Genotoxicity evaluation of titanium dioxide nanoparticles using the mouse lymphoma assay and the Ames test

• Published in: Mutation research. Genetic toxicology and environmental mutagenesis 2019-02, Vol.838, p.22-27
• Main Authors: Du, Xiuming, Gao, Shunxiang, Hong, Liling, Zheng, Xin, Zhou, Qingyun, Wu, Jihong
• Format: Article
• Language: English
• Subjects: Ames test; Gene mutation; Genotoxicity; Mouse lymphoma assay; Titanium dioxide nanoparticles
• ISSN: 1383-5718; 1879-3592
• DOI: 10.1016/j.mrgentox.2018.11.015

•The genotoxicity of Titanium dioxide nanoparticles (TiO2-NPs) was evaluated.•TiO2-NPs did not induce gene mutations in mouse lymphoma L5178Y cells.•TiO2-NPs did not induce reverse mutation in the bacterial strains..•TiO2-NPs cannot be classified as mutagenic and require further confirmatory studies. Titanium dioxide nanoparticles (TiO2-NPs) are widely used in the cosmetics, health, and food industries, but their safety and genotoxicity remain a matter of debate. We investigated whether TiO2-NPs could induce gene mutations in mouse lymphoma L5178Y cells and Salmonella typhimurium strains TA97a, TA98, TA100, TA102, and TA1535. Following preliminary tests, 2 mg/mL for the mouse lymphoma gene mutation assay and 1.25 mg/plate for the in vitro bacterial reverse mutation assay (Ames test) were selected as the highest concentrations. Exposure to TiO2-NPs for 4 or 24 h with or without S9 metabolic activation did not increase mutation frequency for any of the concentrations tested in L5178Y cells. In the Ames test, TiO2-NPs did not induce reverse mutation in the bacterial strains. No positive mutagenic responses were observed in either test system, and therefore we cannot classify TiO2-NPs as mutagenic; further testing will be required to determine conclusively whether TiO2-NPs are genotoxic.