Distribution of silver nanoparticles in pregnant mice and developing embryos.

The objective of this study was to evaluate the distribution of silver nanoparticles (NPs) in pregnant mice and their developing embryos. Silver NPs (average diameter 50 nm) were intravenously injected into pregnant CD-1 mice on gestation days (GDs) 7, 8, and 9 at dose levels of 0, 35, or 66 μg Ag/mouse. Mice were euthanised on GD10, and tissue samples were collected and analysed for silver content. Compared with control animals injected with citrate buffer vehicle, silver content was significantly increased (p < 0.05) in nearly all tissues from silver NP-treated mice. Silver accumulation was significantly higher in liver, spleen, lung, tail (injection site), visceral yolk sac, and endometrium compared with other organs from silver NP-treated mice. Furthermore, silver NPs were identified in vesicles in endodermal cells of the visceral yolk sac. In summary, the results demonstrated that silver NPs distributed to most maternal organs, extra-embryonic tissues, and embryos, but did not accumulate significantly in embryos.