fluorapatite and ammonium-fluoride

Fluorapatite (FA)-collagen composites were synthesized via a biomimetic coprecipitation method in order to improve the structural stability and cellular responses. Different amounts of ammonium fluoride (NH4F), acting as a fluorine source for FA, were added to the precipitation of the composites. The precipitated composites were freeze-dried and isostatically pressed in a dense body. The added fluorine was incorporated nearly fully into the apatite structure (fluoridation), and a near stoichiometric FA-collagen composite was obtained with complete fluoridation. The freeze-dried composites had a typical biomimetic network, consisting of collagen fibers and precipitates of nano-sized apatite crystals. The human osteoblast-like cells on the FA-collagen composites exhibited significantly higher proliferation and differentiation (according to alkaline phosphatase activity) than those on the hydroxyapatite-collagen composite. These enhanced osteoblastic cell responses were attributed to the fluorine release and the reduced dissolution rate.

Topics: Alkaline Phosphatase; Ammonium Compounds; Apatites; Biomimetics; Bone Substitutes; Calcium; Calcium Phosphates; Cell Differentiation; Cell Proliferation; Collagen; Durapatite; Extracellular Matrix; Fluorides; Fluorine; Humans; Ions; Materials Testing; Microscopy, Electron, Scanning; Osteoblasts; Quaternary Ammonium Compounds; Temperature; Time Factors; X-Ray Diffraction