Gastrointestinal Self-Adaptive and Nutrient Self-Sufficient -Gelatin Porous Microgels for Synergistic Therapy of Ulcerative Colitis.

To realize effective and long-term synergistic therapy of ulcerative colitis (UC) with probiotics, we developed gastrointestinal self-adaptive and nutrient self-sufficient (AKK)-gelatin porous microgels (AKK@GPMGs). In AKK@GPMGs, AKK was covered with sequential layers of proanthocyanidins (PAs), mucin (MUC), and phosphatidylcholine (PC) to obtain AKK@PAs-MUC-PC (AKK@PMP), and then encapsulated within the methacrylate-modified gelatin porous microgels. AKK@GPMGs provide sufficient mucus as a nutrition source for AKK and boost resistance to stomach acid by 30.49-fold, and colonization in the intestines is enhanced by 83.46 times. The microgels can be dissociated by matrix metalloproteinase at the inflammatory sites of the intestine, and release AKK@PMP, which acts as "band-aid" that adheres to the inflamed colon for a long time and offers improved synergistic therapy for UC. Compared to uncoated AKK, AKK@GPMGs increase reactive oxygen species scavenging capacity by 26.47 times, improve the intestinal mucus layer thickness by 5.63 times, increase the goblet cells abundance by 3.93 times, reduce intestinal permeability by 5.60 times and significantly enhance beneficial gut microbiota while repressing harmful microbiota. These results indicate that AKK@GPMGs can restore mucus layer and tight junction integrity, reduce inflammation and oxidative stress, and regulate gut microbiota homeostasis to effectively treat intestinal inflammation.