Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Seeing is bead-lieving: Rice University scientists create model 'bead-spring' chains with tunable properties

DNA linkers serve as bridges between colloidal beads in a new experiment by Rice University scientists to study the physics of "bead-spring" polymer chains. They found the chains can be tuned for varying degrees of stiffness or flexibility. Credit: Biswal Lab/Rice University
DNA linkers serve as bridges between colloidal beads in a new experiment by Rice University scientists to study the physics of "bead-spring" polymer chains. They found the chains can be tuned for varying degrees of stiffness or flexibility.

Credit: Biswal Lab/Rice University

Abstract:
Rice University researchers are using magnetic beads and DNA "springs" to create chains of varying flexibility that can be used as microscale models for polymer macromolecules.

Seeing is bead-lieving: Rice University scientists create model 'bead-spring' chains with tunable properties

Houston, TX | Posted on July 28th, 2014

The experiment is visual proof that "bead-spring" polymers, introduced as theory in the 1950s, can be made as stiff or as flexible as required and should be of interest to materials scientists who study the basic physics of polymers.

The work led by Rice chemical and biomolecular engineer Sibani Lisa Biswal and graduate student Julie Byrom was published this month in the American Chemical Society journal Langmuir.

The researchers found the best way to study the theory was to assemble chains of micron-sized colloidal beads with nanoscale DNA springs of various lengths.

"Polymers are classically described as beads connected with springs," Biswal said. "A lot of polymer physicists have come up with scaling laws and intuitive polymer properties based on this very simple concept. But there are very few bead-spring model systems that you can actually visualize. That's why this work came about."

Microscopic solids suspended in a liquid like the fat particles in milk or pigment particles in paint are examples of a colloidal system. Biswal said there has been great interest in creating colloidal molecules, and the Rice experiment is a step in that direction.

To make complex colloidal macromolecules, the researchers started with commercially available, iron-rich polystyrene beads coated with a protein, streptavidin. The beads are charged to repel each other but can connect together with springy DNA fragments. The chains formed when the researchers exposed the beads to a magnetic field.

"We use the field to control particle positioning, let the DNA link the beads together and turn the field off," Biswal said, explaining how the chains self-assemble. "This is a nice system for polymers, because it's large enough to visualize individual beads and positioning, but it's small enough that thermal (Brownian) forces still dictate the chain's motion."

As expected, when they made chains with short (about 500 base pairs) DNA bridges, the macromolecule remained stiff. Longer linkers (up to 8,000 base pairs) appeared to coil up between the beads, allowing for movement in the chain. Surprisingly, when the researchers reapplied the magnetic field to stretch the long links, they once again became rigid.

"Our vision of what's happening is that DNA allows some wiggle room between particles and gives the chain elasticity," Biswal said. "But if the particles are pulled far enough apart, you stress the bridge quite a bit and reduce the freedom it has to move."

Being able to engineer such a wide range of flexibilities allows for more complex materials that can be actuated with magnetic fields, Biswal said.

"This research is interesting because until now, people haven't been able to make flexible chains like this," Byrom said. "We want to be able to explain what's happening across a broad range of polymers, but if you can only make rigid chains, it sort of limits what you can talk about."

Now that they can create polymer chains with predictable behavior, the researchers plan to study how the chains react to shifting magnetic fields over time, as well as how the chains behave in fluid flows.

The paper's co-authors are Rice alum Patric Han and undergraduate Michael Savory. The National Science Foundation supported the research.

####

About Rice University
Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,920 undergraduates and 2,567 graduate students, Rice's undergraduate student-to-faculty ratio is just over 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 2 for "best value" among private universities by Kiplinger's Personal Finance.

