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12 January 1995 Tetrasulphonated aluminum phthalocyanine as a pH-sensitive probe
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Proceedings Volume 2325, Photodynamic Therapy of Cancer II; (1995)
Event: International Symposium on Biomedical Optics Europe '94, 1994, Lille, France
PH is a factor relevant for the molecular state of the sensitizer used in PDT and so may influence its photochemical activity and its interaction with cells and tissues. Thus the measurements of microenvironmental pH of the sensitizing molecule, its dynamics during irradiation with light and subsequent development of cell damage are interesting from the point of view of the PDT molecular and cellular mechanisms. Two ways of performing such measurements are suggested: the first one is to use conventional fluorescence or transmission pH-probes, and second using the sensitizer itself as such a probe. We show the complications arising in the first approach due to the interaction between the probing and sensitizing molecules on the example of measurements of the microenvironment pH of tetrasulphonated aluminum phthalocyanine (AlPcS4) in cultured cells with the use of neutral red. These complications are expected to be common also for the other conventional pH-probes. We studied concentrational and pH dependencies of the fluorescence emission, fluorescence excitation and absorbance spectra, and fluorescence lifetimes of AlPcS4 in aqueous solutions (10-6 M - 10-4 M) by means of stationary and laser picosecond fluorescence spectroscopies. With the use of numerical deconvolution of complex spectral curves (Alentsev - Fok algorithm) three individual components were found in AlPcS4 pH-dependent fluorescence spectra. Based on the spectral data we suggest a ratioing technique for the local pH measurements with the use of AlPcS4 as a fluorescence pH- sensitive probe. Microenvironmental pH of AlPcS4 molecules in cultured cells were estimated by means of the suggested technique.
© (1995) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Elena B. Chernyaeva, Marina Yu. Poroshina, L. V. Zhorina, A. V. Agronskaya, Andrey Yuri Chikishev, V. A. Schinov, S. Yu. Ardgantsev, and Maria G. Galpern "Tetrasulphonated aluminum phthalocyanine as a pH-sensitive probe", Proc. SPIE 2325, Photodynamic Therapy of Cancer II, (12 January 1995);

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