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Sensors 2009, 9(2), 881-894;

Direct Electrochemistry of Horseradish Peroxidase-Gold Nanoparticles Conjugate

Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, Andhra Pradesh, 500 046 India
Author to whom correspondence should be addressed.
Received: 27 November 2008 / Revised: 6 January 2009 / Accepted: 6 January 2009 / Published: 10 February 2009
(This article belongs to the Section Chemical Sensors)
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We have studied the direct electrochemistry of horseradish peroxidase (HRP) coupled to gold nanoparticles (AuNP) using electrochemical techniques, which provide some insight in the application of biosensors as tools for diagnostics because HRP is widely used in clinical diagnostics kits. AuNP capped with (i) glutathione and (ii) lipoic acid was covalently linked to HRP. The immobilized HRP/AuNP conjugate showed characteristic redox peaks at a gold electrode. It displayed good electrocatalytic response to the reduction of H2O2, with good sensitivity and without any electron mediator. The covalent linking of HRP and AuNP did not affect the activity of the enzyme significantly. The response of the electrode towards the different concentrations of H2O2 showed the characteristics of Michaelis Menten enzyme kinetics with an optimum pH between 7.0 to 8.0. The preparation of the sensor involves single layer of enzyme, which can be carried out efficiently and is also highly reproducible when compared to other systems involving the layer-by-layer assembly, adsorption or encapsulation of the enzyme. The immobilized AuNP-HRP can be used for immunosensor applications View Full-Text
Keywords: Gold nanoparticles; glutathione; lipoic acid; horseradish peroxidase; and direct electron transfer Gold nanoparticles; glutathione; lipoic acid; horseradish peroxidase; and direct electron transfer

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This is an open access article distributed under the Creative Commons Attribution License (CC BY 3.0).

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Ahirwal, G.K.; Mitra, C.K. Direct Electrochemistry of Horseradish Peroxidase-Gold Nanoparticles Conjugate. Sensors 2009, 9, 881-894.

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