Biomimicking corals: Smart capsules sample gut bacteria that conventional tests miss

Researchers have created an ingestible pill that can sample bacteria from the small intestine to help advance understanding of the gut microbiome. The team says the invention provides a more comprehensive picture of this bacterial landscape than conventional stool samples.

The capsule’s surface is inspired by the intricate, porous structures of marine corals, which shelter diverse microbial communities. The project leaders from New York University (NYU), US, and NYU Abu Dhabi, UAE, say it is the first passive, non-invasive way to collect microbes from the upper digestive tract. 

Once swallowed, the Cellularly Organized Repeating Lattice (CORAL) capsule physically traps bacteria as it travels through the digestive system before exiting the body. 

The researchers explain that the small intestine plays a crucial role in host-microbiome interaction as it contains a high density of receptors, immune cells, and neurons. However, analysis with stool samples, the current gold standard for microbiome research, primarily reflects bacteria from the large intestine. 

Co-senior author Aashish Jha, assistant professor of Biology at NYU Abu Dhabi, says the smart capsule addresses a “significant blind spot” in microbiome science by capturing these inaccessible bacteria. 

“Understanding these upstream microbial communities could be key to early disease detection and developing more targeted therapeutic interventions.”

Trapping bacteria

The capsule uses mathematically defined structures called Triply Periodic Minimal Surfaces to mimic marine corals. These structures create a maze-like network of channels with pore sizes optimized to trap bacteria but can pass safely through the digestive tract. 

According to the researchers, the CORAL capsule could be scaled for widespread use. It is produced using a single 3D printing step and doesn’t contain moving parts. In contrast, existing microbiome sampling devices often rely on magnets, mechanical actuators, or electronic components.

The capsule’s surface is inspired by the intricate, porous structures of marine corals, which shelter diverse microbial communities.The device only begins sampling when it reaches the small intestine due to a special coating. 

“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,” explains Hanan Mohammed, lead author of the study and research associate at NYUAD. “It gives us access to bacterial communities that have been invisible to researchers until now.”

The researchers validated CORAL in animal studies, where the device captured distinct bacterial populations from the small intestine that differed significantly from fecal samples. 

For example, the samples contained higher levels of beneficial bacteria like Lactobacillus, which thrive in the upper gut’s lower pH environment, but miss bacteria typically found in the large intestine.

Sampling the small intestine

The gut microbiome has been linked to various health benefits, such as immunity and mental health. 

The study authors explain that the small intestine’s microbial populations play essential roles in metabolism and immunity that differ significantly from those in the colon. However, most stool-sample studies miss the microbial communities of the small intestine. 

The researchers say CORAL could be scaled for widespread use as it is produced in 3D printing and doesn’t contain moving parts.“Fecal samples, though easy to collect, do not accurately represent the microbial communities in distinct regions of the gut,” says study author Khalil Ramadi. He is an assistant professor of bioengineering at NYU Tandon School of Engineering, US, and director of NYU Abu Dhabi’s Laboratory for Advanced Neuroengineering and Translational Medicine. 

The work, published in Device, represents Ramadi’s mission to develop “electroceuticals” — ingestible electricals instead of drugs — to diagnose and treat conditions such as immune disorders and metabolic diseases by leveraging the body’s natural neural pathways. 

Human health applications

Although the researchers only tested CORAL in rodent models, they envision translating it to human use in the future. This would involve scaling the capsule from its current dimensions, fit for rats, to a standard pill size. 

However, before starting with human trials, the team says it would need to develop reliable retrieval methods, such as magnetic detection or other identification techniques. In addition, it would need to conduct extensive safety testing to ensure that CORAL poses no risk to patients. 

The team is continuing this work in the lab and actively working to commercialize this technology through the Abu Dhabi Department of Health and the HealthX program at StartAD, a global accelerator that supports technology start-ups in launching, developing, and scaling their ventures.