Oct. 17, 2006 — The speed of nanoparticle assembly can be accelerated with the assistance of DNA, a team of researchers at the U.S. Department of Energy’s Brookhaven National Laboratory in Upton, N.Y., recently found.
Nanoparticles could potentially be used for more efficient energy generation and data storage, as well as improved methods for diagnosing and treating disease. Learning how to control and tailor the assembly of nanoparticles into larger functional systems remains a major challenge for scientists. The Brookhaven results, published online on Oct. 11, 2006, by the Journal of the American Chemical Society, could be a step in that direction.
“Understanding how to self-assemble these types of nanomaterials has applications in all areas of nanotechnology, from optics to electronics to magnetic materials,” said the study’s lead author Mathew Maye, a Brookhaven chemist, in a prepared statement.
Maye is part of a team of interdisciplinary scientists from Brookhaven’s new Center for Functional Nanomaterials (CFN) and the biology department. The researchers found a way to control the assembly of gold nanoparticles using rigid, double-stranded DNA. Their technique takes advantage of this molecule’s natural tendency to pair up components called bases, known by the code letters A, T, G and C.
The synthetic DNA used in the laboratory is capped onto individual gold nanoparticles and customized to recognize and bind to complementary DNA located on other particles. The process forms clusters, or aggregates, of gold particles.
“It’s really by design,” Maye said. “We can sit down with a piece of paper, write out a DNA sequence, and control how these nanoparticles will assemble.”
One limitation to the assembly process is the use of single-stranded DNA, which can bend backward and attach to the particle’s gold surface instead of binding with surrounding nanoparticles. This flexibility, along with the existence of multiple forms of single-stranded DNA, can greatly slow the assembly process.
In the Brookhaven study, researchers introduced partially rigid, double-stranded DNA, which forces interacting linker segments of DNA to extend away from the gold surface, allowing for more efficient assembly. “By using properties of DNA, we can increase assembly kinetics, or speed, by relatively simple means without a lot of synthetic steps,” Maye said.