纳米HAP/CPP/PLLA骨组织工程支架复合材料降解特性

现有支架材料的降解速率与骨细胞生长、繁殖速率不匹配,在降解过程中支架材料的强度、刚度衰减速率与成骨速率不匹配,支架材料在体内降解的酸性副产物会引起炎症反应.为克服以上困难,采用溶媒浇铸、颗粒滤取与气体发泡相结合的方法制备出纳米HAP/CPP/PLLA骨组织工程支架复合材料;选用生理盐水作为模拟体液进行降解实验,测试该支架复合材料的降解性能,用扫描电子显微镜对其在不同降解时期的微观结构进行观察.结果表明:纳米HAP/CPP/PLLA支架复合材料在降解过程中具有三维、连通、微孔网状结构,并具有良好的降解性能和生物相容性,是比较理想的骨组织工程支架材料.     

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...     

组织工程用β-磷酸三钙/聚乳酸支架材料性能评价

研究了β-磷酸三钙／聚乳酸（PLLA）叠层复合支架在体外37℃生理盐水中降解过程，结果表明复合材料的孔径为100－400μm、孔率在60％－70％以上；复合材料的降解环境酸度维持在近中性，而纯聚乳酸为3．0左右；复合材料失重百分离介于纯聚乳酸和β－磷酸三钙之间，在16周内达20％；随降解时间延长，复合材料力学强度下降、聚乳酸相对分子质量减小；降解过程中Ca^2 浓度在12周达最大，为0．002mol/L。证实该材料理化特性适合于骨组织工程支架材料的要求。     

钛种植体表面构筑多级微/纳米活性结构的研究

经喷砂的钛基体在H2SO4和HCl混合溶液中进行酸蚀,随后在HF溶液中恒电压下进行阳极氧化,构筑具有多级微/纳米复合结构膜层,并对不同表面处理样品进行体外实验,观察其生物活性.利用扫描电子显微镜(SEM)、能谱色散仪(EDS)及X射线衍射仪(XRD)表征其表面形貌、化学组成及晶型.结果表明,采用喷砂酸蚀,钛表面形成10~20μm喷砂凹陷及5~8μm酸蚀坑构成两级微米级结构,阳极氧化构造出10nm左右的纳米级第3级结构.体外实验显示,多级微/纳米复合结构样品相对于对照组具有更好的生物活性.通过表面多级结构的构筑及热处理,钛种植体的亲水性和生物活性均有较大幅度的提高.     

静电纺ZnO-PLLA/PLLA纳米纤维过滤膜的制备及性能研究

利用静电纺丝法制备了可用于抗菌口罩滤芯层的氧化锌-左旋聚乳酸/左旋聚乳酸(ZnO-PLLA/PLLA)复合纳米纤维膜.以纤维膜的过滤性和透气性为指标,通过正交实验分析了ZnO-PLLA/PLLA共混比例、质量分数、混合溶剂中二氯甲烷/N,N-二甲基甲酰胺(DCM/DMF)的质量比例、纺丝流速、纺丝电压及纺丝时间这6个实验因素对纳米纤维膜性能的影响,优化的制备参数为ZnO-PLLA/PLLA的质量分数为8%.其中,ZnO负载量为2%,DCM/DMF质量比为6.5∶1,纺丝电压为9 kV,流速为0.004 mm/s,时间为30 min,优化条件下制备纳米纤维粗细分布比较均匀,过滤和透气性能测试结果均达到国标医用防护口罩技术要求.     

聚乳酸/聚环氧乙烷纳米纤维膜的结构与性能表征

采用静电纺丝方法制备了聚乳酸(PLLA)/聚环氧乙烷(PEO)纳米纤维膜,利用扫描电子显微镜(SEM)、差示扫描量热(DSC)、X-射线衍射(XRD)和拉伸测试,对PLLA/PEO纳米纤维膜的形貌、结构、结晶行为和力学性能进行了表征,探究了PEO的质量分数对PLLA/PEO纳米纤维膜的结构、结晶行为和力学性能的影响。结果表明,PEO的加入,降低了PLLA/PEO纳米纤维膜的平均直径和直径分布宽度,提高了纤维的结晶速度、结晶度及断裂伸长率;PEO分子可提高聚乳酸分子链的运动能力和降低纤维的取向度,从而降低因取向引起的中间相含量,提高结晶相含量,进而改善聚乳酸纤维的结晶性能和韧性。     

微波辐射与碳基纳米材料协同实现聚乳酸结晶形态调控与高性能化

为提高左旋聚乳酸(PLLA)的结晶性能,以氧化石墨烯(GO)和碳纳米管(CNT)为功能化纳米补强剂,在微波场下辐射5 min后制备PLLA/GO-5和PLLA/CNT-5复合薄膜材料;采用偏光显微镜和扫描电子显微镜观察复合薄膜在微波辐射下的晶体形态.结果表明:微波辐射和碳基纳米材料对PLLA的结晶性能形成了显著的协同增...     

