Titanium Dioxide Nanoparticles and the Oral Uptake-Route

AbstractTitanium dioxide (TiO2) is a common additive that is increasingly used in consumer products, food, pharmaceutical dosage forms and cosmetic articles. However, due to size reduction of TiO2 particles from the microscale to the nanoscale, application areas of this material are expanding, especially in the food sector, which makes investigations of nano-TiO2 crucial. This review focuses on two important topics of current research regarding the oral pathway: 1) anatomy of the orogastrointestinal tract, composition of epithelial and mucus layer, and pH changes; 2) cell entry mechanisms, cytotoxicity and translocation. Sufficient knowledge on the oral uptake route is not yet available but is highly needed for human risk evaluation.