The brilliance of bridges and roads that repair themselves | Mark Miodownik

0:06You're listening to TED Talks Daily, where we bring you new ideas to spark your curiosity every day. I'm your host, Elise Hu. Over the thousands of years of human existence, we've come to master the art of making things. But we haven't gotten quite so good at taking care of the things we make. So how do we do that? Taking inspiration from nature's ability to heal and adapt. Materials scientist Mark Miodovnik envisions a future of animate materials that can self-repair, self-recycle, and even self-grow. It's a possibility that could revolutionize our infrastructure and reduce waste.

0:54If you come and visit me in London, you'll see streetscapes a bit like this. Hey, it's Elise here, and I want to quickly describe the image that just came up on the screen behind Mark. It's a shot of a street in London. You see the iconic red telephone box with the glass windows, concrete sidewalk, a road on one side and businesses on the other, one with a blue facade. There are a few people walking by in coats. And if you see the world through my eyes, you'd see this. Mark has changed the slide and we see the same picture, but this time it's got lots of annotations and markings on it. He has circled the various materials in the image, glass, concrete, asphalt, and he's named them.

1:43We see words like steel, rubber, tarmac, wood, PVC, and more. Don't pity me, okay? I love this stuff. We just make so many amazing materials as humans. In fact, that's what we do. We have done that for thousands of years. We make stuff. At the first, we made tools, which allowed us to make clothes. And then it allowed us to make shelter to protect us from storms and from the weather. And containers allowed us to store food so we could survive the winters. And then we started to dream big. We started to make boats. And we started to make materials that cured toothache. And we made stuff that could harness electricity.

2:28We made airplanes. And we made stuff that could go to the moon. I mean, this is who we are. We make stuff. Why do we make so much stuff? Well, it represents who we are. This is who humans are. We like to make stuff. We like to dream big. We like to create. So that is why civilization gets pushed forward. It's why the ages of civilization are named after materials. We have the Stone Age. We have the Copper Age. We have all the ages until now. But there's a problem. You're all familiar with an image of a pothole. You've all driven straight into a pothole or, you know, on a bike, been thrown off your bike by hitting one of these potholes.

3:10They're a menace. If you're on an e-scooter, you just disappear right down them.

3:18All of our stuff, we've got so good at making it, but we're not so good at repairing it. We're not so good at taking care of it. And that is our next big task, our next adventure as humans. So what would a future like that look like? Imagine a city now with a future, but imagine one that doesn't constantly fall apart, that doesn't constantly have potholes and cracks in bridges, that when a storm hits and a small, it's damaged, then it heals itself. What would that be like? Could we do it? Can we make bridges, tunnels, roads, buildings that repair themselves? The answer is some stuff called animate matter.

4:00And what is animate matter? Well, animate matter is a different form of material. We're borrowing from nature. It's a form of material that repairs itself, heals itself, actuates, senses the environment. Is it impossible to make? No, we're making it now. People in my lab, hundreds of people in labs all over the world are making this stuff called animate matter. But to tell you how it works, I first need to take you inside materials. I need to show you how they work. So this is how we material scientists understand the material world. This is how we design new materials. You've got big stuff at the top, and you get smaller, smaller, smaller, smaller, smaller.

4:42So you can see the natural world, how nature builds materials. you have trees, and then you have whales, and they have mice, and then you have fleas on the mice, and they have hairs on the fleas. And inside those you have tissues. And there are many types of tissues. We have skin tissue, lips, we have brain tissue. Then you zoom in further, you get single cells. And then you zoom in further, and you get the whole molecular machinery of cells. And you zoom in further, and you get the DNA. And it's the DNA that builds those machines, and the machines that build the cells and cells build the tissues.

5:13And so you get the idea. The way nature builds materials is that it stacks every layer on another, that they are all grown inside each other. Big stuff contains small stuff. We are multi-scale materials. And what is life then? What is it to be alive? Well, it's the connection between those scales. The scales themselves are physics and chemistry. But the stuff that connects them, the information, they check each other, they repair each other. If they find some damage, they repair that. And you're doing it now, right? You are repairing yourself now. You get a scratch, your body just goes to work repairing it.

