DNA creates self-assembling nano transistor

Proving it is possible to use biology to create electronics, scientists at the Technion-Israel Institute of Technology have harnessed the power of DNA to create a self-assembling nanoscale transistor, the building block of electronics.

Science has been intrigued with the idea of using biology to build electronic transistors that assemble without human manipulation.

To get the transistors to self-assemble, the research team attached a carbon nanotube "” known for its extraordinary electronic properties "” onto a specific site on a DNA strand and then made metal nanowires out of DNA molecules at each end of the nanotube.

The device is a transistor that can be switched on and off by applying voltage to it.

The carbon nanotubes used in the experiment are only one nanometre across. In computer technology, as scientists reach the limits of working with silicon, carbon nanotubes are recognised as the next step in squeezing an increasing number of transistors onto a chip, vastly increasing computer speed and memory.

However, computers are only one application; these transistors may, for example, enable the creation of any number of devices in future applications, such as tiny sensors to perform diagnostic tests in healthcare.

Though transistors made from carbon nanotubes have already been built, they required labour-intensive fabrication. The goal is to have these nanocircuits self-assemble, enabling large-scale manufacturing of nanoscale electronics.

While DNA by itself is a good self-assembling building block, it doesn't conduct electrical current.

To overcome this the researchers manipulated strands of DNA to add bacteria protein to a segment of the DNA. They then added certain protein molecules to the test tube, along with protein-coated carbon nanotubes.

These proteins naturally bond together, causing the carbon nanotube to bind to the DNA strand at the bacteria protein.

Finally, they created tiny meal nanowires by coating DNA molecules with gold. In this step, the bacteria protein served another purpose: it prevented the metal from coating the bacteria-coated DNA segment, creating extending gold nanowires only at the ends of the DNA strand.

At this point, the carbon nanotube is on a segment of DNA, with metal nanowires at either end. Theoretically, one challenge here would be to encourage the nanotube to line up parallel to the DNA strand, meet the nanowires at either end, and thus make a circuit.