2026/07/01 by Nidhi Chandrakar, Dugeshwar Karley, Sudhir K. Shukla
paper · doi:10.1111/apm.70239
ABSTRACT In this study, we report the eco‐friendly synthesis of silver nanoparticles (AgNPs) using cell‐free supernatant of Staphylococcus saprophyticus as a biological reducing and stabilising agent. Nanoparticle formation was confirmed by visible colour change and UV–visible spectroscopy ( λ max at 418 nm). Structural characterisation by SEM, XRD and FT‐IR indicated predominantly spherical, crystalline, silver‐containing nanoparticles associated with extracellular biomolecules that may contribute to stabilisation; XRD analysis indicated a surface phase dominated by silver halides (AgBr/AgCl) rather than confirming a purely metallic Ag 0 lattice. The biosynthesised AgNPs exhibited strong antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa , with minimum inhibitory concentrations of 3 and 0.5 μg/mL, respectively. Significant antifungal activity was also observed against Candida albicans , with marked growth suppression at 100 μg/mL. The AgNPs effectively reduced biofilm formation, extracellular matrix production and virulence traits. DCFH‐DA fluorescence and MTT assays showed increased reactive oxygen species generation and reduced cellular metabolic activity in treated microbes, suggesting oxidative stress‐associated antimicrobial effects. Cytotoxicity testing indicated low toxicity towards HeLa cells at lower concentrations, with dose‐dependent effects observed only at higher exposure levels. Overall, results demonstrate that biogenic AgNPs possess antibacterial, antifungal and antibiofilm properties, highlighting their potential as sustainable and eco‐friendly antimicrobial candidates.