Flexible and elastic chitosan-based hydrogel film dressings for second-degree partial-thickness burn wound healing

Chitosan (CS)-based hydrogel films have attracted intense and increasing interest for healing burn wounds owing to their strong biocompatibility and hemostatic potential. However, conventional CS hydrogels suffer from poor mechanical strength and structural instability under exudate exposure, limiting their clinical efficacy. Herein, a floccule self-deposition/redissolution strategy is implemented to develop a flexible and transparent CS-based hydrogel film with enhanced hemostasis and wound healing properties. Acetic acid is used to redissolve CS floccules, expanding intermolecular distances to reduce intramolecular hydrogen bonds and expose more bioactive amino groups. Glycerin is incorporated as a plasticizer to enhance the mechanical properties. The as-prepared CS-based hydrogel film exhibits higher mechanical flexibility (~72% elongation at break) in dry conditions and maintains its structural integrity for 24 h in wet environments. It also exhibits a higher hemostatic ability (~122 s) than a traditional unprocessed CS-based hydrogel film (~315 s). A second-degree partial thickness burn wound model confirms that the CS-based hydrogel film can significantly regulate the inflammatory response and accelerate the collagen deposition, thus promoting wound closure and healing. Overall, this study provides a facile approach to prepare CS-based hydrogel films with promising potential as dressings for burn wound healing.