Porous Nitinol for Load Bearing Implants Using Rapid Prototyping

该奖项的研究目标是应用激光工程净成形(LENS(TM))，这是一种基于快速原型的先进制造技术，以制造镍醇的多孔结构。将测量不同孔隙率的NiInol结构的物理、机械和生物性能。在承载植入物中使用多孔材料可以减少由于孔洞造成的刚度不匹配，并解决长期存在的应力遮挡等问题。设计的孔隙度还将实现稳定的长期生物固定，因为骨组织从表面到内部都会生长到相互连接的孔洞中。镍钛是一种形状记忆合金，表现出高达8%的可恢复应变，类似于观察到约1%可恢复应变的骨骼。镍钛合金和骨的这种相似的变形行为有助于负重植入物在体内的加载-卸载条件下具有相同的性能，从而确保了出色的生物力学兼容性。镍钛醇也是一种生物兼容材料，目前正用于几种生物医学设备。该方法是使用柔性透镜(TM)参数来制造具有设计的宏孔和微孔结构的多孔镍镍植入物，以达到预期的性能。然后，将建立Lens(TM)制造的镍钛合金的机械性能和生物性能的工艺-性能关系。如果成功，该计划的结果将为简单和复杂形状植入物的设计和制造提供灵活性，采用新型形状记忆合金镍钛合金，可以匹配骨骼的机械性能。新型多孔植入物可能会使承载植入物的寿命增加一倍或三倍。作为一种计算机辅助、基于设计的过程，LENS(TM)还可用于根据计算机断层扫描和磁共振成像数据制造针对患者的植入物。该项目还将教育和培训机械工程、材料科学和工程以及生物工程方面的研究生和本科生。

The research objective of this award is to apply Laser Engineered Net Shaping (LENS(TM)), a rapid prototyping based advanced manufacturing technology, to create porous structures of nitinol. The physical, mechanical and biological properties of nitinol structures of varying porosity will be measured. Use of porous materials in load bearing implants can reduce the stiffness mismatches due to porosity and solve long-standing problems like stress shielding. Designed porosity will also achieve stable long-term biological fixation due to bone-tissue in-growth into interconnected porosity from the surface to the inside. Nitinol is a shape memory alloy that shows up to 8 percent recoverable strain, similar to bone in which about 1 percent recoverable strain is observed. This similarity in the deformation behavior between Nitinol and bone contribute to identical performance of load bearing implants under loading-unloading conditions in the body ensuring excellent biomechanical compatibility. Nitinol is also a biocompatible material and currently in use in several biomedical devices. The approach is to use flexible LENS(TM) parameters to fabricate porous nitinol implants with designed macro and micro porous structures to achieve desired performance. Process-property relationships, for both mechanical and biological properties, for LENS(TM) fabricated nitinol will then be established.If successful, results from this program will offer design and manufacturing flexibility of simple and complex shaped implants with novel shape memory alloy, nitinol, that can match mechanical properties of bone. Novel porous implants can potentially double or triple the lifetime of load bearing implants. Being a computer-aided, design-based process, LENS(TM) can also be used to fabricate patient-specific implants from computed tomography and magnetic resonance imaging data. The project will also educate and train graduate and undergraduate students in mechanical engineering, materials science and engineering and bioengineering.