Designing and developing processes for plasma immersion ion implantation of metallic surfaces for improving bio- and hemo-compatibility for biomedical devices

由于每年实现的生物医学植入物数量很高且不断增加，因此植入器械与人体内生物环境之间的相互作用是一个关键问题。这一点尤其适用于支架的心脏、血管和神经系统应用，其中血液和生物相容性在植入物的最终结果中起着关键作用。当金属器械在血管系统中的整合不正确时，会发生器械失效;这种原因可能导致局部凝血、炎症、细胞损伤和增生，最终导致血管因凝血而再狭窄。不可吸收性合金需要耐腐蚀，以避免有毒离子的释放，而可吸收性合金则需要控制其腐蚀速率。等离子体浸没离子注入和磁控溅射表面改性是一种创新的方法，提供可吸收和不可吸收的材料，同时保持本体的优良的生物性能。由于材料的表面是与身体组织发生相互作用的地方，因此等离子体改性既可以产生阻挡层，以阻止有毒离子（Ni+，Cr 6+，Mn 2+等）的扩散，并为细胞活力提供更有利的环境。在这种情况下，可以调整表面化学组成和物理结构，从而获得更好的生物反应。本项目的最终目标是设计和验证基于离子注入的等离子体表面工艺，赋予材料有效的生物相容性。这一总体目标将通过多学科方法实现，即研究等离子体参数和工艺，它们与改性合金的表面化学和结构的相关性，评估腐蚀和生物学特性，以及将定义的工艺转移到不同的产品。Plasmionique参与该项目对于将所发现的程序应用于半成品和扩大规模至关重要，从而为加拿大社会和经济带来持续的医疗、科学和工业利益。

The interaction between an implanted device and the biological environment inside the human body is a critical issue due to the high and increasing number of biomedical implants realized every year. This is dramatically true especially for cardiac, vascular and neurologic applications for stents, where hemo- and biocompatibility play a key role in the final outcome of the implant. Failure of the device occurs when there is an incorrect integration of metallic devices in the vascular system; this cause can lead to localized coagulation, inflammation, cellular damage and hyperplasia, conducing to a final restenosis of the vessel because of clotting. While non-absorbable alloys need to be corrosion resistant, to avoid the release of toxic ions, absorbable alloy share required to have their corrosion rate controlled. Surface modification by plasma immersion ion implantation and magnetron sputtering is an innovative way to provide both absorbable and non-absorbable materials excellent biological properties while bulk ones are preserved. Since the surface of a material is the place where interactions with body tissues develop, plasma modification can both create a barrier layer to hamper the diffusion of toxic ions (Ni+, Cr6+, Mn2+, etc.) and provide a more favorable environment to cell viability. It is possible in this case to tailor surface chemical composition and physical structure so that a better biological response is obtained. The final goal of this project is the designing and validation of ion-implantation-based plasma surface processes conferring to the material effective biocompatibility. This overall objective will be attained through a multidisciplinary approach, namely the study of the plasma parameters and processes, their correlation with surface chemistry and structure of the modified alloys, the assessment of corrosion and biological properties and the transfer of the defined processes to different products. The participation of Plasmionique in the project will be fundamental for the application of the found procedures to semifinished products and to scaling up, so that consistent medical, scientific and industrial benefits will arise for Canada society and economy.