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1.
The feasibility of using phosphate buffer saline (PBS)/ethanol mixtures as a benign solvent to electrospin three types of gelatin was studied. Gelatins with different chemical properties, such as Bloom, were selected and the effect of the gelatin nature and its concentration on the electrospinnability of the dope solution and on the fiber diameter of the electrospun mats were studied. Viscosity of the gelatin solution, which follows a power law relationship with the gelatin concentration, was found to significantly influence the morphology of the mats and the fiber diameter. It was demonstrated that the PBS/ethanol solvent interacted with the gelatins as a good solvent with a Flory exponent of 0.65. In addition, the effect of the solvent composition on the fiber formation process was evaluated corroborating that the ionic strength of the medium and the PBS/ethanol ratio significantly affected the morphology and the diameter of the electrospun fibers. Chemical structure and thermal stability of the electrospun gelatin mats were characterized by Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Finally, cytotoxicity of the electrospun mats was analyzed by the Alamar Blue assay, using human foreskin fibroblasts (BJ‐5ta), resulting in a high cell viability (80–90%) regardless the type of gelatin. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

2.
Collagen functionalized thermoplastic polyurethane nanofibers (TPU/collagen) were successfully produced by coaxial electrospinning technique with a goal to develop biomedical scaffold. A series of tests were conducted to characterize the compound nanofiber and its membrane in this study. Surface morphology and interior structure of the ultrafine fibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM), whereas the fiber diameter distribution was also measured. The crosslinked membranes were also characterized by SEM. Porosities of different kinds of electrospun mats were determined. The surface chemistry and chemical composition of collagen/TPU coaxial nanofibrous membranes were verified by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrometry (FTIR). Mechanical measurements were carried out by applying tensile test loads to samples which were prepared from electrospun ultra fine non-woven fiber mats. The coaxial electrospun nanofibers were further investigated as a promising scaffold for PIECs culture. The results demonstrated that coaxial electrospun composite nanofibers had the characters of native extracellular matrix and may be used effectively as an alternative material for tissue engineering and functional biomaterials.  相似文献   

3.
Flexible mats of titania fibers are prepared by calcination of electrospun polyvinylpyrrolidone fibers containing titanium isopropoxide precursor. Structural investigation of the calcinated nanofibers by X-ray diffraction (XRD) and electron diffraction (ED) combined with the morphologies by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) show the titania fibers, with an average diameter of 180 nm, were comprised of anatase and rutile crystals. The mechanical, chemical and thermal properties of the titania fiber mats are further investigated by the techniques of Instron mechanical tester, thermogravimetric analyzer (TGA), and Fourier transform infrared spectroscopy (FT-IR). The titania fiber mat prepared in this method exhibited a significant flexibility with 461 MPa Young’s modulus.  相似文献   

4.
This paper outlines the shrinkage of electrospun polyvinylpyrrolidone (PVP) fiber mats during thermal treatment. The thermal behavior and phase changes within the fibers were investigated by DSC and TGA/DTA. Five precursors with different PVP loading in ethanol were electrospun. The mats shrinkage as function of temperature was measured in the RT–200 °C range. Shrinkage rate drastically increased above the polymer glass transition point, Tg (150–180 °C), due to increase in polymer chain mobility. Mats shrinkage at 200 °C as function of PVP concentration showed a minimum at ∼10%wt. Below 10% PVP the mats morphology is non‐uniform, consisting of beads and fibers. Above 10% PVP, only flat and uniform fibers were observed. This paper outlines the dominant mechanism governing the mats shrinkage during heating. In addition, the effect of PVP concentration on the expansion of fibers diameter was investigated and found to be consistent with the linear shrinkage observing a minimum at ∼10% PVP. The effect of applied voltage on mat shrinkage was investigated, and showed a minimum at 12 kV. Understanding the interplay between fibers morphology and thermal shrinkage allows precursor composition and system optimization needed for minimizing shrinkage negative effects on the structure and properties of electrospun fiber mats. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 248–254  相似文献   

5.
This work evaluates the influence of electrospinning process parameters on the mean diameter and standard deviation of fiber diameters in electrospun poly(ethyl methacrylate) (PEMA). Processing conditions were selected using Taguchi’s statistical method. Oriented and unoriented electrospun mats with good mechanical properties were produced and demonstrated with tensile stress–strain diagrams. Differential scanning calorimetry (DSC) experiments showed that the polymer chains were forced into non-equilibrium conformations due to electrospinning. Enthalpic recovery during a heating scan is shown by an endothermic peak in the initial DSC heating scan that disappears in subsequent heating scans. An increase in the glass transition temperature with respect to PEMA films shows that the polymer is not equilibrated by heating above glass transition. Cell attachment was tested with MC3T3-E1 pre-osteoblastic cells cultured for short time periods on the electrospun mats. It is shown that the cells present less extended morphology with more diffuse perimetral focal adhesions than cells cultured on flat substrates. A tendency of cells to align in the direction of the substrate fibers in oriented electrospun membranes was also found.  相似文献   

