Preparation, Physicochemical Characterization, and In Vitro Biological Properties of Selenium Nanoparticle Synthesized from Exopolysaccharide of Enterococcus faecium MC-5

The selenium nanoparticles (SeNPs) linked with exopolysaccharide (EPS) of E. faecium MC-5 were successfully produced. UV–Vis spectra, DLS, zeta potential, SEM, TEM, FT-IR, thermogravimetric analysis-DSC, and X-ray diffraction measurements were used to characterize the SeNPs in terms of formation, size, stability, and functional group attachment, morphology, distribution, and phase. The spectral resonance of SeNPs was validated by seeing a peak at 383 nm in UV-Vis, demonstrating their synthesis. The SeNPs conjugated to EPS were found to be amorphous and well distributed in the size range of 76 nm. The interactions between the –OH groups of EPS and SeNPs have resulted in new C–O–Se bonds and excellent SeNP scattering distribution in the EPS matrix. The SeNPs were found to have good thermal stability (a strong resistance to thermal processes over 245 °C). The SeNPs displayed good antimicrobial properties with different pathogens at various concentrations. This work not only reveals the critical role of EPS as a biocompatible polymer template for SeNP dispersion, stability, and size control but also acts as an effective antioxidant against DPPH, and hydroxyl radicals and also showed better antibiofilm properties. SeNPs also had a greater survival rate of up to 100 μg/mL in the in vivo study and had no cytotoxicity on larvae of Artemia salina . Hence, the potential SeNPs act as a unique contender to tackle the biofilm challenge in aquaculture sectors and can be implemented in the medical and cosmetic industries.