Synthesis of selenium-containing galactomannan-stabilized nanocomposites with particle size-sensitive antiradical activi

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1979

Synthesis of selenium-containing galactomannan-stabilized nanocomposites with particle size-sensitive antiradical activity M. V. Lesnichaya,a A. N. Sapozhnikov,b and B. G. Sukhova aA.

E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences, 1 ul. Favorskogo, 664033 Irkutsk, Russian Federation. Fax: +7 (395 2) 41 9346. E-mail: [email protected] bA. P. Vinogradov Institute of Geochemistry, Siberian Branch, Russian Academy of Sciences, 1a ul. Favorskogo, 664033 Irkutsk, Russian Federation Water-soluble hybrid nanocomposites were synthesized for the first time with the use of industrial crystalline selenium (gray powder selenium) activated in a hydrazine hydrate—alkali base-recovery system. The obtained nanocomposites consist of the selenium nanoparticles 13.0—24.0 nm in size stabilized by biocompatible natural polysaccharide galactomannan. The structures of the nanocomposites were characterized by a complex of physicochemical methods (X-ray diffraction analysis, transmission electron microscopy, and infrared spectroscopy). The pronounced antioxidant activity of the prepared nanocomposites against free radicals of 2,2-diphenyl-1-picrylhydrazyl and 2,2´-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt was found, and its value correlates with the particle size of selenium. Key words: nanoparticles, selenium, nanocomposite, galactomannan, radical, antiradical activity.

It is well known that selenium is an essential element,1 being a component of a series of selenoproteins that perform a whole complex of vitally important functions in the organisms, among which the function of antioxidant protection of cells from a number of reactive oxygen species plays a special role. Reactive oxygen species are permanently synthesized in cells as a result of both natural exchange processes and (in enhanced amounts) the interaction of the cell with pathogenic agents (viruses, microbes, and toxins), as well as in the case of inflammatory factors and factors of tumor growth and destruction.2 Selenium deficient in the organism is accompanied by the development of a number of heavy diseases, such as exudative diathesis. diseases of thyroid gland, liver necrosis, and Keshan and Kashin—Beck diseases.3 Therefore, preventive measures toward selenium deficiency are very important. The high toxicity of inorganic forms of selenium and very high reactivity of selenomethionine and other selenium-containing organic compounds leading to cell damage restrict the possibility of biological application of these compounds and stimulate the search for less toxic selenium sources.4 An alternative at present is the use of zero-valent selenium nanoparticles (NP-Se0). According to a series of studies, NP-Se0 are characterized by low toxicity along with high biological, in particular, antioxidant, activity5,6 dependent on the particle size. The NP-Se0 suitable for biological application can be produced directly from powdered zero-valent gray selenium (cheap

and available chemical precursor) using natural hete