSPR) in NPs (adapted from Kelly et al., 2003 [ 99 ])

Experimental studies on Ag NPs showed significant differences in their optical properties based on the size of NPs. For Ag NPs with 30 nm radius, the main extinction peak was at 369 nm wavelength, while for Ag NPs with 60 nm radius, a totally different behavior was observed [ 99 ]. The same researchers found that the shape of the NPs also is critical for the optical properties, the plasmon resonance wavelength shifts to the red as the NPs become more oblate [ 99 ], demonstrating that plasmon resonance strongly depend on NPs shape. With respect to the dielectric environment of the NPs, both the surrounding solvent and the support (substrate) were found to be critical for the optical properties. For Ag NPs, both experimental and theorical studies on the effect of surrounding solvent show that plasmon wavelength linearly depends on the refractive index of the solvent [ 99 , 101 ]. At the same time, 10 nm Ag NPs supported on mica substrates displayed LSPR wavelength shifts to the red compared to unsupported NPs [ 102 ]. The biogenic synthesis of NPs can also improve the optical properties. Biologically produced CeO 2 NPs using Simarouba glauca leave extract were found to have different absorption bands and higher band gap energies compared to chemically produced CeO 2 NPs. These superior optical properties were attributed to the better crystallinity and small size of biogenic NPs compared to chemical NPs [ 103 ]. Biogenic NPs can also offer higher photocatalytic activities, e.g., ZnO NPs produced by Plectranthus amboinicus leaf extract had higher photocatalytic activity in the photodegradation of methyl red under UV illumination compared to chemical produced ZnO NPs [ 104 ].

Catalytic properties

Nano-catalysis, i.e., the use of NPs as catalysts, is a quickly evolving field within chemical catalysis. Significantly enhanced or novel catalytic properties such as reactivity and selectivity have been reported for NP catalysts compared to their bulk analogues. The catalytic properties of NPs depend on the size, shape, composition, interparticle spacing, the oxidation state, and the support of the NPs [ 76 ].

The dependency of catalytic activity on the size of NPs is well studied. The relation is an inverse one, i.e., the smaller the NPs the more catalytically active they are. This relationship was found e.g., in the electro-catalysis oxidation of CO by size-selected Au NPs (1.5, 4, and 6 nm) deposited on indium tin oxide. The researchers observed that the smallest NPs provided the highest normalized current densities [ 105 ]. The same relationship was also found in several other studies [ 106 , 107 , 108 , 109 , 110 ]. Goodman et al., 1998 [ 111 ] speculated originally that this behavior could be attributed to quantum-size effects generated by the confinement of electrons within a small volume. Later, size-dependent changes in the electronic structure of the clusters [ 112 ] and the resulting larger number of low-coordinated atoms available for interaction by the larger surface-to-volume ratios with smaller NPs were discussed [ 76 ].

The shape is also known to affect the reactivity and selectivity of the NPs. For the oxidation of CO by Au NPs, hemispherical NPs were found to be more active than spherical ones [ 113 ]. For the oxidation of styrene by Ag NPs, nanocubes were found to be fourteen times more efficient than nanoplates and four times more efficient than nanospheres [ 114 ]. The reason for these dramatical changes are attributed to the increase/decrease in the relative area of the catalytically active surface facets [ 76 ] or to the differences in stability for different NP shapes [ 115 ].

As for composition, several studies have shown that the use of alloys in NPs can enhance the catalytic activity as a result of the alloying effect causing changes in the electronic properties of the catalyst, decreasing poisoning effects, and providing distinct selectivities [ 76 ]. For example, the alloying of Pt with other metals such as Ru, Ni, and Co, was reported to enhance the hydrogenation and oxygen reduction activity of the NP catalyst material, as well as enhancing the resistance against CO poisoning [ 116 , 117 , 118 ]. However, the alloying of Pt with Fe, Ru, and Pd, resulted in reduced reactivity for methanol decomposition [ 119 ]. This reduction in reactivity was explained by the possible occupation of the surface with the addition metal atoms, since pure Fe, Ru, and Pd clusters are less reactive for methanol decomposition than similarly-sized pure Pt clusters. In general, the change in the composition of NPs changes the electronic structure of metal surfaces by the formation of bimetallic bonds as well as the modification of metal–metal bond lengths [ 76 ]. In addition, the charge-transfer phenomenon between different metals may favorably change the binding energy of adsorbents, lower the barriers for specific chemical reactions, and enhance resistance against poisoning [ 120 , 121 , 122 ].

The catalytic activity and stability of 2 nm Au NPs dispersed on polycrystalline TiC films displayed a strong dependence on interparticle spacing. In this study, Au NPs having two different interparticle spacing (30 and 80 nm) were analyzed by Thermal Desorption Spectroscopy. It was found that the sample with smaller interparticle spacing was poisoned and subsequently deactivated while the sample with longer interparticle spacing showed longer lifetime [ 123 ]. At the same time, the oxidation state of NPs was shown to affect the catalytic activities. Ru NPs under rich O 2 conditions and moderate temperatures oxidize and form RuO 2 , the reaction of CO oxidation was found to occur on the metal oxide surface not the metal surface [ 124 ]. A similar effect on CO oxidation was also observed with Pt NPs in which the reactivity of PtO 2 was found to be higher than Pt [ 125 ]. The reaction of CO oxidation was compared for several metal NPs (Ru, Pd, Ir, Os, and Pt) and their corresponding oxides, and the oxides were indeed more reactive than the metals [ 126 , 127 ]. The superior catalytic performance of RuO 2 over their metallic counterparts is generally agreed on, nevertheless, the same cannot be said for other catalytically active metals such as Pt [ 76 ]. In general, these differences in catalytic performance are attributed to the electron transfer processes at the metal/metal oxide interfaces. Consequently, the view that NP oxidation is an undesirable process that leads to the reduction of catalytic performance needs to be reconsidered [ 128 ].

An example for the effect of the support material is the role of the MgO support for Au NPs, where MgO was found to be important for CO oxidation and particularly, for controlling the rate of CO oxidation through oxygen vacancies [ 129 ]. Later, the process of electron charge transfer from oxygen vacancies at the metal-substrate interface of supported Au NPs was suggested to be an ideal environment for O 2 activation and oxidation reactions [ 130 ]. A similar behavior was also found in the decomposition of SO 2 and dissociation of water by Au NPs supported on CeO 2 , in which CeO 2 supports played a critical role [ 131 ]. The experiments showed that not only the chemical composition of the support affects the reactivity of the catalyst, but the crystal structure of the support, too [ 132 ]. Enhanced catalytic performance for CO oxidation and SO 2 dissociation have also been reported for Au NPs supported on metal carbides such as TiC [ 108 , 133 ]. In addition to enhanced catalytic reactivities, the support also plays an important role in NP stabilization [ 106 ], i.e., the stabilization of NPs against coarsening, the stabilization of metal oxides at the NP surface, and the stabilization of intermediate reactions species [ 76 ].

Characterization of NPs

The properties of NPs determine their potential applications. Hence, different methods and techniques are used for the analysis and characterization of the various physicochemical properties of NPs. Table 1 summarizes all characterization techniques mentioned in this review and shows what properties and features can be resolved by each technique.

Morphological and topographical characterization

The morphological and topographical features of NPs are of great interest since they influence most of the properties of NPs as described above. These features include the size, shape, dispersity, localization, agglomeration/aggregation, surface morphology, surface area, and porosity of the NPs. The following techniques are regularly used for the characterization of morphological and topographical features of NPs.

Electron microscopy (EM)

Scanning electron microscopy (SEM), scanning tunneling microscopy (STM), and transmission electron microscopy (TEM) are frequently employed for the analysis of NP size, shape, and surface. In SEM, an electron gun is used to produce a beam of electrons that is controlled by a set of lenses to follows a vertical path through the microscope until it hits the samples. Once the sample is hit by the beam, electrons and X-rays are ejected from the sample. Detectors are then used to collect the X-rays and scattered electrons in order to create a 3D image of the sample. SEM provides different information about the NPs such as size, shape, aggregation, and dispersion [ 134 ]. Similarly, TEM provides information about the size, shape, localization, dispersity, and aggregation of NPs in two-dimensional images [ 25 ]. TEM employs an electromagnetic lens that focuses a very fine beam of electrons into an ultrathin section of the sample. This beam passes through the specimen where the electrons either scatter or penetrate the sample and hit a fluorescent screen at the bottom of the microscope. The difference in electron densities is used for the contrast to create an image of the specimen. TEM can be also used for the characterization of NP crystal structure through the use of selected area electron diffraction (SAED), where the electron beam is focused on a selected area in the sample and the scattered electrons are used to obtain a diffraction pattern. STM is based on the phenomenon of quantum tunneling, where a metallic tip is brough very close to the sample surface and used to apply voltage. When voltage is applied, electrons from the sample surface are extracted creating an electrical current that is used to reconstruct an image of the surface with atomic resolution [ 135 ]. STM is mainly used to characterize the topography of NPs. For inorganic NPs, these techniques offer excellent approaches for the determination of morphological features of NPs. For organic NPs (or NPs coated with biological materials), these techniques require sophisticated sample preparations which constitute major restrictions to their use [ 136 ]. The sample preparation for these techniques might cause sample dehydration, which might lead e.g. to sample shrinking and aggregation [ 136 ].

Examples: TEM was used for the characterization of Ag NPs produced by Arbutus unedo leaf extract. In this example, the NPs have a spherical morphology with a uniform size of 30 nm. The NPs were found to agglomerate into small aggregates, each including 5–6 NPs. At the same time, the SAED approach was used to determine the crystal structure of the NPs. The majority of the NPs were found to be single crystalline cubic materials predominately oriented along their (111) direction [ 137 ]. For the characterization of Ag NPs produced by Diospyros kaki leaf extract, SEM helped to show that the NPs were also spherical and the size was 32 nm with some deviations [ 138 ]. STM is less frequently used for the characterization of biogenic NPs. The features of Ag NPs produced by lime, sweet-lime, and orange juices were compared using STM technique [ 139 ].

Dynamic light scattering (DLS)

This technique is a common approach for the analysis of NP size and size distribution. This approach involves the measurement of light interference based on the Brownian motion of NPs in suspension, and on the correlation of NP velocity (diffusion coefficient) with their size using Strokes-Einstein equation [ 140 ]. The size distribution range of NPs is shown as the polydispersity index, which is the output of an autocorrelation function [ 136 ]. The polydispersity index values lie between 0 and 1, where 0 represents a completely homogenous population and 1 represents a highly heterogeneous population. This technique also allows the analysis of non-spherical NPs through the use of multistage DLS [ 136 ]. This technique is also referred to as photon correlation spectroscopy (PCS) [ 141 ].

Examples: DLS was used to measure the size and the size distribution profile of a wide range of biogenic NPs. The average size of Ag NPs produced by Trichoderma koningii fungi was found to be around 25 nm and the size distribution profile was between 14 and 34 nm. The polydispersity index for those NPs was 0.681, which indicates that they are polydispersed [ 142 ]. While the average size of Ag NPs produced by potato ( Solanum tuberosum ) was found to be around 10–12 nm with a wider distribution profile between 3–65 nm [ 143 ]. In a different application, DLS was employed to study the size increase of biogenic MnO 2 NPs overtime, demonstrating that their size is 7.5 nm after 3 min of the initiation of the reaction, then their size grows overtime until it become 54 nm after 31 min [ 144 ].

Nanoparticle tracking analysis (NTA)

This method is used for the analysis of NP size in suspensions based on their Brownian motion. Like in DLS, the rate of NP movement is correlated with their size using Strokes-Einstein equation, allowing the measurement of size distribution profiles for NPs with 10–1000 nm diameter. Its advantage over DLS is that NP motion is analyzed by video. Individual positional changes of NPs are tracked in two dimensions, which are used to determine NP diffusion rates, and by knowing the diffusion coefficient, the hydrodynamic diameter of the particles can be calculated. In DLS, individual NPs are not visualized, but instead, the time-dependent intensity fluctuations caused by Brownian motion are used to calculate the polydispersity index [ 145 ]. NTA was found to be more precise for sizing monodisperse as well as polydisperse organic NPs compared to DLS [ 146 ].

Examples: NTA was used to measure the size and dispersity of Ag NPs produced by Camellia sinensis (green tea) powder, the NPs were found to be well dispersed in an aqueous medium with an average size of 45 ± 12 nm [ 147 ]. For Se NPs produced by lactic acid bacteria, NTA was employed to measure the size and the concentration of NPs. The average size was found to be 187 ± 56 nm with a concentration of (4.67 ± 0.30) × 10 9 Se NPs per ml [ 148 ].

Brunauer–Emmett–Teller (BET) method

This method is based on the adsorption and desorption principle developed by Stephen Brunauer, Paul Emmett, and Edward Teller, and it is considered one of the best methods for the analysis of NP surface area [ 25 ]. In BET analysis, a partial vacuum is created to produce adsorption between the sample and liquid N 2 (because the interaction between solid and gaseous phases is weak, the surface is cooled with liquid N 2 to obtain detectable amounts of adsorption). After the formation of adsorption monolayers, the sample is removed from the N 2 atmosphere and heated to cause the adsorbed N 2 to be released from the material (desorption) and quantified. The data collected is displayed in the form of isotherms (graphs representing the amount of N 2 adsorbed as a function of relative pressure at a constant temperature). The data is displayed in five isotherms where the information is used to determine the surface area of the sample [ 25 , 149 ]. Figure  6 graphically illustrates the principle of this method.

figure 6

Principles of the BET and BJH methods. The BET method (steps 1–3) is based on the adsorption of nitrogen on the NP surface. After the formation of a monolayer, nitrogen is desorbed, and the surface area is calculated. The BJH method (steps 1, 2, 4, and 5) is based on the complete filling of NP pores with liquid nitrogen. When saturation is reached, nitrogen is desorbed, and pore size is calculated

Examples: The BET method was employed to measure the surface area of CeO 2 NPs produced by Eucalyptus globulus leaf extract. The surface area was found to be 40.96 m 2 /g of biogenic CeO 2 NPs, much higher than the commercial CeO 2 NPs (8.5 m 2 /g) [ 150 ]. BET was also used to measure the surface area of SiO 2 NPs produced by rice husk, CuO NPs produced by Leucaena leucocephala leaf extract, and Ag NPs produced by Acanthospermum hispidum leaf extract. In these examples, the surface area was 7.15 m 2 /g, 47.54 m 2 /g, and 9.91 m 2 /g, respectively [ 151 , 152 , 153 ].

Barrett–Joyner–Halenda (BJH) method

This method is based on the Barrett–Joyner–Halenda principle and is used for the determination of porosity (or pore size) of NPs. Similar to the BET method, this method also involves the use of N 2 gas to adsorb to the sample. In the BJH method, the process is extended so the gas condensates in the sample pores as pressure increases. The pressure is increased until a saturation point is achieved, at which all the pores of the sample are filled with liquid. Afterwards, the condensated gas is allowed to evaporate where the desorption data is calculated and correlated to the pore size using a modified Kelvin equation (Kelvin model of pore filling) [ 154 , 155 ]. Figure  6 graphically illustrates this method.

Examples: The BJH method was employed to study the pore size of a wide range of biogenic NPs, for instance, the pore size of CeO 2 NPs produced by Eucalyptus globulus leaf extract was found to be 7.8 nm [ 150 ], the pore size of CuO NPs produced by Leucaena leucocephala leaf extract was 2.13 nm [ 152 ], the pore size of SiO 2 NPs produced by rice husk and Ag NPs produced by Acanthospermum hispidum leaf extract were much larger, being 29.63 nm and 36.34 nm, respectively [ 151 , 153 ].

Structural and chemical characterization

The structural characterization of NPs and the study of their composition is of high interest due to the strong influence of these parameters on the physicochemical properties. The following techniques are commonly used for the analysis of NP composition, phase, crystallinity, functionalization, chemical state (oxidation), surface charge, polarity, bonding, and electrochemical properties.

X-ray diffraction analysis (XRD)

This technique is based on irradiating a material with incident X-rays and then measuring the intensities and scattering angles of the X-rays that leave the material [ 156 ]. This technique is widely used for the analysis of NP phase and crystallinity. However, the resolution and accuracy of XRD can be affected in cases where the samples have highly amorphous characteristics with varied interatomic distances or when the NPs are smaller than several hundreds of atoms [ 25 ].

Examples: For the characterization of biogenic Ag NPs, the XRD results of Ag NPs produced by Trichoderma koningii [ 142 ], Solanum tuberosum [ 143 ], and Acanthospermum hispidum leaf extract [ 153 ] displayed characteristic peaks occurring at roughly 2θ = 38 o , 44°, and 64 o corresponding to (111), (200), and (220) planes, respectively. These results are in good agreement with the reference to the face-centered cubic structure of crystalline silver. However, the XRD results of Ag NPs produced by Solanum tuberosum were not as clear as the other biogenic Ag NPs and had several impurities. The structural characterization of Pd NPs produced by Garcinia pedunculata Roxb leaf extract by XRD showed the distinct peaks of Pd, however, three other peaks were also observed at 2θ of 34.22˚, 55.72˚, and 86.38˚, indicating the presence of PdO phases along with Pd NPs [ 157 ].

Energy-dispersive X-ray spectroscopy (EDX)

This technique is based on the irradiation of the sample with an electron beam. Electrons of the electron beam when incident on the sample surface eject inner shell electrons, the transition of outer shell electrons to fill up the vacancy in the inner shell produces X-rays. Each element produces a characteristic X-ray emission pattern due to its unique atomic structure, and therefore can be used to perform compositional analysis [ 158 ]. The shortfall of EDX is that the resulting spectra give only qualitative compositional information (it shows the chemical elements present in the sample without quantification). However, the peak intensities to some extent give an estimate of the relative abundance of an element in a sample [ 159 ]. This technique does not require sophisticated additional infrastructures, usually it is a small device that is connected to an existing SEM or TEM. This allows the use of SEM or TEM for the morphological characterization and EDX is used simultaneously for the analysis of chemical composition [ 160 ].

Examples: The EDX technique is usually used for the confirmation of the presence of the element in question in biogenic NPs. For instance, EDX was used to confirm the presence of Au in Au NPs produced by Jasminum auriculatum leaf extract [ 161 ], the presence of Pd in Pd NPs produced by Pulicaria glutinosa extract [ 162 ], the presence of Te in Te NPs produced by Penicillium chrysogenum PTCC 5031 [ 163 ], and the presence of Ag in Ag NPs produced by Trichoderma viride [ 164 ].

High-angle annular dark-field imaging (HAADF)

This method is used for the elemental mapping of a sample using a scanning transmission electron microscope (STEM). The images are formed by the collection of incoherently scattering electrons with an annular dark-field detector [ 165 ]. This method offers high sensitivity to variations in the atomic number of elements of the sample, and it is used for elemental composition analysis usually when the NPs of interest consist of relatively heavy elements. The contrast of the images is strongly correlated with atomic number and specimen thickness [ 166 ].

Examples: The employment of HAADF-STEM in the characterization of biogenic Au–Ag–Cu alloy NPs confirmed the presence of the three elements in the same NP [ 167 ]. Similarly, this approach revealed that Ag NPs produced by Andrographis paniculata stem extract were coated with an organic polymer [ 168 ]. The employment of this approach in the characterization of Cu NPs produced by Shewanella oneidensis revealed that Cu NPs remained stable against oxidization under anaerobic conditions, but when they were exposed to air a thin shell of Cu 2 O develop around the NPs [ 169 ].

X-ray photoelectron spectroscopy (XPS)

This technique is considered the most sensitive approach for the determination of NP exact elemental ratios, chemical state, and exact bonding nature of NP materials [ 25 ]. XPS is based on the photoelectric effect that can identify the elements within a material, or covering a material, as well as their chemical state with high precision [ 170 ]. XPS can also be used to provide in-depth information on electron transfer, e.g., for Pt NPs supported on CeO 2 , it was found that per ten Pt atoms only one electron is transferred to the support [ 171 ].

Examples: The XPS technique can employed for different purposes. For instance, it was used for measuring the purity of Au NPs produced by cumin seed powder [ 172 ]. XPS was used for the determination of the oxidation states of Pt NPs produced by Nigella sativa seeds and Ag NPs produced by Rosa canina . XPS results of Pt NPs showed the presence of three oxidation states for Pt (Pt (0), Pt (II), and Pt (IV)) and two oxidation states for Ag NPs (Ag (0) and Ag (I)). In both cases, the zero-oxidation state was the abundant one, the presence of a small amount of the other oxidation states suggests that some of the NPs were oxidized or had unreduced species [ 173 , 174 ]. XPS was used for the determination of the exact elemental ratios and the bonding nature of FeS NPs produced by Shewanella putrefaciens CN32. For the exact elemental ratios, the researchers compared biogenic and abiotic FeS NPs and found that biogenic FeS NPs had a 2.3:1 Fe:S ratio while the abiotic NPs had a 1.3:1 Fe:S ratio. For the bonding nature, it was determined that the surface of NPs had Fe(II)-S, Fe(III)-S, Fe(II)-O, and Fe(III)-O bonds [ 175 ].

Fourier-transform infrared spectroscopy (FTIR)

This technique is based on irradiating a material with infrared light, where the absorbed or transmitted radiation is recorded. The resulting spectrum represents a unique fingerprint of samples, where information about the nature of the sample can be obtained such as the bonds involved, polarity, and oxidation state of the sample [ 176 , 177 ]. This technique is mainly used for the characterization of organic materials such as the surface chemical composition or functionalization of NPs. It is also used for the identification of contaminants when high purity is sought [ 178 ].

Examples: For biogenic NPs, FTIR is usually used for the identification of probable functional groups present on the surface of NPs that are responsible for the reduction and stabilization of the NPs. For plant-mediated NP synthesis, for instance for Ag NPs produced by Camellia sinensis , the FTIR results indicate the presence of Camellia sinensis phytocompounds, such as caffeine and catechin, on the surface of Ag NPs that could be responsible for the reduction of Ag or act as stabilizing agents [ 147 ]. For Ag NPs produced by Solanum tuberosum , the NPs were found to be capped by amide and amine groups [ 143 ]. For CeO 2 NPs produced by Eucalyptus globulus , the polyphenol groups present in Eucalyptus globulus extract were found on the surface of NPs suggesting their involvement in the reduction/stabilization process [ 150 ]. For microbe-mediated NP synthesis, FTIR results show the presence of protein residues on the surface of NPs confirming the involvement of different proteins in the reduction/stabilization process, such as in Ag NPs produced by Streptomyces sp. NH28 [ 179 ], in Te NPs produced by Penicillium chrysogenum PTCC 5031 [ 163 ], and in Se NPs produced by Azospirillum thiophilum [ 180 ].

Zeta potential analysis

Zeta potential measurements are used for the determination of NP surface charge in colloidal solutions. The surface charge of NPs attracts counter-ions that form a thin layer on the surface of the NPs (called Stern layer). This layer travels with the NPs as they diffuse thought the solution. The electric potential at the boundary of this layer is known as NP zeta potential [ 136 ]. The instruments used to measure this potential are called zeta potential analyzers [ 181 ]. Zeta potential values are indicative for NP stability, where higher absolute value of zeta potential indicate more stable NPs [ 136 ].

Examples: The zeta potential is a good indicator for the stability of NPs, where NPs with zeta potentials of more than + 30 mV or less than − 30 mV are considered stable. Zeta potentials have been measured for a wide range of biogenic NPs. The zeta potential for Ag NPs produced by Ziziphus jujuba leaf extract of − 26.4 mV [ 182 ]. Ag NPs produced by other organisms have different zeta potential values, for example, Ag NPs produced by Punica granatum peel extract have a zeta potential of − 40.6 mV indicating their higher stability [ 183 ], while Ag NPs produced by Aspergillus tubingensis have a zeta potential of + 8.48 indicating their relative instability [ 184 ]. The pH of the sample is another important parameter for zeta potential values, the higher pH the lower the zeta potential value [ 185 ]. Having different zeta potential values for the same type of NPs depending on the organism used for their synthesis is not unique to silver, Se NPs also show different potential values depending on the organism used for their synthesis [ 186 ].

Cyclic voltammetry (CV)

CV is an electrochemical technique for measuring the current response of redox-active solutions to a linearly cycled potential sweep between two or more set values. The CV technique involves the use of three electrodes: a working electrode, reference electrode, and counter electrode. These electrodes are introduced to an electrochemical cell filled with an electrolyte solution and where voltage is in excess, the potential of the working electrode is cycled and the resulting current is measured. This technique is used for determining information about the reduction potential of materials, the kinetics of electron transfer reactions, and the thermodynamics of redox processes [ 187 , 188 , 189 ].

Examples: The CV technique can be employed for two different purposes in the context of biogenic NP characterization. Firstly, it can be used for measuring the stability of NPs in electrocatalysis. For this purpose, the biogenic NPs are assembled on an electrode of the electrolysis cell and are tested for their electrocatalytic behavior against a redox reaction over different cycles. As an example, Ag NPs produced by Citrus sinensis were found to be stable in phenolic compounds redox reactions over multiple cycles [ 190 ]. Secondly, CV can be used for monitoring the progress of reduction of metallic NPs or for the determination of the reducing agent involved in the reduction. For example, for Ag NPs produced by Indian propolis, four cyclic voltammograms were recorded, one for a water extract of Indian propolis, another for an ethanol extract of Indian propolis, and two for the constituent flavonoids of Indian propolis (pinocembrin and galangin). The four cyclic voltammograms showed similar behaviors indicating the involvement of these flavonoids in the reduction of Ag and in forming Ag NPs [ 191 ].

Raman spectroscopy

This technique is based on irradiating a sample with monochromatic light emitted by a laser, in which the interactions between the laser light and molecular vibrations (photons and phonons) are recorded. The technique records the inelastically scattered photons, known as Raman scattering (named after the Indian physician C. V. Raman) [ 192 ]. The output of this technique is a unique fingerprint for each sample, which is used to characterize the chemical and intramolecular bonding of the sample. It can also be used to characterize the crystallographic orientation of the sample [ 193 ]. Surface-enhanced Raman spectroscopy (SERS) enhances Raman scattering of a sample and provides a more sensitive, specific, and selective technique for identifying molecular structures [ 194 ]. Both techniques are also used for the characterization of optical properties, where the recorded photons and phonons are used to understand the plasmonic resonance of NPs [ 25 ].

Examples: Raman spectroscopy was used to characterize Fe 3 O 4 NPs produced by Pisum sativum peel, the researchers found that the NPs were Fe 3 O 4 NPs with face centered cubic phase which was in agreement with their XRD measurements [ 195 ]. Other researchers used Raman spectroscopy for studying the trace deposits of carbohydrates on ferrihydrite NPs produced by Klebsiella oxytoca , the results showed that the pores of NPs had more deposits of carbohydrates that the surface of the NPs [ 196 ]. For Au NPs produced by Raphidocelis subcapitata (green algae), several biomolecules were suggested for their involvement in this process. SERS technique was used to study Au NPs surface-associated biomolecules in order to narrow down the list of biomolecules involved in the bioproduction process. The researchers found that several biomolecules such as, glutathione, β-carotene, chlorophyll a, hydroxyquinoline, and NAD were associated with Au NPs surface, thus, ruling out other molecules such as, glutaraldehyde fixing agent, saccharides, FAD, lipids, and DNA from the list [ 197 ].

Characterization of optical, electronic, and electrical properties

In addition to Raman spectroscopy and SERS, also other techniques can be employed to study and characterize the optical properties of NPs. These techniques give information about the absorption, reflectance, fluorescence, luminescence, electronic state, bandgap, photoactivity, and electrical conductance properties of NPs.

Ultraviolet–visible spectroscopy (UV–vis) and photoluminescence spectroscopy (PL)

In absorption spectroscopy such as UV–vis, the transition of electrons from the ground state to an excited state is measured, while in photoluminescence spectroscopy, the transition of electrons from the excited state to the ground state is measured [ 198 ]. UV–vis spectroscopy uses visible and UV light to measure the absorption or reflectance of a sample. In photoluminescence spectroscopy, usually UV light is used to excite the electron and then measure the luminescence or fluorescence properties of a sample [ 199 ].

Examples: UV–vis spectroscopy is a simple and common technique that is used for the characterization of the optical properties of NPs. For instance, for the characterization of the optical properties of Ag NPs produced by Trichoderma viride , the UV–vis spectrum showed that a Ag surface plasmon band occurs at 405 nm, which is a characteristic band for Ag NPs. The intensity of this band over the reaction time increased as a result of increasing Ag NP concentration in the solution. In the same study, the photoluminescence properties of these NPs were recorded, with an emission in the range between 320–520 nm, which falls in the blue-orange region [ 164 ]. For biogenic Cu NPs, the common absorption peaks are located between 530–590 nm. The difference in NP size and the bio-active molecules used for the reduction process are believed to be the reasons behind the differences in the absorption peaks [ 200 ]. For instance, 15 nm spherical Cu NPs produced by Calotropis procera have an absorption peak at 570 nm [ 201 ], while 76 nm spherical Cu NPs produced by Duranta erecta have an absorption peak at 588 nm [ 202 ]. The same applies to photoluminescence effects, where 27 nm spherical Cu NPs produced by Tilia extract emit light of 563 nm (dark brown) [ 203 ], while 19 nm spherical Cu NPs emit light of 430 nm (green) [ 204 ].

UV–vis diffuse reflectance spectroscopy (DRS)

This technique uses UV and visible light to measure the diffuse reflectance of a material (the reflection of light in many angles, as opposed to specular reflection). The resulting diffuse reflectance spectra are used to determine the electronic state of a sample, which is then used to calculate the bandgap [ 25 ]. Bandgap determination is crucial for determining conductance and photocatalytic properties especially for semiconductor NPs [ 205 ].

Examples: The DRS technique was used to calculate the bandgap for a wide range of biogenic NPs. For instance, TiO 2 NPs produced by Andrographis paniculata exhibit an optical energy bandgap of 3.27 eV [ 206 ]. Interestingly, biogenic ZnO NPs produced by different organism show different bandgaps, for example, ZnO NPs produced by Pseudomonas putida have a bandgap of 4 eV [ 207 ], while ZnO NPs produced by Calotropis procera leaf extract have a bandgap of 3.1 eV [ 208 ].

Spectroscopic ellipsometry

This technique is based on irradiating a sample with polarized light to measures changes in polarization. It is widely used to calculate the optical constants of a material (refractive index and extinction coefficient) [ 209 ]. This technique is also used to characterize the electrical conductivity and dielectric properties of materials [ 210 ].

Examples: Spectroscopic ellipsometry is not a common technique for the characterization of biogenic NPs. For chemically produced NPs, the optical properties for different-sized Au NPs partially embedded in glass substrate were measured by spectroscopic ellipsometry. In this example, a clear transition from LSPR to SPR mode was found as the thickness increases. Moreover, the partially-embedded Au NPs had much higher refractive index sensitivity compared to Au NPs fully immobilized in a glass substrate [ 211 ]. Spectroscopic ellipsometry was also used to measure the changes in the optical constants of a layer of 5 nm ZnO NPs induced by UV illumination. In this case, it was found that the UV illumination of ZnO NPs in inert atmospheres resulted in a clear blue shift in the absorption (Moss-Burstein shift). The UV illumination of ZnO NPs results in the desorption of O 2 from the NPs surface leading to the population of the lowest levels in conduction band with mobile electrons. This phenomenon is reversible, in which the exposure to O 2 from air results in the scavenging of these mobile electrons [ 212 ].

Characterization of magnetic properties

The magnetic properties of NPs are of high importance, as they potentially give NPs great advantages in catalysis, electronics, and medical applications. Several techniques were developed for the detection and quantification of small magnetic moments in NPs.

Magnetic force microscopy (MFM)

This technique is a variety of atomic force microscopy (AFM), in which a magnetic tip is used to scan the sample. The magnetic tip is approached very close to the sample, where the magnetic interactions between the tip and the sample are recorded [ 213 ]. At closer distances to the sample (0–20 nm), other forces such as van der Waals forces also interact with the tip. Therefore, MFM measurements are often operated with two-pass scanning method (also called lift height method) [ 214 ] (Fig.  7 ). In this method, the tip is firstly used to measure the topography of the sample including the molecular forces as van der Waals. Afterwards, the tip is lifted and a second scan is operated following the same topography outline. In the second scan, the short-ranged van der Waals forces disappear and the long-range magnetic forces are almost exclusively recorded. In an experimental study, researchers found that 22 nm was the optimal scanning height for the second scan, at which van der Waals forces are very weak while the distance is still small enough to measure the magnetic interactions for Pd-Fe bimetallic NPs [ 215 ].

figure 7

Magnetic force microscopy lift height method. The first scan is done very close to the surface to obtain the topography of the sample. Then, the tip is lifted and a second scan is performed following the topography outline obtained in the first scan

Examples: MFM was heavily used for the characterization of magnetite NPs produced by magnetotactic bacteria. For instance, the size and orientation of the magnetic moment of magnetite NPs produced by Magnetospirillum gryphiswaldense strain MSR-1 were studied by MFM [ 216 ], in which the size of the magnetic moment was found to be 1.61 × 10 −17 Am 2 . In a different study, MFM was used to characterize the magnetic properties and to estimate the size of the magnetic kernel of the magnetosomes produced by the same strain, and it was determined that the NPs behaved like single mono-domain nanomagnets [ 217 ]. The magnetic properties of NPs made from materials such as Pd that only exhibit significant magnetism on the nanoscale can also be studied by MFM, however, the magnetic moment of these NPs is much lower than for ferromagnetic NPs. The magnetic decoration of Pd NP samples with Fe 2 O 3 NPs strongly enhances the weak magnetic signal of Pd NPs up to 15 times [ 218 ]. This approach could make the MFM technique useful for the characterization of weak magnetic NPs.

Vibrating-sample magnetometry (VSM)

This technique measures the magnetic properties of materials based on Faraday’s law of induction. In VSM, the sample is placed in a constant magnetic field in a special holder that vibrates vertically. As the holder starts vibrating, the magnetic moment of the sample creates a magnetic field that changes as function of time. The alternating magnetic field created in the sample induces an electric current that is recorded and used to calculate the magnetic properties of the sample [ 219 , 220 ].

Examples: For the characterization of Fe 2 O 3 NPs produced by Tridax leaf extract, VSM studies revealed that the NPs had a saturation magnetization of 7.78 emu/g, a remnant magnetization of 0.054 emu/g, and a coercivity of − 1.6 G [ 221 ]. In other studies, VSM was used to compare the magnetic properties of iron oxide NPs produced Moringa oleifera with the magnetic properties of the same NPs but coated with chitosan. The researchers found that saturation magnetisation, remnant magnetization, and coercivity have lower values when the NPs are coated with chitosan [ 222 ].

Superconducting quantum interference device (SQUID) magnetometry

This technique measures the magnetic properties of materials based on the Josephson effect. Niobium (Nb) or other metal alloys are used in the device which needs to be operated at temperatures very close to the absolute zero to main superconductivity, where liquid helium is used to maintain the cold environment [ 223 ]. However, other kinds of SQUID also exist where high-temperature superconductors are used [ 224 ]. After reaching superconducting environments, the Josephson junctions contained in the device help to create a supercurrent, which is recorded and used to calculate the magnetic properties of the sample [ 225 ].

Examples: For the characterization of iron oxide NPs produced by Cnidium monnieri seed extract, SQUID magnetometry revealed that the NPs had a saturation magnetization of 54.60 emu/g, a remnant magnetization of 1.15 emu/g, a coercivity of 11 Oe, and a magnetic susceptibility of + 1.69 × 10 –3 emu/ cm 3 ⋅ Oe at room temperatures, indicating the superparamagnetic behaviour of these NPs [ 226 ]. SQUID magnetometry was also used for the characterization of the magnetic properties of zinc incorporated magnetite NPs produced by Geobacter sulfurreducens , showing that the loading of only 5% zinc results in the enhancement of saturation magnetization of the NPs by more than 50% [ 227 ].

Electron spin resonance spectroscopy (ESR)

This technique measures the magnetic properties of materials by characterizing and quantifying the unpaired electrons in the sample. Electrons are charged particles that spin around their axis, which can align in two different orientations (+ ½ and − ½) when the sample is placed in strong magnetic field. These two alignments have different energies due to the Zeeman effect. Since unpaired electrons can change their spins by absorbing or emitting photons, in ESR the sample is irradiated with microwave pulses to excite electron spins until a resonance state is reached [ 228 ]. This technique is also referred to as electron paramagnetic resonance spectroscopy (EPR). It can be used to measure the ferromagnetic and antiferromagnetic properties of NPs [ 229 , 230 ].

Examples: ESR was used to characterize the magnetic properties of iron oxide NPs produced by Ficus carica . The trees naturally produce iron oxide NPs as a defence mechanism when are they are subjected to stress. The researchers found that the magnetic properties of iron oxide NPs produced by the same tree but grown in different environmental conditions have different magnetic properties. In addition, a magnetic anisotropy of the signal was visible as the magnetic properties of these NPs varied strongly at different temperatures [ 231 ]. ESR was also used to characterize the magnetic properties of Se nanomaterials produced by anaerobic granular sludge. The ESR results revealed the presence of Fe(III) atoms incorporated in the Se nanomaterial, which enhanced their overall magnetic properties, giving it ferromagnetic behaviour [ 232 ].

Characterization of thermal properties

Several techniques can be used for the characterization of the thermal properties of NPs, such as melting points, crystallization and structural-phase transition points, heat capacity, thermal conductivity, and thermal and oxidative stability.

Differential scanning calorimetry (DSC)

In this technique the analyte and a well-defined reference sample are put at the same temperature, then, the amount of heat required to increase the temperature of the sample and the reference in measured as a function of temperature. This technique is widely used to measure melting points [ 233 ], crystallization points, structural-phase transition points [ 234 ], latent heat capacity [ 235 ], heat of fusion [ 236 ], and oxidative stability [ 237 ].

Examples: For the characterization of Ag NPs produced by Rhodomyrtus tomentosa leaf extract, DSC showed three exothermic peaks at 44, 159, 243, and an endothermic peak at 441 °C. The first peak (at 44 °C) indicates that at this temperature the NPs face a gradual loss of water from their surface. The second peak (at 159 °C) shows that the thermal decomposition of the sample happens at this temperature. The last temperature (441 °C) indicates the melting temperature for those NPs [ 238 ]. For Ag NPs produced by Parthenium hysterophorus leaf extract, DSC showed that their melting temperature was at 750 °C. The researchers also found that these NPs had completely thermally decomposed and crystallized simultaneously [ 239 ].

Differential thermal analysis (DTA)

This technique is based on heating or cooling a sample and an inert reference under identical conditions, where any temperature difference between the sample and the reference is recorded. This technique is primarily used for the study of phase diagrams and transition temperatures [ 240 ]. However, it is also used to measure the melting points, thermal, and oxidative stability [ 241 , 242 ].

Thermogravimetric analysis (TGA)

This technique measures the change in the mass of a sample as a function of temperature and/or time in a controlled atmosphere [ 243 ]. This technique is mainly used to study the thermal stability of materials [ 244 ], in addition, it is also used to measure structural-phase transition points [ 245 ], thermal activation energies [ 246 ], and oxidative stability [ 247 ]. The resulting thermogram is unique for each compound and therefore can also be used for the determination of material composition [ 248 ]. TGA and DTA are usually combined in the same thermal analyzing instrument, called thermogravimetry/differential thermal analysis (TG/DTA) [ 244 ].

Examples: TG/DTA is a common technique for the characterization of thermal properties of biogenic NPs. For instance, the thermal properties of Ag NPs produced by Daphne mucronate leaf extract were studied in the range between 0–1000 °C where the sample was heated at a rate of 10 °C/min. The researchers found that between 400–500 °C the NPs faced a dominant weight loss, while the weight loss below 400 °C and above 500 °C was negligible. The DTA curve showed an intense exothermic peak in the range between 400–500 °C, this indicates that the crystallization of NPs happens in this temperature interval. Some minor weight loss events were seen below 400 °C, this may be caused by the evaporation of water or the degradation of the organic components [ 249 ]. In another study, the thermal properties of Ag NPs produced by two different plants ( Stereospermum binhchauensis and Jasminum subtriplinerve ) were compared. The researchers found that the major weight loss happens between 220–430 °C, which is attributed to the decomposition of biomolecules from the NP surface [ 250 ]. This shows that Ag NPs produced by these plants have much higher content of biomolecules on their surface than Ag NPs produced by Daphne mucronate. TG/DTA showed that Stereospermum binhchauensis Ag NPs crystallize at 315 °C and Jasminum subtriplinerve Ag NPs at 345 °C, around 100 °C less than Daphne mucronate Ag NPs [ 250 ].

Transient hot wire method (THW)

This method is used for the determination of thermal conductivity based on increasing the temperature of a material by a thin hot wire as a function of time, where the heating wire is located directly in the test sample. The advantage of this method over other thermal conductivity measurement methods is the very short measuring time, this gives high accuracy of thermal conductivity due to the negligible values of convection in such short times [ 251 ]. In this method, the NPs are added to a solution (usually water or ethylene glycol) forming a colloidal dispersion called a nanofluid. Then, the thermal conductivity of the nanofluid is measured and compared to the thermal conductivity of the base fluid, giving a thermal conductivity ratio which is used to evaluate the thermal conductivity of different NPs.

Examples: The thermal conductivity ratios of three different concentrations (0.12, 0.18, and 0.24%) of biogenic SnO 2 NPs produced by Punica granatum seed extract were measured in ethylene glycol at 303 K. The researchers found a linear relationship between NPs concentration and the thermal conductivity. The thermal conductivity enhancement of nanofluid to base fluid was between 6 and 24% [ 252 ]. In another study, the thermal conductivity of Fe 2 O 3 NPs produced by Psidium guajava leaf extract was measured in water and in ethylene glycol. The researchers found that the thermal conductivity enhancement in ethylene glycol was better than in water, the thermal conductivity enhancement for 0.025% Fe 2 O 3 NPs in water was 30% while in ethylene glycol was 34%. Moreover, the linear relationship between NPs concentration and thermal conductivity ratio was found for Fe 2 O 3 NPs in both water and ethylene glycol [ 253 ].

Characterization of mechanical properties

Several methods can be used for the characterization of mechanical properties of NPs, such as tensile and compressive strengths, elasticity, viscoelasticity, hardness, and stiffness.

Tensometery

The machine used for this method is called a universal testing machine (UTM) or a tensometer. It is used to measure the elasticity (elastic modulus), tensile and compressive strengths (Young’s modulus) of materials. In this machine, the sample is placed between grips and an extensometer, where changes in gauge length are recorded as a function of load [ 254 ]. However, other mechanical changes in addition to the change in gauge length are also recorded in this machine, such as the elasticity.

Examples: The mechanical properties of different biogenic NP-containing composites can be measured by this machine. For example, the mechanical properties of orthodontic elastic ligatures containing Ag NPs produced by Heterotheca inuloides were studied by comparing the maximum strength, tension, and displacement of the composite with and without the biogenic NPs. The researchers found that maximum strength, tension, and displacement have improved after the addition of Ag NPs [ 255 ]. Interestingly, the addition of biogenic Ag NPs produced by Diospyros lotus fruit extract to starch and polyvinyl alcohol hydrogel membranes resulted in an adverse effect. The tensile strength and modulus of the hydrogel membranes containing 50 and 100 ppm Ag NPs were much lower than of the neat hydrogel membrane. The researchers attributed this adverse effect to the possibility that the addition of Ag NPs could have resulted in blocking the crosslinking between starch and polyvinyl alcohol, or to the possibility of the formation of breakage points in the polymer matrix due to NPs agglomeration [ 256 ].

Instrumented indentation testing

This method is used to characterize the hardness features of materials by using a well-defined hard indenter tip typically made of diamond. The indenter tip is used to make an indentation in the sample by placing incremental loads on the tip, after which the area of indentation in the sample is measured and used to calculate the hardness features [ 257 ]. Light microscopy, SEM, or ATM technique are usually used to visualize the indentation in the sample. The method is also called micro- or nano-indentation testing.

Examples: This method was used to characterize the mechanical properties of calcite NPs produced by Ophiocoma wendtii brittlestar. The arm plates of this brittlestar are covered by hundreds of nanoscale calcite lenses that focus light onto photoreceptor nerve bundles positioned beneath the brittlestar. The researchers used the nanoindentation method to compare Young’s modulus, hardness and fracture toughness of biogenic calcite with geocalcite. The results showed that the biogenic calcite lenses have higher hardness and fracture toughness compared to geocalcite (more than twofold) [ 258 ]. Bamboo is well known for its high silica content in comparison to other wood species. It produces SiO 2 NPs and deposits it in its epidermis in the form of silica cells. The mechanical properties of silica cells compared to other types of cells of Moso bamboo ( Phyllostachys pubescens ) were studied by instrumented indentation testing. The researchers found that the cell wall of silica cells display higher hardness and elastic recovery compared to fibre and epidermal cells, which is attributed to the presence of biogenic SiO 2 NPs in the silica cells [ 259 ].

Dynamic mechanical analysis (DMA)

This method is used to study the mechanical properties of materials by measuring the strain of a material after applying a stress. This method helps to obtain three different values: storage modulus, loss modulus, and loss tangent. These values are important to give an overview about the stiffness and viscoelasticity behavior of materials [ 260 ].

Examples: The DMA method was used to characterize the mechanical properties of polymethyl methacrylate denture base polymer filled with Ag NPs produced by Boesenbergia rotunda . In this study frequency sweep test was used to determine the viscoelastic behavior of this nanocomposite where the temperature was constant at 37 °C and the frequency was increasing from 0.5 to 100 Hz in tension mode. The researchers found a frequency dependence for storage modulus, loss modulus, and loss tangent for the nanocomposite with various Ag NPs loading concentrations. The frequency dependence of storage modulus, loss modulus, and loss tangent indicates the viscoelastic response of this polymer. However, the results showed that the storage modulus for the nanocomposite is much higher than the loss modulus over the range of frequencies, indicating the elastic dominance of the nanocomposite. Moreover, the researchers found that storage and loss moduli increase with increasing Ag NPs loading concentrations, which is due to the interaction between polymethyl methacrylate and Ag NPs [ 261 ].

In a different study, DMA was used to determine the thermomechanical properties of pol(S-co-BuA) polymer filled with cellulose nanocrystals produced by Posidonia oceanica . In this case, the behaviour of storge modulus and loss tangent were studied as a function of temperature for different cellulose nanocrystals loading concentrations. The results showed that the unloaded polymer behaves like an amorphous polymer, the storage modulus remains constant until the temperature reaches 25 °C then it starts to sharply decrease due to glass–rubber transition. A relaxation process was also evident for the unloader polymer, where the loss tangent reaches its maximum at 35 °C then it starts to fall. The addition of cellulose nanocrystals to the polymer positively enhanced both effects. The dramatic drop of storage modulus at 25 °C was less for the nanocomposite, where the drop for the polymer loaded with 15% cellulose nanocrystals was almost cancelled. Similar positive enhancement was found for loss tangent. These enhancements could be attributed to the mechanical coupling effect, in which the NPs connect and form a stiff continuous network linked through hydrogen bonding [ 262 ].

Applications of NPs

NPs, due to their above-mentioned unique or enhanced physicochemical properties, are used in a wide range of applications in different fields. In addition, several potential applications are in research and development. Here we present some examples of these applications.

Applications in medicine and pharma

Metallic and semiconductor NPs have huge potential for cancer diagnosis and therapy based on their enhanced light scattering and absorption properties due to LSPR effect. For instance, Au NPs efficiently absorb light and convert it into localized heat, which can be exploited for selective photothermal therapy of cancer (cancer cell death by heat generated in tumor tissue) [ 263 , 264 ]. In addition, the unique optical properties of Au NPs make them a great candidate for the photodynamic therapy of cancer (the use of a drug that is activated by light to kill cancer cells) [ 265 ]. Gd based NPs have also shown great abilities in tumor growth inhibition [ 266 ], metastasis inhibition [ 267 ], and tumor-specific magnetic resonance contrast enhancement [ 268 ]. Targeted drug delivery is also an important potential application of NPs. ZnO and Fe 3 O 4 NPs were efficiently used for targeted drug delivery and selective destruction of tumor cells [ 269 , 270 , 271 ].

Moreover, NPs have been successfully used in different medical applications such as cellular imaging [ 272 ], or in biosensors for DNA, carbohydrates, proteins, and heavy metal ions [ 273 , 274 ], determination of blood glucose levels [ 275 ], and for medical diagnostics to detect bacteria [ 276 ] and viruses [ 277 ]. For instance, Au NPs were conjugated with SARS-CoV-2 antigens to rapidly detect the presence of SARS-CoV-2 IgM/IgA antibodies in blood samples within 10–15 min [ 278 ], At the same time, due to their antimicrobial and antibacterial activities, NPs such as TiO 2 , ZnO, CuO, and BiVO 4 are being increasing used in various medical products such as catheters [ 279 , 280 ].

