Preparation strategies for phosphate-based mineral biomaterials

Minerals with different particle size and morphology were prepared, and the effects of different preparation methods were analyzed. The minerals, fluoroapatites, were synthesized from CaCl₂, Na₂HPO₄ and KF by precipitation in aqueous solution, precipitation in microemulsions and by a biomimetic synthesis in a gelatine matrix. Several characterization methods were used. The effects of varying the synthesis conditions on the size and the morphology of the powder were analyzed with scanning and transmission electron microscopy. The crystallinity and phase purity were determined by X-ray diffraction and Fourier transform IR spectroscopy. The particle sizes were measured by transmission electron microscopy and dynamic light scattering. Precipitation from aqueous solution yielded particles with rodshaped and amorphous morphology, whereas precipitation from a microemulsion resulted in rod-shaped crystals and after tempering in amorphous shapes. Spherical particles were obtained by biomimetical synthesis. The smallest size of the primary particles was about 15 nm and the largest was about 200 μm.