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Fluorescence characteristics and lifetime images of photosensitizers of talaporfin sodium and sodium pheophorbide a in normal and cancer cells.

Awasthi K, Yamamoto K, Furuya K, Nakabayashi T, Li L, Ohta N - Sensors (Basel) (2015)

Bottom Line: The reduction of the fluorescence intensity by photoirradiation was observed for both photosensitizers in both cells, but the quenching rate was much faster in cancer cells than in normal cells.These results are explained in terms of the excessive generation of reactive oxygen species via photoexcitation of these photosensitizers in cancer cells.The fluorescence lifetimes of both photosensitizers in cancer cells are different from those in normal cells, which originates from the different intracellular environments around the photosensitizers between normal and cancer cells.

View Article: PubMed Central - PubMed

Affiliation: Research Institute for Electronic Science (RIES), Hokkaido University, Sapporo 001-0020, Japan. kaawasthi@gmail.com.

ABSTRACT
Fluorescence spectra and fluorescence lifetime images of talaporfin sodium and sodium-pheophorbide a, which can be regarded as photosensitizers for photodynamic therapy, were measured in normal and cancer cells. The reduction of the fluorescence intensity by photoirradiation was observed for both photosensitizers in both cells, but the quenching rate was much faster in cancer cells than in normal cells. These results are explained in terms of the excessive generation of reactive oxygen species via photoexcitation of these photosensitizers in cancer cells. The fluorescence lifetimes of both photosensitizers in cancer cells are different from those in normal cells, which originates from the different intracellular environments around the photosensitizers between normal and cancer cells.

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Related in: MedlinePlus

Time dependence of fluorescence spectra of Na-Ph-a in WFB (left) and W31 (right) cells with irradiation of 405-nm light in air. The irradiation times were 0, 1, 2, 3, 4, 5, 10, 20, 30 and 40 min. The concentration of Na-Ph-a in the culture solution was 10 μM.
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sensors-15-11417-f008: Time dependence of fluorescence spectra of Na-Ph-a in WFB (left) and W31 (right) cells with irradiation of 405-nm light in air. The irradiation times were 0, 1, 2, 3, 4, 5, 10, 20, 30 and 40 min. The concentration of Na-Ph-a in the culture solution was 10 μM.

Mentions: Similar experiments have been done using Na-Ph-a as a photosentizer. Figure 8 shows time dependence of the fluorescence spectra of Na-Ph-a in WFB and W31 cells continuously irradiated at 405-nm light in air. The concentration of Na-Ph-a in the culture solution was 10 μM. The peak of the fluorescence was observed at around 670 nm and the difference in the peak wavelength between WFB and W31 cells was less than 2 nm. In both cells, the temporal decrease in the fluorescence intensity due to photobleaching was observed. The fluorescence intensity in W31 cells decreased more rapidly than that in W31 cells, as in the case of TPS. Plots of the fluorescence intensity of Na-Ph-a against the irradiation time, obtained from the spectra shown in Figure 8, are shown in Figure 9. It is clearly seen that the photobleaching of the fluorescence of Na-Ph-a efficiently occurs in W31 cells, whereas WFB cells exhibit only a slight change in the magnitude of the photobleaching. The photoinduced quenching of fluorescence of Na-Ph-a may come from the efficient generation of ROS, as mentioned above for TPS in cells. It should be mentioned that the fluorescence intensity of Na-Ph-a in PBS buffer was essentially the same during photoirradiation for 30 min.


Fluorescence characteristics and lifetime images of photosensitizers of talaporfin sodium and sodium pheophorbide a in normal and cancer cells.

Awasthi K, Yamamoto K, Furuya K, Nakabayashi T, Li L, Ohta N - Sensors (Basel) (2015)

Time dependence of fluorescence spectra of Na-Ph-a in WFB (left) and W31 (right) cells with irradiation of 405-nm light in air. The irradiation times were 0, 1, 2, 3, 4, 5, 10, 20, 30 and 40 min. The concentration of Na-Ph-a in the culture solution was 10 μM.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4481965&req=5

sensors-15-11417-f008: Time dependence of fluorescence spectra of Na-Ph-a in WFB (left) and W31 (right) cells with irradiation of 405-nm light in air. The irradiation times were 0, 1, 2, 3, 4, 5, 10, 20, 30 and 40 min. The concentration of Na-Ph-a in the culture solution was 10 μM.
Mentions: Similar experiments have been done using Na-Ph-a as a photosentizer. Figure 8 shows time dependence of the fluorescence spectra of Na-Ph-a in WFB and W31 cells continuously irradiated at 405-nm light in air. The concentration of Na-Ph-a in the culture solution was 10 μM. The peak of the fluorescence was observed at around 670 nm and the difference in the peak wavelength between WFB and W31 cells was less than 2 nm. In both cells, the temporal decrease in the fluorescence intensity due to photobleaching was observed. The fluorescence intensity in W31 cells decreased more rapidly than that in W31 cells, as in the case of TPS. Plots of the fluorescence intensity of Na-Ph-a against the irradiation time, obtained from the spectra shown in Figure 8, are shown in Figure 9. It is clearly seen that the photobleaching of the fluorescence of Na-Ph-a efficiently occurs in W31 cells, whereas WFB cells exhibit only a slight change in the magnitude of the photobleaching. The photoinduced quenching of fluorescence of Na-Ph-a may come from the efficient generation of ROS, as mentioned above for TPS in cells. It should be mentioned that the fluorescence intensity of Na-Ph-a in PBS buffer was essentially the same during photoirradiation for 30 min.

Bottom Line: The reduction of the fluorescence intensity by photoirradiation was observed for both photosensitizers in both cells, but the quenching rate was much faster in cancer cells than in normal cells.These results are explained in terms of the excessive generation of reactive oxygen species via photoexcitation of these photosensitizers in cancer cells.The fluorescence lifetimes of both photosensitizers in cancer cells are different from those in normal cells, which originates from the different intracellular environments around the photosensitizers between normal and cancer cells.

View Article: PubMed Central - PubMed

Affiliation: Research Institute for Electronic Science (RIES), Hokkaido University, Sapporo 001-0020, Japan. kaawasthi@gmail.com.

ABSTRACT
Fluorescence spectra and fluorescence lifetime images of talaporfin sodium and sodium-pheophorbide a, which can be regarded as photosensitizers for photodynamic therapy, were measured in normal and cancer cells. The reduction of the fluorescence intensity by photoirradiation was observed for both photosensitizers in both cells, but the quenching rate was much faster in cancer cells than in normal cells. These results are explained in terms of the excessive generation of reactive oxygen species via photoexcitation of these photosensitizers in cancer cells. The fluorescence lifetimes of both photosensitizers in cancer cells are different from those in normal cells, which originates from the different intracellular environments around the photosensitizers between normal and cancer cells.

Show MeSH
Related in: MedlinePlus