Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Bendy tubes get around

Abstract:
Rice-led researchers settle argument over mobility of flexible filaments

Bendy tubes get around

Houston, TX | Posted on January 5th, 2011

Theo Odijk, you win. The professor of biotechnology at Delft University of Technology in the Netherlands has a new best friend in Rice University's Matteo Pasquali.

Together with collaborators at the French National Center for Scientific Research (CNRS), the University of Bordeaux, France, and Vrije University, Amsterdam, the Rice professor and his team have settled a long-standing controversy in the field of polymer dynamics: The researchers proved once and for all that Odijk was correct in proclaiming that a little flexibility goes a long way for stiff filaments in a solution.

The study in the current issue of the journal Science shows that even a small ability to bend gives nanotubes and other tiny, stiff filaments the means to navigate through crowded environments, or even such fixed networks as cell matrices.

The work by Pasquali, a professor in chemical and biomolecular engineering and in chemistry, may bring about new ways to influence the motion of tiny filaments by tailoring their stiffness for a given environment.

Nanotubes are being studied for potential use in all kinds of sensing, even in the seemingly disparate fields of biological applications and oil exploration. In both, the ability of nanotubes and other fine, filamentous particles to move through their environments is critical, Pasquali said.

Understanding the motion of a single, flexible polymer chain in a network has been key to scientific advances by Odijk and others on, for example, the behavior of DNA. The Rice researchers expect their revelation to have no less impact.

Pasquali and lead author Nikta Fakhri, a former graduate student at Rice now doing postdoctoral research at the University of Gottingen, Germany, set out to break the deadlocked theories by Odijk and two other scientists who disagreed on the Brownian motion of stiff filaments in a crowded environment, and whether stiffness itself played any part.

"There's a long-standing, fundamental question: How does this threadlike object move when it gets crowded? It could be crowded because it's in a gel, or because there are a lot of threadlike objects with it -- which to that one object looks like a gel," he said.

Crowding constrains the ability of a filament to travel. Think of trying to get from the back to the front of a crowded bus; it takes a certain amount of agility to weave your way through the packed bodies. "It turns out that with a little flexibility, a filament can explore the space around it much more effectively," Pasquali said.

That becomes important when the goal is to get filaments to find and enter a cellular pore to deliver a dose of medication or to act as a fluorescent sensor.

"If you look at the human body, they say we're made of 60 percent water, but we don't slosh around," Pasquali explained. "That's because the water is trapped in pores. Almost all the water in our body is in gel-like structures: inside our cells, which are laden with filamentous networks, or in the interstitial fluid surrounding these cells. We are a big, squishy, porous medium. We need to understand how the nanoparticles move in this medium."

Pasquali and Fakhri mimicked biological networks by using varying concentrations of agarose gel, a porous material often used as a filter in biochemistry and molecular biology for DNA and proteins. The gel forms a matrix of controllable size through which molecules can move.

Nanotubes served as a stand-in for any type of filament, albeit one whose stiffness can be controlled. Like a PVC pipe in the macro world, nanotubes get stiffer as they get thicker; but even the stiffest tubes can flex a bit with length, and these tubes were thousands of times longer than they were wide.

The study started somewhat serendipitously when co-author Laurent Cognet, a researcher at CNRS and the University of Bordeaux, tried to immobilize nanotubes in agarose gels. He noticed in a failed experiment that the nanotubes moved in a "funny way" and discussed it with Pasquali.

Pasquali asked whether the nanotubes were reptating -- scientist lingo for a snakelike motion -- and Cognet said yes. Fakhri, who was studying the dynamics of nanotubes, traveled to the Bordeaux laboratory of Cognet and co-author Brahim Lounis to capture images of the nanotubes in motion.

The resulting spectroscopic and direct still and video images of 35 fluorescent single-walled nanotubes showed them snaking through the gel, probing pores and paths. The nanotubes, like all filaments, obeyed the rules of thermal-induced Brownian motion; they were pushed and pulled by the ever-changing states of the molecules around them.

The research established that flexibility significantly enhances the nanotubes' ability to navigate around obstacles and speeds up their exploration.

Pasquali said Fakhri doggedly pursued her analysis of the nanotubes' motion through computerized image recognition and motion tracking, as well as old-fashioned pencil-and-paper dynamical analysis. He said his longtime collaborator, co-author Frederick MacKintosh, a theoretical physicist at Vrije University, was a tremendous help. MacKintosh has been studying the dynamics of biological networks for nearly two decades.

Pasquali intends to replace the gel with real rocks to see how nanotubes, which can be used as oil-detecting sensors, move in a more structured environment. "Rocks can be a little more complicated," he said. "The question here is, what can nanotubes do better than nanoparticles? The answer may be that slender nanotubes may interact with electromagnetic fields more strongly than other nanoparticles of the same volume."

The National Science Foundation Center for Biological and Environmental Nanotechnology, the Welch Foundation, the Advanced Energy Consortium, the Région Aquitaine, the Agence National pour la Recherche, the European Research Council and the Dutch Foundation for Fundamental Research on Matter supported the work.

