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.

中文翻译：

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使用小鼠淋巴瘤试验和Ames试验评估二氧化钛纳米颗粒的遗传毒性。

二氧化钛纳米颗粒（TiO2-NPs）被广泛用于化妆品，保健和食品行业，但其安全性和遗传毒性仍是一个有争议的问题。我们调查了TiO2-NPs是否可以在小鼠淋巴瘤L5178Y细胞和鼠伤寒沙门氏菌菌株TA97a，TA98，TA100，TA102和TA1535中诱导基因突变。在初步测试之后，选择2 mg / mL进行小鼠淋巴瘤基因突变测定，并将1.25 mg /板进行体外细菌反向突变测定（Ames试验）作为最高浓度。在L5178Y细胞中测试的任何浓度下，暴露于TiO2-NPs的4或24小时，无论是否具有S9代谢激活，都不会增加突变频率。在Ames测试中，TiO2-NPs不会在细菌菌株中诱导反向突变。在任一测试系统中均未观察到阳性诱变反应，因此我们不能将TiO2-NPs归为致突变物。需要进一步测试以确定TiO2-NP是否具有遗传毒性。