Dresden 2009 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 7: Poster I
BP 7.24: Poster
Montag, 23. März 2009, 17:45–20:00, P3
Imaging human bone with bimodal scanning force microscopy — •Stephanie Röper1, Nadine Drechsel1, Christian Dietz1, Anke Bernstein2, and Robert Magerle1 — 1Chemische Physik, TU Chemnitz, D-09107 Chemnitz — 2Experimentelle Orthopädie, Martin-Luther-Universität Halle-Wittenberg, D-06097 Halle/Saale
Biological materials such as bone and teeth are nanocomposites of a soft organic matrix (type I collagen) that is reinforced by a stiff inorganic component (hydroxylapatite). Our study is focused on cortical human bone. The specimen surface was first mechanically grinded and polished, then 10 s etched with formic acid and finally flushed with methanol to stop the etching process. With optical microscopy and tapping mode scanning force microscopy (TM-SFM) a spot on the specimen was chosen for detailed investigation which displays a lamellar structure in the vicinity of a Haversian canal. TM-SFM images measured in air show collagen fibrils with typical D-bands with 67 nm periodicity. For bimodal TM-SFM the second flexural eigenmode of the cantilever was used for phase imaging while the amplitude of the first eigenmode was used as feedback signal. The second eigenmode phase image revealed an enhanced contrast compared to that of the first eigenmode. In addition we measured the energy dissipated between tip and specimen along a collagen fibril. The results obtained on native human bone were compared with measurements on collagen fibrils prepared from purified collagen isolated from bovine hide.