title: Characterization of potassium channel modulators with QPatch automated patch-clamp technology: system characteristics and performance.
abstract: Planar silicon chips with 1-2-microm etched holes (average resistance: 2.04 +/- 0.02 MOmega in physiological buffer, n = 274) have been developed for patch-clamp recordings of whole-cell currents from cells in suspension. An automated 16-channel parallel screening system, QPatch 16, has been developed using this technology. A single-channel prototype of the QPatch system was used for validation of the patch-clamp chip technology. We present here data on the quality of patch-clamp recordings and from actual drug screening studies of human potassium channels expressed in cultured cell lines. Using Chinese hamster ovary (CHO) and human embryonic kidney cells (HEK), gigaseals of 4.1 +/- 0.4 GOmega (n = 146) and high-quality whole-cell current recordings were obtained from hERG and KCNQ4 potassium channels. Success rates for gigaseal recordings varied from 40 to 95%, and 67% of the whole-cell configurations lasted for >20 min. Cells were maintained in suspension up to 4 h in a cell storage facility that is integrated in the QPatch 16. No decline in patchability was observed during this time course. A series of screens was conducted with known inhibitors of the hERG and KCNQ4 potassium channels. Dose-response relationship characterizations of verapamil and rBeKm-1 blockage of hERG currents provided IC(50) values similar to values reported in the literature.
authors.affiliation: Sophion Bioscience A/S, Ballerup, Denmark.
authors.forename: Jonatan
authors.initials: J
authors.lastname: Kutchinsky
authors.forename: Søren
authors.initials: S
authors.lastname: Friis
authors.forename: Margit
authors.initials: M
authors.lastname: Asmild
authors.forename: Rafael
authors.initials: R
authors.lastname: Taboryski
authors.forename: Simon
authors.initials: S
authors.lastname: Pedersen
authors.forename: Ras K
authors.initials: RK
authors.lastname: Vestergaard
authors.forename: Rasmus B
authors.initials: RB
authors.lastname: Jacobsen
authors.forename: Karen
authors.initials: K
authors.lastname: Krzywkowski
authors.forename: Rikke L
authors.initials: RL
authors.lastname: Schrøder
authors.forename: Trine
authors.initials: T
authors.lastname: Ljungstrøm
authors.forename: Nathalie
authors.initials: N
authors.lastname: Hélix
authors.forename: Claus B
authors.initials: CB
authors.lastname: Sørensen
authors.forename: Morten
authors.initials: M
authors.lastname: Bech
authors.forename: Niels J
authors.initials: NJ
authors.lastname: Willumsen
mesh_terms: D000818:Animals; D001709:Biotechnology / Q000295:instrumentation / Q000379:methods; D016466:CHO Cells; D018929:Cell Culture Techniques / Q000295:instrumentation* / Q000379:methods; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical / Q000295:instrumentation* / Q000379:methods; D004594:Electrophysiology / Q000295:instrumentation / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005240:Feasibility Studies; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology; D007668:Kidney / Q000187:drug effects / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology*; D008839:Microelectrodes; D018408:Patch-Clamp Techniques / Q000295:instrumentation* / Q000379:methods; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology*; D015203:Reproducibility of Results; D012371:Robotics / Q000295:instrumentation* / Q000379:methods; D012680:Sensitivity and Specificity
chemical_list: D026902:Potassium Channel Blockers; D015221:Potassium Channels