Patch clamping on plane glass - Fabrication of hourglass aperture and high-yield ion channel recording

Planar patch-clamp has revolutionized ion-channel measurement by eliminating laborious manipulation from the traditional micropipette approach and enabling high throughput. However, low yield in gigaseal formation and/or relatively high cost due to microfabricated processes are two main drawbacks. This paper presents patch clamping on glass substrate - an economical solution without sacrificing gigaseal yield rate. Two-stage CO₂ laser drilling methodology was used to generate an hourglass, funnel-like aperture of a specified diameter with smooth and debris-free surfaces on 150 m borosilicate cover glass. For 1-3 m apertures as patch-clamp chips, seal resistance was tested on human embryonic kidney, Chinese hamster ovary, and Jurkat T lymphoma cells with a gigaseal success rate of 62.5%, 43.6% and 66.7% respectively. Results also demonstrated both whole-cell and single channel recording on endogenously expressed ion channels to confirm the capability of different patch configurations.