Robot eels, muscle shirts and other ways active matter will revolutionize the future

Brandeis physicist Seth Fraden explains what active matter is and how it can be used to create machines and materials that behave like living organisms.

Below is a transcript of the episode.

Hello, and welcome to this edition of the Brandeis University podcast, "The Take: Big Ideas Explained in Under 5 Minutes," where professors explain core concepts of their research in under five minutes.

Our topic today is active matter, a cutting-edge type of material that promises to revolutionize everything from consumer electronics, to medicine, to robotics, even the type of clothing we wear.

I'm Lawrence Goodman with the Office of Communications and my guest today is physicist Seth Fraden, who's part of Brandeis' Materials Research Science and Engineering Center, a.k.a. MRSEC, who’s doing some very groundbreaking work in the field of active matter.

Thank you for joining me.

Happy to be here, Lawrence.

HOST: Let's get the big picture first. What is active matter?

: Normal passive matter like a book lying on your table won't open the pages by itself and turn the pages. It's passive and sits there unless an external force acts on it. With active matter, you can take the internal energy and have that be converted into mechanical energy that can lead to self-propulsion.

HOST: And right now, active matter is only found in nature, right? Cells, for example. They move by generating their own energy.

FRADEN: But there's no reason why these kinds of active materials have to be constrained to the living. So we want to liberate this animation from the living and place it into the inanimate.

HOST: Some of our listeners may have heard of the movie Flubber where Robin Williams plays a professor who invents some miraculous elastic goo. You've said Flubber would be an example of active matter.

FRADEN: So, you have an ordinary Super Ball — when you bounce it, it will almost return to the height at which you drop it, and it will bounce a dozen times before it gradually loses its energy and comes to rest on the floor. Flubber, on the other hand, is a material that once you drop it, it bounces higher than the height at which you originally dropped it. And Flubber will bounce with increasingly greater speed with every interaction. So it's a material that contains its own energy source and uses that to propel itself with great velocity.

HOST: Okay, but Flubber is make-believe. So, can you give us a real-life example of what you're trying to do?

FRADEN: We imagine making clothing that you could wear a muscle suit that doesn't merely show the muscles underneath the skin but that contains within it the materials that would give you greater strength.

HOST: Any other practical applications?

FRADEN: The discovery and invention of self-pumping fluids. So you would add a little bit of this pixie dust to oil pipelines and it would propel the fluid within it rather than having an external pumping station.

HOST: You've also worked on creating a robotic eel that might one day swim through our bloodstream to deliver a drug to a cell or gene.

FRADEN: If you flay alive the eel and you peel off its flesh, you'll see muscles running down a spine. And along that spine is a series of neurons which innervate the muscles. And when an electrical wave propagates down the neurons, it causes the muscle along the eel to contract and then that eel will bend in a periodic, sinuous fashion.

So likewise, we create an extended network of chemicals that send a wave of chemical activity — if we embed that in a rubbery sheet and then we wrap this rubbery sheet around an elongated gel, and so that will contract and it will expand and swell in response to the chemical signals. When the chemical activity touches a certain piece of the gel, that gel contracts and so we get a wave of contractile motion traveling down the side of this gel.

HOST: And how will it get to a cell or gene?

FRADEN: It senses a chemical gradient or a chemical signal and then steers in that direction. That’s far beyond where we are at the moment.

The things that we imagine now are very likely to have no bearing on the marvelous things that will come out. And just as the pioneers of electromagnetism in the mid-1800s had no idea that you'd have motors or computers, electric lights, radios, telephones coming out of electricity, likewise, the things that I can speculate on now are very likely to be just mere shadows of what is possible.

HOST: And there you have it, active matter explained in under five minutes. You can find this podcast on iTunes, Spotify and SoundCloud so we hope you'll subscribe and keep listening to The Take: Big Ideas Explained in Under 5 Minutes.

Categories: Research, Science and Technology

Return to the BrandeisNOW homepage