The effect of zinc oxide and titanium dioxide nanoparticles in the Comet assay with UVA photoactivation of human sperm and lymphocytes

Abstract

The present study has examined the effects of ZnO and TiO2 nanoparticles (40–70 nm range) in the presence and absence of UVA light in human sperm and human lymphocytes in the dark (D), after pre-irradiation with UV (PI) and simultaneous irradiation with UV (SI). For both ZnO and TiO2 nanoparticles, the percentage reduction in head DNA was greater for PI and SI samples compared with samples treated in the dark. However with regard to photogenotoxicity, sperm exhibited no significant differences when the results for PI and SI and the dark were compared, except at the lowest concentration for SI samples in the case of ZnO and the lowest concentration for PI in the case of TiO2. However for lymphocytes, responses were statistically significant at the highest concentration for both PI and SI samples. Thus, these studies suggest that there are photogenotoxic events in these cells in the absence of overt toxicity.