共查询到19条相似文献,搜索用时 171 毫秒
1.
目前聚合物熔体电纺技术制备的纤维大多以杂乱无序的无纺布形式存在,限制了电纺技术在组织工程支架以及机器人等需要有序结构领域的应用。本文将熔体电纺技术与三维运动平台相结合,采用自主设计的熔体电纺可控成型实验装置,对聚己内酯(PCL)进行熔体直写静电纺丝,获得了有序纤维。研究了喷头移动速度、接收距离和纺丝电压对熔体直写电纺纤维沉积形貌的影响。结果表明,纤维直径随着喷头移速、接收距离和纺丝电压的增大而减小,其中接收距离的改变对直径的影响最为显著;接收距离的增大虽然有利于纤维的细化,但是距离过大会使纤维沉积的有序性变差;当射流下落速度与喷头移动速度相匹配时,射流才能实现有序沉积;增大接收距离和纺丝电压会引起射流鞭动,需要相应地增大喷头移动速度才能实现有序沉积。 相似文献
2.
3.
4.
5.
6.
7.
用静电纺丝法制备组织工程所需的纳米纤维及材料,在实验中主要研究了基本的工艺参数对所获纤维直径的影响。纤维或非织造膜由两种溶剂系统所制备:氯仿与N,N-二甲基甲酰胺(DMF)的混合剂及含少量(约40μg)嘧啶的乙酸溶液。为了研究聚合物浓度、DMF含量、施加电压、极距、溶剂系统等因素的影响,使用了扫描电子显微镜、溶液黏度仪、溶液电导率测试仪等。结果表明:随着聚合物浓度上升,纤维的直径先增加后减小;随着溶液中DMF含量的增加,纤维直径不断减小;电压对纤维直径无明显的影响;极距需适中,过大过小都会产生珠状纤维;含少量嘧啶(40μg的乙酸溶剂所获得的聚己内酯(PCL)纳米纤维比由氯仿和DMF的混合溶剂所获得的PCL纳米纤维更加细而均匀。 相似文献
8.
在聚己内酯(PCL)/冰乙酸(GAC)溶液体系中加入低毒低挥发性溶剂碳酸乙烯酯(EC),采用静电纺丝法成功制备纳米纤维,采用扫描电子显微镜研究了不同EC浓度对制得的纤维形貌和直径的影响。结果表明,当溶液中PCL质量分数为20%,EC体积分数从0%变化到9%时,纳米纤维数量增加,平均直径逐渐变小;当EC体积分数从9%变化到15%时,微米纤维或珠串状纤维数量开始增加,平均直径逐渐变大。对比研究了EC体积分数为9%的溶液与未加EC的溶液的纺丝稳定性,同时对比研究了由这两种溶剂分别制备的纳米纤维膜和微米纤维膜的结构和性能。结果表明,PCL/GAC/EC溶液体系黏度可在24h内保持稳定,满足连续电纺要求;X射线衍射测试结果表明两种纤维膜结晶构型一致,只是结晶度和晶粒大小有所区别;傅里叶变换红外光谱分析结果表明EC对PCL的化学结构没有影响;与微米纤维膜相比,纳米纤维膜的比表面积提高了362.6%,平均孔直径有所减小,接触角有所增大;纳米纤维膜的拉伸断裂应力稍大但断裂应变明显小于微米纤维膜。 相似文献
9.
10.
11.
熔体静电纺丝直写技术以其纤维直径、沉积形貌可控性高及无溶剂残留等优势,为高强度复杂形貌可控仿生组织工程(TE)支架的制备提供了巨大的空间,成为近年来的研究热点。本文首先简述了熔体静电纺丝直写技术相对于各类其他TE支架制备方法的优势;其次从工艺调控方面综述了熔体静电纺丝直写技术的工艺研究进展,并总结了实现复杂可控形貌TE支架的调控方法;随后从支架材料、形貌表征和细胞培养效果等方面综述了熔体静电纺丝直写技术的TE应用进展,并概括了该技术制备的TE拓扑结构支架的种类及特点;最后指出熔体静电纺丝直写技术具有广阔的研究前景,且该技术应以制备仿生、材料多样化以及复合支架为研究重点。 相似文献
12.
