Figure 5.

Observation of five-layered human iPS cell-derived cardiac cell sheets by optical coherence tomography (OCT). Just after layering of a fifth cardiac cell sheet onto the four-layered cardiac cell sheets and subsequent centrifugation, the lower cell sheets beat synchronously (a). The beating of the lower cardiac cell sheets was also occasionally transmitted to the upper cardiac cell sheets (b). Within 60 min after centrifugation, the five-layered cardiac cell sheets showed synchronous beatings (c). The time-intervals between (a-1) and (a-4), (b-1) and (b-6), or (c-1) and (c-5) were 1.6 s, 1 s, or 1 s, respectively. Beating areas within the cell sheet are shown with green colors. (c) The white arrowheads indicate the initiation sites of the beatings within each section of the tissue. In (c-1) the multilayered cardiac sheets are outlined with dashed lines. An OCT system (IVS-2000) was used in this study.