Crypt-substrate interaction. (A) Representative time-lapse images of monolayer formation on the experimental substrates from crypts isolated from a Sox9 eGFP-CAGDsRed mouse. eGFP and DsRed fluorescence was overlaid on brightfield microscopy images. Upon adherence to glass, oxidized polystyrene and epoxy photoresist, crypt-cells rapidly differentiate. (B) Quantification of the percentage of crypts forming a monolayer when crypts were cultured on the microfabrication substrates over 1 week. (C, D) Whole-mount immunohistochemical staining of a monolayer after 1 week in culture. Fluorescence images are shown for: mucin-2 (green, C) and chromogranin-A (green, D). (E) Fluorescence image after an 8-hour EdU pulse (red). Hoescht 33442 was used as a nuclear stain (blue) in panels C-E. Scale bars = 50 μm.