Proteus from Durham University is a non-cuttable material made of a ceramic spheres within a flexible aluminum structure that interferes with cutting tools.


  • Lightweight
  • Durable
  • Non-cuttable


  • Security
  • Protective equipment
  • Armor

UN Sustainable Development Goals Addressed

  • Goal 9: Industry Innovation & Infrastructure

The Challenge

Protective equipment must be able to endure potential cutting forces which can damage the material and make it vulnerable to breakage. Once a cut penetrates a material, it makes it easier for the material to collapse, as well as letting dust and dirt enter.

Innovation Details

The non-cuttable material, called Proteus, is a lightweight material made of ceramic spheres within a flexible, cellular aluminum structure. The design was inspired by the tough cellular skin of grapefruit and fracture-resistant mollusk shells. When a cutting tool, like an angle grinder, tries to cut into the material, the ceramic spheres blunt the cutting tool, eventually rendering it effective. Additionally, the force generated between the grinder and the spheres creates a vibration that prevents the grinder from sufficiently penetrating. The ceramic spheres also slowly fragment and fill spaces within the material, hardening the material. This process is increased further as the tool speed increases.

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Biological Model

Fruits like the grapefruit and pomelo have excellent damping properties due to the hierarchical organization of their peels. When pomelo fruits fall from the ground, air pockets within the peel collapse like a cushion, absorbing the energy of impact and protecting the peel from damage.

Nacre’s specific composition and construction make it tough and resistant to catastrophic failure that can result from spreading cracks. This means that a greater amount of energy is needed to fracture or break the material. Hard microscale mineral layers in nacre are “glued” together by relatively soft nanoscale organic layers. The arrangement is much like staggered layers of bricks that are held together by mortar in a brick wall.