BIOMINERALIZATION OF HYDROXYAPATITE / TITANIA COMPOSITES PREPARED BY EXPLOSIVE SHOCK WAVES

摘要

The detailed investigations of hydroxyapatite/titania (HA/TiO_2) composites including densification, structural characterization and degradation in human serum were performed. It was concluded that the higher the firing temperature the higher activity of the biocomposites at similar microstructural parameters. Pioneering research of Pruemmer and coworkers proved the formation of various levels of induced stresses and activation of alumina powders. The present work is dealing with the effect of explosive shock waves on the biomineralization of HA/TiO_2 composites after immersion in human serum. Two ceramic composites were prepared and were detonated along with TiO_2 for comparison. The obtained samples were immersed in human serum for 5 sequential periods between 3 and 72 hours at room temperature without agitation. The released calcium, inorganic phosphorus ions and protein in the serum left after withdrawal of solids were measured using relevant biological kits and spectrophotometry at each period. The solids obtained after 72 hours were analyzed by IR spectroscopy. The biomineralization was proved for the higher titania content. The formation of denouvo bone was assessed through scanning electron microscopy (SEM) supplemented by EDAX. The formation of the bio-layer was discussed in view of the activity product and Ca/P ratio besides the Ti-OH~- species formed on immersion.