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Impact of Single Basepair Mismatches on Electron-Transfer Processes at Fc-PNA⋅DNA Modified Gold Surfaces

Authors

  • Dr. Nina Hüsken,

    1. Inorganic Chemistry I, Bioinorganic Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum (Germany)
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  • Dr. Magdalena Gębala,

    1. Analytical Chemistry and Centre for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum (Germany)
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  • Alberto Battistel,

    1. Analytical Chemistry and Centre for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum (Germany)
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  • Dr. Fabio La Mantia,

    1. Analytical Chemistry and Centre for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum (Germany)
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  • Prof. Dr. Wolfgang Schuhmann,

    Corresponding author
    1. Analytical Chemistry and Centre for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum (Germany)
    • Analytical Chemistry and Centre for Electrochemical Sciences (CES), Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum (Germany)
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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)
    • Inorganic Chemistry I, Bioinorganic Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstrasse 150, 44801 Bochum (Germany)
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Abstract

Gold-surface grafted peptide nucleic acid (PNA) strands, which carry a redox-active ferrocene tag, present unique tools to electrochemically investigate their mechanical bending elasticity based on the kinetics of electron-transfer (ET) processes. A comparative study of the mechanical bending properties and the thermodynamic stability of a series of 12-mer Fc-PNA⋅DNA duplexes was carried out. A single basepair mismatch was integrated at all possible strand positions to provide nanoscopic insights into the physicochemical changes provoked by the presence of a single basepair mismatch with regard to its position within the strand. The ET processes at single mismatch Fc-PNA⋅DNA modified surfaces were found to proceed with increasing diffusion limitation and decreasing standard ET rate constants k0 when the single basepair mismatch was dislocated along the strand towards its free-dangling Fc-modified end. The observed ET characteristics are considered to be due to a punctual increase in the strand elasticity at the mismatch position. The kinetic mismatch discrimination with respect to the fully-complementary duplex presents a basis for an electrochemical DNA sensing strategy based on the Fc-PNA⋅DNA bending dynamics for loosely packed monolayers. In a general sense, the strand elasticity presents a further physicochemical property which is affected by a single basepair mismatch which may possibly be used as a basis for future DNA sensing concepts for the specific detection of single basepair mismatches.

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