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."
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.
A'ndrea Elyse Messer | EurekAlert!
Move over, Superman! NIST method sees through concrete to detect early-stage corrosion
27.04.2017 | National Institute of Standards and Technology (NIST)
Control of molecular motion by metal-plated 3-D printed plastic pieces
27.04.2017 | Ecole Polytechnique Fédérale de Lausanne
More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.
Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...
Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.
"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...
The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.
Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...
The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...
Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.
Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...
20.04.2017 | Event News
18.04.2017 | Event News
03.04.2017 | Event News
27.04.2017 | Life Sciences
27.04.2017 | Physics and Astronomy
27.04.2017 | Earth Sciences