MIT researchers built an in-house sensor equipped with genetically engineered bacteria that can diagnose bleeding in the stomach or other gastrointestinal problems. “Bacteria-on-a-chip” includes sensors from living cells and ultra-low power electronics that can transmit a bacterial response to a wireless signal that can be read using a smartphone.
“By combining the designed biological data with low-power wireless electronics, we can detect biological signals in the body almost in real time, thus obtaining new diagnostic tools, “says Timothy Lou, assistant professor of MIT in electrical engineering, computer science and bioengineering.
In a new study that appeared on May 24 in Sciennce, scientists created sensors that react to the heme, a component of blood, and showed their performance on pigs. They also developed sensors capable of responding to a molecule that signals inflammation.
Lou and Ananta Chandrakasan, dean of the engineering school of the Massachusetts Institute of Technology and professor of electrical engineering and computer science Vannevar Bush, were senior authors of the study. Lead authors were graduate student Mike Maymi and postdoctor Philippe Nadeo.
They placed the bacteria in four wells on a specially designed sensor coated with a semipermeable membrane that allows passage of small molecules from the environment. Under each well is a phototransistor capable of measuring the amount of light produced by bacterial cells and transferring information to a microprocessor that sends a wireless signal to the nearest computer or smartphone. The data can be analyzed via an Android application.
A sensor that is a cylinder about 1.5 inches in length requires about 13 microwatts of power. Researchers equipped the sensor with a 2.7-volt battery, which, according to their estimates, can drive the device for 1.5 months of continuous use. They say that the battery can be fed with acidic liquids in the stomach.
“The focus of this work is on the design and integration of a system that combines the power of bacterial sensing with ultra-low power to implement important applications for assessing health status,” says Chandrakasan.  Briefly, this sensor allows you to bypass unnecessary procedures. You can simply swallow the capsule, and in a relatively short period of time, you will find out whether bleeding has occurred. In the future, scientists plan to reduce the size of the sensor and study how long bacteria can survive in the digestive tract. They also hope to develop sensors for gastrointestinal diseases, not just for bleeding.