Synthesis and characterization of silicon substituted hydroxyapatite

A silicon-substituted hydroxyapatite has been prepared using tetraethylorthosilicate as a silicon source to obtain a biomaterial having an improved biocompatibility. From the XRD analysis, it was confirmed that the single-phase hydroxyapatite containing silicon has formed without revealing the presence of extra phases related to silicon oxide or other calcium phosphate species. Silicon content was up to 3.32% by weight. (29)Si MAS NMR investigation elucidated the presence of tetrahedral silicate in the framework of hydroxyapatite structure. Substitution of silicon into the hydroxyapatite framework (Ca(10)(PO(4))(6-x)(SiO(4))(x)(OH)(2-x)) reduced the amount of hydroxyl group to compensate for the extra negative charge of the silicate group, which is confirmed by FT-IR.