Researchers Finish Work on Needle-free Glucose Tester

By Claire Swedberg

Sept. 30, 2008—A team consisting of Georgetown University's Georgetown Advanced Electronics Laboratory (GAEL) researchers, Science Applications International Corp. (SAIC), and Gentag, has finished development on a glucose measuring system that, once commercially available, would allow diabetics to monitor their glucose levels electronically—using an RFID-enabled cell phone—without needing to prick their fingers.

SAIC researchers worked with Georgetown University on the research and development of the glucose sensor technology, which has been tested thus far only on animals with the exception of Georgetown associate physics professor Mak Paranjape, who tested the system on himself. Gentag provided passive RFID technology. The companies are awaiting FDA approval for the commercial sale of glucose-monitoring products that use the RFID-based sensors. Because the technology is considered non-invasive, human testing would not be necessary. The companies are hoping to sign a licensing agreement with a company seeking to manufacture and distribute such a system, which Gentag president and CEO John Peeters predicts will be a popular alternative to the current painful and expensive glucose-testing methods being used by diabetics.

Georgetown physics professor Mak Paranjape

Diabetics have to keep a close eye on their blood sugar, requiring them to measure their glucose level anywhere from two times a day to every 15 minutes, depending on the type of diabetes they have, explains Paranjape, who shares a patent for the sensor technology with Georgetown University and SAIC. Typically, diabetic patients use a disposable lancet to prick a fingertip to draw blood and testing strips on which the blood is collected and tested. This costs about 75 cents per test, estimates Peeters. The pain and cost both tend to discourage many from testing as often as they should.

The solution developed by Paranjape with Gentag and SAIC centers on a skin patch containing a noninvasive sensor that can measure a person's glucose level and transmit the result to a handheld reader or cell phone. The skin patch is similar in appearance to a Band-Aid, says Paranjape, with the actual sensor and battery as well as Gentag's RFID chip and antenna incorporated inside.

The glucose sensor contains a tiny heating element powered by a small battery. Each time the sensor takes a glucose reading, the element warms to about 130 degrees Celsius for 30 milliseconds, burning through the outermost level of dead skin cells in spaces about the diameter of a human hair. The heated outer layer allows access to interstitial fluid beneath that layer, which the sensor then uses to assay the level of sugar. In this scenario, the user wouldn't feel a thing, says Paranjape, who adds that he felt no pain when trying it on himself.

An adhesive skin patch (above) contains a passive 13.56 MHz RFID tag wired to a battery-powered noninvasive sensor (below) that measures a person's glucose level.