Magnetic loading of carbon nanotube/nano-Fe3O4 composite for electrochemical sensing

An electrochemical sensing platform was developed based on the magnetic loading of carbon nanotube (CNT)/nano-FC3O4 composite on electrodes. To demonstrate the concept, nano-Fe3O4 was deposited by the chemical coprecipitation of Fe2+ and Fe3+ in the presence of CNTs in an alkaline solution. The resulting magnetic nanocomposite brings new capabilities for electrochemical devices by combining the advantages of CNT andnano-Fe3O4 andprovides an alternative way for loading CNT on electrodes. The fabrication and the performances of the magnetic nanocomposite modified electrodes have been described. Cyclic voltammetry (CV) and constant potential measurement indicated that the incorporated CNT exhibited higher electrocatalytic activity toward the redox processes of hydrogen peroxide. In addition, chitosan (CTS) has also been introduced into the bulk of the CNT/nano-Fe3O4 composite by coprecipitation to immobilize glucose oxidase (GOx) for sensing glucose. The marked electrocatalytic activity toward hydrogen peroxide permits effective low-potential amperometric biosensing of glucose, in connection with the incorporation of GOx into CNT/Fe3O4/CTS composite. The accelerated electron transfer is coupled with surface renewability. TEM images and XRDs offer insights into the nature of the magnetic composites. The concept of the magnetic loading of CNT nanocomposites indicates great promise for creating CNT-based biosensing devices and expands the scope of CNT-based electrochemical devices. (c) 2006 Elsevier B.V. All rights reserved.