Applications in electronics

NPs, due to their novel electronic and optical properties, have a wide range of potential applications in imaging techniques and electronics. For instance, Gd-based NPs can improve the imaging quality and the contrast agent administration dose of magnetic resonance imaging (MRI). The use of Gd 2 O 3 NPs as a contrasting agent was found to be more efficient than the commonly used agent (Gd-DOTA) at the same concentration [ 281 ]. At the same time, GdPO 4 NPs were successfully used for tumor detection using MRI in 1/10 of the dose typically used with Gd-DTPA agent [ 282 ]. Interestingly, NPs also offer the ability to image and track a single molecule, which can reveal important information about cellular processes such as membrane protein organization and interaction with other proteins. For example, Eu 3+ -doped oxide NPs were used to track a single toxin receptor with a localization precision of 30 nm [ 283 ].

Regarding applications in batteries, an important component in lithium-ion batteries is the separators. Their main function is to prevent the physical contact of anode and cathode, and to provide channels for the transport of ions. The commonly used commercial material in battery separators, a polyolefin microporous membrane, suffers from poor electrolyte uptake and poor thermal stability [ 284 ]. Due to the aerogel structure of some NPs (such as ZnO NPs), they are an ideal choice for separator plates in batteries [ 284 ]. This makes the batteries store a significantly higher amount of energy compared to traditional batteries. For lithium-air batteries, using Pt-Au bimetallic NPs strongly enhances oxygen reduction and oxygen evolution reactions [ 285 ]. Moreover, batteries made of nanocrystalline Ni and metal hydrides last longer and require less charging [ 23 ]. In addition to battery applications, several NPs such as CdS and ZnSe are also used in light-emitting diodes (LED) of modern displays to get higher brightness and bigger screens [ 23 , 286 ]. Other NPs such as CdTe NPs are also used in liquid crystal displays (LCDs) [ 287 ]. The addition of a NP layer to LED and LCD enables them to generate more light using the same amount of energy and enhances their lifetime.

Applications in agriculture

NPs have potential to benefit the agriculture field by providing new solutions to current agricultural and environmental problems [ 288 ]. NPs are mainly used in two forms in agriculture, as nanofertilizers and nanopesticides. Chemical fertilizers have poor efficiency due to leaching and volatilization. In these cases, the farmers usually react by using excessive amounts of fertilizers, which increases crops productivity but has an environmental cost [ 288 ]. In contrast, nanofertilizers are compounds that are applied in smaller amounts than regular chemical fertilizers but yet have better efficiencies [ 289 ]. The difference in efficiency comes from the fact that they are able to release the nutrients just when and where they are required by the plants. In that way, they limit the conversion of excess amounts of fertilizer to gaseous forms or from leaking into the ground water [ 290 ]. Several NPs have been employed in the development of fertilizers, including SiO 2 , ZnO, CuO, Fe, and Mg NPs [ 291 , 292 , 293 ]. These nanofertilizers provide the plants with increased nitrogen fixation, improved seed germination, amelioration to drought stress, increased seed weight, and increased photosynthesis ability [ 291 , 292 , 293 ]. The large surface area and small size of these NPs are the main reasons for the better efficiencies of nanofertilizers over conventional fertilizers [ 294 ].

Several NPs have proven antimicrobial, insecticidal, and nematicidal activities, which makes them a promising alternative to chemical pesticides and a potentially cheaper alternative to biopesticides [ 294 ]. For instance, the photocatalytic activity of TiO 2 NPs gives them a potent antimicrobial activity against Xanthomonas perforans , the causing agent of tomato spot disease [ 295 ]. CuO NPs show insecticidal activity against Spodoptera littoralis , known as African cotton leafworm [ 296 ]. Ag NPs show nematicidal activity against Meloidogyne spp. , root-knot nematodes [ 297 ].

Applications in the food industry

NPs, despite toxological concerns, have impactful applications in several food industry-related process such as food production, preservation, and packaging. TiO 2 NPs are a major promising player in this industry. Their photocatalytic antimicrobial activity makes them an interesting material for food packaging [ 298 ]. In addition, they are also used in sensors to detect volatile organic compounds [ 299 ]. Ag NPs are also promising in food packaging due to their antimicrobial activity. They play an important role in reducing the risk of pathogens and extending food shelf-life [ 294 ]. The efficiency of doping Ag and ZnO NPs to degradable and non-degradable packaging materials for meat, bread, fruit, and dairy products was tested against several yeast, molds, aerobic, and anaerobic bacteria [ 300 ]. For instance, polyvinyl chloride doped with Ag NPs was evaluated for packing minced meet at refrigerator temperature (4 °C); the results showed that Ag NPs significantly helped to slow down bacterial growth, increasing the shelf-life of minced meet from 2 to 7 days [ 301 ].

Effects of NPs on biological systems

Although the use of NPs is exponentially growing, their possible toxicological and hazardous impacts to human health and environment cannot be ignored. NPs may get released to the environment during production stages, usage, recycling, or disposal. These NPs may persist in air, soil, water, or biological systems [ 302 ]. NPs can enter the human or animal body though the skin, orally, or via the respiratory tract, and afterwards move to other parts of the body. The exposure to NPs was found to activate proinflammatory cytokines and chemokines with recruitment of inflammatory cells, which impacts the immune system homeostasis and can lead to autoimmune, allergic, or neoplastic diseases [ 302 ]. Moreover, the exposure to ultrafine particles can cause pulmonary, cardiac, and central nervous system diseases [ 303 , 304 , 305 ]. Similarly, NPs can enter plants cells and cause harmful effects [ 306 ]. For instance, the exposure of ZnO and Al NPs was found to cause root growth inhibition in plants [ 307 , 308 ].

Nanoscience and nanotechnology are inherently transdisciplinary fields of science. With new bio-based approaches, there is a need for biologists to understand not only the basic principles of nanoscience, but also the technologies and methods traditionally employed to characterize nanomaterials. We hope that this review can help to inspire new collaborations across different scientific disciplines, by helping biologists to identify the best technologies—and partners—to characterize their nanomaterials. At the same time, we recommend to take potential biological risks of these new materials into careful consideration already during the planning phase of such experiments.

Availability of data and materials

Not applicable.

https://www.etymonline.com/word/nano .

[SOURCE: ISO/TS 80,004‑2:2015, 4.4].

Abbreviations

Atomic force microscopy

Brunauer–Emmett–Teller

Barrett–Joyner–Halenda

Cyclic voltammetry

Dynamic light scattering

Derjaguin–Landau–Verwey–Overbeek

Dynamic mechanical analysis

Derjaguin–Muller–Toporov

UV–vis diffuse reflectance spectroscopy

Differential scanning calorimetry

Differential thermal analysis

Energy-dispersive X-ray spectroscopy

Electron microscopy

Electron paramagnetic resonance spectroscopy

Electron spin resonance spectroscopy

Fourier-transform infrared spectroscopy

High-angle annular dark-field imaging

International Organization for Standardization

Johnson–Kendall–Roberts

Liquid crystal display

Light-emitting diode

Localized surface plasmon resonance

Magnetic force microscopy

Magnetic resonance imaging

Nanoparticles

Nanoparticle tracking analysis

Photoluminescence spectroscopy

Critical radius

Threshold radius for superparamagnetism

Selected area electron diffraction

Scanning electron microscopy

Surface-enhanced Raman spectroscopy

Surface plasmon resonance

Superconducting quantum interference device

Scanning transmission electron microscopy

Scanning tunneling microscopy

Transmission electron microscopy

Thermogravimetry/differential thermal analysis

Thermogravimetric analysis

Transient hot wire

Universal testing machine

Ultraviolet

Ultraviolet–visible spectroscopy

Vibrating-sample magnetometry

X-ray photoelectron spectroscopy

X-ray diffraction analysis

Buzea C, Pacheco II, Robbie K. Nanomaterials and nanoparticles: sources and toxicity. Biointerphases. 2007;2(4):MR17–71.

Article   PubMed   Google Scholar  

Mulvaney P. Nanoscience vs nanotechnology—defining the field. ACS Nano. 2015. https://doi.org/10.1021/acsnano.5b01418 .

Hasan S. A review on nanoparticles: their synthesis and types. Res J Recent Sci. 2015;2277:2502.

Google Scholar  

Feynman RP. Plenty of room at the bottom. In: APS annual meeting. 1959.

Tolochko NK. History of nanotechnology (Chapter 1). In: Kharkin V, Bai C, Kapitza S, Awadelkarim OO, editors. Nanoscience and nanotechnologies (vol. 1). ISBN 978-1-78021-531-0. https://www.eolss.net/ebooklib/bookinfo/nanoscience-nanotechnologies.aspx

Walter P, Welcomme E, Hallégot P, Zaluzec NJ, Deeb C, Castaing J, et al. Early use of PbS nanotechnology for an ancient hair dyeing formula. Nano Lett. 2006;6(10):2215–9.

Article   CAS   PubMed   Google Scholar  

Barber DJ, Freestone IC. An investigation of the origin of the colour of the Lycurgus Cup by analytical transmission electron microscopy. Archaeometry. 1990;32(1):33–45.

Article   Google Scholar  

Atwater HA. The promise of plasmonics. Sci Am. 2007;296(4):56–63.

Brill RH, Cahill ND. A red opaque glass from Sardis and some thoughts on red opaques in general. J Glass Stud. 1988;30:16–27. http://www.jstor.org/stable/24190804

Sharon M. History of nanotechnology: from prehistoric to modern times. New Jersey: Wiley; 2019.

Book   Google Scholar  

Bratovcic A. Different applications of nanomaterials and their impact on the environment. Int J Mater Sci Eng. 2019;5:1–7.

Gajanan K, Tijare SN. Applications of nanomaterials. Mater Today Proc. 2018;5(1):1093–6.

Article   CAS   Google Scholar  

Khot LR, Sankaran S, Maja JM, Ehsani R, Schuster EW. Applications of nanomaterials in agricultural production and crop protection: a review. Crop Prot. 2012;35:64–70.

Roduner E. Size matters: why nanomaterials are different. Chem Soc Rev. 2006;35(7):583–92.

Lines MG. Nanomaterials for practical functional uses. J Alloys Compd. 2008;449(1–2):242–5.

Gade A, Ingle A, Whiteley C, Rai M. Mycogenic metal nanoparticles: progress and applications. Biotechnol Lett. 2010;32(5):593–600.

Ikhmayies SJ. Characterization of nanomaterials. JOM. 2014;66(1):28–9.

Ashraf MA, Peng W, Zare Y, Rhee KY. Effects of size and aggregation/agglomeration of nanoparticles on the interfacial/interphase properties and tensile strength of polymer nanocomposites. Nanoscale Res Lett. 2018;13(1):1–7.

Suttiponparnit K, Jiang J, Sahu M, Suvachittanont S, Charinpanitkul T, Biswas P. Role of surface area, primary particle size, and crystal phase on titanium dioxide nanoparticle dispersion properties. Nanoscale Res Lett. 2011;6(1):1–8.

Fubini B, Ghiazza M, Fenoglio I. Physico-chemical features of engineered nanoparticles relevant to their toxicity. Nanotoxicology. 2010;4(4):347–63.

Geoffrion LD, Guisbiers G. Quantum confinement: size on the grill! J Phys Chem Solids. 2020;140: 109320.

Kolahalam LA, Viswanath IVK, Diwakar BS, Govindh B, Reddy V, Murthy YLN. Review on nanomaterials: synthesis and applications. Mater Today Proc. 2019;18:2182–90.

Ealia SAM, Saravanakumar MP. A review on the classification, characterisation, synthesis of nanoparticles and their application. In: IOP Conference Series: Materials Science and Engineering. IOP Publishing; 2017. p. 32019.

Machado S, Pacheco JG, Nouws HPA, Albergaria JT, Delerue-Matos C. Characterization of green zero-valent iron nanoparticles produced with tree leaf extracts. Sci Total Environ. 2015;533:76–81.

Khan I, Saeed K, Khan I. Nanoparticles: properties, applications and toxicities. Arab J Chem. 2019;12(7):908–31.

Pan K, Zhong Q. Organic nanoparticles in foods: fabrication, characterization, and utilization. Annu Rev Food Sci Technol. 2016;7:245–66.

Ng KK, Zheng G. Molecular interactions in organic nanoparticles for phototheranostic applications. Chem Rev. 2015;115(19):11012–42.

Gujrati M, Malamas A, Shin T, Jin E, Sun Y, Lu Z-R. Multifunctional cationic lipid-based nanoparticles facilitate endosomal escape and reduction-triggered cytosolic siRNA release. Mol Pharm. 2014;11(8):2734–44.

Article   CAS   PubMed   PubMed Central   Google Scholar  

Long CM, Nascarella MA, Valberg PA. Carbon black vs black carbon and other airborne materials containing elemental carbon: physical and chemical distinctions. Environ Pollut. 2013;181:271–86.

Dresselhaus MS, Dresselhaus G, Eklund PC. Fullerenes. J Mater Res. 1993;8(8):2054–97.

Yuan X, Zhang X, Sun L, Wei Y, Wei X. Cellular toxicity and immunological effects of carbon-based nanomaterials. Part Fibre Toxicol. 2019;16(1):1–27.

Lu K-Q, Quan Q, Zhang N, Xu Y-J. Multifarious roles of carbon quantum dots in heterogeneous photocatalysis. J Energy Chem. 2016;25(6):927–35.

Mauter MS, Elimelech M. Environmental applications of carbon-based nanomaterials. Environ Sci Technol. 2008;42(16):5843–59.

Oh W-K, Yoon H, Jang J. Size control of magnetic carbon nanoparticles for drug delivery. Biomaterials. 2010;31(6):1342–8.

Liu M, Zhao F, Zhu D, Duan H, Lv Y, Li L, et al. Ultramicroporous carbon nanoparticles derived from metal–organic framework nanoparticles for high-performance supercapacitors. Mater Chem Phys. 2018;211:234–41.

Chandra S, Das P, Bag S, Laha D, Pramanik P. Synthesis, functionalization and bioimaging applications of highly fluorescent carbon nanoparticles. Nanoscale. 2011;3(4):1533–40.

Mochalin VN, Shenderova O, Ho D, Gogotsi Y. The properties and applications of nanodiamonds. Nat Nanotechnol. 2012;7(1):11–23.

Ahlawat J, Asil SM, Barroso GG, Nurunnabi M, Narayan M. Application of carbon nano onions in the biomedical field: recent advances and challenges. Biomater Sci. 2021. https://doi.org/10.1039/D0BM01476A .

Toshima N, Yonezawa T. Bimetallic nanoparticles—novel materials for chemical and physical applications. New J Chem. 1998;22(11):1179–201.

Nascimento MA, Cruz JC, Rodrigues GD, de Oliveira AF, Lopes RP. Synthesis of polymetallic nanoparticles from spent lithium-ion batteries and application in the removal of reactive blue 4 dye. J Clean Prod. 2018;202:264–72.

Mody VV, Siwale R, Singh A, Mody HR. Introduction to metallic nanoparticles. J Pharm Bioallied Sci. 2010;2(4):282.

Fedlheim DL, Foss CA. Metal nanoparticles: synthesis, characterization, and applications. Boca Raton: CRC Press; 2001.

Dreaden EC, Alkilany AM, Huang X, Murphy CJ, El-Sayed MA. The golden age: gold nanoparticles for biomedicine. Chem Soc Rev. 2012;41(7):2740–79.

Gupta SM, Tripathi M. An overview of commonly used semiconductor nanoparticles in photocatalysis. High Energy Chem. 2012;46(1):1–9.

Sun S, Murray CB, Weller D, Folks L, Moser A. Monodisperse FePt nanoparticles and ferromagnetic FePt nanocrystal superlattices. Science (80-). 2000;287(5460):1989–92.

Thomas S, Kumar Mishra P, Talegaonkar S. Ceramic nanoparticles: fabrication methods and applications in drug delivery. Curr Pharm Des. 2015;21(42):6165–88.

Moreno-Vega A-I, Gomez-Quintero T, Nunez-Anita R-E, Acosta-Torres L-S, Castaño V. Polymeric and ceramic nanoparticles in biomedical applications. J Nanotechnol. 2012. https://doi.org/10.1155/2012/936041 .

D’Amato R, Falconieri M, Gagliardi S, Popovici E, Serra E, Terranova G, et al. Synthesis of ceramic nanoparticles by laser pyrolysis: from research to applications. J Anal Appl Pyrolysis. 2013;104:461–9.

Wu Q, Miao W, Gao H, Hui D. Mechanical properties of nanomaterials: a review. Nanotechnol Rev. 2020;9(1):259–73.

Pithawalla YB, El-Shall MS, Deevi SC, Ström V, Rao KV. Synthesis of magnetic intermetallic FeAl nanoparticles from a non-magnetic bulk alloy. J Phys Chem B. 2001;105(11):2085–90.

Keesom WH. On the deduction of the equation of state from Boltzmann’s entropy principle’. KNAW Proc. 1912;15:240–56.

Debye P. Molecular forces and their electrical interpretation. Phys Zeitschrift. 1921;22:302–8.

CAS   Google Scholar  

London F. The general theory of molecular forces. Trans Faraday Soc. 1937;33:8b–26.

Guo D, Xie G, Luo J. Mechanical properties of nanoparticles: basics and applications. J Phys D Appl Phys. 2013;47(1):13001.

Missana T, Adell A. On the applicability of DLVO theory to the prediction of clay colloids stability. J Colloid Interface Sci. 2000;230(1):150–6.

Brant J, Lecoanet H, Wiesner MR. Aggregation and deposition characteristics of fullerene nanoparticles in aqueous systems. J Nanoparticle Res. 2005;7(4):545–53.

Tan S, Sherman RL, Ford WT. Nanoscale compression of polymer microspheres by atomic force microscopy. Langmuir. 2004;20(17):7015–20.

Armini S, Vakarelski IU, Whelan CM, Maex K, Higashitani K. nanoscale indentation of polymer and composite polymer−silica core−shell submicrometer particles by atomic force microscopy. Langmuir. 2007;23(4):2007–14.

Savage T, Rao AM. Thermal properties of nanomaterials and nanocomposites. In: Thermal conductivity. Springer; 2004. p. 261–84.

Andrievski RA. Review of thermal stability of nanomaterials. J Mater Sci. 2014;49(4):1449–60.

Qiu L, Zhu N, Feng Y, Michaelides EE, Żyła G, Jing D, et al. A review of recent advances in thermophysical properties at the nanoscale: from solid state to colloids. Phys Rep. 2020;843:1–81.

Shima PD, Philip J, Raj B. Role of microconvection induced by Brownian motion of nanoparticles in the enhanced thermal conductivity of stable nanofluids. Appl Phys Lett. 2009;94(22): 223101.

Syam Sundar L, Sharma KV. Thermal conductivity enhancement of nanoparticles in distilled water. Int J Nanoparticles. 2008;1(1):66–77.

Eastman JA, Choi SUS, Li S, Yu W, Thompson LJ. Anomalously increased effective thermal conductivities of ethylene glycol-based nanofluids containing copper nanoparticles. Appl Phys Lett. 2001;78(6):718–20.

Zebarjadi M, Esfarjani K, Shakouri A, Bahk J-H, Bian Z, Zeng G, et al. Effect of nanoparticle scattering on thermoelectric power factor. Appl Phys Lett. 2009;94(20): 202105.

Zeng G, Zide JMO, Kim W, Bowers JE, Gossard AC, Bian Z, et al. Cross-plane Seebeck coefficient of Er As: In Ga As/In Ga Al As superlattices. J Appl Phys. 2007;101(3):34502.

Kim W, Singer SL, Majumdar A, Vashaee D, Bian Z, Shakouri A, et al. Cross-plane lattice and electronic thermal conductivities of Er As: In Ga As∕ In Ga Al As superlattices. Appl Phys Lett. 2006;88(24):242107.

Likhachev VN, Vinogradov GA, Alymov MI. Anomalous heat capacity of nanoparticles. Phys Lett A. 2006;357(3):236–9.

Wang L, Tan Z, Meng S, Liang D, Li G. Enhancement of molar heat capacity of nanostructured Al 2 O 3 . J Nanoparticle Res. 2001;3(5):483–7.

Wang L, Tan Z, Meng S, Druzhinina A, Varushchenko RA, Li G. Heat capacity enhancement and thermodynamic properties of nanostructured amorphous SiO 2 . J Non Cryst Solids. 2001;296(1–2):139–42.

Borel J-P. Thermodynamical size effect and the structure of metallic clusters. Surf Sci. 1981;106(1–3):1–9.

Gülseren O, Ercolessi F, Tosatti E. Premelting of thin wires. Phys Rev B. 1995;51(11):7377.

Shim J-H, Lee B-J, Cho YW. Thermal stability of unsupported gold nanoparticle: a molecular dynamics study. Surf Sci. 2002;512(3):262–8.

Naitabdi A, Ono LK, Behafarid F, Cuenya BR. Thermal stability and segregation processes in self-assembled size-selected Au x Fe1-x nanoparticles deposited on TiO 2 (110): composition effects. J Phys Chem C. 2009;113(4):1433–46.

Mottet C, Rossi G, Baletto F, Ferrando R. Single impurity effect on the melting of nanoclusters. Phys Rev Lett. 2005;95(3):35501.

Cuenya BR. Synthesis and catalytic properties of metal nanoparticles: size, shape, support, composition, and oxidation state effects. Thin Solid Films. 2010;518(12):3127–50.

Nealon GL, Donnio B, Greget R, Kappler J-P, Terazzi E, Gallani J-L. Magnetism in gold nanoparticles. Nanoscale. 2012;4(17):5244–58.

Matthias BT, Clogston AM, Williams HJ, Corenzwit E, Sherwood RC. Ferromagnetism in solid solutions of Scandium and Indium. Phys Rev Lett. 1961;7(1):7.

Matthias BT, Bozorth RM. Ferromagnetism of a zirconium–zinc compound. Phys Rev. 1958;109(2):604.

Acker F, Fisk Z, Smith JL, Huang CY. Enhanced paramagnetism of TiBe2 and ferromagnetic transitions in TiBe2-xCux. J Magn Magn Mater. 1981;22(3):250–6.

Hori H, Teranishi T, Nakae Y, Seino Y, Miyake M, Yamada S. Anomalous magnetic polarization effect of Pd and Au nano-particles. Phys Lett A. 1999;263(4–6):406–10.

McCurrie RA. Ferromagnetic materials: structure and properties. Cambridge: Academic Press; 1994.

Edelstein AS, Cammaratra RC. Nanomaterials: synthesis, properties and applications. Boca Raton: CRC Press; 1998.

Jun Y, Seo J, Cheon J. Nanoscaling laws of magnetic nanoparticles and their applicabilities in biomedical sciences. Acc Chem Res. 2008;41(2):179–89.

Skumryev V, Stoyanov S, Zhang Y, Hadjipanayis G, Givord D, Nogués J. Beating the superparamagnetic limit with exchange bias. Nature. 2003;423(6942):850–3.

Kolhatkar AG, Jamison AC, Litvinov D, Willson RC, Lee TR. Tuning the magnetic properties of nanoparticles. Int J Mol Sci. 2013;14(8):15977–6009.

Hu M, Butt H-J, Landfester K, Bannwarth MB, Wooh S, Thérien-Aubin H. Shaping the assembly of superparamagnetic nanoparticles. ACS Nano. 2019;13(3):3015–22.

Marghussian V, Marghussian V. Nano-glass ceramics. Amsterdam: Elsevier; 2015.

Kalubowilage M, Janik K, Bossmann SH. Magnetic nanomaterials for magnetically-aided drug delivery and hyperthermia. Appl Sci. 2019;9(14):2927.

Podaru G, Chikan V. Magnetism in nanomaterials: heat and force from colloidal magnetic particles. 2017;

Song Q, Zhang ZJ. Shape control and associated magnetic properties of spinel cobalt ferrite nanocrystals. J Am Chem Soc. 2004;126(19):6164–8.

Salazar-Alvarez G, Qin J, Sepelak V, Bergmann I, Vasilakaki M, Trohidou KN, et al. Cubic versus spherical magnetic nanoparticles: the role of surface anisotropy. J Am Chem Soc. 2008;130(40):13234–9.

Zhen G, Muir BW, Moffat BA, Harbour P, Murray KS, Moubaraki B, et al. Comparative study of the magnetic behavior of spherical and cubic superparamagnetic iron oxide nanoparticles. J Phys Chem C. 2011;115(2):327–34.

Lee W, Kim MG, Choi J, Park J-I, Ko SJ, Oh SJ, et al. Redox-transmetalation process as a generalized synthetic strategy for core-shell magnetic nanoparticles. J Am Chem Soc. 2005;127(46):16090–7.

Park J-I, Cheon J. Synthesis of “solid solution” and “core-shell” type cobalt–platinum magnetic nanoparticles via transmetalation reactions. J Am Chem Soc. 2001;123(24):5743–6.

Lee J-H, Huh Y-M, Jun Y, Seo J, Jang J, Song H-T, et al. Artificially engineered magnetic nanoparticles for ultra-sensitive molecular imaging. Nat Med. 2007;13(1):95–9.

Kumbhakar P, Ray SS, Stepanov AL. Optical properties of nanoparticles and nanocomposites. Hindawi; 2014.

Khlebtsov NG, Dykman LA. Optical properties and biomedical applications of plasmonic nanoparticles. J Quant Spectrosc Radiat Transf. 2010;111(1):1–35.

Kelly KL, Coronado E, Zhao LL, Schatz GC. The optical properties of metal nanoparticles: the influence of size, shape, and dielectric environment. Washington: ACS Publications; 2003.

Kreibig U, Vollmer M. Theoretical considerations. In: Optical properties of metal clusters. Springer; 1995. p. 13–201.

Duval Malinsky M, Kelly KL, Schatz GC, Van Duyne RP. Nanosphere lithography: effect of substrate on the localized surface plasmon resonance spectrum of silver nanoparticles. J Phys Chem B. 2001;105(12):2343–50.

Jensen TR, Duval ML, Kelly KL, Lazarides AA, Schatz GC, Van Duyne RP. Nanosphere lithography: effect of the external dielectric medium on the surface plasmon resonance spectrum of a periodic array of silver nanoparticles. J Phys Chem B. 1999;103(45):9846–53.

Rajan AR, Vilas V, Rajan A, John A, Philip D. Synthesis of nanostructured CeO2 by chemical and biogenic methods: optical properties and bioactivity. Ceram Int. 2020;46(9):14048–55.

Fu L, Fu Z. Plectranthus amboinicus leaf extract-assisted biosynthesis of ZnO nanoparticles and their photocatalytic activity. Ceram Int. 2015;41(2):2492–6.

Cuenya BR, Baeck S-H, Jaramillo TF, McFarland EW. Size-and support-dependent electronic and catalytic properties of Au0/Au3+ nanoparticles synthesized from block copolymer micelles. J Am Chem Soc. 2003;125(42):12928–34.

Shaikhutdinov SK, Meyer R, Naschitzki M, Bäumer M, Freund H-J. Size and support effects for CO adsorption on gold model catalysts. Catal Lett. 2003;86(4):211–9.

Lemire C, Meyer R, Shaikhutdinov S, Freund H. Do quantum size effects control CO adsorption on gold nanoparticles? Angew Chem Int Ed. 2004;43(1):118–21.

Ono LK, Sudfeld D, Cuenya BR. In situ gas-phase catalytic properties of TiC-supported size-selected gold nanoparticles synthesized by diblock copolymer encapsulation. Surf Sci. 2006;600(23):5041–50.

Lu Y, Chen W. Size effect of silver nanoclusters on their catalytic activity for oxygen electro-reduction. J Power Sources. 2012;197:107–10.

Shao M, Peles A, Shoemaker K. Electrocatalysis on platinum nanoparticles: particle size effect on oxygen reduction reaction activity. Nano Lett. 2011;11(9):3714–9.

Valden M, Lai X, Goodman DW. Onset of catalytic activity of gold clusters on titania with the appearance of nonmetallic properties. Science (80-). 1998;281(5383):1647–50.

Zhang P, Sham TK. X-ray studies of the structure and electronic behavior of alkanethiolate-capped gold nanoparticles: the interplay of size and surface effects. Phys Rev Lett. 2003;90(24): 245502.

Haruta M. Nanoparticulate gold catalysts for low-temperature CO oxidation. ChemInform. 2004. https://doi.org/10.1002/chin.200448226 .

Xu R, Wang D, Zhang J, Li Y. Shape-dependent catalytic activity of silver nanoparticles for the oxidation of styrene. Chem Asian J. 2006;1(6):888–93.

Henry CR. Morphology of supported nanoparticles. Prog Surf Sci. 2005;80(3–4):92–116.

Humbert MP, Murillo LE, Chen JG. Rational design of platinum-based bimetallic catalysts with enhanced hydrogenation activity. ChemPhysChem. 2008;9(9):1262–4.

Toda T, Igarashi H, Uchida H, Watanabe M. Enhancement of the electroreduction of oxygen on Pt alloys with Fe, Ni, and Co. J Electrochem Soc. 1999;146(10):3750.

Igarashi H, Fujino T, Zhu Y, Uchida H, Watanabe M. CO tolerance of Pt alloy electrocatalysts for polymer electrolyte fuel cells and the detoxification mechanism. Phys Chem Chem Phys. 2001;3(3):306–14.

Croy JR, Mostafa S, Hickman L, Heinrich H, Cuenya BR. Bimetallic Pt-Metal catalysts for the decomposition of methanol: effect of secondary metal on the oxidation state, activity, and selectivity of Pt. Appl Catal A Gen. 2008;350(2):207–16.

Liu P, Nørskov JK. Ligand and ensemble effects in adsorption on alloy surfaces. Phys Chem Chem Phys. 2001;3(17):3814–8.

Carlsson AF, Naschitzki M, Bäumer M, Freund H-J. The structure and reactivity of Al 2 O 3 -supported cobalt–palladium particles: a CO-TPD, STM, and XPS study. J Phys Chem B. 2003;107(3):778–85.

Besenbacher F, Chorkendorff I, Clausen BS, Hammer B, Molenbroek AM, Nørskov JK, et al. Design of a surface alloy catalyst for steam reforming. Science. 1998;279(5358):1913–5.

Ono LK, Roldan-Cuenya B. Effect of interparticle interaction on the low temperature oxidation of CO over size-selected Au nanocatalysts supported on ultrathin TiC films. Catal Lett. 2007;113(3):86–94.

Knapp M, Crihan D, Seitsonen AP, Over H. Hydrogen transfer reaction on the surface of an oxide catalyst. J Am Chem Soc. 2005;127(10):3236–7.

Hendriksen BLM, Frenken JWM. CO oxidation on Pt (110): scanning tunneling microscopy inside a high-pressure flow reactor. Phys Rev Lett. 2002;89(4):46101.

Gong X-Q, Raval R, Hu P. General insight into CO oxidation: a density functional theory study of the reaction mechanism on platinum oxides. Phys Rev Lett. 2004;93(10): 106104.

Gong X-Q, Liu Z-P, Raval R, Hu P. A systematic study of CO oxidation on metals and metal oxides: density functional theory calculations. J Am Chem Soc. 2004;126(1):8–9.

Over H, Seitsonen AP. Oxidation of metal surfaces. Science (80-). 2002;297(5589):2003–5.

Yoon B, Häkkinen H, Landman U, Wörz AS, Antonietti J-M, Abbet S, et al. Charging effects on bonding and catalyzed oxidation of CO on Au8 clusters on MgO. Science (80-). 2005;307(5708):403–7.

Laursen S, Linic S. Oxidation catalysis by oxide-supported Au nanostructures: the role of supports and the effect of external conditions. Phys Rev Lett. 2006;97(2):26101.

Rodriguez JA, Wang X, Liu P, Wen W, Hanson JC, Hrbek J, et al. Gold nanoparticles on ceria: importance of O vacancies in the activation of gold. Top Catal. 2007;44(1–2):73–81.

Yan W, Chen B, Mahurin SM, Dai S, Overbury SH. Brookite-supported highly stable gold catalytic system for CO oxidation. Chem Commun. 2004;17:1918–9.

Rodriguez JA, Liu P, Viñes F, Illas F, Takahashi Y, Nakamura K. Dissociation of SO2 on Au/TiC (001): effects of Au–C interactions and charge polarization. Angew Chemie. 2008;120(35):6787–91.

Vladár AE, Hodoroaba V-D. Characterization of nanoparticles by scanning electron microscopy. In: Characterization of nanoparticles. Elsevier; 2020. p. 7–27.

Kano S, Tada T, Majima Y. Nanoparticle characterization based on STM and STS. Chem Soc Rev. 2015;44(4):970–87.

Kumar A, Dixit CK. Methods for characterization of nanoparticles. In: Advances in nanomedicine for the delivery of therapeutic nucleic acids. Elsevier; 2017. p. 43–58.

Kouvaris P, Delimitis A, Zaspalis V, Papadopoulos D, Tsipas SA, Michailidis N. Green synthesis and characterization of silver nanoparticles produced using Arbutus unedo leaf extract. Mater Lett. 2012;76:18–20.

Song JY, Kim BS. Rapid biological synthesis of silver nanoparticles using plant leaf extracts. Bioprocess Biosyst Eng. 2009;32(1):79–84.

Hungund BS, Dhulappanavar GR, Ayachit NH. Comparative evaluation of antibacterial activity of silver nanoparticles biosynthesized using fruit juices. J Nanomed Nanotechnol. 2015;6(2):1.

Li Z, Wang Y, Shen J, Liu W, Sun X. The measurement system of nanoparticle size distribution from dynamic light scattering data. Opt Lasers Eng. 2014;56:94–8.

Raval N, Maheshwari R, Kalyane D, Youngren-Ortiz SR, Chougule MB, Tekade RK. Importance of physicochemical characterization of nanoparticles in pharmaceutical product development. In: Basic fundamentals of drug delivery. Elsevier; 2019. p. 369–400.

Tripathi RM, Gupta RK, Shrivastav A, Singh MP, Shrivastav BR, Singh P. Trichoderma koningii assisted biogenic synthesis of silver nanoparticles and evaluation of their antibacterial activity. Adv Nat Sci Nanosci Nanotechnol. 2013;4(3):35005.

Roy K, Sarkar CK, Ghosh CK. Photocatalytic activity of biogenic silver nanoparticles synthesized using potato ( Solanum tuberosum ) infusion. Spectrochim Acta Part A Mol Biomol Spectrosc. 2015;146:286–91.

Soldatova AV, Balakrishnan G, Oyerinde OF, Romano CA, Tebo BM, Spiro TG. Biogenic and synthetic MnO 2 nanoparticles: size and growth probed with absorption and Raman spectroscopies and dynamic light scattering. Environ Sci Technol. 2019;53(8):4185–97.

Filipe V, Hawe A, Jiskoot W. Critical evaluation of nanoparticle tracking analysis (NTA) by NanoSight for the measurement of nanoparticles and protein aggregates. Pharm Res. 2010;27(5):796–810.

Gross J, Sayle S, Karow AR, Bakowsky U, Garidel P. Nanoparticle tracking analysis of particle size and concentration detection in suspensions of polymer and protein samples: influence of experimental and data evaluation parameters. Eur J Pharm Biopharm. 2016;104:30–41.

Rodrigues MC, Rolim WR, Viana MM, Souza TR, Gonçalves F, Tanaka CJ, et al. Biogenic synthesis and antimicrobial activity of silica-coated silver nanoparticles for esthetic dental applications. J Dent. 2020;96: 103327.

Moreno-Martin G, Pescuma M, Pérez-Corona T, Mozzi F, Madrid Y. Determination of size and mass-and number-based concentration of biogenic SeNPs synthesized by lactic acid bacteria by using a multimethod approach. Anal Chim Acta. 2017;992:34–41.

Naderi M. Surface area: Brunauer–Emmett–Teller (BET). In: Progress in filtration and separation. Elsevier; 2015. p. 585–608.

Balaji S, Mandal BK, Vinod Kumar Reddy L, Sen D. Biogenic ceria nanoparticles (CeO2 NPs) for effective photocatalytic and cytotoxic activity. Bioengineering. 2020;7(1):26.

Article   CAS   PubMed Central   Google Scholar  

Sankar S, Sharma SK, Kim DY. Synthesis and characterization of mesoporous SiO 2 nanoparticles synthesized from biogenic rice husk ash for optoelectronic applications. Int J Eng Sci. 2016;17(1):353–8.

Aher YB, Jain GH, Patil GE, Savale AR, Ghotekar SK, Pore DM, et al. Biosynthesis of copper oxide nanoparticles using leaves extract of Leucaena leucocephala L. and their promising upshot against diverse pathogens. Int J Mol Clin Microbiol. 2017;7(1):776–86.

Ghotekar S, Pansambal S, Pawar SP, Pagar T, Oza R, Bangale S. Biological activities of biogenically synthesized fluorescent silver nanoparticles using Acanthospermum hispidum leaves extract. SN Appl Sci. 2019;1(11):1–12.

Bardestani R, Patience GS, Kaliaguine S. Experimental methods in chemical engineering: specific surface area and pore size distribution measurements—BET, BJH, and DFT. Can J Chem Eng. 2019;97(11):2781–91.

Gelb LD, Gubbins KE. Pore size distributions in porous glasses: a computer simulation study. Langmuir. 1999;15(2):305–8.

Epp J. X-ray diffraction (XRD) techniques for materials characterization. In: Materials characterization using nondestructive evaluation (NDE) methods. Elsevier; 2016. p. 81–124.

Hazarika M, Borah D, Bora P, Silva AR, Das P. Biogenic synthesis of palladium nanoparticles and their applications as catalyst and antimicrobial agent. PLoS ONE. 2017;12(9): e0184936.

Groarke R, Vijayaraghavan RK, Powell D, Rennie A, Brabazon D. Powder characterization—methods, standards, and state of the art. In: Fundamentals of laser powder bed fusion of metals. Elsevier; 2021. p. 491–527.

Nasrollahzadeh M, Atarod M, Sajjadi M, Sajadi SM, Issaabadi Z. Plant-mediated green synthesis of nanostructures: mechanisms, characterization, and applications. In: Interface science and technology. Elsevier; 2019. p. 199–322.

Goldstein JI, Newbury DE, Michael JR, Ritchie NWM, Scott JHJ, Joy DC. Scanning electron microscopy and X-ray microanalysis. Cham: Springer; 2017.

Balasubramanian S, Kala SMJ, Pushparaj TL. Biogenic synthesis of gold nanoparticles using Jasminum auriculatum leaf extract and their catalytic, antimicrobial and anticancer activities. J Drug Deliv Sci Technol. 2020;57: 101620.

Khan M, Khan M, Kuniyil M, Adil SF, Al-Warthan A, Alkhathlan HZ, et al. Biogenic synthesis of palladium nanoparticles using Pulicaria glutinosa extract and their catalytic activity towards the Suzuki coupling reaction. Dalt Trans. 2014;43(24):9026–31.

Barabadi H, Kobarfard F, Vahidi H. Biosynthesis and characterization of biogenic tellurium nanoparticles by using Penicillium chrysogenum PTCC 5031: a novel approach in gold biotechnology. Iran J Pharm Res IJPR. 2018;17(Suppl2):87.

CAS   PubMed   Google Scholar  

Fayaz M, Tiwary CS, Kalaichelvan PT, Venkatesan R. Blue orange light emission from biogenic synthesized silver nanoparticles using Trichoderma viride . Colloids Surf B Biointerfaces. 2010;75(1):175–8.

Otten MT. High-Angle annular dark-field imaging on a tem/stem system. J Electron Microsc Tech. 1991;17(2):221–30.

Utsunomiya S, Ewing RC. Application of high-angle annular dark field scanning transmission electron microscopy, scanning transmission electron microscopy-energy dispersive X-ray spectrometry, and energy-filtered transmission electron microscopy to the characterization of nanopar. Environ Sci Technol. 2003;37(4):786–91.

Haverkamp RG, Marshall AT, van Agterveld D. Pick your carats: nanoparticles of gold–silver–copper alloy produced in vivo. J Nanoparticle Res. 2007;9(4):697–700.

Hossain M, Polash SA, Takikawa M, Shubhra RD, Saha T, Islam Z, et al. Investigation of the antibacterial activity and in vivo cytotoxicity of biogenic silver nanoparticles as potent therapeutics. Front Bioeng Biotechnol. 2019;7:239.

Article   PubMed   PubMed Central   Google Scholar  

Kimber RL, Lewis EA, Parmeggiani F, Smith K, Bagshaw H, Starborg T, et al. Biosynthesis and characterization of copper nanoparticles using Shewanella oneidensis : application for click chemistry. Small. 2018;14(10):1703145.

Fadley CS. X-ray photoelectron spectroscopy: progress and perspectives. J Electron Spectros Relat Phenomena. 2010;178:2–32.

Lykhach Y, Kozlov SM, Skála T, Tovt A, Stetsovych V, Tsud N, et al. Counting electrons on supported nanoparticles. Nat Mater. 2016;15(3):284–8.

Sneha K, Sathishkumar M, Lee SY, Bae MA, Yun Y-S. Biosynthesis of Au nanoparticles using cumin seed powder extract. J Nanosci Nanotechnol. 2011;11(2):1811–4.

Aygun A, Gülbagca F, Ozer LY, Ustaoglu B, Altunoglu YC, Baloglu MC, et al. Biogenic platinum nanoparticles using black cumin seed and their potential usage as antimicrobial and anticancer agent. J Pharm Biomed Anal. 2020;179: 112961.

Gulbagca F, Ozdemir S, Gulcan M, Sen F. Synthesis and characterization of Rosa canina-mediated biogenic silver nanoparticles for anti-oxidant, antibacterial, antifungal, and DNA cleavage activities. Heliyon. 2019;5(12): e02980.

Huo Y-C, Li W-W, Chen C-B, Li C-X, Zeng R, Lau T-C, et al. Biogenic FeS accelerates reductive dechlorination of carbon tetrachloride by Shewanella putrefaciens CN32. Enzyme Microb Technol. 2016;95:236–41.

Manor J, Feldblum ES, Zanni MT, Arkin IT. Environment polarity in proteins mapped noninvasively by FTIR spectroscopy. J Phys Chem Lett. 2012;3(7):939–44.

Deepty M, Srinivas C, Kumar ER, Mohan NK, Prajapat CL, Rao TVC, et al. XRD, EDX, FTIR and ESR spectroscopic studies of co-precipitated Mn-substituted Zn–ferrite nanoparticles. Ceram Int. 2019;45(6):8037–44.

Chevali V, Kandare E. Rigid biofoam composites as eco-efficient construction materials. In: Biopolymers and biotech admixtures for eco-efficient construction materials. Elsevier; 2016. p. 275–304.

Składanowski M, Golinska P, Rudnicka K, Dahm H, Rai M. Evaluation of cytotoxicity, immune compatibility and antibacterial activity of biogenic silver nanoparticles. Med Microbiol Immunol. 2016;205(6):603–13.

Tugarova AV, Mamchenkova PV, Dyatlova YA, Kamnev AA. FTIR and Raman spectroscopic studies of selenium nanoparticles synthesised by the bacterium Azospirillum thiophilum . Spectrochim Acta Part A Mol Biomol Spectrosc. 2018;192:458–63.

Sikora A, Bartczak D, Geißler D, Kestens V, Roebben G, Ramaye Y, et al. A systematic comparison of different techniques to determine the zeta potential of silica nanoparticles in biological medium. Anal methods. 2015;7(23):9835–43.

Gavade NL, Kadam AN, Suwarnkar MB, Ghodake VP, Garadkar KM. Biogenic synthesis of multi-applicative silver nanoparticles by using Ziziphus jujuba leaf extract. Spectrochim Acta Part A Mol Biomol Spectrosc. 2015;136:953–60.

Edison TJI, Sethuraman MG. Biogenic robust synthesis of silver nanoparticles using Punica granatum peel and its application as a green catalyst for the reduction of an anthropogenic pollutant 4-nitrophenol. Spectrochim Acta Part A Mol Biomol Spectrosc. 2013;104:262–4.

Ballottin D, Fulaz S, Souza ML, Corio P, Rodrigues AG, Souza AO, et al. Elucidating protein involvement in the stabilization of the biogenic silver nanoparticles. Nanoscale Res Lett. 2016;11(1):1–9.

Fayaz AM, Balaji K, Girilal M, Yadav R, Kalaichelvan PT, Venketesan R. Biogenic synthesis of silver nanoparticles and their synergistic effect with antibiotics: a study against gram-positive and gram-negative bacteria. Nanomed Nanotechnol Biol Med. 2010;6(1):103–9.

Menon S, KS SD, Agarwal H, Shanmugam VK. Efficacy of biogenic selenium nanoparticles from an extract of ginger towards evaluation on anti-microbial and anti-oxidant activities. Colloid Interface Sci Commun. 2019;29:1–8. https://doi.org/10.1016/j.colcom.2018.12.004

Chooto P. Cyclic voltammetry and its applications. In: Voltammetry. IntechOpen; 2019. p. 1.

Saw EN, Grasmik V, Rurainsky C, Epple M, Tschulik K. Electrochemistry at single bimetallic nanoparticles—using nano impacts for sizing and compositional analysis of individual AgAu alloy nanoparticles. Faraday Discuss. 2016;193:327–38.

Testolin A, Cattaneo S, Wang W, Wang D, Pifferi V, Prati L, et al. Cyclic voltammetry characterization of Au, Pd, and AuPd nanoparticles supported on different carbon nanofibers. Surfaces. 2019;2(1):205–15.

Khan AU, Wei Y, Khan ZUH, Tahir K, Khan SU, Ahmad A, et al. Electrochemical and antioxidant properties of biogenic silver nanoparticles. Int J Electrochem Sci. 2015;10(10):7905–16.

Roy N, Mondal S, Laskar RA, Basu S, Mandal D, Begum NA. Biogenic synthesis of Au and Ag nanoparticles by Indian propolis and its constituents. Colloids Surf B Biointerfaces. 2010;76(1):317–25.

Long DA. Raman spectroscopy. New York. 1977;1.

Huang M, Yan H, Chen C, Song D, Heinz TF, Hone J. Phonon softening and crystallographic orientation of strained graphene studied by Raman spectroscopy. Proc Natl Acad Sci. 2009;106(18):7304–8.

Lin T, Song Y-L, Liao J, Liu F, Zeng T-T. Applications of surface-enhanced Raman spectroscopy in detection fields. Nanomedicine. 2020;15(30):2971–89.

Prasad C, Yuvaraja G, Venkateswarlu P. Biogenic synthesis of Fe 3 O 4 magnetic nanoparticles using Pisum sativum peels extract and its effect on magnetic and methyl orange dye degradation studies. J Magn Magn Mater. 2017;424:376–81.

Anghel L, Balasoiu M, Ishchenko LA, Stolyar S V, Kurkin TS, Rogachev A V, et al. Characterization of bio-synthesized nanoparticles produced by Klebsiella oxytoca. In: Journal of Physics: Conference Series. IOP Publishing; 2012. p. 12005.

Lahr RH, Vikesland PJ. Surface-enhanced Raman spectroscopy (SERS) cellular imaging of intracellulary biosynthesized gold nanoparticles. ACS Sustain Chem Eng. 2014;2(7):1599–608.

Skoog DA, Holler FJ, Crouch SR, editors. Principles of instrumental analysis (7th edn). Boston, USA: Cengage learning; 2017. ISBN 978-1-305-57721-3

Patel S, Patel P, Undre SB, Pandya SR, Singh M, Bakshi S. DNA binding and dispersion activities of titanium dioxide nanoparticles with UV/vis spectrophotometry, fluorescence spectroscopy and physicochemical analysis at physiological temperature. J Mol Liq. 2016;213:304–11.

Al-Hakkani MF. Biogenic copper nanoparticles and their applications: a review. SN Appl Sci. 2020;2(3):1–20.

Harne S, Sharma A, Dhaygude M, Joglekar S, Kodam K, Hudlikar M. Novel route for rapid biosynthesis of copper nanoparticles using aqueous extract of Calotropis procera L. latex and their cytotoxicity on tumor cells. Colloids Surf B Biointerfaces. 2012;95:284–8.

Ismail M, Gul S, Khan MI, Khan MA, Asiri AM, Khan SB. Green synthesis of zerovalent copper nanoparticles for efficient reduction of toxic azo dyes congo red and methyl orange. Green Process Synth. 2019;8(1):135–43.

Hassanien R, Husein DZ, Al-Hakkani MF. Biosynthesis of copper nanoparticles using aqueous Tilia extract: antimicrobial and anticancer activities. Heliyon. 2018;4(12): e01077.

Suresh Y, Annapurna S, Bhikshamaiah G, Singh AK. Green luminescent copper nanoparticles. In: IOP Conference Series: Materials Science and Engineering. IOP Publishing; 2016. p. 12187.

Zhang P, Hong RY, Chen Q, Feng WG. On the electrical conductivity and photocatalytic activity of aluminum-doped zinc oxide. Powder Technol. 2014;253:360–7.

Karthik K, Vijayalakshmi S, Phuruangrat A, Revathi V, Verma U. Multifunctional applications of microwave-assisted biogenic TiO 2 nanoparticles. J Clust Sci. 2019;30(4):965–72.

Jayabalan J, Mani G, Krishnan N, Pernabas J, Devadoss JM, Jang HT. Green biogenic synthesis of zinc oxide nanoparticles using Pseudomonas putida culture and its In vitro antibacterial and anti-biofilm activity. Biocatal Agric Biotechnol. 2019;21: 101327.

