Researchers at the Institute for Basic Science in Seoul, Korea have developed an electronic skin patch capable of performing accurate glucose measurements while delivering insulin. The glucose sensor is based on gold-doped graphene and a gold mesh, and it corrects itself by using on-board pH and skin temperature sensors. Microneedles that can be controlled by changing their temperature are used to release insulin. The whole unit wirelessly interfaces with a nearby device to power it and to collect readings.
According to Kim Dae-Hyeong, a lead on the research, “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 over 80% at which time glucose and pH measurements are initiated.”
From the research study in Nature Nanotechnology:
Owing to its high carrier mobility, conductivity, flexibility and optical transparency, graphene is a versatile material in micro- and macroelectronics. However, the low density of electrochemically active defects in graphene synthesized by chemical vapour deposition limits its application in biosensing. Here, we show that graphene doped with gold and combined with a gold mesh has improved electrochemical activity over bare graphene, sufficient to form a wearable patch for sweat-based diabetes monitoring and feedback therapy. The stretchable device features a serpentine bilayer of gold mesh and gold-doped graphene that forms an efficient electrochemical interface for the stable transfer of electrical signals. The patch consists of a heater, temperature, humidity, glucose and pH sensors and polymeric microneedles that can be thermally activated to deliver drugs transcutaneously. We show that the patch can be thermally actuated to deliver Metformin and reduce blood glucose levels in diabetic mice.