Evaluation of the biological fate and the transport through biological barriers of nanosilver in mice.

Nanosilver (nAg) is a considerably important nanomaterial due to its unique physical and chemical features and its intrinsic antimicrobial properties. Thus far, nAg has been widely applied in a variety of fields including biomedicine. Considering the safety and adverse influence, investigations into the biological fate and potential toxicity of nAg are essential for its safe and appropriate applications. In the current study, we exposed nAg to BALB/c mice at various concentrations via intraperitoneal (IP) and intravenous (IV) routes. The results showed that nAg was predominantly localized in liver and spleen in mice for both administration methods. Compared to IP administration, nAg was quickly removed and excreted from body with IV administration. The accumulation of nAg in livers caused remarkable hepatic toxicity. For the first time, we demonstrated that nAg had the ability to cross the placental barrier and accumulate in fetuses. Furthermore, the results of nAg tissue distribution in male mice revealed that nAg could pass through the blood-testis barrier, resulting in localization in testis. Additionally, the pharmacokinetic process of nAg in mice was also assessed in this study. Our findings indicated that nAg retention in mouse body could last for more than 4 months, and the silver content in the major recipient organs decreased in a time-dependent manner. Taken together, these results would be of great assistance in clarifying the safety issue of nAg as drug delivery and therapeutic agent, and in the understanding of the mechanisms underlying nAg-meditated toxicity.