Proteus: Scientists create first ever non-cuttable manufactured material, inspired by grapefruits and shells

New material said to act more like living structure than inanimate object

Footage shows an angle grinder attack on the Proteus material (SWNS/Dr Rene Vogel)

Engineers are hailing the creation of the first ever manufactured material which cannot be cut, inspired by the natural defence mechanisms of shells, grapefruit skins, and fish scales capable of resisting piranha attacks.

The lightweight material was able to indefinitely resist any cutting or drilling tools used in tests, blunting them by using their own power against them, the developers said in a paper published in the journal Scientific Reports.

The new creation – named Proteus after the shape-changing Greek water god – acts more like a living structure than an inanimate object, they suggested.

Comparable to diamonds, but far cheaper, it is hoped that Proteus could be used to make bike locks, security doors, lightweight armour and protective equipment for those who work with cutting tools.

“We were intrigued by how the cellular structure of the grapefruit and the tiled structure of mollusc shells can prevent damage to the fruit or the creatures inside, despite being made of relatively weak organic building blocks," said lead author Dr Stefan Szyniszewski, of Durham University, which co-led the research with the Fraunhofer Insitute in Chemnitz.

“These natural structures informed the working principle of our metallic-ceramic material, which is based on dynamic interaction with the applied load, in contrast to passive resistance."

Comprised of ceramic spheres encased in a cellular aluminium structure, which is intended to echo the cellular structures found in nature, the new material essentially has two lines of defence.

The first occurs sees the spheres vibrate upon contact with an external force, which turns the power of a drill or cutting agent back upon itself, destroying or blunting it.

In addition, the power of the drill causes the ceramics to fragment and harden, making Proteus even more resistant and further eroding the blade or drill.

While it took 45 seconds for the team to cut through steel armour used to protect against explosives with an angle grinder, Proteus rendered the same tool useless, The New Scientist reported.

“Essentially cutting our material is like cutting through a jelly filled with nuggets. If you get through the jelly you hit the nuggets and the material will vibrate in such a way that it destroys the cutting disc or drill bit," added Dr Szyniszewski, an assistant professor of applied mechanics.

“The ceramics embedded in this flexible material are also made of very fine particles which stiffen and resist the angle grinder or drill when you’re cutting at speed in the same way that a sandbag would resist and stop a bullet at high speed.

“This material could have lots of useful and exciting applications in the security and safety industries. In fact, we are not aware of any other manufactured non-cuttable material in existence as of now.”

Co-author Dr Miranda Anderson of the University of Stirling added: “Because the successful resistance of our material system requires it to undergo internal transformations, we chose the name Proteus.

“In 1605, Francis Bacon compared natural materials to Proteus who ‘ever changed shapes’ and he argued that through experimentation we can reveal the metamorphic qualities of materials.”

Dr Szyniszewski added: “This is what we’ve achieved with this new material and we’re excited by its potential.”

The study was funded by the Home Office, the UK's Engineering and Physical Sciences Research Council, and the European Commission.

The researchers have a patent pending, and hope to work with industry partners to develop products for the marketplace.