Berlin 2012 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 8: Posters: Biopolymers and Biomaterials (with CPP)

BP 8.8: Poster

Montag, 26. März 2012, 17:30–19:30, Poster A

Moderate Swelling of Type I Collagen Fibrils in Humid Air — •Eike-Christian Spitzner, Stephanie Röper, and Robert Magerle — Chemische Physik, TU Chemnitz, D-09107 Chemnitz, Germany

We investigate purified type I collagen extracted from bovine hide. In aqueous solution, triple helices of collagen molecules (tropocollagens) form fibrils driven by hydrogen bonding processes. Single collagen fibrils, deposited on a silicon substrate, were exposed to air with controlled relative humidity (RH). We used in-situ multi-setpoint intermittent contact mode atomic force microscopy for imaging the collagen fibrils at 20% RH, during moderate swelling at 80% RH, as well as dried again at 20% RH. Changes in the mechanical properties of the characteristic D-band structure were observed. At 20% RH, the typical 67 nm spacing appears in the shape of the fibril, whereas at moderate swelling (80% RH) it is visible as a periodic variation of local material properties. Furthermore, in parts of the fibrils, where no D-band structure was observed in the initial state, reconfigurations take place during swelling, which we attribute to a phase transition in the liquid crystalline alignment of the tropocollagen units.