Could diabetics test their blood sugar with an iPhone?
Research • Tiny sensors in skin show promise for pain-free glucose reading.
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In order to live, 14-year-old Jenny Asay has to poke herself with a needle more than a dozen times a day.

Before they take even a bite of food, those who suffer from Type 1 diabetes — in which the pancreas fails to produce insulin — have to prick themselves in the finger to determine the glucose level of their blood. Then they have to inject insulin with a syringe or an insulin pen to keep their glucose within a healthy range and avoid going into diabetic shock.

"I've gotten used to it," the Magna teen said. "You do it enough times, you just ignore the pain."

There are 25.8 million people in the U.S. — 8.3 percent of Americans — who have Type 1 and Type 2 diabetes, according to the American Diabetes Association. Diabetes contributed to the deaths of 231,404 Americans in 2007, the latest year for which fatality statistics were available from the ADA.

Finding a way to test glucose levels without the constant finger pricking is the "Holy Grail" for diabetics, and a Northeastern University pharmaceuticals professor in Boston thinks she has a nonintrusive way to do it — with an iPhone.

It turns out glucose is also in the skin. Heather Clark's idea is to inject microscopic nanosensors into the skin, much like an invisible tattoo.

She and some of her students are developing a system in which a blue LED light and optical filter attached to an iPhone would shine on the nanosensor tattoo. The phone's camera would snap a picture, and an app would read the amount of light reflected off the tattoo to determine the person's glucose level.

"We don't know the accuracy yet," Clark said. "But we feel very optimistic about it. As phone technology gets better and better, this will get better and better."

An accurate, noninvasive test would be a huge step forward for diabetics, who can have increased risks of heart disease, blindness and kidney disease.

"That is kind of the Holy Grail of where everybody wants to get to," said M. Sue Kirkman, a doctor and senior vice president of medical affairs and community information for the American Diabetes Association. "I think there are certainly a lot of studies and people trying to figure out ways to do it noninvasively. But the chemistry of it is difficult to accomplish because glucose isn't a molecule that you can detect easily without getting into it [in the blood]."

One hurdle to the technology is that glucose levels in the skin lag behind the levels in the blood by five to 10 minutes, said Gitana Staskus, an assistant professor of medicine at the University of Utah who specializes in endocrinology.

"If we do a finger-stick test to measure blood sugar levels and it shows 200 [milligrams per deciliter glucose level], the sensor under the skin may still show it's 140," she said. "They're still not very accurate."

There are other meters that read glucose within the skin instead of the blood, but they monitor levels over a long period of time to determine trends.

Researchers have not found a way to monitor blood sugar with a needle or catheter in the bloodstream for long periods for fear it would cause clotting or infection. But doctors are trying to develop technology that constantly monitors a diabetic's blood and automatically administers insulin when needed — essentially an artificial pancreas.

Clark said her technology is not yet ready for human trials and she doesn't know when it could be ready for market, but some pharmaceutical companies have expressed interest in her research since it was released last month.

Meanwhile, others also are researching gene therapy that could help repair a diabetic's pancreas.

It's all in an effort to help people like 14-year-old Jenny, who for now frequently have to stick themselves with a needle as a part of their daily routine.

A noninvasive test "would be pretty important, really important," said Jenny's mother, Virginia Asay. "She has a harder time now with just being in junior high and her friends not having to do it. She just wants to be like a regular teenager."

vince@sltrib.com

Twitter: @ohmytech

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