Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

DNA technique yields 3-D crystalline organization of nanoparticles

31.01.2008
First step toward 3-D catalytic, magnetic, and/or optical nanomaterials

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 techniques known for traditional crystals.

Importantly, they heat the samples of DNA-linked particles and then cool them back to room temperature. "This 'thermal processing' is somewhat similar to annealing used in forming more common crystals made from atoms," explained Nykypanchuk. "It allows the nanoparticles to unbind, reshuffle, and find more stable binding arrangements."

The team also experimented with different degrees of DNA flexibility, recognition sequences, and DNA designs in order to find a "sweet spot" of interactions where a stable, crystalline form would appear.

Results from a variety of analysis techniques, including small angle x-ray scattering at the National Synchrotron Light Source and dynamic light scattering and different types of optical spectroscopies and electron microscopy at the CFN, were combined to reveal the detail of the ordered structures and the underlying processes for their formation. These results indicate that the scientists have indeed found that sweet spot to create 3-D nanoparticle assemblies with long-range crystalline order using DNA. The crystals are remarkably open, with the nanoparticles themselves occupying only 5 percent of the crystal lattice volume, and DNA occupying another 5 percent. "This open structure leaves a lot of room for future modifications, including the incorporation of different nano-objects or biomolecules, which will lead to enhanced nanoscale properties and new classes of applications," said Maye. For example, pairing gold nanoparticles with other metals often improves catalytic activity. Additionally, the DNA linking molecules can be used as a kind of chemical scaffold for adding small molecules, polymers, or proteins.

Furthermore, once the crystal structure is set, it remains stable through repeated heating and cooling cycles, a feature important to many potential applications.

The crystals are also extraordinarily sensitive to thermal expansion - 100 times more sensitive than ordinary materials, probably due to the heat sensitivity of DNA. This significant thermal expansion could be a plus in controlling optical and magnetic properties, for example, which are strongly affected by changes in the distance between particles. The ability to effect large changes in these properties underlies many potential applications such as energy conversion and storage, as well as sensor technology.

The Brookhaven team worked with gold nanoparticles as a model, but they say the method can be applied to other nanoparticles as well. And they fully expect the technique could yield a wide array of crystalline phases with different types of 3-D lattices that could be tailored to particular functions.

"This work is the first step to demonstrate that it is possible to obtain ordered structures. But it opens so many avenues for researchers, and this is why it is so exciting," Gang says.

Karen McNulty Walsh | EurekAlert!
Further information:
http://www.bnl.gov
http://www.bnl.gov/newsroom

Further reports about: DNA Optical crystalline nanoparticle particles structure

More articles from Life Sciences:

nachricht A new technique isolates neuronal activity during memory consolidation
22.06.2017 | Spanish National Research Council (CSIC)

nachricht CWRU researchers find a chemical solution to shrink digital data storage
22.06.2017 | Case Western Reserve University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

Im Focus: Optoelectronic Inline Measurement – Accurate to the Nanometer

Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.

New Manufacturing Technologies for New Products

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

A new technique isolates neuronal activity during memory consolidation

22.06.2017 | Life Sciences

Plant inspiration could lead to flexible electronics

22.06.2017 | Materials Sciences

A rhodium-based catalyst for making organosilicon using less precious metal

22.06.2017 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>