Meta-biomaterials with minimal surface morphology

Abstract

Triply Periodic Minimal Surfaces (TPMS) have earned great popularity in porous meta- biomaterials by cause of unique mass transfer properties, tunable mechanical properties, large pore space and high surface to volume ratio. Numerical and experimental studies suggest a great potential for TPMS-based architectures in the treatment of segmental bone defects, where supporting scaffolds are crucial in bridging the gap unable to heal naturally. However, current studies are limited to investigating the properties of classic TPMS archi- tectures. In this thesis, I present the design, fabrication and characterisation of a novel type of meta-biomaterials inspired by TPMS morphology. I show a practical application of Weierstrass equations to define Schwarz P, Schwarz D and Gyroid surfaces, which pro- vides an opportunity to remove fundamental patches from the original surface and design unique structures. Moreover, one of the developed designs applied basics of graph theory to construct the material which mimics the randomness of the trabecular bone structure, while preserving the benefits of regular TPMS morphology. The results demonstrate the improved performance of the modified TPMS scaffolds compared to classic structures in terms of permeability and compliance properties, crucial for the materials applied in or- thopaedic implants. The porosity and permeability values of the developed metamaterial were found to be in the range of trabecular bone. Additionally, the possibilities to simulate the mass transfer properties of the novel material were examined in COMSOL and valu- able qualitative results, like fluid velocity distribution and flow-induced wall shear stress, retrieved. Overall my thesis introduces an innovative idea for biomaterial design and adds a strong argument in favour of TPMS morphology application in the orthopaedic material research field.