title: Nucleation and growth of hydroxyapatite on an amino organosilane overlayer.
abstract: An amino organosilane overlayer (NH(2)-overlayer) was successfully processed on Si/SiO(2) substrates. Remarkable nucleation and growth of hydroxyapatite were found to take place on an NH(2)-overlayer after Si/SiO(2) substrates covered with the NH(2)-overlayer were soaked in supersaturated solutions with respect to Ca(2+) and PO(4)(3-) ions [1.0SBF (simulated body fluid), which contains similar compositions to that in a living body and 1.5SBF in which only Ca(2+) and PO(4)(3-) concentrations are 1.5 times than that in 1.0SBF]. The experimental results demonstrated that HAp nucleation on an NH(2)-overlayer is related to the electrostatic attractive force between positive NH(2)-overlayer surface and negative incipient HAp microparticles homogeneously nucleated in 1.5SBF solution at 50 degrees C. On the contrary, fewer HAp particles were observed on negatively charged "OH" terminated self-assembled monolayer (SAM) because of the repulsive interaction. The Ca/P molar ratios of HAp particles increased from 0.92 at the beginning of nucleation in 1.5SBF to 1.63 in 14 days after growth in 1.0SBF at 37 degrees C. After 14 days of soaking in 1.0SBF, a dense HAp film with the thickness up to 8.6 microm was formed on the NH(2)-overlayer.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Nagoya, Japan.
authors.forename: P X
authors.initials: PX
authors.lastname: Zhu
authors.forename: M
authors.initials: M
authors.lastname: Ishikawa
authors.forename: W S
authors.initials: WS
authors.lastname: Seo
authors.forename: A
authors.initials: A
authors.lastname: Hozumi
authors.forename: Y
authors.initials: Y
authors.lastname: Yokogawa
authors.forename: K
authors.initials: K
authors.lastname: Koumoto
mesh_terms: D001672:Biocompatible Materials / Q000138:chemical synthesis* / Q000737:chemistry; D001826:Body Fluids / Q000737:chemistry; D017886:Durapatite / Q000138:chemical synthesis* / Q000737:chemistry; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D017646:Organosilicon Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D010316:Particle Size; D013499:Surface Properties
chemical_list: D001672:Biocompatible Materials; D017646:Organosilicon Compounds; D017886:Durapatite