DNA-Templated Construction of Copper Nanowires

We have developed a method to deposit Cu metal onto surface-attached DNA, forming nanowirelike structures that are ∼3 nm tall. DNA is first aligned on a silicon surface and then treated with aqueous Cu(NO3)2. After the copper(II) has electrostatically associated with the DNA, it is reduced by ascorbic acid to form a metallic copper sheath around the DNA. The resulting nanostructures have been observed and characterized by atomic force microscopy. A more complete coating can be obtained by repeating the Cu(II) and ascorbic acid treatment. Control experiments involving treatments with aqueous solutions containing either NO3- or the divalent cation Mg2+ show no change in DNA height upon ascorbic acid exposure. These experiments indicate that copper nanowires, which may be valuable as interconnects in nanoscale integrated circuitry, can be readily generated from DNA molecules on surfaces.