Studies on bioactive glass and glass-ceramic are important research high-lights in the field of biomedical materials. Due to their bioactivity, these materials can form a tight chemical bond with the living bone, when implanted. As a preeminent kind of these materials, A-W(Apatite/Wollastonite) bioactive glass ceramic has not only the excellent bioactivity and biocompatibility, but also the eminent mechanical properties, so it has been largely applied and developed in clinical practice. The development, preparation, properties, applications and the mechanism of its bond with bone are introduced in this paper. We will also put forward the prospect of the research and development of A-W bioactive glass ceramic.
Apatites ; chemistry ; Bone Substitutes ; chemistry ; Calcium Compounds ; chemistry ; Ceramics ; chemistry ; Mechanics ; Research ; Silicates ; chemistry ; Surface Properties

The surface modification using cold plasma technique was introduced to hydroxyapatite(HA). The methods adopted in the study included the formation of bone-like apatite in simulated body fluid and the use of SEM, XPS and XRD. The results showed that the formation of bone-like apatite on HA modified by cold plasma was easier than that without modification. The active mechanism involves the impact of the particles with high energy and high activity against HA, which roughens and etches the surface of HA, heads to the distortion of HA crystal, and thus increases the dissolvability of HA and the local concentration of the Ca and P ions. This approach is helpful to the formation of bone-like appetite. The data demonstrate that the surface modification using cold plasma technique can increase the activity of HA.
Apatites ; chemistry ; Biocompatible Materials ; chemistry ; Cold Temperature ; Durapatite ; chemistry ; Humans ; Plasma ; chemistry ; Surface Properties

A composite material consisting of carbonate apatite (CAp) and type I atelocollagen (AtCol) (88/12 in wt/wt%) was designed for use as an artificial bone substitute. CAp was synthesized at 58 degrees C by a solution-precipitation method and then heated at either 980 degrees C or 1,200 degrees C. In this study, type I AtCol was purified from bovine tail skins. A CAp-AtCol mixture was prepared by centirfugation and condensed into composite rods or disks. The scanning electron-microscopic (SEM) characterization indicated that the CAp synthesized at 58 degrees C displayed a crystallinity similar to that of natural bone and had a high porosity (mean pore size: about 3-10 microns in diameter). SEM also revealed that the CAp heated at 980 degrees C was more porous than that sintered at 1,200 degrees C, and the 1,200 degrees C-heated particles were more uniformly encapsulated by the AtCol fibers than the 980 degrees C-heated ones. A Fourier transformed-infrared spectroscopic analysis showed that the bands characteristic of carbonate ions were clearly observed in the 58 degrees C-synthesized CAp. To enhance the intramolecular cross-linking between the collagen molecules, CAp-AtCol composites were irradiated by ultraviolet (UV) ray (wave length 254 nm) for 4 hours or vacuum-dried at 150 degrees C for 2 hours. Compared to the non cross-linked composites, the UV-irradiated or dehydrothermally cross-linked composites showed significantly (p < 0.05) low collagen degradation and swelling ratio. Preliminary mechanical data demonstrated that the compressive strengths of the CAp-AtCol composites were higher than the values reported for bone.
Animal ; Apatites*/chemistry ; Bone Substitutes*/chemistry ; Bone Transplantation ; Cattle ; Collagen*/chemistry

OBJECTIVETo investigate calcium-phosphate coating on commercial pure titanium substrate using a fast biomimetic procedure.

METHODSThe titanium specimens were divided into two groups, group A and group B. The specimens of group A were only treated with the mixture of H2SO4/HCl for 30 min. The specimens of group B were treated with the mixture of H2SO4/HCl for 30 min, immersed into 5 mol/L NaOH solution at 60 degrees C for 24 h, and then heated to 600 degrees C and maintained for 1 h. All specimens were soaked into simulated body fluid-A (SBF) and SBF-B for each day. The surface morphology was observed by field scanning electron microscopy.

RESULTSDense calcium-phosphate coating deposited on all the titanium surfaces of two groups. The calcium-phosphate coating consisted of spheric structure with a diameter of 1 approximately 3 microm, which was proved to be hydroxycarbonate apatite with the analysis of X-ray diffraction.

CONCLUSIONSThin hydroxycarbonate apatite coating can deposited on pure titanium using a fast biomimetic procedure.

