Figure 3.

Formation of a polarized colonic epithelium within the Colon Chip. (A) Immunofluorescence confocal microscopic images of histologic cross-sections of the Colon Chip (left) compared with human colon in vivo (right) showing a polarized epithelium with tight junctions labeled with zonula occludens 1 (ZO1) (green) and brush border stained for F-actin (gray) restricted to the apical regions, and Hoechst-stained nuclei (blue) localized at the cell base. Images are representative of 3 independent experiments. Scale bars: 50 μm. White dashed line indicates the top of the porous PDMS membrane in the Colon Chip. (B) Cross-sectional immunofluorescence confocal microscopic images of the Colon Chip (left) compared with human colon in vivo (right) showing a polarized epithelium with basolateral adherens junctions labeled with E-cadherin (green) and brush border stained for F-actin (gray) restricted to the apical regions, and Hoechst-stained nuclei (blue) localized at the cell base. Images are representative of 3 independent experiments. Scale bars: 50 μm. (C) Intestinal barrier function of the colonic epithelium measured over 14 days of culture on-chip by quantifying the apparent permeability (P_app) of Cascade blue (550 daltons) (n = 3–11 chips). ****P < .0001 compared with day 2. (D) Quantification of cell growth by measuring EdU incorporation over 18 hours using flow cytometry (n = 6–8 chips, 2 independent experiments compiled). *P < .05 compared with day 3 and day 7. All data represent means ± SEM.