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Sample records for electrospun tio2 nanofibers

  1. Properties of Electrospun TiO2 Nanofibers

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    Bianca Caratão

    2014-01-01

    Full Text Available Titanium oxide filled polyvinylpyrrolidone (PVP composite nanofibers have been prepared via a simple electrospinning technique. The combination of good TiO2 properties with its high surface area leads these nanofibers into having a vast applicability such as cosmetics, scaffolds for tissue engineering, catalytic devices, sensors, solar cells, and optoelectronic devices. The structural and chemical properties of the prepared samples have been studied. The presence of the TiO2 phase on the nanofibers was confirmed. An anatase to rutile transformation was observed at 600°C. Regarding the thermogravimetric and differential thermal analysis (TGA/DTA, the TIP decomposition and the PVP evaporation at 225°C were verified.

  2. Electrospun nylon-6 spider-net like nanofiber mat containing TiO(2) nanoparticles: a multifunctional nanocomposite textile material.

    Science.gov (United States)

    Pant, Hem Raj; Bajgai, Madhab Prasad; Nam, Ki Taek; Seo, Yun A; Pandeya, Dipendra Raj; Hong, Seong Tshool; Kim, Hak Yong

    2011-01-15

    In this study, electrospun nylon-6 spider-net like nanofiber mats containing TiO(2) nanoparticles (TiO(2) NPs) were successfully prepared. The nanofiber mats containing TiO(2) NPs were characterized by SEM, FE-SEM, TEM, XRD, TGA and EDX analyses. The results revealed that fibers in two distinct sizes (nano and subnano scale) were obtained with the addition of a small amount of TiO(2) NPs. In low TiO(2) content nanocomposite mats, these nanofiber weaves were found uniformly loaded with TiO(2) NPs on their wall. The presence of a small amount of TiO(2) NPs in nylon-6 solution was found to improve the hydrophilicity (antifouling effect), mechanical strength, antimicrobial and UV protecting ability of electrospun mats. The resultant nylon-6/TiO(2) antimicrobial spider-net like composite mat with antifouling effect may be a potential candidate for future water filter applications, and its improved mechanical strength and UV blocking ability will also make it a potential candidate for protective clothing. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. A metal matrix composite prepared from electrospun TiO2 nanofibers and an Al 1100 alloy via friction stir processing.

    Science.gov (United States)

    Zhang, Lifeng; Chandrasekar, Ramya; Howe, Jane Y; West, Michael K; Hedin, Nyle E; Arbegast, William J; Fong, Hao

    2009-05-01

    Electrospun TiO2 nanofibers, consisting of anatase phase TiO2 single-crystalline crystallites with sizes of approximately 10 nm, were impregnated into an Al 1100 alloy by the technique of friction stir processing (FSP). The studies of the resulting TiO2-Al composite revealed that the electrospun TiO2 nanofibers with diameters of approximately 200 nm were broken into nanoparticles during FSP; the in situ generated pristine surfaces led to the interfacial reaction between TiO2 and Al and resulted in the formation of strong interfaces between the electrospun TiO2 nanoparticles and the Al 1100 matrix. This was evidenced by the fact that the filler-matrix fracture always occurred on the Al matrix side in the interfacial region. Consequently, the TiO2-Al composite made from the electrospun TiO2 nanofibers possessed a significantly higher Vickers hardness than that made from a commercially available anatase phase TiO2 nanopowder, of which the organic and/or carbonaceous contaminants on the surface impeded the interfacial reaction between TiO2 and Al during FSP.

  4. Integration of adsorption and reduction for uranium uptake based on SrTiO3/TiO2 electrospun nanofibers

    Science.gov (United States)

    Hu, Lin; Yan, Xue-Wu; Zhang, Xue-Ji; Shan, Dan

    2018-01-01

    The integration of adsorption and reduction for uranium uptake via photoelectrochemical method was conducted based on hetero-structure SrTiO3/TiO2 electrospun nanofibers. The SrTiO3/TiO2 was fabricated by two steps. First, TiO2 nanofibers were prepared via electrospinning, and then the SrTiO3 cubes grew on the surface of TiO2 nanofibers to form heterostructure by in situ hydrothermal treatment. For the uranium uptake based on photoelectrochemical method, the FTO electrodes modified by SrTiO3/TiO2 electrospun nanofibers removed uranium concentration by 81 ppm, higher than TiO2 nanoparticles, SrTiO3 nanoparticles and TiO2 electrospun nanofibers (59 ppm, 40 ppm and 70 ppm respectively). Besides, the photocurrent of these materials was also measured through photoelectrochemical measurements. Meanwhile, surface analyses using various techniques (Scanning electron microscopic, Transmission electron microscope and X-ray photoelectron spectroscopy) was also performed. Finally, the mechanism of electron transfer between SrTiO3/TiO2 and uranium was proposed.

  5. Characterization and optimization of electrospun TiO2/PVP nanofibers using Taguchi design of experiment method

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    H. Albetran

    2015-09-01

    Full Text Available TiO2 nanofibers were prepared within polyvinylpyrrolidone (PVP polymer using a combination of sol–gel and electrospinning techniques. Based on a Taguchi design of experiment (DoE method, the effects of sol–gel and electrospinning on the TiO2/PVP nanofibers’ diameter, including titanium isopropoxide (TiP concentration, flow rate, needle tip-to-collector distance, and applied voltage were evaluated. The analysis of DoE experiments for nanofiber diameters demonstrated that TiP concentration was the most significant factor. An optimum combination to obtain smallest diameters was also determined with a minimum variation for electrospun TiO2/PVP nanofibers. The optimum combination was determined to be a 60% TiP concentration, at a flow rate of 1 ml/h, with the needle tip-to-collector distance at 11 cm (position a, and the applied voltage of 18 kV. This combination was further validated by conducting a confirmation experiment that used two different needles to study the effect of needle size. The average nanofiber diameter was approximately the same for both needle sizes in good accordance with the optimum condition estimated by the Taguchi DoE method.

  6. Symbiotic organism search algorithm for simulation of J- V characteristics and optimizing internal parameters of DSSC developed using electrospun TiO2 nanofibers

    Science.gov (United States)

    Vinoth, S.; Kanimozhi, G.; Kumar, Harish; Srinadhu, E. S.; Satyanarayana, N.

    2017-12-01

    In the present investigation, the recently developed, simple, robust, and powerful metaheuristic symbiotic organism search (SOS) algorithm was used for simulation of J- V characteristics and optimizing the internal parameters of the dye-sensitized solar cells (DSSCs) fabricated using electrospun 1-D mesoporous TiO2 nanofibers as photoanode. The efficiency ( η = 5.80 %) of the DSSC made up of TiO2 nanofibers as photoanode is found to be ˜ 21.59% higher compared to the efficiency ( η = 4.77 %) of the DSSC made up of TiO2 nanoparticles as photoanode. The observed high efficiency can be attributed to high dye loading as well as high electron transport in the mesoporous 1-D TiO2 nanofibers. Further, the validity and advantage of SOS algorithm are verified by simulating J- V characteristics of DSSC with Lambert-W function.

  7. Electrospun TiO2/C Nanofibers As a High-Capacity and Cycle-Stable Anode for Sodium-Ion Batteries.

    Science.gov (United States)

    Xiong, Ya; Qian, Jiangfeng; Cao, Yuliang; Ai, Xinping; Yang, Hanxi

    2016-07-06

    Nanosized TiO2 is now actively developed as a low-cost and potentially high capacity anode material of Na-ion batteries, but its poor capacity utilization and insufficient cyclability remains an obstacle for battery applications. To overcome these drawbacks, we synthesized electrospun TiO2/C nanofibers, where anatase TiO2 nanocrystals with a diameter of ∼12 nm were densely embedded in the conductive carbon fibers, thus preventing them from aggregating and attacking by electrolyte. Due to its abundant active surfaces of well-dispersed TiO2 nanocrytals and high electronic conductivity of the carbon matrix, the TiO2/C anode shows a high redox capacity of ∼302.4 mA h g(-1) and a high-rate capability of 164.9 mAh g(-1) at a very high current of 2000 mA g(-1). More significantly, this TiO2/C anode can be cycled with nearly 100% capacity retention over 1000 cycles, showing a sufficiently long cycle life for battery applications. The nanofibrous architecture of the TiO2/C composite and its superior electrochemical performance may provide new insights for development of better host materials for practical Na-ion batteries.

  8. Electrospun cerium-based TiO2 nanofibers for photocatalytic oxidation of elemental mercury in coal combustion flue gas.

    Science.gov (United States)

    Wang, Lulu; Zhao, Yongchun; Zhang, Junying

    2017-10-01

    Photocatalytic oxidation is an attractive method for Hg-rich flue gas treatment. In the present study, a novel cerium-based TiO2 nanofibers was prepared and selected as the catalyst to remove mercury in flue gas. Accordingly, physical/chemical properties of those nanofibers were clarified. The effects of some important parameters, such as calcination temperature, cerium dopant content and different illumination conditions on the removal of Hg(0) using the photocatalysis process were investigated. In addition, the removal mechanism of Hg(0) over cerium-based TiO2 nanofibers focused on UV irradiation was proposed. The results show that catalyst which was calcined at 400 °C exhibited better performance. The addition of 0.3 wt% Ce into TiO2 led to the highest removal efficiency at 91% under UV irradiation. As-prepared samples showed promising stability for long-term use in the test. However, the photoluminescence intensity of nanofibers incorporating ceria was significantly lower than TiO2, which was attributed to better photoelectron-hole separation. Although UV and O2 are essential factors, the enhancement of Hg(0) removal is more obviously related to the participation of catalyst. The coexistence of Ce(3+) and Ce(4+), which leads to the efficient oxidation of Hg(0), was detected on samples. Hg(2+) is the final product in the reaction of Hg(0) removal. As a consequence, the emissions of Hg(0) from flue gas can be significantly suppressed. These indicate that combining photocatalysis technology with cerium-based TiO2 nanofibers is a promising strategy for reducing Hg(0) efficiently. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Fabrication and characterization of electrospun titania nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Chandrasekar, Ramya [South Dakota School of Mines and Technology; Zhang, Lifeng [ORNL; Howe, Jane Y [ORNL; Hedin, Nyle E [Department of Chemistry, South Dakota School of Mines; Zhang, Y [School of Physics and Materials Science, Anhui University, Hefei, Anhui 230039, China

    2009-01-01

    Titania (TiO2) nanofibers were fabricated by electrospinning three representative spin dopes made of titanium (IV) n-butoxide (TNBT) and polyvinylpyrrolidone (PVP) with the TNBT/PVP mass ratio being 1/2 in three solvent systems including N,N-dimethylformamide (DMF), isopropanol, and DMF/isopropanol (1/1 mass ratio) mixture, followed by pyrolysis at 500 C. The detailed morphological and structural properties of both the as-electrospun precursor nanofibers and the resulting final TiO2 nanofibers were characterized by SEM, TEM, and XRD. The results indicated that the precursor nanofibers and the final TiO2 nanofibers made from the spin dopes containing DMF alone or DMF/isopropanol mixture as the solvent had the common cylindrical morphology with diameters ranging from tens to hundreds of nanometers, while those made from the spin dope containing isopropanol alone as the solvent had an abnormal concave morphology with sizes/widths ranging from sub-microns to microns. Despite the morphological discrepancies, all precursor nanofibers were structurally amorphous without distinguishable phase separation, while all final TiO2 nanofibers consisted of anatase-phased TiO2 single-crystalline grains with sizes of approximately 10 nm. The electrospun TiO2 nanofiber mat is expected to significantly outperform other forms (such as powder and film) of TiO2 for the solar cell (particularly dye-sensitized solar cell) and photo-catalysis applications.

  10. Modelling studies for photocatalytic degradation of organic dyes using TiO2nanofibers.

    Science.gov (United States)

    Singh, Narendra; Rana, Mohit Singh; Gupta, Raju Kumar

    2017-09-05

    In this work, modelling of the photocatalytic degradation of para-nitrophenol (PNP) using synthesized electrospun TiO 2 nanofibers under UV light illumination is reported. A dynamic model was developed in order to understand the behaviour of operating parameters, i.e. light intensity and catalyst loading on the photocatalytic activity. This model was simulated and analysed for both TiO 2 solid nanofibers and TiO 2 hollow nanofibers, applied as photocatalysts in the Langmuir-Hinshelwood kinetic framework. The entire photocatalytic degradation rate follows pseudo-first-order kinetics. The simulated results obtained from the developed model are in good agreement with the experimental results. At a catalyst loading of 1.0 mg mL -1 , better respective degradation rates were achieved at UV light irradiance of 4 mW cm -2 , for both the TiO 2 solid and hollow nanofibers. However, it was also observed that TiO 2 hollow nanofibers have a higher adsorption rate than that of TiO 2 solid nanofibers resulting in a higher photocatalytic degradation rate of PNP.

  11. Electrospun Nanofibers for Regenerative Medicine**

    OpenAIRE

    Liu, Wenying; Thomopoulos, Stavros; Xia, Younan

    2011-01-01

    This article reviews recent progress in applying electrospun nanofibers to the emerging field of regenerative medicine. We begin with a brief introduction to electrospinning and nanofibers, with a focus on issues related to the selection of materials, incorporation of bioactive molecules, degradation characteristics, control of mechanical properties, and facilitation of cell infiltration. We then discuss a number of approaches to fabrication of scaffolds from electrospun nanofibers, including...

  12. Electrospun Nanofibers Applications in Dentistry

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    Seog-Jin Seo

    2016-01-01

    Full Text Available Nanofibrous structures exhibit many interesting features, such as high surface area and surface functionalization and porosity in the range from submicron to nanoscale, which mimics the natural extracellular matrix. In particular, electrospun nanofibers have gained great attention in the field of tissue engineering due to the ease of fabrication and tailorability in pore size, scaffold shape, and fiber alignment. For the reasons, recently, polymeric nanofibers or bioceramic nanoparticle-incorporated nanofibers have been used in dentistry, and their nanostructure and flexibility have contributed to highly promotive cell homing behaviors, resulting in expecting improved dental regeneration. Here, this paper focuses on recently applied electrospun nanofibers in dentistry in the range from the process to the applications.

  13. Ammonia Sensing Behaviors of TiO2-PANI/PA6 Composite Nanofibers

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    Fenglin Huang

    2012-12-01

    Full Text Available Titanium dioxide-polyaniline/polyamide 6 (TiO2-PANI/PA6 composite nanofibers were prepared by in situ polymerization of aniline in the presence of PA6 nanofibers and a sputtering-deposition process with a high purity titanium sputtering target. TiO2-PANI/PA6 composite nanofibers and PANI/PA6 composite nanofibers were fabricated for ammonia gas sensing. The ammonia sensing behaviors of the sensors were examined at room temperature. All the results indicated that the ammonia sensing property of TiO2-PANI/PA6 composite nanofibers was superior to that of PANI/PA6 composite nanofibers. TiO2-PANI/PA6 composite nanofibers had good selectivity to ammonia. It was also found that the content of TiO2 had a great influence on both the morphology and the sensing property of TiO2-PANI/PA6 composite nanofibers.

  14. Ammonia sensing behaviors of TiO2-PANI/PA6 composite nanofibers.

    Science.gov (United States)

    Wang, Qingqing; Dong, Xianjun; Pang, Zengyuan; Du, Yuanzhi; Xia, Xin; Wei, Qufu; Huang, Fenglin

    2012-12-12

    Titanium dioxide-polyaniline/polyamide 6 (TiO(2)-PANI/PA6) composite nanofibers were prepared by in situ polymerization of aniline in the presence of PA6 nanofibers and a sputtering-deposition process with a high purity titanium sputtering target. TiO(2)-PANI/PA6 composite nanofibers and PANI/PA6 composite nanofibers were fabricated for ammonia gas sensing. The ammonia sensing behaviors of the sensors were examined at room temperature. All the results indicated that the ammonia sensing property of TiO(2)-PANI/PA6 composite nanofibers was superior to that of PANI/PA6 composite nanofibers. TiO(2)-PANI/PA6 composite nanofibers had good selectivity to ammonia. It was also found that the content of TiO(2) had a great influence on both the morphology and the sensing property of TiO(2)-PANI/PA6 composite nanofibers.

  15. Penggunaan Katalis Komposit Terimmobilisasi Berbasis Nanofiber Tio2 Dalam Pengolahan Fotokatalitik Limbah Cair Berwarna Tekstil

    OpenAIRE

    Doni, Sugiyana; Suprihanto, Notodarmojo

    2012-01-01

    Dalam penelitian ini telah dilakukan evaluasi penggunaan material katalis komposit terimmobilisasi berbasis nanofiber TiO2 untuk pengolahan fotokatalitik limbah cair berwarna tekstil. Sintesis nanofiber TiO2 dilakukan dengan menggunakan metoda electrospinning, diimmobilisasikan pada media pelat gelas kemudian dikalsinasi pada temperatur 500oC. Komposit nanofiber – nanopartikel dibuat dengan melekatkan nanopartikel TiO2 pada permukaan katalis nanofiber. Perlekatan lapisan katalis komposit pada...

  16. Synthesis and Characterization of Electrospun Nanocomposite TiO Nanofibers with Ag Nanoparticles for Photocatalysis Applications

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    Srujan Mishra

    2012-01-01

    Full Text Available Polycrystalline mixed-phase TiO2 nanofibers embedded with 2.0% w/v Ag nanoparticles was prepared by the electrospinning technique. Calcination of dry Ag nanoparticles-titanium (IV isopropoxide/PVP electrospun nanofiber mats in air at 510∘C for 24 h yielded polycrystalline TiO2/Ag nanofibers. The morphology and distribution of silver nanoparticles were observed by transmission electron microscopy (TEM, scanning TEM (STEM, and high-angle annular dark-field (HAADF imaging. Mixed-phase anatase and rutile TiO2 nanofibers were produced with Ag nanoparticles. High-resolution TEM lattice-fringe measurements showed good agreement with Ag (111, anatase (101, and rutile (110 phases. The photocatalytic activity of TiO2/Ag nanofibers was compared to the photocatalytic activity of pure TiO2 nanofibers by studying the photodegradation of methyl red dye under UV light irradiation, in a photoreactor. UV-visible absorbance spectra showed that the rate of decay of the dye in case of photodegradation by TiO2/Ag nanofibers was 10.3 times higher than that by pure TiO2 nanofibers. The retaining of the fiber morphology along with the increased surface area due to the addition of Ag nanoparticles can be believed to enhance the photocatalytic oxidation of methyl red dye.

  17. Biomimetic electrospun nanofibers for tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Susan; Li Bojun; Ma Zuwei; Wei He; Chan Casey; Ramakrishna, Seeram [Nanoscience and Nanotechnology Initiative (NUSNNI), Faculty of Engineering, National University of Singapore, 117576 Singapore (Singapore)

    2006-09-15

    Nanofibers exist widely in human tissue with different patterns. Electrospinning nanotechnology has recently gained a new impetus due to the introduction of the concept of biomimetic nanofibers for tissue regeneration. The advanced electrospinning technique is a promising method to fabricate a controllable continuous nanofiber scaffold similar to the natural extracellular matrix. Thus, the biomedical field has become a significant possible application field of electrospun fibers. Although electrospinning has developed rapidly over the past few years, electrospun nanofibers are still at a premature research stage. Further comprehensive and deep studies on electrospun nanofibers are essential for promoting their biomedical applications. Current electrospun fiber materials include natural polymers, synthetic polymers and inorganic substances. This review briefly describes several typically electrospun nanofiber materials or composites that have great potential for tissue regeneration, and describes their fabrication, advantages, drawbacks and future prospects. (topical review)

  18. Electrospinning Preparation and Photocatalytic Activity of Porous TiO2 Nanofibers

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    Shanhu Liu

    2012-01-01

    Full Text Available Porous TiO2 nanofibers were prepared via a facile electrospinning method. The carbon nanospheres were mixed with the ethanol solution containing both poly(vinylpyrrolidone and titanium tetraisopropoxide for electrospinning; and subsequent calcination of as-spun nanofibers led to thermal decomposition of carbon nanospheres, leaving behind pores in the TiO2 nanofibers. The morphology and phase structure of the products were investigated with scanning electron microscopy (SEM, transmission electron microscopy (TEM, and X-ray diffraction (XRD. Furthermore, the photocatalytic activity of porous TiO2 nanofibers was evaluated by photodecomposition of methylene blue under UV light. Results showed that the porous TiO2 nanofibers have higher surface area and enhanced photocatalysis activity, compared to nonporous TiO2 nanofibers.

  19. The Electrospun Ceramic Hollow Nanofibers

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    Shahin Homaeigohar

    2017-11-01

    Full Text Available Hollow nanofibers are largely gaining interest from the scientific community for diverse applications in the fields of sensing, energy, health, and environment. The main reasons are: their extensive surface area that increases the possibilities of engineering, their larger accessible active area, their porosity, and their sensitivity. In particular, semiconductor ceramic hollow nanofibers show greater space charge modulation depth, higher electronic transport properties, and shorter ion or electron diffusion length (e.g., for an enhanced charging–discharging rate. In this review, we discuss and introduce the latest developments of ceramic hollow nanofiber materials in terms of synthesis approaches. Particularly, electrospinning derivatives will be highlighted. The electrospun ceramic hollow nanofibers will be reviewed with respect to their most widely studied components, i.e., metal oxides. These nanostructures have been mainly suggested for energy and environmental remediation. Despite the various advantages of such one dimensional (1D nanostructures, their fabrication strategies need to be improved to increase their practical use. The domain of nanofabrication is still advancing, and its predictable shortcomings and bottlenecks must be identified and addressed. Inconsistency of the hollow nanostructure with regard to their composition and dimensions could be one of such challenges. Moreover, their poor scalability hinders their wide applicability for commercialization and industrial use.

  20. Electrospun MOF nanofibers as hydrogen storage media

    CSIR Research Space (South Africa)

    Ren, Jianwei

    2015-06-01

    Full Text Available In this study, Zr-MOF and Cr-MOF were chosen as representatives of the developed MOFs in our laboratory and were incorporated into electrospun nanofibers. The obtained MOF nanofibers composites were evaluated as hydrogen storage media. The results...

  1. Templating quantum dot to phase-transformed electrospun TiO₂ nanofibers for enhanced photo-excited electron injection.

    Science.gov (United States)

    Aykut, Yakup; Saquing, Carl D; Pourdeyhimi, Behnam; Parsons, Gregory N; Khan, Saad A

    2012-08-01

    We report on the microstructural crystal phase transformation of electrospun TiO(2) nanofibers generated via sol-gel electrospinning technique, and the incorporation of as-synthesized CdSe quantum dots (QDs) to different phases of TiO(2) nanofibers (NFs) via bifunctional surface modification. The effect of different phases of TiO(2) on photo-excited electron injection from CdSe QDs to TiO(2) NFs, as measured by photoluminescence spectroscopy (PL) is also discussed. Nanofiber diameter and crystal structures are dramatically affected by different calcination temperatures due to removal of polymer carrier, conversion of ceramic precursor into ceramic nanofibers, and formation of different TiO(2) phases in the fibers. At a low calcination temperature of 400 (o)C only anatase TiO(2) nanofiber are obtained; with increasing calcination temperature (up to 500 (o)C) these anatase crystals became larger. Crystal transformation from the anatase to the rutile phase is observed above 500(o)C, with most of the crystals transforming into the rutile phase at 800(o)C. Bi-functional surface modification of calcined TiO(2) nanofibers with 3-mercaptopropionic acid (3-MPA) is used to incorporate as-synthesized CdSe QD nanoparticles on to TiO(2) nanofibers. Evidence of formation of CdSe/TiO(2) composite nanofibers is obtained from elemental analysis using Energy Dispersive X-ray spectroscopy (EDS) and TEM microscopy that reveal templated quantum dots on TiO(2) nanofibers. Photoluminescence emission intensities increase considerably with the addition of QDs to all TiO(2) nanofiber samples, with fibers containing small amount of rutile crystals with anatase crystals showing the most enhanced effect.

  2. Electrospinning Synthesis and Photocatalytic Activity of Mesoporous TiO2 Nanofibers

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    Jing Li

    2012-01-01

    Full Text Available Titanium dioxide (TiO2 nanofibers in the anatase structure were successfully prepared via electrospinning technique followed by calcination process. The morphologies, crystal structure, surface area, and the photocatalytic activity of resulting TiO2 nanofibers were characterized by field emission scanning electron microscopy (FE-SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD, nitrogen sorption, and UV-vis spectroscopy. The results revealed that calcination temperature had greatly influenced the morphologies of TiO2 nanofibers, but no obvious effect was noticed on the crystal structure of TiO2 nanofibers. The photocatalytic properties of TiO2 nanofibers were evaluated by photocatalytic degradation of rhodamine B (RhB in water under visible light irradiation. It was observed that TiO2 nanofibers obtained by calcination at 500°C for 3 hours exhibited the most excellent photocatalytic activity. We present a novel and simple method to fabricate TiO2 nanofibers with high-photocatalytic activity.

  3. Photocatalytic performance of melt-electrospun polypropylene fabric decorated with TiO2 nanoparticles

    Science.gov (United States)

    Karahaliloglu, Zeynep; Hacker, Christoph; Demirbilek, Murat; Seide, Gunnar; Denkbas, Emir Baki; Gries, Thomas

    2014-09-01

    Recently, nanomaterials, especially titanium-based nanomaterials, have a great potential for decolorization of textile dye effluents. In this article, the nanofibrillar filters functionalized with titanium nanoparticle (nTi) were designed to improve dyeing wastewater decolorization. Pristine polypropylene (PP) and nTi-PP nanocomposite nonwovens were produced as a photocatalyzer by melt-electrospinning process. The average diameter of pristine PP- and nTi-PP nanocomposite melt-electrospun fibers was found average as 700 ± 0.3 and 800 ± 0.4 nm, respectively. Before functionalization with nTi, the surface of fabrics was activated by a technique using glutaraldehyde (GA) and polyethyleneimine to improve decomposition activity. Scanning electron microscopy (SEM) results revealed that titanium nanoparticles were deposited uniformly on the nanofibers. X-ray photon spectroscopy (XPS) results confirmed the presence of titanium nanoparticles and generation of amine groups after modification. Photocatalytic performance of nTi-loaded pristine and nanocomposite melt-electrospun filters was investigated by using methyl orange (MO) as a model compound. The decolorization experiments were carried out by varying initial dye concentration (10, 20, 40 mg/L), pH (2, 5, and 9), and loaded TiO2 amount (1 and 2 %). According to photocatalytic decolarization test results, nTi-loaded GA-treated pristine or nTi-PP nanocomposite fabric filter has better properties compared to GA-untreated group from point of photocatalytic efficiency, especially over 90 % decolorization efficiency at GA-treated pristine and nTi-PP composite PP fabrics. The complete decolarization of MO was observed at pH value of 5, photocatalyst concentration of 20 mg/L, and 1 % nTi-loading after 3 h. The results show that surface activated PP nonwovens, which is introduced Ti nanoparticles into and onto the structure, a good photocatalytic activity.

  4. Microwave Assisted Synthesis, Modification With Platinum And Photocatalytical Properties of TiO2 Nanofibers

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    Reinis DRUNKA

    2016-05-01

    Full Text Available In the present work formation of active TiO2 nanoparticles in microwave synthesis and their modification with platinum were studied. Anatase nanopowder and 10 M KOH solution were used as raw materials. Microwave assisted synthesis method permited to obtain TiO2 nanofibres and nanowires with a diameter of 10 nm and a specific surface area in the range of 70 – 150 m2/g. In order to modify TiO2 nanofibers with platinum it was stirred in H2PtCl6 solution under UV irradiation. Photocatalytic activity was determined by degradation of the methylene blue (MB solution under UV and visible light irradiation. The obtained samples showed higher photocatalytic activity with respect to pure TiO2 nanofibers. The doped TiO2 nanofibers were appropriate for degradation of harmful organic compounds as well as for hydrogen production by water splitting.

  5. High Strength and High Modulus Electrospun Nanofibers

    OpenAIRE

    Jian Yao; Cees W. M. Bastiaansen; Ton Peijs

    2014-01-01

    Electrospinning is a rapidly growing polymer processing technology as it provides a viable and simple method to create ultra-fine continuous fibers. This paper presents an in-depth review of the mechanical properties of electrospun fibers and particularly focuses on methodologies to generate high strength and high modulus nanofibers. As such, it aims to provide some guidance to future research activities in the area of high performance electrospun fibers.

  6. Preparation and characterization of TiO2 coated Fe nanofibers for electromagnetic wave absorber.

    Science.gov (United States)

    Jang, Dae-Hwan; Song, Hanbok; Lee, Young-In; Lee, Kun-Jae; Kim, Ki Hyeon; Oh, Sung-Tag; Lee, Sang-Kwan; Choa, Yong-Ho

    2011-01-01

    Recently, electromagnetic interference (EMI) and electromagnetic compatibility (EMC) have become serious problems due to the growth of electronic device and next generation telecommunication. It is necessary to develop new electromagnetic wave absorbing material to overcome the limitation of electromagnetic wave shielding materials. The EMI attenuation is normally related to magnetic loss and dielectric loss. Therefore, magnetic material coating dielectric materials are required in this reason. In this study, TiO2 coated Fe nanofibers were prepared to improve their properties for electromagnetic wave absorption. Poly(vinylpyrrolidone) (PVP) and Iron (III) nitrate nonahydrate (Fe(NO3)3 x 9H2O) were used as starting materials for the synthesis of Fe oxide nanofibers. Fe oxide nanofibers were prepared by electrospinning in an electric field and heat treatment. TiO2 layer was coated on the surface of Fe oxide nanofibers using sol-gel process. After the reduction of TiO2 coated Fe oxide nanofibers, Fe nanofibers with a TiO2 coating layer of about 10 nm were successfully obtained. The morphology and structure of fibers were characterized by SEM, TEM, and XRD. In addition, the absorption properties of TiO2 coated Fe nanofibers were measured by network analyzer.

  7. Synthesis and Characterization of Stable and Binder-Free Electrodes of TiO2 Nanofibers for Li-Ion Batteries

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    Phontip Tammawat

    2013-01-01

    Full Text Available An electrospinning technique was used to fabricate TiO2 nanofibers for use as binder-free electrodes for lithium-ion batteries. The as-electrospun nanofibers were calcined at 400–1,000°C and characterized using X-ray diffraction (XRD, scanning electron microscopy (SEM, and transmission electron microscopy (TEM. SEM and TEM images showed that the fibers have an average diameter of ~100 nm and are composed of nanocrystallites and grains, which grow in size as the calcination temperature increases. The electrochemical properties of the nanofibers were evaluated using galvanostatic cycling and electrochemical impedance spectroscopy. The TiO2 nanofibers calcined at 400°C showed higher electronic conductivity, higher discharge capacity, and better cycling performance than the nanofibers calcined at 600, 800, and 1,000°C. The TiO2 nanofibers calcined at 400°C delivered an initial reversible capacity of 325 mAh·g−1 approaching their theoretical value at 0.1 C rate and over 175 mAh·g−1 at 0.3 C rate with limited capacity fading and Coulombic efficiency between 96 and 100%.

  8. Fabrication of doped Titania (TiO2) nano-catalysts in the shape of nanofibers

    DEFF Research Database (Denmark)

    Marani, Debora; Silva, Rafael Hubert; Zhang, Wenjing (Angela)

    -catalysts for the removal of the NOx in exhausts via the NH3 Selective Catalytic Reduction method (SCR). The state-of-art system WO3-V2O5 was incorporated into TiO2 ceramic nanofibers through combination of electrospinning and sol-gel process. Catalytic functionalized nanofibers were characterized using SEM, TEM, EDX, BET...

  9. Electrospun nanofibers for energy and environmental applications

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Bin; Yu, Jianyong (eds.) [Donghua Univ., Shanghai (China). State Key Lab. for Modification of Chemical Fibers and Polymer Materials; Donghua Univ., Shanghai (China). Nanomaterials Research Center

    2014-10-01

    This book offers a comprehensive review of the latest advances in developing functional electrospun nanofibers for energy and environmental applications, which include fuel cells, lithium-ion batteries, solar cells, supercapacitors, energy storage materials, sensors, filtration materials, protective clothing, catalysis, structurally-colored fibers, oil spill cleanup, self-cleaning materials, adsorbents, and electromagnetic shielding.

  10. A minitablet formulation made from electrospun nanofibers.

    Science.gov (United States)

    Poller, Bettina; Strachan, Clare; Broadbent, Roland; Walker, Greg F

    2017-05-01

    The purpose of this study was to evaluate electrospun drug loaded nanofibers as a new matrix for minitablets. Prednisone, a poorly water-soluble drug, was loaded into povidone (polyvinylpyrrolidone, PVP) nanofibers using the process of electrospinning. The drug-loaded nanofiber mat was compressed into minitablets with a 2mm diameter and a height of 2.63±0.04mm. SEM analysis of the minitablet identified a nano-web structure with a nanofiber diameter in the range of 400-500nm. The minitablets met the requirements of the US Pharmacopeia with respect to content uniformity and friability. DSC and XRPD analysis of the minitablet indicated that the drug-polymer mixture was a one-phase amorphous system. XRPD analysis of the drug loaded nanofiber mat after 10-months of storage at ambient temperature showed no evidence of recrystallization of the drug. Solubility and dissolution properties of the drug formulated into a nanofiber mat and minitablet were evaluated. These results show that electrospun nanofibers may provide a useful matrix for the further development of minitablets. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. A review on electrospun nanofibers for oral drug delivery

    National Research Council Canada - National Science Library

    Abbas Akhgari; Zahra Shakib; Setareh Sanati

    2017-01-01

    .... Due to these properties electrospun nanofibers have been extensively used for different biomedical applications including wound dressing, tissue engineering, enzyme immobilization, artificial organs, and drug delivery...

  12. Potential of Electrospun Nanofibers for Biomedical and Dental Applications

    National Research Council Canada - National Science Library

    Muhammad Zafar; Shariq Najeeb; Zohaib Khurshid; Masoud Vazirzadeh; Sana Zohaib; Bilal Najeeb; Farshid Sefat

    2016-01-01

    .... Extensive research has been conducted to explore the potential of electrospun nanofibers for repair and regeneration of various dental and oral tissues including dental pulp, dentin, periodontal...

  13. Recent Advances in Electrospun Nanofiber Interfaces for Biosensing Devices

    National Research Council Canada - National Science Library

    Eleni Sapountzi; Mohamed Braiek; Jean-François Chateaux; Nicole Jaffrezic-Renault; Florence Lagarde

    2017-01-01

    .... Electrospun nanofibers have demonstrated high potential for a wide spectrum of applications, including drug delivery, tissue engineering, energy conversion and storage, or physical and chemical sensors...

  14. Hybrid matrices of TiO2 and TiO2–Ag nanofibers with silicone for high water flux photocatalytic degradation of dairy effluent

    DEFF Research Database (Denmark)

    Kanjwal, Muzafar Ahmad; Alm, Martin; Thomsen, Peter

    2016-01-01

    TiO2 and TiO2–Ag nanofibers were produced by electrospinning technique and surface coated on silicone elastomer (diameter: 10.0 mm; thickness: 2.0 mm) by dipcoating method. These coated hybrid nanoporous matrices were characterized by various morphological and physicochemical techniques (like SEM...

  15. Preparation and characterization of kefiran electrospun nanofibers.

    Science.gov (United States)

    Esnaashari, Seyedeh Sara; Rezaei, Sasan; Mirzaei, Esmaeil; Afshari, Hamed; Rezayat, Seyed Mahdi; Faridi-Majidi, Reza

    2014-09-01

    In this study, we report the first successful production of kefiran nanofibers through electrospinning process using distilled water as solvent. For this purpose, kefiran was extracted from cultured kefir grains, and homogenous kefiran solutions with different concentrations were prepared and then electrospun to obtain uniform nanofibers. The effect of main process parameters, including applied voltage, tip-to-collector distance, and feeding rate, on diameter and morphology of produced nanofibers, was studied. Scanning electron microscopy (SEM) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy were used to characterize electrospun mats. Rheological behavior of the kefiran solution was evaluated via a cone and plate rheometer too. The results exhibited that diameter of kefiran nanofibers increased with increasing polymer concentration, applied voltage, and polymer feeding rate, while tip-to-collector distance did not have significant effect on nanofiber diameter. ATR-FTIR spectra showed that kefiran has maintained its molecular structure during electrospinning process. Flow curves also demonstrated shear thinning behavior for kefiran solutions. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Hierarchical assembly of BiOCl nanosheets onto bicrystalline TiO2 nanofiber: enhanced photocatalytic activity based on photoinduced interfacial charge transfer.

    Science.gov (United States)

    Li, Lu; Zhang, Mingyi; Liu, Ying; Zhang, Xitian

    2014-12-01

    One-dimensional ternary hierarchical heterostructures based on BiOCl nanosheets and bicrystalline TiO2 nanofiber frameworks that consist of anatase-rutile (AR) mixed phase TiO2 nanoparticles were successfully designed by combining the electrospinning technique and solvothermal method. The BiOCl nanosheets were uniformly grown onto the electrospun TiO2 nanofibers, and the density of the secondary BiOCl nanosheets could be controlled by adjusting the precursor concentration. Photocatalytic tests displayed that the ternary BiOCl/TiO2 (AR) hierarchical heterostructures possessed a much higher degradation rate than the bare bicrystalline TiO2 (AR) nanofibers, BiOCl/TiO2 (A) or BiOCl/TiO2 (R) composite. It is mainly attributed to the photogenerated interfacial charge transfer based on the photosynergistic effect of the heterojunctions, which results in the high separation efficiency of photogenerated electron-hole pairs. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Electrospun nanofibers in energy and environmental applications

    Energy Technology Data Exchange (ETDEWEB)

    Thavasi, V.; Singh, G.; Ramakrishna, S.

    2008-07-01

    Nanotechnology is providing new solutions and opportunities to ensure sustainable energy and environments for the future. Materials of nanofiberous morphology are attractive to solve numerous energy and environmental issues. Nanofibers can be effectively produced by electrospinning, which is a simple and low cost technique. In addition, electrospinning allows the production of nanofibers from various materials e.g. organics and inorganics in different configurations and assemblies. This is highly beneficial for energy devices, where inorganic materials especially metal oxides can be synthesized and electrospun, improving conducting and ceramic properties. Excitonic solar cells fabricated with aligned nanofiberous metal oxide electrodes provide higher solar-electric energy conversion efficiency, whereas fuel cells made with nanofiberous electrodes enable uniform dispersion of catalysts, and thus increase electrocatalytic activity to obtain higher chemical-electric energy conversion efficiency. The nanofibers used in filtration membranes for environmental remediation, minimize the pressure drop and provide better efficiency than conventional fiber mats. The large surface area-to-volume ratio of nanofiber membranes allows greater surface adsorption of contaminants from air and water, and increases the life-time of the filtration media. This review highlights the potential and application of electrospun nanofiberous materials for solving critical energy and environmental issues. (GB)

  18. Conductivity dependence of lithium diffusivity and electrochemical performance for electrospun TiO2 fibers

    Science.gov (United States)

    Qing, Rui; Liu, Li; Bohling, Christian; Sigmund, Wolfgang

    2015-01-01

    TiO2 is one of the most exciting anode candidates for safe application in lithium ion batteries. However, its low intrinsic electronic conductivity limits application. In this paper, a simple sol-gel based route is presented to produce nanosize TiO2 fibers with 119 ± 27 nm diameters via electrospinning. Subsequent calcination in various atmospheres was applied to achieve anatase and anatase-rutile mixed phase crystallites with and without carbon coating. The crystallite size was 5 nm for argon calcined fibers and 13-20 nm for air calcined fibers. Argon calcined TiO2 nanofibers exhibited electronic conductivity orders of magnitude higher than those of air-calcined samples. Lithium diffusivity was increased by one time and specific capacity by 26.9% due to the enhanced conductivity. It also had a different intercalation mechanism of lithium. Hydrogen post heat-treatment was found to benefit electronic conductivity (by 3-4.5 times), lithium diffusivity (1.5-2 times) and consequently the high rate performance of the TiO2 nanofibers (over 80%). The inner mechanism and structure-property relations among these parameters were also discussed.

  19. Electrospun Nanofibers: Solving Global Issues

    Science.gov (United States)

    Si, Yang; Tang, Xiaomin; Yu, Jianyong; Ding, Bin

    Energy and environment will head the list of top global issues facing society for the next 50 years. Nanotechnology is responding to these challenges by designing and fabricating functional nanofibers optimized for energy and environmental applications. The route toward these nano-objects is based primarily on electrospinning: a highly versatile method that allows the fabrication of continuous fibers with diameters down to a few nanometers. The mechanism responsible for the fiber formation mainly includes the Taylor Cone theory and flight-instability theory, which can be predicted theoretically and controlled experimentally. Moreover, the electrospinning has been applied to natural polymers, synthetic polymers, ceramics, and carbon. Fibers with complex architectures, such as ribbon fiber, porous fiber, core-shell fiber, or hollow fiber, can be produced by special electrospinning methods. It is also possible to produce nanofibrous membranes with designed aggregate structure including alignment, patterning, and two-dimensional nanonets. Finally, the brief analysis of nanofibers used for advanced energy and environmental applications in the past decade indicates that their impact has been realized well and is encouraging, and will continually represent a key technology to ensure sustainable energy and preserve our environment for the future.

  20. Drop impacts on electrospun nanofiber membranes

    Science.gov (United States)

    Sahu, Rakesh P.; Sinha-Ray, Suman; Yarin, Alexander; Pourdeyhimi, Behnam

    2013-11-01

    This work reports a study of drop impacts of polar and non-polar liquids onto electrospun nanofiber membranes (of 8-10 mm thickness and pore sizes of 3-6 nm) with an increasing degree of hydrophobicity. The nanofibers used were electrospun from polyacrylonitrile (PAN), nylon 6/6, polycaprolactone (PCL) and Teflon. It was found that for any liquid/fiber pair there exists a threshold impact velocity (1.5 to 3 m/s) above which water penetrates membranes irrespective of their wettability. The low surface tension liquid left the rear side of sufficiently thin membranes as a millipede-like system of tiny jets protruding through a number of pores. For such a high surface tension liquid as water, jets immediately merged into a single bigger jet, which formed secondary drops due to capillary instability. An especially non-trivial result is that superhydrophobicity of the porous nano-textured Teflon skeleton with the interconnected pores is incapable of preventing water penetration due to drop impact, even at relatively low impact velocities close to 3.46 m/s. A theoretical estimate of the critical membrane thickness sufficient for complete viscous dissipation of the kinetic energy of penetrating liquid corroborates with the experimental data. The current work is supported by the Nonwovens Cooperative Research Center (NCRC).

  1. Electrospun nanofibers as versatile interfaces for efficient gene delivery

    National Research Council Canada - National Science Library

    Lee, Slgirim; Jin, Gyuhyung; Jang, Jae-Hyung

    2014-01-01

    The integration of gene delivery technologies with electrospun nanofibers is a versatile strategy to increase the potential of gene therapy as a key platform technology that can be readily utilized...

  2. Electrospun nanofibers as versatile interfaces for efficient gene delivery

    OpenAIRE

    Lee, Slgirim; Jin, Gyuhyung; Jang, Jae-Hyung

    2014-01-01

    The integration of gene delivery technologies with electrospun nanofibers is a versatile strategy to increase the potential of gene therapy as a key platform technology that can be readily utilized for numerous biomedical applications, including cancer therapy, stem cell therapy, and tissue engineering. As a spatial template for gene delivery, electrospun nanofibers possess highly advantageous characteristics, such as their ease of production, their ECM-analogue nature, the broad range of cho...

  3. Recent Advances in Electrospun Nanofiber Interfaces for Biosensing Devices

    OpenAIRE

    Sapountzi, Eleni; Braiek, Mohamed; Chateaux, Jean-Fran?ois; Jaffrezic-Renault, Nicole; Lagarde, Florence

    2017-01-01

    Electrospinning has emerged as a very powerful method combining efficiency, versatility and low cost to elaborate scalable ordered and complex nanofibrous assemblies from a rich variety of polymers. Electrospun nanofibers have demonstrated high potential for a wide spectrum of applications, including drug delivery, tissue engineering, energy conversion and storage, or physical and chemical sensors. The number of works related to biosensing devices integrating electrospun nanofibers has also i...

  4. Growth and characterization of hydroxyapatite nanorice on TiO2 nanofibers

    KAUST Repository

    Chetibi, Loubna

    2014-04-01

    Hydroxyapatite (HA) coating with nanoparticles like nanorice is fabricated on chemically pretreated titanium (Ti) surface, through an electrochemical deposition approach, for biomaterial applications. The Ti surface was chemically patterned with anatase TiO2 nanofibers. These nanofibers were prepared by in situ oxidation of Ti foils in a concentrated solution of H 2O2 and NaOH, followed by proton exchange and calcinations. Afterward, TiO2 nanofibers on Ti substrate were coated with HA nanoparticles like nanorice. The obtained samples were annealed at high temperature to produce inter diffusion between TiO2 and HA layers. The resultant layers were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), X-ray Diffraction (XRD), Infrared Spectroscopy (FTIR), corrosion tests in SBF solution, and Electron Probe Micro Analysis (EPMA). It was found that only Ti from the titanium substrate diffuses into the HA coating and a good corrosion resistance in simulated body fluid was obtained. © 2014 Elsevier B.V. All rights reserved.

  5. Fabrication of a Highly Sensitive Single Aligned TiO2 and Gold Nanoparticle Embedded TiO2 Nano-Fiber Gas Sensor.

    Science.gov (United States)

    Nikfarjam, Alireza; Hosseini, Seyedsina; Salehifar, Nahideh

    2017-05-10

    In this research, a single-aligned nanofiber of pure TiO2 and gold nanoparticle (GNP)-TiO2 were fabricated using a novel electro-spinning procedure equipped with secondary electrostatic fields on highly sharp triangular and rectangular electrodes provided for gas sensing applications. The sol used for spinning nanofiber consisted of titanium tetraisopropoxide (C12H28O4Ti), acetic acid (CH3COOH), ethanol (C2H5OH), polyvinylpyrrolidone (PVP), and gold nanoparticle solution. FE-SEM, TEM, and XRD were used to characterize the single nanofiber. In triangular electrodes, the electrostatic voltage for aligning single nanofiber between electrodes depends on the angle tip of the electrode, which was around 1.4-2.1, 2-2.9, and 3.2-4.1 kV for 30°, 45°, and 60°, respectively. However, by changing the shape of the electrodes to rectangular samples and by increasing distance between electrodes from 100 to 200 μm, electro-spinning applied voltage decreased. Response of pure TiO2 single nanofiber sensor was measured for 30-200 ppb carbon monoxide gas. The triangular sample revealed better response and lower threshold than the rectangular sample. Adding appropriate amounts of GNP decreased the operating temperature and increased the responses. CO concentration threshold for the pure TiO2 and GNP-TiO2 triangular samples was about 5 ppb and 700 ppt, respectively.

  6. Hybrid electrospun chitosan-phospholipids nanofibers for transdermal drug delivery

    DEFF Research Database (Denmark)

    Mendes, Ana Carina Loureiro; Gorzelanny, Christian; Halter, Natalia

    2016-01-01

    Chitosan (Ch) polysaccharide was mixed with phospholipids (P) to generate electrospun hybrid nanofibers intended to be used as platforms for transdermal drug delivery. Ch/P nanofibers exibithed average diameters ranging from 248 +/- 94 nm to 600 +/- 201 nm, depending on the amount of phospholipid...... culture plate (control). The release of curcumin, diclofenac and vitamin B12, as model drugs, from Ch/P hybrid nanofibers was investigated, demonstrating their potential utilization as a transdermal drug delivery system....

  7. A review on electrospun nanofibers for oral drug delivery

    Directory of Open Access Journals (Sweden)

    Abbas Akhgari

    2017-10-01

    Full Text Available Nowadays, polymer nanofibers have gained attention due to remarkable characteristics such as high porosity and large surface area to volume ratio. Among their fabrication methods, electrospinning technique has been attracted as a simple and reproducible approach. It is a versatile, simple and cost-effective technique for the production of continuous nanofibers with acceptable characteristics such as high porosity, high surface area to volume ratio, high loading capacity and encapsulation efficiency, delivery of multiple drugs, and enhancement of drug solubility. Due to these properties electrospun nanofibers have been extensively used for different biomedical applications including wound dressing, tissue engineering, enzyme immobilization, artificial organs, and drug delivery. Different synthetic and natural polymers have been successfully electrospun into ultrafine fibers. Using electrospun nanofibers as vehicles for oral drug delivery has been investigated in different release manners- fast, biphasic or sustained release. This article presents a review on application of electrospinning technique in oral drug delivery.

  8. Application of direct tracking method for measuring electrospun nanofiber diameter

    Directory of Open Access Journals (Sweden)

    M. Ziabari

    2009-03-01

    Full Text Available In this paper, direct tracking method as an image analysis based technique for measuring electrospun nanofiber diameter has been presented and compared with distance transform method. Samples with known characteristics generated using a simulation scheme known as µ-randomness were employed to evaluate the accuracy of the method. Electrospun webs of polyvinyl alcohol (PVA were also used to verify the applicability of the method on real samples. Since direct tracking as well as distance transform require binary input images, micrographs of the electrospun webs obtained from Scanning Electron Microscopy (SEM were first converted to black and white using local thresholding. Direct tracking resulted in more accurate estimations of fiber diameter for simulated images as well as electrospun webs suggesting the usefulness of the method for electrospun nanofiber diameter measurement.

  9. Carbon Nanotubes in TiO2 Nanofiber Photoelectrodes for High-Performance Perovskite Solar Cells.

    Science.gov (United States)

    Batmunkh, Munkhbayar; Macdonald, Thomas J; Shearer, Cameron J; Bat-Erdene, Munkhjargal; Wang, Yun; Biggs, Mark J; Parkin, Ivan P; Nann, Thomas; Shapter, Joseph G

    2017-04-01

    1D semiconducting oxides are unique structures that have been widely used for photovoltaic (PV) devices due to their capability to provide a direct pathway for charge transport. In addition, carbon nanotubes (CNTs) have played multifunctional roles in a range of PV cells because of their fascinating properties. Herein, the influence of CNTs on the PV performance of 1D titanium dioxide nanofiber (TiO2 NF) photoelectrode perovskite solar cells (PSCs) is systematically explored. Among the different types of CNTs, single-walled CNTs (SWCNTs) incorporated in the TiO2 NF photoelectrode PSCs show a significant enhancement (≈40%) in the power conversion efficiency (PCE) as compared to control cells. SWCNTs incorporated in TiO2 NFs provide a fast electron transfer within the photoelectrode, resulting in an increase in the short-circuit current (Jsc) value. On the basis of our theoretical calculations, the improved open-circuit voltage (Voc) of the cells can be attributed to a shift in energy level of the photoelectrodes after the introduction of SWCNTs. Furthermore, it is found that the incorporation of SWCNTs into TiO2 NFs reduces the hysteresis effect and improves the stability of the PSC devices. In this study, the best performing PSC device constructed with SWCNT structures achieves a PCE of 14.03%.

  10. Fe doped TiO2 nanofibers on the surface of graphene sheets for photovoltaics applications

    Science.gov (United States)

    Farhangi, Nasrin; Medina-Gonzalez, Yaocihuatl; Charpentier, Paul A.

    2011-08-01

    Highly ordered, visible light driven TiO2 nanowire arrays doped with Fe photocatalysts were grown on the surface of functionalized graphene sheets (FGSs) using a sol-gel method with titanium isopropoxide (TIP) monomer, acetic acid (HAc) as the polycondensation agent and iron chloride in the green solvent, supercritical carbon dioxide (scCO2). The morphology of the synthesized materials was studied by SEM and TEM, which showed uniform formation of Fe doped TiO2 nanofibers on the surface of graphene sheets, which acted as a template for nanowire growth through surface -COOH functionalities. Increasing Fe content in the nanowires did not change the morphology significantly. Optical properties of the synthesized composites were examined by UV spectroscopy which showed a significant reduction in band gap with increasing Fe content, i.e. 2.25 eV at 0.6% Fe. The enhancement of the optical properties of synthesized materials was confirmed by photocurrent measurement. The optimum sample containing 0.6% Fe doped TiO2 on the graphene sheets increased the power conversation efficiency by 6-fold in comparison to TiO2 alone.

  11. A novel electrospun silk fibroin/hydroxyapatite hybrid nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Ming, Jinfa, E-mail: jinfa.ming@gmail.com [National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123 (China); College of Textile and Clothing Engineering, Soochow University, Suzhou 215021 (China); Zuo, Baoqi, E-mail: bqzuo@suda.edu.cn [National Engineering Laboratory for Modern Silk, Soochow University, Suzhou 215123 (China); College of Textile and Clothing Engineering, Soochow University, Suzhou 215021 (China)

    2012-11-15

    A novel electrospinning of silk fibroin/hydroxyapatite hybrid nanofibers with different composition ratios was performed with methanoic acid as a spinning solvent. The silk fibroin/hydroxyapatite hybrids containing up to 30% hydroxyapatite nanoparticles could be electrospun into the continuous fibrous structure. The electrospun silk fibroin/hydroxyapatite hybrid nanofibers showed bigger diameter and wider diameter distribution than pure silk fibroin nanofibers, and the average diameter gradually increased from 95 to 582 nm. At the same time, the secondary structure of silk fibroin/hydroxyapatite nanofibers was characterized by X-ray diffraction, Fourier transform infrared analysis, and DSC measurement. Comparing with the pure silk fibroin nanofibers, the crystal structure of silk fibroin was mainly amorphous structure in the hybrid nanofibers. X-ray diffraction results demonstrated the hydroxyapatite crystalline nature remained as evidenced from the diffraction planes (002), (211), (300), and (202) of the hydroxyapatite crystallites, which was also confirmed by Fourier transform infrared analysis. The thermal behavior of hybrid nanofibers exhibited the endothermic peak of moisture evaporation ranging from 86 to 113 Degree-Sign C, and the degradation peak at 286 Degree-Sign C appeared. The SF/HAp nanofibers mats containing 30% HAp nanoparticles showed higher breaking tenacity and extension at break for 1.1688 {+-} 0.0398 MPa and 6.55 {+-} 1.95%, respectively. Therefore, the electrospun silk fibroin/hydroxyapatite hybrid nanofibers should be provided potentially useful options for the fabrication of biomaterial scaffolds for bone tissue engineering. -- Highlights: Black-Right-Pointing-Pointer The novel SF/HAp nanofibers were directly prepared by electrospinning method. Black-Right-Pointing-Pointer The nanofiber diameter had significant related to the content of HAp. Black-Right-Pointing-Pointer The crystal structure of silk fibroin was mainly amorphous structure in

  12. Fluorescent and Colorimetric Electrospun Nanofibers for Heavy-Metal Sensing

    Directory of Open Access Journals (Sweden)

    Idelma A. A. Terra

    2017-12-01

    Full Text Available The accumulation of heavy metals in the human body and/or in the environment can be highly deleterious for mankind, and currently, considerable efforts have been made to develop reliable and sensitive techniques for their detection. Among the detection methods, chemical sensors appear as a promising technology, with emphasis on systems employing optically active nanofibers. Such nanofibers can be obtained by the electrospinning technique, and further functionalized with optically active chromophores such as dyes, conjugated polymers, carbon-based nanomaterials and nanoparticles, in order to produce fluorescent and colorimetric nanofibers. In this review we survey recent investigations reporting the use of optically active electrospun nanofibers in sensors aiming at the specific detection of heavy metals using colorimetry and fluorescence methods. The examples given in this review article provide sufficient evidence of the potential of optically electrospun nanofibers as a valid approach to fabricate highly selective and sensitive optical sensors for fast and low-cost detection of heavy metals.

  13. Electrospun nanofiber belts made from high performance copolyimide.

    Science.gov (United States)

    Chen, Shuiliang; Hu, Ping; Greiner, Andreas; Cheng, Chuyun; Cheng, Haofang; Chen, Fangfang; Hou, Haoqing

    2008-01-09

    Electrospun nanofibers based on copolyimides were made, aiming at finding a promising method for improving the mechanical properties of electrospun polyimide nanofibers. The copolyimide had a backbone consisting of 3,3',4,4'-biphenyl-tetracarboxylic dianhydride (BPDA), biphenylamide (BPA) and 4,4'-oxydianiline (ODA) residues. The structure and composition of the copolyimide was controlled by the ratio of rigid BPA and flexible ODA moieties. The electrospun copolyimide nanofibers were collected in the form of a belt using a rotating disc with a rim of 8 mm width. Scanning electron microscopy (SEM), infrared (IR) spectroscopy, x-ray scattering and tensile testing, dynamic mechanical analysis (DMA) and thermogravimetric analysis (TGA) were used to characterize the nanofiber belts. The nanofibers had a diameter range from 80 to 300 nm and were well aligned in the belts. The thermal stability of the nanofiber belts was over 460 °C. The tensile test showed that the copolyimide nanofiber belts had much better mechanical properties than either of the flexible and rigid homo-polyimide (homo-PI) nanofiber belts. The tensile strength, modulus and elongation to break of the copolyimide nanofiber belt with BPA/ODA ratio of 40/60 are respectively 1.1 ± 0.1 GPa, 6.2 ± 0.7 GPa and 20.8 ± 1.2%, compared to 459 ± 36 MPa, 2.1 ± 0.3 GPa and 41.3 ± 2.2% for BPDA/ODA homo-PI as well as 384 ± 18 MPa, 11.5 ± 0.6 GPa and 3.9 ± 0.1% for BPDA/BPA homo-PI. The important feature is that the electrospun polymer nanofibers can be made very strong by using copolyimides as spinning materials.

  14. Electrospun Ceramic Nanofiber Mats Today: Synthesis, Properties, and Applications

    Directory of Open Access Journals (Sweden)

    Hamid Esfahani

    2017-10-01

    Full Text Available Ceramic nanofibers (NFs have recently been developed for advanced applications due to their unique properties. In this article, we review developments in electrospun ceramic NFs with regard to their fabrication process, properties, and applications. We find that surface activity of electrospun ceramic NFs is improved by post pyrolysis, hydrothermal, and carbothermal processes. Also, when combined with another surface modification methods, electrospun ceramic NFs result in the advancement of properties and widening of the application domains. With the decrease in diameter and length of a fiber, many properties of fibrous materials are modified; characteristics of such ceramic NFs are different from their wide and long (bulk counterparts. In this article, electrospun ceramic NFs are reviewed with an emphasis on their applications as catalysts, membranes, sensors, biomaterials, fuel cells, batteries, supercapacitors, energy harvesting systems, electric and magnetic parts, conductive wires, and wearable electronic textiles. Furthermore, properties of ceramic nanofibers, which enable the above applications, and techniques to characterize them are briefly outlined.

  15. Preparation and Characterization of Pd Modified TiO2 Nanofiber Catalyst for Carbon–Carbon Coupling Heck Reaction

    OpenAIRE

    Nyangasi, Leah O.; Andala, Dickson M.; Charles O. Onindo; Ngila, Jane C.; Banothile C. E. Makhubela; Eric M. Ngigi

    2017-01-01

    TiO2 fibers were prepared through electrospinning of poly methyl methacrylate (PMMA) and titanium isopropoxide (TIP) solution followed by calcination of fibers in air at 500°C. Cetyltrimethylammonium bromide (CTAB) protected palladium nanoparticles (Pd NPs) prepared through reduction method were successfully adsorbed on the TiO2 nanofibers (NF). Combined studies of X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) indicated that the synthe...

  16. Enhanced conversion efficiency in dye-sensitized solar cells based on bilayered nano-composite photoanode film consisting of TiO2 nanoparticles and nanofibers.

