Nanoscale Palladium Metallization of DNA

W. Pompe1, M. Mertig1, J. Richter1, R. Seidel1, and H. K. Schackert2

1Institut für Werkstoffwissenschaft, Technische Universität Dresden, and 2Universitätsklinikum Carl Gustav Carus der Technischen Universität Dresden, D-01062 Dresden, Germany


We report on the fabrication of metallic nanowires by direct growth of palladium clusters on DNA. The metal deposition on the biomolecular template is accomplished in a two-step electroless metallization process. First, the DNA solution is treated with aquated metal salt complexes which in part adsorb on the DNA strands. Thereafter, the complexes are reduced to form metallic clusters. The kinetics of cluster growth is studied by UV-VIS spectroscopy. The functionalized DNA strands are examined by TEM and SFM.

In the initial stage of metal deposition separated Pd clusters with a size, comparable to the diameter of the DNA molecule, are formed on the template surface. Further deposition leads to a transition into a continuos, disordered metal film. The specific electrical conductivity of nanowires with diameters above 50 nm was measured to be only a factor of 10 smaller than bulk palladium.