Researchers in the United States have developed prototype contact lenses that can change colour, which could one day replace the frequent skin prick test for diabetes patients needing to measure their blood sugar levels.
Scientists from the University of Akron have developed contact lenses that can detect glucose, the blood sugar present in our tears, sensing if the glucose is not being metabolised properly and if concentrations are building up. They can then alert the wearer of the problem by changing colour. As researcher Jun Hu points out “It works just like pH paper in your high school chemistry lab.”
The study involved using a probe molecule to bind to the sugars and mixed it with a dye, so that when sugar concentrations increase the sugar binds to the probe loosening the dye and resulting in a colour change to the lens.
Dr Hu added “This device could be used to detect subtle changes in blood sugar levels for tight management of diabetes. It can also be used to identify patients with pre-diabetic conditions, allowing early diagnosis that is crucial for preventing diabetes from advancing.”
However, the lens wearer won’t feel any difference when this happens unless they looked in a mirror, so the scientists are hoping to develop an app that can measure sugar levels from a camera phone picture.

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