Genetically engineered bacteria lets ingestible sensor monitor gut health

Team of researchers at MIT has produced a novel "bacteria on a chip" system that combines genetically engineered bacteria that can detect intestinal bleeding with an ingestible electronic circuit that can wirelessly send a signal to a nearby computer. 

"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, one of the MIT researchers working on the project.

To begin, the team genetically engineered a probiotic strain of E. coli bacteria to respond to the presence of a chemical compound call heme, a compound found within red-blood cells and has been shown to be a reliable biomarker of internal bleeding. Upon encountering heme, the engineered bacteria emits a small amount of light.

The next step was developing a way to transport these bacterial sensors through a body and translate the signals into data that can be transmitted instantly. A capsule was created with four wells that hold the bacteria. Molecules from the body permeate through a membrane into the wells and, in the presence of heme, trigger the bacteria to emit light. That light is then measured by a phototransistor underneath each well which wirelessly relays the data to a nearby smartphone or computer.