Exploring Swelling Behaviour of Chitosan-Based Hydrogels in Diverse Environmental Conditions

Abstract

Hydrogels, versatile materials with diverse applications in biomedicine and beyond, have garnered significant attention due to their unique properties. Among these, chitosan-based hydrogels have emerged as promising candidates owing to their biocompatibility, biodegradability, and antimicrobial properties. The hydrogels were synthesized through cross-linking of chitosan graft copolymers with N-vinylpyrrolidone and other vinyl monomers, as well as through thermal methods in situ. The impact of cross-linking agent concentration on gel fraction yield and cross-linking efficiency was examined. The results indicate that higher cross-linking densities lead to reduced swelling capacity as a result of a denser network structure. The swelling behaviour of chitosan-based hydrogels under various environmental conditions, including pH, temperature and ionic strength were also investigated. It is found that swelling behaviour varied among different hydrogel formulations, with natural and vinyl graft copolymers exhibiting increased swelling in acidic environments. Semi-synthetic copolymers containing hydrophobic groups showed relatively lower swelling across pH ranges. Additionally, swelling kinetics were studied, revealing equilibrium reached at different time intervals depending on temperature and hydrogel composition. Furthermore, the effect of glucose concentration on swelling behaviour was explored, demonstrating decreased swelling with increasing glucose concentration. Overall, this comprehensive investigation provides valuable insights into the swelling behaviour of chitosan-based hydrogels, essential for optimizing their performance in biomedical applications.