Exosomes are extracellular vesicles (EVs) secreted by different types of cells and have a size range of 30 nm to 150 nm. They have a significant role in intercellular communication as they transfer biologically active molecules, including lipids, nucleic acids, and proteins, between cells, which influence pathological and physiological processes (1–3). They are naturally created as intraluminal vesicles within multivesicular bodies that are later released into the body fluids, including saliva, urine, and blood (4).

Since exosomes naturally originate from the cells of the human body, they exhibit high biocompatibility, which makes them very applicable in therapeutic applications (5, 6). Their therapeutic applications include them being used as drug delivery vehicles due to their ability to carry and deliver therapeutic molecules to certain targeted cells, which is crucial for treating different diseases such as cardiovascular diseases and neurodegenerative disorders (7). Also, exosomes can carry disease-specific biomarkers, making them beneficial in non-invasive diagnostic applications that can be used to monitor and detect diseases such as cancer (8).

When integrated into hydrogels, the exosomes' stability is improved, and their biological activity is well maintained. Additionally, this allows the release of exosomes into targeted regions in a sustained manner (9, 10). Also, exosome-embedded hydrogels can be used in bone regeneration, as exosomes enhance the hydrogels' regenerative capabilities by regulating inflammatory pathways and promoting osteogenic differentiation (11). Moreover, exosome-loaded hydrogels can be used in improving wound healing as the hydrogels can be used noninvasively on the wounds, providing a conducive region for cell regeneration, which will accelerate the healing rate (12). Also, nanoshells (similar nanostructures like exosomes), such as hyaluronic acid nanoshells, can also be used for drug delivery, where they have been studied in delivering antineoplastic drugs to gliomas and enhancing the performance of contrast agents in nuclear medicine and neuroradiology (13, 14).

In this paper, we analyze the growth of the usage of exosomes in hydrogels by examining the statistics of publications across different fields and countries, providing an overview of the expansion of such research areas worldwide. The statistics discussed in the paper are fully extracted from the Web of Science (WOS) and Scopus databases.

This bibliometric analysis paper examined the WOS and Scopus databases in the literature on utilizing exosomes in hydrogels. Both databases allow the advanced search of topics, where a query can be used to target papers of relevance and interest specifically. To maintain consistency between the searches of both databases, the advanced search consisted of identifying the words “exosomes” and “hydrogels” in the titles, abstracts, or keywords of the publications. Where keywords include indexed keywords, keywords plus, and author keywords. To increase the search accuracy, the query was adjusted to detect the aforementioned words in different forms, such as their singulars, plurals, and combinations, including “exosomes in hydrogels”. To ensure that both words are included together in the publications, the “AND” command was used inside the search criteria of abstracts, titles, or keywords without any “OR” command to avoid papers discussing exosomes or hydrogels separately. Both databases enable the extraction of the publication-related information, such as publication dates, authors, and number of citations, which can be used in the analysis. The extracted data was plotted using the Origin software. It is important to point out that the data presented in this review are approximations of very high accuracy. However, complete certainty is not achievable due to the continued increase in publication numbers, citations, and indexing in 2025. Additionally, the counts and proportions for WOS and Scopus were reported separately to avoid overlap, as some publications are indexed in both databases. The VOSviewer software was used to analyse the co-occurrence of keywords extracted from publications in both databases.

The data from the databases of Scopus and WOS indicated different numbers of publications, with Scopus giving a higher number of publications. That could be due to the fact that the database of Scopus includes more journals than that of WOS. To minimize the differences as much as possible, an advanced search was used in both databases that searched for the keywords of “exosomes” and “hydrogels” in their various forms in the titles, abstracts, and keywords of the publications. Several publications were thoroughly investigated to ensure that the search resulted in relevant publications, and some were excluded due to irrelevance.

As shown in Figure 1, the analysis performed in this study includes publications of the selected types from 2015 to May 9–11, 2025. It is important to point out that initial publications in this field (2–3 publications) in 2013 and 2014 were ignored to maintain consistency between the two databases. In WOS, the highest number of publications recorded was in 2024, with a total of 163 publications accounting for 28.10% of the total selected types publications. Similarly, in Scopus, the highest number of publications recorded was also in 2024, with a total of 361 publications accounting for 27.66% of the total publications. Both databases exhibit a clear, significant increasing trend in publications in recent years, which indicates the increased interest in the subject field.

