A metal-supported biomimetic micromembrane allowing the recording of single-channel activity and of impedance spectra of membrane proteins

A novel tethered bilayer lipid micromembrane (tBL mu M) was prepared and characterized. It consists of a mercury cap electrodeposited on a platinum microelectrode, about 20 pm in diameter. The micromembrane was prepared by tethering to the mercury cap a thiolipid monolayer and by then self-assembling a lipid monolayer on top of it. The thiolipid consisted of a disulfidated tetraoxyethylene hydrophilic spacer covalently linked to two phytanyl chains. Upon incorporating OmpF porin in the tBL mu M, its single-channel activity was recorded by the patch-clamp technique, and its particular features described. An electrochemical impedance spectrum of the tBL mu M incorporating OmpF porin is also reported. To the best of our knowledge, this tBL mu M is the first metal-supported biomimetic micromembrane capable of incorporating non-engineered channel proteins in a functionally active state from their detergent solutions, and of allowing the recording of single-channel activity and of impedance spectra of these proteins via ion translocation into the hydrophilic spacer. The limited spaciousness of the spacer prevents a statistical analysis based on current-amplitude or blockage-time histograms. Nonetheless, the robustness, stability, ease of preparation and disposability of the present tBL mu M may open the way to the realization of a channel-protein microarray platform allowing a high throughput drug screening. (C) 2009 Elsevier B.V. All rights reserved.