Tiny robots with giant potential | Paul McEuen and Marc Miskin


Translator: Joseph Geni
Reviewer: Camille Martínez Mark Miskin: This is a rotifer. It’s a microorganism
about a hair’s width in size. They live everywhere on earth —
saltwater, freshwater, everywhere — and this one is out looking for food. I remember the first time
I saw this thing, I was like eight years old
and it completely blew me away. I mean, here is this
incredible little creature, it’s hunting, swimming, going about its life, but its whole universe fits
within a drop of pond water. Paul McEuen: So this little rotifer
shows us something really amazing. It says that you can build a machine that is functional, complex, smart, but all in a tiny little package, one so small that
it’s impossible to see it. Now, the engineer in me
is just blown away by this thing, that anyone could make such a creature. But right behind that wonder,
I have to admit, is a bit of envy. I mean, nature can do it. Why can’t we? Why can’t we build tiny robots? Well, I’m not the only one
to have this idea. In fact, in the last, oh, few years, researchers around the world
have taken up the task of trying to build robots that are so small that they can’t be seen. And what we’re going
to tell you about today is an effort at Cornell University and now at the University of Pennsylvania to try to build tiny robots. OK, so that’s the goal. But how do we do it? How do we go about building tiny robots? Well, Pablo Picasso, of all people,
gives us our first clue. Picasso said — [“Good artists copy,
great artists steal.”] (Laughter) “Good artists copy. Great artists steal.” (Laughter) OK. But steal from what? Well, believe it or not, most of the technology you need
to build a tiny robot already exists. The semiconductor industry
has been getting better and better at making tinier and tinier devices, so at this point they could put
something like a million transistors into the size of a package
that is occupied by, say, a single-celled paramecium. And it’s not just electronics. They can also build little sensors, LEDs, whole communication packages
that are too small to be seen. So that’s what we’re going to do. We’re going to steal that technology. Here’s a robot. (Laughter) Robot’s got two parts, as it turns out. It’s got a head, and it’s got legs. [Steal these: Brains] (Laughter) We’re going to call this a legless robot, which may sound exotic, but they’re pretty cool all by themselves. In fact, most of you have
a legless robot with you right now. Your smartphone is the world’s
most successful legless robot. In just 15 years, it has
taken over the entire planet. And why not? It’s such a beautiful little machine. It’s incredibly intelligent, it’s got great communication skills, and it’s all in a package
that you can hold in your hand. So we would like to be able
to build something like this, only down at the cellular scale, the size of a paramecium. And here it is. This is our cell-sized smartphone. It even kind of looks like a smartphone, only it’s about 10,000 times smaller. We call it an OWIC. [Optical Wireless Integrated Circuits] OK, we’re not advertisers, all right? (Laughter) But it’s pretty cool all by itself. In fact, this OWIC has a number of parts. So up near the top, there are these cool little solar cells
that you shine light on the device and it wakes up a little circuit
that’s there in the middle. And that circuit can drive
a little tiny LED that can blink at you and allows
the OWIC to communicate with you. So unlike your cell phone, the OWIC communicates with light, sort of like a tiny firefly. Now, one thing that’s pretty cool
about these OWICs is we don’t make them one at a time, soldering all the pieces together. We make them in massive parallel. For example, about a million
of these OWICs can fit on a single four-inch wafer. And just like your phone
has different apps, you can have different kinds of OWICs. There can be ones that, say,
measure voltage, some that measure temperature, or just have a little light that can blink
at you to tell you that it’s there. So that’s pretty cool,
these tiny little devices. And I’d like to tell you about them
in a little more detail. But first, I have to tell you
about something else. I’m going to tell you a few things
about pennies that you might not know. So this one is a little bit older penny. It’s got a picture of
the Lincoln Memorial on the back. But the first thing you might not know, that if you zoom in, you’ll find
in the center of this thing you can actually see Abraham Lincoln, just like in the real Lincoln Memorial
not so far from here. What I’m sure you don’t know, that if you zoom in even further — (Laughter) you’ll see that there’s actually
an OWIC on Abe Lincoln’s chest. (Laughter) But the cool thing is, you could stare at this all day long
and you would never see it. It’s invisible to the naked eye. These OWICs are so small, and we make them in such parallel fashion, that each OWIC costs actually
less than a penny. In fact, the most expensive thing
in this demo is that little sticker that says “OWIC.” (Laughter) That cost about eight cents. (Laughter) Now, we’re very excited about
these things for all sorts of reasons. For example, we can use them
as little tiny secure smart tags, more identifying than a fingerprint. We’re actually putting them inside
of other medical instruments to give other information, and even starting to think about
putting them in the brain to listen to neurons one at a time. In fact, there’s only one thing
wrong with these OWICs: it’s not a robot. It’s just a head. (Laughter) And I think we’ll all agree that half a robot
really isn’t a robot at all. Without the legs,
we’ve got basically nothing. MM: OK, so you need the legs, too,
if you want to build a robot. Now, here it turns out
you can’t just steal some preexisting technology. If you want legs for your tiny robot,
you need actuators, parts that move. They have to satisfy
a lot of different requirements. They need to be low voltage. They need to be low power, too. But most importantly,
they have to be small. If you want to build a cell-sized robot,
you need cell-sized legs. Now, nobody knows how to build that. There was no preexisting technology
that meets all of those demands. To make our legs for our tiny robots, we had to make something new. So here’s what we built. This is one of our actuators,
and I’m applying a voltage to it. When I do, you can see
