Age-dependent assessment of selenium nanoparticles: biodistribution and toxicity study in young and adult rats.

To study the biodistribution and toxicology of selenium nanoparticles (SeNPs) versus their bulk counterpart in young and adult male rats in a 28-day study. SeNPs were synthesized and conjugated with indocyanine green to assess comparative biodistribution by imaging and further characterized by transmission electron microscopy, Fourier transform infrared, scanning electron microscopy/energy dispersive x-ray spectroscopy, UV and ζ-analysis. The toxicity of bulk selenium was evaluated relative to its nano form by hematology indices, redox, inflammatory markers and histopathology. Indocyanine green-conjugated nanoparticles showed preferential accumulation in the liver, followed by testis and kidney. The protective effect of SeNPs was more significantly observed in young livers than in adults compared with the bulk counterpart. Age-dependent monitoring and diagnosis of toxicity may need different biomarkers of selenium and may also provide better understanding of SeNPs as therapeutics.