Gawade VV, Gavade NL, Shinde HM, Babar SB, Kadam AN, Garadkar KM. Green synthesis of ZnO nanoparticles by using Calotropis procera leaves for the photodegradation of methyl orange. J Mater Sci Mater Electron. 2017;28(18):14033–9.

Tompkins H, Irene EA. Handbook of ellipsometry. William Andrew; 2005.

Losurdo M, Bergmair M, Bruno G, Cattelan D, Cobet C, de Martino A, et al. Spectroscopic ellipsometry and polarimetry for materials and systems analysis at the nanometer scale: state-of-the-art, potential, and perspectives. J Nanoparticle Res. 2009;11(7):1521–54.

Moirangthem RS, Yaseen MT, Wei P-K, Cheng J-Y, Chang Y-C. Enhanced localized plasmonic detections using partially-embedded gold nanoparticles and ellipsometric measurements. Biomed Opt Express. 2012;3(5):899–910.

Lakhwani G, Roijmans RFH, Kronemeijer AJ, Gilot J, Janssen RAJ, Meskers SCJ. Probing charge carrier density in a layer of photodoped ZnO nanoparticles by spectroscopic ellipsometry. J Phys Chem C. 2010;114(35):14804–10.

Claxton J, Joudeh N, Røyne A, Linke D, Mikheenko P. Sequential magnetic mapping of bacteria loaded with Pd-Fe nanoparticles. In: 2020 IEEE 10th International conference nanomaterials: applications & properties (NAP). IEEE; 2020. p. 1–5.

Passeri D, Dong C, Reggente M, Angeloni L, Barteri M, Scaramuzzo FA, et al. Magnetic force microscopy: quantitative issues in biomaterials. Biomatter. 2014;4(1): e29507.

Campaña AL, Joudeh N, Høyer H, Røyne A, Linke D, Mikheenko P. Probing van der Waals and magnetic forces in bacteria with magnetic nanoparticles. In: 2020 IEEE 10th International conference nanomaterials: applications & properties (NAP). IEEE; 2020. p. 01NSSA03-1.

Körnig A, Hartmann MA, Teichert C, Fratzl P, Faivre D. Magnetic force imaging of a chain of biogenic magnetite and Monte Carlo analysis of tip–particle interaction. J Phys D Appl Phys. 2014;47(23): 235403.

Albrecht M, Janke V, Sievers S, Siegner U, Schüler D, Heyen U. Scanning force microspy study of biogenic nanoparticles for medical applications. J Magn Magn Mater. 2005;290:269–71.

Campaña AL, Joudeh N, Mikheenko P, Linke D. Magnetic decoration of Escherichia coli loaded with Palladium nanoparticles. In: 2021 IEEE 11th International conference nanomaterials: applications and properties (NAP). IEEE; 2021. p. 1–5.

Foner S. Vibrating sample magnetometer. Rev Sci Instrum. 1956;27(7):548.

Kirupakar BR, Vishwanath BA, Sree MP. Vibrating sample magnetometer and its application in characterisation of magnetic property of the anti cancer drug magnetic microspheres. Int J Pharm Drug Anal. 2016;4(5):227–33.

Yadav VK, Fulekar MH. Biogenic synthesis of maghemite nanoparticles (γ-Fe 2 O 3 ) using Tridax leaf extract and its application for removal of fly ash heavy metals (Pb, Cd). Mater Today Proc. 2018;5(9):20704–10.

Tovar GI, Briceño S, Suarez J, Flores S, González G. Biogenic synthesis of iron oxide nanoparticles using Moringa oleifera and chitosan and its evaluation on corn germination. Environ Nanotechnol Monit Manag. 2020;14: 100350.

Sawicki M, Stefanowicz W, Ney A. Sensitive SQUID magnetometry for studying nanomagnetism. Semicond Sci Technol. 2011;26(6):64006.

Colclough MS, Gough CE, Keene M, Muirhead CM, Thomas N, Abell JS, et al. Radio-frequency SQUID operation using a ceramic high-temperature superconductor. Nature. 1987;328(6125):47–8.

Enpuku K, Minotani T, Gima T, Kuroki Y, Itoh Y, Yamashita M, et al. Detection of magnetic nanoparticles with superconducting quantum interference device (SQUID) magnetometer and application to immunoassays. Jpn J Appl Phys. 1999;38(10A):L1102.

Lingamdinne LP, Chang Y-Y, Yang J-K, Singh J, Choi E-H, Shiratani M, et al. Biogenic reductive preparation of magnetic inverse spinel iron oxide nanoparticles for the adsorption removal of heavy metals. Chem Eng J. 2017;307:74–84.

Byrne JM, Coker VS, Cespedes E, Wincott PL, Vaughan DJ, Pattrick RAD, et al. Biosynthesis of zinc substituted magnetite nanoparticles with enhanced magnetic properties. Adv Funct Mater. 2014;24(17):2518–29.

Atherton NM, Davies MJ, Gilbert BC. Electron spin resonance. Vol. 14. Royal Society of Chemistry; 1994.

Flores-Arias Y, Vázquez-Victorio G, Ortega-Zempoalteca R, Acevedo-Salas U, Ammar S, Valenzuela R. Magnetic phase transitions in ferrite nanoparticles characterized by electron spin resonance. J Appl Phys. 2015;117(17):17A503.

Rubinstein M, Kodama RH, Makhlouf SA. Electron spin resonance study of NiO antiferromagnetic nanoparticles. J Magn Magn Mater. 2001;234(2):289–93.

Nasibova A, Khalilov R, Abiyev H, Trubitsin B, Eftekhari A. Identification of the EPR signals of fig leaves (Ficus carica L.). Eurasian Chem Commun. 2021;3(3):193–9.

Dixit R, Gupta A, Jordan N, Zhou S, Schild D, Weiss S, et al. Magnetic properties of biogenic selenium nanomaterials. Environ Sci Pollut Res. 2021. https://doi.org/10.1007/s11356-020-11683-2 .

Charsley EL, Laye PG, Palakollu V, Rooney JJ, Joseph B. DSC studies on organic melting point temperature standards. Thermochim Acta. 2006;446(1–2):29–32.

Horiuchi K. DSC studies on structural phase transitions and molecular motions in some A2MCl4 compounds. Phys Status Solidi. 2004;201(4):723–6.

Wang J, Xie H, Guo Z, Guan L, Li Y. Improved thermal properties of paraffin wax by the addition of TiO 2 nanoparticles. Appl Therm Eng. 2014;73(2):1541–7.

Illers K-H, Kanig G. Heat of fusion and lamellar structure of polyethylene single crystal mats. Colloid Polym Sci. 1982;260(6):564–9.

Pérez-Alonso C, Cruz-Olivares J, Barrera-Pichardo JF, Rodríguez-Huezo ME, Báez-González JG, Vernon-Carter EJ. DSC thermo-oxidative stability of red chili oleoresin microencapsulated in blended biopolymers matrices. J Food Eng. 2008;85(4):613–24.

Ontong JC, Singh S, Nwabor OF, Chusri S, Voravuthikunchai SP. Potential of antimicrobial topical gel with synthesized biogenic silver nanoparticle using Rhodomyrtus tomentosa leaf extract and silk sericin. Biotechnol Lett. 2020;42(12):2653–64.

Ahsan A, Farooq MA, Ahsan Bajwa A, Parveen A. Green synthesis of silver nanoparticles using Parthenium hysterophorus : optimization, characterization and in vitro therapeutic evaluation. Molecules. 2020;25(15):3324.

Tanzi MC, Farè S, Candiani G. Foundations of biomaterials engineering. Cambridge: Academic Press; 2019.

Thomas S, Thomas R, Zachariah AK, Kumar R. Thermal and rheological measurement techniques for nanomaterials characterization, vol. 3. Amsterdam: Elsevier; 2017.

Song P, Wen D, Guo ZX, Korakianitis T. Oxidation investigation of nickel nanoparticles. Phys Chem Chem Phys. 2008;10(33):5057–65.

Wagner M. Thermal analysis in practice. Munich, Germany: Hanser Publications; 2009. ISBN 978-1-56990-643-9

Ajroudi L, Mliki N, Bessais L, Madigou V, Villain S, Leroux C. Magnetic, electric and thermal properties of cobalt ferrite nanoparticles. Mater Res Bull. 2014;59:49–58.

Loganathan S, Valapa RB, Mishra RK, Pugazhenthi G, Thomas S. Thermogravimetric analysis for characterization of nanomaterials. In: Thermal and rheological measurement techniques for nanomaterials characterization. Elsevier; 2017. p. 67–108.

Rami JM, Patel CD, Patel CM, Patel MV. Thermogravimetric analysis (TGA) of some synthesized metal oxide nanoparticles. Mater Today Proc. 2021;43:655–9.

Pang LSK, Saxby JD, Chatfield SP. Thermogravimetric analysis of carbon nanotubes and nanoparticles. J Phys Chem. 1993;97(27):6941–2.

Saadatkhah N, Carillo Garcia A, Ackermann S, Leclerc P, Latifi M, Samih S, et al. Experimental methods in chemical engineering: thermogravimetric analysis—TGA. Can J Chem Eng. 2020;98(1):34–43.

Shah A, Lutfullah G, Ahmad K, Khalil AT, Maaza M. Daphne mucronata-mediated phytosynthesis of silver nanoparticles and their novel biological applications, compatibility and toxicity studies. Green Chem Lett Rev. 2018;11(3):318–33.

Nguyen TM-T, Huynh TT-T, Dang C-H, Mai D-T, Nguyen TT-N, Nguyen D-T, et al. Novel biogenic silver nanoparticles used for antibacterial effect and catalytic degradation of contaminants. Res Chem Intermed. 2020;46(3):1975–90.

Healy JJ, De Groot JJ, Kestin J. The theory of the transient hot-wire method for measuring thermal conductivity. Physica B + c. 1976;82(2):392–408.

Kumari MM, Philip D. Synthesis of biogenic SnO2 nanoparticles and evaluation of thermal, rheological, antibacterial and antioxidant activities. Powder Technol. 2015;270:312–9.

Rufus A, Sreeju N, Philip D. Synthesis of biogenic hematite (α-Fe 2 O 3) nanoparticles for antibacterial and nanofluid applications. RSC Adv. 2016;6(96):94206–17.

Davis JR. Tensile testing. ASM international; 2004.

Hernández-Gómora AE, Lara-Carrillo E, Robles-Navarro JB, Scougall-Vilchis RJ, Hernández-López S, Medina-Solís CE, et al. Biosynthesis of silver nanoparticles on orthodontic elastomeric modules: evaluation of mechanical and antibacterial properties. Molecules. 2017;22(9):1407.

Batool S, Hussain Z, Niazi MBK, Liaqat U, Afzal M. Biogenic synthesis of silver nanoparticles and evaluation of physical and antimicrobial properties of Ag/PVA/starch nanocomposites hydrogel membranes for wound dressing application. J Drug Deliv Sci Technol. 2019;52:403–14.

Schuh CA. Nanoindentation studies of materials. Mater Today. 2006;9(5):32–40.

Polishchuk I, Bracha AA, Bloch L, Levy D, Kozachkevich S, Etinger-Geller Y, et al. Coherently aligned nanoparticles within a biogenic single crystal: a biological prestressing strategy. Science (80-). 2017;358(6368):1294–8.

Xuexia Z. Mechanical properties of silica cells in bamboo measured using in situ imaging nanoindentation. Wood Fiber Sci. 2016;48(4):1–6.

Franck A, Germany TI. Viscoelasticity and dynamic mechanical testing. TA Instruments, New Castle, DE, USA AN004. 1993;

Siripanth J, Wongwitthayakool P. Flexural strength and viscoelastic properties of acrylic resin denture base material containing silver nanoparticle synthesized from fingerroot aqueous extract. In: Key engineering materials. Trans Tech Publ; 2018. p. 178–82.

Bettaieb F, Khiari R, Dufresne A, Mhenni MF, Belgacem MN. Mechanical and thermal properties of Posidonia oceanica cellulose nanocrystal reinforced polymer. Carbohydr Polym. 2015;123:99–104.

Huang X, Jain PK, El-Sayed IH, El-Sayed MA. Gold nanoparticles: interesting optical properties and recent applications in cancer diagnostics and therapy. Nanomedicine. 2007. https://doi.org/10.2217/17435889.2.5.681 .

El-Sayed IH, Huang X, El-Sayed MA. Selective laser photo-thermal therapy of epithelial carcinoma using anti-EGFR antibody conjugated gold nanoparticles. Cancer Lett. 2006;239(1):129–35.

Elahi N, Kamali M, Baghersad MH. Recent biomedical applications of gold nanoparticles: a review. Talanta. 2018;184:537–56.

Chen C, Xing G, Wang J, Zhao Y, Li B, Tang J, et al. Multihydroxylated [Gd@ C82 (OH) 22] n nanoparticles: antineoplastic activity of high efficiency and low toxicity. Nano Lett. 2005;5(10):2050–7.

Meng H, Xing G, Blanco E, Song Y, Zhao L, Sun B, et al. Gadolinium metallofullerenol nanoparticles inhibit cancer metastasis through matrix metalloproteinase inhibition: imprisoning instead of poisoning cancer cells. Nanomed Nanotechnol Biol Med. 2012;8(2):136–46.

Swanson SD, Kukowska-Latallo JF, Patri AK, Chen C, Ge S, Cao Z, et al. Targeted gadolinium-loaded dendrimer nanoparticles for tumor-specific magnetic resonance contrast enhancement. Int J Nanomed. 2008;3(2):201.

Rasmussen JW, Martinez E, Louka P, Wingett DG. Zinc oxide nanoparticles for selective destruction of tumor cells and potential for drug delivery applications. Expert Opin Drug Deliv. 2010;7(9):1063–77.

Chen F-H, Gao Q, Ni JZ. The grafting and release behavior of doxorubincin from Fe 3 O 4 @ SiO 2 core–shell structure nanoparticles via an acid cleaving amide bond: the potential for magnetic targeting drug delivery. Nanotechnology. 2008;19(16): 165103.

Chertok B, Moffat BA, David AE, Yu F, Bergemann C, Ross BD, et al. Iron oxide nanoparticles as a drug delivery vehicle for MRI monitored magnetic targeting of brain tumors. Biomaterials. 2008;29(4):487–96.

Hutter E, Maysinger D. Gold nanoparticles and quantum dots for bioimaging. Microsc Res Tech. 2011;74(7):592–604.

Saha K, Agasti SS, Kim C, Li X, Rotello VM. Gold nanoparticles in chemical and biological sensing. Chem Rev. 2012;112(5):2739–79.

Zeng S, Yong K-T, Roy I, Dinh X-Q, Yu X, Luan F. A review on functionalized gold nanoparticles for biosensing applications. Plasmonics. 2011;6(3):491–506.

Bhumkar DR, Joshi HM, Sastry M, Pokharkar VB. Chitosan reduced gold nanoparticles as novel carriers for transmucosal delivery of insulin. Pharm Res. 2007;24(8):1415–26.

Phillips RL, Miranda OR, You C, Rotello VM, Bunz UHF. Rapid and efficient identification of bacteria using gold-nanoparticle–poly (para-phenyleneethynylene) constructs. Angew Chemie Int Ed. 2008;47(14):2590–4.

Kairdolf BA, Qian X, Nie S. Bioconjugated nanoparticles for biosensing, in vivo imaging, and medical diagnostics. Anal Chem. 2017;89(2):1015–31.

Ahmadi A, Mirzaeizadeh Z, Omidfar K. Simultaneous detection of SARS-CoV-2 IgG/IgM antibodies, using gold nanoparticles-based lateral flow immunoassay. Monoclon Antib Immunodiagn Immunother. 2021;40(5):210–8.

Hajipour MJ, Fromm KM, Ashkarran AA, de Aberasturi DJ, de Larramendi IR, Rojo T, et al. Antibacterial properties of nanoparticles. Trends Biotechnol. 2012;30(10):499–511.

Pant HR, Pant B, Sharma RK, Amarjargal A, Kim HJ, Park CH, et al. Antibacterial and photocatalytic properties of Ag/TiO 2 /ZnO nano-flowers prepared by facile one-pot hydrothermal process. Ceram Int. 2013;39(2):1503–10.

Bouzigues C, Gacoin T, Alexandrou A. Biological applications of rare-earth based nanoparticles. ACS Nano. 2011;5(11):8488–505.

Hifumi H, Yamaoka S, Tanimoto A, Akatsu T, Shindo Y, Honda A, et al. Dextran coated gadolinium phosphate nanoparticles for magnetic resonance tumor imaging. J Mater Chem. 2009;19(35):6393–9.

Türkcan S, Masson J-B, Casanova D, Mialon G, Gacoin T, Boilot J-P, et al. Observing the confinement potential of bacterial pore-forming toxin receptors inside rafts with nonblinking Eu3+-doped oxide nanoparticles. Biophys J. 2012;102(10):2299–308.

Gu L, Zhang M, He J, Ni P. A porous cross-linked gel polymer electrolyte separator for lithium-ion batteries prepared by using zinc oxide nanoparticle as a foaming agent and filler. Electrochim Acta. 2018;292:769–78.

Lu Y-C, Xu Z, Gasteiger HA, Chen S, Hamad-Schifferli K, Shao-Horn Y. Platinum−gold nanoparticles: a highly active bifunctional electrocatalyst for rechargeable lithium−air batteries. J Am Chem Soc. 2010;132(35):12170–1.

Rodríguez-Mas F, Ferrer JC, Alonso JL, Fernández de Ávila S. Expanded electroluminescence in high load CdS nanocrystals PVK-based LEDs. Nanomaterials. 2019;9(9):1212.

Qi H, Hegmann T. Impact of nanoscale particles and carbon nanotubes on current and future generations of liquid crystal displays. J Mater Chem. 2008;18(28):3288–94.

Usman M, Farooq M, Wakeel A, Nawaz A, Cheema SA, Rehman H, et al. Nanotechnology in agriculture: current status, challenges and future opportunities. Sci Total Environ. 2020;721: 137778.

Rameshaiah GN, Pallavi J, Shabnam S. Nano fertilizers and nano sensors—an attempt for developing smart agriculture. Int J Eng Res Gen Sci. 2015;3(1):314–20.

Mastronardi E, Tsae P, Zhang X, Monreal C, DeRosa MC. Strategic role of nanotechnology in fertilizers: potential and limitations. In: Nanotechnologies in food and agriculture. Springer; 2015. p. 25–67.

Changmei L, Chaoying Z, Junqiang W, Guorong W, Mingxuan T. Research of the effect of nanometer materials on germination and growth enhancement of glycine max and its mechanism. Soybean Sci. 2002;21(3):168–71.

Dimkpa CO, Bindraban PS, Fugice J, Agyin-Birikorang S, Singh U, Hellums D. Composite micronutrient nanoparticles and salts decrease drought stress in soybean. Agron Sustain Dev. 2017;37(1):5.

Delfani M, Baradarn Firouzabadi M, Farrokhi N, Makarian H. Some physiological responses of black-eyed pea to iron and magnesium nanofertilizers. Commun Soil Sci Plant Anal. 2014;45(4):530–40.

Dikshit PK, Kumar J, Das AK, Sadhu S, Sharma S, Singh S, et al. Green synthesis of metallic nanoparticles: applications and limitations. Catalysts. 2021;11(8):902.

Paret ML, Vallad GE, Averett DR, Jones JB, Olson SM. Photocatalysis: effect of light-activated nanoscale formulations of TiO2 on Xanthomonas perforans and control of bacterial spot of tomato. Phytopathology. 2013;103(3):228–36.

Ayoub HA, Khairy M, Elsaid S, Rashwan FA, Abdel-Hafez HF. Pesticidal activity of nanostructured metal oxides for generation of alternative pesticide formulations. J Agric Food Chem. 2018;66(22):5491–8.

Cromwell WA, Yang J, Starr JL, Jo Y-K. Nematicidal effects of silver nanoparticles on root-knot nematode in bermudagrass. J Nematol. 2014;46(3):261.

CAS   PubMed   PubMed Central   Google Scholar  

Othman SH, Abd Salam NR, Zainal N, Kadir Basha R, Talib RA. Antimicrobial activity of TiO2 nanoparticle-coated film for potential food packaging applications. Int J Photoenergy. 2014;2014:945930. https://doi.org/10.1155/2014/945930

Cui S, Yang L, Wang J, Wang X. Fabrication of a sensitive gas sensor based on PPy/TiO 2 nanocomposites films by layer-by-layer self-assembly and its application in food storage. Sensors Actuators B Chem. 2016;233:337–46.

Carbone M, Donia DT, Sabbatella G, Antiochia R. Silver nanoparticles in polymeric matrices for fresh food packaging. J King Saud Univ. 2016;28(4):273–9.

Mahdi SS, Vadood R, Nourdahr R. Study on the antimicrobial effect of nanosilver tray packaging of minced beef at refrigerator temperature. Glob Vet. 2012;9:284–9.

Roy R, Kumar S, Tripathi A, Das M, Dwivedi PD. Interactive threats of nanoparticles to the biological system. Immunol Lett. 2014;158(1–2):79–87.

Schwartz J, Litonjua A, Suh H, Verrier M, Zanobetti A, Syring M, et al. Traffic related pollution and heart rate variability in a panel of elderly subjects. Thorax. 2005;60(6):455–61.

Adar SD, Gold DR, Coull BA, Schwartz J, Stone PH, Suh H. Focused exposures to airborne traffic particles and heart rate variability in the elderly. Epidemiology. 2007. https://doi.org/10.1097/01.ede.0000249409.81050.46 .

Long TC, Saleh N, Tilton RD, Lowry GV, Veronesi B. Titanium dioxide (P25) produces reactive oxygen species in immortalized brain microglia (BV2): implications for nanoparticle neurotoxicity. Environ Sci Technol. 2006;40(14):4346–52.

Stark WJ. Nanoparticles in biological systems. Angew Chemie Int Ed. 2011;50(6):1242–58.

Lin D, Xing B. Phytotoxicity of nanoparticles: inhibition of seed germination and root growth. Environ Pollut. 2007;150(2):243–50.

Yang L, Watts DJ. Particle surface characteristics may play an important role in phytotoxicity of alumina nanoparticles. Toxicol Lett. 2005;158(2):122–32.

Srivastava SK, Constanti M. Room temperature biogenic synthesis of multiple nanoparticles (Ag, Pd, Fe, Rh, Ni, Ru, Pt Co, and Li) by Pseudomonas aeruginosa SM1. J Nanoparticle Res. 2012;14(4):1–10.

Arya A, Gupta K, Chundawat TS, Vaya D. Biogenic synthesis of copper and silver nanoparticles using green alga Botryococcus braunii and its antimicrobial activity. Bioinorg Chem Appl. 2018. https://doi.org/10.1155/2018/7879403 .

Mishra A, Ahmad R, Perwez M, Sardar M. Reusable green synthesized biomimetic magnetic nanoparticles for glucose and H 2 O 2 detection. Bionanoscience. 2016;6(2):93–102.

Download references

Acknowledgements

This work was supported by the Research Council of Norway, Grant 294605 (Center for Digital Life) to DL.

Author information

Authors and affiliations.

Department of Biosciences, University of Oslo, Blindern, P.O. Box 1066, 0316, Oslo, Norway

Nadeem Joudeh & Dirk Linke

You can also search for this author in PubMed   Google Scholar

Contributions

NJ wrote the manuscript. DL edited the manuscript. Both the authors read and approved the final manuscript.

Corresponding author

Correspondence to Dirk Linke .

Ethics declarations

Ethics approval and consent to participate, consent for publication, competing interests.

The authors declare that they have no competing interests.

Additional information

Publisher's note.

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ . The Creative Commons Public Domain Dedication waiver ( http://creativecommons.org/publicdomain/zero/1.0/ ) applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and permissions

About this article

Cite this article.

Joudeh, N., Linke, D. Nanoparticle classification, physicochemical properties, characterization, and applications: a comprehensive review for biologists. J Nanobiotechnol 20 , 262 (2022). https://doi.org/10.1186/s12951-022-01477-8

Download citation

Received : 02 February 2022

Accepted : 23 May 2022

Published : 07 June 2022

DOI : https://doi.org/10.1186/s12951-022-01477-8

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

  • Nanomaterials
  • Metal nanoparticles
  • Biogenic nanoparticles
  • Bionanoparticles
  • Nanobiotechnology
  • Characterization of nanomaterials

Journal of Nanobiotechnology

ISSN: 1477-3155

nanoparticle review nature

Information

  • Author Services

Initiatives

You are accessing a machine-readable page. In order to be human-readable, please install an RSS reader.

All articles published by MDPI are made immediately available worldwide under an open access license. No special permission is required to reuse all or part of the article published by MDPI, including figures and tables. For articles published under an open access Creative Common CC BY license, any part of the article may be reused without permission provided that the original article is clearly cited. For more information, please refer to https://www.mdpi.com/openaccess .

Feature papers represent the most advanced research with significant potential for high impact in the field. A Feature Paper should be a substantial original Article that involves several techniques or approaches, provides an outlook for future research directions and describes possible research applications.

Feature papers are submitted upon individual invitation or recommendation by the scientific editors and must receive positive feedback from the reviewers.

Editor’s Choice articles are based on recommendations by the scientific editors of MDPI journals from around the world. Editors select a small number of articles recently published in the journal that they believe will be particularly interesting to readers, or important in the respective research area. The aim is to provide a snapshot of some of the most exciting work published in the various research areas of the journal.

Original Submission Date Received: .

  • Active Journals
  • Find a Journal
  • Proceedings Series
  • For Authors
  • For Reviewers
  • For Editors
  • For Librarians
  • For Publishers
  • For Societies
  • For Conference Organizers
  • Open Access Policy
  • Institutional Open Access Program
  • Special Issues Guidelines
  • Editorial Process
  • Research and Publication Ethics
  • Article Processing Charges
  • Testimonials
  • Preprints.org
  • SciProfiles
  • Encyclopedia

nanomaterials-logo

Article Menu

nanoparticle review nature

  • Subscribe SciFeed
  • Recommended Articles
  • Google Scholar
  • on Google Scholar
  • Table of Contents

Find support for a specific problem in the support section of our website.

Please let us know what you think of our products and services.

Visit our dedicated information section to learn more about MDPI.

JSmol Viewer

Recent advances in research from nanoparticle to nano-assembly: a review.

nanoparticle review nature

1. Introduction

2. oriented assembly of nanomaterials, 3. stimuli dependent techniques, 3.1. chemical stimuli-based self-assembly of nanomaterials, 3.1.1. solvent-induced self-assembly.

Click here to enlarge figure

3.1.2. Acid–Base-Induced Self-Assembly

3.1.3. bio-macromolecule-induced self-assembly, 3.1.4. metal ion-induced self-assembly, 3.1.5. gas-induced self-assembly, 3.2. physical stimuli-based self-assembly of nanomaterials, 3.2.1. light-induced self-assembly, 3.2.2. magnetic-induced self-assembly, 3.2.3. electric field-induced self-assembly, 3.2.4. temperature-induced self-assembly, 4. futuristic scope and perspectives, 5. conclusions, conflicts of interest, abbreviations.

