PuSH - Publication Server of Helmholtz Zentrum München

Wessels, J.M. ; Strauß, W.S.L. ; Seidlitz, H.K. ; Rück, A.C. ; Schneckenburger, H.

Intracellular localization of meso-tetraphenylporphine tetrasulphonate probed by time-resolved and microscopic fluorescence microscopoy.

J. Photochem. Photobiol. B-Biol. 12, 275-284 (1992)
DOI PMC
Open Access Green as soon as Postprint is submitted to ZB.
The effects of solvent pH on spectral properties and fluorescence decay kinetics were investigated in order to characterize the microenvironment of meso-tetraphenylporphine tetrasulphonate (TPPS4) taken up by cells. Steady-state absorption and fluorescence spectra of TPPS4 in buffer solutions of different pH were used to identify a ring protonated species at pH ≤ 4. This dication could also be distinguished from the unprotonated form by its altered fluorescence decay time (3.5 vs. 11.4 ns). In addition, tune-resolved spectroscopy gave some evidence of a monocationic species existing at pH 6-9. This was concluded from the occurrence of another component with a decay time of 5 ns. Measurements of the spectral and kinetic properties of the fluorescence emission of single epithelial cells (RR1022) uncubated with TPPS4 indicated that the sensitizer was mainly localized in a microenvironment with a pH of 5, a value which occurs intracellularly only within lysosomes. Cells kept in the dark exhibited the characteristic spectra of both the dication and the neutral form. The fluorescence decay showed two components with decay times of 2.6 ns ad 10.6 ns. Irradiation of the cells changed the decay times to 4.6 ns and 13.4 ns and the dication fluorescence emission peak vanished, which is in accordance with the results obtained from buffer solutions at pH ≥ 6. Therefore, we deduce that the photodynamic action leads to a rupture of the lysosomes and that the sensitizer is released into the surrounding cytoplasm.
Altmetric
Additional Metrics?
[➜Log in]
Edit extra informations Login
Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords Fluorescence Lifetimes ; Meso-tetraphenylporphine Tetrasulphonate ; Microspectrofluorometry ; Ph Dependence ; Photosensitization
ISSN (print) / ISBN 1011-1344
Journal Journal of Photochemistry and Photobiology B-Biology
Quellenangaben Volume: 12, Issue: 3, Pages: 275-284 Article Number: , Supplement: ,
Publisher Elsevier
Non-patent literature Publications
Reviewing status Peer reviewed
Institute(s) Institute of Groundwater Ecology (IGOE)