cc >> Welcome, everybody,
to Wednesday Nite at the Lab. I'm Tom Zinnen.
I work here at UW-Madison for UW-Extension.
We're delighted to have you here.
We have Wednesday Nite at the Lab every Wednesday night, 50
times a year. It's co-organized by the
Wisconsin Alumni Association and UW-Madison Lifelong Learning
Institute. So, happy to have everybody here
tonight. Tonight, I'm delighted to have
two speakers on nanotechnology. The first is Kimberly Duncan.
She's a post-doctoral associate with the Interdisciplinary
Education Group of the UW-Madison Materials Research
Science and Engineering Center, which everybody likes to call
MRSEC. The IEG focuses on creating
programming and instructional materials on nano-scale science
and engineering for a variety of audiences and settings.
Prior to coming to UW-Madison, Duncan was the Senior Science
Policy Fellow with the American Physical Society's Office
of Public Affairs in Washington, D.C.
She holds a PhD in chemistry from Princeton University.
And Katie Cadwell, who's also a post-doctoral researcher for
the Interdisciplinary Research Group of MRSEC.
She holds a PhD in chemical engineering from our fair
UW-Madison. Please join me in welcoming Kim
and Katie to Wednesday Nite at the Lab.
( applause ) >> Thanks for that introduction.
And thanks for such a great turnout tonight, especially with
the new date, doing Thursday night at the lab instead of
Wednesday, as the name of the event says.
As Tom said, tonight we are going to do a brief journey into
the nano world. And together, we'll explore what
is nanotechnology; what is it doing for us; and where we might
we find it in our everyday life. Thankfully, Tom got all the
acronyms and the long-winded names of where we work, the
Interdisciplinary Education Group of the MRSEC.
The role of our group is to do education events like this one,
to help get the public informed about nanotechnology.
And so, a lot of us may have heard already, the term
nanotechnology. And really, it's quite possibly
all around us. It's already in the movies you
see in Hollywood. Michael Crichton started a big
stir about it a few years ago, talking about self-replicating
nanobots that were consuming human flesh.
We're also seeing it in the cars that we drive and the materials
that make up the bumpers and other parts of the car.
In our computers, as the silicon chips get smaller and smaller.
We have it in our clothes, for those of us who are a little bit
more messy, like myself. I've got pants that I can spill
anything on and it washes right off thanks to nanotechnology.
And even one of my favorites is the self-cleaning windows.
I know how much it really stinks to get out there in the spring
and clean them off. So hopefully, nanotechnology
will prevent us from ever having to do that again.
So it is all around us. We're already seeing things
about it in the media. But what exactly is
nanotechnology? If you're out there and you
don't know, don't worry. Actually, recent studies show
only about 50% of Americans have heard of the word
nanotechnology. And a very small percentage
of those people can actually technically and correctly
define it. So I'm just going to put up some
formal definitions. One comes from the federal
government. It sounds very professional.
"Nanotechnology is the understanding and control of
matter at dimensions of roughly 1 to 100 nanometers,
where unique phenomena enable novel applications."
And it says that it's very interdisciplinary.
If you look at the MRSEC, you'll notice that the professors that
do nanotechnology research span anywhere from chemical
engineering, physics, materials research, biology.
It really is very interdisciplinary as a science.
But for the public, what most of us want to walk away with is
that the nanometer is extremely small.
And at the nanometer scale, materials behave differently.
And we're trying to harness these new behaviors as a way
to come up with new and novel applications.
So exactly how small is a nanometer?
We'll just to start off to talk about the metric system.
Some of us may remember that from back in school.
You're likely more familiar with the English system with the yard
and the foot. But when thinking about the
metric system, the base unit is the meter.
I can then add prefixes to that system to say whether or not
it's bigger than a meter or smaller than a meter.
And the nanometer is one-billionth of a meter.
So if I took a meter stick, it's about the same length as a yard,
and I cut it up to a billion pieces, each one of those pieces
would be a billionth of a meter in length.
Probably, I know for me, that doesn't mean a whole lot.
It's hard to imagine exactly how big or how many is a billion.
So let's try to put this in our own cultural perspective.
So if I talk about a kilometer. I've got a picture of the Sears
Tower down in Chicago. It's the tallest building in the
United States. It stretches 1750 feet into the
air. It's only half a kilometer high.
So a kilometer, pretty long. It's 1,000 meters.
It's also the distance, if you're standing at the edge of
the UW campus and looking down State Street, it's approximately
a kilometer to the State Capitol.
So many of you may have already walked that at one point this
week, and you'll remember, oh, okay, that's about a kilometer.
If I cut the kilometer into a thousand pieces,
I get down to the meter. A meter is approximately the
height of a bicycle seat for a typical adult bicycle.
If I cut that meter into a thousand more pieces, then I'm
down to the millimeter scale. It's about the same size
as the tip of a pen. So, it's pretty tiny already.
If I keep going down-- And remember, these are all
things that we can still pretty easily see.
If not with our naked eye, with eye glasses or
a magnifying glass to see the tip of that pen.
If I go even smaller, I get down into the micro scale.
So I take that millimeter and cut it, again into a thousand
pieces. I'm left with a micron.
A human hair, which sort of pushes our eyes to the farthest
they can go, to be able to see the diameter of a hair if you
held it on end and looked down the small end of it.
