Featured Research

from universities, journals, and other organizations

Mussel power: Universal solvent no match for new self-healing sticky gel

Date:
January 31, 2011
Source:
University of Chicago
Summary:
Scientists can now manufacture a synthetic version of the self-healing sticky substance that mussels use to anchor themselves to rocks in pounding ocean surf and surging tidal basins. Potential applications include use as an adhesive or coating for underwater machinery or in biomedical settings as a surgical adhesive or bonding agent for implants.

Mussels can generate their own self-healing sticky material, which allows them to attach to rocks and to repair microtears caused by breaking waves and sand abrasion, but the elastic gel attached to this one was created in the laboratory. A patent is pending on the gel, which is described online in this week's Proceedings of the National Academy of Sciences Early Edition.
Credit: Tara Fadenrecht, Niels Holten-Andersen

Scientists can now manufacture a synthetic version of the self-healing sticky substance that mussels use to anchor themselves to rocks in pounding ocean surf and surging tidal basins. A patent is pending on the substance, whose potential applications include use as an adhesive or coating for underwater machinery or in biomedical settings as a surgical adhesive or bonding agent for implants.

Inspiring the invention were the hair-thin holdfast fibers that mussels secrete to stick against rocks in lakes, rivers and oceans. "Everything amazingly just self-assembles underwater in a matter of minutes, which is a process that's still not understood that well," said Niels Holten-Andersen, a postdoctoral scholar with chemistry professor Ka Yee Lee at the University of Chicago.

Holten-Andersen, Lee and an international team of colleagues are publishing the details of their invention this week in the Proceedings of the National Academy of Sciences Early Edition. Holten-Andersen views the evolution of life on Earth as "this beautiful, amazingly huge experiment" in which natural selection has enabled organisms to evolve an optimal use of materials over many millions of years.

"The mussels that live right on the coast where the waves really come crashing in have had to adapt to that environment and build their materials accordingly," he said.

Many existing synthetic coatings involve a compromise between strength and brittleness. Those coatings rely on permanent covalent bonds, a common type of chemical bond that is held together by two atoms that share two or more electrons. The bonds of the mussel-inspired material, however, are linked via metals and exhibit both strength and reversibility.

"These metal bonds are stable, yet if they break, they automatically self-heal without adding any extra energy to the system," Holten-Andersen said.

A key ingredient of the material is a polymer, which consists of long chains of molecules, synthesized by co-author Phillip Messersmith of Northwestern University. When mixed with metal salts at low pH, the polymer appears as a green solution. But the solution immediately transforms into a gel when mixed with sodium hydroxide to change the pH from high acidity to high alkalinity.

"Instead of it being this green solution, it turned into this red, self-healing sticky gel that you can play with, kind of like Silly Putty," he said. Holten-Andersen and his colleagues found that the gel could repair tears within minutes.

"You can change the property of the system by dialing in a pH," said Ka Yee Lee, a professor in chemistry at UChicago and co-author of the PNAS paper. The type of metal ion (an electrically charged atom of, for example. iron, titanium or aluminum) added to the mix provides yet another knob for tuning the material's properties, even at the same pH.

"You can tune the stiffness, the strength of the material, by now having two knobs. The question is, what other knobs are out there?" Lee said.

This week's PNAS study reports the most recent in a series of advances related to sticky mussel fibers that various research collaborations have posted in recent years. A 2006 PNAS paper by Haeshin Lee, now of the Korea Advanced Institute of Technology, Northwestern's Phillip Messersmith and UChicago's Norbert Scherer demonstrated an elusive but previously suspected fact. Using atomic-force microscopy, they established that an unusual amino acid called "dopa" was indeed the key ingredient in the adhesive protein mussels use to adhere to rocky surfaces.

Last year in the journal Science, scientists at Germany's Max Planck Institute documented still more details about mussel-fiber chemical bonds. The Max Planck collaboration included Holten-Andersen and Herbert Waite of the University of California, Santa Barbara. Holten-Andersen began researching the hardness and composition of mussel coatings as a graduate student in Waite's laboratory.

"Our aspiration is to learn some new design principles from nature that we haven't yet actually been using in man-made materials that we can then apply to make man-made materials even better," he said.

Being able to manufacture green materials is another advantage of drawing inspiration from nature. "A lot of our traditional materials are hard to get rid of once we're done with them, whereas nature's materials are obviously made in a way that's environmentally friendly," Holten-Andersen said.

Citation: "pH-induced metal-ligand cross-links inspired by mussel yield self-healing polymer networks with near-covalent elastic moduli," by Niels Holten-Andersen, Matthew J. Harrington, Henrik Birkedal, Bruce P. Lee, Phillip B. Messersmith, Ka Yee C. Lee, and J. Herbert Waite, Proceedings of the National Academy of Sciences Early Edition, Jan. 24, 2011.


Story Source:

The above story is based on materials provided by University of Chicago. Note: Materials may be edited for content and length.


Journal Reference:

  1. N. Holten-Andersen, M. J. Harrington, H. Birkedal, B. P. Lee, P. B. Messersmith, K. Y. C. Lee, J. H. Waite. pH-induced metal-ligand cross-links inspired by mussel yield self-healing polymer networks with near-covalent elastic moduli. Proceedings of the National Academy of Sciences, 2011; DOI: 10.1073/pnas.1015862108

Cite This Page:

University of Chicago. "Mussel power: Universal solvent no match for new self-healing sticky gel." ScienceDaily. ScienceDaily, 31 January 2011. <www.sciencedaily.com/releases/2011/01/110127110656.htm>.
University of Chicago. (2011, January 31). Mussel power: Universal solvent no match for new self-healing sticky gel. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2011/01/110127110656.htm
University of Chicago. "Mussel power: Universal solvent no match for new self-healing sticky gel." ScienceDaily. www.sciencedaily.com/releases/2011/01/110127110656.htm (accessed July 30, 2014).

Share This




More Matter & Energy News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
China's Drone King Says the Revolution Depends on Regulators

China's Drone King Says the Revolution Depends on Regulators

Reuters - Business Video Online (July 30, 2014) Comparing his current crop of drones to early personal computers, DJI founder Frank Wang says the industry is poised for a growth surge - assuming regulators in more markets clear it for takeoff. Jon Gordon reports. Video provided by Reuters
Powered by NewsLook.com
3Doodler Bring 3-D Printing to Your Hand

3Doodler Bring 3-D Printing to Your Hand

AP (July 30, 2014) 3-D printing is a cool technology, but it's not exactly a hands-on way to make things. Enter the 3Doodler: the pen that turns you into the 3-D printer. AP technology writer Peter Svensson takes a closer look. (July 30) Video provided by AP
Powered by NewsLook.com
Climate Change Could Cost Billions, According To White House

Climate Change Could Cost Billions, According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins