What sticky sea creatures can teach us about making glue Jonathan Wilker
Translator: Hiroko Kawano
Reviewer: Tanya Cushman
So I’d like you to join me
on a field trip,
and I want to go to the beach
and take you all to the beach
and so enjoy the sea air
and the salt spray.
And let’s go down to the water’s edge,
and you’ll notice we’re getting
knocked around by the waves,
and it’s really difficult
to stay in place, right?
But now, look down,
and what you’re going to see
is that the rocks are covered
by all sorts of sea creatures
that are just staying
there in place, no problem.
It turns out that if you want to survive
in this really demanding environment,
your very existence is dependent
upon your ability to make glue, actually.
So let me introduce you
to some of the heroes of our story,
just a few of them.
So these are mussels,
and you’ll notice
they’re covering the rocks,
and what they’ve done
is made adhesives,
and they’re sticking down on the rocks,
and they’re sticking
to each other, actually.
So they’re hunkered down
together as a group.
This is a close-up photograph
of an oyster reef,
and oysters, they’re amazing.
What they do is they cement to each other,
and they build these huge,
extensive reef systems.
They can be kilometers long,
they can be meters deep,
and arguably, they are
the most dominant influence
on how healthy any coastal
marine ecosystem is going to be
because what they do
is they’re filtering the water constantly,
they’re holding sand and dirt in place.
Actually, other species
live inside of these reefs.
And then, if you think about
what happens when a storm comes in,
if the storm surge first has to hit
miles of these reefs,
the coast behind it
is going to be protected.
So they’re really quite influential.
If you’ve been to any rocky beach
pretty much anywhere in the world,
you’re probably familiar
with what barnacles look like.
And so what these animals do -
and there’s many others,
these are just three of them -
is they make adhesives,
they stick to each other and to the rocks
and they build communities,
and by doing this, there’s a lot
of survival advantages they get.
So one of them is that just any individual
is subjected to less of the turbulence
and all the damaging features
that can happen from that environment.
So they’re all hunkered down there.
Then, also, there’s a safety
in numbers thing
because it also helps you
keep away the predators,
because if, say, a seagull
wants to pick you up and eat you,
it’s more difficult for the seagull
if they’re stuck together.
And then another thing is it also helps
with reproductive efficiency.
So you can imagine that
when Mr. and Mrs. Barnacle decide,
“OK, it’s time to have
little baby barnacles” -
I won’t tell you
how they do that just yet -
but when they decide it’s time to do that,
it’s a lot easier,
and their reproductive efficiency’s higher
if they’re all living close together.
So we want to understand
how they do this:
How do they stick?
And I can’t really tell you
all the details,
because we’re still trying
to figure it out,
but let me give you a little flavor
of some of the things
that we’re trying to do.
This is a picture of one of the aquarium
systems we have in our lab,
and everything in the image
is part of the system,
and so what we do is we keep -
and you can see in the glass tank there,
at the bottom, a bunch of mussels.
We have the water chilled,
we have the lights cycled,
we actually have turbulence in the system
because the animals make
more adhesives for us
when the water is turbulent.
So we induce them to make the adhesive,
we collect it, we study it.
They’re here in Indiana;
as far as they know,
they’re in Maine in February,
and they seem to be pretty happy,
as far as we can tell.
And then we also work with oysters,
and up top, it’s a photo
of a small reef in South Carolina,
and what we’re most interested in
is how they attach to each other,
how they connect.
So what you can see in the bottom image
is two oysters cementing to each other.
We want to know what’s in between,
and so a lot of times,
we’ll cut them and look down,
and in the next series
of images we have here,
you can see, on the bottom,
we’ll have two shells,
the shell of one animal
and the shell of another animal,
and the cement’s in between.
If you look at the image on the right,
what you can maybe see
is that there’s structure
in the shell of each animal,
but then, the cement
actually looks different.
And so we’re using all sorts
of fancy biology and chemistry tools
to understand what’s going on in there,
and what we’re finding
is the structures are different
and the chemistry is actually different,
and it’s quite interesting.
And in this picture -
I guess, let me step back
before I tell you what this is.
So do you know the cartoon
“The Magic School Bus”?
Or if you’re a little bit older,
“Fantastic Voyage,” right?
And you remember, they had characters
that they would shrink down
to these microscopic levels,
and then they would sort of swirl in
and swim around and fly around
all these biological structures?
