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Mechanistic Studies of Fc-PNA(⋅DNA) Surface Dynamics Based on the Kinetics of Electron-Transfer Processes

Authors

  • Dr. Nina Hüsken,

    1. Inorganic Chemistry I, Bioinorganic Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum (Germany), Fax: (+49) 234-32-14378
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  • Dr. Magdalena Gębala,

    1. Analytische Chemie—Elektroanalytik & Sensorik and Centre for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum (Germany), Fax: (+49) 234-32-14683
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  • Dr. Fabio La Mantia,

    1. Analytische Chemie—Elektroanalytik & Sensorik and Centre for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum (Germany), Fax: (+49) 234-32-14683
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  • Prof. Dr. Wolfgang Schuhmann,

    Corresponding author
    1. Analytische Chemie—Elektroanalytik & Sensorik and Centre for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum (Germany), Fax: (+49) 234-32-14683
    • Analytische Chemie—Elektroanalytik & Sensorik and Centre for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum (Germany), Fax: (+49) 234-32-14683
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  • Prof. Dr. Nils Metzler-Nolte

    Corresponding author
    1. Inorganic Chemistry I, Bioinorganic Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum (Germany), Fax: (+49) 234-32-14378
    • Inorganic Chemistry I, Bioinorganic Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum (Germany), Fax: (+49) 234-32-14378
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Abstract

N-Terminally ferrocenylated and C-terminally gold-surface-grafted peptide nucleic acid (PNA) strands were exploited as unique tools for the electrochemical investigation of the strand dynamics of short PNA(⋅DNA) duplexes. On the basis of the quantitative analysis of the kinetics and the diffusional characteristics of the electron-transfer process, a nanoscopic view of the Fc-PNA(⋅DNA) surface dynamics was obtained. Loosely packed, surface-confined Fc-PNA single strands were found to render the charge-transfer process of the tethered Fc moiety diffusion-limited, whereas surfaces modified with Fc-PNA⋅DNA duplexes exhibited a charge-transfer process with characteristics between the two extremes of diffusion and surface limitation. The interplay between the inherent strand elasticity and effects exerted by the electric field are supposed to dictate the probability of a sufficient approach of the Fc head group to the electrode surface, as reflected in the measured values of the electron-transfer rate constant, k0. An in-depth understanding of the dynamics of surface-bound PNA and PNA⋅DNA strands is of utmost importance for the development of DNA biosensors using (Fc-)PNA recognition layers.

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