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。      

磷酸钙/纤维蛋白胶复合支架材料的结构及力学性能分析

用可吸收磷酸钙骨水泥和纤维蛋白胶按一定比例体外构建复合支架材料,通过XRD、SEM、抗压实验和空隙率测试等方法对其结构及力学性能进行分析.结果发现:由于加入纤维蛋白胶,复合支架材料在一定程度上延长了磷酸钙骨水泥的初凝时间,但并不影响磷酸钙骨水泥的终凝时间;同时,加入纤维蛋白胶改变了骨水泥固化体的微观结构,提高了骨水泥的抗压强度,其最大抗压强度达到14MPa,弹性模量在96.64～269.39MPa之间,空隙率为38.8%.与在同样条件下制备的磷酸钙骨水泥比较,复合支架材料的抗压强度增强了55.6%,而空隙率仅仅下降了6.9%;XRD分析显示,复合支架材料并不影响磷酸钙骨水泥的最终的转化,其结晶结构仍是羟基磷灰石结构,是更好的骨组织工程支架材料.     

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。      

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.     

可注射磷酸钙骨水泥复合材料研究进展

研制既具有多孔结构又具有足够力学强度的磷酸钙骨水泥材料是当前骨修复材料研究的热点之一。报道了研制的磷酸钙骨水泥复合材料,在植入初期具有较高的力学强度,植入后可渐渐降解成孔,为骨修复材料的研究提供了新的方法和途径。磷酸钙骨水泥复合材料以磷酸钙骨水泥为基体,在基体中加入具有生物降解性的微球形成复合材料,保证了复合材料植入初期有足够力学强度为新生组织提供支撑,防止自身的坍塌,而具有生物降解性微球的降解速度比磷酸钙骨水泥的固化体快,随着微球的降解在磷酸钙骨水泥基体中就会产生很多三维孔隙,利于细胞粘附生长,血管和神经长入,以及营养成分的渗入和代谢产物排出。这种结构设计使可体内降解成孔的磷酸钙骨水泥既具有足够力学强度又具有多孔结构,还可以通过改变不同材料的比例来调节复合材料的初始力学强度和降解速度。目前已研制成功了壳聚糖微球/磷酸钙骨水泥复合材料、聚羟基丁酸—戊酸酯(PHBV)/磷酸钙骨水泥复合材料,其凝固时间为10～15min,抗压强度达到30～40MPa,孔隙率70%～80%,孔径分布为100～300μm,并对复合材料的降解性、细胞相容性和动物体内植入试验进行了研究,表明所研制的材料具有良好的生物相容性,可降解性和成...     

壳聚糖/磷灰石-硅灰石复合多孔支架材料的制备与性能

以磷灰石-硅灰石(AW)生物活性多孔玻璃陶瓷支架材料为基体,采用物理包被法制备了壳聚糖(CS)/AW复合多孔支架材料,通过红外图谱分析、扫描电镜、光学显微镜、强度检测等分析测试方法,研究了复合材料的组成、微观结构、力学和矿化性能。结果发现：复合材料与AW多孔支架材料基体相比,仍具有三维贯通且分布均匀的孔隙结构,孔径尺寸约 100～500μm,孔隙率为80%左右,且力学性能明显增强,平均抗压强度可达3.11 MPa,比多孔AW支架材料基体的平均抗压强度提高了8.3倍。体外模拟体液浸泡实验表明,复合材料具有较高的矿化功能,预示材料具有较好的生物活性。这种复合材料可望作为人体非承重部位的植入骨修复体和组织工程支架使用。     

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.     

β-CaSiO_3/丝素蛋白复合支架材料结构与性能的研究

利用冷冻干燥法制备了β-CaSiO_3/丝素蛋白复合支架材料,经XRD和FTIR分析表明复合支架中丝素的结构主要以β-折叠为主;SEM分析显示材料孔隙分布均匀,孔连通性较好,孔径尺寸约为100～300μm.对支架的孔隙率和机械强度等性能进行了表征,研究表明复合支架的孔隙率为83%～87%,机械强度有较大提高.应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、FESEM和EDS对试样表面进行了表征;结果显示,样品经模拟体液浸泡3天后,表面都能沉积出类骨羟基磷灰石(HA)层,β-CaSiO_3的加入能加快复合支架表面沉积类骨HA的速度.研究结果显示β-CaSiO_3/丝素蛋白复合支架材料有望作为强度较好的生物活性硬组织修复材料.     

