Chitosan-Based Thermal-Coagulation Hydrogel System Driven by Multiple Interactions: Oxidation-Induced Fast Gelation and Enhanced Performance

The application of the chitosan/β-glycerophosphate (CS/β-GP) system is limited due to its weak mechanical performance, high concentration of β-GP, and slow gelation. To revitalize this thermal-coagulation system, we used catechol-chitosan (CS-C) and systematically investigated the influence of modification. By controlling the grafting rate, it was found that the solution pH and p<i>K</i>_a of CS-C were both affected by the decrease of the amino groups, whereas the gelation time and the required β-GP content for gelling significantly decreased. Using the oxidative properties of the catechol groups, the CS-C/β-GP hydrogel showed a 10-fold increment in stiffness, rapid gelation (1-2 min), and a much lower β-GP content (2-6 wt %). In addition, the hydrogel performed well in antimicrobial and biocompatibility tests. This is the first work to elucidate the thermal-coagulation mechanism of modified chitosan systems, making the application of chitosan-based thermal-coagulation systems in the field of biomedicine and tissue repair possible.