3D printing customised stiffness-matched meta-biomaterial with near-zero auxeticity for load-bearing tissue repair

The evolution of meta-biomaterials has opened up exciting new opportunities for mass personalisation of biomedical devices. This research paper details the development of a CoCrMo meta-biomaterial structure that facilitates personalised stiffness-matching while also exhibiting near-zero auxeticity. Using laser powder bed fusion, the porous architecture of the meta-biomaterial was characterised, showing potential for near-zero Poisson's ratio. The study also introduces a novel surrogate model that can predict the porosity ($\phi$), yield strength (${\sigma }_y$), elastic modulus ($E$), and negative Poisson's ratio ($-\upsilon$) of the meta-biomaterial, which was achieved through prototype testing and numerical modelling. The model was then used to inform a multi-criteria desirability objective, revealing an optimum near-zero $-\upsilon$ of −0.037, with a targeted stiffness of 17.21 GPa. Parametric analysis of the meta-biomaterial showed that it exhibited $-\upsilon$, $\phi$, ${\sigma }_y$ and $E$ values ranging from −0.02 to −0.08, 73.63–81.38%, 41–64 MPa, and 9.46–20.6 GPa, respectively. In this study, a surrogate model was developed for the purpose of generating personalised scenarios for the production of bone scaffolds. By utilising this model, it was possible to achieve near-zero $-\upsilon$ and targeted stiffness personalisation. This breakthrough has significant implications for the field of bone tissue engineering and could pave the way for improved patient outcomes. The presented methodology is a powerful tool for the development of biomaterials and biomedical devices that can be 3D printed on demand for load-bearing tissue reconstruction. It has the potential to facilitate the creation of highly tailored and effective treatments for various conditions and injuries, ultimately enhancing patient outcomes.