Shi Yunsong, Pan Teng, Zhu Wei, Yan Chunze, Xia Zhidao
Institute of Life Science, College of Medicine, Swansea University, UK.
State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan, 430074, China.
J Mech Behav Biomed Mater. 2020 Apr;104:103664. doi: 10.1016/j.jmbbm.2020.103664. Epub 2020 Feb 3.
Coralline hydroxyapatite (CHA) has been used in clinical for over 20 years. However, coral is an endanger species and has been banned from mining. In addition, coral artificial bone has slow biodegradation of the defects, hindering the growth of new bone. In order to explore the natural coral artificial bone substitute materials, this work proposed using Selective Laser Sintering (SLS) to fabricate natural calcium carbonate/biopolymer composite imitation coral porous structures, and then the surface of the 3D printing product was transformed into a hydroxyapatite thin layer by hydrothermal conversion reaction. The mechanical properties and porosity were optimized by adjusting the SLS processing parameters including laser power, scanning speed and layer thickness. In the composites with the PLLA of 15 wt%, the SLS processing parameters with the laser power of 15 W, laser scanning speed of 1500 mm/s and single layer thickness of 0.08 mm result in the better mechanical properties. After hydrothermal conversion, the products were confirmed to be a mixture of hydroxyapatite (HA) and calcium carbonate by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray spectroscopy (EDX). The TGA results revealed that increasing the reaction temperature or prolonging the reaction time can increase the degree of hydrothermal reaction and thus promote the transformation of calcium carbonate into hydroxyapatite. The results of cytotoxicity assay and Life/Dead staining showed that the scaffold is not toxic to L929 cells. This work has the materials system innovation and focuses on the study of the effects of the SLS and hydrothermal processes on the mechanical performance and the degree of hydroxylation. Then, the preparation process of imitation coral artificial bone preparation was optimized. it is concluded that the imitation coral artificial bone is a nontoxic biomaterial; however, further study on its osteogenic capacity should be warranted in the future.
珊瑚羟基磷灰石（CHA）已在临床上使用了20多年。然而，珊瑚是濒危物种，已被禁止开采。此外，珊瑚人工骨对缺损的生物降解缓慢，阻碍了新骨的生长。为了探索天然珊瑚人工骨替代材料，本研究提出利用选择性激光烧结（SLS）制备天然碳酸钙/生物聚合物复合仿珊瑚多孔结构，然后通过水热转化反应将3D打印产品的表面转化为羟基磷灰石薄层。通过调整激光功率、扫描速度和层厚等SLS加工参数来优化力学性能和孔隙率。在聚乳酸（PLLA）含量为15 wt%的复合材料中，激光功率为15 W、激光扫描速度为1500 mm/s、单层厚度为0.08 mm的SLS加工参数可使材料具有较好的力学性能。水热转化后，通过X射线衍射（XRD）、傅里叶变换红外光谱（FTIR）和能量色散X射线光谱（EDX）证实产物为羟基磷灰石（HA）和碳酸钙的混合物。热重分析（TGA）结果表明，提高反应温度或延长反应时间可提高水热反应程度，从而促进碳酸钙向羟基磷灰石的转化。细胞毒性试验和活/死染色结果表明，该支架对L929细胞无毒。本研究具有材料体系创新性，重点研究了SLS和水热工艺对力学性能和羟基化程度的影响。进而优化了仿珊瑚人工骨的制备工艺。结果表明，仿珊瑚人工骨是一种无毒的生物材料；然而，未来仍需对其成骨能力进行进一步研究。
