Fig. 2.

Maturation of electrophysiological and contractile properties are determined by the tissue-engineered environment. (A) Representative individual contraction curves and contraction parameters of hCOs in CTRL medium or MM. (B) Isoprenaline stimulation induces an increased rate of contraction in hCOs; n = 5–7. (C) Isoprenaline increases the force of contraction in hCOs cultured in MM; n = 5–7 from two experiments. (D) hCOs cultured in MM have decreased calcium sensitivity. As isoprenaline stimulation experiments were performed in culture medium (Ca²⁺ = 1.8 mM), the effects of isoprenaline may be more pronounced at lower calcium concentrations; n = 4–7 from two experiments. (E) Isoprenaline increases force of contraction and decreases contraction duration under paced conditions (1 Hz) at the calcium EC₅₀ (CTRL = 0.3 mM, MM = 1.0 mM); n = 7. (F) Representative individual calcium indicator (Fluo-4) recordings and parameters from individual hPSC-CMs dissociated from hCOs cultured in CTRL medium or MM paced at 1 Hz at 37 °C. (G) Representative individual action potential recordings and parameters from individual hPSC-CMs dissociated from hCOs cultured in CTRL medium or MM paced at 1 Hz at 37 °C. Data are mean ± SEM. The response curves to calcium of hCO in CTRL medium and MM are statistically significant using two-way ANOVA (P < 0.05) (D). APD, action potential duration; CMP, clamped membrane potential; RMP, resting membrane potential. *P < 0.05; **P < 0.01; ***P < 0.001; and ****P < 0.0001 using t test (A and E), two-way ANOVA (indicates difference relative to baseline; B and C), or ANOVA with Tukey’s posttest (F and G).