Glucose Nanosensor Based on Prussian-Blue Modified Carbon-Fiber Cone Nanoelectrode and an Integrated Reference Electrode

An enzyme nanosensor, based on a carbon fiber cone nanoelectrode modified by codeposition of Prussian blue (PB) and glucose oxidase (GOD), has been constructed. The nanosensor displays a low-potential electrocatalytic detection of the enzymatically liberated hydrogen peroxide, along with good reproducibility and high selectivity. The dependence of the nanosensor response upon parameters of the sensor preparation (e.g., amount of GOD, PB deposition time, Nafion coverage), and upon measurements conditions (e.g., pH, applied potential) was evaluated. An operating potential of –0.1 V (vs. Ag/AgCl) yielded the highest selectivity towards glucose, with no interference from ascorbic acid. The lifetime of the nanosensor is more than two weeks. Such miniaturization and analytical performance offer great promise for measurements of glucose in extremely small volumes.