Regensburg 2019 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 7: Bioimaging and biospectroscopy II

BP 7.4: Vortrag

Dienstag, 2. April 2019, 10:15–10:30, H4

3D depth profiling the interaction between an AFM tip and hydrated, native collagen fibrils in sheep tendon — •Martin Dehnert¹, Diana Voigt¹, Anke Bernstein², and Robert Magerle¹ — ¹Fakultät für Naturwissenschaften, TU Chemnitz, Germany — ²Department Chirurgie, Universitätsklinikum Freiburg, Germany

Imaging with atomic force microscopy (AFM) the structure and the viscoelastic properties of hydrated, native tissue on the nanometer scale is challenging since the AFM tip interacts with a soft, compliant, partially fluid, and adhesive specimen. Furthermore, the tissue’s water content needs to be maintained during AFM imaging. Here we study collagen fibrils in hydrated, native sheep tendon with AFM-based measurements of force–distance (FD) curves and amplitude–phase–distance (APD) curves. From this data, we reconstruct three-dimensional (3D) depth profiles of the tip–sample interaction. This allows for distinguishing the viscoelastic response of individual collagen fibrils within the tendon from the attractive capillary forces between the AFM tip and the viscous interfibrillar matrix. The 3D depth profiles reveal a large diversity in nanomechanical properties among individual collagen fibrils in both their viscoelastic response and the attractive tip–sample interaction. Furthermore, we obtain information about the local mechanical response of the interfibrillar matrix. We expect that this comprehensive nanomechanical characterization will contribute to a better understanding of tendon biomechanics on the nanometer scale.