Charge Transfer through Modified Peptide Nucleic Acids

We studied the charge transfer properties of bipyridine-modified peptide nucleic acid (PNA) in the absence and presence of Zn­(II). Characterization of the PNA in solution showed that Zn­(II) interacts with the bipyridine ligands, but the stability of the duplexes was not affected significantly by the binding of Zn­(II). The charge transfer properties of these molecules were examined by electrochemistry for self-assembled monolayers of ferrocene-terminated PNAs and by conductive probe atomic force microscopy for cysteine-terminated PNAs. Both electrochemical and single molecular studies showed that the bipyridine modification and Zn­(II) binding do not affect significantly the charge transfer of the PNA duplexes