电化学-纳米金-辣根过氧化酶.pdfVIP

Sensors 2009, 9, 881-894; doi:10.3390/ OPEN ACCESS sensors ISSN 1424-8220 /journal/sensors Article Direct Electrochemistry of Horseradish Peroxidase-Gold Nanoparticles Conjugate * Gautham Kumar Ahirwal and Chanchal K. Mitra Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad, Andhra Pradesh, India 500 046. * Author to whom correspondence should be addressed; E-Mail: c_mitra@; Tel.: +91-40 Fax: +91-40145 Received: 27 November 2008; in revised form: 6 January 2009 / Accepted: 6 January 2009 / Published: 10 February 2009 Abstract: 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 H O , with good sensitivity and without any electron mediator. The 2 2 covalent linking of HRP and AuNP did not affect the activity of the enzyme significantly. The response of the electrode towards the