A natural cordycepin/chitosan complex hydrogel with outstanding self-healable and wound healing properties.

The chitosan-based hydrogel dressings have been intensively engaged in wound healing. In respect to the relatively unsatisfied anti-bacterial performance of chitosan, we developed a self-healable cordycepin (abbreviated to CY)/chitosan (abbreviated to CS) hydrogel dressing cross linking by non-covalent bonds (hydrogen bond and electrostatic interaction) for wound healing through one-step 'freeze-thaw' method without adding any cross-linking agent. The as-prepared hybrid hydrogel exhibited excellent biocompatibility, suitable swelling ratio and desired mechanical strength, providing remarkable antimicrobial effect with no side effects in vitro. The self-healable property enables this hydrogel to adapt irregularly shaped wound defects without premolding. Moreover, our in vivo experiments confirmed that CY/CS hydrogel served as a quicker re-epithelization of skin wounds and an apparent increasing collagen deposition compared with chitosan hydrogels. Additionally, the CY/CS hydrogel significantly increased the expressions of epithelial regeneration markers including laminin and involucrin. The present study highlights a facile hydrogel strategy to balance and optimize the biocompatibility, swelling ratio and self-adapting ability for treating wound healing.