Relationship between the morphological, mechanical and permeability properties of porous bone scaffolds and the underlying microstructure

PLoS One. 2020 Sep 1;15(9):e0238471. doi: 10.1371/journal.pone.0238471. eCollection 2020.

Abstract

Bone scaffolds are widely used as one of the main bone substitute materials. However, many bone scaffold microstructure topologies exist and it is still unclear which topology to use when designing scaffold for a specific application. The aim of the present study was to reveal the mechanism of the microstructure-driven performance of bone scaffold and thus to provide guideline on scaffold design. Finite element (FE) models of five TPMS (Diamond, Gyroid, Schwarz P, Fischer-Koch S and F-RD) and three traditional (Cube, FD-Cube and Octa) scaffolds were generated. The effective compressive and shear moduli of scaffolds were calculated from the mechanical analysis using the FE unit cell models with the periodic boundary condition. The scaffold permeability was calculated from the computational fluid dynamics (CFD) analysis using the 4×4×4 FE models. It is revealed that the surface-to-volume ratio of the Fischer-Koch S-based scaffold is the highest among the scaffolds investigated. The mechanical analysis revealed that the bending deformation dominated structures (e.g., the Diamond, the Gyroid, the Schwarz P) have higher effective shear moduli. The stretching deformation dominated structures (e.g., the Schwarz P, the Cube) have higher effective compressive moduli. For all the scaffolds, when the same amount of change in scaffold porosity is made, the corresponding change in the scaffold relative shear modulus is larger than that in the relative compressive modulus. The CFD analysis revealed that the structures with the simple and straight pores (e.g., Cube) have higher permeability than the structures with the complex pores (e.g., Fischer-Koch S). The main contribution of the present study is that the relationship between scaffold properties and the underlying microstructure is systematically investigated and thus some guidelines on the design of bone scaffolds are provided, for example, in the scenario where a high surface-to-volume ratio is required, it is suggested to use the Fischer-Koch S based scaffold.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bone Substitutes / pharmacology
  • Bone Transplantation / methods*
  • Bone and Bones / pathology*
  • Compressive Strength
  • Finite Element Analysis
  • Hydrodynamics
  • Materials Testing
  • Permeability
  • Porosity
  • Pressure
  • Stress, Mechanical
  • Tissue Engineering / methods
  • Tissue Scaffolds / chemistry*

Substances

  • Bone Substitutes

Associated data

  • figshare/10.6084/m9.figshare.12721325

Grants and funding

Dr. Yongtao Lu received the funding from the National Natural Science Foundation of China (grant number: 11702057), the Liaoning Provincial Natural Science Foundation of China (grant number: 2019-MS-040) and the DUT-BSU grant (grant number: ICR1903). Dr. Yongtao Lu and Dr. Hanxing Zhu jointly received the funding from the State Key Laboratory of Structural Analysis for Industrial Equipment, Dalian University of Technology (GZ19108). These funding sponsored Dr. Lu and Dr. Zhu’s research activities including study design, data analysis and preparation of the manuscript.