the actuator respond by curling up. Now, this might not look like much, but if we were to put a red blood cell
up on the screen, it’d be about that big, so these are unbelievably tiny curls. They’re unbelievably small, and yet this device can just bend
and unbend, no problem, nothing breaks. So how do we do it? Well, the actuator is made
from a layer of platinum just a dozen atoms or so thick. Now it turns out, if you take
platinum and put it in water and apply a voltage to it, atoms from the water
will attach or remove themselves from the surface of the platinum, depending on how much voltage you use. This creates a force, and you can use that force
for voltage-controlled actuation. The key here was to make
everything ultrathin. Then your actuator is flexible enough to bend to these small
sizes without breaking, and it can use the forces that come about from just attaching or removing
a single layer of atoms. Now, we don’t have to build these
one at a time, either. In fact, just like the OWICs, we can build them massively
in parallel as well. So here’s a couple thousand
or so actuators, and all I’m doing is applying a voltage, and they all wave, looking like nothing more than the legs
of a future robot army. (Laughter) So now we’ve got the brains
and we’ve got the brawn. We’ve got the smarts and the actuators. The OWICs are the brains. They give us sensors,
they give us power supplies, and they give us a two-way
communication system via light. The platinum layers are the muscle. They’re what’s going
to move the robot around. Now we can take those two pieces,
put them together and start to build our tiny, tiny robots. The first thing we wanted to build
was something really simple. This robot walks around
under user control. In the middle are some solar cells
and some wiring attached to it. That’s the OWIC. They’re connected to a set of legs
which have a platinum layer and these rigid panels that we put on top that tell the legs how to fold up,
which shape they should take. The idea is that by shooting a laser
at the different solar cells, you can choose which leg you want to move and make the robot walk around. Now, of course, we don’t build those
one at a time, either. We build them massively
in parallel as well. We can build something like one million
robots on a single four-inch wafer. So, for example, this image
on the left, this is a chip, and this chip has something like
10,000 robots on it. Now, in our world, the macro world, this thing looks like it might be
a new microprocessor or something. But if you take that chip
and you put it under a microscope, what you’re going to see are
thousands and thousands of tiny robots. Now, these robots are still stuck down. They’re still attached to the surface
that we built them on. In order for them to walk around,
we have to release them. We wanted to show you how we do that live,
how we release the robot army, but the process involves
highly dangerous chemicals, like, really nasty stuff, and we’re like a mile
from the White House right now? Yeah. They wouldn’t let us do it. So — (Laughter) so we’re going to show you
a movie instead. (Laughs) What you’re looking at here
are the final stages of robot deployment. We’re using chemicals to etch the substrate
out from underneath the robots. When it dissolves, the robots are free
to fold up into their final shapes. Now, you can see here,
the yield’s about 90 percent, so almost every one of those
10,000 robots we build, that’s a robot that we can
deploy and control later. And we can take those robots
and we can put them places as well. So if you look at the movie on the left,
that’s some robots in water. I’m going to come along with a pipette, and I can vacuum them all up. Now when you inject the robots
back out of that pipette, they’re just fine. In fact, these robots are so small, they’re small enough to pass through
the thinnest hypodermic needle you can buy. Yeah, so if you wanted to, you could inject yourself full of robots. (Laughter) I think they’re into it. (Laughter) On the right is a robot
that we put in some pond water. I want you to wait for just one second. Ooop! You see that? That was no shark.
That was a paramecium. So that’s the world
that these things live in. OK, so this is all well and good, but you might be wondering at this point, “Well, do they walk?” Right? That’s what they’re supposed to do.
They better. So let’s find out. So here’s the robot and here
are its solar cells in the middle. Those are those little rectangles. I want you to look at the solar cell
closest to the top of the slide. See that little white dot?
That’s a laser spot. Now watch what happens
when we start switching that laser between different
solar cells on the robot. Off it goes! (Applause) Yeah! (Applause) Off goes the robot
marching around the microworld. Now, one of the things
that’s cool about this movie is: I’m actually piloting
the robot in this movie. In fact, for six months, my job was
to shoot lasers at tiny cell-sized robots to pilot them around the microworld. This was actually my job. As far as I could tell, that is
the coolest job in the world. (Laughter) It was just the feeling
of total excitement, like you’re doing the impossible. It’s a feeling of wonder like that first
time I looked through a microscope as a kid staring at that rotifer. Now, I’m a dad, I have a son of my own,
and he’s about three years old. But one day, he’s going to look
through a microscope like that one. And I often wonder: What is he going to see? Instead of just watching the microworld, we as humans can now build
technology to shape it, to interact with it, to engineer it. In 30 years, when my son is my age,
what will we do with that ability? Will microrobots live in our bloodstream, as common as bacteria? Will they live on our crops
and get rid of pests? Will they tell us when we have infections,
or will they fight cancer cell by cell? PM: And one cool part is, you’re going to be able to participate
in this revolution. Ten years or so from now, when you buy your new iPhone 15x Moto
or whatever it’s called — (Laughter) it may come with a little jar
with a few thousand tiny robots in it that you can control
by an app on your cell phone. So if you want to ride
a paramecium, go for it. If you want to — I don’t know —
DJ the world’s smallest robot dance party, make it happen. (Laughter) And I, for one, am very excited
about that day coming. MM: Thank you. (Applause)

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