Design and Mechanical Properties Verification of Gradient Voronoi Scaffold for Bone Tissue Engineering

Haiyuan Zhao; Yafeng Han; Chen Pan; Ding Yang; Haotian Wang; Tingyu Wang; Xinyun Zeng; Penglei Su

doi:10.3390/mi12060664

Design and Mechanical Properties Verification of Gradient Voronoi Scaffold for Bone Tissue Engineering

Micromachines (Basel). 2021 Jun 5;12(6):664. doi: 10.3390/mi12060664.

Authors

Haiyuan Zhao¹, Yafeng Han¹, Chen Pan^{1

2}, Ding Yang¹, Haotian Wang¹, Tingyu Wang^{1

2}, Xinyun Zeng², Penglei Su¹

Affiliations

¹ School of Mechanical Engineering, Beijing Institute of Technology, Zhongguancun South Street No.5, Haidian District, Beijing 100081, China.
² Institute of Engineering Medicine, Beijing Institute of Technology, Zhongguancun South Street No.5, Haidian District, Beijing 100081, China.

Abstract

In order to obtain scaffold that can meet the therapeutic effect, researchers have carried out research on irregular porous structures. However, there are deficiencies in the design method of accurately controlling the apparent elastic modulus of the structure at present. Natural bone has a gradient porous structure. However, there are few studies on the mechanical property advantages of gradient bionic bone scaffold. In this paper, an improved method based on Voronoi-tessellation is proposed. The method can get controllable gradient scaffolds to fit the modulus of natural bone, and accurately control the apparent elastic modulus of porous structure, which is conducive to improving the stress shielding. To verify the designed structure can be fabricated by additive manufacturing, several designed models are obtained by SLM and EBM. Through finite element analysis (FEA), it is verified that the irregular porous structure based on Voronoi-tessellation is more stable than the traditional regular porous structure of the same structure volume, the same pore number and the same material. Furthermore, it is verified that the gradient irregular structure has a better stability than the non-gradient structure. An experiment is conducted successfully to verify the stability performance got by FEA. In addition, a dynamic impact FEA is also performed to simulate impact resistance. The result shows that the impact resistance of the regular porous structure, the irregular porous structure and the gradient irregular porous structure becomes better in turn. The mechanical property verification provides a theoretical basis for the structural design of gradient irregular porous bone tissue engineering scaffolds.

Keywords: Voronoi-tessellation; gradient bionic scaffold; impact resistance verification; irregular porous structure; stability verification; stress shielding.