APTES3-Aminopropyltriethoxysilane
AIArtificial Intelligence
BNSLBinary Nanocrystals Super Lattices
BSPPBis(p-Sulfonatophenyl)-Phenyl Phosphine
CTABCetyl Trimethyl Ammonium Bromide
CSNECryosoret Nano-Engineering
DMSODimethyl Sulfoxide
DCMDichloromethane
DDADodecylamine
DNADeoxyribonucleic Acid
EDTAEthylenediaminetetraacetic Acid
FRETFluorescence Resonance Energy Transfer
HAADF-STEMHigh-Angle Annular Dark-Field Scanning Transmission Electron Microscopy
HSNsHollow Spherical Nanostructures
HPAHexylphosphonic Acid
HRTEMHigh Resolution Transmission Electron Microscopy
IoTInternet-of-Things
LSPRLocalized Surface Plasmon Resonance
MEMSMicroelectromechanical
NPOMNanoparticle-on-Mirror
NPs Nanoparticles
NMsNanomaterials
NCsNanocrystals
NANano-Assembly
NRsNanorods
OAOriented-Assembly
OlamOleyamine
ODPAOctadecyl Phosphonic Acid
PSPolystyrene
P4VPPoly(4-Vinyl Pyridine)
PBuAPolybutyl Acrylate
RhBRhodamine B
SASelf-Assembly
SPCESurface Plasmon-Coupled Emission
SPPsSurface plasmon polaritons
SAEDSelected Area Electron Diffraction
SAMSelf-assembly monolayer
SERSSurface-Enhanced Raman Scattering
TPsTetrapods
TEMTransmission Electron Microscopy
THFTetrahydrofuran
T-DDTt-dodecanethiol
1DOne Dimensional
2DTwo Dimensional
3DThree Dimensional
  • Albrecht, M.A.; Evans, C.W.; Raston, C.L. Green Chemistry and the Health Implications of Nanoparticles. Green Chem. 2006 , 8 , 417–432. [ Google Scholar ] [ CrossRef ]
  • Badshah, M.A.; Koh, N.Y.; Zia, A.W.; Abbas, N.; Zahra, Z.; Saleem, M.W. Recent Developments in Plasmonic Nanostructures for Metal Enhanced Fluorescence-Based Biosensing. Nanomaterials 2020 , 10 , 1749. [ Google Scholar ] [ CrossRef ]
  • Che, C.; Xue, R.; Li, N.; Gupta, P.; Wang, X.; Zhao, B.; Singamaneni, S.; Nie, S.; Cunningham, B.T. Accelerated Digital Biodetection Using Magneto-Plasmonic Nanoparticle-Coupled Photonic Resonator Absorption Microscopy. ACS Nano 2022 , 16 , 2345–2354. [ Google Scholar ] [ CrossRef ]
  • Chauhan, N.; Xiong, Y.; Ren, S.; Dwivedy, A.; Magazine, N.; Zhou, L.; Jin, X.; Zhang, T.; Cunningham, B.T.; Yao, S.; et al. Net-Shaped DNA Nanostructures Designed for Rapid/Sensitive Detection and Potential Inhibition of the SARS-CoV-2 Virus. J. Am. Chem. Soc. 2022 , 145 , 20214–20228. [ Google Scholar ] [ CrossRef ]
  • Inan, H.; Poyraz, M.; Inci, F.; Lifson, M.A.; Baday, M.; Cunningham, B.T.; Demirci, U. Photonic Crystals: Emerging Biosensors and Their Promise for Point-of-Care Applications. Chem. Soc. Rev. 2017 , 46 , 366–388. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Rathnakumar, S.; Bhaskar, S.; Badiya, P.K.; Sivaramakrishnan, V.; Srinivasan, V.; Ramamurthy, S.S. Electrospun PVA Nanofibers Doped with Titania Nanoparticles in Plasmon-Coupled Fluorescence Studies: An Eco-Friendly and Cost-Effective Transition from 2D Nano Thin Films to 1D Nanofibers. MRS Commun. 2023 , 13 , 290–298. [ Google Scholar ] [ CrossRef ]
  • Baumberg, J.J.; Aizpurua, J.; Mikkelsen, M.H.; Smith, D.R. Extreme Nanophotonics from Ultrathin Metallic Gaps. Nat. Mater. 2019 , 18 , 668–678. [ Google Scholar ] [ CrossRef ]
  • Borghei, Y.-S.; Hosseinkhani, S.; Ganjali, M.R. “Plasmonic Nanomaterials”: An Emerging Avenue in Biomedical and Biomedical Engineering Opportunities. J. Adv. Res. 2022 , 39 , 61–71. [ Google Scholar ] [ CrossRef ]
  • Boles, M.A.; Engel, M.; Talapin, D.V. Self-Assembly of Colloidal Nanocrystals: From Intricate Structures to Functional Materials. Chem. Rev. 2016 , 116 , 11220–11289. [ Google Scholar ] [ CrossRef ]
  • Gwo, S.; Chen, H.-Y.; Lin, M.-H.; Sun, L.; Li, X. Nanomanipulation and Controlled Self-Assembly of Metal Nanoparticles and Nanocrystals for Plasmonics. Chem. Soc. Rev. 2016 , 45 , 5672–5716. [ Google Scholar ] [ CrossRef ]
  • Angira, K.; Nshikawa, M.; Mori, T.; Takeya, J.; Shrestha, L.K.; Hill, J.P. Self-assembly as a key player for materials nanoarchitectonics. Sci. Technol. Adv. Mater. 2018 , 20 , 51–95. [ Google Scholar ] [ CrossRef ]
  • Bhaskar, S.; Ramamurthy, S.S. Mobile Phone-Based Picomolar Detection of Tannic Acid on Nd 2 O 3 Nanorod–Metal Thin-Film Interfaces. ACS Appl. Nano Mater. 2019 , 2 , 4613–4625. [ Google Scholar ] [ CrossRef ]
  • Xie, K.-X.; Xu, L.-T.; Zhai, Y.-Y.; Wang, Z.-C.; Chen, M.; Pan, X.-H.; Cao, S.-H.; Li, Y.-Q. The Synergistic Enhancement of Silver Nanocubes and Graphene Oxide on Surface Plasmon-Coupled Emission. Talanta 2019 , 195 , 752–756. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Nguyen, H.; Shih, W.-C. Multiplex Sensing of Lead and Mercury in Drinking Water Using Smartphone Nano-Colorimetry. In Proceedings of the Biophotonics Congress: Optics in the Life Sciences Congress 2019 (BODA, BRAIN, NTM, OMA, OMP) (2019), Bio-Optics: Design and Application 2019, Tucson, AZ, USA, 14–17 April 2019; p. DW1B.6. [ Google Scholar ]
  • Barya, P.; Xiong, Y.; Shepherd, S.; Gupta, R.; Akin, L.D.; Tibbs, J.; Lee, H.K.; Singamaneni, S.; Cunningham, B.T. Photonic-Plasmonic Coupling Enhanced Fluorescence Enabling Digital-Resolution Ultrasensitive Protein Detection. Small 2023 , 19 , 2207239. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Baig, N.; Kammakakam, I.; Falath, W. Nanomaterials: A Review of Synthesis Methods, Properties, Recent Progress, and Challenges. Mater. Adv. 2021 , 2 , 1821–1871. [ Google Scholar ] [ CrossRef ]
  • Ghosh, S.; Li, N.; Xiong, Y.; Ju, Y.-G.; Rathslag, M.P.; Onal, E.G.; Falkiewicz, E.; Kohli, M.; Cunningham, B.T. A Compact Photonic Resonator Absorption Microscope for Point of Care Digital Resolution Nucleic Acid Molecular Diagnostics. Biomed. Opt. Express. BOE 2021 , 12 , 4637–4650. [ Google Scholar ] [ CrossRef ]
  • Liu, L.; Bhaskar, S.; Cunningham, B.T. Hybrid Interfacial Cryosoret Nano-Engineering in Photonic Resonator Interferometric Scattering Microscopy: Insights from Nanoparticles and Nano-Assemblies. Appl. Phys. Lett. 2024 , 124 , 234101. [ Google Scholar ] [ CrossRef ]
  • Purohit, B.; Kumar, A.; Mahato, K.; Chandra, P. Smartphone-Assisted Personalized Diagnostic Devices and Wearable Sensors. Curr. Opin. Biomed. Eng. 2020 , 13 , 42–50. [ Google Scholar ] [ CrossRef ]
  • Allen, C.; Maysinger, D.; Eisenberg, A. Nano-Engineering Block Copolymer Aggregates for Drug Delivery. Colloids Surf. B Biointerfaces 1999 , 16 , 3–27. [ Google Scholar ] [ CrossRef ]
  • Zayats, A.V.; Smolyaninov, I.I.; Maradudin, A.A. Nano-Optics of Surface Plasmon Polaritons. Phys. Rep. 2005 , 408 , 131–314. [ Google Scholar ] [ CrossRef ]
  • Bodnarchuk, M.I.; Kovalenko, M.V.; Heiss, W.; Talapin, D.V. Energetic and Entropic Contributions to Self-Assembly of Binary Nanocrystal Superlattices: Temperature as the Structure-Directing Factor. J. Am. Chem. Soc. 2010 , 132 , 11967–11977. [ Google Scholar ] [ CrossRef ]
  • Grzelczak, M.; Liz-Marzán, L.M.; Klajn, R. Stimuli-Responsive Self-Assembly of Nanoparticles. Chem. Soc. Rev. 2019 , 48 , 1342–1361. [ Google Scholar ] [ CrossRef ]
  • Ozin, G.A.; Hou, K.; Lotsch, B.V.; Cademartiri, L.; Puzzo, D.P.; Scotognella, F.; Ghadimi, A.; Thomson, J. Nanofabrication by Self-Assembly. Mater. Today 2009 , 12 , 12–23. [ Google Scholar ] [ CrossRef ]
  • Čižmár, T.; Romero, L.C.D.; Dholakia, K.; Andrews, D.L. Multiple Optical Trapping and Binding: New Routes to Self-Assembly. J. Phys. B At. Mol. Opt. Phys. 2010 , 43 , 102001. [ Google Scholar ] [ CrossRef ]
  • Haldar, A.; Pal, S.B.; Roy, B.; Gupta, S.D.; Banerjee, A. Self-Assembly of Microparticles in Stable Ring Structures in an Optical Trap. Phys. Rev. A 2012 , 85 , 033832. [ Google Scholar ] [ CrossRef ]
  • Aoki, K.; Miyazaki, H.T.; Hirayama, H.; Inoshita, K.; Baba, T.; Sakoda, K.; Shinya, N.; Aoyagi, Y. Microassembly of Semiconductor Three-Dimensional Photonic Crystals. Nat. Mater. 2003 , 2 , 117–121. [ Google Scholar ] [ CrossRef ]
  • Rao, A.; Roy, S.; Jain, V.; Pillai, P.P. Nanoparticle Self-Assembly: From Design Principles to Complex Matter to Functional Materials. ACS Appl. Mater. Interfaces 2022 , 15 , 25248–25274. [ Google Scholar ] [ CrossRef ]
  • Li, Z.; Fan, Q.; Yin, Y. Colloidal Self-Assembly Approaches to Smart Nanostructured Materials. Chem. Rev. 2022 , 122 , 4976–5067. [ Google Scholar ] [ CrossRef ]
  • Ji, D.-D.; Wu, M.-X.; Ding, S.-N. Photonic Crystal Barcodes Assembled from Dendritic Silica Nanoparticles for the Multiplex Immunoassays of Ovarian Cancer Biomarkers. Anal. Methods 2022 , 14 , 298–305. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Wang, X.; Li, J.; Shen, Y.; Xie, A. An Assembled Ordered W 18 O 49 Nanowire Film with High SERS Sensitivity and Stability for the Detection of RB. Appl. Surf. Sci. 2020 , 504 , 144073. [ Google Scholar ] [ CrossRef ]
  • Chang, W.-S.; Willingham, B.A.; Slaughter, L.S.; Khanal, B.P.; Vigderman, L.; Zubarev, E.R.; Link, S. Low Absorption Losses of Strongly Coupled Surface Plasmons in Nanoparticle Assemblies. Proc. Natl. Acad. Sci. USA 2011 , 108 , 19879–19884. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Bhaskar, S.; Moronshing, M.; Srinivasan, V.; Badiya, P.K.; Subramaniam, C.; Ramamurthy, S.S. Silver Soret Nanoparticles for Femtomolar Sensing of Glutathione in a Surface Plasmon-Coupled Emission Platform. ACS Appl. Nano Mater. 2020 , 3 , 4329–4341. [ Google Scholar ] [ CrossRef ]
  • Bhaskar, S.; Das, P.; Srinivasan, V.; Bhaktha, S.B.N.; Ramamurthy, S.S. Plasmonic-Silver Sorets and Dielectric-Nd 2 O 3 Nanorods for Ultrasensitive Photonic Crystal-Coupled Emission. Mater. Res. Bull. 2022 , 145 , 111558. [ Google Scholar ] [ CrossRef ]
  • Moronshing, M.; Subramaniam, C. Room Temperature, Multiphasic Detection of Explosives, and Volatile Organic Compounds Using Thermodiffusion Driven Soret Colloids. ACS Sustain. Chem. Eng. 2018 , 6 , 9470–9479. [ Google Scholar ] [ CrossRef ]
  • Rai, A.; Bhaskar, S.; Ganesh, K.M.; Ramamurthy, S.S. Engineering of Coherent Plasmon Resonances from Silver Soret Colloids, Graphene Oxide and Nd 2 O 3 Nanohybrid Architectures Studied in Mobile Phone-Based Surface Plasmon-Coupled Emission Platform. Mater. Lett. 2021 , 304 , 130632. [ Google Scholar ] [ CrossRef ]
  • Bhaskar, S.; Jha, P.; Subramaniam, C.; Ramamurthy, S.S. Multifunctional Hybrid Soret Nanoarchitectures for Mobile Phone-Based Picomolar Cu 2+ Ion Sensing and Dye Degradation Applications. Phys. E Low-Dimens. Syst. Nanostructures 2021 , 132 , 114764. [ Google Scholar ] [ CrossRef ]
  • Bhaskar, S.; Das, P.; Moronshing, M.; Rai, A.; Subramaniam, C.; Bhaktha, S.B.N.; Ramamurthy, S.S. Photoplasmonic Assembly of Dielectric-Metal, Nd 2 O 3 -Gold Soret Nanointerfaces for Dequenching the Luminophore Emission. Nanophotonics 2021 , 10 , 3417–3431. [ Google Scholar ] [ CrossRef ]
  • Hou, S.; Bai, L.; Lu, D.; Duan, H. Interfacial Colloidal Self-Assembly for Functional Materials. Acc. Chem. Res. 2023 , 56 , 740–751. [ Google Scholar ] [ CrossRef ]
  • Bishop, K.J.M.; Wilmer, C.E.; Soh, S.; Grzybowski, B.A. Nanoscale Forces and Their Uses in Self-Assembly. Small 2009 , 5 , 1600–1630. [ Google Scholar ] [ CrossRef ]
  • Deng, K.; Luo, Z.; Tan, L.; Quan, Z. Self-Assembly of Anisotropic Nanoparticles into Functional Superstructures. Chem. Soc. Rev. 2020 , 49 , 6002–6038. [ Google Scholar ] [ CrossRef ]
  • Rai, A.; Bhaskar, S.; Ganesh, K.M.; Ramamurthy, S.S. Hottest Hotspots from the Coldest Cold: Welcome to Nano 4.0. ACS Appl. Nano Mater. 2022 , 5 , 12245–12264. [ Google Scholar ] [ CrossRef ]
  • Chakrabortty, S.; Guchhait, A.; Ong, X.; Mishra, N.; Wu, W.-Y.; Jhon, M.H.; Chan, Y. Facet to Facet Linking of Shape Anisotropic Inorganic Nanocrystals with Site Specific and Stoichiometric Control. Nano Lett. 2016 , 16 , 6431–6436. [ Google Scholar ] [ CrossRef ]
  • Sadtler, B.; Demchenko, D.O.; Zheng, H.; Hughes, S.M.; Merkle, M.G.; Dahmen, U.; Wang, L.-W.; Alivisatos, A.P. Selective Facet Reactivity during Cation Exchange in Cadmium Sulfide Nanorods. J. Am. Chem. Soc. 2009 , 131 , 5285–5293. [ Google Scholar ] [ CrossRef ]
  • Beberwyck, B.J.; Surendranath, Y.; Alivisatos, A.P. Cation Exchange: A Versatile Tool for Nanomaterials Synthesis. J. Phys. Chem. C 2013 , 117 , 19759–19770. [ Google Scholar ] [ CrossRef ]
  • Gupta, S.; Wu, W.-Y.; Chakrabortty, S.; Li, M.; Wang, Y.; Ong, X.; Chan, Y. Hierarchical Multicomponent Nanoheterostructures via Facet-to-Facet Attachment of Anisotropic Semiconductor Nanoparticles. Chem. Mater. 2017 , 29 , 9075–9083. [ Google Scholar ] [ CrossRef ]
  • Arora, D.; Lian, J.; Xu, Y.; Wu, W.-Y.; Chan, Y. Branched Heterostructured Semiconductor Nanocrystals with Various Branch Orders via a Facet-to-Facet Linking Process. ACS Nano 2020 , 14 , 10337–10345. [ Google Scholar ] [ CrossRef ]
  • Arora, D.; Tan, H.R.; Wu, W.-Y.; Chan, Y. 2D-Oriented Attachment of 1D Colloidal Semiconductor Nanocrystals via an Etchant. Nano Lett. 2022 , 22 , 942–947. [ Google Scholar ] [ CrossRef ]
  • Singh, A.; Singh, A.; Ciston, J.; Bustillo, K.; Nordlund, D.; Milliron, D.J. Synergistic Role of Dopants on the Morphology of Alloyed Copper Chalcogenide Nanocrystals. J. Am. Chem. Soc. 2015 , 137 , 6464–6467. [ Google Scholar ] [ CrossRef ]
  • Son, D.H.; Hughes, S.M.; Yin, Y.; Alivisatos, A.P. Cation exchange reactions in ionic nanocrystals. Science 2004 , 306 , 1009–1012. [ Google Scholar ] [ CrossRef ]
  • He, J.; Reyner, C.J.; Liang, B.L.; Nunna, K.; Huffaker, D.L.; Pavarelli, N.; Gradkowski, K.; Ochalski, T.J.; Huyet, G.; Dorogan, V.G.; et al. Band Alignment Tailoring of InAs1−xSbx/GaAs Quantum Dots: Control of Type I to Type II Transition. Nano Lett. 2010 , 10 , 3052–3056. [ Google Scholar ] [ CrossRef ]
  • Tatebayashi, J.; Liang, B.L.; Laghumavarapu, R.B.; Bussian, D.A.; Htoon, H.; Klimov, V.; Balakrishnan, G.; Dawson, L.R.; Huffaker, D.L. Time-Resolved Photoluminescence of Type-II Ga(As)Sb/GaAs Quantum Dots Embedded in an InGaAs Quantum Well. Nanotechnology 2008 , 19 , 295704. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Kawazu, T.; Noda, T.; Mano, T.; Sakuma, Y.; Sakaki, H. Growth and Optical Properties of GaSb/GaAs Type-II Quantum Dots with and without Wetting Layer. Jpn. J. Appl. Phys. 2015 , 54 , 4DH01. [ Google Scholar ] [ CrossRef ]
  • Hayne, M.; Maes, J.; Bersier, S.; Moshchalkov, V.V.; Schliwa, A.; Müller-Kirsch, L.; Kapteyn, C.; Heitz, R.; Bimberg, D. Electron Localization by Self-Assembled GaSb/GaAs Quantum Dots. Appl. Phys. Lett. 2003 , 82 , 4355–4357. [ Google Scholar ] [ CrossRef ]
  • Borsdorf, L.; Herkert, L.; Bäumer, N.; Rubert, L.; Soberats, B.; Korevaar, P.A.; Bourque, C.; Gatsogiannis, C.; Fernández, G. Pathway-Controlled Aqueous Supramolecular Polymerization via Solvent-Dependent Chain Conformation Effects. J. Am. Chem. Soc. 2023 , 145 , 8882–8895. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Sánchez-Iglesias, A.; Grzelczak, M.; Altantzis, T.; Goris, B.; Pérez-Juste, J.; Bals, S.; Van Tendeloo, G.; Donaldson, S.H.; Chmelka, B.F.; Israelachvili, J.N.; et al. Hydrophobic Interactions Modulate Self-Assembly of Nanoparticles. ACS Nano 2012 , 6 , 11059–11065. [ Google Scholar ] [ CrossRef ]
  • Zhou, S.; Zhang, S.; Li, H.; Sun, D.; Zhang, J.; Xin, X. Solvent-Induced Self-Assembly of Copper Nanoclusters for White Light Emitting Diodes. ACS Appl. Nano Mater. 2021 , 4 , 10911–10920. [ Google Scholar ] [ CrossRef ]
  • Yang, K.; Yao, X.; Liu, B.; Ren, B. Metallic Plasmonic Array Structures: Principles, Fabrications, Properties, and Applications. Adv. Mater. 2021 , 33 , 2007988. [ Google Scholar ] [ CrossRef ]
  • Mayer, M.; Schnepf, M.J.; König, T.A.F.; Fery, A. Colloidal Self-Assembly Concepts for Plasmonic Metasurfaces. Adv. Opt. Mater. 2019 , 7 , 1800564. [ Google Scholar ] [ CrossRef ]
  • Cai, D.; Li, J.; Ma, Z.; Gan, Z.; Shao, Y.; Xing, Q.; Tan, R.; Dong, X.-H. Effect of Molecular Architecture and Symmetry on Self-Assembly: A Quantitative Revisit Using Discrete ABA Triblock Copolymers. ACS Macro Lett. 2022 , 11 , 555–561. [ Google Scholar ] [ CrossRef ]
  • Gao, B.; Rozin, M.J.; Tao, A.R. Plasmonic Nanocomposites: Polymer-Guided Strategies for Assembling Metal Nanoparticles. Nanoscale 2013 , 5 , 5677–5691. [ Google Scholar ] [ CrossRef ]
  • Ianiro, A.; Wu, H.; van Rijt, M.M.J.; Vena, M.P.; Keizer, A.D.A.; Esteves, A.C.C.; Tuinier, R.; Friedrich, H.; Sommerdijk, N.A.J.M.; Patterson, J.P. Liquid–Liquid Phase Separation during Amphiphilic Self-Assembly. Nat. Chem. 2019 , 11 , 320–328. [ Google Scholar ] [ CrossRef ]
  • Huanga, X.; Liu, Y.; Barr, J.; Song, J.; He, Z.; Wang, Y.; Nie, Z.; Xiong, Y.; Chen, X. Controllable Self-Assembled Plasmonic Vesicle-Based Three-Dimensional SERS Platform for Picomolar Detection of Hydrophobic Contaminants. Nanoscale 2018 , 10 , 13202–13211. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Li, C.; Xu, Y.; Li, X.; Ye, Z.; Yao, C.; Chen, Q.; Zhang, Y.; Bell, S.E.J. Unexpected Dual Action of Cetyltrimethylammonium Bromide (CTAB) in the Self-Assembly of Colloidal Nanoparticles at Liquid–Liquid Interfaces. Adv. Mater. Interfaces 2020 , 7 , 2000391. [ Google Scholar ] [ CrossRef ]
  • Piloni, A.; Walther, A.; Stenzel, M.H. Compartmentalized Nanoparticles in Aqueous Solution through Hierarchical Self-Assembly of Triblock Glycopolymers. Polym. Chem. 2018 , 9 , 4132–4142. [ Google Scholar ] [ CrossRef ]
  • Liu, Y.; Fu, W.; Xu, Z.; Zhang, L.; Sun, T.; Du, M.; Kang, X.; Xiao, S.; Zhou, C.; Gong, M.; et al. pH-Driven Reversible Assembly and Disassembly of Colloidal Gold Nanoparticles. Front. Chem. 2021 , 9 , 675491. [ Google Scholar ] [ CrossRef ]
  • Liu, B.; Zhang, J.; Li, L. Metal–DNA Coordination-Driven Self-Assembly: A Conceptual Methodology to Expand the Repertoire of DNA Nanobiotechnology. Chem.—A Eur. J. 2019 , 25 , 13452–13457. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Liu, B.; Liu, J. Interface-Driven Hybrid Materials Based on DNA-Functionalized Gold Nanoparticles. Matter 2019 , 1 , 825–847. [ Google Scholar ] [ CrossRef ]
  • Wang, G.; Zhang, Y.; Liang, X.; Takarada, T.; Maeda, M. Regioselective DNA Modification and Directed Self-Assembly of Triangular Gold Nanoplates. Nanomaterials 2019 , 9 , 581. [ Google Scholar ] [ CrossRef ]
  • Ren, S.; Wang, J.; Song, C.; Li, Q.; Yang, Y.; Teng, N.; Su, S.; Zhu, D.; Huang, W.; Chao, J.; et al. Single-Step Organization of Plasmonic Gold Metamaterials with Self-Assembled DNA Nanostructures. Research 2019 , 2019 , 7403580. [ Google Scholar ] [ CrossRef ]
  • Urban, M.J.; Dutta, P.K.; Wang, P.; Duan, X.; Shen, X.; Ding, B.; Ke, Y.; Liu, N. Plasmonic Toroidal Metamolecules Assembled by DNA Origami. J. Am. Chem. Soc. 2016 , 138 , 5495–5498. [ Google Scholar ] [ CrossRef ]
  • Ma, L.; Liu, Y.; Han, C.; Movsesyan, A.; Li, P.; Li, H.; Tang, P.; Yuan, Y.; Jiang, S.; Ni, W.; et al. DNA-Assembled Chiral Satellite-Core Nanoparticle Superstructures: Two-State Chiral Interactions from Dynamic and Static Conformations. Nano Lett. 2022 , 22 , 4784–4791. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Alexander, C. Self-Assembly of Biopolymers—Recent Progress and Future Prospects. Faraday Discuss. 2013 , 166 , 449. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Sugawara-Narutaki, A.; Kamiya, Y. Designer Biopolymers: Self-Assembling Proteins and Nucleic Acids. Int. J. Mol. Sci. 2020 , 21 , 3276. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Ofir, Y.; Samanta, B.; Rotello, V.M. Polymer and Biopolymer Mediated Self-Assembly of Gold Nanoparticles. Chem. Soc. Rev. 2008 , 37 , 1814. [ Google Scholar ] [ CrossRef ]
  • Lin, Y.; Chapman, R.; Stevens, M.M. Integrative Self-Assembly of Graphene Quantum Dots and Biopolymers into a Versatile Biosensing Toolkit. Adv. Funct. Mater. 2015 , 25 , 3183–3192. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Peller, M.; Böll, K.; Zimpel, A.; Wuttke, S. Metal–Organic Framework Nanoparticles for Magnetic Resonance Imaging. Inorg. Chem. Front. 2018 , 5 , 1760–1779. [ Google Scholar ] [ CrossRef ]
  • Xu, J.; Wang, J.; Ye, J.; Jiao, J.; Liu, Z.; Zhao, C.; Li, B.; Fu, Y. Metal-Coordinated Supramolecular Self-Assemblies for Cancer Theranostics. Adv. Sci. 2021 , 8 , 2101101. [ Google Scholar ] [ CrossRef ]
  • Grzelczak, M.; Vermant, J.; Furst, E.M.; Liz-Marzán, L.M. Directed Self-Assembly of Nanoparticles. ACS Nano 2010 , 4 , 3591–3605. [ Google Scholar ] [ CrossRef ]
  • Bi, Y.; Wang, Z.; Liu, T.; Sun, D.; Godbert, N.; Li, H.; Hao, J.; Xin, X. Supramolecular Chirality from Hierarchical Self-Assembly of Atomically Precise Silver Nanoclusters Induced by Secondary Metal Coordination. ACS Nano 2021 , 15 , 15910–15919. [ Google Scholar ] [ CrossRef ]
  • Mahato, P.; Shekhar, S.; Agrawal, S.; Pramanik, S.; Mukherjee, S. Assembly-Induced Emission in Mercaptosuccinic Acid-Templated Silver Nanoclusters: Metal Ion Selectivity and pH Sensitivity. ACS Appl. Nano Mater. 2022 , 5 , 7571–7579. [ Google Scholar ] [ CrossRef ]
  • Su, J.; Huang, X.; Yang, M. Self-Limiting Assembly of Au Nanoparticles Induced by Localized Dynamic Metal-Phenolic Interactions. Eur. J. Inorg. Chem. 2020 , 2020 , 4477–4482. [ Google Scholar ] [ CrossRef ]
  • Wu, B.; Liu, D.; Mubeen, S.; Chuong, T.T.; Moskovits, M.; Stucky, G.D. Anisotropic Growth of TiO2 onto Gold Nanorods for Plasmon-Enhanced Hydrogen Production from Water Reduction. J. Am. Chem. Soc. 2016 , 138 , 1114–1117. [ Google Scholar ] [ CrossRef ]
  • Chen, S.; Guo, C.X.; Zhao, Q.; Lu, X. One-Pot Synthesis of CO2-Responsive Magnetic Nanoparticles with Switchable Hydrophilicity. Chem.—A Eur. J. 2014 , 20 , 14057–14062. [ Google Scholar ] [ CrossRef ]
  • Fan, W.; Tong, X.; Farnia, F.; Yu, B.; Zhao, Y. CO2-Responsive Polymer Single-Chain Nanoparticles and Self-Assembly for Gas-Tunable Nanoreactors. Chem. Mater. 2017 , 29 , 5693–5701. [ Google Scholar ] [ CrossRef ]
  • Gentili, D.; Ori, G. Reversible Assembly of Nanoparticles: Theory, Strategies and Computational Simulations. Nanoscale 2022 , 14 , 14385–14432. [ Google Scholar ] [ CrossRef ]
  • Fu, Y.; Zhao, S.; Chen, W.; Zhang, Q.; Chai, Y. Self-Assembly of Nanoparticles with Stimulated Responses at Liquid Interfaces. Nano Today 2024 , 54 , 102073. [ Google Scholar ] [ CrossRef ]
  • Sahle, F.F.; Gulfam, M.; Lowe, T.L. Design Strategies for Physical-Stimuli-Responsive Programmable Nanotherapeutics. Drug Discov. Today 2018 , 23 , 992–1006. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Merino, E.; Ribagorda, M. Control over Molecular Motion Using the Cis–Trans Photoisomerization of the Azo Group. Beilstein J. Org. Chem. 2012 , 8 , 1071–1090. [ Google Scholar ] [ CrossRef ]
  • Huebner, D.; Rossner, C.; Vana, P. Light-Induced Self-Assembly of Gold Nanoparticles with a Photoresponsive Polymer Shell. Polymer 2016 , 107 , 503–508. [ Google Scholar ] [ CrossRef ]
  • Bian, T.; Chu, Z.; Klajn, R. The Many Ways to Assemble Nanoparticles Using Light. Adv. Mater. 2020 , 32 , 1905866. [ Google Scholar ] [ CrossRef ]
  • Zhang, L.; Dai, L.; Rong, Y.; Liu, Z.; Tong, D.; Huang, Y.; Chen, T. Light-Triggered Reversible Self-Assembly of Gold Nanoparticle Oligomers for Tunable SERS. Langmuir 2015 , 31 , 1164–1171. [ Google Scholar ] [ CrossRef ]
  • Caillosse, E.; Zaier, M.; Mezghani, M.; Hajjar-Garreau, S.; Vidal, L.; Lougnot, D.; Balan, L. Photo-Induced Self-Assembly of Silver Nanoparticles for Rapid Generation of First and Second Surface Mirrors. ACS Appl. Nano Mater. 2020 , 3 , 6531–6540. [ Google Scholar ] [ CrossRef ]
  • He, H.; Feng, M.; Chen, Q.; Zhang, X.; Zhan, H. Light-Induced Reversible Self-Assembly of Gold Nanoparticles Surface-Immobilized with Coumarin Ligands. Angew. Chem. Int. Ed. Engl. 2016 , 55 , 936–940. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Nieminen, T.A.; Knöner, G.; Heckenberg, N.R.; Rubinsztein-Dunlop, H. Physics of Optical Tweezers. Methods Cell Biol. 2007 , 82 , 207–236. [ Google Scholar ] [ PubMed ]
  • Svoboda, K.; Block, S.M. Optical Trapping of Metallic Rayleigh Particles. Opt. Lett. 1994 , 19 , 930. [ Google Scholar ] [ CrossRef ]
  • Zelenina, A.S.; Quidant, R.; Badenes, G.; Nieto-Vesperinas, M. Tunable Optical Sorting and Manipulation of Nanoparticles via Plasmon Excitation. Opt. Lett. 2006 , 31 , 2054. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Blázquez-Castro, A. Optical Tweezers: Phototoxicity and Thermal Stress in Cells and Biomolecules. Micromachines 2019 , 10 , 507. [ Google Scholar ] [ CrossRef ]
  • Tan, H.; Hu, H.; Huang, L.; Qian, K. Plasmonic Tweezers for Optical Manipulation and Biomedical Applications. Analyst 2020 , 145 , 5699–5712. [ Google Scholar ] [ CrossRef ]
  • Zaman, M.A.; Hesselink, L. Dynamically Controllable Plasmonic Tweezers Using C-Shaped Nano-Engravings. Appl. Phys. Lett. 2022 , 121 , 181108. [ Google Scholar ] [ CrossRef ]
  • Mohapatra, J.; Elkins, J.; Xing, M.; Guragain, D.; Mishra, S.R.; Liu, J.P. Magnetic-Field-Induced Self-Assembly of FeCo/CoFe 2 O 4 Core/Shell Nanoparticles with Tunable Collective Magnetic Properties. Nanoscale 2021 , 13 , 4519–4529. [ Google Scholar ] [ CrossRef ]
  • Mehdizadeh Taheri, S.; Michaelis, M.; Friedrich, T.; Förster, B.; Drechsler, M.; Römer, F.M.; Bösecke, P.; Narayanan, T.; Weber, B.; Rehberg, I.; et al. Self-Assembly of Smallest Magnetic Particles. Proc. Natl. Acad. Sci. USA 2015 , 112 , 14484–14489. [ Google Scholar ] [ CrossRef ]
  • Gleich, B.; Weizenecker, J. Tomographic Imaging Using the Nonlinear Response of Magnetic Particles. Nature 2005 , 435 , 1214–1217. [ Google Scholar ] [ CrossRef ]
  • Chen, M.; Niu, X.; Yu, P.; Li, Q.; Li, Y.; Li, X.; Adnan, K. Numerical Investigation of Magnetic-Field Induced Self-Assembly of Nonmagnetic Particles in Magnetic Fluids. J. Fluids Struct. 2020 , 97 , 103008. [ Google Scholar ] [ CrossRef ]
  • Singh, G.; Chan, H.; Udayabhaskararao, T.; Gelman, E.; Peddis, D.; Baskin, A.; Leitus, G.; Král, P.; Klajn, R. Magnetic Field-Induced Self-Assembly of Iron Oxide Nanocubes. Faraday Discuss. 2015 , 181 , 403–421. [ Google Scholar ] [ CrossRef ]
  • Jung, Y.; Kim, H.; Cheong, H.-K.; Lim, Y. Magnetic Control of Self-Assembly and Disassembly in Organic Materials. Nat. Commun. 2023 , 14 , 3081. [ Google Scholar ] [ CrossRef ]
  • Abd Rahman, N.; Ibrahim, F.; Yafouz, B. Dielectrophoresis for Biomedical Sciences Applications: A Review. Sensors 2017 , 17 , 449. [ Google Scholar ] [ CrossRef ]
  • Zaman, M.A.; Padhy, P.; Hansen, P.C.; Hesselink, L. Dielectrophoresis-Assisted Plasmonic Trapping of Dielectric Nanoparticles. Phys. Rev. A 2017 , 95 , 23840. [ Google Scholar ] [ CrossRef ]
  • Zaman, M.A.; Padhy, P.; Wu, M.; Ren, W.; Jensen, M.A.; Davis, R.W.; Hesselink, L. Controlled Transport of Individual Microparticles Using Dielectrophoresis. Langmuir 2023 , 39 , 101–110. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Chiou, P.-Y.; Chang., Z.; Wu, M.C. Droplet Manipulation with Light on Optoelectrowetting Device. J. Microelectromech. Syst. 2008 , 17 , 133–138. [ Google Scholar ] [ CrossRef ]
  • Wu, M.C. Optoelectronic Tweezers—An Optofluidic Platform for Digital Cell Biology. In Proceedings of the 2019 International Conference on Optical MEMS and Nanophotonics (OMN), Daejeon, Republic of Korea, 28 July–1 August 2019; pp. 94–95. [ Google Scholar ]
  • Zhang, S.; Xu, B.; Elsayed, M.; Nan, F.; Liang, W.; Valley, J.K.; Liu, L.; Huang, Q.; Wu, M.C.; Wheeler, A.R. Optoelectronic Tweezers: A Versatile Toolbox for Nano-/Micro-Manipulation. Chem. Soc. Rev. 2022 , 51 , 9203–9242. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Liu, J.; Zheng, M.; Xiong, Z.; Li, Z.-Y. 3D Dynamic Motion of a Dielectric Micro-Sphere within Optical Tweezers. OEA 2021 , 4 , 200015. [ Google Scholar ] [ CrossRef ]
  • Zaman, M.A.; Padhy, P.; Cheng, Y.-T.; Galambos, L.; Hesselink, L. Optoelectronic Tweezers with a Non-Uniform Background Field. Appl. Phys. Lett. 2020 , 117 , 171102. [ Google Scholar ] [ CrossRef ]
  • Sebastián-Vicente, C.; Remacha-Sanz, P.; Elizechea-López, E.; García-Cabañes, Á.; Carrascosa, M. Combinatorial Nanoparticle Patterns Assembled by Photovoltaic Optoelectronic Tweezers. Appl. Phys. Lett. 2022 , 121 , 121104. [ Google Scholar ] [ CrossRef ]
  • Atifi, S.; Mirvakili, M.-N.; Williams, C.A.; Bay, M.M.; Vignolini, S.; Hamad, W.Y. Fast Self-Assembly of Scalable Photonic Cellulose Nanocrystals and Hybrid Films via Electrophoresis. Adv. Mater. 2022 , 34 , e2109170. [ Google Scholar ] [ CrossRef ]
  • Montelongo, Y.; Sikdar, D.; Ma, Y.; McIntosh, A.J.S.; Velleman, L.; Kucernak, A.R.; Edel, J.B.; Kornyshev, A.A. Electrotunable Nanoplasmonic Liquid Mirror. Nat. Mater. 2017 , 16 , 1127–1135. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Nie, Z.; Petukhova, A.; Kumacheva, E. Properties and Emerging Applications of Self-Assembled Structures Made from Inorganic Nanoparticles. Nat. Nanotech 2010 , 5 , 15–25. [ Google Scholar ] [ CrossRef ]
  • Balasubramaniam, S.; Pothayee, N.; Lin, Y.; House, M.; Woodward, R.C.; St. Pierre, T.G.; Davis, R.M.; Riffle, J.S. Poly(N-Isopropylacrylamide)-Coated Superparamagnetic Iron Oxide Nanoparticles: Relaxometric and Fluorescence Behavior Correlate to Temperature-Dependent Aggregation. Chem. Mater. 2011 , 23 , 3348–3356. [ Google Scholar ] [ CrossRef ]
  • Liu, Y.; Han, X.; He, L.; Yin, Y. Thermoresponsive Assembly of Charged Gold Nanoparticles and Their Reversible Tuning of Plasmon Coupling. Angew. Chem. Int. Ed. 2012 , 51 , 6373–6377. [ Google Scholar ] [ CrossRef ]
  • Lewandowski, W.; Fruhnert, M.; Mieczkowski, J.; Rockstuhl, C.; Górecka, E. Dynamically Self-Assembled Silver Nanoparticles as a Thermally Tunable Metamaterial. Nat. Commun. 2015 , 6 , 6590. [ Google Scholar ] [ CrossRef ]
  • Cheerala, V.S.K.; Ganesh, K.M.; Bhaskar, S.; Ramamurthy, S.S.; Neelakantan, S.C. Smartphone-Based Attomolar Cyanide Ion Sensing Using Au-Graphene Oxide Cryosoret Nanoassembly and Benzoxazolium-Based Fluorophore in a Surface Plasmon-Coupled Enhanced Fluorescence Interface. Langmuir 2023 , 39 , 7939–7957. [ Google Scholar ] [ CrossRef ]
  • Bhaskar, S. Biosensing Technologies: A Focus Review on Recent Advancements in Surface Plasmon Coupled Emission. Micromachines 2023 , 14 , 574. [ Google Scholar ] [ CrossRef ]
  • Bhaskar, S.; Ramamurthy, S.S. High Refractive Index Dielectric TiO 2 and Graphene Oxide as Salient Spacers for >300-Fold Enhancements. In Proceedings of the 2021 IEEE International Conference on Nanoelectronics, Nanophotonics, Nanomaterials, Nanobioscience & Nanotechnology (5NANO), Kottayam, India, 29–30 April 2021; pp. 1–6. [ Google Scholar ]
  • Bhaskar, S.; Srinivasan, V.; Ramamurthy, S.S. Nd 2 O 3 -Ag Nanostructures for Plasmonic Biosensing, Antimicrobial, and Anticancer Applications. ACS Appl. Nano Mater. 2023 , 6 , 1129–1145. [ Google Scholar ] [ CrossRef ]
  • Cunningham, B.T.; Zhang, M.; Zhuo, Y.; Kwon, L.; Race, C. Recent Advances in Biosensing With Photonic Crystal Surfaces: A Review. IEEE Sens. J. 2016 , 16 , 3349–3366. [ Google Scholar ] [ CrossRef ]
  • Kuang, M.; Wang, J.; Jiang, L. Bio-Inspired Photonic Crystals with Superwettability. Chem. Soc. Rev. 2016 , 45 , 6833–6854. [ Google Scholar ] [ CrossRef ]
  • Duan, H.; Wang, D.; Li, Y. Green Chemistry for Nanoparticle Synthesis. Chem. Soc. Rev. 2015 , 44 , 5778–5792. [ Google Scholar ] [ CrossRef ]
  • Zhao, L.; Wang, Y.; Zhao, X.; Deng, Y.; Li, Q.; Xia, Y. Green Preparation of Ag-Au Bimetallic Nanoparticles Supported on Graphene with Alginate for Non-Enzymatic Hydrogen Peroxide Detection. Nanomaterials 2018 , 8 , 507. [ Google Scholar ] [ CrossRef ]
  • Karbalaei Akbari, M.; Hu, J.; Verpoort, F.; Zhuiykov, S. Bioinspired Patterned Photonic Junctions for Plasmon-Enhanced Metal Photoluminescence and Fluorescence: Design of Optical Cavities for near-Infrared Electronics. Mater. Today Energy 2022 , 26 , 101003. [ Google Scholar ] [ CrossRef ]
  • Egbuna, C.; Parmar, V.K.; Jeevanandam, J.; Ezzat, S.M.; Patrick-Iwuanyanwu, K.C.; Adetunji, C.O.; Khan, J.; Onyeike, E.N.; Uche, C.Z.; Akram, M.; et al. Toxicity of Nanoparticles in Biomedical Application: Nanotoxicology. J. Toxicol. 2021 , 2021 , e9954443. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Cui, L.; Zhang, L.; Zeng, H. Distance-Dependent Fluorescence Resonance Energy Transfer Enhancement on Nanoporous Gold. Nanomaterials 2021 , 11 , 2927. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • He, Z.; Li, F.; Zuo, P.; Tian, H. Principles and Applications of Resonance Energy Transfer Involving Noble Metallic Nanoparticles. Materials 2023 , 16 , 3083. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Hou, S.; Chen, Y.; Lu, D.; Xiong, Q.; Lim, Y.; Duan, H. A Self-Assembled Plasmonic Substrate for Enhanced Fluorescence Resonance Energy Transfer. Adv. Mater. 2020 , 32 , 1906475. [ Google Scholar ] [ CrossRef ]
  • Zheng, D.; Zhang, S.; Deng, Q.; Kang, M.; Nordlander, P.; Xu, H. Manipulating Coherent Plasmon–Exciton Interaction in a Single Silver Nanorod on Monolayer WSe 2 . Nano Lett. 2017 , 17 , 3809–3814. [ Google Scholar ] [ CrossRef ]
  • Penzo, E.; Loiudice, A.; Barnard, E.S.; Borys, N.J.; Jurow, M.J.; Lorenzon, M.; Rajzbaum, I.; Wong, E.K.; Liu, Y.; Schwartzberg, A.M.; et al. Long-Range Exciton Diffusion in Two-Dimensional Assemblies of Cesium Lead Bromide Perovskite Nanocrystals. ACS Nano 2020 , 14 , 6999–7007. [ Google Scholar ] [ CrossRef ]
  • Zhang, P.; Guo, Z.; Ullah, S.; Melagraki, G.; Afantitis, A.; Lynch, I. Nanotechnology and Artificial Intelligence to Enable Sustainable and Precision Agriculture. Nat. Plants 2021 , 7 , 864–876. [ Google Scholar ] [ CrossRef ]
  • Naik, G.G.; Jagtap, V.A. Two Heads Are Better than One: Unravelling the Potential Impact of Artificial Intelligence in Nanotechnology. Nano Trans. Med. 2024 , 3 , 100041. [ Google Scholar ] [ CrossRef ]
  • Masson, J.-F.; Biggins, J.S.; Ringe, E. Machine Learning for Nanoplasmonics. Nat. Nanotechnol. 2023 , 18 , 111–123. [ Google Scholar ] [ CrossRef ]
  • Nandipati, M.; Fatoki, O.; Desai, S. Bridging Nanomanufacturing and Artificial Intelligence—A Comprehensive Review. Materials 2024 , 17 , 1621. [ Google Scholar ] [ CrossRef ]
  • Chugh, V.; Basu, A.; Kaushik, A.; Manshu; Bhansali, S.; Basu, A.K. Employing Nano-Enabled Artificial Intelligence (AI)-Based Smart Technologies for Prediction, Screening, and Detection of Cancer. Nanoscale 2024 , 16 , 5458–5486. [ Google Scholar ] [ CrossRef ]
  • Brown, K.A.; Brittman, S.; Maccaferri, N.; Jariwala, D.; Celano, U. Machine Learning in Nanoscience: Big Data at Small Scales. Nano Lett. 2020 , 20 , 2–10. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Adir, O.; Poley, M.; Chen, G.; Froim, S.; Krinsky, N.; Shklover, J.; Shainsky-Roitman, J.; Lammers, T.; Schroeder, A. Integrating Artificial Intelligence and Nanotechnology for Precision Cancer Medicine. Adv. Mater. 2020 , 32 , 1901989. [ Google Scholar ] [ CrossRef ]
  • Pamies, R.; Zhu, K.; Kjøniksen, A.-L.; Nyström, B. Thermal Response of Low Molecular Weight Poly-(N-Isopropylacrylamide) Polymers in Aqueous Solution. Polym. Bull. 2009 , 62 , 487–502. [ Google Scholar ] [ CrossRef ]
  • Singamaneni, S.; Bliznyuk, V.N.; Binek, C.; Tsymbal, E.Y. Magnetic Nanoparticles: Recent Advances in Synthesis, Self-Assembly and Applications. J. Mater. Chem. 2011 , 21 , 16819. [ Google Scholar ] [ CrossRef ]
  • Zhang, Y.; Xiao, X.; Zhou, J.; Wang, L.; Li, Z.; Li, L.; Shi, L.; Chan, C.-M. Re-Assembly Behaviors of Polystyrene-b-Poly(Acrylic Acid) Micelles. Polymer 2009 , 50 , 6166–6171. [ Google Scholar ] [ CrossRef ]
  • Sui, B.; Zhu, Y.; Jiang, X.; Wang, Y.; Zhang, N.; Lu, Z.; Yang, B.; Li, Y. Recastable Assemblies of Carbon Dots into Mechanically Robust Macroscopic Materials. Nat. Commun. 2023 , 14 , 6782. [ Google Scholar ] [ CrossRef ]
  • Ornelas-Hernández, L.F.; Garduno-Robles, A.; Zepeda-Moreno, A. A Brief Review of Carbon Dots–Silica Nanoparticles Synthesis and Their Potential Use as Biosensing and Theragnostic Applications. Nanoscale Res. Lett. 2022 , 17 , 56. [ Google Scholar ] [ CrossRef ]
  • Habteyes, T.G.; Westphal, E.R.; Plackowski, K.M.; Kotula, P.G.; Meyerson, M.L.; White, S.L.; Corbin, W.C.; Ghosh, K.; Grey, J.K. Hierarchical Self-Assembly of Carbon Dots into High-Aspect-Ratio Nanowires. Nano Lett. 2023 , 23 , 9474–9481. [ Google Scholar ] [ CrossRef ]
  • Chen, T.-H.; Tseng, W.-L. Self-Assembly of Monodisperse Carbon Dots into High-Brightness Nanoaggregates for Cellular Uptake Imaging and Iron(III) Sensing. Anal. Chem. 2017 , 89 , 11348–11356. [ Google Scholar ] [ CrossRef ]
  • Liu, L.; Han, J.; Xu, L.; Zhou, J.; Zhao, C.; Ding, S.; Shi, H.; Xiao, M.; Ding, L.; Ma, Z.; et al. Aligned, High-Density Semiconducting Carbon Nanotube Arrays for High-Performance Electronics. Science 2020 , 368 , 850–856. [ Google Scholar ] [ CrossRef ]
  • Joo, Y.; Brady, G.J.; Arnold, M.S.; Gopalan, P. Dose-Controlled, Floating Evaporative Self-Assembly and Alignment of Semiconducting Carbon Nanotubes from Organic Solvents. Langmuir 2014 , 30 , 3460–3466. [ Google Scholar ] [ CrossRef ]
  • Ghamsari, M.; Madrakian, T.; Afkhami, A.; Ahmadi, M. Self-Assembled Graphene-Based Microfibers with Eclectic Optical Properties. Sci. Rep. 2021 , 11 , 5451. [ Google Scholar ] [ CrossRef ]
  • Xu, Y.; Wu, Q.; Sun, Y.; Bai, H.; Shi, G. Three-Dimensional Self-Assembly of Graphene Oxide and DNA into Multifunctional Hydrogels. ACS Nano 2010 , 4 , 7358–7362. [ Google Scholar ] [ CrossRef ] [ PubMed ]
  • Xu, Y.; Sheng, K.; Li, C.; Shi, G. Self-Assembled Graphene Hydrogel via a One-Step Hydrothermal Process. ACS Nano 2010 , 4 , 4324–4330. [ Google Scholar ] [ CrossRef ]
  • Yuan, Z.; Xiao, X.; Li, J.; Zhao, Z.; Yu, D.; Li, Q. Self-Assembled Graphene-Based Architectures and Their Applications. Adv. Sci. 2018 , 5 , 1700626. [ Google Scholar ] [ CrossRef ]
  • Wang, J.; Shi, Z.; Fan, J.; Ge, Y.; Yin, J.; Hu, G. Self-Assembly of Graphene into Three-Dimensional Structures Promoted by Natural Phenolic Acids. J. Mater. Chem. 2012 , 22 , 22459. [ Google Scholar ] [ CrossRef ]
  • Mao, J.; Ge, M.; Huang, J.; Lai, Y.; Lin, C.; Zhang, K.; Meng, K.; Tang, Y. Constructing Multifunctional MOF@rGO Hydro-/Aerogels by the Self-Assembly Process for Customized Water Remediation. J. Mater. Chem. A 2017 , 5 , 11873–11881. [ Google Scholar ] [ CrossRef ]
The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

Bandaru, S.; Arora, D.; Ganesh, K.M.; Umrao, S.; Thomas, S.; Bhaskar, S.; Chakrabortty, S. Recent Advances in Research from Nanoparticle to Nano-Assembly: A Review. Nanomaterials 2024 , 14 , 1387. https://doi.org/10.3390/nano14171387

Bandaru S, Arora D, Ganesh KM, Umrao S, Thomas S, Bhaskar S, Chakrabortty S. Recent Advances in Research from Nanoparticle to Nano-Assembly: A Review. Nanomaterials . 2024; 14(17):1387. https://doi.org/10.3390/nano14171387

Bandaru, Shamili, Deepshika Arora, Kalathur Mohan Ganesh, Saurabh Umrao, Sabu Thomas, Seemesh Bhaskar, and Sabyasachi Chakrabortty. 2024. "Recent Advances in Research from Nanoparticle to Nano-Assembly: A Review" Nanomaterials 14, no. 17: 1387. https://doi.org/10.3390/nano14171387

Article Metrics

Article access statistics, further information, mdpi initiatives, follow mdpi.

MDPI

Subscribe to receive issue release notifications and newsletters from MDPI journals

A review on the green synthesis of nanoparticles, their biological applications, and photocatalytic efficiency against environmental toxins

  • Review Article
  • Published: 12 May 2023
  • Volume 30 , pages 69796–69823, ( 2023 )

Cite this article

nanoparticle review nature

  • Azad Qayoom Malik   ORCID: orcid.org/0000-0003-4858-4351 1 ,
  • Tahir ul Gani Mir 2 ,
  • Deepak Kumar 1 ,
  • Irtiqa Ashraf Mir 1 ,
  • Adfar Rashid 1 ,
  • Mehnaz Ayoub 1 &
  • Saurabh Shukla 2  

1885 Accesses

25 Citations

Explore all metrics

Green synthesis of nanoparticles (NPs) using plant materials and microorganisms has evolved as a sustainable alternative to conventional techniques that rely on toxic chemicals. Recently, green-synthesized eco-friendly NPs have attracted interest for their potential use in various biological applications. Several studies have demonstrated that green-synthesized NPs are beneficial in multiple medicinal applications, including cancer treatment, targeted drug delivery, and wound healing. Additionally, due to their photodegradation activity, green-synthesized NPs are a promising tool in environmental remediation. Photodegradation is a process that uses light and a photocatalyst to turn a pollutant into a harmless product. Green NPs have been found efficient in degrading pollutants such as dyes, herbicides, and heavy metals. The use of microbes and flora in green synthesis technology for nanoparticle synthesis is biologically safe, cost-effective, and eco-friendly. Plants and microbes can now use and accumulate inorganic metallic ions in the environment. Various NPs have been synthesized via the bio-reduction of biological entities or their extracts. There are several biological and environmental uses for biologically synthesized metallic NPs, such as photocatalysis, adsorption, and water purification. Since the last decade, the green synthesis of NPs has gained significant interest in the scientific community. Therefore, there is a need for a review that serves as a one-stop resource that points to relevant and recent studies on the green synthesis of NPs and their biological and photocatalytic efficiency. This review focuses on the green fabrication of NPs utilizing diverse biological systems and their applications in biological and photodegradation processes.

Graphical Abstract

nanoparticle review nature

This is a preview of subscription content, log in via an institution to check access.

Access this article

Subscribe and save.

  • Get 10 units per month
  • Download Article/Chapter or eBook
  • 1 Unit = 1 Article or 1 Chapter
  • Cancel anytime

Price includes VAT (Russian Federation)

Instant access to the full article PDF.

Rent this article via DeepDyve

Institutional subscriptions

nanoparticle review nature

Similar content being viewed by others

nanoparticle review nature

Green Synthesis of Nanoparticles and Their Application for Sustainable Environment

nanoparticle review nature

Green Synthesis of Metal Oxide Nanomaterials and Photocatalytic Degradation of Toxic Dyes

nanoparticle review nature

Explore related subjects

  • Environmental Chemistry

Data availability

Not applicable.

Adeyemi JO, Oriola AO, Onwudiwe DC, Oyedeji AO (2022) Plant extracts mediated metal-based nanoparticles: synthesis and biological applications. Biomolecules 12(5):627. https://doi.org/10.3390/biom12050627

Article   CAS   Google Scholar  

Adibkia K, Alaei-Beirami M, Barzegar-Jalali M, Mohammadi G, Ardestani MS (2012) Evaluation and optimization of factors affecting novel diclofenac sodium-eudragit RS100 nanoparticles. Afr J Pharm Pharmacol 6(12), 941–947. https://www.cabdirect.org/globalhealth/abstract/20123155403

Ahmad N (2012) Green synthesis of silver nanoparticles using extracts of Ananas comosus. Green Sustain Chem 02:141–147. https://doi.org/10.4236/gsc.2012.24020

Ahmed A-A, Hamzah H, Maaroof M, Suood A (2018) Analyzing formation of silver nanoparticles from the filamentous fungus Fusarium oxysporum and their antimicrobial activity. Turk J Biol 42. https://doi.org/10.3906/biy-1710-2

Aj H, Yj K (2011) “Nanoantibiotics”: a new paradigm for treating infectious diseases using nanomaterials in the antibiotics resistant era. J Control Release : Official Journal of the Controlled Release Society 156(2). https://doi.org/10.1016/j.jconrel.2011.07.002

Alam T, Khan R, Ali A, Sher H, Ullah Z, Ali M (2019) Biogenic synthesis of iron oxide nanoparticles via Skimmia laureola and their antibacterial efficacy against bacterial wilt pathogen Ralstonia solanacearum. Mater Sci Eng, C 98:101–108. https://doi.org/10.1016/j.msec.2018.12.117

Alavi M, Karimi N (2018) Characterization, antibacterial, total antioxidant, scavenging, reducing power and ion chelating activities of green synthesized silver, copper and titanium dioxide nanoparticles using Artemisia haussknechtii leaf extract. Artif Cells, Nanomed Biotechnol 46(8):2066–2081. https://doi.org/10.1080/21691401.2017.1408121

Al-Hakkani MF (2020) Biogenic copper nanoparticles and their applications: a review. SN Appl Sci 2(3):505. https://doi.org/10.1007/s42452-020-2279-1

Ali MA, Ahmed T, Wu W, Hossain A, Hafeez R, Islam Masum MM, Wang Y, An Q, Sun G, Li B (2020) Advancements in plant and microbe-based synthesis of metallic nanoparticles and their antimicrobial activity against plant pathogens. Nanomaterials, 10(6), Article 6. https://doi.org/10.3390/nano10061146

Armendariz V, Herrera I, Peralta-Videa JR, Jose-Yacaman M, Troiani H, Santiago P, Gardea-Torresdey JL (2004) Size controlled gold nanoparticle formation by Avena sativa biomass: Use of plants in nanobiotechnology. J Nanopart Res 6(4):377–382. https://doi.org/10.1007/s11051-004-0741-4

Asimuddin M, Shaik MR, Adil SF, Siddiqui MRH, Alwarthan A, Jamil K, Khan M (2020) Azadirachta indica based biosynthesis of silver nanoparticles and evaluation of their antibacterial and cytotoxic effects. J King Saud Univ - Sci 32(1):648–656. https://doi.org/10.1016/j.jksus.2018.09.014

Article   Google Scholar  

Ayala V, Herrera AP, Latorre-Esteves M, Torres-Lugo M, Rinaldi C (2013) Effect of surface charge on the colloidal stability and in vitro uptake of carboxymethyl dextran-coated iron oxide nanoparticles. J Nanopart Res 15(8):1874

Baco-Carles V, Datas L, Tailhades P (2011) Copper nanoparticles prepared from oxalic precursors. ISRN Nanotechnol 2011:1–7. https://doi.org/10.5402/2011/729594

Badawy AME, Luxton TP, Silva RG, Scheckel KG, Suidan MT, Tolaymat TM (2010) Impact of environmental conditions (pH, ionic strength, and electrolyte type) on the surface charge and aggregation of silver nanoparticles suspensions. Environ Sci Technol 44(4):1260–1266

Baer D (2011) Surface characterization of nanoparticles: critical needs and significant challenges. J Surf Anal (online) 17:163–169

Baker S, Rakshith D, Kavitha KS, Santosh P, Kavitha HU, Rao Y, Satish S (2013) Plants: emerging as nanofactories towards facile route in synthesis of nanoparticles. Bioimpacts 3(3):111–117. https://doi.org/10.5681/bi.2013.012

Banu AN, Balasubramanian C (2014) Optimization and synthesis of silver nanoparticles using Isaria fumosorosea against human vector mosquitoes. Parasitol Res 113(10):3843–3851. https://doi.org/10.1007/s00436-014-4052-0

Bar H, Bhui D, Sahoo G, Sarkar P, Pyne S, Misra A (2009) Green synthesis of silver nanoparticles using seed extract of Jatropha curcas. Colloids SurfA: Physicochem Eng Aspects 348:212–216. https://doi.org/10.1016/j.colsurfa.2009.07.021

Barzinjy AA, Azeez HH (2020) Green synthesis and characterization of zinc oxide nanoparticles using Eucalyptus globulus Labill. Leaf extract and zinc nitrate hexahydrate salt. SN Appl Sci 2(5):991. https://doi.org/10.1007/s42452-020-2813-1

Basak S, Venkatram R, Singhal RS (2022) Recent advances in the application of molecularly imprinted polymers (MIPs) in food analysis. Food Control 139:109074. https://doi.org/10.1016/j.foodcont.2022.109074

Bhardwaj K, Dhanjal DS, Sharma A, Nepovimova E, Kalia A, Thakur S, Bhardwaj S, Chopra C, Singh R, Verma R, Kumar D, Bhardwaj P, Kuča K (2020) Conifer-derived metallic nanoparticles: green synthesis and biological applications. Int J Mol Sci 21(23), Article 23. https://doi.org/10.3390/ijms21239028

Bhattarai B, Zaker Y, Bigioni TP (2018) Green synthesis of gold and silver nanoparticles: challenges and opportunities. Curr Opin Green Sustain Chem 12:91–100

Bhosale MG, Sutar RS, Londhe SS, Patil MK (2022) Sol–gel method synthesized Ce-doped TiO2 visible light photocatalyst for degradation of organic pollutants. Appl Organomet Chem 36(4):e6586. https://doi.org/10.1002/aoc.6586

Bhuiyan MdSH, Miah MY, Paul SC, Aka TD, Saha O, Rahaman MdM, Sharif MdJI, Habiba O, Ashaduzzaman Md (2020) Green synthesis of iron oxide nanoparticle using Carica papaya leaf extract: application for photocatalytic degradation of remazol yellow RR dye and antibacterial activity. Heliyon 6(8):e04603. https://doi.org/10.1016/j.heliyon.2020.e04603

Bibi I, Kamal S, Ahmed A, Iqbal M, Nouren S, Jilani K, Nazar N, Amir M, Abbas A, Ata S, Majid F (2017a) Nickel nanoparticle synthesis using Camellia Sinensis as reducing and capping agent: growth mechanism and photo-catalytic activity evaluation. Int J Biol Macromol 103:783–790. https://doi.org/10.1016/j.ijbiomac.2017.05.023

Bibi I, Nazar N, Iqbal M, Kamal S, Nawaz H, Nouren S, Safa Y, Jilani K, Sultan M, Ata S, Rehman F, Abbas M (2017b) Green and eco-friendly synthesis of cobalt-oxide nanoparticle: characterization and photo-catalytic activity. Adv Powder Technol 28(9):2035–2043. https://doi.org/10.1016/j.apt.2017.05.008

Buzea C, Pacheco II, Robbie K (2007) Nanomaterials and nanoparticles: sources and toxicity. Biointerphases 2(4):MR17-71. https://doi.org/10.1116/1.2815690

Cao Y, Zhou G, Zhou R, Wang C, Chi B, Wang Y, Hua C, Qiu J, Jin Y, Wu S (2020) Green synthesis of reusable multifunctional γ-Fe2O3/bentonite modified by doped TiO2 hollow spherical nanocomposite for removal of BPA. Sci Total Environ 708:134669. https://doi.org/10.1016/j.scitotenv.2019.134669

Castillo-Henríquez L, Alfaro-Aguilar K, Ugalde-Álvarez J, Vega-Fernández L, Montes de Oca-Vásquez G, Vega-Baudrit JR (2020) Green synthesis of gold and silver nanoparticles from plant extracts and their possible applications as antimicrobial agents in the agricultural area. Nanomaterials 10(9):1763. https://doi.org/10.3390/nano10091763

Castro-Longoria E, Moreno-Velázquez S, Vilchis-Nestor A, Arenas E, Avalos-Borja M (2012) Production of platinum nanoparticles and nanoaggregates using Neurospora crassa. J Microbiol Biotechnol 22:1000–1004. https://doi.org/10.4014/jmb.1110.10085

Chahardoli A, Karimi N, Sadeghi F, Fattahi A (2018) Green approach for synthesis of gold nanoparticles from Nigella arvensis leaf extract and evaluation of their antibacterial, antioxidant, cytotoxicity and catalytic activities. Artif Cells, Nanomed Biotechnol 46(3):579–588. https://doi.org/10.1080/21691401.2017.1332634

Chakraborty S, Basak B, Dutta S, Bhunia B, Dey A (2013) Decolorization and biodegradation of congo red dye by a novel white rot fungus Alternaria alternata CMERI F6. Bioresour Technol 147. https://doi.org/10.1016/j.biortech.2013.08.117

Chandra H, Kumari P, Bontempi E, Yadav S (2020) Medicinal plants: treasure trove for green synthesis of metallic nanoparticles and their biomedical applications. Biocatal Agric Biotechnol 24:101518

Chandran S, Chaudhary M, Pasricha R, Ahmad A, Sastry M (2006) Synthesis of gold nanotriangles and silver nanoparticles using aloe vera plant extract. Biotechnol Prog 22:577–583. https://doi.org/10.1021/bp0501423

Chang W, Liu S, Qileng A, Liu W, Liu Y (2018) In-situ synthesis of monodispersed Au nanoparticles on eggshell membrane by the extract of Lagerstroemia speciosa leaves for the catalytic reduction of 4-nitrophenol. Mater Res Express 6(1):015002. https://doi.org/10.1088/2053-1591/aae2f0

Chang B-Y, Koo B-S, Kim S-Y (2021) Pharmacological activities for Morus alba L., focusing on the immunostimulatory property from the fruit aqueous extract. Foods 10(8):1966. https://doi.org/10.3390/foods10081966

Chaurasia PK, Bharati SL, Yadava S (2022) Nano-reduction of gold and silver ions: a perspective on the fate of microbial laccases as potential biocatalysts in the synthesis of metals (gold and silver) nano-particles. Curr Res Microb Sci 3:100098. https://doi.org/10.1016/j.crmicr.2021.100098

Chen S, Kucernak A (2004) Electrocatalysis under conditions of high mass transport rate: oxygen reduction on single submicrometer-sized Pt particles supported on carbon. J Phys Chem B 108(10):3262–3276

Chidambaram J, Rahuman A, Roopan S, Kirthi V, Venkatesan J, Kim S-K, Iyappan M, Siva C (2013) Biological approach to synthesize TiO2 nanoparticles using Aeromonas hydrophila and its antibacterial activity. Spectrochimica Acta Part A: Molecular and Biomol Spectrosc 107C. https://doi.org/10.1016/j.saa.2012.12.083

Chopra H, Bibi S, Singh I, Hasan MM, Khan MS, Yousafi Q, Baig AA, Rahman MM, Islam F, Emran TB, Cavalu S (2022) Green metallic nanoparticles: biosynthesis to applications. Front Bioeng Biotechnol. https://doi.org/10.3389/fbioe.2022.874742

Danish MSS, Estrella-Pajulas LL, Alemaida IM, Grilli ML, Mikhaylov A, Senjyu T (2022) Green synthesis of silver oxide nanoparticles for photocatalytic environmental remediation and biomedical applications. Metals, 12(5), Article 5. https://doi.org/10.3390/met12050769

Darroudi M, Ahmad M, Zamiri R, Khorsand Zak A, Abdullah A, Ibrahim N (2011) Time-dependent effect in green synthesis of silver nanoparticles. Int J Nanomed 6. https://doi.org/10.2147/IJN.S17669

Das RK, Gogoi N, Bora U (2011) Green synthesis of gold nanoparticles using Nyctanthes arbortristis flower extract. Bioprocess Biosyst Eng 34(5):615–619. https://doi.org/10.1007/s00449-010-0510-y

Das C, Sen S, Singh T, Ghosh T, Paul SS, Kim TW, Jeon S, Maiti DK, Im J, Biswas G (2020) Green synthesis, characterization and application of natural product coated magnetite nanoparticles for wastewater treatment. Nanomaterials, 10(8), Article 8. https://doi.org/10.3390/nano10081615

Dash SR, Kundu CN (2020) Promising opportunities and potential risk of nanoparticle on the society. IET Nanobiotechnol 14(4):253–260. https://doi.org/10.1049/iet-nbt.2019.0303

de Vinicius Oliveira Brisola Maciel M, da Rosa Almeida A, Machado MH, Elias WC, Gonçalves da Rosa C, Teixeira GL, Noronha CM, Bertoldi FC, Nunes MR, Dutra de Armas R, Manique Barreto PL (2020) Green synthesis, characteristics and antimicrobial activity of silver nanoparticles mediated by essential oils as reducing agents. Biocatal Agric Biotechnol 28:101746. https://doi.org/10.1016/j.bcab.2020.101746

Dikshit PK, Kumar J, Das A, Sadhu S, Sharma S, Singh S, Gupta P, Kim BS (2021) Green synthesis of metallic nanoparticles: applications and limitations. Catalysts 11:1–37. https://doi.org/10.3390/catal11080902

Dil EA, Ghaedi M, Asfaram A (2017) The performance of nanorods material as adsorbent for removal of azo dyes and heavy metal ions: application of ultrasound wave, optimization and modeling. Ultrason Sonochem 34:792–802. https://doi.org/10.1016/j.ultsonch.2016.07.015

Drummer S, Madzimbamuto T, Chowdhury M (2021) Green synthesis of transition-metal nanoparticles and their oxides: a review. Materials, 14(11), Article 11. https://doi.org/10.3390/ma14112700

Dzimitrowicz A, Berent S, Motyka A, Jamroz P, Kurcbach K, Sledz W, Pohl P (2019) Comparison of the characteristics of gold nanoparticles synthesized using aqueous plant extracts and natural plant essential oils of Eucalyptus globulus and Rosmarinus officinalis. Arab J Chem 12(8):4795–4805. https://doi.org/10.1016/j.arabjc.2016.09.007

Edison TJI, Sethuraman MG (2012) Instant green synthesis of silver nanoparticles using Terminalia chebula fruit extract and evaluation of their catalytic activity on reduction of methylene blue. Process Biochem 47(9):1351–1357. https://doi.org/10.1016/j.procbio.2012.04.025

Elamawi RM, Al-Harbi RE, Hendi AA (2018) Biosynthesis and characterization of silver nanoparticles using Trichoderma longibrachiatum and their effect on phytopathogenic fungi. Egyptian J Biol Pest Control 28(1):28. https://doi.org/10.1186/s41938-018-0028-1

Elbeshehy EKF, Elazzazy AM, Aggelis G (2015) Silver nanoparticles synthesis mediated by new isolates of Bacillus spp., nanoparticle characterization and their activity against Bean Yellow Mosaic Virus and human pathogens. Front Microbiol 6:453. https://doi.org/10.3389/fmicb.2015.00453

