Scientists have sought for ways they can comfortably diagnose bleeding in the digestive tract for years, but with limited success. However, using a new technique they call, bacteria-on-a-chip, where the patient is required to swallow a battery-powered sensor, things might change for the better.
MIT researchers have managed to develop an ingestible sensor that is able to detect bleeding in the stomach. The sensor is designed with a special bacterial programmed to analyze its surrounding environment then pass the info to an electronic circuit.
Merging Biological Sensors with Electronics
In the new study published on Science, Timothy Lu, a computer scientist, and professor in electrical engineering explains that combining low power electronics with biological sensors is possible and can be used to detect biological signals in near real-time, right inside the body.
This, in essence, points to the idea that sensors can be used for diagnostic tools to analyze delicate organs. And generally lowering the risks involved with handling internal body systems.
The sensors created do respond to heme, a special constituent of blood. Tests show that the concept works quite well in pigs. To maximize the idea, the scientist made separate sensors that respond to inflammation inside the digestive tract.
Synthetic biologists have in the past managed to achieve milestones in engineering bacteria to have it respond to pollutants, disease pathogens, and stimuli. In this case, the bacteria give signals in form of a light, which ideally would be translated as the target stimulus.
Besides having light as the output signal, other techniques like sound production can be invented. Nonetheless, whichever route is taken, the response must be measured by specialized lab equipment for details and clarity. The original idea here was, trying to make these bacteria profitable in the real-world by transcoding the response of the bacteria into a wireless signal.
“We thought we can take advantage of how the bacteria behave, by packaging its cells inside a device. That way we would have the cells caged in one place and send them into the digestive system,” Nadeau explained.
The Bacteria Powered Sensors in Details
The team focused more on bleeding in their presentation of the concept. And using a genetic circuit, they mechanized a probiotic strain of E.coli that causes the bacteria to send a light signal once it encounters heme.
After having a custom design for the sensors, the scientists placed the bacteria into different wells. Then covered the wells with a semipermeable membrane so as to allow diffusion of small molecules.
Below each well, they placed a hypersensitive phototransistor for measuring the amount of light relayed by the bacteria cells, which forwards the data to a tinny processor that then sends signals to the receiving gadget outside the body.
The sensor is 1.5” long. It’s powered by a 2.7-volt battery and only requires 13 microwatts of power to function. The experts are also confident that acidic fluids in the stomach might power the ‘gadget’ –linking the possibility from another technology suggesting the same.
How This Affects Disease Diagnosis
The MIT team says they’ve tested the ingestible sensor and confirmed that it accurately revealed bleeding or blood traces in the stomach. If approved, the experts think this is a quick option to analyze the digestive system. And depending on situations, the sensor can either be placed in the digestive tract one-time or longer (up to 1.5 months of guaranteed function).
The overall intent of this ‘ingestible’ bacteria-on-a-chip tech is to avoid endoscopy, a procedure that requires the patient to be sedated so as to undergo digestive system bleeding diagnosis (often caused by gastric ulcer). In other words, it means a simple ingesting of the ‘capsule’ the patient and the doctor alike would know whether there was any bleeding event in the past, or at present.