A group of Inland scholars see spider silk as a possible material to protect soldiers in war. Soldiers may one day wear body armor made of black widow dragline spider silk.

"Black widow dragline silk is very strong material," said Cheryl Hayashi, an associate professor of biology at the University of California, Riverside. "It's in the 'A' class of silks and it outdoes Kevlar."

Hayashi and a group of scientists at UC Riverside recently unraveled the genetic secrets of black widow spider dragline silk.

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PhotoS By Dan Elliott

Undergraduate student Stuart Le examines colonies of black widow spider eggs.

She and researchers Nadia Ayoub and Jessica Garb identified the DNA sequences for two key proteins in the dragline silk of the black widow.

Hayashi and her team, along with visiting professor Merri Lynn Casem, are working on unraveling more black widow spider silk secrets.

Casem is an assistant professor at the Department of Biological Sciences at Cal State Fullerton. She is studying black widow spider egg silk.

Hayashi and her team are funded by the National Science Foundation, the National Institutes of Health, UC Riverside and the Army Research Office. The UC Riverside Office of Technology Commercialization filed a patent application on the dragline silk gene sequences.

The team worked for a year to map the black widow dragline silk DNA sequence.

The discovery of the dragline silk sequence paves the way for new spider-silk products, including lightweight, super-strong body armor, components of medical devices and high-tech athletic attire.

But spider-silk products hitting the market is a few years away, Hayashi said.

"Engineers, the Department of Defense and others are excited about it," Hayashi said. "The DOD would probably pay for something like body armor, but I think we'll first see it in biomedical uses."

Replace Kevlar?

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Merri Lynn Casem, a visiting professor from UC Irvine, hold a specimen in the lab.

The silk is made of proteins and is biodegradable. If used as body armor it has the potential to replace Kevlar. Kevlar is heavy, costly to produce and difficult to dispose of, she said. Spider-silk armor would be light and strong, and easier to produce with little byproduct waste.

Hayashi gets calls from companies, artists and clothes makers looking to purchase spider silk.

But those companies will have to wait a few more years, she said. When spider silk products hit the market, they probably will be expensive, she said.

Dragline silk could be used in fabrics. The silk has the ability to super-contract. When wet, it shortens and fattens. That could be useful in swimwear, girdles and sports clothes.

But before any products are made from the silk, Hayashi and her team must figure out a way to mass produce it.

So far, the team has managed to insert the DNA sequence into two host organisms. The team inserted the sequence into tobacco and tomato plants grown at UC Riverside. Those host plants produced the silk in a gooey mass of proteins inside their cells. The team harvested the plants, which look normal on the outside, ground them up and extracted the silk proteins.

The next step will be to find a way to spin silk fibers from that mass of proteins.

"Spiders can't be farmed," Hayashi joked. "They eat each other."

Casem, Ayoub and Hayashi gather black widow spiders from campus. The nocturnal spiders are abundant in the area. That was part of the reason Hayashi chose to study the black widow spider, she said.

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The Western Black Widow spider is common in the area. Their web silk may be viable for commercial uses.

The spider supply was abundant, free and handy, she laughed.

Casem uses a wooden spoon to scoop spiders into a jar. Ayoub knocks the spiders out of their webs with a stick and traps them in a jar.

The spiders, when threatened, play dead. Contrary to popular image', black widow spiders are shy.

So far, none of the scientists have been bitten by a black widow, Casem said.

Once they catch the spiders, they keep them in jars, petri dishes and other plastic containers.

They feed the spiders crickets and meal worms. Eventually, the spiders are dissected and studied.

The spiders can live for years in captivity, Casem said. Outside, they live for maybe a season.

Spiders use dragline silk as a safety net. The silk is like a lifeline for the spider. If the spider falls, the spider shoots out dragline silk that attaches to a nearby surface and prevents the spider from falling to its death. The black widow also uses dragline silk for its web. The remarkably strong silk persists in the environment and does not decay, Ayoub said.

Dragline silk is one of seven types of silk produced by spiders.

The dragline silk of black widows is one of the strongest and toughest spider silks identified.

The team is mapping other silk DNA sequences of the black widow spider. They also work with tarantulas.

"There are over 39,000 species of spiders," Hayashi said. "We've got our work cut out for us."