Fastening azide-functionalised gold nanoparticles onto modified DNA holds great promise for nanoscale electrical circuits, say German researchers.

The trend for miniaturisation in electronics, and size and cost limitations of conventional lithographic techniques, has led researchers to develop alternative routes to nanoelectronic components.  DNA is a useful template for nanoscale electronic devices, explained Simon from the Institute for Inorganic Chemistry, Aachen, Germany, due to its well-defined structure and many electrostatic and chemical binding sites which can be modified.

Simon and colleagues have made a new type of gold nanoparticle containing an azide (-N₃) functional group.  They have coupled the nanoparticles to artificial DNA, where thymine bases are replaced by alkyne-modified derivatives, using a copper catalysed cycloaddition reaction.  This densely covers the DNA with nanoparticles at highly regular intervals.  As the nanoparticles can conduct electricity, the nanoparticle-modified DNA can potentially be used as a nanowire.

Monika Fischler, who also worked on the project, said that the 'major advantages [of this route] are the programmability of the DNA template through incorporating artificial bases, as well as the high selectivity and yield of the copper catalysed reaction.'

Duncan Graham of the University of Strathclyde, UK, praised the work.  He said that the 'formation of chains of nanoparticles is very challenging and this is a good approach to producing nanowires that potentially conduct electricity better.'

Vikki Chapman