title: TEM study of calcium phosphate precipitation on bioactive titanium surfaces.
abstract: Formation of calcium phosphate on alkali- and heat-treated titanium surfaces was investigated using transmission electron microscopy (TEM). The samples were prepared by immersing the alkali- and heat-treated titanium in a revised simulated body fluid (R-SBF) with the same HCO(3)(-) concentration level as in human blood plasma. The deposition and precipitation on treated titanium surfaces were extracted for TEM examination without thinning process. Electron diffraction of the precipitates revealed that octacalcium phosphate (OCP), instead of hydroxyapatite (HA), directly nucleates from amorphous calcium phosphate. The OCP crystals continuously grew on the titanium surfaces rather than transforming into apatite. Calcium titanate was also identified by electron diffraction. Its role in the formation bioactive calcium phosphate, however, is not clear from this experiment.
authors.affiliation: Department of Mechanical Engineering, Hong Kong University of Science and Technology, Kowloon, Hong Kong.
authors.forename: Xiong
authors.initials: X
authors.lastname: Lu
authors.forename: Yang
authors.initials: Y
authors.lastname: Leng
mesh_terms: D040761:Biomimetic Materials / Q000737:chemistry; D001826:Body Fluids / Q000737:chemistry*; D002130:Calcium Phosphates / Q000138:chemical synthesis / Q000737:chemistry*; D011232:Chemical Precipitation; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D008422:Materials Testing; D008854:Microscopy, Electron; D008968:Molecular Conformation; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry*
chemical_list: D002130:Calcium Phosphates; D020099:Coated Materials, Biocompatible; C519480:amorphous calcium phosphate; C020243:calcium phosphate; D014025:Titanium