Harnessing the superpowers of silk

- Hey, it's Laura Lichtman and you're listening

to Science Friday.

“You may have seen that the next Spider-Man movie”

comes out this summer, the trailer, which came out just this month, hit a billion views. - Because I'm not just Peter Parker, I'm Spider-Man.

- And relatedly, in a superhero story, this would be called a twist of fate, this question came in on our listener line. - My name is Christian, I'm in Richmond, but you know, I'm healing from Pennsylvania, you know, the vibes.

I'm calling because I want to say inquire about my ability to have a pair of functioning web shooters, so I can operate as a local Spider-Man and I would love for you guys to let me know. - Okay Christian, sci-fi to the rescue,

although web shooters for now are the stuff of sci-fi, the Spider-Verse did get this right. So seems to have superpowers. So what can Spider-self really do and how are people trying to harness it?

On the line is Spider-self biologist Dr. Cheryl Hayashi, Senior Vice President and Provost of Science at the American Museum of Natural History. Cheryl, thanks for joining me. - Thank you.

- Off the bat, give me your first reaction to Christian's question. I love that question.

We should always be inspired by nature,

“and who doesn't want to have web shooters on their body?”

- I agree. Is this a personal fantasy for you? - It's not a swing from buildings, but a personal fantasy for me would be, if I could be a spider for a day

and actually have the coordination and the ability to weave a web, that would just be amazing. To weave a web, that would be your fantasy. Why am I talking to you?

- I might ask you the web. - Because it's one of the most remarkable wondrous structures that's in nature, in order to make a web, a spider has to be able to make the silk

and they make that silk in their body. So in their abdomen, they have little tiny glands that pump out silk protein, and then they have little spinner rats on their abdomen, and they touch their legs to the spinner rats,

and that's how they pull silk out. And then they have to have sort of the right choreography in order to construct a web, and that's just really hard to do.

It's just an amazing, amazing feat

of engineering and design. - Yeah, okay, I mean, I wanna be able to picture this like in Marvel movies, you know, the silk is shooting out of, I guess, spinner rats, glands in Peter Parker's

or Spider-Man's wrists. What does it actually look like on a spider? - Each kind of, so a spider has many, many silk glands, and most spiders have many types of silk gland, and each has its own recipe,

its own recipe of silk ingredients. And so what comes out of these silk glands is a variety of different types of silk. Some types of silk are really strong, some types of silk are stretchy, some are sticky.

Can they tune the recipe for the area of the web that they're making? - They do that in terms of, they use, they draw out a particular kind of silk for the particular architectural element of the web.

So for instance, the frame and sort of the radii sort of the spokes, that's one kind of silk, and a different kind of silk, a much stretch of your silk, would be used as the spiral that gets laid on the spokes.

And so spiders are mixing and matching, the different kinds of silks they make, depending on what they need to do with their silk. - So it's not really spider silk, it's spider silks. - Exactly, there's not just one kind of spider silk,

each spider makes at least one kind of silk, and each type of spider silk is made up of its own set

“of proteins, so that's why I always say silks,”

so a lot of S's in there, and there's over 53,000 described species of spiders, and so if you kind of do the math, that most of them make more than one kind of silk, there's a lot of silk out there,

a lot of spider silks to be said. - Wow, like in the tens of thousands, say least. - Oh my gosh, yes, yes, like yes. - What were you gonna say? - I would add a few more zeros to that.

- So we hear these big claims with spider silk. Like, it's stronger than steel, it's tougher than Kevlar. Is that true for some silks? - Oh yes, it is true for some silks, and you know, people might say, how could that be true,

So spider silk is often so thin,

“you can barely see it, so it's very fine fibers,”

and so, but they're able to do things like, stop flying insect, like that takes a lot of strength and toughness. - Yeah, okay, spider man obviously shoots silk out, and then uses it as a mode of transportation. Do spiders use silk that way?

- So spiders, they don't necessarily shoot silk out like the way spider man does. Spiders tend to more pull silk out, or they might attach silk to a substrate, maybe it's, you know, the eve of your window or a branch,

and then they might use gravity to drop from it. So that's a common way that spider silk gets drawn out, and then they can sort of walk on that line. Some spiders, especially tiny little spider links, let some silk out, and it functions sort of like,

like a little parachute or a little sail, so they can be caught by the wind, and we call that ballooning. So spiders can basically fly around the earth. In fact, you can even find spiders at high altitude,

little tiny spiders at high altitude, flying with their drag lines.

