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BP: Fachverband Biologische Physik

BP 7: Poster I

BP 7.21: Poster

Montag, 23. März 2009, 17:45–20:00, P3

Atomic force microscopy of collagen — •Nadine Drechsel, Stephanie Röper, Christian Dietz, and Robert Magerle — Chemische Physik, TU Chemnitz, D-09107 Chemnitz

Type I collagen is a protein material which is a basic constituent of all vertebrates. It can be found in various types of biological tissue, e.g., dermal tissue and bone tissue. We investigate purified collagen isolated from bovine hide which is adsorbed on a mica substrate in buffer solution (L-Glycin/KCl, pH 9,2). Collagen in a buffer solution, in moist air and in the dried state is studied with atomic force microscopy (AFM). For measurements in liquid, the sample is rinsed and imaged in buffer solution, for measurements in air collagen is transferred from the buffer solution to a cleaned mica substrate and subsequently either dried or imaged in moist air. In both cases we find the typical D-band with a repeat distance of 67 nm. We also performed bimodal AFM measurements; the second flexural eigenmode of the cantilever was used for phase imaging while the amplitude of the first eigenmode was used as feedback signal. On a dried specimen we measured the dissipated energy between AFM tip and a collagen fibril. The results on the collagen fibril prepared from bovine hide are compared with measurements on native cortical human bone.