Surface-engineered MnO₂@Au@ZIF-67 hierarchical catalysts for acid-triggered antibacterial therapy and infected wound healing

Rational surface engineering of nanocatalysts offers new solutions against antibiotic-resistant infections. We designed and fabricated hierarchical MnO₂@Au@ZIF-67 nanoparticles (NPs) with triple interfacial functionalities for synergistic antibacterial therapy. The acid-responsive ZIF-67 surface degrades in infected wounds, releasing Co²⁺ to catalyze •OH generation via Fenton-like reactions at the material-bacteria interface. Simultaneously, ultrasmall Au surfaces deplete glucose through oxidase-mimetic catalysis, producing gluconic acid that accelerates ZIF-67 dissolution. The MnO₂ core surface decomposes H₂O₂ to supply O₂, enhancing Au catalysis and alleviating hypoxia. Comprehensive surface characterization (TEM, SEM, XPS, XRD) confirmed structural integrity and reactive sites. In vitro, the NPs achieved > 99 % bacterial killing (S. aureus/E. coli) through ROS-mediated membrane disruption (validated by SEM/CLSM). In vivo, they enabled 98.45 % bacterial clearance and accelerated wound healing via collagen reorganization (H&E/Masson staining). This surface-engineered platform demonstrates how interfacial catalytic cascades can be harnessed for effective non-antibiotic antimicrobial applications.