聚乳酸/胶原蛋白取向纳米纤维支架的性能

为研究取向纳米纤维的性能及取向纳米纤维对细胞生长的引导作用,利用可降解的聚乳酸和胶原蛋白为原料,通过静电纺丝方法制备了随机和取向排列的聚乳酸（PLLA）、聚乳酸 ∕ 胶原蛋白（PLLA ∕Coll）纳米纤维支架材料。利用扫描电镜、红外光谱仪等研究了纳米纤维的形态结构、化学性能和力学性能等,并在其表面培养间充质干细胞（MSCs）,研究细胞在不同的支架表面的生长形态。结果表明：取向纳米纤维具有较细的纤维直径,各向异性的结构性能,平行于纤维排列方向的润湿性能和优于垂直于纤维排列方向的断裂强度。复合 PLLA ∕ Coll 支架表面含有细胞识别基团,能增强细胞的黏附和增殖,培养在取向 PLLA ∕ Coll 纳米纤维支架上的 MSCs 呈现取向的纺锥形态,与体内 MSCs 的形态更类似。     

聚乳酸/聚乙醇酸新型纳米支架载药体系研制

以具有良好生物降解性、相容性和降解产物无毒性的聚乳酸/聚乙醇酸(PLGA)为原料,通过静电纺丝制备PLGA载盐酸四环素(Tet)纳米纤维膜,制备组织工程支架材料。通过扫描电镜(SEM)和荧光显微镜观察纳米纤维膜的形貌结构及细胞与膜的黏附、生长情况;用紫外光分光光度计检测药物的吸光度,并计算其释药速率;通过改良的Kirby-Bauer方法观察其体外抑菌性能。结果显示:不同载药量纳米纤维膜的平均直径在360~470 nm之间,无显著差异;载药量为10%的纳米纤维突释最大,在体外可持续释药27 d以上。体外抗菌活性结果表明纳米纤维膜对金黄色葡萄球菌均有瞬时、长效的抑菌活性。SEM结果显示人成骨样细胞MG-63与纳米纤维膜在支架上共培养后生长良好,表明其细胞相容性好。     

胶原蛋白改性聚乳酸-羟基乙酸载药纳米纤维膜的制备及其性能

为改善聚乳酸-羟基乙酸共聚物(PLGA)基药物载体的降解性能和释药性能,以PLGA为基材,以胶原蛋白(Col)为改性材料,以阿霉素(DOX)为药物模型,利用静电纺丝技术制备得到PLGA/Col/DOX纳米纤维膜,探究了胶原蛋白对其亲疏水性、体外降解性、释药性能及细胞相容性的影响。结果表明：PLGA与Col以3：1的质量比复合制得的纳米纤维膜性能最佳;经胶原蛋白复合改性后,纳米纤维膜的接触角由未改性的93.5°降至51.5°,亲水性显著提高;胶原蛋白改性可大幅提高PLGA的降解性,改性后纳米纤维膜30 d的质量损失速率由未改性的3.5%增加至19%,且改性后纳米载药纤维膜的药物释放速率和细胞相容性明显提高,有利于细胞黏附增殖。     

聚己内酯/聚乙二醇大孔径纳米纤维膜的制备及其在组织工程支架中的应用

为使细胞在静电纺纳米纤维支架上得到更佳的生长与黏附,采用改进的静电纺丝装置制备具有良好生物相容性的聚己内酯(PLC)/聚乙二醇(PEG)大孔径复合纳米纤维膜,探究纺丝溶液中溶质质量配比与溶液质量分数对纳米纤维膜形貌及性能的影响,确定最佳工艺参数;将最佳工艺条件下制备的纳米纤维膜初步应用于组织工程,并与传统静电纺丝装置制备的纤维膜进行细胞相容性对比分析。结果表明:当PLC和PEG的混纺质量比为80∶20,纺丝溶液质量分数为25%时,获得的PCL/PEG大孔径纳米纤维膜质量最好;与传统静电纺PCL/PEG纳米纤维膜相比,PCL/PEG大孔径纳米纤维膜更利于细胞的生长和增殖,更适合作为组织工程支架材料。     

细胞在丝素蛋白纳米纤维非织造布上粘附和增殖的研究

通过制备丝素蛋白水溶液,采用静电纺丝方法制备纳米纤维非织造布,并以此作为生物工程支架,研究了内皮细胞在材料表面的粘附和增殖情况。结果表明,细胞在丝素蛋白纳米纤维非织造布表面的粘附情况稳定,而且具有良好的增殖活性,材料生物相容性好,在生物医学领域具有很大的应用潜力。     

