羟基磷灰石含量对纳米粒子-聚己内酯复合材料性能的影响

水热法合成纳米羟基磷灰石(HA)并将其分散在己内酯中,以其羟基为引发剂,在催化剂的作用下,引发己内酯开环聚合,制备纳米粒子-聚合物复合材料.NMR、DSC、XRD、PLM以及力学性能试验,探讨纳米粒子含量对复合材料的性能影响.随着纳米粒子含量的增加,聚己内酯(PCL)聚合度逐渐降低,在较高HA含量时,仍然存在较多的纳米粒子团聚;复合材料中PCL的结晶度基本不随纳米HA含量的变化而变化;HA含量为5wt%时,复合材料的断裂延伸率、抗拉强度以及压缩模量达到最大值;HA含量低于20wt%时,复合材料的弹性模量随着纳米粒子含量的增大而增加.     

高链玉米淀粉对聚己内酯组织工程支架材料结构与性质的影响

采用高链玉米淀粉改性聚己内酯（PCL）,通过溶剂浇铸/粒子沥滤法制备聚己内酯/淀粉（SPCL）组织工程支架;考察了改性后支架材料的化学结构、结晶性、亲水性和细胞相容性.结果表明,适量淀粉的引入能够降低支架材料的结晶性、改善材料的亲水性和细胞相容性,70％PCL/30％淀粉支架材料的细胞粘附率、增殖率和细胞活性为最佳,有望应用在骨组织工程中.     

羟基磷灰石/聚己内酯生物复合材料的制备及其生物活性

以聚己内酯(PCL)为基底、羟基磷灰石(HA)为增强剂,采用溶液浇铸法制备HA/PCL复合材料,考察了浸渍于模拟体液(SBF)中的复合材料生物活性,并用X衍射(XRD)和傅立叶变换红外光谱(FT IR)对材料的结构和组成进行表征。结果表明:HA/PCL(wHA=0.30)复合材料在SBF中浸渍14 d后,即在其表面形成一层弱结晶的碳磷灰石(CHA)覆盖层,显示良好的生物活性。     

原位制备聚己内酯和羟基磷灰石复合材料

采用溶胶-凝胶技术和真空干燥技术,原位制备了聚己内酯(PCL)和羟基磷灰石(HAP)多孔复合材料.对样品进行扫描电镜(SEM)、X射线粉末衍射仪(XRD)和拉曼散射光谱(Raman)表征和分析.结果表明,羟基磷灰石与聚己内酯分子间存在弱氢键作用;当羟基磷灰石在复合材料中的质量分数低于40％时,没有明显的相分离现象出现.     

3D打印PLLA/HA复合组织工程骨支架及性能表征

为了解决羟基磷灰石(HA)骨支架降解难的问题,本研究通过在HA骨支架中加入具有良好降解性能的聚左旋乳酸(PLLA)来调节其降解速度.采用3D打印挤出成型设备制备出PLLA/HA复合多孔骨支架,探究不同PLLA质量分数下复合组织工程骨支架抗压强度、亲水性、降解率以及细胞毒性的变化.实验结果表明:五组不同材料配比的复合骨支...     

纳米羟基磷灰石/己内酯/丙交酯共聚物的合成和结晶行为

以辛酸亚锡为催化剂,通过针状纳米羟基磷灰石(HA)的-OH引发ε-己内酯(ε-CL)开环聚合,再接枝不同量的丙交酯(D,LLA),制备了HA-PCL-PLA复合材料.用傅里叶变换红外光谱、X射线衍射、差示扫描量热法等对聚合物的结构进行表征.红外测试结果表明,样品的结晶度大致相同,且结晶度都不高;而DSC的测试结果表明,HA-PCL-PLA体系中的PCL比纯PCL呈现低的结晶度,PCL的结晶受到了限制,D,LLA的加入阻碍了ε-CL的结晶.PLM测试显示同等温度下PCL球晶大小随着D,LLA质量的增加而增大,D,LLA的接枝可以显著改变PCL的结晶形态.     

nHA/PCL复合材料对成骨细胞增殖的影响

研究了纳米羟基磷灰石/聚己内酯(nHA/PCL)复合材料对成骨细胞的增殖的影响.制备了3种不同的nHA/PCL材料浸提液(3种材料中nHA/PCL质量比分别为0∶100,20∶80和40∶60).采用四唑盐比色法(MTT)检测不同的nHA/PCL材料浸提液对成骨细胞增殖率的影响.应用流式细胞术检测复合材料对成骨细胞周期的影响.结果表明:与对照组相比,实验组细胞增殖率和细胞各时期细胞数量均无显著性差异(p>0.05);研究表明:nHA/PCL浸提液对成骨细胞的增殖无不良影响,具有良好的细胞的相容性,其中40%nHA/PCL具有促进成骨细胞增殖指数的作用.     

