De Giglio E, Cometa S, Cioffi N, Torsi L, Sabbatini L
Department of Chemistry, University of Bari, Via E. Orabona 4, 70126, Bari, Italy.
Anal Bioanal Chem. 2007 Dec;389(7-8):2055-63. doi: 10.1007/s00216-007-1299-7. Epub 2007 May 22.
A polyacrylic acid film was synthesized on titanium substrates from aqueous solutions via an electroreductive process for the first time. This work was done in order to develop a versatile coating for titanium-based orthopaedic implants that acts as both an effective bioactive surface and an effective anti-corrosion barrier. The chemical structure of the PAA coating was investigated by X-ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM) was employed to evaluate the effect of annealing treatment on the morphology of the coatings in terms of their uniformity and porosity. Inductively coupled plasma mass spectrometry was used to measure ion concentrations in ion release tests performed on Ti-6Al-4V sheets modified with PAA coatings (annealed and unannealed). Results indicate that the annealing process produces coatings that possess considerable anti-corrosion performance. Moreover, the availability and the reactivity of the surface carboxylic groups were exploited in order to graft biological molecules onto the PAA-modified titanium implants. The feasibility of the grafting reaction was tested using a single aminoacid residue. A fluorinated aminoacid was selected, and the grafting reaction was monitored both by XPS, using fluorine as a marker element, and via quartz crystal microbalance (QCM) measurements. The success of the grafting reaction opens the door to the synthesis of a wide variety of PAA-based coatings that are functionalized with selected bioactive molecules and promote positive reactions with the biological system interfacing the implant while considerably reducing ion release into surrounding tissues.
首次通过电还原过程从水溶液中在钛基底上合成了聚丙烯酸薄膜。开展这项工作是为了开发一种用于钛基骨科植入物的多功能涂层，该涂层兼具有效的生物活性表面和有效的防腐蚀屏障功能。通过X射线光电子能谱（XPS）研究了PAA涂层的化学结构。采用扫描电子显微镜（SEM）从涂层的均匀性和孔隙率方面评估退火处理对涂层形貌的影响。在对用PAA涂层（退火和未退火）改性的Ti-6Al-4V板材进行的离子释放测试中，使用电感耦合等离子体质谱法测量离子浓度。结果表明，退火过程产生的涂层具有相当的防腐蚀性能。此外，利用表面羧基的可用性和反应活性将生物分子接枝到PAA改性的钛植入物上。使用单个氨基酸残基测试接枝反应的可行性。选择了一种氟化氨基酸，并通过以氟作为标记元素的XPS以及石英晶体微天平（QCM）测量来监测接枝反应。接枝反应的成功为合成各种基于PAA的涂层打开了大门，这些涂层用选定的生物活性分子进行了功能化，促进与植入物周围生物系统的积极反应，同时大幅减少离子释放到周围组织中。
