| Bone default repairing material is one of the hotspots of Biomaterial research. During the last ten years, Bone tissue engineering had been becoming the developing direction of this field for many of its merits. Biologic matrix has been developed from bio-poly-materials or bioceramics only to bio-composites. Now, the bio-composites have been confirmed to be one of the developing directions of bone tissue engineering matrix materials.Hydroxyapatite/organic polymer biomedical composite is a hot topic of hard tissue biomaterials research. Hydroxyapatite (HA), the main mineral composition of bone, can form strong bone-bonding with natural bone and has been used extensively for biomedical applications and bone regeneration based on its high biocompatible, bioactive and osteoconductive properties, which has been the research focus of bone repair and substitute materials in resent 20-30 years. However, due to the brittleness, high modulus and fatigue failure in vivo, it is restricted in clinic for un-load bearing bone repair. In order to improve the mechanical property of HA material for hard tissue replacement, study on HA and polymer composite is highlighted. The combination of (HA) bioactivity and (polymer) toughness may result in a new load-bearing bioactive material with good mechanical property, excellent bioactivity and biocompatibility.In this paper, Ca(NO3)2·4H2O, (NH4)2HPO4 and NH4HCO3 were used as starting materials. Calcium-deficient carbonated HA (d-CHA) nanoparticles were synthesized using a precipitation method assisted with microwave irradiation. The influence of different technical parameters such as pH value of the solution, time and power of microwave irradiation on the Ca/P molar rations of HA powders were discussed. XRD, IR and SEM were used to analyze the HA powders. The results showed that calcium-deficient carbonated HA nanoparticles with high performance could be quickly synthesized by irradiating the reaction solution for 1 h at a moderate microwave power. The pH value of solution ranged from 8～10.In order to make a kind of bone tissue engineering matrix material with favorable biocompatibility, mechanical properties and biodegradability, a process which consists of a solvent casting stage, a compression molding stage and a leaching stage had been used to fabricate macroporous composites of PLA and d-CHA. The mechanical properties and degradable characteristics of this material could be controlled by adjusting the components ratio and the porosity. The characters of composites, such as composition, microstructure, porosity, water absorption, compressive strength were analyzed with IR, XRD, SEM and some chemistry methods.The results show that: d-CHA powders synthesized using a precipitation method assisted with microwave irradiation were the best materials to fibracate macroporous composites. The porosity of composites could be different from 60% to 70% when poregen dosage addition was from 60% to 70%, and this porosity was suited cell fostering. The compressive strength of composites was 3MPa, and this compressive strength was suited the demands of bone tissue engineering. When the ratio of PLA and d-CHA was determined, with the increasing of the porogen dosage, the porosity would be increased, and the mechanical properties would be dropped down. Different dosage of PLA andβ-TCP could affect the composites properties. With the same other conditions, d-CHA/PLA=2:8, the composites possessed better advantages for molding and better mechanical properties. The composite samples were immersed in stimulated body fluid(SBF) at 37℃, the samples were characterized by XRD, IR and SEM. The results showed that bone-like apatite was formed on the surface of composites. From the results of degradation experiments, it could be seen that with more PLA given, or amount d-CHA powder reduced, the speed of degrading increased. And the results showed that when d-CHA/PLA was 2:8, the composites possessed mezzo degrading speed and best biodegradability.
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