Bioelectrocatalysis by Microperoxidase‐11 in a Multilayer Architecture of Chitosan Embedded Gold Nanoparticles |
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| Authors: | Aysu Yarman Thomas Nagel Nenad Gajovic‐Eichelmann Anna Fischer Ulla Wollenberger Frieder W Scheller |
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| Institution: | 1. Fraunhofer Institute for Biomedical Engineering, D‐14476 Potsdam, Germany fax: (+)49?331?58187‐299;2. Institute of Chemistry, Technical University Berlin, 10623 Berlin, Germany;3. University of Potsdam, Institute of Biochemistry and Biology,Karl‐Liebknecht‐Str. 24–25, 14476 Golm, Germany |
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| Abstract: | We report on the redox behaviour of the microperoxidase‐11 (MP‐11) which has been electrostatically immobilized in a matrix of chitosan‐embedded gold nanoparticles on the surface of a glassy carbon electrode. MP‐11 contains a covalently bound heme c as the redox active group that exchanges electrons with the electrode via the gold nanoparticles. Electroactive surface concentration of MP‐11 at high scan rate is between 350±50 pmol cm?2, which reflects a multilayer process. The formal potential (E°′) of MP‐11 in the gold nanoparticles‐chitosan film was estimated to be ?(267.7±2.9) mV at pH 7.0. The heterogeneous electron transfer rate constant (ks) starts at 1.21 s?1 and levels off at 6.45 s?1 in the scan rate range from 0.1 to 2.0 V s?1. Oxidation and reduction of MP‐11 by hydrogen peroxide and superoxide, respectively have been coupled to the direct electron transfer of MP‐11. |
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| Keywords: | Microperoxidase Direct electron transfer Nanoparticles Hydrogen peroxide Superoxide Bioelectrocatalysis |
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