Magnetic Micro-Robots

These are magnetic microrobots, just millimeters in size. They bend and move in response to applied magnetic fields. And with these magnetic fields controlled by a gaming controller, the micro robots can be driven carefully and precisely. They can turn by changing the direction of the magnetic field, roll in a rotating field, and even grasp and jump. It often feels like you're playing a video game.

In some previous work I did as a demonstration, I was pushing blocks of material around and using a micro robot like a bulldozer. And the demonstration I did was playing Tetris. The idea is this technique could be used to assemble human organ tissues by arranging blocks of different types of cells in particular patterns.

The way these scientists actually fabricate the micro robots is pretty ingenious. Tiny rare earth magnets are magnetized in a strong magnetic field. Then they're mixed into a UV resin that will harden when exposed to UV light. The mixture is poured into a mold and placed on a stage below, which is a rotatable permanent magnet. This creates an adjustable magnetic field to which all the tiny magnets in the resin align. When the desired orientation is reached, UV light cures the resin in one particular spot, locking those magnets in place. Then the magnetic field can be adjusted, and the next section cured. Ultimately, the result is a flexible device with embedded magnets that have different orientations depending on where they are. This pattern of orientations is what gives these micro robots their unique behavior in response to magnetic fields.

If we can point multiple compass needles in opposite directions within a flexible device, if we apply the field vertically, those compass needles will both try to orient and align with that applied field. With the right magnetic fields, the results can be pretty sophisticated. Watch this micro robot pick up a block and then roll with it over to a ramp. It rolls up the ramp, deposits the block at the top, and then returns to its original position. The idea is that devices like this could be used in medical applications. So this could be sending a device into fluid areas in your body or into your gastrointestinal tract.

For example, a capsule that you could swallow which will go passively through your GI tract, have no wires attached, and at the right moment, we can activate a sampling chamber, basically to open up and take samples of either stomach or small intestine contents, take biopsy samples of the intestinal wall. But grippers like these may not be the only magnetic microrobots invading your body. A different research group has pioneered these even smaller peanut-shaped magnetic particles. And under the right magnetic field conditions, they form swarms.

This swarm can take on different configurations: the vortex, where many particles travel together like a school of fish, the chain, where particles line up and travel single-file, and the ribbon, where motion is perpendicular to the line of particles. One potential application of micro robotic swarms is drug delivery. Each magnetic particle could carry a small amount of drug and be guided toward the intended drug delivery site.

So to make a swarm useful for essential biomedical applications, you'd like to keep the swarm aggregated. You probably will not be able to see single micrometer-sized particles, but you could see the entire swarm. So you'd like to keep it aggregated so you can move it and keep track. But then going through tight environments, for example, going through blood vessels, if your swarm, the overall swarm size is bigger than the blood vessel, then it doesn't fit. So you need to line them up and squeeze through, so that's the motivation for being able to control the shape of the swarm. And, who knows, one day you might have swarms of magnetic microrobots cleaning your teeth.

Another group of researchers has used tiny magnetic robots to clear biofilms - those are communities of bacteria and the protective sugar polymers around them. They typically build up on medical devices, the insides of pipes, and on teeth. Can I ask, does this idea of magnetic control of micro robots, does it supplant previous concepts? Like I'm trying to conceptualize this in terms of like you know sci-fi futures with nanobots where I imagine you know we imagine these things as really self-contained and you know powering themselves around the body and that sort of stuff.

Yeah, great question. So the advantage of magnetic fields is that it's a very scalable technique. So we can make magnetic microbots that are single cell size and we can make them that are centimeters in size and the principles behave similarly. It pulls off a lot of the functionality to off-board magnetic coils. We can have a big computer sitting there and power supply. It's a lot of the hard aspects of driving a robot we can do as traditional size. You can have a big computer. We can have medical imaging hooked up and do all these things off board. And then on board, we're just transmitting the magnetic field directly to the device and so this our micro robot is basically then just like the mechanical hand of the robot and the rest of the robot is really sitting on the table beside the patient.

Hey, this episode of Veritasium is supported by viewers like you on Patreon and by Audible. There's no better place to listen. Listening makes us smarter, more connected people. And there's no better time to start listening than right now with a 30-day trial and your first audiobook plus two Audible originals free when you go to audible.com slash veritasium or text veritasium that's V E R I T A S I U M to 500 500.

Now if you're looking for something good to listen to, might I recommend "How to Change Your Mind: What the new science of psychedelics teaches us about consciousness dying, addiction depression and transcendence" by Michael Pollan. This is a fascinating book and it's narrated by the author himself. I'm actually listening to it at the moment and he may be changing my mind about the very nature of consciousness. What I find so incredible is how recent this scientific field is and what it's revealing about how all of our brains work.

Now when I'm listening to books like this, I actually look forward to getting stuck in traffic. I find it reduces my stress levels because I'm learning something rather than just wasting time in the car. Now, the way it works with Audible is that as a member, you can choose three titles each month: one audiobook and two Audible originals that you can't hear anywhere else. And if you don't like a book, you can exchange it no questions asked, and the books you get are yours to keep. You can go back and re-listen anytime, even if you cancel your membership. Just go to A U D I B L E dot com slash veritasium or text veritasium to five hundred five hundred and browse their unmatched selection of audio content.

So I want to thank Audible for supporting me and I want to thank you for watching.