Resonant photoacoustic spectroscopy for a non-invasive blood glucose monitoring: human interface and temperature correction technology

Abstract

To prevent complications from diabetes mellitus, patients need to control their blood glucose levels by referencing the level measured with invasive needle pricks, which is stressful. As a principle for a non-invasive blood glucose monitoring method, we have proposed resonant photoacoustic spectroscopy (PAS), wherein two lights with different wavelengths are amplitude-modulated to linearize the PAS signal against glucose concentration. We have investigated the characteristics of resonant PAS using glucose aqueous solutions and have performed an in-vivo study of resonant PAS with healthy volunteers. For the in-vivo study, the resonant PAS interface was attached to the earlobe. Blood glucose levels were monitored by a commercially available sensor as a reference. To induce an increase in blood glucose levels, oral loading of glucose was applied to (healthy) volunteers based on the 2-h 75-g oral glucose tolerance test protocol. There was a correlation between the signal of resonant PAS and blood glucose levels in terms of the error grid, correlation coefficients between reference blood glucose levels, and mean absolute relative difference. The results show the potential of resonant PAS for non-invasive blood glucose monitoring.