analysis of mixed method research

• Privacy Policy

Home » Mixed Methods Research – Types & Analysis

Mixed Methods Research – Types & Analysis

Table of Contents

Mixed Methods Research

Mixed methods research is an approach to research that combines both quantitative and qualitative research methods in a single study or research project. It is a methodological approach that involves collecting and analyzing both numerical (quantitative) and narrative (qualitative) data to gain a more comprehensive understanding of a research problem.

Types of Mixed Research

There are different types of mixed methods research designs that researchers can use, depending on the research question, the available data, and the resources available. Here are some common types:

Convergent Parallel Design

This design involves collecting both qualitative and quantitative data simultaneously, analyzing them separately, and then merging the findings to draw conclusions. The qualitative and quantitative data are given equal weight, and the findings are integrated during the interpretation phase.

Sequential Explanatory Design

In this design, the researcher collects and analyzes quantitative data first, and then uses qualitative data to explain or elaborate on the quantitative findings. The researcher may use the qualitative data to clarify unexpected or contradictory results from the quantitative analysis.

Sequential Exploratory Design

This design involves collecting qualitative data first, analyzing it, and then collecting and analyzing quantitative data to confirm or refute the qualitative findings. Qualitative data are used to generate hypotheses that are tested using quantitative data.

Concurrent Triangulation Design

This design involves collecting both qualitative and quantitative data concurrently and then comparing the results to find areas of agreement and disagreement. The findings are integrated during the interpretation phase to provide a more comprehensive understanding of the research question.

Concurrent Nested Design

This design involves collecting one type of data as the primary method and then using the other type of data to elaborate or clarify the primary data. For example, a researcher may use quantitative data as the primary method and qualitative data as a secondary method to provide more context and detail.

Transformative Design

This design involves using mixed methods research to not only understand the research question but also to bring about social change or transformation. The research is conducted in collaboration with stakeholders and aims to generate knowledge that can be used to improve policies, programs, and practices.

Concurrent Embedded Design

Concurrent embedded design is a type of mixed methods research design in which one type of data is embedded within another type of data. This design involves collecting both quantitative and qualitative data simultaneously, with one type of data being the primary method and the other type of data being the secondary method. The secondary method is embedded within the primary method, meaning that it is used to provide additional information or to clarify the primary data.

Data Collection Methods

Here are some common data collection methods used in mixed methods research:

Surveys are a common quantitative data collection method used in mixed methods research. Surveys involve collecting standardized responses to a set of questions from a sample of participants. Surveys can be conducted online, in person, or over the phone.

Interviews are a qualitative data collection method that involves asking open-ended questions to gather in-depth information about a participant’s experiences, perspectives, and opinions. Interviews can be conducted in person, over the phone, or online.

Focus groups

Focus groups are a qualitative data collection method that involves bringing together a small group of participants to discuss a topic or research question. The group is facilitated by a researcher, and the discussion is recorded and analyzed for themes and patterns.

Observations

Observations are a qualitative data collection method that involves systematically watching and recording behavior in a natural setting. Observations can be structured or unstructured and can be used to gather information about behavior, interactions, and context.

Document Analysis

Document analysis is a qualitative data collection method that involves analyzing existing documents, such as reports, policy documents, or media articles. Document analysis can be used to gather information about trends, policy changes, or public attitudes.

Experimentation

Experimentation is a quantitative data collection method that involves manipulating one or more variables and measuring their effects on an outcome. Experiments can be conducted in a laboratory or in a natural setting.

Data Analysis Methods

Mixed methods research involves using both quantitative and qualitative data analysis methods to analyze data collected through different methods. Here are some common data analysis methods used in mixed methods research:

Quantitative Data Analysis

Quantitative data collected through surveys or experiments can be analyzed using statistical methods. Statistical analysis can be used to identify relationships between variables, test hypotheses, and make predictions. Common statistical methods used in quantitative data analysis include regression analysis, t-tests, ANOVA, and correlation analysis.

Qualitative Data Analysis

Qualitative data collected through interviews, focus groups, or observations can be analyzed using a variety of qualitative data analysis methods. These methods include content analysis, thematic analysis, narrative analysis, and grounded theory. Qualitative data analysis involves identifying themes and patterns in the data, interpreting the meaning of the data, and drawing conclusions based on the findings.

Integration of Data

The integration of quantitative and qualitative data involves combining the results from both types of data analysis to gain a more comprehensive understanding of the research question. Integration can involve either a concurrent or sequential approach. Concurrent integration involves analyzing quantitative and qualitative data at the same time, while sequential integration involves analyzing one type of data first and then using the results to inform the analysis of the other type of data.

Triangulation

Triangulation involves using multiple sources or types of data to validate or corroborate findings. This can involve using both quantitative and qualitative data or multiple qualitative methods. Triangulation can enhance the credibility and validity of the research findings.

Mixed Methods Meta-analysis

Mixed methods meta-analysis involves the systematic review and synthesis of findings from multiple studies that use mixed methods designs. This involves combining quantitative and qualitative data from multiple studies to gain a broader understanding of a research question.

How to conduct Mixed Methods Research

Here are some general steps for conducting mixed methods research:

• Identify the research problem: The first step is to clearly define the research problem and determine if mixed methods research is appropriate for addressing it.
• Design the study: The research design should include both qualitative and quantitative data collection and analysis methods. The specific design will depend on the research question and the purpose of the study.
• Collect data : Data collection involves collecting both qualitative and quantitative data through various methods such as surveys, interviews, observations, and document analysis.
• Analyze data: Both qualitative and quantitative data need to be analyzed separately and then integrated. Analysis methods may include coding, statistical analysis, and thematic analysis.
• Interpret results: The results of the analysis should be interpreted, taking into account both the quantitative and qualitative findings. This involves integrating the results and identifying any patterns, themes, or discrepancies.
• Draw conclusions : Based on the interpretation of the results, conclusions should be drawn that address the research question and objectives.
• Report findings: Finally, the findings should be reported in a clear and concise manner, using both quantitative and qualitative data to support the conclusions.

Applications of Mixed Methods Research

Mixed methods research can be applied to a wide range of research fields and topics, including:

• Education : Mixed methods research can be used to evaluate educational programs, assess the effectiveness of teaching methods, and investigate student learning experiences.
• Health and social sciences: Mixed methods research can be used to study health interventions, understand the experiences of patients and their families, and assess the effectiveness of social programs.
• Business and management: Mixed methods research can be used to investigate customer satisfaction, assess the impact of marketing campaigns, and analyze the effectiveness of management strategies.
• Psychology : Mixed methods research can be used to explore the experiences and perspectives of individuals with mental health issues, investigate the impact of psychological interventions, and assess the effectiveness of therapy.
• Sociology : Mixed methods research can be used to study social phenomena, investigate the experiences and perspectives of marginalized groups, and assess the impact of social policies.
• Environmental studies: Mixed methods research can be used to assess the impact of environmental policies, investigate public perceptions of environmental issues, and analyze the effectiveness of conservation strategies.

Examples of Mixed Methods Research

Here are some examples of Mixed-Methods research:

• Evaluating a school-based mental health program: A researcher might use a concurrent embedded design to evaluate a school-based mental health program. The researcher might collect quantitative data through surveys and qualitative data through interviews with students and teachers. The quantitative data might be analyzed using statistical methods, while the qualitative data might be analyzed using thematic analysis. The results of the two types of data analysis could be integrated to provide a comprehensive evaluation of the program’s effectiveness.
• Understanding patient experiences of chronic illness: A researcher might use a sequential explanatory design to investigate patient experiences of chronic illness. The researcher might collect quantitative data through surveys and then use the results of the survey to inform the selection of participants for qualitative interviews. The qualitative data might be analyzed using content analysis to identify common themes in the patients’ experiences.
• Assessing the impact of a new public transportation system : A researcher might use a concurrent triangulation design to assess the impact of a new public transportation system. The researcher might collect quantitative data through surveys and qualitative data through focus groups with community members. The results of the two types of data analysis could be triangulated to provide a more comprehensive understanding of the impact of the new transportation system on the community.
• Exploring teacher perceptions of technology integration in the classroom: A researcher might use a sequential exploratory design to investigate teacher perceptions of technology integration in the classroom. The researcher might collect qualitative data through in-depth interviews with teachers and then use the results of the interviews to develop a survey. The quantitative data might be analyzed using descriptive statistics to identify trends in teacher perceptions.

When to use Mixed Methods Research

Mixed methods research is typically used when a research question cannot be fully answered by using only quantitative or qualitative methods. Here are some common situations where mixed methods research is appropriate:

• When the research question requires a more comprehensive understanding than can be achieved by using only quantitative or qualitative methods.
• When the research question requires both an exploration of individuals’ experiences, perspectives, and attitudes, as well as the measurement of objective outcomes and variables.
• When the research question requires the examination of a phenomenon in its natural setting and context, which can be achieved by collecting rich qualitative data, as well as the generalization of findings to a larger population, which can be achieved through the use of quantitative methods.
• When the research question requires the integration of different types of data or perspectives, such as combining data collected from participants with data collected from stakeholders or experts.
• When the research question requires the validation of findings obtained through one method by using another method.
• When the research question involves studying a complex phenomenon that cannot be understood by using only one method, such as studying the impact of a policy on a community’s well-being.
• When the research question involves studying a topic that has not been well-researched, and using mixed methods can help provide a more comprehensive understanding of the topic.

Purpose of Mixed Methods Research

The purpose of mixed methods research is to provide a more comprehensive understanding of a research problem than can be obtained through either quantitative or qualitative methods alone.

Mixed methods research is particularly useful when the research problem is complex and requires a deep understanding of the context and subjective experiences of participants, as well as the ability to generalize findings to a larger population. By combining both qualitative and quantitative methods, researchers can obtain a more complete picture of the research problem and its underlying mechanisms, as well as test hypotheses and identify patterns that may not be apparent with only one method.

Overall, mixed methods research aims to provide a more holistic and nuanced understanding of the research problem, allowing researchers to draw more valid and reliable conclusions, make more informed decisions, and develop more effective interventions and policies.

Advantages of Mixed Methods Research

Mixed methods research offers several advantages over using only qualitative or quantitative research methods. Here are some of the main advantages of mixed methods research:

• Comprehensive understanding: Mixed methods research provides a more comprehensive understanding of the research problem by combining both qualitative and quantitative data, which allows for a more nuanced interpretation of the data.
• Triangulation : Mixed methods research allows for triangulation, which is the use of multiple sources of data to verify findings. This improves the validity and reliability of the research.
• Addressing limitations: Mixed methods research can address the limitations of qualitative or quantitative research by compensating for the weaknesses of each method.
• Flexibility : Mixed methods research is flexible, allowing researchers to adapt the research design and methods as needed to best address the research question.
• Validity : Mixed methods research can increase the validity of the research by using multiple methods to measure the same concept.
• Generalizability : Mixed methods research can improve the generalizability of the findings by using quantitative data to test the applicability of qualitative findings to a larger population.
• Practical applications: Mixed methods research is useful for developing practical applications, such as interventions or policies, as it provides a more comprehensive understanding of the research problem.

Limitations of Mixed Methods Research

Here are some of the main limitations of mixed methods research:

• Time-consuming: Mixed methods research can be time-consuming and may require more resources than using only one research method.
• Complex data analysis: Integrating qualitative and quantitative data can be challenging and requires specialized skills for data analysis.
• Sampling bias: Mixed methods research can be subject to sampling bias, particularly if the sampling strategies for the qualitative and quantitative components are not aligned.
• Validity and reliability: Mixed methods research requires careful attention to the validity and reliability of both the qualitative and quantitative data, as well as the integration of the two data types.
• Difficulty in balancing the two methods: Mixed methods research can be difficult to balance the qualitative and quantitative methods effectively, particularly if one method dominates the other.
• Theoretical and philosophical issues: Mixed methods research raises theoretical and philosophical questions about the compatibility of qualitative and quantitative research methods and the underlying assumptions about the nature of reality and knowledge.

About the author

Muhammad Hassan

Researcher, Academic Writer, Web developer

You may also like

Qualitative Research Methods

Phenomenology – Methods, Examples and Guide

Exploratory Research – Types, Methods and...

Explanatory Research – Types, Methods, Guide

Transformative Design – Methods, Types, Guide

Survey Research – Types, Methods, Examples

• - Google Chrome

Intended for healthcare professionals

• Access provided by Google Indexer
• My email alerts
• BMA member login
• Username * Password * Forgot your log in details? Need to activate BMA Member Log In Log in via OpenAthens Log in via your institution

Search form

• Advanced search
• Search responses
• Search blogs
• Three techniques for...

Three techniques for integrating data in mixed methods studies

• Related content
• Peer review
• Alicia O’Cathain , professor 1 ,
• Elizabeth Murphy , professor 2 ,
• Jon Nicholl , professor 1
• 1 Medical Care Research Unit, School of Health and Related Research, University of Sheffield, Sheffield S1 4DA, UK
• 2 University of Leicester, Leicester, UK
• Correspondence to: A O’Cathain a.ocathain{at}sheffield.ac.uk
• Accepted 8 June 2010

Techniques designed to combine the results of qualitative and quantitative studies can provide researchers with more knowledge than separate analysis

Health researchers are increasingly using designs that combine qualitative and quantitative methods, and this is often called mixed methods research. 1 Integration—the interaction or conversation between the qualitative and quantitative components of a study—is an important aspect of mixed methods research, and, indeed, is essential to some definitions. 2 Recent empirical studies of mixed methods research in health show, however, a lack of integration between components, 3 4 which limits the amount of knowledge that these types of studies generate. Without integration, the knowledge yield is equivalent to that from a qualitative study and a quantitative study undertaken independently, rather than achieving a “whole greater than the sum of the parts.” 5

Barriers to integration have been identified in both health and social research. 6 7 One barrier is the absence of formal education in mixed methods research. Fortunately, literature is rapidly expanding to fill this educational gap, including descriptions of how to integrate data and findings from qualitative and quantitative methods. 8 9 In this article we outline three techniques that may help health researchers to integrate data or findings in their mixed methods studies and show how these might enhance knowledge generated from this approach.

Triangulation protocol

Researchers will often use qualitative and quantitative methods to examine different aspects of an overall research question. For example, they might use a randomised controlled trial to assess the effectiveness of a healthcare intervention and semistructured interviews with patients and health professionals to consider the way in which the intervention was used in the real world. Alternatively, they might use a survey of service users to measure satisfaction with a service and focus groups to explore views of care in more depth. Data are collected and analysed separately for each component to produce two sets of findings. Researchers will then attempt to combine these findings, sometimes calling this process triangulation. The term triangulation can be confusing because it has two meanings. 10 It can be used to describe corroboration between two sets of findings or to describe a process of studying a problem using different methods to gain a more complete picture. The latter meaning is commonly used in mixed methods research and is the meaning used here.

The process of triangulating findings from different methods takes place at the interpretation stage of a study when both data sets have been analysed separately (figure ⇓ ). Several techniques have been described for triangulating findings. They require researchers to list the findings from each component of a study on the same page and consider where findings from each method agree (convergence), offer complementary information on the same issue (complementarity), or appear to contradict each other (discrepancy or dissonance). 11 12 13 Explicitly looking for disagreements between findings from different methods is an important part of this process. Disagreement is not a sign that something is wrong with a study. Exploration of any apparent “inter-method discrepancy” may lead to a better understanding of the research question, 14 and a range of approaches have been used within health services research to explore inter-method discrepancy. 15

Point of application for three techniques for integrating data in mixed methods research

• Download figure
• Open in new tab
• Download powerpoint

The most detailed description of how to carry out triangulation is the triangulation protocol, 11 which although developed for multiple qualitative methods, is relevant to mixed methods studies. This technique involves producing a “convergence coding matrix” to display findings emerging from each component of a study on the same page. This is followed by consideration of where there is agreement, partial agreement, silence, or dissonance between findings from different components. This technique for triangulation is the only one to include silence—where a theme or finding arises from one data set and not another. Silence might be expected because of the strengths of different methods to examine different aspects of a phenomenon, but surprise silences might also arise that help to increase understanding or lead to further investigations.

The triangulation protocol moves researchers from thinking about the findings related to each method, to what Farmer and colleagues call meta-themes that cut across the findings from different methods. 11 They show a worked example of triangulation protocol, but we could find no other published example. However, similar principles were used in an iterative mixed methods study to understand patient and carer satisfaction with a new primary angioplasty service. 16 Researchers conducted semistructured interviews with 16 users and carers to explore their experiences and views of the new service. These were used to develop a questionnaire for a survey of 595 patients (and 418 of their carers) receiving either the new service or usual care. Finally, 17 of the patients who expressed dissatisfaction with aftercare and rehabilitation were followed up to explore this further in semistructured interviews. A shift of thinking to meta-themes led the researchers away from reporting the findings from the interviews, survey, and follow-up interviews sequentially to consider the meta-themes of speed and efficiency, convenience of care, and discharge and after care. The survey identified that a higher percentage of carers of patients using the new service rated the convenience of visiting the hospital as poor than those using usual care. The interviews supported this concern about the new service, but also identified that the weight carers gave to this concern was low in the context of their family member’s life being saved.

Morgan describes this move as the “third effort” because it occurs after analysis of the qualitative and the quantitative components. 17 It requires time and energy that must be planned into the study timetable. It is also useful to consider who will carry out the integration process. Farmer and colleagues require two researchers to work together during triangulation, which can be particularly important in mixed methods studies if different researchers take responsibility for the qualitative and quantitative components. 11

Following a thread

Moran-Ellis and colleagues describe a different technique for integrating the findings from the qualitative and quantitative components of a study, called following a thread. 18 They state that this takes place at the analysis stage of the research process (figure ⇑ ). It begins with an initial analysis of each component to identify key themes and questions requiring further exploration. Then the researchers select a question or theme from one component and follow it across the other components—they call this the thread. The authors do not specify steps in this technique but offer a visual model for working between datasets. An approach similar to this has been undertaken in health services research, although the researchers did not label it as such, probably because the technique has not been used frequently in the literature (box)

An example of following a thread 19

Adamson and colleagues explored the effect of patient views on the appropriate use of services and help seeking using a survey of people registered at a general practice and semistructured interviews. The qualitative (22 interviews) and quantitative components (survey with 911 respondents) took place concurrently.

The researchers describe what they call an iterative or cyclical approach to analysis. Firstly, the preliminary findings from the interviews generated a hypothesis for testing in the survey data. A key theme from the interviews concerned the self rationing of services as a responsible way of using scarce health care. This theme was then explored in the survey data by testing the hypothesis that people’s views of the appropriate use of services would explain their help seeking behaviour. However, there was no support for this hypothesis in the quantitative analysis because the half of survey respondents who felt that health services were used inappropriately were as likely to report help seeking for a series of symptoms presented in standardised vignettes as were respondents who thought that services were not used inappropriately. The researchers then followed the thread back to the interview data to help interpret this finding.

After further analysis of the interview data the researchers understood that people considered the help seeking of other people to be inappropriate, rather than their own. They also noted that feeling anxious about symptoms was considered to be a good justification for seeking care. The researchers followed this thread back into the survey data and tested whether anxiety levels about the symptoms in the standardised vignettes predicted help seeking behaviour. This second hypothesis was supported by the survey data. Following a thread led the researchers to conclude that patients who seek health care for seemingly minor problems have exceeded their thresholds for the trade-off between not using services inappropriately and any anxiety caused by their symptoms.

Mixed methods matrix

A unique aspect of some mixed methods studies is the availability of both qualitative and quantitative data on the same cases. Data from the qualitative and quantitative components can be integrated at the analysis stage of a mixed methods study (figure ⇑ ). For example, in-depth interviews might be carried out with a sample of survey respondents, creating a subset of cases for which there is both a completed questionnaire and a transcript. Cases may be individuals, groups, organisations, or geographical areas. 9 All the data collected on a single case can be studied together, focusing attention on cases, rather than variables or themes, within a study. The data can be examined in detail for each case—for example, comparing people’s responses to a questionnaire with their interview transcript. Alternatively, data on each case can be summarised and displayed in a matrix 8 9 20 along the lines of Miles and Huberman’s meta-matrix. 21 Within a mixed methods matrix, the rows represent the cases for which there is both qualitative and quantitative data, and the columns display different data collected on each case. This allows researchers to pay attention to surprises and paradoxes between types of data on a single case and then look for patterns across all cases 20 in a qualitative cross case analysis. 21

We used a mixed methods matrix to study the relation between types of team working and the extent of integration in mixed methods studies in health services research (table ⇓ ). 22 Quantitative data were extracted from the proposals, reports, and peer reviewed publications of 75 mixed methods studies, and these were analysed to describe the proportion of studies with integrated outputs such as mixed methods journal articles. Two key variables in the quantitative component were whether the study was assessed as attempting to integrate qualitative or quantitative data or findings and the type of publications produced. We conducted qualitative interviews with 20 researchers who had worked on some of these studies to explore how mixed methods research was practised, including how the team worked together.

