A common problem, though, is that smart pills tend to quickly pass through the digestive system, limiting their use to a short period.
Now, researchers from MIT may have come up with a solution. They created a smart pill that swells to 100 times its original size within 15 minutes of entering a person’s stomach, trapping it there for long periods — and they have no shortage of ideas for how their smart pill could improve human health.
Pigs and Ping Pong
The MIT researchers describe the smart pill in a paper published on Wednesday in the journal Nature Communications.
The team used two hydrogel materials to create their pill. One of the materials contains super-absorbent particles known as sodium polyacrylate. The other material is made from tiny crystalline chains arranged in a grid-like pattern. This second material acts as a covering for the first, preventing it from breaking apart when it expands in the stomach.
When they tested the pill in liquids designed to mimic stomach fluids, the pill swelled up to the “size of a soft, squishy ping-pong ball,” according to an MIT News story — though a video of the pill, ominously, makes it look closer to the size of a grapefruit. It was also extremely tough, capable of withstanding forces far greater than it would ever experience in a human stomach.
The researchers also figured out that drinking a solution of calcium ions would cause the pill to shrink, allowing it to pass through the digestive system.
To test the smart pills’ utility, the MIT team embedded small temperature sensors into several and fed them to pigs, which have stomachs similar to those of humans. When they retrieved the pills from the animals’ stool, they found the embedded sensors accurately tracked the temperatures of the animals’ innards for 30 days.
Although the current version of the smart pill can only record temperature, the researchers envision numerous other potential applications. Future pills could monitor pH levels, hunt for signs of certain bacteria or viruses, or take images of tumors or ulcers.
There’s even a possibility the pill could help people lose weight by serving as an alternative to gastric balloons, which doctors place in patients’ stomachs using endoscopes.
“With our design, you wouldn’t need to go through a painful process to implant a rigid balloon,” researcher Xuanhe Zhao told MIT News. “Maybe you can take a few of these pills instead, to help fill out your stomach, and lose weight. We see many possibilities for this hydrogel device.”