Complementary Chemistry and Matched Materials

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DNA linkers allow different kinds of nanoparticles to self-assemble and form relatively large-scale nanocomposite arrays.Photo courtesy of Brookhaven National Laboratory

DNA linkers allow different kinds of nanoparticles to self-assemble and form relatively large-scale nanocomposite arrays. This approach allows for mixing and matching components for the design of multifunctional materials.

DNA may be history's most successful matchmaker. And recently, researchers at the Office of Science's Brookhaven National Laboratory (Brookhaven Lab) coupled the complementary chemistry of DNA with some serious science savvy to create a new method for pairing up particles; a technique that may lead to the creation of many new materials with great potential.

DNA consists of four chemical bases which match up in pairs of A-T and G-C. The matches are complementary and quite specific – for instance, A only pairs with T, almost never C or G. The same is true for the others.

Brookhaven Lab researchers, led by physicist Oleg Gang in its Center for Functional Nanomaterials (CFN), used that precise pairing ability to match up materials in new and predictable ways. Namely, the team attached single strands of synthetic DNA to tiny particles (nanoparticles) of a few different substances – including gold with palladium, iron oxide and a couple of others – trying a variety of different pairings. Those DNA strands (linkers) could only pair up with their complements – for instance, a strand of A, G, G, T would only pair with a strand of T, C, C, A – which meant that the particles to which those strands were attached would also be precisely matched.

That technique allowed researchers to pair up even seemingly incompatible particles—for example, ones that might typically experience competing forces such as electrical or magnetic repulsion. The attractive force drawing complementary DNA strands together overcame the resistance, causing the particles to assemble themselves into large, three-dimensional lattices. This approach allowed researchers to build new materials with specificity and predictability, and altering the length of the DNA linkers also allowed researchers to control other properties of the new materials such as surface density.

As a consequence, the new technique might save researchers some of the errors of a typical scientific trial – especially those involved with the search for new materials. Even more importantly, as Dr. Gang said, "It offers routes for the fabrication of new materials with combined, enhanced, or even brand new functions."

For instance, researchers might use the method to develop new switches and sensors, which could be used in everything from chemical detectors to combustion engines. Scientists at Brookhaven Lab are already developing nanoparticles that could serve as better catalysts for hydrogen fuel vehicles and reduce the carbon monoxide emissions of more conventional conveyances. So the new technique could eventually lead to newer and even better catalysts, which might prove essential in other transportation technologies.

Ultimately, researchers at Brookhaven Lab – and those across the Office of Science – hope to solve the grand challenge of designing and then creating new forms of matter with precisely tailored properties. Will they succeed? Perhaps one day. Discovery and innovation is what they do: You might say it's in their DNA.

The Center for Functional Nanomaterials is one of five DOE Nanoscale Science Research Centers (NSRCs), national user facilities for interdisciplinary research at the nanoscale, supported by the DOE Office of Science. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE's Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos National Laboratories. For more information about the DOE NSRCs, please visit http://science.energy.gov.

The Department's Office of Science is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of the most pressing challenges of our time. For more information please visit http://science.energy.gov/about. For more information about Brookhaven Lab, please go to: http://www.bnl.gov/world/.

Charles Rousseaux is a Senior Writer in the Office of Science, [email protected].