A team from the Centre for Nanoparticle Research at the Institute for Basic Science (IBS) in South Korea has created a wearable GP-based patch that allows accurate diabetes monitoring by using human sweat.
The researchers improved the device’s detecting capabilities by integrating electrochemically active and soft functional materials on the hybrid of gold-doped graphene and a serpentine-shape gold mesh. The device’s pH and temperature monitoring functions enable systematic corrections of sweat glucose measurements as the enzyme-based glucose sensor is affected by pH (blood acidity levels) and temperature.
Type 2 diabetes affects around three million Koreans with the figure increasing due to dietary patterns and an ageing society. The current treatments are painful, inconvenient and costly; regular visits to a doctor and home testing kits are needed to record glucose levels. Patients also have to inject uncomfortable insulin shots to regulate glucose levels. There is a significant need for non-invasive, painless, and stress-free monitoring of important markers of diabetes using multifunctional wearable devices. The IBS device facilitates this and reduces the lengthy and expensive cycles of visiting doctors and pharmacies.
Kim Dae-Hyeong, one of the scientists, describes the components: 'Our wearable GP-based device is capable of not only sweat-based glucose and pH monitoring but also controlled transcutaneous drug delivery through temperature-responsive microneedles. Precise measurement of sweat glucose concentrations are used to estimate the levels of glucose in the blood of a patient. The device retains its original sensitivity after multiple uses, thereby allowing for multiple treatments. The connection of the device to a portable/ wireless power supply and data transmission unit enables the point-of-care treatment of diabetes.'
The patch is applied to the skin where sweat-based glucose monitoring begins on sweat generation. The humidity sensor monitors the increase in relative humidity (RH). It takes an average of 15 minutes for the sweat-uptake layer of the patch to collect sweat and reach a RH of over 80% at which time glucose and pH measurements are initiated.
Our wearable GP-based device is capable of not only sweat-based glucose and pH monitoring but also controlled transcutaneous drug delivery through temperature-responsive microneedles
Two healthy men participated in tests to demonstrate the sweat-based glucose sensing of the device. Glucose and pH levels of both subjects were recorded; a statistical analysis confirmed the reliable correlation between sweat glucose data from the diabetes patch and those from commercial glucose tests. If abnormally high levels of glucose are detected, a drug is released into a patient’s bloodstream via drug loaded microneedles. The malleable, semi-transparent skin-like appearance of the GP device provides easy and comfortable contact with human skin, allowing the sensors to remain unaffected by any skin deformations. This enables stable sensing and efficient drug delivery.
The scientific team also demonstrated the therapeutic effects by experimenting on diabetic (db/db) mice. Treatment began by applying the device near the abdomen of the db mouse. The group treated with microneedles showed a significant suppression of blood glucose concentrations compared with control groups.
'One can easily replace the used microneedles with new ones. Treatment with Metformin through the skin is more efficient than that through the digestive system because the drug is directly introduced into metabolic circulation through the skin,' said Kim Dae-Hyeong.
The research is published in the journal Nature Nanotechnology.
