[Raman spectrometry applied to calcified tissue and calcium-phosphorus biomaterials]

The rigid part of the human body consists essentially of carbonated apatite (calcium phosphate). Biologists don't have any tools to study this "mineral" phase, though its origin is organic. A new approach of some compounds like enamel or bone is obtained with the Raman micro-characterisation by a very fine analysis of chemical bonds in a micrometric scale. This method allows the characterisation, the analysis and the dosage of ions, like carbonate, acid phosphates, proteins and fatty acids. The identification of other organic or mineral compounds (e.g. calcium carbonate, calcium oxide, substitutant ions...) is also possible. The Raman microspectrometry can also be used to study the chemical and physical properties of biomaterials and their evolution after implantation in a dental or bone site. On synthetical calcium phosphate, beta-TCP, brushite and hydroxyapatite can be distinguished and the impurities found in plasma spray deposits can be measured. The detection of alpha-, beta-, or gamma-pyrophosphates could be obtained in some commercial beta-TCP. The Raman microspectrometry is the only non-destructive method which allows the identification of the chemical bonds in a micrometric scale and gives the "fingerprint" of the studied component.