Antibacterial conductive self-healable supramolecular hydrogel dressing for infected motional wound healing

Wounds on stretchable parts of the human body cause prolonged suffering and involve more severe healing processes than wounds on stationary parts. However, they have received insufficient attention compared with other types of chronic wounds. In this study, a novel supramolecular gelatin (GT) hydrogel composed of GT-graft-aniline tetramer and quaternized chitosan was presented. The hydrogel was crosslinked by monoaldehyde beta-cyclodextrin via host-guest interaction and dynamic Schiff base and was free from permanent covalent bonds, heavy metals, and oxidants. Given its dynamic feature, the hydrogel exhibited flexibility, self-healing, and tissue adhesiveness and well adapted to motion wounds. Moreover, the hydrogel was bioactive with conductivity, antioxidant property, hemostatic effect, antibacterial, and photothermal effect (the killing ratio for methicillin-resistant Staphylococcus aureus (MRSA) was higher than 99.8% after 5 min of near-infrared irradiation) and exhibited on-demand removability. In the full-thickness MRSA-infected motional wound healing experiment, this novel hydrogel exhibited a significantly enhanced wound healing efficacy with a fast wound closure ratio (about 99.0% for 14 days), mild inflammatory response, high level of collagen deposition, and enhanced re-epithelialization by downregulating interleukin-6 and CD68 and upregulating vascular endothelial growth factor. The results indicated that this hydrogel has great potential in wound healing and skin tissue engineering and serves as an inspiration for the design of supramolecular biomaterials.