PBS-SF核-壳结构复合超细纤维膜的制备及性能

利用同轴静电纺丝方法, 制备聚丁二酸丁二酯(PBS)-丝素蛋白(SF)核-壳结构复合超细纤维膜, 并对复合超细纤维膜进行FE-SEM、 TEM形态表征, 分析了内层纺丝流率对纤维形貌的影响; 通过FTIR和XRD测试, 比较了甲醇处理前后复合超细纤维膜分子结构和结晶性能的变化, 并进行力学性能测试。结果表明: 通过对纤维核层PBS、 壳层SF和横截面的观察, 复合超细纤维有明显的核-壳结构, 可以清晰看出纤维的核层PBS和壳层SF; 随着核层纺丝流率的增大, 超细纤维的平均直径增大; 甲醇处理后, 复合超细纤维膜中壳层SF分子结构由无规构象转变为β-折叠构象, 复合超细纤维膜核层衍射吸收强度减小, 但整个核-壳结构复合超细纤维膜结晶性能无明显变化; 甲醇处理后拉伸破坏应力从14.9 MPa增大到17.2 MPa, 但拉伸破坏应变从96.8%减小到81.8%。      

PLGA载药纤维的制备及释药行为研究

PLGA(聚乳酸/乙醇酸共聚物)具有良好的生物降解性、相容性和降解产物无毒性等优点,且降解速率可由其分子量和共聚物组成比例来调控.本文采用静电纺丝法制备了以PLGA为壳层材料,聚乙烯基吡咯烷酮(PVP)、PLGA为内芯材料的同轴复合纤维,并研究了两种药物(5-氟尿嘧啶和番荔素)在纤维载体中的药物释放行为.在相同的释放环境中,与混纺纤维比较,同轴电纺得到负载了5-氟尿嘧啶的纤维在初期药物突释行为有所改善.同时,对于负载番荔素的同轴复合纤维,不同芯材样品能够表现出不同的释放行为.     

有序PEO/PHB核壳超细纤维的制备及性能

以聚氧乙烯(PEO)/氯仿溶剂为核层纺丝液,聚β-羟基丁酸酯(PHB)/氯仿溶剂为壳层纺丝液,通过同轴静电纺丝技术和高速旋转接收辊制备了有序排列的PEO/PHB核壳超细纤维.采用扫描电镜(SEM)、透射电镜(TEM)、差示扫描量热仪(DSC)、热重分析仪(TGA)、X射线衍射仪(XRD)和动态热机械分析仪(DMA)对制备的PEO/PHB核壳超细纤维膜的表面形貌、核壳结构、热性能、结晶性能和力学性能进行表征.结果表明:实验制备的PEO/PHB纤维具有显著的核壳结构,纤维排列有序,纤维平均直径为0.57～1.27μm;PEO/PHB核壳超细纤维晶体结构中含有组分PHB的α型晶体和组分PEO的单斜晶体;增加纺丝电压,纤维直径减小,结晶度先增大后减小;增加推注速度,纤维直径增大,结晶度先增大后减小;增加收集距离,纤维直径先减小后增大,结晶度先增加后减小.改变单一纺丝条件,在纺丝电压18 kV或推注速度0.07 mm/min或收集距离8 cm的条件下所制备的纤维膜均具有较高的力学性能;与纯PHB纤维和纯PEO纤维比较,有序排列PEO/PHB核壳超细纤维中各组分热学稳定性均有所提高.     