That's 40 microns. So, similar on a same scale of
the micron is a red blood cell. It's about 7 microns.
These are still things we can see with a typical light
microscope that you might use in a biology class, or that you can
buy at a specialty sort of scientific toy store.
A nanometer is a thousand times smaller than this.
So when we get down to the nano scale, one nanometer, we're on
the scale of atoms. So the atoms, the ubiquitous
things that make up everything around us.
If you've gotten a virus, it's about 3 to 50 nanometers,
depending on the virus you look at.
DNA, the building block of life, the diameter of those helices
are about 2.5 nanometers wide. And this iconic picture over
here on the right, if you have heard of nanotechnology, you
might be familiar with that picture.
It's a picture of 49 iron atoms that have been painstakingly
placed, atom by atom, on a surface.
The diameter of this corral is 14 nanometers.
So, nanometer, the take away definition, very, very, very
small. So small, you can't see it
with your eyes. And so at this point, I'm going
to pass it off to my colleague Katie.
So Kim mentioned that when you're looking at red blood
cells, which are on the micron to 10 micron level, we can still
see those using light. And we can't see things like
viruses, DNA and molecule that are down on the nano scale.
And does anyone know why we might not be able to see those
things using light? Any volunteers?
( inaudible ) Optical length.
Sort of. If you could, say, grind a lens
fine enough that you could get all the way down to focusing on
it. And the reason you can't see
things that are down on the nano scale is because they're
actually smaller than the wavelength of light.
So light is too big of a tool to use to see things on the nano
scale. So if we can't see things on a
nano scale, how is it that we're able to "see" them?
So everyone should have, maybe it was in their seat when they
sat down, or on a table in front of them, one of these magnets.
And we're going to do a little experiment to kind of
demonstrate how it is that we can see things that we can't
actually see using light. So each one of these magnets
has a probe strip on the end. And if you--
( inaudible ) Okay.
They're also in the back if you want one.
So you can bend the probe strip and break it off from the rest
of the magnet. And then what I'd like for
everyone to do is to take this probe strip, and along the black
side of the magnet, where there's no sticker, draw the end
of their probe stick lengthwise across the magnet and then
widthwise across the magnet. Does someone want to tell me
what they observed when they pulled the strip the long way
across the magnet? ( inaudible )
It feels smooth. And then what happens when you
pull the strip across the short end of the magnet?
It kind of bumps up and down, right?
So the reason it does this is because this magnet has been
manufactured to have a pattern of north and south poles in it.
Now, when you look at the back of the magnet, can you see where
the north and south poles are? No, you can't see them.
But I'm going to have you guys vote now on what the pattern of
north and south poles would look like on this magnet, if you
could see them. So, is it all north or south
pole? Is it stripes of north and south
poles? Or is it a checkerboard?
How many people want to vote for all one pole?
All right. How about stripes of north and
south poles? And how about a checkerboard?
So most people think that it's stripes of north and south
poles. And the reason you think that is
because when you dragged the strip this way, it felt smooth.
There was no change in whether your probe was "seeing" a north
and south pole. And when you dragged your strip
this way, it bumped up and down because it was alternately
repelled and attracted to the north and south poles.
So even though you couldn't see with your eyes, what the
magnetic pattern was on this magnet, you still knew by using
this probe. And scientists and engineers
use a similar technology. In general, they're called
scanning probe microscopies. And I've shown one here,
specifically, an atomic force microscope.
And what this does is it has a very, very, very fine tip.
And this tip is attached to the end of a cantilever that's
really delicate. And this tip is maybe a few
molecules wide at the end. So it's very, very small.
And you can drag it across a sample, and just go back and
forth in both directions. And as this tip goes across the
surface and encounters features on the surface, it moves up and
down. As it does that, you can shine a
laser on top of this cantilever. And very, very small
fluctuations in how that cantilever moves can be
projected into much larger movements that can be detected
with a laser detector. So, if Kim has a shaky hand
today, because maybe she's a little nervous, even though
she's not moving her hand very much at all, you can definitely
see the movement further away in the laser.
It's amplified by the distance. And by doing this, you can
actually map out surface features down to a very, very
small scale. So what I'm showing you here is
an AFM image from Professor Max Lagally, here at UW-Madison, of
a silicon wafer. And I have a silicon wafer here
with me, in a petri dish. And I'll pass it around.
When you look at the silicon wafer, it looks very smooth and
shiny. It has a mirror-like surface.
And so, you can't see with your eye that there's any features
there at all. But when you use the atomic
force microscope, we can actually have a resolution
that's below a nanometer. And these features that you see
are actually just one single atom in width.
And so, using these scanning probe microscopies, we can see
what we can't really see. And I'll pass it back to Kim.
Mm-hmm? ( inaudible )
...the surface, so that you know that your disturbances
are caused by molecules, not by, you know, the physical
whatever you polished it with. Or the kind of the more things
we think of as a physical surface.
I think that would have-- I can't imagine something that
would be smooth enough so that, you know, that something
detecting the surface would be seeing molecules, not artifacts
of polishing. >> So partly, we know that those
are atoms or atom vacancies because of the size that they
are. Also, silicon itself, the way
that it will cleave. It actually makes, you can make
very abrupt and clean cuts in silicon.
