Scientists have created an innovative bacterial sensor that may offer a noninvasive alternative to colonoscopies. Reported in ACS Sensors, the new technology uses microscopic spheres packed with blood-sensing bacteria that detect gastrointestinal disease markers. These orally administered “pills” also contain magnetic particles, making them easy to retrieve from stool.
A New Way to Detect Gastrointestinal Bleeding
Once excreted by mouse models with colitis, the microsphere sensor detected gastrointestinal bleeding within minutes. According to co-author Ying Zhou, this platform introduces “a new paradigm for rapid and noninvasive detection of gastrointestinal diseases.” The researchers believe these bacteria can be adapted to identify other gut-related conditions.
Why Colonoscopies Have Limitations
Millions in the U.S. live with colorectal cancer or inflammatory bowel disease, including colitis. While colonoscopy remains the gold-standard diagnostic tool, many people avoid it due to the required preparation and its invasive nature. To overcome these barriers, Zhou, Bang-Ce Ye, Zhen-Ping Zou, and colleagues are designing gentler tools that detect disease biomarkers such as heme, an indicator of intestinal bleeding.
How the Microsphere Sensor Works
As reported by medicalxpress, the team had earlier engineered heme-sensing bacteria that emit light when exposed to blood. However, these bacteria degraded inside the digestive tract and were difficult to collect. In this study, the researchers encapsulated the glowing bacteria and magnetic particles inside sodium alginate hydrogels—creating tiny, durable microspheres. These hydrogels protect the bacteria from digestive fluids while still allowing heme to trigger the light signal.
Testing the Technology in Mouse Models
Researchers orally administered the microspheres to mouse models exhibiting varying degrees of colitis. After the sensors passed through the digestive system, they retrieved them using a magnet. The results showed that:
- Collecting microspheres and analyzing signals took only 25 minutes.
• Light intensity increased with worsening disease severity, indicating higher heme levels.
• Healthy mice tolerated the microspheres well, confirming biocompatibility.
Potential for Future Human Use
Although human trials are still pending, the team notes that this encapsulation method could enable fast, noninvasive diagnosis of gastrointestinal diseases. Moreover, it may help track treatment response and monitor disease progression over time.