Photovoltaic Stimulation Induces Overdrive Suppression in Embryonic Chicken Cardiomyocytes

In this study, we employed calcium imaging to investigate the dynamics of intracellular calcium levels in embryonic chicken cardiomyocytes upon extracellular, optoelectronic stimulation. A photovoltaic layer of donoracceptor pigments on a flexible PET substrate was used as a wireless stimulation electrode. Our findings revealed a distinct change in their spontaneous activity pattern in cardiac cells following asynchronous light stimulation. A short pause in cellular activity, indicative of overdrive suppression, was observed in recordings from several different cells. The pause in activity signifies a transient refractory period induced by stimulation of the photovoltaic device with red light. These findings suggest that photovoltaic electrodes can be used to effectively modulate the electrical activity of cardiac cells in a wireless, non-pharmacological manner. This opens new avenues for non-invasive and precise light-modulated control of cellular electrophysiology as well as potential therapeutic applications for cardiac rhythm disorders.