Melt electrospinning onto cylinders: effects of rotational velocity and collector diameter on morphology of tubular structures 下载免费PDF全文
Tomasz Jungst M Lourdes Muerza‐Cascante Toby D Brown Marco Standfest Dietmar W Hutmacher Jürgen Groll Paul D Dalton 《Polymer International》2015,64(9):1086-1095
Melt electrospinning writing is a direct‐writing additive manufacturing process that involves depositing a continuous, viscous and electrohydrodynamically stabilised molten jet onto a collector. Here, molten threads of medical‐grade polycaprolactone (PCL) are directed towards stationary/rotating cylindrical collectors (0–6600 rpm), including very slow revolutions well below the critical translation speed (approximately 600 mm min?1) of the molten jet. In this slow‐rotation region, the speed of the jet is faster than the movement of the collector and buckled/coiled fibres are produced due to compressive viscoelastic forces. The results are porous PCL tubes with wall morphologies often associated with viscoelastic liquids impinging onto a surface. The curvature of the collector affects how the fibre is deposited, with preferential fibre deposition along the axis of the cylinder. When the collector rotation speed is increased to greater than the speed of the jet, then straight fibres are produced. Such tubular structures have applications in tissue engineering. © 2015 Society of Chemical Industry 相似文献
13.
Cardiovascular disease is the leading cause of mortality worldwide. Therefore, new research strategies for the treatment of cardiovascular disease are required. Previously, extracellular matrices (ECMs) have been used alongside polymers to generate hybrid bioscaffolds. Herein, we propose combining aortic ECMs with a polycaprolactone electrospun scaffold and biomechanically evaluating the scaffolds. We electrospun three scaffolds with varying ECM concentrations and found that increasing the ECM concentration leads to decreased stiffness at low strains, increased elasticity at high strain, reduction in failure strain, and an increase in yield strength. We also noted a decrease in water droplet contact angle with the increasing ECM concentration. Furthermore, we found that all three scaffolds were capable of maintaining human umbilical vein endothelial cell attachment and survival. These findings show the wide spectrum of mechanical properties that can be achieved through the addition of different concentrations of ECM into the fibers. © 2019 The Authors. Journal of Applied Polymer Science published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48181. 相似文献
14.
Ultrafine fibers of bisphenol‐A polysulfone (PSF) were prepared by electrospinning of PSF solutions in mixtures of N,N‐dimethylacetamide (DMAC) and acetone at high voltages. The morphology of the electrospun PSF fibers was investigated by scanning electron microscopy. Results showed that the concentration of polymer solutions and the acetone amount in the mixed solvents influenced the morphology and the diameter of the electrospun fibers. The processing parameters, including the applied voltage, the flow rate, and the distance between capillary and collection screen, were also important for control of the morphology of electrospun PSF fibers. It was suggested that uniform ultrafine PSF fibers with diameter of 300–400 nm could be obtained by electrospinning of a 20 % (wt/v) PSF/DMAC/acetone (DMAC:acetone = 9:1) solution at 10–20 kV voltages when the flow rate was 0.66 ml h?1 and capillary–screen distance was 10 cm. Copyright © 2004 Society of Chemical Industry 相似文献
15.
Melt electrospinning writing (MEW), a computer-aided fiber deposition process based on an electrohydrodynamic working principle, enables the rational design and fabrication of fibrous scaffolds with micrometer thin fibers. So far, MEW has mainly been applied for poly(ε-caprolactone). Here we manufactured scaffolds of poly(2-ethyl-2-oxazoline), a hydrophilic polymer with high melting temperature, by MEW for the first time. We systematically varied and investigated the crucial instrument parameters: heating temperature (200–220 °C), feeding pressure (1.0–3.0 bar), accelerating voltage (3.0–7.0 kV) and collector distance (3.0–7.0 mm) in dependence of differently sized spinnerets (23 G, 25 G, 27 G, 30 G). As criteria for homogeneous deposition, we studied the resulting fiber diameters which could be adjusted from 8 μm to 138 μm and the corresponding variances. Furthermore this letter clarifies the need of a dynamic balance between involved mass flows in order to reduce pulsing failures of the jet and thereby structural defects of the deposited structures. 相似文献
16.