带有纳米沟槽的静电纺微米纤维支架对促进细胞渗透生长的研究

通过静电纺丝技术一步制备出表面带有纳米沟槽结构的微米级左旋聚乳酸(PLLA)纤维支架,同时具备纳米和微米结构优势.对支架的形态、力学性能、生物相容性和细胞渗透情况进行表征.结果 表明:当PLLA纺丝液浓度提高时,纤维直径随之增大,但不会影响纤维表面的纳米沟槽结构;表面的纳米沟槽结构能增大支架的比表面积,促进细胞的黏附和...     

能承受生理环境的复合管状支架的研究

大量具有理想性能的血管支架已被制备并用于临床。然而,当在高压、流动的生理环境下,许多支架的性能不能长久维持,它们最终会因快速降解、不能抵抗切变应力等原因而失效,因此就迫切需要研制一种可以适应这些条件直到血管组织在体内成熟的耐用支架。本研究通过静电纺丝法构建PCL(聚己酸内酯)/胶原蛋白复合管状支架,测定其形貌结构、生物力学性能及生物性能。该PCL/胶原蛋白复合支架由直径约520nm的纤维组成,拥有较好的断裂强度(4.0±0.4)MPa和足够的弹性(2.7±1.2)MPa,其爆破压强达(4912±155)mmHg,已远高于单一PCL血管支架和人体血管;在复合管状支架内层种植小牛血管内皮细胞(bECs),在外层种植小牛平滑肌细胞(bSMCs),结果显示在复合血管支架的外层和内层分别形成连成片的细胞层。实验表明复合血管支架具有良好的生物相容性和长期抵抗高压流的生物力学性能,并可为细胞提供良好的生长环境。     

PLA/PCL-PANI复合纳米纤维膜的制备及性能研究

利用静电纺丝技术,制备了聚苯胺掺杂的聚乳酸/聚己内酯复合导电纳米纤维膜,通过扫描电镜(SEM),探讨了不同质量分数配比下的聚苯胺对纤维膜相关性能和纤维表面形貌的影响,并采用红外光谱分析(FTIR)、X射线衍射(XRD)和热重分析法(DSC)等测试手段对纤维膜的形貌和结构进行了分析。结果表明,具有一定形貌和电导性的PANI复合纳米纤维支架,对细胞在纤维上的吸附和增殖有一定的促进作用,具有良好的生物相容性,作为生物支架材料在组织工程上具有一定的应用前景。     

能承受生理环境的复合管技术架的研究

大量具有理想性能的血管支架已被制备并用于临床。然而，当在高压、流动的生理环境下，许多支架的性能不能长久维持，它们最终会因快速降解、不能抵抗切变应力等原因而失效，因此就迫切需要研制一种可以适应这些条件直到血管组织在体内成熟的耐用支架。本研究通过静电纺丝法构建PCL（聚己酸内酯）／胶原蛋白复合管状支架，测定其形貌结构、生物力学性能及生物性能。该PCL／胶原蛋白复合支架由直径约520nm的纤维组成，拥有较好的断裂强度（4．0±0．4）MPa和足够的弹性（2．7±1．2）MPa，其爆破压强达（4912±155）mmHg，已远高于单一PCL血管支架和人体血管；在复合管状支架内层种植小牛血管内皮细胞（bECs），在外层种植小牛平滑肌细胞（bSMCs），结果显示在复合血管支架的外层和内层分别形成连成片的细胞层。实验表明复合血管支架具有良好的生物相容性和长期抵抗高压流的生物力学性能，并可为细胞提供良好的生长环境。     

空气过滤用聚氨酯纳米纤维膜的制备及其性能

为拓展静电纺纳米纤维在空气过滤领域中的应用,以聚氨酯(PU)为原料,加入不同种类的盐,采用静电纺丝法制备树枝状PU纳米纤维膜。利用扫描电镜(SEM)、接触角测试仪、红外光谱仪、自动滤料测试仪测试纳米纤维膜的微观结构、亲疏水性、化学结构和过滤性能。结果表明：在PU质量分数14%条件下,添加有机盐TBAC,纺丝电压35 kV时,制备的纳米纤维膜的树枝状分叉结构明显;TBAC的加入使纤维膜的接触角由99.1°减小到82.8°;分叉结构使纳米纤维膜的过滤性能显著提高,与纯PU纳米纤维膜相比,过滤效率从50.8%提高到93.6%,品质因子从0.009提高到0.073,可满足高效低阻空气过滤材料的需求。     

