Recent advances in three-dimensional microelectrode array technologies for in vitro and in vivo cardiac and neuronal interfaces

Three-dimensional microelectrode arrays (3D MEAs) have emerged as promising tools to detect electrical activities of tissues or organs in vitro and in vivo, but challenges in achieving fast, accurate, and versatile monitoring have consistently hampered further advances in analyzing cell or tissue behaviors. In this review, we discuss emerging 3D MEA technologies for in vitro recording of cardiac and neural cellular electrophysiology, as well as in vivo applications for heart and brain health diagnosis and therapeutics. We first review various forms of recent 3D MEAs for in vitro studies in context of their geometry, materials, and fabrication processes as well as recent demonstrations of 3D MEAs to monitor electromechanical behaviors of cardiomyocytes and neurons. We then present recent advances in 3D MEAs for in vivo applications to the heart and the brain for monitoring of health conditions and stimulation for therapy. A brief overview of the current challenges and future directions of 3D MEAs are provided to conclude the review. •This manuscript reviews the state-of-the-art technologies of three-dimensional microelectrode arrays for in vitro analyses of cardiac and neural cell electrophysiology.•Structural, material properties and fabrication of 3D MEAs for in vitro applications are detailed.•Recent development in in vivo 3D MEAs for the heart or brain diagnosis or clinical therapy are discussed.•Recent developments and demonstrations of 3D MEAs for in vitro cardiac/neural cell monitoring are reviewed.•Recent advances in 3D MEAs for in vivo applications for signal detection and stimulation are delineated.