Exploring the multifaceted applications of manganese dioxide nanoparticles: Antibacterial, antibiofilm, antioxidant, and hemolytic activities

Abstract

Phase-pure α-manganese dioxide (MnO2) nanoparticles (NPs) were synthesized using an environmentally benign wet chemical redox method and evaluated for their multifunctional biological activities. Antimicrobial testing revealed significant inhibition against Gram-negative bacteria (Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris) and Gram-positive strains (Streptococcus pyogenes, Staphylococcus epidermidis, Micrococcus luteus, Staphylococcus aureus). Notable antifungal activity was observed against Candida and Aspergillus species. Antioxidant assays showed strong free radical scavenging: 95 % (DPPH), 30.25 % (ABTS), 56.85 % (nitric oxide), and 86.17 % (superoxide). MnO2 NPs also exhibited substantial antibiofilm activity against Pseudomonas aeruginosa, comparable to conventional antibiotics. Hemolysis assays confirmed their biocompatibility, with values below the cytotoxic threshold. The novelty of this study lies in its comprehensive evaluation of MnO2 NPs across five biological functionalities—antibacterial, antifungal, antibiofilm, antioxidant, and hemocompatibility—within a single experimental framework. This integrative approach advances our understanding of MnO2 NPs as versatile candidates for biomedical and environmental applications, supporting their development as safe and multifunctional agents for infection control, oxidative stress management, and future therapeutic strategies.