DNA directs nano-assembly: DNA used to direct nano-assembly. photo from wikimedia.

New nanoscale assembly technique

How can we assemble parts nearly a thousand times smaller than the width of a human hair? By using processes similar to those in Mother Nature, scientist are now constructing complex nanoassemblies. First we learned to produce nano-scaled parts like Buckyballs and carbon nanotubes(CNT). The next step in complexity is to connect some of these parts together in a particular way. Mother Nature does this using DNA. DNA contains code similar to a puzzle piece. It will only fit together with a correponding puzzle piece.

The Xu lab is the first in the world to make uniform arrays of carbon nanotubes. Lazareck and his collaborators at Brown and Boston College built on this platform to make their structures. They started with arrays of billions of carbon nanotubes of the same diameter and height evenly spaced on a base of aluminum oxide film. On the tips of the tubes, they introduced a tiny DNA snippet.
This synthetic snippet of DNA carries a sequence of 15 “letters” of genetic code. It was chosen because it attracts only one complement – another sequence made up of a different string of 15 “letters” of genetic code. This second sequence was coupled with a gold nanoparticle, which acted as a chemical delivery system of sorts, bringing the complementary sequences of DNA together. To make the wires, the team put the arrays in a furnace set at 600° C and added zinc arsenide. What grew: Zinc oxide wires measuring about 100-200 nanometers in length.
“We’re seeing the beginning of the next generation of nanomaterials,” said Xu, senior author of the article. Brown University Media Relations

The research team led by Brown University engineers has harnessed the coding power of DNA to create zinc oxide nanowires on top of carbon nanotube tips. The feat, detailed in the journal Nanotechnology, marks the first time that DNA has been used to direct the assembly and growth of complex nanowires. NanotechWire

Link to the paper published in the journal Nanotechnology