Follow Rice News and Media Relations via Twitter @RiceUNews

For more information, please click here

Contacts:
Mike Williams
713-348-6728

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 Links

Read the abstract at:

View the researchers' movies of colloidal chains at:

Biswal Lab:

George R. Brown School of Engineering:

Related News Press

News and information

BSA Distinguished Lecture Tuesday, 10/14: 'LCLS: A Stunning New View Through X-ray Laser Eyes' September 23rd, 2014

Brookhaven Lab's National Synchrotron Light Source II Approved to Start Routine Operations: Milestone marks transition to exciting new chapter September 23rd, 2014

Immune system is key ally in cyberwar against cancer: Rice University study yields new two-step strategy for weakening cancer September 23rd, 2014

Los Alamos Researchers Uncover New Properties in Nanocomposite Oxide Ceramics for Reactor Fuel, Fast-Ion Conductors: Misfit dislocations are key to transport properties across material interfaces September 23rd, 2014

Govt.-Legislation/Regulation/Funding/Policy

Brookhaven Lab's National Synchrotron Light Source II Approved to Start Routine Operations: Milestone marks transition to exciting new chapter September 23rd, 2014

Southampton scientists grow a new challenger to graphene September 23rd, 2014

Nanotubes help healing hearts keep the beat: Rice University, Texas Children’s Hospital patch for defects enhances electrical connections between cells September 23rd, 2014

Immune system is key ally in cyberwar against cancer: Rice University study yields new two-step strategy for weakening cancer September 23rd, 2014

Discoveries

Future flexible electronics based on carbon nanotubes: Study in Applied Physics Letters show how to improve nanotube transistor and circuit performance with fluoropolymers September 23rd, 2014

Nanotubes help healing hearts keep the beat: Rice University, Texas Children’s Hospital patch for defects enhances electrical connections between cells September 23rd, 2014

Immune system is key ally in cyberwar against cancer: Rice University study yields new two-step strategy for weakening cancer September 23rd, 2014

Los Alamos Researchers Uncover New Properties in Nanocomposite Oxide Ceramics for Reactor Fuel, Fast-Ion Conductors: Misfit dislocations are key to transport properties across material interfaces September 23rd, 2014

Materials/Metamaterials

Brookhaven Lab's National Synchrotron Light Source II Approved to Start Routine Operations: Milestone marks transition to exciting new chapter September 23rd, 2014

Southampton scientists grow a new challenger to graphene September 23rd, 2014

Los Alamos Researchers Uncover New Properties in Nanocomposite Oxide Ceramics for Reactor Fuel, Fast-Ion Conductors: Misfit dislocations are key to transport properties across material interfaces September 23rd, 2014

New star-shaped molecule breakthrough: Scientists at The University of Manchester have generated a new star-shaped molecule made up of interlocking rings, which is the most complex of its kind ever created September 22nd, 2014

Announcements

Future flexible electronics based on carbon nanotubes: Study in Applied Physics Letters show how to improve nanotube transistor and circuit performance with fluoropolymers September 23rd, 2014

Nanotubes help healing hearts keep the beat: Rice University, Texas Children’s Hospital patch for defects enhances electrical connections between cells September 23rd, 2014

Immune system is key ally in cyberwar against cancer: Rice University study yields new two-step strategy for weakening cancer September 23rd, 2014

Los Alamos Researchers Uncover New Properties in Nanocomposite Oxide Ceramics for Reactor Fuel, Fast-Ion Conductors: Misfit dislocations are key to transport properties across material interfaces September 23rd, 2014

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals

Future flexible electronics based on carbon nanotubes: Study in Applied Physics Letters show how to improve nanotube transistor and circuit performance with fluoropolymers September 23rd, 2014

Nanotubes help healing hearts keep the beat: Rice University, Texas Children’s Hospital patch for defects enhances electrical connections between cells September 23rd, 2014

Immune system is key ally in cyberwar against cancer: Rice University study yields new two-step strategy for weakening cancer September 23rd, 2014

Los Alamos Researchers Uncover New Properties in Nanocomposite Oxide Ceramics for Reactor Fuel, Fast-Ion Conductors: Misfit dislocations are key to transport properties across material interfaces September 23rd, 2014

Nanobiotechnology

Production of Organometallic Frameworks in Least Possible Time September 23rd, 2014

New star-shaped molecule breakthrough: Scientists at The University of Manchester have generated a new star-shaped molecule made up of interlocking rings, which is the most complex of its kind ever created September 22nd, 2014

Arrowhead to Present at BioCentury's NewsMakers in the Biotech Industry Conference September 19th, 2014

CiQUS researchers design an artificial nose to detect DNA differentiation with single nucleotide resolution September 18th, 2014

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 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE