Planar transistor array systems for extracellular recordings

An extracellular recording system has been designed for the detection of electrical cell signals. A field-effect transistor (FET) array has been fabricated which consists of p-channel or n-channel FET´s with nonmetallized gates. The size of the gates of the 16 FET´s are from 16×3 μm² down to 5×1 μm² and are arranged in a 4×4 matrix on 200 and 100 μm centers. On the other side extended gate electrode (EGE) arrays were used which are arranged in a 8×8 matrix, on 200 and 100 μm centers. The gate electrodes are made from gold, titanium and silicides with diameters down to 6 μm. The cell-device coupling has been studied using various cell types e.g. neuronal cells, cardiac myocytes, and cells from cell lines. The recorded signals will be discussed on the base of a simple point contact model where contributions from passive as well as active membrane properties are included