纳米HA-PCL复合生物材料的结晶行为研究

通过针状纳米羟基磷灰石(HA)的-OH引发ε-己内酯(ε-CL)开环聚合,制备了HA-PCL复合生物材料,通过FTIR、XRD、DSC及PLM考察了HA对PCL结晶行为的影响。研究结果表明:HA的加入对PCL起到结晶成核促进作用,但限制了PCL的结晶,使之比纯PCL呈现低的结晶度,而且除HA质量分数为1%的HA-PCL中的PCL可以在45℃形成消光黑十字球晶之外,其他样品在实验温度下只能形成细小的晶粒;另外,HA质量分数的变化对PCL的结晶度和结晶晶型的影响不明显。     

聚己内酯/介孔二氧化硅杂化材料的制备及表征

利用环氧丙醇对介孔二氧化硅SBA-15的表面进行碳羟基修饰,然后以此为引发剂,异辛酸亚锡为催化剂,分别引发己内酯（CL）及氨基甲酸苄基酯-ε-己内酯(（CABCL）单体的开环聚合,成功地制备了杂化材料聚己内酯/SBA-15（PCL/SBA-15）和聚4-氨基甲酸苄基酯己内酯/SBA-15（PCABCL/SBA-15）,酸解去除PCABCL/SBA-15的保护基团甲酸苄酯（Cbz）后得到聚氨基己内酯/SBA-15（PACL/SBA 15）。通过X射线衍射仪（XRD）、N₂吸附-脱附实验和热重分析（TGA）等手段研究了材料的结构变化、反应时间和空间位阻效应对接枝量的影响等。结果表明:聚合物的修饰未对介孔结构产生影响;PCL的接枝量可以通过聚合反应时间进行控制;对PACL/SBA-15而言,因CABCL中Cbz的位阻效应导致接枝量较小;Zeta电位分析的结果证明聚氨基己内酯的修饰改变了二氧化硅表面的电荷性质。     

羟基化碳纳米管/聚己内酯复合材料的结构和力学性能!

将羟基化多壁碳纳米管在超声波作用下均匀分散于己内酯单体中,通过原位微波辅助开环聚合的方法制备了聚己内酯/羟基化多壁碳纳米管复合材料.羟基化多壁碳纳米管的引入明显提高了聚己内酯材料的强度和模量,但是断裂伸长率却随着羟基化多壁碳纳米管含量的增加而持续降低.羟基化多壁碳纳米管的质量分数为0.5%时,纳米复合材料的拉伸强度和杨氏模量可提高至纯聚己内酯材料的2倍.利用扫描电镜、X线衍射、红外光谱和示差扫描量热分析揭示了纳米复合材料断裂形貌、结晶情况和热性质,进而探讨了羟基化多壁碳纳米管对提高力学性能的作用机制.     

Dexamethasone-Loaded PLGA Microspheres Incorporated PLLA/PLGA/PCL Composite Scaffold for Bone Tissue Engineering

The combination of micro-carriers and polymer scaffolds as promising bone grafts have attracted considerable interest in recent decades.The poly(L-lactic acid)/poly(lactic-co-glycolic acid)/polycaprolactone(PLLA/PLGA/PCL)composite scaffold with porous structure was fabricated by thermally induced phase separation(TIPS).Dexamethasone(DEX)was incorporated into PLGA microspheres and then loaded on the PLLA/PLGA/PCL scaffoldtopreparethedesiredcompositescaffold.The physicochemical properties of the prepared composite scaffold were characterized.The morphology of rat bone marrow mesenchymal stem cells(BMSCs)grown on scaffolds was observed using scanning electron microscope(SEM)and fluorescence microscope.The resultsshowedthatthePLLA/PLGA/PCLscaffoldhad interconnected macropores and biomimetic nanofibrous structure.In addition,DEX can be released from scaffold in a sustained manner.More importantly,DEX loaded composite scaffold can effectively support the proliferation of BMSCs as indicated by fluorescence observation and cell proliferation assay.The results suggested that the prepared PLLA/PLGA/PCL composite scaffold incorporating drug-loaded PLGA microspheres could hold great potential for bone tissue engineering applications.     

