Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



TECH SPACE
Building better silk
by Staff Writers
Boston MA (SPX) Nov 14, 2017


By breaking down the silk and then extruding it through a tiny opening, the researchers found they could produce a fiber twice as stiff as conventional silk and approaching the stiffness of spider drag-line silk. This process could open up a variety of possibilities for new uses. For example, silk is a naturally biocompatible substance that does not produce any adverse reactions in the body, so the new material could be ideal for applications such as medical sutures, or scaffolding for the growth of new skin or other biomaterials.

When it comes to concocting the complex mix of molecules that makes up fibers of natural silk, nature beats human engineering hands down. Despite efforts to synthesize the material, artificial varieties still cannot match the natural fiber's strength.

But by starting with silk produced by silkworms, breaking it down chemically, and then reassembling it, engineers have found they can make a material that is more than twice as stiff as its natural counterpart and can be shaped into complex structures such as meshes and lattices.

The new material is dubbed regenerated silk fiber (RSF) and could find a host of applications in commercial and biomedical settings, the researchers say. The findings are reported in the journal Nature Communications, in a paper by McAfee Professor of Engineering Markus Buehler, postdoc Shengjie Ling, research scientist Zhao Qin, and three others at Tufts University.

Some kinds of silk produced by spiders are among the strongest materials known, pound for pound. But unlike silkworms, spiders cannot be bred to produce the fibers in useful amounts. Various researchers, including Buehler and his collaborators, have attempted to make purely synthetic silk instead, but those efforts have not yet yielded fibers that can match the strength of the natural versions.

Instead, the team has now developed a way to harness the best qualities of natural silk produced by silkworms, while processing it in a way that makes it stronger and opens up a wide variety of new shapes and structures that could never be formed from natural silk.

The key is to break down the natural silk, but not too much, the team says. That is, they dissolve the cocoons built by silkworms, not to the point that the material's molecular structure breaks down but rather into an intermediate form composed of microfibrils. These tiny, thread-like assemblies preserve some of the important hierarchical structures that give the silk its strength.

Buehler, who is the head of the Department of Civil and Environmental Engineering, compares this recycling of materials to tearing down an old brick house. Instead of just knocking the house down into a pile of rubble, however, the individual bricks are carefully separated and then used to build a new structure. "Nature is still better at making the microstructures" that, as demonstrated in some of his earlier research, are responsible for silk's unique stiff, stretchy properties, he says. "In this case, we take advantage of what nature provides."

Though silk thread and fabric are expensive, the material's cost comes mainly from the labor-intensive process of unraveling the thread from the cocoon and weaving it, not from the actual production of the silkworms and their cocoons, which are quite inexpensive, explains Ling. In bulk, unprocessed silkworm cocoons cost only about $5 per kilogram (2.2 pounds), he says.

By breaking down the silk and then extruding it through a tiny opening, the researchers found they could produce a fiber twice as stiff as conventional silk and approaching the stiffness of spider drag-line silk. This process could open up a variety of possibilities for new uses. For example, silk is a naturally biocompatible substance that does not produce any adverse reactions in the body, so the new material could be ideal for applications such as medical sutures, or scaffolding for the growth of new skin or other biomaterials.

The method also allows the researchers to shape the material in ways that could never be duplicated by natural silk. It could be formed, for example, into meshes, tubes, fibers much thicker than natural silk, coils, sheets and other forms. "We're not satisfied with what [the silkworms] make," Buehler says. "We want to make our own new materials."

Such forms can be created by using the reconstituted material in a kind of 3-D printing system customized for silk solution, Qin says. And one advantage of the new process is that it can be carried out using conventional manufacturing technologies, so scaling it up to commercial quantities should not be difficult. The specific properties of the fiber, including its stiffness and toughness, can be controlled as needed simply by varying the speed of the extrusion process.

These reconstituted fibers are also very sensitive to different levels of humidity, and they can be made electrically conductive by adding a thin coating of another material such as a layer of carbon nanotubes. This could enable their use in a variety of sensing devices, where a surface covered with a layer or mesh of such fibers could respond to the press of a fingertip, or to changes in the ambient conditions.

One possible application, for example, might be a bedsheet made from such fibers, Buehler says. Such a sheet could be used in nursing care facilities to help avoid bedsores by monitoring pressure and automatically warning caregivers when a patient has been lying in the same position too long with pressure in a particular area of the body. Such applications could be made practical very quickly, he says, as no real obstacles remain to producing material suitable for such uses.

TECH SPACE
A new way to mix oil and water
Boston MA (SPX) Nov 14, 2017
The reluctance of oil and water to mix together and stay that way is so well-known that it has become a cliche for describing any two things that do not go together well. Now, a new finding from researchers at MIT might turn that expression on its head, providing a way to get the two substances to mix and remain stable for long periods - no shaking required. The process may find applications in ... read more

Related Links
Massachusetts Institute of Technology
Space Technology News - Applications and Research


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

TECH SPACE
Stressed seedlings in space

Orbital ATK's to deliver supplies to International Space Station

How Does Your Space Garden Grow

NanoRacks Deploys Second Kaber-Class Microsatellite This Week, First On-Orbit Assembly

TECH SPACE
Russia embezzlement probe at rocket firm Soyuz

Alaska Aerospace Launches Aurora Launch Services Company

Launch your design with Cheops

NASA Selects Studies for Gateway Power and Propulsion Element

TECH SPACE
NASA Opens $2 Million Third Phase of 3D-Printed Habitat Competition

Insight will carry over two million names to Mars

Opportunity Does a Wheelie and is Back on Solid Footing

Martian Ridge Brings Out Rover's Color Talents

TECH SPACE
China's reusable spacecraft to be launched in 2020

Space will see Communist loyalty: Chinese astronaut

China launches three satellites

Mars probe to carry 13 types of payload on 2020 mission

TECH SPACE
European Space Week starts in Estonia

New Chinese sat comms company awaits approval

Myanmar to launch own satellite system-2 in 2019: vice president

Eutelsat's Airbus-built full electric EUTELSAT 172B satellite reaches geostationary orbit

TECH SPACE
A new way to mix oil and water

Building better silk

Measuring atoms for better navigation and mineral detection

Discovery of a new structure family of oxide-ion conductors SrYbInO4

TECH SPACE
Scientists find potential 'missing link' in chemistry that led to life on earth

18-Month Twinkle in a Forming Star Suggests a Very Young Planet

Overlooked Treasure: The First Evidence of Exoplanets

Atmospheric beacons guide NASA scientists in search for life

TECH SPACE
Watching Jupiter's multiple pulsating X-ray Aurora

Help Nickname New Horizons' Next Flyby Target

Juno Aces 8th Science Pass of Jupiter, Names New Project Manager

Jupiter's X-ray auroras pulse independently




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News






The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement