ERI: Mechanical Characterization of the Interfascicular Matrix of Patellar Tendon in Shear and Transverse Tension

韧带和肌腱是连接骨骼和肌肉并在这些组织之间传递力的肌肉骨骼组织。这些组织有助于稳定肌肉骨骼系统，防止损伤过度伸展关节。尽管这在身体功能中起着关键作用，但预测韧带和肌腱如何变形和失效的能力有限。如果没有这种预测能力，研究人员使用计算工具更好地了解损伤和肌肉骨骼损伤的治疗的能力是有限的。这项由工程研究启动奖(ERI)支持的研究的目标是从事基础研究，通过检查构成组织的两个组成部分：束间基质(IFM)和肌束的变形，更好地了解韧带和肌腱是如何变形和失效的。先前关于韧带和肌腱力学的工作将IFM和肌束均质化为一种物质。然而，最近的工作表明，在分析整个组织的变形和破坏时，这两个区域不能均质。使用力学试验的立体数字图像相关(DIC)分析结合逆有限元分析来表征IFM和束状物的力学性能。为了在测试过程中最大限度地加载IFM，将以横向拉伸和剪切的方式加载髌腱样本。将使用配备微距镜头的立体声DIC装置跟踪变形，该装置可实现10-μm的空间分辨率，可区分IFM和分束区域。然后，将使用逆有限元方法分析实验变形场，以提取IFM和束状物的力学特性。将使用空间分辨率为10μm的摄影测量装置生成机械表征过程中使用的组织样本的3D模型。这项研究将首次生成一组空间上不同的变形数据和区分IFM和束状区的材料属性。为了促进更广泛地参与工程学，将与STEM的女工程师协会和拉斐特学院接受过包容性指导做法培训的工程学教员一起组织一次招聘会议。通过与老佛爷教学中心合作建立一个正式的导师评估计划，老佛爷的研究导师制将得到改善。将举办一次科学写作研讨会，使本科生研究人员能够在学术研究论文中交流他们的发现。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Ligaments and tendons are musculoskeletal tissues that connect bones and muscles and transmit forces between these tissues. These tissues help to stabilize the musculoskeletal system and prevent injury from overextending a joint. Despite this critical role in bodily function, there is a limited ability to predict how ligaments and tendons deform and fail. Without this predictive ability, researchers are limited in their capacity to use computational tools to better understand the injury and treatment of musculoskeletal injuries. The goal of the research supported by this Engineering Research Initiation (ERI) award is to engage in fundamental research to better understand how ligaments and tendons deform and fail by examining deformations of the two components that make up the tissue: the interfascicular matrix (IFM) and the fascicles. Prior work on ligament and tendon mechanics homogenizes the IFM and fascicles into one substance. However, recent work has demonstrated that these two regions cannot be homogenized when analyzing whole tissue deformation and failure. The mechanical properties of the IFM and fascicles will be characterized using a stereo digital image correlation (DIC) analysis of mechanical tests combined with inverse finite element analysis. To maximally load the IFM during testing, patellar tendon samples will be loaded in transverse tension and shear. Deformations will be tracked using a stereo DIC setup equipped with macro lenses, which enable a 10-μm spatial resolution that can differentiate between the IFM and fascicle regions. The experimental deformation fields will then be analyzed using an inverse finite element scheme to extract the mechanical properties of the IFM and fascicles. The 3D models of the tissue samples used during mechanical characterization will be generated using a photogrammetry setup that has a spatial resolution of 10 μm. This research will be the first to generate a set of spatially heterogeneous deformation data and material properties that differentiate between the IFM and fascicle regions. To promote broader participation in engineering, a recruitment session will be organized with the Society of Women Engineers, Out in STEM, and engineering faculty members at Lafayette College who have received training on inclusive mentorship practices. Research mentorship at Lafayette will be improved by creating a formal mentorship evaluation program in partnership with Lafayette’s teaching center. A scientific writing workshop will be conducted to enable undergraduate researchers to communicate their findings in academic research papers.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.