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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 SeO2 (1.26 mM) and their physiochemical properties investigated using TEM, XRD and FT-IR. The LD50 of Se NPs and SeO2 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 LD50 values of SeO2 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 SeO2, which demonstrates the important role of Bacillus sp. MSh-1 in conversion of a highly toxic Se compound to the less toxic Se NPs.