Example of a mixed methods matrix for a study exploring the relationship between types of teams and integration between qualitative and quantitative components of studies* 22

• View inline

The shared cases between the qualitative and quantitative components were 21 mixed methods studies (because one interviewee had worked on two studies in the quantitative component). A matrix was formed with each of the 21 studies as a row. The first column of the matrix contained the study identification, the second column indicated whether integration had occurred in that project, and the third column the score for integration of publications emerging from the study. The rows were then ordered to show the most integrated cases first. This ordering of rows helped us to see patterns across rows.

The next columns were themes from the qualitative interview with a researcher from that project. For example, the first theme was about the expertise in qualitative research within the team and whether the interviewee reported this as adequate for the study. The matrix was then used in the context of the qualitative analysis to explore the issues that affected integration. In particular, it helped to identify negative cases (when someone in the analysis doesn’t fit with the conclusions the analysis is coming to) within the qualitative analysis to facilitate understanding. Interviewees reported the need for experienced qualitative researchers on mixed methods studies to ensure that the qualitative component was published, yet two cases showed that this was neither necessary nor sufficient. This pushed us to explore other factors in a research team that helped generate outputs, and integrated outputs, from a mixed methods study.

Themes from a qualitative study can be summarised to the point where they are coded into quantitative data. In the matrix (table ⇑ ), the interviewee’s perception of the adequacy of qualitative expertise on the team could have been coded as adequate=1 or not=2. This is called “quantitising” of qualitative data 23 ; coded data can then be analysed with data from the quantitative component. This technique has been used to great effect in healthcare research to identify the discrepancy between health improvement assessed using quantitative measures and with in-depth interviews in a randomised controlled trial. 24

We have presented three techniques for integration in mixed methods research in the hope that they will inspire researchers to explore what can be learnt from bringing together data from the qualitative and quantitative components of their studies. Using these techniques may give the process of integration credibility rather than leaving researchers feeling that they have “made things up.” It may also encourage researchers to describe their approaches to integration, allowing them to be transparent and helping them to develop, critique, and improve on these techniques. Most importantly, we believe it may help researchers to generate further understanding from their research.

We have presented integration as unproblematic, but it is not. It may be easier for single researchers to use these techniques than a large research team. Large teams will need to pay attention to team dynamics, considering who will take responsibility for integration and who will be taking part in the process. In addition, we have taken a technical stance here rather than paying attention to different philosophical beliefs that may shape approaches to integration. We consider that these techniques would work in the context of a pragmatic or subtle realist stance adopted by some mixed methods researchers. 25 Finally, it is important to remember that these techniques are aids to integration and are helpful only when applied with expertise.

Summary points

Health researchers are increasingly using designs which combine qualitative and quantitative methods

However, there is often lack of integration between methods

Three techniques are described that can help researchers to integrate data from different components of a study: triangulation protocol, following a thread, and the mixed methods matrix

Use of these methods will allow researchers to learn more from the information they have collected

Cite this as: BMJ 2010;341:c4587

Funding: Medical Research Council grant reference G106/1116

Competing interests: All authors have completed the unified competing interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare financial support for the submitted work from the Medical Research Council; no financial relationships with commercial entities that might have an interest in the submitted work; no spouses, partners, or children with relationships with commercial entities that might have an interest in the submitted work; and no non-financial interests that may be relevant to the submitted work.

Contributors: AOC wrote the paper. JN and EM contributed to drafts and all authors agreed the final version. AOC is guarantor.

Provenance and peer review: Not commissioned; externally peer reviewed.

• ↵ Lingard L, Albert M, Levinson W. Grounded theory, mixed methods and action research. BMJ 2008 ; 337 : a567 . OpenUrl FREE Full Text
• ↵ Creswell JW, Fetters MD, Ivankova NV. Designing a mixed methods study in primary care. Ann Fam Med 2004 ; 2 : 7 -12. OpenUrl Abstract / FREE Full Text
• ↵ Lewin S, Glenton C, Oxman AD. Use of qualitative methods alongside randomised controlled trials of complex healthcare interventions: methodological study. BMJ 2009 ; 339 : b3496 . OpenUrl Abstract / FREE Full Text
• ↵ O’Cathain A, Murphy E, Nicholl J. Integration and publications as indicators of ‘yield’ from mixed methods studies. J Mix Methods Res 2007 ; 1 : 147 -63. OpenUrl CrossRef Web of Science
• ↵ Barbour RS. The case for combining qualitative and quantitative approaches in health services research. J Health Serv Res Policy 1999 ; 4 : 39 -43. OpenUrl PubMed
• ↵ O’Cathain A, Nicholl J, Murphy E. Structural issues affecting mixed methods studies in health research: a qualitative study. BMC Med Res Methodol 2009 ; 9 : 82 . OpenUrl CrossRef PubMed
• ↵ Bryman A. Barriers to integrating quantitative and qualitative research. J Mix Methods Res 2007 ; 1 : 8 -22. OpenUrl CrossRef
• ↵ Creswell JW, Plano-Clark V. Designing and conducting mixed methods research . Sage, 2007 .
• ↵ Bazeley P. Analysing mixed methods data. In: Andrew S, Halcomb EJ, eds. Mixed methods research for nursing and the health sciences . Wiley-Blackwell, 2009 :84-118.
• ↵ Sandelowski M. Triangles and crystals: on the geometry of qualitative research. Res Nurs Health 1995 ; 18 : 569 -74. OpenUrl CrossRef PubMed Web of Science
• ↵ Farmer T, Robinson K, Elliott SJ, Eyles J. Developing and implementing a triangulation protocol for qualitative health research. Qual Health Res 2006 ; 16 : 377 -94. OpenUrl Abstract / FREE Full Text
• ↵ Foster RL. Addressing the epistemologic and practical issues in multimethod research: a procedure for conceptual triangulation. Adv Nurs Sci 1997 ; 20 : 1 -12. OpenUrl PubMed
• ↵ Erzerberger C, Prein G. Triangulation: validity and empirically based hypothesis construction. Qual Quant 1997 ; 31 : 141 -54. OpenUrl CrossRef Web of Science
• ↵ Fielding NG, Fielding JL. Linking data . Sage, 1986 .
• ↵ Moffatt S, White M, Mackintosh J, Howel D. Using quantitative and qualitative data in health services research—what happens when mixed method findings conflict? BMC Health Serv Res 2006 ; 6 : 28 . OpenUrl CrossRef PubMed
• ↵ Sampson FC, O’Cathain A, Goodacre S. Is primary angioplasty an acceptable alternative to thrombolysis? Quantitative and qualitative study of patient and carer satisfaction. Health Expectations (forthcoming).
• ↵ Morgan DL. Practical strategies for combining qualitative and quantitative methods: applications to health research. Qual Health Res 1998 ; 8 : 362 -76. OpenUrl Abstract / FREE Full Text
• ↵ Moran-Ellis J, Alexander VD, Cronin A, Dickinson M, Fielding J, Sleney J, et al. Triangulation and integration: processes, claims and implications. Qualitative Research 2006 ; 6 : 45 -59. OpenUrl Abstract / FREE Full Text
• ↵ Adamson J, Ben-Shlomo Y, Chaturvedi N, Donovan J. Exploring the impact of patient views on ‘appropriate’ use of services and help seeking: a mixed method study. Br J Gen Pract 2009 ; 59 : 496 -502. OpenUrl Web of Science
• ↵ Wendler MC. Triangulation using a meta-matrix. J Adv Nurs 2001 ; 35 : 521 -5. OpenUrl CrossRef PubMed Web of Science
• ↵ Miles M, Huberman A. Qualitative data analysis: an expanded sourcebook . Sage, 1994 .
• ↵ O’Cathain A, Murphy E, Nicholl J. Multidisciplinary, interdisciplinary or dysfunctional? Team working in mixed methods research. Qual Health Res 2008 ; 18 : 1574 -85. OpenUrl Abstract / FREE Full Text
• ↵ Sandelowski M. Combining qualitative and quantitative sampling, data collection, and analysis techniques in mixed-method studies. Res Nurs Health 2000 ; 23 : 246 -55. OpenUrl CrossRef PubMed Web of Science
• ↵ Campbell R, Quilty B, Dieppe P. Discrepancies between patients’ assessments of outcome: qualitative study nested within a randomised controlled trial. BMJ 2003 ; 326 : 252 -3. OpenUrl FREE Full Text
• ↵ Mays N, Pope C. Assessing quality in qualitative research. BMJ 2000 ; 320 : 50 -2. OpenUrl FREE Full Text

• What is mixed methods research?

Last updated

20 February 2023

Reviewed by

Miroslav Damyanov

Short on time? Get an AI generated summary of this article instead

By blending both quantitative and qualitative data, mixed methods research allows for a more thorough exploration of a research question. It can answer complex research queries that cannot be solved with either qualitative or quantitative research .

Analyze your mixed methods research

Dovetail streamlines analysis to help you uncover and share actionable insights

Mixed methods research combines the elements of two types of research: quantitative and qualitative.

Quantitative data is collected through the use of surveys and experiments, for example, containing numerical measures such as ages, scores, and percentages. 

Qualitative data involves non-numerical measures like beliefs, motivations, attitudes, and experiences, often derived through interviews and focus group research to gain a deeper understanding of a research question or phenomenon.

Mixed methods research is often used in the behavioral, health, and social sciences, as it allows for the collection of numerical and non-numerical data.

• When to use mixed methods research

Mixed methods research is a great choice when quantitative or qualitative data alone will not sufficiently answer a research question. By collecting and analyzing both quantitative and qualitative data in the same study, you can draw more meaningful conclusions. 

There are several reasons why mixed methods research can be beneficial, including generalizability, contextualization, and credibility. 

For example, let's say you are conducting a survey about consumer preferences for a certain product. You could collect only quantitative data, such as how many people prefer each product and their demographics. Or you could supplement your quantitative data with qualitative data, such as interviews and focus groups , to get a better sense of why people prefer one product over another.

It is important to note that mixed methods research does not only mean collecting both types of data. Rather, it also requires carefully considering the relationship between the two and method flexibility.

You may find differing or even conflicting results by combining quantitative and qualitative data . It is up to the researcher to then carefully analyze the results and consider them in the context of the research question to draw meaningful conclusions.

When designing a mixed methods study, it is important to consider your research approach, research questions, and available data. Think about how you can use different techniques to integrate the data to provide an answer to your research question.

• Mixed methods research design

A mixed methods research design  is   an approach to collecting and analyzing both qualitative and quantitative data in a single study.

Mixed methods designs allow for method flexibility and can provide differing and even conflicting results. Examples of mixed methods research designs include convergent parallel, explanatory sequential, and exploratory sequential.

By integrating data from both quantitative and qualitative sources, researchers can gain valuable insights into their research topic . For example, a study looking into the impact of technology on learning could use surveys to measure quantitative data on students' use of technology in the classroom. At the same time, interviews or focus groups can provide qualitative data on students' experiences and opinions.

• Types of mixed method research designs

Researchers often struggle to put mixed methods research into practice, as it is challenging and can lead to research bias. Although mixed methods research can reveal differences or conflicting results between studies, it can also offer method flexibility.

Designing a mixed methods study can be broken down into four types: convergent parallel, embedded, explanatory sequential, and exploratory sequential.

Convergent parallel

The convergent parallel design is when data collection and analysis of both quantitative and qualitative data occur simultaneously and are analyzed separately. This design aims to create mutually exclusive sets of data that inform each other. 

For example, you might interview people who live in a certain neighborhood while also conducting a survey of the same people to determine their satisfaction with the area.

Embedded design

The embedded design is when the quantitative and qualitative data are collected simultaneously, but the qualitative data is embedded within the quantitative data. This design is best used when you want to focus on the quantitative data but still need to understand how the qualitative data further explains it.

For instance, you may survey students about their opinions of an online learning platform and conduct individual interviews to gain further insight into their responses.

Explanatory sequential design

In an explanatory sequential design, quantitative data is collected first, followed by qualitative data. This design is used when you want to further explain a set of quantitative data with additional qualitative information.

An example of this would be if you surveyed employees at a company about their satisfaction with their job and then conducted interviews to gain more information about why they responded the way they did.

Exploratory sequential design

The exploratory sequential design collects qualitative data first, followed by quantitative data. This type of mixed methods research is used when the goal is to explore a topic before collecting any quantitative data.

An example of this could be studying how parents interact with their children by conducting interviews and then using a survey to further explore and measure these interactions.

Integrating data in mixed methods studies can be challenging, but it can be done successfully with careful planning.

No matter which type of design you choose, understanding and applying these principles can help you draw meaningful conclusions from your research.

• Strengths of mixed methods research

Mixed methods research designs combine the strengths of qualitative and quantitative data, deepening and enriching qualitative results with quantitative data and validating quantitative findings with qualitative data. This method offers more flexibility in designing research, combining theory generation and hypothesis testing, and being less tied to disciplines and established research paradigms.

Take the example of a study examining the impact of exercise on mental health. Mixed methods research would allow for a comprehensive look at the issue from different angles. 

Researchers could begin by collecting quantitative data through surveys to get an overall view of the participants' levels of physical activity and mental health. Qualitative interviews would follow this to explore the underlying dynamics of participants' experiences of exercise, physical activity, and mental health in greater detail.

Through a mixed methods approach, researchers could more easily compare and contrast their results to better understand the phenomenon as a whole.  

Additionally, mixed methods research is useful when there are conflicting or differing results in different studies. By combining both quantitative and qualitative data, mixed methods research can offer insights into why those differences exist.

For example, if a quantitative survey yields one result while a qualitative interview yields another, mixed methods research can help identify what factors influence these differences by integrating data from both sources.

Overall, mixed methods research designs offer a range of advantages for studying complex phenomena. They can provide insight into different elements of a phenomenon in ways that are not possible with either qualitative or quantitative data alone. Additionally, they allow researchers to integrate data from multiple sources to gain a deeper understanding of the phenomenon in question.  

• Challenges of mixed methods research

Mixed methods research is labor-intensive and often requires interdisciplinary teams of researchers to collaborate. It also has the potential to cost more than conducting a stand alone qualitative or quantitative study . 

Interpreting the results of mixed methods research can be tricky, as it can involve conflicting or differing results. Researchers must find ways to systematically compare the results from different sources and methods to avoid bias.

For example, imagine a situation where a team of researchers has employed an explanatory sequential design for their mixed methods study. After collecting data from both the quantitative and qualitative stages, the team finds that the two sets of data provide differing results. This could be challenging for the team, as they must now decide how to effectively integrate the two types of data in order to reach meaningful conclusions. The team would need to identify method flexibility and be strategic when integrating data in order to draw meaningful conclusions from the conflicting results.

• Advanced frameworks in mixed methods research

Mixed methods research offers powerful tools for investigating complex processes and systems, such as in health and healthcare.

Besides the three basic mixed method designs—exploratory sequential, explanatory sequential, and convergent parallel—you can use one of the four advanced frameworks to extend mixed methods research designs. These include multistage, intervention, case study , and participatory. 

This framework mixes qualitative and quantitative data collection methods in stages to gather a more nuanced view of the research question. An example of this is a study that first has an online survey to collect initial data and is followed by in-depth interviews to gain further insights.

Intervention

This design involves collecting quantitative data and then taking action, usually in the form of an intervention or intervention program. An example of this could be a research team who collects data from a group of participants, evaluates it, and then implements an intervention program based on their findings .

This utilizes both qualitative and quantitative research methods to analyze a single case. The researcher will examine the specific case in detail to understand the factors influencing it. An example of this could be a study of a specific business organization to understand the organizational dynamics and culture within the organization.

Participatory

This type of research focuses on the involvement of participants in the research process. It involves the active participation of participants in formulating and developing research questions, data collection, and analysis.

An example of this could be a study that involves forming focus groups with participants who actively develop the research questions and then provide feedback during the data collection and analysis stages.

The flexibility of mixed methods research designs means that researchers can choose any combination of the four frameworks outlined above and other methodologies , such as convergent parallel, explanatory sequential, and exploratory sequential, to suit their particular needs.

Through this method's flexibility, researchers can gain multiple perspectives and uncover differing or even conflicting results when integrating data.

When it comes to integration at the methods level, there are four approaches.

Connecting involves collecting both qualitative and quantitative data during different phases of the research.

Building involves the collection of both quantitative and qualitative data within a single phase.

Merging involves the concurrent collection of both qualitative and quantitative data.

Embedding involves including qualitative data within a quantitative study or vice versa.

• Techniques for integrating data in mixed method studies

Integrating data is an important step in mixed methods research designs. It allows researchers to gain further understanding from their research and gives credibility to the integration process. There are three main techniques for integrating data in mixed methods studies: triangulation protocol, following a thread, and the mixed methods matrix.

Triangulation protocol

This integration method combines different methods with differing or conflicting results to generate one unified answer.

For example, if a researcher wanted to know what type of music teenagers enjoy listening to, they might employ a survey of 1,000 teenagers as well as five focus group interviews to investigate this. The results might differ; the survey may find that rap is the most popular genre, whereas the focus groups may suggest rock music is more widely listened to. 

The researcher can then use the triangulation protocol to come up with a unified answer—such as that both rap and rock music are popular genres for teenage listeners. 

Following a thread

This is another method of integration where the researcher follows the same theme or idea from one method of data collection to the next. 

A research design that follows a thread starts by collecting quantitative data on a specific issue, followed by collecting qualitative data to explain the results. This allows whoever is conducting the research to detect any conflicting information and further look into the conflicting information to understand what is really going on.

For example, a researcher who used this research method might collect quantitative data about how satisfied employees are with their jobs at a certain company, followed by qualitative interviews to investigate why job satisfaction levels are low. They could then use the results to explore any conflicting or differing results, allowing them to gain a deeper understanding of job satisfaction at the company. 

By following a thread, the researcher can explore various research topics related to the original issue and gain a more comprehensive view of the issue.

Mixed methods matrix

This technique is a visual representation of the different types of mixed methods research designs and the order in which they should be implemented. It enables researchers to quickly assess their research design and adjust it as needed. 

The matrix consists of four boxes with four different types of mixed methods research designs: convergent parallel, explanatory sequential, exploratory sequential, and method flexibility. 

For example, imagine a researcher who wanted to understand why people don't exercise regularly. To answer this question, they could use a convergent parallel design, collecting both quantitative (e.g., survey responses) and qualitative (e.g., interviews) data simultaneously.

If the researcher found conflicting results, they could switch to an explanatory sequential design and collect quantitative data first, then follow up with qualitative data if needed. This way, the researcher can make adjustments based on their findings and integrate their data more effectively.

Mixed methods research is a powerful tool for understanding complex research topics. Using qualitative and quantitative data in one study allows researchers to understand their subject more deeply. 

Mixed methods research designs such as convergent parallel, explanatory sequential, and exploratory sequential provide method flexibility, enabling researchers to collect both types of data while avoiding the limitations of either approach alone.

However, it's important to remember that mixed methods research can produce differing or even conflicting results, so it's important to be aware of the potential pitfalls and take steps to ensure that data is being correctly integrated. If used effectively, mixed methods research can offer valuable insight into topics that would otherwise remain largely unexplored.

What is an example of mixed methods research?

An example of mixed methods research is a study that combines quantitative and qualitative data. This type of research uses surveys, interviews, and observations to collect data from multiple sources.

Which sampling method is best for mixed methods?

It depends on the research objectives, but a few methods are often used in mixed methods research designs. These include snowball sampling, convenience sampling, and purposive sampling. Each method has its own advantages and disadvantages.

What is the difference between mixed methods and multiple methods?

Mixed methods research combines quantitative and qualitative data in a single study. Multiple methods involve collecting data from different sources, such as surveys and interviews, but not necessarily combining them into one analysis. Mixed methods offer greater flexibility but can lead to differing or conflicting results when integrating data.

Should you be using a customer insights hub?

Do you want to discover previous research faster?

Do you share your research findings with others?

Do you analyze research data?

Start for free today, add your research, and get to key insights faster

Editor’s picks

Last updated: 30 January 2024

Last updated: 11 January 2024

Last updated: 17 January 2024

Last updated: 12 December 2023

Last updated: 30 April 2024

Last updated: 4 July 2024

Last updated: 12 October 2023

Last updated: 5 March 2024

Last updated: 6 March 2024

Last updated: 31 January 2024

Last updated: 23 January 2024

Last updated: 13 May 2024

Last updated: 20 December 2023

Latest articles

Related topics, decide what to build next, log in or sign up.

Get started for free

• News & Highlights

• Publications and Documents
• Education in C/T Science
• Browse Our Courses
• C/T Research Academy
• K12 Investigator Training
• Harvard Catalyst On-Demand
• SMART IRB Reliance Request
• Biostatistics Consulting
• Regulatory Support
• Pilot Funding
• Informatics Program
• Community Engagement
• Diversity Inclusion
• Research Enrollment and Diversity
• Harvard Catalyst Profiles

Community Engagement Program

Supporting bi-directional community engagement to improve the relevance, quality, and impact of research.

• Getting Started
• Resources for Community Engaged Implementation Science
• Resources for Equity in Research
• Community-Engaged Student Practice Placement
• Maternal Health Equity
• Youth Mental Health
• Leadership and Membership
• Past Members
• Study Review Rubric
• Community Ambassador Initiative
• Past Webinars & Podcasts
• Policy Atlas
• Community Advisory Board

For more information:

Mixed methods research.

