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No more needle pricks for diabetics
 

Diabetics will celebrate when they no longer have to prick their finger every day to get that drop of blood to put on a strip to check their blood glucose level. Well, that day of celebration could be just around the corner if technology developed by researchers in Germany is commercialised.

Researchers at raunhofer Institute for Microelectronic Circuits and Systems IMS in Duisburg, Germany have developed a tiny biosensor that measures glucose levels continuously using tissue fluids other than blood, such as in sweat or tears. The nano chip combines measurement and digital analysis, which can be radioed to a mobile device. For many diabetics, this means of checking blood glucose is an everyday part of life. Especially for patients with Type-1 diabetes, who always have to keep a close eye on their glucose levels, since their bodies are incapable of producing the insulin to break down the glucose in the blood. Several times a day, they have to place a tiny drop of blood on a test strip. It is the only way they can ascertain the blood glucose value, so they can inject the correct amount of insulin needed. And this pricking is not only burdensome; it may also cause inflammation or cornification of the skin. And for pain-sensitive patients, the procedure is agony.

The new technology could enable diabetics to dispense with the constant needle pricks. In the past, such bioelectric sensors were too big, too imprecise and consumed too much power, but the researchers have now achieved a major breakthrough: They have developed a biosensor in nano-form – measuring just 0.5 x 2.0 millimetres – that circumvents these hurdles.

The device works by measuring an electrochemical reaction that is activated with the aid of an enzyme. Glucose oxidase converts glucose into hydrogen peroxide (H2O2) and other chemicals whose concentration can be measured with a potentiostat. This measurement is used for calculating the glucose level.

The tiny device not only houses the potentiostat, but also the entire diagnostic system.

“It even has an integrated analog digital converter that converts the electrochemical signals into digital data,” explained Tom Zimmermann, business unit manager at IMS. The biosensor transmits the data via a wireless interface, for example to a mobile receiver. In this way the patient can keep an eye on his or her glucose level. “In the past, you used to need a circuit board the size of a half-sheet of paper,” says Zimmermann. “And you also had to have a driver. But even these things are no longer necessary with our new sensor.”

Minimal power

The small size is not the only thing that provides a substantial advantage over previous biosensors of this type. In addition, the sensor consumes substantially less power. Earlier systems required about 500 microamperes at five volts; now, it is less than 100 microamperes. That increases the durability of the system – allowing the patient to wear the sensor for weeks, or even months. The use of a passive system makes this durability possible. The sensor is able to send and receive data packages, but it can also be supplied with power through radio frequency.

The glucose sensor was engineered by the researchers at Noviosens, a Dutch medical technology firm. Since it can be manufactured so cost-effectively, it is best suited for mass production. These noninvasive measuring devices for monitoring blood glucose levels may become the basis for a particularly useful further development in the future: The biochip could control an implanted miniature pump that, based on the glucose value measured, indicates the precise amount of insulin to administer. That way, diabetes patients could say goodbye to incessant needlepricks forever.
 

 Date of upload: 20th Nov 2012

 

                                  
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