Extended Data Fig. 5. Evidence that monolayers generated from preterm intestinal-derived organoids are differentiated and entirely cover the transwell.

a, Three technical replicates (R1, R2, R3) of alcian blue stained organoid monolayers on transwell inserts. Goblet cells and mucus layer are stained blue indicating the cells have differentiated and the goblet cells are secreting mucus apically. This further demonstrates that the monolayers are polarised and entirely cover the transwell. b, Scanning electron microscopy image at different magnifications showing microvilli resulting from enterocyte differentiation and that cells are contiguous (that is, no holes in monolayer). c, We performed regular visual inspection of the monolayers using light microscopy, and for all monolayers used in this experiment the monolayers showed full confluence across the entirety of the transwell insert.