Papers by Author: Gang Wu

Abstract: PCEC-CaO-SiO₂ hybrid material was synthesized by a two steps method. FTIR results proved the structure of the telechelic PCEC with triethoxysilane-propyl end groups synthesized in the first step. Then the PCEC-CaO-SiO₂ hybrid material was synthesized by Sol-gel method. The chemical link between the functionalized polymer and the organic components prevent the hybrid materials brittle crack. The compressive strength was increased with the inorganic contents increasing in the hybrid materials. The hydrophilic PEG contents of PCEC accelerate the hydroxyapatite deposition on the hybrid materials after it was soaked in the SBF for a period of time.

Abstract: A local drug delivery system constituted by hybrid microsphere/thermosensitive hydrogel was fabricated for Osteoarthritis (OA) therapy in the research. The hydrogel were synthesized by ring-opening copolymerization. Microsphere was fabricated by O/W emulsion and solution evaporation method. The properties of the products were characterized by ¹HNMR, FTIR and phase transition diagram. The microsphere/hydrogel was prepared for in vitro drug release research. The results showed microsphere/hydrogel hybrid system can alleviate initial burst release. After 650 hours, only 60 percent of the drugs were released. Kinetics research implied the drug release is controlled by diffusion/erosion mechanism.

Abstract: Here we report the development of Poly Urethane (PU)/ graphene oxide composite used as the scaffold of anterior cruciate ligament tissue engineering. The influences of the GO on the composite were studied by FTIR, SEM and XRD. The Youngs modulus of the composite is 30.6 MPa compared to that of PU`s 6.8 MPa. The GO induced heterogeneous crystal increasing should be the reason for the composite modulus improving, as well as the interaction between the GO and PU. The good biocompatibility of the composite testified by cell viability experiment indicates the promising candidates of the material as the ACL tissue engineering scaffold.

Abstract: 3D porous scaffolds were produced by a combined salt leaching-phase inverse technique. Results showed that micorpores and macropores distributed in the produced scaffolds with high porosity (more than 75%). The interconnectivity can be influenced by the use of methanol and water as a nonsolvent to induce liquidliquid phase separation. The addition of the nonsolvent and NaCl had influence on compression property of the scaffolds.

Abstract: The purpose of this research was to use mesoporous silicon (mpSi) as internal phase additive to improve the hydrophilic ofloxacin loaded by the hydrophobic PLGA materials through a double emulsion (water-in-oil-in-water) solvent extraction/evaporation method. Laser distribution analysis displayed low impact of MS additive on the final particles size. When compared to particle loading efficiency of none internal phase additives, MS internal phase group showed higher loading efficiency, and it increased with MS amounts inside the microparticles. All the burst releases of MS internal phase groups were severe than none MS group and was directly related the MS amount inside the microsphere. The release rate was increasing with the MS amounts added into the internal phase.

Abstract: The bioactivity of HA has been tested by its osteoconduction ability in vivo. Nano HA has higher specific surface area and was presumed to have high bioactivity. In this paper, nano needle HA was synthesized by the microemulsion method. The properties of such nano materials were analyzed by the XRD and TEM. The impact of the nano HA on the expression of two hBMSCs’ genes, inhibitor differentiation 2 and ostopontin, and the ALP activity was researched in this paper.

Abstract: In the present study, bioactive functional gradient coatings were prepared using net-energy controlled plasma spraying technology. The microstructure and phases of the bioactive functional gradient coating were examined by means of transmission electron microscope, scanning electron microscopy and X-ray diffraction. The results revealed that: (1) as-sprayed coatings contained a large amount of amorphous phases and some nano-sized HA crystals formed during rapid solidification, (2) surface of the coating was very rough with different-sized micropores, and the gradient layer was much denser which firmly bonded to the substrate without gaps and obvious interface between the coating and the substrate

Abstract: In this article, a multilayer tissue engineering scaffold has been fabricated. The uppermost layer is consisted by the collagen and the downmost layer is consisted by the collagen/hydroxyapatide. Between the two layers, there have several continues changed collagen/HA layers at different ratio. These gradient scaffolds have been made by the freeze dried method. The morphology of the multiphase scaffold has been observed by the SEM. The chondrocytes from New Zealand rabbit knee joint were separated, harvested and cultured on the top layer of the scaffold. The histological and the immunohistochemical testing show that the chondrocytes keep its normal type in the 2 culture weeks.

Abstract: For practical applications such as artifical joints and dental implants, there is a strong demand for hydroxyapatite coatings with excellent performances to ensure long-term fixation. In the present study, functionally gradient HA-ZrO2-Bioglass coatings were prepared using net-energy controlled plasma spraying technology. The structural characteristics andmechanical performances of the coatings were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD) and nanoindentation. The results showed that: (1) Pore sizes and compositions of the coatings changed gradually along the vertical substrate, crystal HA with few calcium phosphates was presented in the heat-treated coatings. (2) Surface of the coating was very rough with nano-sized crystalline grains and micropores; (3) Young’s modulus and hardness changed gradually at the range of coating-Ti6Alo4V interface. Compared with HA coatings, the tensile adhesive strength of the functionally graded HA-ZrO2-Bioglass coatings reached 38.6 MPa, much higher than that of single HA coatings.

Abstract: The addition of b-tricalcium phosphate improves the biocompatibility and the bioactivity of scaffolds made from poly(lactic acid)(PLA). In this paper, a developed method was used to prepare poly(lactic acid)/ b-tricalcium phosphate microsphere-based tissue engineered scaffolds. It was found that the porosity and the compressive modulus of the scaffolds increased with increasing stirring time. The PLA scaffolds with a higher strength and porosity could be obtained under the optimum conditions (i.e., 2.0 g of PLA, 0.2 g of b-tricalcium phosphate, 300 rpm, stirring time for 2h ). In addition, the corresponding mechanism has been discussed.