Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Programmable materials find strength in molecular repetition

24.05.2016

Synthetic proteins based on those found in a variety of squid species' ring teeth may lead the way to self-healing polymers carefully constructed for specific toughness and stretchability that might have applications in textiles, cosmetics and medicine, according to Penn State researchers.

"We looked at what is common among squid teeth proteins for all species of squid we studied," said Abdon Pena-Francesch, graduate student in engineering science and mechanics. "We observed which properties changed dramatically for each set of proteins."


Digital Image Correlation shows the fracture of a synthethic protein sample.

Credit: Reginald Hamilton, Penn State

Huihun Jung, a Ph.D. student in Melik Demirel's lab group, looked at four squid species from around the world -- Hawaiian bobtail squid, long-finned squid, European squid and Japanese flying squid.

"It was a mystery why nature uses more than one protein to make the ring teeth in the suckers," said Demirel, professor of engineering science and mechanics. "Why did we need so many? It turns out that each has different mechanical properties."

The proteins in ring teeth are semicrystalline, a combination of crystalline and amorphous pieces. The natural proteins also have varying repeats, amino acid strings that repeat themselves once or many times. These repeats alter the lengths of the protein. However, a clear understanding of the function of these repeats was not known.

After sequencing the various squid proteins, the researchers put together a variety of synthetic ring teeth proteins with varying numbers of repeats. They report their results in the current online issue of the Proceedings of the National Academy of Sciences.

"There has been a lot of work done making structures to mimic proteins," said Demirel, who is also a member of the Huck Institutes of the Life Sciences. "People have looked at the structure of proteins in silk, the elastin in skin, the resilin in insect wings and collagen in a large set of structures, but no one has looked at squid in this way. Squid mimics have not been done before."

Together with Benjamin Allen, research associate in biochemistry and molecular biology and the Huck Institutes, the Demirel group made varying lengths of amino acid strings -- polypeptides -- and found that in the synthetic material, toughness and extensibility increase as the molecular weight increases. The longer the polypeptide chain, the greater the molecular weight. They also found that the balance between elasticity -- how much the material will stretch without deforming -- and plasticity -- the point at which it will deform -- remained unchanged.

"We can control which amino acids we use, so we can control the molecular weights," said Pena-Francesch. "We can design each segment and see what fundamentals of mechanics apply."

The researchers suggest that "the repetitions in native squid proteins could have a genetic advantage for increased toughness and flexibility."

"We found that the shortest polypeptide chains were brittle," said Demirel. "As they get longer, they are stretchy."

The structural properties in this material are highly programmable. Extremely elastic materials, like the amorphous portion of these proteins, absorb energy and are useful in things like automobile bumpers, while the crystalline portion acts like a spring and is more like the material in a car's dashboard. The proper balance of each could provide the desired materials characteristics.

Their building blocks, the synthetic amino acids, are produced by bacteria so that harvesting of live squid is no longer necessary. Also, the synthetic materials are self-healing, so small cracks and breaks can be repaired. Demirel and his team note that the synthetic mimic of the squid ring teeth proteins can be processed to form a variety of 3-dimensional shapes including ribbons, lithographic patterns and nanotubes with a vast array of potential uses.

###

Also working on this project were Reginald F. Hamilton, assistant professor in engineering science and mechanics and the Materials Research Institute; Alham Saadat and Aswathy Sebastian, technicians in biochemistry and molecular biology and the Huck Institutes; Istvan Albert, professor of bioinformatics and member of the Huck Institutes; and Dong Hwan Kim, undergraduate in biology. The researchers have filed a preliminary patent application on this work.

The Office of Naval Research and the Army Research Office.

Media Contact

A'ndrea Elyse Messer
aem1@psu.edu
814-865-9481

 @penn_state

http://live.psu.edu 

A'ndrea Elyse Messer | EurekAlert!

More articles from Materials Sciences:

nachricht Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern
20.07.2018 | Princeton University

nachricht Relax, just break it
20.07.2018 | DOE/Argonne National Laboratory

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>