Collaborative Research: Aging and Disease Effects on Viscous Energy Dissipation of Bone as Characterized by Nanoindentation

该奖项的研究目标是将一种新兴的动态纳米压痕方法应用于骨骼，以便在微米长度尺度上量化组织粘弹性行为中与年龄和疾病相关的变化，从而与其断裂行为相关联。 骨的主要成分的组织本质上是分层的，因此，每个层次都有助于骨抵抗骨折的能力。 将使用来自年轻和老年人供体、啮齿动物疾病模型和特性已被体外改变的骨的皮质骨，在椎板水平和骨组织结构水平进行动态纳米压痕和R曲线测试。 此外，将测量骨的组成特征，以评估其对粘弹性和断裂韧性的相对贡献。这项工作有可能证明，衰老和某些疾病，如糖尿病，导致骨耗散较少的能量，通过抑制粘性机制在组织水平，从而有助于在骨的断裂阻力的整体下降。 此外，该研究将为研究生物组织的小尺度变形行为引入一套新的工具。 该项目产生的科学知识将加强该领域的努力，开发骨质量的分层模型，并确定预防骨折的新治疗目标。 该项目汇集了一个工程和医学院的多学科团队，为材料科学和生物医学工程研究人员的专业知识提供了交叉交流的机会。 该教育计划的重点是为工程师开辟途径，使其对医学研究产生影响，并使生物医学研究人员受益于物理科学中开发的实验方法。

The research objective of this award is to apply an emerging dynamic nanoindentation method to bone so that age- and disease-related changes in the viscoelastic behavior of the tissue can be quantified at the micron length scale for correlation with its fracture behavior. The organization of the primary constituents of bone is inherently hierarchical, and as such, each level contributes to the ability of bone to resist fracture. Dynamic nanoindentation and R-curve testing will be conducted at the level of the lamellae and at the level of the osteonal structure using cortical bone from young and old human donors, rodent models of disease, and bone whose properties have been altered ex vivo. In addition, the compositional characteristics of the bone will be measured to assess their relative contribution to the viscoelastic properties and fracture toughness.This work has the potential to demonstrate that aging and certain diseases such as diabetes cause bone to dissipate less energy by suppression of viscous mechanisms at the tissue-level, thereby contributing to an overall reduction in the fracture resistance of bone. Moreover, the research will introduce a new set of tools for investigating the small-scale deformation behavior of biological tissues. The scientific knowledge generated from this program will enhance efforts in the field to develop hierarchical models of bone quality and to identify new therapeutic targets for fracture prevention. The project brings together an engineering and medical school multidisciplinary team, providing the opportunity for cross-fertilization of expertise from researchers in materials science and biomedical engineering. The educational plan focuses on opening pathways for engineers to make an impact on medical research and biomedical researchers to benefit from experimental approaches developed in the physical sciences.