Abstract: The adsorption properties of metal ions containing hydroxyapatite (Ca10(PO4)6(OH)2,
HAp) were elucidated for the development of protein drug carrier. As-prepared metal ion containing
HAp nanocrystal showed plate-like morphology with 10-20nm in length and 5-10nm in width. The
metal ion containing HAp microparticles had higher specific surface area than the HAp microparticle.
The adsorption amount per unit area of HAp showed higher than those of metal ion containing HAp.
The adsorption behavior followed the Langmuir curves for each protein, indicating the monolayer
adsorption. The loaded amount of proteins could be one of the most important properties for the
application of drug delivery carrier.
Abstract: Boron-containing hydroxyapatite (BHAp) particles were synthesized by the wet chemical
processing method and subsequent thermal treatment at the temperature ranging from 700-1200°C,
and examined the effect of boron introduction on the microstructure of BHAp. The local structure
around boron and phosphorus in the BHAp was analyzed by solid-state magic-angle spinning (MAS)
nuclear magnetic resonance (NMR) spectroscopy. The heat-treatment above 700°C induced the
thermal decomposition of HAp to β-TCP and then the chemical reaction between HAp and B(OH)3
was induced above 900°C, resulting in the formation of boron-substituted HAp particles
accompanied by the formation of β-TCP and its transformation to α-TCP above 1200°C.
Abstract: Nanosized hydroxyapatite (nano-HA) in narrow size distribution was prepared in the
microemulsion system. The experimental factors of pH values and temperature were specially
investigated in order to receive nano-HA particles with the required morphologies. Several kinds of
nano-HA with different shapes, sizes and crystallization were obtained by regulating the above
factors in the experiment. After the as-received nano-HA particles were heat-treated at an elevated
temperature, they became a kind of globular particles with an average size of 60nm and showed
excellent disperse ability in absolute alcohol.
Abstract: On this paper, methods to obtain Mg-free reagents for synthesizing pure phase Sistabilized
α-TCP were established. The Mg contents of synthesized reagents were considerably
lower than those in commercially available reactants. Pure Si-doped (2.5 at.-% of P by Si
substitution) α-TCP was obtained by solid state reaction from synthetic reagents at temperature as
low as 1200°C. When commercial reagents were employed for the solid state synthesis, a mixture
of α- and β-TCP was obtained even when the solid state reaction was conducted at 1300 °C.
Abstract: Nanocrystalline hydroxyapatite was prepared by a precipitation method with add of ultrasonic
irradiation. In this work the effect of H3PO4 addition rate during synthesis and the influence of
the magnesium incorporation into apatite were studded. The results revealed that the morphology
and cristalinity of synthesized nanopowders are significantly affected by ultrasonic irradiation. Monophase
hydroxyapatite was obtained when magnesium was added into HA lattice during the synthesis
with ultrasonic irradiation.
Abstract: A systematic study of the stability of potassium/carbonate co-substituted hydroxyapatite
has been carried out, with samples synthesized by aqueous precipitation according to the chargebalanced
Samples up to x=1.0 were prepared and their stability determined by heating at a range of
temperatures in both air and CO2 environments. Results showed that whilst samples up to x=1.0
can be prepared phase-pure, the stability of these materials is strongly dependent on sintering
temperature with the full range of compositions only being stable at 600°C in CO2. The c unit cell
parameter increases linearly with x, and, for a fixed composition, decreases linearly with
temperature indicating loss of carbonate from the A-site. FTIR showed that samples contained
carbonate at both A- and B-sites, and that carbonate content increased with x.
Abstract: The low temperature macro and micro porous hydroxyapatite scaffold was synthesized.
The synthetic nanostructured HA powder was prepared by the reaction of Ca(OH)2 and H3PO4. The
ultrasound apparatus was used for the separation of the particles during the precipitation process.
Hydrogen peroxide (H2O2) was used as a foaming agent. The samples were dried for 3 hours at
120°C. HA (hydroxyapatite) granules exhibited interconnected macro and micro porosity with the
micro pore size in the order of 0.01 'm. The specific surface area of the precipitate reached the
average value 64.8 ± 11.9 [m2.g-1]. The compressive strength of the low temperature porous HA
scaffold granule was very similar to deproteinized bovine bone and other calcium phosphate
ceramic materials used in bone regeneration and prepared by high temperature processes. The
porosity of the scaffolds 50-75% was determined by mercury porosimetry. In-vitro cytotoxicity test
proved the granules to be non toxic.
Abstract: Crystalline hydroxyapatite thin coatings have been prepared using a novel opposing RF
magnetron sputtering approach at room temperature. X-ray diffraction (XRD) analysis shows that
all the principal peaks are attributable to HA, and the as-deposited HA coatings are made up of
crystallites in the size range of 50-100nm. Fourier transform infrared spectroscopy (FTIR) studies
reveal the existence of phosphate, carbonate and hydroxyl groups, suggesting that HA coatings are
highly crystalline. To study the biocompatibility of these coatings, murine osteoblast cells were
seeded onto various substrates. Cell density counts using fluorescence microscopy show that the
best osteoblast proliferation is achieved on an HA RAMS-coated titanium substrate. These
experiments demonstrate that RAMS is a promising coating technique for biomedical applications.
Abstract: Bone is a complicated heterogeneous, viscoelastic, anisotropic material. Its properties
depend on the nature of mechanical forces in addition to the location as well as the age, sex and race
of the subject. Human humerus bones retrieved from cadavers were selected and separated in to
cortical and cancellous parts. They were heat treated at different temperatures 400°C, 600°C and
800°C respectively to study the crystalline nature and composition of cortical and cancellous region
of the humerus bone separately. Hydroxyapatite (HAP) was present as the major phase in the bone
powders at 600 and 800°C with well resolved peaks along with other mineral phases of calcium
phosphate. No amorphous phases were present indicating that the crystal structure of calcium
phosphate compounds is present in crystalline form. FTIR studies further confirm the presence of
phosphate vibrational modes of the entire bone mineral along with the presence of carbonates and
Abstract: In vitro reactions of bundles of fibers with diameters 20-500 μm and crushed glasses of
fractions 500-800 μm were compared with the reactions of plates of the same bioactive glasses. The
samples were immersed in simulated body fluid (SBF) for 2-7 days. After immersion the changes
on the surfaces of the samples were observed by SEM/EDXA. Layer formation on the glass surface
was found to vary with glass composition, sample shape and local condition of single particle/fiber.
However, only some fibers or particles formed similar in vitro reaction layers as the plates. The
product form did not change the in vitro bioactivity of particles or fibers exposed to the bulk
immersion solution. When the glasses were used as fiber bundles or particle beds, the packing
degree and the flow of body fluids within the system interfered with the reactivity. Also a clear
correlation between in vivo layer formation in bone and in vitro of the glass plates could be found.