Organic Bioelectronic Materials for Health Monitoring

Measuring local electrophysiological activity is a staple of neural and cardiac health monitoring and is important for diagnosis of pathological conditions. The ability to sensitively detect these signals can be enhanced by organic electronic materials that show mixed conduction properties (both electronic and ionic transport) in order to bridge the inherent mismatch between the worlds of biology and microelectronics. Organic electrochemical transistors (OECTs) are one class of devices that utilize organic mixed conductors as the transistor channel, and have shown considerable promise as amplifying transducers due to their stability in aqueous conditions and high transconductance. These devices are fabricated in flexible, conformable form factors for in vivo recordings of epileptic activity, and for cutaneous EEG and ECG recordings in human subjects. By understanding the application-dependent performance and device physics of OECTs, we develop design rules for new formulations/materials. These efforts have led to a new class of high performance OECT materials that feature transconductance >10mS (device dimensions ca. 10um), as well as steep subthreshold switching characteristics for low power sensing applications.