Coral-Inspired Capsule Samples Hidden Bacteria from Small Intestine

The gut microbiome has been linked to conditions ranging from immune disorders to mental health, yet conventional stool tests often fail to capture bacterial populations in the small intestine. This region, the body’s largest mucosal surface, is crucial for host-microbiome interactions, metabolism, and immunity, but remains difficult to access. Researchers have now developed a swallowable capsule that passively collects microbes from the upper digestive tract, offering a clearer view of hidden bacterial communities missed by conventional stool tests.

The device, called the CORAL (Cellularly Organized Repeating Lattice) capsule, was developed by researchers from NYU Tandon School of Engineering (Brooklyn, NY, USA) in collaboration with NYU Abu Dhabi (Abu Dhabi, UAE). Inspired by the porous structures of marine corals, it is fabricated in a single 3D printing step and contains no moving parts, electronics, or magnets. Its design is based on mathematically defined Triply Periodic Minimal Surfaces (TPMS), forming a maze-like lattice that traps bacteria while allowing safe passage through the digestive tract.

Image: Conceptual design of the CORAL capsule for microbial sampling in the small intestine (H. Mohammed et al., Device (2025). DOI: 10.1016/j.device.2025.100904)

A special coating ensures the capsule only begins sampling once it reaches the small intestine, preventing contamination from stomach acid. In animal studies, the capsule successfully captured distinct microbial populations that differed significantly from fecal samples. The findings, published in Device, showed higher levels of beneficial bacteria such as Lactobacillus, demonstrating that the capsule can reveal microbial communities missed by conventional methods.

The capsule’s simplicity and scalability make it a promising tool for microbiome research and clinical diagnostics. Unlike existing devices, it provides a non-invasive, passive method to map microbial ecosystems in situ. Researchers plan to scale the capsule to pill size, develop reliable retrieval methods, and conduct safety testing ahead of human trials.

"We designed CORAL to be as simple as possible, no batteries or electronics, just a mathematically precise structure that uses the gut's natural movement to sample bacteria," said Hanan Mohammed, lead author of the study. "It gives us access to bacterial communities that have been invisible to researchers until now."

Related Links:
NYU Tandon School of Engineering
NYU Abu Dhabi