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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 12: Poster 1

CPP 12.6: Poster

Montag, 5. September 2022, 18:00–20:00, P1

Mapping nanomechanics and energy dissipation of collagen fibrils in tendon — •Martin Dehnert, Paul Zech, Mario Zerson, and Robert Magerle — Fakultät für Naturwissenschaften, Technische Universität Chemnitz, Germany

We study the nanomechanical properties of hydrated collagen fibrils with AFM-based nanoindentation measurements. Force–distance (FD) data measured with tip velocities < 1  µm/s display a rate-independent hysteresis with return point memory depending on only one return point. With different indentation protocols, we show that stress relaxation and creep do not influence the time evolution of the FD data. The main cause of hysteresis is the elastoplastic deformation of collagen fibrils above the glass transition. We explore the variations of these nanomechanical properties in sets of unfixed hydrated collagen fibrils isolated from native chicken Achilles tendon and compare them with collagen fibrils embedded in the natural tendon. AFM imaging in the air with controlled humidity preserves the tissue’s native water content and allows for high-resolution imaging and nanoindentation measurements. This sheds new light on the role of interfibrillar bonds, the mechanical properties of the interfibrillar matrix, and the biomechanics of native tendon.