Portable, non-invasive sensor measures glucose in sweat

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

Measuring glucose levels is literally painful. From traditional finger samples to implantable screens, there is an invasive element in the process. As patients with diabetes require frequent measurements of blood glucose levels, these invasive procedures are unavoidable, at least for now.

A painless alternative would involve utilizing a freely excreted body fluid that also contains glucose. This may provide a non-invasive alternative to blood glucose testing. The fluid is sweaty, and although technology for reliably measuring the low glucose levels in it is still not commercially available, researchers hope to change this.

The Penn State research team is convinced that the small levels of glucose found in sweat can provide a meaningful correlation with the amount found in the blood, and has 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 may indicate the amount of glucose present in the sweat.

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

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

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

Watch a video of someone wearing the sensor below:

Studying in journal Biosensors and bioelectronics: Laser-induced graphene-non-enzymatic glucose sensors for body measurements

Via: Penn State

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