Sulfur Vacancy‐Rich Bi2S3‐X@PDA Heterojunctions with Light‐Controlled Reactive Oxygen Species Generation and Elimination to Combat Biofilm Infection and Inflammation Caused by Drug‐Resistant Bacteria

Abstract Antibacterial photocatalytic therapy (APCT) is one of the most promising non‐antibiotic treatment strategies for biofilm‐infected wounds and inflammation caused by drug‐resistant bacteria. However, it still faces issues such as inadequate single antibacterial capacity and lack of antioxidant capacity. In this study, a Z‐scheme heterojunction (Bi 2 S 3‐X @PDA) is designed using a polydopamine (PDA) shell firmly anchored to the surface of sulfur vacancy‐rich bismuth sulfide nanorods (Bi 2 S 3‐X NRs). Under near‐infrared light and hydrogen peroxide, Bi 2 S 3‐X @PDA significantly improves the photocatalytic efficiency of reactive oxygen species generation and shows a nearly 100% broad‐spectrum antibacterial effect against multiple bacterial strains and bacterial biofilms in vitro. Interestingly, the antioxidant activity of the PDA shell in Bi 2 S 3‐X @PDA remarkably downregulates the expression of pro‐inflammatory factors and promotes macrophage reprogramming toward the proregenerative M2 phenotype. In a mouse wound model of methicillin‐resistant Staphylococcus aureus biofilm infection, Bi 2 S 3‐X @PDA effectively eliminates drug‐resistant bacterial biofilms through APCT/mild photothermal therapy, while reducing inflammation in normal tissues and regulating the immune microenvironment, thereby promoting rapid wound healing. Overall, this light‐controlled treatment strategy, which provides both antibacterial and anti‐inflammatory functions, is a reliable tool for combating biofilm infection and inflammation caused by drug‐resistant bacteria.