Two-Photon Excitation of 4'-Hydroxymethyl-4,5',8-Trimethylpsoralen
| Autor: | Steven G. Boxer, Warren K. Hoeffler, Dennis H. Oh, Michael W. Berns, Robert J. Stanley, Eugene A. Bauer, Michelle Lin |
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| Rok vydání: | 1997 |
| Předmět: |
Rhodamines
Chemistry Lasers Spectrophotometry Atomic Absorption cross section Quantum yield General Medicine Laser Photochemistry Biochemistry law.invention Two-photon excitation microscopy law Aluminum Oxide Sapphire Trioxsalen Irradiation Emission spectrum Physical and Theoretical Chemistry Excitation |
| Zdroj: | Photochemistry and Photobiology. 65:91-95 |
| ISSN: | 1751-1097 0031-8655 |
| Popis: | Psoralens are a class of pharmaceutical agents commonly used to treat several cutaneous disorders. When irradiated with a mode-locked titanium: sapphire (Ti:sapphire) laser tuned to 730 nm, an aqueous solution of 4'-hydroxymethyl-4,5',8-trimethylpsoralen (HMT) emits blue light. The emission spectrum is centered at 452 nm and is identical to that obtained by one-photon excitation with UVA excitation, and its magnitude depends quadratically on the intensity of laser excitation. These results suggest that two-photon excitation occurs to a potentially photochemically active state. To estimate the two-photon absorption cross section, it was first necessary to measure the emission quantum yield of HMT using 365 nm excitation at room temperature that resulted in a value of 0.045 +/- 0.007. The two-photon absorption cross section of HMT at 730 nm is therefore estimated to be 20 x 10(-50) cm4 s (20 Göppert-Mayer). The excited-state photophysics and photochemistry of psoralens suggest potential applications to cutaneous phototherapy in diseases such as psoriasis and dystrophic epidermolysis bullosa. |
| Databáze: | OpenAIRE |
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