Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists use nanoscale building blocks and DNA 'glue' to shape 3-D superlattices

23.04.2015

New approach to designing ordered composite materials for possible energy applications

Taking child's play with building blocks to a whole new level-the nanometer scale-scientists at the U.S. Department of Energy's (DOE) Brookhaven National Laboratory have constructed 3D "superlattice" multicomponent nanoparticle arrays where the arrangement of particles is driven by the shape of the tiny building blocks.


Controlling the self-assembly of nanoparticles into superlattices is an important approach to build functional materials. The Brookhaven team used nanosized building blocks -- cubes or octahedrons -- decorated with DNA tethers to coordinate the assembly of spherical nanoparticles coated with complementary DNA strands.

Credit: Brookhaven National Laboratory

The method uses linker molecules made of complementary strands of DNA to overcome the blocks' tendency to pack together in a way that would separate differently shaped components. The results, published in Nature Communications, are an important step on the path toward designing predictable composite materials for applications in catalysis, other energy technologies, and medicine.

"If we want to take advantage of the promising properties of nanoparticles, we need to be able to reliably incorporate them into larger-scale composite materials for real-world applications," explained Brookhaven physicist Oleg Gang, who led the research at Brookhaven's Center for Functional Nanomaterials (CFN), a DOE Office of Science User Facility.

"Our work describes a new way to fabricate structured composite materials using directional bindings of shaped particles for predictable assembly," said Fang Lu, the lead author of the publication.

The research builds on the team's experience linking nanoparticles together using strands of synthetic DNA. Like the molecule that carries the genetic code of living things, these synthetic strands have complementary bases known by the genetic code letters G, C, T, and A, which bind to one another in only one way (G to C; T to A). Gang has previously used complementary DNA tethers attached to nanoparticles to guide the assembly of a range of arrays and structures. The new work explores particle shape as a means of controlling the directionality of these interactions to achieve long-range order in large-scale assemblies and clusters.

Spherical particles, Gang explained, normally pack together to minimize free volume. DNA linkers-using complementary strands to attract particles, or non-complementary strands to keep particles apart-can alter that packing to some degree to achieve different arrangements. For example, scientists have experimented with placing complementary linker strands in strategic locations on the spheres to get the particles to line up and bind in a particular way. But it's not so easy to make nanospheres with precisely placed linker strands.

"We explored an alternate idea: the introduction of shaped nanoscale 'blocks' decorated with DNA tethers on each facet to control the directional binding of spheres with complementary DNA tethers," Gang said.

When the scientists mixed nanocubes coated with DNA tethers on all six sides with nanospheres of approximately the same size, which had been coated with complementary tethers, these two differently shaped particles did not segregate as would have been expected based on their normal packing behavior. Instead, the DNA "glue" prevented the separation by providing an attractive force between the flat facets of the blocks and the tethers on the spheres, as well as a repulsive force between the non-pairing tethers on same-shaped objects.

"The DNA permits us to enforce rules: spheres attract cubes (mutually); spheres do not attract spheres; and cubes do not attract cubes," Gang said. "This breaks the conventional packing tendency and allows for the system to self-assemble into an alternating array of cubes and spheres, where each cube is surrounded by six spheres (one to a face) and each sphere is surrounded by six cubes." Using octahedral blocks instead of cubes achieved a different arrangement, with one sphere binding to each of the blocks' eight triangular facets.

The method required some thermal processing to achieve the most uniform long-range order. And experiments with different types of DNA tethers showed that having flexible DNA strands was essential to accommodate the pairing of differently shaped particles.

"The flexible DNA shells 'soften' the particles, which allows them to fit into arrangements where the shapes do not match geometrically," Lu said. But excessive softness results in unnecessary particle freedom, which can ruin a perfect lattice, she added. Finding the ideal flexibility for the tethers was an essential part of the work.

The scientists used transmission and scanning electron microscopy at the CFN and also conducted x-ray scattering experiments at the National Synchrotron Light Source, another DOE Office of Science User Facility at Brookhaven Lab, to reveal the structure and take images of assembled clusters and lattices at various length scales. They also explained the experimental results with models based on the estimation of nanoscale interactions between the tiny building blocks.

"Ultimately, this work shows that large-scale binary lattices can be formed in a predictable manner using this approach," Gang said. "Given that our approach does not depend on the particular particle's material and the large variety of particle shapes available-many more than in a child's building block play set-we have the potential to create many diverse types of new nanomaterials."

###

This research and operations at CFN and NSLS were funded by the DOE Office of Science.

Brookhaven National Laboratory is supported by the Office of Science of the U.S. Department of Energy. The 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 science.energy.gov.

One of ten national laboratories overseen and primarily funded by the Office of Science of the U.S. Department of Energy (DOE), Brookhaven National Laboratory conducts research in the physical, biomedical, and environmental sciences, as well as in energy technologies and national security. Brookhaven Lab also builds and operates major scientific facilities available to university, industry and government researchers. Brookhaven is operated and managed for DOE's Office of Science by Brookhaven Science Associates, a limited-liability company founded by the Research Foundation for the State University of New York on behalf of Stony Brook University, the largest academic user of Laboratory facilities, and Battelle, a nonprofit applied science and technology organization.

Media Contact

Karen McNulty Walsh
kmcnulty@bnl.gov
631-344-8350

 @brookhavenlab

http://www.bnl.gov 

Karen McNulty Walsh | EurekAlert!

More articles from Materials Sciences:

nachricht Researchers devise microreactor to study formation of methane hydrate
23.08.2017 | NYU Tandon School of Engineering

nachricht Meter-sized single-crystal graphene growth becomes possible
22.08.2017 | Science China Press

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

What the world's tiniest 'monster truck' reveals

23.08.2017 | Life Sciences

Treating arthritis with algae

23.08.2017 | Life Sciences

Witnessing turbulent motion in the atmosphere of a distant star

23.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>