Automated current clamp of native cells expressing physiological levels of ion channels enables phenotypic screening and multiple ion channels, safety assessment. The newly released current clamp mode for automated patch clamp system, QPatch, automates action potential measurement and is a significant expansion of the automated electrophysiology toolset.
Stem cell-derived cardiomyocytes or induced pluripotent stem cell (iPSC) derived cardiomyocytes have many of the phenotypic properties of authentic cardiomyocytes e.g. realistic ventricular action potentials and are powerful cellular models for action potential based screening of compounds.
Following gigaseal and whole cell access formation, QPatch command protocol is switched to current clamp mode where membrane current is controlled and membrane voltage is measured. In this work we show how the QPatch can trigger action potentials using rapid switching from voltage to current clamp during recordings on the iPS derived cariomyocytes. We demonstrate that the current clamp recordings made on this automated patch clamp device are comparable to results obtained on standard manual patch clamp rigs. Parallel recordings from up to 48 iPS derived cardiomyoyctes are made on QPatch with full analysis of action potential features including action potential duration, upstroke velocity. We measured assay success rates, the stability of action potentials and pharmacological profiles of reference compounds. Current clamp measurements of these cardiomyocytes offer important information to the understanding of the complex pharmacological effect of compounds on ion channels involved in the action potential. Data presented here clearly demonstrate how automated patch clamp on QPatch can augment the throughput of current clamp to meet new demands in drug discovery.