Dual-organoid biosensor for monitoring cardiac conduction disturbances in vitro

Accurate detection of conduction disorders, a critical factor for arrhythmogenic risk assessment, is a key challenge in drug development and cardiovascular safety screening. This study presents a highly sensitive atomic force microscopy (AFM)-based biosensor using a dual-beating human pluripotent stem cell (hPSC)-derived organoid to discriminate between focal and conductive arrhythmic contractions. Analysis of the variance of the regression residuals revealed increased stochastic (random) fluctuations in unsynchronized clusters, indicative of arrhythmic instability. Mechanosensing assessed by force microscopy allows the differentiation of the vertical and lateral direction of contractile movement. The high biosensor sensitivity allowed detailed analysis of contractile behavior under pharmacological modulation with cardiomodulating drugs. Moreover, heptanol-induced arrhythmias were associated with inhibition of atrioventricular conduction, demonstrating the ability of the system to model mechanisms of conduction blockade. For the first time, an AFM-based transducer successfully discriminates focal from conductive arrhythmias, marking a significant advance in vitro cardiac biosensing. The dual organoid system enhances model robustness by reducing the variability inherent in single-cell studies, thereby improving translational relevance for cardiotoxicity assessment and precision medicine applications in cardiovascular health.