聚乳酸/无机纳米粒子复合材料研究进展

 综述了近年来国内外关于聚乳酸/无机纳米粒子复合材料的研究和发展状况。研究表明将聚乳酸与无机纳米粒子通过复合改性,能够明显提高复合材料各方面的性能,从而扩展了聚乳酸的应用范围。聚乳酸/无机纳米复合材料分为两类,一类是层状硅酸盐无机纳米复合材料,另一类是无机纳米刚性粒子,主要包括二氧化硅、二氧化钛、氧化镁、氧化锌等氧化物。介绍了两类复合材料的制备方法,包括原位聚合法、共混法和溶胶凝胶法,阐述了无机纳米粒子的添加对聚乳酸力学性能、热稳定性能、结晶性能、降解性能、流变性能和气体阻隔性能的影响。未来的发展方向是希望通过加入具有一定特性的纳米粒子,制备出特定功能的聚乳酸无机纳米粒子复合材料。     

间歇式静电纺丝制备纳米纤维药物控释系统

利用间歇式静电纺丝技术,分别以聚乳酸(PLLA)、聚己内酯(PCL)、聚乙烯吡咯烷酮(PVP)、聚丙烯腈(PAN)、聚乙二醇(PEG)等高分子材料单独或以不同配比制备纳米纤维.针对纺丝过程中容易出现的黏连现象,通过间歇式静电纺丝技术的控制,有效避免了黏连.对所得纳米纤维产品的形貌、结构、性质进行表征,初步考察所制备的纳米纤维在不同溶液中的降解行为,以选择合适的体系作为可控降解的载体担载不同的药物,构建载药复合纳米纤维.     

静电纺PLA/Ag-TiO_2纳米纤维膜的制备及性能

利用静电纺丝技术,将聚乳酸(PLA)和载银二氧化钛(Ag-TiO_2)进行混合纺丝,制备PLA/Ag-TiO_2复合纳米纤维膜。将制备的PLA/Ag-TiO_2复合纳米纤维膜应用于亚甲基蓝溶液的催化降解和空气过滤领域,研究其光催化、过滤和重复使用等性能。同时采用扫描电子显微镜(SEM)和能量色散X射线光谱仪(EDX)对纳米纤维膜进行表征。研究结果表明:当PLA/Ag-TiO_2纺丝液中PLA的质量分数为10%(Ag-TiO_2占PLA的质量分数为2%)时,制备的复合纳米纤维膜的纤维形态较好,纤维直径更加均匀;使用50mg复合纳米纤维膜光催化降解质量浓度为5mg/L的50mL亚甲基蓝溶液,反应时间达到80min时,亚甲基蓝降解率达到53.50%,纳米纤维膜重复使用5次后,依然保持良好的光催化性能;同时复合纳米纤维膜具有优异的过滤性能,其空气过滤效率最高达到95.70%。     

Hippocampal Neuron-Derived Extracellular Matrix Coated Nanofibrous Scaffold for Neural Tissue Engineering

The aim of this study is to prepare poly-L-lactide( PLLA) electrospun nanofibrous scaffolds coated with hippocampal neuron-derived extracellular matrix( N-ECM)and construct a novel neural tissue engineering scaffold.Neonatal rat hippocampal neurons were seeded on PLLA nanofibers,and then decellularized to derive a cell-free extracellular matrix loaded N-ECM/PLLA modified scaffolds. The morphology and ingredients of N-ECM/PLLA were observed by scanning electron microscopy( SEM) and immunofluorescence staining respectively, and the cytocompatibility of the composite scaffolds was characterized by cell count kit-8( CCK-8) assay. The N-ECM was clearly identified loading on scaffolds when being imaged via SEM and immunofluorescence staining results showed that the N-ECM was made up of fibronectin and laminin. Most importantly, compared with tissue culture polystyrene and pure scaffolds, N-ECM/PLLA scaffolds could effectively facilitate the proliferation of rat adrenal neuroma cells( PC12 cells),indicating their better cell compatibilities. Based on the combination of N-ECM and PLLA biomaterials,the present study has fabricated a unique and versatile neural tissue engineering scaffold,offering a new thought for future neural tissue engineering.     

