QBone

Biological tissues have mechanical and functional properties that are extremely difficult to replicate. They are intrinsically multi-scaled, hierarchical, architectured and heterogeneous materials, and their exceptional features are the result of a smart arrangement of the basic constituents of the tissue at different scales. When these tissues need to be replaced or repaired, for instance in the case of bone defects after a trauma, the common practice is to achieve a sufficiently high factor of safety by using constituent materials that are much stiffer than the ones used in nature, like titanium. This leads to undesired effect such as an uneven load distribution that may eventually conduct to bone loss. It has been shown that using porous (and less stiff) implants reduces this problem. Generally, porous bone substitutes fall into two categories: (1) random materials such as foams and (2) periodic materials such as lattices. Interestingly, quasiperiodic order, a generalization of periodicity emerging from the study of quasicrystals, allows combining the advantages of both categories, while maintaining a well-defined, deterministic architecture. Indeed, the local disorder induces good toughness (superior to that of a periodic structure), while allowing phonon diffraction and thus the presence of full band gaps as an appealing acoustic signature. The main objectives of QBone are: to develop a methodological framework to model and optimise the design of quasiperiodic architectured bone scaffolds; to optimise the acoustic signature of bone scaffolds allowing for a better characterisation and monitoring; and to assess the osseointegration capabilities of such optimised architectured scaffoldswith in-vivo tests. The breakthrough of the project lies in the added value it offers over classic destructive testing, enabling repeated assessments and long-term analysis while preserving the structural integrity of the implants.