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

## TL;DR

A new ingestible pill detects intestinal inflammation by changing the color of feces, offering a simple and non-invasive way to monitor gut health at home.

## Contribution

The PRIM pill introduces a novel ROS-responsive polymer that triggers dye release in the presence of intestinal inflammation without requiring fecal sampling.

## Key findings

- PRIM remained stable under healthy conditions and activated at elevated ROS levels (10–50 mM H2O2) in vitro.
- In rats with colitis, PRIM demonstrated 78% sensitivity and 72% specificity for detecting intestinal inflammation.

## Abstract

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. In vitro, 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.

This study describes the development of an ingestible pill-based biosensor device, the pill for reactive oxygen species (ROS)-responsive inflammation monitoring (PRIM), that uses ROS-responsive polymers to trigger colored dye release in the presence of intestinal inflammation. Proof of concept is supported by consistent observation of blue feces in rats with colitis. The PRIM device’s simple dye release mechanism would eliminate fecal sample handling and analysis and is a promising candidate for a patient-friendly, cost-effective solution for intestinal inflammation monitoring.