温敏性聚己内酯-聚N-异丙基丙烯酰胺作为抗癌药物载体的制备与药物释放的研究

以卟啉衍生物为内核,采用可逆加成-断裂链转移(RAFT)聚合法合成了温度敏感性聚己内酯-聚N-异丙基丙烯酰胺。用FT-IR、1 H NMR、GPC、TEM、分子荧光、变温紫外、粒度分布等手段对聚合物进行了表征,并以紫杉醇为模型药物分子,进行了药物释放测试。结果表明,聚合物自组装后,形成了平均直径为100nm左右的胶束。这种内部亲脂外部亲水的核壳结构能够稳定地载药,在温度为15℃的DMF中,12h内释放了37%的药物,而在温度为38℃的DMF中,12h药物释放量为81.4%。这种两亲性大分子聚合材料对紫杉醇的释放具有温度敏感性,有望在抗癌药物的控制释放领域得到广泛应用。     

静电纺丝制备聚合物超细纤维的研究及应用

静电纺丝是一种制备聚合物超细纤维的有效方法,并可直接获得直径达5～500nm的超细纤维膜.综述了静电纺丝的发展过程、基本原理和研究现状,介绍了静电纺丝超细纤维膜微观形貌的影响因素及其应用前景.     

同轴静电纺丝制备PCL-PLA芯-壳结构复合纤维及其形态分析

本文采用同轴静电纺丝技术制备聚己内酯(PCL)-聚乳酸(PLA)芯-壳结构复合纤维。通过扫描电子显微镜(SEM)观察芯层-壳层溶液推进速度、纺丝电压和收集距离对PCL-PLA复合纤维形貌的影响;通过透射电子显微镜(TEM)分析芯层-壳层溶液推进速度比对PCL-PLA芯-壳结构形成的影响。结果表明:当壳层溶液推进速度大于芯层时,形成了完整的芯-壳结构;另外,随着壳层溶液推进速度的增加,PCL-PLA复合纤维芯层含量降低;随着纺丝电压和收集距离的增加,PCL-PLA复合纤维平均直径减小。     

芯壳结构竹塑复合材料密度及微观结构的CT分析

以竹屑、高密度聚乙烯(HDPE)、竹浆纤维、纳米碳酸钙及白泥为主要材料,采用聚合物共挤出技术制备芯壳结构竹塑复合材料。利用Micro-CT扫描技术对复合材料内部结构进行了观测,同时还对断面密度进行了分析。结果表明,通过对不同壳层材料的复合材料断面CT图像进行二值化处理后,可清晰地反映复合材料内部缺陷。Micro-CT三维空间分析技术能够实现对4种不同壳层材料的芯壳结构竹塑复合材料的内部微观结构可视化的精细表征,且重建密度表现出与实测密度趋势一致。壳层加入白泥或纳米碳酸钙的复合材料的剖面密度在厚度方向上呈现出壳层密度高而芯层密度低。不同壳层材料的复合材料CT图像阈值分布在26.1到95.6之间,在此基础上建立了CT图像阈值与密度的关系。     

同轴共纺技术制备聚苯乙烯中空亚微米纤维

利用同轴静电纺丝技术制备出壳层为聚苯乙烯(PS),芯层为聚乙烯吡咯烷酮(PVP)的壳-芯结构复合纤维,通过除去芯层PVP,成功地制备出了PS中空亚微米纤维。并对其进行了TEM、SEM测试。结果表明,纺丝过程中内、外液流速比值K直接影响着复合泰勒锥的形成及复合纤维的微观形态,且复合纤维平均直径随K值的增大而减小。     

尼龙6/聚乙烯醇超细纤维无纺布的制备与表征

静电纺丝是一种有效制备超细纤维的重要方法。本文应用同轴静电纺丝装置制备出外层为尼龙6(N y lon 6),内层为聚乙烯醇的壳-芯结构的复合功能型无纺布。通过TEM、SEM、红外光谱、力学性能表征探讨了它们的性能,同时将其应用到棉布衬里,测试其透湿性能。以期用于过滤膜、防护服及医疗纺织材料等领域。     

