title: Biomechanical properties of murine meniscus surface via AFM-based nanoindentation.
abstract: This study aimed to quantify the biomechanical properties of murine meniscus surface. Atomic force microscopy (AFM)-based nanoindentation was performed on the central region, proximal side of menisci from 6- to 24-week old male C57BL/6 mice using microspherical tips (Rtip≈5µm) in PBS. A unique, linear correlation between indentation depth, D, and response force, F, was found on menisci from all age groups. This non-Hertzian behavior is likely due to the dominance of tensile resistance by the collagen fibril bundles on meniscus surface that are mostly aligned along the circumferential direction. The indentation resistance was calculated as both the effective modulus, Eind, via the isotropic Hertz model, and the effective stiffness, Sind = dF/dD. Values of Sind and Eind were found to depend on indentation rate, suggesting the existence of poro-viscoelasticity. These values do not significantly vary with anatomical sites, lateral versus medial compartments, or mouse age. In addition, Eind of meniscus surface (e.g., 6.1±0.8MPa for 12 weeks of age, mean±SEM, n=13) was found to be significantly higher than those of meniscus surfaces in other species, and of murine articular cartilage surface (1.4±0.1MPa, n=6). In summary, these results provided the first direct mechanical knowledge of murine knee meniscus tissues. We expect this understanding to serve as a mechanics-based benchmark for further probing the developmental biology and osteoarthritis symptoms of meniscus in various murine models.
authors: School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA 19104, United States.
authors: Qing
authors: Q
authors: Li
authors: School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA 19104, United States.
authors: Basak
authors: B
authors: Doyran
authors: Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, United States.
authors: Laura W
authors: LW
authors: Gamer
authors: Department of Mechanical Engineering, University of Delaware, Newark, DE 19716, United States.
authors: X Lucas
authors: XL
authors: Lu
authors: Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA 19104, United States.
authors: Ling
authors: L
authors: Qin
authors: Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
authors: Christine
authors: C
authors: Ortiz
authors: Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Mechanical Engineering Massachusetts Institute of Technology, Cambridge, MA 02139, United States.
authors: Alan J
authors: AJ
authors: Grodzinsky
authors: Department of Developmental Biology, Harvard School of Dental Medicine, Boston, MA 02115, United States.
authors: Vicki
authors: V
authors: Rosen
authors: School of Biomedical Engineering, Science, and Health Systems, Drexel University, Philadelphia, PA 19104, United States. Electronic address: lh535@drexel.edu.
authors: Lin
authors: L
authors: Han
mesh_terms: D000818:Animals; D016880:Anisotropy; D001696:Biomechanical Phenomena; D002358:Cartilage, Articular / Q000473:pathology / Q000503:physiopathology*; D004195:Disease Models, Animal; D055119:Elastic Modulus; D008297:Male; D008592:Menisci, Tibial / Q000473:pathology / Q000503:physiopathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018625:Microscopy, Atomic Force / Q000379:methods; D008855:Microscopy, Electron, Scanning; D020370:Osteoarthritis, Knee / Q000473:pathology; D013499:Surface Properties; D014783:Viscosity
keywords: Anisotropy; Atomic force microscopy; Meniscus; Mouse models; Nanoindentation