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Ingestible ‘bacteria on a chip’
CAMBRIDGE, Mass.—Researchers at the Massachusetts Institute of Technology (MIT) recently built an ingestible sensor—a “bacteria-on-a-chip” approach that combines sensors made from living, genetically engineered cells with ultra-low-power electronics—that they say can diagnose bleeding in the stomach or other gastrointestinal problems. Once ingested, the sensor converts the bacterial response into a wireless signal that can be read by a smart phone.
“By combining engineered biological sensors together with low-power wireless electronics, we can detect biological signals in the body and in near real-time, enabling new diagnostic capabilities for human health applications,” says Timothy Lu, an MIT associate professor of electrical engineering and computer science and of biological engineering.
The study highlighting the new technology appeared in the May 24 online edition of Science.
For this study, the researchers created sensors that respond to heme, a component of blood, and showed that they work in pigs. They also designed sensors that can respond to a molecule that is a marker of inflammation.
For their initial demonstration, the researchers focused on bleeding in the gastrointestinal tract, engineering a probiotic strain of E. coli to express a genetic circuit that causes the bacteria to emit light when they encounter heme.
The sensor, which is a cylinder about 1.5 inches long, requires about 13 microwatts of power. The researchers equipped the sensor with a 2.7-volt battery, which they estimate could power the device for about 1.5 months of continuous use. They say it could also be powered by a voltaic cell sustained by acidic fluids in the stomach, using technology that certain members of the team had previously developed.