People with diabetes mellitus rely predominantly on finger pricking to measure blood levels of glucose, which can be onerous. A popular alternative is electrochemical microneedles used in continuous glucose monitors; however, these systems measure glucose levels in the interstitial fluid rather than in the blood directly, which potentially results in inaccurate measurements. A study in Nature Metabolism describes a new system for non-invasive measurement of blood levels of glucose using optoacoustic imaging.

The researchers tested the DIROS system in mice by measuring blood levels of glucose before and after a glucose tolerance test. Measurements were taken from the ear skin of the mice as well as the interstitial fluid, and validated with regular blood sampling. “Signals collected from within volumes rich in microvasculature related better to glucose concentrations than measurements from the interstitial fluid,” explain Ntziachristos, Pleitez and Uluç. Furthermore, Fourier-transform infrared spectroscopy measurements confirmed that there was a low chance of interference from other blood-based proteins and metabolites (such as lactate and albumin) when measured at physiological concentrations.