6.
Biodegradable cell‐incorporated scaffolds can guide the regeneration process of bone defects such as physiological resorption, tooth loss, and trauma which medically, socially, and economically hurt patients. Here, 0, 5, 10, and 15 wt% fluoridated hydroxyapatite (FHA) nanoparticles containing 25 wt% F? and 75 wt% OH? were incorporated into poly(ε‐caprolactone) (PCL) matrix to produce PCL/FHA nanocomposite scaffolds using electrospinning method. Then, scanning electron microscopy (SEM), X‐ray diffraction (XRD) pattern, and Fourier transform infrared spectroscopy (FTIR) were used to evaluate the morphology, phase structure, and functional groups of prepared electrospun scaffolds, respectively. Furthermore, the tensile strength and elastic modulus of electrospun scaffolds were investigated using the tensile test. Moreover, the biodegradation behavior of electrospun PCL/FHA scaffolds was studied by the evaluation of weight loss of mats and the alternation of pH in phosphate buffer saline (PBS) up to 30 days of incubation. Then, the biocompatibility of prepared mats was investigated by culturing MG‐63 osteoblast cell line and performing MTT assay. In addition, the adhesion of osteoblast cells on prepared electrospun scaffolds was studied using their SEM images. Results revealed that the fiber diameter of prepared electrospun PCL/FHA scaffolds alters between 700 and 900 nm. The mechanical assay illustrated the mat with 10 wt% FHA nanoparticles revealed the highest tensile strength and elastic modulus. The weight loss alternation of mats determined around 1% to 8% after 30 days of incubation. The biocompatibility and cell adhesion of mats improved by increasing the amounts of FHA nanoparticles.  相似文献   

7.
刘海清 《高分子科学》2010,28(5):781-788
<正>The stability ofpoly(vinyl alcohol)(PVA) nanofibrous mats in water media was improved by post-electrospinning treatments.Bifunctional glutaraldehyde(GA) in methanol was used as a crosslinking agent to stabilize PVA nanofiber,but fiber twinning was observed frequently,and the highly porous structure of PVA nanofibrous mats was destroyed when the crosslinked fiber was soaked in water.To overcome this shortcoming,chitosan(CS) was introduced into the PVA spinning solution to prepare PVA/CS composite nanofibers.Their treatment in GA/methanol solution could retain the fiber morphology of PVA/CS nanofibers and porous structure of PVA/CS nanofibrous mats even if they were soaked in aqueous solutions for 1 month.Scanning electron microscopy(SEM),X-ray diffraction(XRD),thermal gravimetric analysis(TGA) and differential scanning calorimetry(DSC) were applied to characterize the physicochemical structure and thermal properties of PVA nanofibers.It was found that the water resistance of PVA nanofibrous mats was enhanced because of the improvement of the degree of crosslinking and crystallinity in the electrospun PVA fibers after soaking in GA/methanol solution.  相似文献   

8.
Ultra‐fine poly(vinyl alcohol) (PVA) electrospun fiber mats containing carbendazim were successfully fabricated by electrospinning from the neat PVA solution containing carbendazim in various amounts based on the weight of PVA. The morphological appearance of both the neat and the carbendazim‐loaded electrospun PVA fibers were smooth and the incorporation of carbendazim in the neat PVA solution did not affect the morphology of the resulting fibers. The average diameters of the neat and the carbendazim‐loaded electrospun PVA fibers ranged between 155 and 160 nm. The chemical integrity of the as‐loaded carbendazim in the carbendazim‐loaded electrospun PVA fiber mats was intact as verified by the 1H‐nuclear magnetic resonance spectroscopy. Thermal properties of the carbendazim‐loaded electrospun PVA fiber mats were analyzed by differential scanning calorimetry and thermogravimetric analysis. The release characteristics of the carbendazim‐loaded electrospun PVA mats were investigated by the total immersion method in distilled water at 30°C. The carbendazim‐loaded electrospun PVA mats exhibited greater amount of carbendazim released than the carbendazim‐loaded as‐cast films. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