静电纺制备负载环丙沙星聚乳酸己内酯纳米纤维膜

静电纺丝可简单有效地制备聚合物纳米纤维。所得纤维具有多孔结构和较高的比表面积,在组织工程、伤口敷料及生物医药等方面具有潜在用途。通过静电纺丝技术,制备载药聚乳酸己内酯(PLCL)纳米纤维膜,载入抗菌型药物环丙沙星,应用于伤口敷料。采用傅里叶红外光谱仪、扫描电子显微镜和接触角等表征手段对载药前后的纳米纤维膜进行表征。扫描电子显微镜观察到纤维膜表面光滑,载药后纤维直径变小。抗菌及药物释放实验表明纤维膜具有抗菌性,在药物释放上可起到缓释效果,此纤维材料有望应用在伤口敷料上。     

Controlled dual release of hydrophobic and hydrophilic drugs from electrospun poly(l-lactic acid) fiber mats loaded with chitosan microspheres

This work is to develop novel electrospun poly(l-lactic acid) (PLLA) fiber mats for controllable delivery of hydrophobic and hydrophilic drugs. For this aim, bovine serum albumin (BSA, used as a hydrophilic model drug) was firstly enveloped into chitosan microspheres by spray drying. Benzoin (used as a hydrophobic model drug) was directly dissolved in PLLA solution and then the chitosan microspheres were suspended into the PLLA solution, which was used to prepare PLLA fiber mats by electrospinning. Polyvinylpyrrolidone (PVP) was added into the PLLA solution to tune the drug release behaviors. The results showed that the chitosan microspheres were uniformly distributed in the fibers. BSA had a short-term release while benzoin had a long-term and sustained release in all the dual drug delivery systems, and the release of both hydrophobic and hydrophilic drugs could be adjusted by changing the ratio of PVP/PLLA.     

Silk microfibrous mats with long-lasting antimicrobial function

The controlled release of antibiotic drugs to injured sites has great advantages over the conventional intravenous administration of antibiotics,which is associated with systemic toxicity,for wound care.Electrospun nanofibrous/microfibrous mats,with a similar structure to the native extracellular matrix,is a promising wound dressing.Herein,drug-loaded halloysite nanotubes(HNTs)incorporated into regenerated silk fibroin(RSF)microfibrous mats were prepared by electrospinning to achieve sustained drug release and long-lasting antimicrobial protection.A broad-spectrum antibiotic,tetracycline hydrochloride(TCH),was selected as the model drug.Transmission electron microscopic images revealed that the TCH-loaded HNTs were homogeneously embedded in the RSF electrospun microfibers without significant changes in morphology.The drug release profiles showed that the RSF microfibrous mats with TCH-loaded HNTs exhibited a significantly reduced burst phase and a long release time over two weeks compared to the pure TCH-loaded HNTs and the TCH-loaded RSF microfibrous mats without HNTs.These results were attributed to the two-step release of TCH first from the HNTs and then RSF matrix in the electrospun mats.Finally,the antimicrobial properties of the RSF microfibrous mats with TCH-loaded HNTs were evaluated using both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli bacteria.The results demonstrated long-lasting antimicrobial activity for at least one week,showing the great potential of TCH-loaded RSF microfibrous mat as a wound dressing material.Therefore,these TCHloaded RSF microfibrous mats with excellent biocompatibility and sustained antimicrobial protection are extremely attractive systems for clinical applications.     

聚碳酸酯/TiO2超细纤维的制备与表征

静电纺丝是一种有效制备超细纤维的重要方法.以钛酸丁酯作为TiO2前驱体实现了聚碳酸酯（PC）/TiO2的制备,采用TEM、SEM、红外光谱、X射线衍射等方法进行理化性能表征,并测试了材料的抗菌性能.结果表明：当PC与钛酸丁酯质量比为9∶1时电纺纤维尺寸较均匀,珠状物最少;7∶3时纤维膜对大肠杆菌的抗菌率达到87%左右,以期用于过滤膜、防护服及医疗纺织材料等领域.     

