May 10, 2006
DNA directs growth of zinc oxide nanowires
While the idea of "bottom-up" self-assembly of functional nanomaterials has generated a great deal of excitement, it is difficult to achieve with the level of control required for the production of useful materials. The element that many precursors used for this purpose lack is the ability to program specific properties. "What is needed is a way to convey information or direct the assembling process at the nanometre scale," said Jimmy Xu of Brown University, US.
With that in mind, a team of engineers and chemists from Xu's laboratory and Shana Kelley's group at Boston College, US, worked together to investigate whether DNA-driven, self-assembly-based fabrication of nanostructures could be extended to build higher order materials. "We were curious to see if the coding scheme used in nature to program the human genome could be used to program the synthesis of materials and devices," said Kelley.
The researchers used DNA templating to position gold nanoparticle catalysts on the tips of carbon nanotubes. Then they grew zinc oxide nanowires on the catalyst particles, producing hybrid nanostructures.
Possible applications for such sequenced nanowires are molecular scale photoemitters and detectors. "If we were able to wire several together then even more complex devices are feasible," added Adam Lazareck of Brown University. "The next step is to measure the light detection capabilities of these structures. As the photocurrent generated is through a single carbon nanotube, this should be quite a challenging endeavour."