Various types of publications are included in the databases of WOS and Scopus, as shown in Figure 2. This review only includes the publications categorized as articles, reviews, editorials, book chapters, conference papers, letters, conference reviews, retractions, books, and correction, while pre-prints are not included. The types included from WOS and Scopus are only the exact matching terminologies and selected unique terms. A zero value may reflect differences in labeling rather than the absence of publications. The majority of the publications relevant to this field in both databases are scientific articles. The second highest type of publications in both databases are review documents. For instance, the record of articles in WOS is 442 publications, and 738 publications in the Scopus database, accounting for 76.21% and 56.55% of the total publications per database, respectively. Similarly, the record of review papers in the WOS database is 127 publications, and 502 publications in the Scopus database, accounting for 21.90% and 38.47% of the total publications per database, respectively. Hence, the Scopus database comprises of 56.55% research articles and 38.47% review papers. The WOS database comprises of 76.21% research articles and 21.90% review papers.

As seen in Figure 2, Scopus covers document types that are not covered in the WOS database such as conference papers and conference reviews. This could be another reason for the difference in the number of publications between the two databases.

Although publication trends have been showing a significant increase in numbers, the number of clinical trials and patents remains low. An online search outside Scopus and WOS, as they do not index such documents, revealed that very few clinical trials and patents relative to publications exist. Such gaps between research output and translational activity are common in biomedical and biological fields, as it has been reported in areas such as nanomedicine for neuro-oncology (15).

Research about exosomes and hydrogels was contributed by several countries (Figure 3), including but not limited to China, Saudi Arabia, the United States of America (USA), England, and Iran. According to both databases, China is the most significant contributor to the research in this field, with 442 publications recorded in WOS and 808 in Scopus, accounting for 76.21% and 61.92% of the total publications, respectively. Both databases rank the top 4 countries as follows: China, USA, Iran, and India. The lowest-ranked country in the top 10 list in the WOS database is Italy, with only 6 publications accounting for 1.03% of the total number of publications. On the other hand, Scopus ranks Australia the lowest of the top 10 countries, with a contribution of 24 publications accounting for 1.84% of the total number of publications.

According to the Scopus database, there are around 159 funding agencies recorded in this field. However, the database of WOS indicates a larger number of funding agencies. The top 10 funding agencies according to the WOS and Scopus databases are listed in Tables 1, 2, respectively. It is important to point out that several agencies are commonly listed in the top 10 agencies recorded in both databases.

As indicated in Table 1, the funding agency recorded in the WOS database with the highest number of publications is the National Natural Science Foundation of China NSFC, with a total of 290 publications. The highest-ranked agencies from the USA were the National Institutes of Health NIH USA and the United States Department of Health and Human Services. These were ranked at 5th and 6th positions with 26 publications each. The lowest-ranked Chinese agency was the Beijing Natural Science Foundation, with a total of 13 publications. From Table 1, it is clear that the Chinese agencies are the top contributors to research in this field, which reflects their advancement and high interest in the area.

As listed in Table 2, the funding agency recorded in the Scopus database with the highest number of publications is the National Natural Science Foundation of China, with a total of 529 publications. The highest-ranked agencies from the USA were ranked at 4th and 5th positions, with a total number of publications of 97 and 78, respectively. The lowest-ranked Chinese agency is the Fundamental Research Funds for the Central Universities, with a total of 46 publications. Unlike the records from the WOS database, the Scopus database indicates that the European Commission Agency ranked at 10th position in the top 10 agencies, with a total of 41 publications. b.

Paper Publication

The databases of WOS and Scopus have various categories, with the categories of WOS being more specific while the categories of Scopus are broader (Figures 4a,b). According to the Scopus database, the top three ranked areas are Biochemistry, Genetics and Molecular Biology, Engineering, and Materials Science with 635, 506, and 463 publications, respectively. The lowest-ranked area according to the Scopus database is the Earth and Planetary Sciences field, with only 1 publication.

According to the WOS database, the top three ranked areas are Materials Science, Science Technology Other Topics, and Engineering with 235, 168, and 146 publications, respectively. The lowest-ranked area according to the WOS database was Sport Sciences, with only 1 publication along with several other areas such as Optics, Nursing, Metallurgy, and Pathology.

Figure 5 shows the top 10 affiliated organizations in terms of the number of publications according to both WOS and Scopus databases (Figures 5a,b). All the top-ranked organizations are Chinese according to both databases. The top three ranked organizations according to WOS are the Ministry of Education China, Shanghai Jiao Tong University, and Zhejiang University, with a list percentage contributions of 17.2%, 14.5%, and 12.1%, respectively. The Scopus database ranks the same 1st and 2nd organizations, but ranks the Southern Medical University as third with a contribution of 10.7% to the list. Most of the organizations are common in both databases, with changes in the order of ranking. c.

