MMP 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%.
Li et al. Nanoscale Research Letters 2013 8:96 doi:10.1186/1556-276X-8-96