title: Quantification of Randomly-methylated-beta-cyclodextrin effect on liposome: an ESR study.
abstract: In the present work, the effect of Randomly-methylated-beta-cyclodextrin (Rameb) on the microviscosity of dimyristoyl-l-alpha phosphatidylcholine (DMPC) bilayer was investigated using the electron spin resonance (ESR) technique. The ability of Rameb to extract membrane cholesterol was demonstrated. For the first time, the percentage of cholesterol extracted by Rameb from cholesterol doped DMPC bilayer was monitored and quantified throughout a wide Rameb concentration range. The effect of cholesterol on the inner part of the membrane was also investigated using 16-doxyl stearic acid spin label (16-DSA). 16-DSA seems to explore two different membrane domains and report their respective microviscosities. ESR experiments also establish that the presence of 30% of cholesterol in DMPC liposomes suppresses the jump in membrane fluidity at lipids phase-transition temperature (23.9 degrees C).
authors.affiliation: Department of Physics, Laboratory of Biomedical Spectroscopy, Institute of Physics, B5, University of Liège, Sart-Tilman, B-4000 Liège, Belgium. A.Grammenos@ulg.ac.be
authors.forename: A
authors.initials: A
authors.lastname: Grammenos
authors.forename: M A
authors.initials: MA
authors.lastname: Bahri
authors.forename: P H
authors.initials: PH
authors.lastname: Guelluy
authors.forename: G
authors.initials: G
authors.lastname: Piel
authors.forename: M
authors.initials: M
authors.lastname: Hoebeke
mesh_terms: D002784:Cholesterol / Q000737:chemistry*; D003497:Cyclic N-Oxides / Q000737:chemistry; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D008051:Lipid Bilayers / Q000737:chemistry; D008081:Liposomes / Q000737:chemistry*; D008745:Methylation; D013113:Spin Labels; D014783:Viscosity; D047392:beta-Cyclodextrins / Q000737:chemistry*
chemical_list: D003497:Cyclic N-Oxides; D008051:Lipid Bilayers; D008081:Liposomes; D013113:Spin Labels; D047392:beta-Cyclodextrins; C032363:16-nitroxystearic acid; D002784:Cholesterol; C031215:betadex; D004134:Dimyristoylphosphatidylcholine