Based on the Web of Science search, 959 documents were considered suitable for scientometric analysis, and the following results were obtained: language, publication and citation history, types of documents, thematic areas published, most cited works, publishers that publish the most and the most cited journals, countries, institutions and authors that publish the most in the area of bacterial nanocellulose.
3.1 Language
Of the 959 documents analyzed, there was a solid majority in English, in 941 of them, for a total of 99.053%. The remaining languages were Russian, Chinese, German, Portuguese and Spanish. This absolute proportion of English is explained by it being the universal scientific language adopted, as it has a wider reach (Cruz; Andrade; 2021).
3.2 Type of document
The documents found on bacterial nanocellulose come in a variety of formats, as can be seen in Table 1.
Table 1
Types of documents documents found and their respective quantifications
Type of document | Quantity |
Article | 756 |
Review Article | 125 |
Abstract | 44 |
Article of Conference | 25 |
Early Acess | 11 |
Editorial Material | 5 |
Letter Book Chapter | 2 1 |
The result of the types of documents found showed that about 79% are articles, followed by 13% of review articles, 8% of abstracts and other writing methodologies are a minority. This choice is made according to the objective of scientific work, which is to publish knowledge in such a way that it can be understood without difficulty (Rabelo, 2018).
3.3 History of publications and citations
The history of publications and citations obtained in graph form can be seen in Fig. 2.
Based on the results of the history of publications and citations, it can be determined that the topic of bacterial nanocellulose has been constantly growing since 2013, when publications totaled 26 per year and continued to increase until they reached 147 publications in 2023. This increase can be justified by the advances in discoveries of its functionalization and biomedical applications that preceded the period (Klemm et al., 2021). Following this same line of evolution are the citations, which grow more sharply from 2013, with 150 citations, to 2023 with 6516 citations.
Therefore, by analyzing the history of citations and publications, it is possible to see that there is a growing advance in research on the subject during the period from 2006 to 2023. Furthermore, through the equation generated by the graph equal to:
It is possible to predict a number of publications equal to 175 documents for the year 2030, and this data and the growing number of citations indicate that studies into bacterial nanocellulose will continue to grow over the coming decades.
3.4 Keywords
The main keywords used by the articles analyzed can be seen in Fig. 3. The most frequent keyword was nanocellulose, co-occurring in 172 articles, followed by the words cellulose (101), composite (77), mechanical properties (77), and nanocomposite (65). The high occurrence of the terms nanocellulose and cellulose was expected, given that they are the main focus of the research, while the other words can be justified by the biomaterial's applications. Bacterial nanocellulose has structural characteristics such as high porosity and micro-scale pores that allow it to be incorporated into other materials, making it possible to manufacture composites or nanocomposites with varied functional properties and applications (Takama et al., 2021; Meek; Dunnen, 2009).
In addition, it is possible to observe a strong link between the words bacterial cellulose and biocompatibility, indicating that many of the articles that talk about bacterial cellulose also discuss the biocompatibility of this material. The biocompatibility of BNC is one of its main characteristics, and allows it to be applied in the biomedical field as biocuratives and scaffolding for tissues, and also in the cosmetics field in creams and facial masks (Borba et al., 2022; Wu et al., 2021). However, through the color of the link that connects one word to another, it is possible to see that this co-occurrence is old. Since biocompatibility is a property that has already been well described, the most recent articles do not focus so much on this issue, but instead seek to explore the materials that can be incorporated and the possible applications.
Another interesting point to note is the fact that the expression "in vitro" appears in the image 28 times. This is an indication that research into bacterial nanocellulose is recent and mostly at the laboratory testing stage. Only 5 articles use the term "in vivo" and 4 use "in situ". These results indicate that in the coming years the number of publications focused on in vivo tests will increase.
3.5 Keyword clusters
Figure 4a shows the grouping (clusters) of the co-mentioned keywords. The grouping is done according to the similarity of the keywords analyzed, with each group being numbered and named in descending order according to its size. The first cluster (#0 komagataeibacter xylinus) is made up of 60 keywords, and refers to one of the main species responsible for producing bacterial nanocellulose (Shingania et al., 2022). The second group was named #1 nanotechnology. Nanotechnology studies matter on an atomic and molecular scale, and is the science responsible for understanding the structure, functioning and application of nanoparticles such as bacterial nanocellulose.
Clusters #3 (adsorption), #6 (transparency) and #9 (aligned nanocellulose) refer to the physicochemical properties of BNC. Due to its high porosity, BNC has the ability to adsorb various materials, which can be inserted into the culture medium or by an immersion process, in order to confer new physicochemical properties to the material, such as the addition of antimicrobial agents (#7 antimicrobial activity) and the incorporation and delivery of drugs (#2 protein delivery).
Transparency is a physical characteristic that attracts great interest, since a transparent biofilm has optical characteristics that make its use more attractive (Souza et al., 2019). Cluster #9 is related to the molecular organization of the nanocellulose in an aligned manner, since the alignment of the nanofibres makes it possible to obtain better mechanical properties, giving the material greater strength (WU et al., 2020). Cluster #5 (bovine cartilage punch model) is related to a more specific application. Several researchers have studied the use of BNC to help regenerate bovine cartilage, with the aim of replacing the methods that are traditionally used with a more effective model. Authors such as Pretzel et al. (2013) and Hobert et al. (2019) carried out in vitro tests and obtained good results.
