Scientists Weave Spider Silk Into New Bulletproof Vests.

• Author: Willingham, Stephen

A product that spiders have been crafting for perhaps 400 million years is being developed to protect military and law enforcement personnel.

The material is spider-dragline filament, from which arachnids spin their webs. It is one of the strongest materials in the world--many times stronger than steel--Jeffrey D. Turner, president of Nexia Biotechnologies, in Montreal, told National Defense in a recent interview. Spider silk's tensile strength is such that it can withstand weight of up to 300,000 pounds per square inch, he said.

Scientists currently are developing dragline filament for use in the next generation of bulletproof vests.

Currently, bulletproof vests are made of Kevlar, which provides a dependable barrier against bullets. Soldiers and police personnel, however, report that Kevlar vests are heavy; inflexible and hot to wear. Vests made of dragline filament may resolve these problems, Turner said.

Thus far, no vests have been made of spider silk. The biggest roadblock has been finding a sufficient quantity of filament to weave materiel for ballistic-protection garments, Turner explained.

For many years, scientists have sought a way to mass-produce this filament. The problem is that arachnids are notoriously anti-social, Turner pointed out. They much prefer individual territory to living in social groups. This greatly complicates the task of producing large quantities of the silk.

In 1999, Nexia signed research and development agreements with the U.S. Defense Department and the Canadian Department of National Defense to try to solve this problem.

Boosting Production

Nexia's strategy is to use the latest transgenic animal technology to boost spider silk production. Nexia has cloned several New Zealand miniature goats that have a silk-producing gene added to their genome. These animals will form the foundation for a herd that will share an identical genetic makeup that Nexia scientists anticipate will produce from two to 15 grams of spider silk per liter of milk, a vast increase over the amount provided naturally by individual spiders.

"Two to 15 grams of silk per liter of milk doesn't seem like a lot until you consider that we will be dealing with many thousands of gallons of milk," Turner explained. Eventually, Nexia wants to produce as much as five tons of silk per year, he said.

The silk-producing gene added to the goats is a form of recombinant DNA-- which means they can pass the gene on to their offspring, without the need for technicians to introduce it to each new...