Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Water No Match for New Self-Healing Sticky Gel

Universal solvent no match for new self-healing sticky gel

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 on how to make the substance is pending. 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. 24-28, 2011.

Funding: National Science Foundation, National Institutes of Health, National Aeronautics and Space Administration, and Danish Council for Independent Research/National Sciences.

Steve Koppes | Newswise Science News
Further information:

Further reports about: Gel Max Planck Institute PNAS Water Snake chemical bond self-healing

More articles from Materials Sciences:

nachricht Researchers demonstrate existence of new form of electronic matter
15.03.2018 | University of Illinois at Urbana-Champaign

nachricht Boron can form a purely honeycomb, graphene-like 2-D structure
15.03.2018 | Science China Press

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

Im Focus: Locomotion control with photopigments

Researchers from Göttingen University discover additional function of opsins

Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...

Im Focus: Surveying the Arctic: Tracking down carbon particles

Researchers embark on aerial campaign over Northeast Greenland

On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...

Im Focus: Unique Insights into the Antarctic Ice Shelf System

Data collected on ocean-ice interactions in the little-researched regions of the far south

The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...

Im Focus: ILA 2018: Laser alternative to hexavalent chromium coating

At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.

When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

TIB’s Visual Analytics Research Group to develop methods for person detection and visualisation

19.03.2018 | Information Technology

Tiny implants for cells are functional in vivo

19.03.2018 | Interdisciplinary Research

Science & Research
Overview of more VideoLinks >>>