Take a little DNA; add a pinch of carbon nanotubes; sprinkle in a few grains of gold, all on a clean silicon surface, and whip up a batch of nanotransistors – that’s pretty much what the research group of Prof. Ron Naaman of the Chemical Physics Department of the Weizmann Institute did. Only, they began with even more basic ingredients: tiny spoonfuls of phosphates, sugars and nucleotides that were used to create unique strands of DNA programmed to form attachments with carbon nanotubes.
Next, they used the same method to create another set of DNA strands that would hook up to miniscule electrical contacts made of gold that were anchored on the silicon surface. Afterwards, they added the first group of ingredients to the second and mixed well. The DNA strands fastened to the carbon nanotubes latched on to the strands attached to the gold contacts. The end result was a sort of carbon nanotube “bridge” spanning the silicon surface between two gold contacts.
Similar nanobridges between electrical contacts made of conducting materials such as gold may one day form the basis of tiny nanotransistors that will be used to build tiny, fast and efficient electronic circuits. In addition, the use of DNA may allow other biological molecules to be integrated into the circuit design that would interact with the DNA strands, thus modulating the behavior of the device. In their experiment, the results of which were published in Applied Physics Letters, the team managed to create nanotransistors with 10 percent of the available gold contact pairs, a figure they are currently working to improve.