Strontium Substituted Nanohydroxyapatite Incorporated 3D Printing Scaffold for Bone Tissue Engineering

The customized implants which are composed of polycaprolactone( PCL) and strontium substituted nanohydroxyapatite( SrHA) were fabricated successfully by using fused deposition modeling( FDM),which is a simple 3 D printing technology for fabricating personalized products. The physical and chemical properties of composite scaffolds were characterized by transmission electron microscopy( TEM), Fourier transform infrared spectroscopy( FTIR), X-Ray diffraction( XRD) and inductively coupled plasma-atomic emission spectroscopy( ICPAES). The results suggested that strontium element was successfully doped into nanohydroxyapatite and all scaffolds showed the homogeneous network structure. Furthermore, the in vitro biocompatibility of the scaffolds was evaluated by cell counting kit-8( CCK-8) assay. The data indicated that the prepared scaffolds exhibited excellent biocompatibility to bone marrow mesenchymal stem cells( BMSCs). Besides,strontium element can be released from PCL-SrHA scaffolds in a sustained manner. Therefore,the 3 D printing PCL-SrHA scaffolds hold great potential for bone tissue engineering.     

Fabrication and characterization of 3D scaffold using 3D plotting system

In this paper, we design and fabricate a 3D scaffold using rapid prototyping (RP) technology for tissue engineering. The scaffold should have a three-dimensional interconnected pore network. We fabricate a polycaprolactone (PCL) scaffold with interconnecting pores and uniform porosity for cell ingrowth using a 3D plotting system. In order to keep the three dimensional shape under mechanical loading while implanted, we design an oscillating nozzle system to increase elastic modulus and yield strength of PCL ...     

骨组织工程用纳米羟基磷灰石／细菌纤维素的体外降解行为研究

将细菌纤维素浸泡在模拟体液中沉积而形成的纳米羟基磷灰石／细菌纤维素复合材料（nano-HA／BC）,被认为是在骨组织工程领域中理想的支架材料。从以下几方面分析nano-HA／BC在磷酸盐缓冲液（PBSl中浸泡不同时间后的降解行为及其相应的机制：材料的降解程度、nano．HA颗粒的稳定性和BC的结构变化。结果表明,nano-HA／BC在PBS溶液中浸泡-定时间后,nano-HA颗粒会逐渐溶解或脱落,水分子直接与BC纤维丝相互作用。在水分子和离子的作用下,BC的结晶度降低,BC分子链中分子间和分子内的结合力降低,甚至部分非结晶区内C-O-C键断裂。而C-O-C键的断裂是nHA／BC在PBS溶液中BC大分子降解的主要机制。研究结果对于研究骨组织工程支架材料nHA／BC的体内降解行为具有重要的指导意义。     

Engineered polycaprolactone – magnesium hybrid biodegradable porous scaffold for bone tissue engineering

In this paper, we describe the fabrication of a new biodegradable porous scaffold composed of polycaprolactone(PCL) and magnesium(Mg)micro-particles. The compressive modulus of PCL porous scaffold was increased to at least 150% by incorporating 29% Mg particles with the porosity of 74% using Micro-CT analysis. Surprisingly, the compressive modulus of this scaffold was further increased to at least 236% when the silane-coupled Mg particles were added. In terms of cell viability, the scaffold modified with Mg particles significantly convinced the attachment and growth of osteoblasts as compared with the pure PCL scaffold. In addition, the hybrid scaffold was able to attract the formation of apatite layer over its surface after 7 days of immersion in normal culture medium, whereas it was not observed on the pure PCL scaffold. This in vitro result indicated the enhanced bioactivity of the modified scaffold. Moreover, enhanced bone forming ability was also observed in the rat model after 3 months of implantation. Though bony in-growth was found in all the implanted scaffolds. High volume of new bone formation could be found in the Mg/PCL hybrid scaffolds when compared to the pure PCL scaffold. Both pure PCL and Mg/PCL hybrid scaffolds were degraded after 3 months. However, no tissue inflammation was observed. In conclusion, these promising results suggested that the incorporation of Mg micro-particles into PCL porous scaffold could significantly enhance its mechanical and biological properties. This modified porous bio-scaffold may potentially apply in the surgical management of large bone defect fixation.     

