Intracellular recording of cardiomyocyte action potentials by nanobranched microelectrode array.

Electrophysiological study that records the action potential of cardiomyocyte served as excellent tool to explore cardiology and neuroscience, disease investigation and pharmacological screening. Advances of micro/nanotechnologies promote the development of three-dimensional (3D) nanodevices to record high-quality intracellular recordings by various perforation approaches of cells, however, the complicated fabrication processes limited their large-scale manufacture. In this work, a unique nanobranched microelectrode array (NBMEA) platform is developed to achieve high-quality intracellular recording of cultured cardiomyocytes in a minimally invasive manner. The NBMEA is consisting of high aspect ratio conductive nanobranches fabricated on patterned microelectrodes combining hydrothermal growth and standard microfabrication. The 3D structure of nanobranches enables the electrode to form tight coupling with cardiomyocytes to achieve the low voltage cell electroporation and high-quality intracellular recording. The recorded intracellular action potentials of cardiomyocytes by NBMEA exhibited significant enhancement on amplitude (~5 mV), signal-to-noise ratio (SNR) (~67.47 dB), recording duration (up to 105 min), and recording yield (69.5 ± 17.8%). This NBMEA platform is a promising and powerful tool for electrophysiology that opens up new opportunities for high-quality and stable intracellular recording of cardiomyocytes.