Dual-modality imaging system for monitoring human heart organoids beating in vitro

To reveal the three-dimensional microstructure and calcium dynamics of human heart organoids (hHOs), we developed a dual-modality imaging system combining the advantages of optical coherence tomography (OCT) and fluorescence microscopy. OCT provides high-resolution volumetric structural information, while fluorescence imaging indicates the electrophysiology of the hHOs' beating behavior. We verified that concurrent OCT motion mode (M-mode) and calcium imaging retrieved the same beating pattern from the heart organoids. We further applied dynamic contrast OCT (DyC-OCT) analysis to strengthen the verification and localize the beating clusters inside the hHOs. This imaging platform provides a powerful tool for studying and assessing hHOs in vitro, with potential applications in disease modeling and drug screening.