Photoelectrochemical imaging of action potentials for single cardiomyocytes through contact force manipulation of organoids

Accurate monitoring of cardiomyocyte action potentials (APs) is essential to understand disease propagation and for trials of novel therapeutics. Patch clamp techniques offer gold standard measurements in this field, but are notoriously difficult to operate and only provide measurements of a single cell. Here we propose photoelectrochemical imaging (PEI), in conjunction with a setup for controlling the contact force between the cardiomyocyte organoids and the sensor surface, for measuring APs with high sensitivity. The method was validated through the use of drugs, and the results successfully visualized the expected electrophysiological changes to the APs. PEI allows for several cells to be monitored simultaneously, opening further research to the electrophysiological interactions of adjoining cells. This method expands the applications of PEI to three-dimensional geometries and provides the fields of stem cell research, drug trials and heart disease modelling with an invaluable tool to further investigate the role of APs.