Biologically synthesized selenium nanoparticles from cell-free supernatant of Lysinibacillus odysseyi with therapeutic potential.

Recent research on the biosynthesis of nanoparticles with bacteria has increased due to their eco-friendly approaches, and the delivery of drugs to targeted cells through nanoparticles has also increased. This study describes the biosynthesis of selenium nanoparticles from the cell-free supernatant of Lysinibacillus odysseyi (PP112153). Characterization through UV-Vis spectroscopy shows a peak at 279 nm. FT-IR indicates that the reduction and stabilization of Se ions to SeNPs were caused by the presence of functional groups in the CFS. Zeta potential shows -70.1 mV (indicating more stability), particle size at 85.8 nm, and XRD indicates a crystalline nature with a peak index of 29.45°. The biological activities of SeNPs were examined through antioxidant assays, with maximum percentage inhibition at 10 μg/ml by DPPH (81.51 %), phosphomolybdate antioxidant (83.79 %), nitric oxide (NO) radical scavenging (69.91 %), and FRAP assay showing higher values at 2 μg/ml (OD at 0.51). The antibacterial activity shows the highest zone of inhibition at 10 μg/ml against E. hormaechei (28 mm), and for antibiofilm activity, the maximum percentage inhibition was observed at 100 μg/ml for S. saccharolyticus (85.7 %), with significant inhibition. Anti-inflammatory activity was highest at 100 μg/ml, with a percentage identified as 78.36 %, showing notable results. Toxicity analysis revealed mortality in a dose-dependent manner, with an LC50 value of 775 μg/ml for 48 h, indicating significant compatibility and low toxicity. Selenium nanoparticles were biosynthesized for the first time using the cell-free supernatant (CFS) of L. odysseyi, demonstrating significant biological activities and requiring further exploration for therapeutic applications.