Eldomany E, Essam TM, Ahmed AE, Farghali A (2018) Biosynthesis physico-chemical optimization of gold nanoparticles as anti-cancer and synergetic antimicrobial activity using Pleurotus ostreatus fungus. J Appl Pharm Sci 8:119–128. https://doi.org/10.7324/JAPS.2018.8516

El-Sayed MEA (2020) Nanoadsorbents for water and wastewater remediation. Sci Total Environ 739:139903. https://doi.org/10.1016/j.scitotenv.2020.139903

Fouda A, El-Din Hassan S, Salem SS, Shaheen TI (2018) In-vitro cytotoxicity, antibacterial, and UV protection properties of the biosynthesized zinc oxide nanoparticles for medical textile applications. Microb Pathog 125:252–261. https://doi.org/10.1016/j.micpath.2018.09.030

Fujiwara M, Imura T (2015) Photo induced membrane separation for water purification and desalination using azobenzene modified anodized alumina membranes. ACS Nano 9(6):5705–5712. https://doi.org/10.1021/nn505970n

Gahlawat G, Roy Choudhury A (2019) A review on the biosynthesis of metal and metal salt nanoparticles by microbes. RSC Adv 9(23):12944–12967. https://doi.org/10.1039/C8RA10483B

Gao G, Ze Y, Li B, Zhao X, Zhang T, Sheng L, Hu R, Gui S, Sang X, Sun Q, Cheng J, Cheng Z, Wang L, Tang M, Hong F (2012) Ovarian dysfunction and gene-expressed characteristics of female mice caused by long-term exposure to titanium dioxide nanoparticles. J Hazard Mater 243:19–27. https://doi.org/10.1016/j.jhazmat.2012.08.049

Ghosh S, Ahmad R, Zeyaullah Md, Khare SK (2021) Microbial nano-factories: synthesis and biomedical applications. Front Chem 9:626834. https://doi.org/10.3389/fchem.2021.626834

Ghotekar S, Dabhane H, Pansambal S, Oza R, Tambade P, Medhane V (2020) A review on biomimetic synthesis of Ag2O Nanoparticles using plant extract, characterization and its recent applications. Adv J Chem-Sect B, 2(3). https://doi.org/10.22034/ajcb.2020.107810

Gnanasekar S, Murugaraj J, Balakrishnan D, Krishnamoorthy V, Jha PK, Seetharaman PK, Vilwanathan R, Sivaperumal S (2017) Antibacterial and cytotoxicity effects of biogenic palladium nanoparticles synthesized using fruit extract of Couroupita guianensis Aubl. J Appl Biomed16. https://doi.org/10.1016/j.jab.2017.10.001

Gopalakrishnan K, Chandel M, Gupta V, Kaur K, Patel A, Kaur K, Kishore A, Prabhakar PK, Singh A, Prasad JS (2023) Valorisation of fruit peel bioactive into green synthesized silver nanoparticles to modify cellulose wrapper for shelf-life extension of packaged bread. Food Res Int 164:112321

Govindasamy S, Thirumarimurugan M, Muthukumaran C (2018) Green synthesis of ZnO nanoparticles using Tecoma castanifolia leaf extract: characterization and evaluation of its antioxidant, bactericidal and anticancer activities. Microchem J 145. https://doi.org/10.1016/j.microc.2018.11.022

Guan Z, Ying S, Ofoegbu PC, Clubb P, Rico C, He F, Hong J (2022) Green synthesis of nanoparticles: current developments and limitations. Environ Technol Innov 102336

Guerrini L, Alvarez-Puebla RA, Pazos-Perez N (2018) Surface modifications of nanoparticles for stability in biological fluids. Materials 11(7):1154

Gupta R, Xie H (2018) Nanoparticles in daily life: applications, toxicity and regulations. J Environ Pathol Toxicol Oncol 37. https://doi.org/10.1615/JEnvironPatholToxicolOncol.2018026009

Gupta K, Chundawat TS (2019) Bio-inspired synthesis of platinum nanoparticles from fungus Fusarium oxysporum: its characteristics, potential antimicrobial, antioxidant and photocatalytic activities. Mater Res Express 6(10):1050d6. https://doi.org/10.1088/2053-1591/ab4219

Habibullah G, Viktorova J, Ulbrich P, Ruml T (2022) Effect of the physicochemical changes in the antimicrobial durability of green synthesized silver nanoparticles during their long-term storage. RSC Adv 12(47):30386–30403

Hennebel T, Van Nevel S, Verschuere S, De Corte S, De Gusseme B, Cuvelier C, Fitts J, Lelie D, Boon N, Verstraete W (2011) Palladium nanoparticles produced by fermentatively cultivated bacteria as catalyst for diatrizoate removal with biogenic hydrogen. Appl Microbiol Biotechnol 91:1435–1445. https://doi.org/10.1007/s00253-011-3329-9

Hernández-Díaz JA, Garza-García JJ, Zamudio-Ojeda A, León-Morales JM, López-Velázquez JC, García-Morales S (2021) Plant-mediated synthesis of nanoparticles and their antimicrobial activity against phytopathogens. J Sci Food Agric 101(4):1270–1287. https://doi.org/10.1002/jsfa.10767

Ho PL, Chow KH, Yuen KY, Ng WS, Chau PY (1998) Comparison of a novel, inhibitor-potentiated disc-diffusion test with other methods for the detection of extended-spectrum beta-lactamases in Escherichia coli and Klebsiella pneumoniae. J Antimicrob Chemother 42(1):49–54. https://doi.org/10.1093/jac/42.1.49

Hosny M, Fawzy M, El-Badry YA, Hussein EE, Eltaweil AS (2022) Plant-assisted synthesis of gold nanoparticles for photocatalytic, anticancer, and antioxidant applications. J Saudi Chem Soc 26(2):101419. https://doi.org/10.1016/j.jscs.2022.101419

Huang J, Li Q, Sun D, Lu Y, Su Y, Yang X, Wang H, Wang Y, Shao W, He N, Hong J, Chen C (2007) Biosynthesis of silver and gold nanoparticles by novel sundried Cinnamomum camphora leaf. Nanotechnology 18(10):105104. https://doi.org/10.1088/0957-4484/18/10/105104

Huang H, Steiniger KA, Lambert TH (2022) Electrophotocatalysis: combining light and electricity to catalyze reactions. J Am Chem Soc 144(28):12567–12583

Ijaz I, Gilani E, Nazir A, Bukhari A (2020) Detail review on chemical, physical and green synthesis, classification, characterizations and applications of nanoparticles. Green Chem Lett Rev 13(3):223–245

Iqtedar M, Aslam M, Farrukh MA, Shahzad A, Abdullah R, Kaleem A (2019) Extracellular biosynthesis, characterization, optimization of silver nanoparticles (AgNPs) using Bacillus mojavensis BTCB15 and its antimicrobial activity against multidrug resistant pathogens. Prep Biochem Biotechnol 49:1–7. https://doi.org/10.1080/10826068.2018.1550654

Iravani S (2011) Green synthesis of metal nanoparticles using plants. Green Chem 13(10):2638–2650

Jafarzadeh S, Jafari SM (2021) Impact of metal nanoparticles on the mechanical, barrier, optical and thermal properties of biodegradable food packaging materials. Crit Rev Food Sci Nutr 61(16):2640–2658

Jalal M, Ansari MA, Alzohairy MA, Ali SG, Khan HM, Almatroudi A, Raees K (2018) Biosynthesis of silver nanoparticles from oropharyngeal Candida glabrata isolates and their antimicrobial activity against clinical strains of bacteria and fungi. Nanomaterials 8(8):586. https://doi.org/10.3390/nano8080586

Javed R, Zia M, Naz S, Aisida SO, Ain N, ul, & Ao, Q. (2020) Role of capping agents in the application of nanoparticles in biomedicine and environmental remediation: recent trends and future prospects. J Nanobiotechnol 18:1–15

Jenning V, Gohla SH (2001) Encapsulation of retinoids in solid lipid nanoparticles (SLN). J Microencapsul 18(2):149–158

Jiang W, Mashayekhi H, Xing B (2009) Bacterial toxicity comparison between nano- and micro-scaled oxide particles. (Environ Pollut Barking, EssexL 1987) 157(5):1619–1625. https://doi.org/10.1016/j.envpol.2008.12.025

Kahsay MH, RamaDevi D, Kumar YP, Mohan BS, Tadesse A, Battu G, Basavaiah K (2018) Synthesis of silver nanoparticles using aqueous extract of Dolichos lablab for reduction of 4-nitrophenol, antimicrobial and anticancer activities. OpenNano 3:28–37. https://doi.org/10.1016/j.onano.2018.04.001

Kalimuthu K, Suresh Babu R, Venkataraman D, Bilal M, Gurunathan S (2008) Biosynthesis of silver nanocrystals by Bacillus licheniformis. Colloids Surf B, Biointerfaces 65(1):150–153. https://doi.org/10.1016/j.colsurfb.2008.02.018

Kamran U, Bhatti HN, Iqbal M, Nazir A (2019) Green synthesis of metal nanoparticles and their applications in different fields: a review. Z Phys Chem 233(9):1325–1349. https://doi.org/10.1515/zpch-2018-1238

Kartha B, Thanikachalam K, Vijayakumar N, Alharbi NS, Kadaikunnan S, Khaled JM, Gopinath K, Govindarajan M (2022) Synthesis and characterization of Ce-doped TiO2 nanoparticles and their enhanced anticancer activity in Y79 retinoblastoma cancer cells. Green Process Synth 11(1):143–149. https://doi.org/10.1515/gps-2022-0011

Katta VKM, Dubey RS (2021) Green synthesis of silver nanoparticles using Tagetes erecta plant and investigation of their structural, optical, chemical and morphological properties. Mater Today: Proceedings 45:794–798. https://doi.org/10.1016/j.matpr.2020.02.809

Koul B, Poonia AK, Yadav D, Jin J-O (2021) Microbe-mediated biosynthesis of nanoparticles: applications and future prospects. Biomolecules 11(6):886. https://doi.org/10.3390/biom11060886

Kumar M, Mehta A, Mishra A, Singh J, Rawat M, Basu S (2018) Biosynthesis of tin oxide nanoparticles using Psidium Guajava leave extract for photocatalytic dye degradation under sunlight. Mater Lett 215:121–124. https://doi.org/10.1016/j.matlet.2017.12.074

Kuppusamy P, Yusoff MM, Maniam GP, Govindan N (2016) Biosynthesis of metallic nanoparticles using plant derivatives and their new avenues in pharmacological applications – an updated report. Saudi Pharm J 24(4):473–484. https://doi.org/10.1016/j.jsps.2014.11.013

Laokul P, Klinkaewnarong J, Phokha S, Seraphin S (2008) Indium oxide (In2O3) nanoparticles using aloe vera plant extract: synthesis and optical properties. Optoelectron Adv Mater Rapid Commun 2

Laouini SE, Bouafia A, Soldatov AV, Algarni H, Tedjani ML, Ali GAM, Barhoum A (2021) Green synthesized of Ag/Ag2O nanoparticles using aqueous leaves extracts of Phoenix dactylifera L. and their azo dye photodegradation. Membranes, 11(7), Article 7. https://doi.org/10.3390/membranes11070468

Levard C, Hotze EM, Lowry GV, Brown GE Jr (2012) Environmental transformations of silver nanoparticles: impact on stability and toxicity. Environ Sci Technol 46(13):6900–6914

Liang T, Qiu X, Ye X, Liu Y, Li Z, Tian B, Yan D (2020) Biosynthesis of selenium nanoparticles and their effect on changes in urinary nanocrystallites in calcium oxalate stone formation. 3 Biotech, 10. https://doi.org/10.1007/s13205-019-1999-7

Liu L, Corma A (2021) Structural transformations of solid electrocatalysts and photocatalysts. Nat Rev Chem 5(4):256–276

López-Miranda JL, Esparza R, Rosas G, Pérez R, Estévez-González M (2019) Catalytic and antibacterial properties of gold nanoparticles synthesized by a green approach for bioremediation applications. 3 Biotech 9(4):135. https://doi.org/10.1007/s13205-019-1666-z

Love AJ, Makarov VV, Sinitsyna OV, Shaw J, Yaminsky IV, Kalinina NO, Taliansky ME (2015) A genetically modified tobacco mosaic virus that can produce gold nanoparticles from a metal salt precursor. Front Plant Sci 6. https://doi.org/10.3389/fpls.2015.00984

Lukman AI, Gong B, Marjo CE, Roessner U, Harris AT (2011) Facile synthesis, stabilization, and anti-bacterial performance of discrete Ag nanoparticles using Medicago sativa seed exudates. J Colloid Interface Sci 353(2):433–444. https://doi.org/10.1016/j.jcis.2010.09.088

Lv Q, Zhang B, Xing X, Zhao Y, Cai R, Wang W, Gu Q (2018) Biosynthesis of copper nanoparticles using Shewanella loihica PV-4 with antibacterial activity: novel approach and mechanisms investigation. J Hazard Mater 347:141–149. https://doi.org/10.1016/j.jhazmat.2017.12.070

Lynch I, Cedervall T, Lundqvist M, Cabaleiro-Lago C, Linse S, Dawson KA (2007) The nanoparticle-protein complex as a biological entity; a complex fluids and surface science challenge for the 21st century. Adv Coll Interface Sci 134–135:167–174. https://doi.org/10.1016/j.cis.2007.04.021

Mahmoudi M, Sant S, Wang B, Laurent S, Sen T (2011) Superparamagnetic iron oxide nanoparticles (SPIONs): development, surface modification and applications in chemotherapy. Adv Drug Deliv Rev 63(1–2):24–46

Malik AQ, Singh H, Kumar A, Aepuru R, Kumar D, Mir ul TG, ul Ain Q, Bhat AA, Mubayi A (2022a) An overview on magnetic separable spinel as a promising materials for photocatalysis and waste water treatment. ES Energy Environ

Malik AQ, Tahir ul Gani M, Amin O, Sathish M, Kumar D (2022b) Synthesis, characterization, photocatalytic effect of CuS-ZnO nanocomposite on photodegradation of Congo Red and phenol pollutant. Inorg Chem Commun 109797

Malik AQ, Lokhande P, Kumar D, Mooney J, Sharma A, Gani Mir TU (2023) Photocatalytic 1 and antimicrobial activity study for cadmium sulphide quantum dots. Mater Res Innov 1–9

Malik AQ, Kumar D (2023) An overview of paclitaxel and molecular imprinted polymers capped with quantum dots as an alternative approach for paclitaxel extraction and detection. Curr Mater Sci: Formerly: Recent Patents on Materials Science 16(2):185–216

CAS   Google Scholar  

Mallikarjunaswamy C, Lakshmi Ranganatha V, Ramu R, Udayabhanu, Nagaraju G (2020) Facile microwave-assisted green synthesis of ZnO nanoparticles: application to photodegradation, antibacterial and antioxidant. J Mater Sci: Mater Electron 31(2):1004–1021. https://doi.org/10.1007/s10854-019-02612-2

Manjunath HulikereJoshi MC (2017) Characterization, antioxidant and antimicrobial activity of silver nanoparticles synthesized using marine endophytic fungus- Cladosporium cladosporioides. Biochem Biophys Rep. https://doi.org/10.1016/j.bbrep.2017.08.011

Masoumbaigi H, Rezaee A, Hosseini H, Hashemi S (2015) Water disinfection by zinc oxide nanoparticle prepared with solution combustion method. Desalin Water Treat 56(9):2376–2381. https://doi.org/10.1080/19443994.2014.961556

Menon S, Devi S, Agarwal H, Kumar V (2019) Efficacy of biogenic selenium nanoparticles from an extract of ginger towards evaluation on anti-microbial and anti-oxidant activities. Colloid Interface Sci Commun 29:1–8. https://doi.org/10.1016/j.colcom.2018.12.004

Mir ul TG, Shukla S, Malik AQ, Singh J, Kumar D (2023) Microwave-assisted synthesis of N-doped carbon quantum dots for detection of methyl orange in saffron. Chem Pap 1–9

Mishra D, Rajurkar S, Mishra N, Jadhav N, Ballurkar B (2017) Green synthesis of gold nanoparticles by Azadirachta indica leaf extract and coating with Morinda citrifolia fruit extract: their characterization. Int J Livest Res 1. https://doi.org/10.5455/ijlr.20170306091736

Mohammadi A, Hashemi M, Hosseini SM (2015) Chitosan nanoparticles loaded with Cinnamomum zeylanicum essential oil enhance the shelf life of cucumber during cold storage. Postharvest Biol Technol 110:203–213

Mohanpuria P, Rana NK, Yadav SK (2008) Biosynthesis of nanoparticles: technological concepts and future applications. J Nanopart Res 10(3):507–517. https://doi.org/10.1007/s11051-007-9275-x

Mohanta YK, Nayak D, Biswas K, Singdevsachan SK, Abd-Allah EF, Hashem A, Alqarawi AA, Yadav D, Mohanta TK (2018) Silver nanoparticles synthesized using wild mushroom show potential antimicrobial activities against food borne pathogens. Molecules : A Journal of Synthetic Chemistry and Natural Product Chemistry 23(3):655. https://doi.org/10.3390/molecules23030655

Mohmed A, Fouda A, Abdel-Rahman M, Hassan S, Gamal S, Salah Salem S, Shaheen Th I (2019). Fungal strain impacts the shape, bioactivity and multifunctional properties of green synthesized zinc oxide nanoparticle. Biocatal Agric Biotechnol 19. https://doi.org/10.1016/j.bcab.2019.101103

Monowar T, Rahman MS, Bhore SJ, Raju G, Sathasivam KV (2018) Silver nanoparticles synthesized by using the endophytic bacterium pantoea ananatis are promising antimicrobial agents against multidrug resistant bacteria. Molecules (basel, Switzerland) 23(12):E3220. https://doi.org/10.3390/molecules23123220

Mukarram M, Khan MM, Corpas F (2021) Silicon nanoparticles elicit an increase in lemongrass (Cymbopogon flexuosus (Steud.) Wats) agronomic parameters with a higher essential oil yield. J Hazard Mater. https://doi.org/10.1016/j.jhazmat.2021.125254

Muñiz Diaz R, Cardoso-Avila PE, Pérez Tavares JA, Patakfalvi R, Villa Cruz V, Ladrón P, de Guevara H, Gutiérrez Coronado O, Arteaga Garibay RI, Saavedra Arroyo QE, Marañón-Ruiz VF, Castañeda Contreras J (2021) Two-step triethylamine-based synthesis of MgO nanoparticles and their antibacterial effect against pathogenic bacteria. Nanomaterials 11(2):410. https://doi.org/10.3390/nano11020410

Muthukumar H, Palanirajan SK, Shanmugam MK, Arivalagan P, Gummadi SN (2022) Photocatalytic degradation of caffeine and E. coli inactivation using silver oxide nanoparticles obtained by a facile green co-reduction method. Clean Technol Environ Policy 24(4):1087–1098. https://doi.org/10.1007/s10098-021-02135-7

Nagajyothi PC, Prabhakar Vattikuti SV, Devarayapalli KC, Yoo K, Shim J, Sreekanth TVM (2020) Green synthesis: photocatalytic degradation of textile dyes using metal and metal oxide nanoparticles-latest trends and advancements. Crit Rev Environ Sci Technol 50(24):2617–2723. https://doi.org/10.1080/10643389.2019.1705103

Nasrollahzadeh M, Sajjadi M, Iravani S, Varma R (2020) Green-synthesized nanocatalysts and nanomaterials for water treatment: current challenges and future perspectives. J Hazard Mater 401:123401. https://doi.org/10.1016/j.jhazmat.2020.123401

Nayantara, Kaur P (2018) Biosynthesis of nanoparticles using eco-friendly factories and their role in plant pathogenicity: a review. Biotechnol Res Innov 2(1):63–73. https://doi.org/10.1016/j.biori.2018.09.003

Ndwandwe BK, Malinga SP, Kayitesi E, Dlamini BC (2021) Advances in green synthesis of selenium nanoparticles and their application in food packaging. Int J Food Sci Technol 56:2640–2650. https://doi.org/10.1111/ijfs.14916

Onitsuka S, Hamada T, Okamura H (2018) Preparation of antimicrobial gold and silver nanoparticles from tea leaf extracts. Colloids Surfaces B: Biointerfaces, 173. https://doi.org/10.1016/j.colsurfb.2018.09.055

Ovais M, Khalil AT, Ayaz M, Ahmad I, Nethi SK, Mukherjee S (2018) Biosynthesis of Metal nanoparticles via microbial enzymes: a mechanistic approach. Int J Mol Sci 19(12):4100. https://doi.org/10.3390/ijms19124100

Pandit C, Roy A, Ghotekar S, Khusro A, Islam MN, Emran TB, Lam SE, Khandaker MU, Bradley DA (2022) Biological agents for synthesis of nanoparticles and their applications. J King Saud Univ-Sci 34(3):101869. https://doi.org/10.1016/j.jksus.2022.101869

Pantidos N, Horsfall L (2014) Biological synthesis of metallic nanoparticles by bacteria, fungi and plants. J Nanomed Nanotechnol 5. https://doi.org/10.4172/2157-7439.1000233

Parmar M, Sanyal M (2022) Extensive study on plant mediated green synthesis of metal nanoparticles and their application for degradation of cationic and anionic dyes. Environ Nanotechnol Monit Manag 17:100624. https://doi.org/10.1016/j.enmm.2021.100624

Parveen K, Banse V, Ledwani L (2016) Green synthesis of nanoparticles: their advantages and disadvantages. 1724(1):020048

Patra JK, Baek K-H (2015) Green nanobiotechnology: factors affecting synthesis and characterization techniques. J Nanomater 2014(219):219. https://doi.org/10.1155/2014/417305

Petla RK, Vivekanandhan S, Misra M, Mohanty A, Satyanarayana N (2012) Soybean (glycine max) leaf extract based green synthesis of palladium nanoparticles. J Biomater Nanobiotechnol 03. https://doi.org/10.4236/jbnb.2012.31003

Phan HT, Haes AJ (2019) What does nanoparticle stability mean? J Phys Chem C 123(27):16495–16507

Pollmann K, Raff J, Merroun M, Fahmy K, Selenska-Pobell S (2006) Metal binding by bacteria from uranium mining waste piles and its technological applications. Biotechnol Adv 24(1):58–68. https://doi.org/10.1016/j.biotechadv.2005.06.002

Prabhu P, Jose V, Lee J (2020) Heterostructured catalysts for electrocatalytic and photocatalytic carbon dioxide reduction. Adv Func Mater 30(24):1910768

Prabhu DM, Cheng J, Chen W, Sunkara A, Mane S, RamKumar DasM, Hozzein W, Duan Y-Q, Li W-J (2016) Sunlight mediated synthesis of silver nanoparticles by a novel actinobacterium (Sinomonas mesophila MPKL 26) and its antimicrobial activity against multi drug resistant Staphylococcus aureus. J Photochem Photobiol B Biol

Pugazhenthiran N, Anandan S, Kathiravan G, Udaya Prakash NK, Crawford S, Ashokkumar M (2009) Microbial synthesis of silver nanoparticles by Bacillus sp. J Nanopart Res 11(7):1811. https://doi.org/10.1007/s11051-009-9621-2

Pulit-Prociak J, Banach M (2016) Silver nanoparticles – a material of the future…? Open Chem 14(1):76–91. https://doi.org/10.1515/chem-2016-0005

Qureshi A, Blaisi NI, Abbas AAO, Khan NA, Rehman S (2021) Prospectus and development of microbes mediated synthesis of nanoparticles. In Ansari MA, Rehman S (Eds.), Microbial Nanotechnology: Green Synthesis and Applications. Springer, pp. 1–15, https://doi.org/10.1007/978-981-16-1923-6_1

Rai R, JamunaBai A (2011) Nanoparticles and their potential application as antimicrobials. Undefined. https://www.semanticscholar.org/paper/Nanoparticles-and-their-potential-application-as-Rai-JamunaBai/386a4fd085f3d53f8cdd53a4f75a4d276aaa4960

Rajabairavi N, Chellappan SR, Raju C, Karthikeyan K, Varutharaju S, Nethaji A, Hameed H, Hameed A, Shajahan, Rajabairavi N, Raju C, Karthikeyan C, Hameed Á, Varutharaju K, Shajahan A, Nethaji S (2017) Biosynthesis of novel zinc oxide nanoparticles (ZnO NPs) using endophytic bacteria Sphingobacterium thalpophilum, pp. 245–254. https://doi.org/10.1007/978-3-319-44890-9_23

Ramteke C, Chakrabarti T, Sarangi BK, Pandey R-A (2012) Synthesis of silver nanoparticles from the aqueous extract of leaves of Ocimum sanctum for enhanced antibacterial activity. J Chem 2013:e278925. https://doi.org/10.1155/2013/278925

Rasheed P, Haq S, Waseem M, Rehman S, Rehman W, Bibi N, Shah SA (2020) Green synthesis of vanadium oxide-zirconium oxide nanocomposite for the degradation of methyl orange and picloram. Mater Res Express 7. https://doi.org/10.1088/2053-1591/ab6fa2

Rashmi BN, Harlapur SF, Avinash B, Ravikumar CR, Nagaswarupa HP, Anil Kumar MR, Gurushantha K, Santosh MS (2020) Facile green synthesis of silver oxide nanoparticles and their electrochemical, photocatalytic and biological studies. Inorg Chem Commun 111:107580. https://doi.org/10.1016/j.inoche.2019.107580

Razavi R, Molaei R, Moradi M, Tajik H, Ezati P, Shafipour Yordshahi A (2020) Biosynthesis of metallic nanoparticles using mulberry fruit (Morus alba L.) extract for the preparation of antimicrobial nanocellulose film. Appl Nanosc. https://doi.org/10.1007/s13204-019-01137-8

Reischauer S, Pieber B (2021) Emerging concepts in photocatalytic organic synthesis. Iscience 24(3):102209

Restrepo CV, Villa CC (2021) Synthesis of silver nanoparticles, influence of capping agents, and dependence on size and shape: a review. Environ Nanotechnol Monit Manag 15:100428

Rice C, Ha S, Masel RI, Waszczuk P, Wieckowski A, Barnard T (2002) Direct formic acid fuel cells. J Power Sources 111(1):83–89. https://doi.org/10.1016/S0378-7753(02)00271-9

Roopan S, Annadurai B, Rajendran K, Khanna G, Arunachalam P (2012) Acaricidal, insecticidal and Larvicidal efficacy of aqueous extract of Annona squamosa peel as biomaterial for the reduction of palladium salts into nanoparticles. Colloids Surf, B 92:209–212. https://doi.org/10.1016/j.colsurfb.2011.11.044

Roy A, Elzaki A, Tirth V, Kajoak S, Osman H, Algahtani A, Islam S, Faizo NL, Khandaker MU, Islam MN, Emran TB, Bilal M (2021) Biological synthesis of nanocatalysts and their applications. Catalysts 11(12), Article 12. https://doi.org/10.3390/catal11121494

Sadegh H, Ali GAM, Gupta VK, Makhlouf ASH, Shahryari-Ghoshekandi R, Nadagouda MN, Sillanpää M, Megiel E (2017) The role of nanomaterials as effective adsorbents and their applications in wastewater treatment. J Nanostruct Chem 7(1), Article 1. https://cyberleninka.org/article/n/1479098

Safaepour M, Shahverdi AR, Shahverdi H, Khorramizadeh MR, Gohari A (2009) Green synthesis of small silver nanoparticles using geraniol and its cytotoxicity against fibrosarcoma-Wehi 164. Avicenna J Med Biotechnol 1:111–115

Salem TA, Fetian NA, Elsheery NI (2019) Nanotechnology for Polluted soil remediation. In Panpatte DG, Jhala YK (Eds.), Nanotechnology for Agriculture: Advances for Sustainable Agriculture. Springer, pp. 285–305, https://doi.org/10.1007/978-981-32-9370-0_15

Salem SS, Fouda A (2021) Green synthesis of metallic nanoparticles and their prospective biotechnological applications: an overview. Biol Trace Elem Res 199:344–370

Salimi M, Rassi Y, Chatrabgoun O, Kamali A, Oshaghi MA, Shiri-Ghaleh V, Moradi M, Rafizadeh S, Akbarzadeh K, Parkhideh SZ (2018) Toxicological analysis of insects on the corpse: a valuable source of information in forensic investigations. J Arthropod-Borne Dis 12(3):219–231. https://doi.org/10.18502/jad.v12i3.74 . (Scopus)

Sangaru SS, Rai A, Ahmad A, Sastry M (2004) Biosynthesis of silver and gold nanoparticles from extracts of different parts of the geranium plant. Appl Nanosci 1:69–77

Google Scholar  

Santhosh C, Velmurugan V, Jacob G, Jeong SK, Grace AN, Bhatnagar A (2016) Role of nanomaterials in water treatment applications: a review. Chem Eng J 306:1116–1137. https://doi.org/10.1016/j.cej.2016.08.053

Saratale RG, Saratale GD, Shin HS, Jacob JM, Pugazhendhi A, Bhaisare M, Kumar G (2018) New insights on the green synthesis of metallic nanoparticles using plant and waste biomaterials: current knowledge, their agricultural and environmental applications. Environ Sci Pollut Res 25:10164–10183

Sarathy V, Tratnyek PG, Nurmi JT, Baer DR, Amonette JE, Chun CL, Penn RL, Reardon EJ (2008) Aging of iron nanoparticles in aqueous solution: effects on structure and reactivity. J Phys Chem C 112(7):2286–2293. https://doi.org/10.1021/jp0777418

Saravanakumar K, Hu X, Chelliah R, Oh D-H, Kathiresan K, Wang M-H (2020) Biogenic silver nanoparticles-polyvinylpyrrolidone based glycerosomes coating to expand the shelf life of fresh-cut bell pepper (Capsicum annuum L. var. Grossum (L.) Sendt). Postharvest Biol Technol 160:111039

Saravanan M, Barik SK, MubarakAli D, Prakash P, Pugazhendhi A (2018) Synthesis of silver nanoparticles from Bacillus brevis (NCIM 2533) and their antibacterial activity against pathogenic bacteria. Microb Pathog 116:221–226. https://doi.org/10.1016/j.micpath.2018.01.038

Schlüter M, Hentzel T, Suarez C, Koch M, Lorenz W, Böhm L, Duering R-A, Koinig K, Bunge M (2014) Synthesis of novel palladium(0) nanocatalysts by microorganisms from heavy-metal-influenced high-alpine sites for dehalogenation of polychlorinated dioxins. Chemosphere 117C:462–470. https://doi.org/10.1016/j.chemosphere.2014.07.030

Schubert J, Chanana M (2019) Coating matters: Review on colloidal stability of nanoparticles with biocompatible coatings in biological media, living cells and organisms. Curr Med Chem 25(35):4556

Seifunnisha O, Jayaraj S (2020) Aloe vera mediated green synthesis of ZnO nanostructure under sol-gel method: effect of antimicrobial activity. J Nano-Electron Phys 12:02041–1. https://doi.org/10.21272/jnep.12(2).02041

Seil JT, Webster TJ (2012) Antimicrobial applications of nanotechnology: methods and literature. Int J Nanomed 7:2767–2781. https://doi.org/10.2147/IJN.S24805

Shahzad A, Iqtedar M, Saeed H, Hussain SZ, Chaudhary A, Abdullah R, Kaleem A (2019) Mycosynthesis of size-controlled silver nanoparticles through optimization of process variables by response surface methodology. Polish J Microbiol 68(1):35–42. https://doi.org/10.21307/pjm-2019-004

Shamprasad BR, Lotha R, Nagarajan S, Sivasubramanian A (2022) Metal nanoparticles functionalized with nutraceutical Kaempferitrin from edible Crotalaria juncea, exert potent antimicrobial and antibiofilm effects against Methicillin-resistant Staphylococcus aureus. Sci Rep 12. https://doi.org/10.1038/s41598-022-11004-2

Shehab MM, Elbialy ZI, Tayel AA, Moussa SH, Al-Hawary II (2022) Quality boost and shelf-life prolongation of african catfish fillet using Lepidium sativum mucilage extract and selenium nanoparticles. J Food Qual 2022

Shipley HJ, Engates KE, Guettner AM (2011) Study of iron oxide nanoparticles in soil for remediation of arsenic. J Nanopart Res 13(6):2387–2397. https://doi.org/10.1007/s11051-010-9999-x

Shubha JP, Kavalli K, Adil SF, Assal ME, Hatshan MR, Dubasi N (2022) Facile green synthesis of semiconductive ZnO nanoparticles for photocatalytic degradation of dyes from the textile industry: a kinetic approach. J King Saud Univ-Sci 34(5):102047. https://doi.org/10.1016/j.jksus.2022.102047

Singh M, Kalaivani R, Manikandan S, Sangeetha N, Kumaraguru AK (2013) Facile green synthesis of variable metallic gold nanoparticle using Padina gymnospora, a brown marine macroalga. Appl Nanosci 3(2):145–151. https://doi.org/10.1007/s13204-012-0115-7

Singh K, Panghal M, Kadyan S, Chaudhary U, Yadav JP (2014) Green silver nanoparticles of Phyllanthus amarus: as an antibacterial agent against multi drug resistant clinical isolates of Pseudomonas aeruginosa. J Nanobiotechnol 12:40. https://doi.org/10.1186/s12951-014-0040-x

Singh J, Dutta T, Kim K-H, Rawat M, Samddar P, Kumar P (2018) ‘Green’ synthesis of metals and their oxide nanoparticles: applications for environmental remediation. J Nanobiotechnol 16(1):84. https://doi.org/10.1186/s12951-018-0408-4

Sintubin L, De Windt W, Dick J, Mast J, van der Ha D, Verstraete W, Boon N (2009) Lactic acid bacteria as reducing and capping agent for the fast and efficient production of silver nanoparticles. Appl Microbiol Biotechnol 84(4):741–749. https://doi.org/10.1007/s00253-009-2032-6

Siripireddy B, Mandal BK (2017) Facile green synthesis of zinc oxide nanoparticles by Eucalyptus globulus and their photocatalytic and antioxidant activity. Adv Powder Technol 28(3):785–797. https://doi.org/10.1016/j.apt.2016.11.026

Song Y, Chen L (2015) Effect of net surface charge on physical properties of the cellulose nanoparticles and their efficacy for oral protein delivery. Carbohyd Polym 121:10–17. https://doi.org/10.1016/j.carbpol.2014.12.019

Soto-Robles CA, Luque PA, Gómez-Gutiérrez CM, Nava O, Vilchis-Nestor AR, Lugo-Medina E, Ranjithkumar R, Castro-Beltrán A (2019) Study on the effect of the concentration of Hibiscus sabdariffa extract on the green synthesis of ZnO nanoparticles. Results Phys 15:102807. https://doi.org/10.1016/j.rinp.2019.102807

Soundarrajan C, Sankari A, Dhandapani P, Maruthamuthu S, Ravichandran S, Sozhan G, Palaniswamy N (2011) Rapid biological synthesis of platinum nanoparticles using Ocimum sanctum for water electrolysis applications. Bioprocess Biosyst Eng 35:827–833. https://doi.org/10.1007/s00449-011-0666-0

Sreekanth TVM, Nagajyothi PC, Muthuraman P, Enkhtaivan G, Vattikuti SVP, Tettey CO, Kim DH, Shim J, Yoo K (2018) Ultra-sonication-assisted silver nanoparticles using Panax ginseng root extract and their anti-cancer and antiviral activities. J Photochem Photobiol, B 188:6–11. https://doi.org/10.1016/j.jphotobiol.2018.08.013

Srinath BS, Namratha K, Byrappa K (2018) Eco-friendly synthesis of gold nanoparticles by Bacillus subtilis and their environmental applications. Adv Sci Lett 24(8):5942–5946. https://doi.org/10.1166/asl.2018.12224

Subba Rao Y, Kotakadi VS, Prasad TNVKV, Reddy AV, Sai Gopal DVR (2013) Green synthesis and spectral characterization of silver nanoparticles from Lakshmi tulasi (Ocimum sanctum) leaf extract. Spectrochim Acta Part A Mol Biomol Spectrosc 103:156–159. https://doi.org/10.1016/j.saa.2012.11.028

Subhapriya S, Gomathipriya P (2018) Green synthesis of titanium dioxide (TiO2) nanoparticles by Trigonella foenum-graecum extract and its antimicrobial properties. Microb Pathog 116:215–220. https://doi.org/10.1016/j.micpath.2018.01.027

Sumi MB, Devadiga A, Vidya Shetty K, Saidutta MB (2017) Solar photocatalytically active, engineered silver nanoparticle synthesis using aqueous extract of mesocarp of Cocos nucifera (Red Spicata Dwarf). J Exp Nanosci 12(1):14–32. https://doi.org/10.1080/17458080.2016.1251622

Suriyaprom S, Kaewkod T, Promputtha I, Desvaux M, Tragoolpua Y (2021) Evaluation of antioxidant and antibacterial activities of white mulberry (Morus alba L.) fruit extracts. Plants 10(12):2736. https://doi.org/10.3390/plants10122736

Suryavanshi P, Pandit R, Gade A, Derita M, Zachino S, Rai M (2017) Colletotrichum sp.- mediated synthesis of sulphur and aluminium oxide nanoparticles and its in vitro activity against selected food-borne pathogens. LWT - Food Sci Technol 81. https://doi.org/10.1016/j.lwt.2017.03.038

Tagad CK, Dugasani SR, Aiyer R, Park S, Kulkarni A, Sabharwal S (2013) Green synthesis of silver nanoparticles and their application for the development of optical fiber based hydrogen peroxide sensor. Sens Actuators, B Chem 183:144–149

Tahir K, Nazir S, Ahmad A, Li B, Khan AU, Khan ZUH, Khan F, Khan Q, Khan A, Rehman A (2016) Facile and green synthesis of phytochemicals capped platinum nanoparticles and in vitro their superior antibacterial activity. J Photochem Photobiol B, Biology 166:246–251. https://doi.org/10.1016/j.jphotobiol.2016.12.016

Tahir M, Sagir M, Abas N (2019) Enhanced photocatalytic performance of CdO-WO3 composite for hydrogen production. Int J Hydrogen Energy. https://doi.org/10.1016/j.ijhydene.2019.07.220

Taran M, Rad M, Alavi M (2018) Biosynthesis of TiO2 and ZnO nanoparticles by Halomonas elongata IBRC-M 10214 in different conditions of medium. BioImpacts: BI 8(2):81–89. https://doi.org/10.15171/bi.2018.10

Thangavelu RM, Ganapathy R, Ramasamy P, Krishnan K (2020) Fabrication of virus metal hybrid nanomaterials: an ideal reference for bio semiconductor. Arab J Chem 13(1):2750–2765. https://doi.org/10.1016/j.arabjc.2018.07.006

Thomas R, Janardhanan A, Varghese RT, Soniya EV, Mathew J, Radhakrishnan EK (2014) Antibacterial properties of silver nanoparticles synthesized by marine Ochrobactrum sp. Braz J Microbiol: [publication of the Brazilian Society for Microbiology] 45(4):1221–1227. https://doi.org/10.1590/s1517-83822014000400012

Tiu BDB, Kernan DL, Tiu SB, Wen AM, Zheng Y, Pokorski JK, Advincula RC, Steinmetz NF (2017) Electrostatic layer-by-layer construction of fibrous TMV biofilms. Nanoscale 9(4):1580–1590. https://doi.org/10.1039/c6nr06266k

Tripathi A, Liu S, Singh PK, Kumar N, Pandey AC, Tripathi DK, Chauhan DK, Sahi S (2017) Differential phytotoxic responses of silver nitrate (AgNO3) and silver nanoparticle (AgNps) in Cucumis sativus L. Plant Gene. https://doi.org/10.1016/j.plgene.2017.07.005

Tungittiplakorn W, Lion LW, Cohen C, Kim J-Y (2004) Engineered polymeric nanoparticles for soil remediation. Environ Sci Technol 38(5):1605–1610. https://doi.org/10.1021/es0348997

ul Gani Mir T, Malik AQ, Singh J, Shukla S, Kumar D (2022) An overview of molecularly imprinted polymers embedded with quantum dots and their implementation as an alternative approach for extraction and detection of Crocin. ChemistrySelect 7(21):e202200829

Valodkar M, Jadeja RN, Thounaojam MC, et al (2011) Biocompatible synthesis of peptide capped copper nanoparticles and their biological effect on tumor cells. Mater Chem Phys 128:83–89. https://doi.org/10.1016/j.matchemphys.2011.02.039

Velayutham K, Rahuman AA, Rajakumar G, Santhoshkumar T, Marimuthu S, Jayaseelan C, Bagavan A, Kirthi AV, Kamaraj C, Zahir AA, Elango G (2012) Evaluation of Catharanthus roseus leaf extract-mediated biosynthesis of titanium dioxide nanoparticles against Hippobosca maculata and Bovicola ovis. Parasitol Res 111(6):2329–2337. https://doi.org/10.1007/s00436-011-2676-x

Waglewska E, Pucek-Kaczmarek A, Bazylińska U (2020) Novel surface-modified bilosomes as functional and biocompatible nanocarriers of hybrid compounds. Nanomaterials 10(12):2472

Wang W, Xu X, Zhou W, Shao Z (2017) Recent progress in metal-organic frameworks for applications in electrocatalytic and photocatalytic water splitting. Adv Sci 4(4):1600371

Wang Y, O’Connor D, Shen Z, Lo IMC, Tsang DCW, Pehkonen S, Pu S, Hou D (2019) Green synthesis of nanoparticles for the remediation of contaminated waters and soils: constituents, synthesizing methods, and influencing factors. J Clean Prod 226:540–549. https://doi.org/10.1016/j.jclepro.2019.04.128

Wang P, Wang F, Jiang H, Zhang Y, Zhao M, Xiong R, Ma J (2020) Strong improvement of nanofiltration performance on micropollutant removal and reduction of membrane fouling by hydrolyzed-aluminum nanoparticles. Water Res 175:115649. https://doi.org/10.1016/j.watres.2020.115649

Wang W-N, Tarafdar J, Biswas P (2013) Nanoparticle synthesis and delivery by an aerosol route for watermelon plant foliar uptake. J Nanopart Res 15. https://doi.org/10.1007/s11051-013-1417-8

Wani AK, Akhtar N, Mir ul TG, Singh R, Jha PK, Mallik SK, Sinha S, Tripathi SK, Jain A, Jha A (2023) Targeting apoptotic pathway of cancer cells with phytochemicals and plant-based nanomaterials. Biomolecules 13(2):194

Wypij M, Czarnecka J, Świecimska M, Dahm H, Rai M, Golinska P (2018) Synthesis, characterization and evaluation of antimicrobial and cytotoxic activities of biogenic silver nanoparticles synthesized from Streptomyces xinghaiensis OF1 strain. World J Microbiol Biotechnol 34(2):23. https://doi.org/10.1007/s11274-017-2406-3

Xiao Q, Jaatinen E, Zhu H (2014) Direct photocatalysis for organic synthesis by using plasmonic-metal nanoparticles irradiated with visible light. Chem–An Asian J 9(11):3046–3064

Xu J, Huang Y, Zhu S, Abbes N, Jing X, Zhang L (2021) A review of the green synthesis of ZnO nanoparticles using plant extracts and their prospects for application in antibacterial textiles. J Eng Fibers Fabr 16:15589250211046242. https://doi.org/10.1177/15589250211046242

Yurekli Y (2016) Removal of heavy metals in wastewater by using zeolite nano-particles impregnated polysulfone membranes. J Hazard Mater 309:53–64. https://doi.org/10.1016/j.jhazmat.2016.01.064

Zhang W, Xiao B, Fang T (2018a) Chemical transformation of silver nanoparticles in aquatic environments: mechanism, morphology and toxicity. Chemosphere 191:324–334

Zhang Y, Dong Y, Zhou J, Li X, Wang F (2018b) Application of plant viruses as a biotemplate for nanomaterial fabrication. Molecules 23(9), Article 9. https://doi.org/10.3390/molecules23092311

Zhang D, Ma X, Gu Y, Huang H, Zhang G (2020) Green Synthesis of metallic nanoparticles and their potential applications to treat cancer. Front Chem 8. https://www.frontiersin.org/articles/10.3389/fchem.2020.00799

Zhao C, Wang B, Theng BKG, Wu P, Liu F, Wang S, Lee X, Chen M, Li L, Zhang X (2021) Formation and mechanisms of nano-metal oxide-biochar composites for pollutants removal: a review. Sci Total Environ 767:145305. https://doi.org/10.1016/j.scitotenv.2021.145305

Download references

Author information

Authors and affiliations.

School of Bioengineering and Biosciences, Lovely Professional University, Phagwara, Punjab, India, 144411

Azad Qayoom Malik, Deepak Kumar, Irtiqa Ashraf Mir, Adfar Rashid & Mehnaz Ayoub

School of Chemical Engineering and Physical Sciences, Lovely Professional University, Phagwara, Punjab, India, 144411

Tahir ul Gani Mir & Saurabh Shukla

You can also search for this author in PubMed   Google Scholar

Contributions

Conceptualization: Azad Qayoom Malik, Tahir ul Gani Mir; data collection: Azad Qayoom Malik, Adfar Rashid, Mehnaz Ayoub, Irtiqa Ashraf Mir; draft manuscript preparation: Tahir ul Gani Mir, Azad Qayoom Malik; review and editing: Deepak Kumar, Saurabh Shukla; supervision/visualization: Deepak Kumar, Saurabh Shukla.

Corresponding author

Correspondence to Azad Qayoom Malik .

Ethics declarations

Ethical approval, consent to participate, consent for publication.

All authors reviewed and approved the final version of the manuscript.

Conflict of interest

The authors declare no competing interests.

Additional information

Responsible Editor: George Z. Kyzas

Publisher's note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Malik, A.Q., Mir, T.u.G., Kumar, D. et al. A review on the green synthesis of nanoparticles, their biological applications, and photocatalytic efficiency against environmental toxins. Environ Sci Pollut Res 30 , 69796–69823 (2023). https://doi.org/10.1007/s11356-023-27437-9

Download citation

Received : 04 March 2023

Accepted : 01 May 2023

Published : 12 May 2023

Issue Date : June 2023

DOI : https://doi.org/10.1007/s11356-023-27437-9

Share this article

Anyone you share the following link with will be able to read this content:

Sorry, a shareable link is not currently available for this article.

Provided by the Springer Nature SharedIt content-sharing initiative

  • Green synthesis
  • Nanoparticless
  • Environment remediation
  • Water treatment
  • Photocatalysis
  • Antimicrobial activity
  • Find a journal
  • Publish with us
  • Track your research

U.S. flag

An official website of the United States government

The .gov means it’s official. Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

The site is secure. The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

  • Publications
  • Account settings

Preview improvements coming to the PMC website in October 2024. Learn More or Try it out now .

  • Advanced Search
  • Journal List
  • J Nanobiotechnology

Logo of nanobio

Nanoparticle classification, physicochemical properties, characterization, and applications: a comprehensive review for biologists

Nadeem joudeh.

Department of Biosciences, University of Oslo, Blindern, P.O. Box 1066, 0316 Oslo, Norway

Associated Data

Not applicable.

Interest in nanomaterials and especially nanoparticles has exploded in the past decades primarily due to their novel or enhanced physical and chemical properties compared to bulk material. These extraordinary properties have created a multitude of innovative applications in the fields of medicine and pharma, electronics, agriculture, chemical catalysis, food industry, and many others. More recently, nanoparticles are also being synthesized ‘biologically’ through the use of plant- or microorganism-mediated processes, as an environmentally friendly alternative to the expensive, energy-intensive, and potentially toxic physical and chemical synthesis methods. This transdisciplinary approach to nanoparticle synthesis requires that biologists and biotechnologists understand and learn to use the complex methodology needed to properly characterize these processes. This review targets a bio-oriented audience and summarizes the physico–chemical properties of nanoparticles, and methods used for their characterization. It highlights why nanomaterials are different compared to micro- or bulk materials. We try to provide a comprehensive overview of the different classes of nanoparticles and their novel or enhanced physicochemical properties including mechanical, thermal, magnetic, electronic, optical, and catalytic properties. A comprehensive list of the common methods and techniques used for the characterization and analysis of these properties is presented together with a large list of examples for biogenic nanoparticles that have been previously synthesized and characterized, including their application in the fields of medicine, electronics, agriculture, and food production. We hope that this makes the many different methods more accessible to the readers, and to help with identifying the proper methodology for any given nanoscience problem.

Nano etymology

The prefix nano is derived from the Greek word nanos, “a dwarf”. In 1947, at the 14th conference of the International Union of Pure and Applied Chemistry (IUPAC), the prefix nano was officially adopted to describe the one-billionth part (10 –9 ) of a unit 1 . In scientific literature, the prefix nano has been adopted as a popular label in many fields of modern science to describe small entities and processes. These terms include, but are not limited to nanoscience, nanotechnology, nanorobots, nanomagnets, nanoelectronics, nanoencapsulation, etc. [ 1 ]. In all of these cases, the prefix nano is used to describe “very small” entities or processes, most often at actual nanometer scale.