So spiders never evolved wings,

but they can fly with their silk. - That's wild. Are there any other sort of lesser known uses of silk that we should call out? - Sure, so some other lesser known uses of silk is,

there's another spider called a bolla spider, which has changed their orb web down to a single line with a single ball of sticky glue at the end. So it's like a little bolla snott with a little string attached to it,

and when insects approach that spider, that spider starts swinging that bollus, and then that little sticky ball gets stuck to the insect, and the insect goes into tethered flight, and the spider can reel it in.

“I think that's a super cool use for literally being a web slinger.”

- A spider lasso, I love it. - Yes, yes.

- Okay, I mean, here's the thing.

I don't think I'm speaking at a turn here. I don't think I'm gonna say anything that's surprising. Spiders look are not particularly well-loved, I would say generally. And yet, they do confer the scrape power

in one of our most beloved superheroes. How do you think about our relationship with spiders? - Oh, that's a good question. Of course, I don't really relate to this thing about spiders not being beloved.

I find them absolutely fascinating. And so, yeah, I think that, I think it's fair though that they inspire, right? I mean, they're so amazing. They've been spinning silk for hundreds of millions of years.

They're nearly everywhere on an all-terrestrial habitat. There's even some spiders that live underwater. So, I think they've earned their place in terms of inspiring us. - Underwater spiders?

- Yeah, there are a few spiders that live underwater.

They spiders never evolved gills.

So, they do need to have air. So, you might wanna guess what they drop their air with. I'm gonna guess the most amazing, material known to man, spider silk. - Yeah, they basically go to the surface

and air sticks to their little hairs and their waxy body. And then they can capture the air bubble and then they can put into their little silk chamber. - It's like a spider silk.

A spider silk scuba tank. - Yeah, yeah, it's just, they basically and they can hang out in there. And that's, they can go back up to the surface and replenish, but there are some spiders

that live underwater. There's spiders that live on the shoreline and that high tide, they'd be submerged and it low tide, they're out. So, what they do is they live in little burrows

and they have a little door on it and make a little waterproof door. And you might wanna guess what is that waterproof door made of? - Silk?

- Yes, it's just amazing. It's like better than duct tape. - Better than duct tape. Oh, I love that. I mean, are people trying to harness the power

of spider silk? Like, is that a thing? - Oh, that's definitely a thing. So, it's been long recognized that spider silk has these remarkable properties

and so there's been a considerable effort into trying to understand what's the secret. So, people's study, the silk proteins, they study the silk structure and there are people that study,

well, how can we replicate this? Do we replicate it by sort of,

“do we mimic the structure using other chemical means?”

Or do we actually try to make a lot of silk protein? And there's research going on in all those areas.

Is it the fabrication?

“- The fabrication does seem to be quite difficult”

and it's just an amazing thing that,

when you either watch a spider make a web or you just see silk lying around your house or outdoors that there's a little creature that's doing something that seems so effortless for them that is really hard for humans to do.

- Dr. Cheryl Hayashi, Senior Vice President and Provost for Science at the American Museum of Natural History in New York City. Cheryl, thanks for joining me today. - Thanks.

- We gotta take a break, but along those lines, when we come back, we're talking to a biomedical engineer who's trying to do just that to fabricate silk and use it for devices like sensors and implants. Don't go away.

- Up next, let's talk about fabrication and how exactly scientists are putting insect silk to use.

“Here to pull that thread with us is Dr. Fiorenso Aminato,”

a biomedical engineer and director of the Silk Lab at Tufts University in Massachusetts. Theo, welcome back to Science Friday. - Thank you. - You run a whole lab devoted

to finding silk applications. Why silk? - Oh, gosh, what a tough question to answer because from a material standpoint, it's a very nice technical material

so it can be formed on the nanoscale. It can interface with electronics. It can make very solid blocks and so have all these material formats that are very versatile.

