Biocompatible nanobiohybrid of maghemite nanoparticle-coated probiotics: A synergistic platform for enhanced antibacterial, antibiofilm, and antioxidant activities

The rise in free radical species and bacterial infections accelerates biofilm formation, impeding wound healing and leading to severe complications, thereby posing a significant global threat to public health. In this study, we synthesized a novel nanobiohybrid material by coating maghemite nanoparticles (γ-Fe₂O₃ NPs) onto the surface of Lactobacillus rhamnosus (LR) probiotics to address bacterial infections, inhibit biofilm formation, and scavenge free radicals. The γ-Fe₂O₃ NPs-LR nanobiohybrid was characterized using PXRD, FTIR, XPS, TEM, FESEM, zeta potential analysis, and UV-Vis spectroscopy, confirming the successful interaction between the γ-Fe₂O₃ NPs and LR. The antibacterial activity of the nanobiohybrid at 1000 μg mL^-1 was assessed by measuring the zone of inhibition against L. monocytogenes (15.17 ± 0.29 mm), S. succinus (12.83 ± 0.29 mm), S. thompson (5.33 ± 0.29 mm), and E. coli O157:H7 (7.67 ± 0.29 mm), revealing significantly higher inhibitory effects compared to γ-Fe₂O₃ NPs and LR alone. Antibiofilm assays demonstrated the nanobiohybrid's superior ability to inhibit and disrupt established biofilms. Additionally, the antioxidant potential was evaluated using the DPPH scavenging assay, which showed enhanced scavenging activity (66.57 ± 0.53% at 500 µg mL^-1). Importantly, cytotoxicity studies on mouse embryonic fibroblast (MEF) and human intestinal (Caco-2) cell lines confirmed that the nanobiohybrid exhibits excellent biocompatibility at relevant concentrations. This study demonstrates that the γ-Fe₂O₃ NPs-LR nanobiohybrid is a promising biocompatible synergistic platform for diverse biomedical applications, including infection control, wound healing, and oxidative stress management.