Green biosynthesis of bimetallic silver iron oxide nanoparticles using sclerotinia sclerotiorum and their antimicrobial and anticancer potential
Abstract
Bimetallic nanoparticles often exhibit enhanced physicochemical and biological properties compared with their monometallic counterparts. This study aimed to develop an environmentally friendly fungal-mediated synthesis of silver–iron oxide nanoparticles (Ag-FeONPs) using the phytopathogenic fungus Sclerotinia sclerotiorum and to evaluate their physicochemical characteristics, antimicrobial activity, and in vitro cytotoxicity. Ag-FeONPs were biosynthesized using fungal biomass and characterized by UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), scanning and transmission electron microscopy (SEM/TEM), energy-dispersive X-ray analysis (EDX), dynamic light scattering (DLS), and zeta potential analysis. Their antimicrobial activity was evaluated against Escherichia coli , methicillin-resistant Staphylococcus aureus (MRSA), and Candida albicans . Cytotoxicity was assessed against MCF-7 breast cancer cells and MCF-10A normal breast epithelial cells. UV-Vis spectroscopy confirmed nanoparticle formation with a characteristic surface plasmon resonance peak at 416 nm. FTIR analysis indicated that fungal biomolecules participated in nanoparticle reduction and stabilization. DLS analysis showed a narrow particle size distribution (Z-average: 22.3 ± 1.1 nm; PDI: 0.2881 ± 0.006), while the positive zeta potential (+29.95 ± 1.03 mV; n = 3) indicated good colloidal stability. The Ag-FeONPs exhibited moderate antibacterial activity against E. coli, no detectable activity against MRSA, and strong antifungal activity against C. albicans. The nanoparticles also produced dose-dependent inhibition of MCF-7 breast cancer cells with comparatively lower toxicity toward MCF-10A cells. However, the calculated selectivity index indicated limited cancer-cell selectivity. These findings demonstrate that fungal-mediated Ag-FeONPs possess antimicrobial and cytotoxic activities under in vitro conditions. Although the nanoparticles showed promising biological activity, their limited selectivity toward cancer cells indicates that further mechanistic investigations and in vivo studies are required to validate their therapeutic potential.