BG/PHBV复合多孔组织工程支架材料的动物植入实验观察

本文研究了溶胶-凝胶生物玻璃／聚羟基烷酸脂(BG／PHBV)复合多孔支架材料与成骨细胞的生物相容性,并对植入动物体内的BG／PHBV和羟基磷灰石／聚羟基烷酸脂(HA／PHBV)两种材料的成骨情况进行了SEM跟踪测试。结果表明：在动物实验中,与HA／PHBV复合多孔支架材料相对照,BG／PHBV植入后,新生骨形成时间早,骨修复完成时间早,降解速度快。     

生物玻璃/聚乳酸多孔微球的制备及其作为细胞载体的研究

具有大孔结构的多孔微球既可以在体外扩增细胞,还可以作为细胞的传输工具,通过注射的方式把细胞输送到需要修复的组织部位。生物玻璃虽然生物活性良好,但难以直接制备成大孔结构的微载体。因此,本研究将生物玻璃(BG)与聚乳酸(PLA)高分子复合,通过复乳法制备了一种含生物玻璃的多孔微球细胞微载体。并通过扫描电镜(SEM)、热重分析(TGA)、电感耦合等离子体发射光谱仪(ICP-OES)等方法研究分析了微球的形貌、组成和离子释放。通过细胞实验,证明细胞可以在微球的多孔结构中粘附和增殖,并且生物玻璃可以促进细胞增殖,在组织工程中具有潜在应用。     

Competent F18 bioglass-Biosilicate® bone graft scaffold substitutes

Biosilicate® glass-ceramic (BioS) offers an attractive choice for the manufacturing of scaffolds because of their high bioactivity, non-toxicity, bactericidal activity and biodegradability. Despite these positive properties, Biosilicate® scaffolds that have been developed so far show low fracture strength, limiting their clinical application. For this reason, our aim was to increase their strength through vacuum infiltration of F18 bioactive glass. First, we calculated the maximum attainable theoretical compressive strength of a scaffold using the Ryshkewitch and Ashby-Gibson models. We show that for a total porosity of 80 %, σ₀ = 250 MPa, and n = 5 the compressive strength estimated by both models is approximately 4.5 MPa. Afterward, the Biosilicate scaffolds were prepared using the foam replica technique and recoated several times with a F18 glass slurry to eliminate surface defects. Scanning Electron Microscopy examination showed that the F18 indeed helped to remove surface defects and partially infiltrated the hollow struts, significantly increasing their mechanical integrity. The F18-BioS scaffolds exhibited a total porosity of 82 %, an average cell size of 525 μm, and compressive strength of 3.3 ± 0.3 MPa, which is close to the predicted value and significantly higher than those of sole BioS scaffolds of a similar structure (< 0.1 MPa). These values are within the range of commercial scaffolds based on Hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), having a considerable advantage of being more osteoinductive, angiogenic, and highly bactericidal. The F18-BioS scaffolds developed in this work thus have high potential for odontology or craniofacial surgeries that do not involve high load–bearing conditions.     

组织工程用β-磷酸三钙生物活性支架材料的显微结构及性能

以萘粉作造孔剂,聚乙烯醇作粘结剂,以β-磷酸三钙、生物活性玻璃等材料研制生物活性组织工程支架用复合材料。用XRD,SEM等研究手段,对多孔陶瓷的性能、微观结构、及其制造工艺对材料性能影响规律进行了研究。结果表明：所制备支架材料孔隙率达75％,抗弯强度可达4．4MPa,孔径为200～400μm。实验还表明：随烧结温度升高,孔隙率随之降低,抗弯强度提高。     

Processing of ZrO2 scaffolds coated by glass–ceramic derived from 45S5 bioglass

Three dimensional, highly porous, ZrO₂ scaffolds coated by glass–ceramic derived from 45S5 bioglass were fabricated. The surface reactivity of 45S5 in aqueous solution was investigated as a function of the immersion time. The influence of the solid loading on the rheological behavior of 45S5 aqueous slips with ammonium polyacrylate (NH₄PA) was studied; besides the effect of poly(vinyl)alcohol (PVA) on the relative viscosity was determined. The structure and microstructure of uncoated and coated ZrO₂ scaffolds were characterized. The high ionic exchange capability of 45S5 was demonstrated by the pH rise, the significant weight loss and the amorphous calcium phosphate nucleation, upon its immersion in aqueous solution. The addition of PVA did not affect the dispersion properties of the 45S5 powder, which were basically controlled by its negative surface charge. 30 wt% 45S5 slips with 4 wt% PVA exhibited a yield stress and an adequate viscosity in the low shear rate range, to produce a bioglass coating into the ZrO₂ scaffold. The glass-ceramic coating was distributed along the strut surfaces, forming a thin film without altering the porosity and the strut thickness of the original ZrO₂ scaffold structure.