Figure 6.

The co-culture of the fecal microbiome in a PMI Chip lined by 3D intestinal epithelium under an AOI. (A) The overlaid images of a DIC and a fluorescent micrograph show the snapshot of a host–microbiome co-culture in the PMI Chip. The human fecal microbiome (initial seeding density, 5 × 10⁴ cells/mL) was co-cultured with the germ-free Caco-2 intestinal epithelium in a PMI Chip under luminal flow (100 µL/h) and multiaxial stretching motions (5% in cell strain, 0.15 Hz in frequency) for 2 days. The AOI was pre-established by perfusing an antibiotic-free anoxic and oxic culture medium in the upper and lower microchannel, respectively for 12 h. The fecal bacteria that formed microcolonies were visualized using Live/Dead staining dye in the lumen microchannel. We performed the same staining into the germ-free PMI Chip (Control). An inset in the “Co-culture” shows the viability of the isolated human fecal microbiome acquired by confocal microscopy. (B) The epithelial barrier function was maintained (> 3 kΩ·cm²) regardless of the AOI or the co-culture with the fecal microbiome. The barrier function was assessed by normalizing TEER values. Bar, 50 µm. NS, not significant.