A New 3D Colon on a Chip to Decipher the Influence of Mechanical Forces on the Physiological Cellular Ecosystem.

The gut epithelium ensures nutrient absorption and barrier protection, functions tightly linked to its 3D architecture and dynamic mechanical activity. To dissect how mechanical forces influence intestinal physiology, we developed a stretchable 3D colon-on-chip that integrates tunable topography, stiffness and peristalsis-like motion within a physiologically relevant microenvironment. The model employs 3D scaffolds composed of either pure collagen I or mechanically reinforced interpenetrated network (IPN) made of collagen I and PEGDA. Tensile tests mimicking peristalsis revealed that both hydrogels soften upon stretching, with the IPN maintaining higher stiffness than pure collagen. Using this platform, we applied cyclic stretching for 24 to 72 h to co-cultures of stromal and epithelial cells, and systematically assessed the contributions of stiffness, curvature and shear stress. We found that the stretching was a dominant factor governing epithelial behavior, markedly enhancing proliferation and apicobasal polarization without altering differentiation. Altogether, this work introduces a next-generation colon-on-chip that unites mechanical control and biological complexity, providing a powerful tool to unravel how physical cues orchestrate intestinal homeostasis and paving the way for modeling disease states such as colorectal cancer and inflammation.