Sensor uses carbon nanotubes to test saliva for glucose

MIT Technology Review : A new way to test people’s glucose levels should make that process less painful for people with type 2 diabetes. Current tests rely on blood samples drawn from finger pricks. Now Mitchell Lerner of the University of Pennsylvania in Philadelphia and colleagues have developed a carbon nanotubeâbased transistor that can detect glucose levels in a variety of body fluids, including saliva. The nanotubes are coated with molecules of pyrene-1-boronic acid, which makes then highly sensitive for glucose detection. When exposed to glucose, the nanotube transistor’s current-voltage curve changes, and that change can be measured to indicate the glucose concentration. Although the technology has been around for a while, what the research team did was find a way to make the tubes quickly and cheaply. The system is less useful for type 1 patients, who have to give themselves daily injections of insulin. Because it takes at least 30 minutes for the glucose to show up in saliva, the device cannot quickly give an accurate reading of the blood glucose levels.