Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Tiny Channels Carry Big Information

Schematic of a 2-nm nanochannel device, with two microchannels, ten nanochannels and four reservoirs. (Image courtesy of Chuanhua Duan)
Schematic of a 2-nm nanochannel device, with two microchannels, ten nanochannels and four reservoirs. (Image courtesy of Chuanhua Duan)

Abstract:
Researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) have been able to fabricate nanochannels that are only two nanometers (2-nm) in size.

Tiny Channels Carry Big Information

Berkeley, CA | Posted on December 15th, 2010

They say it's the little things that count, and that certainly holds true for the channels in transmembrane proteins, which are small enough to allow ions or molecules of a certain size to pass through, while keeping out larger objects. Artificial fluidic nanochannels that mimic the capabilities of transmembrane proteins are highly prized for a number of advanced technologies. However, it has been difficult to make individual artificial channels of this size - until now.

Researchers with the U.S. Department of Energy (DOE)'s Lawrence Berkeley National Laboratory (Berkeley Lab) have been able to fabricate nanochannels that are only two nanometers (2-nm) in size, using standard semiconductor manufacturing processes. Already they've used these nanochannels to discover that fluid mechanics for passages this small are significantly different not only from bulk-sized channels, but even from channels that are merely 10 nanometers in size.

"We were able to study ion transport in our 2-nm nanochannels by measuring the time and concentration dependence of the ionic conductance," says Arun Majumdar, Director of DOE's Advanced Research Projects Agency - Energy (ARPA-E), who led this research while still a scientist at Berkeley Lab. "We observed a much higher rate of proton and ionic mobility in our confined hydrated channels - up to a fourfold increase over that in larger nanochannels (10-to-100 nm). This enhanced proton transport could explain the high throughput of protons in transmembrane channels."

Majumdar is the co-author with Chuanhua Duan, a member of Majumdar's research group at the University of California (UC) Berkeley, of a paper on this work, which was published in the journal Nature Nanotechnlogy. The paper is titled "Anomalous ion transport in 2-nm hydrophilic nanochannels."

In their paper, Majumdar and Duan describe a technique in which high-precision ion etching is combined with anodic bonding to fabricate channels of a specific size and geometry on a silicon-on-glass die. To prevent the channel from collapsing under the strong electrostatic forces of the anodic bonding process, a thick (500 nm) oxide layer was deposited onto the glass substrate.

"This deposition step and the following bonding step guaranteed successful channel sealing without collapsing," says Duan. "We also had to choose the right temperature, voltage and time period to ensure perfect bonding. I compare the process to cooking a steak, you need to choose the right seasoning as well as the right time and temperature. The deposition of the oxide layer was the right seasoning for us."

The nanometer-sized channels in transmembrane proteins are critical to controlling the flow of ions and molecules across the external and internal walls of a biological cell, which, in turn, are critical to many of the biological processes that sustain the cell. Like their biological counterparts, fluidic nanochannels could play critical roles in the future of fuel cells and batteries.

"Enhanced ion transport improves the power density and practical energy density of fuel cells and batteries," Duan says. "Although the theoretical energy density in fuel cells and batteries is determined by the active electrochemical materials, the practical energy density is always much lower because of internal energy loss and the usage of inactive components. Enhanced ion transport could reduce internal resistance in fuel cells and batteries, which would reduce the internal energy loss and increase the practical energy density."

The findings by Duan and Majumdar indicate that ion transport could be significantly enhanced in 2-nm hydrophilic nanostructures because of their geometrical confinements and high surface-charge densities. As an example, Duan cites the separator, the component placed between the between the cathode and the anode in batteries and fuel cells to prevent physical contact of the electrodes while enabling free ionic transport.

"Current separators are mostly microporous layers consisting of either a polymeric membrane or non-woven fabric mat," Duan says. "An inorganic membrane embedded with an array of 2-nm hydrophilic nanochannels could be used to replace current separators and improve practical power and energy density."

The 2-nm nanochannels also hold promise for biological applications because they have the potential to be used to directly control and manipulate physiological solutions. Current nanofluidic devices utilize channels that are 10-to-100 nm in size to separate and manipulate biomolecules. Because of problems with electrostatic interactions, these larger channels can function with artificial solutions but not with natural physiological solutions.

"For physiological solutions with typical ionic concentrations of approximately 100 millimolars, the Debye screening length is 1 nm," says Duan. "Since electrical double layers from two-channel surfaces overlap in our 2-nm nanochannels, all current biological applications found in larger nanochannels can be transferred to 2-nm nanochannels for real physiological media."

The next step for the researchers will be to study the transport of ions and molecules in hydrophilic nanotubes that are even smaller than 2-nm. Ion transport is expected to be even further enhanced by the smaller geometry and stronger hydration force.