9.
Randomly oriented fiber mats of chitosan–polyethylene oxide matrix reinforced with cellulose nanocrystals (CNCs) were prepared by electrospinning technique. The cellulose nanocrystals used were isolated using hydrochloric acid (CNCHCl) or sulphuric acid (\({\text{CNC}}_{{{\text{H}}_{ 2} {\text{SO}}_{ 4} }}\)) and the concentration of CNCs was 50 wt% in the electrospun mats. The surface characteristics of the nanocrystals were found to affect the dispersion, viscosity, conductivity and zeta-potential of the respective spinning solutions and resulted in better spinnability, homogeneity as well as crosslinking of CNCHCl based nanocomposite fiber mats compared to \({\text{CNC}}_{{{\text{H}}_{ 2} {\text{SO}}_{ 4} }}\) ones. The microscopy studies showed that the diameter of the electrospun fibers decreased with the inclusion of both types of nanocrystals and that crosslinking decreased the porosity of the mats. The tensile strength and tensile modulus of the mats increased with the addition of nanocrystals and increased further for the CNCHCl based mats (58 MPa, 3.1 GPa) after crosslinking. The as-spun CNCHCl based mats had average pore diameters of 1.6 μm and porosity of 38 %. The water vapor permeability and the O2/CO2 transmission increased with the addition of CNCHCl. The used nanocrystals as well as electrospun mats showed non-cytotoxic impact on adipose derived stem cells (ASCs), which was considered favorable for wound dressing.  相似文献   

10.
This study describes the preparation and characterization of nanofibrous mats obtained by electrospinning poly(ethylene terephthalate) (PET) solutions in trifluoroacetic acid/dichloromethane (TFA/DCM). Special attention was paid to the effect of polymer concentration and solvent properties on the morphology, structure, and mechanical and thermal properties of the electrospun nonwovens. The results show that the spinnable concentration of PET solution in TFA/DCM solvents is above 10 wt %. Mats have nanofibrous morphology with fibers having an average diameter in the range of 200–700 nm (depending on polymer concentration and solvent composition) and an interconnected pore structure. Higher solution concentration favors the formation of uniform fibers without beads and with higher diameter. Morphology and fiber assembly changed with the solvent properties. Solvent mixtures rich in TFA, i.e., those with higher dielectric constant and lower surface tension, originated fibers with small diameter. However, due to the lower volatility, those solvent mixtures also produced more branched and crosslinking fibers, with less morphologic uniformity. Mechanical properties (Young's modulus, ultimate strength, and elongation at break) and thermal properties (glass transition, crystallization, and melting) have been studied for the PET electrospun nanomats and compared with those of the original polymer. Solvent effect on fiber crystallinity was not significant, but a complex effect was observed on the mechanical properties of the electrospun mats, as a consequence of the different structural organization of the fibers within the mat network. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 460–471, 2008  相似文献   

11.
The Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats were fabricated by one-step electrospinning and ion-imprinting methods and their application as adsorbents for metal ions was also investigated.The resulting chitosan nanofiber mats were characterized by scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and thermal gravimetric analysis(TGA).The Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats were used as adsorbents for the removal of Pb(Ⅱ)ions from aqueous or acid solutions.The effects of p H values,contact time,content of crosslinker(glutaraldehyde)on Pb(Ⅱ)ions adsorption were studied.The results indicated that the Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats had the highest adsorption capacity of 110.0 mg/g at p H 7.The kinetic study demonstrated that the adsorption of Pb(Ⅱ)ions followed the pseudo-second-order model.The equilibrium isotherm data showed that the Langmuir model was the most suitable for predicting the adsorption isotherm of the studied system.The Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats had good adsorption selectivity,which illustrates the equilibrium adsorption capacity in the order of Pb(Ⅱ)Cu(Ⅱ)Zn(Ⅱ)Cd(Ⅱ)Ni(Ⅱ).The Pb(Ⅱ)ion-imprinting electrospun crosslinked chitosan nanofiber mats were stable and had good reuse ability.  相似文献   

