Diabetes management might sometimes feel as though sufferers have, like Churchill, “nothing to offer but blood, toil, tears, and sweat.” However, by shifting monitoring from blood to sweat, an experimental technology may soon make life an awful lot easier and more pleasant for people with the disease.
The availability of artificial insulin for type 1 diabetes and drugs like metformin for type 2 mean that what was once a death sentence can now be treated. Unfortunately, to do this properly requires regular blood checks. That's not pleasant, particularly for younger children with type 1. If the gaps between samples get too long a dangerous, spikes in blood sugar levels may be missed. Continuous glucose monitoring devices exist, but have problems of their own.
A team at South Korea's Center for Nanoparticle Research has sought to address these challenges by measuring the glucose levels in sweat, rather than blood, preventing the need to pierce the skin. The idea isn't new, but a paper in Science Advances claims to have solved many of the previous problems.
By combining data from three glucose sensors, four pH measuring devices, and a humidity tracker on a wearable patch, Dr Hyuanjae Lee and colleagues have created a device they claim can provide an accurate indication of glucose levels. The multiple sensors mean the device's accuracy is not impaired by temperature or acidity changes that can otherwise disrupt the relationship between sugar concentrations in different bodily fluids.
The device was tested on human subjects, successfully demonstrating that its results correlate with blood glucose levels both before and after meals. Sweat pH levels vary by individual, so initial measurements must be calibrated against direct blood measurements for each wearer, but after this is done sweat measurements reduce, or possibly eliminate, the need for blood tests.
The same paper records a trial where mouse blood sugar levels were successfully controlled using real-time sweat monitoring to work out the appropriate drug dosages, delivered with microneedles.
The paper acknowledges that “for practical application of the current system there are several things to improve.” Sensors need greater long-term stability, and the correlations between sweat and blood measurements can be improved. Moreover, while the mouse testing was done only with metformin, a combination of fast and slow acting drugs could make for smoother responses to changing glucose levels.
Once these improvements are made, the authors believe the product will be ready for clinical trials to address the rising rates of diabetes worldwide. For diabetics in the future, there might be a lot fewer tears.
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