Definitions

Nanoscience is a branch of science that comprises the study of properties of matter at the nanoscale, and particularly focuses on the unique, size-dependent properties of solid-state materials [ 2 ]. Nanotechnology is the branch that comprises the synthesis, engineering, and utilization of materials whose size ranges from 1 to 100 nm, known as nanomaterials [ 3 ]. The birth of nanoscience and nanotechnology concepts is usually linked to the famous lecture of Nobel laureate Richard Feynman at the 1959 meeting of the American Physical Society, ‘‘There’s Plenty of Room at the Bottom’’ [ 4 ]. However, the use of nanotechnology and nanomaterials goes back in history long before that.

History of nanotechnology

Long before the era of nanotechnology, people were unknowingly coming across various nanosized objects and using nano-level processes. In ancient Egypt, dyeing hair in black was common and was for a long time believed to be based on plant products such as henna [ 5 ]. However, recent research on hair samples from ancient Egyptian burial sites showed that hair was dyed with paste from lime, lead oxide, and water [ 6 ]. In this dyeing process, galenite (lead sulfide, PbS) nanoparticles are formed. The ancient Egyptians were able to make the dyeing paste react with sulfur (part of hair keratin) and produce small PbS nanoparticles which provided even and steady dyeing.

Probably the most famous example for the ancient use of nanotechnology is the Lycurgus Cup (fourth century CE). This ancient roman cup possesses unusual optical properties; it changes its color based on the location of the light source. In natural light, the cup is green, but when it is illuminated from within (with a candle), it becomes red. The recent analysis of this cup showed that it contains 50–100 nm Au and Ag nanoparticles [ 7 ], which are responsible for the unusual coloring of the cup through the effects of plasmon excitation of electrons [ 8 ]. The ancient use of nanotechnology does not stop here, in fact, there is evidence for the early use of nanotechnology processes in Mesopotamia, Ancient India, and the Maya [ 9 , 10 ].

Why nanomaterials are different

Today, due to their unique properties, nanomaterials are used in a wide range of applications, such as catalysis, water treatment, energy storage, medicine, agriculture, etc . [ 11 – 13 ]. Two main factors cause nanomaterials to behave significantly differently than the same materials at larger dimensions: surface effects and quantum effects [ 14 ]. These factors make nanomaterials exhibit enhanced or novel mechanical, thermal, magnetic, electronic, optical, and catalytic properties [ 1 , 15 , 16 ].

Nanomaterials have different surface effects compared to micromaterials or bulk materials, mainly due to three reasons; (a) dispersed nanomaterials have a very large surface area and high particle number per mass unit, (b) the fraction of atoms at the surface in nanomaterials is increased, and (c) the atoms situated at the surface in nanomaterials have fewer direct neighbors [ 1 , 14 ]. As a consequence of each of these differences, the chemical and physical properties of nanomaterials change compared to their larger-dimension counterparts. For instance, having fewer direct neighbor atoms for the atoms situated at the surface results in lowering the binding energy per atom for nanomaterials. This change directly affects the melting temperature of nanomaterials following the Gibbs–Thomson equation, e.g., the melting point of 2.5 nm gold nanoparticles is 407 degrees lower than the melting point of bulk gold [ 14 ]. Larger surface areas and larger surface-to-volume ratios generally increases the reactivity of nanomaterials due to the larger reaction surface [ 1 ], as well as resulting in significant effects of surface properties on their structure [ 17 ]. The dispersity of nanomaterials is a key factor for the surface effects. The strong attractive interactions between particles can result in the agglomeration and aggregation of nanomaterials, which negatively affects their surface area and their nanoscale properties [ 18 ]. Agglomeration can be prevented by increasing the zeta potential of nanomaterials (increasing the repulsive force) [ 19 ], optimizing the degree of hydrophilicity/hydrophobicity of the nanomaterial, or by optimizing the pH and the ionic strength of the suspension medium [ 20 ].

Nanomaterials display distinct size-dependent properties in the 1–100 nm range where quantum phenomena are involved. When the material radius approaches the asymptotic exciton Bohr radius (the separation distance between the electron and hole), the influence of quantum confinement becomes apparent [ 17 ]. In other words, by shrinking the size of the material, quantum effects become more pronounced, and nanomaterials become quantal. Those quantum structures are physical structures where all the charge carriers (electrons and holes) are confined within the physical dimensions [ 21 ]. As a result of quantum confinement effects, for instance, some non-magnetic materials in bulk such as palladium, platinum, and gold become magnetic in the nanoscale [ 14 ]. Quantum confinement can also result in significant changes in electron affinity or the ability to accept or donate electrical charges, which is directly reflected on the catalytic properties of the material. For example, the catalytic activity of cationic platinum clusters in N 2 O decomposition is dictated by the number of atoms in the cluster. 6–9, 11, 12, 15, and 20 atom-containing clusters are very reactive, while clusters with 10, 13, 14, and 19 atoms have low reactivity [ 14 ].

Classification of nanomaterials

The key elements of nanotechnology are the nanomaterials. Nanomaterials are defined as materials where at least one of their dimensions is in the nanoscale, i.e. smaller than 100 nm [ 22 ]. Based on their dimensionalities, nanomaterials are placed into four different classes, summarized in Fig.  1 .

  • Zero-dimensional nanomaterials (0-D): the nanomaterials in this class have all their three dimensions in the nanoscale range. Examples are quantum dots, fullerenes, and nanoparticles.
  • One-dimensional nanomaterials (1-D): the nanomaterials in this class have one dimension outside the nanoscale. Examples are nanotubes, nanofibers, nanorods, nanowires, and nanohorns.
  • Two-dimensional nanomaterials (2-D): the nanomaterials in this class have two dimensions outside the nanoscale. Examples are nanosheets, nanofilms, and nanolayers.
  • Three-dimensional nanomaterials (3-D) or bulk nanomaterials: in this class the materials are not confined to the nanoscale in any dimension. This class contains bulk powders, dispersions of nanoparticles, arrays of nanowires and nanotubes, etc .

An external file that holds a picture, illustration, etc.
Object name is 12951_2022_1477_Fig1_HTML.jpg

Nanomaterials classification based on dimensionality

Nanoparticles (NPs)

The International Organization for Standardization (ISO) defines nanoparticles as nano-objects with all external dimensions in the nanoscale, where the lengths of the longest and the shortest axes of the nano-object do not differ significantly. If the dimensions differ significantly (typically by more than three times), terms such as nanofibers or nanoplates maybe preferred to the term NPs 2 .

NPs can be of different shapes, sizes, and structures. They can be spherical, cylindrical, conical, tubular, hollow core, spiral, etc., or irregular [ 23 ]. The size of NPs can be anywhere from 1 to 100 nm. If the size of NPs gets lower than 1 nm, the term atom clusters is usually preferred. NPs can be crystalline with single or multi-crystal solids, or amorphous. NPs can be either loose or agglomerated [ 24 ].

NPs can be uniform, or can be composed of several layers. In the latter case, the layers often are: (a) The surface layer, which usually consists of a variety of small molecules, metal ions, surfactants, or polymers. (b) The shell layer, which is made of a chemically different material from the core layer. (c) The core layer, which is the central portion of the NP [ 25 ].

Classification of NPs

Based on their composition, NPs are generally placed into three classes: organic, carbon-based, and inorganic [ 23 ].

Organic NPs

This class comprises NPs that are made of proteins, carbohydrates, lipids, polymers, or any other organic compounds [ 26 ]. The most prominent examples of this class are dendrimers, liposomes, micelles, and protein complexes such as ferritin (shown in Fig.  2 ). These NPs are typically non-toxic, bio-degradable, and can in some cases, e.g., for liposomes, have a hollow core. Organic NPs are sensitive to thermal and electromagnetic radiation such as heat and light [ 23 ]. In addition, they are often formed by non-covalent intermolecular interactions, which makes them more labile in nature and offers a route for clearance from the body [ 27 ]. There are different parameters that determine the potential field of application of organic NPs, e.g., composition, surface morphology, stability, carrying capacity, etc . Today, organic NPs are mostly used in the biomedical field in targeted drug delivery [ 23 ] and cancer therapy [ 28 ].

An external file that holds a picture, illustration, etc.
Object name is 12951_2022_1477_Fig2_HTML.jpg

Types of organic NPs. A Dendrimers; B liposomes; C micelles; and D ferritin

Carbon-based NPs

This class comprises NPs that are made solely from carbon atoms [ 23 ]. Famous examples of this class are fullerenes, carbon black NPs, and carbon quantum dots (shown in Fig.  3 ). Fullerenes are carbon molecules that are characterized by a symmetrical closed-cage structure. C 60 fullerenes consist of 60 carbon atoms arranged in the shape of a soccer ball [ 29 ], but also other types of fullerenes such as C 70 and C 540 fullerenes have been described [ 30 ]. Carbon black NPs are grape-like aggregates of highly fused spherical particles [ 31 ]. Carbon quantum dots consist of discrete, quasi-spherical carbon NPs with sizes below 10 nm [ 32 ]. Carbon-based NPs unite the distinctive properties of sp 2 -hybridized carbon bonds with the unusual physicochemical properties at the nanoscale. Due to their unique electrical conductivity, high strength, electron affinity, optical, thermal, and sorption properties [ 25 , 33 ], carbon-based NPs are used in a wide range of application such as drug delivery [ 34 ], energy storage [ 35 ], bioimaging [ 36 ], photovoltaic devices, and environmental sensing applications to monitor microbial ecology or to detect microbial pathogens [ 33 ]. Nanodiamonds and carbon nano onions are more complex, carbon-based NPs. Due to their characteristic low toxicity and biocompatibility, they are used in drug delivery and tissue engineering applications [ 37 , 38 ].

An external file that holds a picture, illustration, etc.
Object name is 12951_2022_1477_Fig3_HTML.jpg

Different types of carbon-based NPs. A C 60 fullerene; B carbon black NPs; and C carbon quantum dots

Inorganic NPs

This class comprises NPs that not made of carbon or organic materials. The typical examples of this class are metal, ceramic, and semiconductor NPs. Metal NPs are purely made of metal precursors, they can be monometallic, bimetallic [ 39 ], or polymetallic [ 40 ]. Bimetallic NPs can be made from alloys or formed in different layers (core–shell) [ 39 ]. Due to the localized surface plasmon resonance characteristics, these NPs possess unique optical and electricals properties [ 25 ]. In addition, some metal NPs also possess unique thermal, magnetic, and biological properties [ 23 ]. This makes them increasingly important materials for the development of nanodevices that can be used in numerous physical, chemical, biological, biomedical, and pharmaceutical applications [ 41 , 42 ] (these applications are discussed in detail later in the applications section of the review). In present days, the size-, shape-, and facet-controlled synthesis of metal NPs is important for creating cutting-edge materials [ 43 ].

Semiconductor NPs are made of semiconductor materials, which possess properties between metals and non-metals. These NPs possess unique wide bandgaps and show significant alteration in their properties with bandgap tuning compared to bulk semiconductor materials [ 25 ]. As a result, these NPs are important materials in photocatalysis, optic, and electronic devices [ 44 , 45 ]. Ceramic NPs are inorganic solids made of carbonates, carbides, phosphates, and oxides of metals and metalloids, such as titanium and calcium [ 46 ]. They are usually synthesized via heat and successive cooling and they can be found in amorphous, polycrystalline, dense, porous or hollow forms [ 25 ]. They are mainly used in biomedical applications due to their high stability and high load capacity [ 47 ]. Nevertheless, they are also used in other applications such as catalysis, degradation of dyes, photonics and optoelectronics [ 46 , 48 ].

Physicochemical properties of NPs

As mentioned earlier, NPs can be used in a long list of applications due to their unique physical and chemical properties that do not exist in their larger-dimension counterparts of the same materials. The following sections summarize the most import physicochemical properties that are changing on the nanoscale.

Mechanical properties

Mechanical properties refer to the mechanical characteristics of a material under different conditions, environments, and various external forces. As for traditional materials, the mechanical properties of nanomaterials generally consist of ten parts: strength, brittleness, hardness, toughness, fatigue strength, plasticity, elasticity, ductility, rigidity, and yield stress [ 49 ]. Most inorganic, non-metallic materials are brittle materials and do not have significant toughness, plasticity, elasticity, or ductility properties. Organic materials on the other hand, are flexible materials and do not necessarily have brittleness and rigidity properties.

Due to surface and quantum effects, NPs display different mechanical properties compared to bulk materials [ 49 ]. For example, conventional FeAl powder which is composed of microparticles (larger than 4 µm), is brittle, while ultrafine FeAl alloy powder displays a good combination of strength and ductility as well as enhanced plasticity [ 50 ]. These new properties are believed to arise due to the diverse interaction forces between NPs or between them and a surface. The most important interaction forces involved are van der Waals forces, which consist of three parts, Keesom force, Debye force, and London force [ 51 – 53 ]. Other relevant interaction forces are electrostatic and electrical double layer forces, normal and lateral capillary forces, solvation, structural, and hydration forces [ 54 ].

There are different theories on how the interaction forces between NPs give them new mechanical properties, such as the DLVO (Derjaguin–Landau–Verwey–Overbeek) theory, JKR (Johnson–Kendall–Roberts) theory, and DMT (Derjaguin–Muller–Toporov) theory. The DLVO theory combines the effects of van der Waals attraction and electrostatic repulsion to describe the stability of colloidal dispersions [ 54 ]. This theory can explain many phenomena in colloidal science, such as the adsorption and the aggregation of NPs in aqueous solutions and the force between charged surfaces interacting through a liquid medium [ 55 , 56 ]. Nevertheless, the DLVO theory is inadequate for the colloidal properties in the aggregated state [ 54 ].

When the size of objects decreases to the nanoscale, the surface forces become a major player in their adhesion, contact, and deformation behaviors. The JRK theory is applicable to easily deformable, large bodies with high surface energies, where it describes the domination of surface interactions by strong, short-range adhesion forces. In contrast to this, the DMT theory is applicable to very small and hard bodies with low surface energies, where it describes the adhesion being caused by the presence of weak, long-range attractive forces. Although the DLVO, JKR and DMT theories have been widely used to describe and study the mechanical properties of NPs [ 57 , 58 ], it is still a matter of debate whether or not continuum mechanics can be used to describe a particle or collection of particles at the nanometer scale [ 54 ].

Thermal properties

Heat transfer in NPs primarily depends on energy conduction due to electrons as well as photons (lattice vibration) and the scattering effects that accompany both [ 59 ]. The major components of thermal properties of a material are thermal conductivity, thermoelectric power, heat capacity, and thermal stability [ 59 , 60 ].

NP size has a direct impact on electrical and thermal conductivity of NPs [ 60 ]. As the NP size decreases, the ratio of particle surface area respective to its volume increases hyperbolically [ 60 ]. Since the conduction of electrons is one of the two main ways in which heat is transferred, the higher surface-to-volume ratio in NPs provides higher number of electrons for heat transfer compared to bulk materials [ 61 ]. Moreover, thermal conductivity in NPs is also promoted by microconvection, which results from the Brownian motion of NPs [ 62 ]. Nevertheless, this phenomenon only happens when solid NPs are dispersed in a liquid (generating a Nanofluid) [ 63 ]. As an example, the addition of Cu NPs to ethylene glycol enhances the thermal conductivity of the fluid up to 40% [ 64 ].

The thermoelectric power of a material depends on its Seebeck coefficient and electrical conductivity ( P = S 2 σ , where P is thermoelectric power, S is the Seebeck coefficient, and σ is the electrical conductivity). The scattering of NPs in bulk materials (doping) is known to enhance the thermoelectric power factor [ 65 ]. This enhancement could come from the enhancement of the Seebeck coefficient or the enhancement of electrical conductivity. The embedding of size-controlled NPs in bulk thermoelectric materials helps to reduce the lattice thermal conductivity and enhances the Seebeck coefficient due to electron energy filtering [ 66 , 67 ]. Generally, the enhancement of electrical conductivity is accompanied by the reduction of the Seebeck coefficient and vice versa [ 65 ] However, the doping of InGaAlAs material with 2–3 nm Er NPs resulted in the significant increase of thermoelectric power of the material through the enhancement of the conductivity while keeping the Seebeck coefficient unchanged [ 65 ]. Depending on NP size, volume fraction, and band offset, a NP-doped sample can either enhance or suppress the electrical conductivity in comparison with undoped bulk sample.

Experimental studies have shown that the heat capacity of NPs exceeds the values of analogous bulk materials by up to 10% [ 68 ], e.g. in the case of Al 2 O 3 and SiO 2 NPs [ 69 , 70 ]. The major contribution to heat capacity at ambient temperatures is determined by the vibration degrees of freedom, i.e., the peculiarities of phonon spectra (vibrational energy that arises from oscillating atoms within a crystal) are responsible for the anomalous behavior of heat capacity of NPs [ 68 ]. NPs usually exhibit a significant decrease in melting temperature compared to their analogous bulk materials [ 71 ]. The main reason for this phenomenon is that the liquid/vapor interface energy is generally lower than the average solid/vapor interface energy [ 72 ]. When the particle size decreases, its surface-to-volume ratio increases, and the melting temperature decreases as a result of the improved free energy at the particle surface [ 73 ]. For instance, the melting temperature of 3 nm Au NPs is 300 degrees lower than the melting temperature of bulk gold [ 14 ]. In addition, NP composition plays an important role in thermal stability. For example, the thermal stability of Au in Au 0.8 Fe 0.2 is significantly higher than of pure Au or Au 0.2 Fe 0.8 [ 74 ]. Generally, bimetallic alloy NPs show higher thermal stabilities and melting temperatures than monometallic NPs due to the alloying effect [ 75 , 76 ].

Magnetic properties

All magnetic compounds include a ‘magnetic element’ in their formula, i.e., Fe, Co, or Ni (at ambient temperatures). There are only three known exceptions that are made from mixed diamagnetic elements, Sc 3 In, ZrZn 2 , and TiBe 2-x Cu x [ 77 – 80 ]. Otherwise, elements such as Pd, Au, or Ag are diamagnetic. This all changes in the nanoscale. Several materials become magnetic in the form of NPs as a result of uneven electronic distribution [ 25 ]. For instance, FeAl is not magnetic in bulk but in the form of NPs, it is becomes magnetic [ 50 ], other examples include Pd and Au [ 81 ]. In bulk materials, the key parameters for determining magnetic properties are composition, crystallographic structure, magnetic anisotropy, and vacancy defects [ 82 , 83 ]. However, on the nanoscale, two more important parameters are strongly involved, i.e., size and shape [ 84 ].

One of the interesting size-dependent phenomena of NPs is superparamagnetism [ 84 ]. As the size of the NPs decreases, the magnetic anisotropy energy per NP decreases. The magnetic anisotropy energy is the energy keeping the magnetic moment in a particular orientation. At a characteristic size for each type of NPs, the anisotropy energy becomes equal to the thermal energy, which allows the random flipping of the magnetic moment [ 85 ], in this case, the NP is defined as being superparamagnetic [ 86 ]. Superparamagnetic NPs display high magnetization only in the presence of a magnetic field, and once it is removed they do not retain any magnetization [ 87 ]. Superparamagnetism was long believed to form only in small ferromagnetic or ferrimagnetic NPs [ 88 ], but interestingly, other paramagnetic materials show magnetism in the nanoscale too [ 81 ].

NP size effects can also be observed in changes in magnetic coercivity, i.e., the resistance of a magnetic material to changes in magnetization (Fig.  4 ). In contrast to large particles or bulk materials, which possess multiple magnetic domain structures, small NPs possess single magnetic domain structures below a certain critical radius (r c ), where all magnetic spins in the NP align unidirectionally (blue arrows in Fig.  4 ). However, the NP radius has to be lower than the threshold radius for superparamagnetism (r sp ) in order to be superparamagnetic [ 89 ]. In the single-domain regime, between r sp and r c , the magnetic coercivity increases as the size of the NP increases until it reaches the maximum at r c [ 84 ]. In this size regime, due to the high magnetic coercivity, the NPs behave similarly as their larger dimension counterparts despite having a single domain structure, i.e., they become ferromagnetic for ferromagnetic materials or paramagnetic for paramagnetic materials etc . Above r c , the magnetic coercivity starts to decrease when multiple magnetic domains are formed in a single NP. The critical radius represents the size where it is energetically favored for the NP to exist without a domain wall [ 86 ]. The calculated critical radii for some common magnetic materials are 35 nm of Ni, 8 nm for Co, and 1 nm for Fe [ 90 ]. Above that point, multi-domain magnetism begins in which a smaller reversal magnetic field is required to make the net magnetization zero [ 84 ].

An external file that holds a picture, illustration, etc.
Object name is 12951_2022_1477_Fig4_HTML.jpg

The change in magnetic coercivity of NPs as a function of particle radius. Figure adapted from Kalubowilage et al., 2019 [ 89 ]. rc critical radius, rsp threshold radius for superparamagnetism

The second key parameter for determining the magnetic properties of NPs is the shape of NPs. In comparison to the size parameter, there is significant less research on the effect of shape on the magnetic properties of NPs having the same volume [ 86 ]. However, large differences in coercivity were found between a set of cubic and spherical CoFe 2 O 4 NPs [ 91 ]. Unlike the curved topography in spherical CoFe 2 O 4 NPs, cubic CoFe 2 O 4 NPs have fewer missing oxygen atoms, and it was hypothesized that this led to less surface pinning and to lower coercivity for the cubic structures [ 86 ]. Other studies also found differences in magnetism between spherical and cubic Fe 3 O 4 NPs [ 92 , 93 ].

Similar to bulk materials, the composition also affects the magnetism of NPs. The magnetocrystalline phase of the NP is significant in determining its magnetic coercivity [ 94 ]. This effect can be observed in magnetic bimetallic core–shell or alloy NPs with anisotropic crystalline structures. For example, Co@Pt core–shell NPs composed of an isotropically structured face-centered cubic Co core and a non-magnetic Pt shell exhibit superparamagnetic behavior with zero coercivity at room temperature [ 95 ]. In general, the compositional modification of NPs by the adoption of magnetic dopants is known to significantly change the magnetism of NPs [ 96 ].

Electronic and optical properties

Metallic and semiconductor NPs possess interesting linear absorption, photoluminescence emission, and nonlinear optical properties due to the quantum confinement and localized surface plasmon resonance (LSPR) effect [ 97 , 98 ]. LSPR phenomena arise when the incident photon frequency is constant with the collective excitation of the conductive electrons [ 25 ].Due to this phenomenon, noble metal NPs exhibit a strong size-dependent UV–visible extinction band that is not present in the spectra of bulk metals. Generally, the optical properties of NPs depend on the size, shape, and the dielectric environment of the NPs [ 99 ].

The collective excitations of conductive electrons in metals are called plasmons [ 100 ]. Depending on the boundary conditions, bulk plasmons, surface-propagating plasmons, and surface-localized plasmons are distinguished (Fig.  5 A–C). Because of their longitudinal nature, the bulk plasmons cannot be excited by visible light. The surface-propagating plasmons propagate along metal surfaces in a waveguide-like fashion [ 98 ]. In the case of NPs, when they are irradiated by visible light, the oscillating electric field causes the conductive electrons to oscillate coherently. When the electron cloud is displaced relative to the nuclei, a restoring force rises from Coulomb attraction between electrons and nuclei that results in oscillation of the electron cloud relative to the nuclear framework [ 99 ]. This creates uncompensated charges at the NP surface (Fig.  5 D). As the main effect producing the restoring force is the polarization of the NP surface, these oscillations are called surface plasmons and have a well-defined resonance frequency [ 98 ].

An external file that holds a picture, illustration, etc.
Object name is 12951_2022_1477_Fig5_HTML.jpg

Graphical illustration of the types of plasmons. A bulk; B surface propagating; and C surface localized plasmons (adapted from Khlebtsov et al., 2010 [ 98 ]). D graphical illustration of the localized surface plasmon resonance (LSPR) in NPs (adapted from Kelly et al., 2003 [ 99 ])

Experimental studies on Ag NPs showed significant differences in their optical properties based on the size of NPs. For Ag NPs with 30 nm radius, the main extinction peak was at 369 nm wavelength, while for Ag NPs with 60 nm radius, a totally different behavior was observed [ 99 ]. The same researchers found that the shape of the NPs also is critical for the optical properties, the plasmon resonance wavelength shifts to the red as the NPs become more oblate [ 99 ], demonstrating that plasmon resonance strongly depend on NPs shape. With respect to the dielectric environment of the NPs, both the surrounding solvent and the support (substrate) were found to be critical for the optical properties. For Ag NPs, both experimental and theorical studies on the effect of surrounding solvent show that plasmon wavelength linearly depends on the refractive index of the solvent [ 99 , 101 ]. At the same time, 10 nm Ag NPs supported on mica substrates displayed LSPR wavelength shifts to the red compared to unsupported NPs [ 102 ]. The biogenic synthesis of NPs can also improve the optical properties. Biologically produced CeO 2 NPs using Simarouba glauca leave extract were found to have different absorption bands and higher band gap energies compared to chemically produced CeO 2 NPs. These superior optical properties were attributed to the better crystallinity and small size of biogenic NPs compared to chemical NPs [ 103 ]. Biogenic NPs can also offer higher photocatalytic activities, e.g., ZnO NPs produced by Plectranthus amboinicus leaf extract had higher photocatalytic activity in the photodegradation of methyl red under UV illumination compared to chemical produced ZnO NPs [ 104 ].

Catalytic properties

Nano-catalysis, i.e., the use of NPs as catalysts, is a quickly evolving field within chemical catalysis. Significantly enhanced or novel catalytic properties such as reactivity and selectivity have been reported for NP catalysts compared to their bulk analogues. The catalytic properties of NPs depend on the size, shape, composition, interparticle spacing, the oxidation state, and the support of the NPs [ 76 ].

The dependency of catalytic activity on the size of NPs is well studied. The relation is an inverse one, i.e., the smaller the NPs the more catalytically active they are. This relationship was found e.g., in the electro-catalysis oxidation of CO by size-selected Au NPs (1.5, 4, and 6 nm) deposited on indium tin oxide. The researchers observed that the smallest NPs provided the highest normalized current densities [ 105 ]. The same relationship was also found in several other studies [ 106 – 110 ]. Goodman et al., 1998 [ 111 ] speculated originally that this behavior could be attributed to quantum-size effects generated by the confinement of electrons within a small volume. Later, size-dependent changes in the electronic structure of the clusters [ 112 ] and the resulting larger number of low-coordinated atoms available for interaction by the larger surface-to-volume ratios with smaller NPs were discussed [ 76 ].

The shape is also known to affect the reactivity and selectivity of the NPs. For the oxidation of CO by Au NPs, hemispherical NPs were found to be more active than spherical ones [ 113 ]. For the oxidation of styrene by Ag NPs, nanocubes were found to be fourteen times more efficient than nanoplates and four times more efficient than nanospheres [ 114 ]. The reason for these dramatical changes are attributed to the increase/decrease in the relative area of the catalytically active surface facets [ 76 ] or to the differences in stability for different NP shapes [ 115 ].

As for composition, several studies have shown that the use of alloys in NPs can enhance the catalytic activity as a result of the alloying effect causing changes in the electronic properties of the catalyst, decreasing poisoning effects, and providing distinct selectivities [ 76 ]. For example, the alloying of Pt with other metals such as Ru, Ni, and Co, was reported to enhance the hydrogenation and oxygen reduction activity of the NP catalyst material, as well as enhancing the resistance against CO poisoning [ 116 – 118 ]. However, the alloying of Pt with Fe, Ru, and Pd, resulted in reduced reactivity for methanol decomposition [ 119 ]. This reduction in reactivity was explained by the possible occupation of the surface with the addition metal atoms, since pure Fe, Ru, and Pd clusters are less reactive for methanol decomposition than similarly-sized pure Pt clusters. In general, the change in the composition of NPs changes the electronic structure of metal surfaces by the formation of bimetallic bonds as well as the modification of metal–metal bond lengths [ 76 ]. In addition, the charge-transfer phenomenon between different metals may favorably change the binding energy of adsorbents, lower the barriers for specific chemical reactions, and enhance resistance against poisoning [ 120 – 122 ].

The catalytic activity and stability of 2 nm Au NPs dispersed on polycrystalline TiC films displayed a strong dependence on interparticle spacing. In this study, Au NPs having two different interparticle spacing (30 and 80 nm) were analyzed by Thermal Desorption Spectroscopy. It was found that the sample with smaller interparticle spacing was poisoned and subsequently deactivated while the sample with longer interparticle spacing showed longer lifetime [ 123 ]. At the same time, the oxidation state of NPs was shown to affect the catalytic activities. Ru NPs under rich O 2 conditions and moderate temperatures oxidize and form RuO 2 , the reaction of CO oxidation was found to occur on the metal oxide surface not the metal surface [ 124 ]. A similar effect on CO oxidation was also observed with Pt NPs in which the reactivity of PtO 2 was found to be higher than Pt [ 125 ]. The reaction of CO oxidation was compared for several metal NPs (Ru, Pd, Ir, Os, and Pt) and their corresponding oxides, and the oxides were indeed more reactive than the metals [ 126 , 127 ]. The superior catalytic performance of RuO 2 over their metallic counterparts is generally agreed on, nevertheless, the same cannot be said for other catalytically active metals such as Pt [ 76 ]. In general, these differences in catalytic performance are attributed to the electron transfer processes at the metal/metal oxide interfaces. Consequently, the view that NP oxidation is an undesirable process that leads to the reduction of catalytic performance needs to be reconsidered [ 128 ].

An example for the effect of the support material is the role of the MgO support for Au NPs, where MgO was found to be important for CO oxidation and particularly, for controlling the rate of CO oxidation through oxygen vacancies [ 129 ]. Later, the process of electron charge transfer from oxygen vacancies at the metal-substrate interface of supported Au NPs was suggested to be an ideal environment for O 2 activation and oxidation reactions [ 130 ]. A similar behavior was also found in the decomposition of SO 2 and dissociation of water by Au NPs supported on CeO 2 , in which CeO 2 supports played a critical role [ 131 ]. The experiments showed that not only the chemical composition of the support affects the reactivity of the catalyst, but the crystal structure of the support, too [ 132 ]. Enhanced catalytic performance for CO oxidation and SO 2 dissociation have also been reported for Au NPs supported on metal carbides such as TiC [ 108 , 133 ]. In addition to enhanced catalytic reactivities, the support also plays an important role in NP stabilization [ 106 ], i.e., the stabilization of NPs against coarsening, the stabilization of metal oxides at the NP surface, and the stabilization of intermediate reactions species [ 76 ].

Characterization of NPs

The properties of NPs determine their potential applications. Hence, different methods and techniques are used for the analysis and characterization of the various physicochemical properties of NPs. Table ​ Table1 1 summarizes all characterization techniques mentioned in this review and shows what properties and features can be resolved by each technique.

Common techniques and methods used for NP characterization

TechniqueProperties and features that can be resolved by each technique
SizeShapeDispersityLocalizationAgglomerationSurface morphologySurface areaPore sizeLiterature
Morphological and topographicalTEM[ , ]
SEM[ , ]
STM[ , ]
DLS[ – ]
NTA[ , ]
BET[ – ]
BJH[ – ]
TechniqueCompositionPhaseCrystallinityFunctionalizationOxidationSurface chargePolarityBondingElectrochemicalLiterature
Structural and chemicalXRD[ , ]
EDX[ – ]
HAADF[ – ]
XPS[ – ]
FTIR[ , ]
Zeta potential[ – ]
CV[ , ]
Raman spectroscopy[ , ]
TechniqueToughnessTensile strengthCompressive strengthElasticityViscoelasticityHardnessStiffnessLiterature
MechanicalUTM[ , ]
Nano-indentation[ , ]
DMA[ , ]
TechniqueAbsorptionReflectanceFluorescenceLuminescenceBandgapElectronic statePhotoactivityElectrical conductanceLiterature
Optical, electronic, and electricalRaman spectroscopy[ , ]
SERS[ ]
UV–vis[ – ]
PL[ – ]
DRS[ – ]
Ellipsometry[ , ]
TechniqueSaturation magnetizationRemnant magnetizationCoercivityg-factorMagnetic field intensityMagnetic forceMagnetic susceptibilityLiterature
MagneticMFM[ – ]
VSM[ , ]
SQUID✓`[ , ]
ESR[ , ]
TechniqueMelting pointCrystallization pointStructural-phase transitionHeat capacityThermal conductivityThermal StabilityOxidative stabilityLiterature
ThermalDSC[ , ]
DTA[ , ]
TGA[ , ]
THW[ , ]

The physicochemical properties and features that can be resolved by each technique or method are shown together with examples of experimental research from literature

Morphological and topographical characterization

The morphological and topographical features of NPs are of great interest since they influence most of the properties of NPs as described above. These features include the size, shape, dispersity, localization, agglomeration/aggregation, surface morphology, surface area, and porosity of the NPs. The following techniques are regularly used for the characterization of morphological and topographical features of NPs.

Electron microscopy (EM)

Scanning electron microscopy (SEM), scanning tunneling microscopy (STM), and transmission electron microscopy (TEM) are frequently employed for the analysis of NP size, shape, and surface. In SEM, an electron gun is used to produce a beam of electrons that is controlled by a set of lenses to follows a vertical path through the microscope until it hits the samples. Once the sample is hit by the beam, electrons and X-rays are ejected from the sample. Detectors are then used to collect the X-rays and scattered electrons in order to create a 3D image of the sample. SEM provides different information about the NPs such as size, shape, aggregation, and dispersion [ 134 ]. Similarly, TEM provides information about the size, shape, localization, dispersity, and aggregation of NPs in two-dimensional images [ 25 ]. TEM employs an electromagnetic lens that focuses a very fine beam of electrons into an ultrathin section of the sample. This beam passes through the specimen where the electrons either scatter or penetrate the sample and hit a fluorescent screen at the bottom of the microscope. The difference in electron densities is used for the contrast to create an image of the specimen. TEM can be also used for the characterization of NP crystal structure through the use of selected area electron diffraction (SAED), where the electron beam is focused on a selected area in the sample and the scattered electrons are used to obtain a diffraction pattern. STM is based on the phenomenon of quantum tunneling, where a metallic tip is brough very close to the sample surface and used to apply voltage. When voltage is applied, electrons from the sample surface are extracted creating an electrical current that is used to reconstruct an image of the surface with atomic resolution [ 135 ]. STM is mainly used to characterize the topography of NPs. For inorganic NPs, these techniques offer excellent approaches for the determination of morphological features of NPs. For organic NPs (or NPs coated with biological materials), these techniques require sophisticated sample preparations which constitute major restrictions to their use [ 136 ]. The sample preparation for these techniques might cause sample dehydration, which might lead e.g. to sample shrinking and aggregation [ 136 ].

Examples: TEM was used for the characterization of Ag NPs produced by Arbutus unedo leaf extract. In this example, the NPs have a spherical morphology with a uniform size of 30 nm. The NPs were found to agglomerate into small aggregates, each including 5–6 NPs. At the same time, the SAED approach was used to determine the crystal structure of the NPs. The majority of the NPs were found to be single crystalline cubic materials predominately oriented along their (111) direction [ 137 ]. For the characterization of Ag NPs produced by Diospyros kaki leaf extract, SEM helped to show that the NPs were also spherical and the size was 32 nm with some deviations [ 138 ]. STM is less frequently used for the characterization of biogenic NPs. The features of Ag NPs produced by lime, sweet-lime, and orange juices were compared using STM technique [ 139 ].

Dynamic light scattering (DLS)

This technique is a common approach for the analysis of NP size and size distribution. This approach involves the measurement of light interference based on the Brownian motion of NPs in suspension, and on the correlation of NP velocity (diffusion coefficient) with their size using Strokes-Einstein equation [ 140 ]. The size distribution range of NPs is shown as the polydispersity index, which is the output of an autocorrelation function [ 136 ]. The polydispersity index values lie between 0 and 1, where 0 represents a completely homogenous population and 1 represents a highly heterogeneous population. This technique also allows the analysis of non-spherical NPs through the use of multistage DLS [ 136 ]. This technique is also referred to as photon correlation spectroscopy (PCS) [ 141 ].

Examples: DLS was used to measure the size and the size distribution profile of a wide range of biogenic NPs. The average size of Ag NPs produced by Trichoderma koningii fungi was found to be around 25 nm and the size distribution profile was between 14 and 34 nm. The polydispersity index for those NPs was 0.681, which indicates that they are polydispersed [ 142 ]. While the average size of Ag NPs produced by potato ( Solanum tuberosum ) was found to be around 10–12 nm with a wider distribution profile between 3–65 nm [ 143 ]. In a different application, DLS was employed to study the size increase of biogenic MnO 2 NPs overtime, demonstrating that their size is 7.5 nm after 3 min of the initiation of the reaction, then their size grows overtime until it become 54 nm after 31 min [ 144 ].

Nanoparticle tracking analysis (NTA)

This method is used for the analysis of NP size in suspensions based on their Brownian motion. Like in DLS, the rate of NP movement is correlated with their size using Strokes-Einstein equation, allowing the measurement of size distribution profiles for NPs with 10–1000 nm diameter. Its advantage over DLS is that NP motion is analyzed by video. Individual positional changes of NPs are tracked in two dimensions, which are used to determine NP diffusion rates, and by knowing the diffusion coefficient, the hydrodynamic diameter of the particles can be calculated. In DLS, individual NPs are not visualized, but instead, the time-dependent intensity fluctuations caused by Brownian motion are used to calculate the polydispersity index [ 145 ]. NTA was found to be more precise for sizing monodisperse as well as polydisperse organic NPs compared to DLS [ 146 ].

Examples: NTA was used to measure the size and dispersity of Ag NPs produced by Camellia sinensis (green tea) powder, the NPs were found to be well dispersed in an aqueous medium with an average size of 45 ± 12 nm [ 147 ]. For Se NPs produced by lactic acid bacteria, NTA was employed to measure the size and the concentration of NPs. The average size was found to be 187 ± 56 nm with a concentration of (4.67 ± 0.30) × 10 9 Se NPs per ml [ 148 ].

Brunauer–Emmett–Teller (BET) method

This method is based on the adsorption and desorption principle developed by Stephen Brunauer, Paul Emmett, and Edward Teller, and it is considered one of the best methods for the analysis of NP surface area [ 25 ]. In BET analysis, a partial vacuum is created to produce adsorption between the sample and liquid N 2 (because the interaction between solid and gaseous phases is weak, the surface is cooled with liquid N 2 to obtain detectable amounts of adsorption). After the formation of adsorption monolayers, the sample is removed from the N 2 atmosphere and heated to cause the adsorbed N 2 to be released from the material (desorption) and quantified. The data collected is displayed in the form of isotherms (graphs representing the amount of N 2 adsorbed as a function of relative pressure at a constant temperature). The data is displayed in five isotherms where the information is used to determine the surface area of the sample [ 25 , 149 ]. Figure  6 graphically illustrates the principle of this method.

An external file that holds a picture, illustration, etc.
Object name is 12951_2022_1477_Fig6_HTML.jpg

Principles of the BET and BJH methods. The BET method (steps 1–3) is based on the adsorption of nitrogen on the NP surface. After the formation of a monolayer, nitrogen is desorbed, and the surface area is calculated. The BJH method (steps 1, 2, 4, and 5) is based on the complete filling of NP pores with liquid nitrogen. When saturation is reached, nitrogen is desorbed, and pore size is calculated

Examples: The BET method was employed to measure the surface area of CeO 2 NPs produced by Eucalyptus globulus leaf extract. The surface area was found to be 40.96 m 2 /g of biogenic CeO 2 NPs, much higher than the commercial CeO 2 NPs (8.5 m 2 /g) [ 150 ]. BET was also used to measure the surface area of SiO 2 NPs produced by rice husk, CuO NPs produced by Leucaena leucocephala leaf extract, and Ag NPs produced by Acanthospermum hispidum leaf extract. In these examples, the surface area was 7.15 m 2 /g, 47.54 m 2 /g, and 9.91 m 2 /g, respectively [ 151 – 153 ].

Barrett–Joyner–Halenda (BJH) method

This method is based on the Barrett–Joyner–Halenda principle and is used for the determination of porosity (or pore size) of NPs. Similar to the BET method, this method also involves the use of N 2 gas to adsorb to the sample. In the BJH method, the process is extended so the gas condensates in the sample pores as pressure increases. The pressure is increased until a saturation point is achieved, at which all the pores of the sample are filled with liquid. Afterwards, the condensated gas is allowed to evaporate where the desorption data is calculated and correlated to the pore size using a modified Kelvin equation (Kelvin model of pore filling) [ 154 , 155 ]. Figure  6 graphically illustrates this method.

Examples: The BJH method was employed to study the pore size of a wide range of biogenic NPs, for instance, the pore size of CeO 2 NPs produced by Eucalyptus globulus leaf extract was found to be 7.8 nm [ 150 ], the pore size of CuO NPs produced by Leucaena leucocephala leaf extract was 2.13 nm [ 152 ], the pore size of SiO 2 NPs produced by rice husk and Ag NPs produced by Acanthospermum hispidum leaf extract were much larger, being 29.63 nm and 36.34 nm, respectively [ 151 , 153 ].

Structural and chemical characterization

The structural characterization of NPs and the study of their composition is of high interest due to the strong influence of these parameters on the physicochemical properties. The following techniques are commonly used for the analysis of NP composition, phase, crystallinity, functionalization, chemical state (oxidation), surface charge, polarity, bonding, and electrochemical properties.

X-ray diffraction analysis (XRD)

This technique is based on irradiating a material with incident X-rays and then measuring the intensities and scattering angles of the X-rays that leave the material [ 156 ]. This technique is widely used for the analysis of NP phase and crystallinity. However, the resolution and accuracy of XRD can be affected in cases where the samples have highly amorphous characteristics with varied interatomic distances or when the NPs are smaller than several hundreds of atoms [ 25 ].

Examples: For the characterization of biogenic Ag NPs, the XRD results of Ag NPs produced by Trichoderma koningii [ 142 ], Solanum tuberosum [ 143 ], and Acanthospermum hispidum leaf extract [ 153 ] displayed characteristic peaks occurring at roughly 2θ = 38 o , 44°, and 64 o corresponding to (111), (200), and (220) planes, respectively. These results are in good agreement with the reference to the face-centered cubic structure of crystalline silver. However, the XRD results of Ag NPs produced by Solanum tuberosum were not as clear as the other biogenic Ag NPs and had several impurities. The structural characterization of Pd NPs produced by Garcinia pedunculata Roxb leaf extract by XRD showed the distinct peaks of Pd, however, three other peaks were also observed at 2θ of 34.22˚, 55.72˚, and 86.38˚, indicating the presence of PdO phases along with Pd NPs [ 157 ].

Energy-dispersive X-ray spectroscopy (EDX)

This technique is based on the irradiation of the sample with an electron beam. Electrons of the electron beam when incident on the sample surface eject inner shell electrons, the transition of outer shell electrons to fill up the vacancy in the inner shell produces X-rays. Each element produces a characteristic X-ray emission pattern due to its unique atomic structure, and therefore can be used to perform compositional analysis [ 158 ]. The shortfall of EDX is that the resulting spectra give only qualitative compositional information (it shows the chemical elements present in the sample without quantification). However, the peak intensities to some extent give an estimate of the relative abundance of an element in a sample [ 159 ]. This technique does not require sophisticated additional infrastructures, usually it is a small device that is connected to an existing SEM or TEM. This allows the use of SEM or TEM for the morphological characterization and EDX is used simultaneously for the analysis of chemical composition [ 160 ].

Examples: The EDX technique is usually used for the confirmation of the presence of the element in question in biogenic NPs. For instance, EDX was used to confirm the presence of Au in Au NPs produced by Jasminum auriculatum leaf extract [ 161 ], the presence of Pd in Pd NPs produced by Pulicaria glutinosa extract [ 162 ], the presence of Te in Te NPs produced by Penicillium chrysogenum PTCC 5031 [ 163 ], and the presence of Ag in Ag NPs produced by Trichoderma viride [ 164 ].

High-angle annular dark-field imaging (HAADF)

This method is used for the elemental mapping of a sample using a scanning transmission electron microscope (STEM). The images are formed by the collection of incoherently scattering electrons with an annular dark-field detector [ 165 ]. This method offers high sensitivity to variations in the atomic number of elements of the sample, and it is used for elemental composition analysis usually when the NPs of interest consist of relatively heavy elements. The contrast of the images is strongly correlated with atomic number and specimen thickness [ 166 ].

Examples: The employment of HAADF-STEM in the characterization of biogenic Au–Ag–Cu alloy NPs confirmed the presence of the three elements in the same NP [ 167 ]. Similarly, this approach revealed that Ag NPs produced by Andrographis paniculata stem extract were coated with an organic polymer [ 168 ]. The employment of this approach in the characterization of Cu NPs produced by Shewanella oneidensis revealed that Cu NPs remained stable against oxidization under anaerobic conditions, but when they were exposed to air a thin shell of Cu 2 O develop around the NPs [ 169 ].

X-ray photoelectron spectroscopy (XPS)

This technique is considered the most sensitive approach for the determination of NP exact elemental ratios, chemical state, and exact bonding nature of NP materials [ 25 ]. XPS is based on the photoelectric effect that can identify the elements within a material, or covering a material, as well as their chemical state with high precision [ 170 ]. XPS can also be used to provide in-depth information on electron transfer, e.g., for Pt NPs supported on CeO 2 , it was found that per ten Pt atoms only one electron is transferred to the support [ 171 ].

Examples: The XPS technique can employed for different purposes. For instance, it was used for measuring the purity of Au NPs produced by cumin seed powder [ 172 ]. XPS was used for the determination of the oxidation states of Pt NPs produced by Nigella sativa seeds and Ag NPs produced by Rosa canina . XPS results of Pt NPs showed the presence of three oxidation states for Pt (Pt (0), Pt (II), and Pt (IV)) and two oxidation states for Ag NPs (Ag (0) and Ag (I)). In both cases, the zero-oxidation state was the abundant one, the presence of a small amount of the other oxidation states suggests that some of the NPs were oxidized or had unreduced species [ 173 , 174 ]. XPS was used for the determination of the exact elemental ratios and the bonding nature of FeS NPs produced by Shewanella putrefaciens CN32. For the exact elemental ratios, the researchers compared biogenic and abiotic FeS NPs and found that biogenic FeS NPs had a 2.3:1 Fe:S ratio while the abiotic NPs had a 1.3:1 Fe:S ratio. For the bonding nature, it was determined that the surface of NPs had Fe(II)-S, Fe(III)-S, Fe(II)-O, and Fe(III)-O bonds [ 175 ].

Fourier-transform infrared spectroscopy (FTIR)

This technique is based on irradiating a material with infrared light, where the absorbed or transmitted radiation is recorded. The resulting spectrum represents a unique fingerprint of samples, where information about the nature of the sample can be obtained such as the bonds involved, polarity, and oxidation state of the sample [ 176 , 177 ]. This technique is mainly used for the characterization of organic materials such as the surface chemical composition or functionalization of NPs. It is also used for the identification of contaminants when high purity is sought [ 178 ].

Examples: For biogenic NPs, FTIR is usually used for the identification of probable functional groups present on the surface of NPs that are responsible for the reduction and stabilization of the NPs. For plant-mediated NP synthesis, for instance for Ag NPs produced by Camellia sinensis , the FTIR results indicate the presence of Camellia sinensis phytocompounds, such as caffeine and catechin, on the surface of Ag NPs that could be responsible for the reduction of Ag or act as stabilizing agents [ 147 ]. For Ag NPs produced by Solanum tuberosum , the NPs were found to be capped by amide and amine groups [ 143 ]. For CeO 2 NPs produced by Eucalyptus globulus , the polyphenol groups present in Eucalyptus globulus extract were found on the surface of NPs suggesting their involvement in the reduction/stabilization process [ 150 ]. For microbe-mediated NP synthesis, FTIR results show the presence of protein residues on the surface of NPs confirming the involvement of different proteins in the reduction/stabilization process, such as in Ag NPs produced by Streptomyces sp. NH28 [ 179 ], in Te NPs produced by Penicillium chrysogenum PTCC 5031 [ 163 ], and in Se NPs produced by Azospirillum thiophilum [ 180 ].

Zeta potential analysis

Zeta potential measurements are used for the determination of NP surface charge in colloidal solutions. The surface charge of NPs attracts counter-ions that form a thin layer on the surface of the NPs (called Stern layer). This layer travels with the NPs as they diffuse thought the solution. The electric potential at the boundary of this layer is known as NP zeta potential [ 136 ]. The instruments used to measure this potential are called zeta potential analyzers [ 181 ]. Zeta potential values are indicative for NP stability, where higher absolute value of zeta potential indicate more stable NPs [ 136 ].

