Comparison of the killing effects between nitrogen-doped and pure TiO2 on HeLa cells with visible light irradiation
1 Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Department of Optical Science and Engineering, Shanghai Ultra-Precision Optical Manufacturing Engineering Center, Fudan University, 220 Handan Road, 200433, Shanghai, China
2 State Key Laboratory of Surface Physics, Department of Physics, Fudan University, 220 Handan Road, 200433, Shanghai, China
Nanoscale Research Letters 2013, 8:96 doi:10.1186/1556-276X-8-96Published: 22 February 2013
The killing effect of nitrogen-doped titanium dioxide (N-TiO2) nanoparticles on human cervical carcinoma (HeLa) cells by visible light photodynamic therapy (PDT) was higher than that of TiO2 nanoparticles. To study the mechanism of the killing effect, the reactive oxygen species produced by the visible-light-activated N-TiO2 and pure-TiO2 were evaluated and compared. The changes of the cellular parameters, such as the mitochondrial membrane potential (MMP), intracellular Ca2+, and nitrogen monoxide (NO) concentrations after PDT were measured and compared for N-TiO2- and TiO2-treated HeLa cells. The N-TiO2 resulted in more loss of MMP and higher increase of Ca2+ and NO in HeLa cells than pure TiO2. The cell morphology changes with time were also examined by a confocal microscope. The cells incubated with N-TiO2 exhibited serious distortion and membrane breakage at 60 min after the PDT.