Dresden 2020 – scientific programme
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BP: Fachverband Biologische Physik
BP 20: Poster VIII
BP 20.13: Poster
Tuesday, March 17, 2020, 14:00–16:00, P2/4OG
Nanomechanics of collagen fibrils in native tendon — •Martin Dehnert1, Anke Bernstein2, and Robert Magerle1 — 1Fakultät für Naturwissenschaften, Technische Universität Chemnitz, Germany — 2G.E.R.N. Tissue Replacement, Regeneration & Neogenesis, Department of Orthopedics and Trauma Surgery, Medical Center and Faculty of Medicine, Albert-Ludwigs-University of Freiburg, Germany
We use atomic force microscopy to determine the three-dimensional depth profiles of the local nanomechanical properties of collagen fibrils and their embedding interfibrillar matrix in native (unfixed), hydrated tendon. AFM imaging in air with controlled humidity preserves the tissue’s native water content and allows for high-resolution imaging the assembly of collagen fibrils beneath an approximately 5 to 10-nm-thick layer of the fluid components of the interfibrillar matrix. We collect pointwise force–distance (FD) data from which we construct 3D depth profiles of the local tip–sample interaction forces. We observe diversity in the nanomechanical properties of individual collagen fibrils in their adhesive as well as their repulsive, viscoelastic mechanical response. The contact points between adjacent collagen fibrils are discovered to be twice as stiff as the fibrils. Furthermore, the 3D depth profiles of the tip–sample interaction allow for accurate measurements of the fibrils’ shape within the interfibrillar matrix. With a newly developed force–distance measuring scheme, we separate the viscoelastic deformation from the elastic response of the hydrated collagen. This sheds new light on the role of interfibrillar bonds, the mechanical properties of the interfibrillar matrix, and the biomechanics of native tendon.