胶原纤维/聚氨酯湿法凝固复合膜的微观结构与性能研究

采用铬鞣胶原纤维粉和聚氨酯(PU),通过湿法凝固的方法制备了胶原纤维/PU复合膜,测定了胶原纤维/PU复合膜的透水汽性、透气性和力学性能。利用SEM研究了胶原纤维/PU复合膜的微孔形态。利用DSC和TGA研究了胶原纤维/PU复合膜在程序控制温度下的热效应。研究结果表明胶原纤维/PU复合膜具有分布比较均匀并相互贯通的指形微孔,这种微孔结构能够提高膜的透水汽性和透气性,同时也会降低膜的物理机械性能。DSC和TGA分析胶原纤维和PU湿法凝固复合属于物理性复合。     

Electrospun conducting polymer nanofibers and electrical stimulation of nerve stem cells

Tissue engineering of nerve grafts requires synergistic combination of scaffolds and techniques to promote and direct neurite outgrowth across the lesion for effective nerve regeneration. In this study, we fabricated a composite polymeric scaffold which is conductive in nature by electrospinning and further performed electrical stimulation of nerve stem cells seeded on the electrospun nanofibers. Poly-L-lactide (PLLA) was blended with polyaniline (PANi) at a ratio of 85:15 and electrospun to obtain PLLA/PANi nanofibers with fiber diameters of 195 ± 30 nm. The morphology, chemical and mechanical properties of the electrospun PLLA and PLLA/PANi scaffolds were carried out by scanning electron microscopy (SEM), X-ray photo electron spectroscopy (XPS) and tensile instrument. The electrospun PLLA/PANi fibers showed a conductance of 3 × 10?? S by two-point probe measurement. In vitro electrical stimulation of the nerve stem cells cultured on PLLA/PANi scaffolds applied with an electric field of 100 mV/mm for a period of 60 min resulted in extended neurite outgrowth compared to the cells grown on non-stimulated scaffolds. Our studies further strengthen the implication of electrical stimulation of nerve stem cells on conducting polymeric scaffolds towards neurite elongation that could be effective for nerve tissue regeneration.     

Oriented cartilage extracellular matrix-derived scaffold for cartilage tissue engineering

The structure of a cartilage scaffold is required to mimic native articular cartilage, which has an oriented structure associated with its mechanical function. In this study, an oriented cartilage extracellular matrix (ECM)-derived scaffold was fabricated composed of microtubules arranged in parallel in vertical section. The mechanical property was higher than that of a typical non-oriented scaffold (p<0.05). Oriented and non-oriented scaffolds were seeded with chondrogenic-induced bone mesenchymal stem cells and cell-scaffold constructs were implanted subcutaneously in the dorsa of nude mice. At 4 weeks, all samples stained positive for safranin O, toluidine blue, and collagen type II, but negative for collagen type I. Oriented-structure constructs contained numerous parallel giant bundles of densely packed collagen fibers with chondrocyte-like cells aligned along the fibers. Total DNA, glycosaminoglycans and collagen contents increased with time and these values were similar in the two groups. Compared with the native articular cartilage, the Young's modulus of the tissue-engineered (TE) cartilage reached 42.9%, 23.0% in oriented and non-oriented scaffolds respectively, at 4 weeks. These results indicate that oriented ECM-derived scaffolds enhance the biomechanical property of TE cartilage and thus represent a promising approach to cartilage tissue engineering.     

Growth factor/heparin-immobilized collagen gel system enhances viability of transplanted hepatocytes and induces angiogenesis

Hepatocyte transplantation is being explored as a treatment strategy for end-stage liver disease; however, the main limitation is the insufficient vascularization of transplanted hepatocytes. To overcome this problem, a suitable 3D microenvironment and the types of transplanted cells must be considered for hepatocyte transplantation. In this study, a growth factor (GF)/heparin-immobilized collagen gel-filled polyurethane foam (PUF) scaffold was developed for angiogenesis induction and hepatocyte transplantation. First, a vascular endothelial growth factor (VEGF)/heparin-immobilized, collagen-gel-filled PUF scaffold was developed to establish a prevascularized cavity in the subcutaneous space in rats. Second, accompanied by 70% partial hepatectomy (PH), hepatocytes were embedded inside heparin-immobilized, collagen-gel-filled PUF scaffolds, and were transplanted into the VEGF-induced prevascularized cavity. The benefits of using this system were confirmed by using three types of hepatocytes, namely single hepatocyte, hepatocyte spheroids, and fetal hepatocytes. The normalized hemoglobin content and live nucleus numbers were determined separately to evaluate the angiogenesis and viability of transplanted hepatocytes. In summary, after PH pretreatment, transplantation of fetal hepatocyte-embedded, heparin-immobilized, collagen-gel-filled PUF scaffold into a VEGF-induced prevascularized cavity appears to be a promising strategy for future liver tissue engineering.     

