Researchers at Seoul National University in South Korea have made a new skin sensor that could make the lives of diabetics easier. The device was tested in a trial with 5 people aged between 20 and 60, and the results were published in the research paper Science Advances. The device is an armband that aims to allow diabetics to monitor their glucose levels in a more convenient way which is crucial in avoiding health issues arising from drops in blood sugar which can be very dangerous for this group.
Hyunjae Lee of the university said that the device “can surely contribute to improve the quality of life of diabetic patients.” He was the lead author of the paper. While the device is not ready for widespread release as of yet, it stands to revolutionize diabetic treatment since it relies on sweat measurement for calculation and monitoring as opposed to blood to track glucose levels in the system. Lee said of the progress that needs to be made: “The sensor should be more sensitive and reliable to enhance accuracy of sweat-based glucose monitoring system.” He continued:. “The correlation between sweat and blood glucose levels more thoroughly,” referring to what the device needs to improve on to deliver insulin accurately.
Current solutions that are the result of a large amount of research are more inconvenient and uncomfortable; most diabetics use finger pin prick devices to measure glucose, while newer devices can be implanted to the skin to act as an artificial pancreas to monitor glucose and then release insulin based on the readings as needed as a closed loop system.
These devices cause discomfort, but in the trial the new armband device was compared to the existing pinprick method one hour before and one hour after eating for each participant in the trial and the results showed that the armband device was comparable in accuracy to the needle method.
The device is applied to the user’s arm and maintains a waterproof connection with the skin, held in place with a band. The armband analyses sweat on the skin to measure moisture, acidity, glucose, and heat. The sensors in the device are made of flexible graphene and micro-amounts of gold in the electrodes. These sensors use electrical current detection to measure the variables mentioned above. Part of the surface generates low levels of heat to induce further sweating, and another part (measuring 1.5cm x 2cm) contains small needles that administer metformin. This drug is used for diabetes of the type 2 variety – insulin cannot be used yet in the device since its makeup has molecules that are too large to pass through the needles. It is hoped that future releases of the device will be able to use insulin.
Lee explained that “when blood glucose is high, [the] therapeutic part activates microneedle-based drug delivery.” After around a quarter of an hour of sweat detection on the sensors that look for acidity and glucose the device starts to take measurements. Lee also explained that it is designed to work with not much sweat which helps avoid people needing to exercise specifically for the task which many diabetics would prefer not to do. “Sweat generation through exercise could be a burden. Considering [that] point, we miniaturized sensor design that allows for reliable sweat analysis even with an infinitesimal amount of sweat.”
One part of the band also filters molecules with a negative charge, and also traces of medications that could give a false reading.
The team have not yet tested all of the functionality. Only the detection aspect has been trialled with humans, not the drug delivery aspect. They have, however used animal tests with mice. 16 mice with diabetes were tested by applying blue dye to their abdomens which were shaved and they were tested after being held in a fasted state for a night. Then the mice (ranging in age from 8 to 12 weeks old) had the device applied to the abdomen and a heating method was used to start the device functioning. The blue dye dispersal confirmed the administering of the drug metformin, and further confirmation was possible thanks to the positive reading of lower blood glucose six hours later compared to the control group. The heating method was used since there would not be enough sweat to start the device otherwise. As Lee explained: “In the animal experiment, we could confirm that blood glucose was continuously decreased and continued for six hours after microneedle therapy.”
More information can be found at: Seoul National University.