May 28, 2015 • 34 mins
Spider silk is nothing short of an engineering marvel. Weight for weight, it's stronger than steel and tougher than Kevlar. But spiders are disagreeable creatures. Unlike the silkworms, they've proven unwilling to bow to humanity's domestication, but that hasn't stopped scientists from stealing the secrets. In this episode of Stuff to Blow Your Mind, enter a world of spider silk medicine, nanomaterials, optics, music and of course transgenic goats.
Learn more about your ad-choices at https://www.iheartpodcastnetwork.com
See omnystudio.com/listener for privacy information.
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:03):
Welcome to Stuff to Blow your Mind from how Stuff
Works dot com. Hey, welcome to Stuff to Blow your Mind.
My name is Robert Lamb, and I'm Julie Douglas. Julie,
do you remember the myth of a ratney? Oh? Yes,
I do. It's a great one, right, because it follows
a familiar pattern. Right. You begin with a particularly skilled human, right,
(00:28):
a great mortal that has just a wondrous talent at
her disposal. A rackney. She's just a wonderful Weaver's an
expert weaver, just creates these beautiful tapestries, right, puffed up
with pride, I bet, But of course, yeah, In fact,
she ends up boasting of her skills, and either, depending
on what account you're looking at, either she actually challenges Athena,
(00:50):
the Goddess of Wisdom and Crafts, to a weaving competition,
or she just kind of talks about how great she
is and how she's better than Athena until Athena steps
up and uh, you know, and and accepts this challenge.
And of course this is a terrible idea. Right, You're
going up against a god who basically like pick axed
her way out of Zeus's brain, Right, Yeah, and like
(01:12):
all the Greek gods are are are basically terrible. I mean,
they're they're vain, they're petty, they're powerful, and uh, and
yet she ends up in this competition and then it
just gets it gets even worse from there. Um in
Ovid's telling, Athena's resulting tapestry illustrates past incidents where the
gods punished more mortals for their arrogance and uh. And
(01:36):
then Arachne responds by weaving in accounts of just how
massively abusive and just what kind of misleading jerks the
gods are towards humans. So, depending on which account you
look at, either Athena wins because she is a god
and no matter how great your mortal skill, you're gonna
get trump by a god. Or Athena notices that arachney
(02:01):
skill is actually superior to hers, and out of spite
she just kind of rage quits the entire competition. And
in either case she curses Athena and her descendants for
forever turning them into these minuscule web slinging arachnids that
we know and love today. And what is interesting about
(02:21):
that is that in some ways humans are still trying
to extend out this metaphor of trying to manipulate nature
for their own gain or go up against it. So
here's one from way back, and then we'll talk more
recently how we have been trying to do this, all right,
So we have one Francois xavier A ban Sae Hilaire,
(02:45):
who it turns out, took silk and he tried to
do what the gods what nature did, and he tried
to extract it and weave it. And in fact he
took the silk he boiled their cocoons, extracting the threads
with combs to make socks and gloves. And then in
the early nineteenth century along came Jesuit priest Ramondo Maria Tremor,
(03:07):
who discovered that threads extracted from the spider itself produced
a higher quality silk. And there's an eighteen oh seven
engraving showing his extraction device, and we're looking at it
right now. Uh, it kind of looks like a spider guillotine. Yes,
it looks a little nefarious, like I'm instantly sympathizing with
(03:29):
the spider here, Yeah, because you see that its head
is trapped in there in this little half moon device.
It's tiny, and it's abdomen is hanging out, and there's
a winding machine drawing out a continuous strand from it. Yeah,
which instantly makes me think of the paintings of the
windlass of the Rasmus. The spindle that was used to
draw Rasmus is guts out of his body. So it
(03:52):
looks very much like a torture instrument. Yes, true, right
is very nefarious looking, but it's illustrative of the fact
that even with this tiny device, it's incredibly labor intensive.
And while we now have the technology to make this
an easier process, and we have synthetic materials that try
to mimic silk, we humans are still laboring, still pulling
(04:12):
at the strings of silk. But now it's not in
service of our sartorial desires. It's in service of what
we might think of ours, our scientific desires. Yeah. But
still a ragney, she doesn't give up her secrets easily.
She does not. So in this episode, we're going to
talk a bit about what silk is, what spider silk
(04:33):
in particular is, and why it's such a stellar um
engineering feat, and then we're going to talk about the
various ways that that that humans continue to try and
grasp that secret of the silk from the spiders, how
to how we try to mimic it and all the
various uses that we have for it in our modern
(04:53):
scientific world. That's right. And it's not just spiders. The
silkworms so of course, are a huge fixture in this.
That's right because we uh start off by just talking
about what silk is, and in defining silk, we really
need to start more on the insects side of things,
uh than the arachnet. For the most part, silk is
a fine, continuous protein fiber produced by various insect larva
(05:14):
for cocoons, uh. And it's really only produced by a
few groups in the insect world. And we also refer
to silk as a bio polymer now. In insects, silk
originates as a stored protein liquid and modified saliva glands
located in the insect's head. From here it transports via
small tubes to the spinneret structure that protrudes beneath the
(05:38):
mouth parts on the underside of the head of a
given insect. In the case of spiders, however, as we'll discuss,
the spinneret is backloaded on the end of the abdomen
instead uh And we'll get to the spiders in a bit.
But as far as the insects go, the most common
use again is cocooning. That's to contain and protect a
defenseless pupil stage of the insect or and or to
(06:01):
hold it in place on a leaf or a stem,
and also some months build tints out of the material
as well. Cocoon is spun from a single thread of silk.
It might be just pure silk depending on the species,
or it might involve bits of soil or leaf litter
uh that are caught up in the silk strand as well.
(06:21):
So let's look a little closer at the silkworm, which
is the larva or caterpillar of the domesticated silk moth
called bombyx mori, which is Latin for silkworm of the
mulberry tree. In fact, there's a Chinese proverb that says,
with time and patients, the mulberry leaf becomes a silk gown. Now,
the silkworm was once native to China, but now is
(06:42):
completely domesticated. One cocoon consists of a single thread that
is about one thousand to three thousand feet long, that's
three nine hundred meters. And the manipulation of silkworm, the
domestication goes back years. And there's a legend that Lei Zu,
wife of the Yellow Emperor, was drinking tea when a
(07:04):
cocoon fell from a mulberry tree into her steaming cup
of tea and began to unravel. Yes, she was amazed
by its luminosity and strength, and she gathered more and
made silk, and China began to export silk and two
hundred b c e so much so that the Silk Road,
(07:28):
the famous network of trade routes, was created and stretched
from China to the Mediterranean, Africa and Middle East in Europe.
And the origin of silk was really closely guarded, right
because this is the this is the lifeblood of China
at the time. But in five and fifty se some
some wily sly monks who had traveled to China brought
(07:50):
back silkworm eggs, and the end of the West was
forever changed with silk at its disposal. Indeed, now it's
rate as insects. Silk is as great as the silkworm.
