Figure 4

Electrical competence of cardiac cells within scaffolds. a Fluorescent image of voltage sensitive dye and corresponding b optical action potential of human cardiomyocytes within 3D human heart ECM scaffold. Still images of beating cardiomyocytes in c 2D culture, and in 3D scaffolds seen d fluorescently and e in Brightfield. Corresponding videos can be found in Additional files 2, 3, 4: Video 1, 2A, 2B, respectively. Cardiomyocytes maintained sufficient intercellular connections that enabled the scaffolds to contract as a single unit. Microelectrode array recordings of field potentials from human cardiomycoyte-seeded scaffolds f before and g after isoprenaline (Videos are found in Supplementary Videos 3A and 3B, respectively). Addition of isoprenaline heightened the amplitude and increased the beat rate 27%.