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Scientists test ingestible device that measures metabolism

The gut monitor being tested at UC San Diego is 2.5 centimeters long and has been tested in pigs. Undated photo.
UCSD Jacobs School of Engineering
Undated photo of the gut monitor being tested at UC San Diego is 2.5 centimeters long and has been tested in pigs.

It’s an electronic monitor, the size of an oblong pill, that is swallowed and ends up in your gut. There, it can track sugar levels until, a day or two later, it comes out the other end.

UC San Diego engineering professor Patrick Mercier led the discovery team. Mercier said the experimental device — tested in pigs — can chemically probe a part of you that’s difficult to reach.

Mercier said what goes on in the gut can only be tested with stool samples or by forcing a tube down your throat. He says an ingestible monitor can be faster and easier.


“It goes into your stomach … into your (gastrointestinal) tract. And it’s a wireless device so you can get real time information of what’s going on in the dynamical environment inside your gut and read it out on your phone” Mercier said.

There's an inherent risk swallowing a battery. So they had to find another way to make it work. The answer turned out to be glucose.

“We are monitoring sugars — glucose,” he said. “And the device itself is powered by a fuel cell that harvests energy from those same sugars that we’re measuring.”

Mercier said the monitor can be designed to also test acidity levels in the gut that cause upset stomachs.

Mercier is the co-director of UCSD’s Center for Wearable Sensors. He expects people will ultimately track their test results with an app, similar to wearable devices that measures heart rate and stress levels.


“We do like this idea of democratizing healthcare and putting devices in the hands of patients,” he said. “That is a future of healthcare that we’re very excited about.”

Mercier adds that people may want a doctor to help interpret their test results. He hopes they will be able to test the device in humans in a couple of years.