Abstract: In this paper, carbonated calcium-deficient hydroxyapatite (d-HA) nanoparticles were
synthesized by a chemical precipitation method assisted with microwave irradiation. The important
factors which effected on the synthesis process, such as pH value, time and the power of microwave
irradiation on the Ca/P molar ratios of d-HA were discussed. The experimental results showed that
carbonated d-HA nanoparticles could be quickly synthesized by irradiating the reaction solution for about
1h under moderate microwave power and pH value ranging from 8 to 9.
Abstract: Two kinds of dense calcium phosphate (Ca-P) bioceramics, hydroxyapatite (HA) and β-
tricalcium phoshpate/hydroxyapatite (β-TCP/HA), sintered by microwave plasma were investigated. The
dense HA and β-TCP/HA bioceramics exhibited higher density, smaller grain size and higher Vickers
hardness. The sintering behaviors of HA powder were also significantly different from those of calciumdeficient
hydroxyapatite (d-HA) powder by the same microwave plasma sintering route. The sintering
efficiency of the former was higher than that of the latter. The results indicate that dense HA and
β-TCP/HA bioceramics are of better mechanical strength and might have better bioactivity.
Abstract: Porous HA/TCP bioceramics were immersed in pure bovine serum to observe the growth and
formation of apatite. HRTEM, FTIR, and SEM coupled with EDS were used for the characterization of
immersed samples. SEM results showed that some beamed crystals formed on the surface of ceramics
granules, and with postponement of immersion time, crystals extended and became bigger, strap-like
crystals became sheet-like crystals. HRTEM observations indicated that new-formed crystals developed
along axes direction according to parallel layers. IR spectrum showed CO3
2- characteristic peaks existed
besides O-P-O and OH- characteristic peaks. EDS results showed that calcium and phosphor ratio was
1.95 (mol ratio). The results indicated that bovine serums were advantaged to bone-like apatite formation.
Abstract: The crystalline structures of B-type carbonated hydroxyapatite (CHA) powders sintered at 700,
900 and 1100°C, respectively, were studied by Rietveld analysis of powder X-ray diffraction (XRD) data.
A series of structure parameters, including lattice parameters (a and c), bond length and the distortion
index of PO4 tetrahedron (Dind) were calculated by Rietveld method to characterize the fine structure of
CHA. The broadening effect of XRD reflections was separated to calculate the micro-strain and
crystalline size. The results showed that CHA become more stable with the increase of sintering
temperature, but the CO3
2- is almost lost at temperature of 1100°C. The quantitative results about crystal
structure of CHA based on crystalline structure simulated by Rietveld method are obtained.
Abstract: Porous hydroxyapatite (HA) bioceramic matrix with interconnected ducts was obtained using a
porogen burnout technique at 1200°C. The HA/silk fibroin (SF) composite scaffolds were developed with
the SF sponges formed inside the pores and ducts of the bioceramics by first introducing HA/SF slurries
into the pores and ducts followed by a freeze-drying process. Phase components and morphology of
materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM),
respectively. Porosity was measured by Archimedean method. Compressive strength was also measured.
The simulated body fluids (SBF) experiments were conducted to evaluate bioactivity. The results show
that hydroxyapatite is the main phase compositions after sintering at 1200°C. The porosity of composite
scaffolds reaches 70%~80%. The sizes of pores and ducts of HA matrix range from 150μm to 400μm and
the pore sizes of SF sponges formed inside the macroporous structure of bioceramics are approximately
100μm,a structure favorable for bone tissue in-growth. The compressive strength of the composite
scaffolds is greatly improved in comparison with that of HA matrix. In the SBF tests, a layer of randomly
oriented apatite crystals form on the scaffold surface after sample immersion in SBF. The cell culture
experiments show that the osteoblast cells are attached and proliferated on the surface of the composite
scaffold, which suggest good bioactivity and cellular compatibility of the composite material.
Abstract: Rare earth/calcium phosphate composite coatings were fabricated on the surface of Ti-6Al-4V
by micro-arc oxidation (MAO) technique. The wear properties and corrosion resistant of rare earth/
calcium phosphate composite coatings in the simulated body fluid (SBF) have been investigated and the
bioactivity of the composite coatings were evaluated. The results show that the friction coefficient of the
composite coatings in the SBF is only 0.15~0.18 and the anode polarization potential of the coating has
been obviously enhanced about 0.18V compared with that of coatings of calcium phosphate coatings. So
the composite coatings have excellent wear and corrosion resistant properties. XRD analysis indicates
that the composite coatings can induce hydroxyapatite to form on its surface after soaked in SBF for 9d,
which shows that the composite coatings own good bioactivity.
Abstract: This study examined the bioactive and stability of calcium phosphate- polypyrrole(ppy)
composite coatings on titanium alloys by electrochemically deposition in simulated body fluid (SBF).
Change of coatings mass and SBF pH during coatings soaked in SBF indicated that ppy reduces the
decomposition of coatings. The surface morphology of coatings characterized by SEM showed that the
stability of composition coating was superior to that of single coating. XRD indicated that ppy induces
2- enter calcium phosphate coating, which showed that the composite coatings possess better
bioactive. Thus, this electrochemical deposition provides an effective method of ppy incorporation at
physiological temperature, which can offer excellent bioactive and stability of coatings, with a potential
for sustained release of therapeutic agents as required for metallic implant fixation.
Abstract: Porous bioactive thin film on commercially pure titanium substrate was prepared by micro-arc
oxidation (MAO) in electrolytic solution, which contained calcium acetate, β-glycerol phosphate
disodium salt pentahydrate (β-GP) and lanthanum nitrate. The phases and microstructure of the bioactive
films were examined by X-ray diffraction, scanning electron microscopy with energy dispersive X-ray
spectrometer and electron probe microanalysis. The results showed that: (1) porous bioactive films with
about 10μm were formed on titanium substrate by MAO; (2) phases of the thin films were hydroxyapatite,
anatase and rutile; (3) elements of Ca, P, and Ti of films were identified by EDS.
Abstract: Based on a high power CO2 laser beam passing by pyramid polygon mirror, the bioceramic
coatings of gradient composition were fabricated on titanium alloy substrate (Ti-6Al-4V). The relations
among laser processing parameters, microstructure and biocompatibility of the gradient bioceramic
coatings were investigated. The results indicated that the contents of rare earth oxide additions had an
immediate effect on the formation of bioactive phases. The gradient bioceramic coatings showed
favorable biocompatibility in vivo after they were implanted into canine femur for 45, 90, and 180 days,
respectively. The bioceramic coatings of Ca/P=1.4 and 0.6wt.% Y2O3 totally combined with new bones
merely implanted for 45 days. Furthermore, the MTT (Methyl Thiazolyl Tetrazolium) colorimetry results
of cell proliferation demonstrated that the cell growth distinctly increased on the gradient bioceramic
coatings by laser cladding compared with the un-treated titanium alloy substrate.
Abstract: Biphasic tricalcium phosphate (BTCP) powders composed of α-tricalcium phosphate (α-TCP)
and β-tricalcium phosphate (β-TCP) were prepared using amorphous calcium phosphate (ACP) precursor
after heat treatment at 800oC. The in vitro dissolution behavior of the powders was examined after soaked
in 0.1M NaAc-HAc buffer solution for different times. It was revealed that the Ca2+ and PO4
concentration, and pH value of the BTCP-soaked solution are higher than those of the α-TCP- and
β-TCP-soaked solutions. The dissolution behavior of BTCP powders was explained. The specific
dissolution behavior of BTCP powders can widen the biodegradation range of calcium phosphate family.