Gold Nanoparticles as Support for the Direct Electron Transfer and Catalysis of the Human Sulfite Oxidase

Stefano Frasca 1Oscar Rojas 1Johannes Salewski 2Inez M. Weidinger 2Silke Leimkuehler 1Joachim Koetz 1Ulla Wollenberger 1

1. University of Potsdam, Am Neuen Palais 10, Haus 19, Potsdam 14469, Germany
2. Berlin University of Technology, Hardenbergstr. 36, Berlin 10623, Germany

Abstract

We present the characterization of the direct electron transfer and the catalytic activity  of sulfite oxidase in a hybrid biosensor for sulfite detection, consisting of a combination of ultrafine gold nanoparticles and enzyme.

The human sulfite oxidase (hSOx) is a molybdenum and heme containing protein. It catalyzes the oxidation of sulfite to sulphate releasing the electrons to an external acceptor. The natural electron acceptor, cytochrome c, may be used to transfer electrons to an electrode [1]  or may be replaced by a chemically modified electrode [2]. On positively charged surfaces the electron transfer proceeds through the heme domain of sulfite oxidase. In order to increase the efficiency of the bioelectrocatalysis we introduced nanoparticles.   A hybrid system with an Au-electrode, self assembled alkyl thiol derivatives, polyethylene imine capped nanoparticles and sulfite oxidase has been created. The nanoparticles had a core size of about 6 ± 2 nm nm and a hydrodynamic diameter of 9 ± 1 nm.

Electrochemical as well as UV-vis and SERRS characterization of the system will be presented. hSOx_AuNPs.png
[1] Spricigo R., Dronov R., Rajagopalan K. V., Lisdat F., Leimkühler S., Scheller F. W., Wollenberger U. Soft Matter, 2008, 4, 972.

[2] Sezer M., Spricigo R., Utesch T., Millo D., Leimkühler S., Mroginski M. A., Wollenberger U., Hildebrandt P., Weidinger I. M. Phys Chem Chem Phys., 2010, 12, 7894-7903.

 

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Presentation: Short communication at SMCBS'2011 International Workshop, by Stefano Frasca
See On-line Journal of SMCBS'2011 International Workshop

Submitted: 2011-08-29 11:29
Revised:   2011-08-29 11:34