Planar Patch Clamp System Capable of Recording Mechanosensitive Activity of Ion Channels

Abstract

Response to mechanical stimuli, which includes proper development of biological tissues and organs, is essential to the cell. Mechanosensitive ion channels are the basic elements among mechanosensing molecules and complexes. Although the traditional patch clamp technique using glass micropipettes is still widely used for electrophysiology, it is difficult to control the mechanical stimulus to ion channels in this system. Here we developed a novel patch clamp system with a planar stretchable electrode to record mechanosensitive responses of ion channels. Planar electrodes of 100 μm thickness were fabricated using silicone resin. Next, we prepared HEK293 cells transfected with the stretch-activated KCa (SAKCA) channel, which is mechanosensitive, for planar patch clamp recordings. Using our planar patch clamp system, a gigaohm seal was achieved with a maximum seal resistance of 10 GΩ. The success rate of gigaohm seal formation was 37%. Then we recorded single channel currents with a slope conductance of 285.4 pS, which is parallel to the known SAKCA current. Using scanning electron microscope, we confirmed elongation of the aperture by 37.7% when 50% stretch was applied to the planar electrode. It is expected that a controllable and sufficient stretch stimulus can be applied to the cellular membrane using our newly developed planar patch clamp system.