Peer-Reviewed Journal Details
Mandatory Fields
Maher S.;Basit H.;Forster R.;Keyes T.
Micron dimensioned cavity array supported lipid bilayers for the electrochemical investigation of ionophore activity
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Optional Fields
Electrochemical impedance spectroscopy
© 2016 Elsevier B.V.Microcavity supported lipid bilayers, MSLBs, were applied to an electrochemical investigation of ionophore mediated ion transport. The arrays comprise of a 1 cm2 gold electrode imprinted with an ordered array of uniform spherical-cap pores of 2.8 μm diameter prepared by gold electrodeposition through polystyrene templating spheres. The pores were pre-filled with aqueous buffer prior to Langmuir-Blodgett assembly of a 1,2-dioleoyl-sn-glycero-3-phosphocholine bilayer. Fluorescence lifetime correlation spectroscopy enabled by the micron dimensions of the pores permitted study of lipid diffusion across single apertures, yielding a diffusion coefficient of 12.58 ± 1.28 μm2 s− 1 and anomalous exponent of 1.03 ± 0.02, consistent with Brownian motion. From FLCS, the MSLBs were stable over 3 days and electrochemical impedance spectroscopy of the membrane with and without ionic gradient over experimental windows of 6 h showed excellent stability. Two ionophores were studied at the MSLBs; Valinomycin, a K+ uniporter and Nigericin, a K+/H+ antiporter. Ionophore reconstituted into the DOPC bilayer resulted in a decrease and increase in membrane resistance and capacitance respectively. Significant increases in Valinomycin and Nigericin activity were observed, reflected in large decreases in membrane resistance when K+ was present in the contacting buffer and in the presence of H+ ionic gradient across the membrane respectively.
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