Screening ion-channel ligand interactions with passive pumping in a microfluidic bilayer lipid membrane chip |
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| Authors: | Shimul C Saha Andrew M Powl B A Wallace Maurits R R de Planque Hywel Morgan |
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| Institution: | 1Electronics and Computer Science and Institute for Life Sciences, University of Southampton, Southampton SO17 1BJ, United Kingdom;2Institute of Structural and Molecular Biology, Birkbeck College, University of London, London WC1E 7HX, United Kingdom |
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| Abstract: | We describe a scalable artificial bilayer lipid membrane platform for rapid electrophysiological screening of ion channels and transporters. A passive pumping method is used to flow microliter volumes of ligand solution across a suspended bilayer within a microfluidic chip. Bilayers are stable at flow rates up to ∼0.5 μl/min. Phospholipid bilayers are formed across a photolithographically defined aperture made in a dry film resist within the microfluidic chip. Bilayers are stable for many days and the low shunt capacitance of the thin film support gives low-noise high-quality single ion channel recording. Dose-dependent transient blocking of α-hemolysin with β-cyclodextrin (β-CD) and polyethylene glycol is demonstrated and dose-dependent blocking studies of the KcsA potassium channel with tetraethylammonium show the potential for determining IC50 values. The assays are fast (30 min for a complete IC50 curve) and simple and require very small amounts of compounds (100 μg in 15 μl). The technology can be scaled so that multiple bilayers can be addressed, providing a screening platform for ion channels, transporters, and nanopores. |
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