Direct Detection of Membrane Channels from Gels Using Water-in-Oil Droplet Bilayers

We form planar lipid bilayers between an aqueous droplet and a hydrogel support immersed in
a lipid−oil solution. By scanning the bilayer over the surface of an SDS−PAGE gel, we are able to directly
detect membrane proteins from gels using single-channel recording. Using this technique, we are able to
examine low levels of endogenous protein from cell extracts without the need for over-expression. We
also use droplet bilayers to detect small molecules from hydrogels. The bilayers show enhanced stability
compared to conventional planar lipid bilayers, and both bilayer size and position can be controlled during
an experiment. Hydrogel scanning with droplet bilayers provides a new method for the discovery and
characterization of ion channels with the potential for high-throughput screening.