Planar Patch-Clamp Electrodes for Single Cell and Neural Network Studies

The traditional glass pipette patch-clamp technique has contributed greatly to fundamental and pharmacological ion channel studies. The success of this serial technique has driven an effort to create wafer-based patch-clamp platforms using materials with inferior dielectric properties than glass and/or using exotic processing techniques to avoid the difficulties inherent to parallel processing of glass. We have developed a material processing scheme that generates ultrasmooth, high aspect ratio pores in fused quartz wafers. These devices are demonstrated here to be superior planar patch-clamp electrodes achieving gigaohm seals in nearly 80% of trials with a mammalian cell line, with the majority of seals over 10 GΩ and as high as 80 GΩ, competing with the best pipette-based patch-clamp measurements. Our method, amenable to batch fabrication technologies, will enable the acquisition of low noise, ion channel measurements in high throughput.We are currently merging the abovementioned devices with voltage sensitive dye (VSD) imaging and multi-electrode array (MEA) recordings in order to study multisensory integration in the medicinal leech. Initially, the planar pores will function to provide precise placement of neurons in the leech ganglion over the MEA's. The excellent spatial resolution of the VSD's combined with the temporal resolution of MEA's will provide much information of all the neurons that respond to visual stimuli in the ganglion. Further studies may employ the planar pores as intracellular electrodes, allowing voltage control and intracellular recordings of individual neurons in the ganglion.