X. Damoiseau et al., Increase of the photosensitizing efficiency of the Bacteriochlorin a by liposome-incorporation, J PHOTOCH B, 60(1), 2001, pp. 50-60
Citations number
37
Categorie Soggetti
Biochemistry & Biophysics
Journal title
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY
To describe the action mechanisms of Bacteriochlorin a (BCA), a second gene
ration photosensitizer, in phosphate buffer (PB) and in dimyristoyl phospha
tidylcholine (DMPC) liposomes we carried out oxygen consumption and ESR mea
surements. In PB, where BCA was in a monomer-dimer equilibrium, our results
suggested that the oxygen consumption was related to the BCA monomers conc
entration in solution. Incorporation of BCA in DMPC liposomes, by promoting
the monomerization of BCA, increased 9-fold the oxygen consumption in comp
arison to the value in PB. The use of specific singlet oxygen quenchers (Az
ide and 9, 10-Anthracenedipropionic acid) in ESR and oxygen consumption exp
eriments 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 afte
r 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 conce
ntration, 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. (C) 2001 Elsevier Science B.V. All rights reserved.