- An ingestible sensor can detect bleeding in the stomach and other
- The sensor contains genetically modified bacteria that can
sense environmental conditions and relay information to an electronic
- The sensor requires very low-power and enables us to detect
biological signals in the body and in real-time.
A 'bacteria-on-a-chip' developed
by a research team at MIT can diagnose bleeding in the stomach and other
gastrointestinal problems. The chip is an ingestible sensor that carries
genetically modified bacteria that can sense environmental conditions and relay
the information to an electronic circuit. The study is published in Science
The team used living cells to make
the ingestible sensor
. It uses ultra-low-power
electronics that convert the bacterial response into a wireless signal that can
be read by a smartphone.
"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.
We have come a long way using bacteria to respond to stimuli such as
environmental pollutants or markers of disease. The bacteria are engineered to
produce outputs such as light when they detect the target stimulus. However,
specialized equipment is usually required to measure this response.
‘An ingestible sensor with bacteria programmed to sense environmental conditions and relay the information to an electronic circuit can detect bleeding in the stomach.’
The team at MIT wanted to create a sensor
that could translate the bacterial
response into a wireless signal.
The cylindrical, 1.5 inch sensor was created to respond to heme, a
component of blood and requires about 13 microwatts of power. The team has also
designed sensors that can respond to a molecule that is a marker of inflammation
The initial demonstration was focused on detecting bleeding in the GI
tract. A probiotic strain of E. coli was engineered to express a genetic
circuit that causes the bacteria to emit light when they encounter heme.
The bacteria were placed into four wells on their custom-designed sensor
and covered by a semipermeable membrane. The membrane allows small molecules
from the surrounding environment to diffuse through. A phototransistor under
each cell measures the amount of light produced by the bacteria and relays the
information to a microprocessor that sends a wireless signal to a nearby
computer or smartphone. An Android app was also developed to analyze the data.
The ingestible sensor was tested in pigs and the team showed that it
could correctly determine bleeding in the stomach.
Patients suspected to be bleeding from a gastric ulcer
currently have to undergo an endoscopy
to diagnose the problem,
which often requires sedation.
"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," says Mark Mimee, coauthor of the study.
The team is working to reduce the size of the ingestible sensor and
increasing the time that bacteria can survive in the GI.
The team has also developed other sensors; one which detects a
sulfur-containing ion called thiosulfate, linked to inflammation. This could be
used to monitor patients with Crohn's
or other inflammatory conditions. The second sensor detects a
bacterial signaling molecule called AHL, which can serve as a marker for
- Ingestible "bacteria on a chip" could help diagnose disease - (http://news.mit.edu/2018/ingestible-bacteria-on-a-chip-help-diagnose-disease-0524)
- An ingestible bacterial-electronic system to monitor gastrointestinal health - (http://science.sciencemag.org/content/360/6391/915)