Dresden 2006 – scientific programme

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CPP: Chemische Physik und Polymerphysik

CPP 4: New Experimental Techniques

CPP 4.11: Talk

Monday, March 27, 2006, 17:00–17:15, ZEU Lich

Confocal micro-Raman spectroscopy: A tool to discriminate calcified biominerals in land living crustaceans — •Sabine Hild and Andreas Ziegler — Central Facility for Electron Microscopy; University of Ulm, Albert-Einstein-Allee 11, 89081 Ulm

Land living crustaceans, like Porcellio scaber (Isopoda), have the ability to elaborate various types of calcified biominerals e.g. calcium phosphate, calcite, and amorphous calcium carbonate (ACC). Crystalline minerals are located mainly in the mineralized exoskeleton (cuticle) of the animals. Amorphous minerals, like ACC, which is thought to be a precurser for crystalline CaCO3, occur primarily in transient reservoirs for calcium. To get information about the morphology of the inorganic phase and their spatial distribution imaging techniques like REM and SFM are suitable. However, the various modifications of the biominerals cannot be discriminated by these techniques. Scanning confocal *-Raman spectroscopy (SCRS) enables to investigate the chemical composition of materials with a high resolution. In this study Raman spectral imaging in combination with SFM have been used to characterize and localize amorphous and crystalline minerals in a calcified tissue of P. scaber. First SCRS experiments reveal both crystalline and amorphous CaCO3 within the cuticle. Our model organism develops also transient reservoirs, which are fully X-ray amorphous. The reservoirs contain only ACC embedded in an organic matrix, which is proposed to stabilize the ACC. Additionally detected phosphate derivates suggests that they may also influence the stabilization of amorphous calcium carbonate.