Apatites ; chemistry ; Coated Materials, Biocompatible ; chemistry ; Dental Implants ; Surface Properties ; Titanium ; chemistry ; X-Ray Diffraction

The collagen I was made with the dialysis method of enzymolysising the pig skin, and the static deposition in vitro of calcium phosphate was comparative studied by X-ray diffraction (XRD) and infrared spectroscopy (FTIR) under the condition of pH7. 4, Ca/P 1.67 and whether adding the collagen I into the system. Then the chemical composition of the sedimentary product and the diversification of the collagen I 's IR and Raman spectra (RS) before and after the mineralization were analyzed. The results showed that,under the physiological pH condition that there was not any collagen I, though Ca/P reached up to 1.67, the sedimentary product was CaHPO4 x 2H2O yet, however, after adding collagen I into the system, the bone-like apatite was deposited, which proved that collagen I indeed had the effects on the inducing of the bone-like apatite's mineralization in vitro; there was obviously mutual coordination action between collagen I and its mineralization product--bone-like apatite, which caused that amide peak I red-shifted, amide peak II and amide peak III decreased significantly or disappeared on the IR of collagen I, which maybe was the mechanism that how collagen I induced the depositing of the bone-like apatite.
Animals ; Apatites ; metabolism ; Collagen Type I ; pharmacology ; Osteogenesis ; drug effects ; Skin ; chemistry ; Swine

OBJECTIVETo investigate the apatite forming ability of pure titanium implant after micro-arc oxidation treatment in simulated body fluid (SBF) and obtain implants with calcium phosphate (Ca-P) layers.

METHODSThe implants were immersed in (SBF) after micro-arc oxidation treatment for different time lengths, and their apatite forming ability and the morphology and constituents of the Ca-P layers formed on the sample surface were analyzed using X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, and energy dispersive electron probe.

RESULTSAfter immersion in SBF, large quantities of Ca-P layers were induced on the surface of the samples. The Ca-P layers were composed of octacalcium phosphate and carbonated hydroxyapatite, and the crystals showed a plate-like morphology with an oriented growth.

CONCLUSIONThe implants with micro-arc oxidation treatment show good apatite forming ability on the surface with rich calcium and phosphorus elements. The formed layers are composed of bone-like apatite including octacalcium phosphate and carbonated hydroxyapatite.

Apatites ; chemistry ; Biomimetic Materials ; chemistry ; Body Fluids ; chemistry ; Calcium Phosphates ; chemistry ; Coated Materials, Biocompatible ; chemistry ; Durapatite ; chemistry ; Oxidation-Reduction ; Prostheses and Implants ; Random Allocation ; Surface Properties ; Titanium ; chemistry

OBJECTIVETo prepare a novel apatite-wollastonite bioactive glass-ceramic-calcium sulphate hemihydrate(AW-BGC-CSH) composite, to study its biocompatibility, and to provide experimental support for its further clinical application.

METHODSSamples of AW-BGC-CSH composite were prepared with different AW-BGC granules-CSH ratios (50%, 40%, 30%, 20%). Surface morphology, microstructure and mechanical features of the composite were measured. Osteoblasts were cultivated in vitro on the composite. Cell morphology, proliferation, and the alkaline phosphatase (ALP) activity of osteoblasts were examined to determine the biocompatibility of the composite.

RESULTSThe composite showed a three-dimensional pored structure with communicated micropores under scanning electron microscopy (SEM). The plasticity of the composite could be maintained within 3 - 5 min. Its top solidification temperature was 36.4°C and the maximum compressive strength was 9.3 MPa. The osteoblasts adhered to the composite and grew well. At 1, 3, 5, 7 d after cultivated, the microprotein contents of the composite were (251 ± 12), (296 ± 31), (580 ± 13) and (571 ± 15) mg/L, and the ALP activity of the composite were (4.50 ± 0.68), (6.90 ± 0.27), (12.05 ± 0.28) and (11.86 ± 0.63) U/mg. The results of the ALP activity and microprotein contents in the experiment group were significantly higher than those in the control group (P < 0.05).

CONCLUSIONSThe prepared AW-BGC-CSH composite has a three-dimensional pored structure, favourable plasticity, mechanical property and good biocompatibility.

