J Appl Phys 2013. in press 36. Subramanyam G, Heckman E, Grote J, Hopkins F: Microwave Selleck AZD6738 dielectric properties of DNA based polymers between 10 and 30 GHz. IEEE Microw Wireless Components Lett 2005, 15:232–234.CrossRef 37. Subramanyam G, Heckman E, Grote J, Hopkins F, Neidhard R, Nykiel E: Microwave dielectric properties of marine DNA based polymers. Microw Opt Technol Lett 2005, 46:278–282.CrossRef 38. Marssi ME, Marrec FL, Lukyanchuk IA, Karkut MG: Ferroelectric transition in an epitaxial barium titanate thin film: Raman spectroscopy and x-ray diffraction

study. J Appl Phys 2003, 94:3307–3312.CrossRef Competing interests The authors declare that they have no competing interests.

Authors’ contributions GC and CC designed and set up the experimental system. ML and CC planned the experiments. ML fabricated the films with the assistance of CM, GC, and JL. ADA and GS conducted this website the measurement of high-frequency microwave dielectric properties. YD and JC performed the electron microscopy studies. CD and YL performed the X-ray diffraction characterizations. MWC assisted in the data analysis. ML and CC wrote the manuscript. All authors read and approved the final manuscript.”
“Background The field of plasmonics has become a topic of major interest in the last years due to its property of showing an enhancement of the electromagnetic field at a sub-wavelength dimension [1]. This phenomenon is especially noticeable when there is plasmon coupling between metallic nanoparticles that are separated by nanometric gaps [2]. As a result of the overlap of the electromagnetic fields, there are near-field interactions that allow propagation

of light [3]. In this effort for designing plasmonic circuits by metal nanoparticle paths, the control of the location of the nanoparticles and the exact separation between them Selleck Rucaparib has been achieved, among other procedures, by means of biomolecular nanolithography using deoxyribonucleic acid (DNA) as scaffolds for the gold nanoparticles [4]. With this technique, the inter-particle separation is controlled by the ligand shell allowing angstrom-level precision [5]. To fully characterize such systems, electron energy loss spectroscopy (EELS) has demonstrated to be a very powerful tool since it can probe the local density of states for plasmonic nanoparticles [6], and it has the advantage over optical measurements that it provides information about bright and dark modes. In this work, we analyze the plasmonic properties of gold nanoparticles attached through DNA strands to a silicon nitride substrate. Individual nanoparticles as well as clusters of them were analyzed by EELS. Spectrum imaging (SI) maps are presented showing dark and bright plasmon modes in these assembled nanoparticles.