磷酸钙骨粘合剂的研究

在柠檬酸中添加壳聚糖配成的固化液与磷酸钙骨水泥(CPC)调和制备的骨修复材料具有类似口香糖的胶状特性, 可应用于碎骨粘结, 称之为磷酸钙骨粘合剂(CPCBA)。本研究考察了柠檬酸的含量对抗压强度、固化时间、水化产物和粘结强度的影响, 同时对该体系进行了初步的体外生物学评价。结果显示, 加入柠檬酸可以缩短固化时间并且时间可以通过柠檬酸的含量进行调控, 同时也改善了抗水性能。壳聚糖可以与骨水泥中的钙离子发生螯合作用, 可以增加界面的粘结强度。小鼠原成骨细胞(MC3T3-E1)在其表面粘附良好, 该体系骨水泥有望取代PMMA成为新的骨粘结剂。     

新型骨-软骨一体化修复支架材料的制备

利用可降解聚合物微球的相互粘结制备了一种新型的组织工程支架材料, 可用于软骨和软骨下骨损伤的修复。采用光学显微镜、 扫描电镜对支架的表面形貌、 内部结构进行了表征, 同时研究了支架材料的力学性能, 此外还研究了微球的粒径对支架材料孔隙率的影响。结果显示, 该材料在结构上分为乳酸-羟基乙酸共聚物(PLGA)层和PLGA/生物活性玻璃(BG)层; 材料的孔隙三维连通、 分布均匀; 采用粒径为150~200μm微球所制备的支架孔隙率为(53.37±4.39)%, 在10%的应变下材料压缩强度便已达到了0.9MPa, 显示了较强的力学性能; 随着微球粒径的变小, 材料孔隙率逐渐增大。这种微球支架在骨-软骨组织缺损修复方面有着很大的研究价值和应用价值。      

Fabrication and cell affinity of biomimetic structured PLGA/articular cartilage ECM composite scaffold

An ideal scaffold for cartilage tissue engineering should be biomimetic in not only mechanical property and biochemical composition, but also the morphological structure. In this research, we fabricated a composite scaffold with oriented structure to mimic cartilage physiological morphology, where natural nanofibrous articular cartilage extracellular matrix (ACECM) was used to mimic the biochemical composition, and synthetic PLGA was used to enhance the mechanical strength of ACECM. The composite scaffold has well oriented structure and more than 89% of porosity as well as about 107 μm of average pore diameter. The composite scaffold was compared with ACECM and PLGA scaffolds. Cell proliferation test showed that the number of MSCs in ACECM and composite scaffolds was noticeably bigger than that in PLGA scaffold, which was coincident with results of SEM observation and cell viability staining. The water absorption of ACECM and composite scaffolds were 22.1 and 10.2 times respectively, which was much higher than that of PLGA scaffolds (3.8 times). The compressive modulus of composite scaffold in hydrous status was 1.03 MPa, which was near 10 times higher than that of hydrous ACECM scaffold. The aforementioned results suggested that the composite scaffold has the potential for application in cartilage tissue engineering.     

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.     

Bi-layered calcium phosphate cement-based composite scaffold mimicking natural bone structure

Abstract

In this study, a core/shell bi-layered calcium phosphate cement (CPC)-based composite scaffold with adjustable compressive strength, which mimicked the structure of natural cortical/cancellous bone, was fabricated. The dense tubular CPC shell was prepared by isostatic pressing CPC powder with a specially designed mould. A porous CPC core with unidirectional lamellar pore structure was fabricated inside the cavity of dense tubular CPC shell by unidirectional freeze casting, followed by infiltration of poly(lactic-co-glycolic acid) and immobilization of collagen. The compressive strength of bi-layered CPC-based composite scaffold can be controlled by varying thickness ratio of dense layer to porous layer. Compared to the scaffold without dense shell, the pore interconnection of bi-layered scaffold was not obviously compromised because of its high unidirectional interconnectivity but poor three dimensional interconnectivity. The in vitro results showed that the rat bone marrow stromal cells attached and proliferated well on the bi-layered CPC-based composite scaffold. This novel bi-layered CPC-based composite scaffold is promising for bone repair.     

