Transparent Graphene Interfaces for Capacitive Recordings from hiPSC-Derived Cardiomyocyte Monolayers: A Proof-of-Concept Study

Transparent conductive interfaces can enable optical pre-assessment of cardiac cell layers while remaining compatible with label-free electrophysiological recording. Here, we evaluated the integration of a monolayer graphene electrode into a capacitive recording platform for the analysis of human-induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) monolayers. hiPSC-CMs cultured on graphene sensors formed confluent, synchronously beating monolayers that could be assessed by light microscopy prior to recording. Capacitive current transients could be recorded from spontaneously beating hiPSC-CM monolayers, supporting the compatibility of transparent graphene interfaces with capacitive recordings from electrically active cardiac cell layers. Signal amplitude and waveform morphology varied across sensors, indicating that recording performance depended strongly on the cell–sensor interface, including cell attachment, monolayer integrity, and capacitive coupling at the sensing surface. A descriptive perturbation sequence using the hERG blocker dofetilide revealed changes in waveform morphology and beat timing across sequential recordings. However, the data do not allow firm attribution to a compound-specific effect and are not intended for quantitative pharmacological characterization. Overall, the results support graphene as a transparent conductive cell–sensor interface, which should be interpreted in the context of cell–substrate interactions at the sensing surface. Combining optical pre-assessment with functional capacitive readout may support integrated workflows. Further studies will be needed to differentiate material-, interface-, and recording-related contributions and to establish reliable conditions for reproducible and scalable recordings.