Flexible, ingestible sensor detects GI tract disorders
Measuring 2 by 2.5 cm, the flexible device uses piezoelectric materials that generate a current and voltage when mechanically deformed. Once ingested, the sensor adheres to the stomach wall or intestinal lining, where it can measure the rhythmic contractions of the digestive tract.
Such sensors, say the researchers, could help doctors diagnose gastrointestinal disorders that slow down the passage of food through the digestive tract, which can result in difficulty swallowing, nausea, gas, or constipation. In addition, they could also be used to detect food pressing on the stomach, which could help doctors monitor food intake of patients being treated for obesity.
“Having flexibility has the potential to impart significantly improved safety, simply because it makes it easier to transit through the GI tract,” says Giovanni Traverso, a research affiliate at MIT’s Koch Institute for Integrative Cancer Research, a gastroenterologist and biomedical engineer at Brigham and Women’s Hospital, and one of the senior authors of a paper on the research.
The sensor comprises two electrodes: a gold electrode placed on top of a ceramic perovskite piezoelectric material called PZT, and a platinum electrode on the underside of the PZT. Once the circuit is fabricated on silicon, it is removed and printed onto a flexible polymer, called polyimide.
The sensor can then be rolled up and placed in a dissolvable capsule that is easily swallowed. In tests in pigs, the sensor successfully adhered to the stomach lining after being delivered endoscopically. Through external cables, the researchers were able to see transmitted information about how much voltage the piezoelectrical sensor generated and then calculate how much the stomach wall was moving, as well as tell when food or liquid was ingested.
“For the first time, we showed that a flexible, piezoelectric device can stay in the stomach up to two days without any electrical or mechanical degradation,” says Canan Dagdeviren, an assistant professor in MIT’s Media Lab and the director of the Conformable Decoders research group, and the paper’s lead author.
Next, the researchers plan to harvest some of the energy generated by the piezoelectric material to power other features, including additional sensors and wireless transmitters. Such devices would not require a battery, which would further improve their potential safety, the researchers say.
For more, see “Flexible piezoelectric devices for gastrointestinal motility sensing.”
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