Suspended Collagen Hydrogels to Replicate Human Colonic Epithelial Cell Interactions with Immune Cells

Abstract The human colon plays a critical role in fluid and salt absorption and harbors the largest immune compartment. There is a widespread need for in vitro models of human colon physiology with its innate immune system. A method is described to produce a cassette with a network of struts supporting a suspended, non‐chemically cross‐linked collagen hydrogel scaffold compatible with the co‐culture of primary gastrointestinal epithelium and migratory inflammatory cells. The epithelial monolayer cultured on the suspended collagen possesses a population of polarized and differentiated cells similar to that present in vivo. This epithelial layer displays proper barrier function with a transepithelial electrical resistance (TEER) ≥ 1,500 Ω cm 2 and an apparent permeability ≤10 −5 cm 2 s −1 . Immune cells plated on the basal face of the scaffold transmigrated over a period of 24 h to the epithelial layer in response to epithelial production of IL‐8 induced by luminal stimulation of Clostridium difficile Toxin A. These studies demonstrate that this in vitro platform possesses a functional primary colonic epithelial layer with an immune cell compartment capable of recruitment in response to pro‐inflammatory cues coming from the epithelium.