title: Interaction of cationic lipid vesicles with model cell membranes--as determined by neutron reflectivity.
abstract: Transfection of cells by DNA (for the purposes of gene therapy) can be effectively engineered through the use of cationic lipid/DNA "lipoplexes", although the transfection efficiency of these lipoplexes is sensitive to the neutral "helper" lipid included. Here, neutron reflectivity has been used to investigate the role of the helper lipid present during the interaction of cationic lipid vesicles with model cell membranes. Dimethyldioctadecylammonium bromide (DDAB) vesicles were formed with two different helper lipids, 1,2-dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE) and cholesterol, and the interaction of these vesicles with a supported phospholipid bilayer was determined. DOPE-containing vesicles were found to interact faster with the membrane than those containing cholesterol, and vesicles containing either of the neutral helper lipids were found to interact faster than when DDAB alone was present. The interaction between the vesicles and the membrane was characterized by an exchange of lipid between the membrane and the lipid aggregates in solution; the deposition of vesicle bilayers on the surface of the membrane was not apparent.
authors.affiliation: Institut Laue-Langevin, 6 rue Jules Horowitz, BP 156, 38042 Grenoble Cedex 9, France.
authors.forename: P
authors.initials: P
authors.lastname: Callow
authors.forename: G
authors.initials: G
authors.lastname: Fragneto
authors.forename: R
authors.initials: R
authors.lastname: Cubitt
authors.forename: D J
authors.initials: DJ
authors.lastname: Barlow
authors.forename: M J
authors.initials: MJ
authors.lastname: Lawrence
authors.forename: P
authors.initials: P
authors.lastname: Timmins
mesh_terms: D002412:Cations / Q000737:chemistry; D002462:Cell Membrane / Q000737:chemistry*; D002784:Cholesterol / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry; D009502:Neutrons; D010714:Phosphatidylethanolamines / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012542:Scattering, Radiation; D012825:Silicon / Q000737:chemistry; D013499:Surface Properties
chemical_list: C410262:1,2-dioleoyl-glycero-3-phosphatidyl ethanolamine; D002412:Cations; D008051:Lipid Bilayers; D010714:Phosphatidylethanolamines; D000644:Quaternary Ammonium Compounds; C015831:dimethyldioctadecylammonium; D002784:Cholesterol; D012825:Silicon