In Situ Structure Transformation of a Sprayed Gel for pH‐Ultrasensitive Nano‐Catalytic Antibacterial Therapy

Abstract Nano‐catalytic bacterial killing provides new opportunities to address ever‐increasing antibiotic resistance. However, the intrinsic catalytic activity usually depends on a much lower pH conditions (pH = 2–5) than that in the weakly acidic bacterial microenvironments (pH = 6–7) for reactive oxygen species production by Fenton reactions. Herein, a MnSiO 3 ‐based pH‐ultrasensitive “in situ structure transformation” is first reported to significantly promote the adhesion between material and bacteria, and shorten the diffusion distance (<20 nm) to compensate ultra‐short life (<200 ns) of ·OH generated by Mn 2+ ‐mediated Fenton‐like reaction, finally enhancing its nano‐catalytic antibacterial performance in weakly acidic conditions. A separated spray bottle is further designed to achieve in situ gelation at the wound site, which demonstrates excellent shape adaptability to complicated and rough surfaces of wounds, allowing for long‐term nano‐catalyst release. As a result, bacterial‐infected wound healing is efficiently promoted. Herein, the in situ sprayed nano‐catalytic antibacterial gel presents a promising paradigm for bacterial infection treatment.