Radiolytic Synthesis and Characterization of Selenium Nanoparticles: Comparative Biosafety Evaluation with Selenite and Ionizing Radiation

Abstract

Selenium nanoparticles (SeNPs) were synthesized by irradiating a solution containing sodium selenite (Se+4) as the precursor in YPG liquid medium with gamma-rays. Spherical particles were formed after reactions of sodium selenite with hydrated electrons (eaq-) and hydrogen radicals (H•) produced following water radiolysis. No hazardous reducing agents were employed. The obtained nanoparticles were morphologically characterized, and their physicochemical and structural parameters were analyzed. SeNPs characterization showed all selenium in the Se0 state. We incubated Saccharomyces cerevisiae cells with the SeNPs for 24 h and then challenged the cells with ionizing radiation. After radiation exposure, cells were assessed for cell viability, lipid peroxidation, protein carbonylation, free radical generation, and total sulfhydryl content. The synthesized SeNPs were considered safe and less toxic at the concentration employed than the same selenite concentration. Except for the protein carbonylation results, there were no other significant modifications in viability or the oxidative stress parameters in SeNP-treated cells. It was concluded that 1 mM of the synthesized SeNPs does not trigger oxidative stress. Furthermore, we verified that SeNPs attenuate the reactive oxygen species generation after in vitro ionizing radiation exposure. These observations open up tremendous possibilities for radiosensitizer development.