In situ generation of peroxynitrite (ONOO^-) for enhanced antibacterial photodynamic therapy

Antibacterial photodynamic therapy (PDT) as a valuable strategy to combat bacteria is always limited by its short lifespan, high oxygen dependence, and narrow therapeutic distance of the singlet oxygen generated through a Type-II reaction. Herein, we construct a photodynamic antibacterial nanoplatform (PDP@NORM) to produce oxygen-independent peroxynitrite (ONOO-) for achieving enhanced photodynamic antibacterial efficacy through the co-assembly of a nitric oxide (NO) donor and a porphyrin-based amphiphilic copolymer. ONOO- could be generated by the reaction of a superoxide anion radical (O-2(center dot-)) from the Type-I photodynamic process of porphyrin units with NO from the NO donor in PDP@NORM. The in vitro and in vivo experiments proved that PDP@NORM showed high antibacterial efficiency, resisting wound infection and speeding up wound healing after simultaneous irradiation with 650 nm and 365 nm light. Therefore, PDP@NORM may provide a new insight into the design of an efficient antibacterial strategy.