pH-responsive magnolol nanocapsule-embedded magnolol-grafted-chitosan hydrochloride hydrogels for promoting wound healing

Bacterial infection and oxidative stress seriously delay wound healing. Here, magnolol-grafted-chitosan hydrochloride (CSCl-MAG) was synthesized and crosslinked with genipin to form hydrogel (CSMH). By embedding magnolol-loaded chitosan nanocapsules (MCNGs) into CSMH, we designed a novel nanocapsule- embedded hydrogel dressing (MCNG-H) with sustained antibacterial and antioxidant properties. The swelling, rheology, cytotoxicity, antibacterial and antioxidant properties of MCNG-H were studied. MCNG-H exhibited good swelling properties and biocompatibility. The antibacterial and antioxidant assays in vitro demonstrated the corporative effect of CSM-H and MCNGs in inhibiting bacteria and eliminating reactive oxygen species (ROS). Moreover, MCNG-H revealed the pH-responsive release profiles of loaded MAG, and ensured sustained release of MAG with the dual protective effects of MCNG and CSMH, which helped to maintain long-term antibacterial and antioxidant activities. Finally, MCNG-H significantly accelerated wound healing in a splinted excisional dermal wound model, promising a competitive dressing for the treatment of infected wounds.