A Single-Electrode, Dual-Potential Ferrocene–PNA Biosensor for the Detection of DNA

Authors

  • Nina Hüsken,

    1. Lehrstuhl für Anorganische Chemie I, Bioanorganische Chemie, Fakultät für Chemie und Biochemie, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801 Bochum (Germany), Fax: (+49) 234-32-14378
    Search for more papers by this author
  • Magdalena Gębala,

    1. Analytische Chemie, Elektroanalytik und Sensorik, Fakultät für Chemie und Biochemie, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801 Bochum (Germany)
    Search for more papers by this author
  • Wolfgang Schuhmann Prof. Dr.,

    1. Analytische Chemie, Elektroanalytik und Sensorik, Fakultät für Chemie und Biochemie, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801 Bochum (Germany)
    Search for more papers by this author
  • Nils Metzler-Nolte Prof. Dr.

    1. Lehrstuhl für Anorganische Chemie I, Bioanorganische Chemie, Fakultät für Chemie und Biochemie, Ruhr-Universität Bochum, Universitätsstrasse 150, 44801 Bochum (Germany), Fax: (+49) 234-32-14378
    Search for more papers by this author

Abstract

A Fc–PNA biosensor (Fc: ferrocenyl, C10H9Fe) was designed by using two electrochemically distinguishable recognition elements with different molecular information at a single electrode. Two Fc–PNA capture probes were therefore synthesized by N-terminal labeling different dodecamer PNA sequences with different ferrocene derivatives by click chemistry. Each of the two strands was thereby tethered with one specific ferrocene derivative. The two capture probes revealed quasi-reversible redox processes of the Fc0/+ redox couple with a significant difference in their electrochemical half-wave potentials of ΔE1/2=160 mV. A carefully designed biosensor interface, consisting of a ternary self-assembled monolayer (SAM) of the two C-terminal cysteine-tethered Fc–PNA capture probes and 6-mercaptohexanol, was electrochemically investigated by square wave (SWV) and cyclic voltammetry (CV). The biosensor properties of this interface were analyzed by studying the interaction with DNA sequences that were complementary to either of the two capture probes by SWV. Based on distinct changes in both peak current and potential, a parallel identification of these two DNA sequences was successful with one interface design. Moreover, the primary electrochemical response could be converted by a simple mathematical analysis into a clear-cut electrochemical signal about the hybridization event. The discrimination of single-nucleotide polymorphism (SNP) was proven with a chosen single-mismatch DNA sequence. Furthermore, experiments with crude bacterial RNA confirm the principal suitability of this dual-potential sensor under real-life conditions.

Ancillary