Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists spin artificial silk from whey protein

24.01.2017

X-ray study throws light on key process for production

A Swedish-German team of researchers has cleared up a key process for the artificial production of silk. With the help of the intense X-rays from DESY's research light source PETRA III, the scientists could watch just how small protein pieces, called nanofibrils, lock together to form a fibre.


Hydrodynamic focussing by means of perpendicular water streams makes protein nanofibrils lock together in a microfibre.

Credit: DESY/Eberhard Reimann

Surprisingly, the best fibres are not formed by the longest protein pieces. Instead, the strongest "silk" is won from protein nanofibrils with seemingly less quality, as the team around Dr. Christofer Lendel and Dr. Fredrik Lundell from the Royal Institute of Technology (KTH) in Stockholm reports in the Proceedings of the U.S. National Academy of Sciences.

Due to its many remarkable characteristics, silk is a material high in demand in many areas. It is lightweight, yet stronger than some metals, and can be extremely elastic. Currently, silk is harvested from farmed silkworms, which is quite costly. "Across the globe, many research teams are working on methods to artificially produce silk," says co-author Prof. Stephan Roth from DESY who is an adjunct professor at KTH Stockholm. "Such artificial materials can also be modified to have new, tailor-made characteristics and can serve for applications like novel biosensors or self-dissolving wound dressings, for example."

However, imitating nature proved especially hard in the case of silk. The Swedish team focuses on self-assembling materials. "That's a quite simple process," explains Lundell. "Some proteins assemble themselves into nanofibrils under the right conditions. A carrier fluid with these protein nanofibrils is then pumped through a small canal. Additional water enters perpendicular from the sides and squeezes the fibrils together until they stick together and form a fibre."

The latter process is called hydrodynamic focussing, and Lundell's team has used it before for producing artificial wood fibres from cellulose fibrils. "In fact, the process has several similarities with the way spiders produce their silk threads," says Lendel.

In the new study, the nanofibrils were formed by a protein from cow's whey under the influence of heat and acid. The fibrils shape and characteristics strongly depend on the protein concentration in the solution. At less than four per cent, long, straight and thick fibrils form. They can be up to 2000 nanometres long and 4 to 7 nanometres thick. But at an only slightly higher protein concentration of six per cent or more in the initial solution, the fibrils remain much shorter and thinner with an average length of just 40 nanometres and a thickness of 2 to 3 nanometres. Also, they are curved looking like tiny worms and 15 to 25 times softer than the long, straight fibrils.

In the lab, however, the short and curved fibrils formed much better fibres than the long and straight fibrils. With DESY's bright X-ray light, the researchers could find out why: "The curved nanofibrils lock together much better than the straight ones. The X-ray diffraction patterns show that they largely keep their rather random orientation in the final fibre," says Roth, head of the beamline P03 at PETRA III where the experiments took place.

"The strongest fibres form when a sufficient balance between ordered nanostructure and fibril entanglement is kept," adds Lendel. "Natural silk is an even more complex structure with evolutionary optimized proteins that assemble in a way with both, highly ordered regions - so-called beta-sheet - that give strength and regions with low order that give flexibility. However, the structures of the artificial and natural fibers are essentially different. In particular, the protein chains in natural silk have a larger number of intermolecular interactions that cross-link the proteins and result in a stronger fiber."

In their experiments, the researchers obtained artificial silk fibres that were roughly five millimetres long and of medium quality. "We used the whey protein to understand the underlying principle in detail. The whole process can now be optimised to obtain fibres with better or new, tailor-made properties," says Lendel. This way, the results of the study could help to develop materials with novel features, for example artificial tissue for medical applications.

###

Deutsches Elektronen-Synchrotron DESY is the leading German accelerator centre and one of the leading in the world. DESY is a member of the Helmholtz Association and receives its funding from the German Federal Ministry of Education and Research (BMBF) (90 per cent) and the German federal states of Hamburg and Brandenburg (10 per cent). At its locations in Hamburg and Zeuthen near Berlin, DESY develops, builds and operates large particle accelerators, and uses them to investigate the structure of matter. DESY's combination of photon science and particle physics is unique in Europe.

Reference

Flow-assisted assembly of nanostructured protein microfibers; Ayaka Kamada, Nitesh Mittal, L. Daniel Söderberg, Tobias Ingverud, Wiebke Ohm, Stephan Roth, Fredrik Lundell, Christofer Lendel; Proceedings of the National Academy of Sciences (PNAS), 2017; DOI: 10.1073/pnas.1617260114

Media Contact

Dr. Thomas Zoufal
presse@desy.de
49-408-998-1666

 @desynews

http://www.desy.de 

Dr. Thomas Zoufal | EurekAlert!

Further reports about: DESY Elektronen-Synchrotron PETRA III X-ray artificial fibrils nanometres proteins silk

More articles from Life Sciences:

nachricht Could this protein protect people against coronary artery disease?
17.11.2017 | University of North Carolina Health Care

nachricht Microbial resident enables beetles to feed on a leafy diet
17.11.2017 | Max-Planck-Institut für chemische Ökologie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>