According to the National Institutes of Health , mixed methods strategically integrates or combines rigorous quantitative and qualitative research methods to draw on the strengths of each. Mixed method approaches allow researchers to use a diversity of methods, combining inductive and deductive thinking, and offsetting limitations of exclusively quantitative and qualitative research through a complementary approach that maximizes strengths of each data type and facilitates a more comprehensive understanding of health issues and potential resolutions.¹ Mixed methods may be employed to produce a robust description and interpretation of the data, make quantitative results more understandable, or understand broader applicability of small-sample qualitative findings.

Integration

This refers to the ways in which qualitative and quantitative research activities are brought together to achieve greater insight. Mixed methods is not simply having quantitative and qualitative data available or analyzing and presenting data findings separately. The integration process can occur during data collection, analysis, or in the presentation of results.

¹ NIH Office of Behavioral and Social Sciences Research: Best Practices for Mixed Methods Research in the Health Sciences

Basic Mixed Methods Research Designs 

View image description . Figure adapted from Creswell, J. W. (2014). A concise introduction to mixed methods research. SAGE Publications.

Five Key Questions for Getting Started

• What do you want to know?
• What will be the detailed quantitative, qualitative, and mixed methods research questions that you hope to address?
• What quantitative and qualitative data will you collect and analyze?
• Which rigorous methods will you use to collect data and/or engage stakeholders?
• How will you integrate the data in a way that allows you to address the first question?

Rationale for Using Mixed Methods

• Obtain different, multiple perspectives: validation
• Build comprehensive understanding
• Explain statistical results in more depth
• Have better contextualized measures
• Track the process of program or intervention
• Study patient-centered outcomes and stakeholder engagement

Sample Mixed Methods Research Study

The EQUALITY study used an exploratory sequential design to identify the optimal patient-centered approach to collect sexual orientation data in the emergency department.

Qualitative Data Collection and Analysis : Semi-structured interviews with patients of different sexual orientation, age, race/ethnicity, as well as healthcare professionals of different roles, age, and race/ethnicity.

Builds Into : Themes identified in the interviews were used to develop questions for the national survey.

Quantitative Data Collection and Analysis : Representative national survey of patients and healthcare professionals on the topic of reporting gender identity and sexual orientation in healthcare.

Other Resources:

  Introduction to Mixed Methods Research : Harvard Catalyst’s eight-week online course offers an opportunity for investigators who want to understand and apply a mixed methods approach to their research.

Best Practices for Mixed Methods Research in the Health Sciences [PDF] : This guide provides a detailed overview of mixed methods designs, best practices, and application to various types of grants and projects.

Mixed Methods Research Training Program for the Health Sciences (MMRTP ): Selected scholars for this summer training program, hosted by Johns Hopkins’ Bloomberg School of Public Health, have access to webinars, resources, a retreat to discuss their research project with expert faculty, and are matched with mixed methods consultants for ongoing support.

Michigan Mixed Methods : University of Michigan Mixed Methods program offers a variety of resources, including short web videos and recommended reading.

To use a mixed methods approach, you may want to first brush up on your qualitative skills. Below are a few helpful resources specific to qualitative research:

• Qualitative Research Guidelines Project : A comprehensive guide for designing, writing, reviewing and reporting qualitative research.
• Fundamentals of Qualitative Research Methods – What is Qualitative Research : A six-module web video series covering essential topics in qualitative research, including what is qualitative research and how to use the most common methods, in-depth interviews, and focus groups.

View PDF of the above information.

No internet connection.

All search filters on the page have been cleared., your search has been saved..

• Sign in to my profile My Profile

Mixed Methods Research: A Guide to the Field

• By: Vicki L. Plano Clark & Nataliya V. Ivankova
• Publisher: SAGE Publications, Inc.
• Publication year: 2016
• Online pub date: December 18, 2017
• Discipline: Anthropology
• Methods: Mixed methods , Quantitative data collection , Research questions
• DOI: https:// doi. org/10.4135/9781483398341
• Keywords: attitudes , discipline , foundations , knowledge , publications , social context , teams Show all Show less
• Print ISBN: 9781483306759
• Online ISBN: 9781483398341
• Buy the book icon link

Subject index

The personal, interpersonal, and social contexts of mixed methods research are discussed more explicitly than in other mixed methods books. Chapters 2 – 10 include specific advice for applying the field of mixed methods research to the reader's own research practices. Issues and Debates sections identify the current debates in the field of mixed methods research about each topic. Application questions prompt readers to apply chapter content to their own mixed methods research practice and encourage them to grapple with the complexities of the field. In-chapter learning aids, including Learning Objectives, Chapter Key Concepts, and Key Resources, help readers master key concepts and ideas.

Front Matter

• Acknowledgements
• List of Figures, Tables, and Boxes
• Acknowledgments
• About the Authors
• Chapter 1 | Why a Guide to the Field of Mixed Methods Research? Introducing a Conceptual Framework of the Field
• Chapter 2 | What Is the Core of Mixed Methods Research Practice? Introducing the Mixed Methods Research Process
• Chapter 3 | What Is Mixed Methods Research? Considering How Mixed Methods Research Is Defined
• Chapter 4 | Why Use Mixed Methods Research? Identifying Rationales for Mixing Methods
• Chapter 5 | How to Use Mixed Methods Research? Understanding the Basic Mixed Methods Designs
• Chapter 6 | How to Expand the Use of Mixed Methods Research? Intersecting Mixed Methods With Other Approaches
• Chapter 7 | How to Assess Mixed Methods Research? Considering Mixed Methods Research Quality
• Chapter 8 | How Do Personal Contexts Shape Mixed Methods? Considering Philosophical, Theoretical, and Experiential Foundations for Mixed Methods Research
• Chapter 9 | How Do Interpersonal Contexts Shape Mixed Methods? Considering Interactions With Research Participants, Teams, and Reviewers in Mixed Methods Research
• Chapter 10 | How Do Social Contexts Shape Mixed Methods? Considering Institutional, Disciplinary, and Societal Influences on Mixed Methods Research
• Chapter 11 | Where Is Mixed Methods Research Headed? Applying the Field in Your Mixed Methods Research Practice

Back Matter

Sign in to access this content, get a 30 day free trial, more like this, sage recommends.

We found other relevant content for you on other Sage platforms.

Have you created a personal profile? Login or create a profile so that you can save clips, playlists and searches

• Sign in/register

Navigating away from this page will delete your results

Please save your results to "My Self-Assessments" in your profile before navigating away from this page.

Sign in to my profile

Please sign into your institution before accessing your profile

Sign up for a free trial and experience all Sage Learning Resources have to offer.

You must have a valid academic email address to sign up.

Get off-campus access

• View or download all content my institution has access to.

Sign up for a free trial and experience all Sage Learning Resources has to offer.

• view my profile
• view my lists

Qualitative Data Analysis

• Choosing QDA software
• Free QDA tools
• Transcription tools
• Social media research
• Mixed and multi-method research
• Network Diagrams
• Publishing qualitative data
• Student specialists

General Information

For assistance, please submit a request .  You can also reach us via the chat below, email [email protected] , or join Discord server .

If you've met with us before,  tell us how we're doing .

Stay in touch by signing up for our Data Services newsletter .

Service Desk and Chat

Bobst Library , 5th floor

Staffed Hours: Fall 2024

Mondays:  12pm - 5pm         Tuesdays:  12pm - 5pm         Wednesdays:  12pm - 5pm         Thursdays:  12pm - 5pm         Fridays:  12pm - 5pm        

Data Services closes for winter break at the end of the day on Friday, Dec. 22, 2023. We will reopen on Wednesday, Jan. 3, 2024.

Learning Mixed Methods

• Start-to-Finish Mixed Methods with MAXQDA
• Tutorials and Videos
• Suggested literature: Schoonenboom, J., Johnson, R.B. How to Construct a Mixed Methods Research Design. Köln Z Soziol 69, 107–131 (2017). https://doi.org/10.1007/s11577-017-0454-1 First step: Justify your research plan previously. Why is it relevant to integrate qualitative and quantitative methods for answering your research objectives? Then, select a research design and appropriate methods to gather information.
• Suggested resource: MAXQDA Document Variables tab Second Step: organize your qualitative sources of information with relevant variables. Afterward, identify interviews with the associated date and place, sociodemographic information of interviewees. Identify to which part of the study corresponds the information gathered, exploratory, triangulation, or confirmatory.
• Suggested resource Data Services Data Management Planning Third step: If you are dealing with large sets of text or numeric information. Use data cleaning and codebook procedures.
• Suggested resource: QDA resources at Data Services Fourth Step: Conduct the relevant Qualitative Analysis. Write preliminary Conclusions.
• Suggested literature: Cox V. (2017) Exploratory Data Analysis. In: Translating Statistics to Make Decisions. Apress, Berkeley, CA. https://doi.org/10.1007/978-1-4842-2256-0_3 Fifth Step: Conduct an in-depth exploratory analysis in the case of your quantitative data. Write preliminary conclusions.
• Suggested resource: NYU Data Services Quantitative resources Sixth Step: Do the quantitative relevant analysis. Write preliminary conclusions.
• Suggested resource: General Information about Mixed Methods in MAXQDA. Seventh Step: Quantify themes/codes in your qualitative analysis and do an exploratory analysis according to variables. Write preliminary conclusions. 
• Suggested resource: Exporting Data to Excel and SPSS with MAXQDA Eight step: if relevant, export themes and variables to do a quantitative analysis from qualitative data. Write preliminary conclusions.
• Suggested literature: Fielding, N. G. (2012). Triangulation and Mixed Methods Designs: Data Integration With New Research Technologies. Journal of Mixed Methods Research, 6(2), 124–136. https://doi.org/10.1177/1558689812437101 Ninth Step: compare the conclusions from each analysis by seeking similarities and differences. 
• Suggested literature: Bergman, M. M. (2008). 7 quality of inferences in mixed methods research: calling for an integrative framework. In Bergman, M. M. (Ed.), Advances in mixed methods research (pp. 101-119). SAGE Publications Ltd, https://www.doi.org/10. Tenth step: conclude according to validity and reliability criteria that match your research paradigm.
• Telling a Complete Story with Qualitative and Mixed Methods Research - A conversation with Dr. John W. Creswell A Sage video interview with one of the leading scholars in Mixed Methods.
• SAGE project planner A step-by-step decision-making process for planning your research project.
• Sage Methods Maps A map for choosing qualitative and quantitative research designs and analysis.
• MAXQDA’s Mixed Methods Features A brief overview of MAXQDA's Mixed-methods functions
• Introduction to Mixed Methods Functions MAXQDA NYU Data services presentation about the Mixed Methods functions in MAXQDA.
• Creswell, John W., "Steps in Conducting a Scholarly Mixed Methods Study" (2013). DBER Speaker Series. 48. https://digitalcommons.unl.edu/dberspeakers/48 A primer to mixed methods research designs and workflows.
• Johnson, R. B., Onwuegbuzie, A. J., & Turner, L. A. (2007). Toward a definition of mixed methods research. Journal of mixed methods research, 1(2), 112-133. The purpose of this article is to examine definitions of mixed methods.
• DeCuir-Gunby, J., & Schutz, P. (2017). Developing a mixed methods proposal: A practical guide for beginning researchers. SAGE Publications, Inc. https://www.doi.org/10.4135/9781483399980 An introductory guide for making mixed-methods proposals
• Schoonenboom, J. (2018). Designing mixed methods research by mixing and merging methodologies: A 13-step model. American Behavioral Scientist, 62(7), 998-1015. In this article, a 13-step model is presented that researchers can follow in designing their own multimethodology research.
• Tashakkori, A., & Teddlie, C. (2010). SAGE handbook of mixed methods in social & behavioral research (2nd ed.). SAGE Publications, Inc. https://www.doi.org/10.4135/9781506335193 A book about different approaches in mixed-methods research.
• Seawright, J., & Gerring, J. (2008). Case selection techniques in case study research: A menu of qualitative and quantitative options. Political research quarterly, 61(2), 294-308. A qualitative and quantitative guide to case selection
• << Previous: Social media research
• Next: Network Diagrams >>
• Last Updated: Oct 16, 2024 5:28 PM
• URL: https://guides.nyu.edu/QDA

PERSPECTIVE article

Mixed methods research teams: leveraging integrative teamwork for addressing complex problems.

• 1 Centre for Research in Applied Measurement and Evaluation, University of Alberta, Edmonton, AB, Canada
• 2 STEM Collegiate, Edmonton, AB, Canada

Mixed methods research teams have garnered increased attention for their leveraging of diverse disciplinary and methodological expertise in pursuit of complex problems. We advance our theoretical viewpoint of integrative mixed methods research teamwork as necessary with empirical evidence demonstrating the equipping mixed methods researchers to study complex problems involving interacting systems and lacking known solutions. Integrative mixed methods research teamwork is distinguishable by the purposeful integration of qualitative and quantitative perspectives to generate novel outcomes that are greater than the sum of individual members’ contributions. Among the key dilemmas faced by mixed methods researchers wanting to work integratively within a team is the lack of practical guidance for how to get started, how to recognize the emergence of synergistic outcomes, and how to sustain a team’s integrative work. To begin addressing this gap, we describe three practical insights gleaned from examining our team interactions and outcomes using a reflection-in-action process during a recent empirical mixed methods case study of literacy practices. In our examination, we test the practical usefulness of a theoretical framework for demystifying the development of a mixed methods research team’s integrative capacity. Our insights contribute to refining teamwork practices by identifying enablers of integrative capacity and proposing ways to overcome hindrances that have not been previously elucidated. We argue that the capacity for integrative teamwork is essential for researchers employing mixed methods, allowing them to leverage inherent synergies when addressing complex problems.

Introduction: integrative mixed methods research teamwork

Teamwork that integrates diverse disciplinary and methodological expertise is increasingly recognized as optimal for addressing more complex mixed methods research problems ( Archibald, 2023 ; Oppert et al., 2023 ; Poth, 2018 , 2019 ). Mixed methods research is well positioned to address complex problems because it uses innovations in methodology needed to address complexity ( Mertens et al., 2016 ). Complex mixed methods research problems are characterized as involving interacting systems, lacking known solutions, and benefiting from the purposeful integration of qualitative and quantitative perspectives ( Poth, 2018 ). Complicating the work of mixed methods researchers is that addressing complex problems requires unique sets of expertise and procedures that align with research questions that are difficult to predetermine. We posit complex problems benefit from mixed methods research teams who can effectively integrate individual team member contributions and accommodate emerging understandings of the required expertise and procedures.

Various accounts of mixed methods research team experiences point to challenges ( Bowers et al., 2013 ; Curry et al., 2012 , 2013 ), but a lack of focus on their synergistic potential highlights the need for guidance specific to integrative teamwork. Integrative teamwork has been distinguished from the combined efforts of researchers contributing individually as a group. Instead, integrative teamwork involves interactions that draw upon members’ broad diversity in expertise, experiences, and intuition in ways that cannot be predetermined and generate synergistic outcomes that are greater than the sum of individual members’ contributions ( Poth, 2019 ). A growing number of authors refer to the presence of ‘synergies’ emanating from disciplinarily and methodologically diverse teamwork ( Curry et al., 2013 ; Oppert et al., 2023 ; Poth, 2018 ), yet their descriptions lack the practical guidance offered in this paper. Among the key dilemmas faced by mixed methods researchers wanting to work integratively within a team involves guidance for how to get started, how to recognize the emergence of synergistic outcomes, and how to sustain a team’s integrative potential. By advancing our theoretical viewpoint with empirical evidence, we advocate the importance of integrative teamwork for mixed methods researchers tackling complex problems. We present a viewpoint that such teamwork is essential to leverage the limitless synergistic outcomes that arise from the integration of diverse expertise and lived experiences.

Providing practical guidance for developing integrative teamwork begins with complexity science to create a new, more realistic way to study complex problems ( Poth, 2018 ). As a collective of theories and conceptual tools, complexity science guides the interpretation of interactions and outcomes of integrative teamwork as an organic and holistic process. A recent effort by Poth to demystify the development of a mixed methods research team’s integrative capacity advanced a complexity-informed theoretical framework comprising four interrelated elements: membership, contributions, interactions, and performance ( Poth, 2019 ). This departs from more conventional approaches to developing mixed methods research teams in three ways: First, it depicts the team development process as non-linear, with its four elements as interrelated and the teamwork outcomes as emergent and unpredictable. Second, it considers three embedded systems (intrapersonal, interpersonal, and societal) in which teamwork takes place as influencing and being influenced by each of the interrelated elements. Third, it recognizes integrative teamwork as the emergent property emanating from the interactions that can be observed as synergistic outcomes that surpass the sum of individual team member contributions.

To guide others wanting to develop the integrative capacity of their mixed methods research teams, we tested the practical usefulness of the theoretical framework. We begin this paper by describing our team’s development process and outcomes from a recent mixed methods case study using a reflection-on-action process. Then, we discuss how the four interrelated elements (membership, contributions, interactions, and performance) of the theoretical framework together informed our relating of three practical insights to guide the development of integrative mixed methods research teamwork. Our results and discussion should be considered in light of the single empirical mixed methods case study on which this manuscript is based and the transferability of our guidance to other contexts should be further explored.

Results: experiential reflection

With the aim of demystifying the development of integrative teamwork, we use the four interrelated elements of the theoretical framework to guide our reflection-on-action process ( Mäkelä and Nimkulrat, 2018 ; Schön, 1991 ). Our process involved reviewing study documentation created by team meeting notes and personal reflections, identifying key events in our teamwork, and then discussing their significance both as individuals and as a team. Figure 1 visually depicts the non-linear team development process with double-ended arrows linking the four elements of the theoretical framework as the outer circles with each other and as influencing to and by the three embedded systems in which teamwork takes place. Intrapersonal systems describe the individual research team member’s influences, such as personal motivations, educational training, and research orientations, on both the societal and interpersonal systems. Interpersonal systems convey the social dynamics and differences in perspectives among members of a team, often attributed to lived experiences involving training and disciplinary backgrounds that influence both the societal and intrapersonal systems. Societal systems include the influences of research priorities as well as institutional influences and world events on both the interpersonal and intrapersonal systems. We represent our novel insights gleaned from our experiential reflection in the Figure in the descriptors of the four interrelated elements.

Figure 1 . The non-linear integrative mixed methods research teamwork development process.

Membership fluidity

The first element of membership involves seeking diverse team members with the aim of responsively forming a team with expertise, experiences, and perspectives relevant to addressing the complex problem. Our team’s complex problem focused on literacy practices with a specific focus on exploring the multifaceted leadership role an effective principal assumed in the deployment of evidence-based literacy practices in their school ( Kierstead et al., 2023 ). The study and our team development took place during the time period of 2020 to 2022 while society as a whole was still grappling with the uncertainty of the global Covid-19 pandemic. The impetus for our teamwork was to address the impact of reading difficulties in early elementary for students who experienced school closures due to COVID-19. It was a call for proposals from teams involving both educational faculty members and school-based community members that led us to recognize the potential of a team that integrated our diverse expertise, experiences, and roles.

From our initial meeting notes, it is evident that we acknowledged the importance of each other’s distinct contributions. Each of our four team members brought specialized and relevant knowledge to the complex problem: Georgiou is a world-class researcher on the prevention and remediation of reading difficulties with extensive experiences working with teachers in the classroom informed by his lived experiences as an elementary teacher and with assessing intervention impacts quantitatively. Kierstead is a school principal with more than 25 years of administration experience and recently completed doctoral studies on addressing reading difficulties by enhancing teachers’ content knowledge and monitoring children’s responses to intervention. Poth is a globally recognized expert in mixed methods research, qualitative research, and case studies whose work in educational settings is informed by her lived experiences as a teacher and administrator. Finally, Mack is a doctoral candidate in counseling psychology with research interests in mixed methods and invention studies. Although our team collectively possessed several qualities associated with success, such as breadth, depth, and history in our specific expertise ( NIH, 2018 ), Poth observed in her field notes that the team’s openness to the possibilities of mixed methods research was notable. This receptivity stemmed from the fact that many team members had prior experience with the necessary integration of qualitative and quantitative research. Poth also observed that the team exhibited a ‘good rapport,’ an understanding of the necessity for ‘fluidity’ in our involvement, and a willingness to engage with one another. When our team began forming, some members already had existing relationships, though they had not interacted as a group. For instance, Georgiou and Poth had been colleagues in the Faculty of Education for more than a decade, Georgiou and Kierstead had collaborated for more than five years working within school communities, and Mack had recently taken two courses instructed by Poth. We recalled that during our first meeting, identifying our diverse expertise was facilitated by the previously established relationships among us.

Unbeknownst to us, our team membership would remain stable throughout our study. The source of fluidity would not be in membership but rather in terms of the intensity of member involvement throughout the study. In Poth’s broad experience, many scenarios required new members to be sought, including but not limited to the arising need for specific expertise, graduate students moving on to other opportunities, or those working in schools who could no longer focus on research.

Mutually respectful contributions

The second element of contributions refers to building respectful relations with the aim of capitalizing on team member differences in perspectives relevant to the complex problem. Our case study mixed methods design involved integrating the lived experiences of 11 school staff (principal, learning support teacher, and classroom teachers) with the reading scores of 122 Grade 1 to 3 students in Alberta (Canada). As a reading consultant and researcher, Georgiou was well-known in the local educational community for his work with teachers and advocacy for curriculum changes relating to literacy. As a school-based principal in the local community, Kierstead worked daily with teachers and brought intimate knowledge of the types of challenges they were experiencing during the rapidly changing COVID-19 pandemic context. Key to our study’s feasibility was leveraging Georgiou’s ongoing collection of student reading data and Kierstead’s insight on the best way to organize the focus group data collection with school staff. With extensive experience collecting qualitative data, Poth and Mack worked together on the focus group protocols to tailor them to the different participant groups. Not surprisingly, challenges emerged related to competing interests that needed to be resolved. For example, the draft protocols were reviewed by Georgiou, with his feedback focused on what would be relevant questions for reading and by Kierstead for what would be relevant questions specific to the different principal and teacher roles and what time they could dedicate to our study. In so doing, we capitalized on our different perspectives to help focus our data collection activities and demonstrated mutual respect for our differing but complementary contributions. During our team reflection, we reviewed some of the challenges attributed to differing disciplinary perspectives ( Bowers et al., 2013 ; Bryman, 2006 ; Szostak, 2015 ). We surmised that our teamwork was helped by our common training in the field of educational psychology. Still, we also recognized the challenges that our differing epistemologies introduced to our work together. For example, all four had initial training in quantitative methods where we had assumed a more post-positivist viewpoint; Poth and Mack’s orientations now assumed a more constructivist viewpoint reflective of their qualitative experiences. We agreed that our commonalities in training helped us recognize the nature of these differences and navigate our differences in ways that might not be possible for others.

What is likely to be a shared challenge with other research teams is the challenge our team encountered with busy schedules, prompting us to recognize the crucial role of computer-mediated meetings in overcoming this obstacle. We found opportunities to discuss how adjustments of individual contributions are essential to our teamwork success.

In the data collection phase, Georgiou and Kierstead led the gathering of student data, while Mack focused on collecting data from school-based personnel through focus groups. Poth assumed the role of team taskmaster, organizing and overseeing the integration of student data with staff focus group insights. Poth’s request for regular meetings to check the progress of data collection and later to discuss integrated outcomes introduced a note of tension to the group dynamics. Virtual meetings emerged as a pivotal solution, facilitating frequent team meetings and demonstrated by our commitment—no scheduled meeting had ever been canceled. The team collectively interpreted this commitment as a sign of our dedication to the project. To underscore our commitment, Georgiou and Kierstead recalled joining a meeting in a car while traveling home together after meeting with teachers.

According to Poth, educating the entire team about the time and expertise required for credible integration was an ongoing and crucial effort in establishing realistic expectations for deliverables. Notably, our early identification of the need to integrate quantitative student data with qualitative school personnel data in our funding proposal allowed the team to focus on a mixed methods design. Upon reviewing our meeting notes, it was evident that individuals gradually shifted their emphasis from individual contributions to a shared focus integration. These frequent opportunities to meet and listen to one another helped build mutual respect for our unique contributions and realize our synergistic potential.

Co-created interactions

The third element of interactions revolves around the co-creation of productive team routines. It is essential to highlight the sources of tension experienced before, during, and after meetings. Acting as the taskmaster, Poth sent agendas a few days before a scheduled meeting as a way of reminding team members of the meeting purpose and preparation expectations. Team members generally found these agendas helpful, ensuring that each team member had an opportunity to articulate their contributions and to seek feedback. However, there were occasions when the agendas were perceived as potentially constraining. It’s noteworthy that, due to the dynamic nature of our teamwork and meetings, no two agendas were alike. Team members stressed the importance of allowing the agendas to evolve alongside the changing meeting purposes. In practice, the agendas were seldom followed as outlined initially. Instead, the team demonstrated an ability to adapt, with this flexibility being recognized as fostering the flow of natural conversations and allowing for the emergence of new insights that might have been missed if a rigid schedule had been strictly adhered to. The manageable size of our four-member team was also noted for its facilitation of meeting scheduling and more fluid interactions. However, one team member expressed curiosity about the scalability of this approach to a larger, more diverse group.

Team members perceived meetings as significantly impacting their understandings as the team collectively navigated a path forward through back-and-forth discussions. The opportunities for interactions were also regarded as instrumental in building a shared identity and accomplishing the study’s integration goals. Mack noted that the team meetings demonstrated that while individual contributions were necessary to the study, it was insufficient for individuals to work alongside each other. Team meetings were instrumental in clarifying understandings and identifying the next steps. A review of meeting notes indicates that team members relied on each other’s expertise to undertake the merged mixed analysis strategy that revealed four interdependent influences pointing to novel understandings of principal contributions to a school literacy culture ( Kierstead et al., 2023 ). Such novel findings emphasize the possible benefits of diversity, dissonance, and divergence in exploring methodological puzzles in mixed methods research ( Archibald, 2016 ). The team identified the sign-off process during manuscript submission as a pivotal moment where the study’s goal was realized. This process involved each team member confirming their comfort with the interpretations and conclusions as written, marking a crucial point in the development of the team’s integrative capacity ( Bowers et al., 2013 ).

Performance flexibility

The fourth element of performance highlights the need for sustaining team integrative performance and points to the need for prioritizing communication to enable the team to be flexible. Mack described a meeting that took place during data collection where it became clear from the analysis of focus group interviews that some of the participants were using the materials in different ways and to varying degrees in their classrooms. During the meeting, the team considered the importance of these differences and how best to move forward. Similarly, our team’s original timeline and plans for dissemination shifted in response to the outcomes that were generated by our integration. Our findings shed light on the complexity inherent in the roles of principals and their interactions with others in developing evidence-based literacy school cultures that improve students’ performance. This was not easy to achieve, and it took several discussions and creative thinking about how the interactions of the principal were both influencing and being influenced by others. We found being flexible with one another about the time needed to perform as a team and the audience for the deliverables as necessary.

In our teamwork, communication systems involving meetings and emails emerged as essential to sustaining interactions and conversations. Not surprisingly, we found our most ‘useful’ and innovative ideas came about not on email but in ‘real-time’ virtual meetings. We were fortunate that our team agreed to continue working together beyond the short timeline of funding. Despite facing fluctuations in availability due to competing commitments, we remained steadfast in our dedication to making our findings accessible to our audiences.

Discussion: integrative teamwork practices

To better equip researchers for tackling new challenges that demand innovative solutions, we advance three teamwork practices centred on developing communication systems, engaging in reflexive questioning, and attending to emergent properties. Effective communication represents a well-described and essential enabler for mixed methods research teams. Similar to other documented accounts ( Oppert et al., 2023 ), our team development benefited from the availability and use of computer-mediated communication technologies. In particular, the seamless integration of online team meetings and shared access to meeting documentation proved invaluable. These tools facilitated frequent interactions among team members and the building of shared understandings. Utilizing agendas as a starting place to guide meetings and meeting notes to document the next steps for accountability purposes, our team managed to avoid some of the common frustrations associated with differences in project management approaches among team members. Together, this approach allows the team to focus on developing their integrative capacity.

Reflexivity, as a practice, involves researchers explicitly acknowledging their contributions to study decisions and understanding how these contributions influence the research process ( Creswell and Poth, 2024 ). The insights gained from our team reflexivity practices underscore its value in fostering awareness and understanding of one’s positionality ( Popa and Guillermin, 2017 ) and the lenses the team brought to our mixed methods case study. Through engaging in team reflexivity, we came to recognize our growing reliance on each other’s expertise to realize our shared vision and transcend our individual boundaries. This realization contributes to our understanding of boundary transcendence and the potential of integrative teams to generate innovative solutions to complex problems and expand the existing knowledge in this practice area ( Hesse-Biber and Johnson, 2013 ).

Grounding our work in a recent theoretical framework informed by complexity science helped bridge theory with practice and inform the preparation of future educational psychology researchers for effective and integrative teamwork by bringing attention to the emergence of synergistic outcomes. This discussion seeks to extend Poth’s initial attempt to introduce the concept of emergent opportunities in mixed methods research, which we acknowledge that we still do not fully understand ( Poth, 2019 ). Growing evidence points to its underpinning role in the development of integrative capacity: Our own experiences highlight that emergence is not something that can be executed by members of a mixed methods research team based on a plan. Rather, as we experienced, team members have to be attentive listeners and responsive to conversations that appear to be leading to new understandings beyond what could have been achieved by individuals. The continual adjustments we sought in our procedures, expectations, and the ways in which we worked together were necessary, yet adopting such a mindset and way of working takes work. A mindset of continual adjustments is challenging for many researchers to adopt, including us, given that much of our methodological training has assumed stability in the context and has focused on careful planning and implementation of research plans. By sharing this perspective, we hope to inspire others to describe how their team developed, the nature of their teamwork, and the insights they gained. We aim to help mixed methods researchers realize their synergistic potential for addressing complex problems.

Data availability statement

The datasets presented in this article are not readily available because meeting and team reflection notes are not publicly available. Requests to access the datasets should be directed to Cheryl Poth [email protected] .

Ethics statement

The studies involving humans were approved by the Ethics review board of the University of Alberta. The studies were conducted in accordance with the local legislation and institutional requirements. Written informed consent for participation in this study was provided by the participants’ legal guardians/next of kin.

Author contributions

CP: Conceptualization, Formal analysis, Funding acquisition, Writing – original draft, Writing – review & editing. GG: Data curation, Funding acquisition, Writing – review & editing. EM: Writing – review & editing. MK: Writing – review & editing.

The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This work was supported by UAlberta-ATA Signature Research Collaboration Grant.

Acknowledgments

The authors acknowledge Alex Aquilina’s contributions to the organization of the initial focus groups. The author(s) also gratefully acknowledge the financial support for the research and graduate student involvement that created the opportunity for the teamwork described in this article by the Kule Institute for Advanced Study at the University of Alberta and specifically the UAlberta-Alberta Teachers Association Research Collaboration Grant (2021–2022).

Conflict of interest

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Publisher’s note

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

Archibald, M. (2016). Investigator triangulation: a collaborative strategy with potential for mixed methods research. J. Mixed Methods Res. 10, 228–250. doi: 10.1177/1558689815570092

Crossref Full Text | Google Scholar

Archibald, M. M. (2023). Virtual special issue on "collaborative practices in mixed methods research,". J. Mixed Methods Res. 17, 126–134. doi: 10.1177/15586898231163434

Bowers, B., Cohen, L., Elliot, A. E., Grabowski, D. C., Fishman, N. W., Sharkey, S. S., et al. (2013). Creating and supporting a mixed methods health services research team. Health Serv. Res. 48, 2157–2180. doi: 10.1111/1475-6773.12118

PubMed Abstract | Crossref Full Text | Google Scholar

Bryman, A. (2006). Integrating quantitative and qualitative research: how is it done? Qual. Res. J. 6, 97–113. doi: 10.1177/1468794106058877

Creswell, J. W., and Poth, C. N. (2024). Qualitative inquiry and research design: Choosing among five approaches . 5th Edn. US: Sage.

Google Scholar

Curry, L. A., Krumholz, H. M., O’Cathain, A., Plano Clark, V. L., Cherlin, E., and Bradley, E. H. (2013). Mixed methods in biomedical and health services research. Circ. Cardiovasc. Qual. Outcomes 6, 119–123. doi: 10.1161/CIRCOUTCOMES.112.967885

Curry, L. A., O’Cathain, A., Plano Clark, V. L., Aroni, R., Fetters, M., and Berg, D. (2012). The role of group dynamics in mixed methods health sciences research teams. J. Mixed Methods Res. 6, 5–20. doi: 10.1177/1558689811416941

Hesse-Biber, S., and Johnson, R. B. (2013). Coming at things differently: future directions of possible engagement with mixed methods research. J. Mixed Methods Res. 7, 103–109. doi: 10.1177/1558689813483987

Kierstead, M., Georgiou, G., Mack, E., and Poth, C. (2023). Effective school literacy culture and learning outcomes: the multifaceted leadership role of the principal. Alberta J. Educ. Res. 69, 551–567.

Mäkelä, M., and Nimkulrat, N. (2018). Documentation as a practice-led research tool for reflection on experiential knowledge. FormAkademisk 11. doi: 10.7577/formakademisk.1818

Mertens, D. M., Bazeley, P., Bowleg, L., Fielding, N. G., Maxwell, J. A., Molina-Azorin, J. F., et al. (2016). Expanding thinking through a kaleidoscopic look into the future: implications of the mixed methods international research Association’s task force report on the future of mixed methods research. J. Mixed Methods Res. 10, 221–227. doi: 10.1177/1558689816649719

NIH (2018). Best practices for mixed methods research in the health sciences . 2nd Edn. Bethesda: National Institute of Health.

Oppert, M. L., Banks, S., O’Keeffe, V., and Matthews, R. (2023). “Working in multidisciplinary and methodologically diverse teams: practical lessons from collaborating with defence-based organisations” in Handbook of mixed methods in business and management . eds. R. Cameron and X. Golenko (Edward Elgar), 94–109.

Popa, F., and Guillermin, M. (2017). Reflexive methodological pluralism: the case of environmental valuation. J. Mixed Methods Res. 11, 19–35. doi: 10.1177/1558689815610250

Poth, C. (2018). Innovation in mixed methods research: Guiding practices for integrative thinking with complexity : Sage.

Poth, C. (2019). Realizing the integrative capacity of educational mixed methods research teams: using a complexity-sensitive strategy to boost innovation. Int. J. Res. Method Educ. 42, 252–266. doi: 10.1080/1743727X.2019.1590813

Schön, D. (1991). The reflective practitioner: How professionals think in action . New York: Basic Books.

Szostak, R. (2015). “Interdisciplinary and transdisciplinary multimethod and mixed methods research” in The Oxford handbook of multimethod and mixed methods research inquiry . eds. S. N. Hesse-Biber and R. B. Johnson (Oxford: Oxford University Press), 128–143.

Keywords: mixed methods research, research teams, integrative team capacity, complex problems, complexity science

Citation: Poth C, Georgiou G, Mack E and Kierstead M (2024) Mixed methods research teams: leveraging integrative teamwork for addressing complex problems. Front. Educ . 9:1356629. doi: 10.3389/feduc.2024.1356629

Received: 15 December 2023; Accepted: 22 August 2024; Published: 02 September 2024.

Reviewed by:

Copyright © 2024 Poth, Georgiou, Mack and Kierstead. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY) . The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

*Correspondence: Cheryl Poth, [email protected]

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

• Open access
• Published: 23 October 2024

Copper hydrogen phosphate nanosheets functionalized hydrogel with tissue adhesive, antibacterial, and angiogenic capabilities for tracheal mucosal regeneration

• Pengli Wang 1 , 3 , 4   na1 ,
• Erji Gao 1   na1 ,
• Tao Wang 1 ,
• Yanping Feng 2 , 4 ,
• Yong Xu 1 ,
• Lefeng Su 2 , 4 ,
• Wei Gao 3 ,
• Zheng Ci 1 , 3 ,
• Muhammad Rizwan Younis 5 ,
• Jiang Chang 2 , 4 ,
• Chen Yang 2 , 4 &
• Liang Duan 1  

Journal of Nanobiotechnology volume  22 , Article number:  652 ( 2024 ) Cite this article

225 Accesses

Metrics details

Timely and effective interventions after tracheal mucosal injury are lack in clinical practices, which elevate the risks of airway infection, tracheal cartilage deterioration, and even asphyxiated death. Herein, we proposed a biomaterial-based strategy for the repair of injured tracheal mucosal based on a copper hydrogen phosphate nanosheets (CuHP NSs) functionalized commercial hydrogel (polyethylene glycol disuccinimidyl succinate-human serum albumin, PH). Such CuHP/PH hydrogel achieved favorable injectability, stable gelation, and excellent adhesiveness within the tracheal lumen. Moreover, CuHP NSs within the CuHP/PH hydrogel effectively stimulate the proliferation and migration of endothelial/epithelial cells, enhancing angiogenesis and demonstrating excellent tissue regenerative potential. Additionally, it exhibited significant inhibitory effects on both bacteria and bacterial biofilms. More importantly, when injected injured site of tracheal mucosa under fiberoptic bronchoscopy guidance, our results demonstrated CuHP/PH hydrogel adhered tightly to the tracheal mucosa. The therapeutic effects of the CuHP/PH hydrogel were further confirmed, which significantly improved survival rates, vascular and mucosal regeneration, reduced occurrences of intraluminal infections, tracheal stenosis, and cartilage damage complications. This research presents an initial proposition outlining a strategy employing biomaterials to mitigate tracheal mucosal injury, offering novel perspectives on the treatment of mucosal injuries and other tracheal diseases.

Introduction

The tracheal mucosa, integral to the interior lining of the trachea, plays a vital role in tracheal homeostasis by entrapping airborne particles or pathogens [ 1 ]. However, it is particularly vulnerable to damage resulting from various reasons such as inhalation injuries, endotracheal intubation, tracheostomy, and overexpansion of the endotracheal tube [ 2 ]. The post-intubation tracheal mucosal injury incidence has notably escalated in the recent wave of COVID-19, exerting a profound impact on patients’ quality of life [ 3 ]. An abundance of research suggests that untreated tracheal mucosal injuries may elevate infection risks and exacerbate tracheal cartilage deterioration, potentially precipitating complications such as tracheal stenosis, softening, necrosis, and even respiratory disorders [ 4 , 5 , 6 , 7 ]. Despite these risks, the clinical response to tracheal mucosal injury is often limited to conservative or surgical treatment following the onset of severe complications like tracheal stenosis and ignore the importance of early intervention. The prevailing occurrence of this phenomenon chiefly stems from the deficiency in immediate and potent intervention strategies. This predicament is further intensified by the trachea’s unique anatomical placemen [ 8 ]. The purpose of our study is to formulate an early and precisely tailored therapeutic approach for tracheal mucosal injuries, aiming to facilitate timely and effective repair of the compromised mucosal tissue from the onset and preemptively mitigate complications intrinsically linked to this condition.

Biomaterial-based strategies serve as an efficacious method for various mucosal injury repairs and wound healing. These biomaterials function as temporary scaffolds, performing multiple roles, such as inhibiting pathogen invasion and facilitating the migration and proliferation of cells involved in the healing process [ 9 , 10 , 11 , 12 ]. However, due to the unique arched anatomical structure of the trachea, it becomes challenging for materials to adhere to the tracheal mucosa [ 13 ]. Additionally, the rapid airflow generated during inhalation and exhalation within the airway further exacerbates the easy detachment of materials from the tracheal mucosa [ 14 ]. The dislodged material often ends up being mistakenly aspirated into the lungs, causing pulmonary foreign body infection and even respiratory distress. Therefore, these biomaterials must possess excellent adhesive properties as a primary requirement. The development of injectable tissue-adhesive hydrogel provides a novel solution for repairing internal tissue damage in the human body [ 15 ]. These hydrogels not only exhibit strong adhesion to the tracheal mucosa, preventing detachment, but they can also effectively cover mucosal lesions, forming a physical barrier. Furthermore, these hydrogels can be delivered to the site of injury noninvasively or minimally invasively using small needles or catheters, enhancing their applicability to the anatomical structure of the trachea.

An exemplar of such injected tissue-adhesive hydrogel is polyethylene glycol disuccinimidyl succinate [PEG-(SS) 2 ]-human serum albumin (HSA) hydrogel, a commercially utilized type that has seen extensive use in repairing various tissues, including skin and heart [ 16 ]. PEG-(SS) 2 -HSA (PH) hydrogel is created based on the cross-linking reaction between the free amino groups of HSA and the two-arm succinimidyl active ester groups of PEG-(SS) 2 . The active esters within the hydrogel possess the ability to bond with amino groups on the tissue surface [ 17 , 18 ]. However, prior studies indicate that pure PH hydrogel has relatively limited biofunctions, which may prove inadequate in dealing with a complex pathological environment [ 19 ]. As such, analyzing the critical requirements for tracheal mucosa injury repair and endowing PH hydrogel with corresponding functions are pivotal to its application in tracheal mucosa injury treatment.

Upon the occurrence of tracheal mucosal injury, adverse reactions such as wound infection are highly likely, given that bacteria can readily colonize the injured site due to the compromised barrier defense function of the tracheal mucosa [ 20 ]. Recent methodologies, including empirical treatments like intravenous antibiotics, are commonly employed for tackling tracheal infection resulting from mucosal injury. However, the swift emergence of antibiotic-resistant bacteria curtails their long-term use [ 21 ]. Concurrently, the destruction of the submucosal microvessels often exacerbates tracheal mucosa damage, hindering self-repair. Moreover, numerous studies have consistently confirmed the critical importance of rapid vascularization for mucosal tissue regeneration [ 22 ]. However, a noticeable absence of effective treatment strategies for submucosal microvasculature injury underscores the need for innovative solutions.

As such, implementing promoting vascularization and anti-infection measures emerge as two primary strategies for the accelerated repair of tracheal mucosal injury. Copper (II) (Cu)-based biomaterials possess the requisite characteristics to address these challenges. Cu, a vital trace element in the human body, has been shown to stimulate endothelial cell proliferation and migration, and to activate key angiogenic factors such as vascular endothelial growth factor (VEGF), thereby enhancing wound vascularization [ 23 ]. Conversely, Cu ions can infiltrate bacterial cells, disrupting critical functions like energy production and protein synthesis, and compromising cell membrane integrity, leading to bacterial death [ 24 ]. Additionally, Cu-based nanomaterials may exhibit peroxidase (POD)-like catalytic activity, enabling the conversion of excessive hydrogen peroxide at the infection site into highly toxic hydroxyl radicals, thereby achieving potent antibacterial activity [ 25 ]. Therefore, biodegradable Cu-based nanomaterials with POD-like activity could potentially serve as a bioactive ingredient to imbue the PH hydrogel with anti-bacterial and angiogenic capabilities.

In this study, we pioneer a strategy for the treatment of tracheal mucosal injuries using biomaterials, specifically through the amalgamation of PH hydrogel and a newly synthesized copper (II) hydrogen phosphate (Cu 4 H(PO 4 ) 3 ·3H 2 O, CuHP) nanosheets (NSs) (Fig.  1 ). We first synthesized and identified POD-like activity of CuHP NSs. Then we engineered the CuHP/PH composite hydrogel and subsequently validated its tissue adhesion, angiogenic, and antibacterial capabilities under in vitro conditions. Additionally, we created a rabbit model of tracheal mucosal injury to assess the CuHP/PH hydrogel’s potential in improving survival rates, vascular and mucosal regeneration, reduced occurrences of intraluminal infections, tracheal stenosis, and cartilage damage complications. Our research endeavors to offer innovative therapeutic perspectives for tracheal mucosal injury repair and the treatment of other tracheal diseases.

Display of overall experiments. CuHP NSs, PEG-(SS)2 and HAS were evenly mixed and immediately injected to the region of tracheal mucosal injury, which quickly attached onto the native tissue and transformed to a composite hydrogel with antibacterial and angiogenic capabilities due to the released Cu ions and acid-sensitive POD-like catalytic activity, thereby facilitating tracheal mucosal regeneration, preserving airway patency, and safeguarding cartilage

Experimental section

20 weight% HSA solution and PEG-(SS) 2 was purchased from Yahui Biotechnology (Hangzhou, China); Copper (II) sulfate (CuSO 4 ), Trypsin, Phosphate-buffered saline (PBS), Dulbecco’s modified Eagle’s medium high-glucose (DMEM), Fetal bovine serum (FBS), Penicillin and streptomycin were all purchased from Sigma-Aldrich unless specified otherwise.

Preparation and characterization of CuHP NSs

To synthesize CuHP NSs, 0.768 g of anhydrous CuSO 4 was initially dissolved in 10 mL H 2 O. This solution was then added to a 0.02 M PBS solution with a total volume of 500 mL. Subsequently, the solution was put on shaker for 2 h to mix evenly (120 rpm/minute). The synthesized CuHP particles were collected and centrifuged. Next, 500 mg of CuHP particles were uniformly dispersed in 1000 mL of deionized (DI) water and subjected to ultrasonication at a power of 1000 W for 24 h while being placed in an ice bath (0–20 ℃). The resulting CuHP NSs were purified through centrifugation at speeds ranging from 2000 to 65,000 rpm for 20 min and were subsequently stored for future applications.

Scanning electron microscopy (SEM, SU8010, HITACHI, Japan) was employed for microstructure observation [ 26 ], while X-ray diffraction (XRD, D8 ADVANCE, Bruker, Germany) was utilized to analyze the crystallography of CuHP NSs. Atomic force microscopy (AFM) images were acquired using Dimension ICON (Bruker, USA) [ 27 ]. Subsequently, a Zetasizer Nano-ZS90 (Malvern, England) was utilized to measure the size distribution and zeta potential of CuHP NSs.

To detect hydroxyl radicals (·OH), CuHP NSs solutions at various concentrations (0, 0.2, 0.5, and 1 mg/mL) were introduced into a 0.015% methylene blue (MB) solution. The resulting mixture was stirred for 20 min prior to the addition of 1% Hydrogen peroxide (H 2 O 2 ). Simultaneously, a CuHP NSs mixed solution at a concentration of 0.5 mg/mL was stirred for varying durations (0, 5, 10, and 20 min). UV-visible-near infrared (UV-vis-NIR) spectrophotometry was utilized to evaluate ·OH by measuring the absorbance change at 660 nm. To further investigate ·OH generation at different pH levels (pH = 6.0, pH = 7.4, and pH = 8.4), a mixed solution of 0.2 mg/mL CuHP NSs was exposed to these pH conditions for 30 s. The ability to generate ·OH was determined by monitoring the absorbance change at 660 nm using the aforementioned method.

Preparation and characterization of CuHP/PH composite hydrogel

CuHP/PH composite hydrogel was prepared as previously described [ 17 ]. Briefly, different weight ratio (0.25 wt%, 0.5 wt%, 1 wt%) of CuHP NSs were first dispersed in 1 mL HSA solution and then mixed with 1 mL PEG-(SS) 2 solution (10 wt%, dissolved in PBS) to form different CuHP/PH hydrogel, which were designated as 0.25CuHP/PH, 0.5CuHP/PH and 1CuHP/PH, respectively. PH hydrogel was prepared using the same procedure without adding CuHP NSs. The gelation and adhesive behavior of the hydrogel were evaluated using gross view, in vitro gelation, and adhesion tests. Additionally, in situ adhesion and bursting tests were conducted. Specifically, after stabilizing various shapes of PH and CuHP/PH hydrogel, a 1 × 1 cm paper was used to assess the adhesive ability of PH and CuHP/PH. Subsequently, 50 µL of hydrogel was injected in situ on the surface of the tracheal mucosa. After hydrogel stabilization, the trachea was repeatedly twisted, extruded, and bent to observe the adhesion of the hydrogel to the trachea. Furthermore, scanning electron microscopy (SEM, SU8010, HITACHI, Japan) was employed to observe the morphological characteristics of pure PH hydrogel and CuHP/PH composite hydrogel. For in vitro degradation analysis, CuHP/PH composite hydrogels (0.5CuHP/PH was taken as the representative) were immersed in phosphate buffer saline (PBS) solution with different pH conditions (pH = 7.4 and pH = 6) at 37 ℃ in a shaking bath. The residual hydrogels were photographed, and the mass of each hydrogel was weighted on days 0, 5, and 10, respectively. The degradation productions during the process were collected for further biological assay. Specifically, the released components in PBS with pH = 7.4 were collected for angiogenic assay, while the released components in PBS with pH = 6 were collected for antibacterial assay.

Bioactivity of CuHP/PH hydrogel on human umbilical vein endothelial cells (HUVECs) and tracheal epithelial cells (TECs)

100 µL CuHP/PH composite hydrogel were first injected into 96 well plates. After these hydrogel precursors gelled, 5 × 10 3 cells/well HUVECs and TECs were seeded and cultured in an incubator (5% CO 2 ) at 37 °C for 72 h with different hydrogel. Cell Counting Kit-8 (CCK-8) assay was used to determine the cellular viability by measuring the absorbance at 450 nm through the microplate reader at 24, 48 and 72 h (EPOCH2NS, BioTek, USA) [ 28 ].

To evaluate the viability of HUVECs and TECs after co-cultured with different hydrogel, the live/dead staining examined using a confocal microscope (Leica, TCS SP8 STED 3X) at 24, 48, and 72 h. F-actin and nuclei were stained with phalloidin (Yeasen) and DAPI to observe cell spreading at 48 h after cultured with PH and CuHP/PH hydrogel. Thereafter, the samples were observed and photographed using a confocal microscope (Leica, TCS SP8 STED 3X). To detect the reactive oxygen species (ROS) level in cells, ROS Kit purchased from Beyotime Biotechnology (Shanghai, China) was applied following the instruction manual. Furthermore, to evaluate the effect of different hydrogel on cell migration ability of HUVECs and TECs, 500 µL hydrogel was injected into 6 well plates to form a thin film to cover the bottom. Then, 5 × 10 5 cells/well of HUVECs and TECs were seeded on the hydrogel. After incubating at 37 °C for 24 h, a line was scratched using a 10 µL pipet tip. The floating or dead cells were washed with PBS. The cells were then cultured with different hydrogels for an additional 24 h. The cell migration activity was determined using ImageJ software. An average migration rate was calculated by using the following formula:

where R 0 is an initial scratch area and R 1 is still the unhealed scratch area.

To analyze the gene expression levels of VEGF , Hypoxia-inducible factors-1α ( HIF-1α ), Endothelial NOS ( eNOS ) and Fibroblast growth factor 2 ( FGF2 ), real-time polymerase chain reaction (RT-PCR) was carried out. HUVECs (2 × 10 4 cells/well) were seeded in a 48-well plate for 24 h. Then, the cells were treated with different hydrogel for 48 h. A MolPure cell/tissue miRNA kit was used to extract total RNA of HUVECs. Then the RNA was reverse transcribed into cDNA using Hifair II 1st Strand cDNA Synthesis SuperMix (Yeasen Biotechnology, China). The mRNA levels for VEGF , HIF-1α , eNOS and FGF2 in various samples were determined by RT-PCR. The relative primers are listed in Table 1. The 2 − △ △ Ct method was used to calculate the relative mRNA level of each gene, and GADPH was used as a reference gene.

Moreover, an in vitro vessel formation assay was performed using a Matrigel-coated plate. HUVECs were cocultured with different hydrogel for 6 h into a 48-well plate (5 × 10 4 cells/well), and the formed tubes were observed and calculated by a microscope and the ImageJ software, respectively. Specifically, Angiogenesis Analyzer was utilized in ImageJ to quantify the number of branch points within the vascular network and determine capillary length within the vascular network.

In vitro antibacterial activity

To assess the in vitro antibacterial efficacy of 0.5CuHP/PH hydrogel against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) bacteria, 200 µL different hydrogel samples were mixed with 1000 µL of bacterial solution (1 × 10 6 cfu/mL) in sterile Eppendorf tubes. After incubation at 37 °C for 24 h in a shaker (120 rpm/minute), the bacterial suspensions from the three groups were cultured with SYTO-9 and propidium iodide (PI) at 4 ℃ for 20 min. Subsequently, 10 µL bacterial suspension was placed on a glass slide and overlaid with a coverslip. The fluorescent spots were visualized using a confocal microscope (Leica, TCS SP8 STED 3X).

In addition, samples from different groups were diluted 100-fold and plated for colony growth observation. Bacterial viability was calculated using the formula:

where α is the number of colonies with the treatment of PH and 0.5CuHP/PH hydrogel and β is the number of colonies in a blank solution, ImageJ was utilized for counting bacterial colonies.

Simultaneously, 200 µL of bacterial suspension from each group was added to a 24-well plate. Then, 1 mL of broth was added, and the mixture was incubated for 48 h. The resulting biofilm was washed twice with PBS, followed by staining with 100 µL of crystal violet for 10 min. After two additional PBS washes, the biofilm was documented through photography. Finally, the biofilm was dissolved in 200 µL of 95% ethanol, and the absorbance at 570 nm was measured using a microplate reader to evaluate the formed biofilm (EPOCH2NS, BioTek, USA) [ 29 ].

Establishment of rabbit tracheal mucosal injury model

24 male New Zealand White rabbits weighing 1.5–2.0 kg were obtained from Shanghai Jiagan Experimental Animal Raising Farm (Shanghai, China). All animal experiments were approved by the Shanghai Pulmonary Hospital Ethics Committee (K19-080Y). A total of 24 rabbits were randomly divided into three groups: Blank (Sample 1 to 8 for Blank group), PH (Sample 9 to 16 for Blank group), and 0.5CuHP/PH (Sample 17 to 24 for Blank group), with 8 rabbits in each group. To establish an experimental rabbit model for assessing tracheal mucosa regeneration, a modified surgery was performed based on previously described [ 30 ].

Briefly, a 2 cm incision was made along the center after sterilizing the rabbit’s neck skin. The inner muscle tissue was carefully dissected layer-by-layer. Subsequently, a partial transection of the trachea was performed at a gap approximately 1.5 cm above and below the exposed area, serving as a sham surgery group. The mucosal layer was delicately separated along both sides of the tracheal lumen using a surgical blade. The loose mucosa was then gently lifted with tweezers to create an epithelial defect of approximately 1.5 cm in length and 50% of the trachea’s circumference in width. The cut ends of the normal tracheal ring were connected for end-to-end anastomosis. 50 µL PH or 0.5CuHP/PH hydrogel were injected onto the site of tracheal mucosal injury. All rabbits received a course of penicillin for 7 days to prevent infection and were euthanized for analyses at 10 and 20 days post-operation. The survival rate was monitored over the 20-day period. Concurrently, fiberoptic bronchoscopic examinations and gross observations were conducted to assess intraluminal infection and stenosis in the experimental rabbits at 10 and 20 days.

Evaluation of tracheal mucosal regeneration and cartilage development in vivo circumstance

To assess mucosal regeneration and tracheal lumen status following treatment with various hydrogel for 10 and 20 days, collected samples at these time points were initially fixed in buffered 10% formalin in PBS for 72 h, followed by embedding in paraffin and sectioning into 5-mm sections. Masson’s Trichrome staining was employed to visualize collagen fibers. Mucosal regeneration and airway patency (mucosal injured areas compared to natural areas) were quantified separately and calculated by averaging 5 measurements on each sample. Specifically, samples collected at 10 and 20 days were cross-sectioned at the site of mucosal injury and in the natural area. Subsequently, the luminal diameters of the mucosal injury site and the natural area were measured. The degree of airway patency was calculated by using the following formula:

where D 0 is inner diameter of natural areas and D 1 is inner diameter of mucosal injury area.

After Masson’s staining, the thickness of the tracheal mucosa at the site of injury and in the natural mucosa was observed and measured under a microscope. The degree of mucosal regeneration was calculated by using the following formula:

where T 0 is mucosal layer thickness of natural areas and T 1 is mucosal layer thickness of mucosal injury area.

Hematoxylin and eosin (HE), Safranin-O, and Masson’s Trichrome staining were utilized to evaluate tracheal structure, cartilage, and fibrous extracellular matrix (ECM) deposition. Collagen II expression was assessed via immunostaining using a rabbit polyclonal antibody targeting collagen II (ab34712, 1:100, Abcam, Cambridge, UK), followed by incubation with a horseradish peroxidase-conjugated anti-rabbit antibody (1:100, Dako, Denmark). Both antibodies were diluted in PBS and visualized using diaminobenzidine tetrahydrochloride (DAB, Dako). Biochemical evaluations related to cartilage, such as glycosaminoglycan (GAG) and total collagen contents, were performed using the dimethylmethylene blue assay (Sigma-Aldrich) and enzyme-linked immunosorbent assay, respectively.

Mechanical test

The adhesive properties of PH and CuHP/PH hydrogels were evaluated using a biomechanical analyzer (Instron-5542; Canton, USA). PH and CuHP/PH hydrogels were applied to two pieces of porcine skin tissue measuring 3 × 1 cm each, with an overlapping length of 1 × 1 cm between the two tissue pieces. After allowing for a 10-minute static period, a tensile test was performed at a rate of 2 mm/min with a 10 N load, extending to a length of 10 mm, and force-displacement data were recorded.

Following the collection of samples at 10 and 20 days, the surrounding soft tissues were carefully removed to isolate pure cartilage tissue. Subsequently, cartilage specimens from both the mucosal injury and natural areas were cut into rectangular shapes measuring 2 × 2 mm. After measuring the height of these cubes, a compression test was conducted using a biomechanical analyzer (Instron-5542; Canton, USA) equipped with a 10 N load cell, at a constant cross-head speed of 2 mm/min. The compression depth was set to 50% of the initial height of the samples. The biomechanical analyzer recorded the force-displacement curves in real time. Compressive Young’s modulus was calculated according to the force-displacement curves for statistical analysis [ 31 ].

Evaluation of epithelial regeneration, revascularization, infection, and inflammatory reactions

To further evaluate in vivo epithelial regeneration, revascularization, infection, and inflammatory reactions following treatment with different hydrogel for 10 and 20 days, histological slides were subjected to dewaxing, followed by antigen retrieval using citrate buffer. Immunofluorescence staining for Cytokeratin (Servicebio, GB122053) was utilized to assess regenerated epithelium. Immunohistochemical staining for CD31 (Servicebio, S1002) was performed to observe blood vessels. Blood vessels were counted under a 200× magnification field, with at least five random fields counted.

The mRNA levels for VEGF , eNOS and FGF2 in various samples were determined by RT-PCR according to the standard protocol as mentioned above. Fluorescence in situ hybridization (Servicebio, Eub338) staining was employed to evaluate bacterial distribution. Furthermore, to assess the inflammatory reaction, immunofluorescence staining for Tumour Necrosis Factor-α (TNF-α, Servicebio, GB11188) and Interleukin-1β (IL-1β, Servicebio, GB11113) was conducted. Random images of at least five fields were captured at 200× magnification, and the percentage of positive area relative to the total image area was calculated using ImageJ.

Statistical analysis

The mean ± standard deviation was employed to present all quantitative data ( n  ≥ 3). Statistical analyses were carried out using GraphPad Prism 8.0 software (USA). The mean values of the study parameters were compared using analysis of variance (ANOVA). A statistical significance level of p  < 0.05 was considered significant, denoted by * in the figures.

Synthesis and characterization of CuHP NSs and CuHP/PH composite hydrogel

As shown in Fig.  2 a, SEM images revealed that the synthesized NSs possessed lamellar structure with an average diameter of about 500 nm. Dynamic light scattering (DLS) analysis suggested a wide size distribution of CuHP NSs with an average hydrated particle size of about 531 nm, as shown in Figure S1 a in Supplementary File. The average zeta potential of CuHP NSs was 4.12 mV (Figure S1 b). XRD patterns further confirmed the structure and phase purity of CuHP NSs, displaying characteristic peaks at 12.879, 20.954, 29.374, 33.424, 37.106, 40.395, 47.710 and 53.233, which are ascribed to Cu 4 H(PO 4 ) 3 •3H 2 O (PDF no.31–0458) (Fig.  2 b). AFM height profile demonstrated an average thickness of about 18.77 nm (Fig.  2 c). The UV-vis-NIR absorption spectrum indicated a decrease in absorbance at 660 nm with increasing concentration of CuHP NSs (Fig.  2 d). Figure  2 e showed that the absorbance at 660 nm of the CuHP NSs solution decreased with increasing reaction time, and the color of the solution lightened over time, consistent with the change in absorbance. In Fig.  2 f, an acidic environment caused a decrease in absorbance at 660 nm of the CuHP NSs solution, and the absorbance increased with the rising pH value, particularly at pH = 8.4. These results demonstrated that CuHP NSs exhibited catalytic properties POD-like enzymes, with catalytic efficiency dependent on concentration, reaction time, and pH value.

Synthesis and characterization of CuHP nanosheets and CuHP/PH hydrogel SEM ( a ), XRD analysis ( b ), and AFM imaging ( c ) were conducted on CuHP nanosheets. The MB degradation by CuHP nanosheets under varying concentrations ( d ), durations ( e ), and pH levels ( f ). Gross observation ( g ) and determination of gelation time ( h ) were performed for CuHP/PH hydrogel. In vitro gelation studies for both PH and CuHP/PH hydrogel were conducted ( i ). Adhesion assessment of CuHP/PH hydrogel was carried out in situ ( j ). Intratracheal injection of CuHP/PH hydrogel under fiberoptic bronchoscopy guidance ( k )

Furthermore, CuHP NSs were mixed into PH hydrogel to fabricate CuHP/PH hydrogel. Overall, the gelation process remained undisturbed following the addition of CuHP NSs at various concentrations (Fig.  2 g), and the gelation time of different groups showed no statistically significant (Fig.  2 h). In vitro gelation experiment showed PH and CuHP/PH hydrogel could be formed and stabilized in different shapes (Fig.  2 i). The adhesion of the hydrogel in vitro was assessed by the adhesion of the hydrogel to paper (Figure S2 ), indicating PH and CuHP/PH hydrogel could tightly adhere to paper. While Fig.  2 j showed PH and CuHP/PH hydrogel displayed excellent tissue adhesion even under repeating extruding, twisting, bending the trachea. The adhesive properties of PH and CuHP/PH hydrogels were further evaluated by a tensile test. The results indicated that CuHP nanosheets do not affect the adhesive properties of PH hydrogel, with a maximum tensile force of approximately 0.08 N (Figure S3 ). Furthermore, as shown in Fig.  2 k, Videoclip S1 and Figure S4 in Supplementary File, CuHP/PH hydrogel displayed the capability for in situ tracheal injection and sequentially form an adhesion gel with even distribution of CuHP NSs Besides, the degradation processes of CuHP/PH hydrogels in different pH conditions were evaluated. As shown in Figure S5 , CuHP/PH hydrogel decreased continuously over time in PBS under both the neutral (pH = 7.4) and acidic (pH = 6) conditions. After 10 days’ degradation, 46.26 ± 4.57 wt% and 24.12 ± 3.17 wt% of the hydrogel was retained in neutral and acidic conditions, respectively, indicating the faster degradation rate in acidic environments. All these results collectively confirmed the successful fabrication of the injectable CuHP/PH hydrogel with tissue adhesive and biodegradable ability.

