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Hiraoka Wakako
Department Undergraduate School , School of Science and Technology Position Professor |
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| Language | English |
| Publication Date | 2008/02 |
| Type | Academic Journal |
| Peer Review | Peer reviewed |
| Title | Sonodynamic effect of photosensitizers : The enhancement of cell killing by a radical independent mechanism. |
| Contribution Type | Co-authored (first author) |
| Journal | Photomedicine and Photobiology |
| Volume, Issue, Page | 29,pp.4-7 |
| Author and coauthor | Wakako Hiraoka, Takakshi Kondo. |
| Details | To clarify the mechanism of the sonodynamic enhancement of cell killing with photosensitizers, we
have compared between sonodynamic effect and photodynamic effect with photosensitizers on free radical formation and cell killing. Ultrasound-induced enhancement of killing of human lymphoma U937 cells was shown in photosensitizer dyes; hematoporphyrine, rose bengal, erythrosine B, rhodamine 6G, rhodamine 123 and sulforhodamine B. ESR analysis using 2,2,6,6-tetramethyl-4-piperidone indicated the production of singlet oxygen from photo-irradiated dyes. On the other hand, sonochemical enhancement of generation of reactive oxygen species was not shown in sono-irradiated dyes. ESR-spin trapping using 3,5-dibromo-4-nitrosobenzene sulfonic acid showed carbon-centered radicals in sono-irradiated dyes. However, the dye radicals were not responsible for ultrasound-induced enhancement of cell killing by sensitizers. These results suggest that free radicals are not involved in the enhancement of ultrasound-induced cell killing and that the mechanism of enhancement should be mainly due to certain mechanical stress. |