Identification of titanium dioxide nanoparticles in food products: Induce intracellular oxidative stress mediated by TNF and CYP1A genes in human lung fibroblast cells

Abstract Food grade TiO 2 (E171) is a synthetic additive, and widely used as a coloring agent in many foods, pharmaceutical and personal care products. A few reports have highlighted that insoluble particulates (less than 200 nm) of food grade TiO 2 are found in many foods and confectionary products. However, information regarding the physico-chemical properties (i.e., size and shape)-based food grade TiO 2 nanotoxicity related human health issues are limited. The main goal of this study is to examine the presence of nano-sized particulates and its structural characteristics of food grade- TiO 2 materials and to assess the acute cellular uptake and metabolic stress induced by these particulates in human lung fibroblast (WI-38) cells. The results of transmission electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction studies indicated that about food grade TiO 2 sample contains spherical shaped particulate forms in the nano-scale range,  S > G0/G1) and changes in the TNF and CYP1A gene expression pattern are linked to cellular stress. Thus, food grade TiO 2 as nano-scaled contaminants could not only be potential human health risk factors, suggesting that safety considerations with special respect to a few crucial factors such as size, and shape should be considered and regulated by food regulators.