Speaker
Description
Introduction
The research concept is based on the [2+2] cycloaddition reaction of double bonds embedded in the modified polymer structure, enabling efficient and initiator-free hydrogel crosslinking upon light exposure. It is widely recognized that degradation by-products of photoinitiators exhibit cytotoxicity, which is a major limitation in the field of biomaterials engineering. To overcome this challenge, we initiated the development of materials capable of undergoing crosslinking independently of photoinitiators. The key strategy involved identifying compounds containing functional groups prone to UV-Vis light sensitization, incorporating them into polymer structures via coupling agents, and optimizing operational parameters for bioprinting applications. A library of hybrid materials was developed to enable the fabrication of highly biocompatible 3D scaffolds by tuning the combinations of different building blocks
Methods
To create a base of new materials, a series of optimization reactions were carried out to functionalize natural polymers. Biomaterials were obtained by functionalizing gelatin with acids such as coumarin-3-carboxylic acid, cinnamic acid or 4-vinylbenzoic acid using coupling reagents. In addition, a series of experiments were conducted to study the properties of the biomaterials. The functionality of the obtained biomaterials was demonstrated by determining the crosslinking profile of the materials, their rheological properties and printability. MTT tests were performed to determine the cytotoxicity profile of the materials, as well as comet assays to determine the level of cellular DNA damage in the obtained material compared to commercially available biomaterials. In addition, microscopic observations were performed and cell viability in the constructs was assessed using the FDA/Pi assay.
Results
As a result of conducted experiments, a class of biomaterials capable of crosslinking under UV-Vis light was created by taking advantage of their ability to perform cycloaddition reactions [2+2]. The materials showed excellent printability, as well as good biophysical properties, high biocompatibility, no cytotoxicity and low genotoxicity. In addition, the biomaterials exhibited photoprotective properties against cells inside the cross-linked structure. The concept used made it possible to eliminate the use of initiators in the crosslinking process.
Discussion
Focusing on the fundamental knowledge related to the application of cycloaddition reactions in material engineering, the research was mainly focused on crosslinking polymers by reacting identical groups with each other in a homodimerization reaction. The study was further extended to the cross-dimerization reaction of various derivatives. The selection of appropriate substituents introduced into the polymer structure makes it possible not only to eliminate the biohazardous photoinitiator, but also to modify the material's crosslinking parameters or its physicochemical, rheological, mechanical and biological properties for a specific application. As a result, the Clean-Cure product series was created, which has a wide potential in materials engineering and regenerative medicine applications.
References
[1] Nguyen AK, Goering PL, Reipa V, Narayan RJ. Toxicity and photosensitizing assessment of gelatin methacryloyl-based hydrogels photoinitiated with lithium phenyl-2,4,6-trimethylbenzoylphosphinate in human primary renal proximal tubule epithelial cells. Biointerphases 2019,14, 021007.
[2] Jiao, M., Han, D., Zhang, B., Chen, B., Ju, Y., A theoretical study on [2+2] cycloaddition reactions under visible light irradiation induced by energy transfer. Computational and Theoretical Chemistry 2017, 1117, 47-54.
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