UC San Diego researchers develop a self-powered ingestible sensor system designed to monitor metabolites in the small intestine over time. Credit: David Ballot for the Jacobs School of Engineering, UC San Diego
Key Points:
- Researches developed a battery-free ingestible biosensing system that can provide continuous monitoring inside the body.
- Measurements of the intestinal environment provide a critical component of tracking overall gastrointestinal health, a major factor in studying nutrition, diagnosing and treating various diseases, preventing obesity and more.
- The battery-free “smart pill” uses glucose present in the intestines as a biofuel to power the device.
Researchers have developed a battery-free, pill-shaped ingestible biosensing system designed to provide continuous monitoring in the intestinal environment.
“In our experiments, the battery-free biosensor technology continuously monitored glucose levels in the small intestines of pigs 14 hours after ingestion, yielding measurements every five seconds for two to five hours,” said Ernesto De La Paz Andres, a nanoengineering graduate student at UC San Diego and one of the co-first authors on the paper.
Older methods for directly monitoring the inside of the small intestine can cause significant discomfort for patients while generating only single short data recordings of an environment that continuously changes. By contrast, this biosensor provides access to continuous data readings over time.
To address shortcoming of previous “smart pills,” the UC San Diego team developed a self-powered glucose biofuel biosensor integrated into a circuit that performs energy harvesting, biosensing and wireless telemetry using a power-to-frequency conversion scheme utilizing magnetic human body communication.
The unique battery-free operation is made possible by the team's glucose biofuel cell (BFC) for obtaining power during operation while simultaneously measuring changing glucose concentrations. Its energy-efficient magnetic human body communication (mHBC) scheme operates in the 40-200 MHz range to receive the time-resolved transmitted signals.
“It uses glucose present in the intestines as a biofuel to power the device,” said Mercier. “Making this all work with ultra-low-power electronics and with a stable yet small glucose biofuel cell were major technical challenges that were addressed here.”
The proof-of-concept smart pill measures 2.6 cm in length and 0.9 cm in diameter. So far, small intestine data recording has only been performed in pigs, which have a similar size GI tract to humans. But, the researchers say their next step is to reduce the size of the pills to make them easier for humans to swallow.
Information provided by UCSD.