A numerical analysis of continuous glucose monitoring method using a microdialysis technique

Monitoring of subcutaneous tissue glucose concentration is an attractive tool to detect a continuous glucose concentration, and has been studied by several researchers. We have proposed a new method, which can measure the concentration of subcutaneous tissue continuously, even when the recovery rate and the biosensor output current decreased. Two reference solutions were prepared with concentrations above and below the object concentration. These were perfused alternately with the same ratio of two periods. The output detected at the sensor, multiplied by the constant gain, was provided as feedback to the ratio. The glucose concentration in the subcutaneous tissue was calculated using the ratio of the two perfusion periods. To analyze the diffusion between the microdialysis probe and subcutaneous tissue, a compartment model was established. The numerical study was performed with a compartment model and control theory. In the simulation, the 90% response time to step change was about 7 min, which is fast enough when compared with the sharp fluctuations of a blood glucose level. This result suggested that our method was effective.