Traditional selenium supplements are usually highly toxic and have low levels of absorption, so developing systems that are using selenium compounds as a carrier to increase the bioavailability of the element and control its release in the body is extremely important. Nano-sized selenium is of great interest as a dietary supplement, especially in selenium-deficient states, as well as as a therapeutic agent without significant adverse effects. Emphasis is placed on the incorporation of nanotechnological applications, the study of an effective route of administration, and generalized knowledge about selenium nanoparticles, their biological effects and advantages, and mechanisms of absorption. Nanotechnical modifications of nanoparticles, the use of SeNPs as a nutritional supplement, and the effects they exert on the body are considered. Various methods for the synthesis of SeNPs are considered. The study focuses on the problems of traditional forms of dietary selenium and the benefits of SeNPs. The mechanisms of nanoparticles passage through the intestinal mucosa and the features of their oral administration are elucidated. The presented materials prove that the importance of Selenium lays on regulation in the composition of selenoproteins of many physiological processes, influence on the productive and reproductive properties. Correction of selenium content in the diet prevents a number of selenium deficiency diseases, and selenium in nano form is most appropriate for use because of its high bioavailability and low toxicity, which is especially relevant for ruminants. Further preclinical and clinical studies in vitro and in vivo will enable the development of novel nanopreparative systems for transport in selenium, alter the physicochemical properties of SeNPs, increase their stability in the gastrointestinal tract for controlled release of the element to provide dietary and therapeutic benefits.

Key words: nanoparticles, selenium, biomedicine, oxidative stress, biomedical application of nanoparticles.