In Situ Disinfection through Photoinspired Radical Oxygen Species Storage and Thermal‐Triggered Release from Black Phosphorous with Strengthened Chemical Stability

Abstract Photodynamic therapy (PDT) utilizing light‐induced reactive oxygen species (ROS) is a promising alternative to combat antibiotic‐resistant bacteria and biofilm. However, the photosensitizer (PS)‐modified surface only exhibits antibacterial properties in the presence of light. It is known that extended photoirradiation may lead to phototoxicity and tissue hypoxia, which greatly limits PDT efficiency, while ambient pathogens also have the opportunity to attach to biorelevant surfaces in medical facilities without light. Here, an antimicrobial film composed of black phosphorus nanosheets (BPSs) and poly (4‐pyridonemethylstyrene) endoperoxide (PPMS‐EPO) to control the storage and release of ROS reversibly is introduced. BPS, as a biocompatible PS, can produce high singlet oxygen under the irradiation of visible light of 660 nm, which can be stably stored in PPMS‐EPO. The ROS can be gradually thermally released in the dark. In vitro antibacterial studies demonstrate that the PPMS‐EPO/BPS film exhibits a rapid disinfection ability with antibacterial rate of 99.3% against Escherichia coli and 99.2% against Staphylococcus aureus after 10 min of irradiation. Even without light, the corresponding antibacterial rate reaches 76.5% and 69.7%, respectively. In addition, incorporating PPMS significantly improves the chemical stability of the BPS.