High electro-catalytic activities of glucose oxidase embedded one-dimensional ZnO nanostructures

Abstract

One-dimensional ZnO nanorods and nanowires are separately synthesized on Zn substrate by simple hydrothermal processes at low temperatures. Electro-catalytic responses of glucose oxidase/ZnO/Zn electrodes using these two synthesized nanostructures of ZnO are reported and compared with others available in literature. It is apparent the Michaelis-Menten constant, [Formula: see text], for the present ZnO nanowire, having a greater aspect ratio, is found to be the lowest when compared with others. This sensor shows lower oxidation peak potential with a long detection range of 6.6 μM-380 mM and the highest sensitivity of ∼35.1 μA cm(-2) mM(-1), among the reported values in the literature. Enzyme catalytic efficiency and turnover numbers are also found to be remarkably high.

Fabrication and Characterization of Glucose Biosensors by Using Hydrothermally Grown ZnO Nanorods

“…Considering the short distance between the morphological structure of nanorods and the active reaction site of enzyme, electrons tunnelled through ZnO even at low operating potential through DET. This observation agreed with that obtained by Nirmal and Swapan 32 . The fabricated electrode showed a high current in glucose detection because of the ZnO nanorod array which possessed high-aspect-ratio surface for GOx to immobilise onto and good alignment of ZnO nanorods for electron to transfer onto the substrate.…”

“…Adherence can be improved by growing nanorods directly on substrates rather than transferring loose nanorods onto substrates. Therefore, nanorod structure is ideal for enzyme immobilisation because it enables direct and fast electron transport between the electrode substrate and enzyme 32 . Nanorods grown directly on a substrate also provide good stability because the process is chemically and mechanically robust 33 .…”

Effect of immobilization technique on performance ZnO nanorods based enzymatic electrochemical glucose biosensor

“…In literature rf-sputtered ZnO thin films have been reported where sensitivity was obtained around 0.5-1.3 mA-cm -2 -M -1 [19]. Unlike this, ZnO nanostructures have been found to have improved sensitivities around 12-15 mA-cm -2 -M -1 [20].…”

A Highly Sensitive Nonenzymatic Glucose Sensor Based on Carbon Electrode Amplified with PdxCuy Catalyst

“…[2][3][4]. Because of the paramount importance and demand, a significant number of investigations based on enzymatic [5][6][7][8] sensing protocols have developed and commercialized, principally using the electrochemical oxidation procedure due to the possible advantages like high detection limit and sensitivity. But the procedure suffers from lack of enough selectivity due to interference effects [5].…”

“…A redox couple is typically used as a mediator to transfer the electron from the solution phase to the electrode at a relatively lower potential e. g. E 0 of ferricenium/ferrocene, potential redox couple = 0.39 V at 298.15 K in the second-generation sensor. A semiconduc-tor material like ZnO is used to send electrons from biocatalyst to metal, in the third-generation sensors [5] and works at a considerably lower potential (< 0.23 V for Zn/ZnO electrode). In the fourth-generation sensor, glucose sends electrons on oxidation directly to the metal [14,15] even at a more negative potential.…”