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I want to tell you today about three areas
of science and engineering

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that I think are converging
in very interesting ways.

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I'm a mechanical engineer.

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I've been working in robotics
for over 25 years.

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I've been in micro/nanotechnologies
for over 15 years.

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And over the past decade,
since I've been here in Zurich,

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I've been working more closely
with biologists and with medical doctors,

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and I think that the technologies
we're working on

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and our vision of the future
has some very interesting implications.

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But instead of telling you about it,

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what I want to show you
is a clip from a Hollywood film

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that actually happens
to be almost as old as I am, so ...

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(Video) Man: All stations, stand by.

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(On stage) (Laughter)

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(Video) Man: Right. Inject.

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(On stage) "Fantastic Voyage,"
it's a classic.

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I love this movie.

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Hollywood has two advantages
when they make movies, versus an engineer.

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They don't have to worry about physics.

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They don't have actually
have to make the things.

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What I want to show you now

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is an animation actually made for us
by the Discovery Channel.

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They visited my lab
about a year and a half ago.

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We appeared on one of their shows,

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and they put together this concept
of where we're heading.

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And what we've been working on
for several years now

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have been little, what we call microrobots
that we inject into your eye -

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we haven't done it on a human yet,

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but we inject it into your eye -

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and we use magnetic fields
to guide that device back to the retina

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to perform certain retinal therapies,
for instance delivering drugs.

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You saw there, over the patient,

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the sequence of electromagnetic
coils that we use.

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This is in a real pig's eye
that you're seeing right here.

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This pig's eye came from the butcher
earlier that morning,

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so we didn't harm any animals
ourselves in making this, but -

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(Laughter)

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What you see is that we're able
to very precisely control that device.

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That device is about 0.5 mm in size,

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about a millimeter long,
to give you an idea of scale.

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And in this next slide,

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you'll see on the left is a system
of electromagnetic coils we use.

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We do in vivo animal trials with these.

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There are eight of these coils,

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we call it the OctoMag,

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and we control the current
in each one of those very precisely

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to guide this device
through the ocular cavity

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back to the retina.

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You'll see one of our most recent devices
on the fingertip there.

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That particular, we call it a microrobot;

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it's about 1/3 mm in diameter, 
330 microns in diameter.

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And our design specs -

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the reason we want it to be so thin -

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it's about 1.8 mm long -

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is that we want it to fit
inside of a 23-gauge needle.

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If it fits inside of a 23-gauge needle
and we inject it into your eye,

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as we remove that, that puncture wound
doesn't need a suture.

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It's relatively non-invasive.

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You just put a little topical
anesthetic, and it's done.

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All the time to inject drugs to treat
age-related macular degeneration -

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that needle, not the microrobots,

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I should say.

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But that robot that I just showed you,
that you see there on the fingertip,

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is the biggest robot we make.

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My goal is to make robots that are
about 1000 times smaller than that,

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something the size, for instance, 
of these E. coli bacteria.

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These little rod-shaped bacteria 
are about a micron or two long.

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That is about 1/100
of the width of a hair.

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See those little tails coming off of them?

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We'll get to that later, okay?

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But before we start talking
about bacteria,

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I want to talk a little bit about physics
and what these constraints put on us,

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so we're going to do 
a simple thought experiment here.

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Let's take a cube, okay?

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It's a meter on the side.

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And I don't need my calculator
to do this calculation.

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A meter by a meter by a meter
is a cubic meter, right?

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But if I take that cube
and I shrink it to 10 cm -

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I shrink it by a factor of 10 -

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that calculation changes

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because I'm taking a length
by a length by a length,

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and all of a sudden, it's become
1/1000th of its original volume,

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and so properties that depend on volume -

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for instance, mass -

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also go down by a factor of 1000.

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Now, if I go down another
100 times, to a centimeter,

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it's gone down, now, by a million times.

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And so volume -

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as I said, the weight of it
goes down by a million times,

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but also those magnetic forces
we generate on it are also going down

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because they scale also
with the mass of the object.

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So you might say, "But since
it weighs less, what's the problem?"

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But now, let's think
about the surface area of that cube.

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It's got six sides,
each side is a square meter.

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It's got six square meters on that cube.

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Over the volume of one, ratio of six.

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But as I go down, that area
is only a length by a length,

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and so as I go down each order
of magnitude by a factor of 10,

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the importance of surface area
goes up by a factor of 10.

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And that causes problems, okay?

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I can't make robots

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and guide them with magnetic fields
the way I showed you in the eye -

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I can't make them any smaller than I have.

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So what are some of the implications?

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Well, think about a fish
and how a fish swims.

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A fish moves its tail back and forth
in a reciprocal motion.

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It's pushing the mass of fluid back
and moving itself forward.

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It knows Newton's first law, okay?

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And so, Geoffrey Taylor, 
professor at Cambridge,

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thought about this and published
some very important papers in the 1950s,

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and he made a little mechanical fish
just to show how it would work in water,

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and it swims just the way
you'd think it would.

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But if I took that fish

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or I took you, and I made you
1,000 or 10,000 times smaller,

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and I put you in water,
all of sudden, that water would feel -

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even though it has the same viscocity,

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the surface effects
or the drag of that water

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would be much, much stronger on you.

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And so what Geoffrey Taylor did -

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this is a video he made in the 1960s -

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is he got a vat of something very thick.

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I think if you're from the UK, 
you know Lyle's Golden Syrup,

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and I think that's what
he must have used if you look at it.

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So, he took his robot -

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it's a little mechanical fish -

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put it in there,
and it doesn't go anywhere

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because the fluid drag is so strong

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and the mass that's pushing back
is so much less than that

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that it doesn't move.

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And that's the problem
as we go down in scale,

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is that we have to rethink 
the way things swim

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and the way things move.

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Well, if you're an engineer
and you don't know how to solve a problem,

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what do you do?

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You look at nature and think,
"How did nature solve this problem?"

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Nature solved this problem
millions, billions of years ago.

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We know there's paramecia.

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You see the spermatozoa
there on the right?

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And they have these special
little hairs on them, these cilia,

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these flagella
for the sperm, we call them,

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that move in very interesting ways.

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Now, nobody knew before 1675
that these things even existed.

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Antonie van Leeuwenhoek, in Holland, 
was looking in his microscope,

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and he was astounded

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to see a world of tens of thousands
of little microorganisms swimming,

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and he wrote a letter
to the Royal Society the next year.

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They verified his results.

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People were astounded, what was going on.

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And what van Leeuwenhoek
saw in his microscope

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was the first time
anybody had ever seen bacteria.

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This is a graphic
of one of the rod-shaped ones.

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It's about a micron or two long.

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And as you look at these
under a microscope -

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you saw the one I showed of the E.coli -

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you'll notice it has
a little flagella on it.

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And as you look at it under a microscope,

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what you see is this flagella
seems to be wiggling back and forth,

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but if you were able to look at it
from another direction,

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you realize it's not wiggling
back and forth; it's actually rotating.

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And Howard Berg,

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when he was at University of Colorado
in the early 1970s, discovered this,

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and what he discovered was astounding:

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nature has invented a rotary motor.

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Think about it.

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Where else in nature
is there a rotary motor?

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And Howard has been to our lab
and given us some advice on what to do.

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He calls these things
nature's microrobots, okay?

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So the body of the bacteria
has sensors on it, chemoreceptors.

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Those chemoreceptors communicate
with the motor in the back of it,

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to drive it.

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That also has software in there.

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The software is the chunks
of DNA floating around.

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They're just telling it
what parts to make

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to keep building the sensors it needs,
the motors it needs, and all that.

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And the motor is a fascinating structure.

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Since Howard discovered
these bacterial motors in 1973 -

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which, by the way some people believe
is evidence of an intelligent designer,

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but I don't think
most biologists believe that.

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These motors are made
from about 30 to 40 proteins.

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They assemble into this structure

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that spins up to
160 revolutions per second.

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And you see on the right here,
a video from Howard's lab

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of fluorescent bacteria
swimming at these speeds.

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Remember that the size of these
is a micron or two.

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So we looked at this, 
and we were thinking,

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"What can we learn from this?

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How can we take advantage of this?"

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So we leveraged some
of our nanotechnology experience

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to build something we called 
an artificial bacterial flagella.

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Now, I can't make that motor yet.

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That motor's about
45 nanometers in diameter.

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But what I can make is the flagella

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of a similar size and shape
that a bacteria has.

