Researchers at MIT and Brigham and Women's Hospital have developed a proof-of-concept flexible sensor that can be ingested, attaches to the inside of the stomach lining, and collects and transmits data on stomach movement and meal ingestion. The device is piezoelectric, which means it can be powered by the mechanical energy generated by the stomach, allowing it to last for at least two days without an internal or external battery. The research was published today in Nature Biomedical Engineering.

"Just as a wearable device like a Fitbit can help track and quantify how many steps a person takes, we envision a device that could reside in the stomach and quantify how frequently a person is eating," Dr. Carlo "Gio" Traverso, a gastroenterologist and biomedical engineer at Brigham and Women's, said in a statement.

The device isn't just a tiny sensor embedded in a pill, like Proteus Digital Health's ingestible sensor. It's a flexible sensor that can be folded up into a pill. After it gets into the stomach through oral ingestion it unfolds, settles on the stomach lining, and then measures the movement of stomach walls, which can return data about when a person is eating or drinking as well as when and how they're moving.

In the study the sensor was not tested in humans. Instead it was evaluated first in an artificial environment, then in a recently removed pig's stomach, and finally in sedated and ambulatory pigs. The research device didn't include any wireless communication capabilities to transmit the readings, but researchers monitored the electrical output of the device to determine whether it was functioning. They found it survived the stomach environment and remained powered for 48 hours.

"This is the first reported system that evaluates ingestion status up to two days without any mechanical and electrical degradation," lead author Canan Dagdeviren, who directs the research group Conformable Decoders at the MIT Media Lab, said in a statement.

While there is a lot of work to be done on the device, it presents a promising new avenue for objectively measuring ingestion, something that could eventually be helpful in the treatment of obesity or the monitoring of medication adherence. It could also be modified to monitor pH balance or other vital signs.

"The concepts in materials and characterization methods introduced here provide new routes to monitor vital signs and associated mechanical deformations of the gastric cavity," researchers wrote in the study in Nature. "This in turn could aid in the diagnosis and treatment of motility disorders and in the monitoring of ingestion for applications in the treatment and evaluation of obesity."