基于可控定向PVDF电纺纤维构建细胞相容性的三维微环境（英文）

三维电纺纤维在生物医学领域,如生物传感、药物控制释放与组织工程等方面具有良好的应用前景.然而,现有的电纺技术在制备结构、孔隙率与形貌均可调节的三维定向电纺纤维方面还存在一定不足.因此亟需开发一种新型的电纺丝工艺以制备三维定向电纺纤维.本文通过改进传统的电纺丝工艺,开发了一种简单高效制备三维定向聚偏氟乙烯(PVDF)的电纺丝制备技术.所制备的三维定向纤维的形貌、直径及纤维密度均可控.体外细胞实验结果表明,该类三维定向纤维具有良好的生物相容性,能够促进细胞活性,诱导细胞沿着纤维的方向生长.此外,研究结果还表明,将该三维定向纤维作为细胞培养支架时,细胞的增殖高于利用传统的二维纤维膜.该制备技术将极大地拓宽三维定向纤维在三维细胞培养、组织工程及疾病诊断等生物医学领域的应用.     

生物可降解电活性苯胺聚合物

导电聚合物通过其独特的电活性或导电性,可智能地传递或控制细胞电化学信号,从而定向诱导组织器官的再生修复,已成为神经和组织工程领域研究的热点.本文主要介绍了我们实验室生物可降解电活性苯胺聚合物的相关工作,介绍了以苯胺齐聚物与可降解高分子接枝或嵌段制备具有电活性、可生物降解的新型导电聚合物及其在细胞培养和组织工程方面的研究.介绍了静电纺丝制备电活性纳米纤维的概况.苯胺齐聚物与可降解聚合物的接枝和嵌段可同时赋予其电活性、生物相容性和生物可降解性.可生物降解的电活性聚合物是未来生物组织工程领域的发展趋势之一,具有广阔的应用前景.     

生物高分子静电纺丝研究进展

静电纺丝(电纺)技术是一种制备直径为数十纳米到数微米的纳米纤维的有效方法。由于生物高分子具有良好的生物相容性,近年来国内外对生物高分子的电纺制备进行了大量研究。这种生物高分子纳米纤维在组织工程支架、组织修复等方面有独特的优势。本文对生物高分子——多糖、蛋白质、核酸(DNA)的静电纺丝研究进行了总结。     

含骨脱细胞基质电纺纤维的成骨性能

通过脱细胞技术制备了猪骨脱细胞基质(DBM), 用胃蛋白酶消化DBM使其变为可溶形式, 采用静电纺丝技术制备了含有DBM的左旋聚乳酸(PLLA)电纺纤维(PLLA/DBM), 并对PLLA/DBM的形貌、 亲水性、 细胞相容性、 成骨性能和体外矿化能力进行评价. 研究结果表明, 脱细胞处理能够有效去除骨组织中的细胞成分, 使DNA含量显著下降. DBM经胃蛋白酶处理后溶于六氟异丙醇(HFIP), 可进行静电纺丝, 制备的PLLA/DBM[m(PLLA)∶m(DBM)=10∶0, 9∶1, 7∶3, 5∶5]电纺纤维具有良好的亲水性, 且无细胞毒性, 对骨髓间充质干细胞的黏附及成骨分化有明显的诱导促进作用, 体外生物矿化效果优良.     

生物可降解及生物材料的电场纺丝及应用

电场纺丝是制备生物可降解及生物材料纳米纤维非织造布的简单工艺,由于纳米纤维具有较大的比表面积,具有多孔结构,使其在生物医学领域,如：组织工程、药物缓释及医用纱布等领域有潜在的应用前景。本文综述了生物降解材料及生物材料的电场纺丝及其应用。     

离子浓度对电纺纤维沉积形态及表面形貌的影响

通过采用传统电纺丝装置(接收板接地或连接负压电源)、逆向电场及非接触式电纺丝装置等4种不同的电纺丝装置,在相同电压、接收距离、纺针直径、温湿度条件下,对20%的聚乙烯醇溶液进行电纺丝实验,观察不同装置中制得的纤维的沉积形态与形貌.还采用ANSYS有限元模拟对电纺丝装置的场强分布进行分析,并引入电化学理论解释了采用不同电纺装置时离子浓度的不同对所得电纺纤维形貌的影响,分析了产生差异的原因.     

