Smart contact lenses may one-day test sugar levels

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CONTACT lenses packed with transparent sensors might one day help people with diabetes to monitor their blood sugar levels, a new study finds.
These sugar-sensing lenses would give people a way to check their blood sugar levels without drawing blood, according to the scientists who are developing on the ices.
Typically, people with diabetes monitor their blood sugar by making a tiny prick in their fingertip to draw blood, and then using a small device to measure blood sugar levels. It hurts, and some have to do this several times a day. But the proposed contact lenses could continuously monitor a person’s blood sugar levels throughout the day, said study co-author Gregory Herman, a chemical engineer at Oregon State University. Such continuous monitoring could help reduce the risk of diabetes-related health problems, by alerting someone about any major changes in his or her blood sugar levels right when they happen, Herman said. (In an individual who has diabetes, the body cannot effectively transport sugar, or glucose, from the blood to that person’s cells. Too much glucose in the blood can lead to medical problems.)
Devices that continuously monitor blood sugar levels are available, but they often require the insertion of electrodes under the skin, which can be painful, lead to skin irritation or infections, and must get replaced every several days. Contact lenses that could continuously and noninvasively monitor blood sugar levels could eliminate many of these problems, Herman said. And because contact lenses are virtually invisible, people could use them without feeling self-conscious, he added.
To make the blood-sugar-monitoring contact lens, the researchers used technology that was originally developed for electronic products. Specifically, the researchers tinkered with a material called indium gallium zinc oxide (IGZO), whose electronic properties have recently helped boost the image quality in smartphone, tablet and flat-panel displays while also saving power and improving touch-screen sensitivity. “If you buy an iPhone or an Apple computer or a flat-screen TV nowadays, they use IGZO,” Herman told Live Science. He presented his findings on April 4 at the national meeting of the American Chemical Society in San Francisco. In the study, the researchers made contact lenses that included transparent sheets of transistors made with IGZO. To test if the lenses could measure glucose levels, the transistors were coated with an enzyme called glucose oxidase, which breaks down sugar.