Additive Manufacturing Division, Singapore Institute of Manufacturing Technology (SIMTech), Agency for Science, Technology and Research (A*STAR), 5 Cleantech Loop, 636732 Singapore, Singapore.
Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, 117575 Singapore, Singapore.
Biomater Adv. 2025 Jan;166:214059. doi: 10.1016/j.bioadv.2024.214059. Epub 2024 Oct 9.
Magnesium (Mg) alloys are a promising candidate for synthetic bone tissue substitutes. In bone tissue engineering, achieving a balance between pore characteristics that facilitate biological functions and the essential stiffness required for load-bearing functions is extremely challenging. This study employs binder jet additive manufacturing to fabricate an interconnected porous structure in Mg alloys that mimics the microporosity and mechanical properties of human cortical bone types. Using scanning electron microscopy, micro-computed tomography, and mercury intrusion porosimetry, we found that the binder jet printed and sintered (BJPS) MgZnZr alloys possess an interconnected porous structure, featuring an overall porosity of 13.3 %, a median pore size of 12.7 μm, and pore interconnectivity exceeding 95 %. The BJPS MgZnZr alloy demonstrated a tensile strength of ~130 MPa, a yield strength of ~100 MPa, an elastic modulus of ~21.5 GPa, and an ultimate compressive strength of ~349 MPa. These values align with the ranges observed in human bone types and outperform those of porous Mg alloys produced using the other conventional and additive manufacturing methods. Moreover, the BJPS MgZnZr alloy showed level 0 cytotoxicity with a greater MC3T3-E1 cell viability, attachment, and proliferation when compared to a cast MgZnZr counterpart, since the highly interconnected 3D porous structure provides cells with an additional dimension for infiltration. Finally, we provide evidence for the concept of using binder jet additive manufacturing for fabricating Mg implants tailored for applications in hard tissue engineering, including craniomaxillofacial procedures, bone fixation, and substitutes for bone grafts. The results of this study provide a solid foundation for future advancements in digital manufacturing of Mg alloys for biomedical applications.
镁（Mg）合金是合成骨组织替代物的有前途的候选材料。在骨组织工程中，实现促进生物功能的孔特征与承载功能所需的必要刚度之间的平衡极具挑战性。本研究采用粘结剂喷射增材制造技术在 Mg 合金中制造模仿人皮质骨类型的微孔结构和机械性能的互连多孔结构。使用扫描电子显微镜、微计算机断层扫描和压汞孔隙率法，我们发现粘结剂喷射印刷和烧结（BJPS）MgZnZr 合金具有互连多孔结构，总孔隙率为 13.3%，中值孔径为 12.7μm，孔连通性超过 95%。BJPS MgZnZr 合金的拉伸强度约为 130MPa，屈服强度约为 100MPa，弹性模量约为 21.5GPa，极限抗压强度约为 349MPa。这些值与在人骨类型中观察到的值一致，并优于使用其他常规和增材制造方法生产的多孔 Mg 合金的值。此外，与铸造 MgZnZr 合金相比，BJPS MgZnZr 合金具有 0 级细胞毒性，MC3T3-E1 细胞活力、黏附和增殖更高，因为高度互连的 3D 多孔结构为细胞提供了一个额外的渗透维度。最后，我们提供了使用粘结剂喷射增材制造技术制造用于硬组织工程应用的 Mg 植入物的概念证据，包括颅颌面手术、骨固定和骨移植物替代品。本研究的结果为未来用于生物医学应用的 Mg 合金的数字制造提供了坚实的基础。
