Polyaniline-Based Biological and Chemical Sensors: Sensing Mechanism, Configuration Design, and Perspective

By virtue of its tunable electrical conductivity, remarkable solution processing capability, and great biocompatibility, polyaniline (PANI) has been recognized as an attractive active material for use in biological and chemical ("bio/chemical") sensors. This Spotlight article focuses on the structure and characteristics of PANI-based materials and the corresponding device-level sensing performance. PANI-based bio/chemical sensors, such as chemi-resistive sensors, electrochemical sensors, and transistor-based sensors, are systematically elucidated based on device architecture and sensing mechanism. The corresponding structure–function relationships among PANI doping state, microscopic structure, local crystallinity, and their functionalities in three types of sensors have been systematically elaborated. Finally, the state-of-the-art progress in applications of these sensors and the corresponding breakthroughs in a broader context are outlined from the challenges to strategies.