title: Polymorphism of pyridinium amphiphiles for gene delivery: influence of ionic strength, helper lipid content, and plasmid DNA complexation.
abstract: Two double-tailed pyridinium cationic amphiphiles, differing only in the degree of unsaturation of the alkyl chains, have been selected for a detailed study of their aggregation behavior, under conditions employed for transfection experiments. The transfection efficiencies of the two molecules are remarkably different, especially when combined with 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE) as helper lipid. The phase behavior of the cationic amphiphile/DOPE mixtures have been studied using (31)P- and (2)H-NMR (on deuterated cationic amphiphiles) as main techniques, to monitor independently the behavior of the two components. In water, the lamellar organization is dominant for both the surfactants in their mixtures with the helper lipid. In HEPES saline buffer (HBS), the mixtures of the unsaturated surfactant form inverted phases and, in particular, stable H(II) phases for DOPE contents > or =30 mol %. By contrast, the saturated surfactant does not form homogeneously mixed inverted phases in mixtures with DOPE at room temperature. However, mixed inverted phases are observed for this system at higher temperatures and, after mixing has been achieved by heating, the metastable mixed phases remain present for several hours at 5 degrees C. At 35 degrees C the dominant phase is the cubic phase. The lipoplex composed of equimolar mixtures of the unsaturated surfactant with DOPE and plasmid DNA was found to be organized in highly curved bilayers.
authors.affiliation: Physical Organic Chemistry Unit, Stratingh Institute, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
authors.forename: Marco
authors.initials: M
authors.lastname: Scarzello
authors.forename: Vladimir
authors.initials: V
authors.lastname: Chupin
authors.forename: Anno
authors.initials: A
authors.lastname: Wagenaar
authors.forename: Marc C A
authors.initials: MC
authors.lastname: Stuart
authors.forename: Jan B F N
authors.initials: JB
authors.lastname: Engberts
authors.forename: Ron
authors.initials: R
authors.lastname: Hulst
mesh_terms: D004337:Drug Carriers / Q000032:analysis / Q000737:chemistry*; D016503:Drug Delivery Systems / Q000379:methods; D018390:Gene Targeting / Q000379:methods*; D007477:Ions; D008051:Lipid Bilayers / Q000737:chemistry*; D008081:Liposomes / Q000032:analysis / Q000737:chemistry*; D010714:Phosphatidylethanolamines / Q000032:analysis / Q000737:chemistry*; D010957:Plasmids / Q000008:administration & dosage / Q000032:analysis / Q000737:chemistry*; D011726:Pyridinium Compounds / Q000032:analysis / Q000737:chemistry*; D014162:Transfection / Q000379:methods*
chemical_list: C410262:1,2-dioleoyl-glycero-3-phosphatidyl ethanolamine; D004337:Drug Carriers; D007477:Ions; D008051:Lipid Bilayers; D008081:Liposomes; D010714:Phosphatidylethanolamines; D011726:Pyridinium Compounds