I think of this as like that,
except for it’s real in this case.
And so what we did is we have
two oysters that are stuck together,
and this area used to be
completely filled in with the cement,
and what we’re finding is that the cement
has lots of different components in there,
but broadly speaking,
there are hard, non-sticky parts
and there are soft, sticky parts,
and what we did is we removed
the non-sticky parts selectively
to see what’s left -
for what’s actually
attaching the animals -
and what we got is this,
and we can see there’s a sticky adhesive
that’s holding them together.
And I just think it’s a really cool image
because you can imagine yourself
flying in and going back there.
Anyways, those are some of the things
we’re doing to understand
how marine biology
is making these materials.
And from a fundamental perspective,
it’s really exciting to learn.
But what do we want
to do with this information?
Well, there’s a lot
of technological applications
if we can harness
what the animals are doing.
So let me give you one example.
So imagine you’re at home
and you break your favorite figurine
or a mug or something like that.
You want to put it back together.
So where do you go?
You go to my favorite place in town,
which is the glue aisle
of the hardware store.
I know where you spend your nights
because you’re all hip, cool people,
because you’re here,
and you’re going to bars and concerts -
this is where I hang out every night.
So anyways,
so what I want you to do is get one
of every adhesive that’s on the shelf,
bring it home,
but before you try
to put things back together,
I want you to try to do it
in a bucket of water.
It’s won’t work, right?
We all know this.
So obviously, marine biology
has solved this,
so what we need to do is figure out ways
to be able to copy this ourselves.
And one of the issues here
is you can’t just go and get
the materials from the beach,
because if you get some mussels
and try to milk them for their adhesive,
you’ll get a little bit of material,
but you’re never going to have enough
to do anything with, just enough to see.
We need to scale this up,
ideally maybe train-car scale.
So on the top is an image
of one of the types of molecules
that the animals use to make their glue,
and what they are is very long
molecules called proteins,
and these proteins happen to have
some fairly unique parts in them
that bring about the adhesive properties.
What we want to do is take
those little parts of that chemistry,
and we want to put it into
other long molecules that we can get,
but that we can make
on a really large scale,
so you might know them
as plastics or polymers,
and so we’re sort of
simplifying what they do
but then putting that adhesion chemistry
into these large molecules.
And we’ve developed many different
adhesive systems in doing this.
When you make a new adhesive
that looks pretty good, what do you do?
You start running around the lab,
just sticking stuff together.
In this case, we took a bit of a glue
and glued together two pieces of metal.
We hung something from it
to see what it looked like,
so we used a pot of live mussels,
and we thought we were very clever.
(Laughs)
We’re obviously much more
quantitative about this most often,
and so we benchmark
against commercial adhesives,
and we actually have some materials now
that are stronger than superglue.
So to me, that’s really cool.
That’s a good day in the lab:
it’s stronger than superglue.
And here’s something else that we can do.
So this is a tank of seawater,
and then in that syringe
is one of our adhesive formulations.
What we’re doing is we’re dispensing it
completely underwater
on a piece of metal.
And then we want to make
an adhesive bond, or joint.
So we take another piece of metal,
and we put it on there
and just position it.
And you want to let it set up
for a while, give it a chance,
so we’ll just put a weight
on it, nothing fancy.
This is a tube with lead shot
in it, nothing fancy.
And then you let it sit for a while.
So this has never seen air;
it’s completely underwater.
And you pick it up.
I never know what’s going to happen;
I’m always very anxious here.
You pick it up …
and it stuck.
To me, this is really cool.
So we can actually get
very strong underwater adhesion.
Possibly, it’s the strongest or
one of the strongest underwater adhesives
that’s ever been seen.
It’s even stronger than the materials
that the animals produce,
so for us, it’s pretty exciting,
it’s pretty cool.
So what do we want to do
with these things?
Well, here are some products
that you’re probably really familiar with.
So think about your cell phone,
your laptop, plywood in most structures,
the interior of your car, shoes,
phone books - things like this.
They’re all held together with adhesives,
and there’s two main problems
with the adhesives
used in these materials.
The first one is that they’re toxic.
So the worst offender here is plywood.
Plywood or a lot of furniture
or wood laminate in floors -
a main component of the adhesives
here is formaldehyde,
and it’s maybe a compound you’ve heard of.
