Navigation Links
Nano parfait a treat for scientists

In two new papers, Rice University researchers report using ultracentrifugation (UCF) to create highly purified samples of carbon nanotube species.

One team, led by Rice Professor Junichiro Kono and graduate students Erik Haroz and William Rice, has made a small but significant step toward the dream of an efficient nationwide electrical grid that depends on highly conductive quantum nanowire.

The other, led by Rice Professor Bruce Weisman and graduate student Saunab Ghosh, employed UCF to prepare structurally sorted batches of semiconducting nanotubes that could find critical uses in medicine and electronics.

UCF is what it sounds like: a super-fast version of the centrifuge process medical lab technicians use to separate blood cells from plasma.

The process involves suspending mixtures of single-walled carbon nanotubes in combinations of liquids of different densities. When spun by a centrifuge at up to 250,000 g that's 250,000 times the force of gravity the nanotubes migrate to the liquids that match their own particular densities. After several hours in the centrifuge, the test tube becomes a colorful parfait with layers of purified nanotubes. Each species has its own electronic and optical characteristics, all of which are useful in various ways.

Weisman's lab reported its results in today's online edition of Nature Nanotechnology. Weisman is a professor of chemistry at Rice.

Kono's lab reported its results recently in the online edition of ACS Nano. Kono is a professor in electrical and computer engineering and professor of physics and astronomy.

The lack of pure batches of nanotubes species "has been a real hindrance in the field for nearly 20 years," Weisman said. While the UCF technique is not new, Ghosh found careful fine-tuning of the gradient structure let him sort at least 10 of the numerous species of nanotubes contained in a single sample produced by the Rice-created HiPco process.

Basic research is a big early winner, "because when you can get pure samples of nanotubes, you can learn so much more about them," Weisman said. "Secondly, some electronic applications become much simpler because the tube type determines the nanotube's band gap, a crucial electronic property." Biomedical applications may benefit by exploiting the optical properties of specific types of nanotubes.

In the Kono lab, metallic nanotubes rose to the top of the spinning vial while nearly all of the semiconducting nanotubes sank to the bottom. What surprised lead researchers Haroz and Rice was that nearly all of the metallic tubes were armchair SWNTs, the most desirable species for the manufacture of quantum nanowire. Zigzag and near-zigzag species, also considered metallic, would also sink out.

Armchair nanotubes are so-called because of their "U"-shaped end segments. Theoretically, armchairs are the most conductive nanotubes, letting electrons charge down the middle with nothing to slow them.

The composition of the gradient solution made a difference in the quality of the samples, Haroz said. "One of the surfactants we're using, sodium cholate, has a molecular structure that's similar to a nanotube -- basically hexagons put together," he said. "We think there's a match between the sodium cholate and the structure of nanotubes, and it binds just a little bit better to an armchair than it does to zigzags."

Hurdles remain in the path to quantum armchair nanowires that nanotechnology pioneer and Nobel laureate Richard Smalley, Haroz' first mentor at Rice who died in 2005, felt would be a panacea for many of the world's problems. Fix the distribution of energy and solutions to other challenges clean water, food, environmental woes will fall into place, he believed.

"Step 1 of the armchair quantum nanowire project is, 'Can we get armchairs?' We've done that," said Haroz. "Now let's make macroscopic structures -- not necessarily long cables, but small structures -- to test their conductivity."


Contact: David Ruth
Rice University

Related biology technology :

1. Soligenix Announces Grant of Broad European Patent for Topically Active Steroids to Treat Inflammatory Gastrointestinal Disorders
2. Archivel Farmas TB Vaccine May Cut Treatment Time From Nine Months to One
3. Latest breakthroughs in technology expand options for diagnosing and treating disease
4. Romark Announces Final Data From Clinical Trial of Nitazoxanide in Treatment-Naive Patients With Genotype 1 Chronic Hepatitis C
5. Santaris Pharma A/S Advances RNA-Targeted Drug Development Candidate Against PCSK9, an Important New Target for the Treatment of High Cholesterol
6. The hot -- and cold -- interventional radiology treatments for recurrent prostate cancer
7. Living longer: Colon cancer patients gain time with radiofrequency ablation treatment
8. Going for gold with a novel interventional radiology treatment for pancreatic cancer
9. Outreach Program to Increase Awareness of New Advances in Biomedical Research to Treat Down Syndrome Cognitive Impairment
10. InterMune Announces Submission of MAA for Pirfenidone for the Treatment of Patients With IPF
11. Peer-reviewed Articles Further Define Clusterin and the Role of a Clusterin Inhibitor, OGX-011, for the Treatment of Cancer
Post Your Comments:
(Date:10/13/2015)... -- the United States , ... about 14% of all new cases of kidney cancer.   ... and Europe .  PRCC represents about ... Hutchison China MediTech Limited ("Chi-Med") (AIM: HCM) today announces that ... (publ) ("AstraZeneca") have completed enrolment in a global Phase II study ...
(Date:10/12/2015)... , Oct.12, 2015  MiMedx Group, Inc. (NASDAQ: ... human amniotic tissue and patent-protected processes to develop and ... Surgical, Orthopedic, Spine, Sports Medicine, Ophthalmic, and the Dental ... which had been filed against the Company has been ... Petit , Chairman and CEO, stated, "As we suspected, ...
(Date:10/12/2015)... 2015 cell surface marker detection market ... according to a new report by Grand View Research, Inc. ... incidence of oncology diseases and other cell-associated disorders. --> ... reach USD 6.49 billion by 2022, according to a new ... can be attributed to rise in incidence of oncology diseases ...
(Date:10/12/2015)... Oct. 12, 2015  Patara Pharma, a clinical-stage ... inflammatory diseases and conditions, today announced the closing ... financing. Concurrent with the close of its sale ... Loan and Security Agreement with Silicon Valley Bank ... million. Patara will use the funds from the ...
Breaking Biology Technology:
(Date:9/10/2015)... This report provides detailed descriptions of the ... emerging sensor types that will dominate in the future. ... the wearable technology hype curve in the last five ... feature with all of them is the prominence of ... useful functions. Sensors collect data about the physical and ...
(Date:9/10/2015)... Report Details The global wearable ... previous expectations of revenues, consumer adoption and even technological ... which wearables begin to achieve that mass market acceptance ... reasons is the entrance of Apple to the SmartWatches ... but the overall size of the wearable technology market. ...
(Date:9/10/2015)... Conn. , Sept. 10, 2015  NXT-ID, Inc. ... biometric authentication company focused on the growing mobile commerce ... based ecommerce site, Touch of Modern, will feature ... Wednesday, September 16 th . ... wide range of designer lifestyle products to its 7.2 ...
Breaking Biology News(10 mins):