Nanoparticles are particles with a diameter of less than 100 nm in at least one dimension and are widely used because of their small size. An increasing number of bio-resistant nanomaterials with a high surface area to volume ratio are exhibiting pronounced pathogenic, mainly genotoxic effects, manifesting in inflammation, fibrosis and cancer. The genotoxic effects and potential cancer formation depend on the shape, size and type of nanoparticles, but their impact on cancer formation is not yet fully understood. Asbestos fibres are already classified as carcinogens, while the pathological effects on biological systems of titanium dioxide nanoparticles and carbon-based nanoparticles have not yet been definitively identified. It has been reported that the first early defects that can be caused by asbestos fibres are the formation of micronuclei and multinucleated cells, which are associated with genomic instability and, consequently, the development of aneuploidy – an abnormal number of chromosomes in a cell. To detect early changes in lung epithelial cell division, we exposed cells to different nanoparticles, namely titanium dioxide nanoparticles in the form of nanotubes, titanium dioxide nanoparticles in the form of nanocubes and multiwalled carbon nanotubes, and observed the changes with a confocal fluorescence microscope over several hours and several days in a time-course experiment on live cells. The experiments showed an increased number of multinucleated and micronucleated cells in cells exposed to nanoparticles, which were accompanied by nuclear deformation in cells exposed to nanoparticles. We also observed prolonged mitosis time in cells exposed to nanoparticles of titanium dioxide nanotubes and multiwalled carbon nanotubes, suggesting abnormalities in the cell division process. All the abnormalities observed are associated with a defect in cytokinesis, the final stage of cell division in which the primary cell finally divides into two daughter cells. Although the results did not unequivocally confirm that the observed pathologies are exclusively due to nanoparticles, we hypothesise that certain nanoparticles may influence and alter key cellular processes and morphological properties. In vitro experiments have also shown the diversity of the impact of nanoparticles with different physicochemical properties on cells, which requires further research to better understand the mechanisms of interaction at the cellular level.
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