Fig. 1: Establishment and characterization of the co-culture of colonic epithelium, dendritic cells, and macrophages in the GuMI system.

a Workflow of colonic epithelial monolayer generation (green line), monocyte isolation, and differentiation to antigen-presenting cells (APCs, i.e., dendritic cells and macrophages; orange line), GuMI hardware preparation (aqua line), GuMI device assembly, operation, and sampling (merged lines). Circles in the metro map indicate the critical tasks and the workload. b Illustration of designed co-culture of primary colonic epithelium with APCs in GuMI (GuMI-APC). c–f Brightfield images of colonic epithelial monolayer, dendritic cells, macrophages, and co-culture. c Colonic epithelium without APCs in GuMI. Green arrows indicate the clear cell border among the epithelial cells. d Dendritic cells and e macrophages before adhering to the bottom of the semi-permeable membrane in the transwell insert with pore size of 0.4 μm. Orange arrows indicate the dendrite and phagosome-like structures in d, e. Green arrows in c indicates the border of epithelial cells. Green and yellow arrows in f indicates the shading of immune cells underneath the epithelium. Scale bars in c–f: 300 µm. g Transepithelial electrical resistance (TEER) values of the monolayer in GuMI-APC (orange bar) and GuMI (black bar) after 72 h in GuMI. The error bar indicates the standard deviation. n = 3. ns: not significant, two-tailed unpaired t test.