Silk is. None of these guys can really match the
arachnids in terms of just pure engineering genius of the thread. Um.
(08:13):
I mean, they're just in a class all their own.
So the thing about the spiders, as we've alluded to,
is that scientists are continuing to study spider silk making
and UH and trying to get all the valuable details
out of it. And we still have a lot of
questions regarding exactly how it all comes together. UM. But
here the basics as we understand it. Spiders, like the
(08:35):
like insects, um like the silkworms, have a special special
glands to secrete silk proteins dissolved in a water based solution.
The spider pushes the liquid solution through long ducts, leading
to microscopic UH bigots on the spiders spinnerets, and generally
there are two or three spinneret pairs located in the
rear of the admin. Furthermore, each spigot has a valve
(08:57):
that controls the thickness and speed of the extruded material.
So already we're seeing like these different layers of complexity
that are in play when it comes to just pushing
out that that layer of silk. I think it's easy
to fall into the trap of thinking of spider silk
as kind of like silly string, right, Like there's just
a gland, they squeeze it out, and they just squeeze
(09:18):
out this thread, and yes, there's some sort of a
you know, a hardening of the liquid as it comes out,
but we think, well, there's nothing more to that. But
really we're talking about a really intense engineering feet just
at the the construction of the material itself. As the
spigots pull these silk molecules out of the ducks and
excrewed them and extrude them into the air, the molecules
(09:39):
are stretched out and linked together to form long strands,
and then the spinnerettes wind the strands together to form
the sturdy silk fiber itself. And this is where it
gets even crazier, because most spiders have multiple silk glands
in their body, which secrete different types of silk material
optimized for different purposes. By winding different silk varieties together
(10:02):
in varying proportions, uh, spiders can form a wide range
of fiber material. So it's not just one type of
ciders a spider silk that's coming out. There are varying
spider silks depending on what their purposes. They can vary
fiber consistency by adjusting the spigots from smaller to larger strands,
and sometimes they'll create a silk strand consisting of an
(10:22):
inner core with an outer tube around it. Uh, And
they might apply various coatings such as a waterproof coating
or a sticky layer, depending on what the use is.
So so again, when it comes to spider silk, when
they're creating it, that the purpose of the silk is
reflected in the actual construction of the silk thread itself,
(10:44):
which is amazing, especially if you bump this up against
the silkworm and nothing against the silkworm. They're doing a
pretty cool job there with making their cocoon, right, But
that's sort of like, here's this one thing I can do,
whereas a spider is more like its own three D
printer exactly. I think that's a fabulous comparison. Yeah, I mean,
it's varying the type of product that it's creating. And
(11:06):
the best way to really examine this is to look
at the anatomy of a web, because I remember, above
all else, spiders are predators, and so they've come up
with this elaborate way to catch their dinners. Now, they
will initially just cast a silk line out into the wind,
and when it senses that it's caught upon something, it
will cinch a starting point and use that connection as
(11:28):
a bridge, walking across it as it creates a loose
silk hanging from the starting and ending points of this
bridge is created, so at that point it pulls pulls
down the silk time. It creates a kind of y configuration.
It then creates anchor points and structural threads, laying out
radius points from the center of the web of the threads.
(11:49):
So then you have the various different types of thread
being spun. Here, you have a non stick auxiliary spiral
that's created as well as a second stick auxiliary one,
so the spider has its own smooth path to tread
upon while ensuring that the web is good and sticky elsewhere.
And there are various I mean, there are tons of
(12:13):
different types of webs and dizzying and their complexity. Right,
they're beautiful to look at. But one that I wanted
to point out is not even functioning as a true web,
and this is via trapdoor spiders who use their webs
in a really ingenious way. First they dig a tunnel,
which they smooth out with a mixture of saliva and earth.
(12:36):
Then they fit the opening to the tunnel with a
trap door, and it's made out of spider silk, and
it can be fitted exactly to the dimensions with a
beveled edge like that's craftsmanship, or it can just have
a sheet of silk and dirt, and then the top
of the trapdoors tricked out with debris so that it
easily blends in. So this tunnel gives the spider refuge.
(12:56):
It also gives them a place to raise their young
end and also in the background, serves as this device
to let the spider know that, you know, there's prey around.
And it does this that trapdoor by vibrating, and once
the spider detects that, it can easily rush out, pull
(13:17):
in that prey into its hole and then chomp on it.
And it's kind of we were talking about it earlier.
I was like, Hey, I'm a little bit I kind
of don't want to necessarily put this upon the spiders
trapped or spider, but it feels a little bit serial
killer to me. Yeah, I mean that that's kind of
the vibe of the spider right now. As you mentioned,
their various uses for the silk material, various structures that
(13:41):
are created by the spiders, and we discussed some of
those in our episode It's a Trap, which will include
a link to on the landing page for this episode.
But these structures are amazing, and the level of engineering
is is evident not only in the structure of the
that they create out of the webbing, it again in
the uh, the minute structure of the strands themselves. Uh.
(14:05):
Spider silk is is is particularly great engineering substance because
it's incredibly strong, but it's also incredibly flexible. Uh. There's
some varieties that are reportedly five times as strong as
an equal mass of steel and twice as strong as
an equal mass of kevlar. So again, it rivals some
of our key tough materials that we as humans wield
(14:29):
in the world around us. Now, to understand, you know,
why it's so strong, we have to look at the
molecular construction of spider silk itself. According to a two
thousand eight study from M I. T. The strength lies
in the specific geometric configuration of structural proteins, which have
small clusters of weak hydrogen bonds that work cooperatively to
(14:51):
resist force and dissipate energy. Two twelve University of California
Riverside study identified the genes and determine the DNA sequence
for two key proteins in the drag line silk of
the black widow spider. And and you often see the
drag line silk is a focused point UH in the
various studies because of the services the bridge, it has
to be really strong. So this is the primo material
(15:14):
when it comes to spider silk UH. And it turns
out the straight drag line silk is a composite material
comprised of two different proteins, each containing three regions with
distinct properties. So you have an amorphous non crystalline matrix
that's stretchable, giving the silk elasticity. And then embedded in
the amorphous portions of both proteins are two kinds of
(15:35):
crystalline regions that toughen the silk. So the resulting composite
is strong, tough, yet elastic. And and again it's it's
there and just the minute construction of the thread itself,
and we humans see it, we admire it, and we
want it. But commercial production of spider silk from spiders
(15:56):
is impractical because spiders are jerks right there. They're to
cannibalistic and territorial for farming. They're not really jerks, but
you know, they're just not ideal for that purpose. Uh
And researchers have looked to other organisms, including bacteria, insects, mammals,
and plants, But those proteins require mechanical spinning and this
(16:17):
is a task that our friend the silkworm performs naturally
with those nifty spinneretts. So so what's the researcher to do. Well,
let's look at Malcolm Fraser Jr. Who in two thousand
and twelve with his team created a hybrid silkworm to
do their bidding, one with both silkworm and spider silk proteins,
(16:40):
and results showed that taking these two proteins um would
result any tougher than typical silkworm silk. It would be
as tough as drag line silk um and it would
be just the right material that you would want to
try to commercially produce. So why would you do this?
