Evaluation of the in vivo biocompatibility of hydroxyapatite granules incorporated with zinc ions

The incorporation of zinc onto biomaterials may improve their biological properties, since it is an essential trace element, involved on important steps of bone remodeling. The aim of this work was to evaluate the in vivo biocompatibility of previously characterized hydroxyapatite granules incorporated with 5% zinc (ZnHA), through a subcutaneous grafting test. Granules produced from powders of ZnHA or stoichiometric HA were subcutaneously grafted onto Balb/c mice, and histomorphometrical analysis was performed at 7, 14, 21, 28 or 60 days after grafting. HA and ZnHA induced a similar foreign body reaction, with formation of granulome and the presence of a fibrous capsule. Granulocytes were virtually absent, and agranulocytes decreased with time. ZnHA treated samples presented faster reduction on multinucleated giant cells and increase on observed angiogenesis, as compared to HA. It could be concluded that ZnHA granules are biocompatible. Further study should better address its potential use for bone therapy

Solution solide d’apatites de plomb, d’argent et de sodium : synthèse, caractérisation structurale et propriétés électriques

A continuous solid solution of Pb$_8$Na$_{\rm 2-x}$Ag$_x$(PO$_4$)$_6$ (0$\leq$ x $\leq$2) crystallizing in the anionic-deficient apatite structure was obtained by solid-state reaction. The samples were characterized by using X-ray diffraction, infrared absorption spectroscopy, Raman scattering spectroscopy, $^{31}$P MAS-NMR and chemical analysis. The electrical conductivity versus x measured in a wide range of temperature increases with silver content. For each composition, conductivity values obey the Arrhenius law. Correlations between electrical and structural properties are established

Kinetics of Pb

Temperature dependence of Pb2+ decays in the hydroxyapatites Ca$_{10-x}$Pbx(PO$_{4})_{6}$(OH)2 has been studied between 25 and 300 K. It has been showed that the process of photoluminescence is mainly controlled by the metastable 3P0 level. The broad emission band at very low temperature is attributed to 3P0 $\to$ 1S0 and at 3P1 $\to$ 1S0 at higher temperature