Electrospinning of single and multilayered scaffolds for tissue engineering applications

Optimized electrospinning conditions were applied to produce single and multilayered (ML) scaffolds composed of polycaprolactone, collagen and elastin. The ML scaffold was cross-linked with glutaraldehyde to increase the stability. Morphological and structural characteristics of the scaffolds were measured by SEM and FTIR analyses. Results revealed that polymers combined to each other well and uniform fibers were obtained with the diameters ranging from 156 ± 53 to 1536 ± 293 nm. Contact angle measurements were performed to investigate the hydrophilic character of each structure. It was observed that incorporation of the natural polymers into the blends increased the hydrophilicity. Mechanical tests proved that collagen contributed to fabricate stiffer structures while elastin provided more elasticity. Biocompatibility of the scaffolds was examined by SEM analysis and WST-1 test with mouse fibroblast cells (L929) in vitro. Results exhibited that the addition of natural polymers increased the cell growth, and none of the single and ML scaffolds presented cytotoxic effect.     

静电纺PLA/丝素-明胶管状支架的结构与性能

为研制组织工程小口径血管,以良好生物相容性和生物可降解性的聚乳酸(PLA)、丝素蛋白、明胶为原料,通过静电纺丝法,以高速旋转的滚轴为收集装置,构建了外层为PLA纤维和内层为丝素-明胶纤维的PLA/丝素-明胶复合管状支架(直径为4.5mm)。采用扫描电镜观察该管状支架的形貌结构;测定其孔隙率及生物力学性能,并在该支架上进行人脐静脉内皮细胞(HUVECs)培养实验。结果表明：PLA/丝素-明胶复合管状支架具有较高的断裂强度和较好的柔软性,爆破强度远高于人体的正常血压;支架具有多孔结构, SEM照片显示HUVECs在支架上分化、增殖、生长状态良好。     

Electrospinning of PCL/CEFUROXIM® fibrous scaffolds on 3D printed collectors

Abstract

In this paper, the effect of different collector geometry on the PCL scaffold architecture and cell viability was investigated. PCL scaffolds with antibiotic Cefuroxim^®, 15%wt. and 20%wt., were electrospun and characterized by ATR-FTIR, while thermal stability were observed by DSC and TG. PCL/15%CFU^® scaffolds were electrospun on six 3D printed collectors, three ribbed and three mesh geometries, to produce the most favourable structure for cells adhesion and proliferation. SEM study and MTT assay revealed that collectors with the widest slot in both ribbed and mesh geometries exhibited the most favourable structure to enhance cells adhesion. In general, cells spreading on the surface and cells viability proved to be better for the ribbed collectors. The study showed that by controlling the collector geometry and the scaffold three-dimensional structure, it is possible to control cell attachment and differentiation and, consequently, to adjust them for the special tissue demands in the regeneration process.     

聚乳酸-聚己内酯/丝素蛋白三元复合纳米纤维膜支架的结构与性能

通过静电纺丝技术制备出不同质量比的聚乳酸聚己内酯/ 丝素蛋白（PLA-PCL/SF）复合纳米纤维膜支架,采用扫描电子显微镜、傅里叶红外光谱仪对纳米纤维膜的形貌和结构进行表征,测试纤维膜的孔隙率和吸附性能。结果表明：PLA-PCL与SF 这2 种组分的质量比对复合纳米纤维膜的形貌有显著影响,质量比为90:10和70:30的纳米纤维表面分布着密集的孔洞;PLA-PCL/SF复合纳米纤维膜中SF 经甲醇处理后由无定形结构转变为β?折叠结构;随着复合纳米纤维膜中SF 含量的增加,纳米纤维膜的孔隙率和吸附性也逐渐降低。接触角实验和小鼠胚胎成纤维细胞（NIH-3T3）培养结果表明,SF的加入提高了纳米纤维膜的亲水性,有利于NIH-3T3细胞的黏附和增殖。