The widespread use of nanomaterials is rapidly being implemented in various fields of economic activity, including biology and medicine. There is a wealth of information on the toxicity and various manifestations of the biological effects of nanomaterials, such as fullerenes, carbon nanotubes, zinc oxide, aluminum oxide, cerium oxide, gold, iron, iron oxide, silver, cobalt, lanthanum, lead, and others, in scientific literature and electronic information sources. However, during the planning stage of the dissertation research, information on the toxic properties of nanopowders based on titanium dioxide obtained by thermal decomposition of metatitanic acid, as well as for nanocomposite materials of titanium dioxide with silver, was limited or completely absent. The toxic effects of metal nanoparticles are associated with their nanoscale size and high surface activity, allowing them to penetrate cells and interact with biological structures. This can lead to the generation of reactive oxygen species, oxidative stress, DNA damage, disruption of cell membranes, impairment of organ and tissue function, inflammation and immunotoxicity, as well as the development of long-term consequences such as cancer, neurotoxicity, reproductive disorders, and other negative effects.
Promising nanomaterials are those based on titanium dioxide with high photocatalytic activity, which are used for the degradation of organic pollutants, disinfection, creation of antimicrobial and self-cleaning surfaces. The photocatalytic activity of TiO2 nanoparticles can be significantly enhanced by modifying titanium dioxide nanoparticles with a certain amount of silver nanoparticles (nano-TiO2-Ag). At the I.M. Frantsevich Institute for Problems of Material Science of the National Academy of Sciences of Ukraine, nanopowders based on titanium dioxide are synthesized using an original method, namely the thermal decomposition of metatitanic acid.
The issue of ensuring the safe production and use of nanomaterials is relevant for human health and environmental preservation. During the production of TiO2 and TiO2-Ag nanopowders, there is a risk of workers inhaling air in the work area contaminated with dust particles in the ultra-microscopic and nanoscale ranges, as well as their contact with clothing, skin, and mucous membranes. The lack of comprehensive knowledge about the toxicity of nanomaterials and their potential hazards to the human body requires conducting appropriate hygienic, toxicological, medical, and biological research.
The aim of the dissertation research was to study the peculiarities of the toxic effects of titanium dioxide nanopowders and titanium dioxide-silver nanocomposite in experiments on laboratory animals, in vitro models, and to provide scientific justification for measures to prevent their potential adverse effects on the body of synthesis operators, including determining the approximate safe levels of exposure to these nanomaterials in the air of the work area.
The dissertation addresses the solution to the relevant scientific problem of occupational hygiene and preventive medicine in relation to preventing the adverse effects of titanium dioxide nanopowders and titanium dioxide-silver nanocomposite on the health of synthesis operators.
Hygienic assessment of the technological process and environmental factors in the production of new titanium dioxide nanopowders and titanium dioxide-silver nanocomposite was conducted for the first time using the thermal decomposition method of metatitanic acid in a multi-section rotary kiln at the I.M. Frantsevich Institute for Materials Science of the National Academy of Sciences of Ukraine. A special method was developed to detect ultra- and nanoscale fractions of particles in the air of the work area, which allowed for the stabilization and suspension of nanoparticles in a glucose-citrate buffer during air sampling in the work area and subsequent analytical investigations. We obtained a patent for a useful model, No. 148325, for the «Method of Stabilizing Metal Nanopowders and their Derivatives with a Glucose-Citrate Buffer», which has practical significance. It was established that the specific and potentially hazardous factor in the synthesis process of TiO2 and TiO2-Ag nanopowders using the thermal decomposition method of metatitanic acid in a multi-section rotary kiln is the aerosol of ultra- and nanoscale titanium dioxide particles, detected by laser granulometry during the synthesis of TiO2 nanopowder at the operator's workstation near the control panel, with a dominant fraction ranging from 19,5 nm to 38,91 nm. The titanium content in the air of the work area was determined using optical emission spectroscopy, ranging from 0,13 to 3,3 µg/m3.
