医用镍钛形状记忆合金羟基磷灰石涂层的制备及其生物活性

Preparation and bioactivity of hydroxyapatite in medical NiTi-shaped memory alloy

背景:目前多采用等离子喷涂技术在钛及其合金表面涂覆羟基磷灰石涂层,制备成复合材料。但由于羟基磷灰石与钛合金基体的热膨胀系数相差较大,涂层在冷却过程中易产生脱落。目的:在医用镍钛形状记忆合金表面制备致密、均匀的羟基磷灰石生物陶瓷涂层,利用动物实验考查镍钛/羟基磷灰石涂层材料的生物相容性。方法:利用阴极旋转法在低温条件下从含钙、磷离子的电解水溶液中在镍钛形状记忆合金表面沉积了磷酸钙涂层,经碱处理获得羟基磷灰石涂层。分析工艺参数对涂层结构的影响。利用动物植入实验对该复合材料的生物活性进行研究,并与镍钛/羟基磷灰石与Ca3(PO3)2?2H2O混合涂层复合材料、医用镍钛形状记忆合金、医用钛合金进行对比。结果与结论:电化学沉积-碱处理方法适合在镍钛形状记忆合金表面制备羟基磷灰石生物活性陶瓷涂层,沉积电压、温度对涂层结构有强烈影响。4种不同材料植入动物体内后周围均出现不同程度的组织增生,在骨膜组织切片中都可见软骨细胞且有骨小梁形成,涂覆有羟基磷灰石涂层的植入材料组织反应较轻,相应的组织切片中所显示出的软骨细胞、骨小梁数量最多,分布均匀,表明羟基磷灰石涂层提高了医用镍钛形状记忆合金的生物活性。

BACKGROUND：At present,many plasma spraying technology in titanium and its surface of alloys coated hydroxyapatite（HA） coatings,and composite materials were prepared. However,the HA coating usually desquamated during the period of cooling due to the different expansion coefficient between HA and titanium alloy substrate. OBJECTIVE：To prepare dense,uniform coating of HA bioceramic on the surface of medical niti-shaped memory alloy,and to investigate the biocompatibility of NiTi/HA composite by animal experiment. METHODS：HA coatings on the surface of NiTi-shaped memory alloy were prepared via electrochemical deposition from aqueous electrolytes containing calcium and phosphorus ions at low temperature and then treated with alkaline solution. The effects of technological parameter on the structure of coating were analyzed. The bioactivity of the composite materials was studied by animal implantation experiment,and compared with NiTi/HA and Ca3（PO3） 2-2H2O hybrid coating composite materials,medical NiTi-shaped memory alloy,and medical Ti alloy. RESULTS AND CONCLUSION：The electrochemical-deposition alkali treatment is suitable to prepare bioactive ceramic coating of HA on the surface of NiTi-shaped memory alloy. Deposition voltage and temperature have strong influence on the coating structure. There were varying degrees of hyperblastosis in the surrounding region after 4 kinds of materials implanted in animal. Chondrocyte and trabecular bone formation could be seen in periosteal tissue sections. Implant materials tissue coated with HA coating had a mild reaction,the number of chondrocyte and trabecular bone was the largest in the corresponding histological section and uniform distribution. The results showed that HA coating improved the bioactivity of medical niti-shaped memory alloy.