Toxicity of nanoparticles embedded in paints compared to pristine nanoparticles, in vitro study

The unique physicochemical properties of nanomaterials has led to an increased use in the paint and coating industry. In this study, the in vitro toxicity of three pristine ENPs (TiO2, Ag and SiO₂), three aged paints containing ENPs (TiO₂, Ag and SiO₂) and control paints without ENPs were compared. In a first experiment, cytotoxicity was assessed using a biculture consisting of human bronchial epithelial (16HBE14o-) cells and human monocytic cells (THP-1) to determine subtoxic concentrations. In a second experiment, a new coculture model of the lung-blood barrier consisting of 16HBE14o- cells, THP-1 and human lung microvascular endothelial cells (HLMVEC) was used to study pulmonary and extrapulmonary toxicity. The results show that the pristine TiO₂ and Ag ENPs have some cytotoxic effects at relative high dose, while pristine SiO₂ ENPs and all aged paints with ENPs and control paints do not. In the complex triculture model of the lung-blood barrier, no considerable changes were observed after exposure to subtoxic concentration of the different pristine ENPs and paint particles. In conclusion, we demonstrated that although pristine ENPs show some toxic effects, no significant toxicological effects were observed when they were embedded in a complex paint matrix.