Potassium ion transport by gramicidin and valinomycin across a Ag(111)-supported tethered bilayer lipid membrane

Becucci, L., Innocenti, M., Salvietti, E., Rindi, A., Pasquini, I., Vassalli, M. , Foresti, M. L. and Guidelli, R. (2008) Potassium ion transport by gramicidin and valinomycin across a Ag(111)-supported tethered bilayer lipid membrane. Electrochimica Acta, 53(22), pp. 6372-6379. (doi: 10.1016/j.electacta.2008.04.043)

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Abstract

A tethered bilayer lipid membrane (tBLM) was prepared by anchoring a thiolipid monolayer to a Ag(1 1 1) single crystal from a thiolipid solution in ethanol; a diphytanoylphosphatidylcholine monolayer was then self-assembled on top of the thiolipid monolayer from a lipid solution in hexane or ethanol. The thickness of the mixed thiolipid|lipid bilayer was estimated at 7.5 ± 0.5 nm by scratching holes in the tBLM with an AFM tip and determining their height profile and the frequency distribution of height. The effect of the incorporation of gramicidin A and valinomycin upon K+ ion transport across the tBLM was investigated by electrochemical impedance spectroscopy. The position of the inflection point of the sigmoidal curve of the in-phase component of the electrode admittance against potential allowed the determination of an approximate scale of the absolute potential difference across the whole Ag(1 1 1)|(aqueous solution) interface, on the basis of a model of the electrified interface.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Vassalli, Professor Massimo
Authors: Becucci, L., Innocenti, M., Salvietti, E., Rindi, A., Pasquini, I., Vassalli, M., Foresti, M. L., and Guidelli, R.
College/School:College of Science and Engineering > School of Engineering > Biomedical Engineering
Journal Name:Electrochimica Acta
Publisher:Elsevier
ISSN:0013-4686
ISSN (Online):1873-3859

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