The increase in patients that have lifestyle diseases such as diabetes has become a worldwide problem that is not limited to Japan, which has entered an era of super-aging population. One effective means of preventing diabetes is to maintain the fluctuation of blood glucose level within an appropriate range. The instruments for measuring blood glucose level include self-monitoring blood glucose (SMBG) devices that measure a small amount of blood from a needle prick and continuous glucose monitoring (CGM) devices, which are medical instruments that measure blood from a needle that remains inserted for about 2 weeks. On the other hand, a noninvasive device that does not use needles to penetrate the body is desirable for visualizing metabolism and making appropriate recommendations as a simple and easy service.
Our objective is a wearable noninvasive measurement device that can continuously measure fluctuations in blood glucose level without needles. The device uses a photoacoustic measurement method that combines the advantages of the substance selectivity of light and the tissue transparency of sound.
Selective measurement of blood glucose is achieved by measuring the differences in multiple characteristic wavelengths of blood glucose and other components (water and others) using a continuous light source that is suitable for compact devices. We have fabricated a sensor interface that clamps onto an ear lobe to enable continuous and noninvasive measurement of changes in blood glucose level.