A radically simple, ingestible colorimetric biosensor pill for cost-effective, non-invasive monitoring of intestinal inflammation

Inflammatory bowel diseases (IBDs) affect millions worldwide, necessitating frequent monitoring of intestinal inflammation to optimize treatment strategies. However, current fecal calprotectin tests have low patient adherence, limiting their utility for inflammation monitoring. Here, we developed an ingestible biosensor for simplified at-home detection of a key inflammation biomarker-reactive oxygen species (ROS). Our pill for ROS-responsive inflammation monitoring (PRIM) employs an ROS-responsive polymer that selectively degrades in the presence of ROS. Degradation triggers the release of blue dye into feces for a visually detectable readout without fecal sampling or laboratory analysis. <i>In vitro</i>, PRIM remained stable under healthy conditions and activated only at elevated ROS levels (10-50 mM H₂O₂). In rats with colitis, the miniaturized PRIM demonstrated a sensitivity of 78% and a specificity of 72% in detecting intestinal inflammation. With further optimization, PRIM has the potential to improve accessibility and patient adherence to inflammation monitoring and enhance personalized disease management for IBD.