A Bionic Colon Model Equipped with Microbial Ecology via Facilitating Formation of Bacterial Biofilm

Current in vitro colon models predominantly employ planktonic fecal bacterial fermentation. We designed a colonic microbial culture model consisting of bionic mucus, mucosa and muscularis. The bionic mucus contained bacterial quorum sensing molecule, autoinducer-2 (AI-2), for stimulating biofilm formation. The bionic mucosa was a UV-curable 15% GelMA/1% HAMA/0.5% PVAMA composite hydrogel, serving as a biocompatible biofilm attachment interface. The bionic muscularis made of silicone was designed as a physical barrier isolating the anaerobic microbial ecosystem and external environment. The experiment of culturing infant feces showed that this culture model can construct a microbial microecosystem that enables microorganisms to attach. Confocal laser scanning microscopy and scanning electron microscopy demonstrated bacterial colonization attached within the hydrogel pores. Quantitative PCR revealed that biofilm-associated bacterial abundance could reach 7.56 × 108 gene copies/g, which was approximately two orders of magnitude higher than that in the mucus. AI-2 further modulated microbial community assembly by promoting the enrichment of Bifidobacterium, increasing its abundance from 9.20 × 107 to 1.77 × 108 gene copies/g, while suppressing Escherichia-Shigella from 2.98 × 108 to 2.00 × 108 gene copies/g after 24 h cultivation. This study aimed to construct a bionic colon model that supports the colonization of fecal microbiota for survival, growth, attachment and community succession. Serving as a microbial culture bioreactor, this model provided a physiologically relevant in vitro platform to investigate the characteristics of colonic biofilm-associated microbial ecology and corresponding microbiota intervention strategies.