Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario, Canada.
J Biomed Mater Res B Appl Biomater. 2010 May;93(2):510-9. doi: 10.1002/jbm.b.31610.
Solid freeform fabrication (SFF) enables the fabrication of anatomically shaped porous components required for formation of tissue engineered implants. This article reports on the characterization of a three-dimensional-printing method, as a powder-based SFF technique, to create reproducible porous structures composed of calcium polyphosphate (CPP). CPP powder of 75-150 microm was mixed with 10 wt % polyvinyl alcohol (PVA) polymeric binder, and used in the SFF machine with appropriate settings for powder mesh size. The PVA binder was eliminated during the annealing procedure used to sinter the CPP particles. The porous SFF fabricated components were characterized using scanning electron microscopy, micro-CT scanning, X-ray diffraction, and mercury intrusion porosimetry. In addition, mechanical testing was conducted to determine the compressive strength of the CPP cylinders. The 35 vol % porous structures displayed compressive strength on average of 33.86 MPa, a value 57% higher than CPP of equivalent volume percent porosity made through conventional gravity sintering. Dimensional deviation and shrinkage analysis was conducted to identify anisotropic factors required for dimensional compensation during SFF sample formation and subsequent sintering. Cell culture studies showed that the substrate supported cartilage formation in vitro, which was integrated with the top surface of the porous CPP similar to that observed when chondrocytes were grown on CPP formed by conventional gravity sintering methods as determined histologically and biochemically.
立体光固化成型（SFF）能够制造出用于组织工程植入物形成的具有解剖形状的多孔部件。本文报道了一种三维打印方法的特性，该方法是一种基于粉末的 SFF 技术，可创建由磷酸钙多聚体（CPP）组成的可重复的多孔结构。75-150 微米的 CPP 粉末与 10wt%的聚乙烯醇（PVA）聚合物粘合剂混合，并在 SFF 机器中使用适当的粉末网格尺寸设置。在用于烧结 CPP 颗粒的退火过程中，消除了 PVA 粘合剂。使用扫描电子显微镜、微 CT 扫描、X 射线衍射和压汞孔隙率测试对 SFF 制造的多孔部件进行了表征。此外，还进行了机械测试以确定 CPP 圆柱的抗压强度。35vol%的多孔结构的平均抗压强度为 33.86MPa，比通过传统重力烧结法制造的等效体积百分比孔隙率的 CPP 高 57%。进行了尺寸偏差和收缩分析，以确定 SFF 样品形成和随后烧结过程中所需的各向异性补偿因素。细胞培养研究表明，该基底支持体外软骨形成，类似于在通过传统重力烧结方法形成的 CPP 上生长的软骨细胞，这在组织学和生物化学上都得到了证实。
