There’s a secret behind the spider’s web, and it could change the way bridges, planes, ships, and even Internet servers are built.
Many varieties of silk, a natural fiber harvested mostly from silkworms, are as strong, if not stronger, than steel - one reason it has been used for generations for such practical purposes as medical sutures.
Now, researchers at the Massachusetts Institute of Technology have discovered why spider silk and the webs made of it have a remarkable molecular ability to survive heavy damage, maintaining the integrity of the web even when individual strands of silk are torn. If scientists can replicate those properties, they can build stronger structures - everything from railroad bridges to body armor for soldiers.
Spider silk fibers soften and stretch without breaking when under stress, such as when a fly hurtles into a web, and then snap back to a rigid state. That property, and the way in which silk strands interact with each other in a web, allow for a stronger, more flexible and more damage-resistant structure than highly engineered human products, said MIT’s team leader, Markus Buehler, an associate professor of civil engineering.
“If there’s a crack in an airplane wing, you’re endangering the whole plane with a catastrophic breakup,’’ he said. “But in a spider web, the damage does not spread. It’s very localized. It sacrifices one of its fibers on behalf of the entire web structure. It has a certain built-in mechanism to repair itself.’’
Buehler compared the entire structure of spider silk and webs, ultimately a complex arrangement of protein strings, to symphony orchestra music. Both have many instruments in play, creating a “symphony of functions,’’ he said.
MIT’s researchers, whose findings were reported last week in the journal Nature, are now studying the “building blocks’’ of spider silk and webs at the nanoscale level. The goal: to see if they can duplicate or mimic the “mechanical properties’’ of this structure from nature.
“If we could copy this, it would mean systems don’t need to be immediately repaired, because they won’t immediately break up,’’ Buehler said. “The trick is to transfer the mechanism of spider webs to other products.’’
The US military, through the Office of Naval Research and the Army Research Office, is monitoring MIT’s research. The agencies are partially funding Buehler’s project, along with the National Science Foundation, according to MIT.
The structural properties of spider webs could conceivably be incorporated into a variety of military items, such as body armor, ship hulls, and land vehicles, Buehler said.
Commercial cars, planes, bridges, and other systems and products could also be made with stronger materials that mimic spider silk, he said.
The damage-control properties of spider webs could potentially be used to build more failure-proof Internet servers, power grids, and other networks, Buehler said. For example, a computer virus can paralyze or destroy a network, spreading damage fast before an antivirus can be employed. But if the World Wide Web could be built to work like a virtual spider web, it would theoretically be able to contain a virus and partially repair itself without catastrophic failure, he said.
David Kaplan, a professor of biomedical engineering at Tufts University who researches properties of silk, said Buehler’s team deserves credit for boring into the molecular level of spider silk.
“Markus’s group has really discovered some insightful properties of silk,’’ said Kaplan, who has collaborated with Buehler on other studies. “He’s adding something new to our understanding.’’
The MIT research will certainly lead to potential new commercial applications for silk, Kaplan said, adding, “It’s such a remarkable material.’’