Relationship between surface morphology and performance of a spirally hierarchical structure-based electrochemical glucose sensor

A spirally hierarchical structure-based glucose enzymatic electrode was prepared in the experiment on the basis of that zinc oxide nanowires were hydrothermally synthesized on the surface of an Au cylindrical spiral formed by manually winding an Au fiber around an optical fiber core, and then glucose oxidase was immobilized on these nanowires by physical adsorption. The surface morphologies of the spirally hierarchical structures and corresponding enzymatic electrodes were extracted, and the electrochemical performances of the enzymatic electrodes were characterized. The results indicated that the synthesizing parameters of zinc oxide nanowires affected significantly the surface morphologies of the glucose oxidase immobilization on the spirally hierarchical structures, and the performances of related glucose sensors. As the Zn²⁺ concentration of growth solution was set at 25 mM, the surface morphology was determined as roughness to be 0.10 μm and correlation length 0.29 μm, resulting in a better immobilization of glucose oxidase upon zinc oxide nanowires. In this case, the sensitivity of the glucose sensor was determined to be 2.15 μA mM^-1 cm^-2, the linear range was 0-4.50 mM, the low detection limit was 9.20 μM and Michaelis-Menten constant was 3.68 mM. The results not only benefited the batch production of the spirally hierarchical structure-based enzymatic electrodes, but also significantly improved the performances of the glucose sensors.