Figure 6.

Hierarchical vasculature supports iPSCs‐derived cardiomyocytes. A) iPSC‐derived cardiomyocytes printed in rhCollMA cluster and display characteristic sarcomere striated patterns (cTnI, red; scale bar: 20 µm). B) Bioprinted GCaMP‐CMs spontaneously beat and develop electromechanical communications, evidenced by calcium transients (green) traveling distances over 1 mm (scale bar: 200 µm). C‐i) Schematic describing the assembled and cultured vascularized cardiomyocytes constructs. ii) Confocal image showing the presence of vascular networks (CD31, green) and cardiomyocytes (cTnI, red) after seven days in vitro (scale bar: 100 µm). D) Cardiomyocytes chronotropic behavior responses to isoproterenol. i) Representative line‐scan images showing the GCaMP‐CMs intracellular Ca+2 transients before and after isoproterenol was added to the culture medium. ii) Comparison of the average beats per minute and Ca⁺² transients decay time between vascularized cardiac constructs in regular culture medium (baseline) and isoproterenol‐supplemented medium (iso). N > 4, *p < 0.05, ****p < 0.0001.