Pulse-Operated First-Generation Biosensors with Extended Linear Range for Continuous Glycemia Monitoring in...

We report on the Prussian Blue (PB) and glucose oxidase (GOx) based first-generation biosensor with a linear calibration range remarkably extended to high concentrations, which is suitable for continuous monitoring in oxygen-deficient media. The increase of the apparent Michaelis constant by several orders of magnitude, resulting in a record linear range, was achieved by reduction of the GOx amount immobilized in the sensor membrane. The latter allowed one to diminish the O₂ deficiency and keep its transport in pace with glucose oxidation. To compensate a predictable decrease in sensitivity, we suggested pulse power generation readout providing 100-fold response amplification. As a result, for the pulse-operated first-generation biosensors, the optimal linear range from 0.5 to 30 mM, high sensitivity (over 10 mA M^-1 cm^-2), extinguished dependence of the response on O₂ content, and improved operational stability were achieved. Such characteristics allowed the adaptation of the PB based biosensors for glycemia control upon continuous in vivo monitoring of the interstitial fluid glucose.