Polymer-Induced Restructuring in the Gut

The gut governs digestion and nutrient absorption, is a promising target for drug delivery, and teems with micro-organisms that can have remarkably strong effects on host health. Despite its importance, however, little is known about how the structure and function of the gut are influenced by many of the materials that transit through it regularly. By combining experiments on mice, biophysical processing and characterization, and microscopy, we show how polymers abundant in the gut — such as secreted mucins, dietary fibers, or administered therapeutics — can alter the structure of the gut and its contents. We compare our results to the predictions of a simple thermodynamic model, showing how aspects of this complex behavior can be understood in the framework of polymer solution theory. Our results provide a foundation for disentangling the interactions between polymers and the gut; more broadly, our work highlights how physical principles can be used to understand and possibly control how polymers regulate structures in the body.