Deprecated: mysql_connect(): The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead in /home2/nanodige/public_html/config.php on line 13
nano digest
 
X Close

Deprecated: mysql_connect(): The mysql extension is deprecated and will be removed in the future: use mysqli or PDO instead in /home2/nanodige/public_html/config.php on line 13
Untitled Document
 
I am delighted that Nano Digest has been doing great service to the nanoscience community by bringing out topical issues.

Prof C N R Rao, FRS
National Research Professor and , JNCASR
Read more...  
Quantum Science Symposium-2012
International Conference on Biotechnology and Nanotechnology (ICBN 2011)
Optics '11
Texas Instruments veteran Buss to lead forum on the future of electronics
nano tech 2013 - The12th International Nanotechnology Exhibition & Conference
More events...
Untitled Document
 
   News
Most Complex nanoparticles Designed
Sat, 04 Mar 2017

The most complex crystal designed and built from nanoparticles has been reported by researchers. The work demonstrates that some of nature`s most complicated structures can be deliberately assembled if researchers can control the shapes of the particles and the way they connect using DNA. Potential applications of the cage-like structures, called clathrates, include controlling light, capturing pollutants and delivering therapeutics. New types of lenses, lasers and even Star Trek-like cloaking materials are possible.

The most complex crystal designed and built from nanoparticles has been reported by researchers at Northwestern University and the University of Michigan. The work demonstrates that some of nature`s most complicated structures can be deliberately assembled if researchers can control the shapes of the particles and the way they connect using DNA.

"This is a tour de force demonstration of what is possible when one harnesses the chemistry of DNA and combines it with nanoparticles whose shapes encourage a particular crystal structure," said Chad A. Mirkin, the George B. Rathmann Professor of Chemistry in the Weinberg College of Arts and Sciences at Northwestern.

Nanotechnology promises to bring materials together in new ways, forging new capabilities by design. One potential application for crystals built of nanoparticles, such as these newly reported ones, is the control of light -- nanoparticles interact well with light waves because they are similar in size. This could lead to materials that can change colors or patterns on command or block certain wavelengths of light, while transmitting or amplifying others. New types of lenses, lasers and even Star Trek-like cloaking materials are possible.

"This work shows that nanoparticle crystals of extraordinary complexity are possible with DNA technology, once one begins to exploit particle shape," said Sharon C. Glotzer, the John W. Cahn Distinguished University Professor of Engineering and the Stuart W. Churchill Collegiate Professor of Chemical Engineering at U-M. "And, it`s a great example of what can be achieved by experimentalists and simulators teaming up."

The study, titled "Clathrate Colloidal Crystals," will be published March 3 in the journal Science. Mirkin and Glotzer are co-corresponding authors of the paper.

In chemistry, clathrates are known for their chambers that can house small molecules. They have been used for capturing pollutants from the environment, for example. The nanoparticle clusters also leave room for cargo, which the authors suggest could be useful for storing, delivering and sensing materials for environmental, medical diagnostic and therapeutic applications.

While natural materials exhibit a dizzying array of crystal structures, most nanotechnology labs struggle to get past simple designs. The structures produced by Haixin Lin, now a postdoctoral fellow in Mirkin`s lab, are far more interesting. The new structures are composed of clusters of up to 42 particles, forming larger polyhedral, such as the great dodecahedron. These clusters connect into cage-like crystal structures called clathrates.

Still, the story isn`t the crystal itself: it`s how the crystal came to be. Mirkin`s group has pioneered many structures through the use of DNA strands as a sort of smart glue, linking nanoparticles together in a particular way. The particle is both a building block and a template that directs bonding interactions. Meanwhile, Glotzer`s group has championed the role of nanoparticle shape in guiding the assembly of crystal structures through computer simulation.

"Chad`s group got the idea of exploring new phases by looking at predictions we had made," Glotzer said. "One day, I got a phone call from him. `We just got these incredible structures!` he said. And he texted me micrograph after micrograph -- they just kept popping up. He said, we need to figure out a way to definitively assign their structures."

