title: The effect of an oligonucleotide on the structure of cationic DODAB vesicles.
abstract: The effect of a small single-stranded oligonucleotide (ODN) on the structure of cationic DODAB vesicles was investigated by means of differential scanning calorimetry (DSC), small angle X-ray scattering (SAXS) and electron spin resonance (ESR) spectroscopy. ODN adsorption induced coalescence of vesicles and formation of multilamellar structures with close contact between lamellae. It also increased the phase transition temperature by 10 °C but decreased transition cooperativity. The ODN rigidified and stabilized the gel phase. In the fluid phase, a simultaneous decrease of ordering close to the bilayer surface and increase in bilayer core rigidity was observed in the presence of the ODN. These effects may be due not only to electrostatic shielding of DODAB head groups but also to superficial dehydration of the bilayers. The data suggest that oligonucleotides may induce the formation of a multilamellar poorly hydrated coagel-like phase below phase transition. These effects should be taken into account when planning ODN delivery employing cationic bilayer carriers.
authors.affiliation: Instituto de Física, Universidade de São Paulo, São Paulo, Brazil. julioroz@if.usp.br.
authors.forename: Julio H K
authors.initials: JH
authors.lastname: Rozenfeld
authors.forename: Evandro L
authors.initials: EL
authors.lastname: Duarte
authors.forename: Leandro R S
authors.initials: LR
authors.lastname: Barbosa
authors.forename: M Teresa
authors.initials: MT
authors.lastname: Lamy
mesh_terms: D008567:Membranes, Artificial; D009841:Oligonucleotides / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013816:Thermodynamics; D044366:Transition Temperature
chemical_list: D008567:Membranes, Artificial; D009841:Oligonucleotides; D000644:Quaternary Ammonium Compounds; C015831:dimethyldioctadecylammonium