(a) Brightfield images of human duodenal organoids (top) and human microvascular endothelial cells (bottom) acquired before their seeding into epithelial and endothelial channels of the chip, respectively. (b) Schematic representation of Duodenum Intestine-Chip, including its top view (left) and vertical section (right) showing: the epithelial (1; blue) and vascular (2; pink) cell culture microchannels populated by intestinal epithelial cells (3) and endothelial cells (4), respectively, and separated by a flexible, porous, ECM-coated PDMS membrane (5). (c) Scanning electron micrograph showing complex intestinal epithelial tissue architecture achieved by duodenal epithelium grown for 8 days on the chip (top) in the presence of constant flow of media (30 µl/hr) and cyclic membrane deformations (10% strain, 0.2 Hz). High magnification of the apical epithelial cell surface with densely packed intestinal microvilli (bottom). See Figure 1-figure supplement demonstrating the effect of mechanical forces on the cytoarchitecture of epithelial cells and the formation of intestinal microvilli (d) Composite tile scan fluorescence image 8 days post-seeding (top) showing a fully confluent monolayer of organoid-derived intestinal epithelial cells (magenta, ZO-1 staining) lining the lumen of Duodenum Intestine-Chip and interfacing with microvascular endothelium (green, VE-cadherin staining) seeded in the adjacent vascular channel. Higher magnification views of epithelial tight junctions (bottom left) stained against ZO-1 (magenta) and endothelial adherence junctions visualized by VE-cadherin (bottom right) staining. Cells nuclei are shown in gray. Scale bars, 1000 µm (top), 100 µm (bottom) (e) Apparent permeability values of Duodenum Intestine-Chips cultured in the presence of flow and stretch (30 µl/hr; 10% strain, 0.2 Hz) for up to 10 days. Papp values were calculated from the diffusion of 3 kDa Dextran from the luminal to the vascular channel. Data represent three independent experiments performed with three different chips/donor, total of three donors; Error bars indicate s.e.m.