Cell to aperture interaction in patch-clamp chips visualized by fluorescence microscopy and focused-ion beam sections

Patch‐clamp is an important method to monitor the electrophysiological activity of cells and the role of pharmacological compounds on specific ion channel proteins. In recent years, planar patch‐clamp chips have been developed as a higher throughput approach to the established glass‐pipette method. However, proper conditions to optimize the high resistance cell‐to‐probe seals required to measure the small currents resulting from ion channel activity are still the subject of conjecture. Here, we report on the design of multiple‐aperture (sieve) chips to rapidly facilitate assessment of cell‐to‐aperture interactions in statistically significant numbers. We propose a method to pre‐screen the quality of seals based on a dye loading protocol through apertures in the chip and subsequent evaluation with fluorescence confocal microscopy. We also show the first scanning electron micrograph of a focused ion beam section of a cell in a patch‐clamp chip aperture. Biotechnol. Bioeng. 2011; 108:1936–1941. © 2011 Wiley Periodicals, Inc.