Bioinspired Anti-digestive Hydrogels Selected by a Simulated Gut Microfluidic Chip for Closing Gastrointestinal Fistula

The anti-digestive features given to hydrogels can prolong their action time in gut environment; however, these types of hydrogels have rarely been reported. Inspired by indigestibility of dietary fibers, we introduced an injectable covalent hydrogel through photopolymerization of glycidyl methacrylate-modified xanthan. This newly synthesized hydrogel exhibited a specific concentration-dependent porosity, swelling ratio, and stiffness. The intestinal epithelial cells-6 could grow on the surface of the stiffer hydrogel, and achieved their gut barrier functions. A simulated gut microfluidic chip was manufactured to demonstrate the hydrogel's good performance of anti-digestion compared with the current product, fibrin sealant. Furthermore, calcium ions could induce the swelling-shrinking behavior of the hydrogel, which assisted in removing the hydrogels at the proper time so as to avoid the mismatch of hydrogel degradation and tissue regeneration. Therefore, this hydrogel is expected to be an outstanding gut repair material, especially for closing gastrointestinal fistula.