"I am developing an inorganic membrane with embedded sub-2 nm hydrophilic nanotube array that will be used to study ion transport in both aqueous and organic electrolytes,' Duan says. "It will also be developed as a new type of separator for lithium-ion batteries."

This work was supported by DOE's Office of Science, plus the Center for Scalable and Integrated Nanomanufacturing, and the Center of Integrated Nanomechanical Systems at UC Berkeley.

Additional Information

For more information about the research of Arun Majumdar visit http://www.me.berkeley.edu/faculty/majumdar/

For more information about ARPA-E visit the Website at arpa-e.energy.gov/

For more information about the Center for Scalable and Integrated Nanomanufacturing (SINAM) visit www.sinam.org/

For more information about the Center of Integrated Nanomechanical Systems (COINS), visit mint.physics.berkeley.edu/coins/

####

About Berkeley Lab
Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research and is managed by the University of California for the DOE Office of Science.

Visit our Website at www.lbl.gov

For more information, please click here

Contacts:
Lynn Yarris
(510) 486-5375

Copyright © Berkeley Lab

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

Quantum teleportation on a chip: A significant step towards ultra-high speed quantum computers April 1st, 2015

So, near and yet so far: Stable HGNs for Raman April 1st, 2015

Two-dimensional dirac materials: Structure, properties, and rarity April 1st, 2015

3-D neural structure guided with biocompatible nanofiber scaffolds and hydrogels April 1st, 2015

Microfluidics/Nanofluidics

Square ice filling for a graphene sandwich March 26th, 2015

Dolomite’s microfluidics technology ideal for B cell encapsulation March 24th, 2015

Going with the flow January 16th, 2015

How bacteria control their size: By monitoring thousands of individual bacteria scientists discovered how they maintain their size from generation to generation January 6th, 2015

Govt.-Legislation/Regulation/Funding/Policy

Cooling massive objects to the quantum ground state April 1st, 2015

Two-dimensional dirac materials: Structure, properties, and rarity April 1st, 2015

Rutgers, NIST physicists report technology with potential for sub-micron optical switches March 31st, 2015

SUNY Poly CNSE and Title Sponsor SEFCU Name Capital Region Teams Advancing to the Final Round of the 2015 New York Business Plan Competition March 30th, 2015

Possible Futures

Nanotechnology in Medical Devices Market is expected to reach $8.5 Billion by 2019 March 25th, 2015

Nanotechnology Enabled Drug Delivery to Influence Future Diagnosis and Treatments of Diseases March 21st, 2015

Nanocomposites Market Growth, Industry Outlook To 2020 by Grand View Research, Inc. March 21st, 2015

Nanotechnology Drug Delivery Market in the US 2012-2016 : Latest Report Available by Radiant Insights, Inc March 16th, 2015

Academic/Education

SUNY Poly CNSE and Title Sponsor SEFCU Name Capital Region Teams Advancing to the Final Round of the 2015 New York Business Plan Competition March 30th, 2015

LAMDAMAP 2015 hosted by the University March 26th, 2015

SUNY Poly & M+W Make Major Announcement: Major Expansion To Include M+W Owned Gehrlicher Solar America Corporation That Will Create up to 400 Jobs to Develop Solar Power Plants at SUNY Poly Sites Across New York State March 26th, 2015

SUNY POLY CNSE to Host First Ever Northeast Semi Supply Conference (NESCO) Conference Will Connect New and Emerging Innovators in the Northeastern US and Canada with Industry Leaders and Strategic Investors to Discuss Future Growth Opportunities in NYS March 25th, 2015

Announcements

Quantum teleportation on a chip: A significant step towards ultra-high speed quantum computers April 1st, 2015

So, near and yet so far: Stable HGNs for Raman April 1st, 2015

Two-dimensional dirac materials: Structure, properties, and rarity April 1st, 2015

3-D neural structure guided with biocompatible nanofiber scaffolds and hydrogels April 1st, 2015

Battery Technology/Capacitors/Generators/Piezoelectrics/Thermoelectrics/Energy storage

Chemists make new silicon-based nanomaterials March 27th, 2015

New processing technology converts packing peanuts to battery components March 22nd, 2015

NC State researchers create 'nanofiber gusher': Report method of fabricating larger amounts of nanofibers in liquid March 19th, 2015

Drexel Univ. materials research could unlock potential of lithium-sulfur batteries March 17th, 2015

Fuel Cells

Graphene 'gateway' discovery opens possibilities for improved energy technologies March 18th, 2015

Imperfect graphene opens door to better fuel cells: Membrane could lead to fast-charging batteries for transportation March 18th, 2015

Graphene membrane could lead to better fuel cells, water filters March 17th, 2015

CiQUS researchers obtain high-quality perovskites over large areas by a chemical method March 4th, 2015

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







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE