Continuous measurement of surface electrical potentials from transplanted cardiomyocyte tissue derived from human-induced pluripotent stem cells under physiological conditions in vivo

Recording the electrical potentials of bioengineered cardiac tissue after transplantation would help to monitor the maturation of the tissue and detect adverse events such as arrhythmia. However, a few studies have reported the measurement of myocardial tissue potentials in vivo under physiological conditions. In this study, human-induced pluripotent stem cell-derived cardiomyocyte (hiPSCM) sheets were stacked and ectopically transplanted into the subcutaneous tissue of rats for culture in vivo. Three months after transplantation, a flexible nanomesh sensor was implanted onto the hiPSCM tissue to record its surface electrical potentials under physiological conditions, i.e., without the need for anesthetic agents that might adversely affect cardiomyocyte function. The nanomesh sensor was able to record electrical potentials in non-sedated, ambulating animals for up to 48 h. When compared with recordings made with conventional needle electrodes in anesthetized animals, the waveforms obtained with the nanomesh sensor showed less dispersion of waveform interval and waveform duration. However, waveform amplitude tended to show greater dispersion for the nanomesh sensor than for the needle electrodes, possibly due to motion artifacts produced by movements of the animal or local tissue changes in response to surgical implantation of the sensor. The implantable nanomesh sensor utilized in this study potentially could be used for long-term monitoring of bioengineered myocardial tissue in vivo under physiological conditions.