3D打印β-TCP多孔复合支架的力学和生物学特性

目的 研究3D打印β磷酸三钙［β-Ca3(PO4)2，β-TCP］多孔复合支架的力学和生物学特性，为进一步动物实验中复合支架的设计提供指导。方法 用新型可降解材料聚柠檬酸-1,8-辛二醇酯［poly(1,8-octanediol citrate)，POC］为粘合剂，采用熔融成型（fused deposition modeling，FDM）技术实现β-TCP支架的3D打印，并用多肽甘氨酸-精氨酸-甘氨酸-天冬氨酸-丝氨酸（Gly-Arg-Gly-Asp-Ser，GRGDS）对复合支架修饰，以改善复合支架的细胞黏附性。使用光学显微镜和扫描电镜观察复合支架的微观孔隙结构，使用材料试验机对复合支架进行压缩测试，并测量支架的水表面接触角；通过体外细胞实验检测支架的细胞黏附率和促细胞增殖能力；利用支架修复SD大鼠颅骨缺损模型，进一步研究其体内成骨能力。结果 多肽在复合支架上均匀分布且不失活；复合多肽后支架的微观孔隙结构发生改变，细胞黏附率提高，但支架压缩模量、水表面接触角和体内成骨能力等特性未受明显影响。结论 多肽修饰后的β-TCP多孔复合支架细胞黏附能力明显改善，而力学、亲水性和体内成骨能力等未受明显影响。研究结果为临床骨缺损修复支架的构建提供新思路，也为该支架技术的进一步临床应用提供实验室依据。
Objective To study the mechanical properties and biological characteristics of 3D-printed porous β-tricalcium phosphate ［β-Ca3(PO4)2, β-TCP］ scaffolds, so as to provide guidance for the design of composite scaffolds in animal experimentation. Methods Poly 1,8-octanediol citrate (POC), a kind of novel biodegradable materials, was used as the adhesive. The 3D-printed porous β-TCP scaffolds were fabricated by fused deposition modeling (FDM) technology, and Gly-Arg-Gly-Asp-Ser (GRGDS), a kind of polypeptides, was added into the scaffolds to improve the adhesive property of cells. The optical microscope and scanning electron microscope (SEM) were used to observe the micro-pore architectures of those scaffolds. The material testing machine was used to conduct compressive test on the scaffolds, and the water contact angles of the scaffolds were measured. The cell adhesion rate and proliferation rate of the scaffolds were also tested by in vitro cell experiment. The model of SD rat skull defects was repaired by the scaffolds, and the osteogenic ability in vivo was further studied. Results The GRGDS, remaining active, was evenly distributed in the composite scaffolds. The micro-pore architectures of the polypeptide modified scaffolds changed, with improvement in cell adhesion rate, while the compressive modulus, water contact angle and osteogenic ability in vivo of the scaffolds were not obviously affected. Conclusions The cell adhesion capacity of β-TCP composite scaffolds modified by polypeptide improved significantly, while the mechanical properties and hydrophilicity, osteogenic ability in vivo of the scaffolds were not affected very much. These research results provide new ideas for reconstruction of scaffolds for repairing bone defects in clinic, and a laboratory basis for further clinical application of this scaffold.