Lietaert Karel, Zadpoor Amir A, Sonnaert Maarten, Schrooten Jan, Weber Ludger, Mortensen Andreas, Vleugels Jozef
3D Systems, Grauwmeer 14, Leuven 3001, Belgium; Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, Heverlee 3001, Belgium.
Department of Biomechanical Engineering, Delft University of Technology (TU Delft), Mekelweg 2, 2628 CD, Delft, the Netherlands.
Acta Biomater. 2020 Jul 1;110:289-302. doi: 10.1016/j.actbio.2020.04.006. Epub 2020 Apr 27.
In this work, the macrotexture of dense Zn produced by laser powder bed fusion (LPBF) was studied and the mechanical properties for different tensile bar orientations were measured. The compressive strength of LPBF Zn scaffolds with five different unit cells was measured for a relative density of 20-51%. In addition, the response of mesenchymal stem cells to the LPBF Zn scaffolds was studied. The elastic modulus and yield strength of dense LPBF Zn were 110.0 ± 0.2 GPa and 78.0 ± 0.4 MPa, respectively in the vertical and 81.0 ± 0.4 GPa and 55.0 ± 0.7 MPa in the horizontal direction. This could be explained by the preferential orientation of the 〈0001〉 direction in the building plane. For LPBF Zn scaffolds, the plateau stress for the different unit cells varied between 8 and 33 MPa for a 30% relative density. Calcein staining, lactate production and DNA measurements over a 13-day period showed that mesenchymal stem cell viability was low for Zn scaffolds. This work forms a basis for further research into the LPBF texture formation of metals with hexagonal crystal structure, guides implant designers in scaffold unit cell and relative density selection and motivates further research into the cytocompatibility of LPBF Zn. STATEMENT OF SIGNIFICANCE: Laser powder bed fusion (LPBF) is a manufacturing technology which allows the seamless combination of porous and non-porous volumes in a metallic implant and is used in the orthopedic manufacturing industry today. The production of highly dense Zn with LPBF has been described earlier, but the mechanical properties of the resulting material have not been studied in detail yet. This study is the first to report on (i) the influence of different scanning strategies on the macrotexture of dense LPBF Zn and the resulting anisotropy of its mechanical properties, (ii) the relationship between the relative density and strength for LPBF Zn scaffolds with five different unit cells and (iii) the in vitro response of mesenchymal stem cells to these scaffolds.
在这项工作中，研究了激光粉末床熔融（LPBF）制备的致密锌的宏观织构，并测量了不同拉伸棒取向的力学性能。测量了具有五种不同单胞的LPBF锌支架在相对密度为20%至51%时的抗压强度。此外，还研究了间充质干细胞对LPBF锌支架的反应。致密LPBF锌在垂直方向的弹性模量和屈服强度分别为110.0±0.2 GPa和78.0±0.4 MPa，在水平方向为81.0±0.4 GPa和55.0±0.7 MPa。这可以通过〈0001〉方向在构建平面中的择优取向来解释。对于LPBF锌支架，在相对密度为30%时，不同单胞的平台应力在8至33 MPa之间变化。钙黄绿素染色、乳酸生成和13天内的DNA测量表明，锌支架中间充质干细胞的活力较低。这项工作为进一步研究具有六方晶体结构的金属的LPBF织构形成奠定了基础，指导植入物设计者进行支架单胞和相对密度的选择，并推动对LPBF锌的细胞相容性的进一步研究。重要意义声明：激光粉末床熔融（LPBF）是一种制造技术，它允许在金属植入物中无缝结合多孔和无孔体积，并且如今在骨科制造行业中得到应用。此前已经描述了用LPBF制备高密度锌的方法，但所得材料的力学性能尚未详细研究。本研究首次报道了（i）不同扫描策略对致密LPBF锌宏观织构及其力学性能各向异性的影响，（ii）具有五种不同单胞的LPBF锌支架的相对密度与强度之间的关系，以及（iii）间充质干细胞对这些支架的体外反应。
