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Spider silk's real-life superpowers

Degummed silk fibers. Silk fibers are unreeled from the cocoon and boiled to remove the "gum" (sericin) that holds the fibers together and aids in the formation of the cocoon.
Image courtesy of Fiorenzo Omenetto

When you look at a spider web, you might admire its delicate beauty, but don't let appearances deceive you. That web is made of an incredibly tough material—silk!

Silk fibers are event tougher than Kevlar, the synthetic material used in tires, sails and body armor.

Silkworm cocoons. Silkworms spin, depending on breed, between hundreds of meters to over a kilometer of continuous silk fiber to generate a cocoon for protection and permit the development of the pupa.
Image courtesy of Fiorenzo Omenetto

For thousands of years, people have woven silk fibers to make fabric, but silk's real heyday may be yet to come, as researchers find ways to use silk proteins in everything from medical devices to electronics. So say Fiorenzo Omenetto and David Kaplan of Tufts University, who discuss silk's possibilities in a Review article in the 30 July issue of the journal Science.

One of the key mysteries about silk is how spiders, silkworms and other silk-spinning organisms manage to build up such high concentrations of dissolved silk proteins in their glands without the proteins clumping together and precipitating.

Without a solution to this mystery, researchers have had trouble figuring out how to spin solutions of silk proteins mixed in a lab, or to find ways to make synthetic silk. Another way to go might be to develop transgenic animals or plants that could produce silk or even a new generation of silk-like proteins.

If scientists can come up with a way to produce their own silk, they could potentially turn it into gels, films, fibers or sponges, which could each have a variety of uses. For example, silk could be put into artificial tissue for repairing ligaments, bone or other body parts. Or, it might be useful as a packaging material for tiny medical devices that would be implanted in the body to release drugs or take measurements.