GOALI: Additive Manufacturing of Wear Resistant Metal-Composites for Biomedical Devices

在大多数生物医学设备中，金属生物材料通常是用于承重植入物的耐磨部件的选择。然而，人们越来越担心体内的金属离子会导致金属中毒，并在一些患者中造成严重的组织和骨骼损伤。与聚合物组件相比，金属装置提供更大的运动，更高的稳定性和99%以上的磨损碎片减少；然而，近年来由于金属离子释放问题，这些金属植入物的使用显著下降。这项学术与工业联络资助机会（GOALI）奖支持基础研究，以了解金属陶瓷复合材料，这种复合材料可以通过在接触表面原位形成自润滑膜来减少人体中金属离子的释放。本研究结果为解决全髋关节置换术、全膝关节置换术等负重假体长期存在的金属离子释放问题提供了方向，延长了各年龄段患者的假体使用寿命。在承重植入物中，当两个金属表面接触时，会产生磨损引起的损伤，从而在人体内释放金属离子。该项目的目标是使用自润滑陶瓷基摩擦膜，最大限度地减少人体内金属植入物释放的金属离子。这些膜在金属-陶瓷复合材料的接触面原位形成，并且类似于承重植入物中两个硬关节面之间的软骨。该项目将产生与金属陶瓷复合材料加工相关的基础知识，这些复合材料能够通过基于激光的增材制造在接合过程中形成自润滑膜。研究目的是了解不同数量的磷酸钙加入钛对钛-磷酸钙复合材料力学和生物性能的影响。为了实现这一目标，首先，钛-磷酸钙金属-陶瓷复合材料将使用激光工程净成形处理，使用不同数量的磷酸钙，从钛重量的1%到10%不等。其次，采用伺服液压测试装置，在单轴载荷下测量磷酸钛钙复合材料的力学性能（如拉伸和压缩强度以及弹性模量）。第三，这些复合材料的耐磨性将使用平对平全自动磨损测试装置进行评估。最后，利用人成骨细胞在培养基中培养第3天、第7天和第11天，评估这些复合材料的体外生物学特性。

Metallic biomaterials are typically the choice for wear resistant parts in most biomedical devices towards load-bearing implants. However, concerns are growing related to metal ions in the body that can cause metallosis, and severe tissue and bone damage in some patients. Metallic devices offer greater motion, higher stability and higher than 99 percent reduction in wear debris compared to polymer components; however, use of these metallic implants dropped significantly in recent years primarily due to metal ion release concerns. This Grant Opportunity for Academic Liaison with Industry (GOALI) award supports fundamental research to gain understanding on metal-ceramic composites that can reduce the release of metal ions in human bodies due to in situ formation of self-lubricating films at the contact surface. Results from this research can offer future direction to solve long-standing metal ion release problems in load-bearing implants such as total hip arthroplasty and total knee arthroplasty, which can increase life of implants' for patients of all ages. In load-bearing implants, when two metal surfaces come in contact, there is wear induced damage that releases metal ions inside human bodies. The goal of this project is to minimize release of metal ions from metallic implants inside human bodies using self-lubricating ceramic based tribofilms. These films are formed in situ at the contact surfaces of metal-ceramic composites, and are similar to cartilage between the two hard articulating surfaces in load-bearing implants. The project will generate fundamental knowledge related to processing of metal-ceramic composites capable of forming self-lubricating films during articulation via laser based additive manufacturing. The research objective is to understand the influence of different amounts of calcium phosphates addition to titanium on mechanical and biological properties of titanium-calcium phosphate composites. To achieve this objective, first, titanium-calcium phosphate metal-ceramic composites will be processed using laser engineered net shaping with varying amounts of calcium phosphates, from 1 to 10 weight percent of titanium. Second, mechanical properties (such as tensile and compression strengths, and elastic moduli) of titanium-calcium phosphate composites will be measured under uniaxial loading using servo-hydraulic testing set-up. Third, wear resistance of these composites will be evaluated using flat-on-flat fully automated wear testing set-up. Finally, in vitro biological properties of these composites will be evaluated using human osteoblast cells at day 3, day 7 and day 11 in culture media.