激光熔覆技术制备的纳米钽-钛合金棒结构特征及生物相容性

Structural characteristics and biocompatibility of a new Nano-Ta-Ti alloy rod fabricated by laser melting technique

目的：运用激光熔覆技术制备新型纳米钽-钛合金棒并研究其结构特征及生物相容性，为临床选用内固定提供依据。方法以纳米级钽粉（Ta，Tantalum）为原料，利用激光熔覆技术制备两侧具有对称纳米钽涂层的新型钛合金棒。SEM观察微观界面结构、测量孔隙直径并分析金相成分。采用MTT细胞毒性试验和ALP活性检测评价新型纳米钽-钛合金对MC3T3-E1细胞增殖和分化性能的影响。结果扫描电镜下观察到试样的Ta涂层表面呈粗糙多孔结构，钽粉颗粒间致密熔融，孔隙直径平均在200--300μm之间，加工过程前后成分一致；成分分析结果显示熔覆过程并未产生新的元素。两组材料皆可明显促进MC3T3-E1细胞增值，但新型纳米钽-钛合金性能更为优异，同时能够促进成骨细胞的骨化，差异具有统计学意义。结论激光熔覆技术可成功实现钽与医用钛合金的冶金结合，并使其拥有良好的表面结构和生物相容性。

Objective To evaluate the structural characteristics and biocompatibility of a novel nano-Ta-Ti alloy rod for its potential application in internal fixation. Methods Ta coating of a Ti alloy rod with nano-Ta （tantalum） powder was performed using laser melting with symmetrical grooves repleted with nano-Ta powder along the whole length. The microstructure of the cross section of Ta-Ti alloy rod, pore diameter and components of the coating were analyzed using scanning electron microscopy. The influence of this nano-Ta-Ti alloy on proliferation and differentiation of MC3T3-E1 cells was evaluated by MTT cytotoxicity test and ALP activity test. Results Under scanning electron microscope, the Ta-coating surface presented with a gross porous （200-300μm） structure with dense fusion between Ta particles, and no new element was produced after laser melting. Biocompatibility evaluation showed that Ti alloys with and without Ta coating both promoted the proliferation of MC3T3-E1 cells, but the coated alloy showed better performance and obviously promoted the differentiation of the osteoblasts. Conclusion Alloying between Ta and Ti can be accomplished successfully by laser melting technique, and the alloy obtained has ideal surface structure and good biocompatibility.