title: In vitro apatite formation on organic-inorganic hybrids in the CaO-SiO(2)-PO (5/2)-poly(tetramethylene oxide) system.
abstract: The osteoconduction potential of artificial materials is usually evaluated in vitro by apatite formation in a simulated body fluid (SBF) proposed by Kokubo and his colleagues. This paper reports the compositional dependence of apatite formation on organic-inorganic hybrids in the CaO-SiO(2)-PO(5/2)-poly(tetramethylene oxide) system, initiated from tetraethoxysilane (TEOS), triethyl phosphate (OP(OEt)(3)), calcium chloride (CaCl(2)) and poly(tetramethylene oxide)(PTMO) modified with alkoxysilane. Formation of an apatite layer was observed on the surface of the organic-inorganic hybrids with molar ratios of TEOS/OP(OEt)(3) ranging from 100/0 to 20/80. The rate of apatite formation remarkably decreased when the hybrids were synthesized with TEOS/OP(OEt)(3) ratios of 40/60 or less. Hybrids without TEOS showed no apatite formation in SBF for up to 14 days. Addition of small amounts of OP(OEt)(3) to TEOS in the hybrids led to the high dissolution of calcium and silicate, while addition of large amounts of OP(OEt)(3) decreased the dissolution of calcium and silicate ions and resulted in reduced apatite formation regardless of the dissolution of phosphate ions from the hybrids.
authors.affiliation: Graduate School of Engineering, Nagoya University, B2-3 (611), Furo-cho, Chikusa-ku, Nagoya, 464-8603, Japan. koh.miyoung@h.mbox.nagoya-u.ac.jp
authors.forename: Mi-Young
authors.initials: MY
authors.lastname: Koh
authors.forename: Masanobu
authors.initials: M
authors.lastname: Kamitakahara
authors.forename: Ill Yong
authors.initials: IY
authors.lastname: Kim
authors.forename: Koichi
authors.initials: K
authors.lastname: Kikuta
authors.forename: Chikara
authors.initials: C
authors.lastname: Ohtsuki
mesh_terms: D001031:Apatites / Q000138:chemical synthesis*; D001826:Body Fluids / Q000737:chemistry*; D018786:Bone Substitutes / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry*; D003460:Crystallization / Q000379:methods; D006018:Glycols / Q000737:chemistry*; D007287:Inorganic Chemicals / Q000737:chemistry; D008422:Materials Testing; D009930:Organic Chemicals / Q000737:chemistry; D010087:Oxides / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*
chemical_list: D001031:Apatites; D018786:Bone Substitutes; D017610:Calcium Compounds; D006018:Glycols; D007287:Inorganic Chemicals; D009930:Organic Chemicals; D010087:Oxides; C047554:polytetramethylene glycol; D012822:Silicon Dioxide; C016538:lime