Jalili-Firoozinezhad, S. et al. Nat. Biomed. Eng. https://doi.org/10.1038/s41551-019-0397-0 (2019).

Recent studies of human gut microbes and their interactions with hosts have uncovered their key roles in human health and disease. These studies have relied mainly on metagenomic analysis of in vivo samples. In vitro models that mimic the complex gut environment are still needed. Jalili-Firoozinezhad et al. introduced an intestine-on-a-chip that integrates intestinal endothelium, epithelium, a mucus layer, and gut microorganisms, as well as two microscale oxygen sensors, into a microfluidic organ-chip device. The integration of oxygen sensors allows in situ measurement and control of oxygen levels, thus creating a physiologically relevant oxygen gradient across the endothelium–epithelium–microbiome interface. The hypoxic intestine-on-a-chip supports more bacterial diversity than aerobic chips or conventional liquid culture, and thus better reflects the abundance pattern of human intestinal microbiota. Ultimately, researchers aim to offer patient-, disease-, or organ-specific host-microbiome models for personalized medicine.