Catechol-grafted chitosan-based antioxidant hydrogel with rapid self-healing property for wound healing

Chronic wounds, particularly those with non-healing ulcers, show high levels of oxidant stress, such as excessive reactive oxygen species (ROS), which delays the healing process. Bacterial infections in wounds increase the need for antibiotics, which brings up serious concerns regarding antibiotic resistance. The innovative antibiotic-free strategies to endow the hydrogels with antibacterial and antioxidant features including the grafting of ROSscavenging moieties onto the hydrogel structure are in high demand for wound management. Herein, an antibacterial and antioxidant hydrogel with rapid self-healing performance was fabricated via the dynamic borate ester cross-linkages between catechol-grafted chitosan (CS-CA) and polyvinyl alcohol in the presence of borax with the incorporation of ellagic acid (EA). Benefiting from the catechol groups from EA and CS-CA, the resulting hydrogel exhibited desirable adhesive property, excellent antioxidant and intensified antibacterial dual functions. Furthermore, the hydrogel demonstrated remarkable biocompatibility and pH-responsive behavior for the controlled release of EA, attributed to the reversible characteristics of borate ester linkages. Notably, these multifunctional hydrogels exhibited substantial regenerative capabilities in wound healing, as evidenced by in vivo assessments conducted on a full-thickness skin defect model, highlighting their considerable potential as wound dressings for effective wound management.