Enhanced Antibacterial and Anti-Biofilm Activity of Green-Synthesized Silibinin-Functionalized Silica-Coated Fe₃O₄ Nanocomposites Against Staphylococcus aureus
Subject Areas : Biotechnological Journal of Environmental MicrobiologyNazanin Pasandideh Kordmahaleh 1 , Mirsasan Mirpour 2 , Mahdi Shariarinour 3 * , Najmeh Ranji 4 , Mohammad Nikpassand 5
1 - Department of Microbiology, La.C., Islamic Azad University, Lahijan, Iran
2 - Department of Microbiology, La.C., Islamic Azad University, Lahijan, Iran
3 - Department of Biology, Ra.C., Islamic Azad University, Rasht, Iran
4 - Department of Biology, Ra.C., Islamic Azad University, Rasht, Iran
5 - Department of Chemistry, Ra.C., Islamic Azad University, Rasht, Iran
Keywords: Silibinin, Green synthesis , Magnetic nanocomposite, Staphylococcus aureus , Vancomycin synergy , Biofilm inhibition,
Abstract :
Silibinin, a bioactive flavonolignan derived from Silybum marianum, possesses notable antibacterial, antioxidant, and hepatoprotective properties; however, its poor aqueous solubility restricts clinical applications. In this study, silibinin-functionalized silica-coated magnetic nanocomposites (Fe₃O₄@SPN@Silibinin) were synthesized via a green synthesis route to enhance solubility, stability, and antibacterial performance. The nanocomposites were comprehensively characterized using FTIR, TEM, FE-SEM, XRD, TGA, and VSM analyses, confirming uniform morphology (34–58 nm), high thermal stability, and ferromagnetic behavior with a saturation magnetization of approximately 30 emu/g. Antibacterial evaluation against Staphylococcus aureus (ATCC 25923 and clinical isolates) demonstrated potent inhibitory effects, particularly when combined with vancomycin. Checkerboard assays revealed a strong synergistic interaction, with a 4–16-fold reduction in the minimum inhibitory concentrations (MICs) of both agents. Furthermore, the combination significantly inhibited biofilm formation and accelerated bacterial killing, as confirmed by time-kill kinetics. These findings indicate that Fe₃O₄@SPN@Silibinin nanocomposites substantially enhance the antibacterial efficacy of vancomycin and effectively suppress biofilm-associated resistance mechanisms. The results highlight the promise of this green-synthesized nanoplatform as an efficient adjuvant strategy for managing multidrug-resistant S. aureus infections.
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