'Middle East Technical University, Faculty of Architecture'
Abstract
In the case of bone defects and damages synthetic bone grafts have been widely used for filling the damaged parts. Alpha-tricalcium phosphate (α-TCP) is an attractive calcium orthophosphate as replacement of hard tissues. It converts from powder form to hardened apatite, by cement-type reaction in aqueous solutions, which is therefore a promising hard bone tissue analog and clinically used in bone defect filling operations. In this concept adding therapeutic function to the hardened cement products is an additional challenge and research interest. When compared with organic drugs and proteins, metallic ions are promising therapeutic agents because of their high availability and stability. In order to improve the therapeutic properties of α-TCP, various metallic ions can be incorporated. In this study, selenium (Se) ion has been incorporated to α-TCP to give anti-carcinogenic effect. Se-incorporated α-TCP (α-TCP:Se) has been synthesized by the solid-state reaction of custom synthesized Se-incorporated monetite (CaHPO4:Se) and calcium carbonate (CaCO3). The microstructural and morphological properties of as synthesized α-TCP products with different amounts of Se-incorporation remain unaffected by doping. Up to 2 wt. % Se-incorporation, the only phase obtained from the XRD analyses is α-TCP, however, higher than 2 wt. % Se-incorporation to α-TCP leads to formation of the hydroxyapatite (HAp) together with α-TCP. Complete cement-type conversion from α-TCP to calcium-deficient hydroxyapatite (CDHAp) has been performed with pure and different amount of Se-incorporated α-TCP products. The hydration kinetics of cement-type conversion is positively changed with the presence of Se. Higher amount of Se addition slows down the kinetics of cement-type conversion. The morphological properties are remained same for Se-incorporated and pure α-TCP. Less than 2 wt. % Se doping is critical limit for obtaining only α-TCP without formation of any other calcium phosphates and it’s critical for faster hydration kinetics of cement conversion reaction from α-TCP to CDHAp.M.S. - Master of Scienc
