three-dimensional structures using DNA-directed assembly.

Programming Advanced Materials

In 1996, scientists at IBM and Northwestern University used single-stranded DNA as if it were molecular Velcro to program the self-assembly of nanoparticles into simple structures. The work helped launch the then-nascent nanotechnology field by suggesting the possibility of building novel materials from the bottom up. Twelve years later, researchers from Northwestern and Brookhaven National Laboratory report separately in the journal Nature that they have finally delivered on that promise, using DNA linkers to transform nanoparticles into perfect crystals containing up to one million particles.

"The crystal structures are deliberately designed," says Northwestern's Chad Mirkin, one of the materials scientists who pioneered DNA linking in the 1990s and a coauthor of one of today's reports. "This is a new way of making things."

Ohio State University physicist David Stroud calls the work "quite valuable." He predicts that the breakthrough will enable the assembly of new materials with novel optical, electronic, or magnetic properties that have, until now, existed only in the minds and models of materials scientists. "Even now I'm surprised they could do it," says Stroud.

http://www.technologyreview.com/Nanotech/20137/