TiO2 nanoparticles induce endothelial cell activation in a pneumocyte-endothelial co-culture model

► An epithelial-endothelial co-culture model to evaluate the effect of nanoparticles was developed. ► TiO2 nanoparticles induced activation of endothelial cells when the epithelial cells were exposed. ► Adhesion of monocytes to the endothelial cells was observed after 3 h of exposure. ► Increases in the expression of adhesion molecules correlated with the adhesion of monocytes.