Why would you mercially produce it um? We'll discuss other
(17:03):
instances in which you can use it. But when they
were looking at for this purpose, it was for wound dressings,
artificial ligments, tendons, tissue scaffolds, micro capsules, cosmetics, and textiles. Okay, Now,
while some of you have probably heard of these transgenic
silk worms, I bet even more of you remember the
transgenic spider goat hybrid, because this really made the rounds,
(17:26):
especially back in two thousand two. Uh, instantly bringing to
mind and uh and probably to digital reality. Poorly photoshopped
images of a goat with like big spider legs coming
out of its side, right, was photoshopped? Yeah, because because
the real transgenic goat spider hybrid just looks like a goat. Um.
This again, it's happening back in two thousand two, researchers
(17:47):
at Nexia Biotechnologies genetically modified goats using silk producing genes
from spiders, which just a headline level back in two
thousand two, it of course instantly sounds Frankensteiny, right, like
who are these scientists and why are they trying to
make goat spiders? Um. But at this point in the podcast,
(18:08):
I think everyone understands what they were going for the
idea was that you would have a small number of
goats that would be able to produce a large amount
of silk material in their milk, which could then be
used in various UH then could be utilized for various
purposes as we'll discuss. Essentially, they would be the goats
will be creating dragline milk. Now, the strands that they
(18:30):
produced were only as strong as natural spider silk, but
still it's a start, right UH and and at their
height next to as Montreal Flock had nearly fifty spider
goats total. But the company went bankrupt in two thousand nine,
So you had a couple of transgendent goats that went
to the Canadian Agricultural Museum, while the rest of them
(18:52):
went to Utah State University where they're continue to study
them to this day and figure out how we can
best utilize a spider goat UM for the for the
better men of humanity. Now, that's not the only instance
of a company either going bankrupt or just pulling out
of the endeavor entirely. And that is because even though
you you have UM information being uncovered and you have
(19:17):
the transgenic UH, the ability to mess around with this
and try to do this in other organisms you still
have to understand the relationship between spider silk structure and
its function. And again a lot of companies have tried
to do this, but it wasn't until researchers from Dalhousie
University in Nova Scotia took a closer look at the
(19:38):
mechanism and tried to uncover some piece of information that
might get them a little bit closer. Now, the first
step is that they created artificial spider silk to replicate
the proteins that make up the natural version, in this
case by recombinantly expressing them in the Bacterium E coli. Now,
they looked at the key protein and acid informed silk
(20:00):
called a c sp one and they said, okay, it's
got three parts. And they said, all right. The protein,
most of it is repeated sequences of about two hundred
amino acids, and there are two tales called the N
and C terminal domains that hang off each end of
the protein chain. Now, when they took these proteins and
they chained them together, they found that the chains weren't
(20:22):
working in unison, but rather as independent units. So that
was the first clue of how these are actually working
within spiders. And it was the C terminal domain of
the protein that was the juncture of the protein that
determined the strength of the fiber. So when you're talking
about that spider being in the architect and choosing a
different type of that type of material, but maybe um
(20:44):
consistency or strength, that's the C terminal that is controlling that.
And this was a huge breakthrough, right because it peeled
away a layer of mystery, and yet there's still so
much to be learned in the evolution of spider silk. Yeah,
because then we what do you do with that data?
(21:04):
Then it just leads to six other questions regarding the
engineering process that's taking place there. I guess what you
knew is you look at it in its in its
form right now and say, oh, what can we deal
with it? Right? And that's really the the examples we're
gonna look to next in the podcast are really looking
more at at possible uh ways that we can use
the spider silk and the structure of the spider silk
(21:27):
and in some cases of the structure of the web itself,
how we can mimic that design in various pursuits. According
to a two thousand fourteen paper from the University of
Akron UH spider silk could be used as an inspiration
to create more efficient and stronger commercial and biomedical adhesives
that could, for example, potentially attach tendons to bones, bind fractures, etcetera.
(21:50):
Anytime you need to bring to shoot together and hold
it in place firmly. And and of course one of
the advantages here is we'd be using a biosubstance as
opposed to something that has to be ejected from the
body or taken out at a later date. UH. In particular,
with this particular with this study, UH, they were looking
at the attachment disks that spiders used to attach their
(22:12):
webs to structure. So the spider pins down an underlying
thread of silk with additional threads like stitches or staples
on top of it. UM. But the real engineering feed
here is that the geometry of the attachment disk, the
way that they're actually laying down these strands, it creates
a super strong attachment force using very little material. So
(22:34):
it's you know, a perfect economic model to try and
and mimic. So this this particular team led by you
a professor of polymer science, Ali Dinawala, utilized electro spinning
to mimic the efficient staple pin method. Now, electro spinning
is a process by which an electrical charge is used
(22:55):
to draw very fine fibers from a liquid. And in
the case of this, uh, this particular experiment, they were
using polyure thing. Okay, So again, the possible uses here
include you know binding, uh, you know, tendons back together, binding,
tends to bone, binding, fractures, etcetera. And you'd be using
material that can degrade and be reabsorbed by the body.
(23:17):
Now that's an example of mending the human body. But
spider silk also shows up when you're talking about essentially
growing new organs for yourself. And that's because you need
when you're talking about growing artificial tissues and organs, you
need some kind of structure or substrate for the entity
to grow around. And so what could be feather light
(23:40):
but formidable enough to provide a framework spiderwebs, of course.
So you have a group of researchers led by Professor
Constantine A. Glad Say, who heads the Laboratory of Biophysics
of Excitable Systems m I p T, and they work
specifically on cardiac tissues. Isolate, a protein used in web
(24:01):
spinning called spiedroying. What they did is they seated isolated
neonatal rat cardiac cells on fiber matrices and during the experiment,
the researchers monitored the growth of the cells and they
tested their contractability right in their ability to conduct electrical impulses,
and these are the main features of normal cardiac tissue.
(24:23):
They wanted to see if that could be mimicked in
in the protein. And the monitoring, which was carried out
with the help of a microscope and fluorescent markers, showed
that within three to five days a layer of cells
formed on the substrate that we're able to contract synchronously
and conduct electrical impulses, just like the tissue of a
(24:46):
living heartwood. And this is pretty big news, right. It
doesn't mean that we're around the corner from grow your
replacement heart clinics um, but it does mean that it's
it's a serious step toward me a beating heart out
of a few cells, Like that's going to become an
eventual reality. And now you found the material. That's just
(25:08):
one more in the link to it. It's sounding more
and more like the bodies of the future will just
be riddled with spider self and I have another example
of it here. Uh. I mean, this one really kind
of blew me away because the example, if we looked
at so far that they're they're based in structure, right,
We're looking at the structure of the webbing and how
it can be used to make attachments, to to create
(25:29):
a structure, to grow tissue over, etcetera. But there were
a couple of studies that came out in a two
thousand twelve edition of Researchers at Frontiers and Optics, a
scientific journal. UH looked at two independent teams, one at
TUF University in Boston at one at c n R.
