3D Nanoelectrodes for Electrophysiology: How Size Effects Seal Resistance

Abstract

Three-dimensional (3D) nanoelectrodes fabricated on standard multielectrode array architecture have proven useful in monitoring intracellular electrophysiology of cardiomyocytes. The electrodes’ mechanism of action involves a voltage pulse at the electrode which exceeds the dielectric breakdown of an engulfing cell's membrane, electroporating the cell and dramatically reducing the impedance to intracellular potential recording. The electroporation mechanism is non-invasive as the pores reseal after such recording events. This gives rise to a method which is useful in its ability to multiplex, its technical ease of use, and non-invasiveness.The driving phenomenon which gives this technological gain over planar electrodes is an enhancement of the seal resistance between the electrogenic center (the cell) and the recording center (the nanoelectrodes). Cells in vitro engulf 3D electrodes such that the membrane-electrode distance is much reduced compared to that of the membrane-planar electrode distance. This membrane-electrode distance is dependent upon the geometry of the electrode, but the electrical ramifications of this have not been characterized to date. Herein we explore this dependence by using electrochemical impedance spectroscopy in correlation with reduced-artifact FIB/SEM and electrophysiological measurement of HL-1 cardiomyocytes over an order of magnitude in 3D electrode diameter.