纳米羟基磷灰石/聚己内酯复合生物活性多孔支架研究

采用水热法制备了纳米羟基磷灰石（n-HA）及其与聚己内酯（PCL）的复合材料. 用熔融浇铸/食盐微粒浸出法制备了孔径在200～400μｍ、大孔互相贯通的复合材料支架. 通过细胞培养和体内动物实验研究了该支架的生物学性能. 结果表明,复合支架的孔隙率随致孔剂用量的增加而增加,而抗压强度随之而减小;支架的最大孔隙率可达86%,相应的抗压强度为2.4MPa. 成骨细胞在支架上的细胞粘附率和增殖随磷灰石含量增加而提高,复合材料明显高于单纯的PCL支架. 组织学观察显示,新生骨长入多孔支架和复合材料形成了直接的骨性结合. n-HA/PCL复合材料支架有很好的生物相容性和生物活性.     

Preparation of PLGA/β-TCP composite scaffolds with supercritical CO 2 foaming technique

A high porosity scaffold with suitable compressive strength prepared by a gentle method has become a pressing need. To meet this demand, poly(DL-lactide-co-glycolide) (PLGA) and β-tricalcium phosphate (β-TCP) were designed to prepare composite scaffolds by the supercritical technique. The preparation process consisted of three units: the mixing of PLGA and β-TCP, compression molding of the mixture, and the foaming process. Six influencing factors — temperature, pressure of the scCO₂ system, maintaining time of scCO₂, the ratio of β-TCP to PLGA, the rate of depressurization, and the molecular weight — were investigated. The results collectively indicated that the optimized conditions for the foaming process were that CO₂ pressure and temperature be 8MPa and 39°C, respectively, which should be kept for 8h; the content of β-TCP in the mixture should be 25% and the depressurizing rate be 0.1 MPa/s, using PLGA of an 80kDa molecular weight. Scaffolds with a porosity of 65.47% and a compressive strength of 4.76 MPa could be obtained. The pore size ranged around 100 µm. The material’s use as tissue engineering scaffolding is expected.     

浆料粘度对纳米羟基磷灰石/聚酰胺66复合支架孔结构与力学性能的影响

浆料粘度是热诱导相分离法制备支架材料的关键因素,采用不同粘度的纳米羟基磷灰石/聚酰胺66(n-HA/PA66)复合浆料制备了相应的n-HA/PA66多孔支架,并对不同粘度浆料制备支架材料的泡孔结构和力学性能等进行了对比研究。结果表明,浆料粘度对n-HA/PA66复合多孔支架的孔径、孔径分布、孔隙率、开孔率、力学强度等性能有显著的影响。随着浆料粘度的增大,制备支架的孔径、孔隙率、开孔率逐渐减小,而力学强度却逐渐增大。当浆料粘度为330Pa.s时,制备出的n-HA/PA66复合多孔支架综合性能最好,其孔径主要分布在200～500μm,平均孔径(324±67.1)μm,孔隙率为(75±1.6)%,开孔率为(59±2.5)%,抗压强度为(2.12±0.90)MPa,能够较好地满足骨组织工程支架材料对孔径、孔隙率和力学性能的要求。     

Fabrication of three dimensional polymeric scaffolds with spherical pores

This paper reports polymeric scaffolds with spherical internal macropores and relatively large external dimension. Paraffin spheres with the diameter of several hundred microns were prepared by a suspension technique. Particulate leaching technique based on this kind of spherical porogens was combined with room-temperature compression molding technique to fabricate biodegradable poly(D,L-lactic-co-glycolic acid) (PLGA) porous scaffolds potentially for tissue engineering or in situ tissue induction. The scaffolds exhibited ordered macropores with good pore interconnectivity. The porosity ranged from 80 to 97% adjusted simply by varying porogen content. The foams with porosity around 90% have compressive modulus over 3 MPa and compressive strength over 0.2 MPa. As preliminary cell experiments with 3T3 fibroblasts cultured on the porous scaffolds indicate, the processing procedure of the scaffolds has not brought with problem in cytotoxicity.