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

金属生物材料通常是大多数生物医疗设备中用于承载植入物的耐磨部件的选择。然而，越来越多的人担心体内的金属离子会导致金属沉积，以及一些患者的严重组织和骨骼损伤。与聚合物部件相比，金属器件具有更大的运动性、更高的稳定性和99%以上的磨屑减少率；然而，近年来这些金属植入物的使用量大幅下降，主要是由于对金属离子释放的担忧。GOALI学术联络机会(GOALI)奖支持基础研究，以了解金属-陶瓷复合材料可以减少由于接触表面原位形成的自润滑膜而在人体内释放的金属离子。本研究结果可为解决全髋关节置换术、全膝关节置换术等负重植入物长期存在的金属离子释放问题提供方向，从而延长各年龄段患者的植入物寿命。在承重植入物中，当两个金属表面接触时，会产生磨损诱导的损伤，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将金属离子从人体内的金属植入物中释放到最低限度。这些膜在金属-陶瓷复合材料的接触面上原位形成，类似于承载种植体中两个硬关节表面之间的软骨。该项目将产生与金属-陶瓷复合材料加工相关的基础知识，该复合材料能够通过基于激光的添加剂制造在关节连接过程中形成自润滑膜。研究目的是了解钛中添加不同量的磷酸钙对钛-磷酸钙复合材料力学性能和生物学性能的影响。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型，其中加入不同数量的磷酸钙，重量百分比从钛的1%到10%不等。其次，利用液压伺服试验台测量钛钙磷酸盐复合材料在单轴加载下的力学性能(如拉伸强度、压缩强度和弹性模量)。第三，这些复合材料的耐磨性将使用平板对平板全自动磨损试验台进行评估。最后，在培养的第3天、第7天和第11天，使用人成骨细胞对这些复合材料的体外生物学特性进行评估。

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.