Flexible Microelectrode Arrays Based on Vacuum Filling for Electrophysiology Sensing of Cardiomyocytes

Microelectrode arrays (MEAs) are widely used platforms for the electrophysiological monitoring of cardiomyocytes, providing an effective method to enhance the efficiency of drug development and analyze disease models. However, traditional MEAs are fabricated on rigid silicon or glass substrates, which causes a huge mismatch of the modulus with myocardial tissue. In this work, we proposed a vacuum filling technology of the bismuth–indium (Bi–In) alloy for flexible MEA fabrication. The vacuum filling was realized at an elevated temperature inside polydimethylsiloxane microchannels when Bi–In was in its liquid state. Then, Bi–In then underwent a phase transition to form solid-state electrodes when returned to room temperature. The fabricated Bi–In MEA showed good flexibility, which could resist bending (180°), and had an electrochemical impedance of 174.3 kΩ at 1 kHz when the electrode diameter is 50 μm. The devices were demonstrated for recording electrophysiological signals from human-induced pluripotent stem cell-derived cardiomyocytes, which presented excellent biocompatibility, and were able to detect typical field potential waveforms with amplitudes of >900 μV. This work presents an approach in the advancement of flexible MEA fabrication and serves as a robust tool for application in preclinical drug analysis.