But the thing that silk really does is it's able to store and preserve the activity of what you mix inside of it in these end formats. And an example is, for instance, if you take this a glass of silk and you add some blood

inside of it and then you pour it on the table and you let it dry. Once you lift up a sheet of material that looks like a red transparent film of plastic and you can leave it on the table for several months

and then cut a little piece and send it to the hospital and then they'll take the blood out and your analysis, your labs from that blood art, just as good as a fresh blood draw. - What?

So it's like a crazed, that's an amazing preservation device.

It's the one thing that makes working with this material very exciting because you can hide superpowers in materials. So it's really, it's really a material scientist dream. It gives a lot of opportunity to explore and domains

that are otherwise very hard to explore. - And you use warm silk, right? Not spider silk. And we use silk warm silk, yes. We use silk that commonly is used

as a commodity material for textiles. So there's an abundance of it and we deconstructed into its liquid state so that we can then reform it into a variety of materials. - What is it about silk?

Like what's the secret sauce that allows it to do this

“that allows you to store superpowers in a material?”

- You know, I wish I could tell you, I could tell you that this was designed with purpose and equations and long hours, but I think that this is something that comes from directed evolution of, in this case,

from domesticating the silkworm over thousands of years. And ultimately, the selection was to make the strongest, finest, the most lustrous fiber that would give you, you know, the subless scars and the best garments that you could weave.

But ultimately, this gave a molecule, a particular kind of molecule that is very, very unusual and the way that it assembles. And then the way that it interfaces with the materials that it's mixed with.

So I think it's really, it's really nature's offering in a way of a very technologically sophisticated polymer that happens to be very benign and very friendly to interface with the body or to disperse in the environment.

- I mean, I feel like I always,

I often see silk for sensors, you know, like biosensors or, you know, within the body or outside. Is that again just because the silk can hold the actual sensing material and keep it stable

or is it playing any other role?

- Well, there's a little bit of both.

“I think that the main advantage of the main feature”

is really that silk will stabilize chemistries that otherwise otherwise are confined to laboratories and to wet labs into a lab bench. And so, and so you can imagine, really, that you can make silkings that contain enzymes

that otherwise would need to be refrigerated and you can just print them on surfaces and then just look at the way that the surfaces react to the environment around them.

And so, this is a very nice way

of using this stabilization function and the bioavailability to do all sorts of all sorts of sensing from little adhesive patches and, you know, in band-aid type reporters to printed t-shirts that react to your body

to tapestries that you hang in a room and respond to the environment around it. - I do know on my t-shirts responding to my body more than I already do, just saying. Okay, are there silk uses in the wilds

that I might encounter at a store? - So, the process of generating silk pollution has been scaled up and has been put to industrial use and food preservation in vaccines civilization to give a couple of examples.

And now the production has been scaled to very large amounts. So, so yes, you may encounter it in these domains. - Yeah, I love that this very ancient bio material is being used in these kind of futuristic sounding ways. How do you think about that?

- I think that it's beautiful.

“I think that there's a recontext realization”

of things that used to be artisan skills and have been around for such a long time. But there's a beauty and reimagining things and finding new contexts for materials that have been around for a long time.

Sometimes I talk about, like give this example of, maybe there's an artisan in the world that is just the best person at doing shoelaces and braiding the best shoelaces on the planet and this craft has been pushed out

by industrialization and volume and scale. But that craft becomes contemporary if the material that you used to make to make the shoelaces now becomes a material that is medically relevant and can be used to replace ligament and tendons.

And so all of these things that we have around and that have all these unbelievable properties, either from nature or from people using natural materials

“have, I think a beautiful, a beautiful second life”

and maybe a third in a fourth life.

- It's a lovely place to end. Dr. Fierrenzo Omaneto is a biomedical engineer and director of this silk lab at Tufts University in Massachusetts. Thanks for joining me.

- Thanks for having me. - I wanna thank you Christian for dropping us a line and listeners, if you have a spidey sense about a certain question, you think we can help with, you've served the web, but haven't found an answer

that sticks, give us a ring. We love hearing what you're interested in and we love looking into your questions. Eight, seven, seven, four, sci-fi, eight, seven, seven, four, sci-fi, just leave us a voice mount.

This episode was produced by Rasha O'Ready. I'm Floor Lixman, we'll catch you next time. (upbeat music)