S Institute of Physics in France. UH, and they were
looking at ways that this natural spider silk could be
(25:52):
used as an eco friendly alternative two traditional methods of
manipulating light. So we're talking about, um, an alternative to
glass or plastic fiber optics and lenses. UM. Why would
you want this again? It comes back to biomedical technology, right,
the placement of sensors and tags or any kind of
(26:15):
utilized utilization of light within the human body. UM. I
mean the revelation for me here that I just did
not realize was that as it turns out, in addition
to being super sturdy and flexible, silk is a gifted
light manipulator, and so so light could travel through silk
almost as easily as it flows through through glass fibers.
(26:37):
So the potential here hits two key areas. One implanable
biodegradable optics utilized in sensors and tags that are placed
inside the body. We've talked about the the importance of
real time monitoring um of of our of our body
and how that is that can play into better management
of our overall health. And another area is that you
(26:59):
can take this on biosensors. You can take a pristine
fiber of spider silk and carry light into the body
through a very small opening um which would be quite
useful for internal imaging or even chemical diagnosis using spectroscopy,
which is the analysis of matter based on its interaction
with light. So yeah, just it's amazing to think of this,
(27:22):
like this tiny little thread of of of spider silk
going in through a tiny hole in the body and
aiding in the in diagnosis. That really, to me is like,
I think, a game changer and amazing to me that
the material is being used that way. Yeah, it just again,
it just it just drives home just how impressive this
(27:42):
material is. Yeah, and again, just to underscore that uh
impressive durability and strength, let's go back to the spider's
drag line again. It is the stuff of engineer's streams,
the tensile strength of a high grade alloy steel, while
being a sixth as dense and incredibly flexible. You can
(28:03):
draw it out about five times at some length without
compromising it. So how do you get a spider to
do better? How do you ask it to just up
its game of kevlar strength? Okay, we're still trying to
actually steal its secrets, but then we're also saying what
can we do to bump it up? Yeah, we're saying, hey,
we know you've perfected this over four hundred million years
(28:25):
of evolution, but do you think right now you could
do something to increase the durability. Well, of course we're
talking about here is some researchers. In this case, we're
talking about Nicola Puno at the University of Trento in
Italy and his team who took some seller spiders who
are also known as fulsit I and the site spider
(28:48):
Hugger dot com by the way, describes these spiders as
quote looking like something made out of many marshmallows of
pipe cleaners. So the research took these seller spiders and
they douse the spiders with either water containing carbon nanotubes
or graphine flakes. Now two materials that are both really
really strong, right, So this is an attempt to sort
(29:10):
of to supersize the strength of the of the spider
and sort of make it into it's a little spider superhero.
They checked out the spider's handiwork after they did this
for each strand of silk, and they fixed the fiber
between two C shaped cardboard holders and placed it in
a device that can measure the load on a fiber
(29:31):
with a resolution of fifteen nanomutants in any fiber displacement
with a resolution of a point one nanometers. Okay, So,
in other words, are very serious about the tin sile
strength here, and Pina wrote that the thread is the
highest toughness modulus for a fiber, surpassing synthetic polymeric high
performance fibers like Kevlar forty nine and even the current
(29:53):
toughest knotted fibers. So it was amazing about that is
not only it was the thread tougher than before, right,
tougher than kevlar, tougher than its own natural tensile strength.
But they could find the actual carbon nanitubes in it.
They just weren't sure of how it was happening. At first.
(30:16):
They thought, well, maybe they were taking it and spreading
it onto the spider silk after it came out of them,
but that was discounted. They're just not sure how it
was incorporated into their bodies to create it. So again
we find out a little more about the mystery of
spider silk, and we just end up with more questions.
It is the great mystery. Well you know, um, we
(30:38):
have one more study to to mention here, and and
this one we feel really really drives home the elegance
of the design that we see here again not only
in the structure that they build, but the but the
material that they build in the varying take some material
they build to construct it. The comparison here spy eighter
(31:00):
silk and music spidered web and U and you know,
a classically arranged piece of music. Um. In particularly, we're
looking at a study from two thousand eleven researches at M. I. T.
They created a scientifically rigorous analogy that shows the similarities
between the physical structure structure of spider silk and the
(31:22):
sonic structure of a melody. Um and taking it down,
just stripping it down to the building blocks of either
an amino acid in the case of the webbing, and
a sound wave in the case of the music. Yeah.
And it's got many different layers of sound in music
to it in this analogy, and the study explains that
(31:43):
structural patterns are directly related to the functional properties. That's
one layer of lightweight strength in the spider silk and
in the riff sonic tension that creates an emotional response
in the listener. It's interesting to think of actually melody
music is spider webs, right, and the tension that's held
within them and the structures, the repeating patterns. Yeah, it
(32:05):
just again it drives home just the elegance of the
design and just how how nuanced it is. Um. I
don't know if I'm going to start thinking of music
I like as a spider web exactly, but but but
it's it's it's a wonderful analogy that they make and
back up with data. Yeah, it's another way to look
(32:28):
at um, not Fibonacci, but symmetry and nature and the
patterns held within and only that uh, the communication, right,
because if you think about the spider web and the
vibrations that it's giving off, that perhaps is a kind
of melody to the spider itself telling it something about
(32:48):
the pacing, something about the beat of the thing that's
making it vibrate. Yeah, the sweet sweet music of of
of a creature in agony wrapped up in your web
that you could take. I'll go and uh and wrap
up some more and drain the life force from that exactly.
That's the song of the spider right there, all right.
(33:10):
So there you have it, uh, spider silk. I hope
that uh, I hope that that that you guys and
guys listening have more respect now for the spider and
what it's doing. It's not just a silly string coming
out of a spiders but it's uh, and it's not
you know, spiderweb itself is not on par with just
you know, doing some cat's cradle stuff with some string
(33:30):
and your fingers. That it's an engineering marvel at every level.
If you would like to learn more about this topic
and others, that'll be sure to head on over stuff
to Blow your Mind dot com. There's where you'll find
uh podcast videos, blog post links out of social media accounts,
and we'll make sure that we have stuff on the
landing page linking out to some wonderful resources, including the
(33:50):
how spiders Work article on how stuff works dot com,
which gives you a wonderful overview of spider anatomy. If
you have thoughts about the culture or residents of silkworms
in China, or if you have thoughts about spider webs
and silk used in biomedicine, particularly in your own body,
or even what we're talking about with melodies and the
(34:13):
patterns of spider webs, please do share those thoughts with us.
We'd love to hear from you, and you can email
us at blow the Mind House to works dot com
for more on this and thousands of other topics. Is
it how staff works dot com
Welcome to Stuff to Blow your Mind from how Stuff
Works dot com. Hey, welcome to Stuff to Blow your Mind.