Examples: The zeta potential is a good indicator for the stability of NPs, where NPs with zeta potentials of more than + 30 mV or less than − 30 mV are considered stable. Zeta potentials have been measured for a wide range of biogenic NPs. The zeta potential for Ag NPs produced by Ziziphus jujuba leaf extract of − 26.4 mV [ 182 ]. Ag NPs produced by other organisms have different zeta potential values, for example, Ag NPs produced by Punica granatum peel extract have a zeta potential of − 40.6 mV indicating their higher stability [ 183 ], while Ag NPs produced by Aspergillus tubingensis have a zeta potential of + 8.48 indicating their relative instability [ 184 ]. The pH of the sample is another important parameter for zeta potential values, the higher pH the lower the zeta potential value [ 185 ]. Having different zeta potential values for the same type of NPs depending on the organism used for their synthesis is not unique to silver, Se NPs also show different potential values depending on the organism used for their synthesis [ 186 ].

Cyclic voltammetry (CV)

CV is an electrochemical technique for measuring the current response of redox-active solutions to a linearly cycled potential sweep between two or more set values. The CV technique involves the use of three electrodes: a working electrode, reference electrode, and counter electrode. These electrodes are introduced to an electrochemical cell filled with an electrolyte solution and where voltage is in excess, the potential of the working electrode is cycled and the resulting current is measured. This technique is used for determining information about the reduction potential of materials, the kinetics of electron transfer reactions, and the thermodynamics of redox processes [ 187 – 189 ].

Examples: The CV technique can be employed for two different purposes in the context of biogenic NP characterization. Firstly, it can be used for measuring the stability of NPs in electrocatalysis. For this purpose, the biogenic NPs are assembled on an electrode of the electrolysis cell and are tested for their electrocatalytic behavior against a redox reaction over different cycles. As an example, Ag NPs produced by Citrus sinensis were found to be stable in phenolic compounds redox reactions over multiple cycles [ 190 ]. Secondly, CV can be used for monitoring the progress of reduction of metallic NPs or for the determination of the reducing agent involved in the reduction. For example, for Ag NPs produced by Indian propolis, four cyclic voltammograms were recorded, one for a water extract of Indian propolis, another for an ethanol extract of Indian propolis, and two for the constituent flavonoids of Indian propolis (pinocembrin and galangin). The four cyclic voltammograms showed similar behaviors indicating the involvement of these flavonoids in the reduction of Ag and in forming Ag NPs [ 191 ].

Raman spectroscopy

This technique is based on irradiating a sample with monochromatic light emitted by a laser, in which the interactions between the laser light and molecular vibrations (photons and phonons) are recorded. The technique records the inelastically scattered photons, known as Raman scattering (named after the Indian physician C. V. Raman) [ 192 ]. The output of this technique is a unique fingerprint for each sample, which is used to characterize the chemical and intramolecular bonding of the sample. It can also be used to characterize the crystallographic orientation of the sample [ 193 ]. Surface-enhanced Raman spectroscopy (SERS) enhances Raman scattering of a sample and provides a more sensitive, specific, and selective technique for identifying molecular structures [ 194 ]. Both techniques are also used for the characterization of optical properties, where the recorded photons and phonons are used to understand the plasmonic resonance of NPs [ 25 ].

Examples: Raman spectroscopy was used to characterize Fe 3 O 4 NPs produced by Pisum sativum peel, the researchers found that the NPs were Fe 3 O 4 NPs with face centered cubic phase which was in agreement with their XRD measurements [ 195 ]. Other researchers used Raman spectroscopy for studying the trace deposits of carbohydrates on ferrihydrite NPs produced by Klebsiella oxytoca , the results showed that the pores of NPs had more deposits of carbohydrates that the surface of the NPs [ 196 ]. For Au NPs produced by Raphidocelis subcapitata (green algae), several biomolecules were suggested for their involvement in this process. SERS technique was used to study Au NPs surface-associated biomolecules in order to narrow down the list of biomolecules involved in the bioproduction process. The researchers found that several biomolecules such as, glutathione, β-carotene, chlorophyll a, hydroxyquinoline, and NAD were associated with Au NPs surface, thus, ruling out other molecules such as, glutaraldehyde fixing agent, saccharides, FAD, lipids, and DNA from the list [ 197 ].

Characterization of optical, electronic, and electrical properties

In addition to Raman spectroscopy and SERS, also other techniques can be employed to study and characterize the optical properties of NPs. These techniques give information about the absorption, reflectance, fluorescence, luminescence, electronic state, bandgap, photoactivity, and electrical conductance properties of NPs.

Ultraviolet–visible spectroscopy (UV–vis) and photoluminescence spectroscopy (PL)

In absorption spectroscopy such as UV–vis, the transition of electrons from the ground state to an excited state is measured, while in photoluminescence spectroscopy, the transition of electrons from the excited state to the ground state is measured [ 198 ]. UV–vis spectroscopy uses visible and UV light to measure the absorption or reflectance of a sample. In photoluminescence spectroscopy, usually UV light is used to excite the electron and then measure the luminescence or fluorescence properties of a sample [ 199 ].

Examples: UV–vis spectroscopy is a simple and common technique that is used for the characterization of the optical properties of NPs. For instance, for the characterization of the optical properties of Ag NPs produced by Trichoderma viride , the UV–vis spectrum showed that a Ag surface plasmon band occurs at 405 nm, which is a characteristic band for Ag NPs. The intensity of this band over the reaction time increased as a result of increasing Ag NP concentration in the solution. In the same study, the photoluminescence properties of these NPs were recorded, with an emission in the range between 320–520 nm, which falls in the blue-orange region [ 164 ]. For biogenic Cu NPs, the common absorption peaks are located between 530–590 nm. The difference in NP size and the bio-active molecules used for the reduction process are believed to be the reasons behind the differences in the absorption peaks [ 200 ]. For instance, 15 nm spherical Cu NPs produced by Calotropis procera have an absorption peak at 570 nm [ 201 ], while 76 nm spherical Cu NPs produced by Duranta erecta have an absorption peak at 588 nm [ 202 ]. The same applies to photoluminescence effects, where 27 nm spherical Cu NPs produced by Tilia extract emit light of 563 nm (dark brown) [ 203 ], while 19 nm spherical Cu NPs emit light of 430 nm (green) [ 204 ].

UV–vis diffuse reflectance spectroscopy (DRS)

This technique uses UV and visible light to measure the diffuse reflectance of a material (the reflection of light in many angles, as opposed to specular reflection). The resulting diffuse reflectance spectra are used to determine the electronic state of a sample, which is then used to calculate the bandgap [ 25 ]. Bandgap determination is crucial for determining conductance and photocatalytic properties especially for semiconductor NPs [ 205 ].

Examples: The DRS technique was used to calculate the bandgap for a wide range of biogenic NPs. For instance, TiO 2 NPs produced by Andrographis paniculata exhibit an optical energy bandgap of 3.27 eV [ 206 ]. Interestingly, biogenic ZnO NPs produced by different organism show different bandgaps, for example, ZnO NPs produced by Pseudomonas putida have a bandgap of 4 eV [ 207 ], while ZnO NPs produced by Calotropis procera leaf extract have a bandgap of 3.1 eV [ 208 ].

Spectroscopic ellipsometry

This technique is based on irradiating a sample with polarized light to measures changes in polarization. It is widely used to calculate the optical constants of a material (refractive index and extinction coefficient) [ 209 ]. This technique is also used to characterize the electrical conductivity and dielectric properties of materials [ 210 ].

Examples: Spectroscopic ellipsometry is not a common technique for the characterization of biogenic NPs. For chemically produced NPs, the optical properties for different-sized Au NPs partially embedded in glass substrate were measured by spectroscopic ellipsometry. In this example, a clear transition from LSPR to SPR mode was found as the thickness increases. Moreover, the partially-embedded Au NPs had much higher refractive index sensitivity compared to Au NPs fully immobilized in a glass substrate [ 211 ]. Spectroscopic ellipsometry was also used to measure the changes in the optical constants of a layer of 5 nm ZnO NPs induced by UV illumination. In this case, it was found that the UV illumination of ZnO NPs in inert atmospheres resulted in a clear blue shift in the absorption (Moss-Burstein shift). The UV illumination of ZnO NPs results in the desorption of O 2 from the NPs surface leading to the population of the lowest levels in conduction band with mobile electrons. This phenomenon is reversible, in which the exposure to O 2 from air results in the scavenging of these mobile electrons [ 212 ].

Characterization of magnetic properties

The magnetic properties of NPs are of high importance, as they potentially give NPs great advantages in catalysis, electronics, and medical applications. Several techniques were developed for the detection and quantification of small magnetic moments in NPs.

Magnetic force microscopy (MFM)

This technique is a variety of atomic force microscopy (AFM), in which a magnetic tip is used to scan the sample. The magnetic tip is approached very close to the sample, where the magnetic interactions between the tip and the sample are recorded [ 213 ]. At closer distances to the sample (0–20 nm), other forces such as van der Waals forces also interact with the tip. Therefore, MFM measurements are often operated with two-pass scanning method (also called lift height method) [ 214 ] (Fig.  7 ). In this method, the tip is firstly used to measure the topography of the sample including the molecular forces as van der Waals. Afterwards, the tip is lifted and a second scan is operated following the same topography outline. In the second scan, the short-ranged van der Waals forces disappear and the long-range magnetic forces are almost exclusively recorded. In an experimental study, researchers found that 22 nm was the optimal scanning height for the second scan, at which van der Waals forces are very weak while the distance is still small enough to measure the magnetic interactions for Pd-Fe bimetallic NPs [ 215 ].

An external file that holds a picture, illustration, etc.
Object name is 12951_2022_1477_Fig7_HTML.jpg

Magnetic force microscopy lift height method. The first scan is done very close to the surface to obtain the topography of the sample. Then, the tip is lifted and a second scan is performed following the topography outline obtained in the first scan

Examples: MFM was heavily used for the characterization of magnetite NPs produced by magnetotactic bacteria. For instance, the size and orientation of the magnetic moment of magnetite NPs produced by Magnetospirillum gryphiswaldense strain MSR-1 were studied by MFM [ 216 ], in which the size of the magnetic moment was found to be 1.61 × 10 −17 Am 2 . In a different study, MFM was used to characterize the magnetic properties and to estimate the size of the magnetic kernel of the magnetosomes produced by the same strain, and it was determined that the NPs behaved like single mono-domain nanomagnets [ 217 ]. The magnetic properties of NPs made from materials such as Pd that only exhibit significant magnetism on the nanoscale can also be studied by MFM, however, the magnetic moment of these NPs is much lower than for ferromagnetic NPs. The magnetic decoration of Pd NP samples with Fe 2 O 3 NPs strongly enhances the weak magnetic signal of Pd NPs up to 15 times [ 218 ]. This approach could make the MFM technique useful for the characterization of weak magnetic NPs.

Vibrating-sample magnetometry (VSM)

This technique measures the magnetic properties of materials based on Faraday’s law of induction. In VSM, the sample is placed in a constant magnetic field in a special holder that vibrates vertically. As the holder starts vibrating, the magnetic moment of the sample creates a magnetic field that changes as function of time. The alternating magnetic field created in the sample induces an electric current that is recorded and used to calculate the magnetic properties of the sample [ 219 , 220 ].

Examples: For the characterization of Fe 2 O 3 NPs produced by Tridax leaf extract, VSM studies revealed that the NPs had a saturation magnetization of 7.78 emu/g, a remnant magnetization of 0.054 emu/g, and a coercivity of − 1.6 G [ 221 ]. In other studies, VSM was used to compare the magnetic properties of iron oxide NPs produced Moringa oleifera with the magnetic properties of the same NPs but coated with chitosan. The researchers found that saturation magnetisation, remnant magnetization, and coercivity have lower values when the NPs are coated with chitosan [ 222 ].

Superconducting quantum interference device (SQUID) magnetometry

This technique measures the magnetic properties of materials based on the Josephson effect. Niobium (Nb) or other metal alloys are used in the device which needs to be operated at temperatures very close to the absolute zero to main superconductivity, where liquid helium is used to maintain the cold environment [ 223 ]. However, other kinds of SQUID also exist where high-temperature superconductors are used [ 224 ]. After reaching superconducting environments, the Josephson junctions contained in the device help to create a supercurrent, which is recorded and used to calculate the magnetic properties of the sample [ 225 ].

Examples: For the characterization of iron oxide NPs produced by Cnidium monnieri seed extract, SQUID magnetometry revealed that the NPs had a saturation magnetization of 54.60 emu/g, a remnant magnetization of 1.15 emu/g, a coercivity of 11 Oe, and a magnetic susceptibility of + 1.69 × 10 –3 emu/ cm 3 ⋅Oe at room temperatures, indicating the superparamagnetic behaviour of these NPs [ 226 ]. SQUID magnetometry was also used for the characterization of the magnetic properties of zinc incorporated magnetite NPs produced by Geobacter sulfurreducens , showing that the loading of only 5% zinc results in the enhancement of saturation magnetization of the NPs by more than 50% [ 227 ].

Electron spin resonance spectroscopy (ESR)

This technique measures the magnetic properties of materials by characterizing and quantifying the unpaired electrons in the sample. Electrons are charged particles that spin around their axis, which can align in two different orientations (+ ½ and − ½) when the sample is placed in strong magnetic field. These two alignments have different energies due to the Zeeman effect. Since unpaired electrons can change their spins by absorbing or emitting photons, in ESR the sample is irradiated with microwave pulses to excite electron spins until a resonance state is reached [ 228 ]. This technique is also referred to as electron paramagnetic resonance spectroscopy (EPR). It can be used to measure the ferromagnetic and antiferromagnetic properties of NPs [ 229 , 230 ].

Examples: ESR was used to characterize the magnetic properties of iron oxide NPs produced by Ficus carica . The trees naturally produce iron oxide NPs as a defence mechanism when are they are subjected to stress. The researchers found that the magnetic properties of iron oxide NPs produced by the same tree but grown in different environmental conditions have different magnetic properties. In addition, a magnetic anisotropy of the signal was visible as the magnetic properties of these NPs varied strongly at different temperatures [ 231 ]. ESR was also used to characterize the magnetic properties of Se nanomaterials produced by anaerobic granular sludge. The ESR results revealed the presence of Fe(III) atoms incorporated in the Se nanomaterial, which enhanced their overall magnetic properties, giving it ferromagnetic behaviour [ 232 ].

Characterization of thermal properties

Several techniques can be used for the characterization of the thermal properties of NPs, such as melting points, crystallization and structural-phase transition points, heat capacity, thermal conductivity, and thermal and oxidative stability.

Differential scanning calorimetry (DSC)

In this technique the analyte and a well-defined reference sample are put at the same temperature, then, the amount of heat required to increase the temperature of the sample and the reference in measured as a function of temperature. This technique is widely used to measure melting points [ 233 ], crystallization points, structural-phase transition points [ 234 ], latent heat capacity [ 235 ], heat of fusion [ 236 ], and oxidative stability [ 237 ].

Examples: For the characterization of Ag NPs produced by Rhodomyrtus tomentosa leaf extract, DSC showed three exothermic peaks at 44, 159, 243, and an endothermic peak at 441 °C. The first peak (at 44 °C) indicates that at this temperature the NPs face a gradual loss of water from their surface. The second peak (at 159 °C) shows that the thermal decomposition of the sample happens at this temperature. The last temperature (441 °C) indicates the melting temperature for those NPs [ 238 ]. For Ag NPs produced by Parthenium hysterophorus leaf extract, DSC showed that their melting temperature was at 750 °C. The researchers also found that these NPs had completely thermally decomposed and crystallized simultaneously [ 239 ].

Differential thermal analysis (DTA)

This technique is based on heating or cooling a sample and an inert reference under identical conditions, where any temperature difference between the sample and the reference is recorded. This technique is primarily used for the study of phase diagrams and transition temperatures [ 240 ]. However, it is also used to measure the melting points, thermal, and oxidative stability [ 241 , 242 ].

Thermogravimetric analysis (TGA)

This technique measures the change in the mass of a sample as a function of temperature and/or time in a controlled atmosphere [ 243 ]. This technique is mainly used to study the thermal stability of materials [ 244 ], in addition, it is also used to measure structural-phase transition points [ 245 ], thermal activation energies [ 246 ], and oxidative stability [ 247 ]. The resulting thermogram is unique for each compound and therefore can also be used for the determination of material composition [ 248 ]. TGA and DTA are usually combined in the same thermal analyzing instrument, called thermogravimetry/differential thermal analysis (TG/DTA) [ 244 ].

Examples: TG/DTA is a common technique for the characterization of thermal properties of biogenic NPs. For instance, the thermal properties of Ag NPs produced by Daphne mucronate leaf extract were studied in the range between 0–1000 °C where the sample was heated at a rate of 10 °C/min. The researchers found that between 400–500 °C the NPs faced a dominant weight loss, while the weight loss below 400 °C and above 500 °C was negligible. The DTA curve showed an intense exothermic peak in the range between 400–500 °C, this indicates that the crystallization of NPs happens in this temperature interval. Some minor weight loss events were seen below 400 °C, this may be caused by the evaporation of water or the degradation of the organic components [ 249 ]. In another study, the thermal properties of Ag NPs produced by two different plants ( Stereospermum binhchauensis and Jasminum subtriplinerve ) were compared. The researchers found that the major weight loss happens between 220–430 °C, which is attributed to the decomposition of biomolecules from the NP surface [ 250 ]. This shows that Ag NPs produced by these plants have much higher content of biomolecules on their surface than Ag NPs produced by Daphne mucronate. TG/DTA showed that Stereospermum binhchauensis Ag NPs crystallize at 315 °C and Jasminum subtriplinerve Ag NPs at 345 °C, around 100 °C less than Daphne mucronate Ag NPs [ 250 ].

Transient hot wire method (THW)

This method is used for the determination of thermal conductivity based on increasing the temperature of a material by a thin hot wire as a function of time, where the heating wire is located directly in the test sample. The advantage of this method over other thermal conductivity measurement methods is the very short measuring time, this gives high accuracy of thermal conductivity due to the negligible values of convection in such short times [ 251 ]. In this method, the NPs are added to a solution (usually water or ethylene glycol) forming a colloidal dispersion called a nanofluid. Then, the thermal conductivity of the nanofluid is measured and compared to the thermal conductivity of the base fluid, giving a thermal conductivity ratio which is used to evaluate the thermal conductivity of different NPs.

Examples: The thermal conductivity ratios of three different concentrations (0.12, 0.18, and 0.24%) of biogenic SnO 2 NPs produced by Punica granatum seed extract were measured in ethylene glycol at 303 K. The researchers found a linear relationship between NPs concentration and the thermal conductivity. The thermal conductivity enhancement of nanofluid to base fluid was between 6 and 24% [ 252 ]. In another study, the thermal conductivity of Fe 2 O 3 NPs produced by Psidium guajava leaf extract was measured in water and in ethylene glycol. The researchers found that the thermal conductivity enhancement in ethylene glycol was better than in water, the thermal conductivity enhancement for 0.025% Fe 2 O 3 NPs in water was 30% while in ethylene glycol was 34%. Moreover, the linear relationship between NPs concentration and thermal conductivity ratio was found for Fe 2 O 3 NPs in both water and ethylene glycol [ 253 ].

Characterization of mechanical properties

Several methods can be used for the characterization of mechanical properties of NPs, such as tensile and compressive strengths, elasticity, viscoelasticity, hardness, and stiffness.

Tensometery

The machine used for this method is called a universal testing machine (UTM) or a tensometer. It is used to measure the elasticity (elastic modulus), tensile and compressive strengths (Young’s modulus) of materials. In this machine, the sample is placed between grips and an extensometer, where changes in gauge length are recorded as a function of load [ 254 ]. However, other mechanical changes in addition to the change in gauge length are also recorded in this machine, such as the elasticity.

Examples: The mechanical properties of different biogenic NP-containing composites can be measured by this machine. For example, the mechanical properties of orthodontic elastic ligatures containing Ag NPs produced by Heterotheca inuloides were studied by comparing the maximum strength, tension, and displacement of the composite with and without the biogenic NPs. The researchers found that maximum strength, tension, and displacement have improved after the addition of Ag NPs [ 255 ]. Interestingly, the addition of biogenic Ag NPs produced by Diospyros lotus fruit extract to starch and polyvinyl alcohol hydrogel membranes resulted in an adverse effect. The tensile strength and modulus of the hydrogel membranes containing 50 and 100 ppm Ag NPs were much lower than of the neat hydrogel membrane. The researchers attributed this adverse effect to the possibility that the addition of Ag NPs could have resulted in blocking the crosslinking between starch and polyvinyl alcohol, or to the possibility of the formation of breakage points in the polymer matrix due to NPs agglomeration [ 256 ].

Instrumented indentation testing

This method is used to characterize the hardness features of materials by using a well-defined hard indenter tip typically made of diamond. The indenter tip is used to make an indentation in the sample by placing incremental loads on the tip, after which the area of indentation in the sample is measured and used to calculate the hardness features [ 257 ]. Light microscopy, SEM, or ATM technique are usually used to visualize the indentation in the sample. The method is also called micro- or nano-indentation testing.

Examples: This method was used to characterize the mechanical properties of calcite NPs produced by Ophiocoma wendtii brittlestar. The arm plates of this brittlestar are covered by hundreds of nanoscale calcite lenses that focus light onto photoreceptor nerve bundles positioned beneath the brittlestar. The researchers used the nanoindentation method to compare Young’s modulus, hardness and fracture toughness of biogenic calcite with geocalcite. The results showed that the biogenic calcite lenses have higher hardness and fracture toughness compared to geocalcite (more than twofold) [ 258 ]. Bamboo is well known for its high silica content in comparison to other wood species. It produces SiO 2 NPs and deposits it in its epidermis in the form of silica cells. The mechanical properties of silica cells compared to other types of cells of Moso bamboo ( Phyllostachys pubescens ) were studied by instrumented indentation testing. The researchers found that the cell wall of silica cells display higher hardness and elastic recovery compared to fibre and epidermal cells, which is attributed to the presence of biogenic SiO 2 NPs in the silica cells [ 259 ].

Dynamic mechanical analysis (DMA)

This method is used to study the mechanical properties of materials by measuring the strain of a material after applying a stress. This method helps to obtain three different values: storage modulus, loss modulus, and loss tangent. These values are important to give an overview about the stiffness and viscoelasticity behavior of materials [ 260 ].

Examples: The DMA method was used to characterize the mechanical properties of polymethyl methacrylate denture base polymer filled with Ag NPs produced by Boesenbergia rotunda . In this study frequency sweep test was used to determine the viscoelastic behavior of this nanocomposite where the temperature was constant at 37 °C and the frequency was increasing from 0.5 to 100 Hz in tension mode. The researchers found a frequency dependence for storage modulus, loss modulus, and loss tangent for the nanocomposite with various Ag NPs loading concentrations. The frequency dependence of storage modulus, loss modulus, and loss tangent indicates the viscoelastic response of this polymer. However, the results showed that the storage modulus for the nanocomposite is much higher than the loss modulus over the range of frequencies, indicating the elastic dominance of the nanocomposite. Moreover, the researchers found that storage and loss moduli increase with increasing Ag NPs loading concentrations, which is due to the interaction between polymethyl methacrylate and Ag NPs [ 261 ].

In a different study, DMA was used to determine the thermomechanical properties of pol(S-co-BuA) polymer filled with cellulose nanocrystals produced by Posidonia oceanica . In this case, the behaviour of storge modulus and loss tangent were studied as a function of temperature for different cellulose nanocrystals loading concentrations. The results showed that the unloaded polymer behaves like an amorphous polymer, the storage modulus remains constant until the temperature reaches 25 °C then it starts to sharply decrease due to glass–rubber transition. A relaxation process was also evident for the unloader polymer, where the loss tangent reaches its maximum at 35 °C then it starts to fall. The addition of cellulose nanocrystals to the polymer positively enhanced both effects. The dramatic drop of storage modulus at 25 °C was less for the nanocomposite, where the drop for the polymer loaded with 15% cellulose nanocrystals was almost cancelled. Similar positive enhancement was found for loss tangent. These enhancements could be attributed to the mechanical coupling effect, in which the NPs connect and form a stiff continuous network linked through hydrogen bonding [ 262 ].

Applications of NPs

NPs, due to their above-mentioned unique or enhanced physicochemical properties, are used in a wide range of applications in different fields. In addition, several potential applications are in research and development. Here we present some examples of these applications.

Applications in medicine and pharma

Metallic and semiconductor NPs have huge potential for cancer diagnosis and therapy based on their enhanced light scattering and absorption properties due to LSPR effect. For instance, Au NPs efficiently absorb light and convert it into localized heat, which can be exploited for selective photothermal therapy of cancer (cancer cell death by heat generated in tumor tissue) [ 263 , 264 ]. In addition, the unique optical properties of Au NPs make them a great candidate for the photodynamic therapy of cancer (the use of a drug that is activated by light to kill cancer cells) [ 265 ]. Gd based NPs have also shown great abilities in tumor growth inhibition [ 266 ], metastasis inhibition [ 267 ], and tumor-specific magnetic resonance contrast enhancement [ 268 ]. Targeted drug delivery is also an important potential application of NPs. ZnO and Fe 3 O 4 NPs were efficiently used for targeted drug delivery and selective destruction of tumor cells [ 269 – 271 ].

Moreover, NPs have been successfully used in different medical applications such as cellular imaging [ 272 ], or in biosensors for DNA, carbohydrates, proteins, and heavy metal ions [ 273 , 274 ], determination of blood glucose levels [ 275 ], and for medical diagnostics to detect bacteria [ 276 ] and viruses [ 277 ]. For instance, Au NPs were conjugated with SARS-CoV-2 antigens to rapidly detect the presence of SARS-CoV-2 IgM/IgA antibodies in blood samples within 10–15 min [ 278 ], At the same time, due to their antimicrobial and antibacterial activities, NPs such as TiO 2 , ZnO, CuO, and BiVO 4 are being increasing used in various medical products such as catheters [ 279 , 280 ].

Applications in electronics

NPs, due to their novel electronic and optical properties, have a wide range of potential applications in imaging techniques and electronics. For instance, Gd-based NPs can improve the imaging quality and the contrast agent administration dose of magnetic resonance imaging (MRI). The use of Gd 2 O 3 NPs as a contrasting agent was found to be more efficient than the commonly used agent (Gd-DOTA) at the same concentration [ 281 ]. At the same time, GdPO 4 NPs were successfully used for tumor detection using MRI in 1/10 of the dose typically used with Gd-DTPA agent [ 282 ]. Interestingly, NPs also offer the ability to image and track a single molecule, which can reveal important information about cellular processes such as membrane protein organization and interaction with other proteins. For example, Eu 3+ -doped oxide NPs were used to track a single toxin receptor with a localization precision of 30 nm [ 283 ].

Regarding applications in batteries, an important component in lithium-ion batteries is the separators. Their main function is to prevent the physical contact of anode and cathode, and to provide channels for the transport of ions. The commonly used commercial material in battery separators, a polyolefin microporous membrane, suffers from poor electrolyte uptake and poor thermal stability [ 284 ]. Due to the aerogel structure of some NPs (such as ZnO NPs), they are an ideal choice for separator plates in batteries [ 284 ]. This makes the batteries store a significantly higher amount of energy compared to traditional batteries. For lithium-air batteries, using Pt-Au bimetallic NPs strongly enhances oxygen reduction and oxygen evolution reactions [ 285 ]. Moreover, batteries made of nanocrystalline Ni and metal hydrides last longer and require less charging [ 23 ]. In addition to battery applications, several NPs such as CdS and ZnSe are also used in light-emitting diodes (LED) of modern displays to get higher brightness and bigger screens [ 23 , 286 ]. Other NPs such as CdTe NPs are also used in liquid crystal displays (LCDs) [ 287 ]. The addition of a NP layer to LED and LCD enables them to generate more light using the same amount of energy and enhances their lifetime.

Applications in agriculture

NPs have potential to benefit the agriculture field by providing new solutions to current agricultural and environmental problems [ 288 ]. NPs are mainly used in two forms in agriculture, as nanofertilizers and nanopesticides. Chemical fertilizers have poor efficiency due to leaching and volatilization. In these cases, the farmers usually react by using excessive amounts of fertilizers, which increases crops productivity but has an environmental cost [ 288 ]. In contrast, nanofertilizers are compounds that are applied in smaller amounts than regular chemical fertilizers but yet have better efficiencies [ 289 ]. The difference in efficiency comes from the fact that they are able to release the nutrients just when and where they are required by the plants. In that way, they limit the conversion of excess amounts of fertilizer to gaseous forms or from leaking into the ground water [ 290 ]. Several NPs have been employed in the development of fertilizers, including SiO 2 , ZnO, CuO, Fe, and Mg NPs [ 291 – 293 ]. These nanofertilizers provide the plants with increased nitrogen fixation, improved seed germination, amelioration to drought stress, increased seed weight, and increased photosynthesis ability [ 291 – 293 ]. The large surface area and small size of these NPs are the main reasons for the better efficiencies of nanofertilizers over conventional fertilizers [ 294 ].

Several NPs have proven antimicrobial, insecticidal, and nematicidal activities, which makes them a promising alternative to chemical pesticides and a potentially cheaper alternative to biopesticides [ 294 ]. For instance, the photocatalytic activity of TiO 2 NPs gives them a potent antimicrobial activity against Xanthomonas perforans , the causing agent of tomato spot disease [ 295 ]. CuO NPs show insecticidal activity against Spodoptera littoralis , known as African cotton leafworm [ 296 ]. Ag NPs show nematicidal activity against Meloidogyne spp. , root-knot nematodes [ 297 ].

Applications in the food industry

NPs, despite toxological concerns, have impactful applications in several food industry-related process such as food production, preservation, and packaging. TiO 2 NPs are a major promising player in this industry. Their photocatalytic antimicrobial activity makes them an interesting material for food packaging [ 298 ]. In addition, they are also used in sensors to detect volatile organic compounds [ 299 ]. Ag NPs are also promising in food packaging due to their antimicrobial activity. They play an important role in reducing the risk of pathogens and extending food shelf-life [ 294 ]. The efficiency of doping Ag and ZnO NPs to degradable and non-degradable packaging materials for meat, bread, fruit, and dairy products was tested against several yeast, molds, aerobic, and anaerobic bacteria [ 300 ]. For instance, polyvinyl chloride doped with Ag NPs was evaluated for packing minced meet at refrigerator temperature (4 °C); the results showed that Ag NPs significantly helped to slow down bacterial growth, increasing the shelf-life of minced meet from 2 to 7 days [ 301 ].

Effects of NPs on biological systems

Although the use of NPs is exponentially growing, their possible toxicological and hazardous impacts to human health and environment cannot be ignored. NPs may get released to the environment during production stages, usage, recycling, or disposal. These NPs may persist in air, soil, water, or biological systems [ 302 ]. NPs can enter the human or animal body though the skin, orally, or via the respiratory tract, and afterwards move to other parts of the body. The exposure to NPs was found to activate proinflammatory cytokines and chemokines with recruitment of inflammatory cells, which impacts the immune system homeostasis and can lead to autoimmune, allergic, or neoplastic diseases [ 302 ]. Moreover, the exposure to ultrafine particles can cause pulmonary, cardiac, and central nervous system diseases [ 303 – 305 ]. Similarly, NPs can enter plants cells and cause harmful effects [ 306 ]. For instance, the exposure of ZnO and Al NPs was found to cause root growth inhibition in plants [ 307 , 308 ].

Nanoscience and nanotechnology are inherently transdisciplinary fields of science. With new bio-based approaches, there is a need for biologists to understand not only the basic principles of nanoscience, but also the technologies and methods traditionally employed to characterize nanomaterials. We hope that this review can help to inspire new collaborations across different scientific disciplines, by helping biologists to identify the best technologies—and partners—to characterize their nanomaterials. At the same time, we recommend to take potential biological risks of these new materials into careful consideration already during the planning phase of such experiments.

Acknowledgements

Abbreviations.

AFMAtomic force microscopy
BETBrunauer–Emmett–Teller
BJHBarrett–Joyner–Halenda
CVCyclic voltammetry
DLSDynamic light scattering
DLVODerjaguin–Landau–Verwey–Overbeek
DMADynamic mechanical analysis
DMTDerjaguin–Muller–Toporov
DRSUV–vis diffuse reflectance spectroscopy
DSCDifferential scanning calorimetry
DTADifferential thermal analysis
EDXEnergy-dispersive X-ray spectroscopy
EMElectron microscopy
EPRElectron paramagnetic resonance spectroscopy
ESRElectron spin resonance spectroscopy
FTIRFourier-transform infrared spectroscopy
HAADFHigh-angle annular dark-field imaging
ISOInternational Organization for Standardization
JKRJohnson–Kendall–Roberts
LCDLiquid crystal display
LEDLight-emitting diode
LSPRLocalized surface plasmon resonance
MFMMagnetic force microscopy
MRIMagnetic resonance imaging
NPsNanoparticles
NTANanoparticle tracking analysis
PLPhotoluminescence spectroscopy
r Critical radius
r Threshold radius for superparamagnetism
SAEDSelected area electron diffraction
SEMScanning electron microscopy
SERSSurface-enhanced Raman spectroscopy
SPRSurface plasmon resonance
SQUIDSuperconducting quantum interference device
STEMScanning transmission electron microscopy
STMScanning tunneling microscopy
TEMTransmission electron microscopy
TG/DTAThermogravimetry/differential thermal analysis
TGAThermogravimetric analysis
THWTransient hot wire
UTMUniversal testing machine
UVUltraviolet
UV–visUltraviolet–visible spectroscopy
VSMVibrating-sample magnetometry
XPSX-ray photoelectron spectroscopy
XRDX-ray diffraction analysis

Author contributions

NJ wrote the manuscript. DL edited the manuscript. Both the authors read and approved the final manuscript.

This work was supported by the Research Council of Norway, Grant 294605 (Center for Digital Life) to DL.

Availability of data and materials

Declarations.

The authors declare that they have no competing interests.

1 https://www.etymonline.com/word/nano .

2 [SOURCE: ISO/TS 80,004‑2:2015, 4.4].

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Encyclopedia Britannica

  • History & Society
  • Science & Tech
  • Biographies
  • Animals & Nature
  • Geography & Travel
  • Arts & Culture
  • Games & Quizzes
  • On This Day
  • One Good Fact
  • New Articles
  • Lifestyles & Social Issues
  • Philosophy & Religion
  • Politics, Law & Government
  • World History
  • Health & Medicine
  • Browse Biographies
  • Birds, Reptiles & Other Vertebrates
  • Bugs, Mollusks & Other Invertebrates
  • Environment
  • Fossils & Geologic Time
  • Entertainment & Pop Culture
  • Sports & Recreation
  • Visual Arts
  • Demystified
  • Image Galleries
  • Infographics
  • Top Questions
  • Britannica Kids
  • Saving Earth
  • Space Next 50
  • Student Center
  • Introduction

Properties of nanoparticles

Nanoparticle-based technologies.

  • Food packaging
  • Flame retardants
  • Batteries and supercapacitors
  • Nanoceramics
  • Light control
  • Nanoparticle applications in medicine
  • Manufacture of nanoparticles
  • Detection, characterization, and isolation
  • Nanoparticles in the environment
  • Health effects of nanoparticles

Image showing nanoparticles of an alloy of gold (yellow) and palladium (blue) on an acid-treated carbon support (gray). These particles were employed as catalysts for the formation of hydrogen peroxide from hydrogen (white) and oxygen (red).

  • Why does physics work in SI units?
  • Is mathematics a physical science?

Highway Night Traffic Portland, drive, driving, car, automobile.

nanoparticle

Our editors will review what you’ve submitted and determine whether to revise the article.

  • European Commission - Nanotechnologies
  • National Center for Biotechnology Information - PubMed Central - Nanoparticles and their Applications in Cell and Molecular Biology
  • Table Of Contents

Image showing nanoparticles of an alloy of gold (yellow) and palladium (blue) on an acid-treated carbon support (gray). These particles were employed as catalysts for the formation of hydrogen peroxide from hydrogen (white) and oxygen (red).

Recent News

nanoparticle , ultrafine unit with dimensions measured in nanometres (nm; 1 nm = 10 −9 metre). Nanoparticles exist in the natural world and are also created as a result of human activities. Because of their submicroscopic size, they have unique material characteristics, and manufactured nanoparticles may find practical applications in a variety of areas, including medicine , engineering , catalysis, and environmental remediation.

nanoparticle review nature

In 2008 the International Organization for Standardization (ISO) defined a nanoparticle as a discrete nano-object where all three Cartesian dimensions are less than 100 nm. The ISO standard similarly defined two-dimensional nano-objects (i.e., nanodiscs and nanoplates) and one-dimensional nano-objects (i.e., nanofibres and nanotubes). But in 2011 the Commission of the European Union endorsed a more-technical but wider-ranging definition:

a natural, incidental or manufactured material containing particles, in an unbound state or as an aggregate or as an agglomerate and where, for 50% or more of the particles in the number size distribution, one or more external dimensions is in the size range 1 nm–100 nm.

Under that definition a nano-object needs only one of its characteristic dimensions to be in the range 1–100 nm to be classed as a nanoparticle, even if its other dimensions are outside that range. (The lower limit of 1 nm is used because atomic bond lengths are reached at 0.1 nm.)

That size range—from 1 to 100 nm—overlaps considerably with that previously assigned to the field of colloid science—from 1 to 1,000 nm—which is sometimes alternatively called the mesoscale. Thus, it is not uncommon to find literature that refers to nanoparticles and colloidal particles in equal terms. The difference is essentially semantic for particles below 100 nm in size.

Nanoparticles can be classified into any of various types, according to their size, shape, and material properties. Some classifications distinguish between organic and inorganic nanoparticles; the first group includes dendrimers, liposomes, and polymeric nanoparticles, while the latter includes fullerenes , quantum dots, and gold nanoparticles. Other classifications divide nanoparticles according to whether they are carbon-based, ceramic, semiconducting, or polymeric. In addition, nanoparticles can be classified as hard (e.g., titania [ titanium dioxide ], silica [silica dioxide] particles, and fullerenes) or as soft (e.g., liposomes, vesicles, and nanodroplets). The way in which nanoparticles are classified typically depends on their application, such as in diagnosis or therapy versus basic research, or may be related to the way in which they were produced.

nanoparticle review nature

There are three major physical properties of nanoparticles, and all are interrelated: (1) they are highly mobile in the free state (e.g., in the absence of some other additional influence, a 10-nm-diameter nanosphere of silica has a sedimentation rate under gravity of 0.01 mm/day in water); (2) they have enormous specific surface areas (e.g., a standard teaspoon, or about 6 ml, of 10-nm-diameter silica nanospheres has more surface area than a dozen doubles-sized tennis courts; 20 percent of all the atoms in each nanosphere will be located at the surface); and (3) they may exhibit what are known as quantum effects. Thus, nanoparticles have a vast range of compositions , depending on the use or the product.

nanoparticle review nature

In general, nanoparticle-based technologies centre on opportunities for improving the efficiency , sustainability, and speed of already-existing processes. That is possible because, relative to the materials used traditionally for industrial processes (e.g., industrial catalysis ), nanoparticle-based technologies use less material, a large proportion of which is already in a more “reactive” state. Other opportunities for nanoparticle-based technologies include the use of nanoscale zero-valent iron (NZVI) particles as a field-deployable means of remediating organochlorine compounds , such as polychlorinated biphenyls (PCBs), in the environment . NZVI particles are able to permeate into rock layers in the ground and thus can neutralize the reactivity of organochlorines in deep aquifers . Other applications of nanoparticles are those that stem from manipulating or arranging matter at the nanoscale to provide better coatings, composites, or additives and those that exploit the particles’ quantum effects (e.g., quantum dots for imaging, nanowires for molecular electronics , and technologies for spintronics and molecular magnets).

Michigan Engineering News

A vertical semi-transparent beam passes through a three-dimensional, rectangular box that holds a blue liquid with gold blocks floating inside.

Morphable materials: Researchers coax nanoparticles to reconfigure themselves

It’s a step toward smart coatings that change color—or other properties—on the fly.

Derek Smith

Tobias Dwyer

Portrait of Tobias Dwyer

See full bio

Chemical Engineering Doctoral Student

Portrait of Tim Moore

Assistant Research Scientist of Chemical Engineering

Sharon Glotzer

Portrait of Sharon Glotzer

Anthony C. Lembke Department Chair of Chemical Engineering

A view into how nanoscale building blocks can rearrange into different organized structures on command is now possible with an approach that combines an electron microscope, a small sample holder with microscopic channels, and computer simulations, according to a new study by researchers at the University of Michigan and Indiana University.

The approach could eventually enable smart materials and coatings that can switch between different optical, mechanical and electronic properties.

“One of my favorite examples of this phenomenon in nature is in chameleons,” said Tobias Dwyer , U-M doctoral student in chemical engineering and co-first author of the study published in Nature Chemical Engineering. “Chameleons change color by altering the spacing between nanocrystals in their skin. The dream is to design a dynamic and multifunctional system that can be as good as some of the examples that we see in biology.”

The imaging technique lets researchers watch how nanoparticles react to changes in their environment in real time, offering an unprecedented window into their assembly behavior.

A vertical semi-transparent beam passes through a three-dimensional, rectangular box that holds a blue liquid with gold blocks floating inside.

In the study, the Indiana team first suspended nanoparticles, a class of materials smaller than the average bacteria cell, in tiny channels of liquid on a microfluidic flow cell. This type of device allowed the researchers to flush different kinds of fluid into the cell on the fly while they viewed the mixture under their electron microscope. The researchers learned that the instrument gave the nanoparticles—which normally are attracted to each other—just enough electrostatic repulsion to push them apart and allow them to assemble into ordered arrangements.

The nanoparticles, which are cubes made of gold, either perfectly aligned their faces in a tidy cluster or formed a more messy arrangement. The final arrangement of the material depended on the properties of the liquid the blocks were suspended in, and flushing new liquids into the flow cell caused the nanoblocks to switch between the two arrangements.

The experiment was a proof of concept for how to steer nanoparticles into desired structures. Nanoparticles are too small to manually manipulate, but the approach could help engineers learn to reconfigure other nanoparticles by changing their environment.

“You might have been able to move the particles into new liquids before, but you wouldn’t have been able to watch how they respond to their new environment in real-time,” said Xingchen Ye , IU associate professor of chemistry who developed the experimental technique and is the study’s lead corresponding author.

“We can use this tool to image many types of nanoscale objects, like chains of molecules, viruses, lipids and composite particles. Pharmaceutical companies could use this technique to learn how viruses interact with cells in different conditions, which could impact drug development.”

Video Description

Two side-by-side circles show a view of tiny squares clustered together in a messy arrangement, one in grayscale and another in a rainbow of colors. Their arrangement and colors change as different solvents are added to their environment When the solvent switches to a mixture of octane and butanol, the squares’ faces align more closely and the reds and yellows change to blue and green. The squares return to a messy arrangement with more red and yellow squares when they are put back in butanol. A scale next to the right shows how the squares’ color corresponds to how they have rotated: 0 and 90 degrees in blue, 22 degrees in aquamarine, around 40 degrees in yellow, and around 60 degrees in red.

An electron microscope isn’t necessary to activate the particles in practical morphable materials, the researchers said. Changes in light and pH could also serve that purpose.

But to extend the technique to different kinds of nanoparticles, the researchers will need to know how to change their liquids and microscope settings to arrange the particles. Computer simulations run by the U-M team open the door to that future work by identifying the forces that caused the particles to interact and assemble.

“We think we now have a good enough understanding of all the physics at play to predict what would happen if we use particles of a different shape or material,” said Tim Moore , U-M assistant research scientist of chemical engineering and co-first author of the study. He designed the computer simulations together with Dwyer and Sharon Glotzer , the Anthony C. Lembke Department Chair of Chemical Engineering at U-M and a corresponding author of the study.

“The combination of experiments and simulations is exciting because we now have a platform to design, predict, make and observe in real time new, morphable materials together with our IU partners,” said Glotzer, who is also the John Werner Cahn Distinguished University Professor and Stuart W. Churchill Collegiate Professor of Chemical Engineering.

The research is funded by the National Science Foundation.

ALTMETRIC ATTENTION SCORE

Study: engineering and direct imaging of nanocube self-assembly pathways.

Written in collaboration with Jaleesa Elliott, Indiana University Research Communications

Media Contact

News & Feature Writer

(734) 647-7000

[email protected]

Related Stories

Nanoscale engineering brings light-twisting materials to more extreme settings.

New manufacturing method builds tougher materials that were previously considered useless for twisting light into more robust optical devices.

Targeting multiple COVID variants through the twist in the spike protein

Particles that gum up the keys that the virus uses to enter cells could one day be an effective COVID treatment whenever vaccines and other treatments fall short.

Related Topics

Royal Society of Chemistry

Method development and analysis of nanoparticle size fractions from tire-wear emissions †

ORCID logo

First published on 20th August 2024

Herein, we examine the generation of nanoparticles from tire and road interactions, with a focus on two key aspects: replicating real-world conditions in a controlled environment for particle generation and analysing the collected particles through both online and offline techniques. In order to generate realistic wear patterns, third body particles were used in a standardized laboratory tire testing facility across dynamic and static speeds and load profiles. The findings indicated that milled stone dust as a third body particle significantly disrupted the nanoparticle size range, complicating the differentiation between tire-based and third-body-based nanoparticles. However, using sand as a third body particle, the interference showed comparatively lower background noise within the nanoparticle region. Here, steady-state cycles were employed to discern the relationships between force events and nanoparticle generation, which were compared to analyses conducted over an entire dynamic drive cycle. The steady-state cycles revealed that high lateral forces (>2 kN) yielded the highest nanoparticle concentrations, surpassing background levels by over two orders of magnitude. Meanwhile, the drive cycle trials indicated that approximately 70% of the emitted nanoparticles throughout the entire drive cycle were semi-volatile emissions, likely originating from vaporization events. ICP-MS results confirmed the presence of tire-related elements in the nanoparticle region, but definitive attribution to the tire or road surface remains a challenge for the field. This study underscores the complexities inherent in generating, collecting, and assessing submicron tire wear particles, laying the groundwork for addressing uncertainties and refining non-exhaust tire emission methodologies.

A typical problem in understanding emissions from tire wear particles generated under realistic driving conditions, in conjunction with road wear particles, is recreating real-world driving conditions in laboratory settings. Here, the research focuses on uncovering nanoparticles generated under real-world driving conditions while using third body particles. Key findings indicate that nanoparticles are predominantly semi-volatile rather than solid, as concluded through online and offline analysis, including, for the first time with non-exhaust tire emissions, a catalytic stripper to provide information on the solid component of non-exhaust emissions. Generalizing this requires considering the composition of rubber for health-related impacts. Addressing this is crucial for determining the contribution to urban emissions, especially with the increasing electrification of passenger fleets.

Introduction

Previous studies have shown that standardized laboratory wear testing must include “third body particles” to enable test results that mimic known real-world wear. By incorporating third body particles like sand, chalk, and stone dust, macroscopic wear and large particle emissions correspond to real-world driving conditions more accurately, as these materials are commonly encountered on roads and play critical roles in how tires emit particles. 3–5 However, careful selection of third body materials is vital, as certain substances may hinder the accurate characterization of tire emissions depending on the size fraction of interest.

In previous work, particulate matter (PM) has been measured using cyclones for size fractionation at 10 μm (PM 10 ) and 2.5 μm (PM 2.5 ), or higher size resolution instrumentation has been used such as an Electrical Low-Pressure Impactor (ELPI). 6 The size fractions of release have differing sensitivities. Increasing the lateral loads at a constant driving speed decreased the PM 2.5 to PM 10 ratio exponentially, where PM 10 emissions were found to be 3.8 times more sensitive to load than PM 2.5 . 7 However, nanoparticle production from tires, specifically those <100 nm, is more sensitive to higher slip angles and longitudinal forces. 8

Collection mechanisms have ranged from sampling directly behind the tire 8–10 or downstream with the help of an extraction system that pulls the particles to the collection locations. 6,7,11 The collection mechanisms either deposit particles on filters for offline analysis or assess the incoming particles in real time for online analysis. The tire collections and analyses have employed methods and instrumentation that often do not include ultrafine particles (<300 nm). 6 This means that ultrafine particles from tire and road wear particles (TRWPs) continue to be less understood. In part, studies that are done in an open system, or those that do not extract particles from directly behind the tire, are at a much higher risk of ultrafine particle loss. 12 Also, because humidity can influence the size of the particles detected, specifically ultrafine particles, the distance from particle generation to particle collection should be minimized to reduce the impact of humidity. 13

Overall particle generation sensitivities have been correlated to the load, tire speed, overall distance travelled, slip speed, tire tread loss (mg), wear rate (mg km −1 ), and PM 2.5 to PM 10 ratios. 6,7,14 In addition, the particle distributions have been shown to depend on the severity of the drive cycle. Mathissen et. al. have shown that harsh driving conditions have bimodal size distributions, whereas other driving modes tend to have unimodal distributions. 10 The existing literature on tire and road wear nanoparticles has established a foundation for the research presented herein, where a notable gap is the absence of recreating representative driving conditions within the testing environment.

Characterising the chemical composition requires significant instrumentation resources for on-line analysis and careful sample collection and storage for off-line analysis. The use of a catalytic stripper (CS) 15 allows on-line particle distinction to be made between solid and semi-volatile particles when used in conjunction with appropriate particle measurement, e.g. ELPI. By comparing data obtained with and without the CS, studies can discern details about the evaporated and solid fraction of micrometre to nanometre sized particles. While prior research has utilized this technique to monitor exhaust emissions 16,17 and urban pollution, 18 its application to submicron emissions from tire operations has not yet been shown.

