Researchers at MIT have developed an ingestible chip containing genetically engineered E. coli. When swallowed, the bacteria can detect blood in the stomach, and produce light. The chip contains components that measure the amount of light produced and relays this information to a nearby smartphone, allowing a simple and non-invasive diagnosis of gastrointestinal bleeding.
In the past ten years, researchers have made progress in creating genetically modified bacteria that can respond to external stimuli. The MIT research team took this approach one step further to a real-world application, and cleverly packaged the bacteria in a diagnostic chip that can be swallowed.
“Our idea was to package bacterial cells inside a device,” said Phillip Nadeau, a researcher involved in the study. “The cells would be trapped and go along for the ride as the device passes through the stomach.”
The researchers engineered bacteria to produce light when they encounter heme, a component of blood. The device consists of a 1.5 inch cylinder, which contains the bacteria in wells that are covered by a semi-permeable membrane. This membrane allows components from the stomach to interact with the bacteria, but keeps the bacteria themselves safely enclosed.
By including a phototransistor under each well that can measure the light emitted by the bacteria, and incorporating additional components to relay data wirelessly to a nearby smartphone, the researchers created a device that can detect gastrointestinal bleeding non-invasively. They also developed an android app to display this diagnostic information.
So far, the research team has shown that the chip can detect gastrointestinal bleeding in pigs. However, the system also has significant potential for a range of other diagnostic applications. “Most of the work we did in the paper was related to blood, but conceivably you could engineer bacteria to sense anything and produce light in response to that,” said Mark Mimee, another researcher involved in the study. “Anyone who is trying to engineer bacteria to sense a molecule related to disease could slot it into one of those wells, and it would be ready to go.”