Wu Shuilin, Liu Xiangmei, Chan Y L, Ho J P Y, Chung C Y, Chu Paul K, Chu C L, Yeung K W K, Lu W W, Cheung K M C, Luk K D K
Department of Physics and Materials Science, City University of Hong Kong, Kowloon, Hong Kong.
J Biomed Mater Res A. 2007 Jun 15;81(4):948-55. doi: 10.1002/jbm.a.31115.
Porous NiTi shape memory alloys are one of the promising biomaterials for surgical implants because of their unique shape memory effects and porous structure with open pores. However, the complex surface morphology and larger area of porous NiTi compared to dense NiTi make it more vulnerable from the viewpoint of release of nickel, which can cause deleterious effects in the human body. It is also more difficult to modify the exposed surfaces of a porous structure using conventional surface modification technologies. In this work, oxidation in conjunction with postreaction heat treatment was used to modify the surfaces of porous single-phase NiTi prepared by capsule-free hot isostatic pressing to mitigate Ni leaching and enhance the surface properties. Differential scanning calorimetry thermal analysis, uniaxial compression tests, inductively-coupled plasma mass spectrometry, and cell cultures reveal that porous NiTi alloys oxidized at 450 degrees C for 1 h have an austenite transition temperature below 37 degrees C, excellent superelasticity, lower nickel release, and no cytotoxicity.
多孔镍钛形状记忆合金因其独特的形状记忆效应和具有开放孔隙的多孔结构，是外科植入物中很有前景的生物材料之一。然而，与致密镍钛相比，多孔镍钛复杂的表面形态和更大的面积使其从镍释放的角度来看更易受到影响，镍释放会对人体造成有害影响。使用传统的表面改性技术对多孔结构的暴露表面进行改性也更加困难。在这项工作中，氧化结合后反应热处理被用于改性通过无包套热等静压制备的多孔单相镍钛的表面，以减轻镍的浸出并增强表面性能。差示扫描量热法热分析、单轴压缩试验、电感耦合等离子体质谱和细胞培养表明，在450℃氧化1小时的多孔镍钛合金具有低于37℃的奥氏体转变温度、优异的超弹性、较低的镍释放且无细胞毒性。
