Fluorescence, absorption and electron spin resonance study of bacteriochlorin a incorporation into membrane models.
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.
Hoebeke
M
M
Department of Experimental Physics, Institute of Physics B5, University of Liège, 4000, Liège, Belgium.
Damoiseau
X
X
Schuitmaker
H J
HJ
Van de Vorst
A
A
D019281:Dimerization; D004134:Dimyristoylphosphatidylcholine; D004578:Electron Spin Resonance Spectroscopy; D006863:Hydrogen-Ion Concentration; D008081:Liposomes; D046911:Macromolecular Substances; D008567:Membranes, Artificial; D008968:Molecular Conformation; D017319:Photosensitizing Agents / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*; D012996:Solutions; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry
D008081:Liposomes; D046911:Macromolecular Substances; D008567:Membranes, Artificial; D017319:Photosensitizing Agents; D011166:Porphyrins; D012996:Solutions; C065423:bacteriochlorin a; D004134:Dimyristoylphosphatidylcholine