The 4" diameter chip is roughly the
same thickness as the Canadian one
dollar coin;© American Institute of

Now Paul Li and colleagues at Simon Fraser University in Burnaby, Canada have combined DNA microarrays with microfluidic devices, which are used for the precise control of liquids at the nanoscale.

In an upcoming publication, Li and his colleagues describe how the first combined device can be used for probing and detecting DNA.

The key to Li's result: gold nanoparticles. Suspended in liquid and mixed with DNA, the nanometer-scale spheres of gold act as mini magnets that adhere to each of the DNA's twin strands. When the DNA is heated, the two strands separate, and the gold nanoparticles keep them apart, which allows the single strands to be probed with other pieces of DNA that are engineered to recognize particular sequences.

"It's faster and requires a relatively small sample," he says, adding in his paper that "the whole procedure is accomplished at room temperature in an hour and apparatus for high temperature… is not required"; Source: American Institute of Physics