Figure 2From: Comparison of the killing effects between nitrogen-doped and pure TiO2 on HeLa cells with visible light irradiationMMP of HeLa cells as a function of the time after the PDT. Cells were incubated with 100 μg/ml TiO2 (white square) or N-TiO2 (black circle) for 2 h and illuminated by the visible light for 5 min. The averaged fluorescence intensity of control cells (white triangle) at 0 min was set as 100%.Back to article page