Figure 1

Treatment with ZnO, TiO ₂ , and FeO did not activate caspase-3 or caspase-9. A, HT29-SCAT3 cells were treated with different nanoparticles as indicated (ZnO 10 = 10 μg/ml, ZnO 20 = 20 μg/ml, TiO₂ 10 = 10 μg/ml, TiO₂ 30 = 30 μg/ml, TiO₂ 100 = 100 μg/ml, FeO 10 = 10 μg/ml, FeO 30 = 30 μg/ml, FeO 100 = 100 μg/ml). Staurosporine (STS = 1 μM) was used as a positive control to induce caspase-3 activation. The images were analyzed using an automated ImageXpress Micro microscope at 20× magnification. The changes in the emission ratio after treatment and exposure to 435 nm light (530 nm ECFP/475 nm Venus) were measured as described by Takemoto et al. 2003 and quantitated using the MetaXpress software. This experiment was repeated 3 times. B, HT29-SCAT9 cells were treated with different nanoparticles as indicated (ZnO 10 = 10 μg/ml, ZnO 20 = 20 μg/ml, TiO₂ 10 = 10 μg/ml, TiO₂ 30 = 30 μg/ml, TiO₂ 100 = 100 μg/ml, FeO 10 = 10 μg/ml, FeO 30 = 30 μg/ml, FeO 100 = 100 μg/ml). Staurosporine (STS = 1 μM) was used as a positive control to induce caspase-9 activation. The images were analyzed using an automated ImageXpress Micro microscope at 20× magnification. The changes in the emission ratio after treatment and exposure to 435 nm light (530 nm ECFP/475 nm Venus) were measured as described by Takemoto et al. 2003 and quantitated using the MetaXpress software. This experiment was repeated 3 times.