Enzymatic glucose biosensor based on ZnO nanorod array grown by hydrothermal decomposition

Abstract

We report herein a glucose biosensor based on glucose oxidase (GOx) immobilized on ZnO nanorod array grown by hydrothermal decomposition. In a phosphate buffer solution with a $p\mathrm{H}$ value of 7.4, negatively charged GOx was immobilized on positively charged ZnO nanorods through electrostatic interaction. At an applied potential of $+0.8\mathrm{V}$ versus $\mathrm{Ag}∕\mathrm{Ag}\mathrm{Cl}$ reference electrode, ZnO nanorods based biosensor presented a high and reproducible sensitivity of $23.1\mu \mathrm{A}{\mathrm{cm}}^{-2}{\mathrm{mM}}^{-1}$ with a response time of less than $5\mathrm{s}$ . The biosensor shows a linear range from $0.01\text{to}3.45\mathrm{mM}$ and an experiment limit of detection of $0.01\mathrm{mM}$ . An apparent Michaelis-Menten constant of $2.9\mathrm{mM}$ shows a high affinity between glucose and GOx immobilized on ZnO nanorods.