Incorporation of Sphingosine 1-Phosphate Loaded Mesoporous Silica Nanoparticles into Poly( L-lactic acid ) Nanofibrous Scaffolds for Bone Tissue Engineering

Controlled release of the functional factors is the key to improve clinical therapeutic efficacy during the tissue repair and regeneration.The three-dimensional(3D)scaffold can provide not only physical properties such as high strength and porosity but also an optimal environment to enhance tissue regeneration.Sphingosine1-phosphate(S1P),an angiogenic factor,was loaded into mesoporous silica nanoparticles(MSNs)and then incorporated into poly(L-lactic acid)(PLLA)nanofibrous scaffold,which was fabricated by thermally induced phase separation(TIPS)method.The prepared scaffolds were examined by attenuated total reflection Fourier transform infrared spectroscopy(ATR-FTIR),scanning electron microscopy(SEM),and transmission electron microscopy(TEM)and compressive mechanical test.The ATR-FTIR result demonstrated the existence of MSNs in the PLLA nanofibrous scaffold.The SEM images showed that PLLA scaffold had regular pore channel,interconnected pores and nanofibrous structure.The addition of MSNs at appropriate content had no visible effect on the structure of scaffold.The compressive modulus of scaffold containing MSNs was higher than that of the scaffold without MSNs.Furthermore,fluorescein isothiocyanate(FITC)was used as model molecule to investigate the release behavior of S1P from MSNsincorporated PLLA(MSNs/PLLA)nanofibrous scaffold.The result showed that the composite scaffold largely reduced the initial burst release and exhibited prolonged release of FITC than MSNs.Thus,these results indicated that S1P-loaded composite nanofibrous scaffold has potential applications for bone tissue engineering.     

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.     

电纺聚-L-乳酸/β-磷酸三钙复合物纳米纤维膜

利用静电纺丝法制备了生物可吸收聚-L-乳酸(PLLA)/β-磷酸三钙(β-TCP)复合物纳米纤维膜.采用扫描电子显微镜(SEM)、场发射扫描电子显微镜(FESEM)等手段研究了复合物纳米纤维膜的结构和形态,详细探讨电纺工艺条件对制备PLLA/β-TCP复合物纳米纤维的形态影响.通过拉伸力学测试、噻唑蓝比色法(MTT)对复合物纳米纤维膜的力学性能和体外细胞相容性作了进一步研究.结果表明,PLLA/β-TCP复合物纳米纤维的几何结构与电纺条件有关,随着聚合物溶液浓度增加、溶液流速增大,纤维直径有不同程度的增大;复合物纳米纤维膜的拉伸强度和杨氏模量随β-TCP的含量增加而下降;复合物纳米纤维膜对L-929细胞系无细胞毒性,显示良好的细胞相容性.     

Preparation of composite tubular grafts for vascular repair via electrospinning

A novel type of composite vascular graft was developed via electrospinning in the present investigation.Collagen and chitosan were blended to form the inner and outer layer.Poly(1-lactide-co-caprolacto...     

Fabrication and characterization of electrospun poly-L-lactide/gelatin graded tubular scaffolds: Toward a new design for performance enhancement in vascular tissue engineering

In this study, a new design of graded tubular scaffolds have been developed for the performance enhancement in vascular tissue engineering. The graded poly-L-lactide (PLLA) and gelatin fibrous scaffolds produced by electrospining were then characterized. The morphology, degradability, porosity, pore size and mechanical properties of four tubular scaffolds (graded PLLA/gelatin, layered PLLA/gelatin, PLLA and gelatin scaffolds) have been investigated. The tensile tests demonstrated that the mechanical strength and also the estimated burst pressure of the graded scaffolds were significantly increased in comparison with the layered and gelatin scaffolds. This new design, resulting in an increase in the mechanical properties, suggested the widespread use of these scaffolds in vascular tissue engineering in order to prepare more strengthened vessels.     

