用于小梁骨组织替代的具有可控孔隙率的3D打印聚乳酸支架的形态学和力学特性

Morphological and mechanical characterization of 3D printed PLA scaffolds with controlled porosity for trabecular bone tissue replacement.

作者信息

Baptista R, Guedes M

机构信息

CDP2T, Departamento de Engenharia Mecânica, Escola Superior de Tecnologia de Setúbal, Instituto Politécnico de Setúbal, 2910-761 Setúbal, Portugal; IDMEC, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.

CDP2T, Departamento de Engenharia Mecânica, Escola Superior de Tecnologia de Setúbal, Instituto Politécnico de Setúbal, 2910-761 Setúbal, Portugal; CeFEMA, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal.

出版信息

Mater Sci Eng C Mater Biol Appl. 2021 Jan;118:111528. doi: 10.1016/j.msec.2020.111528. Epub 2020 Sep 18.

Abstract

Bone transplant is still the gold standard approach when dealing with orthopedic trauma or disease. When this solution is not possible, scaffolding is a possibility provided by bone tissue engineering. To support the regeneration process, damaged bone tissue is removed and replaced by porous scaffold structures. In recent years, additive manufacturing has shown huge potential to produce scaffold structures with the required performance. In the current work, PLA scaffolds with different designs were 3D printed, using optimal manufacturing parameters. Scaffolds with three different porosity values were obtained by changing the filament offset from 571 to 1333 μm. A total of twelve designs were tested under monotonic and dynamic compression conditions. Numerical analysis showed good correlation with experimental results, allowing for a better assessment of scaffold mechanical behavior. Stress relaxation was measured on four different strain levels, assessing scaffold's behavior after implantation and consequent static response over time. Overall, orthogonal design provided better performance, due to improved material deposition. With lower porosity scaffolds equilibrium stress reached 24 MPa after 300 s relaxation time under 4% deformation, and the obtained equilibrium modulus was 428 MPa. Overall, attained results show that 3D printing with PLA can be applied in the manufacture of scaffolds for trabecular bone replacement.

摘要

在处理骨科创伤或疾病时,骨移植仍是金标准方法。当这种解决方案不可行时,骨组织工程提供了一种可能性,即使用支架。为了支持再生过程,受损的骨组织被去除,并用多孔支架结构替代。近年来,增材制造在生产具有所需性能的支架结构方面显示出巨大潜力。在当前工作中,使用最佳制造参数对具有不同设计的聚乳酸(PLA)支架进行了3D打印。通过将长丝偏移从571微米改变到1333微米,获得了具有三种不同孔隙率值的支架。总共十二个设计在单调和动态压缩条件下进行了测试。数值分析表明与实验结果具有良好的相关性,从而能够更好地评估支架的力学行为。在四个不同应变水平上测量了应力松弛,评估了支架植入后的行为以及随时间的静态响应。总体而言,由于材料沉积得到改善,正交设计提供了更好的性能。对于孔隙率较低的支架,在4%变形下经过300秒的松弛时间后,平衡应力达到24兆帕,获得的平衡模量为428兆帕。总体而言,所得结果表明,使用聚乳酸进行3D打印可应用于制造用于替代松质骨的支架。

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