Nanospatially confined ROS eliminator produced in situ by engineered Escherichia coli Nissle 1917 for oral treatment of inflammatory bowel disease.

Oral interventions using engineered bacteria are effective for preventing and treating digestive diseases, yet improving bioavailability remains challenging. This study constructed a probiotic pharmaceutical factory using the probiotic Escherichia coli Nissle 1917 (EcN) as the chassis to deliver antioxidant enzymes via in situ oral administration. Engineered bacteria continuously produced nanobiotic reactors by hijacking the endogenous production line of bacterial outer membrane vesicles (OMVs). Protein turnover and outer membrane oxidative stress were used to increase outer membrane instability while promoting OMV generation. The engineered bacteria maintained high antioxidant enzyme expression even in the hypoxic colonic environment, ensuring therapeutic efficacy post-oral administration. Meanwhile, the SpyCatcher/SpyTag self-anchored system enabled targeted encapsulation of protein drugs into OMVs, enhancing programmability and precision. In a dextran sulfate sodium (DSS)-induced ulcerative colitis mouse model, the engineered bacterial factory was shown to reduce inflammation, repair the intestinal epithelial barrier, and regulate gut microbiota. This OMV-targeted encapsulation only requires replacing therapeutic proteins and adding SpyTag to customize factories for different needs, highlighting its potential in clinical digestive disease treatment.