Bioactivity of CuHP/PH hydrogel on HUVECs and TECs

In vitro cellular proliferation ability of various concentrations of CuHP/PH hydrogel was evaluated using a CCK-8 assay kit on HUVECs and TECs. The quantitative analysis for HUVECs demonstrated that the 0.5CuHP/PH group exhibited a higher absorbance at 450 nm in all groups, indicating enhanced proliferation of HUVECs in this group (Fig.  3 a). On the other hand, the quantitative results for TECs showed no statistically significant difference among the PH, 0.25CuHP/PH, and 0.5CuHP/PH groups (Fig.  3 b). Notably, both Fig.  3 a and b showed that the 1CuHP/PH group hydrogel had a pronounced inhibitory effect on the growth of HUVECs and TECs. Given its good cellular proliferation ability, the 0.5CuHP/PH hydrogel was selected for subsequent cell experiments. Live/dead staining demonstrated that HUVECs in the 0.5CuHP/PH group exhibited better viability with minimal cell death, while TECs in the 0.5CuHP/PH group showed no obvious differences compared to the PH group (Fig.  3 c and d). We further detected ROS level in HUVECs after incubation with 0.5CuHP/PH for 3 days. As shown in Figure S6 , 0.5CuHP/PH hydrogel did not induce a distinct change in fluorescence intensity of ROS compared with the Blank group, confirming the good biocompatibility of the hydrogel. Positive control group operated following the kit demonstrated the effectiveness of the ROS probe.

Biocompatibility of CuHP/PH hydrogel on HUVECs and TECs. ( a - b ) Impact of varied concentrations of CuHP/PH (0.25, 0.5, 1 wt%) hydrogel on the proliferation of HUVECs and TECs; ( c - d ) Live/dead staining for PH and 0.5CuHP/PH hydrogel on HUVEC and TECs; Cell scratch assay ( e ) and quantitative outcomes ( f ) regarding HUVEC cell migration ability; Cell scratch assay ( g ) and quantitative outcomes ( h ) regarding epithelial cell migration ability; ( i ) Expression levels of key angiogenesis-related genes in HUVECs; Tube formation ( j ) and quantitative outcomes regarding branch points and capillary length ( k ) of HUVECs. (h: hours; *, p  < 0.05)

Besides, the distribution of microfilaments in HUVECs and epithelial cells is distinctly visible through F-actin/DAPI staining, indicating favorable cellular extension (Figure S7 ). Cellular migration was assessed using a cell scratch assay. Results showed that the 0.5CuHP/PH group (74.41 ± 1.81%) exhibited enhanced cellular migration of HUVECs compared to the Blank (60.87 ± 1.15%) and PH groups (62.24 ± 1.42%) (Fig.  3 e and f). A similar trend was also observed in epithelial cells as both PH and 0.5CuHP/PH showed a significant improvement in cellular migration compared to the Blank, while the cell migration rate in the 0.5CuHP/PH group was significantly higher than that in the PH group (Fig.  3 g and h). The quantitative results revealed the same trend (Fig.  3 h).

Comparison with the Blank and PH groups, the quantitative RT-PCR results for the 0.5CuHP/PH group showed higher expression of angiogenic genes, including VEGF , eNOS , HIF-1α and FGF2 (Fig.  3 i). Additionally, the tube formation assay demonstrated the same trend. Figure  3 j and k revealed that the 0.5CuHP/PH group displayed a significantly higher number of tubes and increased tube length compared to the other groups. Such biological activity may be ascribed to the released components from the CuHP/PH hydrogel as the degraded products collected from the in vitro degradation experiments also displayed a significantly higher number of formed tubes and increased tube length compared to Blank (Figure S8 in Supplementary File). These findings highlighted the enhanced angiogenic potential of CuHP/PH hydrogel, indicating its suitability for promoting angiogenesis and tissue regeneration applications.

To evaluate the in vitro antibacterial activity, both Gram-negative ( E. coli ) and Gram-positive ( S. aureus ) bacteria were cultured in Petri dishes after co-culturing with PBS, PH, and 0.5CuHP/PH hydrogel for 24 h, respectively. Live/dead fluorescence staining was conducted to verify the antibacterial effect of 0.5CuHP/PH hydrogel. As shown in Fig.  4 a and b, both the Blank and PH groups exhibited a strong green fluorescence signal and a weak red fluorescence signal, indicating high bacterial activity. Interestingly, in comparison to the Blank group, the PH group showed a stronger green fluorescence signal. In contrast, the 0.5CuHP/PH group exhibited mostly red fluorescence-labeled bacteria, indicating severe bacterial damage and excellent antibacterial activity of 0.5CuHP/PH hydrogel. Additionally, the images of E. coli and S. aureus grown on agar plates revealed similar results. The 0.5CuHP/PH group exhibited a dramatic reduction in bacterial viability, while the PH group showed higher viability than the Blank and 0.5CuHP/PH groups (Fig.  4 c and d). To confirm the antibacterials ability of the released components from the CuHP/PH hydrogel, the degraded products collected from the in vitro degradation experiments were co-cultured with S. aureus and E. coli. Figure S9 revealed that the released components from CuHP/PH hydrogel also possessed excellent antibacterial activity against both S. aureus and E. coli . Furthermore, biofilms stained with crystal violet demonstrated that 0.5CuHP/PH hydrogel induced the greatest damage to the biofilm, and PH hydrogel exhibited more biofilm production. Relative biofilm biomass confirmed these results (Fig.  4 e and f). Overall, all the findings consistently revealed that 0.5CuHP/PH hydrogel can achieve efficient antibacterial and anti-biofilm efficacy, even if PH hydrogel possesses the opposite effect on bacteria.

Antibacterial activity of CuHP/PH hydrogel against  S. aureus  and  E. coli . ( a ) S. aureus and ( b ) E. coli was subjected to live/dead staining using green fluorescence (SYTO9) and red fluorescence (PI) after treatment with PBS, PH, and 0.5CuHP/PH hydrogel, respectively. ( c ) Images depict E. coli and S. aureus growth on agar plates under different treatments. ( d ) Quantitative assessment of the inhibition percentage of E. coli and S. aureus . ( e ) Visualization of E. coli and S. aureus biofilms stained with crystal violet. ( f ) OD values at 570 nm of biofilms stained with crystal violet. (*,  p  < 0.05)

To mitigate potential surgical-induced influences on experimental outcomes, a sham control group was implemented. In this sham control group, aside from the possible occurrence of slight granulation tissue proliferation at the anastomosis site, no indications of infection, inflammation, or luminal narrowing were observed (Figure S10 ). After the tracheal mucosal injury surgery (Fig.  5 a), the survival rates of the experimental rabbits were monitored (Fig.  5 b). Rabbits in the 0.5CuHP/PH group exhibited a better survival rate of 80% compared to the Blank and PH groups. Endoscopic images (Fig.  5 c) revealed that the Blank and PH groups showed more purulent exudates at 10 days, while the 0.5CuHP/PH group at 10 days had a smooth lumen without purulent exudates or lumen obstruction. Massive purulent exudates were still observed in the Blank group at 20 days, and the lumen was blocked. In contrast, the PH group at 20 days showed no signs of purulent exudate but exhibited granulation tissue. The 0.5CuHP/PH group still maintained an unobstructed lumen at 20 days. Gross view (Fig.  5 d) further confirmed the results of the endoscopic images. Both the Blank and PH groups showed more purulent exudates and obvious granulation tissue proliferation at 10 days and 20 days, while the 0.5CuHP/PH group had a smoother lumen similar to the natural tracheal mucosa.

Treatment of injured tracheal mucosa in a rabbit model. ( a ) Elucidation of the surgical methodology for treating injured tracheal mucosa with CuHP/PH hydrogel; ( b ) Evaluation of the probability of survival in experimental rabbits post-surgery (Sample 1 to 8 for Blank group; Sample 9–16 for PH group; Sample 17–24 for CuHP group). Endoscopic images ( c ) and gross view ( d ) showcase the tracheal lumen condition after treatment with Blank (Samples 2 at 10 days and Sample 8 at 20 days), PH (Samples 10 at 10 days and Sample 14 at 20 days), and 0.5CuHP/PH hydrogels (Samples 19 at 10 days and Sample 21 at 20 days). (Purulent secretion is indicated by black arrows; granulation tissue is denoted by red arrows; D: defected tracheal mucosa; N: normal mucosa; *, p  < 0.05)

Masson’s trichrome staining was performed to evaluate the condition of mucosal regeneration among these groups (Fig.  6 a). The 0.5CuHP/PH group displayed histological characteristics similar to that of natural mucosa, including regenerated soft tissue thickness and mature epithelial tissue at 10 and 20 days. More mature epithelial tissue was observed at 20 days. Conversely, the PH group demonstrated obvious soft tissue hyperplasia and lacked distinct mucosa formation at 10 and 20 days. Notably, the Blank group exhibited visible cartilage exposure at 10 days, while substantial soft tissue thickening was apparent at 20 days.

The evaluation of mucosal regeneration and the status of airway lumen following treatment with various hydrogel at 10 and 20 days. ( a ) Masson’s trichrome staining was conducted on samples from Blank (Samples 2 at 10 days and Sample 8 at 20 days), PH (Samples 10 at 10 days and Sample 14 at 20 days), and 0.5CuHP/PH groups (Samples 19 at 10 days and Sample 21 at 20 days); ( b - e ) Quantitative analyses of mucosal regeneration and airway patency were performed. (Blue box: regenerated epithelium; Green box: natural epithelium; Scale bar = 500 μm; *, p  < 0.05)

Quantitative analysis of the degree of mucosal regeneration revealed that the 0.5CuHP/PH group presented a similar mucosal thickness to natural mucosa at 10 and 20 days. Significantly, the PH group showed thicker regenerated mucosal tissue at 10 and 20 days, which might be granulation tissue and scar hyperplasia. Whereas the Blank group had almost no regenerated mucosal tissue at 10 days but thicker regenerated mucosal tissue at 20 days (Fig.  6 b and c). Quantitative measurements of airway patency further revealed that the 0.5CuHP/PH group displayed an unobstructed lumen in contrast to the Blank and PH groups. It is noteworthy that the Blank group showed severe tracheal stenosis especially at 10 days, which might be attributed to disordered cartilage arrangement. The PH group exhibited significant tracheal stenosis at 10 and 20 days, possibly due to disordered cartilage and proliferating tissue (Fig.  6 d and e).

To further assess the development of cartilage after tracheal mucosal injury, HE, collagen II, Safranin-O, and Masson’s trichrome staining were conducted. HE staining indicated that cartilage in the 0.5CuHP/PH group was more homogeneous and more prominent cartilage lacunae than that in the Blank and PH groups at 10 and 20 days. Collagen II, Safranin-O, and Masson’s trichrome staining indicated that more cartilage-specific ECM was degraded in the Blank and PH groups than in the 0.5CuHP/PH group. The immunohistochemical collagen II staining showed strong positivity in the 0.5CuHP/PH group and weak positivity in the Blank group. Safranin-O staining showed similar results. Significantly, the intensity of cartilage-specific ECM staining in the PH group was weaker than in the 0.5CuHP/PH group but stronger than in the Blank group, which could be due to the defensive function of the PH hydrogel. Blank and PH groups showed that the intensity of cartilage-specific ECM staining was weaker at 20 days than at 10 days (Fig.  7 a). Quantitative data of GAG content, collagen II content, and Young’s modulus further demonstrated the results. A higher level of GAG content and total collagen II content were observed in the samples of the 0.5CuHP/PH group, which was closest to natural tracheal cartilage. While the Blank and PH groups showed a significant decrease, especially the Blank group (Fig.  7 b and c). Quantitative data of Young’s modulus revealed that samples in the 0.5CuHP/PH group still maintained a higher level of mechanical strength compared with the Blank and PH groups (Fig.  7 d). All these results revealed that 0.5CuHP/PH hydrogel has beneficial effects on cartilage protection.

Development of tracheal cartilage following treatment with distinct hydrogel for 10 and 20 days. ( a ) HE, Collagen II, Safranin-O, and Masson’s trichrome staining were performed on samples from the Blank (Samples 3 at 10 days and Sample 7 at 20 days), PH (Samples 11 at 10 days and Sample 16 at 20 days), and 0.5CuHP/PH (Samples 18 at 10 days and Sample 22 at 20 days) groups; ( b ) Quantitative analysis of GAG content, ( c ) total collagen content, and ( d ) Young’s modulus was carried out. (N: natural tracheal cartilage; Scale bar = 200 μm; *, p  < 0.05)

In vivo evaluation of reepithelization, revascularization, infection, and inflammatory reactions

To verify the effects of CuHP/PH hydrogel on mucosal regeneration, immunofluorescence staining of cytokeratin and immunohistochemical staining of CD31 were conducted. Histological examination demonstrated faster regenerated epithelium and more regenerated vasculature in the 0.5CuHP/PH group when compared with the Blank and PH groups, as evidenced by strong positive immunofluorescence staining of cytokeratin (Fig.  8 a1-a6) and immunohistochemical staining of CD31 (Fig.  8 b1-b6). Remarkably, the Blank group displayed minimal staining of regenerated epithelium at both 10 and 20 days. In contrast, both the PH and 0.5CuHP/PH groups exhibited more pronounced staining of regenerated epithelium at 20 days compared to 10 days. Quantitative analysis of CD31 (Fig.  8 f) validated that the 0.5CuHP/PH group had excellent revascularization. The in vivo quantitative RT-PCR results revealed elevated expression levels of angiogenic genes, including FGF2 , VEGF , and eNOS , in the 0.5CuHP/PH group. This observation serves as additional confirmation that the 0.5CuHP/PH group exhibited superior revascularization (Figure S11 ).

Assessment of in vivo epithelial regeneration, revascularization, infection, and inflammatory reactions after treatment with various hydrogel at 10 and 20 days. Immunofluorescence staining for cytokeratin ( a1 - a6 ); Immunohistochemical staining for CD31 ( b1 - b6 ); Immunofluorescence staining for bacteria ( c1 - c6 ), TNF-α ( d1 - d6 ), and IL-1β ( e1 - e6 ) were performed on samples from the Blank (Samples 2 at 10 days and Sample 6 at 20 days), PH (Samples 10 at 10 days and Sample 15 at 20 days), and 0.5CuHP/PH (Samples 20 at 10 days and Sample 24 at 20 days) groups. Quantitative analyses were conducted for neonatal blood vessels ( f ), bacteria ( g ), TNF-α ( h ), and IL-1β density ( i ). (Scale bar = 20 μm; *, p  < 0.05)

Infection and inflammatory responses were further assessed by immunofluorescence staining of bacteria (Fig.  8 c1-c6), TNF-α (Fig.  8 d1-d6), and IL-1β (Fig.  8 e1-e6). Both the Blank and PH groups showed strong positive staining, while the 0.5CuHP/PH group displayed weak positive staining. Quantitative analysis of bacteria (Fig.  8 g), TNF-α (Fig.  8 h), and IL-1β (Fig.  8 i) further confirmed the results.

The tracheal mucosa is highly vulnerable to injury from inhaled debris, including dust and bacteria, as well as therapeutic procedures like endotracheal intubation, tracheostomy, and excessive endotracheal tube expansion. The susceptibility to injury has significantly increased following the outbreak of coronavirus disease 2019 [ 2 ]. However, the lack of timely and effective treatments has resulted in severe tracheal infections, cartilage damage, and subsequent complications such as softening, stenosis, necrosis, and respiratory diseases [ 3 ]. In this study, we for the first time introduced a novel biomaterial-based approach to address this issue by utilizing an injected tissue-adhesive CuHP/PH hydrogel.

The design of the material was guided by several considerations. Firstly, the trachea, being a flexible, tubular organ with a vital role in inhalation and exhalation, necessitates the hydrogel to exhibit excellent tissue-adhesive properties for effective integration and support at the application site, considering the airflow dynamics in the central airway [ 32 ]. Secondly, the epithelial tissue layer acts as a physical barrier to resist bacteria and debris effectively. It also facilitates the removal of foreign particles through the secretion of mucus from goblet cells and the directional movement of ciliated cells [ 33 ]. Thirdly, the submucosal layer, rich in microvessels, can provide adequate nutritional support for mucosal tissue regeneration [ 34 ]. In cases of tracheal mucosal and microvessels injuries, bacteria colonizing the injury site can easily cause infection and cartilage deterioration. Moreover, when the wound repair response goes out of control, fibroblasts are stimulated by transforming growth factor-β1 to transform into myofibroblasts, initiating collagen I and III deposition and wound contraction, resulting in hyperplasia of granulation and scar formation [ 35 ]. In the current study, we found that CuHP/PH hydrogel possesses multifunctional biological effects like tissue adhesion, angiogenesis, and antibacterial properties.

Adhesive hydrogel are gaining traction as attractive materials in tissue engineering applications due to their favorable characteristics, including a customizable structure, intrinsic flexibility, outstanding biocompatibility, closely resembling physiological conditions, dynamic mechanical strength, and notably appealing self-adhesive properties [ 36 ]. However, conventional hydrogel usually exhibit limited adhesive strength toward wet and dynamic biological tissues due to the abundance of water in hydrogel matrices and the complexity of tissue environments [ 37 ]. Various unique and versatile strategies have been developed to produce preferred adhesive hydrogel. Wang et al. designed an adhesive hydrogel inspired by mussels; and yet mussel-inspired hydrogel suffer from poor mechanical properties, significantly limiting their practical applications [ 38 ]. Adhesive hydrogel based on supramolecular strategies have been reported for their dynamic microenvironment characteristics and superior mechanical strength. However, many unaddressed challenges, such as biocompatibility, byproduct generation, degradation cycle, and injectable abilities, limit their application [ 39 ]. Our previous study had confirmed that PH hydrogel displayed unique biocompatibility, mechanical and injectable properties. Moreover, the free amino side chains of lysine residues on the surface of albumin can react with modified PEG-PEG [PEG-(SS) 2 ] to form amide bonds, which results in the formation of albumin hydrogels. Besides, the active succinimide ester of the PH hydrogel can react with the amino group on the tissue’s surface, endowing the hydrogel with excellent tissue adhesion [ 17 , 18 ]. Additionally, our results demonstrated PH hydrogel’s gelling time is approximately 10 min, satisfying the requirement for a readiness period before using injectable hydrogel in various circumstances. Moreover, PH hydrogel demonstrate exceptional biocompatibility and an appropriate degradation rate (1 ~ 2 weeks), positioning them as potential candidates for treating tracheal mucosal injuries. Nevertheless, our results revealed pure PH hydrogel promotes bacterial growth and biofilm formation, making it unfavorable for application in a contaminated environment.

The presence of a persistent microbial environment makes tracheal injuries highly susceptible to infection, resulting in cartilage deterioration and potential complications [ 40 ]. A prompt and effective antibacterial strategy might significantly promote efficient wound healing. Antibiotic therapy is the conventional method against bacterial infections, but antibiotic abuse has led to bacterial drug resistance [ 41 ]. Recently, nanomaterials have garnered widespread attention for their antibacterial properties. Ag nanoparticles have been adopted to effectively resist infection through concentration-dependent antimicrobial activity [ 42 ]. Besides, some researchers have fabricated MoS2-PDA nanozyme composite hydrogel with antibacterial ability [ 43 ]; However, these nanomaterials have unsettled issues such as high manufacturing costs or insufficient antibacterial efficiency. In the current study, CuHP/PH hydrogel were prepared through a simple physical mixing method. Our results showed that CuHP nanosheets displayed POD-like catalytic activity, and CuHP/PH hydrogel exhibited excellent bactericidal and biofilm destruction abilities, which could be achieved through the following mechanisms: modulation of bacterial membrane permeability, disruption of RNA and DNA replication by generating reactive oxygen species at the bacterial surface, and inducing evident genetic toxicity in bacteria [ 44 ].

Cu containing biomaterials can not only decrease the incidence of infections but also improve tissue regeneration and wound healing by promoting the formation of a new vascular network. Compared with protein therapeutics, gene and nucleic acid-based therapies, and stem cell-based therapies, Cu ions have garnered attention for their potential as angiogenic promoters due to their excellent biocompatibility, cost-effectiveness, and versatility [ 45 ]. Additionally, we substantiated the potential of CuHP/PH hydrogel to enhance the in vitro proliferative, migratory, and tube formation capacities, as well as the secretion of angiogenesis-related factors by HUVECs, such as VEGF , HIF-α , eNOS and FGF2 . And we further verified the favorable vessel formation with CuHP/PH hydrogel in vivo circumstance. We speculated that (1) Cu ions released from CuHP/PH hydrogel might stimulate endothelial cell proliferation during wound healing by upregulating related gene expression [ 46 ]; (2) CuHP/PH hydrogel showed more controllable and sustained release of Cu ions leading to enhanced blood vessel formation and optimizing wound healing in vivo circumstance.

