Figure 1
The ToxTracker reporter assay for mechanism-based toxicity testing . (A) The ToxTracker assay consists of a panel of GFP-based mES cell lines. The GFP reporters indicate activation of the Nrf2-associated antioxidant response, ATR-associated DNA damage response and the p53 cellular stress response. Induction of the GFP reporters as well as cytotoxicity is determined by flow cytometry. (B) Cellular uptake but no evidence for nuclear localization of metal oxide NPs in mES cells. Internalization of the NPs after 24 h exposure to 20 μg/mL CuO, 30 μg/mL ZnO, 100 μg/mL NiO, 100 μg/mL CeO2 and 10 μg/mL Ag-10 NPs was determined by means of TEM. NPs were taken up by mES cells and were localized in endosomal vesicles or free in the cytoplasm (black arrow heads).