Read the abstract at www.sciencemag.org/content/330/6012/1804.abstract

A video of a reptating nanotube can be viewed at www.sciencemag.org/content/330/6012/1804/suppl/DC1

####

About Rice University
Located in Houston, Rice University is consistently ranked one of America's best teaching and research universities. Known for its "unconventional wisdom," Rice is distinguished by its: size -- 3,279 undergraduates and 2,277 graduate students; selectivity -- 12 applicants for each place in the freshman class; resources -- an undergraduate student-to-faculty ratio of 5-to-1; sixth largest endowment per student among American private research universities; residential college system, which builds communities that are both close-knit and diverse; and collaborative culture, which crosses disciplines, integrates teaching and research, and intermingles undergraduate and graduate work.

For more information, please click here

Contacts:
David Ruth
713-348-6327


Mike Williams
713-348-6728

Copyright © Rice University

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

Cryo-electron microscopy achieves unprecedented resolution using new computational methods March 25th, 2017

Argon is not the 'dope' for metallic hydrogen March 24th, 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

Artificial photosynthesis steps into the light: Rice University lab turns transition metals into practical catalyst for solar, other applications March 23rd, 2017

Videos/Movies

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

Rice lab expands palette for color-changing glass: Nanophotonics team creates low-voltage, multicolor, electrochromic glass March 8th, 2017

Water-Repellent Nanotextures Found to Have Excellent Anti-Fogging Abilities: Cone-shaped nanotextures could prevent fog condensation on surfaces in humid environments, including for power generation and transportation applications March 2nd, 2017

Triboelectric Nanogenerators Boost Mass Spectrometry Performance March 1st, 2017

Govt.-Legislation/Regulation/Funding/Policy

Cryo-electron microscopy achieves unprecedented resolution using new computational methods March 25th, 2017

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Nanobiotix: The Independent Data Monitoring Committee Recommends the Continuation of the Ongoing Phase II/III Trial of NBTXR3 in Soft Tissue Sarcoma March 23rd, 2017

Rice U. refines filters for greener natural gas: New study defines best materials for carbon capture, methane selectivity March 23rd, 2017

Possible Futures

Cryo-electron microscopy achieves unprecedented resolution using new computational methods March 25th, 2017

Argon is not the 'dope' for metallic hydrogen March 24th, 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

Rice U. refines filters for greener natural gas: New study defines best materials for carbon capture, methane selectivity March 23rd, 2017

Academic/Education

AIM Photonics Welcomes Coventor as Newest Member: US-Backed Initiative Taps Process Modeling Specialist to Enable Manufacturing of High-Yield, High-Performance Integrated Photonic Designs March 16th, 2017

Nominations Invited for $250,000 Kabiller Prize in Nanoscience: Major international prize recognizes a visionary nanotechnology researcher February 20th, 2017

Oxford Nanoimaging report on how the Nanoimager, a desktop microscope delivering single molecule, super-resolution performance, is being applied at the MRC Centre for Molecular Bacteriology & Infection November 22nd, 2016

The University of Applied Sciences in Upper Austria uses Deben tensile stages as an integral part of their computed tomography research and testing facility October 18th, 2016

Nanotubes/Buckyballs/Fullerenes

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

Captured on video: DNA nanotubes build a bridge between 2 molecular posts: Research may lead to new lines of direct communication with cells January 9th, 2017

Sensors

UC researchers use gold coating to control luminescence of nanowires: University of Cincinnati physicists manipulate nanowire semiconductors in pursuit of making electronics smaller, faster and cheaper March 17th, 2017

Optical fingerprint can reveal pollutants in the air: Researchers at Chalmers University of Technology have proposed a new, sophisticated method of detecting molecules with sensors based on ultra-thin nanomaterials March 15th, 2017

New optical nanosensor improves brain mapping accuracy, opens way for more applications: Potassium-sensitive fluorescence-imaging method shines light on chemical activity within the brain March 3rd, 2017

Smart multi-layered magnetic material acts as an electric switch: New study reveals characteristic of islands of magnetic metals between vacuum gaps, displaying tunnelling electric current March 1st, 2017

Announcements

Cryo-electron microscopy achieves unprecedented resolution using new computational methods March 25th, 2017

Argon is not the 'dope' for metallic hydrogen March 24th, 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

Artificial photosynthesis steps into the light: Rice University lab turns transition metals into practical catalyst for solar, other applications March 23rd, 2017

Research partnerships

Cryo-electron microscopy achieves unprecedented resolution using new computational methods March 25th, 2017

Argon is not the 'dope' for metallic hydrogen March 24th, 2017

Rice U. refines filters for greener natural gas: New study defines best materials for carbon capture, methane selectivity March 23rd, 2017

Artificial photosynthesis steps into the light: Rice University lab turns transition metals into practical catalyst for solar, other applications March 23rd, 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