SiO2 coated Fe3O4 magnetic nanoparticle dispersed multiwalled carbon nanotubes based amperometric glucose biosensor.

A new type of amperometric glucose biosensor based on silicon dioxide coated magnetic nanoparticle decorated multiwalled carbon nanotubes (Fe(3)O(4)@SiO(2)/MWNTs) on a glassy carbon electrode (GCE) has been developed. MWNTs have been synthesized by catalytic chemical vapour decomposition (CCVD) of acetylene over rare earth (RE) based AB(3) alloy hydride catalyst. The as-grown MWNTs have been purified and further functionlized. Functionalized MWNTs have been decorated with magnetic Fe(3)O(4) nanoparticles which have been uniformly coated with biocompatible SiO(2) using a simple chemical reduction method. The characterization of magnetic nanoparticle modified MWNTs have been done by X-ray diffraction (XRD), Fourier transform infra red spectroscopy (FT-IR), scanning electron microscope (SEM), transmission electron microscope (TEM), vibrating sample magnetometer (VSM), energy dispersive X-ray analysis (EDX) and UV-vis spectroscopy. Amperometric biosensor has been fabricated by the deposition of glucose oxidase (GOD) over Nafion-solubilized Fe(3)O(4)@SiO(2)/MWNTs electrode. The resultant bioelectrode retains its biocatalytic activity and offers fast and sensitive glucose quantification. The performance of the biosensor has been studied using cyclic voltammetry and amperometry and the results have been discussed. The fabricated glucose biosensor exhibits a linear response from 1 microM to 30 mM with an excellent detection limit of 800 nM indicating the potential applications in food industries. Copyright (c) 2009 Elsevier B.V. All rights reserved.