And you still polish it, but it actually likes to kind of
splinter along the crystalline faces.
And so, it's well-known that you're going to have a very
nice, clean and flat surface, at least until you get down to the
atomic scale. But even on the atomic scale,
this is really flat. >> It's not a completely uniform
pattern. So are they reflections of
light? >> You're not seeing reflections
of light. Because light is, you know, a
thousand time larger than these features.
What are the stripes? There are several different
ones. >> These stripes versus the
stripes here? >> Right, it looks like a very
regular background, and then there's some black spots and
some white. >> This is an artificially
colored image, is the first thing that you have to realize.
It's not white, black and turquoise, like it looks up here
on the screen. That was how someone decided to
map it out using a computer program.
There's no color at all, in fact.
What they've done is they've used different colors to
represent different heights. So, usually the way they do it,
I don't know specifically with this image, is they'll have
lighter colors representing higher places.
So there's just a few more atoms in this spot that's causing that
tip to deflect further from the surface.
So the coloring is completely artificial.
We've had a brief introduction to what the nano
scale is and how we see there. But what is the big deal?
Well, a lot of people are saying that nanotechnology is the next
revolution, that nanotechnology will do the same thing for us
that the industrial revolution did in the early 1900s.
It will do the same thing for us that the Internet did for us in
the '80s and '90s. So if we think about life in the
1900s versus life today, very different.
The same thing, I imagine. Many of us can't think of going
a day without checking our email or looking online for the news.
I apologize, I'll scooch out of the way.
The news of the day or even doing a little Internet
shopping. And you'll see that a lot of
these revolutions for technology take about 100 years.
Railroads came around. There was kind of a quick growth
period where a lot of development happened.
A steady climb, and then a plateau as railroads became more
commonplace. We weren't building as many
tracks and such. Well, for nanotech-- Or the same
thing goes for the computer taking off.
We're starting to probably plateau for computers.
But for nanotech, we're pretty early on in this take-off of
this next revolution, for nano to be the next big thing.
A lot of the proponents of nanotechnology think we're going
to follow this curve as it's written.
Some of the naysayers say we're going to get to about here, and
then just turn over, and nanotechnology is going to prove
to be all hype. So it's up to you guys out there
to start thinking, is it hype or is it really a technological
promise. So there are a lot of people
saying it's going to be a big deal.
Just one quote I wanted to point out.
One of the reasons that people think it's going to be a big
deal is that it has an amazing possibility for impact on
products that are traded on the global market.
Mike Roco, who is the director of a government initiative
called the National Nanotechnology Initiative,
a group that's sort of involved in setting the U.S.'s trajectory
for research and development in the field of nanotechnology.
He thinks that by 2015, nanotechnology enhanced products
will account for $1 trillion, and that in order to reach this,
we're going to need two million workers to fill the positions in
nanotechnology. So a really huge opportunity for
companies, consumer products and other things.
And also a huge opportunity for job creation.
Supporting Dr. Roco's claim is that the federal government has
already started heavily investing in this branch of
science. You'll see there 13 agencies on
the left hand side. Being from D.C.,
I'm really used to the alphabet soup of the way that
the agencies are represented. However, you'll notice at
the top, we're talking about the National Science Foundation,
the Department of Defense, the Department of Energy.
They're sort of the big players when it comes to scientific
research. You can see that their
investment is much heavier than places maybe like the Department
of Justice, or even the Department of Transportation.
But the total investment for 2008 is projected to be
$1.4 billion. So there are people out there,
and certainly a lot of scientists who believe that this
is going to be a great place to be investing our money.
Why do people think it's such a big idea?
It turns out when things get very, very small, that size does
actually matter. At the top of this slide you'll
see some gold and silver bars. Most of us are probably familiar
with gold or silver, either through jewelry we own or metal
work we've seen. We might not have those gold
bars sitting in our closets at home.
Maybe just take a look if you have ring or earrings on to
remind ourselves that gold is shiny.
It's yellow in color. Silver is shiny.
It's gray in color. However, when you get down to
the nano scale, when you go from bulk all the way down to the
nanometer, the silver and gold actually change color.
I have a picture up here. The nano particles of silver
turn yellow. Whereas nano particles of gold
turn red. I brought a sample of gold and
silver nano particles here that I'll pass around.
Please do not open them. Don't try.
I've super glued them shut, but don't try to beat
the super glue. >> If they're smaller than the
wavelength, how can there be color?
That is a great question. And what happens is that the
light interacts with the particle in a very different
way. So the particle is made up atoms
that have electrons that are freely roaming on that particle.
And then when the light wave comes in, it causes those
electrons to vibrate. Then they're able to emit a
color. So it is smaller than the
wavelength of light. It's the way that the electrons
interact with the light. So you might look at these vials
and think I just put Kool-Aid in there.
There's no particles. But I'm not that sneaky.
In addition to the vials I'll pass around, I'll pass around a
laser pointer. Please make sure not to shine it
in your neighbor's face as you are investigating it.
If you take the laser pointer, and you shine it through, I'm
going to try not to hit Katie in the eye, shine it through the
nanoparticle vial, you'll actually be able to see the
laser pointer pass through. The reason you're able to see it
is because they're are little itty bitty particles that are
interacting with this laser. That's why you see the laser
pointer appear. To test yourself, I have a vial
of plain water. You can do the same thing.
