title: Stability and cellular responses to fluorapatite-collagen composites.
abstract: 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.
authors.affiliation: School of Materials Science and Engineering, Seoul National University, San 56-1 Sillim-Dong, Kwanak-Gu, Seoul 151-744, Republic of Korea.
authors.forename: Byung-Ho
authors.initials: BH
authors.lastname: Yoon
authors.forename: Hae-Won
authors.initials: HW
authors.lastname: Kim
authors.forename: Su-Hee
authors.initials: SH
authors.lastname: Lee
authors.forename: Chang-Jun
authors.initials: CJ
authors.lastname: Bae
authors.forename: Young-Hag
authors.initials: YH
authors.lastname: Koh
authors.forename: Young-Min
authors.initials: YM
authors.lastname: Kong
authors.forename: Hyoun-Ee
authors.initials: HE
authors.lastname: Kim
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D064751:Ammonium Compounds; D001031:Apatites / Q000737:chemistry*; D032701:Biomimetics; D018786:Bone Substitutes / Q000737:chemistry*; D002118:Calcium / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry; D002454:Cell Differentiation; D049109:Cell Proliferation; D003094:Collagen / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D005109:Extracellular Matrix / Q000378:metabolism; D005459:Fluorides / Q000737:chemistry*; D005461:Fluorine / Q000737:chemistry*; D006801:Humans; D007477:Ions; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D010006:Osteoblasts / Q000378:metabolism; D000644:Quaternary Ammonium Compounds; D013696:Temperature; D013997:Time Factors; D014961:X-Ray Diffraction
chemical_list: D064751:Ammonium Compounds; D001031:Apatites; D018786:Bone Substitutes; D002130:Calcium Phosphates; D007477:Ions; D000644:Quaternary Ammonium Compounds; D005461:Fluorine; C024822:ammonium fluoride; D003094:Collagen; D017886:Durapatite; D000469:Alkaline Phosphatase; C025105:fluorapatite; D005459:Fluorides; D002118:Calcium