5:54So nature builds materials, but it builds self-repaired materials. Now, we've built materials too, we build amazing materials, massive bridges, cars, phones. We've mastered these different scales. We can zoom in, we can make nanostructures, we can manipulate atoms, we can make transistors. But what we really lack is the ability to connect those scales up and get them to self-repair. And that is the big next challenge. Can we do it? Well, look, let me take you through some work that we're doing that we're already making great progress. So self-repairing roads. When we analyze the roads, we realize that big potholes start off as tiny microscopic cracks.

6:31And the key to stopping them doing runaway growth into a pothole is to catch them early. If you zoom in now and we started to look at the different structures inside roads, what we found are maltines and micelles, and actually they can self-repair. They actually can move around, but you need to give them impetus. You need to give them energy. So we put embedded nanoparticles into that material, and by actuating with magnetic fields, we can get them to move around and self-repair the micro cracks before they become potholes. Another example, self-repairing concrete. There are people in the world who've been making this for quite a while now.

7:09You can buy this stuff. How does it work? Well, inside the concrete are tiny microorganisms placed there by the concrete manufacturers. When a big storm hits and a crack opens up, the microbacteria wake up. They smell the humid air. They look around for food. They find starch that's been left there by the designers of the concrete. They eat it. They do a poo, and they poo calcite. Yes! They eat their way out of the crack, leaving pristine material behind them and restoring the concrete to 90 % of its original strength. It works today. Self-disassembling plastic. So we've been working on this problem that you need to put plastic wrappers around small seedlings to grow trees to reforest the world.

7:53But the problem is the plastic itself then pollutes the world. So can we get a material that protects the tree for years on end, but when that tree is mature, will then disintegrate and become biodegradable? Answer, yes. We are embedding little tiny enzymes that catalyze the disassembly of those polymers, of those plastics. And we get them into the plastic by wrapping them in a random heteropolymer. And that allows them to survive the process, the high temperature process of making the plastic, and to survive in the environment until they're needed. And then they come out and it disintegrates.

8:29And we're field testing this now. So these animate materials I'm talking about, they are really extraordinary and they are possible now. We are making them. And they make self-repairing roads, self-repairing bridges, and biodegradable materials much more tangible in the future. So what are the problems we face? It's not so much the technical stuff. We can do the technical stuff. Probably one of the biggest hurdles is the economics. At the moment, we have a system where we make stuff, it falls apart, we remake it, it falls apart. And we throw the waste away into the environment. We do this with roads, we do this with buildings, we do this with electronics, we do this with clothes, we do this with pretty much everything.

9:11and we're basically just piling our materials, our wonderful materials, the ones that we've made over time immemorial, we just throw them away as if we don't care. And we've got to stop. We've got to take care of our materials, but we need a new economic model. The consumerist model doesn't work for a sustainable future, for a non-polluting future. And I think animate materials will play a really big part in making those future. And when you calculate the cost of that pollution and that global warming, then they'll start to make sense economically. So what would we feel like, though, to live in this world, to live in a world that is animate?

9:53Well, I think in 20 years' time, you come to visit me in London and the animate materials are now in the infrastructure and in our phones and in our laptops. I don't think it will feel weird. I think it will feel a bit like being in a forest, right? You go into a forest, all of that stuff is looking after itself, repairing itself, building itself. In fact, we could push these animal materials to make themselves. Perhaps we could make roads that build themselves. And then what would our job be? Our job wouldn't be to constantly have to repair things, laboriously throw things away, remake them. Our jobs would be more like gardeners, right?

10:35Yeah, the city would look after itself. We could enjoy ourselves, occasionally pruning a road, that was drifting off into the wilderness. Yeah? Or it had rebuilt a bedroom of yours and you didn't quite like the design. You could push back on it a bit. But that is the world we're heading towards. That's the future. A future where we take care of our stuff. Thank you. Thank you.

11:06That was Mark Mjadovnik speaking at TED 2025. If you're curious about TED's curation, find out more at ted.com slash curation guidelines. And that's it for today. TED Talks Daily is part of the TED Audio Collective. This talk was fact-checked by the TED Research Team and produced and edited by our team, Martha Estefanos, Oliver Friedman, Brian Green, Lucy Little, and Tonsika Sungmarnivong. This episode was mixed by Christopher Faze Bogan. Additional support from Emma Taubner and Daniela Balarezzo. I'm Elise Hu. I'll be back tomorrow with a fresh idea for your feed. Thanks for listening.