FIG. 1.

The cup-like coculture system was manufactured by microfluidic technologies. Color picture of empty polydimethylsiloxane with enlarging the details of multiple channels (A). Schematic diagram of microfluidic device exhibited the feature similar to the Bowman's capsule in kidney (B). The adipose stem cells were embedded in the collagen gel (CG-ASC) and injected into the central channel. After polymerization of CG-ASC, the suspending kidney epithelial cells (MDCKs) were applied to the peripheral channel and formed a monolayer. A clear interface between the three-dimensional environment of CG-ASC and the epithelial monolayer of MDCKs was observed after coculture for 24 h (C). The dash line shows the estimate border to confine CG-ASC by the surface tension of gel. Scale bar in (A)=1 cm. Scale bar in (C)=400 μm. MDCK, Madin-Darby canine kidney.