静电纺丝法制备多壁碳纳米管/聚乙烯醇复合纤维的综合实验设计

设计了静电纺丝法制备多壁碳纳米管/聚乙烯醇复合纤维综合实验。该实验对纺丝浓度、纺丝电压、接收距离、接收面积、多壁碳纳米管的改性及其添加量对复合纤维形貌的影响进行研究,对纤维进行了红外光谱、扫描电镜测试分析,得到优化的静电纺丝制备多壁碳纳米管/聚乙烯醇复合纤维的电纺工艺。该实验易于分组操作,涉及高分子材料的改性、制备、形貌表征和结果分析等多方面内容,有利于学生巩固理论知识,提高实践能力和综合应用能力。     

天然产物静电纺纳米纤维在生物医药方面的应用

静电纺丝制备的纳米纤维由于其网状结构具有较大的比表面积和较高的孔隙率,而在能源环境、医疗保健、食品包装、纳米设备开发等多个领域中成为研究热点,尤其是在包括药物运输、伤口护理以及组织工程等在内的生物医学领域中受到了广泛的关注。本文针对天然产物在电纺纳米纤维中的相关研究和发展进行了全面的综述,讨论了他们在生物医药方面的应用以及制备方法,并对其未来前景作出了展望。     

稳定射流电纺丝法制备定向排列的壳聚糖超细纤维

采用电驱动纺丝,以壳聚糖(CTS)为研究对象材料,通过引入超高分子量聚氧化乙烯(PEO)调节纺丝液的黏弹性,实现抑制电纺丝固有的射流不稳定弯曲摆动来得到单一的稳定射流,从而可以像传统工业上的干、湿法纺丝一样制备定向的超细CTS纤维(称为稳定射流电纺丝,SJES).系统地研究了SJES的工艺参数(如CTS/PEO质量比、纺丝电压、接收距离、凝固浴成分、辊筒转速等)对制备定向的超细壳聚糖纤维的影响,并通过SEM、FTIR、WAXD、纳米力学拉伸仪等研究了所制备纤维的形貌、结构与性能.结果表明,SJES法制备的CTS纤维直径在10μm以下,优化参数(如电压和辊筒转速)可使纤维直径细化到3μm左右.纤维单丝具有较高的力学性能,断裂强度和纤维模量可以分别达到(762±93)MPa和(11±6)GPa.稳定射流电纺丝方法制备的超细纤维与常规电纺丝法制备的纤维相比,具有较高的微晶取向度.     

溶剂性质对两亲性聚肽静电纺丝的影响

通过对聚(γ-苄基L-谷氨酸酯)(PBLG)的亲水改性制备了两亲性聚(γ-苄基L-谷氨酸酯-co-羟乙谷酰胺)无规共聚肽(PBHG)用于静电纺丝制备超细纤维.通过傅里叶变换红外光谱、核磁共振氢谱表征了聚合物结构.通过测定溶液表面张力、黏度、电导率及扫描电镜观察纤维形貌考察了不同溶剂及PBHG浓度对纺丝溶液性质及电纺纤维的影响.通过水浸实验及MTT法评价了电纺纤维膜的亲水性及细胞相容性.研究发现在三氯甲烷(TCM)和四氢呋喃(THF)中PBHG采取α-螺旋构象,刚性分子链自取向排列,可获得直径为微米或亚微米的电纺纤维.以TCM为溶剂时,因溶液表面张力大、导电率低导致纤维品质较差,而以THF为溶剂可获得表面光洁、尺寸均匀的电纺纤维.当溶剂为三氟乙酸(TFA)时,PBHG采取无规线团构象,柔性分子链彼此缠结,同时溶液表面张力小、黏度低、电导率高,可获得纳米电纺纤维.但因TFA挥发性相对较差,易造成纤维粘连.将TFA与TCM复配后作为溶剂可改善纤维粘连问题.与PBLG电纺纤维相比,改性后的PBHG电纺纤维的亲水性得到了改善,可在水中保持纤维骨架而无需交联,并表现出良好的细胞相容性,能促进细胞在电纺纤维膜上的增殖.     

Improved cellular response on multiwalled carbon nanotube-incorporated electrospun polyvinyl alcohol/chitosan nanofibrous scaffolds

We report the fabrication of multiwalled carbon nanotube (MWCNT)-incorporated electrospun polyvinyl alcohol (PVA)/chitosan (CS) nanofibers with improved cellular response for potential tissue engineering applications. In this study, smooth and uniform PVA/CS and PVA/CS/MWCNTs nanofibers with water stability were formed by electrospinning, followed by crosslinking with glutaraldehyde vapor. The morphology, structure, and mechanical properties of the formed electrospun fibrous mats were characterized using scanning electron microscopy, Fourier transform infrared spectroscopy, and mechanical testing, respectively. We showed that the incorporation of MWCNTs did not appreciably affect the morphology of the PVA/CS nanofibers; importantly the protein adsorption ability of the nanofibers was significantly improved. In vitro cell culture of mouse fibroblasts (L929) seeded onto the electrospun scaffolds showed that the incorporation of MWCNTs into the PVA/CS nanofibers significantly promoted cell proliferation. Results from this study hence suggest that MWCNT-incorporated PVA/CS nanofibrous scaffolds with small diameters (around 160 nm) and high porosity can mimic the natural extracellular matrix well, and potentially provide many possibilities for applications in the fields of tissue engineering and regenerative medicine.     

