Butterfly wing-inspired high-bandwidth heart-on-a-chip reveals hidden mechanical dynamics of cardiomyocytes

Cardiovascular disease remains a leading cause of mortality worldwide, driving the need for novel platforms that capture both the electrical and mechanical facets of cardiac function. While high-resolution electrophysiological techniques, such as patch clamp and microelectrode arrays, provide detailed insights into the electrical activity of cardiomyocytes, methods to accurately resolve their mechanical contractility are still limited. Conventional heart-on-a-chip devices typically employ sensors with low bandwidth and high damping, which distort the fine-scale mechanical signals critical to understanding excitation-contraction coupling. Here, we present a novel, butterfly wing-inspired heart-on-a-chip platform that incorporates a carbon nanotube (CNT)/polymethylmethacrylate (PMMA)-based strain sensor fabricated via direct ink writing, achieving a bandwidth of 22.85 Hz. This enhanced capability enables high-fidelity, multi-frequency detection of cardiomyocyte contractile waveforms, revealing previously undetectable features such as secondary peaks and rapid strain transitions. Our approach provides a complementary tool to existing electrophysiological methods, paving the way for improved mechanistic insights and more precise drug screening in cardiovascular research.