Formation of gold particles on nanoscale toroidal DNA assembled with bis(ethylenediamine)gold(III)

DNA toroids formed by calf thymus DNA and trivalent cation bis(ethylenediamine)gold(III) are investigated using transmission electron microscopy and dynamic light scattering. Stable dispersions containing toroids with diameters of around 44 nm and thicknesses between 12 and 17 nm are readily prepared. These toroids are shown to be a robust platform for the preparation of metallic nanomaterials. Depending on the reaction conditions, the reduction of gold(III) in their presence can result in either toroids coated with many small (<10 nm) gold particles or larger continuous gold structures.