Tetracycline hydrochloride (TCH)-loaded drug carrier based on PLA:PCL nanofibre mats: experimental characterisation and release kinetics modelling

The experimental characterisation of electrospun poly(lactic acid) (PLA):poly(ε-caprolactone) (PCL) as drug carriers, at five blend ratios from 1:0, 3:1, 1:1, 1:3 and 0:1, was holistically investigated in terms of their morphological structures, crystallinity levels and thermal properties. A widely used antibiotic tetracycline hydrochloride (TCH) was loaded to prepared fibrous mats at TCH concentrations of 1 and 5 wt%. The additional TCH into PLA:PCL better facilitates the reduction of fibre diameter than polymer blends. Increasing the TCH concentration from 1 to 5 wt% was found to result in only a modest decrease in the crystallinity level, but a significant increase in the crystallisation temperature (T _c) for PLA within PLA:PCL blends. The infrared spectra of fibre mats confirm the successful TCH encapsulation into fibrous networks. The first order and Zeng models for drug release kinetics were in better agreement with experimental release data, indicating the release acceleration of TCH with increasing its concentration. In a typical case of PLA:PCL (1:1) loaded with 5 wt% TCH, the fibre mats apparently demonstrate more wrinkled and floppy structures and increased fibre diameters and decreased inter-fibrous spaces after 7-day in vitro fibre degradation, as opposed to those obtained after 3-h degradation.     

Electrospun poly(l-lactide)/zein nanofiber mats loaded with <Emphasis Type="Italic">Rana chensinensis</Emphasis> skin peptides for wound dressing

Electrospun nanofiber mats can display impressive performance as an ideal wound dressing. In this study, poly(l-lactide)(PLLA)/zein nanofiber mats loaded with Rana chensinensis skin peptides (RCSPs) were successfully produced by two different electrospinning techniques, blend and coaxial, with the goal of developing a wound dressing material. The nanofiber mats were investigated by environmental scanning electron microscope (ESEM), transmission electron microscopy (TEM), fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), water contact angle, mechanical tests and cell viability. The resulting nanofiber mats exhibited smooth surfaces, tiny diameters and different cross-sectional shapes from pure PLLA and zein nanofibers. The FTIR result showed that PLLA, zein and RCSPs were well dispersed, without chemical interactions. Compared with coaxial nanofiber mats, blending zein-RCSPs with PLLA enhanced hydrophilicity but decreased mechanical properties. Adding RCSPs into the electrospun nanofibers significantly improved the mechanical properties of the mats. Cell viability studies with human foreskin fibroblasts demonstrated that cell growth on PLLA/zein-RCSPs nanofiber mats was significantly higher than that on PLLA/zein nanofiber mats. The results indicate that nanofiber mats containing RCSPs are potential candidates for wound dressing.     

Fabrication and characterization of biodegradable nanofibrous mats by mix and coaxial electrospinning

The aim of this study is to investigate an innovative tissue engineering scaffold with a controllable drug-releasing capability. The hypothesis is that the nanofibers fabricated by coaxial electrospinning could encapsulate and release sustainedly Tetracycline Hydrochloride (TCH). To testify the hypothesis, nanofibers were prepared by coaxial electrospinning from Poly(l-lactid-co-ε-caprolactone) [PLLACL]/2,2,2-Frifluoroethanol (TFE) solutions (as the shell solutions) and TCH/TFE solutions (as the core solutions). In addition, nanofibers of PLLACL-blend-TCH were also prepared as the control by mix electrospinning. The relationship between fibers morphologies and processed conditions in electrospinning were investigated. TCH release behaviors from the nanofibrous mats were studied. The antibacterial properties of aforementioned nanofibers were detected by the Escherichia coli growth-inhibiting tests. The results indicated that the nanofibers prepared by coaxial-electrospinning had the desired and controllable TCH encapsulation/release profile; thus, it could be utilized as both a drug encapsulation/release vehicle and a tissue engineering scaffold.     

