title: Synthesis and characterization of silver/silicon-cosubstituted nanohydroxyapatite.
abstract: Favorable cell-material interaction and the absence of undesirable reaction from the host body defence system play a critical role in determining the success and long-term survival of the implants. Substitution of various elements into hydroxyapatite (HA) has been done to alter its chemical composition, thereby mimicking that of the bone mineral. In this study, a cosubstituted nanosized apatite (Ag/Si-HA) containing Ag (0.3 wt %) and Si (0.8 wt %) was synthesized by an aqueous precipitation technique. The synthesized Ag/Si-HA displayed a rod-like morphology of dimensions ~50 nm in length and ~15 nm in width, as observed from the transmission electron microscope image. With an increase in temperature, the aspect ratio of nanosized Ag/Si-HA decreased, whilst the size increased. Autoclaving was used to achieve sufficient crystallinity while maintaining the rod-like morphology and size that were comparable to that of the bone apatite. A pure Ag/Si-HA was produced without any undesirable secondary phases, as evidenced from the X-ray diffraction and thermal gravimetric results. The Ag/Si cosubstitution affected the lattice cell parameters, in particularly the a- and c- axes which further led to an expansion of the unit cell volume. In addition, the relative intensity of the hydroxyl vibrational bands was reduced. These results demonstrated that a stable phase-pure Ag/Si-HA was produced using an aqueous precipitation reaction.
authors.affiliation: Department of Mechanical Engineering, National University of Singapore, Singapore, Singapore.
authors.forename: Poon Nian
authors.initials: PN
authors.lastname: Lim
authors.forename: Bee Yen
authors.initials: BY
authors.lastname: Tay
authors.forename: Cynthia Mingli
authors.initials: CM
authors.lastname: Chan
authors.forename: Eng San
authors.initials: ES
authors.lastname: Thian
mesh_terms: D001842:Bone and Bones / Q000737:chemistry; D017886:Durapatite / Q000138:chemical synthesis* / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*
chemical_list: D012834:Silver; D017886:Durapatite; D012825:Silicon