title: The role of fiber-matrix interactions in a nonlinear fiber-reinforced strain energy model of tendon.
abstract: The objective of this study was to develop a nonlinear and anisotropic three-dimensional mathematical model of tendon behavior in which the structural components of fibers, matrix, and fiber-matrix interactions are explicitly incorporated and to use this model to infer the contributions of these structures to tendon mechanical behavior. We hypothesized that this model would show that: (i) tendon mechanical behavior is not solely governed by the isotropic matrix and fiber stretch, but is also influenced by fiber-matrix interactions; and (ii) shear fiber-matrix interaction terms will better describe tendon mechanical behavior than bulk fiber-matrix interaction terms. Model versions that did and did not include fiber-matrix interaction terms were applied to experimental tendon stress-strain data in longitudinal and transverse orientations, and the R2 goodness-of-fit was evaluated. This study showed that models that included fiber-matrix interaction terms improved the fit to longitudinal data (R2(toe) = 0.88, R2(Lin) = 0.94) over models that only included isotropic matrix and fiber stretch terms (R2(Toe) = 0.36, R2(Lin) = 0.84). Shear fiber-matrix interaction terms proved to be responsible for the best fit to data and to contribute to stress-strain nonlinearity. The mathematical model of tendon behavior developed in this study showed that fiber-matrix interactions are an important contributor to tendon behavior The more complete characterization of mechanical behavior afforded by this mathematical model can lead to an improved understanding of structure-function relationships in soft tissues and, ultimately, to the development of tissue-engineered therapies for injury or degeneration.
authors.affiliation: Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, 424 Stemmler Hall, Philadelphia, PA 19104-6081, USA.
authors.forename: Heather Anne L
authors.initials: HA
authors.lastname: Guerin
authors.forename: Dawn M
authors.initials: DM
authors.lastname: Elliott
mesh_terms: D000818:Animals; D016880:Anisotropy; D003198:Computer Simulation; D004548:Elasticity; D004735:Energy Transfer / Q000502:physiology; D005109:Extracellular Matrix / Q000502:physiology*; D024022:Fibrillar Collagens / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D017711:Nonlinear Dynamics; D013314:Stress, Mechanical; D013710:Tendons / Q000502:physiology*; D013718:Tensile Strength / Q000502:physiology
chemical_list: D024022:Fibrillar Collagens