SELENIUM IN NANOFORM: TOXICITY AND SAFETY

Abstract

The review is devoted to the compilation of data on the toxicity and safety of using nanosized forms of selenium. It is shown that in nature selenium exists mainly in the form of selenate (Se6+), selenite (Se4+), selenide (Se2–) and elemen-tal selenium (Se0), while the latter is insoluble in aqueous media, less toxic and biologically inert. Elemental selenium in the form of nanosized particles is not only biocompatible, but also has antitumor and antimicrobial activity. It was shown that elemental selenium in the form of nanoparticles can modulate the activity of the antioxidant and detoxification systems. A data on the dose-dependent effect of selenium in nanosized form was presented. It was demonstrated that selenium nanoparticles in high concentrations (above 2 mg of Se per 1 kg of animal weight) can cause the development of selenium-induced toxicity in mammals. It was shown that elemental selenium in the form of nanoparticles can affect immunoregulation, reproductive func-tion, kidney and liver function, can modulate the activity of the antioxidant and detoxification systems, and in high concentrations (above 2 mg of Se per 1 kg of animal weight) it can cause the development of selenium-induced toxicity both in mammals and fish. At the same time, it was shown that for fish selenium nanoparticles are more toxic than inorganic selenium and cause a more acute reaction of the body to exposure to even low concentrations, which is possibly associated with hyperaccumulation of selenium in tissues. This fact once again reminds us of the need to take into account the problems of ecotoxicity of selenium nanocomposites.