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The Brilliance of Bridges and Roads That Repair Themselves | Mark Miodownik | TED

TED09:53Added Aug 30, 2026

Your skin heals after a scratch. What if our roads, bridges and cities could self-repair after getting damaged, too? Scientist and engineer Mark Miodownik describes a new class of materials — animate matter — with the potential to sense damage, self-heal and even biodegrade when the job is done. Humanity's next great leap isn't making more stuff, he says — it's making stuff that doesn't fall apart. (Recorded at TED2025 on April 10, 2025)

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Contributed by 刘嘉琪

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  1. 00:04If you come and visit me in London, you'll see streetscapes a bit like this.
  2. 00:10And if you see the world through my eyes,
  3. 00:14you'd see this.
  4. 00:16Don't pity me, OK?
  5. 00:19I love this stuff.
  6. 00:21We just make so many amazing materials as humans.
  7. 00:24In fact, that's what we do.
  8. 00:26We have done that for thousands of years.
  9. 00:28We make stuff.
  10. 00:30At first we made tools which allowed us to make clothes.
  11. 00:33And then it allowed us to make shelter
  12. 00:36to protect us from storms and from the weather,
  13. 00:39and containers, which allowed us to store food
  14. 00:41so we could survive the winters.
  15. 00:43And then we started to dream big.
  16. 00:45You know, we started to make boats
  17. 00:48and we started to make materials that cure toothache.
  18. 00:52And we made stuff that could harness electricity,
  19. 00:54we made airplanes,
  20. 00:56and we made stuff that could go to the Moon.
  21. 00:58I mean, this is who we are.
  22. 01:00We make stuff, and here it is.
  23. 01:05Why do we make so much stuff?
  24. 01:08Why?
  25. 01:09Well, it represents who we are.
  26. 01:11This is who humans are.
  27. 01:12We like to make stuff.
  28. 01:14We like to dream big.
  29. 01:15We like to create.
  30. 01:20So that is why civilization gets pushed forward.
  31. 01:23It's why the ages of civilization are named after materials.
  32. 01:25We have the Stone Age. We have the Copper Age.
  33. 01:28We have all the ages until now.
  34. 01:32But there's a problem.
  35. 01:34You're all familiar with an image of a pothole.
  36. 01:37You've all driven straight into a pothole.
  37. 01:39Or, you know, on a bike,
  38. 01:41being thrown off your bike by hitting one of these potholes.
  39. 01:44They're a menace.
  40. 01:47If you're on an e-scooter, you just disappear right down them.
  41. 01:50(Laughter)
  42. 01:53All of our stuff, we've got so good at making it,
  43. 01:55but we're not so good at repairing it.
  44. 01:57We're not so good at taking care of it.
  45. 02:00And that is our next big task.
  46. 02:02Our next adventure, as humans.
  47. 02:06I think.
  48. 02:07So what would a future like that look like?
  49. 02:10Imagine a city now of the future.
  50. 02:12But imagine one that doesn't constantly fall apart,
  51. 02:15that doesn't constantly have potholes and cracks in bridges,
  52. 02:18that when a storm hits
  53. 02:20and a small, it’s damaged,
  54. 02:22then it heals itself.
  55. 02:25What would that be like?
  56. 02:26Could we do it?
  57. 02:28Can we make bridges, tunnels, roads, buildings
  58. 02:31that repair themselves?
  59. 02:34The answer is some stuff called “animate matter.”
  60. 02:40And what is animate matter?
  61. 02:41Well animate matter is a different form of material.
  62. 02:44We're borrowing from nature.
  63. 02:46It's a form of material that repairs itself, heals itself,
  64. 02:50actuates, senses the environment.
  65. 02:54Is it impossible to make?
  66. 02:55No. We're making it now.
  67. 02:58People in my lab.
  68. 02:59Hundreds of people in labs all over the world
  69. 03:02are making this stuff called animate matter.
  70. 03:05But to tell you how it works, I first need to take you inside materials.
  71. 03:10I need to show you how they work.
