Speaker
Description
Chitosan is a well-known polymer widely used in tissue engineering and regenerative medicine. It is biocompatible, biodegradable, non-toxic, has antibacterial and osteoconductive properties. It is perfect for the production of implantable materials, including porous scaffolds. Unfortunately, as with most natural polymers, chitosan structures exhibit poor mechanical properties, low durability, and rapid degradation. To counteract these problems, chitosan is sometimes combined with fillers, e.g. bioglass particles, to form more durable composites. However, the best method of obtaining stable chitosan structures is to carry out cross-linking processes. Methods of cross-linking chitosan, for example by creating chemical bonds or physical cross-linking, directly between the polymer chains or between the polymer chains and molecules of multifunctional cross-linkers, are known [1]. There are also methods of stabilizing ready-made chitosan scaffolds. The cross-linking density and the properties of the obtained structures depend on the cross-linking method, the type and amount of the cross-linking agent used, as well as the process conditions. The absence of a cytotoxic effect is also an important aspect in the selection of a cross-linking agent for biomaterials.
The natural crosslinking agent for chitosan can be 4-hydroxy-3-methoxybenzaldehyde known as vanillin (VAN). The chemical cross-linking reaction of chitosan with vanillin is based on a reaction involving the amine groups of chitosan and the aldehyde group of vanillin, resulting in the formation of a Schiff's base and a color change from light yellow to strong yellow. Besides, the vanillin hydroxyl group can also form a hydrogen bond with the hydroxyl or amino group of chitosan [2]. As a result of these reactions, a dense three-dimensional polymer network is formed, which stabilizes the chitosan structures.
The aim of the study was to determine the optimal conditions for stabilization/cross-linking of chitosan/bioglass composites with the use of a natural cross-linking agent - vanillin, in terms of obtaining mechanically stable three-dimensional porous scaffolds with porosity suitable for the colonization and proliferation of cells and showing no cytotoxic effect.
As part of the work, cross-linking of chitosan with the use of vanillin as a component of composite masses as well as the stabilization of porous chitosan structures with the use of vanillin solutions was carried out. Cross-linked and/or vanillin-stabilized composites were tested for microstructure (SEM imaging and mean pore size determination), water absorption and solubility tests, mechanical compressive strength tests, and cytotoxicity and proliferation tests. It has been shown that properly selected conditions of the cross-linking and/or stabilization process with the participation of vanillin allow to obtain durable and mechanically resistant chitosan scaffolds with an appropriate microstructure and desired biological properties.
[1] Anna Woźniak, Monika Biernat “Methods for crosslinking and stabilization of chitosan structures for potential medical applications”, Journal of Bioactive and Compatible Polymers, 37(3) (2022) 151-167 DOI: 10.1177/08839115221085738
[2] Chuanhui Xu, Wei Zhan, Xiuzhen Tang, Fang Mo, Lihua Fu, Baofeng Lin, “Self-healing chitosan/vanillin hydrogels based on Schiff-base bond/hydrogen bond hybrid linkages”, Polymer Testing, 66 (2018) 155-163 DOI: 10.1016/j.polymertesting.2018.01.016
This research was funded by The National Centre for Research and Development, Poland, grant No. TECHMATSTRATEG2/406384/7/NCBR/2019
41883659526