Fabrication of fibrous patterned architectures with controlled deposition and multidirectional alignment

In recent years, the ability to produce nanofibrous patterned architectures by electrospinning has exposed a wide range of potential applications in biomedical and industrial fields. Directional alignment, controlled deposition, and density variation into the patterns are desirable for many applications such as tissue engineering scaffolds and micro/nano‐electronic devices. In this study, we introduce a versatile method for fabrication of various kinds of nanofibrous deposition patterns with the help of microprocessor based control system for switching collector electrodes. By controlling the concurrent activation time of two adjacent electrodes, we demonstrated that amount of fibers going into the pattern can be adjusted and alignment in electrospun fibers can be obtained. We also revealed that the deposition density of electrospun fibers in different areas of patterned architectures can be varied. This advanced technique can have a significant impact in enhancing the technology of electrospinning and can help develop new applications in health sciences and industrial sectors. Copyright © 2015 John Wiley & Sons, Ltd.     

Dual-syringe reactive electrospinning of cross-linked hyaluronic acid hydrogel nanofibers for tissue engineering applications

A facile fabrication of a cross-linked hyaluronic acid (HA) hydrogel nanofibers by a reactive electrospinning method is described. A thiolated HA derivative, 3,3'-dithiobis(propanoic dihydrazide)-modified HA (HA-DTPH), and poly(ethylene glycol) diacrylate (PEGDA) are selected as the cross-linking system. The cross-linking reaction occurs simultaneously during the electrospinning process using a dual-syringe mixing technique. Poly(ethylene oxide) (PEO) is added into the spinning solution as a viscosity modifier to facilitate the fiber formation and is selectively removed with water after the electrospinning process. The nanofibrous structure of the electrospun HA scaffold is well preserved after hydration with an average fiber diameter of 110 nm. A cell morphology study on fibronectin (FN)-adsorbed HA nanofibrous scaffolds shows that the NIH 3T3 fibroblasts migrate into the scaffold through the nanofibrous network, and demonstrate an elaborate three-dimensional dendritic morphology within the scaffold, which reflects the dimensions of the electrospun HA nanofibers. These results suggest the application of electrospun HA nanofibrous scaffolds as a potential material for wound healing and tissue regeneration. [image: see text] Laser scanning confocal microscopy demonstrates that the NIH3T3 fibroblast develops an extended 3D dendritic morphology within the fibronectin-adsorbed electrospun HA nanofibrous scaffold.     

Electrospun poly(aniline‐co‐ethyl 3‐aminobenzoate)/poly(lactic acid) nanofibers and their potential in biomedical applications

Poly(aniline‐co‐ethyl 3‐aminobenzoate) (3EABPANI) copolymer was blended with poly(lactic acid) (PLA) and co‐electrospun into nanofibers to investigate its potential in biomedical applications. The relationship between electrospinning parameters and fiber diameter has been investigated. The mechanical and electrical properties of electrospun 3EABPANI‐PLA nanofibers were also evaluated. To assess cell morphology and biocompatibility, nanofibrous mats of pure PLA and 3EABPANI‐PLA were deposited on glass substrates and the proliferation of COS‐1 fibroblast cells on the nanofibrous polymer surfaces determined. The nanofibrous 3EABPANI‐PLA blends were easily fabricated by electrospinning and gave enhanced mammalian cell growth, antioxidant and antimicrobial capabilities, and electrical conductivity. These results suggest that 3EABPANI‐PLA nanofibrous blends might provide a novel bioactive conductive material for biomedical applications. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.     

Enhanced orientation of PEO polymer chains induced by nanoclays in electrospun PEO/clay composite nanofibers

Polymer fibers composed of poly(ethylene oxide) (PEO) and nanoclay were fabricated by electrospinning. The morphology of the composite nanofibers was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM), which showed aligned nanoclays in the fibers. Polarized Fourier transform infrared (FT-IR) spectroscopy revealed that the PEO chains in the composite fibers exhibit a higher degree of orientation than that in PEO nanofibers containing no nanoclay. It is believed that spatial confinement is present in the electrospun nanofibers, which results in the enforcement of the mutual restriction. The anisotropic hierarchical nanostructure may have potential applications in optics, mechanical materials, and biomedical materials for cell culture.     

