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

• Published in: Biological trace element research 2023-06, Vol.201 (6), p.3117-3130
• Main Authors: Prokopiuk, Volodymyr, Yefimova, Svetlana, Onishchenko, Anatolii, Kapustnik, Valeriy, Myasoedov, Valeriy, Maksimchuk, Pavel, Butov, Dmytro, Bespalova, Irina, Tkachenko, Anton
• Format: Article
• Language: English
• Subjects: Analytical methods; Biochemistry; Biocompatibility; Biomedical and Life Sciences; Biotechnology; Calcium ions; Cell death; Cell migration; Cell viability; Crystal lattices; Crystal structure; Cytotoxicity; Electron microscopy; Erythrocytes; Fibroblasts; Hydrolysis; Life Sciences; Nanoparticles; Nitric acid; Nitric acids; Nutrition; Oncology; Parameter sensitivity; Photoelectron spectroscopy; Photoelectrons; Surgical implants; Synthesis; Titanium; Titanium dioxide; Toxicity; Transmission electron microscopy; X ray photoelectron spectroscopy
• ISSN: 0163-4984; 1559-0720
• DOI: 10.1007/s12011-022-03403-3

Titanium dioxide (TiO 2 ) nanoparticles are promising biomedical agents characterized by good biocompatibility. In this study, we explored the cytotoxicity of TiO 2− x nanoparticles with a different Ti 3+ (Ti 2+ )/Ti 4+ ratio and analyzed the efficiency of eryptosis indices as a tool in nanotoxicology. Two types of TiO 2− x nanoparticles (NPs) were synthesized by the hydrolysis of titanium alkoxide varying the nitric acid content in the hydrolysis mixture. Transmission electron microscopy (TEM) images show that 1-TiO 2− x and 2-TiO 2− x NPs are 5 nm in size, whereas X-ray photoelectron spectroscopy (XPS) reveals different Ti 3+ (Ti 2+ )/Ti 4+ ratios in the crystal lattices of synthesized NPs. 1-TiO 2− x nanoparticles contained 54% Ti 4+ , 38% Ti 3+ , and 8% Ti 2+ , while the relative amount of Ti 4+ and Ti 3+ in the crystal lattice of 2-TiO 2− x nanoparticles was 63% and 37%, respectively. Cell viability and cell motility induced by TiO 2− x nanoparticles were investigated on primary fibroblast cultures. Eryptosis modulation by the nanoparticles along with cell death mechanisms was studied on rat erythrocytes. We report that both TiO 2− x nanoparticles do not decrease the viability of fibroblasts simultaneously stimulating cell migration. Data from in vitro studies on erythrocytes indicate that TiO 2− x nanoparticles trigger eryptosis via ROS- (1-TiO 2− x ) and Ca 2+ -mediated mechanisms (both TiO 2− x nanoparticles) suggesting that evaluation of eryptosis parameters is a more sensitive nanotoxicological approach for TiO 2− x nanoparticles than cultured fibroblast assays. TiO 2− 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 Ti 3+ (Ti 2+ )/Ti 4+ ratio at least partly determines the cytotoxicity mechanisms for TiO 2− x nanoparticles.