3D-printed capsule could collect bacteria from throughout the gastrointestinal tract

Written by Georgi Makin

3D-printed capsule
CREDIT: Purdue University photo/Mark Simons

A novel 3D-printed capsule, developed by a team at Purdue University (IL, USA), could allow for the collection of bacteria samples from throughout the gastrointestinal tract, improving on conventional sampling methods that may exclude areas for bacteria collection outside of the colon.

With an approach described as being similar to a colonoscopy – without the imaging – the 3D-printed capsule could collect samples from areas including the mouth, esophagus, stomach, pancreas, liver, gallbladder, small intestine and rectum, potentially enabling what the researchers have referred to as a ‘gut-oscopy’.

“It’s all about being able to take samples of bacteria anywhere in the gut. That was impossible before,” explained Rahim Rahimi, Assistant Professor of materials engineering at Purdue University.

In a 3D-printed capsule that resembles a conventional drug, the device can move through the gut naturally without the need for complex mechanics or battery power. While a similar device exists to carry a camera throughout the colon to collect images in a similar way to a colonoscopy, it has not yet been possible to collect bacteria samples.

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“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 added.

Costing around US$1 to produce, the 3D-printed capsule has been printed from a resin used by dentists in the development of molds and implants. While it may need to be modified or adjusted for human ingestion, the capsule has so far been successful when tested in the gastrointestinal tracts of pigs, with initial results outlined in RSC Advances.

The collection mechanism involves a biodegradable cap dissolving when exposed to the pH of the desired location. Once the cap has dissolved, a hydrogel collects intestinal fluid and bacteria and pressure closes the capsule once the hydrogel has expanded. A scientist can then examine the capsule once expelled with fecal matter, unscrewing the cap to retrieve the sample for analysis.

“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 concluded.

Sources: Waimin JF, Najati S, Jiang H, Qiu J, Wang J, Verma MS, Rahimi R. Smart capsule for non-invasive sampling and studying of the gastrointestinal microbiome. RSC Advances. 10(28), 16313–16322 (2020); www.purdue.edu/newsroom/releases/2020/Q3/swallowing-this-colonoscopy-like-bacteria-grabber-could-reveal-secrets-about-your-health.html

Feature image: 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. Credit: Purdue University photo/Mark Simons