Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > MIT scientists observe single ions moving through tiny carbon-nanotube channel

MIT chemical engineers built tiny channels out of carbon nanotubes — hollow tubes whose walls are made of lattices of carbon atoms. Small molecules such as sodium ions and protons can flow through the channels.  Graphic: Patrick Gillooly
MIT chemical engineers built tiny channels out of carbon nanotubes — hollow tubes whose walls are made of lattices of carbon atoms. Small molecules such as sodium ions and protons can flow through the channels. Graphic: Patrick Gillooly

Abstract:
Channels could be used for sensitive detectors or water-desalination systems

By Anne Trafton, MIT News Office

MIT scientists observe single ions moving through tiny carbon-nanotube channel

Cambridge, MA | Posted on September 10th, 2010

For the first time, a team of MIT chemical engineers has observed single ions marching through a tiny carbon-nanotube channel. Such channels could be used as extremely sensitive detectors or as part of a new water-desalination system. They could also allow scientists to study chemical reactions at the single-molecule level.

Carbon nanotubes — tiny, hollow cylinders whose walls are lattices of carbon atoms — are about 10,000 times thinner than a human hair. Since their discovery nearly 20 years ago, researchers have experimented with them as batteries, transistors, sensors and solar cells, among other applications.

In the Sept. 10 issue of Science, MIT researchers report that charged molecules, such as the sodium and chloride ions that form when salt is dissolved in water, can not only flow rapidly through carbon nanotubes, but also can, under some conditions, do so one at a time, like people taking turns crossing a bridge. The research was led by associate professor Michael Strano.

The new system allows passage of much smaller molecules, over greater distances (up to half a millimeter), than any existing nanochannel. Currently, the most commonly studied nanochannel is a silicon nanopore, made by drilling a hole through a silicon membrane. However, these channels are much shorter than the new nanotube channels (the nanotubes are about 20,000 times longer), so they only permit passage of large molecules such as DNA or polymers — anything smaller would move too quickly to be detected.

Strano and his co-authors — recent PhD recipient Chang Young Lee, graduate student Wonjoon Choi and postdoctoral associate Jae-Hee Han — built their new nanochannel by growing a nanotube across a one-centimeter-by-one-centimeter plate, connecting two water reservoirs. Each reservoir contains an electrode, one positive and one negative. Because electricity can flow only if protons — positively charged hydrogen ions, which make up the electric current — can travel from one electrode to the other, the researchers can easily determine whether ions are traveling through the nanotube.

They found that protons do flow steadily across the nanotube, carrying an electric current. Protons flow easily through the nanochannel because they are so small, but the researchers observed that other positively charged ions, such as sodium, can also get through but only if enough electric field is applied. Sodium ions are much larger than protons, so they take longer to cross once they enter. While they travel across the channel, they block protons from flowing, leading to a brief disruption in current known as the Coulter effect.

Strano believes that the channels allow only positively charged ions to flow through them because the ends of the tubes contain negative charges, which attract positive ions. However, he plans to build channels that attract negative ions by adding positive charges to the tube.

Once the researchers have these two types of channels, they hope to embed them in a membrane that could also be used for water desalination. More than 97 percent of Earth's water is in the oceans, but that vast reservoir is undrinkable unless the salt is removed. The current desalination methods, distillation and reverse osmosis, are expensive and require lots of energy. So a nanotube membrane that allows both sodium and chloride ions (which are negatively charged) to flow out of seawater could become a cheaper way to desalinate water.

This study marks the first time that individual ions dissolved in water have been observed at room temperature. This means the nanochannels could also detect impurities, such as arsenic or mercury, in drinking water. (Ions can be identified by how long it takes them to cross the channel, which depends on their size). "If a single arsenic ion is floating in solution, you could detect it," says Strano.

Source: "Coherence Resonance in a Single Walled Carbon Nanotube Ion Channel" by Chang Young Lee, Wonjoon Choi, Jae-Hee Han, and Michael S. Strano. Science, 9 September, 2010.

