Researchers at MIT have designed a smart pill that, once it reaches the stomach, swells to the size of a ping-pong allowing it to stay in the stomach for up to a month. During that time, a sensor in the pill continuously tracks the stomach's temperature and other GI conditions. The smart pill is comprised of two types of hydrogels that mimic the consistency of Jell-O enabling it to quickly swell in size while being impervious to the stomach's acidic environment. If the pill needs to be removed, the patient only has to drink a calcium solution to trigger the pill back to its original size so it can safely pass through the body. The team's research was recently published in the journal Nature Communications.
“The dream is to have a Jell-O-like smart pill, that once swallowed stays in the stomach and monitors the patient’s health for a long time such as a month,” says Xuanhe Zhao, lead author of the study and associate professor of mechanical engineering at MIT.
From the MIT article: "The design they ultimately landed on resembles a small, Jell-O-like capsule, made from two hydrogel materials. The inner material contains sodium polyacrylate — superabsorbent particles that are used in commercial products such as diapers for their ability to rapidly soak up liquid and inflate.
The researchers realized, however, that if the pill were made only from these particles, it would immediately break apart and pass out of the stomach as individual beads. So they designed a second, protective hydrogel layer to encapsulate the fast-swelling particles. This outer membrane is made from a multitude of nanoscopic, crystalline chains, each folded over another, in a nearly impenetrable, gridlock pattern — an “anti-fatigue” feature that the researchers reported in an earlier paper."
Read more about the inflatable pill that tracks GI conditions long term at MIT.