Reactivity Differences Enable ROS for Selective Ablation of Bacteria

Abstract An effective strategy to engineer selective photodynamic agents to surmount bacterial‐infected diseases, especially Gram‐positive bacteria remains a great challenge. Herein, we developed two examples of compounds for a proof‐of‐concept study where reactive differences in reactive oxygen species (ROS) can induce selective ablation of Gram‐positive bacteria. Sulfur‐replaced phenoxazinium ( NBS‐N ) mainly generates a superoxide anion radical capable of selectively killing Gram‐positive bacteria, while selenium‐substituted phenoxazinium ( NBSe‐N ) has a higher generation of singlet oxygen that can kill both Gram‐positive and Gram‐negative bacteria. This difference was further evidenced by bacterial fluorescence imaging and morphological changes. Moreover, NBS‐N can also successfully heal the Gram‐positive bacteria‐infected wounds in mice. We believe that such reactive differences may pave a general way to design selective photodynamic agents for ablating Gram‐positive bacteria‐infected diseases.