Direct measurement and stimulation of electrophysiological activity is a staple of neural and cardiac health monitoring, diagnosis and/or therapy. Such bi-directional interfacing can be enhanced by the low impedance imparted by organic electronic materials that show mixed conduction properties (both electronic and ionic transport). Many high performance bioelectronic devices are based on conducting polymers such as poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS. By investigating PEDOT-based materials and devices, we are able to establish a set of design rules for new formulations/materials. Introducing glycolated side chains to carefully selected semiconducting polymer backbones, for example, has enabled a new class of high performance bioelectronic materials that feature high volumetric capacitance, transconductance >10mS (device dimensions ca. 10um), and steep subthreshold switching characteristics. A sub-set of these materials outperform PEDOT:PSS and shows significant promise for biocompatible, low power in vitro and in vivo biosensing applications.
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