Dresden 2026 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 7: Poster Session I

BP 7.3: Poster

Montag, 9. März 2026, 15:00–17:00, P5

Viscous and Plastic Energy Dissipation Processes of Native Collagen Fibrils in AFM-based Nanoindentation Measurements under Controlled Humidity — •Martin Dehnert, Paul Zech, Mario Zerson, and Robert Magerle — Fakultät für Naturwissenschaften, Technische Universität Chemnitz, Germany

Collagens, lipids, and water are among the major molecular components of connective tissue, yet surprisingly little is known about their interactions in vivo. Here, we use AFM-based nanoindentation experiments to measure the mechanical response of collagen fibrils to deformation under constant strain (relaxation) or constant stress (creep) at different humidity levels and at different deformation speeds. The measured data are evaluated using a power-law analysis, in which the detailed indentation history, including the different indentation velocities, is taken into account. An in-depth analysis reveals that the phenomena of stress relaxation and creep compliance can be described by a time-scaled power law. Furthermore, we show that energy dissipation is primarily caused by plastic deformation during tip indentation and can be quantified with the ductility index. This parameter can also be used for high-resolution imaging of connective tissues. The ductility index provides additional information about the nanomechanical changes in collagen fibrils during development, aging, and disease.

Keywords: Collagen; Nanomechanics; Atomic Force Microscopy; Force-Distance Data; Power Law Rheology