Selenium nanoparticles: synthesis, characterization and study of their cytotoxicity, antioxidant and antibacterial activity

This report concerns the green synthesis of selenium nanoparticles (Se-NPs) through chemical reduction method using ascorbic acid (Vitamin C) as a reluctant and polyvinyl alcohol (PVA) or chitosan (CS) as stabilizers. Ultraviolet-visible (UV-vis) absorption spectroscopy, dynamic light scattering (DLS), fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM) were applied as the main characterization tools. The cytotoxicity of Se-NPs on fibroblast L929 cells was determined by MTT assay. The nanoparticles showed low toxicity toward the investigated cell line which remained more than 50% viable at 170 ppm for 24 h. The in-vitro antioxidant property of the synthesized Se nanoparticles was evaluated by radical scavenging (DPPH) assay. The IC50 values of the nanoparticles were 26.56 and 530 ppm for PVA coated SeNPs (PVA-SeNPs) and CS coated SeNPs (CS-SeNPs), respectively. Finally, the antibacterial activity of Se-NPs was determined on the gram-negative bacteria Escherichia coli, Pseudomonas aeruginosa, and the gram positive bacteria Staphylococcus aureus, Streptococcus epidermidis. The results showed that Se nanoparticles exhibited dose-dependent antibacterial activity against all the four bacterial strains tested. Noticeably, PVA-SeNPs exhibited significant effect against S. epidermidis (MIC 125 ppm) and S. aureus (MIC 125 ppm). The results of this study indicate that Se nanoparticles can be potentially used as antimicrobial and antioxidant agents.