Figure 2. Organoid Systems.

(a) Schematic cross-section through an intestinal organoid. Stem cells (green) are enriched in buds, and differentiated cells (red) are enriched along the luminal aspect. (b) Organoids cultured within Matrigel. The top panel is a schematic of a patty with 5 organoids. The lower panel is a fluorescence image of four different organoids demonstrating that tumor necrosis factor α (TNF-α) decreases EdU incorporation or cell proliferation. Scale bars: 50 μm. Adapted with permission from [42]. (c) Organoids cultured within a microwell. The top panel is a schematic of a side view of a single organoid within a microwell on a microdevice. The lower panel is the top view of an overlaid fluorescence and brightfield image before and after microinjection of two organoids in microwells. The top organoid was successfully injected with a green fluorophore while the lower organoid was not. Scale bars: 200 μm. Reproduced from with permission from [38]. (d) Organoids on a Matrigel surface. The top panel is side-view schematic of 3 organoids on Matrigel. The lower panel is a top view image of two organoids before and after application of forskolin or a DMSO control. Red coloring indicates organoid size prior to stimulus addition while cyan indicates the organoid size after the stimuli. Scale bars: 150 μm. Adapted with permission from [39].