A Microwave Glucose Sensor Advances Bloodless Diabetes Monitoring

Non-invasive microwave technology could finally end the diabetic's annoying daily routine of pricking their finger to check blood glucose levels.

Researchers at Baylor College of Medicine (Houston, TX, USA) developed an electromagnetic sensor that could provide diabetics a noninvasive alternative to reading their blood glucose levels by determining the glucose dielectric constant. As the energy goes from the sensor through the skin and back to the sensor, the glucose level is measured through the transference of energy. The microwave frequency range is wide enough to isolate the effect of sugar in the blood, and minimize the characteristics of other factors such as body fat and bone, which could alter accurate readings. The researchers claim that using electromagnetic waves is relatively safe because they do not ionize the body's molecules as X-rays can.

To measure glucose levels, users must press their thumb against the sensor. The researchers took samples of nearly 20 people and compared those samples to levels measured with an over-the-counter commercial sensor. The sensor is still in the early stages of development.

"The sensor passed its first simple quantitative test. It can provide useful information to help the user decide what course of action they should take,” said lead investigator Dr. Randall Jean, Ph.D., an associate professor of electrical and computer engineering at Baylor. "This is a relatively new area the market is exploring and we've demonstrated that using microwave energy can work.”

The dielectric constant (also known as relative permittivity) is the ratio of the permittivity of a substance to the permittivity of free space. This constant affects how electromagnetic signals (light, radio waves, microwaves, etc.) move through the material. Dielectrics have the strange property of making space seem bigger or smaller than it looks, and the dielectric constant value tells you how much smaller or bigger the space gets. A high value of dielectric constant makes the distance inside the material look "bigger”; materials with high dielectric constants are useful in the manufacture of high-value capacitors.


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