GOALI: Tuning Degradation Properties of Metallic Implants through Polymeric Coatings and Surface Texture

美国每年约有150万例关节镜手术（界面螺钉、缝线锚钉）。然而，目前这一代可生物降解的骨科植入物还没有完全达到预期。与常用的金属或聚合物植入物相比，镁合金联合收割机将两者的优点结合到一种材料中。例如，镁螺钉可以制成自攻螺钉，尺寸比聚合物螺钉小，最大限度地减少植入时对周围骨骼的损伤。然而，它们也是可降解的，从而打开了完全生物可吸收金属的可能性。也就是说，镁的主要局限性是其降解速率对于大多数临床应用来说太快。该研究项目将研究如何使用镁上的薄屏障涂层来延长降解时间，这将带来下一代完全可降解的植入物，其固定性能与目前可用的金属相似，而无需后续手术。作为整体努力的一部分，同时和综合教育计划也旨在培训学生，并为他们准备植入材料所带来的独特挑战。与ConMed公司的合作将提供博士奖学金和工业技能之间的紧密结合，以便更彻底地为学生毕业后的工作做好准备。该研究将广泛分布到课堂教学和初中和高中学生在本研究项目中，生物降解聚合物涂层将被调查，以控制镁植入物的生物吸收，描绘涂层工艺变量，涂层成分，机械性能和生命周期性能之间的相互关系。结果将以目前可用的生物可吸收材料为基准。通过改变聚合物涂层的组成和分子量以及通过加工条件改变涂层的结晶度和厚度，假设可以控制水的可用性，以定制植入物的生物吸收特征。将解决的研究线包括以下1：如何在镁表面的可降解聚合物涂层控制水的可用性？第二章：在聚合物涂层镁模型植入物上，早期前成骨细胞附着，随后增殖和成熟为骨形成细胞的事件是什么？3;镁表面的粗糙度如何影响镁/聚合物材料的生物降解？这些问题的答案将能够预测随着时间的推移退化行为，以指导未来设备的设计。

There are approximately 1.5 million arthroscopic procedures (interference screws, suture anchors) per year in the United States. However, the current generation of biodegradable orthopedic implants have not fully met expectations. Compared to commonly available metallic or polymeric implants, magnesium alloys combine the advantages of both into one material. Magnesium screws, for instance, can be made self-tapping and smaller in size than polymer screws, minimizing injury to the surrounding bone upon implantation. Yet, they are also degradable, opening up the possibility of fully bioresorbable metals. That said, the major limitation of magnesium is that its rate of degradation is too rapid for most clinical applications. This Grant Opportunity for Academic Liaison with Industry (GOALI) research project will investigate how thin barrier coatings on magnesium can be used to extend degradation time frames, which will usher in the next generation of fully degradable implants with fixation properties similar to currently available metals without the need for subsequent surgeries. As part of the overall effort, a concurrent and integrated educational program also is designed to train students and prepare them for the unique challenges presented by implantable materials. A collaboration with ConMed Corporation will offer tight integration between PhD scholarship and industrial skills in order to more thoroughly prepare students for jobs after graduation. The research will be broadly distributed into both classroom instruction and to middle and high school studentsIn this research project, biodegradable polymer coatings will be investigated to control the bioabsorption of magnesium implants delineating the interrelationships between coating process variables, coating composition, mechanical properties and life-cycle performance. Results will be benchmarked against currently available bioresorbable materials. By varying the composition and molecular weight of the polymer coating as well as changing the crystallinity and the thickness of the coating through processing conditions, it is hypothesized that water availability can be controlled in order to customize bioabsorption profiles of the implant. Lines of research that will be addressed include the following 1: How is water availability at the magnesium surface controlled by a degradable polymer coating? 2: What are the events of early pre-osteoblasts attachment followed by their subsequent proliferation and maturation into bone forming cells on polymer-coated magnesium model implants? 3; How does roughness of the magnesium surface affect the biodegradation of magnesium/polymer materials? The answers to these questions will enable predictions of degradation behavior over time to guide the design of future devices.