You can't see the laser pointer go through the water because
there's no physical particles. There's molecules, but there's
no particles for the light to interact with.
You can do it for both the gold and the silver.
( inaudible ) The particles are approximately,
for the silver, are approximately
50-100 nanometers large. So if you think that an atom
is a tenth of a nanometer, there's a considerable number
of atoms. The gold is about
25 nanometers in size. It turns out, though,
nanotechnology is not really that new.
Medieval artisans have been using this technique of creating
gold and silver nanoparticles, and seeing their color change
for a thousand years. They didn't know it at the time.
But when the artisans back in the Middle Ages added the metal
oxides and the metal chlorides to their hot, molten glass, the
process actually caused gold and silver nanoparticles to form.
So the way that they got all these different colors was by
adding different metals and creating nanoparticles of the
metal within the glass. They certainly didn't know
that's what they were doing. What they saw was when they
added these compounds to the glass, it made this beautiful
color. And they put it to good use.
Did I hear a question? ( inaudible )
They're solid particles. And they're embedded
in the glass. They're embedded.
Are there no particles in water?
There are molecules in water. But the nanoparticles are a
collection of atoms. Do you have a better way to
explain that? >> When you're talking about
particles, we're actually talking about a big chunk of
atoms and molecules that are all stuck together.
So, as Kim mentioned, your average atom, say, is just going
to be on the order of a tenth of a nanometer.
And we're talking about particles that are 50 nanometers
across. So that's a whole lot of
molecules or atoms. >> Yeah?
What about colloids? Wouldn't you call a colloid like
nanoparticles? >> They are called colloidal
suspension of nanoparticles. So it does fall under the
definition of a colloid. So besides using this
nanoparticles of gold back in the Middle Ages, we're also
using it today for a very dramatically different
application. It turns out that there are
researchers at Rice University who are developing ways to treat
cancer using nanotechnology. They create something called a
gold nanoshell. So they take a piece of glass
and they coat the outside of that glass with a very thin
layer of gold or, I believe they have also tried silver.
And as they change the size or thickness of this gold
nanoshell, they get a lot of different colors.
A lot like the picture I just showed on the last slide, where
we had all those different colors in the same glass.
Why does this work? Well, it turns out that these
nanoparticles or these nanoshells of gold absorb
infrared light. And when they absorb the
infrared light, the atoms get very excited because they're
being irradiated with light. And they get hot.
And then the scientists have figured out a way that these
nanoshells can be injected into the body, localized into a
cancer tumor. And then when the tumor is
exposed to infrared light, the nanoshells heat up.
They increase in temperature over 30 degrees from where they
were, and it causes the cells to die.
The great thing is also it's very targeted and the infrared
light doesn't affect normal, healthy tissue.
We're exposed to infrared light during a regular day and we're
not affected. However, if we had gold
nanoshells within a tumor, it would cause the tumor to heat
up, the cells to die. And hopefully they're working
towards a way of treating cancer in the future.
They're just starting clinical trials.
So this won't be a therapy that will be available any time soon.
But it's certainly a way that these nanoshells are being
utilized for a treatment. Just another example of why
size matters. Something we might be more
familiar with in our daily life is sunscreens.
I know that with my fair skin, I'm constantly slathering white,
creamy, goopy stuff all over me. And there's always a spot that I
have on my face. It's embarrassing to walk around
the beach with a big, white, blotchy spot on you.
However, the way that the sunscreens work is that there's
zinc oxide and titanium dioxide in there.
And it's those particles of the zinc oxide and the titanium
dioxide that reflect the light and prevent us from getting a
sunburn. That's where the white color
comes from. If I start to more finely divide
those particles until they're the size on the nano scale,
again, they interact with the light differently and now the
sunscreens are clear. So you can easily buy these
sunscreens on the market now. You might have already purchased
them this past summer or gearing up for the summer that's coming.
Besides color, lots of other things change with the nano
scale. I just wanted to point out that
there's also reactivity, how reactive something is with its
environment. For soda cans, if it's sitting
on my desk, I have no worry that it's going to explode or hurt me
in any way. But if I take the same aluminum
that's in a soda can, and I make it down to the nano scale, it
actually turns out to spontaneously combust.
All right, so now we're going to take a little break from just
the plain old lecture and do a demonstration.
I would like two volunteers from the audience.
All right, I have one. I need a second, two, all right!
So what I have up here is just two plastic tubes.
And in the bottom of each tube is a metal cylinder.
I have some stainless steel balls.
It doesn't matter which one you take.
I promise you they are the same. Now, here's what I need you guys
to do. I'm going to count to three.
I'm going to say, "One, two, three, go."
And on "go," I want each of you to drop your ball into one
of these cylinders. All right.
One, two, three, go. You're really good at this.
Have you been practicing? ( light laughter )
That's amazing. You got that ball to bounce
for a long time. Let's grab these
and try it again. Maybe it was just your superior
technique. So maybe we should start over.
Let's do it one more time. I'll count to three.
One, two, three, go. Okay, so maybe it wasn't your
ball bouncing skills that led that one to bounce longer.
So what did you guys notice happened between the two trials?
Anyone? I switched the two cylinders,
right? So it's not the balls that are
different. It's not my two lovely
assistants. I'm done.
