Synthesis of ZIF-8 Coated MnO₂ Functionalized Antibacterial Peptide Nanoparticles and Its Antibacterial and...

Antibiotics, a milestone invention in modern medicine, have significantly improved human quality of life and serve as a primary weapon against bacterial infections. However, antibiotic abuse has led to the emergence and worsening of bacterial resistance, now a major global public health challenge. Therefore, the efficient use of nanoscale antimicrobial peptides (APs) as therapeutic and diagnostic agents offers a novel strategy to replace conventional antibiotics. In this study, we innovatively combined AP with manganese dioxide (MnO₂) and zeolitic imidazolate framework-8 (ZIF-8) to develop a novel composite: ZIF-8-encapsulated and AP-loaded MnO₂ (AP-MnO₂@ZIF-8). This composite exhibited superior properties, including enhanced biocompatibility, excellent aqueous stability, and increased antibacterial activity. Both in vitro and in vivo AP-MnO₂@ZIF-8 demonstrated potent efficacy against multidrug-resistant (MDR) Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Its minimum inhibitory concentrations (MICs) were 20 μg/ml for E. coli and 39 μg/ml for S. aureus. Furthermore, colony-forming unit (CFU) assays showed that 150-μg/ml AP-MnO₂@ZIF-8 reduced bacterial survival below 5%, indicating effective growth inhibition. Crucially, it significantly suppressed bacterial activity in S. aureus-infected mouse wound models. Compared to free AP or MnO₂ alone, AP-MnO₂@ZIF-8 showed significantly enhanced water solubility, bioavailability, and antibacterial activity. This work provides a foundation for developing AP-based antimicrobial strategies and offers a novel nanomaterial approach to combat the increasingly severe antibiotic resistance crisis.