Our previous studies have demonstrated that the lack of tracheal mucosa is a major obstacle in the reconstruction of tissue-engineered trachea [ 4 , 5 , 6 , 7 ]. This study further demonstrated that the destruction of tracheal mucosa would lead to severe infection, tracheal stenosis, and cartilage destruction, consistent with our previous studies. Current strategies for clinical tracheal mucosal injury primarily include two main components: (1) Conservative treatment consisting of antibiotics, endotracheal tube or bronchoscopic surveillance; (2) Surgical treatment is adopted when conservative treatment fails [ 47 ]. However, these treatments are often applied when severe ventilation dysfunction is present.

In this study, we developed a CuHP/PH hydrogel for the early-stage treatment of injured tracheal mucosa. Our results demonstrate that the CuHP/PH hydrogel effectively promotes mucosal regeneration, significantly improves the survival rate of experimental animals, and mitigates tracheal stenosis induced by granulation tissue hyperplasia resulting from potential infection and inflammation. It is noteworthy that we observed a significant reduction in tracheal cartilage deterioration in the CuHP/PH hydrogel group. And cartilage deterioration has consistently been identified as a primary cause of tracheomalacia and narrowing in clinical settings [ 48 ]. It is also a pressing challenge that needs to be addressed in the field of tissue-engineered tracheal cartilage regeneration [ 49 ]. This study further substantiated the paramount importance of effective antibacterial, angiogenesis, and epithelial regeneration measures for tracheal cartilage growth. Several factors might contribute to the observed outcomes: (1) The antibacterial properties of CuHP released from CuHP/PH hydrogel effectively inhibited early-stage mucosal injury and related complications arising from infection; (2) Furthermore, CuHP released from CuHP/PH hydrogel significantly enhanced angiogenesis, thereby promoting mucosal regeneration; (3) Moreover, CuHP/PH hydrogel may function as a physical barrier, protecting tracheal cartilage from bacterial invasion and establishing a conducive microenvironment for mucosal regeneration.

Although the current study yielded relative success after applying CuHP/PH hydrogel to deal with tracheal mucosa injuries. Several limitations still need to be addressed in the future: (1) Further evaluation is warranted to assess the degradation behavior of CuHP/PH hydrogel within the airway, including its potential to enter lung tissue with the airflow, be excreted from the body, or become absorbed by adjacent tissues and subsequently enter the bloodstream; (2) The mechanism behind infection and inflammation on tracheal mucosal injury and regeneration is still worth further discussion; (3) Future studies should focus on the application of CuHP/PH hydrogel in clinic and tissue engineering tracheal cartilage.

In this study, we engineered a CuHP/PH hydrogel via injection, demonstrating remarkable properties in terms of tissue adhesion, angiogenesis, and antibacterial activities. This composite hydrogel, as fabricated, allows for facile delivery to the damaged region of the rabbit tracheal mucosa using a non-invasive method. Within a minimal timeframe, the hydrogel adheres tightly to the mucosa, stimulating mucosal restoration and substantially decreasing the occurrence of complications, such as infection, tracheal stenosis, and cartilage deterioration. Anticipated outcomes of our study include the introduction of a novel strategy for the remediation of tracheal mucosal injuries and potentially, other tracheal diseases.

Data availability

All data used to generate these results are available in the main text and supporting information.

Lei D, Luo B, Guo YF, Wang D, Yang H, Wang SF, Xuan HX, Shen A, Zhang Y, Liu ZH, He CL, Qing FL, Xu Y, Zhou GD. You, 4-Axis printing microfibrous tubular scaffold and tracheal cartilage application. Sci China Mater. 2019;62(12):1910–20.

Article   CAS   Google Scholar  

Jahshan F, Ertracht O, Eisenbach N, Daoud A, Sela E, Atar S, Abu Ammar A, Gruber M. A novel rat model for tracheal mucosal damage assessment of following long term intubation. Int J Pediatr Otorhinolaryngol. 2020;128:109738.

Article   CAS   PubMed   Google Scholar  

Deshmukh A, Jadhav S, Wadgoankar V, Takalkar U, Deshmukh H, Apsingkar P, Sonwatikar P, Antony P. Airway Management and Bronchoscopic Treatment of Subglottic and Tracheal Stenosis using Holmium laser with balloon dilatation. Indian J Otolaryngol Head Neck Surg. 2019;71(Suppl 1):453–8.

Article   PubMed   Google Scholar  

Gao W, Chen K, He W, Zhao S, Cui D, Tao C, Xu Y, Xiao X, Feng Q, Xia H. Synergistic chondrogenesis promotion and arthroscopic articular cartilage restoration via injectable dual-drug-loaded sulfated hyaluronic acid hydrogel for stem cell therapy. Compos Part B: Eng 263 (2023).

Xu Y, Dai J, Zhu XS, Cao RF, Song N, Liu M, Liu XG, Zhu JJ, Pan F, Qin LL, Jiang GN, Wang HF, Yang Y. Biomimetic Trachea Engineering via a modular Ring Strategy based on bone-marrow stem cells and Atelocollagen for use in extensive Tracheal Reconstruction. Adv Mater 34(6) (2022).

Xu Y, Duan L, Li Y, She Y, Zhu J, Zhou G, Jiang G, Yang Y. Nanofibrillar Decellularized Wharton’s Jelly Matrix for Segmental Tracheal Repair. Adv Funct Mater. 2020;30(14):1910067.

Xu Y, Guo Y, Li Y, Huo Y, She Y, Li H, Jia Z, Jiang G, Zhou G, You Z, Duan L. Biomimetic Trachea regeneration using a modular Ring Strategy based on poly(Sebacoyl Diglyceride)/Polycaprolactone for segmental Trachea defect repair. Adv Funct Mater. 2020;30(42):2004276.

Piazza C, Filauro M, Dikkers FG, Nouraei SAR, Sandu K, Sittel C, Amin MR, Campos G, Eckel HE, Peretti G. Long-term intubation and high rate of tracheostomy in COVID-19 patients might determine an unprecedented increase of airway stenoses: a call to action from the European Laryngological Society. Eur Arch Oto-Rhino-L. 2021;278(1):1–7.

Article   Google Scholar  

Liu NB, Zhu SJ, Deng YZ, Xie M, Zhao MY, Sun TC, Yu CJ, Zhong Y, Guo R, Cheng KL, Chang DH, Zhu P. Construction of multifunctional hydrogel with metal-polyphenol capsules for infected full-thickness skin wound healing. Bioact Mater. 2023;24:69–80.

CAS   PubMed   Google Scholar  

Zhang HM, Guo M, Zhu TH, Xiong H, Zhu LM. A careob-like nanofibers with a sustained drug release profile for promoting skin wound repair and inhibiting hypertrophic scar. Compos Part B-Eng 236 (2022).

Zhang Y, Xu K, Zhi D, Qian M, Liu K, Shuai Q, Qin Z, Xie J, Wang K, Yang J. Improving vascular regeneration performance of Electrospun Poly(ε-Caprolactone) vascular grafts via synergistic functionalization with VE-Cadherin/VEGF. Adv Fiber Mater. 2022;4(6):1685–702.

Zhi D, Cheng Q, Midgley AC, Zhang Q, Wei T, Li Y, Wang T, Ma T, Rafique M, Xia S, Cao Y, Li Y, Li J, Che Y, Zhu M, Wang K, Kong D. Mechanically reinforced biotubes for arterial replacement and arteriovenous grafting inspired by architectural engineering. Sci Adv. 2022;8(11):eabl3888.

Article   CAS   PubMed   PubMed Central   Google Scholar  

Xu Y, Wang Z, Hua Y, Zhu X, Wang Y, Duan L, Zhu L, Jiang G, Xia H, She Y, Zhou G. Photocrosslinked natural hydrogel composed of hyaluronic acid and gelatin enhances cartilage regeneration of decellularized trachea matrix. Mater Sci Eng C Mater Biol Appl. 2021;120:111628.

Wilson NM, Norton A, Young FP, Collins DW. Airborne transmission of severe acute respiratory syndrome coronavirus-2 to healthcare workers: a narrative review. Anaesthesia. 2020;75(8):1086–95.

Zhang Y, Li X, Zhang Z, Li H, Chen D, Jiao Y, Fan C, Zeng Z, Chang J, Xu Y, Peng B, Yang C, Que Y. Zn(2) SiO(4) Bioceramic attenuates Cardiac Remodeling after myocardial infarction. Adv Healthc Mater. 2023;12(21):e2203365.

Zhao X, Si J, Huang D, Li K, Xin Y, Sui M. Application of star poly(ethylene glycol) derivatives in drug delivery and controlled release. J Control Release. 2020;323:565–77.

Xing M, Jiang Y, Bi W, Gao L, Zhou Y-L, Rao S-L, Ma L-L, Zhang Z-W, Yang H-T, Chang J. Strontium ions protect hearts against myocardial ischemia/reperfusion injury. Sci Adv 7(3) eabe0726.

Zhang Y, Li X, Zhang Z, Li H, Chen D, Jiao Y, Fan C, Zeng Z, Chang J, Xu Y, Peng B, Yang C, Que Y. Zn2SiO4 Bioceramic attenuates Cardiac Remodeling after myocardial infarction. Adv Healthc Mater. 2023;12(21):2203365.

Kong FH, Mehwish N, Lee BH. Emerging albumin hydrogels as personalized biomaterials. Acta Biomater. 2023;157:67–90.

Kharaziha M, Baidya A, Annabi N. Rational design of Immunomodulatory Hydrogels for Chronic Wound Healing. Adv Mater. 2021;33(39):2100176.

Zhang QY, Yan ZB, Meng YM, Hong XY, Shao G, Ma JJ, Cheng XR, Liu J, Kang J, Fu CY. Antimicrobial peptides: mechanism of action, activity and clinical potential. Mil Med Res. 2021;8(1):48.

CAS   PubMed   PubMed Central   Google Scholar  

Sun Y-H, Reid B, Fontaine JH, Miller LA, Hyde DM, Mogilner A, Zhao M. Airway epithelial wounds in rhesus monkey generate ionic currents that guide cell migration to promote healing. J Appl Physiol. 2011;111(4):1031–41.

Qiu Y, Tian J, Kong S, Feng Y, Lu Y, Su L, Cai Y, Li M, Chang J, Yang C, Wei X. SrCuSi(4) O(10) /GelMA composite hydrogel-mediated vital pulp therapy: integrating Antibacterial Property and enhanced pulp regeneration activity. Adv Healthc Mater. 2023;12(24):e2300546.

Xu Q, Jiang F, Guo G, Wang E, Younis MR, Zhang Z, Zhang F, Huan Z, Fan C, Yang C, Shen H, Chang J. Targeted hot ion therapy of infected wound by glycol chitosan and polydopamine grafted Cu-SiO2 nanoparticles. Nano Today. 2021;41:101330.

Dong C, Yang C, Younis MR, Zhang J, He G, Qiu X, Fu LH, Zhang DY, Wang H, Hong W, Lin J, Wu X, Huang P. Bioactive NIR-II light-responsive shape memory composite based on Cuprorivaite Nanosheets for Endometrial Regeneration. Adv Sci (Weinh). 2022;9(12):e2102220.

Rafique M, Wei T, Sun Q, Midgley AC, Huang Z, Wang T, Shafiq M, Zhi D, Si J, Yan H, Kong D, Wang K. The effect of hypoxia-mimicking responses on improving the regeneration of artificial vascular grafts. Biomaterials. 2021;271:120746.

Huang Z, Zhang Y, Liu R, Li Y, Rafique M, Midgley AC, Wan Y, Yan H, Si J, Wang T, Chen C, Wang P, Shafiq M, Li J, Zhao L, Kong D, Wang K. Cobalt loaded electrospun poly(epsilon-caprolactone) grafts promote antibacterial activity and vascular regeneration in a diabetic rat model. Biomaterials. 2022;291:121901.

Yan H, Cheng Q, Si J, Wang S, Wan Y, Kong X, Wang T, Zheng W, Rafique M, Li X, He J, Midgley AC, Zhu Y, Wang K, Kong D. Functionalization of in vivo tissue-engineered living biotubes enhance patency and endothelization without the requirement of systemic anticoagulant administration. Bioact Mater. 2023;26:292–305.

Lv Y, Cai F, He Y, Li L, Huang Y, Yang J, Zheng Y, Shi X. Multi-crosslinked hydrogels with strong wet adhesion, self-healing, antibacterial property, reactive oxygen species scavenging activity, and on-demand removability for seawater-immersed wound healing. Acta Biomater. 2023;159:95–110.

Safronova EI, Dydykin SS, Grigorevskiy ED, Tverye EA, Kolchenko SI, Piskunova NN, Denisova AV, Titova GP, Parshin VD, Romanova OA, Panteleyev AA. Experimental animal model for assessment of tracheal epithelium regeneration. Laryngoscope. 2019;129(6):E213–9.

Gao E, Wang P, Chen F, Xu Y, Wang Q, Chen H, Jiang G, Zhou G, Li D, Liu Y, Duan L. Skin-derived epithelial lining facilitates orthotopic tracheal transplantation by protecting the tracheal cartilage and inhibiting granulation hyperplasia. Biomaterials Adv. 2022;139:213037.

Gao ER, Wang Y, Wang PL, Wang QY, Wei YX, Song DY, Xu HF, Ding JH, Xu Y, Xia HT, Chen R, Duan L. C-Shaped Cartilage Development Using Wharton’s Jelly-Derived Hydrogels to Assemble a Highly Biomimetic Neotrachea for use in Circumferential Tracheal Reconstruction. Adv Funct Mater 33(14) (2023).

Dikina AD, Strobel HA, Lai BP, Rolle MW, Alsberg E. Engineered cartilaginous tubes for tracheal tissue replacement via self-assembly and fusion of human mesenchymal stem cell constructs. Biomaterials. 2015;52:452–62.

Furlow PW, Mathisen DJ. Surgical anatomy of the trachea. Ann Cardiothorac Sur. 2018;7(2):255–60.

Fan Y, Li X, Fang X, Liu Y, Zhao S, Yu Z, Tang Y, Wu P. Antifibrotic role of Nintedanib in Tracheal Stenosis after a Tracheal Wound. Laryngoscope. 2021;131(9):E2496–505.

Zhao Y, Song S, Ren X, Zhang J, Lin Q, Zhao Y. Supramolecular Adhesive Hydrogels Tissue Eng Appl Chem Rev. 2022;122(6):5604–40.

CAS   Google Scholar  

Yang J, Bai R, Chen B, Suo Z. Hydrogel Adhesion: a Supramolecular Synergy of Chemistry, Topology, and mechanics. Adv Funct Mater. 2020;30(2):1901693.

Zhang C, Wu B, Zhou Y, Zhou F, Liu W, Wang Z. Mussel-inspired hydrogels: from design principles to promising applications. Chem Soc Rev. 2020;49(11):3605–37.

Zhang YS, Khademhosseini A. Advances in engineering hydrogels. Science 356(6337) (2017).

Jungebluth P, Moll G, Baiguera S, Macchiarini P. Tissue-engineered airway: a regenerative solution. Clin Pharmacol Ther. 2012;91(1):81–93.

Wang CF, Luo Y, Liu XM, Cui ZD, Zheng YF, Liang YQ, Li ZY, Zhu SL, Lei J, Feng XB, Wu SL. The enhanced photocatalytic sterilization of MOF-Based nanohybrid for rapid and portable therapy of bacteria-infected open wounds. Bioact Mater. 2022;13:200–11.

PubMed   Google Scholar  

Rahman L, Sarwar Y, Khaliq S, Inayatullah W, Abbas A, Mobeen A, Ullah SZ, Hussain WS, Khan ME, Kyriazi I, Hussain AG, Kanaras A, Rehman. Surfactin-conjugated silver nanoparticles as an antibacterial and Antibiofilm Agent against. Acs Appl Mater Inter. 2023;15(37):43321–31.

Li Y, Yu P, Wen J, Sun H, Wang D, Liu J, Li J, Chu H. Nanozyme-based stretchable hydrogel of low hysteresis with antibacterial and antioxidant dual functions for closely fitting and Wound Healing in Movable Parts. Adv Funct Mater. 2022;32(13):2110720.

Liu W, Li J, Cheng M, Wang Q, Qian Y, Yeung KWK, Chu PK, Zhang X. A surface-engineered polyetheretherketone biomaterial implant with direct and immunoregulatory antibacterial activity against methicillin-resistant Staphylococcus aureus. Biomaterials. 2019;208:8–20.

Veith AP, Henderson K, Spencer A, Sligar AD, Baker AB. Therapeutic strategies for enhancing angiogenesis in wound healing. Adv Drug Deliv Rev. 2019;146:97–125.

Wang YF, Zhang W, Yao QQ. Copper-based biomaterials for bone and cartilage tissue engineering. J Orthop Transl. 2021;29:60–71.

Google Scholar  

Zhao Z, Zhang T, Yin X, Zhao J, Li X, Zhou Y. Update on the diagnosis and treatment of tracheal and bronchial injury. J Thorac Dis. 2017;9(1):E50–6.

Article   PubMed   PubMed Central   Google Scholar  

Parpucu UM, Aydemir S. Our clinical experience with patients requiring Intensive Care for Tracheal stenosis: a retrospective case-control study. Cureus. 2023;15(9):e45978.

PubMed   PubMed Central   Google Scholar  

Wang P, Wang T, Xu Y, Song N, Zhang X. 3D-bioprinted cell-laden hydrogel with anti-inflammatory and anti-bacterial activities for tracheal cartilage regeneration and restoration. IJB 0(0) (2023).

Download references

The research was supported by the National Natural Science Foundation of China (82302395, 32271386), the Natural Science Foundation of Shanghai (22ZR1452100, 22YF1437400), the Young Elite Scientists Sponsorship Program by CAST (2023QNRC001), the Wenzhou Science and Technology Project (Y20220142), Wenzhou Science and Technology Major Project (ZY2022028), and the seed grants from the Wenzhou Institute, University of Chinese Academy of Sciences (WIUCASQD2020013, WIUCASQD2021030).

Author information

Pengli Wang, Erji Gao and Tao Wang contributed equally to this work.

Authors and Affiliations

Department of Thoracic Surgery, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai, 200433, China

Pengli Wang, Erji Gao, Tao Wang, Yong Xu, Zheng Ci & Liang Duan

Joint Centre of Translational Medicine, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, 325000, China

Yanping Feng, Lefeng Su, Jiang Chang & Chen Yang

Department of Plastic and Reconstructive Surgery, Shanghai 9th People’s Hospital, Shanghai Key Laboratory of Tissue Engineering, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China

Pengli Wang, Wei Gao & Zheng Ci

Zhejiang Engineering Research Center for Tissue Repair Materials, Wenzhou Institute, University of Chinese Academy of Sciences, Wenzhou, 325000, China

Pengli Wang, Yanping Feng, Lefeng Su, Jiang Chang & Chen Yang

Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, CA, 90095, USA

Muhammad Rizwan Younis

You can also search for this author in PubMed   Google Scholar

Contributions

Pengli Wang, Erji Gao, and Tao Wang designed experiments and wrote the manuscript. Pengli Wang, Erji Gao, Tao Wang, Yanping Feng, Yong Xu, Lefeng Su, Wei Gao, Zheng Ci, and Muhammad Rizwan Younis conducted all experiments and related analysis. Jiang Chang, Chen Yang, and Liang Duan revised the manuscript and supervised this study.

Corresponding authors

Correspondence to Jiang Chang , Chen Yang or Liang Duan .

Ethics declarations

Ethics approval and consent to participate.

This study received approval from the Ethics Committee of Shanghai Pulmonary Hospital, Shanghai, China (K19-080Y).

Consent for publication

All authors have approved the manuscript and agree for the submission.

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note.

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

Electronic supplementary material

Below is the link to the electronic supplementary material.

Supplementary Material 1

Supplementary Material 2

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, 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 you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. 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-nc-nd/4.0/ .

Reprints and permissions

About this article

Cite this article.

