Acute and subacute toxicity of novel biogenic selenium nanoparticles in mice

CONTEXT: In the present investigation, acute and subacute toxicity of the biogenic Se nanoparticles (Se NPs) has been reported. OBJECTIVE: To characterize the Se NPs produced by a bacterium species and to evaluate their toxicity and impact on clinical chemistry and hematological parameters of NMRI mice. MATERIALS AND METHODS: The Se NPs were prepared by Bacillus sp. MSh-1 in a culture medium containing SeO(2) (1.26 mM) and their physiochemical properties investigated using TEM, XRD and FT-IR. The LD(50) of Se NPs and SeO(2) were determined and the subacute toxicity evaluated by orally administration of 0, 2.5, 5, 10 and 20 mg kg(-1) of Se NPs to male mice for 14 consecutive days. Parameters of blood cells, AST, ALT, ALP, creatinine, BUN, cholesterol, bilirubin, triglyceride and CPK were experimentally measured. RESULTS: The XRD and TEM analyses showed that the spherical NPs were amorphous, in the size range of 80-220 nm. The toxicological evaluation showed that the LD(50) values of SeO(2) and Se NPs were 7.3 and 198.1 mg kg(-1), respectively. No biochemical changes were observed from the administration of 2.5, 5 and 10 mg kg(-1) of Se NPs, but a dose of 20 mg kg(-1) was accompanied with signs of toxicity including lower body weight and changes in clinical chemistry and hematological parameters. CONCLUSION: The biogenic Se NPs were less toxic than synthetic Se NPs and much less (26-fold) toxic than the SeO(2), which demonstrates the important role of Bacillus sp. MSh-1 in conversion of a highly toxic Se compound to the less toxic Se NPs.