The electron microscope images, or micrographs, showed complex crystalline structures that formed in large part thanks to the shape of the gold nanoparticles. The triangular bipyramidal shape, like two flattened tetrahedrons stuck together at their bases, was similar to a shape Glotzer`s group predicted would form a quasicrystal. Quasicrystals are prized in the field of nanoassembly because they are as complex as crystals get.

Lin`s shape had just the right angles to make clathrate structures, which often turn up in molecular systems that form quasicrystals. But to do so, they needed strands of DNA attached to their sides at just the right length.

Lin systematically made the gold bipyramids of consistent size and shape, with edge lengths of 250 nanometers -- half the wavelength of blue light. He then modified them with different length sequences of DNA. When the DNA strands were too short, the nanoparticles made disordered, ill-defined structures.

When longer strands produced exotic patterns in the electron microscope images, Lin brought the results to Mirkin, who was both thrilled and intrigued.

"These are stunning -- no one has made such structures before," said Mirkin, director of Northwestern`s International Institute for Nanotechnology.

It was clear they had made phases never observed before, but getting the structure accurately identified was essential. After Mirkin alerted Glotzer at U-M, Sangmin Lee and Michael Engel 3-D printed Lin`s bipyramids and glued them together to explore how they might make the structures in the electron micrographs. Lee is a doctoral student in chemical engineering, and Engel was then an assistant research scientist, both in Glotzer`s group.

Once they saw how the shapes fit together, they hypothesized the clathrate structures. To confirm their suspicions, they built a computer model of the hypothesized clathrates from bipyramids and compared it to the Northwestern micrographs. It was a perfect match.

As a definitive test, Lee and Matthew Spellings, also a doctoral student in chemical engineering at U-M, developed a molecular model of the DNA-linked nanoparticles. Lee carried out simulations to confirm that the particles would indeed form clathrate structures.

Courtesy: ScienceDaily

   
Other News
Water forms `Spine of Hydration` around DNA
Mass-Producible Quantum Computers
Nanoscale Examination of a Living Cell Membrane
Insulating Nanomagnets Driven by Spin Torque
Water is surprisingly ordered on the nanoscale
Math, Biology and Nanotechnology
Energy Decay in Graphene Resonators
First flat lens for immersion microscopy
Oddball Enzyme to Build new Biomaterials out of DNA
Self-healing Battery Anodes
Nano Fiber feels forces, hears sounds
First `Nanotherapeutics` Drug Delivered to a Tumor
Precision Control using Magnetic Molecules
Anticancer Nanomaterials
New Computer Chips
Stretchable Hologram
Beautiful, Consistent Carbon Belts
Nanoscale Imaging
Subatomic Scale
Wood filter
Slingshot
`Hot` electrons
More Wfficient Catalytic Material Developed
New material changes to the environment
Record Resolution at a nanometer length scale
Exotic nanomaterials
Nanoparticles explaining risks to heart
Nanodiamond-enhanced MRI
Nano-notch
Single-molecule diode created
A novel form of iron for fortification of foods
WALK-IN-INTERVIEWs
Bonding Chips using Inkjet Printers
Nanoparticles helps Melanoma Treatment
Imaging at the Speed of Light
Reusable Sponge that Soaks up Oil
Color-Changing Glass
Molecular `Leaf`
Optical Metamaterial
Low-Cost Diagnostic Systems
Ultralight Web of Silk Nano Fibers
shape-Shifting Molecular Robots
Magnetic `Persuasion` in Neighboring Metals
Anti-Fogging Water-Repellent Nanotextures
Portable Nanofiber
Resilient Flight Computers
Triboelectric nanogenerators
Nano `sandwich`
Computing with Biochemical Circuits made Easy
  Untitled Document
 
     
  Untitled Document
 
 
Untitled Document
  Follow us On  Follow us on FacebookFollow us on Twitter  
© 2010 Nano Digest. All Rights Reserved.   - Rify Hosting -