Enhanced intracellular recording in cardiomyocytes via soft ionic–electronic conductive interfaces of PEDOT: PSS-modified electrodes

Precise recording and stimulation of cardiomyocyte electrical activity with high spatiotemporal resolution is critical for understanding cardiac electrophysiology and associated pathologies. Here, we present a high-performance soft conductive polymer interface based on poly (3,4-ethylenedioxythiophene): polystyrene sulfonate (PEDOT: PSS)-modified electrodes for reliable intracellular electrophysiological recording. The electrodes are fabricated using standard microfabrication followed by electrochemical electropolymerization of PEDOT: PSS, a conductive polymer known for its mixed ionic-electronic conductivity, biocompatibility, and mechanical softness. Compared to bare Au electrodes, PEDOT: PSS-modified electrodes exhibit significantly reduced impedance, enhanced charge storage capacity, and improved electrode–cell coupling. Primary cardiomyocytes cultured on the modified surfaces show robust adhesion and high viability. Using a self-developed biosensing-regulating electrophysiological system, PEDOT: PSS-modified electrodes enable repeated intracellular action potential recordings with high amplitude, high signal-to-noise ratio, and stable waveforms across multiple electroporation cycles and over 5 days. These findings demonstrate the potential of PEDOT: PSS-modified electrodes as minimally invasive, high-fidelity bioelectronic interfaces for cardiac electrophysiological research, high-throughput drug screening, and future implantable biomedical applications.