A comprehensive review of glucose biosensors based on nanostructured metal-oxides

Abstract

Nanotechnology has opened new and exhilarating opportunities for exploring glucose biosensing applications of the newly prepared nanostructured materials. Nanostructured metal-oxides have been extensively explored to develop biosensors with high sensitivity, fast response times, and stability for the determination of glucose by electrochemical oxidation. This article concentrates mainly on the development of different nanostructured metal-oxide [such as ZnO, Cu(I)/(II) oxides, MnO(2), TiO(2), CeO(2), SiO(2), ZrO(2,) and other metal-oxides] based glucose biosensors. Additionally, we devote our attention to the operating principles (i.e., potentiometric, amperometric, impedimetric and conductometric) of these nanostructured metal-oxide based glucose sensors. Finally, this review concludes with a personal prospective and some challenges of these nanoscaled sensors.

Keywords: electrochemical principles; enzymatic sensor; glucose biosensor; nanostructured metal-oxides; nonenzymatic sensor.

Figure 1.

Schematic illustration of the configuration of the MOSFET-based potentiometric glucose detection using an extended-gate functionalized-ZnO nanowire as a working electrode and the Ag/AgCl reference electrode (reproduced with permission from [54]. Copyright 2009, IEEE).

Figure 2.

(A) A schematic illustration of the first generation and (B) the second generation amperometric glucose sensors (redrawn from reference [61]).

Figure 3.

Schematic illustration of the preparation of the third generation amperometric glucose sensor based on the GOx-immobilized aligned ZnO nanorod (redrawn from reference [69]).

Figure 4.

(a) Scanning electron microscope (SEM) image of the ZnO nanotube arrays; the energy dispersive X-ray spectroscopy (EDS) analysis (inset). (b) SEM image of the surface modified ZnO nanotube arrays; the EDS analysis (inset). (c) Typical amperometric response curve of GOx/ZnO nanotube arrays/ITO electrodes with the glucose concentration increases in 10 μM per step by successive addition of glucose to the 0.02 M phosphate buffer solution (PBS) at pH 7.4 under stirring. The applied potential was +0.8 V vs. SCE (reproduced with permission from [83]. Copyright 2009, The American Chemical Society).

Figure 5.

Reaction mechanism of glucose at a MnO₂/GOx modified SPE based on heterogeneous carbon material: (i) enzymatic oxidation of glucose by GOx, (ii) chemical oxidation of H₂O₂, and (iii) chemical reduction of H₂O₂ (redrawn from reference [133]).

Figure 6.

Schematic illustration of two possible biochemical reaction mechanisms on the GOx/CeO₂/Pt electrode (redrawn from reference [176]).