几种骨组织工程复合支架材料在模拟生理溶液中的生物矿化性能比较

采用生物活性玻璃(BG)、磷酸三钙(TCP)、羟基磷灰石(HA)等生物活性陶瓷与3-羟基丁酸酯-3-羟基戊酸酯的共聚物(PHBV)复合,制备了性能良好的骨组织工程支架材料,分析了PHBV/BG,PHBV/TCP,PHBV/HA三种复合多孔支架在模拟生理溶液中的一系列化学反应,以及多孔材料在模拟生理溶液中浸泡后的成分、结构和微观形貌的变化.研究结果表明,三种复合支架材料在模拟生理溶液中发生了降解反应而失重;PHBV/BG和PHBV/TCP在模拟生理溶液中还发生了生物矿化反应,在表面形成矿化沉积层,为具有骨生物活性的结晶态类骨碳酸羟基磷灰石;而PHBV/HA在模拟生理溶液中没有明显的生物活性反应.     

造孔粒子形貌对磷酸钙骨水泥支架材料结构与性能的影响

采用可溶粒子造孔法,结合冷等静压成型技术,分别以立方体的氯化钠晶体和短棒状的谷氨酸钠晶体为造孔粒子制备出具有较高孔隙率和良好抗压强度的磷酸钙骨水泥组织工程支架材料,通过X射线衍射分析、扫描电镜分析及力学性能测试,研究了所制备的支架材料的物相组成及颗粒形貌对支架材料显微结构和力学性能的影响.结果表明:两种造孔粒子制得的支架材料的主晶相均是弱结晶的羟基磷灰石;造孔粒子的形貌决定了所制备的支架的孔隙形貌,并影响支架的孔隙率和力学性能;在造孔粒子加入量相同的情况下,谷氨酸钠晶体作为造孔粒子制备的支架的孔隙率更高,但强度更低;由于在制备过程中引入了等静压处理,支架材料具有良好的强度.     

可溶粒子形貌对磷酸钙骨水泥支架结构和性能的影响

采用可溶粒子造孔法，结合冷等静压成型技术，分别用立方体的氯化钠晶体和短棒状的谷氨酸钠晶体两种不同形貌的造孔粒子制备出具有较高孔隙率和良好抗压强度的磷酸钙骨水泥组织工程支架材料，研究了颗粒形貌对支架材料的显微结构和力学性能的影响。结果表明，造孔粒子形貌决定了制备的磷酸钙骨水泥组织工程支架的孔隙形貌，并影响支架的孔隙率和力学性能。对于相同的加入量，谷氨酸钠晶体作为造孔粒子制备的支架的孔隙率高于氯化钠晶体制备的支架，而用氯化钠造孔粒子制备的支架的强度高于用谷氨酸钠造孔粒子制备的支架。由于在制备过程中引入了等静压处理，支架材料具有良好的强度。     

On Modeling Bio-Scaffolds: Structural and Fluid Transport Characterization Based on 3-D Imaging Data

Bio-scaffolds which are most commonly open celled porous structures are increasingly used for tissue engineering and regenerative medicine. A number of studies have shown that the bulk properties of such irregular structures are poorly modeled using idealized unit cell approaches. The paper therefore uses novel image based meshing techniques to explore both fluid flow and bulk structural properties of a bone scaffold, as accurate modeling of bio-scaffolds with non-uniform cellular structures is very important for the development of optimal scaffolds for tissue engineering application. In this study, a porous hydroxyapatite/tricalcium phosphate (HA/TCP) bone scaffold has been scanned in a Micro-CT scanner, and converted into a volumetric mesh using image processing software developed by the authors. The resulting mesh was then exported to commercial FEA and CFD solvers for analysis. Initial FEA and CFD studies have shown promising results and have highlighted the importance of accurate modeling to understand how microstructures influence the mechanical property of the scaffold, and to analyze flow regimes through the sample. The work highlights the potential use of image based meshing for the ad hoc characterization of scaffolds as well as for assisting in the design of scaffolds with tailored strength, stiffness, and transport properties.