Stirred suspension culture in the bioreactor system creates a large number of EBs.

<p>(A) Representative image of EBs at 3 days of culture in the bioreactor system. Original magnification, ×10. (B) The number and diameter of EBs in the culture vessel at 3 days. (C, D) The cardiac differentiation potential of EBs created using the bioreactor system. (C) At 7 days after adherent culture of EBs created using the bioreactor system, some EBs expressed GFP. The upper panel is a merged image of phase contrast and fluorescence images. The lower panel shows GFP expression. Scale bars, 500 µm. (D) GFP(+) cells in EBs expressed several cardiac contractive proteins (red) including cardiac troponin T (cTnT, left) and sarcomeric α-actinin (right) in a fine striated pattern. Nuclei were counterstained with DAPI (blue). Scale bars, 20 µm.