Development and validation of novel bioactive biodegradable metals for high performance biomaterials

生物医疗器械行业的梦想是为患者和临床医生提供新一代植入物，这种植入物可以发挥其功能，然后在宿主体内溶解，消除目前永久性植入物的有害影响。生物可降解金属具有强度、延展性和可降解性的组合，被视为制造这些梦寐以求的植入物的理想材料。在过去的10年里，发表的关于可生物降解金属的论文显著增加，从2005年的不到50篇增加到2000多篇。这些金属一直吸引着学术界和工业界的研究人员，因为它们可能会给医疗产品带来革命性的变化。未来的趋势是增加生物活性，探索需要暂时存在承载植入物的新的临床应用。最新的进展之一是引入了其用于骨支架的多孔结构。我是第一个引入多孔可生物降解金属支架的人之一，在《自然科学报告》上报道了多孔铁-聚(乳酸-乙醇酸)的新型复合材料。 在过去的6年里，我独立从事可生物降解金属的研究，明确了我的长期目标，即在对材料-工艺-腐蚀关系有基本了解的情况下，开发世界公认的创新生物材料方面的专业知识。在5年内，我将解决当前对生物活性生物材料的挑战和需求，并探索可生物降解金属的新应用。在一个方向上，我将针对骨支架的应用开发新型生物活性铁基多孔金属。多孔铁将是通过转化涂层技术结合钙磷和银离子等生物活性化合物的主干。另一个方向是针对其在泌尿外科的新应用，开发新型可生物降解金属。在与泌尿科医生讨论后，我了解到对坚固的临时输尿管支架的需求尚未得到满足，在这种情况下，工程学应该发挥作用。镁锌合金是制作力学性能优于聚合物支架的理想材料。这两个方向的工作都是为了通过了解所开发材料的工艺-结构-性能关系来产生持久的影响。 我将提供有效的证据，证明生物活性多孔铁和新型合金分别作为支架和输尿管支架的新技术平台具有最佳的力学和腐蚀性能。我将既提高知识，又培养高素质的人才，以获得加拿大关键科学和工程领域的专业知识。招募了四名研究生，并开始了这项计划中的工作，取得了一些初步成果。NSERC的支持对他们的继续培训和我们年轻研究小组的建立起到了重要作用。

The dream of biomedical device industries is to provide patients and clinicians with a new generation of implants that can perform its function then dissolve in the host body, eliminating the harmful effects of current permanent implants. Biodegradable metals, having the combination of strength, ductility and degradability, have been viewed as the ideal materials for making those dreamed implants. Published works on biodegradable metals have been significantly increasing from less than 50 papers in 2005 to more than 2,000 over 10 years. These metals have been attracting researchers in academia and industries alike as they can potentially revolutionize the medical products. The future trend goes toward adding bioactivities and exploring new clinical applications that require a temporary presence of load bearing implants. One of the latest development is the introduction of its porous structure for bone scaffolds. I am among the first to introduce porous biodegradable metal scaffolds with the works on new composites of porous iron-poly(lactic-co-glycolic acid) as reported in Nature's Scientific Reports. Having worked independently in biodegradable metals research in the past 6 years, I defined my long-term objective to develop world-recognized expertise in novel innovative biomaterials with fundamental understanding of their material-process-corrosion relationship. Within 5 years, I will address the current challenge and need for bioactive biomaterials and explore new applications of biodegradable metals. At one direction, I will develop new class of bioactive iron-based porous metals in view of bone scaffold applications. The porous iron will be the backbone for incorporating bioactive compounds like Ca-P and Ag ions via conversion coating technique. Another direction is on developing novel biodegradable metals in view of new application in urology. Having discussed with urologists, I understood there is an unfulfilled need for strong temporary ureteral stents where engineering should take the role. Magnesium and zinc alloys are the ideal materials to make the stent with superior mechanical property than that made of polymers. The works in both directions are intended to make a lasting effect by understanding process-structure-property relationship of the developed materials. I will bring valid evidence of the optimum mechanical and corrosion properties of bioactive porous iron and novel alloys as new technological platform applicable to scaffold and ureteral stents, respectively. I will both advance knowledge and train high qualified personnel to acquire expertise in the key areas of science and engineering for Canada. Four graduate students were recruited and have been initiating works planned in this program with some preliminary results. The support from NSERC plays an important role to the continuation of their training and the establishment of our young research group.