A review on applications and toxicities of metallic nanoparticles in mammalian semen biology.

The advent of nanotechnology since the 1950s, when the well-known physicist Richard P. Feynman talked in his famous talk about "There's plenty of room at the bottom", has led to incredible contribution of nanotechnology in the fields of medical and veterinary therapeutics, diagnostics and other applications. Semen biology dealing with the study of spermatozoa and its related physiological and pathological aspects has not remained unscathed from the facets of nanotechnology. With each passing day investigators are revealing newer aspects of the nanoparticles, such as an antioxidants to relieve oxidative stress during semen cryopreservation, for the depletion of moribund spermatozoa from semen, gender selection of spermatozoa, bio-imaging of gametes, sperm mediated gene transfer, as well as for male fertility evaluation. As, the uses of various magnetic nanoparticles in the industry have gained acceleration, the evaluation of their effects, either beneficial or otherwise on the mammalian spermatozoa becomes obligatory. Many toxicological studies have also been conducted in respect to the harmful effects of different metallic nanoparticles related to their applicability, and industry borne adverse effects on the male germ cells in human beings and the animals. This review has been designed to focus on the beneficial as well as toxicological effects of various metallic nanoparticles on the mammalian spermatozoa and the future prospects related to their applicability in the semen biology.