Inactivation of mammalian spermatozoa on the exposure of TiO(2) nanorods deposited with noble metals

Titanium dioxide (TiO(2)) nanorods (NRs) are well-known semiconducting and catalytic material that has been widely applied, but their toxicities have also attracted recent interest. In this study, we investigated and compared the toxic effects of TiO(2) NRs and TiO(2) NRs loaded with Ag or Au NPs on boar spermatozoa. As a result, sperm incubated with Ag-TiO(2) NRs showed lower motility than sperm incubated with controls (with or without TiO(2) NRs) or Au-TiO(2) NRs. In addition, sperm viability and acrosomal integrity were defective in the presence of Ag-TiO(2) NRs, and the generation of intracellular reactive oxygen species (ROS) increased significantly when spermatozoa were incubated with 20 μg/ml Ag-TiO(2) NRs. We discussed in depth the charge transfer mechanism between enzymatic NADPH and Ag-TiO(2) NRs in the context of ROS generation in spermatozoa. The effects we observed reflected the fertilization competence of sperm incubated with Ag-TiO(2) NRs; specifically sperm penetration and embryonic development rates by in vitro fertilization were reduced by Ag-TiO(2) NRs. To summarize, our findings indicate that exposure to Ag-TiO(2) NRs could affect male fertilization fecundity and caution that care be exercised when using these NRs.