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Auxetic Metamaterial

3D printingAuxetic MetamaterialsbiomaterialsCellular Structure


The invention describes a novel 3D-printed cellular auxetic metamaterial with tunable mechanical properties, which can be used as a bone-substitute biomateterial for custom made titanium ortophedic implants, fabricated using additive manufactuting techniques

Technical features

The invention refers to an innovative, additively manufactured, trabecular auxetic metamaterial in titanium (or eventually using polymers) for custom made bone replacement prostethics in the oncologic field. The elementary cell of the proposed system consists of eight highly porous chiral auxetic elements with a central prismatic shape, possessing a negative Poisson’s ratio (i.e. an auxetic behavior) and tailored mechanical properties, which can be calibrated by the peculiar geometric characteristics of the lattice. The proposed structure is lightweight and instrinsically stiff, showing a negative Poisson’s ratio behavior and an elastic modulus that increase the osteointegration process, while reducing the stress-shielding phenomenon.. Tests on dimostrative prototype (non real dimension and material) assess TRL = 4.

Possible Applications

  • Custom made vertebral prosthetics;
  • Large bone orthopedic implants;
  • Lightweight structures with high energy absorption.


  • To obtain an elastic modulus similar to that of human trabecular bones;
  • Design a highly porous structure;
  • To decrease stress-shielding phenomena;
  • To increase bone ingrowth.