聚乳酸-羟基乙酸共聚物/磷酸钙骨水泥多孔复合支架的制备

利用定向冰晶-冷冻干燥法制备了具有定向孔隙结构的磷酸钙骨水泥支架材料, 将两种具有不同降解速率的聚乳酸-羟基乙酸共聚物(PLGA) 与磷酸钙骨水泥多孔支架进行多次浸润复合, 以改善支架的力学性能。结果表明: PLGA 与支架材料复合可大大提高复合支架材料的抗压强度, 经过PLGA 二次复合后, 复合支架抗压强度可达6. 37 MPa ±0. 54 MPa 。经过PLGA 复合的支架材料保持了复合前的孔隙结构, 在孔的轴向方向上具有定向排列的开口孔隙, 这些开口孔隙的存在有利于植入初期新生组织的长入。覆盖在骨水泥基体表面的PLGA 膜可以增强基体的强度并弥补基体表面的缺陷, 充填在孔隙内部的PLGA 泡沫体可以很好地承受外加载荷, 使复合支架材料具有较好的强度和韧性。      

磷酸钙骨水泥/明胶复合组织工程支架材料的制备及其结构与性能

磷酸钙骨水泥组织工程支架材料具有良好的生物相容性和骨传导性,是一种良好的骨组织工程支架材料,但是这种材料存在力学性能差的缺点,限制了它的应用.本文采用生物相容性良好的可降解明胶材料与磷酸钙骨水泥支架进行复合,制备出的明胶/磷酸钙骨水泥复合支架材料,其压缩强度可达3.7MPa,比复合前磷酸钙支架材料的强度提高了37倍,而且材料具有良好的柔韧性,适合用作为非承重部位骨组织缺损修复用组织工程支架材料.     

可缓释药物的明胶/磷酸钙骨水泥复合组织工程支架材料

采用向孔隙中灌注含聚乳酸聚乙醇酸共聚物（PLGA）载药微球的明胶溶液的方法制备了具有药物缓释功能的明胶/磷酸钙骨水泥复合组织工程支架。用扫描电子显微镜观察了微球和支架的形貌特征,用万能材料试验机测定了支架材料的抗压强度,用紫外-可见分光光度计分析了复合支架的释药率。结果表明,灌注明胶对多孔磷酸钙骨水泥支架起到显著的增强作用,抗压强度达2.42 MPa。复合支架携载硫酸庆大霉素, 具有良好的药物缓释功能,缓释时间可达30天以上,使支架在修复骨缺损的同时能消除炎症反应,成为一种集骨修复和治疗于一体的新型组织工程支架材料,具有良好的应用前景。      

类生理环境下可降解纤维/磷酸钙复合骨水泥的性能与结构变化

采用生理盐水浸泡与肌肉埋植的方法分别研究了可降解纤维/磷酸钙复合骨水泥的体外力学性能、体内降解性能以及相组成、微结构随浸泡（或植入）时间的变化规律。浸泡结果表明:浸泡初期,纤维的加入一定程度上降低了复合骨水泥的抗压强度,但大大改善了其断裂韧性,而且抗弯强度略有增加;浸泡后期,复合骨水泥的抗压强度、抗弯强度、断裂功均明显下降。体内降解结果表明,随着植入时间延长,含纤维复合骨水泥的降解速率及其增加幅度均高于未掺纤维骨水泥。类生理环境下含纤维复合骨水泥力学性能、降解性能的变化与纤维的降解、材料微观结构的变化密切相关。      

含盐酸四环素α-TCP骨水泥的理化性能

对含有盐酸四环素的α-TCP骨水泥的理化性能进行了研究。盐酸四环素吸附和同钙离子螯合而结合到磷酸钙晶体表面,从而对磷酸钙骨水泥的水化过程产生影响。研究结果表明,盐酸四环素的加入一定程度上延长了骨水泥的凝结时间．但XRD分析显示并不影响α-TCP的最终的转化;同时改变了骨水泥固化体的晶体形貌和微结构,使形成的羟基磷灰石晶体由原来发散的针状晶转变为相互交织的条状和层状晶,这种晶体形貌的改变在一定盐酸四环素含量的条件下明显提高了骨水泥的抗压强度。     

磷酸钙骨水泥负载庆大霉素的制备与性能

制备了庆大霉素、磷酸钙骨水泥药物缓释体系,研究了药物缓释效果及载入庆大霉素对骨水泥组成、结构与性能的影响.结果表明,庆大霉素、磷酸钙骨水泥体系具有良好的药物缓释效果;随着庆大霉素的载入,骨水泥的凝结时间延长,但当载入量达到5%时,骨水泥的凝结时间又缩短至15 min,继续增大药物含量,凝结时间又略有延长.低载药量(1%)时骨水泥的抗压强度有所提高,但再继续增大载药量,体系的抗压强度又逐渐下降.庆大霉素的加入对骨水泥的最终水化产物没有明显影响,水化产物都是弱结晶的羟基磷灰石.庆大霉素的载入量为3%～5%时,庆大霉素/磷酸钙骨水泥缓释体系具有最佳的综合性能.     

