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

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 condition (pH = 2 ∼ 5) than that in the weakly acidic bacterial microenvironment (pH = 6 ∼ 7) for reactive oxygen species production by Fenton reactions. Herein, a MnSiO 3 -based pH-ultrasensitive "in situ structure transformation" was 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 condition. A separated spray bottle was further designed to achieve in situ gelation at wound site, which demonstrates excellent shape adaptability to complicated and rough surface of wounds, allowing for long-term nano-catalyst release. As a result, bacterial-infected wound healing has been efficiently promoted. Our in situ sprayed nano-catalytic antibacterial gel presents a promising paradigm for bacterial infection treatment. This article is protected by copyright. All rights reserved.