Tiny biosensor could mean an end to daily finger sticks for diabetics
By Darren Quick
September 7, 2012
Despite promising developments in recent years, millions of type-1 diabetes sufferers worldwide still face the often-painful daily burden of finger sticks to test their blood glucose levels. Now researchers at the Fraunhofer Institute for Microelectronic Circuits and Systems (IMS) have developed a biosensor that provides a non-invasive way to measure blood glucose levels and can transmit its readings wirelessly to a mobile device.
Instead of sampling a user’s blood, the biosensor can continuously measure glucose levels using other tissue fluids, such as sweat or tears. While such sensors are not new, they have previously been too big, too imprecise and consumed too much power. The new biosensor consists of a chip that measures just 0.5 x 2 mm and consumes less than 100 microamperes at five volts.
The device’s chip integrates a nanopotentiostat that measures the concentrations of hydrogen peroxide (H2O2) and other chemicals that result from an electrochemical reaction that takes place with the aid of an enzyme called glucose oxidase. The device uses the concentrations of these chemicals to calculate the patient’s glucose level. Also integrated into the device’s chip is an analog digital converter that converts the electrochemical signals into digital data, and a transmitter that can send the data wirelessly to a mobile receiver.
This allows the patient to keep a constant eye on their glucose levels using the device, which, because of its low power requirements, can be worn for weeks or months at a time. Additionally, the sensor can also be powered by radio waves.
“In the past, you used to need a circuit board the size of a half-sheet of paper,” says Tom Zimmermann, business unit manager at IMS. “And you also had to have a driver. But even these things are no longer necessary with our new sensor.”
Similar to the electronic contact lens being developed by a team from the University of Washington and Microsoft Research, the tiny biosensor could be placed next to the eye and wirelessly transmit data to an implanted miniature insulin pump that would automatically administer the precise amount of insulin required.
Importantly, the biosensor, which was engineered by researchers at Dutch medical technology firm NovioSense BV, is cost-effective to manufacture and suited to mass production. Both factors that could one day help it make daily finger sticks a thing of the past for diabetes patients.