Diabetic patients typically check their blood glucose levels with a finger-prick blood test, or a subdermal implanted sensor. But an experimental new device could perform this function just sitting on the patient’s skin. Currently under development at Pennsylvania State University, the low-cost sensor is designed to measure glucose levels in the wearer’s sweat. Although the glucose concentration in sweat is about one one-hundredth as much as that in the bloodstream, there is a consistent correlation between the two.
The sensor incorporates a foam electrode, made up of laser-induced graphene coated with a nickel/gold alloy. Graphene is strong, chemically stable and electrically conductive, but it’s not glucose-sensitive, so nickel, which is very glucose-sensitive, is used in the electrode. The gold is added to reduce the risk of an allergic reaction to the nickel. In a test of the technology, the sensor was able to report levels in line with those obtained using a commercially available glucose monitor. Photo: Jia Zhu.