Lipid bilayer arrays: Cyclically formed and measured

Abstract

Artificial lipid bilayers have many uses. They are well established for scientific studies of reconstituted ion channels, used to host engineered pore proteins for sensing, and can potentially be applied in DNA sequencing. Droplet bilayers have significant technological potential for enabling many of these applications due to their compatibility with automation and array platforms. To further develop this potential, we have simplified the formation and electrical measurement of droplet bilayers using an apparatus that only requires fluid dispensation. We achieved simultaneous bilayer formation and measurement over a 32-element array with ~80% yield and no operator input following fluid addition. Cycling these arrays resulted in the formation and measurement of 96 out of 120 possible bilayers in 80 minutes, a sustainable rate that could significantly increase with automation and greater parallelization. This turn-key, high-yield approach to making artificial lipid bilayers requires no training, making the capability of creating and measuring lipid bilayers and ion channels accessible to a much wider audience. In addition, this approach is low-cost, parallelizable, and automatable, allowing high-throughput studies of ion channels and pore proteins in lipid bilayers for sensing or screening applications.

Single channel and ensemble hERG conductance measured in droplet bilayers

“…The ability to use mammalian cells also lifts any restrictions on ion channel expression in yeast or bacteria. We are continuing to work with this system to extend these results to additional measurement conditions and drugs, to determine the system's compatibility with measurement of other ion channels, and to parallelize the measurement (Lu et al 2014). The demonstrated compatibility of droplet bilayers with automated measurement (Poulos et al 2010) raises the possibility of its use for the performance of ion channel drug screening assays.…”

Measurement of Ensemble TRPV1 Ion Channel Currents Using Droplet Bilayers

“…Droplet bilayers have been explored for sensing and screening applications with microfluidic devices, arrays, and automation hardware. [ 6 , 12 – 15 , 21 , 22 ] Since measurement of ion channel ensemble currents have been reported for a number of ion channels in droplet bilayers,[ 8 – 11 ] these technological capabilities may enable electrophysiological screening of pharmaceuticals. DPhPC is a commonly used artificial lipid in droplet bilayer applications, as it is much less labile than unsaturated lipids.…”

“…We have used the droplet bilayer technique to study TRPM8 and hERG ion channels, showing modulation of ion channel conductance as a function of voltage, time, temperature, and presence of various drugs as a function of concentration. [ 9 – 11 ] The droplet bilayer technique is also particularly amenable to parallelization and automation;[ 12 – 15 ] this, combined with numerous commercially available engineered ion channel-expressing cell lines, gives this technology considerable potential for drug discovery and screening assays.…”

A droplet microfluidic system for sequential generation of lipid bilayers and transmembrane electrical recordings

“…We hope that the technique reported here is a step towards the construction of systems for high-throughput in vitro tests of the activity of membrane proteins, in which sequential screens might be combined with parallelization. 19,58,59…”