Calcium phosphate ceramics for biomedical applications

Calcium phosphate compounds have been studied for biomedical applications due to chemical and structural similarity to the mineral phase of bone and tooth. The composition, physico-chemical properties, crystal size and morphology of synthetic apatite are extremely sensitive to preparative conditions and sometimes it resulted into non-stoichiometric calcium deficient hydroxyapatite (HAp) powders. The present paper describes the synthesis of calcium phosphate ceramics powders via a sol-gel method, The powders were sintered at 600 and 800 degrees C. X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDXS) were used for characterization and evaluation of the phase composition, morphology and particle size of samples, The functional group of the coatings were analyzed using Fourier transform infrared (FTIR). The XRD analysis revealed a well crystallized HA structure at both temperatures. At 800 degrees C a small amount of CaO (about 0.4%) was detected. The mean crystallite size, determined from the breadth of the diffraction lines, increases from 30 nm at 600 degrees C to about 110 nm at 800 degrees C. FTIR spectra showed the presence of various PO43- and OH- groups present in the powders. Osteoblast cells were used to determine cell proliferation, viability and citotoxicity after interaction with the prepared bioceramics, by MTT (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, a tetrazole) assay. We note that the viability of HAp-600 starts to decrease after 12h, while the viability of HAp-800 decreases after 6h.