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See detailDetermination of the singlet oxygen quantum yield of bacteriochlorin a: a comparative study in phosphate buffer and aqueous dispersion of dimiristoyl-L-a-phosphatidylcholine liposomes
Hoebeke, Maryse ULg; Damoiseau, Xavier

in Photochemical & Photobiological Sciences (2002), 1(4), 283-287

The production of singlet oxygen (1O2) by bacteriochlorin a (BCA) was studied in phosphate buffer and in dimyristoyl-L-α-phosphatidylcholine (DMPC) unilamellar liposomes. The comparative method used to ... [more ▼]

The production of singlet oxygen (1O2) by bacteriochlorin a (BCA) was studied in phosphate buffer and in dimyristoyl-L-α-phosphatidylcholine (DMPC) unilamellar liposomes. The comparative method used to measure 1O2 production was a quantitative analysis of photooxidation reactions leading to the loss of absorbance of the water-soluble specific probe: anthracene 9,10-dipropionic acid. Rose Bengal, whose 1O2 quantum yield (ΦRB) is well known in alcohols and phosphate buffer, was used as the standard for the quantification of the BCA singlet oxygen production. Our results confirm quantitatively that solubilization of BCA in liposomes leads to an increase in 1O2 production. Indeed, the quantum yield of 1O2 production by BCA (ΦBCA) is 0.05 in phosphate buffer and 0.33 in DMPC liposomes. Furthermore, the diffusion characteristics of 1O2 produced by BCA bound to liposome were also examined using the isotopic lifetime enhancement effect of D2O. It was shown that 1O2 spent at least 70% of its lifetime in the vesicular environment [less ▲]

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See detailNew method for nitroxyl radical synthesis
Claes, M.; Detrembleur, Christophe ULg; Hoebeke, Maryse ULg et al

Conference (2002)

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See detailDMPO for quantitative measurements of singlet oxygen production?
Damoiseau, X.; Heyne, B.; Hoebeke, Maryse ULg

Conference (2002)

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See detailL'imagerie de RMN
Hoebeke, Maryse ULg

Scientific conference (2001, October)

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See detailIncrease of the Photosensitizing Efficiency of the Bacteriochlorin a by Liposome-Incorporation
Damoiseau, X.; Schuitmaker, H. J.; Lagerberg, J. W. et al

in Journal of Photochemistry and Photobiology B : Biology (2001), 60(1), 50-60

To describe the action mechanisms of Bacteriochlorin a (BCA), a second generation photosensitizer, in phosphate buffer (PB) and in dimyristoyl phosphatidylcholine (DMPC) liposomes we carried out oxygen ... [more ▼]

To describe the action mechanisms of Bacteriochlorin a (BCA), a second generation photosensitizer, in phosphate buffer (PB) and in dimyristoyl phosphatidylcholine (DMPC) liposomes we carried out oxygen consumption and ESR measurements. In PB, where BCA was in a monomer-dimer equilibrium, our results suggested that the oxygen consumption was related to the BCA monomers concentration in solution. Incorporation of BCA in DMPC liposomes, by promoting the monomerization of BCA, increased 9-fold the oxygen consumption in comparison to the value in PB. The use of specific singlet oxygen quenchers (Azide and 9,10-Anthracenedipropionic acid) in ESR and oxygen consumption experiments allowed us to assert that BCA was mainly a type II sensitizer when it was incorporated in DMPC. Finally, the cell survival of WiDr cells after a PDT treatment was measured for cells incubated with BCA in cell culture medium and cells incubated with BCA in DMPC. Irrespective of the dye concentration, the cell survival was lower when liposomes were used. This effect could be the result of a better BCA monomerization and/or a different BCA uptake in cells. [less ▲]

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See detailESR associated with spin-labelling methods into the study of photosensitization in liposomal solutions
Hoebeke, Maryse ULg

in Bulletin de la Société Royale des Sciences de Liège (2000)

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See detailApplications biomédicales de la RPE
Hoebeke, Maryse ULg

Scientific conference (1999, December)

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See detailFluorescence, Absorption and Electron Spin Resonance Study of Bacteriochlorin a Incorporation into Membrane Models
Hoebeke, Maryse ULg; Damoiseau, X.; Schuitmaker, H. J. et al

in Biochimica et Biophysica Acta (1999), 1420(1-2), 73-85

Analysis of the bacteriochlorin a absorption spectra suggests the existence of a monomer-dimer equilibrium, particularly intense in phosphate buffer and favored by a decrease of the pH. The dye in ... [more ▼]

Analysis of the bacteriochlorin a absorption spectra suggests the existence of a monomer-dimer equilibrium, particularly intense in phosphate buffer and favored by a decrease of the pH. The dye in methanolic solution is predominantly in monomeric form. Fluorescence and electron spin resonance nitroxide spin labeling measurements indicate that incorporation into the lipid phase of dimyristoyl-L-alpha-phosphatidylcholine liposomes induces dye monomerization. Moreover, the molecules are bound in the external surface of the vesicles and a complete incorporation is ensured by a lipid-to-dye ratio greater than 125. [less ▲]

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See detailA spectroscopic study inside liposomes of propofol singlet oxygen quenching properties
Heyne, B.; Mouithys-Mickalad, Ange ULg; Hans, P. et al

Conference (1999)

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See detailIncrease of the bacteriochlorin a photosensitizing efficiency by incorporation in liposomes
Damoiseau, X.; Schuitmaker, H.; Hoebeke, Maryse ULg

Conference (1999)

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See detailESR study of Bacteriochlorin a incorporation into membranes models
Hoebeke, Maryse ULg

Scientific conference (1999)

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See detailElectron spin resonance study of basteriochlorin a incorporation into membranes models
Hoebeke, Maryse ULg; Damoiseau, X.; Schuitmaker, H. et al

Conference (1999)

Detailed reference viewed: 3 (1 ULg)