The ecotoxicology of titanium dioxide nanoparticles, an important engineering nanomaterial

Titanium dioxide nanoparticles (nano-TiO2) are useful because of their unique physicochemical properties. The wide application of nano-TiO2 has raised concerns regarding its potential threat to organisms and the environment. Therefore, the production and application of nano-TiO2 in the global market is summarized in this paper. This review presents the adverse effects of nano-TiO2 in vivo, including potential exposure routes such as transdermal, oral and inhalative exposure, risk evaluation of nanotoxicity in vitro using bacteria, microorganisms, cells and biological molecules), physicochemical characterization of nano-TiO2 regarding crystal structure, size, shape, surface characteristics and coatings, and the mechanisms of toxicity of nano-TiO2 based on environmentally relevant test species and cells. This review aims to fill deficiencies in toxicological research and to facilitate the assessment of the environmental risks by nano-TiO2 which is conducive to designing safer nanoproducts in our daily life.