Selenium nanoparticle production using Azadirachta indica extract: biosynthesis, characterization, and cytotoxic effects in fibroblast cells.

Selenium nanoparticles (SeNPs) have attracted considerable attention in biomedical research owing to their potent antioxidant, antimicrobial, and anticancer properties, along with their reduced toxicity. The current paper set out to prepare SeNPs under Azadirachta indica (Neem) leaf extract, to describe their physicochemical characteristics, and to determine their cytotoxic action on a normal fibroblast cell line. The synthesized SeNPs were systematically characterized using UV-visible spectrophotometry, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), Transmission Electron microscopy (TEM), SAED pattern and X-ray diffraction (XRD) analyses. The average crystallite size of the nanoparticles was calculated using the Scherrer equation. The antioxidant efficacy was demonstrated the ABTS and nitric oxide scavenging analysis, Cytotoxicity evaluation was carried out through an MTT assay using L929 fibroblast cells exposed to a concentration range of selenium nanoparticles from 10-100 µg/mL. SEM imaging showed the heterogeneous morphology, irregular, and aggregated structures and the size of the nanoparticles is 2.3 nm at TEM analysis. FTIR spectra showed the occurrence of the phenolic, amide, and alcohol functional groups that were involved in the capping of the particles. X-ray diffraction analysis confirmed that the synthesized nanoparticles possessed a predominantly crystalline nature, with an average crystallite size of 27.6 nm. The MTT assay demonstrated a concentration-dependent response, showing greater than 90% cell viability at concentrations up to 40 mg/mL, while a moderate reduction in viability (approximately 75%) was observed at 100 mg/mL.