Ag-Activated Metal-Organic Framework with Peroxidase-like Activity Synergistic Ag⁺ Release for Safe Bacterial...

Silver nanoparticles (Ag NPs), a commonly used antibacterial nanomaterial, exhibit broad-spectrum antibacterial activity to combat drug-resistant bacteria. However, the Ag NPs often causes a low availability and high toxicity to living bodies due to their easy aggregation and uncontrolled release of Ag⁺ in the bacterial microenvironment. Here, we report a porous metal-organic framework (MOF)-based Zr-2-amin-1,4-NH₂-benzenedicarboxylate@Ag (denoted as UiO-66-NH₂-Ag) nanocomposite using an in-situ immobilization strategy where Ag NPs were fixed on the UiO-66-NH₂ for improving the dispersion and utilization of Ag NPs. As a result, the reduced use dose of Ag NPs largely improves the biosafety of the UiO-66-NH₂-Ag. Meanwhile, after activation by the Ag NPs, the UiO-66-NH₂-Ag can act as nanozyme with high peroxidase (POD)-like activity to efficiently catalyze the decomposition of H₂O₂ to extremely toxic hydroxyl radicals (·OH) in the bacterial microenvironment. Simultaneously, the high POD-like activity synergies with the controllable Ag⁺ release leads to enhanced reactive oxygen species (ROS) generation, facilitating the death of resistant bacteria. This synergistic antibacterial strategy enables the low concentration (12 μg/mL) of UiO-66-NH₂-Ag to achieve highly efficient inactivation of ampicillin-resistant Escherichia coli (Amp^rE. coli) and endospore-forming Bacillus subtilis (B. subtilis). In vivo results illustrate that the UiO-66-NH₂-Ag nanozyme has a safe and accelerated bacteria-infected wound healing.