Once swallowed, this capsule is designed to collect bacteria throughout the...
Once swallowed, this capsule is designed to collect bacteria throughout the gut. A scientist unscrews the cap to retrieve the sample after the capsule has left the digestive system.
Source: Purdue University photo/Mark Simons

A bacteria-grabbing smart capsule

Researchers at Purdue University have developed a 3D printed ingestable capsule that can capture samples throughout the gut and safely transport these outside the body for testing.

Your gut bacteria could say a lot about you, such as why you're diabetic or how you respond to certain drugs. But scientists can see only so much of the gastrointestinal tract to study the role of gut bacteria in your health. What comes out of you is just a small sample of these bacteria, without indicating where they came from in the digestive system.

Purdue University researchers built a way to swallow a tool that acts like a colonoscopy, except that instead of looking at the colon with a camera, the technology takes samples of bacteria. The technology could also move throughout the whole GI tract, not just the colon. This tract, in addition to the colon, includes the mouth, esophagus, stomach, pancreas, liver, gallbladder, small intestine and rectum. Essentially, this tool would make it possible to conduct a "gut-oscopy." 

"It's all about being able to take samples of bacteria anywhere in the gut. That was impossible before," said Rahim Rahimi, a Purdue assistant professor of materials engineering.

The tool is a drug-like capsule that passively weasels through the gut without needing a battery. A pill version of a colonoscopy is already commercially available to view areas of the colon that a traditional colonoscopy can't see, but neither tool can sample bacteria. "If a colonoscopy or camera pill sees blood, it can't sample that area to investigate further. You could just sample bacteria from a person's fecal matter, but bacteria can vary a lot throughout the GI tract. Our approach could be complementary," Rahimi said.

The bacteria-sampling capsule also would be a lot cheaper, each costing only about a dollar, he estimates. Rahimi's team is working on testing this capsule in pigs, which have a similar GI tract to humans. The researchers 3D-printed the capsule out of resin, the same material used in dental molds and implants. This material would need to be slightly modified for humans to ingest, but is otherwise nontoxic, Rahimi said.

When exposed to the pH of a certain gut location, the capsule's biodegradable cap dissolves. Inside the capsule, a hydrogel similar to those used in diapers expands and collects intestinal fluid containing bacteria. Pressure closes shut the capsule's aperture when the sampling is complete, kind of like a plunger.

The researchers have tested the prototype capsule in a culture solution designed to simulate the gut bacterial flora of a GI tract. They also tested the capsule's ability to protect the sampled bacteria in different extreme environments. Their experiments so far show that the capsule could successfully sample bacteria common in the gut, such as E. coli, within an hour.

In a human, the capsule would continue to move throughout the GI tract with other fecal matter. A scientist could then recover the capsule from a study participant's fecal matter, unscrew the capsule, and study the collected bacteria. "This approach is providing new opportunities to study what type of bacteria are present in the gut. It would help us figure out how to manipulate these bacteria to combat disease," Rahimi said.

An initial demonstration of the prototype is published in RSC Advances.

Subscribe to our newsletter

Related articles

Researchers create 3D-printed nasal swab for COVID-19 testing

Researchers create 3D-printed nasal swab for COVID-19 testing

Results of the first clinical trial of 3D printed NP swabs for COVID-19 testing are being presented at the annual meeting RSNA.

Using bacteria as micro-3D printers

Using bacteria as micro-3D printers

Researchers have used bacteria to produce intricately designed three-dimensional objects made of nanocellulose.

3D printed micro-scale fluid channels

3D printed micro-scale fluid channels

Researchers have 3D printed unique fluid channels at the micron scale that could automate production of diagnostics, sensors, and assays used for a variety of medical tests and other applications.

3D printed smart swabs for COVID-19 testing

3D printed smart swabs for COVID-19 testing

Researchers have created a 3D printed self-adjusting smart swab that could be used for COVID-19 testing.

'Smart' breathalizer can reveal lung disease

'Smart' breathalizer can reveal lung disease

Using specialized nanoparticles, engineers have developed a way to monitor pneumonia or other lung diseases by analyzing the breath exhaled by the patient.

Custom-designed swabs for diagnosis of SARS-CoV-2

Custom-designed swabs for diagnosis of SARS-CoV-2

Researchers have developed a total of three swab designs that are comparable to the current ‘gold standard’ swabs.

The next-gen 'smart pill' for cancer detection

The next-gen 'smart pill' for cancer detection

Researchers are developing a pill-sized capsule that uses AI-enabled sensing to diagnose gastrointestinal cancers and bleeding earlier.

A novel swab design to augment COVID-19 testing

A novel swab design to augment COVID-19 testing

Scientists have developed a novel test swab that can be 3D printed using inexpensive, widely available materials and speedily assembled in a range of fabrication settings.

Smart contact lenses diagnose and treat diabetes

Smart contact lenses diagnose and treat diabetes

Researchers developed wirelessly driven ‘smart contact lens’ technology that can detect diabetes and further treat diabetic retinopathy just by wearing them.

Popular articles