Disc-Electrospun PCL Nanofiber Formed Micro-patterned Structure Scaffold

Disc-electrospinning using a disc as spinneret and a rotary drum as collector is a novel technology to prepare nanofiber which has been applied in tissue engineering scaffolds. In this study, nanofibrous mats with mlcro-patterned structure were fabricated via disc-electrospinning. Poly （ε-eaprolactone） （PCL） was dissolved in trifluoroethanol （TFE） at various concentrations （ 2 %-7 % ） （w/v） for electrospinning and the applied voltage ranged from 40 to 70 kV. Scanning electron microscopy （SEM） was employed to observe the morphology of the nanofibrous scaffolds. SEM images illustrated that the nanofibers with beads formed micro-patterned structure such as triangles and other polygons. The average diameter of nanofibers presented various size with the concentration increased from 2% to 7%. The beads on the nanofibers constructed the vertexes of the polygons, while nanofibers bridged between adjacent vertexes. The concentration of solution and applied voltage may be two dominant factors to influence the topological structure of the nanofibrons scaffolds. Cells cultured on the micro-patterned scaffold spread along the edges of the polygons. The scaffold with patterned structure may have a promising application in tissue engineering.     

双螺杆反应挤出制备碳纤维增强尼龙6复合材料的研究(英文)

为了实现连续规模化生产以及碳纤维在尼龙6复合材料中的均匀分布,采用了长径比为32:1的SLJ-35B型双螺杆挤出机.结果显示碳纤维在复合材料中分布非常均匀,碳纤维平均长径比约为20:1;在潮湿环境下与纯尼龙相比,碳纤维增强后的尼龙6复合材料各项性能的稳定性明显增加;扫描电镜照片显示碳纤维与尼龙基体强化学耦合显著提高了复合材料的整体粘结性.     

毛竹与樟子松木材孔隙结构的比较

【目的】竹木材料孔隙结构特征是影响材料性能的重要因素。通过定量表征与直观观察相结合方式探索竹木材料内部孔隙结构特征。通过对比分析,建立竹木材料内部孔隙结构与组织构造的对应关系,分析竹木材料内部孔隙结构差异,研究孔隙结构对材料性能的影响。【方法】以毛竹和樟子松木材为试验材料,采用压汞法对材料的孔隙率、孔体积、孔径分布、比表面积等参数进行定量测试,分析材料的孔隙结构特征。采用扫描电镜对材料的组织结构(毛竹:导管、筛管、薄壁细胞和纹孔等部位。樟子松:管胞、射线薄壁细胞、纹孔等部位)进行观察,确定各组织结构所构成孔隙的孔径范围。【结果】孔隙率(毛竹47.58%、樟子松67.16%)及汞压入量(毛竹0.633 mL/g、樟子松1.596 mL/g)测试结果表明毛竹内部孔体积显著低于樟子松。总孔面积(毛竹82.04 m²/g、樟子松18.16 m²/g)及中孔孔径(毛竹33.8 nm、樟子松445.0 nm)对比结果表明毛竹中大部分孔隙集中在孔径较小区域(32.4 nm左右),而樟子松木材中孔隙孔径主要集中在226.7、7 082.3 nm左右,造成毛竹孔面积显著高于樟子松木材。结合扫描电镜观察结果可知,毛竹中孔径11.3～100 μm范围内孔隙主要对应导管、基本组织中的薄壁细胞及纤维细胞。而835.0 nm左右孔隙对应基本组织及纤维细胞上纹孔。樟子松木材中孔径20 μm左右孔隙对应樟子松木材管胞; 而7 082.3 nm左右孔隙则对应具缘纹孔的纹孔口和射线薄壁细胞。此外,毛竹和樟子松木材中孔径小于1 μm的孔隙结构(毛竹中32.4 nm左右,樟子松木材中226.7、749.9 nm左右)主要位于具缘纹孔塞缘及细胞壁上。【结论】采用压汞法和扫描电镜观察方法可以实现对毛竹及樟子松木材孔隙结构的表征分析,有助于分析竹木材料性能差异产生的原因。然而,在通过压汞测试材料孔隙结构参数时,受墨水瓶孔效应影响,部分孔径较大的孔隙被认为是小孔,影响测试结果的准确性。因此,后续研究应考虑竹木材料的孔隙形态,从而实现对竹木材料孔隙结构的全面准确表征。