3D Printed Implantable Hydrogel Bioelectronics for Electrophysiological Monitoring and Electrical Modulation

Abstract Electronic devices based on conducting polymer hydrogels have emerged as one of the most promising implantable bioelectronics for electrophysiological monitoring and diagnosis of a wide spectrum of diseases, in light of their distinct conductivity and biocompatibility. However, most conducting polymer hydrogels‐based bioelectronics are routinely fabricated through conventional techniques, which are challenged by its intrinsic poor processability of conducting polymers, as well as the essentially fragile biointerface, thus hampering their rapid innovation and application in advanced implantable bioelectronics. Here, 3D printable hydrogels based on poly(3,4‐ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) is reported, featuring superior 3D printability for direct ink writing (DIW), tissue‐like mechanical compliance (Young's modulus of 650 kPa), instant and tough bioadhesion (interfacial toughness of 200 J m −2 and shear strength of 120 kPa), highly‐tunable electrical properties, as well as long‐term in vitro and in vivo structural and electrochemical robustness. Electro‐physiological studies rat heart models with normal or arrhythmic conditions highlight the capabilities of establishing conformal biointerface with the dynamic organs, allowing for long‐term and high‐precision spatiotemporary epicardial electrophysiological monitoring, as well as electrical modulation of acute myocardial infarction (MI) model. These advances provide a promising strategy to improve the tissue‐electronics interfacing, and could serve as the basis for the next generation bioelectronics toward healthcare monitoring, diagnosis and medical therapies.