Deposition of the fractal-like gold particles onto electrospun polymethylmethacrylate fibrous mats and their application in surface-enhanced Raman scattering

The ultrafine polymethylmethacrylate fibers containing gold nanoparticles have been prepared by using the electrospinning technique. Then the continuously coarse gold films formed by fractal-like thorny gold particles were deposited on the organic eletrospun fiber surface by an electroless process. The morphology of coarse gold films was characterized by scanning electron and transmission electron microscopy. The results revealed that the morphology of the gold particles was affected not only by the amount of gold seeds embedded in the organic fibers but also by the amount of gold deposited on the fiber's surfaces. The surface-enhanced Raman scattering (SERS) effect of the fibrous mats coated with gold films was evaluated by using Rhodamine B as an adsorbate. The results indicated that this kind of fibrous mat exhibited high and reproducible SERS activity and could be developed as highly sensitive SERS substrate.     

A synthetic polypeptide electrospun biomaterial

Fiber mats of a synthetic anionic copolypeptide of l-glutamic acid and l-tyrosine (PLEY) have been produced by electrospinning, and physical, chemical, and biological properties of the fibers have been characterized in vitro. Fibers were obtained from polymer dissolved in water at concentrations of 20-60% (w/v) but not below this range. Applied voltage and spinneret-collector distance were also found to influence polymer spinnability. Oriented fibers were obtained by changing the geometry of the collector. Fiber diameter was measured by scanning electron microscopy (SEM). A common chemical reagent was used to cross-link polymers postspinning. Fiber solubility in aqueous solution varied as a function of cross-linking time. Cationic polypeptides labeled with a fluorescent dye became noncovalently associated with cross-linked fibers, enabling visualization by fluorescence microscopy. Spectroscopy provided information on polymer chain conformation in solution and in fibers. Degradation of cross-linked fibers by different proteases has been demonstrated. Fibroblasts were cultured on cross-linked fiber mats to test basic cytocompatibility. Synthetic polypeptide fiber mats may be useful in applications in medicine, biotechnology, and other areas.     

载药电纺丝素蛋白纤维毡的结晶含量对其药物释放的影响

以水溶液体系的再生丝素蛋白为原料,利用静电纺丝技术制备了载罗丹明B的丝素蛋白纤维毡。利用甲醇水溶液对其进行后处理,考察了不同处理时间下丝素蛋白的结晶含量对药物释放的影响。通过水溶性质量损失率、接触角、扫描电镜、傅里叶红外光谱、X射线衍射光谱及紫外光谱对处理前后的丝素蛋白纤维毡的表面形貌和结构以及药物释放行为进行了表征。结果表明,随着甲醇水溶液处理时间的延长,电纺丝纤维的质量损失率减小,亲水性减弱,丝纤维中的Silk II结晶(由β-折叠结构组成)含量增加,药物释放速率也增加。即通过控制处理时间,可以控制丝纤维中Silk II结晶的含量,从而控制药物的释放速率。     

聚乳酸/杆菌肽静电纺丝纤维的体外释药研究

为探讨聚乳酸纤维结构形貌对杆菌肽药物的缓慢释放行为及作用机理,通过静电纺丝法制备了聚乳酸/杆菌肽单轴纤维、聚乳酸/杆菌肽串珠和(聚乳酸/杆菌肽)-聚乳酸同轴核-壳纤维等聚乳酸/杆菌肽药物缓释体系,并采用红外光谱法和差热分析法对其化学结构和热性能进行了表征.利用紫外分光光度计法研究了不同载药体系的体外药物释放行为,并探索了不同降解时期载药纤维的质量和形貌变化规律.研究表明:杆菌肽与聚乳酸主要为物理结合;聚乳酸单轴纤维和串珠对杆菌肽的扩散释放机理,属于纯Fick扩散;采用单轴和同轴静电纺丝技术可以获得两种不同释药特性的载药纤维.单轴纤维和串珠能够将药物快速释放,适合抗生素的治疗;同轴纤维中药物受控释放,更适合长期、小剂量的药物释放.