Spectroscopic studies of photosensitization in solutions and in cells

Benjamin Ehrenberg; Leonid Roitman; Adina Lavi; Yeshayahu Nitzan; Zvi Malik; Jonathan L. Sessler

doi:10.1117/12.199180

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12 January 1995 Spectroscopic studies of photosensitization in solutions and in cells

Benjamin Ehrenberg; Leonid Roitman; Adina Lavi; Yeshayahu Nitzan; Zvi Malik; Jonathan L. Sessler

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Proceedings Volume 2325, Photodynamic Therapy of Cancer II; (1995) https://doi.org/10.1117/12.199180
Event: International Symposium on Biomedical Optics Europe '94, 1994, Lille, France

Abstract

We employ classical porphyrins, as well as second-generation sensitizers, such as tetrabenzo- porphyrins, naphthaloporphyrins, texaphyrins, and sapphyrins for biological photosensitization. We studied the extent of sensitizer binding to biological membranes and bacterial cells; the singlet oxygen production yield in homogeneous solutions and in membranes; and the efficiency of the photo-cytotoxic effect of the sensitizers. In carrying out these studies, absorption and fluorescence spectra were used as monitoring techniques. We demonstrate a spectroscopic probing procedure, based on the well established chemical quencher of singlet oxygen, DPIBF, which at appropriate concentration allows a simple mathematical evaluation of the absolute quantum yield of singlet oxygen production. The method does not rely on any predetermined kinetic values and provides a result with high accuracy. The relative efficiency of competing photochemical processes in cells was established, so that the likely mechanism which is responsible for the death of the cell could be pointed out. A unique and exceptional wavelength dependence of photophysical properties is described.

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Benjamin Ehrenberg, Leonid Roitman, Adina Lavi, Yeshayahu Nitzan, Zvi Malik, and Jonathan L. Sessler "Spectroscopic studies of photosensitization in solutions and in cells", Proc. SPIE 2325, Photodynamic Therapy of Cancer II, (12 January 1995); https://doi.org/10.1117/12.199180

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