Bio-tribo-corrosion resistant 3D Printed Composites for Load-bearing Implants

在负重植入物中，全髋关节置换术可能是最临床的。 成功的干预。CoCrMo合金是一种耐磨材料，通常用于 临屋区的股骨头。在体内，由于碎片的产生，THAs的寿命往往会缩短，而Co 和铬金属离子从模块结中释放。耳轴锥度腐蚀的治理 今天，CoCrMo磁头和Ti6Al4V磁杆的性能仍然是一个严峻的挑战。锥形腐蚀 主要是由于机械辅助缝隙腐蚀(MACC)以及微动 和电偶腐蚀，并导致不良局部组织反应(ALTR)，一种免疫- 钴、铬离子升高引起的生物反应。ALTR对 导致植入物失败，从而导致早期翻修手术。钴和铬离子可以 还会引起其他症状，如耳聋、失明和间质细胞损伤，从而导致 肾功能受损。我们的应用重点是自我润滑和自我修复 磷酸钙(CaP)增强钛或钴铬钼合金最大限度地减少生物摩擦腐蚀 如耳轴在临屋区模块锥形联锁中的应用。CoCrMo-帽复合材料将 与纯CoCrMo合金相比，旨在最大限度地减少钴和铬离子的释放；而钛合金- CAP复合材料的设计将完全消除由于以下原因而释放的钴和铬离子 腐蚀或磨损退化。 这项拟议的研究的目的是检验我们的中心假设，即基于帽的固体 钛或钴铬钼合金中的润滑剂将在接触表面形成一层原位薄膜，以减少生物污染 抗摩擦腐蚀，减少金属离子释放。理由是，一旦我们理解了 摩擦膜的形成机理及其对生物摩擦腐蚀的影响，可以设计 体内金属离子释放可能性降低的植入物。我们的初步数据显示现场 Ti6Al4V或CoCrMo合金在体外生物摩擦过程中形成带帽强化的摩擦膜 腐蚀研究。摩擦膜的存在降低了磨损引起的损伤，并将金属离子降至最低 体外释放。我们对提议的计划有三个具体目标--(1)理解 高强增强钛合金基复合材料的摩擦磨损机理及摩擦膜的形成， 并测定它们的体外生物学反应；(2)了解摩擦腐蚀机理和 CAP增强CoCrMo复合材料中摩擦膜的形成及其体外生物测定 响应，以及(3)测量添加CAP的钛或CoCrMo合金的体内生物学性能。

Among load-bearing implants, total hip arthroplasty (THA) is probably the most clinically successful intervention. CoCrMo alloy, a wear resistant material of choice, is typically used in femoral heads for THAs. In vivo life of THAs are often reduced due to debris generation, and Co and Cr metal ion release from modular junctions. Management of taper corrosion from trunnions of CoCrMo head and Ti6Al4V stems remain a serious challenge today. Taper corrosion happens primarily due to mechanically assisted crevice corrosion (MACC) along with fretting and galvanic corrosion, and leads to adverse local tissue reactions (ALTR), an immune- mediated biological reaction due to elevated Co and Cr ions. ALTR has profound influence on bone, leading to implant failure, which can result in early revision surgery. Co and Cr ions can also cause other symptoms such as deafness, blindness, and interstitial cell damage resulting in impaired renal functioning. Our application is focused on self-lubricating and self-healing calcium phosphate (CaP) reinforced Ti- or CoCrMo-alloys to minimize bio-tribocorrosion in applications such as trunnions in modular taper interlocks in THAs. CoCrMo-CaP composite will be designed to minimize Co and Cr ion release compared to pure CoCrMo alloy; while Ti alloy- CaP composites will be designed to completely eliminate the release of Co and Cr ions due to corrosion or wear degradation. The objective of this proposed research is to test our central hypothesis that CaP based solid lubricants in Ti or CoCrMo alloys will form an in situ film at the contact surface to minimize bio- tribo-corrosion and reduce metal ion release. The rationale is that once we understand the mechanisms of tribofilm formation and its influence on bio-tribo-corrosion, we can design implants with reduced metal ion release possibility in vivo. Our preliminary data show in situ tribofilm formation with CaP reinforcement in Ti6Al4V or CoCrMo alloys during in vitro bio-tribo- corrosion studies. Presence of tribofilm lowered wear induced damage and minimized metal ion release in vitro. We have three Specific Aims for the proposed program – (1) to understand tribocorrosion mechanism and tribofilm formation in CaP reinforced Ti-alloy matrix composites, and measure their in vitro biological response; (2) to understand tribocorrosion mechanism and tribofilm formation in CaP reinforced CoCrMo composites, and measure their in vitro biological response, and (3) to measure in vivo biological properties of CaP added Ti or CoCrMo alloys.