Tris(hydroxymethyl)phosphine-capped gold particles templated by DNA as nanowire precursors

Tris(hydroxymethyl)phosphine-capped gold nanoparticles (ca. 1-2 nm diameter) bind densely to DNA, although both species are negatively charged. The particles are also active catalysts for electroless plating of gold. Electroless plating after adsorption to calf thymus DNA immobilized on silicon provides nanowires as narrow as ca. 30-40 nm and electrical conductivities ca. one-thousandth that of bulk gold. Here we summarize our physical characterization of the particles and their DNA conjugates and initial electrical measurements after plating.