Funding: Institute for Soldier Nanotechnology at MIT, U.S. Army Research Office, and a fellowship from the Sloan Foundation

####

For more information, please click here

Contacts:
Jen Hirsch
MIT News Office

T: 617-253-1682

Copyright © MIT

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Video captures bubble-blowing battery in action: Researchers propose how bubbles form, could lead to smaller lithium-air batteries April 26th, 2017

New Product Nanoparticle preparation from Intertronics with new Thinky NP-100 Nano Pulveriser April 26th, 2017

California Research Alliance by BASF establishes more than 25 research projects in three years April 26th, 2017

Affordable STM32 Cloud-Connectable Kit from STMicroelectronics Puts More Features On-Board for Fast and Flexible IoT-Device Development April 26th, 2017

Chemistry

Shedding light on the absorption of light by titanium dioxide April 14th, 2017

Researchers uncover secret of nanomaterial that makes harvesting sunlight easier March 29th, 2017

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

Researchers develop groundbreaking process for creating ultra-selective separation membranes: Discovery could greatly improve energy-efficiency of separation and purification processes in the chemical and petrochemical industries March 15th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Graphene holds up under high pressure: Used in filtration membranes, ultrathin material could help make desalination more productive April 24th, 2017

Nanoparticle vaccine shows potential as immunotherapy to fight multiple cancer types April 24th, 2017

NanoMONITOR shares its latest developments concerning the NanoMONITOR Software and the Monitoring stations April 21st, 2017

Better living through pressure: Functional nanomaterials made easy April 19th, 2017

Possible Futures

Video captures bubble-blowing battery in action: Researchers propose how bubbles form, could lead to smaller lithium-air batteries April 26th, 2017

California Research Alliance by BASF establishes more than 25 research projects in three years April 26th, 2017

Geoffrey Beach: Drawn to explore magnetism: Materials researcher is working on the magnetic memory of the future April 25th, 2017

Nanoparticle vaccine shows potential as immunotherapy to fight multiple cancer types April 24th, 2017

Academic/Education

California Research Alliance by BASF establishes more than 25 research projects in three years April 26th, 2017

SUNY Polytechnic Institute Announces Total of 172 Teams Selected to Compete in Solar in Your Community Challenge: Teams from 40 states, plus Washington, DC, 2 Territories, and 4 American Indian Reservations, Will Deploy Solar in Underserved Communities April 20th, 2017

Rice crew revved for Nanocar Race: Nanocar creator James Tour and team take on international competition with single-molecule marvel April 20th, 2017

The Catholic University of Rome uses the JPK NanoWizard® AFM & CellHesion® systems to understand how cells sense and respond to mechanical stimuli April 5th, 2017

Nanotubes/Buckyballs/Fullerenes

Nanotubes that build themselves April 14th, 2017

Intertronics introduce new nanoparticle deagglomeration technology March 15th, 2017

Boron atoms stretch out, gain new powers: Rice University simulations demonstrate 1-D material's stiffness, electrical versatility January 26th, 2017

New stem cell technique shows promise for bone repair January 25th, 2017

Sensors

Better living through pressure: Functional nanomaterials made easy April 19th, 2017

A Sensitive And Dynamic Tactile Sensor Read more from Asian Scientist Magazine at: https://www.asianscientist.com/2017/04/tech/tactile-3d-active-matrix-sensor/ April 18th, 2017

AIM Photonics Presents Cutting-Edge Integrated Photonics Technology Developments to Packed House at OFC 2017, the Optical Networking and Communication Conference & Exhibition April 11th, 2017

New technology could offer cheaper, faster food testing: Specialized droplets interact with bacteria and can be analyzed using a smartphone April 7th, 2017

Announcements

Video captures bubble-blowing battery in action: Researchers propose how bubbles form, could lead to smaller lithium-air batteries April 26th, 2017

New Product Nanoparticle preparation from Intertronics with new Thinky NP-100 Nano Pulveriser April 26th, 2017

California Research Alliance by BASF establishes more than 25 research projects in three years April 26th, 2017

Affordable STM32 Cloud-Connectable Kit from STMicroelectronics Puts More Features On-Board for Fast and Flexible IoT-Device Development April 26th, 2017

Water

Using light to propel water : With new method, MIT engineers can control and separate fluids on a surface using only visible light April 25th, 2017

Graphene holds up under high pressure: Used in filtration membranes, ultrathin material could help make desalination more productive April 24th, 2017

Wood filter removes toxic dye from water April 21st, 2017

Shedding light on the absorption of light by titanium dioxide April 14th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project