Chrzanowski Wojciech, Neel Ensanya Ali Abou, Armitage David Andrew, Knowles Jonathan Campbell
Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, 256 Gray's Inn Road, London WC1X 8LD, UK.
Acta Biomater. 2008 Nov;4(6):1969-84. doi: 10.1016/j.actbio.2008.05.010. Epub 2008 Jun 9.
In this paper, the bioactive properties of Ni-Ti alloy after different surface treatments were evaluated in different media (Hanks' balanced salt solution, Dulbecco's modified Eagle's medium and osteogenic). Evaluation was performed on the basis of X-ray photoelectron spectroscopy and atomic force microscopy studies after immersing samples for up to 24h in the relevant media. This allowed assessment of the kinetics of Ca(2+) and P(5+) precipitation and early interaction of the media with surfaces. In addition, the surface free energy was measured and the influence of heat treatment on phase transformation temperatures and rate of nickel and titanium ion release was investigated. The most favourable bioactive properties were observed for simply ground Ni-Ti samples when evaluated in HBSS, which showed similar properties to reference positive samples (BioactiveTi). On the other hand, samples heat-treated at 600 degrees C showed very low levels of precipitation of Ca and P. Most interestingly, evaluation in the media containing organic components (protein, vitamins, antibiotics and drugs) revealed that bioactivity for all the samples was at the same level (except for the reference negative) irrespective of the surface preparation method. It demonstrated that organic components interact with the surface rapidly, forming a thin protein layer, and this altered the surface properties of the samples, making them bioactive. No significant difference in kinetics of the Ca(2+) and P(5+) precipitation were observed. Nevertheless, further ion release and chemical composition evaluation revealed that alkali treatment and spark oxidation cannot be considered as a useful for biomedical application due to very high levels of Ni in the top layer (alkali-treated) and high rate of Ni release (spark-oxidized and alkali-treated).
在本文中，对经过不同表面处理的镍钛合金在不同介质（汉克斯平衡盐溶液、杜尔贝科改良伊格尔培养基和成骨培养基）中的生物活性特性进行了评估。在将样品浸入相关介质长达24小时后，基于X射线光电子能谱和原子力显微镜研究进行了评估。这使得能够评估Ca(2+)和P(5+)沉淀的动力学以及介质与表面的早期相互作用。此外，还测量了表面自由能，并研究了热处理对相变温度以及镍和钛离子释放速率的影响。在HBSS中评估时，简单研磨的镍钛样品表现出最有利的生物活性特性，其特性与参考阳性样品（生物活性钛）相似。另一方面，在600摄氏度下热处理的样品显示出极低的Ca和P沉淀水平。最有趣的是，在含有有机成分（蛋白质、维生素、抗生素和药物）的介质中进行评估时发现，无论表面处理方法如何，所有样品的生物活性处于同一水平（参考阴性样品除外）。这表明有机成分与表面迅速相互作用，形成一层薄的蛋白质层，这改变了样品的表面特性，使其具有生物活性。未观察到Ca(2+)和P(5+)沉淀动力学的显著差异。然而，进一步的离子释放和化学成分评估表明，由于顶层（碱处理）中镍含量非常高以及镍释放速率高（火花氧化和碱处理），碱处理和火花氧化不能被认为适用于生物医学应用。
