Improved extraction of intracellular biogenic selenium nanoparticles and their specificity for cancer chemoprevention

Abstract

Selenium is reported to have excellent anticancer activity at higher doses. However, due to its low therapeutic index, it is desirable to have a selenium form with lesser toxicity even at high therapeutic dose; alternatively it would be progressive to attempt efficacious preparation at very low concentration. In this study, selenium nanoparticles were synthesized biologically by Bacillus licheniformis JS2, and a method was developed for extraction and purification of intracellular nanoparticles. Characterization of extracted nanoparticles for shape, size, and purity indicated that the particles were spherical with diameters ranging between 40 and 180 nm, composed of selenium and capped with a few functional groups that provide steric stability to them. These neutral charged, non-agglomerating selenium nanoparticles at a concentration as low as 2 μg Se/mL were efficacious in inhibiting proliferation and inducing caspase independent necrosis to human prostate adenocarcinoma cells (PC3) without causing any significant toxicity to human peripheral blood mononuclear cells. © 2014 Sonkusre P, et al.