Antioxidant and Anticancer Activities of Bio-Synthesized Selenium Nanoparticles by Escherichia coli

Selenium, an essential micronutrient, plays a crucial role in various physiological processes, including immune function, fertility, and the prevention of chronic diseases like diabetes, cardiovascular disease, and certain cancers. While selenium nanoparticles (SeNPs) have garnered significant attention for their potential in cancer therapy, their biosynthesis using eco-friendly methods remains a key area of research.

In this study, Escherichia coli isolates were utilized to biosynthesize SeNPs from sodium selenite (25, 50, and 100 mM) at pH 8 and 160 rpm for 48 hours. The biosynthesized  SeNPs were characterized using Fourier Transform Infrared Spectroscopy (FTIR), UV-Visible spectroscopy, X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM). The antioxidant and anti-proliferative activities of the synthesized SeNPs were evaluated against human colorectal carcinoma (SW480), human hepatocellular carcinoma (HepG2), and normal human embryonic kidney (HEK293) cell lines.

The biosynthesis process resulted in a reddish-brown coloration of the medium, indicating the formation of SeNPs. Characterization techniques confirmed the successful synthesis of SeNPs with a size range of 21.96-50.71 nm. The SeNPs exhibited significant antioxidant activity, with a maximum radical scavenging efficiency of 80.21% at a concentration of 100 µg/ml. Additionally, the SeNPs demonstrated potent anti-proliferative effects against both SW480 and HepG2 cell lines, with IC50 values of 3.9 and 4.5 µg/ml, respectively. Importantly, the SeNPs exhibited negligible cytotoxicity towards normal HEK293 cells.

The eco-friendly biosynthesis of SeNPs using E. coli offers a promising approach for producing nanoparticles with potential applications in biomedical fields. The synthesized SeNPs demonstrated potent antioxidant and anti-cancer properties, suggesting their potential as a novel therapeutic agent.