A certain amount of MMP loss (around 24%) was followed by the detectable increase of Ca2+ (at 5 and 15 min after the PDT for N-TiO2 and TiO2, respectively). The increase of NO was detected find more later than the other intracellular parameters, which indicates that the NO generation was caused by the generation of ROS. The N-TiO2 resulted in more loss of MMP and higher increase of Ca2+ and NO in
HeLa cells and, finally, induced more cell damages than pure TiO2. At 60 min after irradiation, significant cytoskeletal shrinkage and breakage were observed for N-TiO2-treated cells, whereas for TiO2-treated cells, only slight damage was demonstrated. Overall, N-TiO2 can induce more cell damages than pure TiO2. The hydroxyl radicals might contribute less to the cell damages among a variety of ROS.
Acknowledgments This work is supported by the National Natural Science Foundation of China (61008055, 11074053), the Ph.D. Programs Foundation of Ministry of Education of China (20100071120029), and the Key Subjects Innovative Talents Training Program of Fudan University. Electronic supplementary material Additional file 1: Figure S1: Absorbance spectra of TiO2 and N-TiO2 nanoparticles. Description: A shoulder was observed at the edge of the absorption spectra, which extended the absorption of N-TiO2 from 380 nm to 550 nm. (TIFF 776 KB) Additional file 2: Figure S2: The transmission spectrum of the 400 to 440 nm bandpass filter. Description: The PKC inhibitor filter could transmit some light with the wavelength below 400 nm, which could be of absorbed by the pure TiO2 as shown in
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