Laboratory of Biomaterials (Labiomat), Materials Departament, Federal University of Rio Grande do Sul, Av. Bento Gonçalves, 9500, 91501-970, Porto Alegre, RS, Brazil.
J Mater Sci Mater Med. 2017 Sep 15;28(10):168. doi: 10.1007/s10856-017-5989-1.
The development of 3D printing hardware, software and materials has enabled the production of bone substitute scaffolds for tissue engineering. Calcium phosphates cements, such as those based on α-tricalcium phosphate (α-TCP), have recognized properties of osteoinductivity, osteoconductivity and resorbability and can be used to 3D print scaffolds to support and induce tissue formation and be replaced by natural bone. At present, however, the mechanical properties found for 3D printed bone scaffolds are only satisfactory for non-load bearing applications. This study varied the post-processing conditions of the 3D powder printing process of α-TCP cement scaffolds by either immersing the parts into binder, Ringer's solution or phosphoric acid, or by sintering in temperatures ranging from 800 to 1500 °C. The porosity, composition (phase changes), morphology, shrinkage and compressive strength were evaluated. The mechanical strength of the post-processed 3D printed scaffolds increased compared to the green parts and was in the range of the trabecular bone. Although the mechanical properties achieved are still low, the high porosity presented by the scaffolds can potentially result in greater bone ingrowth. The phases present in the scaffolds after the post-processing treatments were calcium-deficient hydroxyapatite, brushite, monetite, and unreacted α-TCP. Due to their chemical composition, the 3D printed scaffolds are expected to be resorbable, osteoinductive, and osteoconductive.
3D 打印硬件、软件和材料的发展使得用于组织工程的骨替代支架得以生产。磷酸钙水泥，如基于 α-磷酸三钙 (α-TCP) 的磷酸钙水泥，具有公认的成骨诱导性、骨传导性和可吸收性，可以用于 3D 打印支架以支持和诱导组织形成，并被天然骨替代。然而，目前 3D 打印骨支架的机械性能仅能满足非承重应用的要求。本研究通过将零件浸入粘结剂、林格氏液或磷酸中，或在 800 至 1500°C 的温度下进行烧结，改变了 α-TCP 水泥支架 3D 粉末打印工艺的后处理条件。评估了多孔率、组成（相变化）、形态、收缩和抗压强度。与生坯相比，后处理 3D 打印支架的机械强度增加，并且处于小梁骨的范围内。尽管所达到的机械性能仍然较低，但支架的高多孔性可能导致更大的骨长入。后处理后支架中存在的相是缺钙羟磷灰石、二水合磷酸氢钙、单水磷酸钙和未反应的 α-TCP。由于其化学成分，预计 3D 打印支架可吸收、具有成骨诱导性和骨传导性。
