Cheryl Hayashi is not afraid of spiders. She keeps black widows, tarantulas and jumping spiders, to name a few, at her lab at UC Riverside. Last fall, the associate biology professor's promising work on spider silk helped her win a coveted $500,000, no-strings-attached John D. and Catherine T. MacArthur Foundation "genius" grant. In between experiments, Hayashi took a few minutes to explain how her love of spider biodiversity could lead to the next Kevlar.
How did you ever get interested in studying spiders?
When I was an undergraduate there was a professor and she worked on spiders, and she had a part-time job opening to feed her colony of tropical spiders. It just seemed like a good way to get some pizza money.
Sounds like a really cool job. You weren't afraid?
Well, I certainly wasn't the kind of kid that grew up collecting bugs and spiders. Initially it took a little bit of getting used to, but then . . . I just got so fascinated by everything they do: the way they move, the way they look, their colors, the way males look different from females. And you don't work on spiders for very long before you start noticing these beautiful silks that they spin.
What's so interesting about spider silk?
Basically anything we call a spider, whether it's alive today or it's in the fossil record, we know they made silk because they have spinnerets. That means spider silk has been around for over 300 million years. That's almost an unfathomable amount of time. How did it evolve? Where did it come from? All the work so far has suggested that most of the silk proteins are members of [one] gene family. . . . This whole evolutionary aspect is kind of fascinating, too, because spider silk actually evolved well before insect flight.
What have you discovered in your research?
Nearly all spiders make multiple kinds of silk, and each type of silk is made from its own suite of silk proteins. A lot of what we do is trying to clone these silk gene sequences, and then we try to characterize the mechanical properties of the silk fibers. How strong is this fiber? How much can it stretch? In one way, it's thinking of the silk as a building material, as an engineering material. And then we're trying to understand it from an evolutionary standpoint. Does spider A have stronger fibers than spider B? How does that relate to their silk gene sequences?
Does this have uses beyond basic research?
Another part of research our lab is getting into -- this involves other people at UC Riverside -- is to take these spider silk genes and to move them to crop plants in order to make large quantities of silk. It's very labor-intensive if you wanted to actually farm spiders. I always describe it to people as, well, you know, you don't really want to farm tigers. I'll gladly farm a nice quiet crop plant. Just give it some sunlight and have an automatic sprinkler.
Why do you want to make spider silk?
Spider silk, since it's been evolving for hundreds of millions of years, that's a lot of research and development already been done by nature. You want a material that's very strong, that can withstand very high temperature? Let's go study a desert spider. You want one that's very strong that can actually absorb a lot of flying impact? Why don't we study aerial web-weaving spiders. And it turns out that certain spider silks, by weight, are so much stronger and so much tougher than any other known natural or even man-made material.
Where do we stand with synthetic silk? Is it usable?
It's been shown in the laboratory that it works, that we can make transgenic silk. Other labs have shown that they can spin it, but it's all been done in small quantities. We're not quite at the stage where we're going to get an entire clothing line with spider silk, but I think it's going to happen soon.
Probably the first spider silk products are going to be very high-value products. We're going to see it in biomedical fields before we see it as ultra-tough knee patches for jeans, for instance. Even in terms of textiles for clothing it's probably going to be in high-performance athletic gear before we can see it in more mass-market applications.
What are the major challenges in making it?
Spinning the silk proteins turns out to be a really hard thing to do artificially. A lot of really high-tech, really smart labs are working on this. It's a huge engineering problem to go from this liquid silk goo to a dry fiber that faithfully mimics all the fabulous properties of spider silk. I'm always just amazed that that little brown spider in the corner of my apartment is doing it. Whoever comes up with a way they can do that in an industrial scale, that's a multimillion-dollar patent right there.
Are your friends and family creeped out by your research?
Initially I think people were sort of like . . . creepy fascination, but now my family's very used to it. Cheryl and spiders: It kind of just goes together now. Initially they thought it was curious. Could someone really make a living doing that?
Do you have a favorite spider?
Oh, they're all so special. It's really hard to pick. I always like jumping spiders. They're just so darn cute. I really like working with black widows, although I guess maybe especially in Southern California people don't find them so exotic. Another one we've worked on recently is called Liphistius. They make these little burrows with little trap doors and the trap doors have these radiating lines out and the spider stays just behind the door. If you release a cricket into the cage, when the cricket hits one of those radiating lines it's like a trip line -- the spider rushes out, grabs the cricket, and goes back in.
So what's next?
. . . The very first thing on the docket is to have the opportunity to travel to look at spiders in other parts of the world. I know there are really cool silks out there.