A Dynamic Gastrointestinal Mucus Simulator for Biorelevant Assessment of Nutrient Mucopenetration: Effects of Mucus Purification, Calcium, and Soluble Fibers

Gastrointestinal mucus is the first barrier encountered by luminal nutrients, but conventional static models do not reproduce mucus deformation under dynamic luminal flow. Additionally, the effects of mucus purification and dietary components on mucus barrier function remain insufficiently characterized. To address these gaps, a dynamic gastrointestinal mucus simulator was developed to evaluate mucus permeability under continuous luminal flow and investigate the effects of mucus purification and dietary components. The results showed that the dynamic model produced an approximately twofold glucose permeability compared with the static model, while increasing luminal flow further enhanced glucose permeability. Phycocyanin exhibited approximately 10-fold lower permeability than glucose, demonstrating the sensitivity of the model to differences in molecular properties. Additionally, mucus purification may compromise its barrier function due to the loss of gel-forming components. Dietary calcium and fibers enhanced the mucus barrier through different mechanisms, with 10 mM calcium reducing phycocyanin permeability by approximately 42%, and 6% cellulose nanocrystals and 2% alginate reducing glucose permeability by approximately 79% and 37%, respectively, suggesting their potential for modulating nutrient mucopenetration. This study provides an effective tool for evaluating mucus permeability and highlights the mucus barrier as an underexplored pathway where dietary components may modulate nutrient mucopenetration.