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Wessels, J.M. ; Beisker, W. ; Seidlitz, H.K.

Kinetic and localization properties of protoporphyrin dimethyl ester in fibrosarcoma cells.

Proc. SPIE 2078, 363-370 (1994)
DOI
Open Access Green möglich sobald Postprint bei der ZB eingereicht worden ist.
Protoporphyrin-dimethylester (PP) is an amphiphilic porphyrin which shows a fast clearence and is therefore of interest for the photodynamic therapy. The localization of the sensitizer is one point of interest, since it has a strong influence on the photo toxic effect. Localization of PP in fibrosarcoma cells was probed by time resolved and steady state spectroscopy. Dioleoyl L- α-phosphatidylcholine (DOPC) liposomes were used as a carrier system for the amphiphilic sensitizer with a molar ratio of PP/DMSO = 1/200. Since intermembrane exchange is responsible for the uptake of PP we expected a membrane bound localization. Therefore the characterization of the microenvironment was based on the comparison of the spectroscopic properties of PP in organic solvents, artificial membranes and in cells. Cells were incubated with a concentration of 3.5·10-7 M in FCS free medium at T = 37°C for 4h. Aprotic solvents show a bathochromic shift of the Soret-band with increasing dielectric constant ∈ whereas the Q- bands exhibit no spectral shift within the instrumental resolution (Δλ=3nm). Additionally, the fluorescence decay time of the monomer (τ=(11.5±1.0)ns) remains constant. However, in aprotic solvents like dimethylsulfoxide, 1-propanol or ethylenglycol which exhibit an amphiphilic character we observed no spectral shift of the Soret-band with increasing € but an increase in the fluorescence decay time (τ=(16.8±1.2)ns). This decay time of PP is within the error margin in agreement with its monomer decay time in artificial membranes (τ=(16.8±1.0)ns) and in single cells (τ=(15.3±0.4)ns). Based on this comparison we suggest that PP is bound within the amphiphilic part of the membranes is between the polar headgroups and the fatty acyl chains of the cytoplasm membrane.
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Publikationstyp Artikel: Journalartikel
Dokumenttyp Wissenschaftlicher Artikel
Korrespondenzautor
ISSN (print) / ISBN 0277-786X
e-ISSN 1996-756X
Zeitschrift Proceedings of SPIE
Quellenangaben Band: 2078, Heft: , Seiten: 363-370 Artikelnummer: , Supplement: ,
Verlag SPIE
Nichtpatentliteratur Publikationen
Begutachtungsstatus Peer reviewed
Institut(e) Abteilung Biophysikalische Strahlenforschung