Teardrop Test for Diabetics

By Ker Than
LiveScience Staff Writer
posted: 18 August 2006
10:43 am ET
 
A device that uses teardrops to measure the amount of sugar in a person's blood could soon allow diabetics to forgo painful daily pinpricks.
 
"I hope in two to three years to have prototypes out and that someday you'll be able to go to a grocery store and test your sugar, just like you test your blood pressure," said project leader Florencio Hernandez of the University of Central Florida.
 
The test involves a gold-salt solution that generates detectable gold nanoparticles when exposed to sugar, also known as glucose. The glucose can come from a person's blood, urine, or tears, but the latter is best, Hernandez said.
 
The amount of shed gold nanoparticles is directly related to glucose concentration and can be read using a CD-sized instrument called a UV-Vis spectrophotometer.
 
The chemical reaction between the gold and sugar is visible: Depending on the concentration of sugar, the solution turns from light pink to a bloody red.
 
A test that makes you cry
 
For all the non-actors out there who can't cry on demand, a substance could be sniffed that stimulates the tear glands. This is why cutting onions can make you cry: chemicals stored different compartments of the onion cell mix together to form an unstable acid; the acid decomposes into a gas which wafts through the air and into one's eyes. Nerve endings in the eyes are stimulated and tears form.
 
"You can't put drops in the eye because that would change the concentration of glucose that you're going to rate," Hernandez told LiveScience.
 
The researchers say the new method would not only be painless, but that it could also provide a way to detect rising sugar levels years before a person would normally visit their doctor for a diabetes test. It could also serve as an early alert for pregnant women at risk for gestational diabetes.
 
"That was the whole idea, to have it be preventative," Hernandez said. "That way, if you see a pattern you can address the problem before it really becomes grave, before the disease does a lot of damage."
 
Diabetes, type 1 and 2, affects 20.8 million people in America, according to the Centers for Disease Control. It is the sixth-leading cause of death nationally and can lead to heart disease, stroke, high blood pressure, blindness, kidney disease and nervous system disorders.
 
Currently, the most common way that diabetics measure their blood-sugar levels is by pricking their fingers to draw blood , which is then read by a machine.
 
Hernandez presented his work at the American Chemical Society national meeting earlier this year.
 
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* Manufactured Nanoparticles Might Pose Health Threat