Extracellular Potentials Measurement Using MEA

Extracellular potentials were measured using a self-made 64-channel MEA system as described before [17 (link),18 (link)]. The MEA system was set at a sampling rate of 100 kHz with a low path filter of 2 kHz and a high path filter of 10 Hz, and signals were amplified by 5000 using an analog amplifier. The MEA chips with cardiomyocyte networks were set in the chip holder of the field potential (FP) measurement device on the stage of the inversed optical microscopy (IX-71 with an x10 phase-contrast objective lens, UPLFLN10X2PH, OLYMPUS, Tokyo, Japan) and incubated at 37 °C in 5% CO₂.