title: Impedance analysis of ion transport through gramicidin channels in supported lipid bilayers.
abstract: Selectivity between monovalent cations and its sequence of conductivity in lipid bilayers doped with the antibiotic Gramicidin D (GD) were examined using EIS. Experiments were performed using lipid bilayers obtained from a lipid mixture of phosphatidylcholine and dimethyldioctadecylammonium chloride (DODAC). Lipid bilayers were supported on gold surfaces modified with a mercapto-carboxylic acid. The bilayers were formed by chemisorption of this last species to form the first monolayer on gold and subsequent fusion of unilamellar vesicles to form an external bilayer attached by electrostatic interactions. A mathematical expression for the impedance of the membrane processes was derived. Some predictions of the presented model were checked after fitting the experimental results in various electrolyte compositions.
authors.affiliation: Laboratorio de Ingeniería de Corrosión y Tecnología Electroquímica (LICTE), Facultad de Ingeniería, Universidad Nacional de La Plata, 1 y 47, 1900 La Plata, Argentina.
authors.forename: A E
authors.initials: AE
authors.lastname: Vallejo
authors.forename: C A
authors.initials: CA
authors.lastname: Gervasi
mesh_terms: D017097:Electric Impedance; D004563:Electrochemistry / Q000295:instrumentation / Q000379:methods; D006046:Gold; D006096:Gramicidin / Q000737:chemistry*; D017136:Ion Transport; D008051:Lipid Bilayers / Q000737:chemistry*; D008561:Membrane Fusion; D008954:Models, Biological; D010713:Phosphatidylcholines / Q000737:chemistry; D000644:Quaternary Ammonium Compounds / Q000737:chemistry
chemical_list: D008051:Lipid Bilayers; D010713:Phosphatidylcholines; D000644:Quaternary Ammonium Compounds; D006096:Gramicidin; C015831:dimethyldioctadecylammonium; D006046:Gold