Data are summarized on the synthesis of hydroxyapatite (HA) by wet-chemical processes, solidstate reactions, and hydrothermal treatment. The conditions for HA preparation via precipitation from solutions of calcium chloride, dibasic ammonium phosphate, and aqueous ammonia are discussed at length. Detailed analysis of the fabrication and properties of calcium-phosphate-based ceramics is presente...

Both glycine and water exhibit a high affinity towards the hydroxyapatite HA surfaces. What happens when they are co-adsorbed at the HA (001) surface? B3LYP periodic calculations reveal that glycine displaces the pre-adsorbed water interacting directly with the HA surface.

It has been suggested that surface modification with a thin hydroxyapatite (HA) coating enhances the osseointegration of titanium implants. However, there is insufficient information about the biological processes involved in the HA-induced response. This study aimed to investigate the inflammatory cell response to titanium implants with either amorphous or crystalline thin HA. Human mononuclea...

Carbonate-substituted hydroxyapatite (CHA) is more osteoconductive and more resorbable than hydroxyapatite (HA), but the underlying mode of its action is unclear. We hypothesised that increased resorption of the ceramic by osteoclasts might subsequently upregulate osteoblasts by a coupling mechanism, and sought to test this in a large animal model. Defects were created in both the lateral femor...

INTRUCTION: Synthetic bone graft such as hydroxyapatite[(Ca10(PO4)6(OH)2] (HA) ceramic have been exhibited high tissue compatibility, osteoconductivity and resistance to infection. However, the insufficient bending strength of HA ceramic, probably too tight to bind of BMPs to HA limit its usage[1]. Various hydroxyapatite /collagen composites were developed as potential biomaterials for bone sub...

Current in vitro systems mimicking bone tissues fail to fully integrate the three-dimensional (3D) microvasculature and bone tissue microenvironments, decreasing their similarity to in vivo conditions. Here, we propose 3D microvascular networks in a hydroxyapatite (HA)-incorporated extracellular matrix (ECM) for designing and manipulating a vascularized bone tissue model in a microfluidic devic...

With its good properties of biocompatibility and bioactivity hydroxyapatite (HA) is highly used as bone substitutes and as coatings on metallic prostheses. In order to improve the bioactive properties of HA, we have elaborated Zn2+ doped hydroxyapatite. Zn2+ ions substitute for Ca2+ cations in the HA structure and four Zn concentrations (Zn/Zn+Ca) were prepared at 0.5, 1, 2 and 5 at.%. To study...

This study concerns the preparation, physical, and in vitro characterization of two different types of hydroxyapatite (HA) microspheres, which are intended to be used as drug-delivery systems and bone-regeneration matrices. Hydroxyapatite nanoparticles (HA-1 and HA-2) were prepared using the chemical precipitation synthesis with H(3)PO(4), Ca(OH)(2), and a surfactant, SDS (sodium dodecyl sulfat...

purpose: to compare the range of motion of hydroxyapatite (ha) and porous polyethylene (medpor) ocular implants in enucleated eyes. methods: this comparative study was performed on records of 34 patients who underwent unilateral enucleation and implantation of hydroxyapatite (13 cases) or medpor (21 cases). the two groups were compared regarding age, gender, cause of enucleation, laterality, an...

The aim of this study was to investigate the sol gel synthesis of HA/FA nanoparticles and the possible formation of TCP phase or unstoichiometric calcium deficient hydroxyapatite (CDHA) from the precursors with a Ca/P ratio of 1.62. In order to prepare the sol, the solutions of Triethyl phosphite, ammonium fluoride and calcium nitrate in ethanol were used respectively as P, F and Ca precursors....