Solvent Influences the Morphology and Mechanical Properties of Electrospun Poly(L-lactic acid) Scaffold for Tissue Engineering Applications

Electrospun micro- and nanofiber scaffolds have gained interest in biomedical applications, especially in tissue engineering, because they can be used to reproduce the structure of the extracellular matrix (ECM) of natural tissue. The selection of the solvent is an important factor which affects the diameter, the surface morphology and the crystallinity of the electrospun fibers, and, accordingly, their mechanical properties as well as their degradation kinetics. Furthermore, the surface morphology of the electrospun fibres can be controlled by solvent vapour pressure to produce porous structures which might be helpful for cell adhesion and proliferation. In the present work, poly (L-lactic acid) (PLLA) has been electrospun using solvents with different vapour pressures to investigate the influences of the solvent vapour pressure on morphology, diameter, crystallinity and mechanical properties of the electrospun fiber scaffolds. The results show that the vapour pressure of the solvents (or solvent mixtures) play an important role in the fiber diameter and crystallinity. Furthermore, the crystallinity of the fibers is increased by lowering the vapour pressure of the used solvent. In addition, the mechanical properties (e.g., tensile strength and Young's modulus) are strongly dependent on morphological features such average fibers diameter. The smaller the average diameter, the higher the tensile strength and Young's modulus.     

Advances in the scaffolds fabrication techniques using biocompatible polymers and their biomedical application: A technical and statistical review

With the advancement in tissue engineering, researchers are working hard on new techniques to fabricate more advanced scaffolds from biocompatible polymers with enhanced porosity, appropriate mechanical strength, diverse shapes and sizes for potential applications in biomedical field in general and tissue engineering in particular. These techniques include electrospinning, solution blow spinning, centrifugal spinning, particulate leaching (salt leaching), freeze-drying, lithography, self-assembly, phase separation, gas foaming, melt molding, 3-D printing, fiber mesh and solvent casting. In this article we have summarized the scaffold’s fabrication techniques from biocompatible polymers that are reported so far, the recent advances in these techniques, characterization of the physicochemical properties of scaffolds and their potential applications in the biomedical field and tissue engineering. The article will help both newcomers and experts working in the biomedical implant fabrication to not only find their desired information in one document but also understand the fabrication techniques and the parameters that control the success of biocompatible polymeric scaffolds. Furthermore, a static analysis of the work published in all forms on the most innovative techniques is also presented. The data is taken from Scopus, restricting the search to biomedical fields and tissue engineering.     

Tuning size scale and crystallinity of PCL electrospun fibres via solvent permittivity to address hMSC response

The effect of solvent permittivity on the fibre morphology of PCL electrospun membranes for tissue engineering applications is studied. Morphological results indicate that polar solvents with higher permittivity are able to promote the formation of sub-micrometric fibres, while apolar solvents yield microfibres with an average fibre diameter of 2.86 ± 0.31 μm. Polymer/solvent interactions and electrospinning process parameters influence the mechanism of fibre and bead formation. It is shown that the dielectric properties of solvents influence the fibre size scale and crystallinity and directly contribute to the biological response of stem cells. Solvent permittivity is a key factor in controlling the morphological and physical properties of electrospun fibre meshes.     

Fabrication and characterization of polycrystalline WO3 nanofibers and their application for ammonia sensing

We describe the fabrication and characterization of tungsten oxide nanofibers using the electrospinning technique and sol-gel chemistry. Tungsten isopropoxide sol-gel precursor was incorporated into poly(vinyl acetate)(PVAc)/DMF solutions and electrospun to form composite nanofibers. The as-spun composite nanofibers were subsequently calcinated to obtain pure tungsten oxide nanofibers with controllable diameters of around 100 nm. SEM and TEM were utilized to investigate the structure and morphology of tungsten oxide nanofibers before and after calcination. The relationship between solution concentration and ceramic nanofiber morphology has been studied. A synchrotron-based in situ XRD method was employed to study the dynamic structure evolution of the tungsten oxide nanofibers during the calcination process. It has been shown that the as-prepared tungsten oxide ceramic nanofibers have a quick response to ammonia with various concentrations, suggesting potential applications of the electrospun tungsten oxide nanofibers as a sensor material for gas detection.     

Electrospinning of ultrafine core/shell fibers for biomedical applications

Because of the inherent appearance similar to the natural extracellular matrix, ultrafine fibrous membranes prepared via electrospinning exhibit widespread applications, especially in the biomedical area. Extensional modifications of coaxial and emulsion electrospinning have drawn much attention in preparation of core/shell fibers for applications as tissue engineering scaffolds and controlled delivery systems for bioactive substances. Due to incorporation of multi-components in the electrospun core/shell fibers, the process of coaxial and emulsion electrospinning became more susceptible. The theories have not been fully understood. A series of investigations were carried out evaluating the systematic and processing parameters. This paper reviews advantages and potentials of electrospun core/shell fibers as well as factors influencing their formation on the basis of our research and new progress.