Knowledge domain and hotspots analysis concerning applications of two-photon polymerization in biomedical field: A bibliometric and visualized study

Abstract

Objective: Two-photon polymerization (TPP) utilizes an optical nonlinear absorption process to initiate the polymerization of photopolymerizable materials. To date, it is the only technique capable of fabricating complex 3D microstructures with finely adjusted geometry on the cell and sub-cell scales. TPP shows a very promising potential in biomedical applications related to high-resolution features, including drug delivery, tissue engineering, microfluidic devices, and so forth. Therefore, it is of high significance to grasp the global scientific achievements in this field. An analysis of publications concerning the applications of TPP in the biomedical field was performed, and the knowledge domain, research hotspots, frontiers, and research directions in this topic were identified according to the research results.Methods: The publications concerning TPP applications in biomedical field were retrieved from WoSCC between 2003 and 2022, Bibliometrics and visual analysis employing CiteSpace software and R-language package Bibliometrix were performed in this study.Results: A total of 415 publications regarding the TPP applications in the biomedical field were retrieved from WoSCC, including 377 articles, and 38 review articles. The studies pertaining to the biomedical applications of TPP began back in 2003 and showed an upward trend constantly. Especially in the recent 5 years, studies of TPP in biomedical field have increased rapidly, with the number of publications from 2017 to 2021 accounting for 52.29% of the total. In terms of output, China was the leading country and Chinese Acad Sci, Tech Inst Phys and Chem was the leading institution. The United States showed the closest cooperation with other countries. ACS applied materials and interfaces was the most prolific journal (n = 13), followed by Biofabrication (n = 11) and Optics express (n = 10). The journals having the top cited papers were Biomaterials, Advanced materials, and Applied physic letters. The most productive author was Aleksandr Ovsianikov (27 articles). Meanwhile, researchers who had close cooperation with other researchers were also prolific authors. “cell behavior”, " (tissue engineering) scaffolds”, “biomaterials,” and “hydrogel” were the main co-occurrence keywords and “additional manufacturing”, “3D printing,” and “microstructures” were the recent burst keywords. The Keyword clusters, “stem cells,” and “mucosal delivery”, appeared recently. A paper reporting unprecedented high-resolution bull models fabricated by TPP was the most locally cited reference (cited 60 times). “Magnetic actuation” and “additive manufacturing” were recently co-cited reference clusters and an article concerning ultracompact compound lens systems manufactured by TPP was the latest burst reference.Conclusion: The applications of TPP in biomedical field is an interdisciplinary research topic and the development of this field requires the active collaboration of researchers and experts from all relevant disciplines. Bringing up a better utilization of TPP as an additive manufacturing technology to better serve the biomedical development has always been the research focus in this field. Research on stem cells behaviors and mucosal delivery based on microstructures fabricated using TPP were becoming new hotspots. And it can be predicted that using TPP as a sourcing technique to fabricate biomedical-related structures and devices is a new research direction. In addition, the research of functional polymers, such as magnetic-driven polymers, was the frontier topic of TPP biomedical applications.

Knowledge domain and hotspots concerning photosensitive hydrogels for tissue engineering applications: A bibliometric and visualized analysis (1996-2022)

“…The spatial resolution of the structures manufactured by TPP can reach below 100 nm. At present, it is the only technology capable of manufacturing complex 3D structures with precisely adjusted geometric shapes on a sub-cellular scale and is used to process engineering ECM ( Fu et al, 2022 ).…”

“…Hydrogels are three-dimensional (3D) natural or synthetic crosslinked networks composed of polymerization chains formed by hydrophilic monomers or macromers ( Qin et al, 2014 ; Gholamali and Yadollahi 2021 ). Due to the ability to simulate many properties of natural ECMs, hydrogels have been widely used in biomedical fields, such as drug delivery and tissue engineering ( Fu et al, 2022 ; Jing et al, 2022 ). Especially for TE, hydrogel scaffolds have captivated much attention because they provide cells with not only the mechanical supports but also the interconnected pores for permeating nutrients, oxygen and metabolite ( Qin et al, 2014 ).…”

“…As a statistical method combining quantitative and qualitative analysis, bibliometrics explores literature from multiple aspects, such as countries, institutions, journals, authors, keywords and cited literature, to identify the knowledge base, hotspots, frontiers, development trends of related research fields, and relationships between specific research areas. ( Chen 2004 ; Chen 2017 ; Zhang et al, 2021 ; Fu et al, 2022 ). With the continuous development of this discipline, bibliometrics has creatively visualized the information regarding the publications to form network maps, which assist researchers in intuitively grasping the important connotation and denotation implied in the literature ( Ellegaard and Wallin 2015 ; Gonzalez-Alcaide et al, 2017 ).…”

Development of biomedical hydrogels for rheumatoid arthritis treatment

“…Hydrogels have been continuously applied to fabricate lenses and drug delivery vehicles for medical purposes and tissue engineering [ 21 , 22 ]. Physically, hydrogels are soft, porous and elastic materials in which a polymer matrix encapsulates large amounts of water, drugs or other biological fluids without destroying the unique polymer matrix structure [ 23 , 24 ].…”

Biomedical engineering research in Chilean universities - A bibliometric analysis

“…It provides insight into the dynamics of scientific knowledge, trends, challenges, and research impact by identifying patterns and relationships between different features such as authors, publications, citations, and keywords [19]. Bibliometric analysis has contributed to several disciplines, such as business, electronics, energy, education, biology, and medicine, among others [18], [20], including BME [21]- [25].…”