Simultaneous optimization of stiffness, permeability, and surface area in metallic bone scaffolds

Abstract

Metallic bone scaffolds fabricated by selective laser melting (SLM) have attracted significant attention in bone tissue engineering. Scaffolds based on triply periodic minimal surfaces (TPMS) are currently the subject of extensive investigation, making them a fitting benchmark for evaluating novel architectures. In this study, we introduced and assessed the viability of modified face-centered cubic (MFCC) scaffolds as an alternative to TPMS scaffolds. Two distinct categories of TPMS scaffolds, namely sheet TPMS and skeletal TPMS, were examined for comparative analysis. Employing finite element method (FEM) and computational fluid dynamics (CFD) analysis, we comprehensively evaluate the MFCC and TPMS scaffolds from structure, fluid flow, surface area, and surface curvature perspectives. Among the investigated porosities (75%, 80% and 85%), the MFCC scaffold category consistently exhibited dominant designs on the Pareto front, whereas the majority of TPMS scaffolds failed to achieve multiobjective optimality. MFCC scaffolds exhibited superior mechanical properties compared to skeletal TPMS scaffolds, while also demonstrating improved fluid flow characteristics in contrast to sheet TPMS scaffolds. Furthermore, MFCC scaffolds possessed a specific surface area that fell within the range observed in natural bone tissue, thereby bridging a crucial gap in the design space for optimizing bone scaffolds. The concave internal surfaces of MFCC scaffolds showed promising potential for enhancing bone cell growth. Selective laser melting (SLM) was employed to fabricate the designed scaffolds using stainless steel 316L. Subsequently, uniaxial compression tests were conducted on these scaffolds to validate the accuracy of the simulation results. This study provides valuable insights into multiobjective design and optimization of bone scaffolds, highlighting the significance of MFCC scaffolds as a valuable addition to the existing library of bone scaffold architectures.