多孔磷酸钙骨水泥组织工程支架的高分子灌注增强

利用棒状谷氨酸钠晶体作为造孔粒子,采用可溶盐造孔法,制备了三维连通的大孔径多孔磷酸钙骨水泥支架,分别将明胶(Gelatin) 、聚乳酸2羟基乙酸共聚物(PLGA) 、聚乳酸(PLA) 、聚己内酯(PCL) 、聚羟基丁酸戊酸酯(PHBV)灌注到多孔磷酸钙骨水泥(CPC)支架的孔隙中以改善支架材料的力学性能。结果表明,5 种高分子材料与水的接触角大小顺序为PHBV > PCL > PLA > PL GA > Gelatin , 复合支架材料的强度随高分子材料与水接触角的减小而增大;除PHBV外,其余4种均有明显的增强效果,其中Gelatin/CPC复合支架增强效果最好,强度达到2. 25 MPa±0. 02 MPa ,是CPC支架强度的25倍。经过增强的大孔径多孔磷酸钙骨水泥复合支架可用作骨组织工程支架材料。      

等静压处理对磷酸钙骨水泥结构和性能的影响

采用冷等静压技术,在150MPa的压力下对磷酸钙骨水泥粉体进行等静压处理,然后使其在一定的条件下进行水化.采用扫描电镜(Scanning electronmicroscope,SEM)、红外光谱(Fourier transform ininfrared spectrome-try,FTIR)、X射线衍射(X-ray diffraction,XRD)和压汞仪等测试手段对其水化产物的结构和性能进行研究.结果表明,经过等静压处理,磷酸钙骨水泥粉体水化环境被改变,部分水化产物的晶体形貌由细小的短棒状变为六棱柱状,但主要物相仍为羟基磷灰石;水化固化体的孔隙率由未经等静压处理时的(46.32±2.70)%降到(24.75±1.15)%,抗压强度由(12.62±2.70)MPa提高到(43.05±2.08)MPa.     

丝素蛋白/纳米生物玻璃复合多孔支架的结构与性能

采用冷冻干燥法制备了丝素蛋白(SF)/纳米生物玻璃(NBG)复合多孔支架材料。并用XRD、FT-IR、SEM等对SF/NBG复合支架进行了结构与性能表征。结果表明,SF/NBG复合多孔支架孔连通性较好,孔径为150～300μm,孔隙率为80.6%～90.3%;同时NBG的加入促进了复合多孔支架中SF的构象部分由无规卷曲向β-折叠转变。复合多孔支架抗压强度和抗压模量相比于纯SF多孔支架有较大提高。采用模拟体液浸泡实验研究了复合支架的体外生物活性,并用XRD、FT-IR和FESEM对试样表面进行了表征。结果显示,复合多孔支架经模拟体液浸泡7d后,表面沉积出类骨羟基磷灰石(HA)层,NBG的加入能加快复合多孔支架表面沉积类骨HA的速度。研究结果显示SF/NBG复合多孔支架材料有望作为生物活性良好的骨组织修复材料。     

磷酸钙骨水泥大孔径多孔组织工程支架的制备及其纤维增强

采用粒子溶出造孔法, 用棒状谷氨酸钠晶体作为造孔粒子, 制备磷酸钙骨水泥多孔支架, 研究了造孔粒子含量和多孔支架孔隙率之间的关系, 并加入甲壳素纤维来改善支架材料的力学性能. 结果表明, 支架材料的孔隙率可达(79.8±2.3)%,孔隙直径100～600μm; 复合纤维后支架的强度提高了3～4倍, 断裂应变显著提高, 可作为非承重部位骨缺损修复的骨组织工程支架材料.     

新型可降解钙磷骨水泥多孔支架研究

采用一种特殊的方法制备了孔径、孔隙率和孔形状可控的多孔羟基磷灰石骨水泥支架. 材料的抗压强度可达4MPa, 孔隙率可达70%, 孔与孔之间互相贯通, 大孔壁富含微孔. 细胞在材料表面黏附铺展且增殖良好, 体外模拟实验显示材料的降解速度随孔隙率的增加和Ca/P比的降低而加快, 多孔支架有优良的生物降解性和生物相容性. 该材料可用于修复骨组织缺损和作为支架材料用于组织工程.     

机械活化增强多孔磷酸钙骨水泥支架的研究

本研究采用球磨对磷酸钙骨水泥(CPC)起始粉末进行机械活化处理, 以期改善CPC力学性能, 并探讨了其影响机理。采用激光粒度仪、比表面积测量仪和X射线衍射仪(XRD)表征球磨后的CPC粉末(Ball milling CPC, BCPC)。利用发泡法制备多孔BCPC支架, 采用万能力学试验机、XRD和扫描电子显微镜(SEM)表征多孔BCPC支架。结果显示, 球磨后的BCPC粉末平均粒径减小, 比表面积增大, 表观密度、堆积密度及紧密密度减小。BCPC支架孔隙率为(77.98 ± 0.58)%, 抗压强度为(4.11 ± 0.46) MPa, 相比CPC支架的(64.23 ± 2.32)%和(1.99 ± 0.43) MPa有显著提高。SEM结果显示BCPC支架具有数微米和数百微米的两种孔隙结构。XRD结果表明机械活化作用降低了DCPD、α-TCP、CaCO₃和HA的晶粒尺寸和结晶度, 促使DCPD向DCPA转化, 促进了各相磷酸钙盐的水化和HA的沉积, 提高了BCPC支架的力学性能, 为增强CaP基多孔材料的力学性能和扩展其临床应用提供了新途径。     