Wang, P., Gao, E., Wang, T. et al. Copper hydrogen phosphate nanosheets functionalized hydrogel with tissue adhesive, antibacterial, and angiogenic capabilities for tracheal mucosal regeneration. J Nanobiotechnol 22 , 652 (2024). https://doi.org/10.1186/s12951-024-02920-8

Download citation

Received : 31 October 2023

Accepted : 10 October 2024

Published : 23 October 2024

DOI : https://doi.org/10.1186/s12951-024-02920-8

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

• Tracheal mucosa repair
• Copper hydrogen phosphate nanosheets, Hydrogel
• Antibacteria
• Angiogenesis

Journal of Nanobiotechnology

ISSN: 1477-3155

• Submission enquiries: [email protected]

Enhancing quasi solid-state dye-sensitized solar cell performance using mixed-polymer gel electrolytes: the influence of low and high molar weight polymers

• Research Article
• Published: 24 October 2024

Cite this article

• T. M. W. J. Bandara 1 ,
• R. D. M. A. C. B. Rajakarunarathne 1 ,
• H. M. N. Wickramasinghe 1 ,
• L. Ajith DeSilva 2 ,
• R. P. Chandrika 1 &
• S. N. F. Yusuf 3  

Explore all metrics

Gel polymer electrolytes (GPEs) are crucial in quasi-solid-state dye-sensitized solar cells (DSSCs) due to their chemical and physical stability, enhanced safety, and improved performance, which boosts ionic conductivity. This study presents the enhancing gel polymer electrolyte properties intended for DSSCs by blending low and high molar weight variants of the same polymer. The hot press method was used to synthesize the polymer blend electrolyte, the resulting in electrolyte gave a notable improvement in DSSC performance. The blend incorporates polyethylene oxide (PEO, MW 4,000,000) and its lower molar weight counterpart, polyethylene glycol (PEG, MW 4000). The ionic conductivities of the GPEs were assessed via impedance analysis. The GPE with 100% PEG achieved the highest ionic conductivity (10.30 mS cm −1 ) but was liquid-like, while 100% PEO showed the lowest conductivity (5.23 mS cm −1 ) with a solid-state nature. A blend with a 3:1 PEO-to-PEG ratio exhibited intermediate conductivity and a gel-like consistency. The electrolyte having molar composition PEO (7.5) PEG (2.5) EC (40) PC (40) Hex 4 NI (0.8) LiI (1.2) I 2(0.2) in DSSC yielded an extremely high 8.76% power conversion efficiency and a short-circuit current density of 13.80 mA cm −2 . This electrolyte exhibited ionic conductivity of 6.86 mS cm −1 30 °C. The lowest efficiency was observed for the 100% PEO content. The study demonstrated a significant efficiency improvement of 38.17% and 36.45% in blend polymer electrolyte-based DSSCs compared to single polymer electrolytes with PEO and PEG, respectively. Conductivity in the GPEs followed Vogel–Tamman–Fulcher behavior. The DSSCs utilized N719 dye-sensitized TiO 2 nanoparticle multilayer photoanodes and Pt counter electrodes. The results indicate that combining low and high molar weight polymers in the electrolyte significantly boosts DSSC efficiency. Current efforts aim to refine polymer composition and understand the mechanisms behind the efficiency enhancement in mixed-phase gel polymer electrolytes.

Graphical Abstract

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

Similar content being viewed by others

Impact of Diethyl carbonate in PVA based gel polymer electrolytes on dye-sensitized solar cells performance

Enhancing efficiency of dye sensitized solar cells based on poly(propylene) carbonate polymer gel electrolytes incorporating double salts

Enhanced efficiency in dye-sensitized solar cell based on zinc oxide-modified poly(ethylene oxide) gel electrolyte, explore related subjects, data availability.

Data will be made available on request.

O’Regan B, Grätzel M (1991) A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO 2 films. Nature 353(6346):737–740

Article   CAS   Google Scholar  

Mustafa MN, Sulaiman Y (2021) Review on the effect of compact layers and light scattering layers on the enhancement of dye-sensitized solar cells. Sol Energy 215:26–43

Nishshanke GBMMM, Thilakarathna BDKK, Albinsson I, Mellander BE, Bandara TMWJ (2021) Multi-layers of TiO 2 nanoparticles in the photoelectrode and binary iodides in the gel polymer electrolyte based on poly(ethylene oxide) to improve quasi solid-state dye-sensitized solar cells. J Solid State Electrochem 25:707–720

Bandara TMWJ, Gunathilake SMS, Nishshanke GBMMM, Dissanayake MAKL, Chaure NB, Olusola OI et al (2023) Efficiency enhancement and chrono-photoelectron generation in dye-sensitized solar cells based on spin-coated TiO 2 nanoparticle multilayer photoanodes and a ternary iodide gel polymer electrolyte. J Mater Sci Mater Electron 34(28):1969

Cho YG, Hwang C, Cheong DS, Kim YS, Song HK (2019) Gel/solid polymer electrolytes characterized by in situ gelation or polymerization for electrochemical energy systems. Adv Mater 31(20):1804909

Article   Google Scholar  

Mahmood A (2015) Recent research progress on quasi-solid-state electrolytes for dye-sensitized solar cells. J Energy Chem 24(6):686–692

Jiang N, Sumitomo T, Lee T (2013) High temperature stability of dye solar cells. Sol Energy Mater Sol Cells 119:36–50

Rani MSA, Abdullah NA, Sainorudin MH, Mohammad M, Ibrahim S (2021) The development of poly(ethylene oxide) reinforced with a nanocellulose-based nanocomposite polymer electrolyte in dye-sensitized solar cells. Mater Adv 2(16):5465–5470

Dotter M, Storck JL, Surjawidjaja M, Adabra S, Grothe T (2021) Investigation of the long-term stability of different polymers and their blends with PEO to produce gel polymer electrolytes for non-toxic dye-sensitized solar cells. Appl Sci 11(13):5834

Abdollahi S, Sadadi H, Ehsani M, Aram E (2021) Highly efficient polymer electrolyte based on electrospun PEO/PAN/single-layered graphene oxide. Ionics 27(8):3477–3487

Venkatesan S, Liu IP, Lin JC, Tsai MH, Teng H, Lee YL (2018) Highly efficient quasi-solid-state dye-sensitized solar cells using polyethylene oxide (PEO) and poly(methyl methacrylate) (PMMA)-based printable electrolytes. J Mater Chem A 6(21):10085–10094

Bandara TMWJ, Wickramasinghe HMN, Wijayaratne K, DeSilva LA, Perera AAI (2021) Quasi-solid-state dye-sensitized solar cells utilizing TiO 2 /graphite composite counter electrode and TiO 2 /N719 sensitizer photoelectrode for low-cost power generation. J Mater Sci Mater Electron 32:26758–26769

Dissanayake MAKL, Ekanayake EMBS, Bandara LRAK, Seneviratne VA, Thotawatthage CA, Jayaratne SL, Senadeera GKR (2016) Efficiency enhancement by mixed cation effect in polyethylene oxide (PEO)-based dye-sensitized solar cells. J Solid State Electrochem 20:193–201

Bandara TMWJ, Nishshanke GBMMM, Thilakarathna BDKK (2019) Binary iodides and polyethylene oxide (PEO) based gel polymer electrolyte for dye sensitized solar cells. Mod Approaches Mater Sci 2:182–185

Google Scholar  

Singh PK, Nagarale RK, Pandey SP, Rhee HW, Bhattacharya B (2011) Present status of solid state photoelectrochemical solar cells and dye sensitized solar cells using PEO-based polymer electrolytes. Adv Nat Sci Nanosci Nanotechnol 2(2):023002

Bandara TMWJ, Mellander BE, Albinsson I, Dissanayake MAKL (2009) Effect of thermal history and characterization of plasticized, composite polymer electrolyte based on PEO and tetrapropylammonium iodide salt (Pr4N+I−). Solid State Ion 180(4–5):362–367

Nishshanke GBMMM, Arof AK, Bandara TMWJ (2020) Review on mixed cation effect in gel polymer electrolytes for quasi solid-state dye-sensitized solar cells. Ionics 26(8):3685–3704

Evan MSH, Uddin MJ, Tulin WS, Islam MS, Rockshat M, Khandaker MU, Rahman IMM, Chowdhury FI (2023) Polyethylene oxide-based nanocomposites as polymer electrolytes for dye-sensitized solar cell application. ECS J Solid State Sci Technol 12(11):115004

Shi Y, Zhan C, Wang L, Ma B, Gao R, Zhu Y, Qiu Y (2009) The electrically conductive function of high-molecular weight poly(ethylene oxide) in polymer gel electrolytes used for dye-sensitized solar cells. Phys Chem Chem Phys 11(21):4230–4235

Article   CAS   PubMed   Google Scholar  

Pavithra N, Velayutham D, Sorrentino A, Anandan S (2017) Poly(ethylene oxide) polymer matrix coupled with urea as gel electrolyte for dye sensitized solar cell applications. Synth Met 226:62–70

Pavithra N, Velayutham D, Sorrentino A, Anandan S (2017) Thiourea incorporated poly(ethylene oxide) as transparent gel polymer electrolyte for dye sensitized solar cell applications. J Power Sources 353:245–253

Dissanayake MAKL, Kumari JMKW, Senadeera GKR, Jaseetharan T, Mellander BE, Albinsson I, Furlani M (2020) Polyaniline (PANI) mediated cation trapping effect on ionic conductivity enhancement in poly(ethylene oxide) based solid polymer electrolytes with application in solid state dye sensitized solar cells. React Funct Polym 155:104683

Kumari JMKW, Senadeera GKR, Weerasinghe AMJS, Thotawatthage CA, Dissanayake MAKL (2021) Effect of polyaniline (PANI) on efficiency enhancement of dye-sensitized solar cells fabricated with poly(ethylene oxide)-based gel polymer electrolytes. J Solid State Electrochem 25:695–705

Teo LP, Tiong TS, Buraidah MH, Arof AK (2018) Effect of lithium iodide on the performance of dye sensitized solar cells (DSSC) using poly(ethylene oxide) (PEO)/poly(vinyl alcohol) (PVA) based gel polymer electrolytes. Opt Mater 85:531–537

Chawla P, Trivedi S, Pooja K (2023) Investigation on various polymer electrolytes for development of dye sensitized solar cell. In: Materials science: a field of diverse industrial applications. Bentham Science, Sharjah, p 158

Akhtar MS, Kwon S, Stadler FJ, Yang OB (2013) High efficiency solid state dye sensitized solar cells with graphene–polyethylene oxide composite electrolytes. Nanoscale 5(12):5403–5411

Khannam M, Dolui SK (2017) Cerium doped TiO 2 photoanode for an efficient quasi-solid state dye sensitized solar cells based on polyethylene oxide/multiwalled carbon nanotube/polyaniline gel electrolyte. Sol Energy 150:55–65

Prabakaran K, Jandas PJ, Mohanty S, Nayak SK (2018) Synthesis, characterization of reduced graphene oxide nanosheets and its reinforcement effect on polymer electrolyte for dye sensitized solar cell applications. Sol Energy 170:442–453

Aram E, Shaki H, Ehsani M (2023) Highly efficient and stable quasi-solid-state dye-sensitized solar cells with PEO/PMMA/single-layered graphene oxide composite electrolytes. Ionics 29(9):3743–3757

Zarrintaj P, Saeb MR, Jafari SH, Mozafari M (2020) Application of compatibilized polymer blends in biomedical fields. In: Compatibilization of polymer blends. Elsevier, Amsterdam, pp 511–537

Zhang D, Li L, Wu X, Wang J, Li Q, Pan K, He J (2021) Research progress and application of PEO-based solid state polymer composite electrolytes. Front Energy Res 9:726738

Johari SNAM, Tajuddin NA, Hanibah H, Deraman SK (2021) A review: ionic conductivity of solid polymer electrolyte based polyethylene oxide. Int J Electrochem Sci 16(10):211049

Lv N, Zhang Q, Xu Y, Li H, Wei Z, Tao Z et al (2023) PEO-based composite solid electrolyte for lithium battery with enhanced interface structure. J Alloys Compd 938:168675

Reddy MJ, Kumar JS, Rao US, Chu PP (2006) Structural and ionic conductivity of PEO blend PEG solid polymer electrolyte. Solid State Ion 177(3–4):253–256

Bhide A, Hariharan K (2007) Ionic transport studies on (PEO) 6 :NaPO 3 polymer electrolyte plasticized with PEG 400 . Eur Polym J 43(10):4253–4270

Das S, Ghosh A (2015) Effect of plasticizers on ionic conductivity and dielectric relaxation of PEO–LiClO 4 polymer electrolyte. Electrochim Acta 171:59–65

Abdullah OG, Ahmed HT, Tahir DA, Jamal GM, Mohamad AH (2021) Influence of PEG plasticizer content on the proton-conducting PEO:MC–NH 4 I blend polymer electrolytes based films. Results Phys 23:104073

Gupta S, Gupta AK, Pandey BK, Yadav RK (2022) Insight into structural, electronic, and chemical bonding properties of PEO–PEG–LiI polymer electrolyte: a first-principles investigation. Comput Theor Chem 1211:113667

Anantharaj G, Joseph J, Selvaraj M, Jeyakumar D (2015) Fabrication of stable dye sensitized solar cell with gel electrolytes using poly(ethylene oxide)–poly(ethylene glycol). Electrochim Acta 176:1403–1409

Venkatesan S, My NHT, Teng H, Lee YL (2023) Thin films of solid-state polymer electrolytes for dye-sensitized solar cells. J Power Sources 564:232896

Somsongkul V, Jamikorn S, Wongchaisuwat A, Thang SH, Arunchaiya M (2016) Efficiency and stability enhancement of quasi-solid-state dye-sensitized solar cells based on PEO composite polymer blend electrolytes. Adv Mater Res 1131:186–192

Aziz MF, Buraidah MH, Careem MA, Arof AK (2015) PVA based gel polymer electrolytes with mixed iodide salts (K + I − and Bu 4 N + I − ) for dye-sensitized solar cell application. Electrochim Acta 182:217–223

Bandara TMWJ, DeSilva LA, Ratnasekera JL, Hettiarachchi KH, Wijerathna AP, Thakurdesai M et al (2019) High efficiency dye-sensitized solar cell based on a novel gel polymer electrolyte containing RbI and tetrahexylammonium iodide (Hex 4 NI) salts and multi-layered photoelectrodes of TiO 2 nanoparticles. Renew Sustain Energy Rev 103:282–290

Vinoth S, Kanimozhi G, Narsimulu D, Kumar H, Srinadhu ES, Satyanarayana N (2020) Ionic relaxation of electrospun nanocomposite polymer-blend quasi-solid electrolyte for high photovoltaic performance of dye-sensitized solar cells. Mater Chem Phys 250:122945

Saidi NM, Farhana NK, Ramesh S, Ramesh K (2021) Influence of different concentrations of 4- tert -butyl-pyridine in a gel polymer electrolyte towards improved performance of dye-sensitized solar cells (DSSC). Sol Energy 216:111–119

Chalkias DA, Verykokkos NE, Kollia E, Petala A, Kostopoulos V, Papanicolaou GC (2021) High-efficiency quasi-solid state dye-sensitized solar cells using a polymer blend electrolyte with “polymer-in-salt” conduction characteristics. Sol Energy 222:35–47

De Angelis F, Mora-Sero I, Bai Y (2014) TiO 2 nanoparticles in dye-sensitized solar cells: a summary of recent progress. J Phys Chem Lett. 21 (4):1797–1808

Zhang J, Sivula K, Guijarro N, Prévot MS, Yu Z (2016) Solution-processed metal oxide thin film materials for transparent electrode applications in optoelectronic devices. Chem Soc Rev 45:118–151

Hauch A, Georg A (2001) Diffusion in the electrolyte and charge–transfer reaction at the platinum electrode in dye-sensitized solar cells. Electrochim Acta 46(22):3457–3466

Al-Alwani MA, Mohamad AB, Ludin NA, Kadhum AAH, Sopian K (2016) Dye-sensitised solar cells: development, structure, operation principles, electron kinetics, characterisation, synthesis materials and natural photosensitisers. Renew Sustain Energy Rev 65:183–213

Sundararajan V, Saidi NM, Ramesh S, Ramesh K, Selvaraj G, Wilfred CD (2019) Quasi solid-state dye-sensitized solar cell with P(MMA- co -MAA)-based polymer electrolytes. J Solid State Electrochem 23:1179–1189

Kim MR, Park SH, Kim JU, Lee JK (2011) Dye-sensitized solar cells based on polymer electrolytes, solar cells-dye-sensitized devices. In: Kosyachenko LA (ed) Solar cells. IntechOpen Limited, London

Seidalilir Z, Malekfar R, Wu HP, Shiu JW, Diau EWG (2015) High-performance and stable gel-state dye-sensitized solar cells using anodic TiO 2 nanotube arrays and polymer-based gel electrolytes. ACS Appl Mater Interfaces 7(23):12731–12739

Kang J, Wen J, Jayaram SH, Yu A, Wang X (2014) Development of an equivalent circuit model for electrochemical double layer capacitors (EDLCs) with distinct electrolytes. Electrochim Acta 115:587–598

Harrington DA, Van Den Driessche P (2011) Mechanism and equivalent circuits in electrochemical impedance spectroscopy. Electrochim Acta 56(23):8005–8013

Sarker S, Ahammad AS, Seo HW, Kim DM (2014) Electrochemical impedance spectra of dye-sensitized solar cells: fundamentals and spreadsheet calculation. Int J Photoenergy 2014(1):851705

Bisquert J, Zaban A, Greenshtein M, Mora-Seró I (2004) Determination of rate constants for charge transfer and the distribution of semiconductor and electrolyte electronic energy levels in dye-sensitized solar cells by open-circuit photovoltage decay method. J Am Chem Soc 126(41):13550–13559

Ri JH, Jin J, Xu J, Peng T, Ryu KI (2016) Preparation of iodine-free ionic liquid gel electrolyte using polyethylene oxide (PEO)–polyethylene glycol (PEG) and its application in Ti-foil-based dye-sensitized solar cells. Electrochim Acta 201:251–259

Kumari JMKW, Sanjeevadharshini N, Dissanayake MAKL, Senadeera GKR, Thotawatthage CA (2016) The effect of TiO 2 photo anode film thickness on photovoltaic properties of dye-sensitized solar cells. Ceylon J Sci 45(1):33

Bisquert J, Mora-Sero I (2010) Simulation of steady-state characteristics of dye-sensitized solar cells and the interpretation of the diffusion length. J Phys Chem Lett 1(1):450–456

Bisquert J, Fabregat-Santiago F, Mora-Sero I, Garcia-Belmonte G, Gimenez S (2009) Electron lifetime in dye-sensitized solar cells: theory and interpretation of measurements. J Phys Chem C 113(40):17278–17290

Chaurasia SK, Singh MP, Singh MK, Kumar P, Saroj AL (2022) Impact of ionic liquid incorporation on ionic transport and dielectric properties of PEO–lithium salt-based quasi-solid-state electrolytes: role of ion-pairing. J Mater Sci Mater Electron 33(3):1641–1656

Peng T, Fan K, Zhao D, Chen J (2010) Enhanced energy conversion efficiency of Mg 2+ -modified mesoporous TiO 2 nanoparticles electrodes for dye-sensitized solar cells. J Phys Chem C 114(50):22346–22351

Fan K, Zhang W, Peng T, Chen J, Yang F (2011) Application of TiO 2 fusiform nanorods for dye-sensitized solar cells with significantly improved efficiency. J Phys Chem C 115(34):17213–17219

Zeng Y, Huang Y, Liu N, Wang X, Zhang Y, Guo Y et al (2021) N-doped porous carbon nanofibers sheathed pumpkin-like Si/C composites as free-standing anodes for lithium-ion batteries. J Energy Chem 54:727–735

Almond DP, Duncan GK, West AR (1983) The determination of hopping rates and carrier concentrations in ionic conductors by a new analysis of AC conductivity. Solid State Ion 8(2):159–164

Download references

Acknowledgements

This work was supported by the Post-graduate Institute of Science, University of Peradeniya, Sri Lanka under the Research Grant No. PGIS/2020/05. Technical assistance from Dr. E. M. S. G. M. Edirisooriya, Department of Geology, and Mr. M.N.D. Ariyarathne, Department of Physics, University of Peradeniya, Sri Lanka is gratefully acknowledged.

Author information

Authors and affiliations.

Department of Physics and Postgraduate Institute of Science, University of Peradeniya, Peradeniya, Kandy, Sri Lanka

T. M. W. J. Bandara, R. D. M. A. C. B. Rajakarunarathne, H. M. N. Wickramasinghe & R. P. Chandrika

Department of Physics, University of West Georgia, Carrollton, USA

L. Ajith DeSilva

Chemistry Division, Centre for Foundation Studies in Science, University of Malaya, Kuala Lumpur, Malaysia

S. N. F. Yusuf

You can also search for this author in PubMed   Google Scholar

Contributions

TMWJB, Conceptualization, Methodology, Validation, Writing—Review and Editing, Investigation, Supervision, Funding acquisition. RDMACBR, Methodology, Data Curation, Visualization, Investigation, Writing—Original Draft. HMNW, Data Curation, Visualization, Investigation. LAD, Methodology, Validation, Writing—Review and Editing. RPC, Data Curation, Writing-Review and Editing. SNFY, Methodology, Validation, Writing—Review and Editing.

Corresponding author

Correspondence to T. M. W. J. Bandara .

Ethics declarations

Conflict of interest.

There is no conflict of interest. All authors involved in the work agree with the publication. All agencies that provided financial support are duly cited in the acknowledgments and are aware of the publications of the research results.

Additional information

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

Bandara, T.M.W.J., Rajakarunarathne, R.D.M.A.C.B., Wickramasinghe, H.M.N. et al. Enhancing quasi solid-state dye-sensitized solar cell performance using mixed-polymer gel electrolytes: the influence of low and high molar weight polymers. J Appl Electrochem (2024). https://doi.org/10.1007/s10800-024-02210-z

Download citation

Received : 23 June 2024

Accepted : 28 September 2024

Published : 24 October 2024

DOI : https://doi.org/10.1007/s10800-024-02210-z

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

• Dye-sensitized solar cells
• Polymer electrolyte
• Multilayer electrode
• Mixed polymer
• Efficiency enhancement
• Find a journal
• Publish with us
• Track your research