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.

Composite nanoparticle nanoslit arrays: a novel platform for LSPR mediated subwavelength optical transmission.

Near infrared transmission of light through subwavelength slit arrays is shown to be significantly influenced by resonant metallic nanoparticles placed within the structure. Experimental and calculated transmission spectra show how the size, orientation of the nanoparticles, and the period of the nanoslit array influence the maximum transmission wavelength, the magnitude of the transmission, and width of the resonance. These findings suggest that the localized surface plasmon resonance (LSPR) of metallic nanoparticles and their subsequent near and far-field interactions can modulate the subwavelength transmission and bandwidth of nanoaperture array devices in optically thick metal films.