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....

BACKGROUND AND PURPOSE Hydroxyapatite has been used for a long time as an adjunct to enhance cementless fixation. The benefit of this is still debated, but new methods of hydroxyapatite deposition have emerged, offering possible gains. In order to investigate this further, we compared the migration pattern and periprosthetic bone remodeling in a cementless femoral stem with either electrochemic...

This work focuses on studying the effect of sintering temperature ,pressing pressure and sintering time (soaking time) on phases generated, porosity and fracture strength of sintered HA powder compact at a range of (800-1200) ̊C , (38.378-153.513)Mpa and (1-5)hr respectively, and evaluation of sintered HA powder compact in synthetic body fluids(SBF), to indicate the biological bioactivity . Both...

Macroporous single phase hydroxyapatite (HA) and biphasic HA/β-tricalcium phosphate with 33% post-sinter hydroxyapatite (HA/β-TCP) were combined with 25 or 125 μg recombinant human transforming growth factor-β3 (hTGF-β(3)) to engineer a super activated bioreactor implanted in orthotopic calvarial and heterotopic rectus abdominis muscle sites and harvested on day 30 and 90. Coral-derived calcium...

The ideal bone substitute biomaterial should have mechanical properties similar to that of human bone tissue. Hydroxyapatite (HA) alone suffers from low fracture toughness, and most polymers alone lack sufficient stiffness and strength, limiting applications in load-bearing implants. Synthetic HA whisker reinforced polymer biocomposites provide a means to overcome these deficiencies (Roeder, et...

The bioactivity of hydroxyapatite (HA) coatings can be modified by the addition of different ions, such as silicon (Si), lithium (Li), magnesium (Mg), zinc (Zn) or strontium (Sr) into the HA lattice. Of the ions listed here, strontium substituted hydroxyapatite (SrHA) coatings have received a lot of interest recently as Sr has been shown to promote osteoblast proliferation and differentiation, ...

Human osteoblastic bone marrow cells were cultured for periods of up to 28 days in control conditions and on the surface of a glass reinforced hydroxyapatite composite (HA/G1) and commercial hydroxyapatite (HA) plasma-sprayed coatings, in the "as-received" condition and after immersion treatment in culture medium for 21 days. Cultures were characterized for total protein content and alkaline ph...

The normal intersurface forces between nanosized probe tips functionalized with COO(-)-terminated alkanethiol self-assembling monolayers and dense, polycrystalline silicon-substituted synthetic hydroxyapatite (SiHA) and phase pure hydroxyapatite (HA) were measured via a nanomechanical technique called chemically specific high-resolution force spectroscopy. A significantly larger van der Waals i...

This paper explores the nano-scratch technique for measuring the adhesion strength of a single osteoblast cell on a hydroxyapatite (HA) surface reinforced with carbon nanotubes (CNTs). This technique efficiently separates out the contribution of the environment (culture medium and substrate) from the measured adhesion force of the cell, which is a major limitation of the existing techniques. Na...