An effective, non-invasive way of monitoring blood glucose could help both diabetics and those at risk of developing diabetes make the right choices to either manage the disease well, or reduce their risk of developing the condition. To address this need, an adhesive patch was developed that measures glucose levels through the skin without a finger-prick blood test, potentially removing the need for millions of diabetics to frequently carry out the painful and unpopular tests.
The patch does not pierce the skin. Instead, it draws glucose out from fluid between cells across hair follicles that are individually accessed via an array of miniature sensors using a small electric current. The glucose collects in tiny reservoirs and is measured. Readings can be taken every 10 to 15 minutes over several hours. Crucially, because of the design of the array of sensors and reservoirs, the patch does not require calibration with a blood sample, meaning that finger-prick blood tests are unnecessary.
The patch could eventually become a low-cost, wearable sensor that sends regular, clinically relevant glucose measurements to the wearer's phone or smart-watch wirelessly, alerting them when they may need to take action. An important advantage of this device over others is that each miniature sensor of the array can operate on a small area over an individual hair follicle. This significantly reduces inter- and intra-skin variability in glucose extraction, and increases the accuracy of the measurements taken such that calibration via a blood sample is not required.
The architecture of the array permits calibration-free operation, and has the further benefit of allowing realization with a variety of materials in combination. Graphene was used as one of the components, as it brings important advantages; specifically, it is strong, conductive, flexible, and potentially low-cost and environmentally friendly. In addition, the design can be implemented using high-throughput fabrication techniques like screen printing, which could support a disposable, widely affordable device.
The next steps include further refinement of the design of the patch to optimize the number of sensors in the array, to demonstrate full functionality over a 24-hour wear period, and to undertake a number of key clinical trials.