  72. 03:12And this map of the world is perhaps unfamiliar to you, right?
  73. 03:17So this is how we material scientists understand the material world,
  74. 03:21it's how we design new materials.
  75. 03:23You've got big stuff at the top,
  76. 03:24and you get smaller, smaller, smaller, smaller, smaller.
  77. 03:27So on the left-hand side you can see the natural world,
  78. 03:30how nature builds materials.
  79. 03:31You have trees, and then you have whales,
  80. 03:33and you have mice, and then you have the fleas on the mice,
  81. 03:36and the hairs on the fleas.
  82. 03:38And inside those you have tissues.
  83. 03:40And there are many types of tissues.
  84. 03:42We have skin tissue, lips, we have brain tissue.
  85. 03:45Then you zoom in further, you get single cells.
  86. 03:48And then you zoom in further
  87. 03:49and you get the whole molecular machinery of cells.
  88. 03:52And you zoom in further and you get the DNA.
  89. 03:54And it's the DNA that builds those machines,
  90. 03:56and the machines that build the cells, and cells build the tissues.
  91. 04:00And so you get the idea.
  92. 04:01The way nature builds materials is that it stacks every layer on another,
  93. 04:06that they are all grown inside each other.
  94. 04:09Big stuff contains small stuff.
  95. 04:11We are multiscale materials.
  96. 04:15And what is life then? What is it to be alive?
  97. 04:17Well, it's the connection between those scales.
  98. 04:21The scales themselves are physics and chemistry.
  99. 04:23But the stuff that connects them, the information,
  100. 04:27they check each other, they repair each other.
  101. 04:29If they find some damage,
  102. 04:32they repair that.
  103. 04:33And you're doing it now, right? You are repairing yourself now.
  104. 04:37You get a scratch, your body just goes to work repairing it.
  105. 04:41So nature builds materials, but it builds self-repaired materials.
  106. 04:45Now we have built materials too, we built amazing tools,
  107. 04:48massive bridges, cars, phones.
  108. 04:50We've mastered these different scales.
  109. 04:52We can zoom in, we can make nanostructures,
  110. 04:55we can manipulate atoms, we can make transistors.
  111. 04:57And what we really lack is the ability to connect those scales up
  112. 05:01and to get them to self-repair.
  113. 05:03And that is the big next challenge.
  114. 05:06Can we do it?
  115. 05:07Well look, let me take you through some work that we’re doing,
  116. 05:10that we're already making great progress.
  117. 05:12So self-repairing roads.
  118. 05:13When we analyze the roads,
  119. 05:14we realize that big potholes start off as tiny microscopic cracks.
  120. 05:19And the key to stopping them doing runaway growth into a pothole
  121. 05:22is to catch them early.
  122. 05:24If you zoom in now and we started to look at the different structures inside roads,
  123. 05:29what we found are maltenes and micelles.
  124. 05:31And actually, they can self-repair.
  125. 05:33They actually can move around.
  126. 05:35But you need to give them impetus. You need to give them energy.
  127. 05:38So we put embedded nanoparticles into that material,
  128. 05:42and by actuating with magnetic field,
  129. 05:44we can get them to move around
  130. 05:46and self-repair the microcracks before they become potholes.
  131. 05:50Another example -- self-repairing concrete.
  132. 05:53There are people in the world
  133. 05:54who've been making this for quite a while now.
  134. 05:56You can buy this stuff.
  135. 05:58How does it work?
  136. 05:59Well, inside the concrete
  137. 06:01are tiny microorganisms placed there by the concrete manufacturers.
  138. 06:05When a big storm hits and a crack opens up,
  139. 06:08the microbacteria wake up.
  140. 06:11They smell the humid air. They look around for food.
  141. 06:13They find starch that's been left there by the designers of the concrete.
  142. 06:17They eat it, they do a poo, and they poo calcite. Yes.
  143. 06:21(Laughter)
  144. 06:22They eat their way out of the crack, leaving pristine material behind them
  145. 06:26and restoring the concrete to 90 percent of its original strength.
