Organic Electrochemical Transistors in Bioanalytical Chemistry

The detection of pathogens in low concentrations is a major challenge. Electrochemical biosensor provide a viable solution because they are low cost, fast, and miniaturized. However, due to the complexity of biological samples, there is a need to create devices that enable signal amplification, which are more sensitive, specific, and biocompatible. Organic electrochemical transistors (OECTs) are an important technological alternative to be applied in diagnosis area. Transistors measure the intensity of the electrical current that flows between the source and drain electrodes that is proportional to an electric field applied to a third electrode, called gate. OECTs use small organic molecules and conjugated macromolecules as semiconductors, in addition to an electrolytic layer, which allows biosensing applications. They are promising for the analysis of electroactive biological species, which can be directly reduced or oxidized at the electrode interface. Further, redox inactive biological species may be analyzed through molecular biorecognition. Due to the unique characteristics of signal amplification, OECTs are an option for the development of a wide range of customized point-of-care test tools for clinical diagnosis and therapeutic applications.