Graphene based wearable sensor for disease monitoring
Scientists of the University of Michigan are working on a new wearable vapour sensor that could one day offer continuous disease monitoring for patients with diabetes, high blood pressure, anemia or lung disease. The new sensor, which can detect airborne chemicals either exhaled or released through the skin, according to its creators would likely be the first wearable to pick up a broad array of chemical, rather than physical, attributes.
As the researchers report nanoelectronic sensors typically depend on detecting charge transfer between the sensor and a molecule in air or in solution. However, these previous techniques typically led to strong bonds between the molecules being detected and the sensor itself. That binding leads to slow detection rates. Instead of detecting molecular charge the U-M team, which is working with the National Science Foundation's Innovation Corps program, uses a technique called heterodyne mixing, which looks at the interaction between the dipoles associated with these molecules and the nanosensor at high frequencies.
This technique, made possible through the use of graphene, results in extremely fast response times of tenths of a second, as opposed to the tens or hundreds of seconds typical in existing technology. It also dramatically increases the device's sensitivity. The sensor can detect molecules in sample sizes at a ratio of several parts per billion.
These nanoelectronic graphene vapor sensors can be completely embedded in a microgas chromatography system, which is the gold standard for vapor analysis, the researchers say. The entire microgas chromatography system can be integrated on a single chip with low power operation, and embedded in a badge-sized device that can be worn on the body to provide noninvasive and continuous monitoring of specific health conditions.