Collaborative Research: Micro- and Nano-Scale Characterization and Modeling of Bone Tissue

本课题的研究目标是表征骨组织的微尺度力学行为。骨是一种具有层次结构的材料，其组织水平的大小从纳米到毫米不等。 成分和微观结构随年龄和疾病而变化。迄今为止，关于骨的机械表征的大部分工作集中在宏观尺度特性（例如毫米-厘米尺度）上，并且对构成骨的构建块的矿化组织的内在机械特性知之甚少。该研究项目通过应用微机械加工技术来分离特定的微结构组件，然后在简单的压缩中进行测试，来表征这些特性。 微柱的尺寸从数百纳米到几十微米的飞秒激光烧蚀和聚焦离子束微加工技术，然后使用修改后的纳米压痕测试。力学测试的结果将用于开发骨折的微观力学模型。该研究项目的结果将建立一种实验方法，用于对机械功能对肌肉骨骼健康至关重要的组织进行微观和纳米级机械表征。这些方法将补充现有的技术，用于研究年龄和疾病相关的变化，骨成分和微观结构，通过提供一种方法来确定这些变化如何影响骨的机械性能在相同的长度尺度的变化本身。该研究项目还将侧重于年轻科学家和工程师的专业准备。本科生和研究生将直接参与研究活动。研究活动还将纳入课程和外联活动，使大学预科和非技术学生接触材料科学和工程领域。

The research objective of this project is to characterize the microscale mechanical behavior of bone tissue. Bone is a hierarchically structured material with organization levels ranging in size from nanometers to millimeters. Composition and microstructure vary with age and disease. The majority of work to date on mechanical characterization of bone has focused on macroscale properties (e.g. millimeter-centimeter scale), and little is known about the intrinsic mechanical properties of the mineralized tissue that constitutes the building block of bones. This research project characterizes these properties by applying micromachining techniques to isolate specific microstructural components, which are then tested in simple compression. Micropillars ranging in size from hundreds of nanometers to tens of microns are produced by femtosecond laser ablation and focused ion beam micromachining techniques and then tested using a modified nanoindenter. The results of the mechanical tests will be used to develop micromechanical models of bone fracture. The results of this research project will establish an experimental approach for micro- and nanoscale mechanical characterization of a tissue whose mechanical function is critical for musculoskeletal health. These methods will complement existing techniques for studying age- and disease-related changes in bone composition and microstructure by providing a means of determining how these changes affect bone mechanical properties at the same length scale as the changes themselves. This research project will also focus on professional preparation of young scientists and engineers. Undergraduate and graduate students will participate directly in the research activities. The research activities will also be incorporated in courses and outreach events that expose pre-college and non-technical students to the field of materials science and engineering.