My name is Robert Lamb, and I'm Julie Douglas. Julie,
do you remember the myth of a ratney? Oh? Yes,
I do. It's a great one, right, because it follows
a familiar pattern. Right. You begin with a particularly skilled human, right,
(00:28):
a great mortal that has just a wondrous talent at
her disposal. A rackney. She's just a wonderful Weaver's an
expert weaver, just creates these beautiful tapestries, right, puffed up
with pride, I bet, But of course, yeah, In fact,
she ends up boasting of her skills, and either, depending
on what account you're looking at, either she actually challenges Athena,
(00:50):
the Goddess of Wisdom and Crafts, to a weaving competition,
or she just kind of talks about how great she
is and how she's better than Athena until Athena steps
up and uh, you know, and and accepts this challenge.
And of course this is a terrible idea. Right, You're
going up against a god who basically like pick axed
her way out of Zeus's brain, Right, Yeah, and like
(01:12):
all the Greek gods are are are basically terrible. I mean,
they're they're vain, they're petty, they're powerful, and uh, and
yet she ends up in this competition and then it
just gets it gets even worse from there. Um in
Ovid's telling, Athena's resulting tapestry illustrates past incidents where the
gods punished more mortals for their arrogance and uh. And
(01:36):
then Arachne responds by weaving in accounts of just how
massively abusive and just what kind of misleading jerks the
gods are towards humans. So, depending on which account you
look at, either Athena wins because she is a god
and no matter how great your mortal skill, you're gonna
get trump by a god. Or Athena notices that arachney
(02:01):
skill is actually superior to hers, and out of spite
she just kind of rage quits the entire competition. And
in either case she curses Athena and her descendants for
forever turning them into these minuscule web slinging arachnids that
we know and love today. And what is interesting about
(02:21):
that is that in some ways humans are still trying
to extend out this metaphor of trying to manipulate nature
for their own gain or go up against it. So
here's one from way back, and then we'll talk more
recently how we have been trying to do this, all right,
So we have one Francois xavier A ban Sae Hilaire,
(02:45):
who it turns out, took silk and he tried to
do what the gods what nature did, and he tried
to extract it and weave it. And in fact he
took the silk he boiled their cocoons, extracting the threads
with combs to make socks and gloves. And then in
the early nineteenth century along came Jesuit priest Ramondo Maria Tremor,
(03:07):
who discovered that threads extracted from the spider itself produced
a higher quality silk. And there's an eighteen oh seven
engraving showing his extraction device, and we're looking at it
right now. Uh, it kind of looks like a spider guillotine. Yes,
it looks a little nefarious, like I'm instantly sympathizing with
(03:29):
the spider here, Yeah, because you see that its head
is trapped in there in this little half moon device.
It's tiny, and it's abdomen is hanging out, and there's
a winding machine drawing out a continuous strand from it. Yeah,
which instantly makes me think of the paintings of the
windlass of the Rasmus. The spindle that was used to
draw Rasmus is guts out of his body. So it
(03:52):
looks very much like a torture instrument. Yes, true, right
is very nefarious looking, but it's illustrative of the fact
that even with this tiny device, it's incredibly labor intensive.
And while we now have the technology to make this
an easier process, and we have synthetic materials that try
to mimic silk, we humans are still laboring, still pulling
(04:12):
at the strings of silk. But now it's not in
service of our sartorial desires. It's in service of what
we might think of ours, our scientific desires. Yeah. But
still a ragney, she doesn't give up her secrets easily.
She does not. So in this episode, we're going to
talk a bit about what silk is, what spider silk
(04:33):
in particular is, and why it's such a stellar um
engineering feat, and then we're going to talk about the
various ways that that that humans continue to try and
grasp that secret of the silk from the spiders, how
to how we try to mimic it and all the
various uses that we have for it in our modern
(04:53):
scientific world. That's right. And it's not just spiders. The
silkworms so of course, are a huge fixture in this.
That's right because we uh start off by just talking
about what silk is, and in defining silk, we really
need to start more on the insects side of things,
uh than the arachnet. For the most part, silk is
a fine, continuous protein fiber produced by various insect larva
(05:14):
for cocoons, uh. And it's really only produced by a
few groups in the insect world. And we also refer
to silk as a bio polymer now. In insects, silk
originates as a stored protein liquid and modified saliva glands
located in the insect's head. From here it transports via
small tubes to the spinneret structure that protrudes beneath the
(05:38):
mouth parts on the underside of the head of a
given insect. In the case of spiders, however, as we'll discuss,
the spinneret is backloaded on the end of the abdomen
instead uh And we'll get to the spiders in a bit.
But as far as the insects go, the most common
use again is cocooning. That's to contain and protect a
defenseless pupil stage of the insect or and or to
(06:01):
hold it in place on a leaf or a stem,
and also some months build tints out of the material
as well. Cocoon is spun from a single thread of silk.
It might be just pure silk depending on the species,
or it might involve bits of soil or leaf litter
uh that are caught up in the silk strand as well.
(06:21):
So let's look a little closer at the silkworm, which
is the larva or caterpillar of the domesticated silk moth
called bombyx mori, which is Latin for silkworm of the
mulberry tree. In fact, there's a Chinese proverb that says,
with time and patients, the mulberry leaf becomes a silk gown. Now,
the silkworm was once native to China, but now is
(06:42):
completely domesticated. One cocoon consists of a single thread that
is about one thousand to three thousand feet long, that's
three nine hundred meters. And the manipulation of silkworm, the
domestication goes back years. And there's a legend that Lei Zu,
wife of the Yellow Emperor, was drinking tea when a
(07:04):
cocoon fell from a mulberry tree into her steaming cup
of tea and began to unravel. Yes, she was amazed
by its luminosity and strength, and she gathered more and
made silk, and China began to export silk and two
hundred b c e so much so that the Silk Road,
(07:28):
the famous network of trade routes, was created and stretched
from China to the Mediterranean, Africa and Middle East in Europe.
And the origin of silk was really closely guarded, right
because this is the this is the lifeblood of China
at the time. But in five and fifty se some
some wily sly monks who had traveled to China brought
(07:50):
back silkworm eggs, and the end of the West was
forever changed with silk at its disposal. Indeed, now it's
rate as insects. Silk is as great as the silkworm.
Silk is. None of these guys can really match the
arachnids in terms of just pure engineering genius of the thread. Um.
(08:13):
I mean, they're just in a class all their own.
So the thing about the spiders, as we've alluded to,
is that scientists are continuing to study spider silk making
and UH and trying to get all the valuable details
out of it. And we still have a lot of
questions regarding exactly how it all comes together. UM. But
here the basics as we understand it. Spiders, like the
(08:35):
like insects, um like the silkworms, have a special special
glands to secrete silk proteins dissolved in a water based solution.