Thank you very much. What's actually different are
the two metal cylinders. And I'll go ahead and pass these
around. You'll probably notice that
they're a little bit different. First of all, this one has
something glued to the top. And the reason this one has
something glued to the top instead of just being made out
of one single metal, is the stuff that's glued to the top is
really expensive. I wasn't going to make a big
cylinder out of it. But what's actually important is
the tops of the cylinders, anyway, because that's what the
stainless steel balls are bouncing against.
So as I pass these around, I kind of want you to look at the
surface. And remember that the one that
has the extra stuff on top is the one that the ball bounced on
for a really long time. And as I pass these around,
you'll notice that on that one, the one that the ball bounced a
long time on, it's really smooth and shiny.
It's gotten a little bit scratched up from sitting around
in a container with a bunch of other metal cylinders.
But overall, it's smooth. Then if you look at the one
where the ball didn't bounce as much, it has a lot of pits in
it, dents. And where are those dents coming
from? From dropping stainless steel
balls on it. So that one dents.
But the one the ball bounces on a long time doesn't dent.
So what's the difference between these two cylinders?
Well, the one that's all dented, it's just made out of stainless
steel, also. But the one that is not dented,
the one that the ball bounced a long time on, is made of
something called amorphous metal.
So it turns out that not only does size matter in the property
of a material, but the arrangement of molecules down on
the nano scale also make a difference in the properties
that a material exhibits. So in regular metals, regular
metal, such as stainless steel, the atoms within that metal tend
to form a very regular arrangement.
What we call a crystalline lattice.
And because these atoms are all arranged nicely, they can kind
of move as a group and slide past one another along fault
lines. And that's what's happening to
the stainless steel cylinder when it's being hit the
stainless steel ball. That stainless steel ball is
taking some of its kinetic energy, transferring it to the
atoms within the stainless steel cylinder, and actually causing
those atoms to shift along those fault lines.
So you get a dent. The ball loses some of its
energy to the cylinder. And eventually, it quits
bouncing. However, with the amorphous
metal, this particular amorphous metal is a mixture of five
different atoms. And I'll tell you just off the
top of my head, I don't remember what all five of them are right
now. And these metals are all mixed
together at a very high temperature and then cooled
really, really, really fast. This metal is cooled so fast
that the atoms don't have time to arrange themselves into a
nice, regular crystalline lattice.
Instead they get stuck with no particular form or pattern.
That's why we call it an amorphous metal.
Amorphous means no shape, no form.
Because these atoms are just all jumbled together and stuck,
when the stainless steel ball hits this surface, it's not able
to easily dislodge a whole bunch of atoms, because there aren't
any clear fault lines in that atomic structure.
So, the stainless steel ball doesn't lose kinetic energy to
creating dents in the surface, and it bounces for much, much
longer. Eventually, it's going to stop.
Some energy is lost to acoustics.
You heard it as it was bouncing on the surface.
That's acoustical energy. Some of the energy is lost just
between molecules in the air. But it did bounce a lot longer.
And so some of the applications for amorphous metal, it's
already being used in sports equipment.
So you can't use it in a regulation game, but you can get
golf clubs that have amorphous metal, I guess, I'm actually not
a golfer. But it's on the end of the club
where you hit the ball. And because you're not losing
energy to deformation within the head of your golf club, you're
actually able to, in theory, hit the ball further using one of
these golf clubs. If you have a lousy aim, it's
not going to help you out any. On a more practical, and less
just recreational side, these have been proposed for use in
surgical metals. If you want to cut through
someone's bone, cartilage or other tissues, you don't want a
knife that's going to dull quickly.
And so, they can use amorphous materials for these knives and
they stay sharp for a lot longer.
And Kim's up again. >> So we talked about what seems
like some high-tech applications for nanotechnology.
Cancer treatment. I don't know how many stained
glass artists we have out there. But nanotechnology is actually
in your life already. I mentioned a few in the
beginning. I mentioned the books, the
movies, and some products. We're just going to talk about a
few more products that might actually already have turned up
in your house. It turns out that silver
nanoparticles have an anti-microbial property.
So they kill the bacteria that might be building up.
So manufacturers are now starting to impregnate materials
with these silver nanoparticles so that the material, possibly
on the right hand side, like a Tupperware, can kill the
bacteria that is starting to form in your Tupperware.
Maybe it makes the Tupperware last longer because you don't
have things go bad in it. You don't have to throw it away.
It's also been showing up in athletic apparel, so you can
maybe wear your workout shirt once or twice before you have to
wash it and it starts to smell. The same thing goes for socks.
Your refrigerator. I mentioned Tupperware.
There's even a washing machine that was developed that had
these silver nanoparticles in the basin, that touted
an anti-microbial effect. >> How does it have an
anti-microbial effect? >> They're pretty secretive
about how it works. But what I understand as far as
how the silver interacts, is that silver has been used as an
anti-microbial before. Sometimes, in previous years and
sort of in older days, they would put silver solutions into
cuts to kill things. And so the silver causes the
cells to die. What they found out with the
nanoparticles is the way to get them into materials like socks,
and fibers, and other things. >> They used to use silver
nitrates. >> That's a great example.
