Navigation Links
Armchair science: DNA strands that select nanotubes are first step to a practical 'quantum wire'
Date:8/3/2011

DNA, a molecule famous for storing the genetic blueprints for all living things, can do other things as well. In a new paper,* researchers at the National Institute of Standards and Technology (NIST) describe how tailored single strands of DNA can be used to purify the highly desired "armchair" form of carbon nanotubes. Armchair-form single wall carbon nanotubes are needed to make "quantum wires" for low-loss, long distance electricity transmission and wiring.

Single-wall carbon nanotubes are usually about a nanometer in diameter, but they can be millions of nanometers in length. It's as if you took a one-atom-thick sheet of carbon atoms, arranged in a hexagonal pattern, and curled it into a cylinder, like rolling up a piece of chicken wire. If you've tried the latter, you know that there are many possibilities, depending on how carefully you match up the edges, from neat, perfectly matched rows of hexagons ringing the cylinder, to rows that wrap in spirals at various angles"chiralities" in chemist-speak.

Chirality plays an important role in nanotube properties. Most behave like semiconductors, but a few are metals. One special chiral formthe so-called "armchair carbon nanotube"**behaves like a pure metal and is the ideal quantum wire, according to NIST researcher Xiaomin Tu.

Armchair carbon nanotubes could revolutionize electric power systems, large and small, Tu says. Wires made from them are predicted to conduct electricity 10 times better than copper, with far less loss, at a sixth the weight. But researchers face two obstacles: producing totally pure starting samples of armchair nanotubes, and "cloning" them for mass production. The first challenge, as the authors note, has been "an elusive goal."

Separating one particular chirality of nanotube from all others starts with coating them to get them to disperse in solution, as, left to themselves, they'll clump together in a dark mass. A variety of materials have been used as dispersants, including polymers, proteins and DNA. The NIST trick is to select a DNA strand that has a particular affinity for the desired type of nanotube. In earlier work,*** team leader Ming Zheng and colleagues demonstrated DNA strands that could select for one of the semiconductor forms of carbon nanotubes, an easier target. In this new paper, the group describes how they methodically stepped through simple mutations of the semiconductor-friendly DNA to "evolve" a pattern that preferred the metallic armchair nanotubes instead.

"We believe that what happens is that, with the right nanotube, the DNA wraps helically around the tube," explains Constantine Khripin, "and the DNA nucleotide bases can connect with each other in a way similar to how they bond in double-stranded DNA." According to Zheng, "The DNA forms this tight barrel around the nanotube. I love this idea because it's kind of a lock and key. The armchair nanotube is a key that fits inside this DNA structureyou have this kind of molecular recognition."

Once the target nanotubes are enveloped with the DNA, standard chemistry techniques such as chromatography can be used to separate them from the mix with high efficiency.

"Now that we have these pure nanotube samples," says team member Angela Hight Walker, "we can probe the underlying physics of these materials to further understand their unique properties. As an example, some optical features once thought to be indicative of metallic carbon nanotubes are not present in these armchair samples."


'/>"/>

Contact: Michael Baum
michael.baum@nist.gov
301-975-2763
National Institute of Standards and Technology (NIST)
Source:Eurekalert  

Related biology technology :

1. Nomad Bioscience: New Plant Biotechnology Company Founded to Focus on Biomaterials and Biopharmaceuticals
2. Latest issue of Science: Nano-sonar uses electrons to measure under the surface
3. Latest issue of Science: Nanosonar uses electrons to measure under the surface
4. ROCK STARS OF SCIENCE: Pranas Co-Founding Scientist, Rudy Tanzi Teams up with Star-Powered Cast in GQ Photoshoot
5. MicuRx Pharmaceuticals Selects Next-Generation Antibiotic Candidate Targeting MRSA and Expands Operation in China
6. Valley Baptist Health System Selects Concuitys ClearContracts to More Accurately Calculate Payments from Managed Care and Government Payers
7. JD Technologies, LLC Selected by FCT Ingenieurkeramik GmbH to Represent Their High Performance Ceramic Expertise In the United States
8. Fujitsu PalmSecure and HT Systems PatientSecure Selected by BayCare Health System to Protect Patient Confidentiality and Prevent Medical Identity Theft
9. NEXCORE Technology Selected to Manufacture New Endoscopic Cryotherapy Device
10. Commonwealth Care Alliance Selects Casenet To Unify Patient Information and Improve Care for Massachusetts Members
11. Netsmart Technologies Selected by City and County of San Francisco to Provide Integrated Behavioral Healthcare Software System
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Armchair science: DNA strands that select nanotubes are first step to a practical 'quantum wire'
(Date:2/8/2016)... ... February 08, 2016 , ... Information Management Services ( ... The upgrade represents a completely new technical foundation and is so significant it ... responsive design interface, significantly increased speed for search results, a streamlined layout and a ...
(Date:2/8/2016)... -- Diplomat Pharmacy, Inc. (NYSE: DPLO) announced today that its new website has gone live. On Thursday, ... mobile-friendly. Visit the new site: www.diplomat.is ... ... ... "The goal was to reimagine the website and create ...
(Date:2/5/2016)... , Feb. 5, 2016  In the pharmaceutical industry ... a host of launch activities including the identification and ... launch activity is especially high in the oncology therapeutic ... Best Practices and the Role of Medical Affairs in ... focused on oncology therapies find better ways to utilize ...
(Date:2/4/2016)... - New FDA action date of July ... action date of July 22, 2016   --> ... 22, 2016   - Lifitegrast has the ... for the treatment of signs and symptoms of dry eye disease ... to be the only product approved in the U.S. in the past decade indicated for ...
Breaking Biology Technology:
(Date:2/2/2016)... Feb. 2, 2016  BioMEMS devices deployed ... focused on medical screening and diagnostic applications, ... Wearable devices that facilitate and assure continuous ... movement are being bolstered through new opportunities ... signal acquisition coupled with wireless connectivity and ...
(Date:2/2/2016)... , Feb. 2, 2016 Technology Enhancements Accelerate ... an analysis of the digital and computed radiography markets ... , and Indonesia (TIM). ... and market size, as well as regional market drivers ... and discusses market penetration and market attractiveness, both for ...
(Date:2/1/2016)... Rising sales of consumer electronics ... intuitive gesture control market size ... consumer electronics coupled with new technological advancements to drive ... through 2020   --> ... advancements to drive global touchfree intuitive gesture control market ...
Breaking Biology News(10 mins):