Apatites ; chemistry ; Biocompatible Materials ; chemistry ; Calcium Compounds ; chemistry ; Calcium Sulfate ; chemistry ; Cells, Cultured ; Ceramics ; chemistry ; Materials Testing ; Osteoblasts ; cytology ; Silicates ; chemistry

A new biocompatible apatite-wollastonite magnetic glass ceramic has been synthesized via sol-gel process. Characteristics of the materials were determined with differential thermal analysis (DTA), X-ray diffraction (XRD), scan electron microscopy (SEM), energy dispersive spectrum (EDS), inductively couple plasma atomic emission spectroscopy (ICP-AES), vibrating sample magnetometer (VSM) and so on. Results showed that the main crystalline phases of the material were hydroxyapatite/fluoroapatite [Ca10(PO4)6(OH, F)), beta-wollastonite[beta-CaSiO3] and calcium europium oxide silicate Ca2Eu8[(SiO4)6O2]. The magnetization of the sample contanining 2% Eu2O3 in weight reached 2.18 emu/g for an applied field of 10 000Oe. Hydroxyapatite layer could form on the surface of the sample while soaking for 14 days in simulated body fluid. Good bioactivity was demonstrated. So it is a potential bone repairing material as well as a hyperthemia treatment material for pateints with cancer.
Apatites ; chemistry ; Biocompatible Materials ; chemistry ; Bone Substitutes ; chemistry ; Ceramics ; chemistry ; Europium ; chemistry ; Magnetics ; Microscopy, Electron, Scanning ; Porosity ; Silicic Acid ; chemistry ; X-Ray Diffraction

This study aimed at investigating the influence of the flow rate of simulated body fluid (SBF) (2 ml/100 ml.min) of body fluid in skeletal muscle upon the formation of bone-like apatite on porous calcium phosphate ceramics. The in vitro immersion experiment in SBF flowing at normal physiological rate is referred to as dynamic SBF. The results showed that bone-like apatite could only formed in the pores of porous calcium phosphate when SBF flow at physiological rate (2 ml/100 ml.min) of body fluid in skeletal muscle. At the same time, bone-like apatite could form both in the pores and on the surface of the samples if the flowing physiological solution is 1.5 SBF. When the flowing speed of SBF is higher than normal physiological speed (10 ml/100 ml.min), no bone-like apatite could be detected both on the surface and in the pores of the materials. This result is in concordance with animal experiments. The dynamic SBF simulates the biological environment of bone-like apatite formation in body better than static SBF (SBF does not flow). This method is very useful for the research of the mechanism of bonelike apatite formation, which is the key step of bone growth on biomaterials, and can be used as an effective approach to investigate mechanism of the osteoinduction of calcium phosphate in nonosseous tissues in vivo.
Apatites ; chemistry ; Body Fluids ; chemistry ; Bone Substitutes ; chemical synthesis ; chemistry ; Calcium Phosphates ; chemistry ; Ceramics ; chemistry ; In Vitro Techniques ; Materials Testing ; Surface Properties

A novel glass-ceramic has been derived from sol-gel process. In this study XRD and FTIR analysis confirmed that the main crystalline phases of the material were hydroxyapatite/fluoroapatite [Ca10(PO4)6(OH,F)] and beta-wollastonite[beta-CaSiO3]; SEM examination showed that the microstructure contained many micro pores of 2-3 microm. After pore-forming, the material possessed good macro porous structure: the size of macro pores was 300-400 microm in diameter, and pores interconnected each other. Bioactivity of the material was preliminarily evaluated in the simulate body fluid. SEM observation revealed that a lot of apatite granules had been formed on the surface of the material after soaking within 7 days. Result shows that the novel sol-gel derived apatite-wollastonite-containing glass-ceramic has good bioactivity. Porous materials have suitable microstructure as well as macrostructure, which make it an excellent material to be used as bone-repairing materials and bone tissue engineering carrier materials.
Apatites ; chemical synthesis ; chemistry ; Biocompatible Materials ; chemistry ; Bone Substitutes ; chemistry ; Ceramics ; chemical synthesis ; chemistry ; Humans ; Materials Testing ; Osseointegration ; physiology ; Osteogenesis ; physiology ; Porosity ; Silicic Acid ; chemical synthesis ; chemistry