Screening ion-channel ligand interactions with passive pumping in a microfluidic bilayer lipid membrane chip

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 similar to 0.5 mu l/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 lownoise high-quality single ion channel recording. Dose-dependent transient blocking of alpha-hemolysin with beta-cyclodextrin (beta-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 mu g in 15 mu l). The technology can be scaled so that multiple bilayers can be addressed, providing a screening platform for ion channels, transporters, and nanopores. (c) 2015 AIP Publishing LLC.