Superabsorbent Chitosan-Based Nanocomposite Antibacterial Hydrogel for Biofilm Disruption and Accelerated Healing of Infected Wounds

Chitosan-based hydrogels, owing to their unique barrier protection properties, have garnered significant attention as wound dressings. Improving the liquid-absorption and antimicrobial capabilities of chitosan hydrogels will further broaden their applications in this field. In this study, chitosan was modified with quaternary ammonium salt and glycidyl methacrylate and then combined with negatively charged gold–platinum nanodots (AuPt NDs) to construct a type of nanocomposite antibacterial hydrogel. Structurally, the hydrogel possesses a loose and porous structure. It can absorb about 800% of its own mass in pure water and has excellent pro-coagulant activity. These properties are beneficial for wound healing. Mechanistically, the positively charged hydrogel is capable of adsorbing negatively charged bacteria, disturbing the potential balance of the bacterial cell membranes, which can reduce the activity of the bacteria and lead to dissipation of the bacterial biofilm. Furthermore, the hydrogel antimicrobial effect can be greatly enhanced by the incorporation of AuPt NDs, enabling it to catalyze the production of ·OH from a low concentration of H2O2 and generate heat under 808 nm laser irradiation, thereby further killing the bacteria and promoting the dissipation of the biofilm effectively and rapidly. More importantly, the hydrogel has excellent biocompatibility and facilitates the healing of wounds infected with bacterial biofilms, holding great potential for application as a medical wound dressing.