Fig. 2. Epithelialization of the scaffolds. A. The unit consists of one villus and six crypts. Three hours after seeding the organoids on the collagen scaffold in the presence of mouse intestinal fibroblasts. Collagen type I (TAMRA-labeled, red); F-actin (phalloidin, green), DNA (DAPI, blue). Top view, maximal projection of 343 μm. Scale bar, 150 μm. Insets, higher magnification of one crypt containing an organoid. Single plane (i), maximal projection of 152 μm (ii). Scale bar, 20 μm. B. Organoids expressing LifeAct-GFP (F-actin label) spreading over collagen scaffolds. Time in hours. Top view. The dashed line outlines the base of the villus. Scale bar, 200 μm.