12.
Polybenzoxazole (PBO) fibers with a submicron diameter were successfully prepared by electrospinning its precursor, polyhydroxyamide (PHA), solutions to obtain the PHA fibers first, followed by appropriate thermal treatments for cyclization reaction. BisAPAF‐IC PHA with two different molecular weights (MWs) were synthesized from a low temperature polymerization of 2,2′‐bis(3‐amino‐4‐hydroxyphenyl) hexafluoropropane (BisAPAF) and isophthaloyl chloride (IC). Using dimethylacetamide (DMAc) and tetrahydrofuran (THF), solvent effects on the electrospinnability of PHA solutions were investigated. For balancing the solution properties, it was found that DMAc/THF mixture with a weight ratio of 1/9 was the best cosolvent to prepare smooth PHA fibers; uniform PHA fibers with a diameter of 325–720 nm were obtained by using 20 wt % PHA/(DMAc/THF) solutions. For a fixed PHA concentration, solutions with a lower MW of PHA yielded thinner electrospun fibers under the same electrospinning condition. After obtaining the electrospun BisAPAF‐IC PHA fibers, subsequent thermal cyclization up to 350 °C produced the corresponding thermally stable BisAPAF‐IC PBO fibers with a diameter of 305–645 nm. The structure of the precursor fibers and the fully cyclized fibers were characterized by FTIR. For the cyclized BisAPAF‐IC PBO fibers, thermogravimetric analysis showed a 5% weight loss temperature at 523 °C in nitrogen atmosphere. The interconnected fiber structure in the BisAPAF‐IC PBO fiber mats was irrelevant to the curing process, but resulted from the jet merging during the whipping process as revealed by the high speed camera images. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 8159–8169, 2008  相似文献   

13.
Nanostructured biocomposite scaffolds of poly(l-lactide) (PLLA) blended with collagen (coll) or hydroxyapatite (HA), or both for tissue engineering application, were fabricated by electrospinning. The electrospun scaffolds were characterized for the morphology, chemical and tensile properties by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), water contact angle (WCA), Fourier transform infrared (FTIR) measurement, and tensile testing. Electrospun biocomposite scaffolds of PLLA and collagen or (and) HA in the diameter range of 200-700 nm mimic the nanoscale structure of the extracellular matrix (ECM) with a well-interconnection pore network structure. The presence of collagen in the scaffolds increased their hydrophility, and enhanced cell attachment and proliferation, while HA improved the tensile properties of the scaffolds. The biocompatibility of the electrospun scaffolds and the viability of contacting cells were evaluated by 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) nuclear staining and by fluorescein diacetate (FDA) and propidium iodide (PI) double staining methods. The results support the conclusion that 293T cells grew well on composite scaffolds. Compared with pure PLLA scaffolds a greater density of viable cells was seen on the composites, especially the PLLA/HA/collagen scaffolds.  相似文献   

14.
A series of multi-block copolymers, poly(L-lactide)-b-poly (?-caprolactone) (PLLA-b-PCL) were synthesized. The first step of the synthesis consisted of the transesterification between the PLLA and 1,4-Butanediol, followed by the copolymerization of PLLA-diols and PCL, using isophorone diisocyanate (IPDI) as a coupling agent. The synthesized polymers were characterized by Fourier transform infrared (FTIR) spectra, differential scanning calorimetry (DSC) and wide angle X-ray diffraction (WAXD). PLLA/PCL block copolymers were electrospun into ultrafine fibers. The morphology of the electrospun fibrous scaffolds were investigated by Scanning Electron Microscopy (SEM). Results showed that the morphology and diameter of the fibers were affected by the electrospinning solution concentrationan and different weight ratio of PLLA/PCL. These electrospun PLLA-b-PCL fibrous membranes exhibited good flexibility and deformability. In comparison with the electrospun PLLA membrane, the electrospun fibrous membranes of PLLA-b-PCL demonstrated an enhanced elongation with still high tensile strength and Young's modulus to be beneficial for tissue engineering scaffolds.  相似文献   

15.
静电纺丝法制备聚甲醛纳米纤维   总被引:9,自引:0,他引:9  
以六氟异丙醇为溶剂, 用静电纺丝的方法制备了聚甲醛纳米纤维. 利用场发射扫描电镜对纤维形貌进行了表征, 纤维的直径为0.3~1.2 μm. 讨论了溶液浓度、接收距离、电压和温度等纺丝参数对纤维形貌的影响. 用DSC方法对电纺纤维膜的结晶性能进行了研究, 并与溶液浇铸膜的进行了比较. 结果表明, 电纺纤维膜的熔点与溶液浇铸膜的相同, 与溶液的浓度无关, 但结晶度比溶液浇铸膜的低. 力学性能用拉伸试验进行了测试, 观察到很长的断裂伸长率.  相似文献   

16.
In this work, we studied solvent-induced polymer degradation and its effect on the morphology of electrospun fibers. Nylon-6 in formic acid solvent was allowed to degrade by simply allowing it to stand for a long time, and nanofibrous mats were fabricated by taking a fraction of this solution at different time intervals via electrospinning under the same electrospinning conditions. FE-SEM images of the mats indicate that the nanofiber diameter gradually decreased with the standing time of solution, and large numbers of true nano fibers (<50 nm in diameter) were obtained. MALDI-TOF analysis revealed that the formation of low-molecular weight ions was caused by solvent degradation. FT-IR, DSC, XRD, and TGA analyses of electrospun mats showed that some physical properties, such as bond strength, crystallinity, and thermal stability also depended on solvent degradation. The obtained sub-nanofibrous mat has potential applications in different bioengineering fields.  相似文献   

