Synthesis of magnetic nanoparticles composed by Prussian blue and glucose oxidase for preparing highly sensitive and selective glucose biosensor

A novel glucose biosensor was prepared with Fe3O4 nanoparticles containing Prussian blue (PB) and glucose oxidase (GOD) attracted to the surface of solid paraffin carbon paste electrode by magnetic force. The prepared Fe3O4/PB composite nanoparticles were about 50 nm in diameter and the glucose oxidase was covalently conjugated to the amine-modified nanoparticles. Because of the high reactivity of hydrogen peroxide with Prussian blue contained in the glucose biosensor, the hydrogen peroxide formed during the enzymatic reaction with glucose was measured by the current generated to determine the glucose concentration. The biosensor showed high sensitivity, selectivity, stability and short response time. It exhibited a linear response to glucose over the range from 5.0 × 10−7 to 8.0 × 10−5 M with a detection limit of 1.0 × 10−7 M. The apparent Michaelis–Menten constant Km was found to be 1.44 × 10−5 M. Reductive substances in biological samples did not interfere with the detection of glucose. The biosensor was also used to determine the glucose concentration in human blood samples.