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

Lafayette College, Easton PA

Investigators

Abstract

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.