Ingestible 'Bacteria on a Chip' Could Help Diagnose Disease

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Diagnosing Disease

The researchers tested the ingestible sensor in pigs and showed that it could correctly determine whether any blood was present in the stomach. They anticipate that this type of sensor could be either deployed for one-time use or designed to remain the digestive tract for several days or weeks, sending continuous signals.

Currently, if patients are suspected to be bleeding from a gastric ulcer, they have to undergo an endoscopy to diagnose the problem, which often requires the patient to be sedated.

“The goal with this sensor is that you would be able to circumvent an unnecessary procedure by just ingesting the capsule, and within a relatively short period of time you would know whether or not there was a bleeding event,” Mimee says.

To help move the technology toward patient use, the researchers plan to reduce the size of the sensor and to study how long the bacteria cells can survive in the digestive tract. They also hope to develop sensors for gastrointestinal conditions other than bleeding.

In the Science paper, the researchers adapted previously described sensors for two other molecules, which they have not yet tested in animals. One of the sensors detects a sulfur-containing ion called thiosulfate, which is linked to inflammation and could be used to monitor patients with Crohn’s disease or other inflammatory conditions. The other detects a bacterial signaling molecule called AHL, which can serve as a marker for gastrointestinal infections because different types of bacteria produce slightly different versions of the molecule.

“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,” Mimee says. “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.”

The researchers say the sensors could also be designed to carry multiple strains of bacteria, allowing them to diagnose a variety of conditions.

“Right now, we have four detection sites, but if you could extend it to 16 or 256, then you could have multiple different types of cells and be able to read them all out in parallel, enabling more high-throughput screening,” Nadeau says.

The research was funded by Texas Instruments, the Hong Kong Innovation and Technology Fund, the Office of Naval Research, the National Science Foundation, the Center for Microbiome Informatics and Therapeutics, Brigham and Women’s Hospital, a Qualcomm Innovation Fellowship, and the Natural Sciences and Engineering Council of Canada. Chip fabrication was provided by the TSMC University Shuttle Program.

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