Ligand Gated Ion Channels on the Qube

Abstract

Drug discovery on ion channel targets has been an under-explored territory because suitable screening tools for patch clamp were missing. This changed during the 2000's with the introduction of automated patch clamp (APC) devices. Still, the throughput and running cost of APC devices did not allow for the employment of the patch clamp assays in primary screening. Because of this bottleneck, APC has remained a secondary screening tool. We are now presenting data from the first true gigaseal-based 384-channel planar patch clamp system, the Qube, capable of providing the throughput needed for primary screening. The Qube is a collection of years of experience with planar patch clamp devices: High quality, reliability and easy to use concepts are the core in both the tried-and-tested silicon technology of the consumable, and in the technologies used in the instrument. The Qube offers GΩ seals and efficient integrated liquid flow in 384-well format.We show here that the Qube provides exceptional data quality for electrophysiological assays with fast desensitizing ligand-gated ion channels. The fast liquid exchange permits accurate XC50 estimations. We have tested the acid sensing ion channel (ASIC1) and the nicotinic acetylcholine receptor (nAchRα1) on the Qube in both agonist and antagonist configurations, showcasing the instrument's broad flexibility in terms of assay design.The results prove that: 1) Repetitive agonist applications result in reproducible current responses. 2) The agonist can be applied and washed off an unlimited number of times as long as the cell is stable. 3) XC50 values correspond to expected values (QPatch and literature).Collectively, our results show that the design of the flow channels on the Qube consumable enables recordings on ligand-gated ion channels with the highest throughput capacity seen so far, without compromising data quality, reproducibility or reliability.