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Measure glucose in sweat instead of blood

Many people in the world have diabetes. In the United States alone, the number rises to more than 34 million, by some estimates. Although the surveillance of blood glucose levels by the diabetes patient himself is essential to keep the disease at bay, pain and discomfort caused by the daily need to take blood samples by pricking a finger can cause people not to get tested as often as they should.

Juliane R. Sempionatto, Jong-Min Moon, and Joseph Wang, all from the University of California, San Diego, United States, have developed a handheld device that can measure glucose in sweat from your fingertip, a brief and gentle physical contact is enough. The device has a customizable algorithm for each individual that provides an accurate estimate of blood glucose levels.

Since the levels of this sugar are much lower in sweat than in blood, they can vary with a person’s sweat rate and the properties of their skin. As a result, the glucose level in sweat often does not accurately reflect the blood value. To get a more reliable estimate of blood sugar from sweat, Wang and his colleagues chose to devise a system that could collect sweat from a fingertip, measure glucose, and then correct for individual variability.

When the person places their fingertip on the sensor surface for one minute, a hydrogel absorbs small amounts of sweat. Inside the sensor, glucose from sweat undergoes an enzymatic reaction that results in a small electrical current detectable by a component of the device.

A pocket device combined with a tactile sweat sensor (strip to the right) measures glucose in sweat, while a custom algorithm converts that data into a blood glucose level value. (Image: Adapted from ACS Sensors 2021, DOI: 10.1021 / acssensors.1c00139)

In the tests carried out, the researchers also measured the blood sugar of the volunteers using the traditional method that requires the prick of the finger. From the information thus obtained, they developed a personalized algorithm that is capable of deducing the blood glucose levels of each person from the glucose levels of the sweat of each individual.

In tests, the algorithm was more than 95% accurate in predicting blood glucose levels before and after meals.

To keep the device well calibrated, the person with diabetes will need a finger stick only once or twice a month.

Although the results of the new system are very promising, before people with diabetes can start using it, a large-scale study must be carried out, as Wang, Sempionatto and Moon warn.

The creators of this system have published its technical details in the academic journal ACS Sensors, under the title “Touch-Based Fingertip Blood-Free Reliable Glucose Monitoring: Personalized Data Processing for Predicting Blood Glucose Concentrations”. (Source: NCYT from Amazings)

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