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)
