FIGURE 1.

(A) Illustration of an early human embryo. Heart (H: red) beating confers mechanical stimulation to the surrounding cells, and hepatic endoderm (HE: blue), which differentiates to hepatoblasts, is exposed to mechanical forces. (B,C) Appearance (B) and cross-section (C) of a microfluidic device for applying a series of stretching stimulations to hepatic endoderm-like cells (HECs). (D) Cross-sectional view of the device, composed of polydimethylsiloxane (PDMS) and consists of a top layer with cell-culture chambers, middle membrane layer, and bottom layer with pressure chambers on a glass slide. (E) Photograph of our device fabricated on a glass slide (25 × 75 mm). Culture chambers are filled with red ink. This device has two sets of culture chambers in which cells are cultured under the same intensity of mechanical stimulation. (F) Photograph of a microfluidic device. Microfluidic channels and pressure chambers filled with green ink.