The human microbiome consists of more than 1000 different bacterial species that play essential roles in growth and differentiation of the healthy GI-tract, protection against pathogens, and resistance to cancer.  Dysbiosis in the gut has been linked to several conditions including diabetes, colorectal cancer and multiple sclerosis. Previous research has focused more on understanding how the bacterial imbalance impacts on disease, yet the way commensal bacteria influence normal development at a cellular level remains largely elusive. This study aims to develop a physiologically-relevant gastrointestinal human–microbiome interface in a dynamic flow bioreactor by co-culturing Caco-2 and HT29-MTX cells with commensal bacterial strains.

The bioreactor emulates the in vivo peristaltic flow, continuously supplying nutrients and oxygen to the apical and basal sides of the membrane. It was found that the addition of laminar flow better recapitulates the physiological events that occur in healthy GI-tract and may yield more accurate results in vitro. The results show that the dual-flow bioreactor can increase cell viability over time when the flow applied is 150 µl/min or below.  This model may reveal new insights into host–microbe molecular interactions and has high potential for breakthroughs in the development of a physiologically realistic GI-tract model.