Organic electrochemical transistors based on PEDOT:PSS: biocompatible devices to sense the cells metabolism and drug activity

The interest towards organic materials for the realization of devices for its flexibility, low cost and chemical engineering have attracted a great deal of attention [1]. Between the different possible applications sensing could play a crucial role in use of these materials and of particular interest is the possibility to use these materials as sensors in water solution. For these reasons since the 1980's organic electrochemical transistors (OECTs) have attracted a great deal of interest for biosensor applications [2].The basic structure of OECTs consists of two stripes of conducting polymeric film in contact with the electrolyte solution [3]. The working principle is practically the same of two electrochemical electrodes but with the great advantage due to that the current that flows in one electrode could be modulated by the potential applied to the other electrode [4]. This is the gate electrode and controls the doping level of the conducting polymer inside the other electrode. OECTs can be operated in aqueous electrolytes, providing an interface between the worlds of biology and electronic materials. The inherent signal amplification of OECTs has the potential to yield sensors with low detection limits and high sensitivity. The vision is to build a disposable "lab on a chip", a diagnostic device consisting of multiple sensors, where one can input a drop of analyte and receive an analysis of as many indicators of health as possible.