Mice Glucose Level Monitoring by a Non-Invasive Microwave Imaging Technique

This study presents a new in-vivo microwave imaging method to determine the blood glucose levels of mice directly from their tail using a thermo-elastic optical indicator microscope (TEOIM). By measuring the microwave near-field distribution intensity around the tail, the changing trend of the glucose level can be detected non-invasively when the mouse tail is exposed to 7 GHz microwave irradiation. The microwave electric field distribution was visualized by the metasurface-based optical indicator, showing that the average intensity values are proportional to the blood glucose levels. The clinical accuracy of TEOIM glucose monitoring systems was evaluated using the Clarke error grid (CEG) analysis method, where 100% of the measurement points were in the A + B zone of the CEG. Based on the experimental results, the TEOIM can adequately detect the blood glucose concentration in the 170-500 mg/dL range. The testing results achieve a mean absolute relative difference (MARD) of 7.05% for the measurement and a root mean squared error (RMSE) of 24.85 mg/dL. The potential improvement methods of the imaging system for non-invasive glucose measurement were discussed, emphasizing future research plans to enhance accuracy and validation, which may positively impact healthcare and diabetes screening. This method provides a novel approach for the non-invasive sensing of blood glucose concentrations in-vivo using a CCD sensor.