Dresden 2017 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 14: Poster: Bioinspired Functional Materials

CPP 14.2: Poster

Monday, March 20, 2017, 18:30–21:00, P1C

3D depth profiles of tip--sample interaction on type I collagen fibrils in humid air — •Robert Magerle¹, Manuel R. Uhlig¹, Diana Voigt¹, Martin Dehnert¹, and Anke Bernstein² — ¹Fakultät für Naturwissenschaften, Technische Universität Chemnitz — ²Orthopädie und Traumatologie, Universitätsklinikum Freiburg

The water content and intermolecular crosslinks between collagen fibrils are important factors that determine the mechanical properties of type I collagen fibrils. With atomic force microscopy (AFM) we study reconstituted type I collagen fibrils (without crosslinks) and native fibrils from sheep tendon (with crosslinks). The water content in the fibrils is controlled via the relative humidity of air in the AFM. We measure force--distance (FD) curves and amplitude--phase--distance (APD) curves and reconstruct from this data three-dimensional (3D) depth profiles of the tip--sample interaction. This reveals the contributions of the attractive capillary interaction, the adhesive interaction as well as the repulsive viscoelastic response of the hydrated collagen fibrils. Furthermore, the 3D depth profiles of the tip--sample interaction allow for accurate measurements of the fibrils' shape and the fibrils' swelling behavior with increasing water content. We compare this with the related changes in the fibrils' elastic modulus and discuss the role of water content and intermolecular crosslinks in collagen fibrils.