多孔钽“骨小梁”结构可控制造与纳米化研究

Porous tantalum noted as trabecular metal has excellent osteoinductive effect. However, due to the high melting point and high oxidizablility at high temperature, it is difficult to fabricate porous tantalum scaffold with bio-inspired micro/nanostructure by either traditional manufacturing process or additive manufacturing process. We present a novel process to fabricate micro/nanostructured porous tantalum scaffold by combining SLS (selective laser sintering) with in situ reduction of molten salt electrolysis. Firstly, the trabecular-inspired structure is designed for the SLS process; Secondly, Ta2O5 scaffold is fabricated by SLS at 1150℃; Then, tantalum scaffold with porous micro/nanostructure contributing to cell adhesion is developed by in situ reduction of molten salt electrolysis to deoxidize the Ta2O5 scaffold. Adopting the reverse manufacturing method--"first form, then material", we may overcome the difficulties in direct 3D printing of the metals with high melting point, easily oxidized and difficult for building nanostructure. The porous tantalum scaffold is comprised of 300-600μm trabecular-inspired microstructure, 10-30μm micro slits and nanostructure that further promoting cell adhesion, growth and migration. It may be a new method to the fabrication of scaffold with Bio-inspired structure by additive manufacturing for the metals with high melting point (e.g. tantalum, niobium, bismuth, etc.). It could also promote the application of porous tantalum in medical field.

多孔钽具有优异的骨诱导效应，被誉为”骨小梁金属“，但由于熔点高、高温下易氧化，目前已有的增材制造方法和传统工艺在微观仿生结构精确成形和纳米化方面均存在很大难度。提出采用选区激光烧结结合原位熔盐电解还原制造宏微纳结构一体化多孔钽植入物：通过仿生设计构建面向SLS工艺的仿骨小梁结构；在1150℃烧结温度下通过SLS制备五氧化二钽宏微结构支架；通过原位熔盐电解还原脱氧实现微孔结构的纳米化，促进细胞粘附。该方法采用先“成形”，后“成材”的逆向制造方案，克服了直接打印高熔点金属难熔化、易氧化和不易构建纳米结构的难点。支架内部结构包括了尺度在300-600um的仿骨小梁结构，同时也包含了尺度在10-30um的粉粒间二级微观缝隙和纳米结构，更有利于细胞的粘附、生长和迁移。对于各种难熔金属（钽、铌、铋等）的多孔结构及纳米化，有望建立仿生结构增材制造方法的新途径，对促进多孔钽在医学领域的应用具有重要意义。

多孔钽具有优异的骨传导效应，被誉为”骨小梁金属“，但由于熔点高、高温下易氧化，目前已有的增材制造方法和传统工艺在微观仿生结构精确成形和纳米化方面均存在很大难度。提出“先成形、后成材”的逆向（反向）制造概念，利用“直写3D打印+烧结”的逆向制造方法完成了多孔钽支架的制备，实现了宏微结构一体化多孔钽支架的主动控制成形，解决了多孔钽熔点高、宏微一体多孔结构成形难的问题；通过对微观结构形态的调控生长实现了多孔钽支架的表面改性，提高了多孔钽支架的生物活性和成骨性能，促进了多孔钽支架表面的骨质沉积；采用“直写3D打印+烧结”制造方法可以实现重量轻、低弹性模量的钽基生物高熵合金多孔支架的的低成本制备，解决了生物高熵合金各组元熔点差异大、直接增材制造多孔结构难度大的问题。本项目的研究有望建立各种难熔金属（钽、铌、铋等）的多孔支架制备的新途径，对促进多孔钽在医学领域的应用具有重要意义。本项目在Carbon, Journal of the European Ceramic Society, Materials Letters和机械工程学报等杂志发表论文16篇（其中SCI：10篇，EI：6篇）；申请国家发明专利授权10项，其中已授权7项；培养博士生2名，硕士生9名。