The spider pushes the liquid solution through long ducts, leading
to microscopic UH bigots on the spiders spinnerets, and generally
there are two or three spinneret pairs located in the
rear of the admin. Furthermore, each spigot has a valve
(08:57):
that controls the thickness and speed of the extruded material.
So already we're seeing like these different layers of complexity
that are in play when it comes to just pushing
out that that layer of silk. I think it's easy
to fall into the trap of thinking of spider silk
as kind of like silly string, right, Like there's just
a gland, they squeeze it out, and they just squeeze
(09:18):
out this thread, and yes, there's some sort of a
you know, a hardening of the liquid as it comes out,
but we think, well, there's nothing more to that. But
really we're talking about a really intense engineering feet just
at the the construction of the material itself. As the
spigots pull these silk molecules out of the ducks and
excrewed them and extrude them into the air, the molecules
(09:39):
are stretched out and linked together to form long strands,
and then the spinnerettes wind the strands together to form
the sturdy silk fiber itself. And this is where it
gets even crazier, because most spiders have multiple silk glands
in their body, which secrete different types of silk material
optimized for different purposes. By winding different silk varieties together
(10:02):
in varying proportions, uh, spiders can form a wide range
of fiber material. So it's not just one type of
ciders a spider silk that's coming out. There are varying
spider silks depending on what their purposes. They can vary
fiber consistency by adjusting the spigots from smaller to larger strands,
and sometimes they'll create a silk strand consisting of an
(10:22):
inner core with an outer tube around it. Uh, And
they might apply various coatings such as a waterproof coating
or a sticky layer, depending on what the use is.
So so again, when it comes to spider silk, when
they're creating it, that the purpose of the silk is
reflected in the actual construction of the silk thread itself,
(10:44):
which is amazing, especially if you bump this up against
the silkworm and nothing against the silkworm. They're doing a
pretty cool job there with making their cocoon, right, But
that's sort of like, here's this one thing I can do,
whereas a spider is more like its own three D
printer exactly. I think that's a fabulous comparison. Yeah, I mean,
it's varying the type of product that it's creating. And
(11:06):
the best way to really examine this is to look
at the anatomy of a web, because I remember, above
all else, spiders are predators, and so they've come up
with this elaborate way to catch their dinners. Now, they
will initially just cast a silk line out into the wind,
and when it senses that it's caught upon something, it
will cinch a starting point and use that connection as
(11:28):
a bridge, walking across it as it creates a loose
silk hanging from the starting and ending points of this
bridge is created, so at that point it pulls pulls
down the silk time. It creates a kind of y configuration.
It then creates anchor points and structural threads, laying out
radius points from the center of the web of the threads.
(11:49):
So then you have the various different types of thread
being spun. Here, you have a non stick auxiliary spiral
that's created as well as a second stick auxiliary one,
so the spider has its own smooth path to tread
upon while ensuring that the web is good and sticky elsewhere.
And there are various I mean, there are tons of
(12:13):
different types of webs and dizzying and their complexity. Right,
they're beautiful to look at. But one that I wanted
to point out is not even functioning as a true web,
and this is via trapdoor spiders who use their webs
in a really ingenious way. First they dig a tunnel,
which they smooth out with a mixture of saliva and earth.
(12:36):
Then they fit the opening to the tunnel with a
trap door, and it's made out of spider silk, and
it can be fitted exactly to the dimensions with a
beveled edge like that's craftsmanship, or it can just have
a sheet of silk and dirt, and then the top
of the trapdoors tricked out with debris so that it
easily blends in. So this tunnel gives the spider refuge.
(12:56):
It also gives them a place to raise their young
end and also in the background, serves as this device
to let the spider know that, you know, there's prey around.
And it does this that trapdoor by vibrating, and once
the spider detects that, it can easily rush out, pull
(13:17):
in that prey into its hole and then chomp on it.
And it's kind of we were talking about it earlier.
I was like, Hey, I'm a little bit I kind
of don't want to necessarily put this upon the spiders
trapped or spider, but it feels a little bit serial
killer to me. Yeah, I mean that that's kind of
the vibe of the spider right now. As you mentioned,
their various uses for the silk material, various structures that
(13:41):
are created by the spiders, and we discussed some of
those in our episode It's a Trap, which will include
a link to on the landing page for this episode.
But these structures are amazing, and the level of engineering
is is evident not only in the structure of the
that they create out of the webbing, it again in
the uh, the minute structure of the strands themselves. Uh.
(14:05):
Spider silk is is is particularly great engineering substance because
it's incredibly strong, but it's also incredibly flexible. Uh. There's
some varieties that are reportedly five times as strong as
an equal mass of steel and twice as strong as
an equal mass of kevlar. So again, it rivals some
of our key tough materials that we as humans wield
(14:29):
in the world around us. Now, to understand, you know,
why it's so strong, we have to look at the
molecular construction of spider silk itself. According to a two
thousand eight study from M I. T. The strength lies
in the specific geometric configuration of structural proteins, which have
small clusters of weak hydrogen bonds that work cooperatively to
(14:51):
resist force and dissipate energy. Two twelve University of California
Riverside study identified the genes and determine the DNA sequence
for two key proteins in the drag line silk of
the black widow spider. And and you often see the
drag line silk is a focused point UH in the
various studies because of the services the bridge, it has
to be really strong. So this is the primo material
(15:14):
when it comes to spider silk UH. And it turns
out the straight drag line silk is a composite material
comprised of two different proteins, each containing three regions with
distinct properties. So you have an amorphous non crystalline matrix
that's stretchable, giving the silk elasticity. And then embedded in
the amorphous portions of both proteins are two kinds of
(15:35):
crystalline regions that toughen the silk. So the resulting composite
is strong, tough, yet elastic. And and again it's it's
there and just the minute construction of the thread itself,
and we humans see it, we admire it, and we
want it. But commercial production of spider silk from spiders
(15:56):
is impractical because spiders are jerks right there. They're to
cannibalistic and territorial for farming. They're not really jerks, but
you know, they're just not ideal for that purpose. Uh
And researchers have looked to other organisms, including bacteria, insects, mammals,
and plants, But those proteins require mechanical spinning and this
(16:17):
is a task that our friend the silkworm performs naturally
with those nifty spinneretts. So so what's the researcher to do. Well,
let's look at Malcolm Fraser Jr. Who in two thousand
and twelve with his team created a hybrid silkworm to
do their bidding, one with both silkworm and spider silk proteins,
(16:40):
and results showed that taking these two proteins um would
result any tougher than typical silkworm silk. It would be
as tough as drag line silk um and it would
be just the right material that you would want to
try to commercially produce. So why would you do this?
Why would you mercially produce it um? We'll discuss other
(17:03):
instances in which you can use it. But when they
were looking at for this purpose, it was for wound dressings,
artificial ligments, tendons, tissue scaffolds, micro capsules, cosmetics, and textiles. Okay, Now,
while some of you have probably heard of these transgenic
silk worms, I bet even more of you remember the
transgenic spider goat hybrid, because this really made the rounds,
(17:26):
especially back in two thousand two. Uh, instantly bringing to
mind and uh and probably to digital reality. Poorly photoshopped
images of a goat with like big spider legs coming
out of its side, right, was photoshopped? Yeah, because because
the real transgenic goat spider hybrid just looks like a goat. Um.
