An injectable in situ-forming hydrogel with self-activating genipin-chitosan (GpCS) cross-linking and an O/Ca self-supplying capability for wound healing and rapid hemostasis.

Severe traumatic bleeding and chronic diabetic wounds require rapid hemostasis and multifunctional dressings, which remain particularly challenging, especially for non-compressible trauma and irregular wounds with dysregulated microenvironments. Chitosan (CS) can be easily cross-linked with genipin to form GpCS hydrogels. However, developing injectable GpCS hydrogels for biomedical applications faces challenges, particularly in enhancing rapid gel formation and optimizing physical properties. In this study, we present an innovative approach to improve these aspects by designing a novel injectable GpCS hydrogel, strategically enhanced through a calcium peroxide (CaO)-activated cross-linking reaction. CaO played a pivotal role in promoting in situ cross-linking of the GpCS hydrogel, leading to significant improvements in its injectable in situ gel-forming ability, mechanical strength, and self-healing and bioadhesive properties. CaO incorporated in the hydrogels rapidly converted to oxygen when combined with catalase (CAT), thereby establishing a self-sustaining oxygen/calcium release system. This system not only promoted hyperoxia and activated the coagulation cascade, facilitating rapid blood clotting, but also significantly accelerated wound healing through enhanced angiogenesis, collagen deposition, and M2 macrophage polarization. These attributes significantly enhanced the capacity of the hydrogel to facilitate wound closure and hemostasis, highlighting its therapeutic value in accelerating recovery and improving healing outcomes in clinical wound care.