Preferred Publications

The WOS and Scopas databases share seven out of the ten most cited publications on the topic of utilizing exosomes in hydrogels. It is important to point out that one publication was omitted from the list of Scopus due to its irrelevance. The omitted paper discusses tumor-associated macrophages immunotherapy, but was included in the search due to the words “exosome” and “hydrogel” being in the indexed keywords. The top-ranked publications presented in Table 4 consist of research articles and review papers, with the majority originating from China, while 1 publication originates from each of the USA, USA/France collaboration, and USA/UK collaboration. The publication with the highest citation count is titled “Engineering Bioactive Self-Healing Antibacterial Exosomes Hydrogel for Promoting Chronic Diabetic Wound Healing and Complete Skin Regeneration” by Wang et al., published in the Theranostics Journal in 2019. This publication has a citation record of 651 in the WOS database and 692 in the Scopus database. The most recent publication in the list is titled “Extracellular vesicle-loaded hydrogels for tissue repair and regeneration” by Yikun Ju et al., published in the Journal of Materials Bio Today in 2023. This publication has a citation record of 244 in the WOS database. The highest cited publication recognized only in the WOS database is titled “Exosomes derived from miR-375-overexpressing human adipose mesenchymal stem cells promote bone regeneration” by Si Chen et al., published in the CELL PROLIFERATION in 2019. This publication has a citation record of 257 in the WOS database. The highest cited publication recognized only in the Scopus database is titled “Genesis and growth of extracellular-vesicle-derived microcalcification in atherosclerotic plaques” by Joshua D. Hutcheson et al., published in the Journal of Nature Materials in 2016. This publication has a citation record of 307 in the Scopus database.

The top cited publications per database (Table 4) can be categorized using their intended application. Cardiovascular and vascular pathology/repair, as well as skin and soft tissue wound healing categories, contribute the most to the list with a contribution of around 30.8% and 23.1%, respectively. While the musculoskeletal regeneration (bone and cartilage), spinal cord injury treatment, and tissue regeneration/reviews categories contribute equally to the list, with a percentage of 15.4% each.

The top 10 most recent publications in both databases are listed in Table 5. All the publications listed were published in 2025. Notably, around 30% of the publications in the list are published in the Journal of Nanobiotechnology. Also, the Chinese Journal of Tissue Engineering Research and the Bioactive Materials journal each have publications accounting for 10% of the listed publications. The publications from both databases include articles and review papers that investigate different applications, including cardiac repair, burned skin repair, diabetic wound treatment, bone repair, and the treatment of infectious tissue injuries. The top 10 most recent publications per database (Table 5) can be categorized using their intended application. Musculoskeletal regeneration (bone, cartilage, and tendon) as well as the reviews categories, contribute the most to the list with a contribution of around 21.1% and 15.8%, respectively. The spinal cord injury treatment category has a contribution of 10.5%. While the cardiovascular repair and organ repair (kidney) categories contribute equally to the list, with a percentage of 5.3% each. As seen in Table 5, several publications include the utilization of EVs instead of exosomes; this is mainly due to their inclusion of terms such as exosomes and hydrogels in their keywords.

Figures 6a,b present the top 10 authors with respect to the record of the number of publications. According to the WOS database, Liu Y is the author with the highest contribution in this field, with a contribution accounting for 16.8% of the top 10-authors list. However, according to the Scopus database, Zhao Y. is the author with the highest record of publications, with a contribution of 13.3% to the list in the field of interest.

Although there are differences between the list exported from the WOS database and the Scopus database, it is important to point out that several authors are common between the two databases at higher rankings due to the difference in the number of publications recorded in each database. d.

Analysis of Keywords

This study analysed the global research trends of the utilization of exosomes in hydrogels for various applications from 2015 to 9th–11th of May 2025 using data exported from the databases of WOS and Scopus. The data obtained reveal that a significant increasing trend exists in both the number of publications and citations in the field over the past decade, indicating a growth in the interest of this field in academic and clinical research. China has been the most dominant contributor to this field in terms of the number of publications, with several Chinese institutions affiliated with the most effective publications in the field. The publication with the highest citation count received 651 and 692 citations based on the WOS and Scopus databases. This record of citation is relatively average compared to other fields but notably high for this relatively new field of study. The main research areas that contribute to this field include material science, engineering, science and technology, and chemistry, which reflects the multidisciplinary nature of the exosome-hydrogel research field. This study provides an overview of the current evolution of research in exosome-hydrogel applications over the past decade and provides convenient insights for further development in this field in the future. Future work could expand the search to include additional types of EVs, such as macrovesicles and apoptotic bodies, and analyze them separately. Furthermore, carrier systems apart from hydrogels, such as nanoshells, can be explored.