Accelerating Interface NIR‐Induced Charge Transfer Through Cu and Black Phosphorus Modifying G‐C₃N₄ for Rapid Healing of <i>Staphylococcus aureus</i> Infected Diabetic Ulcer Wounds

Bacteria-infected diabetic wounds seriously threaten the lives of patients because diabetic ulcer tissues are quite difficult to repair while the bacteria infections deteriorate this course. Clinically used antibiotics cannot fulfil this mission but introduce the risk of bacterial resistance simultaneously. Herein, a near-infrared (NIR) light-responsive composite hydrogel is developed for rapid bacterial eradication and healing of Staphylococcus aureus (S. aureus)-infected diabetic wounds. The hydrogel incorporates copper (Cu)-doped graphitic carbon nitride (g-C₃N₄) nanosheets combined with black phosphorus (BP) nanosheets through electrostatic bonding and π-π stacking interactions, uniformly dispersed within a chitosan (CS) matrix crosslinked with polyvinyl alcohol (PVA) (Cu-CN/BP@Gel). Under NIR light irradiation, Cu-doping accelerated hot electron flow and improved the photothermal effect. Additionally, the built-in electric field formed by Cu-CN/BP accelerated interfacial electron flow and inhibited the recombination of electron-hole pairs, enhancing reactive oxygen species (ROS) generation. Then, Cu-CN/BP@Gel hydrogel can reach the antibacterial rate of 99.18% against S. aureus. The successful application of the Cu-CN/BP@Gel hydrogel in diabetic wound infection presents a new method for wound healing in a high blood sugar and ROS environment.