Light-switchable delivery of pterostilbene from polysaccharide hydrogel for promoting cutaneous wound healing

Antioxidant and antibacterial hydrogel dressings with excellent biocompatible properties have attracted attention in wound repair due to severe wound infection and excessive reactive oxygen species, which delay wound healing and threaten human health. This work employed a light-switchable hydrogel that responsive to ultraviolet in order to suppress excessive reactive oxygen species and accelerate cutaneous wound healing. The hydrogel was formed by dynamic imine bonds between carboxymethyl chitosan and oxidized hyaluronic acid, which loaded with pterostilbene/azobenzene-grafted mesoporous silica (MPte) nanoparticles. By incorporating MPte nanoparticles, the hydrogel system exhibited robust self-healing and enhanced mechanical strength (ca. 494.7 kPa). Besides, the incorporation of MPte nanoparticles significantly improved the release of pterostilbene from both the MPte nanoparticles and the hydrogel systems under ultraviolet irradiation. The incorporation of pterostilbene provided the hydrogel system with excellent cytocompatibility in vitro, along with great antibacterial efficiency against S. aureus (ca. 87.2%) and enhanced DPPH radical scavenging rate almost 2 times that of the pure polysaccharide hydrogel. Based on the light-switchable nanoparticles and the bioactive polysaccharide matrix, the hydrogel system exhibited excellent wound healing performance in a mouse full-thickness skin wound model. Taken together, the functionalized hydrogel system exhibits great biocompatibility enable the development of smart hydrogel dressings capable of promoting wound repair and providing therapeutic benefits.