( inaudible ) >> Unfortunately, what
they may do is select for micro organisms that are
resistant to the materials, and then become problematic
in other ways. >> That's a great point
to realize. There's a lot of these products
on the market. And we have to think about how
they should be regulated. What happens to the
nanoparticles that are in that washing machine when you use it?
What happens as you wash the socks?
The nanoparticles can come off in the wash and get into your
water stream. These are all really big
questions that scientists and policy makers across the board
are trying to figure out how best to address these issues.
It seems like it would take an awful lot of them to clog up
any system. >> That's one of the issues.
In a washing machine, it would take millions and millions
and millions. >> There are a couple questions.
What do we know about nanoparticles being absorbed
into our body? >> It's a relatively new field
of study. It is starting to get a lot more
attention. They have some studies that
point to certain sizes of nanoparticles being cancer
causing, causing other issues within cells.
There's been studies that have shown that carbon nanotubes and
other types of nanotechnology, or another form of carbon, can
actually cross the blood-brain barrier.
So these are all really big questions that people are
starting to investigate. And they're doing toxicology
studies, of how much nano until a cell dies.
Or, how much, at what size are they dangerous.
Sometimes the size of one gold particle, it's not toxic.
But when you get to another size, it is toxic.
So there's a lot of questions that remain unanswered about
nanotechnology. >> Do these particles exist in
nature? Are we really exposed to them?
In some cases, yes. The carbon nanotubes I just
mentioned are actually a natural product of combustion.
The same thing goes for another carbon molecule called a Bucky
Ball. Again, a natural product of
combustion. Some of them do occur naturally.
Things like for welding, there are things called plumes
that come off a weld. Those particles are actually
nano-sized, pieces of metal. Another thing on these products,
there's many products that say "nano" and it really doesn't
have any. >> Exactly.
A great example of that is the iPod Nano.
( laughter ) It's pretty big.
Another one is there's an Indian company that came out
with a car called a Tata Nano. Again, it's a car.
It's not nano. But it's very small in
comparison to any other car. So in that sense, maybe Apple
had it all right. They had the regular iPod and
the had the little baby iPod called the Nano.
Did you have a question? >> Well, I've heard about
Bucky Balls. >> Mm-hmm.
I've heard that they can trap molecules of gas in them.
Oh, I hadn't heard that. But that would be a very cool
application. Do you have a question?
If carbon nanotubes can cross the blood-brain barrier,
couldn't they be used to help treat Tay-Sachs?
Maybe. I don't know if it would be
possible. But certainly, carbon nanotubes
have been investigated as possible therapies for different
brain disorders or diseases. >> So, definitely a lot of the
toxicology of nanoparticles is unknown.
And a lot of it is because not a lot of people are looking at it.
So when we talk about the sunscreens that have zinc oxide
and titanium dioxide nanoparticles in them, at this
point, as far as the FDA is concerned, zinc oxide and
titanium dioxide have been established as being safe
materials. Of course, when they did all of
those studies to establish that, they were using much, much
larger particles. And as we talked about earlier,
changing the size changes the properties.
And when I last read up on it, which has been a few months.
But within the last year, they weren't even sure at this point
if nanoparticles could be absorbed through your skin or
not. So even that level of research
was inconclusive. And I think in August, 2007,
there was a really good article in Scientific American, kind of
on this, you know, we need to be doing some research on the
possible impacts of nanotechnology now.
And specifically, they were talking about sunscreen.
So that would be something that if you were interested in
looking kind of where that is now, or at least within the last
year, you could look at that article.
When you talk about changing the particles, does that mean
combining nanoparticles and nano, tiny, tiny, together to
make a larger particle? What does it mean, to change a
nanoparticle? >> In the example of the
sunscreen, the reason that it's white is the particles, the
titanium dioxide compound, are big.
And so, when you start to make them even smaller, that's when
they lose their color. So the change is really taking
material that we know on a macro scale, at the sort of visible
scale, and making it small. And it's just the size change
that makes it behave differently.
Does that help to clarify? >> Are there nanoparticles in
vegetable matter? >> In vegetable matter?
So, right now, when we are talking about nanoparticles,
we're kind of talking about synthetic, man-made
nanoparticles. If you're getting into nature,
and you're talking about materials on the nano scale.
Molecules are on the nano scale. So then it becomes maybe
semantics as to what you're going to define as being a
nanoparticle or not being a nanoparticle.
Kind of what we're talking about now are non-natural
nanotechnologies. >> But they might be in nature
as well. >> There are things in nature
that are on the nano scale. For sure.
Is-- nanotechnology due to technologies for our generating
nanoparticles? Because you said that for a long
time that list that we're using. What is the reason for --?
I heard that one of the driving factors in
nanotechnology is that we constantly want electronics that
are smaller. And as we build chips made of
regular silicon as we showed on this, there's only so small we
can really go. So, as chips start to get
smaller, we needed to come up with new technologies.
And that sort of opened up the door for nanotechnology.
Also the development of instrumentation that allows you
to work on nano. >> Right.
That allows you to see things at the nano scale.
The scanning probe technologies that we were talking about.
So, yeah, people have been making nanoparticles since the
Medieval Ages, but they weren't able to study them, really.
So being able to do that makes a lot of difference.
And some of you may have already seen the little vials on
the table with the interesting black liquid in it.
You may notice that the liquid interacts with a magnet.
