Micromachined biosensor system for interstitial fluid sampling and glucose monitoring

Continuous blood glucose monitoring is critically important for people with diabetes mellitus. In this paper, considering the long-term, flexible blood glucose monitoring demand, a biosensor system for interstitial fluid (ISF) ultrafiltration sampling and on-line monitoring of blood glucose is presented. The sensor system mainly consists of microfluidics base, silicon glucose sensor chip, and pressure supply module. It could harvest sufficient ISF quickly for glucose monitoring and discharge the used ISF after each measurement. The silicon glucose sensor chip is provided with diffusion control of the analyte through a porous silicon membrane into a silicon etched cavity containing the agarose immobilised enzyme. Experimental results show that the sensor system meets the needs of flexible ISF sampling, and its signal response time at increasing glucose concentrations is about 5s; The linear range is large enough to cover the required broad area of blood glucose (0.2 ~ 20 mmol/L), the sensitivity is 9.76 nA/mmol. L-1, and the correlation coefficient is 0.9954. This glucose sensor chip has better reliability and stability, and it is easier to integrate into the sensor system for ISF sampling and subsequent glucose monitoring.