High rate of platelet adhesion and limited biocompatibility were regarded as the chief weaknesses of vascular tissue engineering scaffolds. The objective of this research was to overcome these drawbacks by ultilizing coaxial electrospinning to combine CDPS with PLA. CDPS and PLA were located at the inner and external layer respectively so that a “core-sheath” structure was formed. The properties of scaffolds were tested by methods such as mechanical testing, MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay and subcutaneous transplantation. Compared to natural tissues, CDPS/PLA coaxial scaffolds showed excellent biomechanic properties and hemocompatibility so that CDPS owned good potentiality in vascular tissue engineering. 相似文献
17.
Bin Zhang Alexander K. Nguyen Roger J. Narayan Jie Huang 《Journal of the American Ceramic Society》2022,105(3):1821-1840
Novel inks were formulated by dissolving polycaprolactone (PCL), a hydrophobic polymer, in organic solvent systems; polyethylene oxide (PEO) was incorporated to extend the range of hydrophilicity of the system. Hydroxyapatite (HAp) with a weight ratio of 55–85% was added to the polymer-based solution to mimic the material composition of natural bone tissue. The direct ink writing (DIW) technique was applied to extrude the formulated inks to fabricate the predesigned tissue scaffold structures; the influence of HAp concentration was investigated. The results indicate that in comparison to other inks containing HAp (55%, 75%, and 85%w/w), the ink containing 65% w/w HAp had faster ink recovery behavior; the fabricated scaffold had a rougher surface as well as better mechanical properties and wettability. It is noted that the 65% w/w HAp concentration is similar to the inorganic composition of natural bone tissue. The elastic modulus values of PCL/PEO/HAp scaffolds were in the range of 4–12 MPa; the values were dependent on the HAp concentration. Furthermore, vancomycin as a model drug was successfully encapsulated in the PCL/PEO/HAp composite scaffold for drug release applications. This paper presents novel drug-loaded PCL/PEO/HAp inks for 3D scaffold fabrication using the DIW printing technique for potential bone scaffold applications. 相似文献
18.
以三氯甲烷为溶剂,按聚乳酸(PLLA)/聚己内酯(PCL)质量比70/30配制质量分数3%的溶液进行静电纺丝,接收装置为转筒,电压为10 kV,接收距离为25 cm,推进速度为1.0 mL/h,制备PLLA/PCL有序纤维膜。通过对有序纤维膜进行扫描电镜、X射线衍射、动态力学性能以及力学性能测试,讨论了转筒的表面线速度对PLLA/PCL有序纤维膜性能的影响。结果表明:随着转筒表面线速度的增加,收集的有序纤维接近于平行排列,纤维的排列有序度提高;转筒表面线速度为3.75 m/s时,收集的有序纤维膜的晶粒尺寸及结晶度达到最大值,拉伸强度也达到最大值;转筒表面线速度大于3.75 m/s,收集的有序纤维膜的结晶度和晶粒尺寸减小,拉伸强度降低;转筒表面线速度为3.75 m/s时,得到的PLLA/PCL有序纤维膜的综合性能最好。 相似文献
19.
Carlos Mota Dario Puppi Matteo Gazzarri Paulo Bártolo Federica Chiellini 《Polymer International》2013,62(6):893-900
In the last decade, the melt‐electrospinning technique has gained attention for the production of highly porous microfibrous tissue engineering scaffolds. The possibility of processing polymers without the use of organic solvents is one of the main advantages over solution electrospinning. In this study, computer‐controlled melt‐electrospinning of a commercial poly(?‐caprolactone) and of two batches with different molecular weights of a three‐arm star poly(?‐caprolactone) by means of a screw‐extruder‐based additive manufacturing system is reported. Experimental parameters such as processing temperature, extrusion flow rate and applied voltage were studied and optimized in order to obtain non‐woven meshes with uniform fibre morphology. Applying the optimized parameters, three‐dimensional scaffolds were produced using a layer‐by‐layer approach (0 ? 90° lay‐down pattern). © 2013 Society of Chemical Industry 相似文献