Corporate Banner
Satellite Banner
Proteomics
Scientific Community
 
Become a Member | Sign in
Home>News>This Article
  News
Return

A Step Toward Stronger Polymers

Published: Tuesday, November 06, 2012
Last Updated: Tuesday, November 06, 2012
Bookmark and Share
Counting loops that weaken materials could help researchers eliminate structural flaws.

Many of the objects we encounter are made of polymers — long chains of repeating molecules. Networks of polymers form manmade materials such as plastics, as well as natural products such as rubber and cellulose.

Within all of these polymeric materials, there are structural flaws at the molecular level. To form an ideal network, each polymer chain would bind only to another chain. However, in any real polymeric material, a significant fraction of the chains instead bind to themselves, forming floppy loops.

“If your material properties depend on having polymers connected to each other to form a network, but you have polymers folded around and connected to themselves, then those polymers are not part of the network. They weaken it,” says Jeremiah A. Johnson, an assistant professor of chemistry at MIT.

Johnson and his colleagues have now developed, for the first time, a way to measure how many loops are present in a given polymer network, an advance they believe is the first step toward creating better materials that don’t contain those weak spots.

Huaxing Zhou, an MIT postdoc, is the lead author of a paper describing the new technique in this week’s issue of the Proceedings of the National Academy of Sciences. Other authors are visiting researcher Jiyeon Woo, chemistry graduate student Alexandra Cok, chemical engineering graduate student Muzhou Wang, and Bradley Olsen, an assistant professor of chemical engineering.

Although polymer chemists have known about these loops since the 1940s, they have had no way to count them until now. In the new paper, the researchers measured the percentage of loops in a gel, but their approach could be used for nearly any type of polymer network, Johnson says.

To measure the number of loops, the researchers first design polymer chains that incorporate a chemical bond, in a specific location, that can be broken using hydrolysis. Once the polymer crosslinks into a gel network, the researchers treat it with a base that cleaves this chemical bond, known as an ester. (Other degradation methods, such as enzymes or light, could also be used.)

Because they know where the break points are, the researchers can predict the percentages of the four different degradation products they should expect to find in an ideal, no-loop network. By measuring the quantity of each degradation product and comparing it with the ideal, they can figure out what fraction of the polymer formed loops.

They found that the percentage of polymer loops ranges from about 9 percent to nearly 100 percent, depending on the concentration of polymers in the starting material and other factors.

“Even in the best material we can make, 9 percent of its junctions are wasted as loops, which tells us that if can figure out a way to reduce loop formation, we’d have a 9 percent improvement in material properties,” Johnson says.

Christopher Bielawski, a professor of chemistry at the University of Texas at Austin, says the new technique overcomes longstanding limitations in chemists’ understanding of the exact structures of polymers.

“The technique is a beautiful combination of experiment, theory and state-of-the-art analytics that takes the field a giant step toward sorting out a problem of tremendous importance,” says Bielawski, who was not part of the research team.

The researchers are now looking for ways to reduce the number of loops by altering the mixture of polymers used to produce a material, as well as the reaction conditions. They are also planning to use their method to study interactions between cells and biological materials. It has already been shown that at the micron scale, cells behave differently depending on the mechanical properties of their environment, such as stiffness.

In their new studies, the MIT researchers want to look at nanoscale interactions between cells and specific protein sequences found in the extracellular matrix, which provides structural support for cells.

The researchers hope to uncover what happens when a cell grabs on to a protein that is looped on itself rather than being attached to the extracellular matrix.

The research was funded by the MIT Department of Chemistry, MIT’s Institute for Soldier Nanotechnologies, and a National Defense Science and Engineering Graduate Fellowship.


