Semicomducting TiO2, TiN Nanomaterials ECOTOXICITY. Enhanced environmental and microbiological assessment

The analysis of domestic and foreign scientific sources and electronic information bases has been shown that the development of technical and technological issues in nanosciences significantly outstrips the decision of medical and biological and medical-preventive tasks of protecting human and environmental elements from the potential harmful effects of nanoparticles. Like other toxicants, nanoparticles, in particular, low-melt oxygen-free refractory metal compounds, can enter the human body by inhalation, percutaneous and oral routes. They are capable of spreading in the human body, not only penetrating through the plasma membrane of cells and overcoming natural biological barriers, but also along the nerve fibers - perineurally

The goal: To reveal the peculiarities of toxic effects TiO2, TiN nanopowders on living organisms. The important tasks: 1. Dispersity and morphological features of TiO2, TiN nanopowders. 2. Cytotoxicity of investigated nanopowders. 3. Morphological changes in the internal organs of animals
We report that very interesting oxide can be TiO2 of pure anatase modification as carrier of high concentration OH * radicals because of: 1.Active participation can also take quantum-size effects due to the Mott-Wannier exciton radius, which can vary in the range of 0.8-1.9 nm, depending on the particle size of TiO2. 2. In TiO2 anatase particles with a size of 10 nm, the electron exit time to the surface does not exceed 10 pcs, ​​whereas direct electron-hole recombination in crystals of a number of semiconductors, including titanium dioxide, is characterized by τrec of about 100 ns. 3. Interfacial electron transfer to adsorbed substrates occurs on average in 50–200 pcs.
 

Сonclusions
1. Experimental the toxic influence of synthesized nanopowders TiO2, TiN on virus and living organisms (animals) was stated. 2. It was shown no effect toxicity of TiO2 anatase on MDBK (bull liver cells). The greatest ingibition of Adenovirus becomes 90-95% with contact of synthesized TiO2 anatase in comparison with P25 Evonic. 3. TiN nanopowders at the mean mortality dose when injected into the stomach of mice (> 5000 mg/kg) are classified as hazard classes 4 (low hazard) according to GOST 12.1.007-76 "Harmful substances. Classification and general safety requirements. " They have a weakly irritating effect on the mucous membranes of the rabbit and do not irritate the skin of guinea pigs and rabbits. 4. One-time intranasal intercalation  of nano-TiN in rats leads to structural changes in the bronchial tree and respiratory lung unit: after 1 day and 7 days, the titanium nitride nanoparticles were detected in part of the alveoli, changes in the structural organization of the cells appeared to be damaged by the aerogematous barrier. 5. Maximal permit concentration is 0.53 mg/m3 for TiN nanopowder.

Zahornyi M.N. Nanodispersed powders as fillers of photoactive composites. Review. // Powder metallurgy. - 2017. - №3-4. - C.1-28.

Zahornyi M.N. Functional nanocomposites based of titanium dioxide// Lambert Academic Publishing.-2018. - P.157(ISBN : 978-613-8-27486-5)