Chinese Journal of Tissue Engineering Research ›› 2024, Vol. 28 ›› Issue (5): 741-746.doi: 10.12307/2024.253

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Structural design and mechanical property analysis of trabecular scaffold of triply periodic minimal surface with a radial gradient

Zhang Yihai1, Shang Peng1, Ma Benyuan1, Hou Guanghui1, Cui Lunxu1, Song Wanzhen1, Qi Dexuan1, Liu Yancheng2   

  1. 1School of Mechanical Engineering, Hebei University of Technology, Tianjin 300401, China; 2Tianjin Hospital, Tianjin University, Tianjin 300211, China
  • Received:2022-12-26 Accepted:2023-03-06 Online:2024-02-18 Published:2023-08-16
  • Contact: Shang Peng, MD, Associate professor, Master’s supervisor, School of Mechanical Engineering, Hebei University of Technology, Tianjin 300401, China Liu Yancheng, MD, Associate chief physician, Tianjin Hospital, Tianjin University, Tianjin 300211, China
  • About author:Zhang Yihai, Master candidate, School of Mechanical Engineering, Hebei University of Technology, Tianjin 300401, China Shang Peng, MD, Associate professor, School of Mechanical Engineering, Hebei University of Technology, Tianjin 300401, China
  • Supported by:
    General Program of Hebei Natural Science Foundation, No. E2022202164 (to SP); Key Research Project of Hebei Provincial Department of Education, No. ZD2020124 (to SP); Wu Jieping Medical Foundation Project, No. 320.6750.2022-18-49 (to LYC); Beijing Medical and Health Public Welfare Foundation Project, No. B20371FN (to LYC)

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Abstract: BACKGROUND: The elastic modulus of traditional bone implants is large and does not match the elastic modulus of human bone, which will cause a stress shielding effect and lead to bone resorption. The trabecular scaffold of the triply periodic minimal surface with radial gradient has elastic modulus matching with human cancellous bone, and its yield strength is greater than that of human cortical bone, which provides a new choice for the design of bone scaffold. 
OBJECTIVE: Triply periodic minimal surface structure with radial gradient was constructed by the implicit surface method. The sample was manufactured by laser selective melting technology, and the quasi-static compression test was carried out to obtain trabecular scaffolds with mechanical properties matching human bones.
METHODS: Four types of the trabecular scaffolds of the triply periodic minimal surface with a radial gradient of G, I, P and D were established by the implicit surface method. Samples were manufactured by laser selective melting technology. We observed the surface morphology of the molded sample, evaluated the molding quality, conducted a quasi-static compression test, and evaluated the mechanical properties of the samples.
RESULTS AND CONCLUSION: The quasi-static compression test results showed that compared with the four triply periodic minimal surface scaffolds, the platform stress of the G scaffold had less fluctuation and no failure or fracture, indicating that the G scaffold had the best plasticity. The mechanical properties of the G scaffolds with 45%, 55% and 65% porosities were analyzed. It was found that the elastic modulus of G scaffolds with 55% porosity was within the range of elastic modulus of human cancellous bone (0.022-3.7 GPa), and the yield strength was close to the maximum yield strength of human cortical bone (187.7-222.3 MPa). In conclusion, G triply periodic minimal surface scaffold with 55% porosity can reduce the stress shielding effect, bear a higher body load, improve the stability of the implant, and prolong the service life of the implant.

Key words: laser selective melting, triply periodic minimal surface, radial gradient, trabecular scaffold, mechanical property

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