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And on the front of it there on the left,
you'll see what looks like a head,

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and what that is is actually
a little piece of magnet,

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and what I can do with that magnet

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is I can generate a torque on it
with a magnetic field,

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and as I rotate that field -

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and these are very, very low fields;

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they're about 1000 times
less than an MRI field -

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they start to get it to twist,

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and as it twists,
it propels itself forward,

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just like E. coli do.

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To give you an idea of the scale
we're talking about,

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here's a scanning electron
micrograph of a human hair;

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it's about 100 microns or so in diameter.

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There is the size of our smallest ABFs.

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They're about 10 microns,
these particular ones.

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And this is the size
of a red blood cell, okay?

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So we're about double.

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Our smallest ones are
about twice the size of a red blood cell.

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And here are three of them swimming
together in a sort of swarm behavior.

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To me, they look alive.

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I get excited when we do this, you know?

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(Laughter)

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That's why I do robotics.

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There's nothing more fun than building
a machine and watching it move.

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Now, you'll notice
these will start to go backwards.

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I didn't reverse the video;
I just reversed the field.

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There's some really interesting
fluid dynamics to be explored here,

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and that's pretty interesting.

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One exciting thing for us this year
was when we were in the bookstore,

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we picked up a copy of
the 2012 Guinness Book of World Records

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and discovered that we were
in the Guinness Book of World Records

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for the smallest medical robot.

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(Audience) Whoo!

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Bradley Nelson: Being in the
Guinness Book of World Records is great,

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but what I'm really gunning for is,

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I want to win a medal
in the next Olympics,

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and so we're developing
synchronized swimmers.

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(Laughter)

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These are interesting -

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What's particularly interesting
about these guys

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is that they're made out of a polymer.

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They're noncytotoxic.

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They don't kill cells;

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in fact, cells like to grow on them.

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And we've developed a new technology

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that allows us to make
some fairly arbitrary shapes here.

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So in this next little video
I want to show you

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is one of our devices.

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We put a claw on it,

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and so what it can do is go around
and grab these little -

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these are 6-micron diameter beads,

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so they're about the size
of that red blood cell -

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grab those, move them up in 3D, 
move them up and down,

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and then eventually release them
using these fluidic forces.

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We've also been thinking about other,
more serious applications as well.

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Here's one of our devices.

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We coated it with
a fluorescent molecule called calcein.

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This molecule, you're looking at it 
in a fluorescent microscope there.

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This molecule, actually,

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is the same molecular weight
as a lot of chemotherapy drugs.

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And on the left, you'll see 
some red cells that are stained red.

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We discovered as we moved this bacteria
near those cells and touched them with it,

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the calcein actually
gets taken up by the cells.

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So this allows us, now, to potentially
deliver drugs into individual cells

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and target individual cells
with this kind of technology.

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The other thing that's cool -

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I've only shown you a few, 
but we can make armies of these.

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We can make them by the thousands.

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We can make about one a second.

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We make tens of thousands, 
put them in suspension.

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So I think there's some interesting
possibilities here

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for the future of where this can go.

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So let's go back to the bacterial motor.

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This is a video from
Keiichi Namba's lab at Osaka University.

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He and his group have spent years

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trying to understand
the exact sequence of proteins,

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how they assemble into this rotary motor.

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And while I'm not at the point
where I can develop the motor,

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I can develop some of these
parts of this device,

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and so what we're hoping as we move into
the future and keep going in this area,

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we'll learn more and more from nature
at these molecular scales

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and be able to build machines
that operate in similar ways

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and under similar principles.

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I've been very fortunate
to work with some brilliant scientists,

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brilliant medical doctors,

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and when you're at the ETH,

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the Swiss Federal Institute
of Technology here -

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you know, I'm an engineer.

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I walk the hallways where people
like Conrad Röntgen, who invented X-rays,

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Wolfgang Pauli or Albert Einstein were.

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It's a humbling experience.

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So I take a little bit of comfort

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in a quote from a famous
aeronautical engineer from Caltech,

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Theodore von Karman,

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and von Karman said,

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"The scientist describes what is; 
the engineer creates what never was."

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(Laughter)

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Okay. So.

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I want to leave you
with one last thought here.

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This is from Richard Feynman,
the famous physicist from Caltech,

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who said, "What I cannot make, 
I do not understand."

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(Laughter)

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Okay. So thank you very much.

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(Applause)