Facile synthesis of a CeMnOx catalytic gel with bacterial microenvironment-responsive antibacterial properties

Abstract

A nanocatalytic antimicrobial gel responsive to the bacterial infection microenvironment (IME) possessing highly specific antimicrobial properties provides an opportunity to address the bacterial drug resistance. However, the pH conditions and low substrate concentration in the IME limit the catalytic antimicrobial efficiency of these agents, resulting in unsatisfactory performance. The reported transition metal peroxide alleviates endogenous substrate insufficiency due to H₂O₂ self-supplying properties, but still suffers from difficulties of simple synthesis, long-stem storage and lower intrinsic catalytic efficiency responsive to the IME. In this paper, we report for the first time the use of cerium–manganese bimetallic peroxide nanoparticles (CeMnOx) as a nanocatalyst with high pH responsiveness, H₂O₂ self-supplying properties, multiple ROS-generating activity and synergistic effect-enhanced cascade catalytic reactions for efficient antimicrobial therapy. CeMnOx achieved more than 95% kill rate at 50 μg mL⁻¹ for E. coli and 100 μg mL⁻¹ for S. aureus, which was superior to those of previously reported works. To further improve the availability, nanoparticle-carrying hydrogels with excellent antimicrobial properties were prepared through in situ gelation, thus adapting to a wider range of antimicrobial application scenarios. Therefore, the in situ molded nanocatalytic antimicrobial gels provide a promising paradigm for efficient treatment of bacterial infections.