Abstract: Porous β-tricalcium phosphate (β-TCP)/ Poly L-lactic acid (PLLA) composites were
prepared by thermally induced phase separation method. The results showed that the composite had
an interconnected pore structure with ～200μm macropores. The inorganic particle content in the
composites varied from 50% to 80% and these particles were homogeneously dispersed in PLLA
matrix. The composites obtained in this study could act as a promising scaffold for bone tissue
engineering because of the pore structure and the mechanical properties.
Abstract: Two starting collagens, sponge and floc collagen, were used to prepare
collagen/tricalcium phosphate (TCP) composites. The resulting composites were porous and had
200μm pore size. However, there was a difference in the microstructure of the pore walls for the
composites derived from the two collagens, the pore walls in sponge collagen/TCP composite
were still porous and had 200 nm micropores size, TCP particles were trapped in collagen
matrices. While floc collagen/TCP composite had smooth and dense walls in which TCP particles
were embedded. The difference could be attributed to the starting collagen with different status.
Sponge collagen has a soft structure, which easily becomes disassembled fibrils during alkali
treatment, the disassembled fibrils are integrated again to form a dense morphology for pore walls
after freeze-drying. While floc collagen has already a low disassembly degree, the alkali treatment
could not be able to separate the fibrils, this remains as micropores in pore walls after
freeze-drying. Both porous composites are significant in bone tissue engineering or regeneration.
MTT test results showed the two composites had good cytocompatibility, and sponge
collagen/TCP composite was somewhat better than floc collagen/TCP composite, which could
result from that micropores derived roughness in pore walls of sponge collagen/TCP composite is
suitable for cell growth.
Abstract: Strontium(Sr) containing CaSiO3 powders were synthesized using chemical precipitation.
X-Ray Fluorescence (XRF) analysis confirmed the incorporation of Sr in CaSiO3. X-Ray diffraction
(XRD) analysis revealed that the incorporation of Sr into the lattice structure of β-CaSiO3 powders,
does not change its β-phase composition. The lattice dimension of β-CaSiO3 powders increased
with the increase of Sr contents (0-10% Sr). Sr-CaSiO3 ceramic disk were prepared from the
Sr-CaSiO3 poweders by uniaxial pressing at 150 MPa and sintering at 1100°C for 3h. XRD and
Differential Thermal Anaysis (DTA) analysis indicated that there is a correlation betweem Sr
concentration (0-10% Sr) and the phase transition from β-CaSiO3 to α-CaSiO3 with the increase of
Sr contents. This transition was promoted by the decrease in temperature.
Abstract: A Bioglass® reinforced polyethylene (Bioglass®/polyethylene) composite has been
prepared, which combines the high bioactivity of Bioglass® and the toughness of polyethylene. The
spatial distribution of Bioglass® particles within the composite is important for the performance of
composites in-vivo. Recent developments in X-ray microtomography (XμT) have made it possible
to visualize internal and microstructural details with different X-ray absorbencies, nondestructively,
and to acquire 3D information at high spatial resolution. In this study, the volume
fraction and 3D spatial distribution of Bioglass® particles has been acquired quantitatively by XμT.
The information obtained provides a foundation for understanding the mechanical and bioactive
properties of the Bioglass®/polyethylene composites.
Abstract: Various reinforcements have been used to reinforce hydroxyapatite composites.
Bioactivity of hydroxyapatite and excellent mechanical properties of titanium make titanium fiber
reinforced hydroxyapatite composite a promising biomaterial. In this work, a titanium fiber was
chosen as the reinforcement, and hydroxyapatite powders prepared by wet precipitation method
were used as matrix material. The interface between titanium fiber and hydroxyapatite was
investigated in terms of microstructure and chemical composition using a combination of scanning
electron microscopy (SEM), X-ray diffraction (XRD) and energy disperse spectroscopy (EDS).
Experimental results showed that titanium/hydroxyapatite composite with controllable interface
could be made by choosing proper preparation method.
Abstract: α-tricalcium phosphate (α-TCP) was prepared by a wet precipitation reaction between
calcium hydroxide and orthophosphoric acid solutions. The as-synthesised powder was then
characterised using a Scanning Electron Microscope (SEM) equipped with Energy Dispersive
Spectroscope (EDS), X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscope (FTIR).
Analyses revealed that a phase-pure powder with a Ca/P ratio of 1.5 was produced. In addition,
nanosized α-TCP particles of diameter ~ 70 nm were agglomerated to form larger particles of 10μm
in diameter. It was found that by the combination of attritor milling and solution evaporation, the
agglomerates of α-TCP nanoparticles could be broken down, and distributed evenly within the
poly(D,L-lactic-co-glycolic acid) (PLGA) matrix. Thus, a α-TCP/PLGA nanocomposite was
successfully produced by a modified solution evaporation method at room temperature followed by
hot pressing at 150 °C. The achievable ceramic loading was approximately 38 wt.%, which was
confirmed by thermal gravimetric analysis (TGA).
Abstract: GTR treatment alone has not led to predictable new periodontal tissue reconstruction.
Recently, various types of tissue substitutes and alloplastic graft have been used in conjunction with
the GTR technique. The aim of this study was to evaluate whether nano-hydroxyapatite/Polylactic
acid (nHA/PLA) and bone-derived materials would be useful in the treatment of class II furcation, in
order to provide an ideal bone replacement material for periodontal treatment. Mucoperiosteal flap
was raised on the buccal aspects of the experimental teeth and class Ⅱ furcation defects were created
surgically on premolars of each quadrant in 3 dogs. The defects were randomly repaired with
nHA/PLA and collagenic membrane, partially deproteinized bone (PDPB) and collagenic membrane.
Blank control group was stayed. Speciments obtained in 6 weeks were evaluated with general
observation, histological microscopic analysis. The specimens of the implanted groups exhibited
periodontal regeneration including newly formed cementum, periodontal ligament and new bone.
The new-formed bone area in sites receiving nHA/PLA and PDPB combined with collagen
membrane was greater than that in blank group.The new bone area in PDPB was smaller than that in
nHA/PLA. nHA/PLA would be better alternative for periodontal regeneration.
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 carbonated. Finally, in vitro cell culture experiments have demonstrated that murine osteoblast
cells attach and grow well on the as-sputtered coatings. These results encourage further studies of
hydroxyapatite thin coatings prepared by the opposing RF magnetron sputtering approach as a
promising candidate for next-generation bioimplant materials.
Abstract: A network-like porous layer on titanium was prepared by acid-etching with a mixture of
CaCl2 and HCl. The pores ranged from 1 to 10!m. The small pores distributed in big pores. In the
simulated biological environment, porous octacalcium phosphate (OCP) coatings spontaneously
formed on the porous- surfaced titanium. Pre-calcification after acid-etching accelerated OCP
precipitation. The OCP coatings had big pores of about 25!m and small pores of 1~3!m, the latter
distributed in the former at different depth.