Fig. 3.

Ion reconstructions of a 3D depth profile of Caco-2 cells exposed to TiO₂ nanoparticles at a concentration of 3.13 µg/cm² (NM-103: A–C, NM-104: D–F) for 1 week (A, D), 2 weeks (B, E) and for 1 week with a 1 week recovery period (C, F). Cell outlines are shown in solid blue and were reconstructed from the C3H8N + signal from phosphatidylcholine, and intracellular TiO₂ NMs are shown in green