CAREER: Magnetic Imaging Guided Composite Materials Development

技术摘要：这项由固态和材料化学 (SSMC) 计划支持的职业赠款旨在开发一种新型超高分子量聚乙烯 (UHMWPE) 基复合材料，该复合材料具有特殊的磁性和机械性能，将有助于使用磁粒子成像 (MPI) 技术在各种化学和生物流体环境中对植入型材料进行原位研究。线性、支化和交联的 UHMWPE 聚合物结构将填充专门设计的氧化铁基纳米粒子，以制备新型功能性磁性聚合物复合材料。所制造的复合材料的磁性和机械性能将根据加工条件、成分和所得微观结构进行评估，以确定良好的加工方法和有前途的复合材料配方，该配方具有高磁化灵敏度成像，并具有与基体聚合物相当的良好机械性能。从这些研究中收集的信息将为生物聚合物磨屑形成机制提供宝贵的知识，并将有助于制造具有高度期望的磁性能和良好机械性能和可靠性的创新复合材料系统。这项工作预计将最终实现实时跟踪体内磨损和碎片生成的能力，为提高 UHMWPE 假肢的性能提供变革性工具。此外，所提出的磁性复合材料的设计和监测将直接影响MPI技术的进步，并可能促进用于体内生物医学应用的聚合物生物材料的台式测试工具的开发。非技术摘要：聚乙烯广泛用作关节假体制造中的成分。这种材料的一个主要缺点是它可能会经历过度磨损，导致植入物过早松动，进而导致失败和复杂的更换修复手术。研究表明，人工关节置换术中的聚乙烯磨损并不总是相同，并且很难仅用机械因素来解释。如果聚乙烯轴承过早过度磨损，聚合物的化学降解和氧化会显着降低其机械阻力，并导致磨损过程加速。虽然已经对以前使用的聚乙烯髋臼杯进行了离体研究，以了解导致植入失败的因素，但其降解机制仍不完全清楚。对植入物中使用的聚乙烯材料在承受机械和化学应力时的结构完整性进行改进评估，将提供有关材料耐用性的宝贵信息，并有助于预测其随时间的磨损和降解。为了研究植入材料在各种化学和生物流体环境中的实时降解，拟议项目旨在开发新型聚乙烯复合材料，可以使用一种称为磁粒子成像（MPI）的新兴成像方式进行研究。拟议的研究将改变聚乙烯植入材料的磨损碎片监测，仅在美国每年就会影响 100 万人接受髋关节和膝关节置换手术。该项目的教育影响将建立在当前通过开发跨学科课程和实践研究项目来教育高中生、本科生和研究生的举措的基础上，这些课程和实践研究项目将结合材料制造和成像工具之间的相互作用。此外，还将为 K-12 学生开发四个适应性级别的模块化“旅行磁力秀”，并将在当地学校和科学博物馆展示。此外，还将设立一个新的“CWRU女性化学研讨会系列”，为化学专业的研究生和研究生提供指导和培训平台。该计划将促进每月的讨论和研讨会，以解决女科学家职业发展的重要方面。

TECHNICAL SUMMARY:This CAREER grant supported by the Solid State and Materials Chemistry (SSMC) program aims to develop a novel class of ultra-high molecular weight polyethylene (UHMWPE)-based composites with special magnetic and mechanical properties that will facilitate the in situ study of implant-type materials in various chemical and biological fluid environments using magnetic particle imaging (MPI) technologies. Linear, branched and cross-linked UHMWPE polymer structures will be filled with specifically engineered iron oxide-based nanoparticles to prepare new functional magnetic polymer composites. The magnetic and mechanical properties of the fabricated composites will be evaluated as a function of processing conditions, compositions, and resulting microstructures in order to identify good processing approaches, and promising composite formulations that have high magnetization sensitivity for imaging, combined with good mechanical properties that are comparable to the matrix polymer. The information gathered from these studies will provide valuable knowledge on wear debris formation mechanisms of biopolymers and will contribute to the fabrication of innovative composite material systems possessing highly desired magnetic properties and good mechanical performance and reliability. This work is expected to lead ultimately to the ability to track wear and the generation of debris in real time inside the body, providing a transformational tool for improving the performance of UHMWPE prostheses. Moreover, the design and monitoring of the proposed magnetic composites will directly influence the advancement of MPI technology and possibly enable the development of bench side testing tools for polymer biomaterials that will be used for in vivo biomedical applications. NON-TECHNICAL SUMMARY:Polyethylene is widely used as a component in the fabrication of joint prostheses. A major downside of this material is that it can undergo excessive wear leading to premature loosening of the implant, which in turn can lead to failure and complicated replacement revision surgeries. Studies have shown that polyethylene wear in artificial joint replacements are not always identical and are not easily explained by exclusively mechanical factors. In cases of premature and excessive wear of polyethylene bearings, chemical degradation and oxidation of the polymer can significantly lower its mechanical resistance and result in an accelerated wear-off process. While ex vivo studies have been conducted on previously used polyethylene acetabular cups to understand the factors contributing to implant failure, the degradation mechanism is still not completely understood. An improved assessment of the structural integrity of the polyethylene material used in implants as subjected to mechanical and chemical stress will provide valuable information on the material's durability, and can help predict its wear and degradation over time. To study the real-time degradation of implant materials in various chemical and biological fluid environments, the proposed project aims to develop new polyethylene composite materials that can be investigated using an emerging imaging modality called magnetic particle imaging (MPI). The proposed research will transform the wear debris monitoring of polyethylene implant materials and impact annually one million people in the U.S. alone who undergo hip and knee replacement surgeries. The educational impact of this project will build on current initiatives to educate high school, undergraduate and graduate students through the development of cross-disciplinary courses and hands-on research programs that will incorporate the interplay between materials fabrication and imaging tools. Moreover, a modular "Traveling Magnetism Show" will be developed for K-12 students at four adaptive levels and will be showcased in local schools and science museums. In addition, a new "Women in Chemistry Workshop Series at CWRU" will be established to provide a mentoring and training platform for graduate and post-graduate female chemistry students. This program will facilitate monthly discussions and workshops to tackle important aspects of career advancement specific to women scientists.