Fig. 3: MSMEA continuously recorded extracellular FP and intracellular AP in cardiomyocytes.

a–e Microscopic images of 20, 50, 100, 200, and 400 μm-MEAs. f Extracellular FP and intracellular AP of typical cardiomyocytes were recorded continuously at 20 μm-MEA. g At ~36 s after micro-electroporation, the AP amplitude had decayed to 70% of its maximum value. At ~68 s after micro-electroporation, the waveforms of the recorded signals appeared characteristic of FP waveforms. At ~142 s after micro-electroporation, the recorded signals reverted to the amplitude and shape of extracellular FPs. h Extracellular FP and intracellular AP of typical cardiomyocytes were recorded continuously at 50 μm-MEA. i At ~25 s after micro-electroporation, the AP amplitude decayed to 70% of its maximum value. At ~70 s after micro-electroporation, the waveforms of the recorded signals appeared characteristic of FP waveforms. At ~229 s after micro-electroporation, the recorded signals reverted to the amplitude and shape of extracellular FP. j Extracellular FP and intracellular AP of typical cardiomyocytes were recorded continuously at 100 μm-MEA. k At ~18 s after micro-electroporation, the AP amplitude had decayed to 70% of its maximum value. At ~75 s after micro-electroporation, the waveforms of the recorded signals appeared characteristic of FP waveforms. At ~160 s after micro-electroporation, the recorded signals returned to the amplitude and shape of extracellular FP. l Extracellular FP and intracellular AP of a typical cardiomyocyte were recorded continuously at 200 μm-MEA. m At ~32 s after micro-electroporation, the AP amplitude had decayed to 75% of its maximum value. At ~53 s after micro-electroporation, the waveforms of the recorded signals appeared characteristic of FP waveforms. At ~191 s after micro-electroporation, the recorded signals reverted to the amplitude and shape of extracellular FP. n Extracellular FP and intracellular AP of a typical cardiomyocyte were recorded continuously at 400 μm-MEA. o At ~25 s after micro-electroporation, the AP amplitude decayed to 75% of its maximum value. At ~68 s after micro-electroporation, waveform features of extracellular FP began to appear in the waveform of the recorded signal. At ~197 s after micro-electroporation, the recorded signal returned to the amplitude and shape of the extracellular FP. p–s Statistical plots of (p) intracellular AP Vpp, (q) ratio of intracellular AP Vpp to extracellular FP Vpp, (R) intracellular AP duration, (s) extracellular AP and intracellular AP beat frequency. Statistical plots were analyzed for a sample size of n = 10 or 4 data per group and were expressed as mean ± sem. Significant differences were analyzed by one-way ANOVA, *, p < 0.05; **, p < 0.01; ***, p < 0.001; ****, p < 0.0001; NS, not statistically significant