Pulsed water jet treatments of the surfaces of metal alloys for biomedical applications

每年，超过10万加拿大人需要进行膝盖或髋关节置换。目前的技术使用钛合金 将植入物固定到骨上，但界面出现了问题，可以用脉冲水射流解决 (PWJ)由VLN Advanced Technologies Inc.开发的技术。合金的表面通常 用氧化铝颗粒喷砂粗化，以促进设备上的细胞生长。然而， 颗粒被嵌入到钛表面。一旦进入患者体内，微粒就会被排出体外。 并导致周围组织中的细胞死亡和种植体的松动，这是导致翻修的主要原因 做手术。相比之下，脉冲水射流使用超声波将连续的水流分解成一系列高强度的 速度脉冲，通过循环加载目标而产生机械侵蚀，而不嵌入任何异物 材料。 我们将与VLN一起开发一种具有成本效益的方法，使用PWJ来消除砂石喷砂的需要。 并创造出更好的生物相容性表面。为了使钛种植体在骨中有良好的粘附性，医疗部门 植入物需要具有跨越微米到纳米尺度的表面特征，以便 模仿周围的生物纹理。自然分成两个相的冶金合金 组件使用多长度比例特征在其颗粒结构中创建图案，这些特征可以模仿 生物系统。外科钛合金分为更强和更弱的成分。我们将设计 用脉冲水射流机械地侵蚀掉较弱的成分并留下 粗糙的表面，具有微米和纳米尺度的特征。物理结构、化学和 处理过的表面的机械性能将用达尔豪西大学的一套工具进行表征 确定最佳的PWJ参数。最后，我们将探索设计表面的可能性。 达尔豪西目前正在开发通过改变钛合金的晶格结构来改善钛合金的表面形貌。

Each year, over 100,000 Canadians require knee or hip replacement. Current technology uses a titanium alloy to attach the implant to the bone, but problems arise at the interface that could be solved with pulsed water jet (PWJ) technology developed at VLN Advanced Technologies Inc. The surface of the alloy is typically roughened by grit blasting with aluminum oxide particles to promote cell growth on the device. However, the particles get imbedded into the titanium surface. Once inside the patient, the particles can become dislodged and lead to cell death in the surrounding tissue and the loosening of the implant, the leading cause for revision surgery. In contrast, pulsed water jets use ultrasound to break a continuous water stream into a series of high speed pulses that create mechanical erosion by cyclic loading of the target without embedding any foreign material. Together with VLN, we will develop a cost effective way of using PWJs to eliminate the need for grit blasting and create a better biocompatible surface. For good adhesion of a titanium implant in bone, the medical implant needs to have surface features with sizes that span the micron scale down to the nano-scale in order to mimic the surrounding biological textures. Metallurgical alloys that naturally phase separate into two components create patterns in their grain structure with multi-length scale features that can imitate those of biological systems. Surgical titanium alloy separates in to a stronger and weaker component. We will design the techniques to mechanically etch away the weaker component with pulsed water jets and leave behind a rough surface with features on the micron- and nano-length scales. The physical structure, chemistry and mechanical properties of the treated surfaces will be characterized with a suite of tools at Dalhousie University to identify the optimal PWJ parameters. Finally we will explore the possibility of engineering the surface morphology by modifying the grain structure in titanium alloys currently being developed at Dalhousie.