Can anyone think of another liquid that is magnetic?
That's because there really isn't any.
( laughter ) So I'm just going to show a
quick movie. You already have it
in front of you. But just another dramatic way
that using nanotechnology, we've been able to create these
magnetic liquids. And hopefully, technology--
It is liquid. Next slide.
Notice that we had a pool of the black liquid at the bottom.
I brought down the magnet, which is this dark thing.
And I think it's much better to see it when you're actually
using the vial. The resolution is much better.
So we see that the liquid is attracted to that magnet.
When the magnet is taken away, the liquid falls down the finger
of the apparatus. It turns out this liquid is
called Ferrofluid. It's something that NASA
invented in the 1960s, as a way to try to control liquids in
space. And what it is, it's just tiny
particles of magnetite or rust. We make these particles so
they're only 10 nanometers in size.
We coat them with something special called a surfactant.
It just keeps the magnetite particles from conglomerating
together and losing that nano scale behavior.
So you'll see that the magnet interacts with the black
Ferrofluid just like any old regular liquid.
It's a lot different than maybe those hairy Harry drawing
pictures, if you've ever played with iron filings.
It looks like a solid when you have even the tiniest of visible
iron filings. The current uses for this sort
of Ferrofluid is in stereo speakers to help damp the
external vibrations, so the music that you listen to sounds
a lot better. And even shock absorbers in
cars. You can tune, sort of the
viscosity of the degree of absorption in that
shock absorber by applying a magnetic field and changing
the way that the Ferrofluid is interacting there.
Some future use that's been suggested is, again, maybe
another example of targeted drug delivery.
If I can coat these nanoparticles with some sort of
drug, and then use a magnet to drag them through my body and
concentrate them in the part that I wanted the medication
to go. Just a few more examples
of other things that might be around.
Monolayers, which are just very thin layers.
Layers that are approximately a few nanometers in thickness
can really change the way that a surface interacts.
So this is where the self-cleaning windows come in.
Possibly being used on bake ware to increase the non-stickiness.
If you look at the top picture, you'll see that that bead of
water is not splattering out on glass like we're used to.
It's beading up and repelling that monolayer that we've laid
down. It turns out that these things
come from an inspiration in nature.
Again, we're still talking about nano sized features, as opposed
to special particles. The lotus leaf, or a kale leaf,
or a water lily, when you look at it and there's water on it,
the water beads up. It enables the leaf to clean
itself, because when the water rolls off, it can pick up some
dirt as it travels off. It turns out that this special
beading process comes from tiny, tiny bumps on the leaf.
So these tiny bumps prevent the water from being able to spread
out on it. It just sits on top of those
tiny bumps. And with this inspiration, we've
been able to develop coatings that mimic these tiny bumps.
So we have buildings, when you put the special Lotusan paint on
it, the water beads up and rolls off the dirt.
The same thing for water repellent wood.
So the wood on your deck isn't being soaked with water.
It's repelling the water that's pooling on it.
And then lastly, Nanotex fabrics.
So, Dockers has khakis, that if you spill wine on them, or get
any other dirt, the treatment that's on the fabric changes the
surface of the fabric so it doesn't stain.
But rather, the red wine just rolls right off.
And you can see that at the nano scale, these fibers look,
they're coated with something. That way, the liquids and other
stains interact with them and don't stick.
I'll just also make a plug. I know I've mentioned a bunch of
consumer products. And while I don't know the
technology behind every single consumer product out there,
there is an extensive Web site through the Woodrow Wilson
Center. I'll put that link up at the
end. That site has created a catalog
of where nano is in the products around you.
So I'll make sure to flash that up.
There are people out there looking into it.
And if you're concerned about it, you can go and look at the
catalog they've created. >> So I thought that in addition
to seeing some of the things that are maybe out as consumer
products that incorporate nanotechnology, it might be
interesting to have at least one example of some nanotechnology
research here at UW. And so Professor Tom Keuch, who
is in chemical engineering and I think physics, also, and some
grad students of his are doing some nanotechnology research
that has to do with solar cells. So just to give you a tiny bit
of background, the basic way that a solar cell works is that
it absorbs energy in the form of light.
It uses that energy to create a positive and negative charge
within a solar cell. Then, if you can get those
positive and negative charges to move to electrodes, you create
an electric current. And there's kind of some
competing issues in designing an effective solar cell.
First off, you want to be able to absorb as much energy as
possible. And so to do that, you want to
have a thick solar cell, with a lot of whatever material it is
that you're using to absorb that sunlight.
However, the thicker you make the solar cell, the more
difficult you make it for those positive and negative charges to
get to the electrodes. So in order for those charges to
make it to the electrodes efficiently, so that you can get
your electrical current, you want to have as thin a solar
cell as possible. So you want to simultaneously
have a thick and a thin solar cell in order to get good
efficiencies. And what they're trying to do
is to actually design an electrode where they have an
organic solar cell active layer. That's the part that absorbs the
sunlight and forms these positive and negative charges.
But then they're growing kind of nanopins, nanorods of zinc
oxide. And they're using that as the
electrode. And because these nanorods of
zinc oxide push up into the active layer, they reduce the
length that these positive and negative charges have to travel
in order to make it to an electrode.