This again, it's happening back in two thousand two, researchers
(17:47):
at Nexia Biotechnologies genetically modified goats using silk producing genes
from spiders, which just a headline level back in two
thousand two, it of course instantly sounds Frankensteiny, right, like
who are these scientists and why are they trying to
make goat spiders? Um. But at this point in the podcast,
(18:08):
I think everyone understands what they were going for the
idea was that you would have a small number of
goats that would be able to produce a large amount
of silk material in their milk, which could then be
used in various UH then could be utilized for various
purposes as we'll discuss. Essentially, they would be the goats
will be creating dragline milk. Now, the strands that they
(18:30):
produced were only as strong as natural spider silk, but
still it's a start, right UH and and at their
height next to as Montreal Flock had nearly fifty spider
goats total. But the company went bankrupt in two thousand nine,
So you had a couple of transgendent goats that went
to the Canadian Agricultural Museum, while the rest of them
(18:52):
went to Utah State University where they're continue to study
them to this day and figure out how we can
best utilize a spider goat UM for the for the
better men of humanity. Now, that's not the only instance
of a company either going bankrupt or just pulling out
of the endeavor entirely. And that is because even though
you you have UM information being uncovered and you have
(19:17):
the transgenic UH, the ability to mess around with this
and try to do this in other organisms you still
have to understand the relationship between spider silk structure and
its function. And again a lot of companies have tried
to do this, but it wasn't until researchers from Dalhousie
University in Nova Scotia took a closer look at the
(19:38):
mechanism and tried to uncover some piece of information that
might get them a little bit closer. Now, the first
step is that they created artificial spider silk to replicate
the proteins that make up the natural version, in this
case by recombinantly expressing them in the Bacterium E coli. Now,
they looked at the key protein and acid informed silk
(20:00):
called a c sp one and they said, okay, it's
got three parts. And they said, all right. The protein,
most of it is repeated sequences of about two hundred
amino acids, and there are two tales called the N
and C terminal domains that hang off each end of
the protein chain. Now, when they took these proteins and
they chained them together, they found that the chains weren't
(20:22):
working in unison, but rather as independent units. So that
was the first clue of how these are actually working
within spiders. And it was the C terminal domain of
the protein that was the juncture of the protein that
determined the strength of the fiber. So when you're talking
about that spider being in the architect and choosing a
different type of that type of material, but maybe um
(20:44):
consistency or strength, that's the C terminal that is controlling that.
And this was a huge breakthrough, right because it peeled
away a layer of mystery, and yet there's still so
much to be learned in the evolution of spider silk. Yeah,
because then we what do you do with that data?
(21:04):
Then it just leads to six other questions regarding the
engineering process that's taking place there. I guess what you
knew is you look at it in its in its
form right now and say, oh, what can we deal
with it? Right? And that's really the the examples we're
gonna look to next in the podcast are really looking
more at at possible uh ways that we can use
the spider silk and the structure of the spider silk
(21:27):
and in some cases of the structure of the web itself,
how we can mimic that design in various pursuits. According
to a two thousand fourteen paper from the University of
Akron UH spider silk could be used as an inspiration
to create more efficient and stronger commercial and biomedical adhesives
that could, for example, potentially attach tendons to bones, bind fractures, etcetera.
(21:50):
Anytime you need to bring to shoot together and hold
it in place firmly. And and of course one of
the advantages here is we'd be using a biosubstance as
opposed to something that has to be ejected from the
body or taken out at a later date. UH. In particular,
with this particular with this study, UH, they were looking
at the attachment disks that spiders used to attach their
(22:12):
webs to structure. So the spider pins down an underlying
thread of silk with additional threads like stitches or staples
on top of it. UM. But the real engineering feed
here is that the geometry of the attachment disk, the
way that they're actually laying down these strands, it creates
a super strong attachment force using very little material. So
(22:34):
it's you know, a perfect economic model to try and
and mimic. So this this particular team led by you
a professor of polymer science, Ali Dinawala, utilized electro spinning
to mimic the efficient staple pin method. Now, electro spinning
is a process by which an electrical charge is used
(22:55):
to draw very fine fibers from a liquid. And in
the case of this, uh, this particular experiment, they were
using polyure thing. Okay, So again, the possible uses here
include you know binding, uh, you know, tendons back together, binding,
tends to bone, binding, fractures, etcetera. And you'd be using
material that can degrade and be reabsorbed by the body.
(23:17):
Now that's an example of mending the human body. But
spider silk also shows up when you're talking about essentially
growing new organs for yourself. And that's because you need
when you're talking about growing artificial tissues and organs, you
need some kind of structure or substrate for the entity
to grow around. And so what could be feather light
(23:40):
but formidable enough to provide a framework spiderwebs, of course.
So you have a group of researchers led by Professor
Constantine A. Glad Say, who heads the Laboratory of Biophysics
of Excitable Systems m I p T, and they work
specifically on cardiac tissues. Isolate, a protein used in web
(24:01):
spinning called spiedroying. What they did is they seated isolated
neonatal rat cardiac cells on fiber matrices and during the experiment,
the researchers monitored the growth of the cells and they
tested their contractability right in their ability to conduct electrical impulses,
and these are the main features of normal cardiac tissue.
(24:23):
They wanted to see if that could be mimicked in
in the protein. And the monitoring, which was carried out
with the help of a microscope and fluorescent markers, showed
that within three to five days a layer of cells
formed on the substrate that we're able to contract synchronously
and conduct electrical impulses, just like the tissue of a
(24:46):
living heartwood. And this is pretty big news, right. It
doesn't mean that we're around the corner from grow your
replacement heart clinics um, but it does mean that it's
it's a serious step toward me a beating heart out
of a few cells, Like that's going to become an
eventual reality. And now you found the material. That's just
(25:08):
one more in the link to it. It's sounding more
and more like the bodies of the future will just
be riddled with spider self and I have another example
of it here. Uh. I mean, this one really kind
of blew me away because the example, if we looked
at so far that they're they're based in structure, right,
We're looking at the structure of the webbing and how
it can be used to make attachments, to to create
(25:29):
a structure, to grow tissue over, etcetera. But there were
a couple of studies that came out in a two
thousand twelve edition of Researchers at Frontiers and Optics, a
scientific journal. UH looked at two independent teams, one at
TUF University in Boston at one at c n R.
S Institute of Physics in France. UH, and they were
looking at ways that this natural spider silk could be
(25:52):
used as an eco friendly alternative two traditional methods of
manipulating light. So we're talking about, um, an alternative to
glass or plastic fiber optics and lenses. UM. Why would
you want this again? It comes back to biomedical technology, right,
the placement of sensors and tags or any kind of
(26:15):
utilized utilization of light within the human body. UM. I
mean the revelation for me here that I just did
not realize was that as it turns out, in addition
to being super sturdy and flexible, silk is a gifted
light manipulator, and so so light could travel through silk
almost as easily as it flows through through glass fibers.
