Assessing the Cytotoxicity of TiO2−x Nanoparticles with a Different Ti3+(Ti2+)/Ti4+ Ratio

• DOI: 10.1007/s12011-022-03403-3
• Publication Date: 2022-08-27T06:05:01Z
• Authors: Volodymyr Prokopiuk; Svetlana Yefimova; Anatolii Onishchenko; Valeriy Kapustnik; Valeriy Myasoedov; Pavel Maksimchuk; Dmytro Butov; Irina Bespalova; Anton Tkachenko
• Keywords: Titanium; Microscopy, Electron, Transmission; Cell Survival; Animals; Nanoparticles; Metal Nanoparticles; Fibroblasts; Rats

Abstract Titanium dioxide (TiO2) nanoparticles are promising biomedical agents characterized by good biocompatibility. In this study, we explored the cytotoxicity of TiO2-x nanoparticles with a different Ti3+(Ti2+)/Ti4+ ratio and analyzed the effeciency of eryptosis indices as a tool in nanotoxicology. Methods. Two types of TiO2-x nanoparticles (5 nm) with various Ti3+ (Ti2+)/ Ti4+ ratios in the crystal lattice were synthesized. 1-TiO2-x nanoparticles contained 54% Ti4+, 38% Ti3+ and 8% Ti2+, while the relative amount of Ti4+ and Ti3+ in the crystal lattice of 2-TiO2-x nanoparticles was 63% and 37%, respectively. Cell viability and cell motility induced by TiO2-x nanoparticles were investigated on primary fibroblast cultures. Eryptosis modulation by the nanoparticles along with cell death mechanisms was studied on rat erythrocytes.Results. We report that both TiO2-x nanoparticles don’t decrease the viability of fibroblasts simultaneously stimulating cell migration. Data from in vitro studies on erythrocytes indicate that TiO2-x nanoparticles trigger eryptosis via ROS- (1-TiO2-x) and Ca2+-mediated mechanisms (both TiO2-x nanoparticles) suggesting that evaluation of eryptosis parameters is a more sensitive nanotoxicological approach for TiO2-x nanoparticles than cultured fibroblast assays.Conclusion. TiO2-x nanoparticles are characterized by low toxicity against fibroblasts, but they induce eryptosis, which is shown to be a promising tool for nanotoxicity screening. The Ti3+ (Ti2+)/ Ti4+ ratio at least partially determines the cytotoxicity mechanisms for TiO2-x nanoparticles.