17.
Submicron poly(vinyl alcohol) (PVA) fiber mats were prepared by electrospinning of aqueous PVA solutions in 6-8% concentration. Fiber morphology was observed under a scanning electron microscope and effects of instrument parameters including electric voltage, tip-target distance, flow rate and solution parameters such as concentration on the morphology of electrospun PVA fibers were evaluated. Results showed that, when PVA with higher degree of hydrolysis (DH) of 98% was used, tip-target distance exhibited no significant effect on the fiber morphology, however the morphological structure can be slightly changed by changing the solution flow rate. At high voltages above 10 kV, electrospun PVA fibers exhibited a broad diameter distribution. With increasing solution concentration, the morphology was changed from beaded fiber to uniform fiber and the average fiber diameter could be increased from 87 ± 14 nm to 246 ± 50 nm. It was also found that additions of sodium chloride and ethanol had significant effects on the fiber diameter and the morphology of electrospun PVA fibers because of the different solution conductivity, surface tension and viscosity. When the DH value of PVA was increased from 80% to 99%, the morphology electrospun PVA fibers was changed from ribbon-like fibers to uniform fibers and then to beaded fibers. The addition of aspirin and bovine serum albumin also resulted in the appearance of beads.  相似文献   

18.
A poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) fibrous surface with various bead-on-string structures was fabricated by electrospinning. PHBV was electrospun at various concentrations and then CF4 plasma treatment was employed to further improve the hydrophobicity of the PHBV fiber surfaces. The surface morphology of the electrospun PHBV mats was observed by scanning electron microscopy (SEM). The surface properties were characterized by water contact angle (WCA) measurements and X-ray photoelectron spectroscopy (XPS). The surface morphology of the electrospun PHBV fibrous mats with the bead-son-string structure varied with the solution concentration. The WCA of all of the electrospun PHBV mats was higher than that of the PHBV film. In particular, a very rough fiber surface including porous beads was observed when PHBV was electrospun from the solution with a concentration of 26 wt%. Also, its WCA further increased from 141 degrees to 158 degrees after CF(4) plasma treatment for 150 s. PHBV can be rendered superhydrophobic by controlling the surface morphology and surface energy, which can be achieved by adjusting the electrospinning and plasma treatment conditions.  相似文献   

19.
We evaluated the effects of the solvent composition with respect to the solution concentration, applied electric field, and tip‐to‐collector distance on the morphology of electrospun poly(vinyl chloride) (PVC) fibers. The solvent volume ratio was strongly correlated with the diameter of the electrospun fibers with respect to the other processing parameters. Electrospun PVC fibers dissolved in tetrahydrofuran (THF) had diameters ranging from 500 nm to 6 μm; those dissolved in N,N‐dimethylformamide (DMF) had an average diameter of 200 nm. The diameters of the electrospun fibers were obtained from narrow to broad distributions with the solvent composition. Also, the diameters of fibers electrospun from a mixed solvent of THF and DMF were less than 1 μm. The mechanical properties of electrospun PVC nonwoven mats depended on the fiber orientation and linear velocity of the drum surface. With increasing linear velocity of the drum surface, electrospun PVC fibers were arranged toward the machine direction, and the dimensions of the spiral path were shorter. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 2259–2268, 2002  相似文献   

20.
In the paper, we successfully prepared spider silk fibroins (Ss)/poly( d, l-lactide) (PDLLA) composite fibrous nonwoven mats for the first time to the best of our knowledge. The morphology of the fibers was observed by a scanning electron microscope (SEM) and transmission electron microscope (TEM). The secondary structure change of the spidroin before and after electrospinning was characterized using Fourier transform infrared spectroscopy (FT-IR). Herein, a qualitative analysis of the conformational changes of the silk protein was performed by analyzing the FT-IR second-derivative spectra, from which quantitative information was obtained via the deconvolution of the amide I band. A mechanical test was carried out to investigate the tensile strength and the elongation at break. A water contact angle (CA) measurement was also performed to characterize surface properties of the fibers. The cytotoxicity of electrospun PDLLA and Ss-PDLLA nonwoven fibrous mats was evaluated based on a CCL 81(Vero) cells proliferation study. The results showed that the hydrophilic and mechanical property of the composite fiber were improved by introducing spidroin.  相似文献   

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