(26:37):
So the potential here hits two key areas. One implanable
biodegradable optics utilized in sensors and tags that are placed
inside the body. We've talked about the the importance of
real time monitoring um of of our of our body
and how that is that can play into better management
of our overall health. And another area is that you
(26:59):
can take this on biosensors. You can take a pristine
fiber of spider silk and carry light into the body
through a very small opening um which would be quite
useful for internal imaging or even chemical diagnosis using spectroscopy,
which is the analysis of matter based on its interaction
with light. So yeah, just it's amazing to think of this,
(27:22):
like this tiny little thread of of of spider silk
going in through a tiny hole in the body and
aiding in the in diagnosis. That really, to me is like,
I think, a game changer and amazing to me that
the material is being used that way. Yeah, it just again,
it just it just drives home just how impressive this
(27:42):
material is. Yeah, and again, just to underscore that uh
impressive durability and strength, let's go back to the spider's
drag line again. It is the stuff of engineer's streams,
the tensile strength of a high grade alloy steel, while
being a sixth as dense and incredibly flexible. You can
(28:03):
draw it out about five times at some length without
compromising it. So how do you get a spider to
do better? How do you ask it to just up
its game of kevlar strength? Okay, we're still trying to
actually steal its secrets, but then we're also saying what
can we do to bump it up? Yeah, we're saying, hey,
we know you've perfected this over four hundred million years
(28:25):
of evolution, but do you think right now you could
do something to increase the durability. Well, of course we're
talking about here is some researchers. In this case, we're
talking about Nicola Puno at the University of Trento in
Italy and his team who took some seller spiders who
are also known as fulsit I and the site spider
(28:48):
Hugger dot com by the way, describes these spiders as
quote looking like something made out of many marshmallows of
pipe cleaners. So the research took these seller spiders and
they douse the spiders with either water containing carbon nanotubes
or graphine flakes. Now two materials that are both really
really strong, right, So this is an attempt to sort
(29:10):
of to supersize the strength of the of the spider
and sort of make it into it's a little spider superhero.
They checked out the spider's handiwork after they did this
for each strand of silk, and they fixed the fiber
between two C shaped cardboard holders and placed it in
a device that can measure the load on a fiber
(29:31):
with a resolution of fifteen nanomutants in any fiber displacement
with a resolution of a point one nanometers. Okay, So,
in other words, are very serious about the tin sile
strength here, and Pina wrote that the thread is the
highest toughness modulus for a fiber, surpassing synthetic polymeric high
performance fibers like Kevlar forty nine and even the current
(29:53):
toughest knotted fibers. So it was amazing about that is
not only it was the thread tougher than before, right,
tougher than kevlar, tougher than its own natural tensile strength.
But they could find the actual carbon nanitubes in it.
They just weren't sure of how it was happening. At first.
(30:16):
They thought, well, maybe they were taking it and spreading
it onto the spider silk after it came out of them,
but that was discounted. They're just not sure how it
was incorporated into their bodies to create it. So again
we find out a little more about the mystery of
spider silk, and we just end up with more questions.
It is the great mystery. Well you know, um, we
(30:38):
have one more study to to mention here, and and
this one we feel really really drives home the elegance
of the design that we see here again not only
in the structure that they build, but the but the
material that they build in the varying take some material
they build to construct it. The comparison here spy eighter
(31:00):
silk and music spidered web and U and you know,
a classically arranged piece of music. Um. In particularly, we're
looking at a study from two thousand eleven researches at M. I. T.
They created a scientifically rigorous analogy that shows the similarities
between the physical structure structure of spider silk and the
(31:22):
sonic structure of a melody. Um and taking it down,
just stripping it down to the building blocks of either
an amino acid in the case of the webbing, and
a sound wave in the case of the music. Yeah.
And it's got many different layers of sound in music
to it in this analogy, and the study explains that
(31:43):
structural patterns are directly related to the functional properties. That's
one layer of lightweight strength in the spider silk and
in the riff sonic tension that creates an emotional response
in the listener. It's interesting to think of actually melody
music is spider webs, right, and the tension that's held
within them and the structures, the repeating patterns. Yeah, it
(32:05):
just again it drives home just the elegance of the
design and just how how nuanced it is. Um. I
don't know if I'm going to start thinking of music
I like as a spider web exactly, but but but
it's it's it's a wonderful analogy that they make and
back up with data. Yeah, it's another way to look
(32:28):
at um, not Fibonacci, but symmetry and nature and the
patterns held within and only that uh, the communication, right,
because if you think about the spider web and the
vibrations that it's giving off, that perhaps is a kind
of melody to the spider itself telling it something about
(32:48):
the pacing, something about the beat of the thing that's
making it vibrate. Yeah, the sweet sweet music of of
of a creature in agony wrapped up in your web
that you could take. I'll go and uh and wrap
up some more and drain the life force from that exactly.
That's the song of the spider right there, all right.
(33:10):
So there you have it, uh, spider silk. I hope
that uh, I hope that that that you guys and
guys listening have more respect now for the spider and
what it's doing. It's not just a silly string coming
out of a spiders but it's uh, and it's not
you know, spiderweb itself is not on par with just
you know, doing some cat's cradle stuff with some string
(33:30):
and your fingers. That it's an engineering marvel at every level.
If you would like to learn more about this topic
and others, that'll be sure to head on over stuff
to Blow your Mind dot com. There's where you'll find
uh podcast videos, blog post links out of social media accounts,
and we'll make sure that we have stuff on the
landing page linking out to some wonderful resources, including the
(33:50):
how spiders Work article on how stuff works dot com,
which gives you a wonderful overview of spider anatomy. If
you have thoughts about the culture or residents of silkworms
in China, or if you have thoughts about spider webs
and silk used in biomedicine, particularly in your own body,
or even what we're talking about with melodies and the
(34:13):
patterns of spider webs, please do share those thoughts with us.
We'd love to hear from you, and you can email
us at blow the Mind House to works dot com
for more on this and thousands of other topics. Is
it how staff works dot com
Stuff To Blow Your Mind News
Hosts And Creators
Robert Lamb
Joe McCormick
Popular Podcasts
40s and Free Agents: NFL Draft Season
Daniel Jeremiah of Move the Sticks and Gregg Rosenthal of NFL Daily join forces to break down every team's needs this offseason.
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com
Las Culturistas with Matt Rogers and Bowen Yang
Ding dong! Join your culture consultants, Matt Rogers and Bowen Yang, on an unforgettable journey into the beating heart of CULTURE. Alongside sizzling special guests, they GET INTO the hottest pop-culture moments of the day and the formative cultural experiences that turned them into Culturistas. Produced by the Big Money Players Network and iHeartRadio.