Our present work provides quantified measurements of nanoparticle emissions from standardized tire test conditions, building on previous studies. We incorporate third body particles to emulate the critical interaction between the tire and road surface that exists in the real world. Here, trials of steady-state cycles and previously reported drive cycles are used to assess particle size distributions, specifically focusing on the nanoparticle size range, for tire and road wear particles while using third body particles within a laboratory setting to represent real-world driving conditions. The difference between mass and particle number (PN) distribution is explored in relation to nanoparticle tire and road wear emissions. Further, we develop new testing structures that incorporate third body particles, which are compared to previously reported literature based on force-dependent emissions. Finally, the use of a catalytic stripper provides new insights into non-exhaust emissions differentiating between solid and semi-volatile size distributions, where comparisons can be made to offline microscopy and mass spectrometry analysis.

Materials and methods

Testing the rig and tire.

The same summer tire was tested throughout the study, with AC 11 D S asphalt. The tires were packed and stored in tire bags in a protected space when they were not being tested. These tires were manufactured in 2022.

The sampling location and extraction system were tested at the onset of this study, where various locations and particle losses were examined (see Fig. S3 and S4 † ). The final configuration used in the study is depicted in Fig. 1 , where Fig. 1a shows where the third body particles are introduced into the system ( Fig. 1a-1 ) and where the extraction system ( Fig. 1a-2 ) attaches to the scoop that sits behind the tire in Fig. 1a-3 . The tire used was a new summer tire and was not equipped with any studs or spikes and had a symmetrical tread pattern, and thus negative and positive slip angles should result in comparable tire emissions. Two drive cycles are detailed here, steady state cycles and a portion of a drive cycle used by the Tire Industry Project, both reported in previous studies. 8,19

Picture of the (a) inner drum highlighting where the third body particles are introduced, where the extraction is connected to the (b) tire and where the particles are collected from ref. in relation to the tire. (c) Post-processing method for determining the background or baseline and particle number concentration. The blue boxes represent steady-state operation without the tire drum to assess background particles from third body addition, the rig itself, or ambient nanoparticles. The red line denotes the background concentration in relation to the rest of the drive cycle.

The ELPI has 14 stages that bin particles by size, where they are counted as they deposit onto their respective stage based on the aerodynamic particle diameter with an approximate logarithmic spacing between 10 μm and 6 nm (see Table S1, † where green denotes the nanoparticle stages). 22 The ELPI data provide a particle number based on particles that impact stages as they are brought into the instrument. The deposition of the particle is dependent on the equivalent aerodynamic diameter, and the default size interpretation assumes that particles are spherical with a density close to 1 g cm −3 . 23 The micron-sized particles sampled here are likely to have non-spherical morphologies, as shown in previous literature reports, and the morphology of the submicron fraction is unknown. The density used throughout this study was 1.1 g cm −3 , which is likely to be less than the true density of the particles collected throughout this work. Because the composition of the particles is largely unknown, the density used could underpredict the mass distribution, but does not influence the particle number concentrations reported.

High flow impactor

Sem with edx, catalytic stripper.

There are corrections for particle loss within the CS where the literature reports penetration curves for solid particles. 25,26 The influences of diffusion and thermophoretic losses within the CS for this dataset are discussion within the results.

Background particles

Testing structure.

The test structure shown in Table 1 was determined to reduce third body intake into the instrumentation, provide real-world conditions ( i.e. retaining third body particles) throughout the run cycle, and account for background nanoparticle concentrations within the rig and from the third body particles. The sand used here was Arizona find dust. The exact composition of third body particles in real-world settings is not homogenous and is required for realistic friction combinations. The sand is thus introduced at a lower speed at the beginning of the test cycle as there is less turbulence in the drum.

Time elapsed (min) Cycle event
0 Add 10 g of sand mixture
0–5 Run the rig with no tire contact
5 HEPA filters and extraction turned on
5–8 Run the rig at steady-state (50 kilometres per hour) for background concentration
8–28 Drive cycle or steady-state cycles
28–31 Run the rig at steady-state (50 kilometres per hour) for background comparison

A graphical representation of lateral force and acceleration for the drive cycle is shown in ESI Fig. S6, † where there is a higher frequency of left cornering events (right half of the graph) than right cornering events and more accelerating than decelerating (top vs. bottom, respectively) events. However, all four quadrants are expressed throughout the drive cycle and are representative of real-world driving conditions. This drive cycle focuses on city driving, which comprises 70% of driving on a global scale. 27 Therefore, the TRWP nanoparticles that are reported here are representative of real-world city-driving conditions.

Results and discussion

Comparison of third body materials.

Particle size distribution by concentration (colour bar) shown for (a) milled stone dust and (b) sand at a constant tire speed of 50 kilometres per hour.

The sand third body particles ( Fig. 2b ) exhibited lower concentrations (PN per stage <500 PN per cm 3 ) of background particles compared to MSD, reducing instrument noise throughout the drive cycle. The sand interference remained significant (>500 PN per cm 3 ) for the first two stages of the ELPI ( d p ≤ 16 nm) but was markedly improved compared to MSD, which significantly interfered with eight ELPI stages ( d p ≤ 380 nm). Additionally, the fine texture of MSD tended to obstruct the inlet of the ELPI. Thus, sand was validated and used as the third body material for the experiments conducted herein. There were additional measures taken to reduce interference from large sand particles within the ELPI, such as only connecting the ELPI to the extraction system when the sand had reached a uniform concentration within the rig, as summarised in Table 1 .

For nanoparticle TRWP emission studies, it is concluded that sand maintains the tire's integrity, while representing real-world driving conditions with reduced interference compared to milled stone dust.

Comparison of PN and PM

When considering PM emissions throughout the TRWP cycle from all particles (solid and semi-volatile) 95% of the total mass was represented in the micron-sized ELPI stages. The mass distribution shifts when the solid component is considered independently (with the CS), and here the five largest ELPI stages account for 95% of the mass collected. The broadening of mass distribution could indicate that semi-volatile particles have condensed onto solid, micron-sized particles, and when evaporated, there is a small amount of mass lost in these size ranges. The contribution from nanoparticles to the mass concentration is minor, and thus using mass as a metric to analyse nanoparticles generated by tire-road interactions does not provide suitable resolution above the background.

Considering PN, 95% of the TRWPs are <250 nm, highlighting the importance of focusing on a number-based metric for assessing nanoparticle TRWPs. The solid PN distribution (CS) has a broadening of the relative concentration of particles, indicating that there could be a semi-volatile component to these particles as well; however, the 95% distribution remains < 250 nm. Table S2 † also shows that micron particles do not contribute a significant amount of total PN.

Drive cycle emissions

Throughout the drive cycle, there are specific events that generate particles during (a) normal and severe driving modes and with and without the catalytic stripper. Comparing the driving mode with and without the catalytic stripper is shown in (b) for semi-volatile (SV) particles.

To compare the response to more severe driving behaviour, the lateral force was increased and the cycle is more representative of severe cornering. Here, only one force is increased for the severe mode in order to reduce the effects of multi-variable changes. TRWP generation is shown to increase with increased lateral loads compared to the normal driving mode. In addition, by subtracting the total particles from the total solid particles, the semi-volatile fraction of emitted particles can be calculated, which is shown in Fig. 3b for the nanoparticle size fraction (SV 1 ) and all size fractions collected (SV 10 ). The difference between SV 1 and SV 10 is most noticeable during high emitting events.

Fig. 4 , which is background corrected, shows the total particles generated in particle number concentration (a) and particle mass (b) by size compared to the solid particles generated throughout the drive cycle, in Fig. 4c and d , respectively. The solid fraction of the particles only comprises a small fraction of the total particles emitted, as shown by comparing Fig. 4b to a. Data below the white dashed lines within Fig. 4a and b highlight the size bins where 95% of the particle number concentration can be found, which is in size bins <250 nm, whereas 95% of PM can be found >1 μm, as shown with the black dashed line in Fig. 4c and d, indicating the size bins where 95% of particle mass was collected throughout the drive cycle.

The size distribution is shown for the entire drive cycle driven displayed by particle number concentration for data (a) without the CS (total particle number) and (b) with the CS (solid particle number) in comparison to the mass distribution by size bins for data (c) without the CS data (total particle mass) and (d) with the CS (solid particle mass). Data below the dashed line (a and b) represent the size bins where 95% of the particle number concentration is collected and data in size bins above the black dashed line (c and d) comprise 95% of the mass concentration. These data are background corrected.

The particle distribution shown in Fig. 4b has been background corrected and thus could represent particle collection noise due to third body particles, as they would not be removed by the CS or they could be solid tire/road particles that have chemical compositions that are stable above 350 °C. Comparatively, Fig. 4a shows high particle concentrations (>2000 PN per cm 3 per size bin in the nano-range) that were removed by the CS ( Fig. 4b <500 PN per cm 3 per bin) and are not present in the CS-based data. Here, over the course of the drive cycle, more than 70% of the particles (above background) are semi-volatile and are evaporated when subjected to the CS. The difference in measured TRWPs between solid particles ( Fig. 4b ) and total particles ( Fig. 4a ) is most pronounced during high concentration events, exemplified during 200, 700, 800 and 1200 s of the drive cycle. Further speciation is needed to quantify and characterise the chemical composition of the nanoparticle size bins; however, this is complicated by the amount of mass required to perform these types of analyses. The particle distribution shown for both PN and PM is reproducible for all valid test results (Table S2 † ), and corroborates previous work at KIT that did not use third body particles where >95% of PN is <300 nm. 8

The mass distribution for the drive cycle is shown for total particles ( Fig. 4c ) and solid particles ( Fig. 4d ), where it is apparent that the majority of mass in both distributions is micron sized (>1 μm). Comparing Fig. 4a and c , the total particle size distribution shows that both a large number of particles are generated in the nano-size bins and a high mass in the micron-sized bins. However, comparing the solid particle number ( Fig. 4d ) to solid particle mass ( Fig. 4b ) indicates that there are few particles (indistinguishable by number) that contribute to high solid mass concentrations during the drive cycle. It is not known whether these large particles are third body silica or TRWP emissions.

There is continuity between drive cycles and the fingerprint created. The majority of particles are semi-volatile throughout both drive cycles and are primarily nanoparticles, except for specific high-force events.

Steady state cycle emissions

The steady-state force (right axis, orange) is shown with particle concentration (left, blue) for (a) PM and (b) PN measurements for submicron particles (PN solid line) and up to 2.5 microns (PM dotted line). The PN and PN lines are indistinguishable as they overlap.

Fig. 5 demonstrates that PM 1 and PM 2.5 have over an order of magnitude difference in PM generated during force events, whereas there is no distinguishable difference between PN 2.5 and PN 1 indicating that nearly all particles generated during these force events are within the nanoparticle range.

To investigate the generation events leading to TRWP nanoparticle emissions, particle concentrations within various size ranges are examined versus applied force in Fig. 6 . Two trials of SSCs are segregated by particle sizes of 6–260 nm (PN 0.3 ), 260 nm–0.98 μm (PN 0.3–1 ) and 0.98 μm–10 μm (PN 1–10 ), as well as by the absolute force exerted during the SSC for 2.5 kN (blue), 2 kN (purple) and 1 kN (green). The particle size distributions for these forces are explicitly shown in Fig. S9. † Fig. 6 shows the total particles generated ((a), without the CS) and for the solid fraction of the generated particles ((b), with the CS). The larger fractions (PN1 and PN10) have statistically insignificant increases in the mean and interquartile spread between forces. As the force increases, the total concentration increases, but specifically in the smallest size fraction. Fig. 6a shows that at 2.5 kN, the mean PN 0.3 concentration increases by 195% compared to concentrations at 2 kN and 1 kN forces. It is also clear that the interquartile range broadens as the force increases, meaning that the TRWPs generated during high force events are more variable than those generated during lower force events, which could be due to the “memory effects” of the time–temperature profile of the tire during a drive cycle. Memory effects occur when a specific event within a drive cycle influences a later emission event, such as a high friction or force event that could result in a different subsequent emission than a low friction or force event.

Box and whisker plot for steady-state cycle data shown for repeat cycles for PN (a) without the CS (representative of all particles) and (b) with the CS (only the solid, non-evaporative particles). The data are grouped for particle sizes 0.006–0.26 μm (PN ), 0.26–1 μm (PN ), and 1–10 μm (PN ). The analysis is shown for 2.5 kN (blue), 2 kN (purple), and 1 kN (green) forces.

Fig. 6b shows the solid fraction generated by SSC force on the same scale as Fig. 6a . All size ranges have consistent low particle concentrations (<170 PN per cm 3 ), with the exception of PN 0.3 when subjected to a 2.5 kN force, where we see an increase in outlier concentrations. This collective analysis shows that SSCs provide insights into threshold forces for nanoparticle generation. The current tire and speed configuration demonstrate that particles in size bins 6–260 nm (PN 0.3 ) are present at all forces, but the concentration increases when forces are above 2 kN, where the majority of nanoparticles are semi-volatile. This method provides a pathway for broader investigations of different tires and speed-load conditions for our continued studies of nanoparticle TRWP generating events.

SSCs give nuanced insight into when nanoparticles are generated, expanding on full drive cycle analyses. Here, the SSCs conclude that at lower force events, semi-volatile nanoparticles are less likely to be generated, whereas forces >2 kN generate semi-volatile nanoparticles.

Chemical assessment

Fig. 7 shows the results of the Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis on submicron particles for two sampling days. On each day, eight TRWP cycles were deposited onto each substrate with the goal of increasing the deposited mass on each substrate for ICP-MS digestion. To ensure sufficient mass for ICP-MS digestion, particles from two impactor stages were combined, the <250 nm size bins and the 250 nm–1 μm size bins. The sample preparation and digestion method followed a previously published methodology, and due to the mass required for offline analyses, there was not enough material to compare catalytic stripper based samples. 24

ICP-MS results for two separate days, denoted with blue and red, including only submicron TRWPs.

Moreover, the analysis revealed the presence of zinc (Zn) within the emitted submicron particles. Previous research has established Zn as a constituent of tire rubber; 24 however, this work cannot definitively say that Zn is solely a result of tire compound emissions. It is worth noting that sand could not be digested for ICP-MS analysis due to the unavailability of hydrofluoric acid digestion capabilities at our facility. Future work may include comparing the composition of the emitted particles to the digested sand third body particles, as well as the road surface, further identifying and differentiating elemental markers capable of distinguishing between tire rubber and road material.

SEM images for the chemical composition of (a) a 70 nm stage particle (blue) and background (grey), (b) a 1 μm stage particle (purple) and (c) a >10 μm stage particle highlighting the (d) tire (maroon) and sand (red) components. The EDX spectrum is shown (e) with present elements noted.

Conclusions

Firstly, it was observed that milled stone dust significantly interfered with nanoparticle size bins, as evident from the high concentrations within the ELPI. The interference made the differentiation of submicron emissions that were tire-based vs. third-body-based difficult to quantify, whereas the sand interference was comparatively lower, allowing for reduced background noise during particle generation studies. The use of previously used drive cycles provided insights into tire emissions under simulated real-world driving conditions, although the high rate of force changes posed challenges in attributing specific force events to particle generation events. Therefore, steady-state cycles were used for a more nuanced understanding of generation events, revealing that high lateral forces (>2 kN) generated the highest submicron concentrations, over 2 orders of magnitude higher than background submicron concentrations.

The online and offline methods together supported the conclusion that the majority of nanoparticles, ∼70% of emitted submicron particles over the entire drive cycle, were semi-volatile emissions. This remains true when considering any diffusional or thermophoretic losses within the catalytic stripper. The exact chemical speciation of the emitted particles could not be concluded, but it is likely that these particles originate from vaporization events throughout the drive cycle. SEM results indicated the presence of sand particles in larger sizes but there was an absence of SiO in sub-100 nm particles. ICP-MS of submicron impactor substrates confirmed the presence of tire-related elements in the generated nanoparticles. However, definitive attribution to the tire or road surface was challenging and more work is needed in this area. With the conclusions from the SEM with EDX spectra, this work demonstrates a viable way to generate TRWP nanoparticles, which limits the interference of vital third body particles within the nanoparticle size range, while providing a new mechanism of sampling non-exhaust emissions with a catalytic stripper.

This study highlights the complexities involved in generating, collecting and assessing submicron tire wear particles. The generation method created here can be used. This work paves the way for future investigations to address remaining uncertainties and refine emission estimation methodologies.

Data availability

Conflicts of interest, acknowledgements.

  • D. Hesse, T. Feißel, M. Kunze, E. Bachmann, T. Bachmann and S. Gramstat, Comparison of Methods for Sampling Particulate Emissions from Tires under Different Test Environments, Atmosphere , 2022, 13 (8), 1262  CrossRef   CAS .
  • T. Grigoratos and G. Martini, Non-exhaust Traffic Related Emissions. Brake and Tyre Wear PM , 2014 [cited 2022 Nov 29], available from: https://core.ac.uk/download/pdf/38628016.pdf  Search PubMed .
  • J. A. Carrero, G. Arana and J. M. Madariaga, Chapter 6 Use of Raman spectroscopy and scanning electron microscopy for the detection and analysis of road transport pollution, In: Spectroscopic Properties of Inorganic and Organometallic Compounds , The Royal Society of Chemistry; 2014  Search PubMed .
  • N. Fillot, I. Iordanoff and Y. Berthier, Wear modeling and the third body concept, Wear , 2007, 262 (7–8), 949–957  CrossRef   CAS .
  • Transportation Research Board and Fahrwerk, Reifen, Fahrbahn im Spannungsfeld von Sicherheit und Umwelt , VDI-FVT, 2022  Search PubMed .
  • I. Park, H. Kim and S. Lee, Characteristics of tire wear particles generated in a laboratory simulation of tire/road contact conditions, J. Aerosol Sci. , 2018, 124 , 30–40  CrossRef   CAS .
  • G. Kim and S. Lee, Characteristics of Tire Wear Particles Generated by a Tire Simulator under Various Driving Conditions, 2018 [cited 2022 Nov 8], available from: https://pubs.acs.org/sharingguidelines.
  • M. J. Foitzik, H. J. Unrau, F. Gauterin, J. Dörnhöfer and T. Koch, Investigation of ultra fine particulate matter emission of rubber tires, Wear , 2018, 394–395 , 87–95  CrossRef   CAS .
  • X. dong Chang, H. bo Huang, R. nan Jiao and J. peng Liu, Experimental investigation on the characteristics of tire wear particles under different non-vehicle operating parameters, Tribol. Int. , 2020, 150 , 106354  CrossRef .
  • M. Mathissen, V. Scheer, R. Vogt and T. Benter, Investigation on the potential generation of ultrafine particles from the tire-road interface, Atmos. Environ. , 2011, 45 (34), 6172–6179  CrossRef   CAS .
  • C. A. Alves, A. M. P. Vicente, A. I. Calvo, D. Baumgardner, F. Amato and X. Querol, et al. , Physical and chemical properties of non-exhaust particles generated from wear between pavements and tyres, Atmos. Environ. , 2020, 224 , 117252  CrossRef   CAS .
  • T. Feißel, F. Büchner, M. Kunze, J. Rost, V. Ivanov and K. Augsburg, et al. , Methodology for Virtual Prediction of Vehicle-Related Particle Emissions and Their Influence on Ambient PM10 in an Urban Environment, Atmosphere , 2022, 13 , 1924  CrossRef . Available from: https://www.mdpi.com/2073-4433/13/11/1924/htm.
  • J. Kwak, S. Lee and S. Lee, On-road and laboratory investigations on non-exhaust ultrafine particles from the interaction between the tire and road pavement under braking conditions, Atmos. Environ. , 2014, 97 , 195–205  CrossRef   CAS .
  • K. M. Unice, M. P. Weeber, M. M. Abramson, R. C. D. Reid, J. A. G. van Gils and A. A. Markus, et al. , Characterizing export of land-based microplastics to the estuary – Part I: Application of integrated geospatial microplastic transport models to assess tire and road wear particles in the Seine watershed, Sci. Total Environ. , 2019, 646 , 1639–1649  CrossRef   CAS   PubMed .
  • Catalytic Instruments, Applications for the Catalytic Stripper . 2020  Search PubMed .
  • J. Swanson and D. Kittelson, Evaluation of thermal denuder and catalytic stripper methods for solid particle measurements, J. Aerosol Sci. , 2010, 41 , 1113–1122  CrossRef   CAS . available from: www.elsevier.com/locate/jaerosci.
  • I. S. Abdul-Khalek and D. B. Kittelson, Real Time Measurement of Volatile and Solid Exhaust Particles Using a Catalytic Stripper, J. Engines , 1995, 104 , 462–478  Search PubMed . Available from: https://www.jstor.org/stable/44633232.
  • M. J. Haugen, A. Singh, D. Bousiotis, F. D. Pope, A. M. Boies and M. J. Haugen, et al. , Differentiating Semi-Volatile and Solid Particle Events Using Low-Cost Lung-Deposited Surface Area and Black Carbon Sensors, Atmosphere , 2022, 13 , 747  CrossRef   CAS . Available from: https://www.mdpi.com/2073-4433/13/5/747/htm.
  • M. Kovochich, M. Liong, J. A. Parker, S. C. Oh, J. P. Lee and L. Xi, et al. , Chemical mapping of tire and road wear particles for single particle analysis, Sci. Total Environ. , 2021, 25 , 757  Search PubMed .
  • J. F. P. Cornette, J. Blondeau and S. Bram, Influence of the dynamic behaviour of impactor surfaces on particulate matter emission measurements with electrical low pressure impactors, Powder Technol. , 2023, 419 , 118333  CrossRef   CAS .
  • S. Saari, A. Arffman, J. Harra, T. Rönkkö and J. Keskinen, Performance evaluation of the HR-ELPI + inversion, Aerosol Sci. Technol. , 2018, 52 (9), 1037–1047  CrossRef   CAS .
  • Dekati, Dekati ELPI+ User Manual Ver 1.6 , 2021  Search PubMed .
  • U. Pujala, V. Subramanian, S. Anand and B. Venkatraman, Effect of morphological properties on the particle size distribution measurements and modelling of porous and nonspherical aerosol behaviour, Prog. Nucl. Energy , 2023, 163  Search PubMed .
  • D. P. O. Loughlin, M. J. Haugen, J. Day, A. S. Brown and E. C. Braysher, Multi-element Analysis of Tyre Rubber for Metal Tracers Multi-element analysis of tyre rubber for metal tracers, Environ. Int. , 2023, 178 , 108047  CrossRef   PubMed .
  • Catalytic Instruments, Note 00090 - Losses in the Catalytic Stripper, [cited 2024 Jun 18], available from: https://catalytic-instruments.com/?product_cat=catalytic-stripper.
  • M. Woo, G. Giannopoulos, M. M. Rahman, J. Swanson, M. E. J. Stettler and A. M. Boies, Multiscale numerical modeling of solid particle penetration and hydrocarbons removal in a catalytic stripper, Aerosol. Sci. Technol. , 2021, 55 (9), 987–1000  CrossRef   CAS .
  • T. Grigoratos, M. Giorgio and S. Heinz, Analysis of WLTP typical driving conditions that affect non-exhaust particle emissions [Internet], 2016, available from: https://ec.europa.eu/jrc.
  • S. Schläfle, H. Unrau and F. Gauterin, Influence of Load Condition, Tire Type, and Ambient Temperature on the Emission of Tire–Road Particulate Matter, Atmosphere , 2023, 14 (7), 1095  CrossRef .
Electronic supplementary information (ESI) available. See DOI:

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • View all journals
  • Explore content
  • About the journal
  • Publish with us
  • Sign up for alerts

Nanoparticles articles within Nature

Outlook | 11 July 2024

A light-touch approach to intracellular delivery

Getting molecules into cells using viral vectors or electroporation is expensive and laborious. The winner of the Spinoff Prize 2024 is showing that laser-heated nanoparticles could be an alternative solution.

  • Tim Vernimmen

News & Views | 17 April 2024

Nanoparticle fix opens up tricky technique to forensic applications

A technique called surface-enhanced Raman spectroscopy can detect tiny quantities of compounds in solution, but has been difficult to use for quantitative analysis. A digital approach involving nanoparticles suggests a way forward.

  • Peter J. Vikesland

News | 06 March 2024

Landmark study links microplastics to serious health problems

People who had tiny plastic particles lodged in a key blood vessel were more likely to experience heart attack, stroke or death during a three-year study.

Article 21 February 2024 | Open Access

Directive giant upconversion by supercritical bound states in the continuum

An experimental design consisting of a photonic-crystal nanoslab covered with upconversion nanoparticles demonstrates the phenomenon of supercritical coupling, resulting in giant enhancement of upconversion by photonic bound states in the continuum.

  • Chiara Schiattarella
  • , Silvia Romano
  •  &  Gianluigi Zito

Research Briefing | 20 December 2023

Atomic electron tomography reveals chemical order in medium- and high-entropy alloys

Medium- and high-entropy alloys are hugely promising materials in metallurgy and catalysis, but their atomic-scale structure — and how that relates to their properties — is not well understood. A powerful method is beginning to reveal their secrets, with hopes for engineering better materials in the future.

Article | 20 December 2023

Three-dimensional atomic structure and local chemical order of medium- and high-entropy nanoalloys

Atomic electron tomography is used to determine the 3D atomic positions and chemical species of medium- and high-entropy alloy nanoparticles and quantitatively characterize the local lattice distortion, strain tensor, twin boundaries, dislocation cores and chemical short-range order.

  • Saman Moniri
  •  &  Jianwei Miao

Research Briefing | 21 November 2023

Divide and conquer: exploiting entropy to grow nanoscale barrier materials

The full promise of materials structured at the nanoscale can be realized only if they can be manufactured more efficiently and at the sizes required for device integration. An innovative method takes advantage of thermodynamic and kinetic effects to control the growth of stacked 2D nanosheets that can be used for practical applications from the nanoscale to the macroscale.

Research Briefing | 14 June 2023

Nanoparticles containing diverse elements made using liquid metal

The synthesis of high-entropy alloy nanoparticles (HEA-NPs) — small particles each containing multiple principal metal elements — typically requires extreme conditions to ensure adequate mixing of constituents. Innovative experiments show that the liquid metal can act as a mixing reservoir to facilitate the synthesis of a diverse range of such nanoparticles in mild conditions.

Article | 14 June 2023

Liquid metal for high-entropy alloy nanoparticles synthesis

We discovered that liquid metal endowing negative mixing enthalpy with other elements could provide a stable thermodynamic condition and act as a desirable dynamic mixing reservoir, realizing the synthesis of high-entropy alloy nanoparticles.

  • Guanghui Cao
  • , Jingjing Liang
  •  &  Lei Fu

Article | 31 May 2023

Indefinite and bidirectional near-infrared nanocrystal photoswitching

This study reports unlimited near-infrared photoswitching in inorganic avalanching nanoparticles via a discrete shift of threshold intensity mediated by internal defect-based colour centres.

  • Changhwan Lee
  • , Emma Z. Xu
  •  &  P. James Schuck

Article 17 May 2023 | Open Access

Photochromism from wavelength-selective colloidal phase segregation

A simple spectral selective active colloidal system is designed in which TiO 2 colloidal species are coded with dyes to form a photochromic swarm that adapts the appearance of incident light due to layered phase segregation.

  • , Jingyuan Chen
  •  &  Jinyao Tang

Research Highlight | 09 May 2023

Gut microbes ‘eat’ nanoparticles — leading to microbiome changes

Humans can accidentally ingest nanomaterials in consumer products, with unknown effects.

Article | 03 May 2023

Constrained C 2 adsorbate orientation enables CO-to-acetate electroreduction

A study using a copper-in-silver dilute alloy catalyst in a high-pressure gas flow reactor reports highly selective electrosynthesis of acetate from carbon monoxide.

  • , Joshua Wicks
  •  &  Yuanjie Pang

News & Views | 15 March 2023

Bow-tie particles boast a tunable twist

Particles that self-assemble from nanoribbons into bow-tie-shaped structures can be tailored to change the degree of their twist. A search for how best to quantify this twist homes in on a measure of how the bow ties respond to light.

Research Briefing | 15 February 2023

Stretchy electronic devices assembled in a Lego-like way

In current stretchable electronic devices, connection points between modules are made using commercially available pastes and break easily under mechanical deformation. An innovative connection interface has been developed to enable robust stretchable devices to be reliably assembled in a Lego‑like manner by simply pressing the interfaces of two modules together without pastes.

Research Briefing | 08 February 2023

Designer silicon nanowires produce hydrogen from water and light

Silicon nanowires that can convert light into electricity were engineered to split water into hydrogen and oxygen. When integrated with co-catalysts and suspended in water, these light-activated nanoreactors produced hydrogen gas under visible and infrared light.

Research Briefing | 14 December 2022

Array of chiral nanoparticles discriminates between enantiomers

When circularly polarized light hits an array of chiral gold nanoparticles, it generates polarized electric and magnetic waves across the surface of the nanoparticles. Chiral molecules can alter these resonances, providing a highly sensitive method to determine and quantify molecular chirality, even at very low concentrations.

Article | 14 December 2022

Enantioselective sensing by collective circular dichroism

An array of 2D crystals of isotropic, 432-symmetric chiral gold nanoparticles is shown to exhibit collective resonances with a strong and uniform chiral near field, allowing enantioselective detection by the collective circular dichroism.

  • Ryeong Myeong Kim
  • , Ji-Hyeok Huh
  •  &  Ki Tae Nam

Article | 28 November 2022

Chiral assemblies of pinwheel superlattices on substrates

Chiroptically active pinwheel assemblies on substrates are formed by tetrahedral gold nanoparticles from the effective ‘compression’ of a perovskite-like, low-density phase, thereby enabling the manufacture of metastructured coatings with special chiroptical characteristics as identified by photon-induced near-field electron microscopy and chirality measures.

  • , Jiahui Li
  •  &  Qian Chen

Article | 17 October 2022

Shape memory in self-adapting colloidal crystals

Preparing crystals held together with macromolecular bonds can create shape memory materials that can be engineered to exhibit a wide range of reversible changes useful for chemical sensing, optics and robotics.

  • Seungkyu Lee
  • , Heather A. Calcaterra
  •  &  Chad A. Mirkin

News Round-Up | 07 September 2022

Levitating nanoparticles, medieval-burial mystery and ancient femur

The latest science news, in brief.

News | 25 August 2022

‘Levitating’ nanoparticles could push the limits of quantum entanglement

Interaction between glass spheres suspended in a vacuum might one day lead to advances in quantum computing.

  • Davide Castelvecchi

Nature Index | 10 August 2022

How cross-border collaboration underpins the nanoscience revolution

Five highly cited papers that have drawn on the strengths of international partnership.

  • , David Payne
  •  &  Benjamin Plackett

Technology Feature | 25 July 2022

Light-based sensors set to revolutionize on-site testing

Nanophotonic biosensors exploit light’s properties to detect molecular interactions in real time at the point of need.

News | 20 July 2022

Molecular motor is ‘DNA origami’ milestone

Rotating device driven by Brownian motion could pave the way for more advanced nanoscale machines.

Article | 20 April 2022

Triplet fusion upconversion nanocapsules for volumetric 3D printing

  . Triplet fusion upconversion nanocapsules dispersed in a photopolymerizable resin allow for volumetric 3D printing at low-power continuous-wave excitation without support structures. 

  • Samuel N. Sanders
  • , Tracy H. Schloemer
  •  &  Daniel N. Congreve

Article | 23 March 2022

Metastable hexagonal close-packed palladium hydride in liquid cell TEM

A metastable palladium hydride is synthesized where the unique environment in the liquid cell, namely the limited quantity of Pd precursors and the continuous supply of H, resulted in the formation of the hcp phase.

  • Jaeyoung Hong
  • , Jee-Hwan Bae
  •  &  Dong Won Chun

News & Views | 19 January 2022

Nanoparticle asymmetry shapes an immune response

The chirality, or handedness, of nanoparticles is shown to be a key factor in determining how well such particles engage with the immune system — a finding that might help to inform the design of vaccines and anticancer therapeutics.

  • Alexander Hooftman
  •  &  Luke A. J. O’Neill

Article | 06 October 2021

Mastering the surface strain of platinum catalysts for efficient electrocatalysis

By depositing platinum shells on palladium-based nanocubes, the strain can be controlled by through phosphorization and dephosphorization, making it possible to tune the electrocatalytic activity of the platinum shells.

  • , Weicong Wang
  •  &  Mingshang Jin

News & Views | 08 September 2021

Hybrid light–matter states formed in self-assembling cavities

Tiny flakes of metal suspended in a solution have been observed to self-assemble into pairs separated by a narrow gap — offering a tunable system for studying combinations of light and matter known as polaritons.

  • Johannes Feist

Article | 08 September 2021

Tunable self-assembled Casimir microcavities and polaritons

Gold nanoflake pairs form by self-assembly in an aqueous ligand solution and offer stable and tunable microcavities by virtue of equilibrium between attractive Casimir forces and repulsive electrostatic forces.

  • Battulga Munkhbat
  • , Adriana Canales
  •  &  Timur O. Shegai

Article | 26 May 2021

Perovskite-type superlattices from lead halide perovskite nanocubes

Through precise structural engineering, perovskite nanocrystals are co-assembled with other nanocrystal materials to form a range of binary and ternary perovskite-type superlattices that exhibit superfluorescence.

  • Ihor Cherniukh
  • , Gabriele Rainò
  •  &  Maksym V. Kovalenko

Article | 24 March 2021

Macroscopic materials assembled from nanoparticle superlattices

Polymer-covered inorganic nanoparticles are designed to self-assemble into micrometre-sized superlattice crystallites that can subsequently be built into freestanding centimetre-scale solids with hierarchical order across seven orders of magnitude.

  • Peter J. Santos
  • , Paul A. Gabrys
  •  &  Robert J. Macfarlane

Article | 10 February 2021

Thermally reconfigurable monoclinic nematic colloidal fluids

Dispersion of colloidal disks in a nematic liquid crystal reveals several low-symmetry phases, including monoclinic colloidal nematic order, with interchange between them achieved through variations in temperature, concentration and surface charge.

  • Haridas Mundoor
  • , Jin-Sheng Wu
  •  &  Ivan I. Smalyukh

News & Views | 13 January 2021

Giant photon avalanches observed in nanoparticles

In some materials, the absorption of a single photon can trigger a chain reaction that produces a large burst of light. The discovery of these photon avalanches in nanostructures opens the way to imaging and sensing applications.

  • Andries Meijerink
  •  &  Freddy T. Rabouw

Article | 13 January 2021

Giant nonlinear optical responses from photon-avalanching nanoparticles

Room-temperature photon avalanching realized in single thulium-doped upconverting nanocrystals enables super-resolution imaging at near-infrared wavelengths of maximal biological transparency and provides a material platform potentially suitable for other optical technologies.

Article | 25 November 2020

Spin-enhanced nanodiamond biosensing for ultrasensitive diagnostics

Lateral-flow in vitro diagnostic assays based on fluorescent nanodiamonds, in which microwave-based spin manipulation is used to increase sensitivity, are demonstrated using the biotin–avidin model and by the single-copy detection of HIV-1 RNA.

  • Benjamin S. Miller
  • , Léonard Bezinge
  •  &  Rachel A. McKendry

Article | 16 September 2020

Plasmonic enhancement of stability and brightness in organic light-emitting devices

Plasmonic effects in organic light-emitting devices, which are normally considered a source of energy loss, are harnessed to enhance the stability of these devices while maintaining operational efficiency.

  • Michael A. Fusella
  • , Renata Saramak
  •  &  Julia J. Brown

Review Article | 04 March 2020

Single-particle spectroscopy for functional nanomaterials

Single-particle spectroscopic techniques that provide insights into the fundamental photophysical properties of functional nanomaterials are reviewed.

  • Jiajia Zhou
  • , Alexey I. Chizhik
  •  &  Dayong Jin

Article | 15 January 2020

Design and synthesis of multigrain nanocrystals via geometric misfit strain

Heteroepitaxy is used to precisely control the growth of Mn 3 O 4 shells on the faces of a Co 3 O 4 nanocube crystal, producing uniform grain boundary defects and highly ordered multigrain nanostructures.

  • Myoung Hwan Oh
  • , Min Gee Cho
  •  &  Taeghwan Hyeon

News & Views | 26 June 2019

Crystallization tracked atom by atom

Atoms of a metal alloy have been tracked as they form crystal nuclei — the first ordered clusters of atoms or molecules produced during crystallization. The findings might help to develop a general nucleation theory.

  • Peter G. Vekilov

Letter | 26 June 2019

Observing crystal nucleation in four dimensions using atomic electron tomography

Atomic electron tomography captures crystal nucleation in four dimensions in FePt nanoparticles, with the observed early-stage nucleation not consistent with classical nucleation theory.

  • , Yongsoo Yang

News | 28 February 2019

Night-vision ‘super-mice’ created using light-converting nanoparticles

The particles bind to photoreceptors in the eyes and convert infrared wavelengths to visible light.

  • Matthew Warren

Letter | 19 September 2018

Superstructures generated from truncated tetrahedral quantum dots

Truncated tetrahedral nanocrystals can self-assemble into one-, two- and three-dimensional superstructures.

  • Yasutaka Nagaoka
  •  &  Ou Chen

News | 29 August 2018

Making a microscopic swarm move through a maze

This magnetic ‘microswarm' makes manouvering around a maze look… mostly manageable, despite being made of millions of individual nanoparticles.

  • Shamini Bundell

Letter | 27 August 2018

All-inorganic perovskite nanocrystal scintillators

All-inorganic perovskite nanocrystals containing caesium and lead provide low-cost, flexible and solution-processable scintillators that are highly sensitive to X-ray irradiation and emit radioluminescence that is colour-tunable across the visible spectrum.

  • Qiushui Chen
  •  &  Xiaogang Liu

Letter | 20 June 2018

Self-assembly of highly symmetrical, ultrasmall inorganic cages directed by surfactant micelles

Machine-learning algorithms are used to generate single-particle three-dimensional reconstructions, revealing that highly symmetrical dodecahedral silica cages, around 10 nm in size, self-assemble in the presence of surfactant micelles.

  • , Yunye Gong
  •  &  Ulrich Wiesner

Letter | 18 April 2018

Amino-acid- and peptide-directed synthesis of chiral plasmonic gold nanoparticles

Chirality can be ‘encoded’ into gold nanoparticles by introducing chiral amino acids or peptides during the growth process, leading to the formation of helicoid morphologies.

  • Hye-Eun Lee
  • , Hyo-Yong Ahn

Letter | 11 January 2018

Bright triplet excitons in caesium lead halide perovskites

The lowest-energy exciton state in caesium lead halide perovskite nanocrystals is shown to be a bright triplet state, contrary to expectations that lowest-energy excitons should always be dark.

  • Michael A. Becker
  • , Roman Vaxenburg
  •  &  Alexander L. Efros

Nature Podcast | 14 December 2017

Podcast: Electric-eel batteries, magma viscocity, and protein shells

Advertisement

Browse broader subjects

  • Optical materials and structures
  • Nanobiotechnology
  • Nanoscale materials

Quick links

  • Explore articles by subject
  • Guide to authors
  • Editorial policies

nanoparticle review nature

IMAGES

  1. What are nanoparticles and what are they used for?

    nanoparticle review nature

  2. Schematic representation of different types of nanoparticles (NPs

    nanoparticle review nature

  3. Nanomaterials

    nanoparticle review nature

  4. Nanoparticle elasticity regulates the formation of cell membrane-coated

    nanoparticle review nature

  5. Applications Of ZnO Nanoparticles

    nanoparticle review nature

  6. Analysis of nanoparticle delivery to tumours

    nanoparticle review nature

COMMENTS

  1. Engineering precision nanoparticles for drug delivery

    Nature Reviews Drug Discovery - Advances in nanoparticle design could make substantial contributions to personalized and non-personalized medicine. In this Review, Langer, Mitchell, Peppas and ...

  2. Lipid nanoparticles for mRNA delivery

    Lipid nanoparticle-mRNA formulations have entered the clinic as coronavirus disease 2019 (COVID-19) vaccines, marking an important milestone for mRNA therapeutics. This Review discusses lipid ...

  3. Analysis of nanoparticle delivery to tumours

    Our analysis revealed that a median of 0.7% of the injected dose (ID) of the nanoparticles reached the tumour (this value was derived from 232 data sets) and that the median delivery efficiency ...

  4. Lipid nanoparticles for mRNA delivery

    A variety of materials have been developed for mRNA delivery, including lipids, lipid-like materials, polymers and protein derivatives 7 - 17. In particular, lipid nanoparticles have been thoroughly investigated and successfully entered the clinic for the delivery of small molecules 18, siRNA drugs 18 and mRNA 19 - 21.

  5. Nanoparticle therapeutics: an emerging treatment modality for cancer

    Abstract. Nanoparticles--particles in the size range 1-100 nm--are emerging as a class of therapeutics for cancer. Early clinical results suggest that nanoparticle therapeutics can show enhanced efficacy, while simultaneously reducing side effects, owing to properties such as more targeted localization in tumours and active cellular uptake.

  6. A review on nanoparticles: characteristics, synthesis, applications

    Nanoparticles (NPs) can improve the performance and efficiency of energy storage systems used in defense systems, such as batteries or fuel cells ( Morsi et al., 2022 ). In batteries, nanoparticles can be used as a cathode material to increase the battery's energy density, rate capability, and cycling stability.

  7. Nanomaterials: An overview of synthesis, classification

    Lipid-based nanoparticles are generally spherical, with diameters ranging between 10 and 100 nm. It consists of a solid core made of lipids and a matrix containing soluble lipophilic molecules. Lipid-based nanoparticles have applications in the biomedical field as a drug carrier and RNA release therapy in cancer therapy. [27, 28]

  8. Review on nanoparticles and nanostructured materials: history, sources

    Review on nanoparticles and nanostructured materials: history, sources, toxicity and regulations. Jaison Jeevanandam, 1 Ahmed Barhoum, 2, 3 Yen S Chan, 1 Alain Dufresne, 4 and Michael K Danquah 1 ... Natural nanomaterials are produced in nature either by biological species or through anthropogenic activities. The production of artificial ...

  9. Review Nanoparticles: Properties, applications and toxicities

    Abstract. This review is provided a detailed overview of the synthesis, properties and applications of nanoparticles (NPs) exist in different forms. NPs are tiny materials having size ranges from 1 to 100 nm. They can be classified into different classes based on their properties, shapes or sizes.

  10. A comprehensive review on various techniques used for synthesizing

    The crystalline nature of nanoparticles was confirmed by X-ray crystallography, as shown in Fig. 10. XRD is highly useful for stress measurements and texture analysis, in addition to chemical characterization. The phase, structural analysis and grain size of the synthesized nanoparticles were analyzed using this technique.

  11. A review of nanoparticle synthesis methods, classifications

    Top-down and bottom-up are two major nanoparticle synthesis approaches. • Sol-gel is a room-temperature method for synthesizing photocatalytic nanoparticles. • In sol-gel synthesis, temperature and pH enable the tuning of nanoparticle structure. • Composites of g-C 3 N 4 and TiO 2 are good nano catalysts for wastewater treatment.

  12. Nanoparticle synthesis assisted by machine learning

    Nature Reviews Materials - Machine learning can be applied for the controlled synthesis of nanoparticles with precise properties. This Review discusses different machine learning approaches for the...

  13. Classification and Synthesis of Nanoparticles: A Review

    The nanoparticles have a spherical shape and organic in nature. Nanosphere consists of a matrix structure and Nanocapsular is in the form of a core shell-type design. The polymeric nanoparticle has the potential to protect the molecules of the drug, join therapy and imaging.

  14. Nanoparticle classification, physicochemical properties

    Interest in nanomaterials and especially nanoparticles has exploded in the past decades primarily due to their novel or enhanced physical and chemical properties compared to bulk material. These extraordinary properties have created a multitude of innovative applications in the fields of medicine and pharma, electronics, agriculture, chemical catalysis, food industry, and many others. More ...

  15. Recent Advances in Research from Nanoparticle to Nano-Assembly: A Review

    The careful arrangement of nanomaterials (NMs) holds promise for revolutionizing various fields, from electronics and biosensing to medicine and optics. This review delves into the intricacies of nano-assembly (NA) techniques, focusing on oriented-assembly methodologies and stimuli-dependent approaches. The introduction provides a comprehensive overview of the significance and potential ...

  16. A review on the green synthesis of nanoparticles, their biological

    Green synthesis of nanoparticles (NPs) using plant materials and microorganisms has evolved as a sustainable alternative to conventional techniques that rely on toxic chemicals. Recently, green-synthesized eco-friendly NPs have attracted interest for their potential use in various biological applications. Several studies have demonstrated that green-synthesized NPs are beneficial in multiple ...

  17. Nanoparticle classification, physicochemical properties

    Nanoparticle classification, physicochemical properties, characterization, and applications: a comprehensive review for biologists ... In addition, they are often formed by non-covalent intermolecular interactions, which makes them more labile in nature and offers a route for clearance from the body ... A review on nanoparticles: their ...

  18. Nanoparticle

    nanoparticle, ultrafine unit with dimensions measured in nanometres (nm; 1 nm = 10 −9 metre). Nanoparticles exist in the natural world and are also created as a result of human activities. Because of their submicroscopic size, they have unique material characteristics, and manufactured nanoparticles may find practical applications in a ...

  19. Endocytosis: the match point of nanoparticle-based cancer therapy

    Nanomedicine has inspired a ground-breaking strategy for cancer therapy. By intelligently assembling diverse moieties to form nanoparticles, numerous functionalities such as controlled release, synergistic efficiency, and in situ killing can be achieved. The emerging nanoparticles have been designed with elevated t Journal of Materials Chemistry B Recent Review Articles

  20. Nanoreactors for particle synthesis

    Therefore, certain nanoparticle synthesis templates fall outside the scope of this Review, such as the open, nanoporous structures of molecular cages, zeolites or metal-organic frameworks (MOFs ...

  21. Sprayed Water-Based Lignin Colloidal Nanoparticle-Cellulose Nanofibril

    Sprayed Water-Based Lignin Colloidal Nanoparticle-Cellulose Nanofibril Hybrid Films with UV-Blocking Ability ... Cellulose and lignin are the two most abundant raw materials in nature, and are ideal components for functional materials. The hydrophilic interface and easy film-forming properties of cellulose nanofibrils make them excellent ...

  22. Nanomaterials: A comprehensive review of applications, toxicity, impact

    Further based on nanoparticle geometry, nanomaterials are classified as 1D, 2D, or 3D [75].According to electromagnetic properties and chemistry, NMs exist in discrete forms, suspensions, and colloids, or an agglomerated state, for example, magnetic NPs present in a bunch of an agglomerate state unless their surfaces are functionalized [77].Further on the chemical composition, NMs have been ...

  23. Catalytic system having an organotellurium ligand on graphene oxide

    First heterogeneous catalytic system, having a covalently linked hybrid bidentate organotellurium ligand [i.e., PhTe-CH 2 -CH 2 -NH 2] on the surface of graphene oxide, has been synthesized with immobilized and stabilized Pd(0) nanoparticles.To the best of our knowledge, it is the first such catalytic system in which a heterogenized organotellurium ligand has been used.

  24. Morphable materials: Researchers coax nanoparticles to reconfigure

    A view through an electron microscope of gold nanoparticles reconfiguring themselves in response to researchers changing the liquid the gold nanoparticles are suspended in—either butanol or a mix of octane and butanol. The black and white image on the left is unedited. At right, the gold nanoparticles are color-coded by their orientation.

  25. Nanoparticles

    Nanoparticles articles from across Nature Portfolio. Nanoparticles are particles that exist on a nanometre scale (i.e., below 100 nm in at least one dimension). They can possess physical ...

  26. Nanoparticle

    3 Nanoparticles. A nanoparticle is an exceedingly small particle imperceptible to the human eye and can have vastly different physical and chemical characteristics than their larger counterparts with a diameter of 1 to 100 nm. They also include larger particles as well as fibers and tubes less than 100 nm [ 17 ].

  27. Nanoparticle-specific transformations dictate nanoparticle ...

    Nature Communications - Transformation of nanoparticles (NPs) after their application can form toxic or beneficial transformation products, which affects phytophysiology. Here, the authors review ...

  28. Method development and analysis of nanoparticle size fractions from

    The nanoparticle concentration in the blue box comprises the background, or baseline, nanoparticle concentration that is due to moving components within the rig, ambient nanoparticles, and third body particles that do not interact with the tire. ... (>940 nm) regardless of the solid/semi-volatile nature of the particles. ...

  29. A popular nature park was trampled by overuse. Dogs came to the rescue

    The Lewes woodland was part of an old railway yard that had been reclaimed by nature, said Walker, 51. The wildlife trust was founded in 1988 to help restore the site in the heart of Lewes, ...

  30. Nanoparticles

    Nanoparticle asymmetry shapes an immune response. The chirality, or handedness, of nanoparticles is shown to be a key factor in determining how well such particles engage with the immune system ...