A new ultra-strong material has been developed that is resistant to power tools and was inspired by a grapefruit and a seashell.

Stefan Szyniszewski, of Durham University, told how he had researched the way soft building blocks can make a hard surface – and this can be extremely useful, for example, in bike locks or home security to prevent break-ins.

In a collaboration between scientists in the UK and Germany, the researchers took inspiration from grapefruit skins and abalone shells to design a lightweight, yet robust material.

"So far, we have not been able to cut it with conventional tools like angle grinders and power drills or water jets. So in that sense, it is not cuttable," said Szyniszewski. 

"And these properties are very important for security applications, for protection from forcible entry, for bike locks, for protective gear, maybe for factory workers, for shoulder pads, so they don't get injured with an angle grinder in the factory."

Szyniszewski used the analogy of a bullet traveling at 700 meters per second being stopped by a sandbag. Yet, a blunt instrument like a pen can open it up, as he described how the new material finds its strength.

The material is named after the shape-changing mythical god Proteus and is made of ceramic spheres within a cellular metallic structure. When power tools try to cut through it, the vibrations cause the material to become even more robust.

The abalone sea creature, with its sturdy shell, inspired Szyniszewski as he saw how soft building blocks could make an "uncuttable" surface.

"You have these soft bricks. That's all you have. And now there is a shark and other predators that want to eat you. So nature has to come out with some defense mechanism for these weak ingredients. Otherwise, it won't survive."

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