Development of novel magnesium alloys with impoved biocorrosion and mechanical behavior for cardiovascular implants

在加拿大等发达国家，心血管疾病是导致过早死亡的主要原因。许多这类疾病现在都是通过经皮或微创入路植入医疗装置（如心内闭塞装置、血管内支架）来治疗的。大多数种植体是永久性材料（不锈钢，钴），可能导致长期侵蚀，刺激，炎症，穿孔，感染和生长不足。此外，在这些装置存在的情况下，手术取出或再介入是困难的或不可能的。生物可降解的植入物（例如支架）将消除这些问题，纠正潜在的病理，并在问题解决后“消失”。在这项多学科研究中，我们整合了材料工程、电化学、细胞生物学和心血管临床科学与实践方面的专业知识，开发出用于血管内植入物制造的最佳镁合金。最佳合金将逐步开发，以达到生物耐腐蚀性，生物相容性和机械完整性（强度，延展性）；他们将通过最先进的体外和体内（实验动物模型）临床前研究进行测试。这些新的镁合金植入物（支架）有望比现有的植入物具有更高的生物相容性和功能效率。这将最大限度地减少植入后并发症和再次干预的需要，提高患者的生活质量，并降低医疗保健费用。2010年加拿大的数据估计45000个裸金属支架（BMS）的使用价格为550美元/BMS， 45000个药物洗脱支架（DES）的使用价格为1300美元/DES。可生物降解镁合金的开发将为支持公司Baylis Medical创造新技术，并将使他们能够进入植入式治疗设备领域。所创造的知识将对生物医学植入技术产生重大影响。该研究还将为培养材料开发、电化学、生物医学和心血管科学等多学科领域的高素质人才提供良好的平台，使他们能够在加拿大推动这一行业的发展。

Cardiovascular diseases are the leading cause of premature death in developed countries like Canada. Many such diseases are now treated by inserting medical devices (e.g. intracardiac occlusive devices, intra-vascular stents) implanted through percutaneous or minimally invasive approach. Most implants are of permanent materials (stainless steel, cobalt) that may cause long-term erosion, irritation, inflammation, perforation, infection and lack of growth. Also, the surgical extraction or reintervention in the presence of these devices is difficult or impossible. Bio-degradable implants (e.g. stents) would eliminate these problems correcting the underlying pathology and ''fading away'' once the problem is fixed. In this multidisciplinary research, we integrated expertise in materials engineering, electrochemistry, cell biology and cardio-vascular clinical science & practice to develop optimal magnesium (Mg) alloy (s) for intravascular implant fabrication. The optimal alloys will be developed in a step-wise fashion to attain bio-corrosion resistance, bio-compatibility and mechanical integrity (strength, ductility); they will be tested via state-of-the-art in-vitro & in-vivo (with experimental animal model) preclinical studies. These new Mg alloy implants (stents) are expected to be significantly more biocompatible and function-efficient than those currently available. This will minimize postimplantation complications & the need for re-intervention, improve the quality of a patient's life, & decrease health care costs. 2010 figures for Canada estimate the use of 45000 bare metal stents (BMS) at $550/BMS and 45000 drug eluting stents (DES) at $1300/DES. The development of the biodegradable Mg alloys will create new technology for Baylis Medical, the supporting company, and will allow them to branch into the area of implantable therapeutic devices. The knowledge created will have high impact on biomedical implants technology. The research will also provide an excellent platform for training of high quality personnel in the multidisciplinary fields of materials development, electrochemistry, bio-medical & cardiovascular science, so that they will be positioned to advance this industry in Canada.