In vitro effect of gold and silver nanoparticles on human spermatozoa.

The cytotoxicity of Au/Ag nanoparticles (NPs) on human spermatozoa was investigated in vitro. Semen from donors were incubated (37 °C, 60'-120') with 30, 60, 125, 250 and 500 μM Au/Ag-NPs. Sperm motility was evaluated following WHO guidelines; sperm viability was assessed with eosin Y test. Au-NPs were characterised and localised with field emission gun-based scanning transmission electron microscope/energy dispersive spectroscopy and transmission electron microscopy. Both tested NPs exerted a significant dose-dependent effect on motility and viability of human spermatozoa (P < 0.001). Ag-NPs seem to show a slightly elevated toxicity although not significant (P > 0.05). Au-NPs were localised in spermatozoa, whereas Ag-NPs were undetectable. In conclusion, Au-NPs and Ag-NPs do not appear to be harmful for human spermatozoa up to high concentrations (250-500 μM) that are probably difficult to reach in vivo. It is mandatory to explore the genotoxic effect of NPs in germ cells.