Fraunhofer Researchers Develop New Blood Glucose Biosensor

Fraunhofer is joining the legions of researchers determined to relieve diabetes patients of the burden of pricking a finger everyday to test their blood glucose levels. For just this purpose, researchers at the Fraunhofer Institute for Microelectronic Circuits and Systems (IMS; Duisburg, Germany) have developed a biosensor combining measurement and digital analysis capability that can relay information to a mobile device.

Previous biosensors for measuring blood glucose levels were too large and imprecise. In addition they consumed too much power. In contrast, the Fraunhofer researchers' nanoscale sensor overcomes these obstacles. It measure blood glucose using an electrochemical reaction that is activated with the aid of an enzyme. Glucose oxidase converts glucose into hydrogen peroxide and other chemicals whose concentrations can be measured using a potentiostat. This measurement is used for calculating glucose levels.

Measuring 0.5 x 2.0 mm, the sensor can accommodate more than the nanopotentiostat itself. The Fraunhofer researchers have attached the entire diagnostic system to it. "It even has an integrated analog digital converter that converts the electrochemical signals into digital data," explains Tom Zimmermann, business unit manager at IMS. By transmitting the data via a wireless interface, the biosensor enables patients to monitor their glucose levels constantly. "In the past, you used to need a circuit board the size of a half-sheet of paper," Zimmermann adds. "And you also had to have a driver. But even these things are no longer necessary with our new sensor."

In addition to its miniature size, the sensor consumes substantially less power than previous technologies. For example, earlier systems required about 500 mA at 5 V, while the new technology requires less than 100 mA. This capability increases the durability of the system, enabling patients to wear the sensor for weeks or even months. This durability is acehived by the use of a passive system. The sensor can send and receive data packages, but it can also be supplied with power through radio frequency.

Eventually, this noninvasive blood glucose biochip could also possibly be used to control implanted miniature insulin pumps.