title: Ion channel pharmacology under flow: automation via well-plate microfluidics.
abstract: Automated patch clamping addresses the need for high-throughput screening of chemical entities that alter ion channel function. As a result, there is considerable utility in the pharmaceutical screening arena for novel platforms that can produce relevant data both rapidly and consistently. Here we present results that were obtained with an innovative microfluidic automated patch clamp system utilizing a well-plate that eliminates the necessity of internal robotic liquid handling. Continuous recording from cell ensembles, rapid solution switching, and a bench-top footprint enable a number of assay formats previously inaccessible to automated systems. An electro-pneumatic interface was employed to drive the laminar flow of solutions in a microfluidic network that delivered cells in suspension to ensemble recording sites. Whole-cell voltage clamp was applied to linear arrays of 20 cells in parallel utilizing a 64-channel voltage clamp amplifier. A number of unique assays requiring sequential compound applications separated by a second or less, such as rapid determination of the agonist EC(50) for a ligand-gated ion channel or the kinetics of desensitization recovery, are enabled by the system. In addition, the system was validated via electrophysiological characterizations of both voltage-gated and ligand-gated ion channel targets: hK(V)2.1 and human Ether-à-go-go-related gene potassium channels, hNa(V)1.7 and 1.8 sodium channels, and (α1) hGABA(A) and (α1) human nicotinic acetylcholine receptor receptors. Our results show that the voltage dependence, kinetics, and interactions of these channels with pharmacological agents were matched to reference data. The results from these IonFlux™ experiments demonstrate that the system provides high-throughput automated electrophysiology with enhanced reliability and consistency, in a user-friendly format.
authors.affiliation: Fluxion Biosciences, Inc., South San Francisco, California 94080, USA.
authors.forename: C Ian
authors.initials: CI
authors.lastname: Spencer
authors.forename: Nianzhen
authors.initials: N
authors.lastname: Li
authors.forename: Qin
authors.initials: Q
authors.lastname: Chen
authors.forename: Juliette
authors.initials: J
authors.lastname: Johnson
authors.forename: Tanner
authors.initials: T
authors.lastname: Nevill
authors.forename: Juha
authors.initials: J
authors.lastname: Kammonen
authors.forename: Cristian
authors.initials: C
authors.lastname: Ionescu-Zanetti
mesh_terms: D000818:Animals; D001331:Automation / Q000379:methods*; D016466:CHO Cells; D018118:Chloride Channels / Q000187:drug effects; D006224:Cricetinae; D003412:Cricetulus; D051638:Ether-A-Go-Go Potassium Channels / Q000187:drug effects; D057809:HEK293 Cells; D057166:High-Throughput Screening Assays / Q000379:methods*; D006801:Humans; D007473:Ion Channels / Q000187:drug effects*; D051663:Kv1.2 Potassium Channel / Q000187:drug effects; D046210:Microfluidic Analytical Techniques; D062556:NAV1.7 Voltage-Gated Sodium Channel / Q000187:drug effects; D062559:NAV1.8 Voltage-Gated Sodium Channel / Q000187:drug effects; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology; D011950:Receptors, Cholinergic / Q000187:drug effects; D011963:Receptors, GABA-A / Q000187:drug effects; D015203:Reproducibility of Results; D026941:Sodium Channel Blockers / Q000494:pharmacology; D012996:Solutions
chemical_list: D018118:Chloride Channels; D051638:Ether-A-Go-Go Potassium Channels; D007473:Ion Channels; C496884:KCNH1 protein, human; D051663:Kv1.2 Potassium Channel; D062556:NAV1.7 Voltage-Gated Sodium Channel; D062559:NAV1.8 Voltage-Gated Sodium Channel; D026902:Potassium Channel Blockers; D011950:Receptors, Cholinergic; D011963:Receptors, GABA-A; C568317:SCN10A protein, human; C486866:SCN9A protein, human; D026941:Sodium Channel Blockers; D012996:Solutions