Figure 4b shows the size of each cluster, how many keywords each group has, and also the silhouette of each cluster. The silhouette refers to the homogeneity of the cluster; the closer the silhouette is to 1.0, the greater the similarity between the keywords (Wang et al., 2019). However, it is important to consider the size of the group when assessing homogeneity, as in small groups such as #9 the high silhouette value may not be very significant.
3.6 Citation analysis
From the citation analysis carried out, it can be seen that among the 942 research documents there were 16747 citations by other articles, of which 16006 articles were not self-cited. In addition, the analysis of citations made found a number of 28654, of which 24504 were not self-citations. Based on the citations made, an average value of 30.42 citations per document and an H-index of 79 were obtained. The H-index value is used as a parameter to measure the quality of a researcher's work, how relevant the published document is in the field (Thomaz et al., 2011).
3.7 Most cited papers
The most cited papers are determined to be the most influential in the research area. Regarding bacterial nanocellulose, these documents can be identified in Table 2.
Table 2
List of the most cited papers with their authors and metrics
Title | Total citations | Average per year | Author/Year |
Key advances in the chemical modification of nanocelluloses | 1092 | 99.27 | Habibi, 2014 |
Comparison of the properties of cellulose nanocrystals and cellulose nanofibrils isolated from bacteria, tunicate, and wood processed using acid, enzymatic, mechanical, and oxidative methods | 451 | 41 | Sacui; Nieuwendaal; Gilman et al., 2014 |
Bilayered biofoam for highly efficiente solar steam generation | 44 | 49.33 | Jiang; Tian; Singamaneni et al., 2016 |
Nanocelluloses as innovative polymers in research and application | 393 | 20.68 | Klemm; Schumann; Marchch et al., 2006 |
Bacterial cellulose-based material and medical devices: current state and perspectives | 377 | 26.93 | Petersen; Gatenholm 2011 |
Muscle-Inspired Highly Anisotropic, Strong, Ion-Conductive Hydrogels | 375 | 53.57 | Kong; Wang; Hu et al., 2018 |
Bacterial cellulose biosynthesis: diversity of operons, subunits, products, and functions | 337 | 33.7 | Römling; Galperin, 2015 |
Surface Modification of Bacterial Cellulose Aerogels’ Web-like Skeleton for Oil/Water Separation | 318 | 31.8 | Sai; Fu; Zhang et al., 2015 |
Bacterial cellulose as a material for wound treatment: properties and modifications. A review | 283 | 28.3 | Sulaeva; Henniges; Potthast et al., 2015 |
More Than Meets the Eye in Bacterial Cellulose: Biosynthesis, Bioprocessing, and Applications in Advanced Fiber Composites | 278 | 25.27 | Lee; Buldum; Bismarck et al., 2014 |
There are several factors that make an article have a large number of citations, including the structure of the titles. Titles that suggest the result of the research and contain keywords make it easier for search engines to find the article (Mendes da Silva, 2020). This characteristic can be seen in most of the most cited articles, with the terms "nanocellulose", "bacterial cellulose" and "cellulose" being frequent.
In addition, another important aspect is the author's productivity, so a positive relationship can be analyzed between the most cited papers and the most cited authors, where Habibi, Sacui, Jiang, Klemm and Petersen are included in both analyses (Mendes da Silva, 2020).
3.8 Most cited journals
Through the most cited journals, it is possible to predict which journals are the most relevant to the topic in question. Figure 5 shows the connection network of the most cited journals, with Carbohydrate Polymers having the highest number of citations (459). This journal is published by Elsevier and is one of the leading journals when it comes to glycoscience, the science that studies the synthesis and application of molecules containing carbohydrates. It has an impact factor (JCR) of 11.2, with an H index of 251, which ranks it 3rd out of 88 in Polymer Science.
By looking at the most cited journals, it is possible to assess their degree of importance in the scientific sphere using the impact factor and H-index metrics. These parameters can be seen in Fig. 6 on the journals in evidence in the field of bacterial nanocellulose.
3.10 Countries with the most publications
In general, the countries with the highest number of publications are those with the greatest investment in education, science and technology. In this sense, Fig. 7 shows that the countries that have published the most in relation to BNC are China (189) and the United States (91), both developed countries with high funding for nanotechnology research. According to the report Nanotechnology: A Policy Primer (2016) published by the US Congressional Research Service, although the United States is responsible for around a third of research and development funding in nanotechnology, China and some European Union countries have stood out in terms of the number of publications in the area.
Brazil is in fourth place as the country that publishes the most. This is a reflection of the Brazilian groups that study nanocellulose and enable this significant advance in the field.
3.11 Most cited authors x authors with the most publications
Figure 8 shows the relationship between the most cited authors (a) and the 10 authors with the most publications on the subject (b). The influence of authors can be seen in the citations, which indicate that the work published by certain authors is accessed and serves as a reference for the development of new research. It is therefore possible to see that there is not necessarily a direct link between the authors who publish the most and the most cited. The most cited author (Habibi), with 1,094 citations, is not the author with the most publications out of the 959 documents analyzed.