The Biological methods of selenium nanoparticles synthesis, their characteristics and properties

Nanotechnologies have an impact on every sphere of life, change approaches to environmental recovery, introduce new methods of disease analysis and prevention, treatment, drug delivery and gene therapy, affect the provision of environmentally friendly alternative energy sources, increase crop yields, animal and poultry productivity. Physical, chemical, biological methods of synthesis of nanoparticles, selenium in particular, their properties and the factors participating in reduction of metal ions to nanoparticles are considered. Limitations of nanoparticle synthesis inherent in the biological method (identification and isolation of bioactive fragment responsible for biomineralization of metal ions, analysis of ways to develop individual nanoparticles) and factors contributing to the intensification of nanoparticle production (optimization of pH, temperature, contact time, mixing degree) changes in the total charge of functional organic molecules on the cell wall). It has been proved that these factors affect the size, morphology, composition of nanoparticles and their efficiency during the synthesis. The model of green synthesis with the use of physicochemical means and their biomedical applications have been summarized. There are organisms used for the synthesis of NPs - terrestrial and marine bacteria, bacterial extracellular polymeric substances as bioreductants, fungi, yeast, algae, viruses, microorganisms. It has been demonstrated the biochemical ways of microorganisms in order to fight the toxicity of metals during the synthesis of nanoproducts and the factors that determine the toxicity of metals that are converted into nanoparticles (size, shape, coating agent, nanoparticle density and type of pathogen). The biological role of selenium and features of its influence on an organism in a nanoscale scale are shown. Key words: nanotechnologies, nanoselenium, bacteria, green synthesis, enzymes.