Faculty of Materials Science and Engineering, Warsaw University of Technology, 141 Woloska Str., 02-507 Warsaw, Poland; Materialscare LTD, Zwierzyniecka 10/1, 15-333 Bialystok, Poland.
Faculty of Materials Science and Engineering, Warsaw University of Technology, 141 Woloska Str., 02-507 Warsaw, Poland.
Mater Sci Eng C Mater Biol Appl. 2019 Feb 1;95:428-439. doi: 10.1016/j.msec.2018.04.019. Epub 2018 Apr 12.
Selective Laser Melting (SLM) is a powder-bed-based additive manufacturing method, using a laser beam, which can be used to produce metallic scaffolds for bone regeneration. However, this process also has a few disadvantages. One of its drawbacks is the necessity of post-processing in order to improve the surface finish. Another drawback lies in the removal of unmelted powder particles from the build. In this study, the influence of chemical polishing of SLM fabricated titanium scaffolds on their mechanical strength and in vitro cellular response was investigated. Scaffolds with bimodal pore size (200 μm core and 500 μm shell) were fabricated by SLM from commercially pure titanium powder and then chemically treated in HF/HNO solutions to remove unmelted powder particles. The cell viability and mechanical strength were compared between as-made and chemically-treated scaffolds. The chemical treatment was successful in the removal of unmelted powder particles from the titanium scaffold. The Young's modulus of the fabricated cellular structures was of 42.7 and 13.3 GPa for as-made and chemically-treated scaffolds respectively. These values are very similar to the Young's modulus of living human bone. Chemical treatment did not affect negatively cell proliferation and differentiation. Additionally, the chemically-treated scaffolds had a twofold increase in colonization of osteoblast cells migrating out of multicellular spheroids. Furthermore, X-ray computed microtomography confirmed that chemically-treated scaffolds met the dimensions originally set in the CAD models. Therefore, chemical-treatment can be used as a tool to cancel the discrepancies between the designed and fabricated objects, thus enabling fabrication of finer structures with regular struts and high resolution.
选择性激光熔化 (SLM) 是一种基于粉末床的增材制造方法，使用激光束，可以用于生产用于骨再生的金属支架。然而，该工艺也有一些缺点。其缺点之一是为了提高表面光洁度需要进行后处理。另一个缺点在于从构建体中去除未熔化的粉末颗粒。在这项研究中，研究了 SLM 制造的钛支架的化学抛光对其机械强度和体外细胞反应的影响。使用 SLM 从商用纯钛粉末制造出具有双峰孔径（200 µm 芯和 500 µm 壳）的支架，然后用 HF/HNO 溶液进行化学处理，以去除未熔化的粉末颗粒。比较了原始制造和化学处理支架之间的细胞活力和机械强度。化学处理成功地从钛支架上去除了未熔化的粉末颗粒。制造的多孔结构的杨氏模量分别为 42.7 和 13.3 GPa。这些值非常接近活人的骨骼的杨氏模量。化学处理不会对细胞增殖和分化产生负面影响。此外，化学处理的支架上多细胞球体迁移出的成骨细胞的定植增加了两倍。此外，X 射线计算机微断层扫描证实，化学处理的支架符合最初在 CAD 模型中设定的尺寸。因此，化学处理可以用作消除设计和制造物体之间差异的工具，从而能够制造具有规则支柱和高分辨率的更精细结构。
