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Sensors 2013, 13(4), 5286-5301; doi:10.3390/s130405286
Article

Amperometric Immunosensor for Carbofuran Detection Based on MWCNTs/GS-PEI-Au and AuNPs-Antibody Conjugate

,
,
*  and *
School of Agriculture and Food Engineering, Shandong University of Technology, NO.12, Zhangzhou Road, Zibo 255049, China
* Authors to whom correspondence should be addressed.
Received: 28 February 2013 / Revised: 11 April 2013 / Accepted: 12 April 2013 / Published: 19 April 2013
(This article belongs to the Section Biosensors)
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Abstract

In this paper, an amperometric immunosensor for the detection of carbofuran was developed. Firstly, multiwall carbon nanotubes (MWCNTs) and graphene sheets-ethyleneimine polymer-Au (GS-PEI-Au) nanocomposites were modified onto the surface of a glass carbon electrode (GCE) via self-assembly. The nanocomposites can increase the surface area of the GCE to capture a large amount of antibody, as well as produce a synergistic effect in the electrochemical performance. Then the modified electrode was coated with gold nanoparticles-antibody conjugate (AuNPs-Ab) and blocked with BSA. The monoclonal antibody against carbofuran was covalently immobilized on the AuNPs with glutathione as a spacer arm. The morphologies of the GS-PEI-Au nanocomposites and the fabrication process of the immunosensor were characterized by X-ray diffraction (XRD), ultraviolet and visible absorption spectroscopy (UV-vis) and scanning electron microscopy (SEM), respectively. Under optimal conditions, the immunosensor showed a wide linear range, from 0.5 to 500 ng/mL, with a detection limit of 0.03 ng/mL (S/N = 3). The as-constructed immunosensor exhibited notable performance features such as high specificity, good reproducibility, acceptable stability and regeneration performance. The results are mainly due to the excellent properties of MWCNTs, GS-PEI-Au nanocomposites and the covalent immobilization of Ab with free hapten binding sites for further immunoreaction. It provides a new avenue for amperometric immunosensor fabrication.
Keywords: amperometric immunosensor; carbofuran; gold nanoparticles-antibody conjugation; multiwall carbon nanotubes; graphene sheets-PEI-Au nanocomposites amperometric immunosensor; carbofuran; gold nanoparticles-antibody conjugation; multiwall carbon nanotubes; graphene sheets-PEI-Au nanocomposites
This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).
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Zhu, Y.; Cao, Y.; Sun, X.; Wang, X. Amperometric Immunosensor for Carbofuran Detection Based on MWCNTs/GS-PEI-Au and AuNPs-Antibody Conjugate. Sensors 2013, 13, 5286-5301.

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