Further Information
Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,400+ scientific posters on ePosters
  • More than 3,700+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Bacterial Computing
The “friendly” bacteria inside our digestive systems are being given an upgrade, which may one day allow them to be programmed to detect and ultimately treat diseases such as colon cancer and immune disorders.
Monday, July 13, 2015
New Approach to Global Health Challenges
MIT’s Institute for Medical Engineering and Science brings many tools to the quest for new disease treatments and diagnostic devices.
Friday, September 27, 2013
Why Tumors Become Drug-Resistant
New findings could lead to drugs that fight back when tumors don’t respond to treatment.
Monday, August 12, 2013
Reducing Caloric Intake Delays Nerve Cell Loss
Study points to role of protein in anti-aging benefits of calorie restriction.
Thursday, May 23, 2013
Study IDs Key Protein for Cell Death
Findings may offer a new way to kill cancer cells by forcing them into an alternative programmed-death pathway.
Tuesday, May 14, 2013
Device Finds Stray Cancer Cells in Patients’ Blood
A microfluidic device that captures circulating tumor cells could give doctors a noninvasive way to diagnose and track cancers.
Wednesday, April 10, 2013
Sorting out the Structure of a Parkinson’s Protein
Computer modeling may resolve conflicting results and offer hints for new drug-design strategies.
Tuesday, April 02, 2013
New Technology May Enable Earlier Cancer Diagnosis
Nanoparticles amplify tumor signals, making them much easier to detect in the urine.
Friday, December 21, 2012
Evolution: It’s All in How You Splice It
MIT biologists find that alternative splicing of RNA rewires signaling in different tissues and may often contribute to species differences.
Friday, December 21, 2012
Researchers Synthesize a New Kind of Silk Fiber
Scientists find that music can help fine-tune the material’s properties.
Thursday, November 29, 2012
New Injectable Gels Toughen up after Entering the Body
These more durable gels could find applications in drug delivery and tissue engineering.
Friday, November 16, 2012
A New Glow for Electron Microscopy
Protein-labeling technique allows high-resolution visualization of molecules inside cells.
Monday, October 22, 2012
Oscillating Microscopic Beads Could be Key to Biolab on a Chip
MIT team finds way to manipulate and measure magnetic particles without contact, potentially enabling multiple medical tests on a tiny device.
Tuesday, September 25, 2012
Strategies Converge on Target in Rare Leukemia
In order to treat AMKL in patients who do not respond to current therapies, researchers need a protein target at which to take aim.
Wednesday, August 08, 2012
Researchers Build a Toolbox for Synthetic Biology
Engineers design new proteins that can help control novel genetic circuits in cells.
Friday, August 03, 2012
Scientific News
TOPLESS Plants Provide Clues to Human Molecular Interactions
Scientists at Van Andel Research Institute have revealed an important molecular mechanism in plants that has significant similarities to certain signaling mechanisms in humans, which are closely linked to early embryonic development and to diseases such as cancer.
Toxin from Salmonid Fish has Potential to Treat Cancer
Researchers from the University of Freiburg decode molecular mechanism of fish pathogen.
Study Finds Non-Genetic Cancer Mechanism
Cancer can be caused solely by protein imbalances within cells, a study of ovarian cancer has found.
Long-sought Discovery Fills in Missing Details of Cell 'Switchboard'
A biomedical breakthrough reveals never-before-seen details of the human body’s cellular switchboard that regulates sensory and hormonal responses.
Rice Disease-Resistance Discovery Closes the Loop for Scientific Integrity
Researchers reveal how disease resistant rice detects and responds to bacterial infections.
The Mystery of the Instant Noodle Chromosomes
Researchers from the Lomonosov Moscow State University evaluated the benefits of placing the DNA on the principle of spaghetti.
New Mussel-Inspired Surgical Protein Glue
Korean scientists have developed a light-activated, mussel protein-based bioadhesive that works on the same principles as mussels attaching to underwater surfaces and insects maintaining structural balance and flexibility.
Vital Protein in Healthy Fertilization Process Identified
Researchers at the National Institutes of Health have discovered a protein that plays a vital role in healthy egg-sperm union in mice.
Teeth Reveal Lifetime Exposures to Metals, Toxins
Researchers have identified dental biomarkers to reveal links between early iron exposure and late life brain diseases.
View of Bacterial Pump at the Atomic Level
Researchers have determined the structure of a simple but previously unexamined pump that controls the passage of proteins through a bacterial cell membrane, an achievement that offers new insight into the mechanics that allow bacteria to manipulate their environments.
Scroll Up
Scroll Down
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,400+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
3,700+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FREE!