This thesis reports on a novel system forextracellular recordings of the activity of excitable cells, which relies on anorganic, charge-modulated field-effect transistor (FET) called OCMFET. Thebook shows how, thanks to the intrinsic biocompatibility, lightness, andinexpensiveness of the material used, this new system is able to overcome severalproblems typical of of “classic” electronic andbioelectronic. Itprovides a full description of the system, together with a comprehensive reportof the successful experimental trials carried out on both cardiac and nervecells, and a concise yet comprehensive overview of bioelectronic interfaces andorganic sensors for electrophysiological applications.