Incorporation of g-C3N4 photocatalyst into carboxymethyl chitosan/polyvinyl alcohol hydrogel to synergistically enhance antibacterial activity and wound healing

Bacterial wound infections pose an escalating threat to global public health. Herein, we developed a visible-light-responsive antibacterial hydrogel dressing by incorporating graphitic carbon nitride (g-C 3 N 4 ), carboxymethyl chitosan (CMCS), and polyvinyl alcohol (PVA) (termed as g-C 3 N 4 @CP) crosslinked through borate ester bonds and hydrogen bonds using boric acid. Through systematic optimization, the hydrogel loaded with 0.7 g/L g-C 3 N 4 exhibited excellent swelling capacity, mechanical robustness (rupture elongation, 2471.85%; compressive strength, 1008 kPa), and intrinsic self-healing ability. Macroscopic healing occurred within 30 minutes through interfacial contact, with healed samples retaining structural integrity under severe deformation (bending, knotting). Leveraging the synergistic antibacterial effect of g-C 3 N 4 nanosheets and CMCS chains, the hydrogel achieved exceptional photocatalytic antibacterial activity, eliminating 86.81 ± 0.58% of Escherichia coli and 94.31 ± 0.94% of Staphylococcus aureus under visible-light irradiation. Remarkably, bacterial membrane disruption was confirmed through substantial cytoplasmic protein leakage from S. aureus after treatment. In vivo experiments further validated the dual functionality of the hydrogel: potent suppression of bacterial proliferation in infected wounds and significant acceleration of tissue regeneration after visible-light irradiation while exhibiting excellent biocompatibility. It is expected to be applied to wound dressing in the future.