Fig. 8.

Histogram comparisons of ion yields for characteristic biomarker ions which were used to separate the four treatment groups in Caco-2 cells (unexposed control cells (2 weeks), cells exposed to TiO₂ NMs for 2 weeks, 1 week and a washout period of 1 week). Representative biomarker ions for Caco-2 cells treated with NM-103 (a, c) and NM-104 (b, d) are presented. The biomarker ions indicate a full recovery of the cell membrane pattern to unexposed controls. For the relative intensity, the mean of the control group exposed for 2 weeks was taken as 100% in all cases