There are a variety of gastrointestinal conditions that may be better treated if clinicians had an idea of what’s going on inside the stomach. But, the stomach is full of acid and it eventually expels whatever drops into it, making it difficult to have sensors operate inside for long periods of time. Researchers at MIT have now developed a way to drop sensors into the stomach that will remain there until patients are ready for them to come out.
The new devices are made of hydrogels, a gelatin-like substance, and sodium polyacrylate, a highly absorbent material. They are about the size of a pill, but once swallowed they absorb water from the stomach and expand and become closer to the size of a golf ball. Being so large, the stomach cannot empty them and they remain indefinitely stuck. The trick to getting rid of these balls is to drink a solution rich in calcium ions, which shrinks the balls and lets them proceed into the small intestine.
They hydrogel balls can have different sensors inside, and so far thermometers have been successfully integrated and tested in laboratory pigs. The devices were able to track the temperature inside the pig stomachs for a month at a time, and they exited with few problems.
Here’s a time lapse showing the hydrogel devices expanding in water:
Here’s an MIT video about the research:
Study in Nature Communications: Ingestible hydrogel device…