Current state of researches on the formation of selenium nanoparticles and their use in medicine

Due to the high interest of researchers in the problem of obtaining and applying in medicine nanoscale particles of a number of elements of both metallic and nonmetallic nature, in particular, selenium, the world scientific literature of recent years contains a significant amount of information that reflects the combination of two tops scientific trends. On the one hand, it is the development of the methodology and technologies for producing nanoscale selenium systems, and on the other, the use of their unique therapeutic properties in medicine. The aim of this work was to analyze the world scientific literature in the field of these tendencies in order to find the most effective ways to achieve specific target in the formation of selenium nanoparticles and their use in medicine, as well as the basis for obtaining new scientific and practical results in this field. The review discusses wide new possibilities for the use of selenium in medicine, including as a part of medical preparations, in the creation of new types of biosupplements, in drug delivery systems, application materials, dressings, etc., which opened up when it became possible to form it in the form of nanoparticles. They have advantages over other used forms of selenium, diffusion properties, solubility, immunogenicity and are less toxic. This allows one to optimize significantly selenotherapy and make it more effective due to, mainly, incorporation of selenium into the composition of selenoproteins and the influence on a number of biochemical processes of the body considered here. Selenium nanoparticles can also be used in new diagnostic methods and techniques for the early diagnosis of diseases. An analysis of synthesis methods is carried out: chemical reduction, biological, microwave, solvothermal / hydrothermal, “green” synthesis, electrodeposition and synthesis under the radiation of a pulsed laser. It has been shown that in the synthesis of ultrafine (including nanosized) particles of selenium with respect to therapy and its use in medicine, the principal problems are form factor of particles, size-dependence of their biological activity and vector of action; surface morphology and state of its adsorption layers, stabilization of dispersions are fundamental particles, which together are determined by the selected method. The solutions in the field of surface modification of selenium particles and stabilization of their dispersions, their use as adsorption matrices and transport systems when creating conjugates from nanoparticles and biomacromolecules are considered. Based on the analysis of the literature, as one of the conclusions of the review, an idea is drawn about the promising direction in the synthesis of nanosized particles of selenium – “green synthesis”, which is the most variable amond those considered. The materials presented in the review reflect the wide possibilities to control the processes of formation of nanosized particles of selenium(0) in accordance with the needs of developing selenotherapy. At the same time, the combination of such pathways of their formation as chemical, biological and “green synthesis” is, as for the authors, promising for the search for the latest most effective therapeutic systems both for known diseases and for those that in the near future may turn out to be objects of selenotherapy.