Fig. 2
Functional assessment and maturation of human cardiopatches. a Representative isometric contractile (active) force traces of spontaneously beating hiPSC-CM cardiopatches at 1, 2, and 3 weeks of culture. b Maximum active force (left) and specific force (right) of 1, 2, and 3-week-old cardiopatches; n = 6 patches from two differentiations; *p < 0.0001, post hoc Tukey’s test. c Active and passive force–length relationships of isometrically tested (1 Hz stimulation) cardiopatches at 1, 2, and 3 weeks of culture; same patches as in b. d, e Representative isochrone activation maps (d) and average conduction velocities (CV, e) during point stimulation from bottom right corner (pulse sign) of cardiopatches at 1, 2, and 3 weeks of culture; n = 7/7/9 patches (for 1/2/3 weeks) from two differentiations; *p < 0.0001, post hoc Tukey’s test. Scale bars d, 2 mm. f Average active force, specific force, and CV in cardiopatches obtained from three additional hESC lines (Hes2, H9, and RUES2) normalized to those made of hiPSC-CMs; n = 18/37/22 patches (for Hes2/H9/RUES2) from five to seven independent differentiations per line. g, h Maximum active force (g) and specific force (h) of cardiopatches cultured for 3 weeks in 3D RB + medium or 1, 2, and 3 weeks in 5% FBS medium; n = 15/14/13/14 patches (for 3D RB+/1/2/3 weeks in 5% FBS) from five differentiations; *p = 0.0026, **p = 0.0005, ***p < 0.0001, # p < 0.001 vs. all other groups, post hoc Tukey’s test. i, j CV (i) and action potential duration at 80% repolarization (APD80, j) in cardiopatches cultured for 3 weeks in 3D RB + medium or 1, 2, and 3 weeks in 5% FBS medium; n = 15/15/14/15 patches (for 3D RB+/1/2/3 weeks in 5% FBS) from five differentiations; ***p < 0.0001, # p < 0.002 vs. all other groups, post hoc Tukey’s test. Data are presented as mean ± SEM
