Facile synthesis of selenium nanoparticles and stabilization using exopolysaccharide from endophytic fungus, Nigrospora gullinensis, and their bioactivity study

The primary objective of this work was to investigate the synthesis and the bioactivity of SeNPs encapsulated with exopolysaccharide (EPS). The EPS was mainly composed of 395 ± 13.20 mg/g carbohydrate and 121 ± 3.21 mg/g protein; the following moiety was used for surface stabilization of selenium nanoparticles (SeNPs). Bioactive SeNPs, i.e., EPS-SeNPs, with an average size of 43.7 ± 13.7 nm, were successfully synthesized. The antibacterial bioactivity of EPS-SeNPs was seen to be enhanced against Gram-positive bacteria, viz., Bacillus subtilis, Staphylococcus aureus, and Enterococcus faecalis, as well as Gram-negative bacteria, such as Escherichia coli and Salmonella enterica. In addition, the study also demonstrated antifungal activity against Alternaria alternata, Fusarium laterium, and Aspergillus niger. The cytotoxic activity of synthesized EPS-SeNPs exhibited a dose-dependent response against liver carcinoma cell lines, i.e., the HepG2. These findings support the hypothesis that these nanoparticles hold potential as an emerging material in the field of therapeutics.