  146. 06:30It works today.
  147. 06:32Self-disassembling plastic.
  148. 06:33So we've been working on this problem
  149. 06:35that you need to put plastic wrappers around small seedlings to grow trees
  150. 06:40to reforest the world.
  151. 06:41But the problem is the plastic itself then pollutes the world.
  152. 06:44So can we get a material that protects the tree for years on end,
  153. 06:50but when that tree is mature
  154. 06:52will then disintegrate and become biodegradable.
  155. 06:55Answer -- yes.
  156. 06:56We're embedding little tiny enzymes
  157. 06:59that catalyze the disassembly of those polymers, of those plastics,
  158. 07:03and we get them into the plastic
  159. 07:05by wrapping them in a random heteropolymer.
  160. 07:08And that allows them to survive the high-temperature process
  161. 07:10of making the plastic
  162. 07:12and to survive in the environment until they're needed.
  163. 07:14And then they come out and it disintegrates.
  164. 07:17And we're still testing this now.
  165. 07:19So these animate materials I'm talking about,
  166. 07:22they are really extraordinary.
  167. 07:24And they are possible now. We are making them.
  168. 07:27And they make self-repairing roads, self-repairing bridges
  169. 07:31and self, you know, self-biodegradable materials
  170. 07:35much more tangible in the future.
  171. 07:38So ...
  172. 07:40what are the problems we face?
  173. 07:42It's not so much the technical stuff. We can do the technical stuff.
  174. 07:45Probably one of the biggest hurdles is the economics.
  175. 07:48At the moment we have a system where we make stuff, it falls apart,
  176. 07:51we remake it, it falls apart,
  177. 07:53and we throw the waste away into the environment.
  178. 07:55We do this with roads, we do this with buildings,
  179. 07:58we do this with electronics, we do this with clothes,
  180. 08:00we do this with pretty much everything.
  181. 08:02And we're basically just piling our materials, our wonderful materials,
  182. 08:05the ones that we've made over time immemorial,
  183. 08:08we just throw them away as if we don't care.
  184. 08:10And we've got to stop.
  185. 08:12We've got to take care of our materials.
  186. 08:14But we need a new economic model.
  187. 08:16The consumerist model doesn't work for a sustainable future,
  188. 08:19for a non-polluting future.
  189. 08:21And I think animate materials will play a really big part
  190. 08:26in making this future.
  191. 08:27And when you calculate the cost of that pollution and that global warming,
  192. 08:32then they'll start to make sense economically.
  193. 08:35So what would it feel like, though, to live in this world,
  194. 08:40to live in a world that is animate?
  195. 08:43Well, I think in 20 years’ time, you come to visit me in London
  196. 08:46and the animate materials are now in the infrastructure
  197. 08:49and in our phones, and in our laptops,
  198. 08:53I don't think it will feel weird.
  199. 08:55I think it will feel a bit like being in a forest.
  200. 08:59Right? You go into a forest, all of that stuff is looking after itself,
  201. 09:03repairing itself, building itself.
  202. 09:05In fact, we could push these animate materials to make themselves.
  203. 09:11Perhaps we could make roads that build themselves.
  204. 09:14And then what would our job be?
  205. 09:16Our job wouldn’t be constantly have to repair things,
  206. 09:19laboriously throw things away,
  207. 09:21remake them.
  208. 09:22Our jobs would be more like gardeners.
  209. 09:24Right? Yeah. The city would look after itself.
  210. 09:27We could enjoy ourselves,
  211. 09:28occasionally pruning a road that was drifting off into the wilderness.
  212. 09:32Yeah?
  213. 09:33Or it had rebuilt a bedroom of yours,
  214. 09:35and you didn't quite like the design,
  215. 09:37and you could push back on it a bit.
  216. 09:39But that is the world we're heading towards.
  217. 09:42That's the future.
  218. 09:44A future where we take care of our stuff.
  219. 09:48Thank you.
  220. 09:49(Applause)