Laponite-reinforced marine bioinspired injectable self-healing adhesive chitosan-based hydrogel for infected wounds

Standard dressings struggle to conform to irregular wounds, which can easily lead to bacterial infection and impair the healing process. In this study, an injectable, self-healing hydrogel inspired by mussel and oyster adhesion was developed from dihydrocaffeic acid-modified chitosan, oxidized sodium alginate, and Laponite nanosheets. Benefiting from the synergistic reinforcement of dynamic imine bonds and the physical filling of the nanosheets, along with other physical interactions, the hydrogel can be extruded through a syringe and form filaments approximately 0.5 mm in diameter. By enabling slow catechol oxidation while limiting oxygen diffusion in the confined nanospace, Laponite nanoplatelets conferred the hydrogel a wet adhesion strength of 520.2 kPa on porcine skin at 24 h. The hydrogel with Laponite is shown to reduce the survival rates of S. aureus to below 0.98% indicating effective bactericidal efficacy. In vitro experiments demonstrated that the hydrogel significantly promotes the proliferation, migration, and angiogenesis of HUVECs. Animal experiments confirmed that the hydrogel accelerates epidermal regeneration and collagen deposition, reduces the inflammatory factor TNF-α, and upregulates the expression of angiogenesis-related genes. More importantly, the hydrogel achieved a 96.7% closure rate for S. aureus-infected wounds by day 13.