State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, People's Republic of China.
Biomed Mater. 2011 Apr;6(2):025012. doi: 10.1088/1748-6041/6/2/025012. Epub 2011 Mar 25.
TiN coating has been demonstrated to improve the biocompatibility of bare NiTi alloys; however, essential biocompatibility differences between NiTi alloys before and after TiN coating are not known so far. In this study, to explore the underlying biological mechanisms of biocompatibility differences between them, the changes of bare and TiN-coated NiTi alloys in surface chemical composition, morphology, hydrophilicity, Ni ions release, cytotoxicity, apoptosis, and gene expression profiles were compared using energy-dispersive spectroscopy, scanning electron microscopy, contact angle, surface energy, Ni ions release analysis, the methylthiazoltetrazolium (MTT) method, flow cytometry and microarray methods, respectively. Pathways binding to networks and real-time polymerase chain reaction (PCR) were employed to analyze and validate the microarray data, respectively. It was found that, compared with the bare NiTi alloys, TiN coating significantly decreased Ni ions content on the surfaces of the NiTi alloys and reduced the release of Ni ions from the alloys, attenuated the inhibition of Ni ions to the expression of genes associated with anti-inflammatory, and also suppressed the promotion of Ni ions to the expression of apoptosis-related genes. Moreover, TiN coating distinctly improved the hydrophilicity and uniformity of the surfaces of the NiTi alloys, and contributed to the expression of genes participating in cell adhesion and other physiological activities. These results indicate that the TiN-coated NiTi alloys will help overcome the shortcomings of NiTi alloys used in clinical application currently, and can be expected to be a replacement of biomaterials for a medical device field.
氮化钛涂层已被证明能提高裸露的镍钛合金的生物相容性；然而，迄今为止，尚不清楚氮化钛涂层前后镍钛合金的基本生物相容性差异。在这项研究中，为了探索它们之间生物相容性差异的潜在生物学机制，分别采用能谱仪、扫描电子显微镜、接触角、表面能、镍离子释放分析、噻唑蓝（MTT）比色法、流式细胞术和基因芯片方法比较了裸露和氮化钛涂层镍钛合金在表面化学成分、形貌、亲水性、镍离子释放、细胞毒性、细胞凋亡和基因表达谱方面的变化。采用通路结合网络和实时聚合酶链反应（PCR）分别对基因芯片数据进行分析和验证。结果发现，与裸露的镍钛合金相比，氮化钛涂层显著降低了镍钛合金表面的镍离子含量，并减少了镍离子从合金中的释放，减弱了镍离子对与抗炎相关基因表达的抑制作用，同时抑制了镍离子对凋亡相关基因表达的促进作用。此外，氮化钛涂层明显改善了镍钛合金表面的亲水性和均匀性，有助于参与细胞黏附等生理活动的基因表达。这些结果表明，氮化钛涂层镍钛合金有助于克服目前临床应用中镍钛合金的缺点，有望成为医疗器械领域生物材料的替代品。
