This chapter presents a comprehensive description of the structure and properties of the basic types of conductive polymers (CPs), and their applications in development of sensors and biosensors, including immunosensors, aptasensors, pH nanosensors, enzyme biosensor, noses, and tongues. Furthermore, due to the important role of miniaturized sensor systems used in both the future development of medical devices and biomedical research, CP-based nanoscale sensors are also presented. CPs have unique properties, especially the easy modification of their chemical, electrical, structural, and physical properties. The application of CP nanomaterials has grown significantly in various fields including in the fields of environmental science, medicine, and energy. Moreover, CP-based sensors have interesting features such as good stability, high sensitivity, and low weight. On the other hand, the nanoscale sensors are somewhat less common in the literature due to their high cost and the complexity they produce. Thus, to improve the sensor performance, various nanoscale materials such as metals, metal oxides, carbon materials, and polymers, have been used in the design and fabrication of sensors or biosensors. The efficient integration of nanoscale materials with CPs has been very promising, and CP-based sensing devices can act as multiple sensors and wearable biosensors, while also facilitating the expansion of point-of-care and implantable sensing devices. The integration of CPs with nanomaterials in the development of sensors and biosensors has attracted greater attention due to their excellent performance.
