DNA technique yields 3-D crystalline organization of nan...( UPTON NY - In an achievement some se...)

UPTON, NY - In an achievement some see as the "holy grail" of nanoscience, researchers at the U.S. Department of Energy's Brookhaven National Laboratory have for the first time used DNA to guide the creation of three-dimensional, ordered, crystalline structures of nanoparticles (particles with dimensions measured in billionths of a meter). The ability to engineer such 3-D structures is essential to producing functional materials that take advantage of the unique properties that may exist at the nanoscale - for example, enhanced magnetism, improved catalytic activity, or new optical properties. The research will be published in the January 31, 2008, issue of the journal Nature.

"From previous research, we know that highly selective DNA binding can be used to program nanoparticle interactions," said Oleg Gang, a scientist at Brookhaven's Center for Functional Nanomaterials (CFN), who led the interdisciplinary research team, which includes Dmytro Nykypanchuk and Mathew Maye of the CFN, and Daniel van der Lelie of the Biology Department. "But while theory has intriguingly predicted that DNA can guide nanoparticles to form ordered, 3-D phases, no one has accomplished this experimentally, until now."

As with the group's previous work, the new assembly method relies on the attractive forces between complementary strands of DNA - the molecule made of pairing bases known by the letters A, T, G, and C that carries the genetic code of living things. First, the scientists attach to nanoparticles hair-like extensions of DNA with specific "recognition sequences" of complementary bases. Then they mix the DNA-covered particles in solution. When the recognition sequences find one another in solution, they bind together to link the nanoparticles.

This first binding is necessary, but not sufficient, to produce the organized structures the scientists are seeking. To achieve ordered crystals, the scientists alter the properties of DNA and borrow some tech
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