It’s a gas, and it’s also a carcinogen,
and so we’re constructing
a lot of structures from these adhesives,
and we’re also breathing
a lot of this carcinogen.
So not good, obviously, right?
The other issue is that
these adhesives are all permanent.
And so what do you do with your shoes
or your car or even your laptop
at the end of life,
when you’re done using it?
For the most part,
they end up in landfills.
There’s precious materials in there
we’d love to be able to get out
and recycle them,
but we can’t do it so easily,
because they’re all stuck together
permanently, right?
So here’s one approach we’re taking
to try and solve some of these problems,
and what we’ve done here
is we’ve taken another long molecule
that we can actually get from corn,
and then into that molecule,
we’ve put some of the adhesion
chemistry from the mussels.
So because we’ve got the corn
and we’ve got the mussels,
we call this our surf-and-turf polymer.
And it sticks. It sticks really well.
It’s very strong.
It’s also bio-based. That’s nice.
But maybe more importantly, here,
it’s also degradable;
we can degrade it
under very mild conditions,
just with water.
And so what we can do
is we can set things up
and we can bond them
strongly when we want,
but we can also
take them apart when we want.
It’s something we’re thinking about.
And here is a place
where a lot of us want to be.
Actually, in this specific case,
this is a place we do not want to be,
but we’d like to replace this.
So sutures, staples, screws:
this is how we put you back together
if you’ve had some surgery or an injury.
It’s just awful. It hurts.
In the case of the sutures,
look at how much you’re making
concentrated, mechanical stresses
as you pull things together;
you’re making sites for infection;
poke holes in healthy tissue -
it’s not so good.
Or if you need a plate
to hold together your bones,
look at how much healthy bone
you have to drill out
just to hold the plate in place -
so this is awful.
To me, it looks like these were devised
in a medieval torture chamber,
but it’s our modern surgical joinery.
So I’d love it if we’d get to a place
where we can replace systems like this
with adhesives, right?
It’s not easy.
We’re working on this,
but this is not easy.
So think about what you would need
for adhesives in these cases.
So first of all,
you would need an adhesive
that will set in a wet environment.
And if you look at the silly
little picture there,
it’s just to illustrate that our bodies
are about 60 percent water,
so it’s a wet environment.
It’s also to illustrate that this is why
I am a scientist and not an artist.
I did not miss my calling at all.
So then, the other requirements you need
for a good biomedical adhesive:
it needs to bond strongly, of course,
and it needs to not be toxic.
You don’t want to hurt the patients.
And getting any two of those requirements
in a material is pretty easy.
It’s been done many times.
But getting all three
hasn’t been done; it’s very hard.
And then if you talk to surgeons,
they get really picky:
“Oh, actually I want the adhesive to set
on the same time frame as the surgery.”
Oh, okay.
Or, “Oh, I want the adhesive to degrade
so the patient’s tissues
can remodel the site.”
So this is really hard.
We’re working on it.
This is just one image we have.
So we’re getting all sorts of bones
and skin and soft tissue and hard tissue,
and sometimes we’ll whack it
with a hammer.
Usually, we’re cutting it
in very precise shapes;
then we glue them back together.
We’ve got some exciting results,
some strong materials,
some things that look
like they’re not toxic.
They set wet, looks pretty good,
but I won’t tell you we’ve solved
the wet-adhesion problem,
because we haven’t,
but it’s certainly
in our sights for the future.
So that’s one place that we’d like
to see things go farther down the road.
There’s lots of other places,
too, you can imagine,
we might be better off
if we could get more adhesives in there.
So one thing is cosmetics.
So if you think about people putting
on fake nails or eyelash extensions here -
like this -
what do they use?
They use very toxic
adhesives right now.
So it’s just ripe for replacement.
That’s something we’d like to do.
And there are other places too.
So think about cars and planes.
The lighter you can make them,
the more fuel efficient
they’re going to be.
And so if we can get away
from rivets and from welding
to put more adhesives in there,
then we might be better off
with our future generation
of transportation.
So for us, this all
comes back to the beach.
So we look around and we wonder,
“How do these sea creatures stick?
And what can we do with the technology?”
And I would argue that we have
really a lot of things we can still learn
from biology and from nature.
So what I’d like to encourage
you all to do in the future
is put down your nonrecyclable
laptops and cell phones
and go out and explore the natural world
and then start asking
some of your own questions.
Thanks very much.
(Applause)