Regensburg 2007 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 14: Biological Systems
CPP 14.5: Vortrag
Dienstag, 27. März 2007, 11:15–11:30, H47
Mineral phase distribution in biological composite material of a crustacean model organism — •Sabine Hild1, Othmar Marti2, and Andreas Ziegler1 — 1Central Facility for Electron Microscopy; University of Ulm, Albert-Einstein-Allee 11, 89069 Ulm — 2Experimental Physics; University of Ulm, Albert-Einstein-Allee 11, 89069 Ulm
Mineralized biological composites have attracted increasing interest because of their outstanding mechanical properties that are well adapted to their function. The mineralized exoskeleton (cuticle) of crustaceans is an excellent model in this field. To learn more about the properties, function and formation of biomaterials, we studied the spatial distribution of minerals, elements, and organic compounds within the cuticle of the terrestrial isopod Porcellio scaber on the sub-micrometer scale using confocal mciro-Raman microscopy, REM and SFM. In cross-sections of the cuticle we found calcite and amorphous calcium carbonate (ACC) as the main biominerals. For the first time, we show that minerals are arranged in distinct layers. Calcite is restricted to the outer area of the cuticle, whereas ACC is localized in the middle having only little overlap with the calcite layer. Since the cuticle is subjected to periodic molting it is periodically decalcified and shed. A new larger cuticle, synthesized before shedding, is mineralized after every molt. These processes cause spatial and temporal variations of the mineral distribution. We show that the protective outer calcite layer is shed away during each molt, while ACC is recycled to quickly re-establish the protective calcite layer in the new cuticle.