A) EBs differentiated into mesoderm, showing characteristic morphology of a confluent cardiac lineage. (B-C) EBs differentiated into functional mesoderm, showing contractile cardiac muscle. Contraction rate frequency increased over time during in vitro differentiation. (B) Initially, the rate was 50 contractions per minute (cpm) at 14 days of in vitro differentiation induction (see supplemental file Video005). (C) Contractions increased to 70 cpm after 30 days of in vitro differentiation induction (see supplemental file Video007). Phase contrast images are at a magnification of 10X.

Figure 8: Embryoid bodies from the H7 ES cell line differentiated into cardiac muscle tissue (early mesoderm) 14 days after in vitro differentiation induction.