So you can have a thicker absorbing layer, but without
having to worry about those positive and negative charges
having to go all the way through that layer to get to an
electrode. So you're kind of having a thick
and thin electrode at the same time.
And this is just a scanning electron micrograph, one of
those scanning probe microscopies we were talking
about earlier. This is an image of the zinc
oxide nanorods. You probably can't see this text
from where you're sitting, but this line here is indicating
that that distance is one micrometer in length.
So these are definitely down on the nano scale.
They're very, very tiny. And the hope is that using this
technology, we'll be able to make solar cells that are more
efficient and eventually cheap enough so that everyone can use
them in order to take advantage of solar energy generation
within their own homes and businesses.
And I think that's about all we have for you tonight.
Of course, we would be more than happy to take questions.
We've just listed a couple Web sites up here where you can go
and find more information on nanotechnology.
There's our Web site at the very top.
Also, there's a link here for the UW-Madison NSEC.
And if I try and say what NSEC is, I'll get it wrong.
It's the Nano Scale Engineering Center.
And the link that I've actually selected to put up there is one
of the groups that explicitly deals with risk and societal
implications. So that addresses some of the
concerns that were coming up regarding the consumer products.
And the name of some NanoCafes, that's actually a
local group that does kind of science talks, like we're doing
tonight, but on different nano topics.
The National Nanotechnology Initiative was the group that
Kim mentioned at the beginning, the government group that's
looking into funding and projections for nanotechnology.
And then, the last one is the Woodrow Wilson Center.
They have a list of different consumer products that
incorporate nanotechnology. So, with that, I think we're
done. ( applause )
Are there any lingering questions?
How do you make the nanoparticle sized zinc oxide?
How do they make these particular nanotubes?
In particular, the sunscreen. How do they pulverize it?
They don't pulverize it. There aren't really tools that
are small enough that you could easily pulverize things down to
the nano scale. At least not and get the size
distribution that you wanted. You'd have all different kinds
of sizes and dust that you would create.
They actually create them from, I guess, the bottom up is the
way you would put it. I don't know specifically for
zinc oxide, because I've never made it.
We do make silver and gold nanoparticles ourselves, though.
And it's just a chemical reaction that you control the
specific amounts of each reactant.
And then you usually stop the reaction as they're growing
bigger by capping those particles off with something
that's non-reactive. >> Do you start with a solution
of ions? >> Yep, a solution.
What would consider the two most important applications that
have come out of nanotechnology? >> Wow, I'm all over the
sunscreen. >> That's a million dollar
question. I think it's hard to choose.
There are so many. One of the reasons--
( inaudible ) I personally find the cancer
treatment with gold nanoshells pretty fascinating.
And also, there's a lot of research looking into water
purification and desalination of ocean water to provide fresh
drinking water for people who live in areas that don't have
it. So I think that has a tremendous
capability to impact a lot of countries who are without clean
water. >> I think also that Kim
mentioned that a lot of what's been driving nanotechnology
research is the computer industry.
And we didn't talk a lot about it tonight.
But a lot of the research has been going into making smaller
and smaller and smaller circuits.
And I think, providing that they can make it work, that's going
to be pretty important for our everyday lives.
What industry? >> The computer industry.
Yeah? >> Is there, I heard that you
could possibly buy the particles.
The Ferrofluid? You can.
It's available. I think it's called Teacher
Innovations. If you email me, or if you have
your dad email me, my business cards are out at the table, I
can give you the link. You can buy them.
It's definitely cool. >> We did.
We bought those. ( laughter )
Any other questions? Yeah?
If you're concerned about the safety of some of these things,
when you buy a consumer product will you know whether
nanotechnology has been used in it?
Like for example, fabrics. Is there concern that the
coating might absorb through your skin?
Would you know? >> At this point, you would,
because they're expensive, relatively speaking.
And they're generally proud of the fact that it's in the
fabric, and it's actively advertised on the tags, or
whatever. But no, not necessarily.
A lot of cosmetics are using nanotechnology right now.
You can get a little more sparkly eye shadow, and stuff
like that. And they're really not listing
that. >> It's definitely an
interesting regulatory issue. ( inaudible )
Yes. ( inaudible )
The situation in Washington is, there's been a lot of talk
creating the right definition of nano and what is going to be
considered nanotechnology. The FDA, I don't believe is
currently regulating it. The only agency that I know that
is starting to look into regulation is the EPA.
The EPA has recently started a voluntary regulation process for
companies who are producing these nanoparticles.
Industry is actually anxious to have something in place,
probably in response to the asbestos debacle, where
companies were making asbestos and it turned out to be very
harmful. And now companies are having to
pay out a lot of money in lawsuits.
So the problem, sort of the conundrum is that the materials
are generally already tested and shown to be safe.
But that's at the macro scale. It's a tricky issue.
But there's only one agency I know that's trying at this time.
Tom? >> When you were bouncing the
balls, how thin could you slice the amorphous metal before you
start to lose that property? You had it really thick.
Any idea of how many layers? >> How many layers you would
need? I don't know.
Thank you. ( inaudible )
No, and certainly, just to make another
plug for Science Expeditions. We'll be doing a bunch of tables
on nanotechnology, and also a science spectacular on stained
glass, where you can take home a piece of nano-stained glass if
you stop in. Great.
All right, well thank you so much.
Enjoy your evening. ( applause )