Spider lab constructs ‘silk library’
Efforts could advance lightweight materials
NEW YORK — With two pairs of fine-tipped tweezers and the hands of a surgeon, Cheryl Hayashi began dissecting the body of a silver garden spider under her microscope.
In a few minutes she found what she was seeking: hundreds of silk glands, the organs spiders use to make their webs. Each lets the spider produce a different type of silk.
Some silk types can be stretchy, others stiff. Some dissolve in water, others repel it.
“They make so many kinds of silk!” Hayashi said. “That’s just what boggles my mind.”
Hayashi has collected spider silk glands of about 50 species, just a small dent in the more than 48,000 spider species known worldwide. Her lab at the American Museum of Natural History is uncovering the genes behind each type of silk to create a sort of “silk library.” It’s part of an effort to learn how spiders make so many kinds of silk and what allows each kind to behave differently.
The library could become an important storehouse of information for designing new pesticides and better materials for bullet-proof vests, space gear and biodegradable fishing lines.
Hayashi has been at this for 20 years, but improved technology only recently let scientists analyze the DNA of silk faster and produce artificial spider silk in bulk.
“Any function that we can think of where you need something that requires a lightweight material that’s very strong, you can look to spider silk,” Hayashi said.
Spider silks all start out the same: a wad of goo, akin to rubber cement or thick honey. Spiders make and stash it in a gland until they want to use the silk. Then, a narrow nozzle called a spigot opens. And as the goo flows out, it morphs into a solid silk strand that is weaved with other strands emerging from other spigots.
How and why silks behave in these various ways is a puzzle, but the secret likely lies in genes.
Scientists have to recover the full gene to truly mimic natural silk. If they try to produce synthetic silk from just part of a gene or some lab-built stunted version, “it’s not as good as what a spider makes,” said Sarah Stellwagen from the University of Maryland, Baltimore County.