Morphological,mechanical, and biocompatibility characterization of macroporous alumina scaffolds coated with calcium phosphate/PVA

In bone tissue engineering, a highly porous artificial extracellular matrix or scaffold is required to accommodate cells and guide the tissue regeneration in three-dimension. Calcium phosphate (CaP) ceramics are widely used for bone substitution and repair due to their biocompatibility, bioactivity, and osteoconduction. However, compared to alumina ceramics, either in the dense or porous form, the mechanical strength achieved for calcium phosphates is generally lower. In the present work, the major goal was to develop a tri-dimensional macroporous alumina scaffold with a biocompatible PVA/calcium phosphate coating to be potentially used as bone tissue substitute. This approach aims to combine the high mechanical strength of the alumina scaffold with the biocompatibility of calcium phosphate based materials. Hence, the porous alumina scaffolds were produced by the polymer foam replication procedure. Then, these scaffolds were submitted to two different coating methods: the biomimetic and the immersion in a calcium phosphate/polyvinyl alcohol (CaP/PVA) slurry. The microstructure, morphology and crystallinity of the macroporous alumina scaffolds samples and coated with CaP/PVA were characterized by X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM/EDX) analysis. Also, specific surface area was assessed by BET nitrogen adsorption method and mechanical behavior was evaluated by axial compression tests. Finally, biocompatibility and cytotoxicity were evaluated by VERO cell spreading and attachment assays under SEM. The morphological analysis obtained from SEM photomicrograph results has indicated that 3D macroporous alumina scaffolds were successfully produced, with estimated porosity of over 65% in a highly interconnected network. In addition, the mechanical test results have indicated that porous alumina scaffolds with ultimate compressive strength of over 3.0 MPa were produced. Concerning to the calcium phosphate coatings, the results have showed that the biomimetic method was not efficient on producing a detectable layer onto the alumina scaffolds. On the other hand, a uniform and adherent inorganic–organic coating was effectively formed onto alumina macroporous scaffold by the immersion of the porous structure into the CaP/PVA suspension. Viable VERO cells were verified onto the surface of alumina porous scaffold samples coated with PVA–calcium phosphate. In conclusion, a new method was developed to produce alumina with tri-dimensional porous structure and uniformly covered with a biocompatible coating of calcium phosphate/PVA. Such system has high potential to be used in bone tissue engineering.     

Needle-like nano hydroxyapatite/poly(l-lactide acid) composite scaffold for bone tissue engineering application

In this paper, a new nano-hydroxyapatite / poly (l-lactide acid) (nHAP/PLLA) composite scaffold comprising needle-like nHAP particles was prepared. In the first step, the identification and morphology of chemically synthesized HAP particles were determined by XRD, EDX, FTIR and SEM analyses. The needle-like nHAP particles with an average size of approximately 30–60 nm in width and 100–400 nm in length were found similar to needle-like bone nano apatites in terms of chemical composition and morphology. In the second step, nHAP and micro-sized HAP (mHAP) particles were used to fabricate HAP filled PLLA (HAP/PLLA) composites scaffolds using solid–liquid phase separation method. The porosity of scaffolds was up to 85%, and their average macropore diameter was in the range of 64–175 µm. FTIR and XRD analyses showed the presence of molecular interactions and chemical linkages between HAP particles and PLLA matrix. The compressive strength of nanocomposite scaffolds could high up to 8.46 MPa while those of pure PLLA and microcomposite scaffolds were 1.79 and 4.61 MPa, respectively. The cell affinity and cytocompatibility of the nanocomposite scaffold were found to be higher than those of pure PLLA and microcomposite scaffolds. Based on the results, the newly developed nHAP/PLLA composite scaffold is comparable with cancellous bone in terms of microstructure and mechanical strength, so it may be a suitable alternative for bone tissue engineering applications.     

介孔生物活性玻璃/脱钙骨复合支架的制备及性能研究

将介孔生物活性玻璃(MBG)与脱钙骨(DB)复合, 利用浸渍法制备出MBG/DB复合支架材料. 采用红外光谱(FTIR), 扫描电镜(SEM), X射线衍射(XRD), 电子万能材料试验机等方法对牛松质骨(CB)、DB、MBG/DB复合支架进行表征. 结果表明, CB经浸酸处理后制备的DB, 孔径大小在200~600μm范围内, 孔隙率约为71%, 抗压性能比CB明显降低(1.10±0.31)MPa, 而采用浸渍法制备的复合支架, 孔隙率降为40%左右, 而压缩强度明显提高(8.49± 2.14)MPa. 体外生物活性测试表明: 复合支架具有良好的生物活性.