Abstract: The present invention relates to a substrate for measuring the electrophysiological properties of ion-channels located in cell membranes. The substrate is typically used in a screening device providing high-throughput industrialized measurements for studying ionic currents, particularly useful in the screening of drugs acting on the ion-channels found in cell membranes, by providing many parallel simultaneous and independent measurements. The substrate has one or a plurality of individually addressable electrode sites, each comprising one or more individual elongated nanosize electrodes, capable of penetrating the cell membranes during application of cells directly on the substrate, thus providing one or more low resistance contacts to the interior of the cells. This allows for an easy and effective low-cost solution to automated patch clamp measurements in the whole-cell configuration, using both single as well as multi-electrode contacts to each cell.