Researchers have built a magnetically controlled capsule that samples the small intestine. The work was published in the journal Device in 2026. Here is how it works.

The capsule has a brush-like structure. A doctor guides it with external magnets. As it moves through the small intestine, the brush collects samples from the gut lining. This gives scientists material to study the microbiome, the community of microbes living inside us.

Current methods for sampling the small intestine are limited. Endoscopes cannot easily reach deep into it. Surgery is invasive. A steerable capsule could collect samples without an operation.

The technology is still preclinical, meaning it has not been tested in humans yet. Challenges remain. The capsule must be small enough to swallow. Magnets must work over a useful distance. If these are solved, doctors could one day study gut diseases with a simple swallowable device. The small intestine plays a big role in digestion and immunity. Its microbes affect health in ways scientists are still discovering. Better sampling could improve diagnosis of gut disorders. The research team is led by Yuguo Dai and colleagues. Their paper appears in Device with the DOI 10.1016/j.device.2026.101304.