Real-time optogenetic control of excitation wavefronts in human cardiomyocytes using label-free and sparse sensing

Cardiac diseases are characterized by deviations from normal spatiotemporal contraction wavefront patterns. Optogenetics offers ways to investigate and mitigate these states. System integration of optogenetic control strategies requires real-time control of cardiac contractions but is often hindered by the data processing load of dense sensor arrays. To circumvent this hurdle, we extract wavefront properties label-free from spatially sparsely sampled optical signals. This allows a fast determination of the prevalent wavefront state. Besides fast measurements (~kHz), real-time control of cardiac activity requires high temporal resolution in stimulation, achieved here using ferroelectric spatial light modulators. Experiments were conducted on in vitro human induced-pluripotent-stem-cell-derived cardiomyocytes expressing the opsin f-Chrimson. We demonstrate all-optical closed-loop control of cardiac contraction wavefront shape and direction. This capability establishes a foundation for non-invasive, feedback-controlled studies of cardiac wave dynamics and may provide new insights into the mechanisms underlying excitation wavefront disturbances and mitigation strategies.