A skin-like plastic that "bleeds" when cut or scratched and then heals has been developed by scientists.
The material could provide self-healing surfaces for a multitude of products ranging from mobile phones and laptops to cars, say researchers.
When cut, the plastic turns from clear to red along the line of the damage, mimicking what happens to skin.
It reacts to ordinary light, or changes in temperature or acidity, by mending broken molecular "bridges" to heal itself.
US scientists told how they created the material at the American Chemical Society's annual meeting in San Diego, California.
Lead researcher Professor Marek Urban, from the University of Southern Mississippi, said: "Mother Nature has endowed all kinds of biological systems with the ability to repair themselves.
"Some we can see, like the skin healing and new bark forming in cuts on a tree trunk. Some are invisible, but help keep us alive and healthy, like the self-repair system that DNA uses to fix genetic damage to genes.
"Our new plastic tries to mimic nature, issuing a red signal when damaged and then renewing itself when exposed to visible light, temperature or pH changes."
The material could flag up damage to critical aircraft structures, said Prof Urban. A decision could then be taken whether to replace the component or "heal" it with a burst of intense light.
Scratches on vehicle fenders could be repaired the same way. Prof Urban's team is now working on incorporating the technology into plastics that can withstand high temperatures.