Wearable, Non-Invasive Sensor Measures Glucose in Sweat


Scientists at Penn State University developed a wearable glucose monitor that can non-invasively measure glucose levels within sweat in real time. The low-cost sensor consists of laser-induced graphene and a nickel-gold alloy that can detect the very low levels of glucose in sweat without the use of enzymes. The sensor contains a microfluidic chamber into which sweat is drawn, and then an alkaline solution reacts with the glucose in the sweat, causing a reaction in the alloy and a substantial electrical signal.

Measuring glucose levels is a pain, literally. From traditional finger stick tests to implantable monitors, there is an invasive element to the process. As patients with diabetes require frequent measurements of blood glucose levels, these invasive procedures are unavoidable, at least for now.

A pain-free alternative would involve exploiting a freely excreted body fluid that also contains glucose. This could provide a non-invasive alternative to blood glucose testing. The fluid is sweat, and while technology to reliably measure the tiny levels of glucose present in it is still not commercially available, researchers are hoping to change this.  

The Penn State research group is confident that the tiny levels of glucose found in sweat can provide a meaningful correlation with the amount found in the blood, and have designed a device to measure sweat glucose levels. The technology involves drawing sweat into a microfluidic chamber, where glucose reacts with an alkaline solution to form a compound that can react with a nickel-gold alloy present in the device. This reaction causes an electrical signal that can indicate the amount of glucose present in the sweat.

The device has numerous advantages over another sensor type, that requires enzymes to detect glucose. “An enzymatic sensor has to be kept at a certain temperature and pH, and the enzyme can’t be stored in the long term,” said Huanyu Cheng, a researcher involved in the study, in a press release. “A nonenzymatic glucose sensor, on the other hand, is advantageous in terms of stable performance and glucose sensitivity regardless of these changes.”

At only the size of a quarter, the device is unobtrusive. So far, the researchers have tested it with some volunteers, and found that it could successfully track changes in blood glucose before and after a meal.

“We want to work with physicians and other health care providers to see how we can apply this technology for daily monitoring of a patient,” said Cheng. “This glucose sensor serves as a foundational example to show that we can improve the detection of biomarkers in sweat at extremely low concentrations.”

See a video of someone wearing the sensor below:

Study in journal Biosensors and Bioelectronics: Laser-induced graphene non-enzymatic glucose sensors for on-body measurements

Via: Penn State

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