Exposure of Caco-2 Cells to TiO2 Particles

Human colon adenocarcinoma cell line Caco-2 (Toni Lindl, Munich, Germany) between passage 24 and 50 were cultured in Caco-2 medium (45% Dulbecco’s Modified Eagle Medium (DMEM), low glucose, 45% Ham’s F12, 9% fetal calf serum (FCS), 0.9% non-essential amino acids) (all PAA Laboratories GmbH, Austria), and insulin (10 µg mL⁻¹) (Biochrome AG, Berlin, Germany) at 37 °C and 5% CO₂. For all experiments cells were seeded at a density of 1× 10⁵–2 × 10⁵ cells cm⁻². TiO₂ particles were added to the cells at a final concentration of 40 µg cm⁻² cell growth surface as this concentration is in accordance with the observed exposure in humans [2 (link)] and in the range of other comparable references [3 (link),5 (link),18 (link),58 (link)]. We determined the time we exposed the cells to NPs prior to the described experiments by a number time course analyses.