Printed 3D Electrode Arrays with Micrometer-Scale Lateral Resolution for Extracellular Recording of Action Potentials

Current investigations on neuronal or cardiac tissues call for systems that can electrically monitor cellular activity in three dimensions as opposed to classical planar approaches. Typically the fabrication of such 3D microelectrode arrays (3D MEAs) relies on advanced cleanroom fabrication techniques. However, additive manufacturing is becoming an ever versatile alternative for rapid prototyping of novel sensor designs due to its low cost and material expense. Here, the possibility of fabricating high-resolution 3D MEAs is demonstrated by using electrohydrodynamic inkjet printing. The height and aspect ratio of the 3D electrodes can be readily tuned by adjusting the printing conditions and number of deposited ink droplets per electrode. The fabrication of pillar electrode arrays with electrode diameters of sintered structures below 3 µm is shown. The functionality of the array is confirmed using impedance spectroscopy and extracellular recordings of action potentials from HL-1 cells.