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Study on the visible-light-induced photokilling effect of nitrogen-doped TiO2 nanoparticles on cancer cells.

Li Z, Mi L, Wang PN, Chen JY - Nanoscale Res Lett (2011)

Bottom Line: However, the visible-light-induced photokilling effects on cells were observed.The survival fraction of the cells decreased with the increased incubation concentration of the nanoparticles.The reactive oxygen species was found to play an important role on the photokilling effect for cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China. lanmi@fudan.edu.cn.

ABSTRACT
Nitrogen-doped TiO2 (N-TiO2) nanoparticles were prepared by calcining the anatase TiO2 nanoparticles under ammonia atmosphere. The N-TiO2 showed higher absorbance in the visible region than the pure TiO2. The cytotoxicity and visible-light-induced phototoxicity of the pure- and N-TiO2 were examined for three types of cancer cell lines. No significant cytotoxicity was detected. However, the visible-light-induced photokilling effects on cells were observed. The survival fraction of the cells decreased with the increased incubation concentration of the nanoparticles. The cancer cells incubated with N-TiO2 were killed more effectively than that with the pure TiO2. The reactive oxygen species was found to play an important role on the photokilling effect for cells. Furthermore, the intracellular distributions of N-TiO2 nanoparticles were examined by laser scanning confocal microscopy. The co-localization of N-TiO2 nanoparticles with nuclei or Golgi complexes was observed. The aberrant nuclear morphologies such as micronuclei were detected after the N-TiO2-treated cells were irradiated by the visible light.

No MeSH data available.


Related in: MedlinePlus

Changes in the surviving fractions of the TiO2-treated HeLa cells with histidine. The concentration of the three TiO2 samples is 200 μg/mL and L-histidine is 20 mM.
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Figure 4: Changes in the surviving fractions of the TiO2-treated HeLa cells with histidine. The concentration of the three TiO2 samples is 200 μg/mL and L-histidine is 20 mM.

Mentions: The mechanism of the photokilling effect for cancer cells caused by TiO2 nanoparticles is very complex. It has been identified that UV-photoexcited TiO2 in aqueous solution will result in formation of various ROS, such as hydroxyl radicals (·OH), hydrogen peroxide (H2O2), superoxide radicals (·O2-) and singlet oxygen (1O2) [19,20]. The ROS will attack the cancer cells and finally lead to the cell death. In order to study the function of ROS on the photokilling effect, the L-histidine, a quencher for both 1O2 and ·OH [21-23], was added into the 96-well plates (20 mM) 30 min before the cells were irradiated by light. In the presence of 20 mM L-histidine, all the surviving fractions of the cells treated with pure- and N-TiO2 at a concentration of 200 μg/mL increased evidently as shown in Figure 4. These results are similar to the previous report for UV-photoexcited TiO2 [14]. It can be concluded that the ROS plays an important role on the photokilling effect, although we cannot tell which one played the main role. Further research is needed to figure out all the ROS influences.


Study on the visible-light-induced photokilling effect of nitrogen-doped TiO2 nanoparticles on cancer cells.

Li Z, Mi L, Wang PN, Chen JY - Nanoscale Res Lett (2011)

Changes in the surviving fractions of the TiO2-treated HeLa cells with histidine. The concentration of the three TiO2 samples is 200 μg/mL and L-histidine is 20 mM.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211446&req=5

Figure 4: Changes in the surviving fractions of the TiO2-treated HeLa cells with histidine. The concentration of the three TiO2 samples is 200 μg/mL and L-histidine is 20 mM.
Mentions: The mechanism of the photokilling effect for cancer cells caused by TiO2 nanoparticles is very complex. It has been identified that UV-photoexcited TiO2 in aqueous solution will result in formation of various ROS, such as hydroxyl radicals (·OH), hydrogen peroxide (H2O2), superoxide radicals (·O2-) and singlet oxygen (1O2) [19,20]. The ROS will attack the cancer cells and finally lead to the cell death. In order to study the function of ROS on the photokilling effect, the L-histidine, a quencher for both 1O2 and ·OH [21-23], was added into the 96-well plates (20 mM) 30 min before the cells were irradiated by light. In the presence of 20 mM L-histidine, all the surviving fractions of the cells treated with pure- and N-TiO2 at a concentration of 200 μg/mL increased evidently as shown in Figure 4. These results are similar to the previous report for UV-photoexcited TiO2 [14]. It can be concluded that the ROS plays an important role on the photokilling effect, although we cannot tell which one played the main role. Further research is needed to figure out all the ROS influences.

Bottom Line: However, the visible-light-induced photokilling effects on cells were observed.The survival fraction of the cells decreased with the increased incubation concentration of the nanoparticles.The reactive oxygen species was found to play an important role on the photokilling effect for cells.

View Article: PubMed Central - HTML - PubMed

Affiliation: Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Department of Optical Science and Engineering, Fudan University, Shanghai 200433, China. lanmi@fudan.edu.cn.

ABSTRACT
Nitrogen-doped TiO2 (N-TiO2) nanoparticles were prepared by calcining the anatase TiO2 nanoparticles under ammonia atmosphere. The N-TiO2 showed higher absorbance in the visible region than the pure TiO2. The cytotoxicity and visible-light-induced phototoxicity of the pure- and N-TiO2 were examined for three types of cancer cell lines. No significant cytotoxicity was detected. However, the visible-light-induced photokilling effects on cells were observed. The survival fraction of the cells decreased with the increased incubation concentration of the nanoparticles. The cancer cells incubated with N-TiO2 were killed more effectively than that with the pure TiO2. The reactive oxygen species was found to play an important role on the photokilling effect for cells. Furthermore, the intracellular distributions of N-TiO2 nanoparticles were examined by laser scanning confocal microscopy. The co-localization of N-TiO2 nanoparticles with nuclei or Golgi complexes was observed. The aberrant nuclear morphologies such as micronuclei were detected after the N-TiO2-treated cells were irradiated by the visible light.

No MeSH data available.


Related in: MedlinePlus