A more convenient – and less painful – way to measure glucose Monitoring glucose levels requires diabetics to prick their fingers, which is both painful and inconvenient. But this may soon change, thanks to a new device that can measure glucose using tears instead of blood. Digital Economy Health © goffkein.pro, Shutterstock The key to managing diabetes is to constantly monitor blood glucose levels. For the billions of diabetics around the world, this means pricking their finger with a needle four or five times a day. Not only is this a painful procedure, it’s also a huge inconvenience. As a result, many diabetics simply fail to do the procedure as required – a failure that could put their lives at risk. What if there was a less painful and more convenient method for monitoring glucose? This is the question asked by the EU-funded GlucoTear project. “Our goal is to screen diabetes pathology without going through the painful finger-pricking procedure,” says Jesús Lancis, director of research and innovation, Optical Research Group, University Jaume I, the GlucoTear project’s lead partner. To accomplish this, the project has developed a solution that uses tears instead of blood and replaces the painful prick with a smartphone app. The research was undertaken with the support of the Marie Skłodowska-Curie Actions programme. Measuring glucose found in tears According to Lancis, the concentration of glucose found in tears is highly correlated with the glucose found in blood. “In theory, this means one can use tears to monitor ocular glucose as a marker for diabetes,” he explains. “The challenge, however, is that the concentration of glucose in tears is much lower than in blood.” To overcome this challenge, the project looked for a nanoparticle optical sensor that, when coupled with a smartphone camera, can be used to measure the concentration of glucose in a person’s tear. “With the GlucoTear solution, a diabetic patient will only need to collect a small amount of tears, mix it with a fluorescent substance, and place it under their smartphone’s camera,” adds Lancis. “By comparing the mixture’s level of fluorescence against a table of equivalences, the sensor will automatically read the glucose level.” The fluorescent substance is one of the project’s key innovations. It utilises carbon quantum dots (nanoparticles less than 5 nm in size), which have a fluorescent optical property. A biomarker with the tears of the diabetic is then attached to the interacting quantum dots. When illuminated with a blue light from the sensor, the mixture emits a fluorescent signal that allows one to measure the concentration of glucose in the sample. “The brighter the fluorescence, the higher the quantity of glucose in the sample,” notes Lancis. During testing, the GlucoTear solution proved able to sense glucose levels down to 1 mg/dL, which is within the range of glucose concentration found in such fluids as sweat and tears. Improving detection and treatment The GlucoTear solution is well-positioned to revolutionise how we treat and monitor diabetes. “Not only will it improve the quality of life of diabetics, it will also enable better detection of the disease, especially in developing countries,” concludes Lancis. “Furthermore, because everything is measured via mobile phones, all records can be kept digitally, thus reducing the risk of diagnostic or monitoring errors.” The project is currently working on optimising the solution’s biosensing. Following clinical trials, they aim to fully commercialise the GlucoTear solution. Keywords GlucoTear, glucose, diabetics, diabetes, carbon quantum dots
