Engineers at Massachusetts Institute of Technology developed an ingestible jelly-like smart pill that could stay in the stomach for up to 30 days.
The pill quickly expands into a ping pong-sized ball, which has the ability to monitor temperature in the gastrointestinal tract. The scientists behind the experiment said that the device could monitor ulcers, cancers, and other GI conditions in the long term.
The ingestible pill equipped with a sensor can safely pass through the digestive tract. The person only needs to drink a calcium solution to shrink the pill back to its original size.
The pill is made using two types of hydrogels, which is similar to the texture and consistency of Jell-O. The combination of polymers and water makes the pill impermeable to the natural acidity of the gut environment while maintaining its ability to change in size.
"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," said Xuanhe Zhao, coauthor and an associate professor of mechanical engineering at MIT.
The Jell-O-like smart pill exceeds the expectations from the current ingestible sensors whose half-life is only up to a few days. Since the new pill is designed out of hydrogels, it is softer and more biocompatible compared to previous prototypes that are made of plastic or metal.
Inspired By Fish
The design of the Jell-O smart pill is inspired by the defense mechanisms of certain species such as pufferfish or blowfish. When threatened, the pufferfish will quickly inflate into a spiky balloon by sucking in a large amount of water under a short period of time.
"Hydrogels offer new opportunities for human-machine interactions due to their superior mechanical compliance and biocompatibility," the authors reported in the study published in the journal Nature Communications.
"Large animal tests support the exceptional performance of the ingestible hydrogel device for long-term gastric retention and physiological monitoring."
The researchers realized that the super absorbency of the pill will likely cause the breaking of its particles as it pass through the stomach. To protect the sensor, they designed a second protective layer made of nanoscopic gridlock pattern equipped with an anti-fatigue feature.
To test its feasibility, the scientists submerged the pill into solutions of water and fluid similar to the gastric juices found in the stomach. They found that the smart pill inflated up to 100 times its original size in about 15 minutes.