Síntese e estudo da hidroxiapatita e vanadatoapatita contendo gálio, visando o uso biomédico

Abstract

The elements vanadium and gallium have direct involvement in bone metabolism. Orthovanadate groups in the composition of hydroxyapatite participate in the processes of action and regulation of enzymes related to growth factors. This activity may be due to competition between phosphorus and vanadium in biologically active compounds. On the other hand, the gallium ions are effective against bone resorption, osteoporosis and hypercalcemia. However, none of biomaterials containing vanadium and gallium is presently available. For this reason, this study study was dedicated to the synthesis and investigation of hydroxyapatite and vanadatoapatite containing gallium for use in orthopedic surgery. The main methods used were synthetic procedures, as well as scanning electron microscopy, energy dispersive analysis, X-ray diffraction and elements mapping. A new standard solid phase method has been proposed for the preparation of hydroxyapatite and vanadatoapatite. Its reproducibility is good and it allows obtaining the above compounds with reasonable yields. The methodology includes the introduction of gallium in the form of its nitrate during synthesis of the apatite. Another technique developed for doping process: consists in adding of small amounts of hydroxyapatite in the form of a second phase containing both gallium and vanadium. Finally, we conducted the introduction of gallium in apatites using the process of absorption. In the case of hydroxyapatite it is preferable to use gallium nitrate and ammonium gallate in the case of vanadatoapatite. The results can be used for preparing the compositions with properties permitting the temporarily replacement of a natural bone.