Magnetic Hydrogel: Enhanced Bacterial Biosensor for Speedy Gut Disease Detection

Bacterial biosensors represent a promising avenue for detecting gastrointestinal disease biomarkers; however, their direct oral delivery is limited by challenges such as bioavailability, safety, and interactions with the complex gut microbiota. To address these issues, we developed MagGel-BS, a Magnetic hydroGel-encapsulated Bacterial bioSensor platform. This hybrid system combines biocompatible alginate hydrogel to encapsulate both magnetic particles and bacterial biosensors, facilitating precise detection of disease biomarkers. The hydrogel significantly enhances stability, improving bacterial viability in gastric fluid by 10-fold. Utilizing heme-responsive bacteria, MagGel-BS was able to detect gastrointestinal bleeding in mice within only 20 min, a significant improvement compared to unencapsulated biosensors, which took several hours. Importantly, MagGel-BS showed no immune responses or adverse effects in vivo. In summary, this platform provides a rapid, noninvasive approach for gastrointestinal biomarker detection, demonstrating considerable potential for advancing bacterial-based diagnostics and therapeutics applications.