Amperometric glucose biosensor based on glucose oxidase-lectin biospecific interaction

Abstract

An amperometric glucose biosensor based on high electrocatalytic activity of gold/platinum hybrid functionalized zinc oxide nanorods (Pt-Au@ZnONRs) and glucose oxidase (GOx)-lectin biospecific interaction was proposed. The Pt-Au@ZnONRs, which were prepared through a multiple-step chemosynthesis, were modified onto the surface of glassy carbon electrode (GCE) by a simple casting method due to the excellent film forming ability of the Pt-Au@ZnONRs suspension. Subsequently, a layer of porous gold nanocrystals (pAu) film was assembled onto the Pt-Au@ZnONRs film by immersing the electrode in HAuCl(4) solution to perform the electrochemical deposition at a constant potential of -0.2V. Following that, Concanavalin A (ConA) was immobilized onto the surface of pAu film through physical adsorption and covalent binding interactions between gold nanomaterials and the amino groups or thiol groups of ConA protein. Finally, the GOx was easily immobilized on the ConA/pAu/Pt-Au@ZnONRs/GCE by the biospecific interaction between GOx and ConA. The Pt-Au@ZnONRs composites were characterized using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Cyclic voltammetry (CV) was used to characterize the assembly process of the modified electrode. Proposed biosensor showed a high electrocatalytic activity to the glucose with a wide linear range covering from 1.8 μM to 5.15 mM, a low detection limit of 0.6 μM and a low apparent Michaelis-Menten constant (K(M)(app)) of 0.41 mM. Furthermore, the biosensor exhibited good reproducibility and long-term stability, as well as high selectivity. The integration of Pt-Au@ZnONRs and GOx-lectin biospecific interaction would offer potential promise for the fabrication of biosensors and biocatalysts.