Zinc oxide nanorods biosensors based on electrochemical reaction for glucose sensing
Mohammed Marie and M O Manasreh
University of Arkansas, USA
: J Electr Eng Electron Technol
Abstract
Glucose biosensor based on zinc oxide ZnO nanorods was investigated. A sol – gel technique was used in the fabrication process and the working electrode was deposited on glass coated indium tin oxide with an area 0.3x0.3 cm2 . Zinc oxide nanorods were well aligned in a hexagonal structure with variety of diameters between 68 – 116.3 nm as it shown the scanning electron microscopy image. The Raman and absorbance spectroscopy were used to characterize the material. The absorbance optical peak was observed ~ 370 nm corresponding with the band gap of ZnO 3.37 eV and the measured was performed in the range from 300 – 1000 nm. The observed peak in Raman spectrum was at 440 cm-1 matching with the lattice vibration of ZnO. Glucose oxidase GOx and nafion membrane were spin coated with a speed 4000 rotation per minute on top of the nanorods to increase the sensitivity and prevent any undesired chemical reaction. The time response of the fabricated biosensor was 3 sec and the cyclic voltammetry curve illustrates the oxidation reduction process of glucose by GOx and the oxidation peak was around 0.5 V. The obtained sensitivity was 10.911 mA/mM cm2 and the lower limit of detection was 0.22 µM which indicates the high performance of the fabricated ZnO biosensor.
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