Nanoengineered γ MnO₂ Accelerates the Degradation of Antibiotic-Resistant Biofilms

Bacterial biofilms remain a major challenge in clinical infections due to their dense extracellular polymeric substance (EPS) matrix and strong resistance to conventional antibiotics. This study reports manganese dioxide (MnO₂) nanoparticles capable of autonomous navigation toward bacterial clusters, mechanical penetration of biofilm structures, redox-driven membrane disruption, and synergistic oxidative stress. The nanoparticles exhibit directional movement attributed to a combination of negatively charged surface potential, asymmetric topology, and catalytic reactivity toward bacterial metabolites. MnO₂ demonstrates potent antibiofilm activity against MRSA and MDR E. coli (>98% eradication) and partial activity against Pseudomonas aeruginosa. Time-lapse microscopy, EPR spectroscopy, XPS analysis, and SEM imaging reveal that MnO₂ disrupts both EPS and cell membranes while maintaining structural integrity throughout treatment. Cytotoxicity assays confirm ≥85% viability in human fibroblasts and keratinocytes at therapeutic concentrations. MnO₂ shows controlled biodegradation into Mn²⁺ ions, which participate in physiological pathways and undergo renal clearance. These findings support MnO₂ nanoparticles as promising biofilm-targeting agents for topical formulations, wound care, and implant coatings.