Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

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

Fine felted nanotubes : Research team of Kiel University develops new composite material made of carbon nanotubes November 22nd, 2017

Report highlights opportunities and risks associated with synthetic biology and bioengineering November 22nd, 2017

Quantum optics allows us to abandon expensive lasers in spectroscopy: Lomonosov Moscow State University scientists have invented a new method of spectroscopy November 21st, 2017

Nano-watch has steady hands November 21st, 2017

Govt.-Legislation/Regulation/Funding/Policy

EC Project Aims at Creating and Commercializing Cyber-Physical-System Solutions November 14th, 2017

Nanobiotix presented new clinical and pre-clinical data confirming NBTXR3ís significant potential role in Immuno-Oncology at SITC Annual Meeting November 14th, 2017

Leti Joins DARPA-Funded Project to Develop Implantable Device for Restoring Vision November 9th, 2017

Nanoshells could deliver more chemo with fewer side effects: In vitro study verifies method for remotely triggering release of cancer drugs November 8th, 2017

Discoveries

Fine felted nanotubes : Research team of Kiel University develops new composite material made of carbon nanotubes November 22nd, 2017

Quantum optics allows us to abandon expensive lasers in spectroscopy: Lomonosov Moscow State University scientists have invented a new method of spectroscopy November 21st, 2017

Nano-watch has steady hands November 21st, 2017

Nanoparticles could allow for faster, better medicine: Exposure of nanoparticles in the body allows for more effective delivery November 20th, 2017

Materials/Metamaterials

Fine felted nanotubes : Research team of Kiel University develops new composite material made of carbon nanotubes November 22nd, 2017

ICN2 researchers compute unprecedented values for spin lifetime anisotropy in graphene November 17th, 2017

Math gets real in strong, lightweight structures: Rice University researchers use 3-D printers to turn century-old theory into complex schwarzites November 16th, 2017

A new way to mix oil and water: Condensation-based method developed at MIT could create stable nanoscale emulsions November 8th, 2017

Announcements

Fine felted nanotubes : Research team of Kiel University develops new composite material made of carbon nanotubes November 22nd, 2017

Report highlights opportunities and risks associated with synthetic biology and bioengineering November 22nd, 2017

Quantum optics allows us to abandon expensive lasers in spectroscopy: Lomonosov Moscow State University scientists have invented a new method of spectroscopy November 21st, 2017

Nano-watch has steady hands November 21st, 2017

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

Fine felted nanotubes : Research team of Kiel University develops new composite material made of carbon nanotubes November 22nd, 2017

Report highlights opportunities and risks associated with synthetic biology and bioengineering November 22nd, 2017

Quantum optics allows us to abandon expensive lasers in spectroscopy: Lomonosov Moscow State University scientists have invented a new method of spectroscopy November 21st, 2017

Nano-watch has steady hands November 21st, 2017

Nanobiotechnology

Fine felted nanotubes : Research team of Kiel University develops new composite material made of carbon nanotubes November 22nd, 2017

Nanoparticles could allow for faster, better medicine: Exposure of nanoparticles in the body allows for more effective delivery November 20th, 2017

Nanobiotix presented new clinical and pre-clinical data confirming NBTXR3ís significant potential role in Immuno-Oncology at SITC Annual Meeting November 14th, 2017

Arrowhead to Present at 29th Annual Piper Jaffray Healthcare Conference November 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