    Science.gov (United States)

    Du, P F; Song, L X; Xiong, J

    2014-06-01

    Novel TiO2 nanoparticles/nanofibers (NPs/NFs) bilayered nano-composite photoanode film for dye-sensitized solar cells (DSSCs) was fabricated through the combination of spin-coating and electrospinning. The NPs and NFs layers have complementary roles. The underlaid spin-coated NPs layer provides the photoanode film with higher specific surface area for dye adsorption and improved adhesion to conductive glass substrate. The overlaid electrospun NFs layer endows the photoanode film with better dye-loading and light-harvesting capabilities due to its porous meshwork structure. And the NFs layer also offers larger pore volume, which can facilitate the electrolyte diffusion and the activity regeneration of dye sensitizers. As a result, the electron transport is accelerated while the charge recombination is suppressed. Ascribing to the synergic effect of the NPs and NFs layers, the TiO2 NPs/NFs-based DSSCs achieve a conversion efficiency of 4.46%, which is nearly 14% higher than that of the pure TiO2 NPs-based ones.

  17. Potential of Electrospun Nanofibers for Biomedical and Dental Applications

    Directory of Open Access Journals (Sweden)

    Muhammad Zafar

    2016-01-01

    Full Text Available Electrospinning is a versatile technique that has gained popularity for various biomedical applications in recent years. Electrospinning is being used for fabricating nanofibers for various biomedical and dental applications such as tooth regeneration, wound healing and prevention of dental caries. Electrospun materials have the benefits of unique properties for instance, high surface area to volume ratio, enhanced cellular interactions, protein absorption to facilitate binding sites for cell receptors. Extensive research has been conducted to explore the potential of electrospun nanofibers for repair and regeneration of various dental and oral tissues including dental pulp, dentin, periodontal tissues, oral mucosa and skeletal tissues. However, there are a few limitations of electrospinning hindering the progress of these materials to practical or clinical applications. In terms of biomaterials aspects, the better understanding of controlled fabrication, properties and functioning of electrospun materials is required to overcome the limitations. More in vivo studies are definitely required to evaluate the biocompatibility of electrospun scaffolds. Furthermore, mechanical properties of such scaffolds should be enhanced so that they resist mechanical stresses during tissue regeneration applications. The objective of this article is to review the current progress of electrospun nanofibers for biomedical and dental applications. In addition, various aspects of electrospun materials in relation to potential dental applications have been discussed.

  18. Photocatalytic Degradation of 2-Chlorophenol Using Ag-Doped TiO2 Nanofibers and a Near-UV Light-Emitting Diode System

    Directory of Open Access Journals (Sweden)

    Ju-Young Park

    2014-01-01

    Full Text Available This report investigated the photocatalytic degradation of 2-chlorophenol using TiO2 nanofibers and Ag-doped TiO2 nanofibers, synthesized using the sol-gel and electrospinning techniques, and an ultraviolet light-emitting diode (UV-LED system as a UV light source. The crystallite size of the Ag-doped TiO2 nanofibers was smaller than that of the TiO2 nanofibers, because silver retrained phase transformation not only controls the phase transformation but also inhibits the growth of anatase crystallites. The activation energies for the grain growth of the TiO2 nanofibers and the Ag-doped TiO2 nanofibers were estimated to be 20.84 and 27.01 kJ/mol, respectively. The photocatalytic degradation rate followed a pseudo-first-order equation. The rate constants (k of the TiO2 nanofibers and the Ag-doped TiO2 nanofibers were 0.056 and 0.144 min−1, respectively.

  19. Synthesis and photocatalytic activity of electrospun niobium oxide nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Shishun [Institute of Electro Ceramics and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Zuo, Ruzhong, E-mail: piezolab@hfut.edu.cn [Institute of Electro Ceramics and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Liu, Yi [Institute of Electro Ceramics and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009 (China); Wang, Yu [Department of Applied Physics and Materials Research Center, The Hong Kong Polytechnic University, Hong Kong (China)

    2013-03-15

    Graphical abstract: Different morphologies are obtained for the electrospun niobium oxide nanofibers with different phase structures. The nanofibers of the two phase structures present different band gap value and the light absorption. Hexagonal phase nanofibers show better photocatalytic activity compared with the orthorhombic nanofibers. Highlights: ► Niobium oxide nanofibers of two phase structures were fabricated by electrospinning. ► Photocatalytic properties of the niobium oxide nanofibers were first explored. ► Nanofibers of different phase structures showed different photocatalytic activities. ► Reasons for the differences in the photocatalysis were carefully discussed. - Abstract: Niobium oxide (Nb{sub 2}O{sub 5}) nanofibers have been synthesized by sol–gel based electrospinning technique. Pure hexagonal phase (H-Nb{sub 2}O{sub 5}) and orthorhombic phase (O-Nb{sub 2}O{sub 5}) nanofibers were obtained by thermally annealing the electrospun Nb{sub 2}O{sub 5}/polyvinylpyrrolidone composite fibers in air at 500 °C and 700 °C, respectively. The fibers were characterized using the X-ray diffraction, scanning electron microscopy, specific surface area analyzer and UV–vis diffuse reflectance spectroscopy. Photocatalytic activities of the obtained nanofibers were evaluated depending on the degradation of methyl orange. The results indicate that the heat-treatment temperature, the crystalline structure and the morphology affected the physical and chemical properties of the as-prepared Nb{sub 2}O{sub 5} nanofibers. The H-Nb{sub 2}O{sub 5} nanofibers obtained at lower temperature showed better potential for the application as a promising photocatalyst.

  20. Study on the Electrospun CNTs/Polyacrylonitrile-Based Nanofiber Composites

    Directory of Open Access Journals (Sweden)

    Bo Qiao

    2011-01-01

    Full Text Available CNTs/PAN nanofibers were electrospun from PAN-based solution for the preparation of carbon nanofiber composites. The as-spun polyacrylonitrile-based nanofibers were hot-stretched by weighing metal in a temperature controlled oven. Scanning electron microscopy (SEM and transmission electron microscopy (TEM were used to characterize the morphology of the nanofibers, which indicated that carbon nanotubes were dispersed well in the composites and were completely wrapped by PAN matrix. Because of the strong interfacial interaction between CNTs and PAN, the CNTs/PAN application performance will be enhanced correspondingly, such as the mechanical properties and the electrical conductivity. It was concluded that the hot-stretched CNTs/PAN nanofibers can be used as a potential precursor to produce high-performance carbon composites.

  1. Electrospun nanofibers: New generation materials for advanced applications

    Energy Technology Data Exchange (ETDEWEB)

    Thenmozhi, S. [Inorganic & Nanomaterials Research Laboratory, Department of Chemistry, Bharathiar University, Coimbatore 641 046 (India); DRDO-BU CLS, Bharathiar University Campus, Coimbatore 641 046 (India); Dharmaraj, N., E-mail: dharmaraj@buc.edu.in [Inorganic & Nanomaterials Research Laboratory, Department of Chemistry, Bharathiar University, Coimbatore 641 046 (India); Kadirvelu, K. [DRDO-BU CLS, Bharathiar University Campus, Coimbatore 641 046 (India); Kim, Hak Yong [Department of Textile Engineering, Chonbuk National University, Chonju 561-756 (Korea, Republic of)

    2017-03-15

    Highlights: • A review covering important aspects of electrospinning technique is presented. • Applications of nanofibers in various fields are reviewed. • Possibility to up-scale electrospinning technique to industry also included. - Abstract: Electrospinning (E-spin) is a unique technique to fabricate polymeric as well as metal oxide nanofibers. Research on electrospun nanofibers is a very active field in material science owing to their novel applications in diverse domains. The main focus of this review is to provide an insight into E-spin technique by understanding the working principle, influencing parameters and applications of nanofibers in different walks of life. Several hundreds of papers are published on the preparation, modification and applications of nanofibers produced by E-spin technique in the areas like sensor development, decontamination, energy storage, biomedical and catalysis etc. Details on the industrial scale development of E-spin technique, current scenario and future developments are also covered in this review.

  2. Mechanically enhanced electrospun nanofibers for wastewater treatment

    Science.gov (United States)

    Yalcinkaya, Fatma

    2017-11-01

    A novel high-performance polyamide 6, polyacrylonitrile and polyvinylidene fluoride nanofibers were fabricated using industrial production Nanospider equipment for liquid filtration as microfilters. The application of nanofibers has been hindered by their poor mechanical strength. This work developed a feasible approach to preparing mechanically strong nanofiber webs. The mechanical strength of the nanofibers was enhanced using special lamination technique on a supporting layer. Experimental results show that the mechanical strength of the nanofibers enhanced more than 5 times while high porosity and liquid permeability retain. The separation results indicate that nanofibers have a potential to be used in liquid filters.

  3. NOx Selective Catalytic Reduction (SCR) on Self-Supported V-W-doped TiO2 Nanofibers

    DEFF Research Database (Denmark)

    Marani, Debora; Silva, Rafael Hubert; Dankeaw, Apiwat

    2017-01-01

    Electrospun V–W–TiO2 catalysts, resulting in a solid solution of V and W in the anatase phase, are prepared as nonwoven nanofibers for NOx selective catalytic reduction (SCR). Preliminary catalytic characterization indicates their superior NOx conversion efficiency to the-state-of-the-art material...

  4. Perspective of electrospun nanofibers in energy and environment

    Directory of Open Access Journals (Sweden)

    Jayaraman Sundaramurthy

    2014-06-01

    Full Text Available This review summarizes the recent developments of electrospun semiconducting metal oxide/polymer composite nanostructures in energy and environment related applications. Electrospinning technique has the advantage of synthesizing nanostructures with larger surface to volume ratio, higher crystallinity with phase purity and tunable morphologies like nanofibers, nanowires, nanoflowers and nanorods. The electrospun nanostructures have exhibited unique electrical, optical and catalytic properties than the bulk counter parts as well as nanomaterials synthesized through other approaches. These nanostructures have improved diffusion and interaction of molecules, transfer of electrons along the matrix and catalytic properties with further surface modification and functionalization with combination of metals and metal oxides.

  5. Hierarchical interfaces induce high dielectric permittivity in nanocomposites containing TiO2@BaTiO3 nanofibers.

    Science.gov (United States)

    Zhang, Xin; Chen, Weiwei; Wang, Jianjun; Shen, Yang; Gu, Lin; Lin, Yuanhua; Nan, Ce-Wen

    2014-06-21

    Interface issues are common and crucial in nanocomposites or nanohybrid systems since the interface area is enormous on the nanoscale. In the 0-3 dimensional polymer nanocomposites, in which nano-inclusions (0-dimension) are embedded in a 3-dimensionally connected polymer matrix, enhanced dielectric permittivity could be induced by the interfacial polarization at the interfaces between the nano-inclusions and the polymer matrix. In this contribution, we propose and demonstrate that the topological structure of the interface plays an equally important role as the area of the interface in determining the dielectric polarization of polymer nanocomposites. TiO2 nanofibers embedded with BaTiO3 nanoparticles are prepared via electrospinning and then fused with polyvinyl difluoride (PVDF) into polymer nanocomposite films. Modulation of hierarchical interfaces is thus achieved for these nanocomposites. The confinement of these additional interfaces inside the TiO2 nanofibers leads to percolated networks formed by the interfacial regions. The dielectric permittivity of the polymer nanocomposites is thus enhanced by ∼300% over the PVDF matrix at a low filler loading of 11 vol%. A phase-field simulation study indicates that the enhanced dielectric permittivity could be attributed to the increased polarization in the percolated interfacial regions inside the TiO2 nanofibers. The instantaneous electrical breakdown of the TiO2@BaTiO3 nanofibers studied by the in situ transmission electron microscopy method further reveals the striking feature that the breakdown behavior of the nanofibers changes from semiconductive to metallic with the incorporation of insulating BaTiO3 nanoparticles.

  6. Polypyrrole-coated electrospun PLGA nanofibers for neural tissue applications.

    Science.gov (United States)

    Lee, Jae Y; Bashur, Chris A; Goldstein, Aaron S; Schmidt, Christine E

    2009-09-01

    Electrospinning is a promising approach to create nanofiber structures that are capable of supporting adhesion and guiding extension of neurons for nerve regeneration. Concurrently, electrical stimulation of neurons in the absence of topographical features also has been shown to guide axonal extension. Therefore, the goal of this study was to form electrically conductive nanofiber structures and to examine the combined effect of nanofiber structures and electrical stimulation. Conductive meshes were produced by growing polypyrrole (PPy) on random and aligned electrospun poly(lactic-co-glycolic acid) (PLGA) nanofibers, as confirmed by scanning electron micrographs and X-ray photon spectroscopy. PPy-PLGA electrospun meshes supported the growth and differentiation of rat pheochromocytoma 12 (PC12) cells and hippocampal neurons comparable to non-coated PLGA control meshes, suggesting that PPy-PLGA may be suitable as conductive nanofibers for neuronal tissue scaffolds. Electrical stimulation studies showed that PC12 cells, stimulated with a potential of 10 mV/cm on PPy-PLGA scaffolds, exhibited 40-50% longer neurites and 40-90% more neurite formation compared to unstimulated cells on the same scaffolds. In addition, stimulation of the cells on aligned PPy-PLGA fibers resulted in longer neurites and more neurite-bearing cells than stimulation on random PPy-PLGA fibers, suggesting a combined effect of electrical stimulation and topographical guidance and the potential use of these scaffolds for neural tissue applications.

  7. Polypyrrole-Coated Electrospun PLGA Nanofibers for Neural Tissue Applications

    Science.gov (United States)

    Lee, Jae Young; Bashur, Chris A.; Goldstein, Aaron S.; Schmidt, Christine E.

    2009-01-01

    Electrospinning is a promising approach to create nanofiber structures that are capable of supporting adhesion and guiding extension of neurons for nerve regeneration. Concurrently, electrical stimulation of neurons in the absence of topographical features also has been shown to guide axonal extension. Therefore, the goal of this study was to form electrically conductive nanofiber structures and to examine the combined effect of nanofiber structures and electrical stimulation. Conductive meshes were produced by growing polypyrrole (PPy) on random and aligned electrospun poly(lactic-co-glycolic acid) (PLGA) nanofibers, as confirmed by scanning electron micrographs and X-ray photon spectroscopy. PPy-PLGA electrospun meshes supported the growth and differentiation of rat pheochromocytoma 12 (PC12) cells and hippocampal neurons comparable to non-coated PLGA control meshes, suggesting that PPy-PLGA may be suitable as conductive nanofibers for neuronal tissue scaffolds. Electrical stimulation studies showed that PC12 cells, stimulated with a potential of 10 mV/cm on PPy-PLGA scaffolds, exhibited 40–50% longer neurites and 40–90% more neurite formation compared to unstimulated cells on the same scaffolds. In addition, stimulation of the cells on aligned PPy-PLGA fibers resulted in longer neurites and more neurite-bearing cells than stimulation on random PPy-PLGA fibers, suggesting a combined effect of electrical stimulation and topographical guidance and the potential use of these scaffolds for neural tissue applications. PMID:19501901

  8. Fabrication of a TiO2@porphyrin nanofiber hybrid material: a highly efficient photocatalyst under simulated sunlight irradiation

    Science.gov (United States)

    La, Duong Duc; Rananaware, Anushri; Phuong Nguyen Thi, Hoai; Jones, Lathe; Bhosale, Sheshanath V.

    2017-03-01

    The solar spectrum consists of 8% UV radiation, while 45% of solar energy is from visible light. It is therefore desirable to fabricate a hybrid material which is able to harvest energy from a wide range of photons from the sun for applications such as solar cells, photovoltaics, and photocatalysis. In this study we report on the fabrication of a TiO2@porphyrin hybrid material by surfactant-assisted co-assembly of monomeric porphyrin molecules with TiO2 nanoparticles. The obtained TiO2@porphyrin composite shows excellent integration of TiO2 particles with diameters of 15-30 nm into aggregated porphyrin nanofibers, which have a width of 70-90 nm and are several µm long. SEM, XPS, XRD, FTIR, UV-Vis and fluorescence spectroscopy were employed to characterize the TiO2@TCPP hybrid material. This material exhibits efficient photocatalytic performance under simulated sunlight, due to synergistic photocatalytic activities of the porphyrin aggregates in visible light and TiO2 particles in the UV region. A plausible mechanism for photocatalytic degradation is also proposed and discussed.

  9. Nitrogen-doped carbon-embedded TiO2 nanofibers as promising oxygen reduction reaction electrocatalysts

    Science.gov (United States)

    Hassen, D.; Shenashen, M. A.; El-Safty, S. A.; Selim, M. M.; Isago, H.; Elmarakbi, A.; El-Safty, A.; Yamaguchi, H.

    2016-10-01

    The development of inexpensive and effective electrocatalysts for oxygen reduction reaction (ORR) as a substitute for commercial Pt/C catalyst is an important issue in fuel cells. In this paper, we report on novel fabrication of self-supported nitrogen-doped carbon-supported titanium nanofibers (Nsbnd TiO2@C) and carbon-supported titanium (TiO2@C) electrocatalysts via a facile electrospinning route. The nitrogen atom integrates physically and homogenously into the entire carbon-titanium structure. We demonstrate the catalytic performance of Nsbnd TiO2@C and TiO2@C for ORR under alkaline conditions in comparison with Pt/C catalyst. The Nsbnd TiO2@C catalyst shows excellent ORR reactivity and durability. Interestingly, among all the catalysts used in this ORR, Nsbnd TiO2@C-0.75 exhibits remarkable competitive oxygen reduction activity in terms of current density and onset potential, as well as superior methanol tolerance. Such tolerance attributes to maximizing the diffusion of trigger pulse electrons during catalytic reactions because of enhanced electronic features. Results indicate that our fabrication strategy can provide an opportunity to produce a simple, efficient, cost-effective, and promising ORR electrocatalyst for practical applications in energy conversion and storage technologies.

  10. Chemistry on electrospun polymeric nanofibers: merely routine chemistry or a real challenge?

    Science.gov (United States)

    Agarwal, Seema; Wendorff, Joachim H; Greiner, Andreas

    2010-08-03

    Nanofiber-based non-wovens can be prepared by electrospinning. The chemical modification of such nanofibers or chemistry using nanofibers opens a multitude of application areas and challenges. A wealth of chemistry has been elaborated in recent years on and with electrospun nanofibers. Known methods as well as new methods have been applied to modify the electrospun nanofibers and thereby generate new materials and new functionalities. This Review summarizes and sorts the chemistry that has been reported in conjunction with electrospun nanofibers. The major focus is on catalysis and nanofibers, enzymes and nanofibers, surface modification for biomedical and specialty applications, coatings of fibers, crosslinking, and bulk modifications. A critical focus is on the question: what could make chemistry on or with nanofibers different from bulk chemistry? Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Engineered Polymer Composites Through Electrospun Nanofiber Coating of Fiber Tows

    Science.gov (United States)

    Kohlman, Lee W.; Bakis, Charles; Williams, Tiffany S.; Johnston, James C.; Kuczmarski, Maria A.; Roberts, Gary D.

    2014-01-01

    Composite materials offer significant weight savings in many aerospace applications. The toughness of the interface of fibers crossing at different angles often determines failure of composite components. A method for toughening the interface in fabric and filament wound components using directly electrospun thermoplastic nanofiber on carbon fiber tow is presented. The method was first demonstrated with limited trials, and then was scaled up to a continuous lab scale process. Filament wound tubes were fabricated and tested using unmodified baseline towpreg material and nanofiber coated towpreg.

  12. Hydrogen sorption and permeability of compacted LiBH4 nanoconfined into activated carbon nanofibers impregnated with TiO2

    Science.gov (United States)

    Sitthiwet, Chongsutthamani; Thiangviriya, Sophida; Thaweelap, Natthaporn; Meethom, Sukanya; Kaewsuwan, Dechmongkhon; Chanlek, Narong; Utke, Rapee

    2017-11-01

    Activated carbon nanofibers impregnated with titanium (IV) oxide (TiO2), denoted as ACNF-Ti are prepared by carbonization and activation of electrospun nanofibers of polyacrylonitrile (PAN)-titanium (IV) isopropoxide composite. Pristine LiBH4 and nanoconfined LiBH4 in ACNF-Ti, denoted as LiBH4-ACNF-Ti are compacted under the pressures of 434 and 868 MPa. Dehydrogenation temperature of compacted LiBH4 increases (up to 485 °C) with compaction pressure due to poor hydrogen permeability. In the case of compacted LiBH4-ACNF-Ti, major dehydrogenation temperature at 352-359 °C and hydrogen content liberated (74-76% of theoretical capacity) are obtained despite enhanced compaction pressure. Mechanical stability during cycling of compacted LiBH4-ACNF-Ti is achieved. Although hydrogen permeability of compacted LiBH4-ACNF-Ti improves with enhanced compaction pressure, detrimental kinetics and reversibility are detected. Since the fibrous structure of ACNF-Ti are brittle, the broken and/or shorten fibers are observed after compaction under high pressure. The latter results in not only inferior nanoconfinement of LiBH4 into ACNF-Ti, but also agglomeration of hydride materials upon cycling.

  13. Electrospun Carbon Nanotube-Reinforced Nanofiber.

    Science.gov (United States)

    Kim, Sung Mm; Hee Kim, Sung; Choi, Myong Soo; Lee, Jun Young

    2016-03-01

    We fabricated multi-walled carbon nanotube (MWNT) reinforced polyurethane (PU) nanofiber (MWNT-PU) web via electrospinning. In order to optimize the electrospinning conditions, we investigated the effects of various parameters including kind of solvent, viscosity of the spinning solution, and flow rate on the spinnability and properties of nanofiber. N,N-dimethylformamide (DMF), tetrahydrofuran (THF) and their mixture with various volume ratio were used as the spinning solvent. Morphology of the nanofiber was studied using scanning electron microscope (SEM) and transmission electron microscope (TEM), confirming successful fabrication of MWNT-PU nanofiber web with uniform dispersion of MWNT in longitudinal direction of the fiber. The MWNT-PU nanofiber web exhibited two times higher tensile strength than PU nanofiber web. We also fabricated electrically conducting MWNT-PU nanofiber web by coating poly(3,4-ehtylenedioxythiophene) (PEDOT) on the surface of MWNT-PU nanofiber web for electromagnetic interference (EMI) shielding application. The electromagnetic interference shielding effectiveness (EMI SE) was quite high as 25 dB in the frequency range from 50 MHz to 10 GHz.

  14. Development of Protective Clothing against Nanoparticle Based on Electrospun Nanofibers

    Directory of Open Access Journals (Sweden)

    M. Faccini

    2012-01-01

    Full Text Available In this paper, the development of efficient protective clothing against nanoparticulate aerosols is presented. Nanofibrous mats of polyamide 6 (PA6 were deposited onto a nonwoven viscose substrate by electrospinning technique. The influence of electrospinning parameters, including solution concentration, viscosity, and conductivity, was studied for the production of nonwovens with controlled fiber diameter showing a size distribution ranging from 66 to 195 nm. By varying several process parameters, textiles with different thickness of the nanofiber layer and thus air permeability were obtained. A hot-press lamination process using a thermoplastic resin as glue was applied to improve the adhesion of the nanofiber layer onto the textile support. After 1500 cycles of repeated compression and torsion, the nanofiber layer was still firmly attached to the support, while mechanical damage is visible in some areas. The penetration of NaCl particles with diameter ranging from 15 to 300 nm through the electrospun textiles was found to be strongly dependent on nanofiber layer thickness. A really thin nanofiber coating provides up to 80% retention of 20 nm size particles and over 50% retention of 200 nm size nanoparticles. Increasing the thickness of the nanofiber mat, the filtration efficiency was increased to over 99% along the whole nanoparticle range. The results obtained highlight the potential of nanofibers in the development of efficient personal protective equipments against nanoparticles.

  15. Potential of Electrospun Nanofibers for Biomedical and Dental Applications

    OpenAIRE

    Muhammad Zafar; Shariq Najeeb; Zohaib Khurshid; Masoud Vazirzadeh; Sana Zohaib; Bilal Najeeb; Farshid Sefat

    2016-01-01

    Electrospinning is a versatile technique that has gained popularity for various biomedical applications in recent years. Electrospinning is being used for fabricating nanofibers for various biomedical and dental applications such as tooth regeneration, wound healing and prevention of dental caries. Electrospun materials have the benefits of unique properties for instance, high surface area to volume ratio, enhanced cellular interactions, protein absorption to facilitate binding sites for cell...

  16. One-step electrospinning route of SrTiO3-modified Rutile TiO2nanofibers and its photocatalytic properties

    Science.gov (United States)

    Zhao, Weijie; Zhang, Jing; Pan, Jiaqi; Qiu, Jianfeng; Niu, Jiantao; Li, Chaorong

    2017-05-01

    The SrTiO3 modified rutile TiO2 composite nanofibers were synthesized by a simple electrospinning technique. The result of XRD, SEM and TEM indicate that the SrTiO3/TiO2 heterojuction has been prepared successfully. Compared with the TiO2 and SrTiO3, the photocatalytic activity of the SrTiO3/TiO2 (rutile) for the degradation of methyl orange exhibits an obvious enhancement under UV illumination. which is almost 2 times than that of bare TiO2 (rutile) nanofiber. Further, the high crystallinity and photon-generated carrier separation of the SrTiO3/TiO2 heterojuction are considered as the main reason for this enhancement.

  17. Pipe-Wire TiO2-Sn@Carbon Nanofibers Paper Anodes for Lithium and Sodium Ion Batteries.

    Science.gov (United States)

    Mao, Minglei; Yan, Feilong; Cui, Chunyu; Ma, Jianmin; Zhang, Ming; Wang, Taihong; Wang, Chunsheng

    2017-06-14

    Metallic tin has been considered as one of the most promising anode materials both for lithium (LIBs) and sodium ion battery (NIBs) because of a high theoretical capacity and an appropriate low discharge potential. However, Sn anodes suffer from a rapid capacity fading during cycling due to pulverization induced by severe volume changes. Here we innovatively synthesized pipe-wire TiO 2 -Sn@carbon nanofibers (TiO 2 -Sn@CNFs) via electrospinning and atomic layer deposition to suppress pulverization-induced capacity decay. In pipe-wire TiO 2 -Sn@CNFs paper, nano-Sn is uniformly dispersed in carbon nanofibers, which not only act as a buffer material to prevent pulverization, but also serve as a conductive matrix. In addition, TiO 2 pipe as the protection shell outside of Sn@carbon nanofibers can restrain the volume variation to prevent Sn from aggregation and pulverization during cycling, thus increasing the Coulombic efficiency. The pipe-wire TiO 2 -Sn@CNFs show excellent electrochemical performance as anodes for both LIBs and NIBs. It exhibits a high and stable capacity of 643 mA h/g at 200 mA/g after 1100 cycles in LIBs and 413 mA h/g at 100 mA/g after 400 cycles in NIBs. These results would shed light on the practical application of Sn-based materials as a high capacity electrode with good cycling stability for next-generation LIBs and NIBs.

  18. Fabrication and characterization of polycaprolactone-graphene powder electrospun nanofibers

    Science.gov (United States)

    Ginestra, Paola; Ghazinejad, Maziar; Madou, Marc; Ceretti, Elisabetta

    2016-09-01

    Porous fibrous membranes having multiple scales geometries and tailored properties have become attractive microfabrication materials in recent years. Due to the feasibility of incorporating graphene in electrospun nanofibres and the growing interest on these nanomaterials, the present paper focuses on the electrospinning of Poly (ɛ-Caprolactone) (PCL) solutions in the presence of different amounts of Graphene platelets. Electrospinning is a process whereby ultrafine fibers are formed in a high-voltage electrostatic field. The morphological appearance, fiber diameter, and structure of PCL nanofibers produced by the electrospinning process were studied in the presence of different concentration of graphene. Moreover, the effect of a successful incorporation of graphene nanosheets into PCL polymer nanofibers was analyzed. Scanning electron microscope micrographs of the electrospun fibers showed that the average fiber diameter increases in the presence of graphene. Furthermore, the intrinsic properties developed due to the interactions of graphene and PCL improved the mechanical properties of the nanofibers. The results reveal the effect of various graphene concentrations on PCL and the strong interfacial interactions between the graphene platelets phase and the polymer matrix. The functional complexity of the electrospun fibers provides significant advantages over other techniques and shows the promise of these fibers for many applications including air/water filters, sensors, organic solar cells, smart textiles, biocompatible scaffolds for tissue engineering and load-bearing applications. Optimizing deposition efficiency, however, is a necessary milestone for the widespread use of this technique.

  19. Performance Enhancement of Dental Composites Using Electrospun Nanofibers

    Directory of Open Access Journals (Sweden)

    H. Dodiuk-Kenig

    2008-01-01

    Full Text Available The objective of the present study is to investigate the effect of electrospun nanofiber reinforcement on the properties of commercially available, hyperbranched polymer modified (Hybrane, 0.3 wt.% DSM dental formulations. The emergence of functionalized nanoscale reinforcements having large surface area (hundreds of square meters/gram has enabled the design of novel nanocomposites with new and complex structures leading to enhanced mechanical and physical properties. Electrospun nanofibers from a range of polymer chemistries (PVOH, PLLA, Nylon 6 have been investigated as a reinforcing phase at levels between 0.01 and 0.3 wt.%, with and without a silane coupling agent surface treatment. The experimental results indicate that 0.05 wt.% reinforcement with 250 nm diameter PVOH nanofibers leads to a 30% improvement in compressive strength, coupled with a shrinkage reduction of about 50%. Electrospun fiber reinforcement by other chemistries or at other diameters showed either no property improvement or led to property loss.

  20. A simple UV-ozone surface treatment to enhance photocatalytic performance of TiO 2 loaded polymer nanofiber membranes

    KAUST Repository

    Dilpazir, S.

    2016-01-29

    Homogeneously dispersed titanium dioxide loaded polyacrylonitrile nanofiber membranes with increased active mass loading, Ti3+ surface defects and hydrophilicity were fabricated by combining electrospinning and UV-ozone surface treatment. The photocatalytic activity improved by a factor of ∼2 and the kinetics of photodegradation switched from pseudo-first order to pseudo-second order with increasing TiO2 content with a maximum rate constant of 20.7 h-1. © The Royal Society of Chemistry 2016.

  1. Understanding the remarkable luminescence enhancement via SiO2 coating on TiO2:Eu3+ nanofibers.

    Science.gov (United States)

    Chang, Meiqi; Song, Yanhua; Sheng, Ye; Chen, Jie; Zou, Haifeng

    2017-07-05

    TiO2:Eu3+ nanofibers diameters can be tuned by changing the mixed solvent ratio are synthesized via the electrospinning technique. Concentration quenching phenomena and the relationship of the PL intensity ratio I(5D0-7F2)/I(5D0-7F1) with the Eu doping concentration are discussed. Notably, the luminescence intensity is enhanced by about 7.8 fold by coating SiO2 gel layer on the TiO2:Eu3+ nanofibers, which is successfully performed via a sol-gel process followed by calcination. Furthermore, these fibers are characterized systematically via X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-vis diffuse reflectance spectroscopy (UV-vis DRS), Fourier transform infrared spectroscopy (FT-IR), and photoluminescence (PL) spectroscopy. Additionally, their Judd-Ofelt and spectral parameters are calculated to investigate their local structures. The relatively low Ω2 value of the coated samples reveals a decrease in covalency in the Eu-O bonds and an increase in the symmetric nature of Eu3+, which indicate that the perturbation effect of the crystal field in the solid system is larger than that of the uncoated samples. FT-IR analysis indicates the formation of Ti-O-Si bonds, which provide the ligand field in the interface between the TiO2:Eu3+ nanofibers and SiO2 layer and can repair the surface unsaturated bonds. This reduces the selection rules for radiative transitions, thereby the state of the Eu3+ ions is converted from dormant to activated. Moreover, the silica coating stabilizes the surface of the TiO2:Eu3+ nanofibers and eliminates the surface defects. Finally, a detailed mechanism is proposed to explain the luminescence enhancement behavior.

  2. Electrospun Polymer Nanofibers Decorated with Noble Metal Nanoparticles for Chemical Sensing

    OpenAIRE

    Chen, Chen; Tang, Yongan; Vlahovic, Branislav; Yan, Fei

    2017-01-01

    The integration of different noble metal nanostructures, which exhibit desirable plasmonic and/or electrocatalytic properties, with electrospun polymer nanofibers, which display unique mechanical and thermodynamic properties, yields novel hybrid nanoscale systems of synergistic properties and functions. This review summarizes recent advances on how to incorporate noble metal nanoparticles into electrospun polymer nanofibers and illustrates how such integration paves the way towards chemical s...

  3. Electrospun polyvinyl alcohol-honey nanofibers

    OpenAIRE

    Wang Ping; He Ji-Huan

    2013-01-01

    This paper sugeests a method for fabrication of polyvinyl alcohol-honey nanofibers by electrospinning. Polyvinyl alcohol and honey are all biocompatible and environmentally friendly materials. This combination will lead to wide potential applications in various engineering fields.

  4. Electrospun composite nanofibers for functional applications

    Energy Technology Data Exchange (ETDEWEB)

    Sawicka, Katarzyna M., E-mail: ksawicka@notes.cc.sunysb.edu; Gouma, Perena [Stony Brook University, Materials Science and Engineering (United States)

    2006-12-15

    In this article an outline of studies conducted to date utilizing the process of electrospinning is presented. This overview for the first time focuses on research of composite nanofiber synthesis and their applications. The phenomenon of bringing materials to the nanometer scale not only improves their properties, but also creates entirely new ones. The electrospinning technique is a simple and versatile method that offers a time and cost effective production of strategic combinations of polymer and composites nanofibers useful for numerous applications highlighted in this review. The future prospects of the field are also examined.

  5. Wet-Laid Meets Electrospinning: Nonwovens for Filtration Applications from Short Electrospun Polymer Nanofiber Dispersions.

    Science.gov (United States)

    Langner, Markus; Greiner, Andreas

    2016-02-01

    Dispersions of short electrospun fibers are utilized for the preparation of nanofiber nonwovens with different weight area on filter substrates. The aerosol filtration efficiencies of suspension-borne nanofiber nonwovens are compared to nanofiber nonwovens prepared directly by electrospinning with similar weight area. The filtration efficiencies are found to be similar for both types of nonwovens. With this, a large potential opens for processing, design, and application of new nanofiber nonwovens obtained by wet-laying of short electrospun nanofiber suspensions. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Enhanced photocatalytic activity of electrospun nanofibrous TiO2/g-C3N4 heterojunction photocatalyst under simulated solar light

    Science.gov (United States)

    Wang, Chunlei; Hu, Liming; Chai, Bo; Yan, Juntao; Li, Jianfen

    2018-02-01

    Electrospun nanofibrous TiO2/g-C3N4 heterojunction photocatalysts with different TiO2 content have been synthesized via a facile electrospinning and subsequent in situ evaporation and calcination process for the first time, which are examined in terms of morphology, component content, optical properties, PL spectra, photocurrent response, EIS measurement, photocatalytic activity and mechanism. SEM images exhibit TiO2/g-C3N4-4 heterojunction photocatalyst possesses the excellent 1D structure. HRTEM and element mapping images confirm the formation of heterojunction structure. DRS tests identify that TiO2/g-C3N4-4 heterojunction exhibits the intensitive absorption in both UV and visible light region. The photoelectrochemical tests prove that the recombination between electrons and holes are effectively inhibited. Based on TG analysis and photodegradation experiments, TiO2/g-C3N4-4 heterojunction photocatalyst with TiO2 content of 29.30 wt% possesses the best photocatalytic degradation efficiency for the RhB among the g-C3N4, TiO2 and their mixture under simulated sunlight irradiation. Moreover, 1D morphology of TiO2/g-C3N4-4 heterojunction photocatalyst is in favor of separating from solution for reuse and transferring the electrons, and maintains a very high photocatalytic degradation efficiency of 96% even after four recycles experiments, which is beneficial for practical application.

  7. The Effect of Surfactants on the Diameter and Morphology of Electrospun Ultrafine Nanofiber

    Directory of Open Access Journals (Sweden)

    Jian-Yi Zheng

    2014-01-01

    Full Text Available Different surfactants are introduced to study the diameter and morphology transformation characteristics of electrospun nanofiber. Surfactants increase the net charge density and instability motion of charged jet. The instability motion provides a good way to stretch the charged jets into finer ones, by which the beaded structures are also prevented. Ultrafine nanofiber with average diameter less than 65 nm can be fabricated. The nanofiber diameter decreases with the increase of surfactant concentration in polymer solution. The nanofibers with anionic surfactant sodium dodecyl sulfate (SDS have the smallest diameter. The cationic surfactant hexadecyl trimethyl ammonium bromide (HTAB plays the best role to prevent the formation of beaded structures in nanofibers, and helps to increase the uniformity of electrospun nanofiber. The effects of surfactants on the nanofiber diameter and morphology have been studied, which would promote the industrial application of ultrafine polymeric nanofibers.

  8. Electrospun Nanofiber Scaffolds with Gradations in Fiber Organization

    Science.gov (United States)

    Khandalavala, Karl; Jiang, Jiang; Shuler, Franklin D.; Xie, Jingwei

    2015-01-01

    The goal of this protocol is to report a simple method for generating nanofiber scaffolds with gradations in fiber organization and test their possible applications in controlling cell morphology/orientation. Nanofiber organization is controlled with a new fabrication apparatus that enables the gradual decrease of fiber organization in a scaffold. Changing the alignment of fibers is achieved through decreasing deposition time of random electrospun fibers on a uniaxially aligned fiber mat. By covering the collector with a moving barrier/mask, along the same axis as fiber deposition, the organizational structure is easily controlled. For tissue engineering purposes, adipose-derived stem cells can be seeded to these scaffolds. Stem cells undergo morphological changes as a result of their position on the varied organizational structure, and can potentially differentiate into different cell types depending on their locations. Additionally, the graded organization of fibers enhances the biomimicry of nanofiber scaffolds so they more closely resemble the natural orientations of collagen nanofibers at tendon-to-bone insertion site compared to traditional scaffolds. Through nanoencapsulation, the gradated fibers also afford the possibility to construct chemical gradients in fiber scaffolds, and thereby further strengthen their potential applications in fast screening of cell-materials interaction and interfacial tissue regeneration. This technique enables the production of continuous gradient scaffolds, but it also can potentially produce fibers in discrete steps by controlling the movement of the moving barrier/mask in a discrete fashion. PMID:25938562

  9. Electrospun nanofibers-mediated on-demand drug release.

    Science.gov (United States)

    Chen, Menglin; Li, Yan-Fang; Besenbacher, Flemming

    2014-11-01

    A living system has a complex and accurate regulation system with intelligent sensor-processor-effector components to enable the release of vital bioactive substances on demand at a specific site and time. Stimuli-responsive polymers mimic biological systems in a crude way where an external stimulus results in a change in conformation, solubility, or alternation of the hydrophilic/hydrophobic balance, and consequently release of a bioactive substance. Electrospinning is a straightforward and robust method to produce nanofibers with the potential to incorporate drugs in a simple, rapid, and reproducible process. This feature article emphasizes an emerging area using an electrospinning technique to generate biomimetic nanofibers as drug delivery devices that are responsive to different stimuli, such as temperature, pH, light, and electric/magnetic field for controlled release of therapeutic substances. Although at its infancy, the mimicry of these stimuli-responsive nanofibers to the function of the living systems includes both the fibrous structural feature and bio-regulation function as an on demand drug release depot. The electrospun nanofibers with extracellular matrix morphology intrinsically guide cellular drug uptake, which will be highly desired to translate the promise of drug delivery for the clinical success. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Stability of β-carotene in polyethylene oxide electrospun nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Peinado, I., E-mail: irpeipar@upvnet.upv.es [Free University of Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Mason, M.; Romano, A. [Free University of Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Biasioli, F. [Department of Food Quality and Nutrition, Research and Innovation Centre, Fondazione Edmund Mach (FEM), via E. Mach 1, 38010 San Michele all ‘Adige, TN (Italy); Scampicchio, M., E-mail: matteo.scampicchio@unibz.it [Free University of Bolzano, Piazza Università 5, 39100 Bolzano (Italy)

    2016-05-01

    Highlights: • β-carotene was incorporated into PEO-nanofibers by electrospinning. • Properties of the fibers were analyzed by SEM, color analysis, and DSC. • TGA coupled to PTR–ms resulted promising to online-monitoring thermal degradation. • Thermal stability of βc increased after encapsulation into the PEO-nanofibers. - Abstract: β-carotene (βc) was successfully incorporated into electrospun nanofibers of poly-(ethylene oxide) (PEO) with the aim of prolonging its shelf life and thermal stability. The physical and thermal properties of the βc-PEO-nanofibers were determined by scanning electron microscopy (SEM), color analysis, and differential scanning calorimetry (DSC). The nanofibers of PEO and βc-PEO exhibited average fiber diameters of 320 ± 46 and 230 ± 21 nm, with colorimetric coordinates L* = 95.7 ± 2.4 and 89.4 ± 4.6 and b* = −0.5 ± 0.1 and 6.2 ± 3.0 respectively. Thermogravimetric analysis coupled with Proton Transfer–Mass Spectroscopy (TGA/PTR–ms) demonstrated that coated βc inside PEO nanofibers increased thermal stability when compared to standard βc in powder form. In addition, β-carotene in the membranes showed higher stability during storage when compared with β-carotene in solution with a decrease in concentration of 57 ± 4% and 70 ± 2% respectively, thus should extend the shelf life of this compound. Also, TGA coupled with PTR–MS resulted in a promising technique to online-monitoring thermal degradation.

  11. Highly stretchable electrospun conducting polymer nanofibers

    Science.gov (United States)

    Boubée de Gramont, Fanny; Zhang, Shiming; Tomasello, Gaia; Kumar, Prajwal; Sarkissian, Andranik; Cicoira, Fabio

    2017-08-01

    Biomedical electronics research targets both wearable and biocompatible electronic devices easily adaptable to specific functions. To achieve such goals, stretchable organic electronic materials are some of the most intriguing candidates. Herein, we develop highly stretchable poly-(3,4-ethylenedioxythiphene) (PEDOT) doped with tosylate (PEDOT:Tos) nanofibers. A two-step process involving electrospinning of a carrier polymer (with oxidant) and vapor phase polymerization was used to produce fibers on a polydimethylsiloxane substrate. The fibers can be stretched up to 140% of the initial length maintaining high conductivity.

  12. Electrospun nanofiber reinforcement of dental composites with electromagnetic alignment approach

    Energy Technology Data Exchange (ETDEWEB)

    Uyar, Tansel [Department of Biomedical Engineering, Başkent University Bağlıca Campus, 06530 Ankara (Turkey); Çökeliler, Dilek, E-mail: cokeliler@baskent.edu.tr [Department of Biomedical Engineering, Başkent University Bağlıca Campus, 06530 Ankara (Turkey); Doğan, Mustafa [Department of Electrical and Electronics Engineering, Başkent University, Ankara 06180 (Turkey); Koçum, Ismail Cengiz [Department of Biomedical Engineering, Başkent University Bağlıca Campus, 06530 Ankara (Turkey); Karatay, Okan [Department of Electrical and Electronics Engineering, Başkent University, Ankara 06180 (Turkey); Denkbaş, Emir Baki [Department of Chemistry, Biochemistry Division, Hacettepe University, Ankara (Turkey)

    2016-05-01

    Polymethylmethacrylate (PMMA) is commonly used as a base acrylic denture material with benefits of rapid and easy handling, however, when it is used in prosthetic dentistry, fracturing or cracking problems can be seen due to the relatively low strength issues. Besides, acrylic resin is the still prominent material for denture fabrication due to its handy and low cost features. Numerous proposed fillers that are used to produce PMMA composites, however electrospun polyvinylalcohol (PVA) nanofiber fillers for production of PMMA composite resins are not studied as much as the others. The other focus of the practice is to compare both mechanical properties and efficiency of aligned fibers versus non-aligned PVA nanofibers in PMMA based dental composites. Field-controlled electrospinning system is manufactured and provided good alignment in lab scale as one of contributions. Some novel auxiliary electrodes in controlled structure are augmented to obtain different patterns of alignment with a certain range of fiber diameters. Scanning electron microscopy is used for physical characterization to determine the range of fiber diameters. Non-woven fiber has no unique pattern due to chaotic nature of electrospinning process, but aligned fibers have round pattern or crossed lines. These produced fibers are structured as layer-by-layer form with different features, and these features are used in producing PMMA dental composites with different volume ratios. The maximum flexural strength figure shows that fiber load by weight of 0.25% w/w and above improves in the maximum level. As a result, mechanical properties of PMMA dental composites are improved by using PVA nanofibers as a filler, however the improvement was higher when aligned PVA nanofibers are used. The maximum values were 5.1 MPa (flexural strength), 0.8 GPa (elastic modulus), and 170 kJ/m{sup 3} (toughness) in three-point bending test. In addition to the positive results of aligned and non-aligned nanofibers it was

  13. Photochemical Activation of Electrospun In2O3 Nanofibers for High-Performance Electronic Devices.

    Science.gov (United States)

    Meng, You; Liu, Guoxia; Liu, Ao; Guo, Zidong; Sun, Wenjia; Shan, Fukai

    2017-03-29

    Electrospun metal oxide nanofibers have been regarded as promising blocks for large-area, low-cost, and one-dimensional electronic devices. However, the electronic devices based on electrospun nanofibers usually suffer from poor performance and inferior viability. Here, we report an efficient photochemical process using UV light generated by a high-pressure mercury lamp to promote the electrical performance of the nanofiber-based electronic devices. Such UV treatment can lead to strong photochemical activation of electrospun nanofibers, and therefore, a stable adherent nanofiber network and electronic-clean interface were formed. By use of UV treatment, high-performance indium oxide (In2O3) nanofiber based field-effect transistors (FETs) with highly efficient modulation of electrical characteristics have been successfully fabricated. To reduce the operating voltage and further improve the device performance, the In2O3 nanofiber FETs based on solution-processed high-k AlOx dielectrics were integrated and investigated. The as-fabricated In2O3/AlOx FETs exhibit superior electrical performance, including a high mobility of 19.8 cm2 V-1 s-1, a large on/off current ratio of 106, and high stability over time and cycling. The improved performance of the UV-treated FETs was further confirmed by the integration of the electrospun In2O3/AlOx FETs into inverters. This work presents an important advance toward the practical applications of electrospun nanofibers for functional electronic devices.

  14. Origin of high propagation loss in electrospun polymer nanofibers

    Science.gov (United States)

    Ishii, Yuya; Satozono, Shota; Kaminose, Ryohei; Fukuda, Mitsuo

    2014-06-01

    We evaluate optical propagation loss (α) in electrospun poly(methyl methacrylate) (PMMA) nanofibers with different wavelength (λ) and determine the origin of the loss. Aligned single electrospun nanofibers composed of PMMA and a small amount of an organic dye are fabricated with an average diameter of approximately 640 nm. After cladding seven fiber samples, α is evaluated to be 26-62 dB cm-1 at wavelengths 590-680 nm. Moreover, α depended linearly on λ-4, and from the fitting functions we determined the ratio of the following two possible losses for α: loss at the interface between the fiber-core and cladding because of non-uniformity within the fibers (αun), and loss because of excess light scattering in the fibers resulting from density inhomogeneity of PMMA (αsc). For the fibers, αun is evaluated to be 6.9-22 dB cm-1, which represents 19%-50% of α at λ of 650 nm with α ˜ αun + αsc. Thus, we conclude that the high α in these fibers originates from both their poor uniformity and density inhomogeneity. Furthermore, a quantitative investigation of uniformity in the individual fibers revealed that the root mean square roughness ranges from 5.5 nm to 9.0 nm and the theoretical value of αun was ˜1 dB cm-1 showing reasonable agreement with experimental data. These findings hold for low-loss polymer nanofiber waveguides, which have high aspect ratio and fine patterning even in three dimensions.

  15. Bi-layer collagen/microporous electrospun nanofiber scaffold improves the osteochondral regeneration.

    Science.gov (United States)

    Zhang, Shufang; Chen, Longkun; Jiang, Yangzi; Cai, Youzhi; Xu, Guowei; Tong, Tong; Zhang, Wei; Wang, Linlin; Ji, Junfeng; Shi, Peihua; Ouyang, Hong Wei

    2013-07-01

    An optimal scaffold is crucial for osteochondral regeneration. Collagen and electrospun nanofibers have been demonstrated to facilitate cartilage and bone regeneration, respectively. However, the effect of combining collagen and electrospun nanofibers on osteochondral regeneration has yet to be evaluated. Here, we report that the combination of collagen and electrospun poly-l-lactic acid nanofibers synergistically promotes osteochondral regeneration. We first fabricated bi-layer microporous scaffold with collagen and electrospun poly-l-lactic acid nanofibers (COL-nanofiber). Mesenchymal stem cells were cultured on the bi-layer scaffold and their adhesion, proliferation and differentiation were examined. Moreover, osteochondral defects were created in rabbits and implanted with COL-nanofiber scaffold. Cartilage and subchondral bone regeneration were evaluated at 6 and 12weeks after surgery. Compared with COL scaffold, cells on COL-nanofiber scaffold exhibited more robust osteogenic differentiation, indicated by higher expression levels of OCN and runx2 genes as well as the accumulation of calcium nodules. Furthermore, implantation of COL-nanofiber scaffold seeded with cells induced more rapid subchondral bone emergence, and better cartilage formation, which led to better functional repair of osteochondral defects as manifested by histological staining, biomechanical test and micro-computed tomography data. Our study underscores the potential of using the bi-layer microporous COL-nanofiber scaffold for the treatment of deep osteochondral defects. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. Synthesis of Flexible Aerogel Composites Reinforced with Electrospun Nanofibers and Microparticles for Thermal Insulation

    Directory of Open Access Journals (Sweden)

    Huijun Wu

    2013-01-01

    Full Text Available Flexible silica aerogel composites in intact monolith of 12 cm were successfully fabricated by reinforcing SiO2 aerogel with electrospun polyvinylidene fluoride (PVDF webs via electrospinning and sol-gel processing. Three electrospun PVDF webs with different microstructures (e.g., nanofibers, microparticles, and combined nanofibers and microparticles were fabricated by regulating electrospinning parameters. The as-electrospun PVDF webs with various microstructures were impregnated into the silica sol to synthesize the PVDF/SiO2 composites followed by solvent exchange, surface modification, and drying at ambient atmosphere. The morphologies of the PVDF/SiO2 aerogel composites were characterized and the thermal and mechanical properties were measured. The effects of electrospun PVDF on the thermal and mechanical properties of the aerogel composites were evaluated. The aerogel composites reinforced with electrospun PVDF nanofibers showed intact monolith, improved strength, and perfect flexibility and hydrophobicity. Moreover, the aerogel composites reinforced with the electrospun PVDF nanofibers had the lowest thermal conductivity (0.028 W·m−1·K−1. It indicates that the electrospun PVDF nanofibers could greatly improve the mechanical strength and flexibility of the SiO2 aerogels while maintaining a lower thermal conductivity, which provides increasing potential for thermal insulation applications.

  17. Electrospun composite nanofiber yarns containing oriented graphene nanoribbons.

    Science.gov (United States)

    Matsumoto, Hidetoshi; Imaizumi, Shinji; Konosu, Yuichi; Ashizawa, Minoru; Minagawa, Mie; Tanioka, Akihiko; Lu, Wei; Tour, James M

    2013-07-10

    The graphene nanoribbon (GNR)/carbon composite nanofiber yarns were prepared by electrospinning from poly(acrylonitrile) (PAN) containing graphene oxide nanoribbons (GONRs), and successive twisting and carbonization. The electrospinning process can exert directional shear force coupling with the external electric field to the flow of the spinning solution. During electrospinning, the well-dispersed GONRs were highly oriented along the fiber axis in an electrified thin liquid jet. The addition of GONRs at a low weight fraction significantly improved the mechanical properties of the composite nanofiber yarns. In addition, the carbonization of the matrix polymer enhanced not only the mechanical but also the electrical properties of the composites. The electrical conductivity of the carbonized composite yarns containing 0.5 wt % GONR showed the maximum value of 165 S cm(-1). It is larger than the maximum value of the reported electrospun carbon composite yarns. Interestingly, it is higher than the conductivities of both the PAN-based pristine CNF yarns (77 S cm(-1)) and the monolayer GNRs (54 S cm(-1)). These results and Raman spectroscopy supported the hypothesis that the oriented GONRs contained in the PAN nanofibers effectively functioned as not only the 1-D nanofiller but also the nanoplatelet promoter of stabilization and template agent for the carbonization.

  18. Proliferation of Genetically Modified Human Cells on Electrospun Nanofiber Scaffolds

    Directory of Open Access Journals (Sweden)

    Mandula Borjigin

    2012-01-01

    Full Text Available Gene editing is a process by which single base mutations can be corrected, in the context of the chromosome, using single-stranded oligodeoxynucleotides (ssODNs. The survival and proliferation of the corrected cells bearing modified genes, however, are impeded by a phenomenon known as reduced proliferation phenotype (RPP; this is a barrier to practical implementation. To overcome the RPP problem, we utilized nanofiber scaffolds as templates on which modified cells were allowed to recover, grow, and expand after gene editing. Here, we present evidence that some HCT116-19, bearing an integrated, mutated enhanced green fluorescent protein (eGFP gene and corrected by gene editing, proliferate on polylysine or fibronectin-coated polycaprolactone (PCL nanofiber scaffolds. In contrast, no cells from the same reaction protocol plated on both regular dish surfaces and polylysine (or fibronectin-coated dish surfaces proliferate. Therefore, growing genetically modified (edited cells on electrospun nanofiber scaffolds promotes the reversal of the RPP and increases the potential of gene editing as an ex vivo gene therapy application.

  19. Electrospun Polymer Nanofibers Reinforced by Tannic Acid/Fe+++ Complexes

    Directory of Open Access Journals (Sweden)

    Weiqiao Yang

    2016-09-01

    Full Text Available We report the successful preparation of reinforced electrospun nanofibers and fibrous mats of polyvinyl alcohol (PVA via a simple and inexpensive method using stable tannic acid (TA and ferric ion (Fe+++ assemblies formed by solution mixing and pH adjustment. Changes in solution pH change the number of TA galloyl groups attached to the Fe+++ from one (pH < 2 to two (3 < pH < 6 to three (pH < 7.4 and affect the interactions between PVA and TA. At pH ~ 5.5, the morphology and fiber diameter size (FDS examined by SEM are determinant for the mechanical properties of the fibrous mats and depend on the PVA content. At an optimal 8 wt % concentration, PVA becomes fully entangled and forms uniform nanofibers with smaller FDS (p < 0.05 and improved mechanical properties when compared to mats of PVA alone and of PVA with TA (p < 0.05. Changes in solution pH lead to beads formation, more irregular FDS and poorer mechanical properties (p < 0.05. The Fe+++ inclusion does not alter the oxidation activity of TA (p > 0.05 suggesting the potential of TA-Fe+++ assemblies to reinforce polymer nanofibers with high functionality for use in diverse applications including food, biomedical and pharmaceutical.

  20. A Review of Electrospun Conductive Polyaniline Based Nanofiber Composites and Blends: Processing Features, Applications, and Future Directions

    National Research Council Canada - National Science Library

    Abd Razak, Saiful Izwan; Wahab, Izzati Fatimah; Fadil, Fatirah; Dahli, Farah Nuruljannah; Md Khudzari, Ahmad Zahran; Adeli, Hassan

    2015-01-01

    .... Electrospun polyaniline (PANI) based nanofiber is one of the important new materials for the rapidly growing technology development such as nanofiber based sensor devices, conductive tissue engineering scaffold materials, super...

  1. Design and Characterization of Electrospun Polyamide Nanofiber Media for Air Filtration Applications

    NARCIS (Netherlands)

    Matulevicius, J; Kliucininkas, L; Martuzevicius, D; Krugly, E; Tichonovas, M.; Baltrusaitis, Jonas

    2014-01-01

    Electrospun polyamide 6 (PA 6) and polyamide 6/6 (PA 6/6) nanofibers were produced in order to investigate their experimental characteristics with the goal of obtaining filtration relevant fiber media. The experimental design model of each PA nanofibers contained the following variables: polymer

  2. Impact of post-treatment on the characteristics of electrospun poly (vinyl alcohol)/chitosan nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Susanto, H., E-mail: heru.susanto@undip.ac.id [Department of Chemical Engineering, Faculty of Engineering, Diponegoro University Jl. Prof. Soedarto-Tembalang, Semarang (Indonesia); Samsudin, A. M.; Faz, M. W.; Rani, M. P. H.

    2016-04-19

    Electrospun nanofibers have many advantages such as high porosity, easy to be fabricated in various size and high ratio of surface area to volume. This paper presents the preparation of electrospun PVA/Chitosan nanofibers and more specifically focuses on the effect of post-treatment on the permeability and morphology of electrospun PVA/chitosan nanofibers. The mixtures of various concentrations of PVA (6,7,8 wt%)and 2 wt%.chitosan solution (with the ratio of 3:1)were used in electrospun with a constant rate of 0.7 ml/hour. The post-treatment was conducted by immersing in a ethanol or glutaraldehyde solution to performed crosslink structure. The electrospun PVA/Chitosan nanofiber was characterized by scanning electron microscopy (SEM) and fourier transform infrared (FTIR) spectroscopy. The results revealed that the viscosity of the mixture solution is directly proportional to its concentration. Increasing the viscosity increased the diameter of fiber but also made the larger beads formation. FTIR measurement exhibited the existence of relevant functional groups of both PVA and chitosan in the composites.The crosslinked structure was found for the electrospun PVA/Chitosan nanofibers treated with glutaraldehyde solution.

  3. Antimicrobial electrospun silver-, copper- and zinc-doped polyvinylpyrrolidone nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Quirós, Jennifer [Department of Chemical Engineering, University of Alcalá, 28871 Alcalá de Henares, Madrid (Spain); Borges, João P. [CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Boltes, Karina [Department of Chemical Engineering, University of Alcalá, 28871 Alcalá de Henares, Madrid (Spain); Madrid Institute for Advanced Studies of Water (IMDEA Agua), Parque Científico Tecnológico, E-28805, Alcalá de Henares, Madrid (Spain); Rodea-Palomares, Ismael [Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Rosal, Roberto [Department of Chemical Engineering, University of Alcalá, 28871 Alcalá de Henares, Madrid (Spain); Madrid Institute for Advanced Studies of Water (IMDEA Agua), Parque Científico Tecnológico, E-28805, Alcalá de Henares, Madrid (Spain)

    2015-12-15

    Highlights: • Electrospun polyvinylpyrrolidone (PVP) nanofibers containing silver, copper, and zinc. • Antimicrobial effect for the bacteria Staphylococcus aureus and Escherichia coli. • Silver strongly reduced colony forming units and bacterial viability. • Silver, copper, and zinc led to a significant increase of non-viable cells on mats. - Abstract: The use of electrospun polyvinylpyrrolidone (PVP) nanofibers containing silver, copper, and zinc nanoparticles was studied to prepare antimicrobial mats using silver and copper nitrates and zinc acetate as precursors. Silver became reduced during electrospinning and formed nanoparticles of several tens of nanometers. Silver nanoparticles and the insoluble forms of copper and zinc were dispersed using low molecular weight PVP as capping agent. High molecular weight PVP formed uniform fibers with a narrow distribution of diameters around 500 nm. The fibers were converted into an insoluble network using ultraviolet irradiation crosslinking. The efficiency of metal-loaded mats against the bacteria Escherichia coli and Staphylococcus aureus was tested for different metal loadings by measuring the inhibition of colony forming units and the staining with fluorescent probes for metabolic viability and compromised membranes. The assays included the culture in contact with mats and the direct staining of surface attached microorganisms. The results indicated a strong inhibition for silver-loaded fibers and the absence of significant amounts of viable but non-culturable microorganisms. Copper and zinc-loaded mats also decreased the metabolic activity and cell viability, although in a lesser extent. Metal-loaded fibers allowed the slow release of the soluble forms of the three metals.

  4. Incorporation of ciprofloxacin/laponite in polycaprolactone electrospun nanofibers: drug release and antibacterial studies

    Science.gov (United States)

    Kalwar, Kaleemullah; Zhang, Xuan; Aqeel Bhutto, Muhammad; Dali, Li; Shan, Dan

    2017-12-01

    Electrospun nanofibers with sustained drug release are a challenge but it can be improved by using hydrophobic polymer. Polycaprolactone (PCL) is a hydrophobic and biocompatible polymer. In this work, we have proposed a drug release mechanism by preparation of ciprofloxacin (Cip)/Laponite (LAP) complex and then incorporation in PCL nanofibers through electrospinning technique. In addition, drug incorporation was confirmed by FTIR and morphology of electrospun nanofibers was revealed by SEM. Drug loading was measured by using spectrophotometer. PCL/LAP/Cip NFs proved sustained drug release as compared to PCL NFs and PCL/Cip NFs. Furthermore, PCL/LAP/Cip NFs were used as antimicrobial agent and higher effect measured.

  5. One-step electrospinning synthesis of TiO2/g-C3N4 nanofibers with enhanced photocatalytic properties

    Science.gov (United States)

    Tang, Qian; Meng, Xianfeng; Wang, Zhiying; Zhou, Jianwei; Tang, Hua

    2018-02-01

    TiO2/g-C3N4 composite nanofibers have been successfully synthesized by one-step electrospinning method, using titanium (IV) n-butoxide (TNBT) and urea as raw materials. The structure and compositions of TiO2/g-C3N4 samples are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Diffuse reflectance spectroscopy (DRS), Scanning electron microscopy (SEM), Transmission electron microscope (TEM), X-ray photoelectron spectrometer (XPS) and Brunauer-Emmett-Teller (BET), respectively. The results show that the porous uniform TiO2/g-C3N4 composite nanofibers, with diameter of 100-150 nm, can be successfully prepared through electrospinning method combining 550 °C calcination process. The photocatalytic activity is evaluated by the degradation of rhodamine B (RhB) under simulated solar light. The enhanced catalytic activity is attributed predominantly to the heterojunction between TiO2 and g-C3N4, which promotes the transferring of carriers and prohibits their recombination. With the optimal doping amount of 0.6 g urea (corresponding to 3 g TNBT), the TiO2/g-C3N4 composite nanofibers exhibit the highest rate towards the photocatalytic degradation of RhB. A diagram is presented to explicate the mechanism of the whole catalytic experiment. This study might provide a promising future of applying green catalysts to solving water pollution problems.

  6. Smart Electrospun Nanofibers for Controlled Drug Release: Recent Advances and New Perspectives

    Science.gov (United States)

    Weng, Lin; Xie, Jingwei

    2017-01-01

    In biological systems, chemical molecules or ions often release upon certain conditions, at a specific location, and over a desired period of time. Electrospun nanofibers that undergo alterations in the physicochemical characteristics corresponding to environmental changes have gained considerable interest for various applications. Inspired by biological systems, therapeutic molecules have been integrated with these smart electrospun nanofibers, presenting activation-modulated or feedback-regulated control of drug release. Compared to other materials like smart hydrogels, environment-responsive nanofiber-based drug delivery systems are relatively new but possess incomparable advantages due to their greater permeability, which allows shorter response time and more precise control over the release rate. In this article, we review the mechanisms of various environmental parameters functioning as stimuli to tailor the release rates of smart electrospun nanofibers. We also illustrate several typical examples in specific applications. We conclude this article with a discussion on perspectives and future possibilities in this field. PMID:25732665

  7. New strategy of photodynamic treatment of TiO2 nanofibers combined with celastrol for HepG2 proliferation in vitro

    Science.gov (United States)

    Li, Jingyuan; Wang, Xuemei; Jiang, Hui; Lu, Xiaohua; Zhu, Yudan; Chen, Baoan

    2011-08-01

    As one of the best biocompatible semiconductor nanomaterials, TiO2 nanofibers can act as a good photosensitizer material and show potential application in the field of drug carriers and photodynamic therapy to cure diseases. Celastrol, one of the active components extracted from T. wilfordii Hook F., was widely used in traditional Chinese medicine for many diseases. In this study, the cytotoxicity of celastrol for HepG2 cancer cells was firstly explored. The results showed that celastrol could inhibit cancer cell proliferation in a time-dependent and dose-dependent manner, inducing apoptosis and cell cycle arrest at G2/M phase in HepG2 cells. After the TiO2 nanofibers were introduced into the system of celastrol, the cooperation effect showed that the nanocomposites between TiO2 nanofibers and celastrol could enhance the cytotoxicity of celastrol for HepG2 cells and cut down the drug consumption so as to reduce the side-effect of the related drug. Associated with the photodynamic effect, it is evident that TiO2 nanofibers could readily facilitate the potential application of the active compounds from natural products like celastrol. Turning to the advantages of nanotechnology, the combination of nanomaterials with the related monomer active compounds of promising Chinese medicine could play an important role to explore the relevant mechanism of the drug cellular interaction and promote the potential application of TiO2 nanofibers in the clinical treatment.As one of the best biocompatible semiconductor nanomaterials, TiO2 nanofibers can act as a good photosensitizer material and show potential application in the field of drug carriers and photodynamic therapy to cure diseases. Celastrol, one of the active components extracted from T. wilfordii Hook F., was widely used in traditional Chinese medicine for many diseases. In this study, the cytotoxicity of celastrol for HepG2 cancer cells was firstly explored. The results showed that celastrol could inhibit cancer cell

  8. 3D imaging of cell interactions with electrospun PLGA nanofiber membranes for bone regeneration.

    Science.gov (United States)

    Stachewicz, Urszula; Qiao, Tuya; Rawlinson, Simon C F; Almeida, Filipe Veiga; Li, Wei-Qi; Cattell, Michael; Barber, Asa H

    2015-11-01

    The interaction between resident cells and electrospun nanofibers is critical in determining resultant osteoblast proliferation and activity in orthopedic tissue scaffolds. The use of techniques to evaluate cell-nanofiber interactions is critical in understanding scaffold function, with visualization promising unparalleled access to spatial information on such interactions. 3D tomography exploiting focused ion beam (FIB)-scanning electron microscopy (SEM) was used to examine electrospun nanofiber scaffolds to understand the features responsible for (osteoblast-like MC3T3-E1 and UMR106) cell behavior and resultant scaffold function. 3D imaging of cell-nanofiber interactions within a range of electrospun poly(d,l-lactide-co-glycolide acid) (PLGA) nanofiber scaffold architectures indicated a coherent interface between osteoblasts and nanofiber surfaces, promoting osteoblast filopodia formation for successful cell growth. Coherent cell-nanofiber interfaces were demonstrated throughout a randomly organized and aligned nanofiber network. Gene expression of UMR106 cells grown on PLGA fibers did not deviate significantly from those grown on plastic, suggesting maintenance of phenotype. However, considerably lower expression of Ibsp and Alpl on PLGA fibers might indicate that these cells are still in the proliferative phase compared with a more differentiated cell on plastic. This work demonstrates the synergy between designing electrospun tissue scaffolds and providing comprehensive evaluation through high resolution imaging of resultant 3-dimensional cell growth within the scaffold. Membranes made from electrospun nanofibers are potentially excellent for promoting bone growth for next-generation tissue scaffolds. The effectiveness of an electrospun membrane is shown here using high resolution 3D imaging to visualize the interaction between cells and the nanofibers within the membrane. Nanofibers that are aligned in one direction control cell growth at the surface of the

  9. Preparation and Characterization of Pd Modified TiO2 Nanofiber Catalyst for Carbon–Carbon Coupling Heck Reaction

    Directory of Open Access Journals (Sweden)

    Leah O. Nyangasi

    2017-01-01

    Full Text Available TiO2 fibers were prepared through electrospinning of poly methyl methacrylate (PMMA and titanium isopropoxide (TIP solution followed by calcination of fibers in air at 500°C. Cetyltrimethylammonium bromide (CTAB protected palladium nanoparticles (Pd NPs prepared through reduction method were successfully adsorbed on the TiO2 nanofibers (NF. Combined studies of X-ray diffraction (XRD, scanning electron microscope (SEM, and transmission electron microscope (TEM indicated that the synthesized Pd/TiO2 had anatase. BET indicated that the synthesized TiO2 and Pd/TiO2 had a surface area of 53.4 and 43.4 m2/g, respectively. The activity and selectivity of 1 mol% Pd/TiO2 in the Heck reaction have been investigated towards the Mizoroki-Heck carbon–carbon cross-coupling of bromobenzene (ArBr and styrene. Temperature, time, solvent, and base were optimized and catalyst was recycled thrice. 1H NMR and 13C NMR indicated that stilbene, a known compound from literature, was obtained in various Heck reactions at temperatures between 100°C and 140°C but the recyclability was limited due to some palladium leaching and catalyst poisoning which probably arose from some residual carbon from the polymer. The catalyst was found to be highly active under air atmosphere with reaction temperatures up to 140°C. Optimized reaction condition resulted in 89.7% conversions with a TON of 1993.4 and TOF value of 332.2 hr−1.

  10. Assessment of the short-term toxicity of TiO2nanofiber in Sprague Dawley rats.

    Science.gov (United States)

    Gato, Worlanyo E; Hunter, Daniel A; Byrd, Ian C; Mays, Christopher A; Yau, Wilson; Wu, Ji

    2017-06-01

    Synthetic nanomaterials have many unique chemical and physical properties, mainly due to their high specific surface area and quantum confinement effect. Specifically, titanium dioxide (TiO 2 ) nanomaterial has high stability, anticorrosive, and photocatalytic properties. However, there are concerns over adverse biological effects resulting from bioeffects. This study was to investigate adverse effects associated with acute ingestion of TiO 2 nanofiber (TDNF). TDNF was fabricated via electrospinning method, followed by dissolution in water. Six- to seven-week-old male Sprague Dawley rats were exposed to a total of 0, 40, and 60 ppm of TDNF for 2 weeks via oral gavage. Serum total protein and weight gain during the course of this study displayed marginal concentration-dependent alterations. These findings were followed by a global gene expression analysis to identify which transcripts might be responsive to TNDF toxicity. Differentially expressed mRNA levels were dose-dependently higher in animals exposed to TNDF. The majority of the affected genes were biochemically involved in immune response and inflammation. We believe this is due to the fact that TNDF is unable to penetrate the cell and forms phagocytosis sites that trigger inflammatory and immune response. All results taken together, short-term ingestion of TNDF produced marginal effects indicative of inflammation. Finally, the broad gene expression data were validated through quantification of immunoglobulin heavy chain alpha (Igha). Igha gene was upregulated in treated groups, showing similar expression patterns to the global gene expression data. © 2017 Wiley Periodicals, Inc.

  11. Influence of temperature on the photodegradation process using Ag-doped TiO2 nanostructures: Negative impact with the nanofibers

    DEFF Research Database (Denmark)

    Barakata, Nasser A.M.; Kanjwal, Muzafar Ahmed; Chronakis, Ioannis S.

    2013-01-01

    In this study, the influence of the temperature on the photodegradation process using Ag-doped TiO2 nanostructures was investigated. Two morphologies were used; nanoparticles and nanofibers. The nanofibers were synthesized by electrospinning of a sol–gel consisting of titanium isopropoxide, silver......-doped TiO2 nanofibers for all formulations. The nanoparticles were prepared from the same sol–gels, however, instead of spinning the gels were dried, grinded and sintered at 700 °C. Photodegradation under UV irradiation for the rhodamine B at 5, 15, 25, 45 and 55 °C were performed. For the nanoparticles...... the molecules escape from the active thin film surrounding the photocatalyst. Overall, this study shows that the nanofibrous morphology strongly enhances the surface activity of the photocatalyst which generates negative influence of the temperature....

  12. Influence of temperature on the photodegradation process using Ag-doped TiO2nanostructures: Negative impact with the nanofibers

    DEFF Research Database (Denmark)

    Barakata, Nasser A.M.; Kanjwal, Muzafar Ahmad; Chronakis, Ioannis S.

    In this study, the influence of the temperature on the photodegradation process using Ag-doped TiO2 nanostructures was investigated. Two morphologies were used; nanoparticles and nanofibers. The nanofibers were synthesized by electrospinning of a sol–gel consisting of titanium isopropoxide, silver......-doped TiO2 nanofibers for all formulations. The nanoparticles were prepared from the same sol–gels, however, instead of spinning the gels were dried, grinded and sintered at 700 °C. Photodegradation under UV irradiation for the rhodamine B at 5, 15, 25, 45 and 55 °C were performed. For the nanoparticles...... the molecules escape from the active thin film surrounding the photocatalyst. Overall, this study shows that the nanofibrous morphology strongly enhances the surface activity of the photocatalyst which generates negative influence of the temperature....

  13. Improvement of Polylactide Properties through Cellulose Nanocrystals Embedded in Poly(Vinyl Alcohol) Electrospun Nanofibers.

    Science.gov (United States)

    López de Dicastillo, Carol; Garrido, Luan; Alvarado, Nancy; Romero, Julio; Palma, Juan Luis; Galotto, Maria Jose

    2017-05-11

    Electrospun nanofibers of poly (vinyl alcohol) (PV) were obtained to improve dispersion of cellulose nanocrystals (CNC) within hydrophobic biopolymeric matrices, such as poly(lactic acid) (PLA). Electrospun nanofibers (PV/CNC)n were successfully obtained with a final concentration of 23% (w/w) of CNC. Morphological, structural and thermal properties of developed CNC and electrospun nanofibers were characterized. X-ray diffraction and thermal analysis revealed that the crystallinity of PV was reduced by the electrospinning process, and the incorporation of CNC increased the thermal stability of biodegradable nanofibers. Interactions between CNC and PV polymer also enhanced the thermal stability of CNC and improved the dispersion of CNC within the PLA matrix. PLA materials with CNC lyophilized were also casted in order to compare the properties with materials based on CNC containing nanofibers. Nanofibers and CNC were incorporated into PLA at three concentrations: 0.5%, 1% and 3% (CNC respect to polymer weight) and nanocomposites were fully characterized. Overall, nanofibers containing CNC positively modified the physical properties of PLA materials, such as the crystallinity degree of PLA which was greatly enhanced. Specifically, materials with 1% nanofiber 1PLA(PV/CNC)n presented highest improvements related to mechanical and barrier properties; elongation at break was enhanced almost four times and the permeation of oxygen was reduced by approximately 30%.

  14. Electrospun Carbon Nanofiber Membranes for Filtration of Nanoparticles from Water

    Directory of Open Access Journals (Sweden)

    Mirko Faccini

    2015-01-01

    Full Text Available Nowadays, hundreds of consumer products contain metal and metal oxide nanoparticles (NP; this increases the probability of such particles to be released to natural waters generating a potential risk to human health and the environment. This paper presents the development of efficient carboneous nanofibrous membranes for NP filtration from aqueous solutions. Free-standing carbon nanofiber (CNF mats with different fiber size distribution ranging from 126 to 554 nm in diameter were produced by electrospinning of polyacrylonitrile (PAN precursor solution followed by thermal treatment. Moreover, tetraethoxyorthosilicate was added to provide flexibility and increase the specific surface area of the CNF. The resulting membranes are bendable and mechanically strong enough to withstand filtration under pressure or vacuum. The experimental results of filtration revealed that the fabricated membranes could efficiently reject nanoparticles of different types (Au, Ag, and TiO2 and size (from 10 to 100 nm in diameter from aqueous solutions. It is worth mentioning that the removal of Ag NP with diameters as small as 10 nm was close to 100% with an extremely high flux of 47620 L m−2 h−1 bar−1.

  15. Multifunctional Electrospun Nanofibers Incorporated with an Anti-infection Drug and Immobilized with Proteins

    Science.gov (United States)

    Zhou, Shufei

    Electrospinning has been used to fabricate ultrafine fibers with sizes ranging from nano to micrometers. Nanofibers electrospun from biocompatible and biodegradable polymers have been extensively investigated for their potential applications in wound healing and tissue regeneration. These nanofiber materials can be modified to incorporate bioactive molecules, such as antibacterial agents that provide infection control, or functional proteins which promote cell proliferation and tissue reconstruction. Despite the numerous studies on the development and design of nanofibers for biomedical applications, there has been little research on multifunctional nanofibers that are incorporated with both antibacterial drug(s) and bioactive proteins. The objective of the current study is, therefore, to develop nanofibers that are functionalized by several bioactive molecules. In this study, electrospinning was utilized to fabricate nanofibers from biodegradable polymers PLLA (Poly-L-lactide) and the copolymer PLLA-PEG (Polyethylene glycol)-NH2.A water soluble antibiotic drug, Tetracycline Hydrochloride (TCH), was incorporated into the electrospun nanofibers via emulsion electrospinning. The TCH-loaded nanofibers were surface modified to produce functional groups that can be further conjugated with a model protein, Bovine Serum Albumin (BSA).Drug releasing profiles of the medicated nanofibers were monitored and their antimicrobial properties were evaluated. Proteins (BSAs) immobilized on the fiber surface were verified by ATR-FTIR. The number of immobilized BSAs was determined using a UV-Vis spectrophotometer. The results of the study suggested that this multifunctional nanofibrous material could be a promising material for wound dressing or scaffolds for tissue engineering.

  16. Cartilage tissue engineering using electrospun PCL nanofiber meshes and MSCs.

    Science.gov (United States)

    Alves da Silva, M L; Martins, A; Costa-Pinto, A R; Costa, P; Faria, S; Gomes, M; Reis, R L; Neves, N M

    2010-12-13

    Mesenchymal stem cells (MSCs) have been recognized for their ability to differentiate into cells of different tissues such as bone, cartilage, or adipose tissue, and therefore are of great interest for potential therapeutic strategies. Adherent, colony-forming, fibroblastic cells were isolated from human bone marrow aspirates, from patients undergoing knee arthroplasties, and the MSCs phenotype characterized by flow cytometry. Afterward, cells were seeded onto electrospun polycaprolactone nanofiber meshes and cultured in a multichamber flow perfusion bioreactor to determine their ability to produce cartilagineous extracellular matrix. Results indicate that the flow perfusion bioreactor increased the chondrogenic differentiation of hBM-MSCs, as confirmed either by morphological and RT-PCR analysis. Cartilage-related genes such as aggrecan, collagen type II, and Sox9 were expressed. ECM deposition was also detected by histological procedures. Collagen type II was present in the samples, as well as collagen type I. Despite no statistically significant values being obtained for gene expression, the other results support the choice of the bioreactor for this type of culture.

  17. Biomimetic growth of hydroxyapatite on phosphorylated electrospun cellulose nanofibers.

    Science.gov (United States)

    Li, Kaina; Wang, Jiangnan; Liu, Xinqing; Xiong, Xiaopeng; Liu, Haiqing

    2012-11-06

    In biomimicking the formation of collagen fiber/hydroxyapatite (HAp) in natural bone, electrospun cellulose nanofiber (CelluNF)/HAp composites were synthesized in simulated body fluid (SBF). Their morphology and structure were characterized by SEM, TEM, XRD and XPS. CelluNFs showed low bioactivity in inducing the growth of HAp. In order to improve this ability, CelluNFs were slightly phosphorylated with a degree of substitution of phosphate group of 0.28. The modified CelluNFs were highly effective in guiding the HAp growth along the fibers. The HAp crystal size in the composites was ca. 24 nm, and the lattice spacing of (211) plane was 2.83 Å. It was found that the HAps in the composites were calcium deficient. The CelluNF/HAp composites are highly porous materials with micro-, meso-, and macro-pores. A mechanism for the HAp growth on CelluNFs was presented. Such CelluNF/HAp composites can be potentially useful in the field of bone tissue engineering. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Electrospun carbon nanofiber modified electrodes for stripping voltammetry.

    Science.gov (United States)

    Zhao, Daoli; Wang, Tingting; Han, Daewoo; Rusinek, Cory; Steckl, Andrew J; Heineman, William R

    2015-09-15

    Electrospun polyacrylonitrile (PAN) based carbon nanofibers (CNFs) have attracted intense attention due to their easy processing, high carbon yield, and robust mechanical properties. In this work, a CNF modified glassy carbon (GC) electrode that was coated with Nafion polymer was evaluated as a new electrode material for the simultaneous determination of trace levels of heavy metal ions by anodic stripping voltammetry (ASV). Pb(2+) and Cd(2+) were used as a representative system for this initial study. Well-defined stripping voltammograms were obtained when Pb(2+) and Cd(2+) were determined individually and then simultaneously in a mixture. Compared to a bare GC electrode, the CNF/Nafion modified GC (CNF/Nafion/GC) electrode improved the sensitivity for lead detection by 8-fold. The interface properties of the CNF/Nafion/GC were characterized by electrochemical impedance spectroscopy (EIS), which showed the importance of the ratio of CNF/Nafion on electrode performance. Under optimized conditions, the detection limits are 0.9 and 1.5 nM for Pb(2+) and Cd(2+), respectively.

  19. Study on superhydrophobic surfaces of octanol grafted electrospun silica nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Long-Yue [Key Laboratory of Natural Resources of Changbai Mountain and Functional Molecules, Yanbian University, Yanji 133002 (China); Department of Chemical Engineering, College of Engineering, Yanbian University, 977 Gongyuan Road, Yanji 133002 (China); Han, Shunyu; Jiang, Nanzhe [Department of Chemical Engineering, College of Engineering, Yanbian University, 977 Gongyuan Road, Yanji 133002 (China); Meng, Wan, E-mail: mengw@ybu.edu.cn [Department of Chemical Engineering, College of Engineering, Yanbian University, 977 Gongyuan Road, Yanji 133002 (China)

    2014-12-15

    In this work, superhydrophobic surfaces were successfully prepared by grafting of octanol on the surface of electrospun silica nanofibers (SNFs). The chemical compositions and microstructures of the prepared SNFs surfaces were investigated by using N{sub 2} full isotherms, Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and contact angle measurements. The results indicate that the surface of SNFs changed from being superhydrophilic to superhydrophobic by octanol surface grafting. The contact angle of the octanol-grafted SNFs was close to 150.2° because their surface was modified by –(CH{sub 2}){sub 6}–CH{sub 3} groups. The 3D network of SNFs networks and the low surface energy of the alkyl side chains played important roles in creating the superhydrophobic surface of the SNFs. - Highlights: • Superhydrophobic surface was prepared from electrospinning SNFs and by grafting octanol on their surface. • The surface of SNFs changed from superhydrophilic to superhydrophobic. • The CA of MSNFs became 150.2° because of interactions between grafted octyl groups.

  20. Antimicrobial electrospun silver-, copper- and zinc-doped polyvinylpyrrolidone nanofibers.

    Science.gov (United States)

    Quirós, Jennifer; Borges, João P; Boltes, Karina; Rodea-Palomares, Ismael; Rosal, Roberto

    2015-12-15

    The use of electrospun polyvinylpyrrolidone (PVP) nanofibers containing silver, copper, and zinc nanoparticles was studied to prepare antimicrobial mats using silver and copper nitrates and zinc acetate as precursors. Silver became reduced during electrospinning and formed nanoparticles of several tens of nanometers. Silver nanoparticles and the insoluble forms of copper and zinc were dispersed using low molecular weight PVP as capping agent. High molecular weight PVP formed uniform fibers with a narrow distribution of diameters around 500 nm. The fibers were converted into an insoluble network using ultraviolet irradiation crosslinking. The efficiency of metal-loaded mats against the bacteria Escherichia coli and Staphylococcus aureus was tested for different metal loadings by measuring the inhibition of colony forming units and the staining with fluorescent probes for metabolic viability and compromised membranes. The assays included the culture in contact with mats and the direct staining of surface attached microorganisms. The results indicated a strong inhibition for silver-loaded fibers and the absence of significant amounts of viable but non-culturable microorganisms. Copper and zinc-loaded mats also decreased the metabolic activity and cell viability, although in a lesser extent. Metal-loaded fibers allowed the slow release of the soluble forms of the three metals. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Electrospun nanofiber membranes for adsorption of dye molecules from textile wastewater

    Science.gov (United States)

    Akduman, C.; Akçakoca Kumbasar, E. P.; Morsunbul, S.

    2017-10-01

    The nanofiber membranes prepared by the electrospinning method have unique properties such as high specific surface area and high porosity with fine pores. These properties led electrospun nanofiber membranes to use for the removal of dye molecules from textile wastewater. In this study, a hydrophobic Thermoplastic Polyurethane (TPU) and a hydrophilic Poly (vinyl alcohol) (PVA) were selected for producing electrospun nanofibers and their sorption capacities were investigated. The largest sorption capacity reached to maximum 88.31 mg/g, belong to BTCA cross-linked PVA membranes due to hydrophilic character of PVA. Contrary to expectation, hydrophobic character of TPU was dominant and incorporation of CD to the TPU nanofibers did not affect the sorption of the TPU membranes, and showed very low adsorption capacity (14.48 mg/g).

  2. Enhancing the Mechanical Properties of Electrospun Nanofiber Mats through Controllable Welding at the Cross Points.

    Science.gov (United States)

    Li, Haoxuan; Zhu, Chunlei; Xue, Jiajia; Ke, Qinfei; Xia, Younan

    2017-05-01

    This communication describes a simple and effective method for welding electrospun nanofibers at the cross points to enhance the mechanical properties of their nonwoven mats. The welding is achieved by placing a nonwoven mat of the nanofibers in a capped vial with the vapor of a proper solvent. For polycaprolactone (PCL) nanofibers, the solvent is dichloromethane (DCM). The welding can be managed in a controllable fashion by simply varying the partial pressure of DCM and/or the exposure time. Relative to the pristine nanofiber mat, the mechanical strength of the welded PCL nanofiber mat can be increased by as much as 200%. Meanwhile, such a treatment does not cause any major structural changes, including morphology, fiber diameter, and pore size. This study provides a generic method for improving the mechanical properties of nonwoven nanofiber mats, holding great potential in various applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Fabrication and Characterization of Electrospun Wool Keratin/Poly(vinyl alcohol Blend Nanofibers

    Directory of Open Access Journals (Sweden)

    Shuai Li

    2014-01-01

    Full Text Available Wool keratin/poly(vinyl alcohol (PVA blend nanofibers were fabricated using the electrospinning method in formic acid solutions with different weight ratios of keratin to PVA. The resultant blend nanofibers were characterized by scanning electron microscopy (SEM, Fourier transform infrared (FTIR, X-ray diffraction (XRD, thermal gravimetric analysis (TGA, and tensile test. SEM images showed that the diameter of the blend nanofibers was affected by the content of keratin in blend solution. FTIR and XRD analyses data demonstrated that there were good interactions between keratin and PVA in the blended nanofibers caused by possibly hydrogen bonds. The TGA study revealed that the thermal stability of the blend nanofibers was between those of keratin and PVA. Tensile test indicated that the addition of PVA was able to improve the mechanical properties of the electrospun nanofibers.

  4. High-Temperature Stable Anatase Titanium Oxide Nanofibers for Lithium-Ion Battery Anodes.

    Science.gov (United States)

    Lee, Sangkyu; Eom, Wonsik; Park, Hun; Han, Tae Hee

    2017-08-02

    Control of the crystal structure of electrochemically active materials is an important approach to fabricating high-performance electrodes for lithium-ion batteries (LIBs). Here, we report a methodology for controlling the crystal structure of TiO2 nanofibers by adding aluminum isopropoxide to a common sol-gel precursor solution utilized to create TiO2 nanofibers. The introduction of aluminum cations impedes the phase transformation of electrospun TiO2 nanofibers from the anatase to the rutile phase, which inevitably occurs in the typical annealing process utilized for the formation of TiO2 crystals. As a result, high-temperature stable anatase TiO2 nanofibers were created in which the crystal structure was well-maintained even at high annealing temperatures of up to 700 °C. Finally, the resulting anatase TiO2 nanofibers were utilized to prepare LIB anodes, and their electrochemical performance was compared to pristine TiO2 nanofibers that contain both anatase and rutile phases. Compared to the electrode prepared with pristine TiO2 nanofibers, the electrode prepared with anatase TiO2 nanofibers exhibited excellent electrochemical performances such as an initial Coulombic efficiency of 83.9%, a capacity retention of 89.5% after 100 cycles, and a rate capability of 48.5% at a current density of 10 C (1 C = 200 mA g-1).

  5. Design and Characterization of Electrospun Polyamide Nanofiber Media for Air Filtration Applications

    Directory of Open Access Journals (Sweden)

    Jonas Matulevicius

    2014-01-01

    Full Text Available Electrospun polyamide 6 (PA 6 and polyamide 6/6 (PA 6/6 nanofibers were produced in order to investigate their experimental characteristics with the goal of obtaining filtration relevant fiber media. The experimental design model of each PA nanofibers contained the following variables: polymer concentration, ratio of solvents, nanofiber media collection time, tip-to-collector distance, and the deposition voltage. The average diameter of the fibers, their morphology, basis weight, thickness, and resulting media solidity were investigated. Effects of each variable on the essential characteristics of PA 6/6 and PA 6 nanofiber media were studied. The comparative analysis of the obtained PA 6/6 and PA 6 nanofiber characteristics revealed that PA 6/6 had higher potential to be used in filtration applications. Based on the experimental results, the graphical representation—response surfaces—for obtaining nanofiber media with the desirable fiber diameter and basis weight characteristics were derived. Based on the modelling results the nanofiber filter media (mats were fabricated. Filtration results revealed that nanofiber filter media electrospun from PA6/6 8% (w/vol solutions with the smallest fiber diameters (62–66 nm had the highest filtration efficiency (PA6/6_30 = 84.9–90.9% and the highest quality factor (PA6/6_10 = 0.0486–0.0749 Pa−1.

  6. BiOCl nanosheets immobilized on electrospun polyacrylonitrile nanofibers with high photocatalytic activity and reusable property

    Energy Technology Data Exchange (ETDEWEB)

    Chou, Yuechen; Shao, Changlu, E-mail: clshao@nenu.edu.cn; Li, Xinghua, E-mail: lixh781@nenu.edu.cn; Su, Chunyan; Xu, Hongchuan; Zhang, Mingyi; Zhang, Peng; Zhang, Xin; Liu, Yichun

    2013-11-15

    One-dimensional BiOCl/PAN composite nanofibers which are composed of bismuth oxychloride (BiOCl) nanosheets on electrospun polyacrylonitrile (PAN) nanofibers were fabricated by combining electrospinning technique and solvothermal method. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction, UV–vis diffuse reflectance, Fourier transform infrared spectrum, X-ray photoelectron spectroscopy, thermal gravimetric and differential thermal analysis, were used to characterize the as-fabricated BiOCl/PAN composite nanofibers. The results revealed that BiOCl nanosheets were successfully immobilized on electrospun PAN nanofibers. The contents of the BiOCl nanosheets were controlled by adjusting the precursor concentrations for the fabrication of BiOCl/PAN composite nanofibers during the solvothermal synthesis processes. It was found that some interactions might exist between BiOCl and PAN molecules of BiOCl/PAN composite nanofibers. The obtained BiOCl/PAN composite nanofibers exhibited high photocatalytic activity for degradation of rhodamine B under ultraviolet light irradiation. The trapping experiments confirmed that the main active species for photocatalysis was hydroxyl radicals, which was produced by both the oxidative pathway and reductive pathway. Notably, the BiOCl/PAN composite nanofibers photocatalysts not only had good reusable property because of their one-dimensional structure and flexibility but also retained high photocatalytic stabilities after several cycles due to the interaction between BiOCl and PAN molecules.

  7. Oriented growth of rat Schwann cells on aligned electrospun poly(methyl methacrylate) nanofibers.

    Science.gov (United States)

    Xia, Haijian; Sun, Xiaochuan; Liu, Dan; Zhou, Yudong; Zhong, Dong

    2016-10-15

    Transplanted Schwann cells have the potential to serve as a support for regenerating neurites after spinal cord injury. However, implanted Schwann cells die off rapidly once transplanted partly owing to the absence of a proper matrix support, with a glia scar and a cavity being present instead at the injury site. For this report, we evaluated aligned electrospun poly(methyl methacrylate) nanofibers as a Schwann cell-loading scaffold in vitro. By monitoring the fluorescence of green fluorescence protein-containing Schwann cells cultured on nanofibers, we found that aligned nanofibers provided better support for the cells than did non-aligned nanofibers. The cells elongated along the long axes of the aligned nanofibers and formed longer cell processes than when the substrate was non-aligned nanofibers. By coculturing Schwann cells with dorsal root ganglion neurons, it was also found that Schwann cells and neurites of dorsal root ganglion neurons could share and both elongate along the orientation of aligned nanofibers and thus they had a higher chance of colocalization than cocultured on film and non-aligned fibers, which might be beneficial to the ensuring process of myelination. The results of the study indicate that aligned electrospun nanofibers may serve as a Schwann cell-loading scaffold for future implantation research. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Photocatalytic performance of Cu-doped TiO2 nanofibers treated by the hydrothermal synthesis and air-thermal treatment

    Science.gov (United States)

    Wu, Ming-Chung; Wu, Po-Yeh; Lin, Ting-Han; Lin, Tz-Feng

    2018-02-01

    Series of transition metal-doped TiO2 (metal/TiO2) is prepared by combining the hydrothermal synthesis and air-thermal treatment without any reduction process. The selected transition metal precursors, including Ag, Au, Co, Cr, Cu, Fe, Ni, Pd, Pt, Y, and Zn, were individually doped into TiO2 nanofibers to evaluate the photocatalytic degradation activity and photocatalytic hydrogen generation. Consider the photocatalytic performance of these synthesized metal/TiO2 under UV-A irradiation, copper doped TiO2 nanofibers (Cu/TiO2 NFs) was chosen for further study due to its extraordinary reactivity. Systematical studies were spread to optimize the doping concentration and the calcination condition for much higher photocatalytic activity Cu/TiO2 NFs. In the photocatalytic degradation test, 0.5 mol%-Cu/TiO2 NFs calcined at 650 °C exhibits the highest activity, which is even higher than commercial TiO2-AEROXIDE® TiO2 P25 under UV-A irradiation. The synthesized 0.5 mol%-Cu/TiO2-650 NFs also have the capability in the photocatalytic hydrogen production. The hydrogen evolution rates are 200 μmol/g·h under UV-A irradiation and 280 μmol/g·h under UV-B irradiation. The density of state calculated by CASTEP for Cu/TiO2 indicates that Cu doping contributes to the states near valence band edge and narrows the band gap. The disclosed process in this study is industrial safe, convenient and cost-effective. We further produce a significant amount of TiO2-based catalysts without any hydrogen reduction treatment.

  9. Coaxial electrospun polyurethane core-shell nanofibers for shape memory and antibacterial nanomaterials

    Directory of Open Access Journals (Sweden)

    2011-02-01

    Full Text Available A novel kind of shape memory polyurethane (SMPU nanofibers with core-shell nanostructure is fabricated using coaxial electrospinning. Transmission electron microscopy (TEM and scanning electron microscopy (SEM results show that nanofibers with core-shell structure or bead-on-string structure can be electrospun successfully from the core solution of polycaprolactone based SMPU (CLSMPU and shell solution of pyridine containing polyurethane (PySMPU. In addition to the excellent shape memory effect with good shape fixity, excellent antibacterial activity against both gramnegative bacteria and gram-positive bacteria are achieved in the CLSMPU-PySMPU core-shell nanofiber. Finally, it is proposed that the antibacterial mechanism should be resulted from the PySMPU shell materials containing amido group in γ position and the high surface area per unit mass of nanofibers. Thus, the CLSMPU-PySMPU core shell nanofibers can be used as both shape memory nanomaterials and antibacterial nanomaterials.

  10. Load bearing enhancement of pin joined composite laminates using electrospun polyacrylonitrile nanofiber mats

    Directory of Open Access Journals (Sweden)

    J. Herwan

    2016-03-01

    Full Text Available Polyacrylonitrile (PAN nanofibers were produced by an electrospinning technique and directly deposited onto carbon fabric to improve the load bearing strength of pin joined composite laminates. Two types of specimens, virgin laminates and nano-modified laminates, were prepared. A modified carbon fiber reinforced polymer (CFRP laminate was fabricated by interleaving electrospun nanofibers at all of the interlayers of an eight-ply woven carbon fiber fabric. The load bearing test results of the pin joined laminates indicated the electrospun PAN nanofibers increased the load bearing strength by 18.9%. In addition, three point bending tests were also conducted to investigate the flexural modulus and flexural strength of both types of laminates. The flexural modulus and flexural strength also increased by 20.9% and 55.91%, respectively.

  11. All-textile flexible supercapacitors using electrospun poly(3,4-ethylenedioxythiophene) nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Laforgue, Alexis [Functional Polymer Systems Group, Industrial Materials Institute, National Research Council Canada, 75, de Mortagne Blvd, Boucherville, Quebec J4B 6Y4 (Canada)

    2011-01-01

    Poly(3,4-ethylenedioxythiophene) (PEDOT) nanofibers were obtained by the combination of electrospinning and vapor-phase polymerization. The fibers had diameters around 350 nm, and were soldered at most intersections, providing a strong dimensional stability to the mats. The nanofiber mats demonstrated very high conductivity (60 {+-} 10 S cm{sup -1}, the highest value reported so far for polymer nanofibers) as well as improved electrochemical properties, due to the ultraporous nature of the electrospun mats. The mats were incorporated into all-textile flexible supercapacitors, using carbon cloths as the current collectors and electrospun polyacrylonitrile (PAN) nanofibrous membranes as the separator. The textile layers were stacked and embedded in a solid electrolyte containing an ionic liquid and PVDF-co-HFP as the host polymer. The resulting supercapacitors were totally flexible and demonstrated interesting and stable performances in ambient conditions. (author)

  12. Towards Scalable Binderless Electrodes: Carbon Coated Silicon Nanofiber Paper via Mg Reduction of Electrospun SiO2 Nanofibers

    OpenAIRE

    Favors, Zachary; Bay, Hamed Hosseini; Mutlu, Zafer; Ahmed, Kazi; Ionescu, Robert; Ye, Rachel; Ozkan, Mihrimah; Ozkan, Cengiz S.

    2015-01-01

    The need for more energy dense and scalable Li-ion battery electrodes has become increasingly pressing with the ushering in of more powerful portable electronics and electric vehicles (EVs) requiring substantially longer range capabilities. Herein, we report on the first synthesis of nano-silicon paper electrodes synthesized via magnesiothermic reduction of electrospun SiO2 nanofiber paper produced by an in situ acid catalyzed polymerization of tetraethyl orthosilicate (TEOS) in-flight. Free-...

  13. Removal of a Cationic Dye by Adsorption/Photodegradation Using Electrospun PAN/O-MMT Composite Nanofibrous Membranes Coated with TiO2

    Directory of Open Access Journals (Sweden)

    Qingqing Wang

    2012-01-01

    Full Text Available Polyacrylonitrile (PAN/organic-modified montmorillonite (O-MMT composite nanofibrous membranes were firstly prepared by electrospinning and then coated with titanium dioxide (TiO2 using spin coating technique. The structural morphology of the nanofibrous membranes with different mass ratio of O-MMT before and after spin coating was investigated by scanning electron microscope (SEM and transmission electron microscope (TEM. The chemical property of adsorbed methylene blue (MB was analyzed by infrared spectroscopy (IR. The adsorption and photodegradation capability of the TiO2-coated PAN/O-MMT composite nanofibrous membranes were evaluated by adsorption rate of MB and K/S values of the membranes before and after UV irradiation. The experimental results indicated that with the increase of O-MMT amount, the diameters of the nanofibers decreased and the adsorption rate of MB was evidently improved. Besides, with the increase of TiO2 film layers, the photocatalytic properties were enhanced while the adsorption process was slowed down.

  14. Double emulsion electrospun nanofibers as a growth factor delivery vehicle for salivary gland regeneration

    Science.gov (United States)

    Foraida, Zahraa I.; Sharikova, Anna; Peerzada, Lubna N.; Khmaladze, Alexander; Larsen, Melinda; Castracane, James

    2017-08-01

    Sustained delivery of growth factors, proteins, drugs and other biologically active molecules is necessary for tissue engineering applications. Electrospun fibers are attractive tissue engineering scaffolds as they partially mimic the topography of the extracellular matrix (ECM). However, they do not provide continuous nourishment to the tissue. In search of a biomimetic scaffold for salivary gland tissue regeneration, we previously developed a blend nanofiber scaffold composed of the protein elastin and the synthetic polymer polylactic-co-glycolic acid (PLGA). The nanofiber scaffold promoted in vivo-like salivary epithelial cell tissue organization and apicobasal polarization. However, in order to enhance the salivary cell proliferation and biomimetic character of the scaffold, sustained growth factor delivery is needed. The composite nanofiber scaffold was optimized to act as a growth factor delivery system using epidermal growth factor (EGF) as a model protein. The nanofiber/EGF hybrid nanofibers were synthesized by double emulsion electrospinning where EGF is emulsified within a water/oil/water (w/o/w) double emulsion system. Successful incorporation of EGF was confirmed using Raman spectroscopy. EGF release profile was characterized using enzyme-linked immunosorbent assay (ELIZA) of the EGF content. Double emulsion electrospinning resulted in slower release of EGF. We demonstrated the potential of the proposed double emulsion electrospun nanofiber scaffold for the delivery of growth factors and/or drugs for tissue engineering and pharmaceutical applications.

  15. A Novel Exploration of a Combination of Gambogic Acid with TiO2 Nanofibers: The Photodynamic Effect for HepG2 Cell Proliferation

    Directory of Open Access Journals (Sweden)

    Jingyuan Li

    2014-09-01

    Full Text Available As a good photosensitizer, TiO2 nanomaterials show potential biomedical applications, such as drug carriers or enhancers in photodynamic therapy. In this contribution, novel nanocomposites through the blending of TiO2 nanofibers with the active compound, gambogic acid (GA, were explored, and the results showed that GA could inhibit cancer cell proliferation in a time-dependent and dose-dependent manner, inducing apoptosis and cell cycle arrest at the G0/G1 phase in HepG2 cells. It is evident that after the GA-TiO2 nanocomposites were cultured with the cancer cells, the cooperation effect could effectively enhance the cytotoxicity of GA for HepG2 cells. Meanwhile, if activated by UV irradiation, under the presence of GA-TiO2 nanocomposites, this would lead to significant apoptosis and necrosis for HepG2 cells with a photodynamic therapy (PDT effect. Associated with the controlled drug-release from these nanocomposites, TiO2 nanofibers could readily cut down the drug consumption in HepG2 cells and reduce the side-effect for the normal cells and tissue, which may be further utilized in the therapeutic alliance for cancer therapy.

  16. Graphene oxide decorated electrospun gelatin nanofibers: Fabrication, properties and applications.

    Science.gov (United States)

    Jalaja, K; Sreehari, V S; Kumar, P R Anil; Nirmala, R James

    2016-07-01

    Gelatin nanofiber fabricated by electrospinning process is found to mimic the complex structural and functional properties of natural extracellular matrix for tissue regeneration. In order to improve the physico-chemical and biological properties of the nanofibers, graphene oxide is incorporated in the gelatin to form graphene oxide decorated gelatin nanofibers. The current research effort is focussed on the fabrication and evaluation of physico-chemical and biological properties of graphene oxide-gelatin composite nanofibers. The presence of graphene oxide in the nanofibers was established by transmission electron microscopy (TEM). We report the effect of incorporation of graphene oxide on the mechanical, thermal and biological performance of the gelatin nanofibers. The tensile strength of gelatin nanofibers was increased from 8.29±0.53MPa to 21±2.03MPa after the incorporation of GO. In order to improve the water resistance of nanofibers, natural based cross-linking agent, namely, dextran aldehyde was employed. The cross-linked composite nanofibers showed further increase in the tensile strength up to 56.4±2.03MPa. Graphene oxide incorporated gelatin nanofibers are evaluated for bacterial activity against gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria and cyto compatibility using mouse fibroblast cells (L-929 cells). The results indicate that the graphene oxide incorporated gelatin nanofibers do not prevent bacterial growth, nevertheless support the L-929 cell adhesion and proliferation. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Mechanical properties and cellular response of novel electrospun nanofibers for ligament tissue engineering: Effects of orientation and geometry.

    Science.gov (United States)

    Pauly, Hannah M; Kelly, Daniel J; Popat, Ketul C; Trujillo, Nathan A; Dunne, Nicholas J; McCarthy, Helen O; Haut Donahue, Tammy L

    2016-08-01

    Electrospun nanofibers are a promising material for ligamentous tissue engineering, however weak mechanical properties of fibers to date have limited their clinical usage. The goal of this work was to modify electrospun nanofibers to create a robust structure that mimics the complex hierarchy of native tendons and ligaments. The scaffolds that were fabricated in this study consisted of either random or aligned nanofibers in flat sheets or rolled nanofiber bundles that mimic the size scale of fascicle units in primarily tensile load bearing soft musculoskeletal tissues. Altering nanofiber orientation and geometry significantly affected mechanical properties; most notably aligned nanofiber sheets had the greatest modulus; 125% higher than that of random nanofiber sheets; and 45% higher than aligned nanofiber bundles. Modifying aligned nanofiber sheets to form aligned nanofiber bundles also resulted in approximately 107% higher yield stresses and 140% higher yield strains. The mechanical properties of aligned nanofiber bundles were in the range of the mechanical properties of the native ACL: modulus=158±32MPa, yield stress=57±23MPa and yield strain=0.38±0.08. Adipose derived stem cells cultured on all surfaces remained viable and proliferated extensively over a 7 day culture period and cells elongated on nanofiber bundles. The results of the study suggest that aligned nanofiber bundles may be useful for ligament and tendon tissue engineering based on their mechanical properties and ability to support cell adhesion, proliferation, and elongation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. In vitro characterization of magnetic electrospun IDA-grafted chitosan nanofiber composite for hyperthermic tumor cell treatment.

    Science.gov (United States)

    Lin, Ta-Chun; Lin, Feng-Huei; Lin, Jui-Che

    2013-01-01

    Magnetic nanoparticles were the thermoseeds under an alternating magnetic field and can be used to produce highly localized hyperthermia effect on deep-seated tumor. Nevertheless, effective and precisive delivery of nanoparticles to the treatment-intended site remains a challenge. In this study, Fe3O4 nanoparticles were incorporated onto the crosslinked electrospun chitosan nanofibers using chemical co-precipitation from the Fe ions adsorbed. Such magnetic nanoparticle-nanofiber composites could be delivered to the treatment site precisely by surgical or endoscopic method. Iminodiacetic acid (IDA) functionality was grafted onto the chitosan with an aim to increase the amount of magnetic nanoparticles formed in the electrospun magnetic nanofiber composite. The morphology, crystalline phase as well as the magnetism characteristic of the magnetic electrospun nanofiber matrixes, was analyzed. Results have indicated that, with the incorporation of IDA functionality, more magnetic nanoparticles were formed in the electrospun chitosan nanofiber matrix. In addition, the magnetic IDA-grafted chitosan nanofiber composite can effectively reduced the tumor cell proliferation under the application of magnetic field. This finding suggested the magnetic electrospun chitosan nanofiber composite can be of potential for hyperthermia treatment.

  19. Graphene oxide decorated electrospun gelatin nanofibers: Fabrication, properties and applications

    Energy Technology Data Exchange (ETDEWEB)

    Jalaja, K. [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram, Kerala 695 547 (India); Sreehari, V.S. [Indian Institute of Science Education and Research Bhopal, Bhauri, Madhya Pradesh 462066 (India); Kumar, P.R. Anil [Tissue culture laboratory, Biomedical Technology Wing, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Poojappura, Thiruvananthapuram, Kerala 695 012 (India); Nirmala, R. James, E-mail: nirmala@iist.ac.in [Department of Chemistry, Indian Institute of Space Science and Technology, Valiamala, Thiruvananthapuram, Kerala 695 547 (India)

    2016-07-01

    Gelatin nanofiber fabricated by electrospinning process is found to mimic the complex structural and functional properties of natural extracellular matrix for tissue regeneration. In order to improve the physico-chemical and biological properties of the nanofibers, graphene oxide is incorporated in the gelatin to form graphene oxide decorated gelatin nanofibers. The current research effort is focussed on the fabrication and evaluation of physico-chemical and biological properties of graphene oxide-gelatin composite nanofibers. The presence of graphene oxide in the nanofibers was established by transmission electron microscopy (TEM). We report the effect of incorporation of graphene oxide on the mechanical, thermal and biological performance of the gelatin nanofibers. The tensile strength of gelatin nanofibers was increased from 8.29 ± 0.53 MPa to 21 ± 2.03 MPa after the incorporation of GO. In order to improve the water resistance of nanofibers, natural based cross-linking agent, namely, dextran aldehyde was employed. The cross-linked composite nanofibers showed further increase in the tensile strength up to 56.4 ± 2.03 MPa. Graphene oxide incorporated gelatin nanofibers are evaluated for bacterial activity against gram positive (Staphylococcus aureus) and gram negative (Escherichia coli) bacteria and cyto compatibility using mouse fibroblast cells (L-929 cells). The results indicate that the graphene oxide incorporated gelatin nanofibers do not prevent bacterial growth, nevertheless support the L-929 cell adhesion and proliferation. - Highlights: • Graphene oxide nano reinforced gelatin nanofibers are fabricated by electrospinning. • Graphene oxide (0.5%) loading resulted in increased tensile strength. • GO/gelatin nanofibers are cross-linked with dextran aldehyde. • Composite nanofibers favoured adhesion of L-929 cells. • GO/gelatin mats do not prevent bacterial growth.

  20. Assessment of Morphology, Activity, and Infiltration of Astrocytes on Marine EPS-Imbedded Electrospun PCL Nanofiber

    Directory of Open Access Journals (Sweden)

    Seul Ki Min

    2014-01-01

    Full Text Available Tissue engineering using a biomaterial including bioactive compounds has been researched as a way to restore injured neural systems. Extracellular polymeric substances (EPS extracted from marine seaweeds have been known to produce positive effects on physiological activities in human tissues. In this study, an electrospun nanofiber containing brown seaweed EPS was proven to be a candidate biomaterial for neural tissue engineering. Glial fibrillary acidic protein (GFAP as a specific marker protein increased in the astrocytes cultured on the polycaprolactone (PCL nanofiber containing EPS (EPS-PCL nanofiber, compared with PCL nanofiber. The upregulation of GFAP indicates that the EPS-PCL nanofiber induced astrocyte activation, which supports physiological agents favorable to restore injured neural tissue. Astrocytes could infiltrate into the EPS-PCL nanofiber mat without toxicity, comparable to PCL nanofiber. These results imply that EPS-PCL nanofiber could be a useful biomaterial to regulate astrocyte activity at a molecular level and could be considered as a novel therapeutic material for neural tissue engineering.

  1. Electrospun polyacrylonitrile nanofibers loaded with silver nanoparticles by silver mirror reaction

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yongzheng; Li, Yajing; Zhang, Jianfeng; Yu, Zhongzhen; Yang, Dongzhi, E-mail: yangdz@mail.buct.edu.cn

    2015-06-01

    The silver mirror reaction (SMR) method was selected in this paper to modify electrospun polyacrylonitrile (PAN) nanofibers, and these nanofibers loaded with silver nanoparticles showed excellent antibacterial properties. PAN nanofibers were first pretreated in AgNO{sub 3} aqueous solution before the SMR process so that the silver nanoparticles were distributed evenly on the outer surface of the nanofibers. The final PAN nanofibers were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), transmission electron microscopy (TEM), TEM-selected area electron diffraction (SAED), X-ray diffraction (XRD) and thermogravimetric analysis (TGA). SEM, TEM micrographs and SAED patterns confirmed homogeneous dispersion of the silver nanoparticles which were composed of monocrystals with diameters 20–30 nm. EDS and XRD results showed that these monocrystals tended to form face-centered cubic single silver. TGA test indicated that the nanoparticles loaded on the nanofibers reached above 50 wt.%. This material was also evaluated by the viable cell-counting method. The results indicated that PAN nanofibers loaded with silver nanoparticles exhibited excellent antimicrobial activities against gram-negative Escherichia coli (E. coli), gram-positive Staphylococcus aureus (S. aureus) and the fungus Monilia albicans. Thus, this material had many potential applications in biomedical fields. - Highlights: • Silver mirror reaction was used to prepare nanofibers loaded with silver nanoparticles. • The SAED patterns demonstrated the monocrystallinity of silver nanocrystals. • The XRD results showed nanoparticles tended to be face-centered cubic single silver. • The material showed excellent antimicrobial activities against bacteria and fungi.

  2. Effects of Electrode Reversal on the Distribution of Naproxen in the Electrospun Cellulose Acetate Nanofibers

    Directory of Open Access Journals (Sweden)

    Zhuang Li

    2014-01-01

    Full Text Available Naproxen (NAP/cellulose acetate hybrid nanofibers were prepared by positive and reversed emitting electrodes electrospinning setups. The morphology and structure of the resultant nanofibers were characterized, and the NAP release behaviors were investigated. It was found that NAP dispersed in the CA matrix in molecular level, and no aggregation and dimers of NAP were found in the resultant NAP/CA hybrid nanofibers due to the formation of hydrogen bonds between NAP and CA. The nanofibers obtained by reversed emitting electrode electrospinning setup have a thicker diameter and a faster NAP release rate compared with those obtained by positive emitting electrode electrospinning setup. The faster drug release of NAP from nanofibers prepared by reversed emitting electrode electrospinning is due to the fact that the concentration of NAP molecules near the surface of the nanofibers is relatively higher than that of the nanofibers prepared by positive emitting electrode electrospinning setup. The effects of the electrode polarity on the distribution of drugs in nanofibers can be used to prepare hybrid electrospun fibers of different drug release rates, which may found applications in biomedical materials.

  3. Sterilization of Escherichia coli by using near-UV LED and TiO2 nanofibers that were prepared by using electrostatic spray

    Science.gov (United States)

    Lee, Dong-Gil; Hong, Ji-Tae; Son, Min-Kyu; Lee, Kyoung-Jun; Xu, Guo-Cheng; Prabakar, Kandasamy; Kim, Hee-je

    2010-05-01

    TiO2 nanofiber films were prepared by a homemade electrostatic spray method at 13 kV using a high power supply. As-prepared TiO2 was used to sterilize enteropathogenic Escherichia coli in polluted water by using near-UV LEDs at three different wavelengths with variable exposure time and frequency of irradiation. Irrespective of the wavelength of the light source used, longer irradiation times such as 1 h completely inactivated the E. coli. However, a wavelength of 375 nm was effective in inactivating in a shorter irradiation time (15 min). When the frequency of irradiation was 1 kHz, almost 95% of the E. coli was inactivated after 30 min exposure.

  4. Inactivated Sendai Virus (HVJ-E Immobilized Electrospun Nanofiber for Cancer Therapy

    Directory of Open Access Journals (Sweden)

    Takaharu Okada

    2015-12-01

    Full Text Available Inactivated Hemagglutinating Virus of Japan Envelope (HVJ-E was immobilized on electrospun nanofibers of poly(ε-caprolactone by layer-by-layer (LbL assembly technique. The precursor LbL film was first constructed with poly-L-lysine and alginic acid via electrostatic interaction. Then the HVJ-E particles were immobilized on the cationic PLL outermost surface. The HVJ-E adsorption was confirmed by surface wettability test, scanning laser microscopy, scanning electron microscopy, and confocal laser microscopy. The immobilized HVJ-E particles were released from the nanofibers under physiological condition. In vitro cytotoxic assay demonstrated that the released HVJ-E from nanofibers induced cancer cell deaths. This surface immobilization technique is possible to perform on anti-cancer drug incorporated nanofibers that enables the fibers to show chemotherapy and immunotherapy simultaneously for an effective eradication of tumor cells in vivo.

  5. Polypyrrole-Coated Electrospun PLGA Nanofibers for Neural Tissue Applications

    OpenAIRE

    Lee, Jae Young; Bashur, Chris A.; Goldstein, Aaron S.; Christine E Schmidt

    2009-01-01

    Electrospinning is a promising approach to create nanofiber structures that are capable of supporting adhesion and guiding extension of neurons for nerve regeneration. Concurrently, electrical stimulation of neurons in the absence of topographical features also has been shown to guide axonal extension. Therefore, the goal of this study was to form electrically conductive nanofiber structures and to examine the combined effect of nanofiber structures and electrical stimulation. Conductive mesh...

  6. Application of a biotin functionalized QD assay for determining available binding sites on electrospun nanofiber membrane

    Directory of Open Access Journals (Sweden)

    Magnone Joshua

    2011-10-01

    Full Text Available Abstract Background The quantification of surface groups attached to non-woven fibers is an important step in developing nanofiber biosensing detection technologies. A method utilizing biotin functionalized quantum dots (QDs 655 for quantitative analysis of available biotin binding sites within avidin immobilized on electrospun nanofiber membranes was developed. Results A method for quantifying nanofiber bound avidin using biotin functionalized QDs is presented. Avidin was covalently bound to electrospun fibrous polyvinyl chloride (PVC 1.8% COOH w/w containing 10% w/w carbon black membranes using primary amine reactive EDC-Sulfo NHS linkage chemistry. After a 12 h exposure of the avidin coated membranes to the biotin-QD complex, fluorescence intensity was measured and the total amount of attached QDs was determined from a standard curve of QD in solution (total fluorescence vs. femtomole of QD 655. Additionally, fluorescence confocal microscopy verified the labeling of avidin coated nanofibers with QDs. The developed method was tested against 2.4, 5.2, 7.3 and 13.7 mg spray weights of electrospun nanofiber mats. Of the spray weight samples tested, maximum fluorescence was measured for a weight of 7.3 mg, not at the highest weight of 13.7 mg. The data of total fluorescence from QDs bound to immobilized avidin on increasing weights of nanofiber membrane was best fit with a second order polynomial equation (R2 = .9973 while the standard curve of total fluorescence vs. femtomole QDs in solution had a linear response (R2 = .999. Conclusion A QD assay was developed in this study that provides a direct method for quantifying ligand attachment sites of avidin covalently bound to surfaces. The strong fluorescence signal that is a fundamental characteristic of QDs allows for the measurement of small changes in the amount of these particles in solution or attached to surfaces.

  7. Highly conductive quasi-coaxial electrospun quaternized polyvinyl alcohol nanofibers and composite as high-performance solid electrolytes

    Science.gov (United States)

    Liao, Guan-Ming; Li, Pin-Chieh; Lin, Jia-Shiun; Ma, Wei-Ting; Yu, Bor-Chern; Li, Hsieh-Yu; Liu, Ying-Ling; Yang, Chun-Chen; Shih, Chao-Ming; Lue, Shingjiang Jessie

    2016-02-01

    Electrospun quaternized polyvinyl alcohol (Q-PVA) nanofibers are prepared, and a potassium hydroxide (KOH)-doped nanofiber mat demonstrates enhanced ionic conductivity compared with a dense Q-PVA film with KOH doping. The Q-PVA composite containing 5.98% electrospun Q-PVA nanofibers exhibits suppressed methanol permeability. Both the high conductivity and suppressed methanol permeability are attributed to the quasi-coaxial structure of the electrospun nanofibers. The core of the fibers exhibits a more amorphous region that forms highly conductive paths, while the outer shell of the nanofibers contains more polymer crystals that serve as a hard sheath surrounding the soft core. This shell induces mass transfer resistance and creates a tortuous fuel pathway that suppresses methanol permeation. Such a Q-PVA composite is an effective solid electrolyte that makes the use of alkaline fuel cells viable. In a direct methanol alkaline fuel cell operated at 60 °C, a peak power density of 54 mW cm-2 is obtained using the electrospun Q-PVA composite, a 36.4% increase compared with a cell employing a pristine Q-PVA film. These results demonstrate that highly conductive coaxial electrospun nanofibers can be prepared through a single-opening spinneret and provide a possible approach for high-performance electrolyte fabrication.

  8. Electrospun Nanofibers of Guar Galactomannan for Targeted Drug Delivery

    Science.gov (United States)

    Chu, Hsiao Mei Annie

    2011-12-01

    Guar galactomannan is a biodegradable polysaccharide used widely in the food industry but also in the cosmetics, pharmaceutical, oil drilling, textile and paper industries. Guar consists of a mannose backbone and galactose side groups that are both susceptible to enzyme degradation, a unique property that can be explored for targeted drug delivery especially since those enzymes are naturally secreted by the microflora in human colon. The present study can be divided into three parts. In the first part, we discuss ways to modify guar to produce nanofibers by electrospinning, a process that involves the application of an electric field to a polymer solution or melt to facilitate production of fibers in the sub-micron range. Nanofibers are currently being explored as the next generation of drug carriers due to its many advantages, none more important than the fact that nanofibers are on a size scale that is a fraction of a hair's width and have large surface-to-volume ratio. The incorporation and controlled release of nano-sized drugs is one way in which nanofibers are being utilized in drug delivery. In the second part of the study, we explore various methods to crosslink guar nanofibers as a means to promote water-resistance in a potential drug carrier. The scope and utility of water-resistant guar nanofibers can only be fully appreciated when subsequent drug release studies are carried out. To that end, the third part of our study focuses on understanding the kinetics and diffusion mechanisms of a model drug, Rhodamine B, through moderately-swelling (crosslinked) hydrogel nanofibers in comparison to rapidly-swelling (non-crosslinked) nanofibers. Along the way, our investigations led us to a novel electrospinning set-up that has a unique collector designed to capture aligned nanofibers. These aligned nanofiber bundles can then be twisted to hold them together like yarn. From a practical standpoint, these yarns are advantageous because they come freely suspended and

  9. Composite 3D printed scaffold with structured electrospun nanofibers promotes chondrocyte adhesion and infiltration.

    Science.gov (United States)

    Rampichová, M; Košt'áková Kuželová, E; Filová, E; Chvojka, J; Šafka, J; Pelcl, M; Daňková, J; Prosecká, E; Buzgo, M; Plencner, M; Lukáš, D; Amler, E

    2017-11-13

    Additive manufacturing, also called 3D printing, is an effective method for preparing scaffolds with defined structure and porosity. The disadvantage of the technique is the excessive smoothness of the printed fibers, which does not support cell adhesion. In the present study, a 3D printed scaffold was combined with electrospun classic or structured nanofibers to promote cell adhesion. Structured nanofibers were used to improve the infiltration of cells into the scaffold. Electrospun layers were connected to 3D printed fibers by gluing, thus enabling the fabrication of scaffolds with unlimited thickness. The composite 3D printed/nanofibrous scaffolds were seeded with primary chondrocytes and tested in vitro for cell adhesion, proliferation and differentiation. The experiment showed excellent cell infiltration, viability, and good cell proliferation. On the other hand, partial chondrocyte dedifferentiation was shown. Other materials supporting chondrogenic differentiation will be investigated in future studies.

  10. Oxolane-2,5-dione modified electrospun cellulose nanofibers for heavy metals adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Stephen, Musyoka [University of Kwazulu-Natal, Private Bag X54001, Westville Durban 4000 (South Africa); Catherine, Ngila, E-mail: jcngila2002@yahoo.com [University of Kwazulu-Natal, Private Bag X54001, Westville Durban 4000 (South Africa); University of Johannesburg, Department of Chemical Technology, P.O Box 17011, Doornfontein 2028, Johannesburg (South Africa); Brenda, Moodley; Andrew, Kindness [University of Kwazulu-Natal, Private Bag X54001, Westville Durban 4000 (South Africa); Leslie, Petrik [Environmental and NanoScience Lab, Department of Chemistry, Faculty of Science, University of Western Cape, Private Bag X17, Bellville 7535 (South Africa); Corrine, Greyling [Cape Organic Chemical Optimization (Pty) Ltd 9 Avenue de Mist, Claremont 7708 (South Africa)

    2011-08-30

    Highlights: {yields} Electrospun and modified cellulose nanofibers have high surface area. {yields} Modified nanofibers showed improved adsorption of Cd and Pb from water. {yields} Regenerated modified nanofibers had high adsorption capacity hence recyclable. - Abstract: Functionalized cellulose nanofibers have been obtained through electrospinning and modification with oxolane-2,5-dione. The application of the nanofibers for adsorption of cadmium and lead ions from model wastewater samples is presented for the first time. Physical and chemical properties of the nanofibers were characterized. Surface chemistry during preparation and functionalization was monitored using Fourier transform-infrared spectroscopy, scanning electron microscopy, carbon-13 solid state nuclear magnetic resonance spectroscopy and Brunauer Emmett and Teller. Enhanced surface area of 13.68 m{sup 2} g{sup -1} was recorded for the nanofibers as compared to the cellulose fibers with a surface area of 3.22 m{sup 2} g{sup -1}. Freundlich isotherm was found to describe the interactions better than Langmuir: K{sub f} = 1.0 and 2.91 mmol g{sup -1} (r{sup 2} = 0.997 and 0.988) for lead and cadmium, respectively. Regenerability of the fiber mats was investigated and the results obtained indicate sustainability in adsorption efficacy of the material.

  11. Electrospun polyacrylonitrile nanofibers functionalized with EDTA for adsorption of ionic dyes

    Science.gov (United States)

    Chaúque, Eutilério F. C.; Dlamini, Langelihle N.; Adelodun, Adedeji A.; Greyling, Corinne J.; Ngila, J. Catherine

    2017-08-01

    The manipulation of nanofibers' surface chemistry could enhance their potential application toward the removal of ionic dyes in wastewater. For this purpose, surface modification of electrospun polyacrylonitrile (PAN) nanofibers with ethylenediaminetetraacetic acid (EDTA) and ethylenediamine (EDA) crosslinker was experimented. The functionalized EDTA-EDA-PAN nanofibers were characterized using Fourier transform infrared (FT-IR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) technique. The impregnation of EDA and EDTA chelating agents on the surface of PAN changed the distribution of nanofibers as proximity is increased (accompanied by reduced softness), but the nanofibrous structure of the pristine PAN nanofibers was not substantially altered. Adsorption equilibrium studies were performed with Freundlich, Langmuir and Temkin isotherm models with the former providing better correlation to the experimental data. The modified PAN nanofibers showed efficient sorption of methyl orange (MO) and reactive red (RR) from aqueous synthetic samples, evinced by the maximum adsorption capacities (at 25 °C) of 99.15 and 110.0 mg g-1, respectively. The fabricated nanofibers showed appreciable removal efficiency of the target dye sorptives from wastewater. However, the presence of high metal ions content affected the overall extraction of dyes from wastewater due to the depletion of the adsorbent's active adsorptive sites.

  12. Electrochromic device based on electrospun WO{sub 3} nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Dulgerbaki, Cigdem; Maslakci, Neslihan Nohut; Komur, Ali Ihsan; Oksuz, Aysegul Uygun, E-mail: ayseguluygun@sdu.edu.tr

    2015-12-15

    Highlights: • WO{sub 3} electrochromic nanofibers were prepared by electrospinning technique. • WO{sub 3} nanofibers switched reversibly from transparent to blue color. • Electrochromic device was assembled using ionic liquid based gel electrolyte. • Significant optical modulation and excellent cycling stability were achieved for ECD. - Abstract: The tungsten oxide (WO{sub 3}) nanofibers were grown directly onto an ITO-coated glass via an electrospinning method for electrochromic applications. The electrochromic properties of WO{sub 3} nanofibers were investigated in the presence of different electrolytes including a series of ionic liquids and classic LiClO{sub 4}-PC system. A significant optical modulation of 20.82% at 760 nm, reversible coloration with efficiency of 64.58 cm{sup 2}/C and excellent cycling stability were achieved for the nanofiber electrochromic device (ECD) with ionic liquid based gel electrolyte.

  13. Mechanically-reinforced electrospun composite silk fibroin nanofibers containing hydroxyapatite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyunryung [School of Mechanical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Che, Lihua; Ha, Yoon [Department of Neurosurgery, College of Medicine, Yonsei University, Seoul 120-749 (Korea, Republic of); Ryu, WonHyoung, E-mail: whryu@yonsei.ac.kr [School of Mechanical Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2014-07-01

    Electrospun silk fibroin (SF) scaffolds provide large surface area, high porosity, and interconnection for cell adhesion and proliferation and they may replace collagen for many tissue engineering applications. Despite such advantages, electrospun SF scaffolds are still limited as bone tissue replacement due to their low mechanical strengths. While enhancement of mechanical strengths by incorporating inorganic ceramics into polymers has been demonstrated, electrospinning of a mixture of SF and inorganic ceramics such as hydroxyapatite is challenging and less studied due to the aggregation of ceramic particles within SF. In this study, we aimed to enhance the mechanical properties of electrospun SF scaffolds by uniformly dispersing hydroxyapatite (HAp) nanoparticles within SF nanofibers. HAp nanoaprticles were modified by γ-glycidoxypropyltrimethoxysilane (GPTMS) for uniform dispersion and enhanced interfacial bonding between HAp and SF fibers. Optimal conditions for electrospinning of SF and GPTMS-modified HAp nanoparticles were identified to achieve beadless nanofibers without any aggregation of HAp nanoparticles. The MTT and SEM analysis of the osteoblasts-cultured scaffolds confirmed the biocompatibility of the composite scaffolds. The mechanical properties of the composite scaffolds were analyzed by tensile tests for the scaffolds with varying contents of HAp within SF fibers. The mechanical testing showed the peak strengths at the HAp content of 20 wt.%. The increase of HAp content up to 20 wt.% increased the mechanical properties of the composite scaffolds, while further increase above 20 wt.% disrupted the polymer chain networks within SF nanofibers and weakened the mechanical strengths. - Highlights: • Electrospun composite silk fibroin scaffolds were mechanically-reinforced. • GPTMS enhanced hydroxyapatite distribution in silk fibroin nanofibers. • Mechanical property of composite scaffolds increased up to 20% of hydroxyapatite. • Composite

  14. Electrospun tilapia collagen nanofibers accelerating wound healing via inducing keratinocytes proliferation and differentiation.

    Science.gov (United States)

    Zhou, Tian; Wang, Nanping; Xue, Yang; Ding, Tingting; Liu, Xin; Mo, Xiumei; Sun, Jiao

    2016-07-01

    The development of biomaterials with the ability to induce skin wound healing is a great challenge in biomedicine. In this study, tilapia skin collagen sponge and electrospun nanofibers were developed for wound dressing. The collagen sponge was composed of at least two α-peptides. It did not change the number of spleen-derived lymphocytes in BALB/c mice, the ratio of CD4(+)/CD8(+) lymphocytes, and the level of IgG or IgM in Sprague-Dawley rats. The tensile strength and contact angle of collagen nanofibers were 6.72±0.44MPa and 26.71±4.88°, respectively. They also had good thermal stability and swelling property. Furthermore, the nanofibers could significantly promote the proliferation of human keratinocytes (HaCaTs) and stimulate epidermal differentiation through the up-regulated gene expression of involucrin, filaggrin, and type I transglutaminase in HaCaTs. The collagen nanofibers could also facilitate rat skin regeneration. In the present study, electrospun biomimetic tilapia skin collagen nanofibers were succesfully prepared, were proved to have good bioactivity and could accelerate rat wound healing rapidly and effectively. These biological effects might be attributed to the biomimic extracellular matrix structure and the multiple amino acids of the collagen nanofibers. Therefore, the cost-efficient tilapia collagen nanofibers could be used as novel wound dressing, meanwhile effectively avoiding the risk of transmitting animal disease in the future clinical apllication. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Thermal, Electrical and Surface Hydrophobic Properties of Electrospun Polyacrylonitrile Nanofibers for Structural Health Monitoring.

    Science.gov (United States)

    Alarifi, Ibrahim M; Alharbi, Abdulaziz; Khan, Waseem S; Swindle, Andrew; Asmatulu, Ramazan

    2015-10-14

    This paper presents an idea of using carbonized electrospun Polyacrylonitrile (PAN) fibers as a sensor material in a structural health monitoring (SHM) system. The electrospun PAN fibers are lightweight, less costly and do not interfere with the functioning of infrastructure. This study deals with the fabrication of PAN-based nanofibers via electrospinning followed by stabilization and carbonization in order to remove all non-carbonaceous material and ensure pure carbon fibers as the resulting material. Electrochemical impedance spectroscopy was used to determine the ionic conductivity of PAN fibers. The X-ray diffraction study showed that the repeated peaks near 42° on the activated nanofiber film were α and β phases, respectively, with crystalline forms. Contact angle, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) were also employed to examine the surface, thermal and chemical properties of the carbonized electrospun PAN fibers. The test results indicated that the carbonized PAN nanofibers have superior physical properties, which may be useful for structural health monitoring (SHM) applications in different industries.

  16. Electrospun conducting polymer nanofibers and electrical stimulation of nerve stem cells.

    Science.gov (United States)

    Prabhakaran, Molamma P; Ghasemi-Mobarakeh, Laleh; Jin, Guorui; Ramakrishna, Seeram

    2011-11-01

    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 × 10⁻⁹ 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. Copyright © 2011 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  17. Constructing 2D layered MoS2 nanosheets-modified Z-scheme TiO2/WO3 nanofibers ternary nanojunction with enhanced photocatalytic activity

    Science.gov (United States)

    Zhao, Jiangtao; Zhang, Peng; Fan, Jiajie; Hu, Junhua; Shao, Guosheng

    2018-02-01

    Advanced materials for photoelectrochemical H2 production are important to the field of renewable energy. Despite great efforts have been made, the present challenge in materials science is to explore highly active photocatalysts for splitting of water at low cost. In this work, we report a new composite material consisting of 2D layered MoS2 nanosheets grown on the presence of TiO2/WO3 nanofibers (TW) as a high-performance photocatalyst for H2 evolution. This composite material was prepared by a two-step simple process of electrospinning and hydrothermal. We found that the as-prepared TiO2/WO3@MoS2 (TWM) hybrid exhibited superior photocatalytic activity in the hydrogen evolution reaction (HER) even without the noble metal-cocatalyst. Importantly, the TiO2/WO3@MoS2 heterostructure with 60 wt% of MoS2 exhibits the highest hydrogen production rate. This great improvement is attributed to the positive synergetic effect between the WO3 and MoS2 components in this hybrid cocatalyst, which serve as hole collector and electron collector, respectively. Moreover, the effective charge separation was directly proved by ultraviolet photoelectron spectroscopy, electrochemical impedance spectroscopy, and photocurrent analysis.

  18. Electrospun Nanofiber Coating of Fiber Materials: A Composite Toughening Approach

    Science.gov (United States)

    Kohlman, Lee W.; Roberts, Gary D.

    2012-01-01

    Textile-based composites could significantly benefit from local toughening using nanofiber coatings. Nanofibers, thermoplastic or otherwise, can be applied to the surface of the fiber tow bundle, achieving toughening of the fiber tow contact surfaces, resulting in tougher and more damage-resistant/tolerant composite structures. The same technique could also be applied to other technologies such as tape laying, fiber placement, or filament winding operations. Other modifications to the composite properties such as thermal and electrical conductivity could be made through selection of appropriate nanofiber material. Control of the needle electric potential, precursor solution, ambient temperature, ambient humidity, airflow, etc., are used to vary the diameter and nanofiber coating morphology as needed. This method produces a product with a toughening agent applied to the fiber tow or other continuous composite precursor material where it is needed (at interfaces and boundaries) without interfering with other composite processing characteristics.

  19. An electrochemical impedimetric sensor based on biomimetic electrospun nanofibers for formaldehyde.

    Science.gov (United States)

    Dai, Hong; Gong, Lingshan; Xu, Guifang; Li, Xiuhua; Zhang, Shupei; Lin, Yanyu; Zeng, Baoshan; Yang, Caiping; Chen, Guonan

    2015-01-21

    Herein, simple molecular recognition sites for formaldehyde were designed on electrospun polymer nanofibers. In order to improve the conductivity of the electrospun polymer nanofibers, carbon nanotubes were introduced into the resulting nanofibers. By employing these functionalized nanocomposite fibers to fabricate a biomimetic sensor platform, an obvious change caused by recognition between recognition sites and formaldehyde molecules was monitored through electrochemical impedance spectroscopy (EIS). The experimental conditions were optimized and then a quantitative method for formaldehyde sensing in low concentration was established. The relative results demonstrated that the sensor based on biomimetic recognition nanofibers displays an excellent recognition capacity toward formaldehyde. The linear response range of the sensor was between 1 × 10(-6) mol L(-1) and 1 × 10(-2) mol L(-1), with the detection limit of 8 × 10(-7) mol L(-1). The presented research provided a fast, feasible and sensitive method for formaldehyde with good anti-interference capabilities and good stability, which could meet the practical requirement for formaldehyde assay.

  20. Polymorphism in electrospun poly(vinylidene fluoride)/nanoclay composite nanofibers

    Science.gov (United States)

    Yu, Lei; Cebe, Peggy

    2009-03-01

    We investigated the morphology and polymorphism behavior of electrospun (ES) composite nanofibers of poly(vinylidene fluoride) (PVDF) with two nanoclays: Lucentite^TM STN and SWN. Lucentite^TM STN and SWN synthetic nanoclays are based on hectrite structure, but only STN contains an organic modifier between the hectrite layers. The PVDF was dissolved, and nanoclay was dispersed, in N,N-dimethylformamide/acetone and then electrospun into nanofibers with diameters ranging from 100˜1000 nm. The nanoclay content ranged from 0.2% to 10%. The addition of STN can greatly decrease the number of beads and makes the diameter of the ES nanofibers more uniform due to an increase of solution conductivity. From wide angle X-ray scattering and Fourier transform infrared spectroscopy, we found both STN and SWN can induce more beta phase PVDF crystals and TTT conformers, while reducing the alpha phase crystal content in ES PVDF/nanoclay composite nanofibers. STN can completely eliminate the alpha phase crystals, even at low STN content. The ionic organic modifier makes STN much more effective than SWN in promoting beta phase PVDF crystals.

  1. Polylactic acid (PLA)/Silver-NP/VitaminE bionanocomposite electrospun nanofibers with antibacterial and antioxidant activity

    Science.gov (United States)

    Munteanu, Bogdanel Silvestru; Aytac, Zeynep; Pricope, Gina M.; Uyar, Tamer; Vasile, Cornelia

    2014-10-01

    The antibacterial property of silver nanoparticles (Ag-NPs) and the antioxidant activity of Vitamin E have been combined by incorporation of these two active components within polylactic acid (PLA) nanofibers via electrospinning (PLA/Ag-NP/VitaminE nanofibers). The morphological and structural characterizations of PLA/Ag-NP/VitaminE nanofibers were performed by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy and X-ray diffraction. The average fiber diameter was 140 ± 60 nm, and the size of the Ag-NP was 2.7 ± 1.5 nm. PLA/Ag-NP/VitaminE nanofibers inhibited growth of Escherichia coli, Listeria monocytogenes and Salmonella typhymurium up to 100 %. The amount of released Ag ions from the nanofibers immersed in aqueous solution was determined by Inductively Coupled Plasma Mass Spectrometry, and it has been observed that the release of Ag ions was kept approximately constant after 10 days of immersion. The antioxidant activity of PLA/Ag-NP/VitaminE nanofibers was evaluated according to DPPH (2,2-diphenyl-1-picrylhydrazyl) method and determined as 94 %. The results of the tests on fresh apple and apple juice indicated that the PLA/Ag/VitaminE nanofiber membrane actively reduced the polyphenol oxidase activity. The multifunctional electrospun PLA nanofibers incorporating Ag-NP and Vitamin E may be quite applicable in food packaging due to the extremely large surface area of nanofibers along with antibacterial and antioxidant activities. These materials could find application in food industry as a potential preservative packaging for fruits and juices.

  2. Cell behaviors on magnetic electrospun poly-D, L-lactide nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Long; Yang, Guang [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Li, Jinrong; Ding, Shan [School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); Zhou, Shaobing, E-mail: shaobingzhou@swjtu.edu.cn [Key Laboratory of Advanced Technologies of Materials, Ministry of Education, School of Materials Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China); School of Life Science and Engineering, Southwest Jiaotong University, Chengdu 610031 (China)

    2014-01-01

    It is widely accepted that magnetic fields have an influence on cell behaviors, but the effects are still not very clear since the magnetic field's type, intensity and exposure time are different. In this study, a static magnetic field (SMF) in moderate intensity (10 mT) was employed to investigate its effect on osteoblast and 3T3 fibroblast cell behaviors cultured respectively with magnetic polymer nanofiber mats. The magnetic mats composed of random oriented or aligned polymer nanofibers were fabricated by electrospinning the mixed solution of poly-D, L-lactide (PLA) and iron oxide nanoparticles. The fiber morphology was characterized by scanning electron microscopy (SEM), the nanoparticle distribution in fiber matrix was measured with transmission electron microscope (TEM). Mechanical properties of nanofiber mats are studied by uniaxial tensile test. The results showed the nanofibers loaded with magnetic nanoparticles displayed excellent magnetic responsibility and biodegradability. In vitro cytotoxicity analysis demonstrated that the osteoblast proliferation of all fiber mats stimulated with or without SMF was increased with the increase of the culturing days. Furthermore, in the horizontal SMFs, cell orientation tended to deviate from nanofiber orientation to field direction while the nanofiber orientation is perpendicular to the field direction, while the horizonal direction of SMFs could also direct the cell growth orientation. The magnetic nanofiber mats provide a potential platform to explore the cell behaviors under the stimulation of external magnetic field. - Highlights: • The random oriented and aligned magnetic electrospun nanofibers were prepared. • The nanofibers displayed excellent magnetic responsibility and biodegradability. • The horizonal direction of SMFs could also direct the cell growth orientation.

  3. A review on electrospun nanofibers for oral drug delivery

    OpenAIRE

    Abbas Akhgari; Zahra Shakib; Setareh Sanati

    2017-01-01

    Nowadays, polymer nanofibers have gained attention due to remarkable characteristics such as high porosity and large surface area to volume ratio. Among their fabrication methods, electrospinning technique has been attracted as a simple and reproducible approach. It is a versatile, simple and cost-effective technique for the production of continuous nanofibers with acceptable characteristics such as high porosity, high surface area to volume ratio, high loading capacity and encapsulation effi...

  4. Damage-Resistant Composites Using Electrospun Nanofibers: A Multiscale Analysis of the Toughening Mechanisms.

    Science.gov (United States)

    Daelemans, Lode; van der Heijden, Sam; De Baere, Ives; Rahier, Hubert; Van Paepegem, Wim; De Clerck, Karen

    2016-05-11

    Today, fiber-reinforced polymer composites are a standard material in applications where a high stiffness and strength are required at minimal weight, such as aerospace structures, ultralight vehicles, or even flywheels for highly efficient power storage systems. Although fiber-reinforced polymer composites show many advantages compared to other materials, delamination between reinforcing plies remains a major problem limiting further breakthrough. Traditional solutions that have been proposed to toughen the interlaminar region between reinforcing plies have already reached their limit or have important disadvantages such as a high cost or the need for adapted production processes. Recently, electrospun nanofibers have been suggested as a more viable interlaminar toughening method. Although the expected benefits are numerous, the research on composite laminates enhanced with electrospun nanofibrous veils is still very limited. The work that has been done so far is almost exclusively focused on interlaminar fracture toughness tests with different kinds of nanofibers, where typically a trial and error approach has been used. A thorough understanding of the micromechanical fracture mechanisms and the parameters to obtain toughened composites has not been reported as of yet, but it is crucial to advance the research and design highly damage-resistant composites. This article provides such insight by analyzing the nanofiber toughening effect on three different levels for several nanofiber types. Only by combining the results from different levels, a thorough understanding can be obtained. These levels correspond to the hierarchical nature of a composite: the laminate, the interlaminar region, and the matrix resin. It is found that each level corresponds to certain mechanisms that result in a toughening effect. The bridging of microcracks by electrospun nanofibers is the main toughening mechanism resulting in damage resistance. Nevertheless, the way in which the

  5. Gold nanoparticle decorated electrospun nanofibers: A 3D reproducible and sensitive SERS substrate

    Science.gov (United States)

    Liu, Zhicheng; Yan, Zhaodong; Jia, Lu; Song, Ping; Mei, Linyu; Bai, Lu; Liu, Yaqing

    2017-05-01

    The design and fabrication of three-dimensional (3D) nanostructures with fascinating SERS performance have drawn much attention in the field of materials science and nanotechnology. In this work, 3D poly (acrylic acid) (PAA)/poly (vinyl alcohol) (PVA) nanofibrous membrane was used as templates for the electrostatic assembly of gold nanoparticles. The PAA/PVA electrospun nanofibers were crosslinked using a simple thermal treatment, which would prevent the nanofibers from dissolution in the nanoparticle solution. It was found that the gold nanoparticles were uniformly immobilized on the nanofibers, causing high reproducibility of this SERS substrate. The nanocomposite membrane also showed high sensibility for the detection of trace amount of analytes such as 4-aminothiophenol and Rhodamine 6G.

  6. Electrospun PCL/gelatin composite nanofiber structures for effective guided bone regeneration membranes.

    Science.gov (United States)

    Ren, Ke; Wang, Yi; Sun, Tao; Yue, Wen; Zhang, Hongyu

    2017-09-01

    Guided bone regeneration (GBR) membranes have been proved of great benefit for bone tissue engineering due to the improvement of cell attachment and proliferation. To develop GBR membranes with better biocompatibility and more proper degradation ability, here we fabricated polycaprolactone (PCL, polymer)/gelatin (protein) hybrid nanofibrous GBR membranes via electrospinning, followed by crosslinking with genipin. Acetic acid (HAc) was utilized to resolve the phase separation of PCL and gelatin, therefore homogeneous PCL/gelatin hybrid nanofibers with different ratios were successfully prepared. FTIR, XPS, TGA, DSC results proved that the proportion of PCL and gelatin in the as-spun nanofiber membranes could be simply adjusted by changing the weight ratio of PCL and gelatin in the spinning solution. SEM and AFM images demonstrated that all the nanofibers possessed uniform and smooth structures both in two dimension (2D) and three dimension (3D). The mechanical tests showed that these nanofibers exhibited appropriate tensile and strength properties, which were suitable for bone tissue engineering. CCK-8 and SEM images revealed that all the membranes were biocompatible to MC3T3-e1 cells. In addition, the in vitro osteogenesis characterizations, alizarin red in normal medium and osteogenesis medium, indicated that the nanofibers could promote bone formation. Therefore, all these results could suggest that our design of electrospun polymer/protein nanofiber membranes was effective for guided bone regeneration. Copyright © 2017. Published by Elsevier B.V.

  7. Fabrication and Characterization of Electrospun PCL-MgO-Keratin-Based Composite Nanofibers for Biomedical Applications

    Science.gov (United States)

    Boakye, Maame A. D.; Rijal, Nava P.; Adhikari, Udhab; Bhattarai, Narayan

    2015-01-01

    Polymeric nanofibers are of great interest in biomedical applications, such as tissue engineering, drug delivery and wound healing, due to their ability to mimic and restore the function of natural extracellular matrix (ECM) found in tissues. Electrospinning has been heavily used to fabricate nanofibers because of its reliability and effectiveness. In our research, we fabricated poly(ε-caprolactone)-(PCL), magnesium oxide-(MgO) and keratin (K)-based composite nanofibers by electrospinning a blend solution of PCL, MgO and/or K. The electrospun nanofibers were analyzed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), mechanical tensile testing and inductively-coupled plasma optical emission spectroscopy (ICP-OES). Nanofibers with diameters in the range of 0.2–2.2 µm were produced by using different ratios of PCL/MgO and PCL-K/MgO. These fibers showed a uniform morphology with suitable mechanical properties; ultimate tensile strength up to 3 MPa and Young’s modulus 10 MPa. The structural integrity of nanofiber mats was retained in aqueous and phosphate buffer saline (PBS) medium. This study provides a new composite material with structural and material properties suitable for potential application in tissue engineering. PMID:28793426

  8. Fabrication and Characterization of Electrospun PCL-MgO-Keratin-Based Composite Nanofibers for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Maame A. D. Boakye

    2015-07-01

    Full Text Available Polymeric nanofibers are of great interest in biomedical applications, such as tissue engineering, drug delivery and wound healing, due to their ability to mimic and restore the function of natural extracellular matrix (ECM found in tissues. Electrospinning has been heavily used to fabricate nanofibers because of its reliability and effectiveness. In our research, we fabricated poly(ε-caprolactone-(PCL, magnesium oxide-(MgO and keratin (K-based composite nanofibers by electrospinning a blend solution of PCL, MgO and/or K. The electrospun nanofibers were analyzed by scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR, mechanical tensile testing and inductively-coupled plasma optical emission spectroscopy (ICP-OES. Nanofibers with diameters in the range of 0.2–2.2 µm were produced by using different ratios of PCL/MgO and PCL-K/MgO. These fibers showed a uniform morphology with suitable mechanical properties; ultimate tensile strength up to 3 MPa and Young’s modulus 10 MPa. The structural integrity of nanofiber mats was retained in aqueous and phosphate buffer saline (PBS medium. This study provides a new composite material with structural and material properties suitable for potential application in tissue engineering.

  9. Preparation and characterization of electrospun in-situ cross-linked gelatin-graphite oxide nanofibers.

    Science.gov (United States)

    Zhan, Jianchao; Morsi, Yosry; Ei-Hamshary, Hany; Al-Deyab, Salem S; Mo, Xiumei

    2016-01-01

    Electrospun gelatin(Gel) nanofibers scaffold has such defects as poor mechanical property and quick degradation due to high solubility. In this study, the in situ cross-linked electrospinning technique was used for the production of gelatin nanofibers. Deionized water was chosen as the spinning solvent and graphite oxide (GO) was chosen as the enhancer. The morphological structure, porosity, thermal property, moisture absorption, and moisture retention performance, hydrolysis resistance, mechanical property, and biocompatibility of the produced nanofibers were investigated. Compared with in situ cross-linked gelatin nanofibers scaffold, in situ cross-linked Gel-GO nanofibers scaffold has the following features: (1) the hydrophilicity, moisture absorption, and moisture retention performance slightly reduce, while the hydrolysis resistance is improved; (2) the breaking strength, breaking elongation, and Young's modulus are significantly improved; (3) the porosity slightly reduces while the biocompatibility considerably increases. The in situ cross-linked Gel-GO nanofibers scaffold is likely to be applied in such fields as drug delivery and scaffold for skin tissue engineering.

  10. Electrospun poly(l-lactide)/zein nanofiber mats loaded with Rana chensinensis skin peptides for wound dressing.

    Science.gov (United States)

    Zhang, Mei; Li, Xueqi; Li, Siming; Liu, Yongjia; Hao, Linlin

    2016-09-01

    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.

  11. Effects of quaternization on the morphological stability and antibacterial activity of electrospun poly(DMAEMA-co-AMA) nanofibers.

    Science.gov (United States)

    Xu, Jing-Wei; Wang, Yao; Yang, Yun-Feng; Ye, Xiang-Yu; Yao, Ke; Ji, Jian; Xu, Zhi-Kang

    2015-09-01

    Electrospun nanofibers with antibacterial activity are greatly promising for medical treatment and water purification. Herein we report antibacterial nanofibers electrospun from a series of poly(dimethylamino ethyl methacrylate-co-alkyl methacrylates) (poly(DMAEMA-co-AMA)) and to distinguish the effects of free and cross-linked cations derived from quanternization on the antibacterial activity. Poly(DMAEMA-co-AMA)s are simply synthesized by free radical polymerization from commercial monomers. DSC analysis indicates that they have Tg lower than room temperature and thus the electrospun nanofibers adhere to each other and evenly tend to form films, instead of keeping cylinderic shape. Benzyl chloride (BC) and p-xylylene dichloride (XDC) can quaternize DMAEMA units and to generate cations on the nanofiber surface. XPS analysis and colorimetric assay determine the quaternization degree and the surface accessible quaternary amines (N(+)), respectively. It is very promising that this quaternization endows the electrospun nanofibers with both stable morphology and antibacterial activity. The BC-quaternized fibers show better antibacterial behavior against Escherichia coli and Staphylococcus aureus than those of the XDC-quaternized/cross-linked ones, because cross-linking suppresses the chain mobility of cations. Our results confirm that antibacterial nanofibers can be facilely prepared and chain mobility of the formed cations is the necessary prerequisite for their antibacterial activity. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Encapsulation of plai oil/2-hydroxypropyl-β-cyclodextrin inclusion complexes in polyvinylpyrrolidone (PVP) electrospun nanofibers for topical application.

    Science.gov (United States)

    Tonglairoum, Prasopchai; Chuchote, Tudduo; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Opanasopit, Praneet

    2014-06-01

    The aim of this study was to prepare electrospun polyvinylpyrrolidone (PVP)/2-hydroxypropyl-β-cyclodextrin (HPβCD) nanofiber mats and to incorporate plai oil (Zingiber Cassumunar Roxb.). The plai oil with 10, 20 and 30% wt to polymer were incorporated in the PVP/HPβCD solution and electrospun to obtain nanofibers. The morphology and structure of the PVP and PVP/HPβCD nanofiber mats with and without the plai oil were analyzed using scanning electron microscopy (SEM). The thermal behaviors of the nanofiber mats were characterized using differential scanning calorimeter (DSC). Terpinen-4-ol was used as a marker of the plai oil. The amount of plai oil remaining in the PVP/HPβCD nanofiber mats was determined using gas chromatography-mass spectoscopy (GC-MS). The SEM images revealed that all of the fibers were smooth. The average diameter of fibers was 212-450 nm, and decreased with the increasing of plai oil content. The release characteristics of plai oil from the fiber showed the fast release followed by a sustained release over the experimental time of 24 h. The release rate ranged was in the order of 10% > 20% ∼ 30% plai oil within 24 h. Electrospun fibers with 20% plai oil loading provided the controlled release and also showed the highest plai oil content. Hence, this electrospun nanofiber has a potential for use as an alternative topical application.

  13. Osteoblast function on electrically conductive electrospun PLA/MWCNTs nanofibers.

    Science.gov (United States)

    Shao, Shijun; Zhou, Shaobing; Li, Long; Li, Jinrong; Luo, Chao; Wang, Jianxin; Li, Xiaohong; Weng, Jie

    2011-04-01

    The electrospinning process was utilized successfully to fabricate the random oriented and aligned electrically conductive nanofibers of biodegradable poly-DL-lactide (PLA) in which multiwalled carbon nanotubes (MWCNTs) were embedded. The topographical features of the composite nanofibers were characterized by SEM. The dispersion and alignment of MWCNTs in nanofiber matrix were observed by TEM. The in vitro degradation was characterized in terms of the morphological change, the mass loss and the reduction of polymer molecular weight as well as the decrease of pH value of degradation media. In particular, these conductive nanofiber meshes offered a unique system to study the synergistic effect of topographic cues and electrical stimulation on osteoblasts outgrowth as a way of exploring their potential application in bone tissue engineering. The results of obsteoblasts assay unstimulated showed that the aligned nanofibers as topographic cues could enhance the extension and direct the outgrowth of obsteoblasts better than random fibers. In the presence of direct current (DC) of 100 μA, the obsteoblasts on all samples grew along the electrical current direction. The cellular elongation and proliferation were mainly dependent on the electrical stimulation whereas the topographical features played a minor role in them. Therefore, electrical stimulation with an appropriate DC value imparted on conductive substrate had great potential in application of bone tissue engineering. Copyright © 2011 Elsevier Ltd. All rights reserved.

  14. Tolnaftate-Loaded PolyacrylateElectrospun Nanofibers for an Impressive Regimen on Dermatophytosis

    Directory of Open Access Journals (Sweden)

    Shashi Kiran Misra

    2017-11-01

    Full Text Available Dermatophytosis, topical fungal infection is the most common cause of skin bug in the world, generally underestimated and ignored. It is commonly caused by immensely mortifying and keratinophilic fungal eukaryotes which invade keratinized tissues and generate different tinea diseases in Mediterranean countries. We herein fabricated nanofibers/scaffolds embedded with thiocarbamate derivative topical antifungal tolnaftatefor the first time to target the complete elimination of dermatophyte at the site of infection. In this regard, variable combinations of biocompatible Eudragit grades (ERL100 and ERS100 were selected to provide better adhesion on the site of dermatophytosis, ample absorption of exudates during treatment, and customized controlled drug release. Surface topography analysis indicated that the fabricated nanofibers were regular and defect-free, comprising distinct pockets with nanoscaled diameters. Characterization and compatibility studies of tolnaftate, polymers, and their nanofibers were performed through ATR-FTIR, TGA, and PXRD. Remarkable hydrophilicity and an excellent swelling index were obtained from a 3:1 ratio of ERL100/ERS100 electrospun D3 nanofibers, which is an essential benchmark for the fabrication of nanofibrous scaffolds for alleviating dermatophytosis. In vitro drug release investigation revealed that a nonwoven nanomesh of nanofibers could control the rate of drug release for 8 h. A microdilution assay exhibited inhibition of more than 95% viable cells of Trichophyton rubrum for 96 h. However, Microsporum species rigidly restricted the effect of bioactive antifungal nanofibers and hence showed resistance. In vivo activity on Trichophyton rubrum infected Swiss albino mice revealed complete inhibition of fungal pathogens on successive applications of D3 nanofibers for 7 days. This investigation suggests potential uses of tolnaftate loaded polyacrylate nanofibers as dressing materials/scaffolds for effective

  15. Fabrication and Characterization of New Composite Tio2 Carbon Nanofiber Anodic Catalyst Support for Direct Methanol Fuel Cell via Electrospinning Method

    Science.gov (United States)

    Abdullah, N.; Kamarudin, S. K.; Shyuan, L. K.; Karim, N. A.

    2017-12-01

    Platinum (Pt) is the common catalyst used in a direct methanol fuel cell (DMFC). However, Pt can lead towards catalyst poisoning by carbonaceous species, thus reduces the performance of DMFC. Thus, this study focuses on the fabrication of a new composite TiO2 carbon nanofiber anodic catalyst support for direct methanol fuel cells (DMFCs) via electrospinning technique. The distance between the tip and the collector (DTC) and the flow rate were examined as influencing parameters in the electrospinning technique. To ensure that the best catalytic material is fabricated, the nanofiber underwent several characterizations and electrochemical tests, including FTIR, XRD, FESEM, TEM, and cyclic voltammetry. The results show that D18, fabricated with a flow rate of 0.1 mLhr-1 and DTC of 18 cm, is an ultrafine nanofiber with the smallest average diameter, 136.73 ± 39.56 nm. It presented the highest catalyst activity and electrochemical active surface area value as 274.72 mAmg-1 and 226.75m2 g-1 PtRu, respectively, compared with the other samples.

  16. Fabrication and Characterization of New Composite Tio2Carbon Nanofiber Anodic Catalyst Support for Direct Methanol Fuel Cell via Electrospinning Method.

    Science.gov (United States)

    Abdullah, N; Kamarudin, S K; Shyuan, L K; Karim, N A

    2017-12-06

    Platinum (Pt) is the common catalyst used in a direct methanol fuel cell (DMFC). However, Pt can lead towards catalyst poisoning by carbonaceous species, thus reduces the performance of DMFC. Thus, this study focuses on the fabrication of a new composite TiO 2 carbon nanofiber anodic catalyst support for direct methanol fuel cells (DMFCs) via electrospinning technique. The distance between the tip and the collector (DTC) and the flow rate were examined as influencing parameters in the electrospinning technique. To ensure that the best catalytic material is fabricated, the nanofiber underwent several characterizations and electrochemical tests, including FTIR, XRD, FESEM, TEM, and cyclic voltammetry. The results show that D18, fabricated with a flow rate of 0.1 mLhr -1 and DTC of 18 cm, is an ultrafine nanofiber with the smallest average diameter, 136.73 ± 39.56 nm. It presented the highest catalyst activity and electrochemical active surface area value as 274.72 mAmg -1 and 226.75m 2  g -1 PtRu , respectively, compared with the other samples.

  17. Effect of micropatterning induced surface hydrophobicity on drug release from electrospun cellulose acetate nanofibers

    Science.gov (United States)

    Adepu, Shivakalyani; Gaydhane, Mrunalini K.; Kakunuri, Manohar; Sharma, Chandra S.; Khandelwal, Mudrika; Eichhorn, Stephen J.

    2017-12-01

    Sustained release and prevention of burst release for low half-life drugs like Diclofenac sodium is crucial to prevent drug related toxicity. Electrospun nanofibers have emerged recently as potential carrier materials for controlled and sustained drug release. Here, we present a facile method to prevent burst release by tuning the surface wettability through template assisted micropatterning of drug loaded electrospun cellulose acetate (CA) nanofibers. A known amount of drug (Diclofenac sodium) was first mixed with CA and then electrospun in the form of a nanofabric. This as-spun network was hydrophilic in nature. However, when electrospinning was carried out through non-conducting templates, viz nylon meshes with 50 and 100 μm size openings, two kinds of hydrophobic micro-patterned CA nanofabrics were produced. In vitro transdermal testing of our nanofibrous mats was carried out; these tests were able to show that it would be possible to create a patch for transdermal drug release. Further, our results show that with optimized micro-patterned dimensions, a zero order sustained drug release of up to 12 h may be achieved for the transdermal system when compared to non-patterned samples. This patterning caused a change in the surface wettability, to a hydrophobic surface, resulting in a controlled diffusion of the hydrophilic drug. Patterning assisted in controlling the initial burst release, which is a significant finding especially for low half-life drugs.

  18. Method for Coating a Tow with an Electrospun Nanofiber

    Science.gov (United States)

    Kohlman, Lee W. (Inventor); Roberts, Gary D. (Inventor)

    2015-01-01

    Method and apparatus for enhancing the durability as well as the strength and stiffness of prepreg fiber tows of the sort used in composite materials are disclosed. The method involves adhering electrospun fibers onto the surface of such composite materials as filament-wound composite objects and the surface of prepreg fiber tows of the sort that are subsequently used in the production of composite materials of the filament-wound, woven, and braided sorts. The apparatus performs the methods described herein.

  19. Porous Carbon Nanofibers from Electrospun Biomass Tar/Polyacrylonitrile/Silver Hybrids as Antimicrobial Materials.

    Science.gov (United States)

    Song, Kunlin; Wu, Qinglin; Zhang, Zhen; Ren, Suxia; Lei, Tingzhou; Negulescu, Ioan I; Zhang, Quanguo

    2015-07-15

    A novel route to fabricate low-cost porous carbon nanofibers (CNFs) using biomass tar, polyacrylonitrile (PAN), and silver nanoparticles has been demonstrated through electrospinning and subsequent stabilization and carbonization processes. The continuous electrospun nanofibers had average diameters ranging from 392 to 903 nm. The addition of biomass tar resulted in increased fiber diameters, reduced thermal stabilities, and slowed cyclization reactions of PAN in the as-spun nanofibers. After stabilization and carbonization, the resultant CNFs showed more uniformly sized and reduced average diameters (226-507 nm) compared to as-spun nanofibers. The CNFs exhibited high specific surface area (>400 m(2)/g) and microporosity, attributed to the combined effects of phase separations of the tar and PAN and thermal decompositions of tar components. These pore characteristics increased the exposures and contacts of silver nanoparticles to the bacteria including Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli, leading to excellent antimicrobial performances of as-spun nanofibers and CNFs. A new strategy is thus provided for utilizing biomass tar as a low-cost precursor to prepare functional CNFs and reduce environmental pollutions associated with direct disposal of tar as an industrial waste.

  20. Lignin-Based Electrospun Nanofibers Reinforced with Cellulose Nanocrystals

    Science.gov (United States)

    Mariko Ago; Kunihiko Okajima; Joseph E. Jakes; Park Sunkyu; Orlando J. Rojas

    2012-01-01

    Lignin-based fibers were produced by electrospinning aqueous dispersions of lignin, poly(vinyl alcohol) (PVA), and cellulose nanocrystals (CNCs). Defect-free nanofibers with up to 90 wt % lignin and 15% CNCs were achieved. The properties of the aqueous dispersions, including viscosity, electrical conductivity, and surface tension, were examined and correlated to the...

  1. Electrospun propolis/polyurethane composite nanofibers for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeong In [Department of Bio-nano System Engineering, Chonbuk National University, Jeonju 561–756 (Korea, Republic of); Pant, Hem Raj, E-mail: hempant@jbnu.ac.kr [Department of Bio-nano System Engineering, Chonbuk National University, Jeonju 561–756 (Korea, Republic of); Department of Engineering Science and Humanities, Pulchowk Campus, Tribhuvan University, Kathmandu (Nepal); Research Institute for Next Generation, Kalanki, Kathmandu (Nepal); Sim, Hyun-Jaung [Department of Bioactive Material Science, Research Center of Bioactive Material, Chonbuk National University, Jeonju, Chonbuk (Korea, Republic of); Lee, Kang Min [Department of Molecular Biology, College of Natural Science, Chonbuk National University, Jeonju, 561–756 (Korea, Republic of); Kim, Cheol Sang, E-mail: chskim@jbnu.ac.kr [Department of Bio-nano System Engineering, Chonbuk National University, Jeonju 561–756 (Korea, Republic of)

    2014-11-01

    Tissue engineering requires functional polymeric membrane for adequate space for cell migration and attachment within the nanostructure. Therefore, biocompatible propolis loaded polyurethane (propolis/PU) nanofibers were successfully prepared using electrospinning of propolis/PU blend solution. Here, composite nanofibers were subjected to detailed analysis using electron microscopy, FT-IR spectroscopy, thermal gravimetric analysis (TGA), and mechanical properties and water contact angle measurement. FE-SEM images revealed that the composite nanofibers became point-bonded with increasing amounts of propolis in the blend due to its adhesive properties. Incorporation of small amount of propolis through PU matrix could improve the hydrophilicity and mechanical strength of the fibrous membrane. In order to assay the cytocompatibility and cell behavior on the composite scaffolds, fibroblast cells were seeded on the matrix. Results suggest that the incorporation of propolis into PU fibers could increase its cell compatibility. Moreover, composite nanofibers have effective antibacterial activity. Therefore, as-synthesized nanocomposite fibrous mat has great potentiality in wound dressing and skin tissue engineering. - Highlights: • Sufficient amount of propolis is simply loaded through PU fibers. • Propolis increases the hydrophilicity and mechanical properties of PU fibers. • Composite mat shows excellent antibacterial activity. • Small amount of propolis can enhance the cell compatibility of PU fibers.

  2. Cellulose nanofiber-templated three-dimension TiO 2 hierarchical nanowire network for photoelectrochemical photoanode

    Science.gov (United States)

    Zhaodong Li; Chunhua Yao; Fei Wang; Zhiyong Cai; Xudong Wang

    2014-01-01

    Three dimensional (3D) nanostructures with extremely large porosity possess a great promise for the development of high-performance energy harvesting storage devices. In this paper, we developed a high-density 3D TiO2 fiber-nanorod (NR) heterostructure for photoelectrochemical (PEC) water splitting. The hierarchical structure was synthesized on a...

  3. Effects of substrate on piezoelectricity of electrospun poly(vinylidene fluoride)-nanofiber-based energy generators.

    Science.gov (United States)

    Lee, Byoung-Sun; Park, Boongik; Yang, Ho-Sung; Han, Jin Woo; Choong, Chweelin; Bae, Jihyun; Lee, Kihwan; Yu, Woong-Ryeol; Jeong, Unyong; Chung, U-In; Park, Jong-Jin; Kim, Ohyun

    2014-03-12

    We report the effects of various substrates and substrate thicknesses on electrospun poly(vinylidene fluoride) (PVDF)-nanofiber-based energy harvesters. The electrospun PVDF nanofibers showed an average diameter of 84.6 ± 23.5 nm. A high relative β-phase fraction (85.2%) was achieved by applying high voltage during electrospinning. The prepared PVDF nanofibers thus generated considerable piezoelectric potential in accordance with the sound-driven mechanical vibrations of the substrates. Slide glass, poly(ethylene terephthalate), poly(ethylene naphthalate), and paper substrates were used to investigate the effects of the intrinsic and extrinsic substrate properties on the piezoelectricity of the energy harvesters. The thinnest paper substrate (66 μm) with a moderate Young's modulus showed the highest voltage output (0.4885 V). We used high-performance 76, 66, and 33 μm thick papers to determine the effect of paper thickness on the output voltage. The thinnest paper substrate resulted in the highest voltage output (0.7781 V), and the numerical analyses of the sound-driven mechanical deformation strongly support the hypothesis that substrate thickness has a considerable effect on piezoelectric performance.

  4. Electrospun PLA/MWCNTs composite nanofibers for combined chemo- and photothermal therapy.

    Science.gov (United States)

    Zhang, Z; Liu, S; Xiong, H; Jing, X; Xie, Z; Chen, X; Huang, Y

    2015-10-01

    Carbon nanotubes are effective thermal generators by absorbing near-infrared radiation (NIR). In this study, multiwalled carbon nanotubes (MWCNTs) and doxorubicin (DOX) were successfully electrospun into the poly-l-lactic acid (PLLA) nanofibers. It is confirmed that NIR radiation could not only initiate burst release of DOX from the fibers due to the relatively low glass transition temperature (Tg) of PLLA, but also significantly increase the temperature of fibers-covering tumor site. The multifunctional fibers showed increased cytotoxicity both in vitro and in vivo by the combination of photothermal induced hyperthermia and chemotherapy with DOX. This drug delivery system could be very useful and convenient in future clinical applications for localized cancer therapy. Combination of chemo- and photothermal therapy has been widely researched owing to its enhanced cancer treatment efficacy. In this study, chemotherapy and photothermal therapy were integrated into one single system using electrospun DOX/MWCNTs loaded PLLA nanofiber mats and the anti-cancer efficacy of the fibers was studied in vivo for the first time. The effective NIR irradiation control showed a typical switch on/off effect on the release behavior of drug. As local delivery system, the fibers maximize the drug concentration in tumor and keep the MWCNTs in the surroundings of tumor, thus allowing a repeated localized heating. The high porosity of nanofibers is easy for cell binding, which may present an attractive alternative for local hyperthermia treatment of easily metastasizing tumors. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  5. Preparation and evaluation of electrospun nanofibers containing pectin and time-dependent polymers aimed for colonic drug delivery of celecoxib

    Directory of Open Access Journals (Sweden)

    A. Akhgari

    2016-01-01

    Full Text Available Objective(s:The aim of this study was to prepare electrospun nanofibers of celecoxib using combination of time-dependent polymers with pectin to achieve a colon-specific drug delivery system for celecoxib. Materials and Methods:Formulations were produced based on two multilevel 22 full factorial designs. The independent variables were the ratio of drug:time-dependent polymer (X1 and the amount of pec­tin in formulations (X2. Electrospinning process was used for preparation of nanofibers. The spinning solutions were loaded in 5 mL syringes. The feeding rate was fixed by a syringe pump at 2.0 mL/h and a high voltage supply at range 10-18 kV was applied for electrospinning. Electrospun nanofibers were collected and evaluated by scanning electron microscopy and drug release in the acid and buffer with pH 6.8 with and without pectinase. Results:Electrospun nanofibers of celecoxib with appropriate morphological properties were produced via electrospinning process. Drug release from electrospun nanofibers was very low in the acidic media; while, drug release in the simulated colonic media was the highest from formulations containing pectin. Conclusion: Formulation F2 (containing drug:ERS with the ratio of 1:2 and 10% pectin exhibited acceptable morphological characteristics and protection of drug in the upper GI tract and could be a good candidate as a colonic drug delivery system for celecoxib.

  6. Electrospun carboxyl multi-walled carbon nanotubes grafted polyhydroxybutyrate composite nanofibers membrane scaffolds: Preparation, characterization and cytocompatibility.

    Science.gov (United States)

    Zhijiang, Cai; Cong, Zhu; Jie, Guo; Qing, Zhang; Kongyin, Zhao

    2018-01-01

    Electrospun polyhydroxybutyrate (PHB)/carboxyl multi-walled carbon nanotubes grafted polyhydroxybutyrate (CMWCNT-g-PHB) composite nanofibers scaffolds were fabricated by electrospinning technology. The grafted product CMWCNT-g-PHB was prepared by condensation reactions between the carboxyl groups of CMWCNT and hydroxyl groups of PHB molecules and characterized by FTIR, XRD, XPS, TG and TEM measurements. The surface morphology, hydrophilicity and tensile mechanical properties of the electrospun PHB/CMWCNT-g-PHB composite nanofibers membrane scaffolds were investigated. The values of tensile strength, breaking elongation rate, initial modulus and fracture energy of the composite nanofibers scaffolds can reach to 4.64MPa, 255.59%, 88MPa and 109.73kJ/m2, respectively. The biodegradability and cytocompatibility of the electrospun composite nanofibers scaffolds were preliminarily evaluated. The as-prepared electrospun PHB/CMWCNT-g-PHB composite nanofibers scaffolds with the characteristics of large specific area, high porosity, good biodegradability and cytocompatibility as well as sufficient mechanical properties should be more promising in the field of tissue engineering scaffolds and biological medicine. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. TiO2/ZnO and ZnO/TiO2 core/shell nanofibers prepared by electrospinning and atomic layer deposition for photocatalysis and gas sensing

    Science.gov (United States)

    Boyadjiev, Stefan I.; Kéri, Orsolya; Bárdos, Péter; Firkala, Tamás; Gáber, Fanni; Nagy, Zsombor K.; Baji, Zsófia; Takács, Máté; Szilágyi, Imre M.

    2017-12-01

    In the present work, core TiO2 and ZnO oxide nanofibers were prepared by electrospinning, then shell oxide (ZnO, TiO2) layers were deposited on them by atomic layer deposition (ALD). The aim of preparing ZnO and TiO2 nanofibers, as well as ZnO/TiO2 and TiO2/ZnO nanocomposites is to study the interaction between the oxide materials when a pure oxide fiber is covered with thin film of the other oxide, and explore the influence of exchanging the core and shell materials on their photocatalytic and gas sensing properties. The composition, structure and morphology of the pure and composite nanofibers were studied by SEM-EDX, TEM, XRD, FTIR, UV-vis and Raman. The photocatalytic activity of the as-prepared materials was analyzed by UV-vis spectroscopy through decomposing aqueous methyl orange under UV irradiation. The gas sensing of the nanofibers was investigated by detecting 100 ppm NH3 at 150 and 220 °C using interdigital electrode based sensors.

  8. Supercapacitor Electrodes Based on High-Purity Electrospun Polyaniline and Polyaniline-Carbon Nanotube Nanofibers.

    Science.gov (United States)

    Simotwo, Silas K; DelRe, Christopher; Kalra, Vibha

    2016-08-24

    Freestanding, binder-free supercapacitor electrodes based on high-purity polyaniline (PANI) nanofibers were fabricated via a single step electrospinning process. The successful electrospinning of nanofibers with an unprecedentedly high composition of PANI (93 wt %) was made possible due to blending ultrahigh molecular weight poly(ethylene oxide) (PEO) with PANI in solution to impart adequate chain entanglements, a critical requirement for electrospinning. To further enhance the conductivity and stability of the electrodes, a small concentration of carbon nanotubes (CNTs) was added to the PANI/PEO solution prior to electrospinning to generate PANI/CNT/PEO nanofibers (12 wt % CNTs). Scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) porosimetry were conducted to characterize the external morphology of the nanofibers. The electrospun nanofibers were further probed by transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The electroactivity of the freestanding PANI and PANI/CNT nanofiber electrodes was examined using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy. Competitive specific capacitances of 308 and 385 F g(-1) were achieved for PANI and PANI-CNT based electrodes, respectively, at a current density of 0.5 A g(-1). Moreover, specific capacitance retentions of 70 and 81.4% were observed for PANI and PANI-CNT based electrodes, respectively, after 1000 cycles. The promising electrochemical performance of the fabricated electrodes, we believe, stems from the porous 3-D electrode structure characteristic of the nonwoven interconnected nanostructures. The interconnected nanofiber network facilitates efficient electron conduction while the inter- and intrafiber porosity enable excellent electrolyte penetration within the polymer matrix, allowing fast ion transport to the active sites.

  9. Towards Scalable Binderless Electrodes: Carbon Coated Silicon Nanofiber Paper via Mg Reduction of Electrospun SiO2 Nanofibers

    Science.gov (United States)

    Favors, Zachary; Bay, Hamed Hosseini; Mutlu, Zafer; Ahmed, Kazi; Ionescu, Robert; Ye, Rachel; Ozkan, Mihrimah; Ozkan, Cengiz S.

    2015-02-01

    The need for more energy dense and scalable Li-ion battery electrodes has become increasingly pressing with the ushering in of more powerful portable electronics and electric vehicles (EVs) requiring substantially longer range capabilities. Herein, we report on the first synthesis of nano-silicon paper electrodes synthesized via magnesiothermic reduction of electrospun SiO2 nanofiber paper produced by an in situ acid catalyzed polymerization of tetraethyl orthosilicate (TEOS) in-flight. Free-standing carbon-coated Si nanofiber binderless electrodes produce a capacity of 802 mAh g-1 after 659 cycles with a Coulombic efficiency of 99.9%, which outperforms conventionally used slurry-prepared graphite anodes by over two times on an active material basis. Silicon nanofiber paper anodes offer a completely binder-free and Cu current collector-free approach to electrode fabrication with a silicon weight percent in excess of 80%. The absence of conductive powder additives, metallic current collectors, and polymer binders in addition to the high weight percent silicon all contribute to significantly increasing capacity at the cell level.

  10. Oxygen-rich carbon-nitrogen quantum dots as cocatalysts for enhanced photocatalytic H2 production activity of TiO2 nanofibers

    Directory of Open Access Journals (Sweden)

    Zhiyan Chen

    2017-06-01

    Full Text Available We developed an one-step hydrothermal method to synthesize carbon-nitrogen quantum dots (CNQDs with oxygen-rich functional groups. The sample was characterized by TEM, AFM, FT-IR, XPS, UV–vis absorption and PL spectra. The O/C and N/C atomic ratio of typical CNQDs with diameters of 3–6 nm are ca. 0.4 and 0.2, respectively. Without noble metal cocatalyst, the photocatalytic H2 production rate of CNQDs/TiO2 nanofibers (NFs (112.4 μmol h−1 g−1 is 1.8 times higher than that of TiO2 NFs. The good absorption of light contributes to the enhanced photocatalytic H2 performance. The CNQDs could be promising in biomedical imaging, optical data recording storage and photo/electrocatalysis, etc.

  11. Electrospun Direct-write Multi-functional Nanofibers

    Science.gov (United States)

    Chang, Jiyoung

    Multi-functional fibers by means of direct-write near-field electrospinning process have been developed for versatile applications on a wide variety of substrates, including flexible ones. Several maskless lithography techniques have been established by using the direct-write fibers in dry etching, wet etching and lift-off processes. By selecting the proper functional materials, electrospun direct-write fibers have been demonstrated in prototype working devices, such as large array piezoelectric nanogenerators made of polymeric PVDF (Polyvinylidene fluoride) and direct-write micro heaters made of metallic copper nanoparticles. In the first example, continuous yet uniform PVDF fibers have been electrospun on a flexible substrate. A post, electrical poling process has been introduced on electrodes with PDMS (Polydimethylsiloxane) as the filling media to achieve an electrical potential of 2x107 V/m. In the prototype device, 500 energy harvesting points formed by 50 pairs of fibers and 10 pairs of comb-shape electrodes have generated about 30nA of electrical current on a flexible substrate under an estimated strain of 0.1%. Both FTIR (Fourier Transform Infrared Spectroscopy) and XRD (X-Ray Diffraction) have been utilized to characterize the electrospun fibers and good beta-phase formation, an essential property for piezoelectricity, has been confirmed. For the next example, electrospun direct-write fibers have been employed to show three maskless lithography techniques; lift-off, wet-etching and dry-etching. These include the demonstration of sub-micrometer wide gaps between a thin metallic gold film using the lift-off process; 20microm-wide, 20mm-long lineshape micro heaters made of 30nm-thick copper film by a wet-etching process; and a 2microm-wide, 10microm-long graphene channel FET (Field Effect Transistor) via a dry-etching process. Electrospun PEO (Polyethylene oxide) fibers have been utilized in the aformentioned processes which has shown strong adhesion to the

  12. Investigation of microalgae growth on electrospun nanofiber mats

    Directory of Open Access Journals (Sweden)

    Christina Großerhode

    2017-08-01

    Full Text Available Due to their large inner surface, nanofiber mats are often used in tissue engineering and examined with respect to cell adhesion, e.g., for cultivation of fibroblasts. The combination of different polymers with a large contact area, however, could also be used for growth of different plants including green microalgae. Here, the cultivation of the microalga Chlamydomonas reinhardtii on different polymer substrates was examined. We investigated growth on two nanofiber mats consisting of polyamide (PA6 and polyacrylonitrile (PAN and a polypropylene (PP microfiber mat as substrates, compared with a pure multi-well plate. It was found that the algae were able to grow on all textile mats without change in morphology, indicating that all polymers were non-toxic to the cells. Thus, these nonwovens might be suitable filters for the separation of microalgae in biotechnological processes.

  13. Mixed effect of main electrospinning parameters on the β-phase crystallinity of electrospun PVDF nanofibers

    Science.gov (United States)

    Jiyong, Hu; Yinda, Zhu; Hele, Zhang; Yuanyuan, Gu; Xudong, Yang

    2017-08-01

    Electrospun polyvinylidene fluoride (PVDF) nanofiber has shown its advantages of producing piezoelectric devices. Although the effect of electrospinning parameters on the formation of β crystalline phase has been investigated, their mixed effect has not been fully understood. In this study, two dependent design of experiments were utilized to systematically control the transformation of crystalline phases by three typical electrospinning parameters, i.e. applied voltage, needle tip diameter and feeding flow rate, and the mixed interaction of these parameters in improving the fraction of β crystalline phase was investigated. The structures and the contents of crystalline phases within PVDF nanofibers were analyzed by Fourier transform infrared spectra and x-ray diffraction patterns. The results of single factorial experiments showed that all of three electrospinning parameters have a significant effect on the formation and fraction of β-phase crystallinity of electrospun PVDF nanofibers. Furthermore, both the fraction and the crystallinity of β phase initially increase and then decrease with an increase of applied voltage, and consistently decrease with the needle-tip diameter. However, the β-phase fraction parabolically increases with the increasing feeding flow rates, whereas its crystallinity linearly deceases. The orthogonal experimental results demonstrated that the mixed effect of three electrospinning parameters is different from that of single parameter on the fraction of β-phase crystalline, and that the feeding flow rates among three parameters have the greatest effect. Taken together, these results suggested a new strategy to improve the β-phase fraction of electrospun PVDF fibers via sequence of priority of electrospinning parameters.

  14. A Review of Electrospun Conductive Polyaniline Based Nanofiber Composites and Blends: Processing Features, Applications, and Future Directions

    Directory of Open Access Journals (Sweden)

    Saiful Izwan Abd Razak

    2015-01-01

    Full Text Available Electrospun polymer nanofibers with high surface area to volume ratio and tunable characteristic are formed through the application of strong electrostatic field. Electrospinning has been identified as a straight forward and viable technique to produce nanofibers from polymer solution as their initial precursor. These nanofiber materials have attracted attention of researchers due to their enhanced and exceptional nanostructural characteristics. Electrospun polyaniline (PANI based nanofiber is one of the important new materials for the rapidly growing technology development such as nanofiber based sensor devices, conductive tissue engineering scaffold materials, supercapacitors, and flexible solar cells applications. PANI however is relatively hard to process compared to that of other conventional polymers and plastics. The processing of PANI is daunting, mainly due to its rigid backbone which is related to its high level of conjugation. The challenges faced in the electrospinning processing of neat PANI have alternatively led to the development of the electrospun PANI based composites and blends. A review on the research activities of the electrospinning processing of the PANI based nanofibers, the potential prospect in various fields, and their future direction are presented.

  15. Electrospun Metal Nanofiber Webs as High-Performance Transparent Electrode

    KAUST Repository

    Wu, Hui

    2010-10-13

    Transparent electrodes, indespensible in displays and solar cells, are currently dominated by indium tin oxide (ITO) films although the high price of indium, brittleness of films, and high vacuum deposition are limiting their applications. Recently, solution-processed networks of nanostructures such as carbon nanotubes (CNTs), graphene, and silver nanowires have attracted great attention as replacements. A low junction resistance between nanostructures is important for decreasing the sheet resistance. However, the junction resistances between CNTs and boundry resistances between graphene nanostructures are too high. The aspect ratios of silver nanowires are limited to ∼100, and silver is relatively expensive. Here, we show high-performance transparent electrodes with copper nanofiber networks by a low-cost and scalable electrospinning process. Copper nanofibers have ultrahigh aspect ratios of up to 100000 and fused crossing points with ultralow junction resistances, which result in high transmitance at low sheet resistance, e.g., 90% at 50 Ω/sq. The copper nanofiber networks also show great flexibility and stretchabilty. Organic solar cells using copper nanowire networks as transparent electrodes have a power efficiency of 3.0%, comparable to devices made with ITO electrodes. © 2010 American Chemical Society.

  16. The influence of anatase-rutile mixed phase and ZnO blocking layer on dye-sensitized solar cells based on TiO2nanofiberphotoanodes

    Science.gov (United States)

    2013-01-01

    High performance is expected in dye-sensitized solar cells (DSSCs) that utilize one-dimensional (1-D) TiO2 nanostructures owing to the effective electron transport. However, due to the low dye adsorption, mainly because of their smooth surfaces, 1-D TiO2 DSSCs show relatively lower efficiencies than nanoparticle-based ones. Herein, we demonstrate a very simple approach using thick TiO2 electrospun nanofiber films as photoanodes to obtain high conversion efficiency. To improve the performance of the DSCCs, anatase-rutile mixed-phase TiO2 nanofibers are achieved by increasing sintering temperature above 500°C, and very thin ZnO films are deposited by atomic layer deposition (ALD) method as blocking layers. With approximately 40-μm-thick mixed-phase (approximately 15.6 wt.% rutile) TiO2 nanofiber as photoanode and 15-nm-thick compact ZnO film as a blocking layer in DSSC, the photoelectric conversion efficiency and short-circuit current are measured as 8.01% and 17.3 mA cm−2, respectively. Intensity-modulated photocurrent spectroscopy and intensity-modulated photovoltage spectroscopy measurements reveal that extremely large electron diffusion length is the key point to support the usage of thick TiO2 nanofibers as photoanodes with very thin ZnO blocking layers to obtain high photocurrents and high conversion efficiencies. PMID:23286741

  17. Retraction: Gold nanoparticles immobilized on electrospun titanium dioxide nanofibers for catalytic reduction of 4-nitrophenol.

    Science.gov (United States)

    Cavusoglu, Halit; Buyukbekar, Burak Zafer; Sakalak, Huseyin; Kohsakowski, Sebastian

    2017-02-13

    This study involves the preparation and catalytic properties of anatase titanium dioxide nanofibers (TiO2 NFs) supported gold nanoparticles (Au NPs) using a model reaction based on the reduction of 4-nitrophenol (NP) into 4-aminophenol (AP) by sodium borohydride (NaBH4). The fabrication of surfactant-free Au NPs was performed using pulsed laser ablation in liquid (PLAL) technique. The TiO2 NFs were fabricated by a combination of electrospinning and calcination process using a solution containing poly(vinyl pyrolidone)(PVP) and titanium isopropoxide. The adsorption efficiency of laser-generated surfactant-free Au NPs to TiO2 NF supports as a function of pH was analyzed. Our results show that the electrostatic interaction mainly controls the adsorption of the nanoparticles. Au NPs/TiO2 NFs composite exhibited good catalytic activity for the reduction of 4-NP to 4-AP. The unique combination of these materials leads to the development of highly efficient catalysts. Our heterostructured nanocatalysts possibly form an efficient path to fabricate various metal NP/metal-oxide supported catalysts. Thus the applications of PLAL-noble metal NPs can widely broaden. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. The potential applications of fibrin-coated electrospun polylactide nanofibers in skin tissue engineering

    Czech Academy of Sciences Publication Activity Database

    Bačáková, Markéta; Musílková, Jana; Riedel, Tomáš; Stránská, D.; Brynda, Eduard; Žaloudková, Margit; Bačáková, Lucie

    2016-01-01

    Roč. 11, č. 2016 (2016), s. 771-789 E-ISSN 1178-2013 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:67985823 ; RVO:61389013 ; RVO:67985891 Keywords : electrospun nanofibers * nanocoating * skin tissue engineering * fibroblasts * fibrin Subject RIV: EI - Biotechnology ; Bionics; CD - Macromolecular Chemistry (UMCH-V); JI - Composite Materials (USMH-B) Impact factor: 4.300, year: 2016

  19. Preparation, Characterization and Sensitive Gas Sensing of Conductive Core-sheath TiO2-PEDOT Nanocables

    Directory of Open Access Journals (Sweden)

    Yu Lei

    2009-08-01

    Full Text Available Conductive core-sheath TiO2-PEDOT nanocables were prepared using electrospun TiO2 nanofibers as template, followed by vapor phase polymerization of EDOT. Various techniques were employed to characterize the sample. The results reveal that the TiO2 core has an average diameter of ~78 nm while the PEDOT sheath has a uniform thickness of ~6 nm. The as-prepared TiO2-PEDOT nanocables display a fast and reversible response to gaseous NO2 and NH3 with a limit of detection as low as 7 ppb and 675 ppb (S/N=3, respectively. This study provides a route for the synthesis of conductive nanostructures which show excellent performance for sensing applications.

  20. Synthesis and Process Optimization of Electrospun PEEK-Sulfonated Nanofibers by Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    Carlo Boaretti

    2015-07-01

    Full Text Available In this study electrospun nanofibers of partially sulfonated polyether ether ketone have been produced as a preliminary step for a possible development of composite proton exchange membranes for fuel cells. Response surface methodology has been employed for the modelling and optimization of the electrospinning process, using a Box-Behnken design. The investigation, based on a second order polynomial model, has been focused on the analysis of the effect of both process (voltage, tip-to-collector distance, flow rate and material (sulfonation degree variables on the mean fiber diameter. The final model has been verified by a series of statistical tests on the residuals and validated by a comparison procedure of samples at different sulfonation degrees, realized according to optimized conditions, for the production of homogeneous thin nanofibers.

  1. Alignment of Electrospun Nanofibers and Prediction of Electrospinning Linear Speed Using a Rotating Jet

    Directory of Open Access Journals (Sweden)

    M. Khamforoush

    2009-12-01

    Full Text Available Anew and effective electrospinning method has been developed for producing aligned polymer nanofibers. The conventional electrospinning technique has been modified to fabricate nanofibers as uniaxially aligned array. The key to the success of this technique is the creation of a rotating jet by using a cylindrical collector in which the needle tip is located at its center. The unique advantage of this method among the current methods is the ability of apparatus to weave continuously nanofibers in uniaxially aligned form. Fibers produced by this method are well-aligned, with several meters in length, and can be spread over a large area. We have employed a voltage range of (6-16 kV, a collector diameter in the range of 20-50 cm and various concentrations of PAN solutions ranging from 15 wt% to 19 wt %. The electrospun nanofibers could be conveniently formed onto the surface of any thin substrate such as glass sampling plate for subsequent treatments and other applications. Therefore, the linear speed of electrospinning process is determined experimentally as a function of cylindrical collector diameter, polymer concentration and field potential  difference.

  2. Comparison of cell behavior on pva/pva-gelatin electrospun nanofibers with random and aligned configuration

    Science.gov (United States)

    Huang, Chen-Yu; Hu, Keng-Hsiang; Wei, Zung-Hang

    2016-12-01

    Electrospinning technique is able to create nanofibers with specific orientation. Poly(vinyl alcohol) (PVA) have good mechanical stability but poor cell adhesion property due to the low affinity of protein. In this paper, extracellular matrix, gelatin is incorporated into PVA solution to form electrospun PVA-gelatin nanofibers membrane. Both randomly oriented and aligned nanofibers are used to investigate the topography-induced behavior of fibroblasts. Surface morphology of the fibers is studied by optical microscopy and scanning electron microscopy (SEM) coupled with image analysis. Functional group composition in PVA or PVA-gelatin is investigated by Fourier Transform Infrared (FTIR). The morphological changes, surface coverage, viability and proliferation of fibroblasts influenced by PVA and PVA-gelatin nanofibers with randomly orientated or aligned configuration are systematically compared. Fibroblasts growing on PVA-gelatin fibers show significantly larger projected areas as compared with those cultivated on PVA fibers which p-value is smaller than 0.005. Cells on PVA-gelatin aligned fibers stretch out extensively and their intracellular stress fiber pull nucleus to deform. Results suggest that instead of the anisotropic topology within the scaffold trigger the preferential orientation of cells, the adhesion of cell membrane to gelatin have substantial influence on cellular behavior.

  3. Uniaxially aligned electrospun all-cellulose nanocomposite nanofibers reinforced with cellulose nanocrystals: scaffold for tissue engineering.

    Science.gov (United States)

    He, Xu; Xiao, Qiang; Lu, Canhui; Wang, Yaru; Zhang, Xiaofang; Zhao, Jiangqi; Zhang, Wei; Zhang, Ximu; Deng, Yulin

    2014-02-10

    Uniaxially aligned cellulose nanofibers with well oriented cellulose nanocrystals (CNCs) embedded were fabricated via electrospinning using a rotating drum as the collector. Scanning electron microscope (SEM) images indicated that most cellulose nanofibers were uniaxially aligned. The incorporation of CNCs into the spinning dope resulted in more uniform morphology of the electrospun cellulose/CNCs nanocomposite nanofibers (ECCNN). Polarized light microscope (PLM) and transmission electron microscope (TEM) showed that CNCs dispersed well in ECCNN nonwovens and achieved considerable orientation along the long axis direction. This unique hierarchical microstructure of ECCNN nonwovens gave rise to remarkable enhancement of their physical properties. By incorporating 20% loading (in weight) of CNCs, the tensile strength and elastic modulus of ECCNN along the fiber alignment direction were increased by 101.7 and 171.6%, respectively. Their thermal stability was significantly improved as well. In addition, the ECCNN nonwovens were assessed as potential scaffold materials for tissue engineering. It was elucidated from MTT tests that the ECCNN were essentially nontoxic to human cells. Cell culture experiments demonstrated that cells could proliferate rapidly not only on the surface but also deep inside the ECCNN. More importantly, the aligned nanofibers of ECCNN exhibited a strong effect on directing cellular organization. This feature made the scaffold particularly useful for various artificial tissues or organs, such as blood vessel, tendon, nerve, and so on, in which cell orientation was crucial for their performance.

  4. Development of Omniphobic Desalination Membranes Using a Charged Electrospun Nanofiber Scaffold.

    Science.gov (United States)

    Lee, Jongho; Boo, Chanhee; Ryu, Won-Hee; Taylor, André D; Elimelech, Menachem

    2016-05-04

    In this study, we present a facile and scalable approach to fabricate omniphobic nanofiber membranes by constructing multilevel re-entrant structures with low surface energy. We first prepared positively charged nanofiber mats by electrospinning a blend polymer-surfactant solution of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and cationic surfactant (benzyltriethylammonium). Negatively charged silica nanoparticles (SiNPs) were grafted on the positively charged electrospun nanofibers via dip-coating to achieve multilevel re-entrant structures. Grafted SiNPs were then coated with fluoroalkylsilane to lower the surface energy of the membrane. The fabricated membrane showed excellent omniphobicity, as demonstrated by its wetting resistance to various low surface tension liquids, including ethanol with a surface tension of 22.1 mN/m. As a promising application, the prepared omniphobic membrane was tested in direct contact membrane distillation to extract water from highly saline feed solutions containing low surface tension substances, mimicking emerging industrial wastewaters (e.g., from shale gas production). While a control hydrophobic PVDF-HFP nanofiber membrane failed in the desalination/separation process due to low wetting resistance, our fabricated omniphobic membrane exhibited a stable desalination performance for 8 h of operation, successfully demonstrating clean water production from the low surface tension feedwater.

  5. Polyaniline-nylon-6 electrospun nanofibers for headspace adsorptive microextraction.

    Science.gov (United States)

    Bagheri, Habib; Aghakhani, Ali

    2012-02-03

    A headspace adsorptive microextraction technique was developed using a novel polyaniline-nylon-6 (PANI-N6) nanofiber sheet, fabricated by electrospinning. The homogeneity and the porosity of the prepared PANI-N6 sheet were studied using the scanning electron microscopy (SEM) and nanofibers diameters were found to be around 200 nm. The novel nanofiber sheet was examined as an extracting medium to isolate some selected chlorobenzenes (CBs), as model compounds, from aquatic media. The extracted analytes were desorbed using μL-amounts of solvent and eventually an aliquot of extractant was injected into gas chromatography-mass spectrometry (GC-MS). Various parameters affecting the extraction and desorption processes were optimized. The developed method proved to be convenient and offers sufficient sensitivity and a good reproducibility. Limits of detection achieved for CBs with the developed analytical procedure ranged from 19 to 33 ng L(-1), while limits of quantification were from 50 to 60 ng L(-1). The relative standard deviations (RSD) at a concentration level of 0.1 ng mL(-1) and 1 ng mL(-1) were in the range of 8-14% and 5-11% (n=3), respectively. The calibration curves of analytes were investigated in the range of 50-1000 ng L(-1) and R(2) between 0.9739 and 0.9932 were obtained. The developed method was successfully applied to the extraction of selected CBs from tap and river water samples. The relative recovery (RR) percentage obtained for the spiked real water samples at 0.1 ng mL(-1) and 1 ng mL(-1) level were 93-103% and 95-104%, respectively. The whole procedure showed to be conveniently applicable and quite easy to handle. Copyright © 2011 Elsevier B.V. All rights reserved.

  6. Antimicrobial filtration with electrospun poly(vinyl alcohol) nanofibers containing benzyl triethylammonium chloride: Immersion, leaching, toxicity, and filtration tests.

    Science.gov (United States)

    Park, Jeong-Ann; Kim, Song-Bae

    2017-01-01

    Antimicrobial electrospun poly(vinyl alcohol) (PVA) nanofibers were synthesized by impregnating benzyl triethylammonium chloride (BTEAC) as an antimicrobial agent into PVA nanofibers. The BTEAC-PVA nanofibers were heat-methanol treated during the preparation for various tests. The BTEAC-PVA nanofibers became more hydrophilic than the PVA nanofibers due to incorporation of BTEAC. Through heat-methanol treatment, thermal property, crystallinity, and water stability of BTEAC-PVA nanofibers were improved considerably. The immersion test shows that heat-methanol treatment has an advantage over heat treatment to maintain BTEAC content in BTEAC-PVA nanofibers. The acute toxicity test demonstrates that the 24-h EC50 and 48-h EC50 values (EC50 = median effective concentration) of BTEAC to Daphnia magna were 113 and 90 mg/L, respectively. The leaching test indicates that the BTEAC concentration leached from BTEAC-PVA nanofibers was far below the concentration affecting the immobilization of D. magna. For antimicrobial filtration tests, the BTEAC-PVA nanofibers were deposited onto glass fiber filter. The antimicrobial filtration test was conducted against bacteria (Escherichia coli, Staphylococcus aureus) and bacteriophages (MS2, PhiX174), demonstrating that the BTEAC-PVA nanofibers could enhance the removal of E. coli and S. aureus considerably but not the removal of MS2 and PhiX174 under dynamic flow conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. The quintuple-shape memory effect in electrospun nanofiber membranes

    Science.gov (United States)

    Zhang, Fenghua; Zhang, Zhichun; Liu, Yanju; Lu, Haibao; Leng, Jinsong

    2013-08-01

    Shape memory fibrous membranes (SMFMs) are an emerging class of active polymers, which are capable of switching from a temporary shape to their permanent shape upon appropriate stimulation. Quintuple-shape memory membranes based on the thermoplastic polymer Nafion, with a stable fibrous structure, are achieved via electrospinning technology, and possess a broad transition temperature. The recovery of multiple temporary shapes of electrospun membranes can be triggered by heat in a single triple-, quadruple-, quintuple-shape memory cycle, respectively. The fiber morphology and nanometer size provide unprecedented design flexibility for the adjustable morphing effect. SMFMs enable complex deformations at need, having a wide potential application field including smart textiles, artificial intelligence robots, bio-medical engineering, aerospace technologies, etc in the future.

  8. Electrospun biodegradable nanofiber nonwovens for controlled release of proteins.

    Science.gov (United States)

    Maretschek, Sascha; Greiner, Andreas; Kissel, Thomas

    2008-04-21

    Electrospinning of emulsions composed of an organic poly(l-lactide) solution and an aqueous protein solution yielded protein containing nanofiber nonwovens (NNs) having a mean fiber diameter of approximately 350 nm. Cytochrome C was chosen as a hydrophilic model protein for encapsulation. SEM imaging and gas adsorption measurements were carried out to determine morphology and surface characteristics of the different nanofiber nonwovens. Transmission electron microscopy was used to clarify the localization of the protein within the NN. PLLA NNs exhibited a highly hydrophobic surface which led to a slow wetting. It was shown that the protein release was dependent on the surface tension of the release medium. Electrospinning of emulsions consisting of an organic solution of PLLA and an aqueous solution of hydrophilic polymers yielded fibers composed of a polymer blend. The resulting NNs exhibited a less hydrophobic surface, which gave us the opportunity to tailor the release profile via this technology. Furthermore it was investigated how the addition of different amounts of hydrophilic polymer to the aqueous phase influenced the morphology of the resulting NNs.

  9. Mebeverine-loaded electrospun nanofibers: physicochemical characterization and dissolution studies.

    Science.gov (United States)

    Illangakoon, Upulitha Eranka; Nazir, Tahir; Williams, Gareth R; Chatterton, Nicholas P

    2014-01-01

    Both fast dissolving and sustained release drug delivery systems (DDSs) comprising mebeverine hydrochloride (MB-HCl) embedded in either povidone (PVP) K60 or Eudragit(®) L 100-55 nanofibers have been prepared by electrospinning. The fibers are found to have cylindrical morphologies with smooth surfaces, except at high drug loadings that appear to induce surface roughness (PVP) or fragmentation (Eudragit). There is a general increase in fiber diameter with drug loading. Differential scanning calorimetry and X-ray diffraction demonstrate that the drug exists in an amorphous state in the fibers. Infrared spectroscopy data indicate that the drug has good compatibility with the polymer, whereas nuclear magnetic resonance spectroscopy and high-performance liquid chromatography analyses confirmed that the MB-HCl was not degraded during the spinning process. In vitro dissolution tests of the PVP fiber mats show them to dissolve within 10 s, an improved dissolution profile over the pure drug. The Eudragit fibers show pH-dependent drug release profiles, with only very limited release at pH 2.0 but sustained release over approximately 8 h at pH 6.8. The Eudragit nanofibers have the potential to be developed as oral DDSs for localized drug release in the intestinal tract, whereas the PVP materials may find the application as buccal delivery systems or suppositories. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

  10. Electrospun core-shell nanofibers derived Fe-S/N doped carbon material for oxygen reduction reaction

    Science.gov (United States)

    Guo, Junxia; Niu, Qijian; Yuan, Yichun; Maitlo, Inamullh; Nie, Jun; Ma, Guiping

    2017-09-01

    One-dimensional (1D) nanomaterials have gained attention in energy conversion, storage, and catalyst due to the unique physical and chemical properties. Electrospinning is a kind of simple, versatile, and cost-effective technology to fabricate 1D functional nanofibers. Herein, electrospun polyacrylonitrile (PAN), melamine, and ferric chloride hexahydrate (FeCl3·6H2O) composite nanofibers are used as template, and polythiophene (PT) are prepared by photopolymerization technology on the surface of electrospun nanofibers as shell part of fibers. Then, the core-shell nanofibers are pyrolyzed and converted into Fe-S/N-C nanofibers, which can be used as catalysts for ORR due to the metal and S-/N-codoped structure and unique 1D structure which provided facile pathways for efficient mass transport and charge transfer. The ORR electrocatalytic ability of Fe-S/N-C nanofibers is tested and present excellent property, especially in stability and methanol crossover. The electrocatalytic ability of sample is comparable to that of 20 wt% Pt/C benchmarks. These results offer an easy pathway for exploring metal-heteroatom-codoped carbon nanofibers applicable for ORR catalyst.

  11. Highly sensitive and ultrafast response surface acoustic wave humidity sensor based on electrospun polyaniline/poly(vinyl butyral) nanofibers.

    Science.gov (United States)

    Lin, Qianqian; Li, Yang; Yang, Mujie

    2012-10-20

    Polyaniline (PANi) composite nanofibers were deposited on surface acoustic wave (SAW) resonator with a central frequency of 433 MHz to construct humidity sensors. Electrospun nanofibers of poly(methyl methacrylate), poly(vinyl pyrrolidone), poly(ethylene oxide), poly(vinylidene fluoride), poly(vinyl butyral) (PVB) were characterized by scanning electron microscopy, and humidity response of corresponding SAW humidity sensors were investigated. The results indicated that PVB was suitable as a matrix to form nanofibers with PANi by electrospinning (ES). Electrospun PANi/PVB nanofibers exhibited a core-sheath structure as revealed by transmittance electron microscopy. Effects of ES collection time on humidity response of SAW sensor based on PANi/PVB nanofibers were examined at room temperature. The composite nanofiber sensor exhibited very high sensitivity of ~75kHz/%RH from 20 to 90%RH, ultrafast response (1s and 2s for humidification and desiccation, respectively) and good sensing linearity. Furthermore, the sensor could detect humidity as low as 0.5%RH, suggesting its potentials for low humidity detection. Attempts were done to explain the attractive humidity sensing performance of the sensor by considering conductivity, hydrophilicity, viscoelasticity and morphology of the polymer composite nanofibers. Copyright © 2012 Elsevier B.V. All rights reserved.

  12. Influences of Silver-Doping on the Crystal Structure, Morphology and Photocatalytic Activity of TiO2 Nanofibers

    DEFF Research Database (Denmark)

    Barakat, Nasser A. M.; Kanjwal, Muzafar Ahmed; Al-Deyab, Salem S.

    2011-01-01

    morphology was observed as increase the silver content caused to decrease the aspect ratio, i.e. producing nanorods rather nanofibers. However, silver-doping leads to modify the surface roughness. Study of the photocatalytic degradation of methylene blue dye clarified that in-crease the silver content...

  13. Electrospun magnetically separable calcium ferrite nanofibers for photocatalytic water purification

    Science.gov (United States)

    EL-Rafei, A. M.; El-Kalliny, Amer S.; Gad-Allah, Tarek A.

    2017-04-01

    Three-dimensional random calcium ferrite, CaFe2O4, nanofibers (NFs) were successfully prepared via the electrospinning method. The effect of calcination temperature on the characteristics of the as-spun NFs was investigated. X-ray diffraction analysis showed that CaFe2O4 phase crystallized as a main phase at 700 °C and as a sole phase at 1000 °C. Field emission scanning electron microscopy emphasized that CaFe2O4 NFs were fabricated with diameters in the range of 50-150 nm and each fiber was composed of 20-50 nm grains. Magnetic hysteresis loops revealed superparamagnetic behavior for the prepared NFs. These NFs produced active hydroxyl radicals under simulated solar light irradiation making them recommendable for photocatalysis applications in water purification. In the meantime, these NFs can be easily separated from the treated water by applying an external magnetic field.

  14. In vitro evaluation of the effects of electrospun PCL nanofiber mats containing the microalgae Spirulina (Arthrospira) extract on primary astrocytes.

    Science.gov (United States)

    Kim, Sung Hoon; Shin, Chungwhan; Min, Seul Ki; Jung, Sang-Myung; Shin, Hwa Sung

    2012-02-01

    The blue-green microalgae, Spirulina, a harmless food and pharmaceutical additive, has several bioactive compounds that have therapeutic functions. Polycaprolactone (PCL) is a biocompatible and biodegradable polymer that has widely been used for tissue engineering. The electrospun PCL nanofiber containing Spirulina (PCL-Spirulina) was fabricated and tested as a potential extracellular matrix material for a culture of primary astrocytes, which play important roles in CNS injured systems. Spirulina extract was observed to increase growth and metabolic activity of rat primary astrocytes without any harm once added to the culture media. However, PCL-Spirulina nanofiber was proven to alleviate astrocyte activity. Through this research and to the best of our knowledge, we first suggest a novel composite nanomaterial, an electrospun PCL-Spirulina nanofiber that could be used to treat CNS injured systems. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Studies on single polymer composites of poly(methyl methacrylate) reinforced with electrospun nanofibers with a focus on their dynamic mechanical properties

    CSIR Research Space (South Africa)

    Matabola, KP

    2011-07-01

    Full Text Available The dynamic mechanical properties of single polymer composites of poly(methyl methacrylate) (PMMA) reinforced with electrospun PMMA nanofibers of different diameters are reported. The effect of electrospinning parameters on the morphology...

  16. Role of ITO nanoparticles embedded into electrospun ITO nanofibers

    Science.gov (United States)

    Yoon, Sangcheol; Kim, Hyebin; Cha, Seung-Jae; Shin, Eun-Sol; Noh, Yong-Young; Hong, Sung-Jei; Park, Byoungchoo; Hwang, Inchan

    2017-11-01

    Both crystallization and molecular density are significant to achieve high electrical conductivity of transparent electrodes. Herein, we investigated the embedding effects of indium tin oxide (ITO) nanoparticles (NPs) into ITO nanofibers (NFs) synthesized by utilizing an electrospinning technique from ITO precursor solutions. We found that the ITO NPs might act as nucleation seeds that initiate crystallization of ITO, evidenced by flake-like morphologies which cannot be observed without ITO NPs. XRD measurements reveal that the ITO is crystalline with a higher degree and the size of ITO crystallites increases in the presence of ITO NPs embedded into NFs. Embedding ITO NPs leads to the formation of short fibers, but there is still large space between fibers as they are vertically stacked in the films, resulting in low electrical conductivity. Interestingly, a high ratio of ITO NPs enhances the electrical conductivity, as compared to a low ratio, which we attribute to the high fiber density on substrates due to the formation of shorter ITO NFs. Our results highlight that the ITO NPs influence not only the ITO crystallization but also the lengths of NFs. High electrical conductivity of NF films can be obtained by a high degree of crystallization and the optimum NF length that reduces spaces between NFs in the films.

  17. Effect of polymer concentration on the morphology and mechanical characteristics of electrospun cellulose acetate and poly (vinyl chloride nanofiber mats

    Directory of Open Access Journals (Sweden)

    Bethwel Tarus

    2016-09-01

    Full Text Available Cellulose Acetate (CA and Poly (Vinyl Chloride (PVC nanofiber mats were electrospun into nanofibers. The morphology and mechanical properties of nanofiber mats were evaluated versus different solution concentrations. Solutions were prepared in mixed solvent systems of 2:1 (w/w Acetone/N,N-Dimethylacetamide (DMAc and 3:2 (w/w Acetone/N,N-Dimethylformamide (DMF for CA and 1:1 (w/w Tetrahydrofuran/DMF for PVC. Scanning electron microscopy (SEM images revealed that a beaded fibrous structure could be electrospun beginning at 10% CA in both Acetone/DMAc and Acetone/DMF solvent systems. The experimental results showed that smooth fibers were achievable at 14% CA in Acetone/DMAc and at 16% CA in Acetone/DMF solvent systems. For PVC, beaded fibers were formed at 12% PVC and smooth fibers were formed beginning at 14% PVC. Tensile strength tests showed that mechanical properties of the nonaligned nanofiber mats were influenced by solution concentration. With increasing solution concentration, the tensile strengths, break strains and initial moduli of the CA nanofiber mats increased. The effect of solution concentration on the tensile strengths of nanofiber mats was quite significant while it did not have any considerable effect on the tensile properties of the cast films.

  18. Gas diffusion electrode based on electrospun Pani/CNF nanofibers hybrid for proton exchange membrane fuel cells (PEMFC) applications

    Science.gov (United States)

    Hezarjaribi, M.; Jahanshahi, M.; Rahimpour, A.; Yaldagard, M.

    2014-03-01

    A novel hybrid system has been investigated based on polyaniline/carbon nanofiber (Pani/CNF) electrospun nanofibers for modification of gas diffusion electrode (GDE) in proton exchange membrane fuel cells (PEMFC). Pani/CNF hybrid nanofibers were synthesized directly on carbon paper by electrospinning method. For preparation of catalyst ink, 20 wt.% Pt/C electrocatalyst with a platinum loading of 0.4 mg cm-2 was prepared by polyol technique. SEM studies applied for morphological study of the modified GDE with hybrid nanofibers. This technique indicated that the electrospun nanofibers had a diameter of roughly 100 nm. XRD patterns also showed that the average size of Pt nanoparticles was about 2 nm. Subsequently, comparison of the hybrid electrode electrochemical behavior and 20 wt.% Pt/C commercial one was studied by cyclic voltammetry experiment. The electrochemical data indicated that the hybrid electrode exhibited higher current density (about 15 mA cm-2) and ESA (160 m2 gr-1) than commercial Pt/C with amount of about 10 mA cm-2 and 114 m2 gr-1, respectively. The results herein demonstrate that Pani/CNF nanofibers can be used as a good alternative electrode material for PEMFCs.

  19. Gas diffusion electrode based on electrospun Pani/CNF nanofibers hybrid for proton exchange membrane fuel cells (PEMFC) applications

    Energy Technology Data Exchange (ETDEWEB)

    Hezarjaribi, M.; Jahanshahi, M., E-mail: mjahan@nit.ac.ir; Rahimpour, A.; Yaldagard, M.

    2014-03-01

    A novel hybrid system has been investigated based on polyaniline/carbon nanofiber (Pani/CNF) electrospun nanofibers for modification of gas diffusion electrode (GDE) in proton exchange membrane fuel cells (PEMFC). Pani/CNF hybrid nanofibers were synthesized directly on carbon paper by electrospinning method. For preparation of catalyst ink, 20 wt.% Pt/C electrocatalyst with a platinum loading of 0.4 mg cm{sup −2} was prepared by polyol technique. SEM studies applied for morphological study of the modified GDE with hybrid nanofibers. This technique indicated that the electrospun nanofibers had a diameter of roughly 100 nm. XRD patterns also showed that the average size of Pt nanoparticles was about 2 nm. Subsequently, comparison of the hybrid electrode electrochemical behavior and 20 wt.% Pt/C commercial one was studied by cyclic voltammetry experiment. The electrochemical data indicated that the hybrid electrode exhibited higher current density (about 15 mA cm{sup −2}) and ESA (160 m{sup 2} gr{sup −1}) than commercial Pt/C with amount of about 10 mA cm{sup −2} and 114 m{sup 2} gr{sup −1}, respectively. The results herein demonstrate that Pani/CNF nanofibers can be used as a good alternative electrode material for PEMFCs.

  20. Electrospun Nanofibers Made of Silver Nanoparticles, Cellulose Nanocrystals, and Polyacrylonitrile as Substrates for Surface-Enhanced Raman Scattering.

    Science.gov (United States)

    Ren, Suxia; Dong, Lili; Zhang, Xiuqiang; Lei, Tingzhou; Ehrenhauser, Franz; Song, Kunlin; Li, Meichun; Sun, Xiuxuan; Wu, Qinglin

    2017-01-14

    Nanofibers with excellent activities in surface-enhanced Raman scattering (SERS) were developed through electrospinning precursor suspensions consisting of polyacrylonitrile (PAN), silver nanoparticles (AgNPs), silicon nanoparticles (SiNPs), and cellulose nanocrystals (CNCs). Rheology of the precursor suspensions, and morphology, thermal properties, chemical structures, and SERS sensitivity of the nanofibers were investigated. The electrospun nanofibers showed uniform diameters with a smooth surface. Hydrofluoric (HF) acid treatment of the PAN/CNC/Ag composite nanofibers (defined as p-PAN/CNC/Ag) led to rougher fiber surfaces with certain pores and increased mean fiber diameters. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results confirmed the existence of AgNPs that were formed during heat and HF acid treatment processes. In addition, thermal stability of the electrospun nanofibers increased due to the incorporation of CNCs and AgNPs. The p-PAN/CNC/Ag nanofibers were used as a SERS substrate to detect p-aminothiophenol (p-ATP) probe molecule. The results show that this substrate exhibited high sensitivity for the p-ATP probe detection.

  1. Electrospun Nanofibers Made of Silver Nanoparticles, Cellulose Nanocrystals, and Polyacrylonitrile as Substrates for Surface-Enhanced Raman Scattering

    Science.gov (United States)

    Ren, Suxia; Dong, Lili; Zhang, Xiuqiang; Lei, Tingzhou; Ehrenhauser, Franz; Song, Kunlin; Li, Meichun; Sun, Xiuxuan; Wu, Qinglin

    2017-01-01

    Nanofibers with excellent activities in surface-enhanced Raman scattering (SERS) were developed through electrospinning precursor suspensions consisting of polyacrylonitrile (PAN), silver nanoparticles (AgNPs), silicon nanoparticles (SiNPs), and cellulose nanocrystals (CNCs). Rheology of the precursor suspensions, and morphology, thermal properties, chemical structures, and SERS sensitivity of the nanofibers were investigated. The electrospun nanofibers showed uniform diameters with a smooth surface. Hydrofluoric (HF) acid treatment of the PAN/CNC/Ag composite nanofibers (defined as p-PAN/CNC/Ag) led to rougher fiber surfaces with certain pores and increased mean fiber diameters. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) results confirmed the existence of AgNPs that were formed during heat and HF acid treatment processes. In addition, thermal stability of the electrospun nanofibers increased due to the incorporation of CNCs and AgNPs. The p-PAN/CNC/Ag nanofibers were used as a SERS substrate to detect p-aminothiophenol (p-ATP) probe molecule. The results show that this substrate exhibited high sensitivity for the p-ATP probe detection. PMID:28772428

  2. Bacterial response to different surface chemistries fabricated by plasma polymerization on electrospun nanofibers.

    Science.gov (United States)

    Abrigo, Martina; Kingshott, Peter; McArthur, Sally L

    2015-12-06

    Control over bacterial attachment and proliferation onto nanofibrous materials constitutes a major challenge for a variety of applications, including filtration membranes, protective clothing, wound dressings, and tissue engineering scaffolds. To develop effective devices, the interactions that occur between bacteria and nanofibers with different morphological and physicochemical properties need to be investigated. This paper explores the influence of fiber surface chemistry on bacterial behavior. Different chemical functionalities were generated on the surface of electrospun polystyrene nanofibers through plasma polymerization of four monomers (acrylic acid, allylamine, 1,7-octadiene, and 1,8-cineole). The interactions of Escherichia coli with the surface modified fibers were investigated through a combination of scanning electron microscopy and confocal laser scanning microscopy. Fiber wettability, surface charge, and chemistry were found to affect the ability of bacterial cells to attach and proliferate throughout the nanofiber meshes. The highest proportion of viable cells attachment occurred on the hydrophilic amine rich coating, followed by the hydrophobic octadiene. The acrylic acid coating rich in carboxyl groups showed a significantly lower attraction of bacterial cells. The 1,8-cineole retained the antibacterial activity of the monomer, resulting with a high proportion of dead isolated cells attached onto the fibers. Results showed that the surface chemistry properties of nanofibrous membranes can be strategically tuned to control bacterial behavior.

  3. Electrospun nanofibers as a tool for architecture control in engineered cardiac tissue.

    Science.gov (United States)

    Orlova, Yuliya; Magome, Nobuyuki; Liu, Li; Chen, Yong; Agladze, Konstantin

    2011-08-01

    This paper presents an in vitro system for cardiac tissue engineering based on cardiomyocytes cultured on electrospun polymethylglutarimide (PMGI) nanofibrous meshes either imprinted on solid substrate or suspended in space. Special care was taken over the ability to control the tissue architecture. The electrospinning process allowed nano-scale diameter PMGI fibers with different positioning density to be collected in a random or in an aligned way that defines the general configuration of the mesh. Micro-imprinted on solid substrate nanofibers guarantee aligned cell growth, when the distance between them is 30 μm or less. Suspended in 3D space, nanofibers define the overall architecture of the tissue, depending on orientation and positioning density of the nanofibers. As a result, cardiac cells proliferated into contractile tissue filaments, open-worked tissue meshes and continuous anisotropic cell sheets. Alignment of the cells was characterized by elongation of the cell shape and orientation of the α-actin filaments supported by the FFT data. The advantage of this method is its ability to maintain both three-dimensionality and structural anisotropy. Copyright © 2011 Elsevier Ltd. All rights reserved.

  4. Aligned electrospun nanofibers as proton conductive channels through thickness of sulfonated poly (phthalazinone ether sulfone ketone) proton exchange membranes

    Science.gov (United States)

    Gong, Xue; He, Gaohong; Wu, Yao; Zhang, Shikai; Chen, Bo; Dai, Yan; Wu, Xuemei

    2017-08-01

    A novel approach is proposed to fabricate sulfonated poly (phthalazinone ether sulfone ketone) (SPPESK) proton exchange membranes with ordered through-plane electrospinning nanofibers, which provide nano-scale through-plane proton conductive channels along the thickness direction of the membranes, aiming to satisfy the challenging requirement of high through-plane proton conductivity in fuel cell operations. Induced by electrostatic attraction of strong electric field, the negatively charged sulfonic acid groups tend to aggregate towards surface of the electrospun fibers, which is evidenced by TEM and SAXS and further induces aggregation of the sulfonic acid groups in the SPPESK inferfiber voids filler along the surface of the nanofibers. The aligned electrospun nanofibers carries long-range ionic clusters along the thickness direction of the membrane and results in much higher total through-plane conductivity in the thickness aligned electrospun membranes, nearly twice as much as that of the cast SPPESK membrane. With smooth treatment, the thickness aligned electrospun SPPESK membranes exhibit higher single cell power density and tensile strength as compared with Nafion 115 (around 1.2 and 1.5 folds, respectively). Such a design of thickness aligned nano-size proton conductive channels provide feasibility for high performance non-fluorinated PEMs in fuel cell applications.

  5. Process Optimization and Emperical Modelling for Electrospun Polyacrylonitrile (PAN) Nanofiber Precursor of Carbon nanofibers

    NARCIS (Netherlands)

    Gu, S.Y.; Gu, S.; Ren, J.; Vancso, Gyula J.

    2005-01-01

    Ultrafine fibers were spun from polyacrylonitrile (PAN)/N,N-dimethyl formamide (DMF) solution as a precursor of carbon nanofibers using a homemade electrospinning set-up. Fibers with diameter ranging from 200 nm to 1200 nm were obtained. Morphology of fibers and distribution of fiber diameter were

  6. Electrospun magnetically separable calcium ferrite nanofibers for photocatalytic water purification

    Energy Technology Data Exchange (ETDEWEB)

    EL-Rafei, A.M., E-mail: am.amin@nrc.sci.eg [Refractories, Ceramics and Building Materials Department, National Research Centre, 33 EL Bohouth St. (former EL Tahrir St.), P.O. 12622, Dokki, Giza (Egypt); El-Kalliny, Amer S.; Gad-Allah, Tarek A. [Water Pollution Research Department, National Research Centre, 33 EL Bohouth St. (former EL Tahrir St.), P.O. 12622, Dokki, Giza (Egypt)

    2017-04-15

    Three-dimensional random calcium ferrite, CaFe{sub 2}O{sub 4}, nanofibers (NFs) were successfully prepared via the electrospinning method. The effect of calcination temperature on the characteristics of the as-spun NFs was investigated. X-ray diffraction analysis showed that CaFe{sub 2}O{sub 4} phase crystallized as a main phase at 700 °C and as a sole phase at 1000 °C. Field emission scanning electron microscopy emphasized that CaFe{sub 2}O{sub 4} NFs were fabricated with diameters in the range of 50–150 nm and each fiber was composed of 20–50 nm grains. Magnetic hysteresis loops revealed superparamagnetic behavior for the prepared NFs. These NFs produced active hydroxyl radicals under simulated solar light irradiation making them recommendable for photocatalysis applications in water purification. In the meantime, these NFs can be easily separated from the treated water by applying an external magnetic field. - Highlights: • Three-dimensional porous random CaFe{sub 2}O{sub 4} NFs were successfully produced via electrospinning method. • These NFs exhibited typical superparamagnetic behavior for the ferromagnetic materials. • The low band-gap energy of these NFs (~1.6 eV) allows them to absorb a wide range of the solar spectrum. • These NFs can produce the active {sup •} OH under solar light and can be recovered easily by applying an external magnetic field. • These NFs can be used solely as magnetically separable photocatalyst or as magnetic additive for another photocatalyst.

  7. Preparation and Characterization of Soluble Eggshell Membrane Protein/PLGA Electrospun Nanofibers for Guided Tissue Regeneration Membrane

    Directory of Open Access Journals (Sweden)

    Jun Jia

    2012-01-01

    Full Text Available Guided tissue regeneration (GTR is a widely used method in periodontal therapy, which involves the placement of a barrier membrane to exclude migration of epithelium and ensure repopulation of periodontal ligament cells. The objective of this study is to prepare and evaluate a new type of soluble eggshell membrane protein (SEP/poly (lactic-co-glycolic acid (PLGA nanofibers using electrospinning method for GTR membrane application. SEP/PLGA nanofibers were successfully prepared with various blending ratios. The morphology, chemical composition, surface wettability, and mechanical properties of the nanofibers were characterized using scanning electron microscopy (SEM, contact angle measurement, Fourier transform-infrared spectroscopy (FTIR, and a universal testing machine. L-929 fibroblast cells were used to evaluate the biocompatibility of SEP/PLGA nanofibers and investigate the interaction between cells and nanofibers. Results showed that the SEP/PLGA electrospun membrane was composed of uniform, bead-free nanofibers, which formed an interconnected porous network structure. Mechanical property of SEP has been greatly improved by the addition of PLGA. The biological study results showed that SEP/PLGA nanofibers could enhance cell attachment, spreading, and proliferation. The study indicated the potential of SEP/PLGA nanofibers for GTR application and provided a basis for future optimization.

  8. Hyperbranched-polyol-tethered poly (amic acid) electrospun nanofiber membrane with ultrahigh adsorption capacity for boron removal

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Zhe; Wu, Zhongyu; Zhang, Yufeng; Meng, Jianqiang, E-mail: jianqiang.meng@hotmail.com

    2017-04-30

    Highlights: • Electrospun nanofiber membranes were grafted with hyperbranched polyols. • The membrane had a maximum boron uptake of 5.68 mmol/g. • The membrane could adsorb 0.82 mmol/g boron from a 5 mg/L solution in 15 min. • The membrane obeyed the Langmuir and the pseudo-first-order kinetic model. • The regeneration efficiency remained over 90% after 10 cycled uses. - Abstract: The development of efficient adsorbents with high sorption capacity remains as a challenge for the removal of micropollutants occurred globally in water resources. In this work, poly (amic acid) (PAA) electrospun nanofiber membranes grafted with hyperbranched polyols were synthesized and used for boron removal. The PAA nanofiber was reacted with hyperbranched polyethylenimine (HPEI) and further with glycidol to introduce the vicinal hydroxyl groups. The chemical composition and surface characteristics of the obtained PAA-g-PG membranes were evaluated by FESEM, FTIR, XPS and water contact angles (WCA) measurements. The boron adsorption thermodynamics and kinetics were investigated systematically. The results showed that the PAA nanofiber spun from concentration of 15% had uniform morphology and narrow diameter distribution. The PAA-g-PG nanofiber membrane had a maximum boron uptake of 5.68 mmol/g and could adsorb 0.82 mmol/g boron from a 5 mg/L solution in 15 min. Both the high surface area of nanofibers and the hyperbranched structure should contribute to the high boron uptake and high adsorption rate. The nanofiber membrane obeyed the Langmuir adsorption model and the pseudo-first-order kinetic model. The regeneration efficiency of the nanofiber membrane remained 93.9% after 10 cycled uses, indicating good regenerability of the membrane.

  9. Improved response time of thick liquid crystal device by using electrospun nanofiber

    Science.gov (United States)

    Duong, Toan Quoc; Kobayashi, Hiroaki; Inoue, Yo; Moritake, Hiroshi

    2017-06-01

    In this study, we report the improved response time of a thick nematic liquid crystal (LC) device by using an electrospun nanofiber (NF). We investigated the influence of NF characteristics including polymer material, NF volume ratio, and diameter, on the electrical characteristic of the NF/LC composite. A conventional LC device and a polymer-stabilized liquid crystal (PSLC) device were fabricated to compare their electrical characteristics with those of the NF/LC composite. The rise time, decay time, and threshold voltage of these LC devices are determined by measuring the dielectric permittivity. In comparison with the conventional LC device, the decay time of the NF/LC device is significantly improved. Compared with the PSLC device with the same thickness, the NF/LC device shows a lower threshold voltage while exhibiting the same decay time. Finally, we demonstrated the markedly improved response time of a THz phase shifter by using an NF/LC composite.

  10. Preparation of Electrospun Nanocomposite Nanofibers of Polyaniline/Poly(methyl methacrylate with Amino-Functionalized Graphene

    Directory of Open Access Journals (Sweden)

    Hanan Abdali

    2017-09-01

    Full Text Available In this paper we report upon the preparation and characterization of electrospun nanofibers of doped polyaniline (PANI/poly(methyl methacrylate (PMMA/amino-functionalized graphene (Am-rGO by electrospinning technique. The successful functionalization of rGO with amino groups is examined by Fourier transforms infrared (FTIR, X-ray photoelectron spectroscopy (XPS and Raman microspectrometer. The strong electric field enables the liquid jet to be ejected faster and also contributes to the improved thermal and morphological homogeneity of PANI/PMMA/Am-rGO. This results in a decrease in the average diameter of the produced fibers and shows that these fibers can find promising uses in many applications such as sensors, flexible electronics, etc.

  11. Chondroitin sulfate immobilization at the surface of electrospun nanofiber meshes for cartilage tissue regeneration approaches

    Energy Technology Data Exchange (ETDEWEB)

    Piai, Juliana Francis [3B’s Research Group − Biomaterials, Biodegradables and Biomimetics, Department of Polymer Engineering, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, 4805-017 Barco, Guimarães (Portugal); ICVS/3B’s − PT Government Associate Laboratory, Braga/Guimarães (Portugal); Grupo de Materiais Poliméricos e Compósitos, GMPC – Departamento de Química- Universidade Estadual de Maringá, Av. Colombo 5790, 87020-900, Maringá, Paraná (Brazil); Alves da Silva, Marta; Martins, Albino; Torres, Ana Bela [3B’s Research Group − Biomaterials, Biodegradables and Biomimetics, Department of Polymer Engineering, University of Minho, Headquarters of the European Institute of Excellence on Tissue Engineering and Regenerative Medicine, AvePark, 4805-017 Barco, Guimarães (Portugal); ICVS/3B’s − PT Government Associate Laboratory, Braga/Guimarães (Portugal); Faria, Susana [Research Center Officinal Mathematical, Department of Mathematics for Science and Technology, University of Minho, Campus de Azurém, 4800-058 Guimarães (Portugal); and others

    2017-05-01

    Highlights: • Chemical immobilization of chondroitin sulfate at the surface of nanofiber meshes. • CS-immobilized NFMs showed lower roughness and higher hydrophilicity. • CS-immobilized NFMs offer a highly effective substrate for hACs phenotypic stability. - Abstract: Aiming at improving the biocompatibility of biomaterial scaffolds, surface modification presents a way to preserve their mechanical properties and to improve the surface bioactivity. In this work, chondroitin sulfate (CS) was immobilized at the surface of electrospun poly(caprolactone) nanofiber meshes (PCL NFMs), previously functionalized by UV/O{sub 3} exposure and aminolysis. Contact angle, SEM, optical profilometry, FTIR, X-ray photoelectron spectroscopy techniques confirmed the success of CS-immobilization in PCL NFMs. Furthermore, CS-immobilized PCL NFMs showed lower roughness and higher hydrophilicity than the samples without CS. Human articular chondrocytes (hACs) were cultured on electrospun PCL NFMs with or without CS immobilization. It was observed that hACs proliferated through the entire time course of the experiment in both types of nanofibrous scaffolds, as well as for the production of glycosaminoglycans. Quantitative-PCR results demonstrated over-expression of cartilage-related genes such as Aggrecan, Collagen type II, COMP and Sox9 on both types of nanofibrous scaffolds. Morphological observations from SEM and LSCM revealed that hACs maintained their characteristic round shape and cellular agglomeration exclusively on PCL NFMs with CS immobilization. In conclusion, CS immobilization at the surface of PCL NFMs was achieved successfully and provides a valid platform enabling further surface functionalization methods in scaffolds to be developed for cartilage tissue engineering.

  12. Development and application of biomimetic electrospun nanofibers in total joint replacement

    Science.gov (United States)

    Song, Wei

    Failure of osseointegration (direct anchorage of an implant by bone formation at the bone-implant surface) and implant infection (such as that caused by Staphylococcus aureus, S. aureus) are the two main causes of implant failure and loosening. There is a critical need for orthopedic implants that promote rapid osseointegration and prevent bacterial colonization, particularly when placed in bone compromised by disease or physiology of the patients. A better understanding of the key factors that influence cell fate decisions at the bone-implant interface is required. Our study is to develop a class of "bone-like" nanofibers (NFs) that promote osseointegration while preventing bacterial colonization and subsequent infections. This research goal is supported by our preliminary data on the preparation of coaxial electrospun NFs composed of polycaprolactone (PCL) and polyvinyl alcohol (PVA) polymers arranged in a core-sheath shape. The PCL/PVA NFs are biocompatible and biodegradable with appropriate fiber diameter, pore size and mechanical strength, leading to enhanced cell adhesion, proliferation and differentiation of osteoblast precursor cells. The objective is to develop functionalized "bone-like" PCL/PVA NFs matrix embedded with antibiotics (doxycycline (Doxy), bactericidal and anti-osteoclastic) on prosthesis surface. Through a rat tibia implantation model, the Doxy incorporated coaxial NFs has demonstrated excellent in promoting osseointegration and bacteria inhibitory efficacy. NFs coatings significantly enhanced the bonding between implant and bone remodeling within 8 weeks. The SA-induced osteomyelitis was prevented by the sustained release of Doxy from NFs. The capability of embedding numerous bio-components including proteins, growth factors, drugs, etc. enables NFs an effective solution to overcome the current challenged issue in Total joint replacement. In summary, we proposed PCL/PVA electrospun nanofibers as promising biomaterials that can be applied on

  13. Atomic layer deposition of TiO2 on nitrogen-doped carbon nanofibers supported Ru nanoparticles for flexible Li-O2 battery: A combined DFT and experimental study

    Science.gov (United States)

    Yang, Jingbo; Mi, Hongwei; Luo, Shan; Li, Yongliang; Zhang, Peixin; Deng, Libo; Sun, Lingna; Ren, Xiangzhong

    2017-11-01

    Flexible Li-O2 batteries have attracted worldwide research interests and been considered to be potential alternatives for the next-generation flexible devices. Nitrogen-doped carbon nanofibers (N-CNFs) prepared by electrospinning are used as flexible substrate and an amorphous TiO2 layer is coated by atomic layer deposition (ALD) and then decorated with Ru nanoparticles. The Ru/N-CNFs@TiO2 composite is directly used as a free-standing electrode for Li-O2 batteries and the electrode delivers a high specific capacity, improved round-trip efficiency and good cycling ability. The superior electrochemical performance can be attributed to the amorphous TiO2 protecting layer and superior catalytic activity of Ru nanoparticles. Based on density functional theory (DFT) calculations from first principles, the carbon electrode after coating with TiO2 is more stable during discharge/charge process. The analysis of Li2O2 on three different interfaces (Li2O2/N-CNFs, Li2O2/TiO2, and Li2O2/Ru) indicates that the electron transport capacity was higher on Ru and TiO2 compared with N-CNFs, therefore, Li2O2 could be formed and decomposed more easily on the Ru/N-CNFs@TiO2 cathode. This work paves a way to develop the free-standing cathode materials for the future development of high-performance flexible energy storage systems.

  14. Fabrication and characterization of electrospun cellulose/nano-hydroxyapatite nanofibers for bone tissue engineering.

    Science.gov (United States)

    Ao, Chenghong; Niu, Yan; Zhang, Ximu; He, Xu; Zhang, Wei; Lu, Canhui

    2017-04-01

    Nanofibrous scaffolds from cotton cellulose and nano-hydroxyapatite (nano-HA) were electrospun for bone tissue engineering. The solution properties of cellulose/nano-HA spinning dopes and their associated electrospinnability were characterized. Morphological, thermal and mechanical properties of the electrospun cellulose/nano-HA nanocomposite nanofibers (ECHNN) were measured and the biocompatibility of ECHNN with human dental follicle cells (HDFCs) was evaluated. Scanning electron microscope (SEM) images indicated that the average diameter of ECHNN increased with a higher nano-HA loading and the fiber diameter distributions were well within the range of natural ECM (extra cellular matrix) fibers (50-500nm). The ECHNN exhibited extraordinary mechanical properties with a tensile strength and a Young's modulus up to 70.6MPa and 3.12GPa respectively. Moreover, it was discovered that the thermostability of the ECHNN could be enhanced with the incorporation of nano-HA. Cell culture experiments demonstrated that the ECHNN scaffolds were quite biocompatible for HDFCs attachment and proliferation, suggesting their great potentials as scaffold materials in bone tissue engineering. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Novel electrospun nanofibers of modified gelatin-tyrosine in cartilage tissue engineering.

    Science.gov (United States)

    Agheb, Maria; Dinari, Mohammad; Rafienia, Mohammad; Salehi, Hossein

    2017-02-01

    In natural cartilage tissues, chondrocytes are linked to extracellular matrix (ECM) through cell-surface binding proteins. Surface modification of gelatin can provide a new generation of biopolymers and fibrous scaffolds with chemical, mechanical, and biological properties. In this study tyrosine protein and 1,2,3-triazole ring were utilized to functionalize gelatin without Cu catalyst. Their molecular structure was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (1HNMR). Chemical cross-linkers such as glutaraldehyde (GA) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC)/N-hydroxysulfosuccinimide (NHS) were used to electrospin the modified gelatin. The modification of gelatin and cross-linking effects were confirmed by scanning electron microscopy (SEM), contact angle measurement, and mechanical tests. MTT assay using chondrocyte cells showed cell viability of electrospun modified gelatin scaffolds. In vitro cell culture studies showed that electrospun engineered protein scaffolds would support the attachment and growth of cells. The results also showed that cross-linked nanofibers with EDC/NHS could be considered excellent matrices in cell adhesion and proliferation before electrospinning process and their potential substrate in tissue engineering applications, especially in the field of cartilage engineering. Copyright © 2016. Published by Elsevier B.V.

  16. Chondroitin sulfate immobilization at the surface of electrospun nanofiber meshes for cartilage tissue regeneration approaches

    Science.gov (United States)

    Piai, Juliana Francis; da Silva, Marta Alves; Martins, Albino; Torres, Ana Bela; Faria, Susana; Reis, Rui L.; Muniz, Edvani Curti; Neves, Nuno M.

    2017-05-01

    Aiming at improving the biocompatibility of biomaterial scaffolds, surface modification presents a way to preserve their mechanical properties and to improve the surface bioactivity. In this work, chondroitin sulfate (CS) was immobilized at the surface of electrospun poly(caprolactone) nanofiber meshes (PCL NFMs), previously functionalized by UV/O3 exposure and aminolysis. Contact angle, SEM, optical profilometry, FTIR, X-ray photoelectron spectroscopy techniques confirmed the success of CS-immobilization in PCL NFMs. Furthermore, CS-immobilized PCL NFMs showed lower roughness and higher hydrophilicity than the samples without CS. Human articular chondrocytes (hACs) were cultured on electrospun PCL NFMs with or without CS immobilization. It was observed that hACs proliferated through the entire time course of the experiment in both types of nanofibrous scaffolds, as well as for the production of glycosaminoglycans. Quantitative-PCR results demonstrated over-expression of cartilage-related genes such as Aggrecan, Collagen type II, COMP and Sox9 on both types of nanofibrous scaffolds. Morphological observations from SEM and LSCM revealed that hACs maintained their characteristic round shape and cellular agglomeration exclusively on PCL NFMs with CS immobilization. In conclusion, CS immobilization at the surface of PCL NFMs was achieved successfully and provides a valid platform enabling further surface functionalization methods in scaffolds to be developed for cartilage tissue engineering.

  17. Biodegradable electrospun nanofibers coated with platelet-rich plasma for cell adhesion and proliferation

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Gomez, Luis [Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Instituto de Ortopedia y Banco de Tejidos Musculoesqueléticos, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Alvarez-Lorenzo, Carmen, E-mail: carmen.alvarez.lorenzo@usc.es [Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Concheiro, Angel [Departamento de Farmacia y Tecnología Farmacéutica, Facultad de Farmacia, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Silva, Maite [Instituto de Ortopedia y Banco de Tejidos Musculoesqueléticos, Universidad de Santiago de Compostela, 15872 Santiago de Compostela (Spain); Dominguez, Fernando [Fundación Publica Galega de Medicina Xenómica, Santiago de Compostela (Spain); Sheikh, Faheem A.; Cantu, Travis; Desai, Raj; Garcia, Vanessa L. [Department of Chemistry, University of Texas Pan American, Edinburg, TX 78541 (United States); Macossay, Javier, E-mail: jmacossay@utpa.edu [Department of Chemistry, University of Texas Pan American, Edinburg, TX 78541 (United States)

    2014-07-01

    Biodegradable electrospun poly(ε-caprolactone) (PCL) scaffolds were coated with platelet-rich plasma (PRP) to improve cell adhesion and proliferation. PRP was obtained from human buffy coat, and tested on human adipose-derived mesenchymal stem cells (MSCs) to confirm cell proliferation and cytocompatibility. Then, PRP was adsorbed on the PCL scaffolds via lyophilization, which resulted in a uniform sponge-like coating of 2.85 (S.D. 0.14) mg/mg. The scaffolds were evaluated regarding mechanical properties (Young's modulus, tensile stress and tensile strain), sustained release of total protein and growth factors (PDGF-BB, TGF-β1 and VEGF), and hemocompatibility. MSC seeded on the PRP–PCL nanofibers showed an increased adhesion and proliferation compared to pristine PCL fibers. Moreover, the adsorbed PRP enabled angiogenesis features observed as neovascularization in a chicken chorioallantoic membrane (CAM) model. Overall, these results suggest that PRP–PCL scaffolds hold promise for tissue regeneration applications. - Highlights: • Platelet-rich plasma (PRP) can be adsorbed on electrospun fibers via lyophilization. • PRP coating enhanced mesenchymal stem cell adhesion and proliferation on scaffolds. • PRP-coated scaffolds showed sustained release of growth factors. • Adsorbed PRP provided angiogenic features. • PRP-poly(ε-caprolactone) scaffolds hold promise for tissue regeneration applications.

  18. Preparation and Characterization of Vancomycin-Loaded Electrospun Rana chensinensis Skin Collagen/Poly(L-lactide Nanofibers for Drug Delivery

    Directory of Open Access Journals (Sweden)

    Mei Zhang

    2016-01-01

    Full Text Available Collagen was extracted from abandoned Rana chensinensis skin in northeastern China via an acid enzymatic extraction method for the use of drug carriers. In this paper we demonstrated two different nanofiber-vancomycin (VCM systems, that is, VCM blended nanofibers and core-shell nanofibers with VCM in the core. Rana chensinensis skin collagen (RCSC and poly(L-lactide (PLLA (3 : 7 were blended in 1,1,1,3,3,3-hexafluoroisopropanol (HFIP at a concentration of 10% (g/mL to fabricate coaxial and blend nanofibers, respectively. Coaxial and blend electrospun RCSC/PLLA nanofibers containing VCM (5 wt% were evaluated for the local and temporal delivery of VCM. The nanofiber scaffolds were characterized by environmental scanning electron microscope (ESEM, transmission electron microscopy (TEM, Fourier transform infrared spectra (FTIR, differential scanning calorimeter (DSC, water contact angle (WCA, and mechanical tests. The drug release of VCM in these two systems was compared by using UV spectrophotometer. The empirical result indicated that both the blend and coaxial RCSC/PLLA scaffolds followed sustained control release for a period of 80 hours, but the coaxial nanofiber might be a potential drug delivery material for its better mechanical properties and sustained release effect.

  19. Nanofiber Alignment Regulates NIH3T3 Cell Orientation and Cytoskeletal Gene Expression on Electrospun PCL+Gelatin Nanofibers.

    Science.gov (United States)

    Fee, Timothy; Surianarayanan, Swetha; Downs, Crawford; Zhou, Yong; Berry, Joel

    2016-01-01

    To examine the influence of substrate topology on the behavior of fibroblasts, tissue engineering scaffolds were electrospun from polycaprolactone (PCL) and a blend of PCL and gelatin (PCL+Gel) to produce matrices with both random and aligned nanofibrous orientations. The addition of gelatin to the scaffold was shown to increase the hydrophilicity of the PCL matrix and to increase the proliferation of NIH3T3 cells compared to scaffolds of PCL alone. The orientation of nanofibers within the matrix did not have an effect on the proliferation of adherent cells, but cells on aligned substrates were shown to elongate and align parallel to the direction of substrate fiber alignment. A microarray of cyotoskeleton regulators was probed to examine differences in gene expression between cells grown on an aligned and randomly oriented substrates. It was found that transcriptional expression of eight genes was statistically different between the two conditions, with all of them being upregulated in the aligned condition. The proteins encoded by these genes are linked to production and polymerization of actin microfilaments, as well as focal adhesion assembly. Taken together, the data indicates NIH3T3 fibroblasts on aligned substrates align themselves parallel with their substrate and increase production of actin and focal adhesion related genes.

  20. Comparative performance of electrospun collagen nanofibers cross-linked by means of different methods.

    Science.gov (United States)

    Torres-Giner, Sergio; Gimeno-Alcañiz, Jose V; Ocio, Maria J; Lagaron, Jose M

    2009-01-01

    Collagen, as the major structural protein of the extracellular matrix in animals, is a versatile biomaterial of great interest in various engineering applications. Electrospun nanofibers of collagen are regarded as very promising materials for tissue engineering applications because they can reproduce the morphology of the natural bone but have as a drawback a poor structural consistency in wet conditions. In this paper, a comparative study between the performance of different cross-linking methods such as a milder enzymatic treatment procedure using transglutaminase, the use of N-[3-(dimethylamino)propyl]-N'-ethylcarbodiimide hydrochloride/N-hydroxysuccinimide, and genipin, and the use of a physical method based on exposure to ultraviolet light was carried out. The chemical and enzymatic treatments provided, in this order, excellent consistency, morphology, cross-linking degree, and osteoblast viability for the collagen nanofibers. Interestingly, the enzymatically cross-linked collagen mats, which are considered to be a more biological treatment, promoted adequate cell adhesion, making the biomaterial biocompatible and with an adequate degree of porosity for cell seeding and in-growth.

  1. Electrospun polymethylacrylate nanofibers membranes for quasi-solid-state dye sensitized solar cells

    Directory of Open Access Journals (Sweden)

    M. Fathy

    2016-06-01

    Full Text Available Polymethylacrylate (PMA nanofibers membranes are fabricated by electrospinning technique and applied to the polymer matrix in quasi-solid-state electrolytes for dye sensitized solar cells (DSSCs. There is no previous studies reporting the production of PMA nanofibers. The electrospinning parameters such as polymer concentration, applied voltage, feed rate, tip to collector distance and solvent were optimized. Electrospun PMA fibrous membrane with average fiber diameter of 350 nm was prepared from a 10 wt% solution of PMA in a mixture of acetone/N,N-dimethylacetamide (6:4 v/v at an applied voltage of 20 kV. It was then activated by immersing it in 0.5 M LiI, 0.05 M I2, and 0.5 M 4-tert-butylpyridine in 3-methoxyproponitrile to obtain the corresponding membrane electrolyte with an ionic conductivity of 2.4 × 10−3 S cm−1 at 25 °C. Dye sensitized solar cells (DSSCs employing the quasi solid-state electrolyte have an open-circuit voltage (Voc of 0.65 V and a short circuit current (Jsc of 6.5 mA cm−2 and photoelectric energy conversion efficiency (η of 1.4% at an incident light intensity of 100 mW cm−2.

  2. Embedded Ceria Nanoparticles in Crosslinked PVA Electrospun Nanofibers as Optical Sensors for Radicals

    Directory of Open Access Journals (Sweden)

    Nader Shehata

    2016-08-01

    Full Text Available This work presents a new nanocomposite of cerium oxide (ceria nanoparticles embedded in electrospun PVA nanofibers for optical sensing of radicals in solutions. Our ceria nanoparticles are synthesized to have O-vacancies which are the receptors for the radicals extracted from peroxide in water solution. Ceria nanoparticles are embedded insitu in PVA solution and then formed as nanofibers using an electrospinning technique. The formed nanocomposite emits visible fluorescent emissions under 430 nm excitation, due to the active ceria nanoparticles with fluorescent Ce3+ ionization states. When the formed nanocomposite is in contact with peroxide solution, the fluorescence emission intensity peak has been found to be reduced with increasing concentration of peroxide or the corresponding radicals through a fluorescence quenching mechanism. The fluorescence intensity peak is found to be reduced to more than 30% of its original value at a peroxide weight concentration up to 27%. This work could be helpful in further applications of radicals sensing using a solid mat through biomedical and environmental monitoring applications.

  3. Fluorescent Nanocomposite of Embedded Ceria Nanoparticles in Crosslinked PVA Electrospun Nanofibers

    Directory of Open Access Journals (Sweden)

    Nader Shehata

    2016-06-01

    Full Text Available This paper introduces a new fluorescent nanocomposite of electrospun biodegradable nanofibers embedded with optical nanoparticles. In detail, this work introduces the fluorescence properties of PVA nanofibers generated by the electrospinning technique with embedded cerium oxide (ceria nanoparticles. Under near-ultra violet excitation, the synthesized nanocomposite generates a visible fluorescent emission at 520 nm, varying its intensity peak according to the concentration of in situ embedded ceria nanoparticles. This is due to the fact that the embedded ceria nanoparticles have optical tri-valiant cerium ions, associated with formed oxygen vacancies, with a direct allowed bandgap around 3.5 eV. In addition, the impact of chemical crosslinking of the PVA on the fluorescence emission is studied in both cases of adding ceria nanoparticles in situ or of a post-synthesis addition via a spin-coating mechanism. Other optical and structural characteristics such as absorbance dispersion, direct bandgap, FTIR spectroscopy, and SEM analysis are presented. The synthesized optical nanocomposite could be helpful in different applications such as environmental monitoring and bioimaging.

  4. Electrospun sulfonated poly(ether ketone) nanofibers as proton conductive reinforcement for durable Nafion composite membranes

    Science.gov (United States)

    Klose, Carolin; Breitwieser, Matthias; Vierrath, Severin; Klingele, Matthias; Cho, Hyeongrae; Büchler, Andreas; Kerres, Jochen; Thiele, Simon

    2017-09-01

    We show that the combination of direct membrane deposition with proton conductive nanofiber reinforcement yields highly durable and high power density fuel cells. Sulfonated poly(ether ketone) (SPEK) was directly electrospun onto gas diffusion electrodes and then filled with Nafion by inkjet-printing resulting in a 12 μm thin membrane. The ionic membrane resistance (30 mΩ*cm2) was well below that of a directly deposited membrane reinforced with chemically inert (PVDF-HFP) nanofibers (47 mΩ*cm2) of comparable thickness. The power density of the fuel cell with SPEK reinforced membrane (2.04 W/cm2) is 30% higher than that of the PVDF-HFP reinforced reference sample (1.57 W/cm2). During humidity cycling and open circuit voltage (OCV) hold, the SPEK reinforced Nafion membrane showed no measurable degradation in terms of H2 crossover current density, thus fulfilling the target of 2 mA/cm2 of the DOE after degradation. The chemical accelerated stress test (100 h OCV hold at 90 °C, 30% RH, H2/air, 50/50 kPa) revealed a degradation rate of about 0.8 mV/h for the fuel cell with SPEK reinforced membrane, compared to 1.0 mV/h for the PVDF-HFP reinforced membrane.

  5. A facile route for controlled alignment of carbon nanotube-reinforced, electrospun nanofibers using slotted collector plates

    Directory of Open Access Journals (Sweden)

    G. R. Rakesh

    2015-02-01

    Full Text Available A facile route for controlled alignment of electrospun multiwalled carbon nanotube (MWCNT-reinforced Polyvinyl Alcohol (PVA nanofibers using slotted collector geometries has been realized. The process is based on analytical predictions using electrostatic field analysis for envisaging the extent of alignment of the electrospun fibers on varied collector geometries. Both the experimental and theoretical studies clearly indicate that the introduction of an insulating region into a conductive collector significantly influences the electrostatic forces acting on a charged fiber. Among various collector geometries, rectangular slotted collectors with circular ends showed good fiber alignment over a large collecting area. The electrospun fibers produced by this process were characterized by Atomic Force Microscopy (AFM, High Resolution Transmission Electron Microscopy (HRTEM, Scanning Electron Microscopy (SEM and Optical Microscopy. Effects of electrospinning time and slot widths on the fiber alignment have been analyzed. PVA-MWCNT nanofibers were found to be conducting in nature owing to the presence of reinforced MWCNTs in PVA matrix. The method can enable the direct integration of aligned nanofibers with controllable configurations, and significantly simplify the production of nanofibersbased devices.

  6. Electrospun micro- and nanofiber tubes for functional nervous regeneration in sciatic nerve transections

    Directory of Open Access Journals (Sweden)

    Amadio Stefano

    2008-04-01

    Full Text Available Abstract Background Although many nerve prostheses have been proposed in recent years, in the case of consistent loss of nervous tissue peripheral nerve injury is still a traumatic pathology that may impair patient's movements by interrupting his motor-sensory pathways. In the last few decades tissue engineering has opened the door to new approaches;: however most of them make use of rigid channel guides that may cause cell loss due to the lack of physiological local stresses exerted over the nervous tissue during patient's movement. Electrospinning technique makes it possible to spin microfiber and nanofiber flexible tubular scaffolds composed of a number of natural and synthetic components, showing high porosity and remarkable surface/volume ratio. Results In this study we used electrospun tubes made of biodegradable polymers (a blend of PLGA/PCL to regenerate a 10-mm nerve gap in a rat sciatic nerve in vivo. Experimental groups comprise lesioned animals (control group and lesioned animals subjected to guide conduits implantated at the severed nerve stumps, where the tubular scaffolds are filled with saline solution. Four months after surgery, sciatic nerves failed to reconnect the two stumps of transected nerves in the control animal group. In most of the treated animals the electrospun tubes induced nervous regeneration and functional reconnection of the two severed sciatic nerve tracts. Myelination and collagen IV deposition have been detected in concurrence with regenerated fibers. No significant inflammatory response has been found. Neural tracers revealed the re-establishment of functional neuronal connections and evoked potential results showed the reinnervation of the target muscles in the majority of the treated animals. Conclusion Corroborating previous works, this study indicates that electrospun tubes, with no additional biological coating or drug loading treatment, are promising scaffolds for functional nervous regeneration. They

  7. Determining the mechanical properties of electrospun poly-ε-caprolactone (PCL) nanofibers using AFM and a novel fiber anchoring technique

    Energy Technology Data Exchange (ETDEWEB)

    Baker, Stephen R.; Banerjee, Soham; Bonin, Keith; Guthold, Martin, E-mail: gutholdm@wfu.edu

    2016-02-01

    Due to its low cost, biocompatibility and slow bioresorption, poly-ε-caprolactone (PCL) continues to be a suitable material for select biomedical engineering applications. We used a combined atomic force microscopy (AFM)/optical microscopy technique to determine key mechanical properties of individual electrospun PCL nanofibers with diameters between 440–1040 nm. Compared to protein nanofibers, PCL nanofibers showed much lower adhesion, as they slipped on the substrate when mechanically manipulated. We, therefore, first developed a novel technique to anchor individual PCL nanofibers to micrometer-sized ridges on a substrate, and then mechanically tested anchored nanofibers. When held at constant strain, tensile stress relaxed with fast and slow relaxation times of 1.0 ± 0.3 s and 8.8 ± 3.1 s, respectively. The total tensile modulus was 62 ± 26 MPa, the elastic (non-relaxing) component of the tensile modulus was 53 ± 36 MPa. Individual PCL fibers could be stretched elastically (without permanent deformation) to strains of 19–23%. PCL nanofibers are rather extensible; they could be stretched to a strain of at least 98%, and a tensile strength of at least 12 MPa, before they slipped off the AFM tip. PCL nanofibers that had aged for over a month at ambient conditions became stiffer and less elastic. Our technique provides accurate nanofiber mechanical data, which are needed to guide construction of scaffolds for cells and other biomedical devices. - Highlights: • Developed technique to anchor single nanofibers on microridges • Determined mechanical properties of e-spun PCL fibers • E-spun PCL fibers have similar mechanical properties as wet fibrin fibers. • E-spun PCL fiber total elastic modulus is ~ 60 MPa. • E-spun PCL fiber extensibility is > 100%.

  8. Fabrication of mineralized electrospun PLGA and PLGA/gelatin nanofibers and their potential in bone tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Z.X. [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Li, H.F. [Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871 (China); Sun, Z.Z. [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Zheng, W., E-mail: zhengwei@hrbeu.edu.cn [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Zheng, Y.F., E-mail: yfzheng@pku.edu.cn [Center for Biomedical Materials and Engineering, Harbin Engineering University, Harbin 150001 (China); Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871 (China)

    2013-03-01

    Surface mineralization is an effective method to produce calcium phosphate apatite coating on the surface of bone tissue scaffold which could create an osteophilic environment similar to the natural extracellular matrix for bone cells. In this study, we prepared mineralized poly(D,L-lactide-co-glycolide) (PLGA) and PLGA/gelatin electrospun nanofibers via depositing calcium phosphate apatite coating on the surface of these nanofibers to fabricate bone tissue engineering scaffolds by concentrated simulated body fluid method, supersaturated calcification solution method and alternate soaking method. The apatite products were characterized by the scanning electron microscopy (SEM), Fourier transform-infrared spectroscopy (FT-IR), and X-ray diffractometry (XRD) methods. A large amount of calcium phosphate apatite composed of dicalcium phosphate dihydrate (DCPD), hydroxyapatite (HA) and octacalcium phosphate (OCP) was deposited on the surface of resulting nanofibers in short times via three mineralizing methods. A larger amount of calcium phosphate was deposited on the surface of PLGA/gelatin nanofibers rather than PLGA nanofibers because gelatin acted as nucleation center for the formation of calcium phosphate. The cell culture experiments revealed that the difference of morphology and components of calcium phosphate apatite did not show much influence on the cell adhesion, proliferation and activity. - Highlights: Black-Right-Pointing-Pointer Ca-P phases were coated on PLGA/gelatin electrospun nanofiber membranes within 3 h. Black-Right-Pointing-Pointer Ca-P coatings prepared by 3 methods exhibited different structures and components. Black-Right-Pointing-Pointer The Ca-P coating weight increase depends on the apatite nucleation velocity. Black-Right-Pointing-Pointer Surface hydrophilicity enhanced the velocity and quantity of apatite nucleation. Black-Right-Pointing-Pointer The resulting Ca-P apatite coatings exhibit good biocompatibility to MG63 cells.

  9. Electrospun PLLA nanofiber scaffolds and their use in combination with BMP-2 for reconstruction of bone defects.

    Directory of Open Access Journals (Sweden)

    Markus D Schofer

    Full Text Available Adequate migration and differentiation of mesenchymal stem cells is essential for regeneration of large bone defects. To achieve this, modern graft materials are becoming increasingly important. Among them, electrospun nanofiber scaffolds are a promising approach, because of their high physical porosity and potential to mimic the extracellular matrix (ECM.The objective of the present study was to examine the impact of electrospun PLLA nanofiber scaffolds on bone formation in vivo, using a critical size rat calvarial defect model. In addition we analyzed whether direct incorporation of bone morphogenetic protein 2 (BMP-2 into nanofibers could enhance the osteoinductivity of the scaffolds. Two critical size calvarial defects (5 mm were created in the parietal bones of adult male Sprague-Dawley rats. Defects were either (1 left unfilled, or treated with (2 bovine spongiosa, (3 PLLA scaffolds alone or (4 PLLA/BMP-2 scaffolds. Cranial CT-scans were taken at fixed intervals in vivo. Specimens obtained after euthanasia were processed for histology, histomorphometry and immunostaining (Osteocalcin, BMP-2 and Smad5.PLLA scaffolds were well colonized with cells after implantation, but only showed marginal ossification. PLLA/BMP-2 scaffolds showed much better bone regeneration and several ossification foci were observed throughout the defect. PLLA/BMP-2 scaffolds also stimulated significantly faster bone regeneration during the first eight weeks compared to bovine spongiosa. However, no significant differences between these two scaffolds could be observed after twelve weeks. Expression of osteogenic marker proteins in PLLA/BMP-2 scaffolds continuously increased throughout the observation period. After twelve weeks osteocalcin, BMP-2 and Smad5 were all significantly higher in the PLLA/BMP-2 group than in all other groups.Electrospun PLLA nanofibers facilitate colonization of bone defects, while their use in combination with BMP-2 also increases bone

  10. Functionalized chitosan electrospun nanofiber for effective removal of trace arsenate from water

    Science.gov (United States)

    Min, Ling-Li; Zhong, Lu-Bin; Zheng, Yu-Ming; Liu, Qing; Yuan, Zhi-Huan; Yang, Li-Ming

    2016-08-01

    An environment-friendly iron functionalized chitosan elctrospun nanofiber (ICS-ENF) was synthesized for trace arsenate removal from water. The ICS-ENF was fabricated by electrospinning a mixture of chitosan, PEO and Fe3+ followed by crosslinking with ammonia vapor. The physicochemical properties of ICS-ENF were characterized by FESEM, TEM-EDX and XRD. The ICS-ENF was found to be highly effective for As(V) adsorption at neutral pH. The As(V) adsorption occurred rapidly and achieved equilibrium within 100 min, which was well fitted by pseudo-second-order kinetics model. The As(V) adsorption decreased with increased ionic strength, suggesting an outer-sphere complexation of As(V) on ICS-ENF. Freundlich model well described the adsorption isotherm, and the maximum adsorption capacity was up to 11.2 mg/g at pH 7.2. Coexisting anions of chloride and sulfate showed negligible influence on As(V) removal, but phosphate and silicate significantly reduced As(V) adsorption by competing for adsorption sites. FTIR and XPS analysis demonstrated -NH, -OH and C-O were responsible for As(V) uptake. ICS-ENF was easily regenerated using 0.003 M NaOH, and the removal rate remained above 98% after ten successively adsorption-desorption recycles. This study extends the potential applicability of electrospun nanofibers for water purification and provides a promising approach for As(V) removal from water.

  11. In situ Polymerization of Multi-Walled Carbon Nanotube/Nylon-6 Nanocomposites and Their Electrospun Nanofibers

    Science.gov (United States)

    Saeed, Khalid; Park, Soo-Young; Haider, Sajjad; Baek, Jong-Beom

    2009-01-01

    Multiwalled carbon nanotube/nylon-6 nanocomposites (MWNT/nylon-6) were prepared by in situ polymerization, whereby functionalized MWNTs (F-MWNTs) and pristine MWNTs (P-MWNTs) were used as reinforcing materials. The F-MWNTs were functionalized by Friedel-Crafts acylation, which introduced aromatic amine (COC6H4-NH2) groups onto the side wall. Scanning electron microscopy (SEM) images obtained from the fractured surfaces of the nanocomposites showed that the F-MWNTs in the nylon-6 matrix were well dispersed as compared to those of the P-MWNTs. Both nanocomposites could be electrospun into nanofibers in which the MWNTs were embedded and oriented along the nanofiber axis, as confirmed by transmission electron microscopy. The specific strength and modulus of the MWNTs-reinforced nanofibers increased as compared to those of the neat nylon-6 nanofibers. The crystal structure of the nylon-6 in the MWNT/nylon-6 nanofibers was mostly γ-phase, although that of the MWNT/nylon-6 films, which were prepared by hot-pressing the pellets between two aluminum plates and then quenching them in icy water, was mostly α-phase, indicating that the shear force during electrospinning might favor the γ-phase, similarly to the conventional fiber spinning.

  12. Three-dimensional network films of electrospun copper oxide nanofibers for glucose determination.

    Science.gov (United States)

    Wang, Wen; Zhang, Lili; Tong, Shengfu; Li, Xin; Song, Wenbo

    2009-12-15

    Copper oxide nanofibers (CuO-NFs) prepared by electrospinning and subsequent thermal treatment processes were demonstrated for the first time for glucose non-enzymatic determination. The structures and morphologies of CuO-NFs were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X-ray diffraction spectrum (XRD). Different dispersants were utilized for the suspension preparation and effects of ultrasonic time on the films electrode fabrication were investigated in detail. The assay performances to glucose were evaluated by cyclic voltammetry (CV) and chronoamperometry (I-t). Results revealed a high sensitivity (431.3 microAmM(-1)cm(-2)), fast response (about 1s), long-term stability and excellent resistance towards electrode fouling in the glucose determination at +0.40V. The improved performances of CuO-NFs films electrode for electro-oxidation glucose were ascribed to the high surface-to-volume ratio, complex pore structure, extremely long length of the as-prepared CuO-NFs, and the excellent three-dimensional network structure after immobilization. Results in this study suggest that electrospun CuO-NFs is a promising 1-D nanomaterial for further design and microfabrication of bioelectrochemical nanodevices for glucose determination.

  13. Energy harvesting from electrospun piezoelectric nanofibers for structural health monitoring of a cable-stayed bridge

    Science.gov (United States)

    Maruccio, Claudio; Quaranta, Giuseppe; De Lorenzis, Laura; Monti, Giorgio

    2016-08-01

    Wireless monitoring could greatly impact the fields of structural health assessment and infrastructure asset management. A common problem to be tackled in wireless networks is the electric power supply, which is typically provided by batteries replaced periodically. A promising remedy for this issue would be to harvest ambient energy. Within this framework, the present paper proposes to harvest ambient-induced vibrations of bridge structures using a new class of piezoelectric textiles. The considered case study is an existing cable-stayed bridge located in Italy along a high-speed road that connects Rome and Naples, for which a recent monitoring campaign has allowed to record the dynamic responses of deck and cables. Vibration measurements have been first elaborated to provide a comprehensive dynamic assessment of this infrastructure. In order to enhance the electric energy that can be converted from ambient vibrations, the considered energy harvester exploits a power generator built using arrays of electrospun piezoelectric nanofibers. A finite element analysis is performed to demonstrate that such power generator is able to provide higher energy levels from recorded dynamic loading time histories than a standard piezoelectric energy harvester. Its feasibility for bridge health monitoring applications is finally discussed.

  14. Enhanced piezoresponse of highly aligned electrospun poly(vinylidene fluoride) nanofibers

    Science.gov (United States)

    Kang, Sung Bum; Won, Sang Hyuk; Im, Min Ji; Kim, Chan Ul; Park, Won Il; Baik, Jeong Min; Choi, Kyoung Jin

    2017-09-01

    Well-ordered nanostructure arrays with controlled densities can potentially improve material properties; however, their fabrication typically involves the use of complicated processing techniques. In this work, we demonstrate a uniaxial alignment procedure for fabricating poly(vinylidene fluoride) (PVDF) electrospun nanofibers (NFs) by introducing collectors with additional steps. The mechanism of the observed NF alignment, which occurs due to the concentration of lateral electric field lines around collector steps, has been elucidated via finite-difference time-domain simulations. The membranes composed of well-aligned PVDF NFs are characterized by a higher content of the PVDF β-phase, as compared to those manufactured from randomly orientated fibers. The piezoelectric energy harvester, which was fabricated by transferring well-aligned PVDF NFs onto flexible substrates with Ag electrodes attached to both sides, exhibited a 2-fold increase in the output voltage and a 3-fold increase in the output current as compared to the corresponding values obtained for the device manufactured from randomly oriented NFs. The enhanced piezoresponse observed for the aligned PVDF NFs is due to their higher β-phase content, denser structure, smaller effective radius of curvature during bending, greater applied strain, and higher fraction of contributing NFs.

  15. Preparation and Evaluation of Dexamethasone-Loaded Electrospun Nanofiber Sheets as a Sustained Drug Delivery System

    Directory of Open Access Journals (Sweden)

    Jin Woo Lee

    2016-03-01

    Full Text Available Recently, electrospinning technology has been widely used as a processing method to make nanofiber sheets (NS for biomedical applications because of its unique features, such as ease of fabrication and high surface area. To develop a sustained dexamethasone (Dex delivery system, in this work, poly(ε-caprolactone-co-l-lactide (PCLA copolymer with controllable biodegradability was synthesized and further utilized to prepare electrospun Dex-loaded NS using water-insoluble Dex (Dex(b or water-soluble Dex (Dex(s. The Dex-NS obtained by electrospinning exhibited randomly oriented and interconnected fibrillar structures. The in vitro and in vivo degradation of Dex-NS was confirmed over a period of a few weeks by gel permeation chromatography (GPC and nuclear magnetic resonance (NMR. The evaluation of in vitro and in vivo Dex(b and Dex(s release from Dex-NS showed an initial burst of Dex(b at day 1 and, thereafter, almost the same amount of release as Dex(b for up to 28 days. In contrast, Dex(s-NS exhibited a small initial burst of Dex(s and a first-order releasing profile from Dex-NS. In conclusion, Dex-NS exhibited sustained in vitro and in vivo Dex(s release for a prolonged period, as well as controlled biodegradation of the NS over a defined treatment period.

  16. Triaxial electrospun nanofiber membranes for controlled dual release of functional molecules.

    Science.gov (United States)

    Han, Daewoo; Steckl, Andrew J

    2013-08-28

    A novel dual drug delivery system is presented using triaxial structured nanofibers, which provides different release profiles for model drugs separately loaded in either the sheath or the core of the fiber. Homogenous, coaxial and triaxial fibers containing a combination of materials (PCL, polycaprolactone; PVP, polyvinylpyrrolidone) were fabricated. The drug release profiles were simulated using two color dyes (KAB, keyacid blue; KAU, keyacid uranine), whose release in physiological solution was measured using optical absorption as a function of time. To reach the level of 80% release of encapsulated dye from core, triaxial fibers with a PCL intermediate layer exhibited a ~24× slower release than that from coaxial fibers. At the same time, the hygroscopic sheath layer of the triaxial fibers provided an initial burst release (~ 80% within an hour) of a second dye as high as that from conventional single and coaxial fibers. The triaxial fiber membrane provides both a quick release from the outer sheath layer for short-term treatment and a sustained release from the fiber core for long-term treatment. The intermediate layer between inner core and outer sheath acts as a barrier to prevent leaching from the core, which can be especially important when the membranes are used in wet application. The formation of tri/multiaxially electrospun nanofibrous membranes will be greatly beneficial for biomedical applications by enabling different release profiles of two different drugs from a membrane.

  17. Use of Polycaprolactone Electrospun Nanofibers as a Coating for Poly(methyl methacrylate) Bone Cement.

    Science.gov (United States)

    Khandaker, Morshed; Riahinezhad, Shahram; Jamadagni, Harsha G; Morris, Tracy L; Coles, Alexis V; Vaughan, Melville B

    2017-07-10

    Poly(methyl methacrylate) (PMMA) bone cement has limited biocompatibility. Polycaprolactone (PCL) electrospun nanofiber (ENF) has many applications in the biomedical field due to its excellent biocompatibility and degradability. The effect of coating PCL ENF on the surface topography, biocompatibility, and mechanical strength of PMMA bone cement is not currently known. This study is based on the hypothesis that the PCL ENF coating on PMMA will increase PMMA roughness leading to increased biocompatibility without influencing its mechanical properties. This study prepared PMMA samples without and with the PCL ENF coating, which were named the control and ENF coated samples. This study determined the effects on the surface topography and cytocompatibility (osteoblast cell adhesion, proliferation, mineralization, and protein adsorption) properties of each group of PMMA samples. This study also determined the bending properties (strength, modulus, and maximum deflection at fracture) of each group of PMMA samples from an American Society of Testing Metal (ASTM) standard three-point bend test. This study found that the ENF coating on PMMA significantly improved the surface roughness and cytocompatibility properties of PMMA (p 0.05). Therefore, the PCL ENF coating technique should be further investigated for its potential in clinical applications.

  18. Preparation, characterization, and in vitro diffusion study of nonwoven electrospun nanofiber of curcumin-loaded cellulose acetate phthalate polymer

    Directory of Open Access Journals (Sweden)

    Rramaswamy Ravikumar

    2017-09-01

    Full Text Available Novel curcumin (CUR-loaded cellulose acetate phthalate (CAP nonwoven electrospun nanofiber (NF transdermal mat was developed and evaluated for its in vitro CUR diffusion properties. Various CAP solutions from 5 to 20 wt% were tested; 17.5 wt% was found to be a suitable concentration for NF fabrication without defects, such as bubble or ribbon structures. The selected wt% CAP solution was loaded with CUR and electrospun into NFs. The prepared CUR-loaded NFs were characterized using scanning electron microscopy, X-ray diffraction, ultraviolet–visible spectroscopy, thermogravimetric analysis (TGA, and in vitro diffusion studies. The as-prepared fibers demonstrated controlled in vitro transdermal delivery of CUR for up to 24 h.

  19. Preparation, characterization, andin vitrodiffusion study of nonwoven electrospun nanofiber of curcumin-loaded cellulose acetate phthalate polymer.

    Science.gov (United States)

    Ravikumar, Rramaswamy; Ganesh, Mani; Ubaidulla, Udumansha; Young Choi, Eun; Tae Jang, Hyun

    2017-09-01

    Novel curcumin (CUR)-loaded cellulose acetate phthalate (CAP) nonwoven electrospun nanofiber (NF) transdermal mat was developed and evaluated for its in vitro CUR diffusion properties. Various CAP solutions from 5 to 20 wt% were tested; 17.5 wt% was found to be a suitable concentration for NF fabrication without defects, such as bubble or ribbon structures. The selected wt% CAP solution was loaded with CUR and electrospun into NFs. The prepared CUR-loaded NFs were characterized using scanning electron microscopy, X-ray diffraction, ultraviolet-visible spectroscopy, thermogravimetric analysis (TGA), and in vitro diffusion studies. The as-prepared fibers demonstrated controlled in vitro transdermal delivery of CUR for up to 24 h.

  20. Highly efficient hybrid energy generator: coupled organic photovoltaic device and randomly oriented electrospun poly(vinylidene fluoride) nanofiber.

    Science.gov (United States)

    Park, Boongik; Lee, Kihwan; Park, Jongjin; Kim, Jongmin; Kim, Ohyun

    2013-03-01

    A hybrid architecture consisting of an inverted organic photovoltaic device and a randomly-oriented electrospun PVDF piezoelectric device was fabricated as a highly-efficient energy generator. It uses the inverted photovoltaic device with coupled electrospun PVDF nanofibers as tandem structure to convert solar and mechanical vibrations energy to electricity simultaneously or individually. The power conversion efficiency of the photovoltaic device was also significantly improved up to 4.72% by optimized processes such as intrinsic ZnO, MoO3 and active layer. A simple electrospinning method with the two electrode technique was adopted to achieve a high voltage of - 300 mV in PVDF piezoelectric fibers. Highly-efficient HEG using voltage adder circuit provides the conceptual possibility of realizing multi-functional energy generator whenever and wherever various energy sources are available.

  1. Influence of layer-by-layer assembled electrospun poly (L-lactic acid) nanofiber mats on the bioactivity of endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Keke; Zhang, Xiazhi; Yang, Wufeng; Liu, Xiaoyan; Jiao, Yanpeng, E-mail: tjiaoyp@jnu.edu.cn; Zhou, Changren

    2016-12-30

    Highlights: • Layer-by-layer assembled PLLA nanofiber mats were successfully prepared. • The modified PLLA nanofiber mats enhanced the adhesion, proliferation of endothelial cells. • The modified PLLA nanofiber mats had inhibited the inflammatory response to some extent. - Abstract: Electrospun poly(L-lactic acid) (PLLA) nanofiber mats were successfully modified by deposition of multilayers with chitosan (CS), heparin (Hep) and graphene oxide (GO) through electrostatic layer-by-layer (LBL) self-assembly method. In this study, the surface properties of PLLA nanofiber mats before and after modification were investigated via scanning electron microscope (SEM), atomic force microscopy (AFM), attenuated total reflectance fourier transformation infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and water contact angle measurement. In addition, the cytocompatibility of the modified PLLA nanofiber mats were investigated by testing endothelial cells compatibility, including cell attachment, cell proliferation and cell cycle. The results revealed that the surfaces of modified PLLA nanofiber mats become much rougher, stifiness and the hydrophilicity of the LBL modified PLLA nanofiber mats were improved compared to original PLLA one. Moreover, the modified PLLA nanofiber mats had promoted the endothelial cells viability attachment significantly. Besides, we studied the PLLA nanofiber mats on the expression of necrosis factor (TNF-α), interleukine-1β (IL-1β), monocyte chemoattractant protein-1 (MCP-1) and vascular cell adhesion molecule-1 (VCAM-1) in endothelial cells. The results showed that modified PLLA nanofiber mats had inhibited the inflammatory response to some extent.

  2. Improved conversion efficiency in dye-sensitized solar cells based on electrospun Al-doped ZnO nanofiber electrodes prepared by seed layer treatment

    Science.gov (United States)

    Yun, Sining; Lim, Sangwoo

    2011-02-01

    The application of electrospun nanofibers in electronic devices is limited due to their poor adhesion to conductive substrates. To improve this, a seed layer (SD) is introduced on the FTO substrate before the deposition of the electrospun composite nanofibers. This facilitates the release of interfacial tensile stress during calcination and enhances the interfacial adhesion of the AZO nanofiber films with the FTO substrate. Dye-sensitized solar cells (DSSC) based on these AZO nanofiber photoelectrodes have been fabricated and investigated. An energy conversion efficiency ( η) of 0.54-0.55% has been obtained under irradiation of AM 1.5 simulated sunlight (100 mW/cm 2), indicating a massive improvement of η in the AZO nanofiber film DSSCs after SD-treatment of the FTO substrate as compared to those with no treatment. The SD-treatment has been demonstrated to be a simple and facile method to solve the problem of poor adhesion between electrospun nanofibers and the conductive substrate.

  3. Electrochemical performance of fulvic acid-based electrospun hard carbon nanofibers as promising anodes for sodium-ion batteries

    Science.gov (United States)

    Zhao, Pin-Yi; Zhang, Jie; Li, Qi; Wang, Cheng-Yang

    2016-12-01

    The electrochemical performance of fulvic acid-based electrospun hard carbon nanofibers (PF-CNFs) as anodes for sodium-ion batteries is reported. PF-CNFs were prepared, stabilization in air at 280 °C and then carbonized in N2 at 800, 1000, 1300 or 1500 °C. The PF-CNFs prepared at 1300 °C had abundant oxygen functional groups, large interlayer spaces and stable morphologies and when used as anodes in sodium-ion batteries, a reversible sodium intercalation capacity of 248 mAh g-1 was obtained with capacity retention ratio of 91% after 100 cycles at a current density of 100 mA g-1. This large capacity combined with the superior cycling performance indicates that fulvic acid-based carbon nanofibers are promising electrode materials for use in rechargeable sodium-ion batteries.

  4. Electrospun ZnFe{sub 2}O{sub 4}-based nanofiber composites with enhanced supercapacitive properties

    Energy Technology Data Exchange (ETDEWEB)

    Agyemang, Frank Ofori; Kim, Hern, E-mail: hernkim@mju.ac.kr

    2016-09-15

    Highlights: • Electrospun ZnFe{sub 2}O{sub 4}-based nanofibers were successfully fabricated. • The electrochemical properties of ZnFe{sub 2}O{sub 4} were enhanced by addition of ZnO and Fe{sub 2}O{sub 3.} • A specific capacitance of 590 F g{sup −1} was achieved from a CV curve at a scan rate of 5 mV s{sup −1.} • The electrode materials poses excellent cycling stability even after 3000 cycles. - Abstract: Herein, we are reporting a facile method to synthesis ZnFe{sub 2}O{sub 4}-based nanofibers (ZnFe{sub 2}O{sub 4}, ZnO–ZnFe{sub 2}O{sub 4} and Fe{sub 2}O{sub 3}–ZnFe{sub 2}O{sub 4}) via the electrospinning technique using zinc acetonate and ferric acetonate as the metal oxide precursor and polyvinyl pyrrolidone (PVP) as the polymer. The as-prepared electrospun nanofiber composites were calcined at 500 °C to obtain crystalline porous nanofibers. The effect of different compositions on the morphology of each sample as well as their electrochemical properties when employed as electrode materials was studied. The results show that the as-prepared electrodes exhibited excellent performance with their specific capacitances calculated from the CV curves as 590, 490 and 450 F g{sup −1} for Fe{sub 2}O{sub 3}–ZnFe{sub 2}O{sub 4}, ZnO–ZnFe{sub 2}O{sub 4} and ZnFe{sub 2}O{sub 4} respectively at a scan rate of 5 mV s{sup −1}. Excellent stability of the electrodes was also observed even after 3000 cycles. The results obtained suggest these electrode materials might be promising candidates for supercapacitor application.

  5. Electrospun magnetic poly(L-lactide) (PLLA) nanofibers by incorporating PLLA-stabilized Fe3O4 nanoparticles.

    Science.gov (United States)

    Shan, Dingying; Shi, Yuzhou; Duan, Shun; Wei, Yan; Cai, Qing; Yang, Xiaoping

    2013-08-01

    Magnetic poly(L-lactide) (PLLA)/Fe3O4 composite nanofibers were prepared with the purpose to develop a substrate for bone regeneration. To increase the dispersibility of Fe3O4 nanoparticles (NPs) in the PLLA matrix, a modified chemical co-precipitation method was applied to synthesize Fe3O4 NPs in the presence of PLLA. Trifluoroethanol (TFE) was used as the co-solvent for all the reagents, including Fe(II) and Fe(III) salts, sodium hydroxide, and PLLA. The co-precipitated Fe3O4 NPs were surface-coated with PLLA and demonstrated good dispersibility in a PLLA/TFE solution. The composite nanofiber electrospun from the solution displayed a homogeneous distribution of Fe3O4 NPs along the fibers using various contents of Fe3O4 NPs. X-ray diffractometer (XRD) and vibration sample magnetization (VSM) analysis confirmed that the co-precipitation process had minor adverse effects on the crystal structure and saturation magnetization (Ms) of Fe3O4 NPs. The resulting PLLA/Fe3O4 composite nanofibers showed paramagnetic properties with Ms directly related to the Fe3O4 NP concentration. The cytotoxicity of the magnetic composite nanofibers was determined using in vitro culture of osteoblasts (MC3T3-E1) in extracts and co-culture on nanofibrous matrixes. The PLLA/Fe3O4 composite nanofibers did not show significant cytotoxicity in comparison with pure PLLA nanofibers. On the contrary, they demonstrated enhanced effects on cell attachment and proliferation with Fe3O4 NP incorporation. The results suggested that this modified chemical co-precipitation method might be a universal way to produce magnetic biodegradable polyester substrates containing well-dispersed Fe3O4 NPs. This new strategy opens an opportunity to fabricate various kinds of magnetic polymeric substrates for bone tissue regeneration. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Biologically Active Polycaprolactone/Titanium Hybrid Electrospun Nanofibers for Hard Tissue Engineering

    DEFF Research Database (Denmark)

    Barakat, Nasser A. M.; Sheikh, Faheem A.; Al-Deyab, Salem S.

    2011-01-01

    In this study, a novel strategy to improve the bioactivity of polycaprolactone nanofibers is proposed. Incorporation of pure titanium nanoparticles into polycaprolactone nanofibers strongly enhances the precipitation of bone-like apatite materials when the doped nanofibers are soaked in a simulat...... nanofiber mats and the successful incorporation of the titanium nanoparticles make the prepared polycaprolactone nanofiber mat a proper candidate for the hard-tissue engineering applications....

  7. Electrospun PVA/HAp nanocomposite nanofibers: biomimetics of mineralized hard tissues at a lower level of complexity

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gyeong-Man; Asran, Ashraf Sh; Michler, Georg H [Institute of Physics, Martin-Luther-University Halle-Wittenberg, D-06099 Halle/S (Germany); Simon, Paul [Max-Planck Institute for Chemical Physics of Solids, Noethnitzer Strasse 40, D-01187 Dresden (Germany); Kim, Jeong-Sook [Department of Dental Technology, Daegu Health College, 702-722 Daegu (Korea, Republic of)], E-mail: gyeong.kim@physik.uni-halle.de

    2008-12-01

    Based on the biomimetic approaches the present work describes a straightforward technique to mimic not only the architecture (the morphology) but also the chemistry (the composition) of the lowest level of the hierarchical organization of bone. This technique uses an electrospinning (ES) process with polyvinyl alcohol (PVA) and hydroxyapatite (HAp) nanoparticles. To determine morphology, crystalline structures and thermal properties of the resulting electrospun fibers with the pure PVA and PVA/HAp nanocomposite (NC) before electrospinning various techniques were employed, including transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), scanning electron microscopy (SEM), x-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). In addition, FT-IR spectroscopy was carried out to analyze the complex structural changes upon undergoing electrospinning as well as interactions between HAp and PVA. The morphological and crystallographic investigations revealed that the rod-like HAp nanoparticles exhibit a nanoporous morphology and are embedded within the electrospun fibers. A large number of HAp nanorods are preferentially oriented parallel to the longitudinal direction of the electrospun PVA fibers, which closely resemble the naturally mineralized hard tissues of bones. Due to abundant OH groups present in PVA and HAp nanorods, they strongly interact via hydrogen bonding within the electrospun PVA/HAp NC fibers, which results in improved thermal properties. The unique physiochemical features of the electrospun PVA/HAp NC nanofibers prepared by the ES process will open up a wide variety of future applications related to hard tissue replacement and regeneration (bone and dentin), not limited to coating implants.

  8. Multichannel Porous TiO2 Hollow Nanofibers with Rich Oxygen Vacancies and High Grain Boundary Density Enabling Superior Sodium Storage Performance.

    Science.gov (United States)

    Wu, Ying; Jiang, Yu; Shi, Jinan; Gu, Lin; Yu, Yan

    2017-06-01

    TiO2 as an anode for sodium-ion batteries (NIBs) has attracted much recent attention, but poor cyclability and rate performance remain problematic owing to the intrinsic electronic conductivity and the sluggish diffusivity of Na ions in the TiO2 matrix. Herein, a simple process is demonstrated to improve the sodium storage performance of TiO2 by fabricating a 1D, multichannel, porous binary-phase anatase-TiO2 -rutile-TiO2 composite with oxygen-deficient and high grain-boundary density (denoted as a-TiO2-x /r-TiO2-x ) via electrospinning and subsequent vacuum treatment. The introduction of oxygen vacancies in the TiO2 matrix enables enhanced intrinsic electronic conductivity and fast sodium-ion diffusion kinetics. The porous structure offers easy access of the liquid electrolyte and a short transport path of Na+ through the pores toward the TiO2 nanoparticle. Furthermore, the high density of grain boundaries between the anatase TiO2 and rutile TiO2 offer more interfaces for a novel interfacial storage. The a-TiO2-x /r-TiO2-x shows excellent long cycling stability (134 mAh g-1 at 10 C after 4500 cycles) and superior rate performance (93 mAh g-1 after 4500 cycles at 20 C) for sodium-ion batteries. This simple and effective process could serve as a model for the modification of other materials applied in energy storage systems and other fields. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Effect of Saponification Condition on the Morphology and Diameter of the Electrospun Poly(vinyl acetate Nanofibers for the Fabrication of Poly(vinyl alcohol Nanofiber Mats

    Directory of Open Access Journals (Sweden)

    Seong Baek Yang

    2016-10-01

    Full Text Available Novel poly(vinyl alcohol (PVA nanofiber mats were prepared for the first time through heterogeneous saponification of electrospun poly(vinyl acetate (PVAc nanofibers. The effect of varying the saponification conditions, including temperature, time, and concentration of the alkaline solution, on the morphology of the saponified PVA fibers were evaluated by field-emission scanning electron microscopy. At 25 °C, the saponified PVA fibers exhibited a broad diameter distribution. The average fiber diameter, however, was found to decrease with increasing saponification temperature. When the saponification time was increased from 6 to 30 h, the average fiber diameter decreased gradually from 1540 to 1060 nm. In addition, the fiber diameter and morphology were also affected by the concentration of the alkaline saponification solution. The most optimal conditions for fabrication of thin, uniform, and smooth PVA nanofibers corresponded to an alkaline solution containing 10 g each of NaOH, Na2SO4, and methanol per 100 g of water, a temperature of 25 °C, and a saponification time of 24 h.

  10. Electrospun manganese (III) oxide nanofiber based electrochemical DNA-nanobiosensor for zeptomolar detection of dengue consensus primer.

    Science.gov (United States)

    Tripathy, Suryasnata; Krishna Vanjari, Siva Rama; Singh, Vikrant; Swaminathan, S; Singh, Shiv Govind

    2017-04-15

    Nanoscale biosensors, owing to their high-sensitivity and extremely low limits-of-detection, have enabled the realization of highly complex and sophisticated miniaturized platforms for several important healthcare applications, the most predominant one being disease diagnosis. In particular, nanomaterial facilitated electrochemical detection of DNA hybridization has had an exceptional impact on fields such as genetics and cancerous mutation detection Here we report an ultrasensitive electrochemical platform using electrospun semi-conducting Manganese (III) Oxide (Mn 2 O 3 ) nanofibers for DNA Hybridization detection. The proposed platform coalesces the inherent advantages of metal-oxide nanofibers and electrochemical transduction techniques, resulting in label-free zeptomolar detection of DNA hybridization. As proof of concept, we demonstrate zeptomolar detection of Dengue consensus primer (limit of detection: 120×10 -21 M) both in control as well as spiked serum samples. Our reported detection limit is superior in comparison with previously reported electrochemical DNA hybridization sensors for Dengue virus detection, spanning both labeled and label-free transductions. This ultra-sensitivity, we believe, is a result of synthesizing a low bandgap electrospun metal-oxide nanomaterial corresponding to a specific oxidation state of Manganese. This methodology can be extended for detection of any hybridization of interest by simply adapting an appropriate functionalization protocol and thus is very generic in nature. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Carbon nanotubes functionalized electrospun nanofibers formed 3D electrode enables highly strong ECL of peroxydisulfate and its application in immunoassay.

    Science.gov (United States)

    Dai, Hong; Xu, Guifang; Zhang, Shupei; Gong, Lingshan; Li, Xiuhua; Yang, Caiping; Lin, Yanyu; Chen, Jinghua; Chen, Guonan

    2014-11-15

    A new biosensing platform based on electrospun carbon nanotubes nanofibers (CNTs@PNFs) composite, which enabled strong electrochemiluminescent emission of peroxydisulfate, was firstly developed for immunoassay with favorable analytical performances, and then was utilized to evaluate the interaction between antibody and antigen in vitro. Moreover, the obvious ECL image of peroxydisulfate on the prepared sensing platform was firstly recorded in this report. In order to expand the application of peroxydisulfate ECL, the specific recognization biomolecules, α-fetoprotein (AFP) antibody was bound to the functionalized film via electrostatic interaction for fabricating label-free ECL immunosensor to detect α-AFP. Based on the ECL change resulting from the specific immunoreaction between antigen and antibody, the quantitative analysis for AFP with wide dynamic response in the range from 0.1 pg mL(-1) to 160 ng mL(-1) was realized. And the limit of detection was estimated to be 0.09 pg mL(-1). Therefore, the flexible sensing platform not only acted as the sensitized sensing element, but also offered a suitable carrier for immobilization of biological recognition elements with low-toxicity and eco-friendliness, which opened a promising approach to developing further electrospun nanofiber based amplified ECL biosensor with favorable analytical performances. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. In vitro and in vivo evaluation of electrospun nanofibers of PCL, chitosan and gelatin: A comparative study

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, S.R., E-mail: srrg@campus.fct.unl.pt [Centro de Física e Investigação Tecnológica/Departamento de Física Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Rodrigues, G. [Centro de Biologia Ambiental/Departamento de Biologia Animal Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa (Portugal); Martins, G.G. [Centro de Biologia Ambiental/Departamento de Biologia Animal Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749-016 Lisboa (Portugal); Instituto Gulbenkian de Ciência, R. da Quinta Grande, 6, 2780-156 Oeiras (Portugal); Roberto, M.A. [Departamento de Cirurgia Plástica e Reconstrutiva e Unidade de Queimados, Hospital de São José, Rua José António Serrano, 1150-199 Lisboa (Portugal); Mafra, M. [Serviço de Anatomia Patológica, Hospital de São José, Rua José António Serrano, 1150-199 Lisboa (Portugal); Henriques, C.M.R. [Centro de Física e Investigação Tecnológica/Departamento de Física Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); and others

    2015-01-01

    Many polymers have been investigated with respect to their use in skin tissue engineering. However, directly comparable data on the role played by different polymers in assisting skin wound healing requires their in vitro and in vivo evaluation under the same conditions. Therefore, we performed a study in order to compare the performance of electrospun nanofiber mats from three different polymers concerning cell–scaffold interaction and wound healing promotion. A polyester (polycaprolactone, PCL), a protein (gelatin from cold water fish skin, GEL) and a polysaccharide (chitosan, CS) were the polymers chosen. Gelatin nanofibers were crosslinked with glutaraldehyde vapor. The scaffolds were characterized physico-chemically, in vitro by seeding with human fetal fibroblasts, HFFF2, and used in vivo as skin substitutes in a rat wound model with total skin removal. In vitro tests revealed that cells adhered and proliferated in all scaffolds. However, cells deep into the scaffold were only observed in the PCL and CS scaffolds. In in vivo tests CS scaffolds had the highest impact on the healing process by decreasing the extent of wound contraction and enhancing the production of a neodermis and re-epithelialization of the wound. - Highlights: • We produced and compared the properties of electrospun PCL, CS and fish GEL. • In vitro, cells adhered and proliferated better on GEL scaffolds. • Deep cell migration was observed in the PCL and CS matrices. • In vivo, both CS and GEL matrices integrated well within the wounds. • Only CS effectively blocked, although only partially, the contraction phenomenon.

  13. Effect of Wrapped Carbon Nanotubes on Optical Properties, Morphology, and Thermal Stability of Electrospun Poly(vinyl alcohol Composite Nanofibers

    Directory of Open Access Journals (Sweden)

    Naoual Diouri

    2013-01-01

    Full Text Available Electrospinning was used to elaborate poly(vinyl alcohol (PVA nanofibers in the presence of embedded multiwall carbon nanotubes (MWCNTs in surfactant and polymer. MWCNTs were dispersed in aqueous solution using both sodium dodecyl sulfate (SDS as surfactant and Poly(vinyl pyrrolidone (PVP. Changing the surfactant and polymer concentration reveals that the maximum dispersion achievable is corresponding to the mass ratios MWCNTs : SDS—1 : 5 and MWCNTs : SDS : PVP—1 : 5 : 0.6 in the presence of the PVP. After the optimization of the dispersion process, the SEM image of the PVA/PVP/SDS/MWCNTs electrospun fibers presents high stability of the fibers with diameter around 224 nm. Infrared spectroscopy and thermal gravimetric analysis elucidate the type of interaction between the PVA and the coated carbon nanotube. The presence of PVP wrapped carbon nanotubes reduced slightly the onset of the degradation temperature of the electrospun nanofibers.

  14. Engineering Multi-scale Electrospun Structure for Integration into Architected 3-D Nanofibers for Cimex Annihilation: Fabrication and Mechanism Study

    Science.gov (United States)

    He, Shan; Zhang, Linxi; Liu, Ying; Rafailovich, Miriam; Garcia CenterPolymers at Engineered Interfaces Team

    In this study, engineered electrospun scaffolds with fibers oriented with designed curvature in three dimensions (3D) including the looped structure were developed based on the principle of electrostatic repulsion. Here we illustrate that 3D electrospun recycled polystyrene fibers could closely mimic the unique architectures of multi-direction and multi-layer nano-spiderweb. In contrast to virgin PS, the recycled PS (Dart Styrofoam) are known to contain zinc stearate which acts as a surfactant resulting in higher electrical charge and larger fiber curvature, hence, lower modulus. The surfactant, which is known to decrease the surface tension, may have also been effective at decreasing the confinement of the PS, where chain stretching was shown to occur, in response to the high surface tension at the air interface. Three dimensional flexible architecture with complex structures are shown to be necessary in order to block the motion of Cimex lectularius. Here we show how an engineered electrospun network of surfactant modified polymer fibers with calculated dimensions can be used to immobilize the insects. The mechanical response of the fibers has to be specifically tailored so that it is elastically deformed, without fracturing or flowing. Carefully controlling and tailoring the electrospinning parameters we can now utilize architected 3D nanofiber to create an environmental-friendly Cimex immobilization device which can lead to annihilation solution for all the other harmful insects.

  15. Electrospun ion gel nanofibers for flexible triboelectric nanogenerator: electrochemical effect on output power.

    Science.gov (United States)

    Ye, Byeong Uk; Kim, Byoung-Joon; Ryu, Jungho; Lee, Joo Yul; Baik, Jeong Min; Hong, Kihyon

    2015-10-21

    A simple fabrication route for ion gel nanofibers in a triboelectric nanogenerator was demonstrated. Using an electrospinning technique, we could fabricate a large-area ion gel nanofiber mat. The triboelectric nanogenerator was demonstrated by employing an ion gel nanofiber and the device exhibited an output power of 0.37 mW and good stability under continuous operation.

  16. Design of an efficient photoanode for dye-sensitized solar cells using electrospun one-dimensional GO/N-doped nanocomposite SnO2/TiO2

    Science.gov (United States)

    Mohamed, Ibrahim M. A.; Dao, Van-Duong; Yasin, Ahmed S.; Barakat, Nasser A. M.; Choi, Ho-Suk

    2017-04-01

    This study presents the combination of N, graphene oxide (GO) and SnO2 as efficient dopants into TiO2 nanofibers (NFs) photoanode substrate for highly efficient dye-sensitized solar cells (DSCs). The developed NFs are synthesized by electrospinning and hydrothermal processes and characterized by FESEM, TEM, XPS, FT-IR, Raman and EDX-studies. The formation of short NFs is confirmed through FESEM and TEM measurements. As the results, the major crystal structure of TiO2 in the prepared NFs has anatase (85.23%) and rutile-structure (14.67%). XPS and EDX studies affirm that the material has Ti, O, Sn, N and C elements. In addition, FT-IR and Raman spectra give an indication about the GO-content. Typically, the DSC based on the novel NFs shows 6.18% efficiency. The Jsc, Voc, FF and Rct are estimated and found to be 10.32 mA cm-2, 0.825 V, 0.73 and 21.66 Ω, respectively. The high-power efficiency is contributed by three reasons. The first one is the high dye-loading (2.16 × 10-7 mol cm-2). The second reason is the enhanced charge transfer and decreasing of the electrons/holes recombination through formation of wide band-gap oxide (3.246 eV). Finally, the third one is GO-doping which may create new routes for the electron transfer in working electrode layer.

  17. Preparation and in vivo efficient anti-infection property of GTR/GBR implant made by metronidazole loaded electrospun polycaprolactone nanofiber membrane.

    Science.gov (United States)

    Xue, Jiajia; He, Min; Niu, Yuzhao; Liu, Hao; Crawford, Aileen; Coates, Phil; Chen, Dafu; Shi, Rui; Zhang, Liqun

    2014-11-20

    Infection is the major reason of GTR/GBR membrane failure in clinical application. In this work, we developed GTR/GBR nanofiber membranes with localized drug delivery function to prevent infection. Metronidazole (MNA), an antibiotic, was successfully incorporated into electrospun polycaprolactone (PCL) nanofibers at different concentrations (0, 1, 5, 10, 20, 30, and 40 wt% polymer). To obtain the optimum anti-infection membrane, we systematically investigated the physical-chemical and mechanical properties of the nanofiber membranes with different drug contents. The interaction between PCL and MNA was identified by molecular dynamics simulation. MNA released in a controlled, sustained manner over 2 weeks and the antibacterial activity of the released MNA remained. The incorporation of MNA improved the hydrophilicity and in vitro biodegradation rate of PCL nanofibers. The nanofiber membranes allowed cells to adhere to and proliferate on them and showed excellent barrier function. The membrane loaded with 30% MNA had the best comprehensive properties. Analysis of subcutaneous implants demonstrated that MNA-loaded nanofibers evoked a less severe inflammatory response than pure PCL nanofibers. These results demonstrate the potential of MNA-loaded nanofiber membranes as GTR/GBR membrane with antibacterial and anti-inflammatory function for extensive biomedical applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Influence of layer-by-layer assembled electrospun poly (L-lactic acid) nanofiber mats on the bioactivity of endothelial cells

    Science.gov (United States)

    Wu, Keke; Zhang, Xiazhi; Yang, Wufeng; Liu, Xiaoyan; Jiao, Yanpeng; Zhou, Changren

    2016-12-01

    Electrospun poly(L-lactic acid) (PLLA) nanofiber mats were successfully modified by deposition of multilayers with chitosan (CS), heparin (Hep) and graphene oxide (GO) through electrostatic layer-by-layer (LBL) self-assembly method. In this study, the surface properties of PLLA nanofiber mats before and after modification were investigated via scanning electron microscope (SEM), atomic force microscopy (AFM), attenuated total reflectance fourier transformation infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and water contact angle measurement. In addition, the cytocompatibility of the modified PLLA nanofiber mats were investigated by testing endothelial cells compatibility, including cell attachment, cell proliferation and cell cycle. The results revealed that the surfaces of modified PLLA nanofiber mats become much rougher, stifiness and the hydrophilicity of the LBL modified PLLA nanofiber mats were improved compared to original PLLA one. Moreover, the modified PLLA nanofiber mats had promoted the endothelial cells viability attachment significantly. Besides, we studied the PLLA nanofiber mats on the expression of necrosis factor (TNF-α), interleukine-1β (IL-1β), monocyte chemoattractant protein-1 (MCP-1) and vascular cell adhesion molecule-1 (VCAM-1) in endothelial cells. The results showed that modified PLLA nanofiber mats had inhibited the inflammatory response to some extent.

  19. Comparative performance of collagen nanofibers electrospun from different solvents and stabilized by different crosslinkers.

    Science.gov (United States)

    Fiorani, Andrea; Gualandi, Chiara; Panseri, Silvia; Montesi, Monica; Marcacci, Maurilio; Focarete, Maria Letizia; Bigi, Adriana

    2014-10-01

    Collagen electrospun scaffolds well reproduce the structure of the extracellular matrix (ECM) of natural tissues by coupling high biomimetism of the biological material with the fibrous morphology of the protein. Structural properties of collagen electrospun fibers are still a debated subject and there are conflicting reports in the literature addressing the presence of ultrastructure of collagen in electrospun fibers. In this work collagen type I was successfully electrospun from two different solvents, trifluoroethanol (TFE) and dilute acetic acid (AcOH). Characterization of collagen fibers was performed by means of SEM, ATR-IR, Circular Dichroism and WAXD. We demonstrated that collagen fibers contained a very low amount of triple helix with respect to pristine collagen (18 and 16% in fibers electrospun from AcOH and TFE, respectively) and that triple helix denaturation occurred during polymer dissolution. Collagen scaffolds were crosslinked by using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC), a commonly employed crosslinker for electrospun collagen, and 1,4-butanediol diglycidyl ether (BDDGE), that was tested for the first time in this work as crosslinking agent for collagen in the form of electrospun fibers. We demonstrated that BDDGE successfully crosslinked collagen and preserved at the same time the scaffold fibrous morphology, while scaffolds crosslinked with EDC completely lost their porous structure. Mesenchymal stem cell experiments demonstrated that collagen scaffolds crosslinked with BDDGE are biocompatible and support cell attachment.

  20. Two-stage desorption-controlled release of fluorescent dye and vitamin from solution-blown and electrospun nanofiber mats containing porogens.

    Science.gov (United States)

    Khansari, S; Duzyer, S; Sinha-Ray, S; Hockenberger, A; Yarin, A L; Pourdeyhimi, B

    2013-12-02

    In the present work, a systematic study of the release kinetics of two embedded model drugs (one completely water soluble and one partially water soluble) from hydrophilic and hydrophobic nanofiber mats was conducted. Fluorescent dye Rhodamine B was used as a model hydrophilic drug in controlled release experiments after it was encapsulated in solution-blown soy-protein-containing hydrophilic nanofibers as well as in electrospun hydrophobic poly(ethylene terephthalate) (PET)-containing nanofibers. Vitamin B2 (riboflavin), a partially water-soluble model drug, was also encapsulated in hydrophobic PET-containing nanofiber mats, and its release kinetics was studied. The nanofiber mats were submerged in water, and the amount of drug released was tracked by fluorescence intensity. It was found that the release process saturates well below 100% release of the embedded compound. This is attributed to the fact that desorption is the limiting process in the release from biopolymer-containing nanofibers similar to the previously reported release from petroleum-derived polymer nanofibers. Release from monolithic as well as core-shell nanofibers was studied in the present work. Moreover, to facilitate the release and ultimately to approach 100% release, we also incorporated porogens, for example, poly(ethylene glycol), PEG. It was also found that the release rate can be controlled by the porogen choice in nanofibers. The effect of nanocracks created by leaching porogens on drug release was studied experimentally and evaluated theoretically, and the physical parameters characterizing the release process were established. The objective of the present work is a detailed experimental and theoretical investigation of controlled drug release from nanofibers facilitated by the presence of porogens. The novelty of this work is in forming nanofibers containing biodegradable and biocompatible soy proteins to facilitate controlled drug release as well as in measuring detailed

  1. A surface acoustic wave humidity sensor with high sensitivity based on electrospun MWCNT/Nafion nanofiber films

    Science.gov (United States)

    Sheng, Lei; Dajing, Chen; Yuquan, Chen

    2011-07-01

    Humidity detection has been widely used in a variety of fields. A humidity sensor with high sensitivity is reported in this paper. A surface acoustic wave resonator (SAWR) with high resonance frequency was fabricated as a basic sensitive component. Various nanotechnologies were used to improve the sensor's performance. A multi-walled carbon nanotube/Nafion (MWCNT/Nafion) composite material was prepared as humidity-sensitive films, deposited on the surface of an SAWR by the electrospinning method. The electrospun MWCNT/Nafion nanofiber films showed a three-dimensional (3D) porous structure, which was profitable for improving the sensor's performance. The new nano-water-channel model of Nafion was also applied in the humidity sensing process. Compared to other research, the present sensor showed excellent sensitivity (above 400 kHz/% relative humidity (RH) in the range from 10% RH to 80% RH), good linearity (R2 > 0.98) and a short response time (~3 s@63%).

  2. Superhydrophilic graphene oxide@electrospun cellulose nanofiber hybrid membrane for high-efficiency oil/water separation.

    Science.gov (United States)

    Ao, Chenghong; Yuan, Wei; Zhao, Jiangqi; He, Xu; Zhang, Xiaofang; Li, Qingye; Xia, Tian; Zhang, Wei; Lu, Canhui

    2017-11-01

    Inspired from fishscales, membranes with special surface wettability have been applied widely for the treatment of oily waste water. Herein, a novel superhydrophilic graphene oxide (GO)@electrospun cellulose nanofiber (CNF) membrane was successfully fabricated. This membrane exhibited a high separation efficiency, excellent antifouling properties, as well as a high flux for the gravity-driven oil/water separation. Moreover, the GO@CNF membrane was capable to effectively separate oil/water mixtures in a broad pH range or with a high concentration of salt, suggesting that this membrane was quite promising for future real-world practice in oil spill cleanup and oily wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. A surface acoustic wave humidity sensor with high sensitivity based on electrospun MWCNT/Nafion nanofiber films.

    Science.gov (United States)

    Sheng, Lei; Dajing, Chen; Yuquan, Chen

    2011-07-01

    Humidity detection has been widely used in a variety of fields. A humidity sensor with high sensitivity is reported in this paper. A surface acoustic wave resonator (SAWR) with high resonance frequency was fabricated as a basic sensitive component. Various nanotechnologies were used to improve the sensor's performance. A multi-walled carbon nanotube/Nafion (MWCNT/Nafion) composite material was prepared as humidity-sensitive films, deposited on the surface of an SAWR by the electrospinning method. The electrospun MWCNT/Nafion nanofiber films showed a three-dimensional (3D) porous structure, which was profitable for improving the sensor's performance. The new nano-water-channel model of Nafion was also applied in the humidity sensing process. Compared to other research, the present sensor showed excellent sensitivity (above 400 kHz/% relative humidity (RH) in the range from 10% RH to 80% RH), good linearity (R(2) > 0.98) and a short response time (∼3 s@63%).

  4. Electrospun Polycaprolactone/Polylactic Acid Nanofibers as an Artificial Nerve Conduit

    Directory of Open Access Journals (Sweden)

    Zeeshan Ali Khatri

    2014-07-01

    Full Text Available Development of conduits made of biodegradable nanofibers is gaining substantial interest due to their suitability for nerve regeneration. Among all polymeric nanofibers PCL (Poly ?-Caprolactone is distinctively found for mechanical stability and PLLA (Poly (L-Lactic Acid for relatively faster biodegradability. The aim of this study is to investigate blending compatibility between PCL and PLLA and the ability to fabricate nanofibers conduits via electro spinning. The PCL-PLLA nano-fiber tubular made from different blend ratios of PCL-PLLA were electro spun. The electro spun nanofibers were continuously deposited over high speed rotating mandrel to fabricate nanofibers conduit having inner diameter of 2mm and the wall thickness of 55-65µm. The diameters of nano-fibers were between 715-860nm. FTIR (Fourier Transform Infrared spectroscopy used to analyze chemical change in the blends of nerve conduits, which revealed that the PCL-PLLA blend nanofiber exhibit characteristic peaks of both PCL and PLLA and was composition dependent. The crystallinity of PCL-PLLA tubes were studied using WAXD (Wide Angle Xray Diffraction. The morphology of nanofibers were investigated under SEM (Scanning Electron Microscope. The mechanical properties of the conduits were also tested; the Young?s modulus obtained for small diameter was 10MPa, twice as high as larger diameter.

  5. Novel electrospun gelatin/oxycellulose nanofibers as a suitable platform for lung disease modeling

    Energy Technology Data Exchange (ETDEWEB)

    Švachová, Veronika, E-mail: xcsvachova@fch.vutbr.cz [Institute of Materials Chemistry, Brno University of Technology (Czech Republic); Vojtová, Lucy [CEITEC – Central European Institute of Technology, Brno University of Technology (Czech Republic); SCITEG, a.s., Brno (Czech Republic); Pavliňák, David [Department of Physical Electronics, Masaryk University (Czech Republic); Vojtek, Libor [Institute of Experimental Biology, Masaryk University (Czech Republic); Sedláková, Veronika [Department of Histology and Embryology, Masaryk University (Czech Republic); International Clinical Research, St. Anne' s University Hospital, Brno (Czech Republic); Hyršl, Pavel [Institute of Experimental Biology, Masaryk University (Czech Republic); Alberti, Milan [Department of Physical Electronics, Masaryk University (Czech Republic); Jaroš, Josef; Hampl, Aleš [Department of Histology and Embryology, Masaryk University (Czech Republic); International Clinical Research, St. Anne' s University Hospital, Brno (Czech Republic); Jančář, Josef [Institute of Materials Chemistry, Brno University of Technology (Czech Republic); CEITEC – Central European Institute of Technology, Brno University of Technology (Czech Republic); SCITEG, a.s., Brno (Czech Republic)

    2016-10-01

    Novel hydrolytically stable gelatin nanofibers modified with sodium or calcium salt of oxycellulose were prepared by electrospinning method. The unique inhibitory effect of these nanofibers against Escherichia coli bacteria was examined by luminometric method. Biocompatibility of these gelatin/oxycellulose nanofibers with eukaryotic cells was tested using human lung adenocarcinoma cell line NCI-H441. Cells firmly adhered to nanofiber surface, as determined by scanning electron microscopy, and no signs of cell dying were detected by fluorescent live/dead assay. We propose that the newly developed gelatin/oxycellulose nanofibers could be used as promising scaffold for lung disease modeling and anti-cancer drug testing. - Highlights: • Novel hydrolytically stable gelatin nanofibers modified with oxycellulose were prepared by electrospinning. • ATR–FTIR spectroscopy and EDX confirmed the presence of oxycellulose in the nanofibers. • Nanofibers modified with calcium salt of oxycellulose exhibited significant antibacterial properties. • Nanofibers modified with sodium salt of oxycellulose revealed excellent biocompatibility with cell line NCI-H441.

  6. Performance of electro-spun carbon nanofiber electrodes with conductive poly(3,4-ethylenedioxythiophene) coatings in bioelectrochemical systems

    Science.gov (United States)

    Guzman, Juan J. L.; Pehlivaner Kara, Meryem O.; Frey, Margaret W.; Angenent, Largus T.

    2017-07-01

    Bioelectrochemical systems (BESs) employ extracellular electron transfer from bacteria that grow at electrodes. Due to biofilm and electrode limitations, industrial-scale applications require large electrode areas, and thus inexpensive electrode materials. Here, electro-spun polyacrylonitrile (PAN) and carbon nanofiber (CNF) were manufactured. In addition, the conductive polymer poly(3,4-ethylenedioxythiophene) (PEDOT) was applied as a coating to these materials and to carbon cloth (CC). We tested these materials as electrodes by using physicochemical measurements, cyclic voltammetry, and bioelectrochemical growth-studies with Geobacter sulfurreducens. PAN is a nonconductive material without capacitance, but with PEDOT coating the conductivity and capacitance became sufficient to support electric current production in our BES. CNF outperformed CC in capacitance, but behaved similarly in our BES when normalized to projected surface area. With the PEDOT coating, CNF increased electric current production by 38% in our BES, while this was 64% for CC. When applied to a gold microfluidic electrode, electric current with G. sulfurreducens increased almost three-fold. PEDOT added considerable specific surface area to electrodes possessing a low surface area, but not with a high surface area such as CNF. This work demonstrates that electro-spun electrodes and PEDOT coating are a promising electrode alternative that can be readily implemented into existing BESs.

  7. Effects of Ce doping and humidity on UV sensing properties of electrospun ZnO nanofibers

    Science.gov (United States)

    Liu, Yan-Jie; Zhang, Hong-Di; Zhang, Jun; Li, Shuo; Zhang, Jun-Cheng; Zhu, Jian-Wei; Gong, Mao-Gang; Wang, Xiao-Xiong; Long, Yun-Ze

    2017-09-01

    Pure ZnO and Ce-doped ZnO nanofibers were synthesized via electrospinning-calcination technique. The morphology, composition, structure, humidity sensing and photoelectric properties were characterized. The field-effect curves showed that a single pure ZnO nanofiber is an n-type semiconductor and an individual Ce-ZnO nanofiber is a p-type semiconductor. The Ce doping and humidity have strong influence on the UV sensing properties of ZnO-based nanofibers. In the dark, the responses [(IVarious RH - I43% RH)/I43% RH] of pure ZnO increased gradually with the increase of humidity, while the responses of Ce-doped ZnO nanofibers decreased. When exposed to UV radiation, the response of pure ZnO nanofibers decreased with increasing humidity, while that of Ce-doped ZnO increased. And the highest responses are around 88.44 and 683.67 at 97% humidity for pure ZnO and Ce-ZnO nanofibers under UV irradiation. In addition, the UV response of Ce-ZnO with good stability and repeatability increases by two orders of magnitude than that of pure ZnO. The sensing mechanism relevant to oxygen and water-related conduction was discussed briefly. These results exhibit that the application prospects of p-type Ce-ZnO nanofibers are promising in the field of photoelectric devices.

  8. Electrospun polyimide nanofiber-based nonwoven separators for lithium-ion batteries

    Science.gov (United States)

    Miao, Yue-E.; Zhu, Guan-Nan; Hou, Haoqing; Xia, Yong-Yao; Liu, Tianxi

    2013-03-01

    Polyimide (PI) nanofiber-based nonwovens have been fabricated via electrospinning for the separators of lithium-ion batteries (LIBs). Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and hot oven tests show that the PI nanofiber-based nonwovens are thermally stable at a high temperature of 500 °C while the commercial Celgard membrane exhibits great shrinkage at 150 °C and even goes melting over 167 °C, indicating a superior thermal stability of PI nanofiber-based nonwovens than that of the Celgard membrane. Moreover, the PI nanofiber-based nonwovens exhibit better wettability for the polar electrolyte compared to the Celgard membrane. The PI nanofiber-based nonwoven separators are also evaluated to have higher capacity, lower resistance and higher rate capability compared to the Celgard membrane separator, which proves that they are ideal candidates for separators of high-performance rechargeable LIBs.

  9. Experimental Investigation of the Properties of Electrospun Nanofibers for Potential Medical Application

    Directory of Open Access Journals (Sweden)

    Anhui Wang

    2015-01-01

    Full Text Available Polymer based nanofibers using ethylene-co-vinyl alcohol (EVOH were fabricated by electrospinning technology. The nanofibers were studied for potential use as dressing materials for skin wounds treatment. Properties closely related to the clinical requirements for wound dressing were investigated, including the fluid uptake ability (FUA, the water vapour transmission rate (WVTR, the bacteria control ability of nanofibers encapsulated with different antibacterial drugs, and Ag of various concentrations. Nanofibre degradation under different environmental conditions was also studied for the prospect of long term usage. The finding confirms the potential of EVOH nanofibers for wound dressing application, including the superior performance compared to cotton gauze and the strong germ killing capacity when Ag particles are present in the nanofibers.

  10. Electric field induced orientation of polymer chains in macroscopically aligned electrospun polymer nanofibers.

    Science.gov (United States)

    Kakade, Meghana V; Givens, Steven; Gardner, Kenncorwin; Lee, Keun Hyung; Chase, D Bruce; Rabolt, John F

    2007-03-14

    The results presented in this work show for the first time that an electric field used to macroscopically align polymer nanofibers can also align polymer chains parallel to the fiber axis. This important result indicates that anisotropic structural properties (mechanical, electrical, etc.) can be induced in polymer nanofibers during the electrospinning process. Such uniaxially oriented nanofibers exhibit a variety of potential applications in biomedicine, microelectronics, and optics. A simple technique of vertical electrospinning with an electric field induced, stationary collection was employed to obtain the molecular orientation in polymer nanofibers. This manuscript describes the orientation process via electrospinning and verifies this molecular orientation in the polymer nanofibers using three independent methods: polarized Fourier transform infrared spectroscopy, polarized Raman scattering, and X-ray diffraction.

  11. Mussel inspired protein-mediated surface functionalization of electrospun nanofibers for pH-responsive drug delivery

    Science.gov (United States)

    Jiang, Jiang; Xie, Jingwei; Ma, Bing; Bartlett, David E.; Xu, An; Wang, Chi-Hwa

    2014-01-01

    pH-responsive drug delivery systems could mediate drug releasing rate by changing pH values at specific time as per the pathophysiological need of the disease. Herein, we demonstrated a mussel inspired protein polydopamine coating can tune the loading and releasing rate of charged molecules from electrospun poly (ε-caprolactone) (PCL) nanofibers in solutions with different pH values. In vitro release profiles showed that the positive charged molecules released significantly faster in acidic than those in neutral and basic environments within the same incubation time. The results of fluorescein diacetate staining and 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays showed the viability of cancer cells after treatment with doxorubicin released media at different pH values qualitatively and quantitatively, indicating the media contained doxorubicin which was released in solutions at low pH values could kill significantly higher number of cells than that released in solutions at high pH values. Together, the pH-responsive drug delivery systems based on polydopamine-coated PCL nanofibers could have potential applications in oral delivery of anticancer drugs for treating gastric cancer and vaginal delivery of anti-viral drugs or anti-inflammatory drugs, which could raise their efficacy, deliver them to the specific target, and minimize their toxic side effects. PMID:24287161

  12. Single Light Emitters in Electrospun Polymer Nanofibers: Effect of Local Confinement on Radiative Decay

    NARCIS (Netherlands)

    Tomczak, N.; Gu, S.; Gu, Shuying; Han, Mingyong; van Hulst, N.F.; Vancso, Gyula J.

    2006-01-01

    The fabrication of light emitting polymer nanofibers by electrospinning of polymer solutions containing either fluorescent organic dye molecules or luminescent semiconductor nanoparticles (quantum dots) is presented. The fluorescence spectra and lifetime of the embedded emitters, down to the level

  13. Ablation characteristics of electrospun core-shell nanofiber by femtosecond laser.

    Science.gov (United States)

    Park, ChangKyoo; Xue, Ruipeng; Lannutti, John J; Farson, Dave F

    2016-08-01

    This study examined the femtosecond laser ablation properties of core and shell polymers their relationship to the ablation characteristics of core-shell nanofibers. The single-pulse ablation threshold of bulk polycaprolactone (PCL) was measured to be 2.12J/cm(2) and that of bulk polydimethylsiloxane (PDMS) was 4.07J/cm(2). The incubation coefficients were measured to be 0.82±0.02 for PCL and 0.53±0.03 for PDMS. PDMS-PCL core-shell and pure PCL nanofibers were fabricated by electrospinning. The energy/volume of pure PCL and PDMS-PCL core-shell nanofiber ablation was investigated by measuring linear ablation grooves made at different scanning speeds. At large scanning speed, higher energy/volume was required for machining PDMS-PCL nanofiber than for PCL nanofiber. However, at small scanning speed, comparable energy/volume was measured for PDMS-PCL and PCL nanofiber ablation. Additionally, in linear scanned ablation of PDMS-PCL fibers at small laser pulse energy and large scanning speed, there were partially ablated fibers where the shell was ablated but the core remained. This was attributed to the lower ablation threshold of the shell material. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Preparation of Aligned Ultra-long and Diameter-controlled Silicon Oxide Nanotubes by Plasma Enhanced Chemical Vapor Deposition Using Electrospun PVP Nanofiber Template

    Directory of Open Access Journals (Sweden)

    Zhou Ming

    2009-01-01

    Full Text Available Abstract Well-aligned and suspended polyvinyl pyrrolidone (PVP nanofibers with 8 mm in length were obtained by electrospinning. Using the aligned suspended PVP nanofibers array as template, aligned ultra-long silicon oxide (SiOx nanotubes with very high aspect ratios have been prepared by plasma-enhanced chemical vapor deposition (PECVD process. The inner diameter (20–200 nm and wall thickness (12–90 nm of tubes were controlled, respectively, by baking the electrospun nanofibers and by coating time without sacrificing the orientation degree and the length of arrays. The micro-PL spectrum of SiOx nanotubes shows a strong blue–green emission with a peak at about 514 nm accompanied by two shoulders around 415 and 624 nm. The blue–green emission is caused by the defects in the nanotubes.

  15. Properties of Electrospun Nanofibers of Multi-Block Copolymers of [Poly-ε-caprolactone-b-poly(tetrahydrofuran-co-ε-caprolactone]m Synthesized by Janus Polymerization

    Directory of Open Access Journals (Sweden)

    Muhammad Ijaz Shah

    2017-10-01

    Full Text Available Novel biodegradable multiblock copolymers of [PCL-b-P(THF-co-CL]m with PCL fractions of 53.3 and 88.4 wt % were prepared by Janus polymerization of ε-caprolactone (CL and tetrahydrofuran (THF. Their electrospun mats were obtained with optimized parameters containing bead-free nanofibers whose diameters were between 290 and 520 nm. The mechanical properties of the nanofiber scaffolds were measured showing the tensile strength and strain at break of 8–10 MPa and 123–161%, respectively. Annealing improved their mechanical properties and their tensile strength and strain at break of the samples increased to 10–13 MPa and 267–338%, respectively. Due to the porous structure and crystallization in nanoscale confinement, the mechanical properties of the nanofiber scaffolds appeared as plastics, rather than as the elastomers observed in bulk thermal-molded film.

  16. Poly(methyl vinyl ether-alt-maleic acid) and ethyl monoester as building polymers for drug-loadable electrospun nanofibers.

    Science.gov (United States)

    Mira, Amalia; Mateo, C Reyes; Mallavia, Ricardo; Falco, Alberto

    2017-12-08

    New biomaterials are sought for the development of bioengineered nanostructures. In the present study, electrospun nanofibers have been synthesized by using poly(methyl vinyl ether-alt-maleic acid) and poly(methyl vinyl ether-alt-maleic ethyl monoester) (PMVEMA-Ac and PMVEMA-ES, respectively) as building polymers for the first time. To further functionalize these materials, nanofibers of PMVEMA-Ac and PMVEMA-ES containing a conjugated polyelectrolyte (HTMA-PFP, blue emitter, and HTMA-PFNT, red emitter) were achieved with both forms maintaining a high solid state fluorescence yield without altered morphology. Also, 5-aminolevulinic acid (5-ALA) was incorporated within these nanofibers, where it remained chemically stable. In all cases, nanofiber diameters were less than 150 nm as determined by scanning and transmission electron microscopy, and encapsulation efficiency of 5-ALA was 97 ± 1% as measured by high-performance liquid chromatography. Both polymeric matrices showed rapid release kinetics in vertical cells (Franz cells) and followed Higuchi kinetics. In addition, no toxicity of nanofibers, in the absence of light, was found in HaCaT and SW480 cell lines. Finally, it was shown that loaded 5-ALA was functional, as it was internalized by cells in nanofiber-treated cultures and served as a substrate for the generation of protoporphyrin IX, suggesting these pharmaceutical vehicles are suitable for photodynamic therapy applications.

  17. Electrospun Gelatin/β-TCP Composite Nanofibers Enhance Osteogenic Differentiation of BMSCs and In Vivo Bone Formation by Activating Ca2+-Sensing Receptor Signaling

    Directory of Open Access Journals (Sweden)

    Xuehui Zhang

    2015-01-01

    Full Text Available Calcium phosphate- (CaP- based composite scaffolds have been used extensively for the bone regeneration in bone tissue engineering. Previously, we developed a biomimetic composite nanofibrous membrane of gelatin/β-tricalcium phosphate (TCP and confirmed their biological activity in vitro and bone regeneration in vivo. However, how these composite nanofibers promote the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs is unknown. Here, gelatin/β-TCP composite nanofibers were fabricated by incorporating 20 wt% β-TCP nanoparticles into electrospun gelatin nanofibers. Electron microscopy showed that the composite β-TCP nanofibers had a nonwoven structure with a porous network and a rough surface. Spectral analyses confirmed the presence and chemical stability of the β-TCP and gelatin components. Compared with pure gelatin nanofibers, gelatin/β-TCP composite nanofibers caused increased cell attachment, proliferation, alkaline phosphatase activity, and osteogenic gene expression in rat BMSCs. Interestingly, the expression level of the calcium-sensing receptor (CaSR was significantly higher on the composite nanofibrous scaffolds than on pure gelatin. For rat calvarial critical sized defects, more extensive osteogenesis and neovascularization occurred in the composite scaffolds group compared with the gelatin group. Thus, gelatin/β-TCP composite scaffolds promote osteogenic differentiation of BMSCs in vitro and bone regeneration in vivo by activating Ca2+-sensing receptor signaling.

  18. Electrospun Gelatin/β-TCP Composite Nanofibers Enhance Osteogenic Differentiation of BMSCs and In Vivo Bone Formation by Activating Ca (2+) -Sensing Receptor Signaling.

    Science.gov (United States)

    Zhang, Xuehui; Meng, Song; Huang, Ying; Xu, Mingming; He, Ying; Lin, Hong; Han, Jianmin; Chai, Yuan; Wei, Yan; Deng, Xuliang

    2015-01-01

    Calcium phosphate- (CaP-) based composite scaffolds have been used extensively for the bone regeneration in bone tissue engineering. Previously, we developed a biomimetic composite nanofibrous membrane of gelatin/β-tricalcium phosphate (TCP) and confirmed their biological activity in vitro and bone regeneration in vivo. However, how these composite nanofibers promote the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) is unknown. Here, gelatin/β-TCP composite nanofibers were fabricated by incorporating 20 wt% β-TCP nanoparticles into electrospun gelatin nanofibers. Electron microscopy showed that the composite β-TCP nanofibers had a nonwoven structure with a porous network and a rough surface. Spectral analyses confirmed the presence and chemical stability of the β-TCP and gelatin components. Compared with pure gelatin nanofibers, gelatin/β-TCP composite nanofibers caused increased cell attachment, proliferation, alkaline phosphatase activity, and osteogenic gene expression in rat BMSCs. Interestingly, the expression level of the calcium-sensing receptor (CaSR) was significantly higher on the composite nanofibrous scaffolds than on pure gelatin. For rat calvarial critical sized defects, more extensive osteogenesis and neovascularization occurred in the composite scaffolds group compared with the gelatin group. Thus, gelatin/β-TCP composite scaffolds promote osteogenic differentiation of BMSCs in vitro and bone regeneration in vivo by activating Ca(2+)-sensing receptor signaling.

  19. Grafting of gelatin on electrospun poly(caprolactone) nanofibers to improve endothelial cell spreading and proliferation and to control cell Orientation.

    Science.gov (United States)

    Ma, Zuwei; He, Wei; Yong, Thomas; Ramakrishna, S

    2005-01-01

    We modified the surface of electrospun poly(caprolactone) (PCL) nanofibers to improve their compatibility with endothelial cells (ECs) and to show the potential application of PCL nanofibers as a blood vessel tissue-engineering scaffold. Nonwoven PCL nanofibers (PCL NF) and aligned PCL nanofibers (APCL NF) were fabricated by electrospinning technology. To graft gelatin on the nanofiber surface, PCL nanofibers were first treated with air plasma to introduce -COOH groups on the surface, followed by covalent grafting of gelatin molecules, using water-soluble carbodiimide as the coupling agent. The chemical change in the material surface during surface modification was confirmed by X-ray photoelectron spectroscopy and quantified by colorimetric methods. ECs were cultured to evaluate the cytocompatibility of surface-modified PCL NF and APCL NF. Gelatin grafting can obviously enhance EC spreading and proliferation compared with the original material. Moreover, gelatin-grafted APCL NF readily orients ECs along the fibers whereas unmodified APCL NF does not. Immunostaining micrographs showed that ECs cultured on gelatin-grafted PCL NF were able to maintain the expression of three characteristic markers: platelet-endothelial cell adhesion molecule 1 (PECAM-1), intercellular adhesion molecule 1 (ICAM-1), and vascular cell adhesion molecule 1 (VCAM-1). The surface-modified PCL nanofibrous material is a potential candidate material in blood vessel tissue engineering.

  20. Phospholipid electrospun nanofibers: effect of solvents and co-axial processing on morphology and fiber diameter

    DEFF Research Database (Denmark)

    Jørgensen, Lars; Qvortrup, Klaus; Chronakis, Ioannis S.

    2015-01-01

    chloroform : dimethylformamide (CHCl3 : DMF, 3 : 2 v/v), isooctane, cyclohexane and limonene, producing phospholipid fibers with average diameters in the range of 2.57 +/- 0.59 mu m, similar to 3-8 mu m, similar to 4-5 mu m and 14.3 +/- 2.7 mu m, respectively. The diameter of asolectin electrospun fibers...

  1. Interfacial Properties of Lignin-Based Electrospun Nanofibers and Films Reinforced with Cellulose Nanocrystals

    Science.gov (United States)

    Mariko Ago; Joseph E. Jakes; Leena-Sisko Johansson; Sunkyu Park; Orlando J. Rojas

    2012-01-01

    Sub-100 nm resolution local thermal analysis, X-ray photoelectron spectroscopy (XPS), and water contact angle (WCA) measurements were used to relate surface polymer distribution with the composition of electrospun fiber mats and spin coated films obtained from aqueous dispersions of lignin, polyvinyl alcohol (PVA), and cellulose nanocrystal (CNC). Defect-free lignin/...

  2. Study on structure, mechanical property and cell cytocompatibility of electrospun collagen nanofibers crosslinked by common agents.

    Science.gov (United States)

    Luo, Xueshi; Guo, Zhenzhao; He, Ping; Chen, Tian; Li, Lihua; Ding, Shan; Li, Hong

    2018-01-29

    Collagen electrospun scaffolds properly reproduce the framework of the extracellular matrix (ECM) of tissues that are natural with the fibrous morphology of the protein by coupling large biomimetism of the biological material. However, traditional solvents employed for collagen electrospinning lead to poor mechanical attributes and bad hydro-stability. In this work, by N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride with N-hydroxysulfosuccinimide (EDC-NHS), glutaraldehyde (GTA) and genipin (GP) respectively, electrospun collagen fibers cross-linked, effectively stabilized the fiber morphology over 2 months and improved the mechanical properties in both dry and wet state, especially EDC-NHS with large ultimate tensile stress and ε b . The secondary structure of collagen structure still remained and had no obvious difference among various crosslinked samples according to FTIR. On the cell assessment, electrospun collagen fibers crosslinked by EDC-NHS, GTA and GP, were found to support cell adhesion, spreading and proliferation of MC3T3-E1. By contrast, GTA was more effective in preserving explicit fibrous morphology with a relatively lower cell viability both in FBS and BSA soaked mats. Interestingly, GP also had the similar cytocompatibility of MC3T3-E1 as EDC-NHS did. The study proved the feasibility of chemical crosslinker to electrospun collagen for biomedical application. Copyright © 2017. Published by Elsevier B.V.

  3. Electrospun carbon-tin oxide composite nanofibers for use as lithium ion battery anodes.

    Science.gov (United States)

    Bonino, Christopher A; Ji, Liwen; Lin, Zhan; Toprakci, Ozan; Zhang, Xiangwu; Khan, Saad A

    2011-07-01

    Composite carbon-tin oxide (C-SnO(2)) nanofibers are prepared by two methods and evaluated as anodes in lithium-ion battery half cells. Such an approach complements the long cycle life of carbon with the high lithium storage capacity of tin oxide. In addition, the high surface-to-volume ratio of the nanofibers improves the accessibility for lithium intercalation as compared to graphite-based anodes, while eliminating the need for binders or conductive additives. The composite nanofibrous anodes have first discharge capacities of 788 mAh g(-1) at 50 mA g(-1) current density, which are greater than pure carbon nanofiber anodes, as well as the theoretical capacity of graphite (372 mAh g(-1)), the traditional anode material. In the first protocol to fabricate the C-SnO(2) composites, tin sulfate is directly incorporated within polyacrylonitrile (PAN) nanofibers by electrospinning. During a thermal treatment the tin salt is converted to tin oxide and the polymer is carbonized, yielding carbon-SnO(2) nanofibers. In the second approach, we soak the nanofiber mats in tin sulfate solutions prior to the final thermal treatment, thereby loading the outer surfaces with SnO(2) nanoparticles and raising the tin content from 1.9 to 8.6 wt %. Energy-dispersive spectroscopy and X-ray diffraction analyses confirm the formation of conversion of tin sulfate to tin oxide. Furthermore, analysis with Raman spectroscopy reveals that the additional salt soak treatment from the second fabrication approach increases in the disorder of the carbon structure, as compared to the first approach. We also discuss the performance of our C-SnO(2) compared with its theoretical capacity and other nanofiber electrode composites previously reported in the literature.

  4. Application of electrospun CNx nanofibers as cathode in microfluidic fuel cell

    Science.gov (United States)

    Jindal, Amandeep; Basu, Suddhasatwa; Chauhan, Neha; Ukai, Tomofumi; Kumar, D. Sakthi; Samudhyatha, K. T.

    2017-02-01

    Carbon nitride (CNx) nanofibers is successfully utilised as cathode catalyst in microfluidic fuel cell (MFC) using electrospinning technique. The electrochemical measurement for CNx nanofibers as cathode catalyst in MFC is studied and compared with that of Pt and Au cathodes. Formic acid is employed as fuel, KMnO4 as oxidant and H2SO4 as supporting electrolyte. CNx nanofibers is shown to be not active towards formic acid oxidation and as a result, is tolerant to fuel crossover effect as compared to Pt and Au cathode. CNx nanofibers enable MFC to operate at a wider range of flow rates of fuel and oxidant as compared to Pt and Au conventionally used. MFC utilising CNx nanofibers gives higher power density of 3.43 mW cm-2 and the current density of 9.79 mAcm-2, as compared to that utilizes pure Au (2.72 mW cm-2, 6.04 mA cm-2) and Pt (3.09 mW cm-2, 6.18 mA cm-2) as anode.

  5. Evaluation of the Morphology and Osteogenic Potential of Titania-Based Electrospun Nanofibers

    Directory of Open Access Journals (Sweden)

    Xiaokun Wang

    2012-01-01

    Full Text Available Submicron-scale titania-based ceramic fibers with various compositions have been prepared by electrospinning. The as-prepared nanofibers were heat-treated at 700°C for 3 h to obtain pure inorganic fiber meshes. The results show that the diameter and morphology of the nanofibers are affected by starting polymer concentration and sol-gel composition. The titania and titania-silica nanofibers had the average diameter about 100–300 nm. The crystal phase varied from high-crystallized rutile-anatase mixed crystal to low-crystallized anatase with adding the silica addition. The morphology and crystal phase were evaluated by SEM and XRD. Bone-marrow-derived mesenchymal stem cells were seeded on titania-silica 50/50 fiber meshes. Cell number and early differentiation marker expressions were analyzed, and the results indicated osteogenic potential of the titania-silica 50/50 fiber meshes.

  6. Needleless electro-spun nanofibers used for filtration of small particles

    Directory of Open Access Journals (Sweden)

    Z. Zhang

    2013-08-01

    Full Text Available A composite aerosol filter media was prepared by depositing nanofibers on the non-woven fabrics substrate using needleless electrospinning technique. The polyvinyl alcohol nanofibers with mean diameters of ca. 100 nm were used as top layers. The filtration performance was evaluated by measuring the filtration of sodium chloride nanoparticles (75±20 nm through the filters. It was found that the filtration efficiency of the composite filter media for nanoparticles was increased along with the thickness of nanofibers mats which was controlled by the collection time during the electrospinning. The multi-layer arrangement for fabrication of the composite filter can achieve high filtration efficiency (up to 99.95% which was comparable to commercial high efficiency particulate air filters but with higher quality factor and less mass.

  7. Electrospun p-type CuO nanofibers for low-voltage field-effect transistors

    Science.gov (United States)

    Zhu, Huihui; Liu, Ao; Liu, Guoxia; Shan, Fukai

    2017-10-01

    One-dimensional metal-oxide nanofibers show great promise as the basis for nano-device platforms due to their large surface to volume ratio and unique electrical properties. Here, we represent the facile fabrication of p-type CuO nanofibers utilizing the electrospinning technique for field-effect transistors (FETs), which incorporate CuO nanofibers as a channel and high-κ Al2O3 as a dielectric layer. The FETs exhibit typical p-type characteristics with a high hole mobility of 3.5 cm2/Vs at a low operating voltage of 4 V, fast switching speed, and modulation of light emission over the external light-emitting diode.

  8. Electro-spun organic nanofibers elaboration process investigations using comparative analytical solutions.

    Science.gov (United States)

    Colantoni, A; Boubaker, K

    2014-01-30

    In this paper Enhanced Variational Iteration Method, EVIM is proposed, along with the BPES, for solving Bratu equation which appears in the particular elecotrospun nanofibers fabrication process framework. Elecotrospun organic nanofibers, with diameters less than 1/4 microns have been used in non-wovens and filtration industries for a broad range of filtration applications in the last decade. Electro-spinning process has been associated to Bratu equation through thermo-electro-hydrodynamics balance equations. Analytical solutions have been proposed, discussed and compared. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. Physical Properties of Polypeptide Electrospun Nanofiber Cell Culture Scaffolds on a Wettable Substrate

    OpenAIRE

    Cross, Michael C.; Khadka, Dhan B.; Haynie, Donald T.

    2012-01-01

    Physical properties of poly(L-ornithine) (PLO), a polycation, poly(L-glutamic acid4-co-L-tyrosine) (PLEY), a polyanion, and electrospun fibers made of these polymers have been determined and compared. The polymers adopted random coil-like conformations in aqueous feedstocks at neutral pH and in dehydrated cast films and fibers on glass, and the fibers comprised numerous counterions, according to spectral analysis. Adsorption of model proteins and se...

  10. Imaging, spectroscopic, mechanical and biocompatibility studies of electrospun Tecoflex® EG 80A nanofibers and composites thereof containing multiwalled carbon nanotubes

    Science.gov (United States)

    Macossay, Javier; Sheikh, Faheem A.; Cantu, Travis; Eubanks, Thomas M.; Salinas, M. Esther; Farhangi, Chakavak S.; Ahmad, Hassan; Hassan, M. Shamshi; Khil, Myung-seob; Maffi, Shivani K.; Kim, Hern; Bowlin, Gary l.

    2014-12-01

    The present study discusses the design, development, and characterization of electrospun Tecoflex® EG 80A class of polyurethane nanofibers and the incorporation of multiwalled carbon nanotubes (MWCNTs) to these materials. Scanning electron microscopy results confirmed the presence of polymer nanofibers, which showed a decrease in fiber diameter at 0.5% wt. and 1% wt. MWCNTs loadings, while transmission electron microscopy showed evidence of the MWCNTs embedded within the polymer matrix. The Fourier transform infrared spectroscopy and Raman spectroscopy were used to elucidate the polymer-MWCNTs intermolecular interactions, indicating that the C-N and N-H bonds in polyurethanes are responsible for the interactions with MWCNTs. Furthermore, tensile testing indicated an increase in the Young's modulus of the nanofibers as the MWCNTs concentration was increased. Finally, NIH 3T3 fibroblasts were seeded on the obtained nanofibers, demonstrating cell biocompatibility and proliferation. Therefore, the results indicate the successful formation of polyurethane nanofibers with enhanced mechanical properties, and demonstrate their biocompatibility, suggesting their potential application in biomedical areas.

  11. Water-Soluble Electrospun Nanofibers as a Method for On-Chip Reagent Storage

    Directory of Open Access Journals (Sweden)

    Minhui Dai

    2012-10-01

    Full Text Available This work demonstrates the ability to electrospin reagents into water-soluble nanofibers resulting in a stable on-chip enzyme storage format. Polyvinylpyrrolidone (PVP nanofibers were spun with incorporation of the enzyme horseradish peroxidase (HRP. Scanning electron microscopy (SEM of the spun nanofibers was used to confirm the non-woven structure which had an average diameter of 155 ± 34 nm. The HRP containing fibers were tested for their change in activity following electrospinning and during storage. A colorimetric assay was used to characterize the activity of HRP by reaction with the nanofiber mats in a microtiter plate and monitoring the change in absorption over time. Immediately following electrospinning, the activity peak for the HRP decreased by approximately 20%. After a storage study over 280 days, 40% of the activity remained. In addition to activity, the fibers were observed to solubilize in the microfluidic chamber. The chromogenic 3,3′,5,5′-tetramethylbenzidine solution reacted immediately with the fibers as they passed through a microfluidic channel. The ability to store enzymes and other reagents on-chip in a rapidly dispersible format could reduce the assay steps required of an operator to perform.

  12. A continuous process to align electrospun nanofibers into parallel and crossed arrays

    Energy Technology Data Exchange (ETDEWEB)

    Laudenslager, Michael J.; Sigmund, Wolfgang M., E-mail: wsigm@mse.ufl.edu [University of Florida, Department of Materials Science and Engineering (United States)

    2013-04-15

    Electrical, optical, and mechanical properties of nanofibers are strongly affected by their orientation. Electrospinning is a nanofiber processing technique that typically produces nonwoven meshes of randomly oriented fibers. While several alignment techniques exist, they are only able to produce either a very thin layer of aligned fibers or larger quantities of fibers with less control over their alignment and orientation. The technique presented herein fills the gap between these two methods allowing one to produce thick meshes of highly oriented nanofibers. In addition, this technique is not limited to collection of fibers along a single axis. Modifications to the basic setup allow collection of crossed fibers without stopping and repositioning the apparatus. The technique works for a range of fiber sizes. In this study, fiber diameters ranged from 100 nm to 1 micron. This allows a few fibers at a time to rapidly deposit in alternating directions creating an almost woven structure. These aligned nanofibers have the potential to improve the performance of energy storage and thermoelectric devices and hold great promise for directed cell growth applications.

  13. Biocompatible core–shell electrospun nanofibers as potential application for chemotherapy against ovary cancer

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Eryun; Fan, Yingmei [College of Material Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Sun, Zhiyao [Key Laboratory of Polymer Functional Materials, Heilongjiang University, Harbin 150080 (China); Gao, Jianwei [College of Food and Biological Engineering, Qiqihar University, Qiqihar 161006 (China); Hao, Xiaoyuan [College of Material Science and Engineering, Qiqihar University, Qiqihar 161006 (China); Pei, Shichun [College of Food and Biological Engineering, Qiqihar University, Qiqihar 161006 (China); Wang, Cheng, E-mail: wangc_93@163.com [Key Laboratory of Polymer Functional Materials, Heilongjiang University, Harbin 150080 (China); Sun, Liguo [Key Laboratory of Polymer Functional Materials, Heilongjiang University, Harbin 150080 (China); Zhang, Deqing, E-mail: zhdqing@163.com [College of Material Science and Engineering, Qiqihar University, Qiqihar 161006 (China)

    2014-08-01

    Polyvinyl alcohol/chitosan (PVA/CS) core–shell nanofibers are successfully fabricated by a simple coaxial electrospinning method, in which PVA forms the core layer and CS forms the shell layer. With the change of the feed ratio between PVA and CS, the surface morphology and the microstructures of the nanofibers are largely changed. The as-prepared core–shell fibers can be used as a carrier for doxorubicin (DOX) delivery. FT-IR analysis demonstrates that hydrogen bond between CS and PVA chains forms. The results of in vitro cytotoxicity test indicate that the core–shell fibers are completely biocompatible and the free DOX shows higher cytotoxicity than the DOX loaded nanofibers. The standing PVA/CS core–shell fibers remarkably promote the attachment, proliferation and spreading of human ovary cancer cells (SKOV3). Via observing by confocal laser scanning microscopy (CLSM), the DOX released from the fibers can be delivered into SKOV3 cell nucleus, which is significant for the future tumor therapy. And, the as-prepared fibers exhibit controlled release for loaded DOX via adjusting the feed ratio between PVA and CS, and the DOX loaded nanofibers are quite effective in prohibiting the SKOV3 ovary cells attachment and proliferation, which are potential for chemotherapy of ovary cancer. - Highlights: • PVA/CS core–shell fibers were prepared by coaxial electrospinning. • The core–shell fibers were completely biocompatible. • In vitro release experiments indicated that the drug release rate was controllable. • The free DOX showed higher cytotoxicity than the DOX loaded nanofibers. • DOX loaded fibers were potential for chemotherapy of ovary cancer.

  14. Emerging investigator series: development and application of polymeric electrospun nanofiber mats as equilibrium-passive sampler media for organic compounds.

    Science.gov (United States)

    Qian, Jiajie; Jennings, Brandon; Cwiertny, David M; Martinez, Andres

    2017-11-15

    We fabricated a suite of polymeric electrospun nanofiber mats (ENMs) and investigated their performance as next-generation passive sampler media for environmental monitoring of organic compounds. Electrospinning of common polymers [e.g., polyacrylonitrile (PAN), polymethyl methacrylate (PMMA), and polystyrene (PS), among others] yielded ENMs with reproducible control of nanofiber diameters (from 50 to 340 nm). The ENM performance was investigated initially with model hydrophilic (aniline and nitrobenzene) and hydrophobic (selected PCB congeners and dioxin) compounds, generally revealing fast chemical uptake into all of these ENMs, which was well described by a one compartment, first-order kinetic model. Typical times to reach 90% equilibrium (t90%) were ≤7 days under mixing conditions for all the ENMs and equilibrium timescales suggest that ENMs may be used in the field as an equilibrium-passive sampler, at least for our model compounds. Equilibrium partitioning coefficients (KENM-W, L kg-1) averaged 2 and 4.7 log units for the hydrophilic and hydrophobic analytes, respectively. PAN, PMMA and PS were prioritized for additional studies because they exhibited not only the greatest capacity for simultaneous uptake of the entire model suite (log KENM-W ∼1.5-6.2), but also fast uptake. For these optimized ENMs, the rates of uptake into PAN and PMMA were limited by aqueous phase diffusion to the nanofiber surface, and the rate-determining step for PS was analyte specific. Sorption isotherms also revealed that the environmental application of these optimized ENMs would occur within the linear uptake regime. We examined the ENM performance for the measurement of pore water concentrations from spiked soil and freshwater sediments. Soil and sediment studies not only yielded reproducible pore water concentrations and comparable values to other passive sampler materials, but also provided practical insights into ENM stability and fouling in such systems. Furthermore

  15. Drug loaded homogeneous electrospun PCL/gelatin hybrid nanofiber structures for anti-infective tissue regeneration membranes.

    Science.gov (United States)

    Xue, Jiajia; He, Min; Liu, Hao; Niu, Yuzhao; Crawford, Aileen; Coates, Phil D; Chen, Dafu; Shi, Rui; Zhang, Liqun

    2014-11-01

    Infection is the major reason for guided tissue regeneration/guided bone regeneration (GTR/GBR) membrane failure in clinical application. In this work, we developed GTR/GBR membranes with localized drug delivery function to prevent infection by electrospinning of poly(ε-caprolactone) (PCL) and gelatin blended with metronidazole (MNA). Acetic acid (HAc) was introduced to improve the miscibility of PCL and gelatin to fabricate homogeneous hybrid nanofiber membranes. The effects of the addition of HAc and the MNA content (0, 1, 5, 10, 20, 30, and 40 wt.% of polymer) on the properties of the membranes were investigated. The membranes showed good mechanical properties, appropriate biodegradation rate and barrier function. The controlled and sustained release of MNA from the membranes significantly prevented the colonization of anaerobic bacteria. Cells could adhere to and proliferate on the membranes without cytotoxicity until the MNA content reached 30%. Subcutaneous implantation in rabbits for 8 months demonstrated that MNA-loaded membranes evoked a less severe inflammatory response depending on the dose of MNA than bare membranes. The biodegradation time of the membranes was appropriate for tissue regeneration. These results indicated the potential for using MNA-loaded PCL/gelatin electrospun membranes as anti-infective GTR/GBR membranes to optimize clinical application of GTR/GBR strategies. Copyright © 2014 Elsevier Ltd. All rights reserved.

  16. Facile Synthesis of Indium Sulfide/Flexible Electrospun Carbon Nanofiber for Enhanced Photocatalytic Efficiency and Its Application

    Directory of Open Access Journals (Sweden)

    Liu Han

    2017-01-01

    Full Text Available Heterojunction system has been proved as one of the best architectures for photocatalyst owing to extending specific surface area, expanding spectral response range, and increasing photoinduced charges generation, separation, and transmission, which can provide better light absorption range and higher reaction site. In this paper, Indium Sulfide/Flexible Electrospun Carbon Nanofiber (In2S3/CNF heterogeneous systems were synthesized by a facile one-pot hydrothermal method. The results from characterizations of SEM, TEM, XRD, Raman, and UV-visible diffuse reflectance spectroscopy displayed that flower-like In2S3 was deposited on the hair-like CNF template, forming a one-dimensional nanofibrous network heterojunction photocatalyst. And the newly prepared In2S3/CNF photocatalysts exhibit greatly enhanced photocatalytic activity compared to pure In2S3. In addition, the formation mechanism of the one-dimensional heterojunction In2S3/CNF photocatalyst is discussed and a promising approach to degrade Rhodamine B (RB in the photocatalytic process is processed.

  17. Improved supercapacitor performance of MnO2-electrospun carbon nanofibers electrodes by mT magnetic field

    Science.gov (United States)

    Zeng, Zheng; Liu, Yiyang; Zhang, Wendi; Chevva, Harish; Wei, Jianjun

    2017-08-01

    This work reports on a finding of mT magnetic field induced energy storage enhancement of MnO2-based supercapacitance electrodes (magneto-supercapacitor). Electrodes with MnO2 electrochemically deposited at electrospun carbon nanofibers (ECNFs) film are studied by cyclic voltammetry (CV), galvanostatic charge/discharge, electrochemical impedance spectroscopy (EIS), and life cycle stability tests in the presence/absence of milli-Tesla (mT) magnetic fields derived by Helmholtz coils. In the presence of a 1.34 mT magnetic field, MnO2/ECNFs shows a magneto-enhanced capacitance of 141.7 F g-1 vs. 119.2 F g-1 (∼19% increase) with absence of magnetic field at a voltage sweeping rate of 5 mV s-1. The mechanism of the magneto-supercapacitance is discussed and found that the magnetic susceptibility of the MnO2 significantly improves the electron transfer of a pseudo-redox reaction of Mn(IV)/Mn(III) at the electrode, along with the magnetic field induced impedance effect, which may greatly enhance the interface charge density, facilitate electrolyte transportation, and improve the efficiency of cation intercalation/de-intercalation of the pseudocapacitor under mT-magnetic field exposure, resulting in enhancement of energy storage capacitance and longer charge/discharge time of the MnO2/ECNFs electrode without sacrificing its life cycle stability.

  18. Solid-State Lithium Conductors for Lithium Metal Batteries Based on Electrospun Nanofiber/Plastic Crystal Composites.

    Science.gov (United States)

    Zhou, Yundong; Wang, Xiaoen; Zhu, Haijin; Yoshizawa-Fujita, Masahiro; Miyachi, Yukari; Armand, Michel; Forsyth, Maria; Greene, George W; Pringle, Jennifer M; Howlett, Patrick C

    2017-08-10

    Organic ionic plastic crystals (OIPCs) are a class of solid-state electrolytes with good thermal stability, non-flammability, non-volatility, and good electrochemical stability. When prepared in a composite with electrospun polyvinylidene fluoride (PVdF) nanofibers, a 1:1 mixture of the OIPC N-ethyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide ([C2 mpyr][FSI]) and lithium bis(fluorosulfonyl)imide (LiFSI) produced a free-standing, robust solid-state electrolyte. These high-concentration Li-containing electrolyte membranes had a transference number of 0.37(±0.02) and supported stable lithium symmetric-cell cycling at a current density of 0.13 mA cm-2 . The effect of incorporating PVdF in the Li-containing plastic crystal was investigated for different ratios of PVdF and [Li][FSI]/[C2 mpyr][FSI]. In addition, Li|LiNi1/3 Co1/3 Mn1/3 O2 cells were prepared and cycled at ambient temperature and displayed a good rate performance and stability. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Electrospun gelatin nanofibers loaded with vitamins A and E as antibacterial wound dressing materials

    OpenAIRE

    Williams, G. R.; Li, H.; Wang, M.; Wu, J.; Sun, X.; Lv, Y.; Zhu, L. M.

    2016-01-01

    Vitamin A palmitate and vitamin E TPGS, common derivatives of the unstable vitamins A and E, were successfully incorporated into biodegradable gelatin nanofibers via electrospinning. Electron microscopy showed that smooth cylindrical fibers were produced, albeit with a small amount of beading visible for the vitamin-loaded systems. The diameters of the fibers decrease with the addition of vitamins. The presence of the vitamins in the fibers was confirmed by IR spectroscopy, and X-ray diffract...

  20. The influence of zirconia precursor/binding polymer mass ratio in the intermediate electrospun composite fibers on the phase transformation of final zirconia nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Rodaev, Vyacheslav V.; Zhigachev, Andrey O.; Korenkov, Viktor V.; Golovin, Yuri I. [Institute for Nanotechnology and Nanomaterials, Tambov State University, Internatsionalnaya Str. 33, 392000, Tambov (Russian Federation)

    2016-09-15

    Nanofibrous zirconia was fabricated by calcination of electrospun zirconium oxychloride/polyethylene oxide (PEO) composite fibers with different mass fraction of the components. ZrO{sub 2} nanofibers were characterized by scanning electron microscopy (SEM), nitrogen adsorption at 77 K, and X-ray diffractometry (XRD). It was revealed that increase in ZrOCl{sub 2}/PEO mass ratio above the threshold value significantly decreases tetragonal phase (t-ZrO{sub 2}) content and increases monoclinic phase (m-ZrO{sub 2}) content in final ceramic nanofibers. Distinct t-ZrO{sub 2} → m-ZrO{sub 2} transformation takes place when average ZrO{sub 2} grain size approaches to 30 nm. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Macrophage repolarization using emu oil-based electrospun nanofibers: possible application in regenerative medicine.

    Science.gov (United States)

    Zamani, Reza; Pilehvar-Soltanahmadi, Younes; Alizadeh, Effat; Zarghami, Nosratollah

    2017-08-23

    In the regenerative medicine therapies, the availability of engineered scaffolds that modulate inflammatory states is highly required. The aim of this study was to evaluate the efficiency of electrospun nanofibrous scaffolds containing natural substances with anti-inflammatory properties such as Emu oil (EO) to control inflammation and re-polarization of macrophages toward M2 anti-inflammatory phonotype. For this purpose, bead free and smooth EO-blended PCL/PEG electrospun nanofibrous mats were successfully fabricated and characterized using FE-SEM, FTIR, and Universal Testing Machine. GC/MS findings of pure EO revealed the fatty acids composition. MTT results showed that macrophage viability on EO-PCL/PEG nanofibres was higher than on PCL/PEG nanofibres and control (p ≤ .05). Additionally, the presence of EO into nanofibres was found to influence on macrophage morphologies, using FE-SEM. qPCR results showed a reduction in iNOS-2 and an increase in Arg-1 levels of macrophages seeded on EO-PCL/PEG nanofibres, indicating the successfully polarization of the macrophages to M2 phenotype. The change in macrophage phenotype on EO-based nanofibres could suppress the inflammation in LPS/IFN-γ stimulated macrophages as evidenced by a major reduction in pro-inflammatory cytokine levels TNF-α, IL-1β, and IL-6. Conclusively, the results demonstrated that EO-based nanofibres efficiently modulated RAW264.7 macrophage polarity toward an anti-inflammatory M2 phenotype.

  2. Design of Boron Nitride/Gelatin Electrospun Nanofibers for Bone Tissue Engineering.

    Science.gov (United States)

    Nagarajan, Sakthivel; Belaid, Habib; Pochat-Bohatier, Céline; Teyssier, Catherine; Iatsunskyi, Igor; Coy, Emerson; Balme, Sébastien; Cornu, David; Miele, Philippe; Kalkura, Narayana S; Cavaillès, Vincent; Bechelany, Mikhael

    2017-10-04

    Gelatin is a biodegradable biopolymer obtained by collagen denaturation, which shows poor mechanical properties. Hence, improving its mechanical properties is very essential toward the fabrication of efficient nontoxic material for biomedical applications. For this aim, various methods are employed using external fillers such as ceramics or bioglass. In this report, we introduce boron nitride (BN)-reinforced gelatin as a new class of two-dimensional biocompatible nanomaterials. The effect of the nanofiller on the mechanical behavior is analyzed. BN is efficiently exfoliated using the biopolymer gelatin as shown through Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). The exfoliated BN reinforces gelatin electrospun fibers, which results in an increase in the Young's modulus. The Electrospun Mats (ESM) are stable after the glutaraldehyde cross-linking, and the fibrous morphology is preserved. The cross-linked gelatin/BN ESM is highly bioactive in forming bonelike hydroxyapatite as shown by scanning electron microscopy. Due to their enhanced mineralization ability, the cross-linked ESM have been tested on human bone cells (HOS osteosarcoma cell line). The cell attachment, proliferation, and biocompatibility results show that the ESM are nontoxic and biodegradable. The analysis of osteoblast gene expression and the measurement of alkaline phosphatase activity confirm that these materials are suitable for bone tissue engineering.

  3. Functionalized polymer-iron oxide hybrid nanofibers: Electrospun filtration devices for metal oxyanion removal.

    Science.gov (United States)

    Peter, Katherine T; Johns, Adam J; Myung, Nosang V; Cwiertny, David M

    2017-06-15

    Via a single-pot electrospinning synthesis, we developed a functionalized polymer-metal oxide nanofiber filter for point of use (POU) water treatment of metal oxyanions (e.g., arsenate and chromate). Polyacrylonitrile (PAN) functionalization was accomplished by inclusion of surface-active, quaternary ammonium salts (QAS) [cetyltrimethylammonium bromide (CTAB) or tetrabutylammonium bromide (TBAB)] that provide strong base ion exchange sites. Embedded iron oxide [ferrihydrite (Fh)] nanoparticles were used for their established role as metal sorbents. We examined the influence of QAS and Fh loading on composite properties, including nanofiber morphology, surface area, surface chemical composition, and the accessibility of embedded nanoparticles to solution. Composite performance was then evaluated using kinetic, isotherm, and pH-edge sorption experiments with arsenate and chromate, and benchmarked to unmodified PAN nanofibers and freely dispersed Fh nanoparticles. We also assessed the long-term stability of QAS in the composite matrix. For composites containing QAS or Fh nanoparticles, increasing QAS/Fh nanoparticle loading generally yielded increasing metal oxyanion uptake. The optimized composite (PAN 7 wt%, Fh 3 wt%, TBAB 1 wt%) exhibited two distinct sites for simultaneous, non-competitive metal binding (i.e., iron oxide sites for arsenate removal via sorption and well-retained QAS sites for chromate removal via ion exchange). Moreover, surface-segregating QAS enriched Fh abundance at the nanofiber surface, allowing immobilized nanoparticles to exhibit reactivity comparable to that of unsupported (i.e., suspended or freely dispersed) nanoparticles. To simulate POU application, the optimized composite was tested in a dead-end, flow-through filtration system for arsenate and chromate removal at environmentally relevant concentrations (e.g., μg/L) in both idealized and simulated tap water matrices. Performance trends indicate that dual mechanisms for uptake are

  4. Electrospun carbon-cobalt composite nanofiber as an anode material for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Wang Long; Yu Yan; Chen Pice [Laboratory for Advanced Functional Materials and Devices, Department of Materials Science and Engineering, University of Science and Technology of China, Anhui Hefei 230026 (China); Chen Chunhua [Laboratory for Advanced Functional Materials and Devices, Department of Materials Science and Engineering, University of Science and Technology of China, Anhui Hefei 230026 (China)], E-mail: cchchen@ustc.edu.cn

    2008-03-15

    Carbon-cobalt (C/Co) composite nanofibers with diameters from 100 to 300 nm were prepared by electrospinning and subsequent heat treatment. They were characterized by X-ray diffraction, scanning electron microscopy, galvanostatic cell cycling and impedance spectroscopy. As a lithium storage material, these fibers exhibit excellent electrochemical properties with high reversible capacity (>750 mA h g{sup -1}) and good rate capability (578 mA h g{sup -1} at 1 C rate). These composite fibers are a promising anode material for high-power Li-ion batteries.

  5. Study of Hydrophilic Electrospun Nanofiber Membranes for Filtration of Micro and Nanosize Suspended Particles

    Directory of Open Access Journals (Sweden)

    Nurxat Nuraje

    2013-11-01

    Full Text Available Polymeric nanofiber membranes of polyvinyl chloride (PVC blended with polyvinylpyrrolidone (PVP were fabricated using an electrospinning process at different conditions and used for the filtration of three different liquid suspensions to determine the efficiency of the filter membranes. The three liquid suspensions included lake water, abrasive particles from a water jet cutter, and suspended magnetite nanoparticles. The major goal of this research work was to create highly hydrophilic nanofiber membranes and utilize them to filter the suspended liquids at an optimal level of purification (i.e., drinkable level. In order to overcome the fouling/biofouling/blocking problems of the membrane, a coagulation process, which enhances the membrane’s efficiency for removing colloidal particles, was used as a pre-treatment process. Two chemical agents, Tanfloc (organic and Alum (inorganic, were chosen for the flocculation/coagulation process. The removal efficiency of the suspended particles in the liquids was measured in terms of turbidity, pH, and total dissolved solids (TDS. It was observed that the coagulation/filtration experiments were more efficient at removing turbidity, compared to the direct filtration process performed without any coagulation and filter media.

  6. Electrospun ZnO/Bi2O3 Nanofibers with Enhanced Photocatalytic Activity

    Directory of Open Access Journals (Sweden)

    Yingying Yang

    2014-01-01

    Full Text Available ZnO/Bi2O3 nanofibers were synthesized by a simple electrospinning method and both the UV and visible light responsive photocatalytic properties were studied by the decolorization of RhB dye. Thermogravimetric analysis/differential thermal analysis (TGA-DTA, X-ray diffraction (XRD, scanning electron microscope (SEM, and UV-vis diffuse reflectance spectra (DRS were employed to study the structure, morphology, and optical properties of the ZnO/Bi2O3 nanofibers, respectively. The relationship between the ZnO/Bi2O3 ratio and photocatalytic activity was also studied, and the composite with a molar ratio of 23 : 1 demonstrated the best activity under both excitations. The photocatalytic mechanisms for the composite fibers can be described as the direct photocatalysis under UV excitation and photosensitation for visible light irradiation. The enhanced photocatalytic activities can be ascribed to the effective electron-hole pairs separation that leads to the promoted photocatalytic efficiency.

  7. Characterization of carbon nanofiber mats produced from electrospun lignin-g-polyacrylonitrile copolymer.

    Science.gov (United States)

    Youe, Won-Jae; Lee, Soo-Min; Lee, Sung-Suk; Lee, Seung-Hwan; Kim, Yong Sik

    2016-01-01

    The graft copolymerization of acrylonitrile (AN) onto methanol-soluble kraft lignin (ML) was achieved through a two-step process in which AN was first polymerized with an α,α'-azobisisobutyronitrile initiator, followed by radical coupling with activated ML. A carbon nanofiber material was obtained by electrospinning a solution of this copolymer in N,N-dimethylformamide, then subjecting it to a heat treatment including thermostabilization at 250°C and subsequent carbonization at 600-1400°C. Increasing the carbonization temperature was found to increase the carbon content of the resulting carbon nanofibers from 70.5 to 97.1%, which had the effect of increasing their tensile strength from 35.2 to 89.4 MPa, their crystallite size from 13.2 to 19.1 nm, and their electrical conductivity from ∼0 to 21.3 Scm(-1). The morphology of the mats, in terms of whether they experienced beading or not, was found to be dependent on the concentration of the initial electrospinning solution. From these results, it is proposed that these mats could provide the basis for a new class of carbon fiber material. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Surface Functional Poly(lactic Acid Electrospun Nanofibers for Biosensor Applications

    Directory of Open Access Journals (Sweden)

    Edurne González

    2016-01-01

    Full Text Available In this work, biotin surface functionalized hydrophilic non-water-soluble biocompatible poly(lactic acid (PLA nanofibers are created for their potential use as biosensors. Varying concentrations of biotin (up to 18 weight total percent (wt % were incorporated into PLA fibers together with poly(lactic acid-block-poly(ethylene glycol (PLA-b-PEG block polymers. While biotin provided surface functionalization, PLA-b-PEG provided hydrophilicity to the final fibers. Morphology and surface-available biotin of the final fibers were studied by Field Emission Scanning Electron Microscopy (FESEM and competitive colorimetric assays. The incorporation of PLA-b-PEG block copolymers not only decreased fiber diameters but also dramatically increased the amount of biotin available at the fiber surface able to bind avidin. Finally, fiber water stability tests revealed that both biotin and PLA-b-PEG, migrated to the aqueous phase after relatively extended periods of water exposure. The functional hydrophilic nanofiber created in this work shows a potential application as a biosensor for point-of-care diagnostics.

  9. A Microfluidic Chip Integrated with Hyaluronic Acid-Functionalized Electrospun Chitosan Nanofibers for Specific Capture and Nondestructive Release of CD44-Overexpressing Circulating Tumor Cells.

    Science.gov (United States)

    Wang, Mengyuan; Xiao, Yunchao; Lin, Lizhou; Zhu, Xiaoyue; Du, Lianfang; Shi, Xiangyang

    2018-02-07

    Detection of circulating tumor cells (CTCs) in peripheral blood is of paramount significance for early-stage cancer diagnosis, estimation of cancer development, and individualized cancer therapy. Herein, we report the development of hyaluronic acid (HA)-functionalized electrospun chitosan nanofiber (CNF)-integrated microfludic platform for highly specific capture and nondestructive release of CTCs. First, electrospun CNFs were formed and modified with zwitterion of carboxyl betaine acrylamide (CBAA) via Michael addition reaction and then targeted ligand HA through a disulfide bond. We show that the formed nanofibers still maintain the smooth fibrous morphology after sequential surface modifications, have a good hemocompatibility, and exhibit an excellent antifouling property due to the CBAA modification. After embedded within a microfluidic chip, the fibrous mat can capture cancer cells (A549, a human lung cancer cell line) with an efficiency of 91% at a flow rate of 1.0 mL/h. Additionally, intact release of cancer cells is able to be achieved after treatment with glutathione for 40 min to have a release efficiency of 90%. Clinical applications show that 9 of 10 non-small-cell lung cancer patients and 5 of 5 breast cancer patients are diagnosed to have CTCs (1 to 18 CTCs per mL of blood). Our results suggest that the developed microfluidic system integrated with functionalized CNF mats may be employed for effective CTCs capture for clinical diagnosis of cancer.

  10. Fabricating and Characterizing Physical Properties of Electrospun Polypeptide-based Nanofibers

    Science.gov (United States)

    Khadka, Dhan Bahadur

    pH values. Variations in fiber morphology, elemental composition and stability have been studied by microscopy and energy-dispersive X-ray spectroscopy (EDX), following the treatment of samples at different pH values in the 2-12 range. Fiber stability has been interpreted with reference to the pH dependence of the UV absorbance and fluorescence of PLEY chains in solution. The data show that fiber stability is crucially dependent on the extent of side chain ionization, even after crosslinking. Self-organization kinetics of electrospun PLO and PLEY fibers during solvent annealing has been studied. After being crosslinked in situ , fibers were annealed in water at 22 °C. Analysis by Fourier transform infrared spectroscopy (FTIR) has revealed that annealing involved fiber restructuring with an overall time constant of 29 min for PLO and 63 min for PLEY, and that changes in the distribution of polymer conformations occurred during the first 13 min of annealing. There was a substantial decrease in the amount of Na+ bound to PLEY fibers during annealing. Kinetic modeling has indicated that two parallel pathways better account for the annealing trajectory than a single pathway with multiple transition states. Taken together, the results will advance the rational design of polypeptides for peptide-based materials, especially materials prepared by electrospinning. It is believed that this research will increase basic knowledge of polymer electrospinning and advance the development of electrospun materials, especially in medicine and biotechnology. The study has yielded two advances on previous work in the area: avoidance of an animal source of peptides and avoidance of inorganic solvent. The present results thus advance the growing field of peptide-based materials. Non-woven electrospun fiber mats made of polypeptides are increasingly considered attractive for basic research and technology development in biotechnology, medicine and other areas. (Abstract shortened by UMI.)

  11. Anisotropically Enhanced Nonlinear Optical Properties of Ensembles of Gold Nanorods Electrospun in Polymer Nanofiber Film.

    Science.gov (United States)

    Zhang, Hang; Hu, Zhongliang; Ma, Zhijun; Gecevičius, Mindaugas; Dong, Guoping; Zhou, Shifeng; Qiu, Jianrong

    2016-01-27

    Polymeric nanofibers containing gold nanorods (GNRs) are aligned in a uniform orientation through electrospinning. The dispersive and absorptive parts of the third-order optical nonlinear optical refractive index of the composite film measured by polarization dependent z-scan method are demonstrated to be anisotropically enhanced. Anisotropic optical response of the aligned GNRs and its connection with the ultrafast electron dynamics are discussed in light of the results of resonant femtosecond pump-probe experiments. The significant appearance of anisotropic nonlinear optical properties of ensembles of GNRs is attributed to the sensitive excitation of longitudinal surface plasmon resonance (LSPR) of highly aligned GNRs. For the macroscopic applications of ensembles of GNRs, such as passive mode-locking and all-optical switching, the experimental results demonstrate that the alignment of GNRs through electrospinning should be very high efficient, and economic.

  12. Electrospun MnCo2O4 nanofibers for efficient hydrogen evolution reaction

    Science.gov (United States)

    Wu, Cong; Li, Chuang; Yang, Boyu; Zhou, Siyuan; Shi, Dingcong; Wang, Yanbo; Yang, Guocheng; He, Jin; Shan, Yuping

    2016-09-01

    MnCo2O4 nanofibers (MCNFs) were successfully synthesized by electrospinning followed by a calcination process under mild conditions. The structural and morphological characterizations of MCNFs were performed by x-ray powder diffraction (XRD), thermogravimetric analysis (TGA), Raman spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical method was used to measure the electrocatalytic hydrogen evolution reaction (HER) properties of MCNFs. Electrochemical studies show that the developed MCNFs possess excellent electroactivity towards HER with low hydrogen-evolution overpotential and a small Tafel slope. In addition, electrospinning can promote the materials into nano-sized architectures with large surface area, which can effectively enhance the electrocatalytic HER properties of MCNFs.

  13. Electrospun graphene decorated MnCo2O4 composite nanofibers for glucose biosensing.

    Science.gov (United States)

    Zhang, Yuting; Liu, Shuai; Li, Yu; Deng, Dongmei; Si, Xiaojing; Ding, Yaping; He, Haibo; Luo, Liqiang; Wang, Zhenxin

    2015-04-15

    Graphene decorated MnCo2O4 composite nanofibers (GMCFs) were synthesized by electrospinning and subsequent calcination in an Ar atmosphere. The structural and morphological characterizations of GMCFs were performed using X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, energy-dispersive spectroscopy, scanning electron microscopy and transmission electron microscopy. The synthesized GMCFs combine the catalytic activity of spinel-type MnCo2O4 with the remarkable conductivity of graphene. In addition, electrospinning can process MnCo2O4 materials into nanosized architectures with large surface area to prevent magnetic nanoparticles from aggregating. The obtained GMCFs were applied as a novel platform for glucose biosensing. Electrochemical studies show that the developed biosensor exhibits excellent electrocatalytic activity towards glucose oxidation over a wide linear range of 0.005-800µM with a low detection limit of 0.001µM. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Dehydration of bacteriophages in electrospun nanofibers: effect of excipients in polymeric solutions

    Science.gov (United States)

    Koo, Charmaine K. W.; Senecal, Kris; Senecal, Andre; Nugen, Sam R.

    2016-12-01

    Bacteriophages are viruses capable of infecting and lysing target bacterial cells; as such they have potential applications in agriculture for decontamination of foods, food contact surfaces and food rinse water. Although bacteriophages can retain infectivity long-term using lyophilized storage, the process of freeze-drying can be time consuming and expensive. In this study, electrospinning was used for dehydrating bacteriophages in polyvinylpyrrolidone polymer solutions with addition of excipients (sodium chloride, magnesium sulfate, Tris-HCl, sucrose) in deionized water. The high voltage dehydration reduced the infectivity of bacteriophages following electrospinning, with the damaging effect abated with addition of storage media (SM) buffer and sucrose. SM buffer and sucrose also provided the most protection over extended storage (8 weeks; 20 °C 1% relative humidity) by mitigating environmental effects on the dried bacteriophages. Magnesium sulfate however provided the least protection due to coagulation effects of the ion, which can disrupt the native conformation of the bacteriophage protein coat. Storage temperatures (20 °C, 4 °C and -20 °C 1% relative humidity) had a minimal effect while relative humidity had substantial effect on the infectivity of bacteriophages. Nanofibers stored in higher relative humidity (33% and 75%) underwent considerable damage due to extensive water absorption and disruption of the fibers. Overall, following storage of nanofiber mats for eight weeks at ambient temperatures, high infective phage concentrations (106-107 PFU ml-1) were retained. Therefore, this study provided valuable insights on preservation and dehydration of bacteriophages by electrospinning in comparison to freeze drying and liquid storage, and the influence of excipients on the viability of bacteriophages.

  15. Electrospun Hydroxyapatite-Containing Chitosan Nanofibers Crosslinked with Genipin for Bone Tissue Engineering

    Science.gov (United States)

    Frohbergh, Michael E.; Katsman, Anna; Botta, Gregory P.; Lazarovici, Phillip; Schauer, Caroline L.; Wegst, Ulrike G. K.; Lelkes, Peter I.

    2012-01-01

    Reconstruction of large bone defects remains problematic in orthopedic and craniofacial clinical practice. Autografts are limited in supply and are associated with donor site morbidity while other materials show poor integration with the host’s own bone. This lack of integration is often due to the absence of periosteum, the outer layer of bone that contains osteoprogenitor cells and is critical for the growth and remodeling of bone tissue. In this study we developed a one-step platform to electrospin nanofibrous scaffolds from chitosan, which also contain hydroxyapatite nanoparticles and are crosslinked with genipin. We hypothesized that the resulting composite scaffolds represent a microenvironment that emulates the physical, mineralized structure and mechanical properties of non-weight bearing bone extracellular matrix while promoting osteoblast differentiation and maturation similar to the periosteum. The ultrastructure and physicochemical properties of the scaffolds were studied using scanning electron microscopy and spectroscopic techniques. The average fiber diameters of the electrospun scaffolds were 227±154 nm as spun, and increased to 335±119 nm after crosslinking with genipin. Analysis by X-ray diffraction, Fourier transformed infrared spectroscopy and energy dispersive spectroscopy confirmed the presence of characteristic features of hydroxyapatite in the composite chitosan fibers. The Young’s modulus of the composite fibrous scaffolds was 142±13 MPa, which is similar to that of the natural periosteum. Both pure chitosan scaffolds and composite hydroxyapatite-containing chitosan scaffolds supported adhesion, proliferation and osteogenic differentiation of mouse 7F2 osteoblast-like cells. Expression and enzymatic activity of alkaline phosphatase, an early osteogenic marker, were higher in cells cultured on the composite scaffolds as compared to pure chitosan scaffolds, reaching a significant, 2.4 fold, difference by day 14 (phydroxyapatite

  16. Effect of calcination temperature on formaldehyde oxidation performance of Pt/TiO2 nanofiber composite at room temperature

    Science.gov (United States)

    Xu, Feiyan; Le, Yao; Cheng, Bei; Jiang, Chuanjia

    2017-12-01

    Catalytic oxidation at room temperature over well-designed catalysts is an environmentally friendly method for the abatement of indoor formaldehyde (HCHO) pollution. Herein, nanocomposites of platinum (Pt) and titanium dioxide (TiO2) nanofibers with various phase compositions were prepared by calcining the electrospun TiO2 precursors at different temperatures and subsequently depositing Pt nanoparticles (NPs) on the TiO2 through a NaBH4-reduction process. The phase compositions and structures of Pt/TiO2 can be easily controlled by varying the calcination temperature. The Pt/TiO2 nanocomposites showed a phase-dependent activity towards the catalytic HCHO oxidation. Pt/TiO2 containing pure rutile phase showed enhanced activity with a turnover frequency (TOF) of 16.6 min-1 (for a calcination temperature of 800 °C) as compared to those containing the anatase phase or mixed phases. Density functional theory calculation shows that TiO2 nanofibers with pure rutile phase have stronger adsorption ability to Pt atoms than anatase phase, which favors the reduction of Pt over rutile phase TiO2, leading to higher contents of metallic Pt in the nanocomposite. In addition, the Pt/TiO2 with rutile phase possesses more abundant oxygen vacancies, which is conducive to the activation of adsorbed oxygen. Consequently, the Pt/rutile-TiO2 nanocomposite exhibited better catalytic activity towards HCHO oxidation at room temperature.

  17. A flexible electrostatic kinetic energy harvester based on electret films of electrospun nanofibers

    Science.gov (United States)

    Lu, Y.; Capo-Chichi, M.; Leprince-Wang, Y.; Basset, P.

    2018-01-01

    This paper reports a paper-based electrostatic kinetic energy harvester (e-KEH) implementing multilayered electret films based on electrospun nanofibrous material. It is the first time that a fully flexible electret-based e-KEH is reported. The proposed electret, PVDF-PTFD nanofibrous covered by Parylene C, has a faster stabilization of surface potential than a planar thin film of Parylene C, and a higher stability of charge storage. With a maximum force of 0.5 N and a 3-layer electret, the device capacitance increases from 25 to 100 pF during a pressing operation. Working with the optimal resistive load of 16 MΩ, the device pressed manually delivers a peak instantaneous power up to 45.6 μW and an average energy of 54 nJ/stroke, corresponding to a peak instantaneous power density of 7.3 μW cm‑2 and an average energy density of 8.6 nJ cm‑2/stroke. Within 450 manual strokes, a 10 nF capacitor is charged up to 8.5 V by the prototype through a full-wave diode bridge. On a 1 μF capacitor, the energy delivery of 9.9 nJ/stroke has been obtained with a 10 Hz pressing movement excited by a vibrator with a maximum force of 0.5 N.

  18. The potential applications of fibrin-coated electrospun polylactide nanofibers in skin tissue engineering.

    Science.gov (United States)

    Bacakova, Marketa; Musilkova, Jana; Riedel, Tomas; Stranska, Denisa; Brynda, Eduard; Zaloudkova, Margit; Bacakova, Lucie

    2016-01-01

    Fibrin plays an important role during wound healing and skin regeneration. It is often applied in clinical practice for treatment of skin injuries or as a component of skin substitutes. We prepared electrospun nanofibrous membranes made from poly(l-lactide) modified with a thin fibrin nanocoating. Fibrin surrounded the individual fibers in the membrane and also formed a thin fibrous mesh on several places on the membrane surface. The cell-free fibrin nanocoating remained stable in the cell culture medium for 14 days and did not change its morphology. On membranes populated with human dermal fibroblasts, the rate of fibrin degradation correlated with the degree of cell proliferation. The cell spreading, mitochondrial activity, and cell population density were significantly higher on membranes coated with fibrin than on nonmodified membranes, and this cell performance was further improved by the addition of ascorbic acid in the cell culture medium. Similarly, fibrin stimulated the expression and synthesis of collagen I in human dermal fibroblasts, and this effect was further enhanced by ascorbic acid. The expression of beta1-integrins was also improved by fibrin, and on pure polylactide membranes, it was slightly enhanced by ascorbic acid. In addition, ascorbic acid promoted deposition of collagen I in the form of a fibrous extracellular matrix. Thus, the combination of nanofibrous membranes with a fibrin nanocoating and ascorbic acid seems to be particularly advantageous for skin tissue engineering.

  19. Preparation, in vitro mineralization and osteoblast cell response of electrospun 13-93 bioactive glass nanofibers.

    Science.gov (United States)

    Deliormanlı, Aylin M

    2015-08-01

    In this study, silicate based 13-93 bioactive glass fibers were prepared through sol-gel processing and electrospinning technique. A precursor solution containing poly (vinyl alcohol) and bioactive glass sol was used to produce fibers. The mixture was electrospun at a voltage of 20 kV by maintaining tip to a collector distance of 10 cm. The amorphous glass fibers with an average diameter of 464±95 nm were successfully obtained after calcination at 625 °C. Hydroxyapatite formation on calcined 13-93 fibers was investigated in simulated body fluid (SBF) using two different fiber concentrations (0.5 and 1 mg/ml) at 37 °C. When immersed in SBF, conversion to a calcium phosphate material showed a strong dependence on the fiber concentration. At 1mg/ml, the surface of the fibers converted to the hydroxyapatite-like material in SBF only after 30 days. At lower solid concentrations (0.5 mg/ml), an amorphous calcium phosphate layer formation was observed followed by the conversion to hydroxyapatite phase after 7 days of immersion. The XTT (2,3-Bis-(2-Methoxy-4-Nitro-5-Sulfophenyl)-2H-Tetrazolium-5-Carboxanilide) assay was conducted to evaluate the osteoblast cell response to the bioactive glass fibers. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Development of electrospun nanofiber composites for pointof-use water treatment

    Science.gov (United States)

    Peter, Katherine T.

    A range of chemical pollutants now contaminate drinking water sources and present a public health concern, including organic compounds, such as pharmaceuticals and pesticides, and both metalloids and heavy metals, such as arsenic and lead. Metalloids and heavy metals have been detected in private drinking water wells, which do not fall under federal drinking water regulations, as well as in urban tap water, due to the introduction of contamination to the drinking water distribution system. Further, many so-called "emerging organic contaminants," which are present in drinking water sources at detectable levels but have unknown long-term health implications, do not fall under federal drinking water regulations. To protect the health of consumers, drinking water treatment at the point-of-use (POU) (i.e., the tap) is essential. Next-generation POU treatment technologies must require minimal energy inputs, be simple enough to permit broad application among different users, and be easily adaptable for removal of a wide range of pollutants. Nanomaterials, such as carbon nanotubes and iron oxide nanoparticles, are ideal candidates for next-generation drinking water treatment, as they exhibit unique, high reactivity and necessitate small treatment units. However, concerns regarding water pressure requirements and nanomaterial release into the treated supply limit their application in traditional reactor designs. To bridge the gap between potential and practical application of nanomaterials, this study utilizes electrospinning to fabricate composite nanofiber filters that effectively deploy nanomaterials in drinking water treatment. In electrospinning, a high voltage draws a polymer precursor solution (which can contain nanomaterial additives, in the case of nanocomposites) from a needle to deposit a non-woven nanofiber filter on a collector surface. Using electrospinning, we develop an optimized, macroporous carbon nanotube-carbon nanofiber composite that utilizes the

  1. Functional properties of electrospun NiO/RuO{sub 2} composite carbon nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Wu Yongzhi [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, National University of Singapore, Singapore 117576 (Singapore); Physics Department, National University of Singapore, Singapore 117542 (Singapore); NUS Graduate School for Integrated Science and Engineering, 10 Kent Ridge Crescent, National University of Singapore, Singapore 119260 (Singapore); Balakrishna, Rajiv [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, National University of Singapore, Singapore 117576 (Singapore); Physics Department, National University of Singapore, Singapore 117542 (Singapore); Reddy, M.V., E-mail: phymvv@nus.edu.sg [Physics Department, National University of Singapore, Singapore 117542 (Singapore); Nair, A. Sreekumaran, E-mail: nniansn@nus.edu.sg [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, National University of Singapore, Singapore 117576 (Singapore); Chowdari, B.V.R. [Physics Department, National University of Singapore, Singapore 117542 (Singapore); Ramakrishna, S. [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, National University of Singapore, Singapore 117576 (Singapore); Kind Saud University, Riyadh 11451 (Saudi Arabia)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Fabrication of carbon nanofibers with nickel-ruthenium composites by electrospinning. Black-Right-Pointing-Pointer An interesting observation of increase in capacitance with increase in the number of cycles for supercapacitor applications. Black-Right-Pointing-Pointer Li ion battery testing showed a stable capacity ranging from 350 mAh g{sup -1} to 400 mAh g{sup -1}. Black-Right-Pointing-Pointer Lower impedance with the incorporation of 15 wt% Ru precursor than those without Ru. - Abstract: One-dimensional (1D) nickel oxide/ruthenium oxide (NiO/RuO{sub 2})-carbon composite nanofibers (NiRu-C-NFs) were fabricated via electrospinning of a homogenous mixture of polyacrylonitrile (PAN) and Ni/Ru salt precursors at different ratios followed by heat treatments. The 1D nanostructures of the composite material were characterized by field-emission scanning electron microscopy (FE-SEM), powder X-ray diffraction (XRD), Rietveld refinement and Brunauer-Emmett-Teller (BET) surface area measurements. Li-cycling properties were evaluated using cyclic voltammetry and galvanostatic properties. The asymmetric hybrid supercapacitor studies were carried out with activated carbon as a cathode and NiRu-C-NFs composites as anodes in the cycling range, 0.005-3.0 V using 1 M LiPF{sub 6} (EC;DMC) electrolyte. NiRu-C-NFs fabricated from 5 wt% nickel (II) and 15 wt% ruthenium (III) precursors showed a capacitance up to {approx}60 F g{sup -1} after 30 cycles. Anodic Li-cycling studies of NiRu-C-NF-0 and NiRu-C-NF-2 composite samples showed a reversible capacity of 230 and 350 m Ahg{sup -1} at current rate of 72 mA g{sup -1} at the end of 40th cycle in the voltage range of 0.005-3.0 V. Electrochemical impedance studies (EIS) on NiRu-C-NFs showed lower impedance value for 15 wt% Ru than the bare sample.

  2. Comparison of photocatalytic properties of TiO2 thin films and fibers

    Science.gov (United States)

    Ozdemir, Mehtap; Kurt, Metin; Ozyuzer, Lutfi; Aygun, Gulnur

    2016-10-01

    Efficiency of solar panels degrades as a result of organic contamination such as airborne particles, bird droppings and leaves. Any foreign object on photovoltaic panels reduces the sunlight entering the absorbing surface of the solar panels. Since this leads to a major problem decreasing in energy production, solar panels should be cleaned. The self-cleaning method can be preferred. There are some methods to clean the surface of solar panels. Among the self-cleaning materials, TiO2 is the most preferable ones because of its powerful photocatalytic properties. In this study, photocatalytic TiO2 were produced in two different nanostructures: nanofibers and thin films. TiO2 nanofibers were successfully produced by electrospinning. TiO2 thin films were fabricated by reactive magnetron sputtering technique. Both TiO2 nanofiber and thin film structures were heat-treated to form TiO2 in anatase phase at 600 °C for 2 h in air. Then, they were evaluated by SEM analyses for morphology, X-ray diffraction (XRD) analyses for phase structures, X-ray photoelectron spectroscopy (XPS) for the chemical state and atomic concentration, and UV-spectrometer for photocatalytic performance. The results indicate that photocatalytic and transmittance properties of TiO2 thin films are better than those of nanofibers. Consequently, TiO2 based thin films exhibit better performance for solar cell applications due to the surface cleanliness.

  3. Fabrication, structure, and magnetic properties of electrospun Ce{sub 0.96}Fe{sub 0.04}O{sub 2} nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Sonsupap, Somchai [School of Physics, Suranaree University of Technology, Nakhon Ratchasima (Thailand); Kidkhunthod, Pinit; Chanlek, Narong [Synchrotron Light Research Institute, Nakhon Ratchasima (Thailand); Pinitsoontorn, Supree [Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen (Thailand); Maensiri, Santi, E-mail: santimaensiri@g.sut.ac.th [School of Physics, Suranaree University of Technology, Nakhon Ratchasima (Thailand); NANOTEC-SUT Center of Excellence on Advanced Functional Nanomaterials, Suranaree University of Technology, Nakhon Ratchasima (Thailand)

    2016-09-01

    Highlights: • Intrinsic ferromagnetism in electrospun nanofibers of Ce{sub 0.96}Fe{sub 0.04}O{sub 2} is reported. • The prepared samples were well characterized by XRD, TEM, XANES, XPS, and VSM. • Ce{sub 0.96}Fe{sub 0.04}O{sub 2} samples are ferromagnetic having Ms of 0.002–0.923 emu/g at 10 kOe. • Oxygen vacancies play an important role to induce room temperature ferromagnetism. • Ferromagnetism observed in Ce{sub 0.96}Fe{sub 0.04}O{sub 2} is intrinsic. - Abstract: We report room temperature ferromagnetism in ∼30–60 nm nanofibers of Ce{sub 0.96}Fe{sub 0.04}O{sub 2} calcined at 500, 600, 700, and 800 °C. The as-spun nanofibers were fabricated by electrospinning technique. Nanofibers of the as-spun and calcined samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and vibrating sample magnetometer (VSM). The XRD and TEM with selected electron diffraction (SEAD) analysis results indicate that the Ce{sub 0.96}Fe{sub 0.04}O{sub 2} nanofibers have a cubic perovskite structure without any secondary phase. The as-spun samples exhibit a diamagnetic behavior, whereas the calcined Ce{sub 0.96}Fe{sub 0.04}O{sub 2} samples are ferromagnetic having the specific magnetizations of 0.002–0.923 emu/g at 10 kOe. The results from XAS spectra show the valence state of Fe{sup 3+} and Fe{sup 2+} mixed in the Ce{sub 0.96}Fe{sub 0.04}O{sub 2} samples indicating oxygen vacancies in the nanofibers. Similarly, the results XPS spectra show that there are oxygen vacancies in the nanofibers as a result of Ce{sup 3+} on the surface. These oxygen vacancies play an important role to induce room temperature ferromagnetism (RT-FM) in the calcined Ce{sub 0.96}Fe{sub 0.04}O{sub 2} nanofibers. Our results indicate that the ferromagnetic properties of Ce{sub 0.96}Fe{sub 0.04}O{sub 2} system are intrinsic and are not a result of

  4. Production of electrospun gelatin nanofibers: an optimization study by using Taguchi’s methodology

    Science.gov (United States)

    İnanç Horuz, Tuğba; Bülent Belibağlı, K.

    2017-01-01

    Electrospinning of gelatin from its solution with a non-toxic solvent is not easy. It certainly requires understanding the effects of critical parameters during electrospinning. In this paper, the first aim was to understand how the morphology and diameter of fibers produced from a solution of gelatin in acetic acid (HAc) were affected by solvent concentration and process parameters (flow-rate, applied voltage, distance between the needle-tip and collector) by using Taguchi’s orthogonal design. For this purpose, the optimum levels of factors were determined as follows: voltage 18 kV, flow rate 15 µl min-1, distance 12.5 cm, and HAc concentration 20% in order to obtain the thinnest nanofiber. Secondly, this combination was further validated by conducting a confirmatory experiment using five different gelatin concentrations to observe the effect of concentration. The average diameters of fibers with 24 and 28% gelatin concentrations were found as similar to the optimum conditions estimated, proving the applicability of Taguchi’s method for electrospinning optimization.

  5. Influence of the collector and heat treatment in the structure of BiFeO{sub 3} electrospun nanofibers; Influencia do coletor e do tratamento termico na estrutura de nanofibras eletrofiadas de BiFeO3

    Energy Technology Data Exchange (ETDEWEB)

    Melo, G.H.F.; Santos, J.P.F.; Bretas, R.E.S., E-mail: bretas@ufscar.br [Universidade Federal de Sao Carlos (DEMa/UFSCar). SP (Brazil). Departamento de Engenharia de Materiais

    2016-07-01

    The objective of this work was to analyze the influence of the collector type and heat treatment on the morphology and crystalline phases of BiFeO{sub 3} electrospun nanofibers. A solution containing (Fe(NO{sub 3}){sub 3.9}H{sub 2}O and Bi(NO{sub 3}){sub 3.5}H{sub 2}O) as precursors together with a polyvinylpyrrolidone solution was electrospun using 2.8KV/cm as electrical field. The collector type was however, changed (aluminum and glass). After the electrospinning, the as-spun nanofibers were submitted to two different heat treatments: one at 550°C and the other at 750°C, both during 2h. The collector type changed the morphology of the nanofibers; while in the glass collector, a non-woven mat of flat and rough nanofibers was obtained, in the aluminum collector, mats of circular and smooth nanofibers were obtained. The thermal treatment also changed the morphology and amount of crystalline phases; at 550°C, the nanofiber morphology was maintained and only one crystalline phase (BiFeO{sub 3}) was detected. On the other hand, at 750°C, flakes were obtained of two crystalline phases (BiFeO{sub 3} and Bi{sub 2}Fe{sub 4}O{sub 9}). (author)

  6. Improved sensitivity of wearable nanogenerators made of electrospun Eu3+ doped P(VDF-HFP)/graphene composite nanofibers for self-powered voice recognition

    Science.gov (United States)

    Adhikary, Prakriti; Biswas, Anirban; Mandal, Dipankar

    2016-12-01

    Composite nanofibers of Eu3+ doped poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP))/graphene are prepared by the electrospinning technique for the fabrication of ultrasensitive wearable piezoelectric nanogenerators (WPNGs) where the post-poling technique is not necessary. It is found that the complete conversion of the piezoelectric β-phase and the improvement of the degree of crystallinity is governed by the incorporation of Eu3+ and graphene sheets into P(VDF-HFP) nanofibers. The flexible nanocomposite fibers are associated with a hypersensitive electronic transition that results in an intense red light emission, and WPNGs also have the capability of detecting external pressure as low as ~23 Pa with a higher degree of acoustic sensitivity, ~11 V Pa-1, than has ever been previously reported. This means that ultrasensitive WPNGs can be utilized to recognize human voices, which suggests they could be a potential tool in the biomedical and national security sectors. The capacitor’s ability to charge from abundant environmental vibrations, such as music, wind, body motion, etc, drives WPNGs as a power source for portable electronics. This fact may open up the prospect of using the Eu3+ doped P(VDF-HFP)/graphene composite electrospun nanofibers, with their multifunctional properties such as vibration sensitivity, wearability, red light emission capability and piezoelectric energy harvesting, for various promising applications in portable electronics, health care monitoring, noise detection and security monitoring.

  7. Preparation of graphene oxide/poly (3,4-ethylenedioxytriophene): Poly (styrene sulfonate) (PEDOT:PSS) electrospun nanofibers

    Energy Technology Data Exchange (ETDEWEB)

    Efelina, Vita; Widianto, Eri [Department of Physics, Universitas Gadjah Mada, Sekip Utara BLS.21 Yogyakarta, 55281 Indonesia (Indonesia); Rusdiana, Dadi [Department of Physical Education, Universitas Pendidikan Indonesia, Bandung (Indonesia); Nugroho, A. A. [Department of Physics, Institut Teknologi Bandung, Jl. Ganesha 10 Bandung (Indonesia); Kusumaatmaja, Ahmad; Triyana, Kuwat; Santoso, Iman, E-mail: iman.santoso@ugm.ac.id [Department of Physics, Universitas Gadjah Mada, Sekip Utara BLS.21 Yogyakarta, 55281 Indonesia (Indonesia); Nanomaterials Research Group, Universitas Gadjah Mada,, Sekip Utara, Yogyakarta (Indonesia)

    2016-04-19

    Graphene oxide (GO)/Poly (3,4-Ethylenedioxytriophene):Poly (styrene Sulfonate) (PEDOT:PSS) nanofibers have been successfully fabricated by a simple electrospinning technique to develop conductive nanofibers with polyvinyl alcohol (PVA) act as a carrier solution. Graphene oxide has been synthesized by Hummer’s method and has been confirmed by Raman Spectroscopy, FTIR and UV-Vis Spectroscopy. GO/PEDOT:PSS composite nanofibers. The structural and morphological properties were characterized by Scanning Electron Microscopy (SEM). The result of SEM show that GO/PEDOT:PSS nanofibers has a relatively uniform morphology nanofiber with diameter between 180 nm - 340 nm with smooth nanofiber surface. The produced nanofibers from this study can be utilized for various applications such as flexible, conductive and transparent electrode.

  8. Thermomechanical Properties of Lignin-Based Electrospun Nanofibers and Films Reinforced with Cellulose Nanocrystals: A Dynamic Mechanical and Nanoindentation Study

    Science.gov (United States)

    Mariko Ago; Joseph E. Jakes; Orlando J. Rojas

    2013-01-01

    We produced defect-free electrospun fibers from aqueous dispersions of lignin, poly(vinyl alcohol) (PVA), and cellulose nanocrystals (CNCs), which were used as reinforcing nanoparticles. The thermomechanical performance of the lignin-based electrospun fibers and the spin-coated thin films was improved when they were embedded with CNCs. Isochronal dynamic mechanical...

  9. Fabrication of a biomimetic ZeinPDA nanofibrous scaffold impregnated with BMP-2 peptide conjugated TiO2 nanoparticle for bone tissue engineering.

    Science.gov (United States)

    Sekar, Babitha; Annamalai, Meenakshi; Dykas, Michal Marcin; Saha, Surajit; Poddar, Kingshuk; Venugopal, Jayarama Reddy; Ramakrishna, Seeram; Venkatesan, Thirumalai; Korrapati, Purna Sai

    2017-09-04

    A biomimetic Zein polydopamine (PDA) based nanofiber scaffold was fabricated to deliver bone morphogenic protein-2 (BMP-2) peptide conjugated titanium dioxide (TiO2 ) nanoparticles in a sustained manner for investigating its osteogenic differentiation potential. To prolong its retention time at the target site, BMP-2 peptide has been conjugated to TiO2 nanoparticles owing to its high surface to volume ratio. The effect of biochemical cues from BMP-2 peptide and nano topographical stimulation of electrospun Zein PDA nanofibers were examined for its enhanced osteogenic expression of human fetal osteoblast (hFOB) cells. The sustained delivery of bioactive signals, improved cell adhesion, mineralization and differentiation could be attributed to its highly interconnected nanofibrous matrix with unique material composition. Further, the expression of osteogenic markers revealed that the fabricated nanofibrous scaffold possess better cell - biomaterial interactions. These promising results demonstrate the potential of the composite nanofibrous scaffold as an effective biomaterial substrate for bone regeneration. This article is protected by copyright. All rights reserved.

  10. Development, optimization and evaluation of polymeric electrospun nanofiber: A tool for local delivery of fluconazole for management of vaginal candidiasis.

    Science.gov (United States)

    Sharma, Rahul; Garg, Tarun; Goyal, Amit K; Rath, Goutam

    2016-01-01

    The present study is designed to explore the localized delivery of fluconazole using mucoadhesive polymeric nanofibers. Drug-loaded polymeric nanofibers were fabricated by the electrospinning method using polyvinyl alcohol (PVA) as the polymeric constituent. The prepared nanofibers were found to be uniform, non-beaded and non-woven, with the diameter of the fibers ranging from 150 to 180 nm. Further drug release studies indicate a sustained release of fluconazole over a period of 6 h. The results of studies on anti-microbial activity indicated that drug-loaded polymeric nanofibers exhibit superior anti-microbial activity against Candida albicans, when compared to the plain drug.

  11. Hierarchically Structured Electrospun Fibers

    Science.gov (United States)

    2013-01-07

    polymer, followed by degradation of the host polymer and reduction [35]. The electrospinning field is extremely broad, and consequently there have...incorporated Ti02 and graphene nanoparticles into PS and polyvinyl chloride nanofibers in order to generate self-cleaning photoelectrodes for dye ...mesoporous 1D TiO2 nanofibers as photovoltaic and photocatalytic materials. Nanoscale 2012, 4, 1707–1716. 35. Wu, H.; Hu, L.; Rowell, M.W.; Kong, D

  12. One-dimensional hierarchical heterostructures of In₂S₃ nanosheets on electrospun TiO₂ nanofibers with enhanced visible photocatalytic activity.

    Science.gov (United States)

    Zhang, Xin; Li, Xinghua; Shao, Changlu; Li, Jinhuan; Zhang, Mingyi; Zhang, Peng; Wang, Kexin; Lu, Na; Liu, Yichun

    2013-09-15

    In₂S₃ nanosheets were assembled on electrospun TiO₂ nanofibers template by a hydrothermal technique. For the obtained one-dimensional In₂S₃/TiO₂ hierarchical heterostructures (1D In₂S₃/TiO₂ H-HSs), the density and size of the secondary In₂S₃ nanosheets could be controlled by adjusting the reactant concentrations for the preparation of In₂S₃ in the hydrothermal process. The 1D In₂S₃/TiO₂ H-HSs exhibited higher visible-light photocatalytic activity for the degradation of Methyl orange (MO) and the reduction of Cr(VI), as compared with the pure TiOv nanofibers and pure In₂S₃ nanosheets. The enhanced visible light photocatalytic activity might be attributed to the extended absorption in the visible light region from the narrow band-gap In₂S₃, the effective photogenerated electron-hole separation by the photosynergistic effects of the In₂S₃/TiO₂ H-HSs and quick electron-transfer in the 1D TiO₂ nanofibers. Meanwhile, the 1D In₂S₃/TiO₂ H-HSs could be recycled easily by sedimentation due to their nanofibrous nonwoven web structure. Moreover, the mechanisms of photodegradation of MO and photoreduction of Cr(VI) were proposed through systematical investigations. This work provided new insights into utilizing 1D In₂S₃/TiO₂ H-HSs as high efficiency visible-light-driven photocatalysts for environmental remediation and energy conversion. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. A comparative study for lipase immobilization onto alginate based composite electrospun nanofibers with effective and enhanced stability.

    Science.gov (United States)

    İspirli Doğaç, Yasemin; Deveci, İlyas; Mercimek, Bedrettin; Teke, Mustafa

    2017-03-01

    In this study, lipase was successfully immobilized on polyvinyl alcohol/alginate and polyethylene oxide/alginate nanofibers that were prepared by electrospinning. Results showed that nanofibers (especially polyvinyl alcohol/alginate) enhanced the stability properties of lipase. When the free lipase lost its all activity after 40-60min at high temperatures, both lipase immobilized nanofibers kept almost 65-70% activity at the same time. The lipase immobilized poly vinyl alcohol/alginate and polyethylene oxide/alginate nanofibers protected approximately all of their activities until pH 9. Lipase immobilized polyvinyl alcohol/alginate and polyethylene oxide/alginate nanofibers maintained 60% of their activities after 14 and 7 reuses, respectively. The morphology of nanofibers was characterized by Scanning Electron Microscope, Fourier Transform Infrared Spectroscopy and Thermal Gravimetric Analyzer. As a result, this nanofiber production method, electrospinning, is simple, versatile and economical for preparing appropriate carrier to immobilize the enzymes. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Antiproliferative activity of ferulic acid-encapsulated electrospun PLGA/PEO nanofibers against MCF-7 human breast carcinoma cells.

    Science.gov (United States)

    Vashisth, Priya; Sharma, Mohit; Nikhil, Kumar; Singh, Harmeet; Panwar, Richa; Pruthi, Parul A; Pruthi, Vikas

    2015-06-01

    Ferulic acid (FA) is a polyphenolic phytonutrient which possesses strong antiproliferative effect; however, it has limited therapeutic applications due to its physiochemical instability and low bioavailability at the tumor site. In present study, these shortcomings associated with FA were overcome by fabricating FA-encapsulated poly(D,L-lactide-co-glycolide)/polyethylene oxide (PLGA/PEO) blend nanofibers using electrospinning technique. FESEM and fluorescence microscopic analysis imitates the smooth morphology and even distribution of FA within the polymeric nanofibers at optimum 2 wt% concentration of FA. The average diameters were recorded to be 150 ± 47.4 and 200 ± 79 nm for PLGA/PEO and FA-encapsulated PLGA/PEO nanofibers, respectively. The encapsulation, compatibility, and physical state of FA within the nanofibers were further confirmed by FTIR, TGA and XRD analysis. In vitro drug delivery studies demonstrated initial burst liberation of FA within 24 h followed by a sustained release for the subsequent time. MTT assay revealed the effectiveness of FA-encapsulated nanofibers against human breast carcinoma cells (MCF-7) cells as compared to control. FESEM and fluorescence microscopic analysis further confirmed the apoptotic effect of FA-encapsulated PLGA/PEO nanofibers against MCF-7. These fabricated nanofibers hold enormous potential to be used as a therapeutic agent for various biomedical applications.

  15. Titanium dioxide-coated nanofibers for advanced filters

    Science.gov (United States)

    Lee, Byung-Yong; Behler, Kris; Kurtoglu, Murat Erdem; Wynosky-Dolfi, Meghan Ann; Rest, Richard F.; Gogotsi, Yury

    2010-09-01

    This article reports on titanium dioxide (TiO2)-coated nanofibers deposited on a filter surface by the electrospinning process. After depositing a micrometer-thick film of polyamide 11 nanofibers on polypropylene fabric, TiO2 nanoparticles can be directly electrosprayed onto the nanofibers. X-ray diffraction and Raman spectroscopy showed minimal change in the phase composition (anatase and rutile) and no change in the particle size of nanocrystalline TiO2 after coating. Scanning electron microscopy demonstrated that nanofibers were uniformly coated by titanium dioxide nanoparticles without agglomeration. TiO2-coated filters showed excellent photocatalytic-bactericidal activity and photo-induced hydrophilicity.

  16. Polyurethane/hydroxypropyl cellulose electrospun nanofiber mats as potential transdermal drug delivery system: characterization studies and in vitro assays.

    Science.gov (United States)

    Gencturk, A; Kahraman, E; Güngör, S; Özhan, G; Özsoy, Y; Sarac, A S

    2017-05-01

    Donepezil hydrochloride containing polyurethane/hydroxypropyl cellulose (PU/HPC) nanofibers were prepared by the electrospinning for transdermal drug delivery. PU/HPC nanofibers were characterized with SEM, DSC, and Pascal mercury porosimetry. Drug-excipient interaction was studied by ATR-FTIR. In vitro release of PU/HPC nanofiber mat (10:2:1) exhibited Korsmeyer-Peppas release kinetics controlled by the diffusion of drug. In vitro permeation studies across skin resembling synthetic membrane demonstrated the flux of model drug. The in vitro cytotoxicity data obtained via MTT assay indicated that PU/HPC nanofiber mat could be well tolerated by the skin and the components was not irritant for the skin.

  17. Modification of electrospun polyacrylonitrile nanofibers with EDTA for the removal of Cd and Cr ions from water effluents

    Energy Technology Data Exchange (ETDEWEB)

    Chaúque, Eutilério F.C., E-mail: efchauque@gmail.com [Department of Applied Chemistry, University of Johannesburg, Doornfontein 2028, Johannesburg (South Africa); Dlamini, Langelihle N., E-mail: lndlamini@uj.ac.za [Department of Applied Chemistry, University of Johannesburg, Doornfontein 2028, Johannesburg (South Africa); Adelodun, Adedeji A., E-mail: aadelodun@uj.ac.za [Department of Applied Chemistry, University of Johannesburg, Doornfontein 2028, Johannesburg (South Africa); Greyling, Corinne J., E-mail: GreylingC@cput.ac.za [Technology Station in Clothing and Textiles, Cape Peninsula University of Technology, Symphony Way, Bellville, 7535 (South Africa); Catherine Ngila, J., E-mail: jcngila2002@yahoo.com [Department of Applied Chemistry, University of Johannesburg, Doornfontein 2028, Johannesburg (South Africa)

    2016-04-30

    Graphical abstract: - Highlights: • Polyscrylonitrile (PAN) nanofibers prepared through electrospinning and chemically modified with ethylenediaminetetraacetic acid using ethylenediamine crosslinker. • Fabricated nanofibers have enhanced surface chemistry with insignificant impact on the nanofibrous structure. • Excellent maximum adsorption capacities of 66.24 and 32.68 mg g{sup −1} toward Cr and Cd ions, respectively. • A pre-concentration factor of 19 achieved for removal of Cd and Cr in environmental water samples. - Abstract: Polyacrylonitrile (PAN) nanofibers were obtained by electrospinning technique prior to surface modification with polyethylenediaminetetraacetic acid (EDTA) using ethylenediamine (EDA) as the cross-linker. The modified nanofibers (EDTA-EDA-PAN) were subsequently applied in the wastewater treatment for the removal of Cd(II) and Cr(VI). Textural and chemical characterizations of the nanofibers were carried out by analysis of the specific surface area (Brauner Emmet and Teller (BET)) and thermogravimetric analyses, scanning electron microscopy and Fourier transform infrared spectroscopy. From the adsorption equilibrium studies with Langmuir, Freundlich and Temkin isotherm models, Freundlich was found most suitable for describing the removal mechanism of the target metals as they collect on a heterogeneously functionalized polymer surface. The EDTA-EDA-PAN nanofibers showed effective sorption affinity for both Cd(II) and Cr(VI), achieving maximum adsorption capacities of 32.68 and 66.24 mg g{sup -1}, respectively, at 298 K. In furtherance, the nanofibers were regenerated by simple washing with 2 M HCl solution. Conclusively, the EDTA-EDA-PAN nanofibers were found to be efficient for the removal of Cd(II) and Cr(VI) in water effluents.

  18. Non-woven and aligned electrospun multicomponent luminescent polymer nanofibers: effects of aggregated morphology on the photophysical properties.

    Science.gov (United States)

    Wang, Cheng-Ting; Kuo, Chi-Ching; Chen, Hsieh-Chih; Chen, Wen-Chang

    2009-09-16

    In this paper, the morphology and photophysical properties of non-woven and aligned ES nanofibers prepared from the ternary blends of poly(9,9-dioctylfluorenyl-2,7-diyl) (PFO) / poly(2,3-dibutoxy-1,4-phenylene vinylene) (DB-PPV) / poly(methyl methacrylate) (PMMA) using a single-capillary spinneret are reported. Various PFO and DB-PPV phase-separated structures in the ES nanofibers were found by two different solvents: ellipsoidal DB-PPV (10-40 nm) and fiber-like PFO (20-40 nm) in the PMMA using chloroform, while fiber-like DB-PPV (10-20 nm) and fiber-like PFO (20-30 nm) using chlorobenzene. Such different PFO and DB-PPV structures resulted in various energy transfer/emission colors in the ES nanofibers. Moreover, highly aligned luminescence PFO/DB-PPV/PMMA blend ES nanofibers prepared from chlorobenzene showed a much higher polarized emission than the non-woven and the emission colors changed from blue to greenish-blue to green as the DB-PPV composition increased. The different polarized emission characteristics between PFO and DB-PPV in the ES nanofibers also led to varied emission colors at different angles. The present study suggests the morphologies and emission characteristics of the multicomponent ES nanofibers could be efficiently tuned through solvent types and blend ratios of semiconducting polymers.

  19. Modification of electrospun polyacrylonitrile nanofibers with EDTA for the removal of Cd and Cr ions from water effluents

    Science.gov (United States)

    Chaúque, Eutilério F. C.; Dlamini, Langelihle N.; Adelodun, Adedeji A.; Greyling, Corinne J.; Catherine Ngila, J.

    2016-04-01

    Polyacrylonitrile (PAN) nanofibers were obtained by electrospinning technique prior to surface modification with polyethylenediaminetetraacetic acid (EDTA) using ethylenediamine (EDA) as the cross-linker. The modified nanofibers (EDTA-EDA-PAN) were subsequently applied in the wastewater treatment for the removal of Cd(II) and Cr(VI). Textural and chemical characterizations of the nanofibers were carried out by analysis of the specific surface area (Brauner Emmet and Teller (BET)) and thermogravimetric analyses, scanning electron microscopy and Fourier transform infrared spectroscopy. From the adsorption equilibrium studies with Langmuir, Freundlich and Temkin isotherm models, Freundlich was found most suitable for describing the removal mechanism of the target metals as they collect on a heterogeneously functionalized polymer surface. The EDTA-EDA-PAN nanofibers showed effective sorption affinity for both Cd(II) and Cr(VI), achieving maximum adsorption capacities of 32.68 and 66.24 mg g-1, respectively, at 298 K. In furtherance, the nanofibers were regenerated by simple washing with 2 M HCl solution. Conclusively, the EDTA-EDA-PAN nanofibers were found to be efficient for the removal of Cd(II) and Cr(VI) in water effluents.

  20. Nano silver-embedded electrospun nanofiber of poly(4-chloro-3-methylphenyl methacrylate): use as water sanitizer.

    Science.gov (United States)

    Shekh, Mehdihasan I; Patel, Nirmal N; Patel, Kaushal P; Patel, Rajnikant M; Ray, Arabinda

    2017-02-01

    Water contaminated with microorganisms causes numerous diseases and is a major concern for public health. In search of a simple material which can provide clean water free from pathogens, nanofibers of poly(4-chloro-3-methylphenyl methacrylate, abbreviated as CMPMA, and nano Ag-doped poly(CMPMA) composite nanofibers were used to decontaminate water from microorganisms such as Escherichia coli and Bacillus subtilis. Nanofibers were prepared by electrospinning. X-ray diffraction (XRD) and transmission electron microscopy (TEM) provide the diameters of the Ag nanoparticles which are in the range 18-21 and 13-18 nm. The diameter of the poly(CMPMA) and nano Ag-doped poly(CMPMA) composite nanofiber is seen to vary between 400 and 700 nm with the change of the processing parameters. Optimum parameters for uniform nanofibers have been obtained. The morphology of the fibers is derived from scanning electron microscopy (SEM). The superiority of the nano Ag-doped poly(CMPMA) composite nanofiber was established.

  1. Efficient adsorption and antibacterial properties of electrospun CuO-ZnO composite nanofibers for water remediation

    Energy Technology Data Exchange (ETDEWEB)

    Malwal, Deepika [Nanobiotechnology Laboratory, Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667 (India); Gopinath, P., E-mail: pgopifnt@iitr.ernet.in [Nanobiotechnology Laboratory, Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667 (India); Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, Uttarakhand 247667 (India)

    2017-01-05

    Highlights: • Synthesis of CuO-ZnO composite nanofibers using simple electrospinning technique. • Characterization data confirmed the proper structure. • Exploited as effective adsorbent for congo red dye. • Several adsorption kinetic and isotherm models were discussed. • Evaluation of antibacterial activity against GFP-E.coli and S. aureus. - Abstract: On the face of impending global water resources, developing low-cost and efficient water treatment technologies and materials thereof is highly important. Herein, we explore the adsorption capacity and antibacterial properties of CuO-ZnO (CZ) composite nanofibers. The ultrafine nanofibers were fabricated using simple and inexpensive electrospinning technique and were further characterized using Field Emission-Scanning Electron Microscope (FE-SEM), Transmission electron microscope (TEM) and X-Ray Diffraction (XRD), Thermogravimetric analysis (TGA), Fourier transform Infrared Spectroscopy (FTIR). When employed as nanoadsorbents, CZ nanofibers exhibited excellent adsorption capacity for congo red dye. Adsorption Isotherms and kinetics were performed to determine the maximum adsorption capacity and the rate of adsorption, respectively, depicting the better efficiency of composite nanofibers as compared to their single counterparts. The mechanism of adsorption is also proposed with the evaluation of diffusion studies. The second part of this study deals with the examination of antibacterial activity of CZ composite nanofibers against antibiotic resistant GFP-E.coli and S. aureus. The antibacterial efficacy was monitored by visual turbidity assay, SEM analysis and reactive oxygen species (ROS) determination. Hence, such nanofibers have been explored as a single platform for the removal of biological as well organic contaminants so as to make them potential in the field of water remediation.

  2. Optimization and development of Maghemite (γ-Fe2O3) filled poly-l-lactic acid (PLLA)/thermoplastic polyurethane (TPU) electrospun nanofibers using Taguchi orthogonal array for tissue engineering heart valve.

    Science.gov (United States)

    Fallahiarezoudar, Ehsan; Ahmadipourroudposht, Mohaddeseh; Idris, Ani; Yusof, Noordin Mohd

    2017-07-01

    Tissue engineering (TE) is an advanced principle to develop a neotissue that can resemble the original tissue characteristics with the capacity to grow, to repair and to remodel in vivo. This research proposed the optimization and development of nanofiber based scaffold using the new mixture of maghemite (γ-Fe2O3) filled poly-l-lactic acid (PLLA)/thermoplastic polyurethane (TPU) for tissue engineering heart valve (TEHV). The chemical, structural, biological and mechanical properties of nanofiber based scaffold were characterized in terms of morphology, porosity, biocompatibility and mechanical behaviour. Two-level Taguchi experimental design (L8) was performed to optimize the electrospun mats in terms of elastic modulus using uniaxial tensile test where the studied parameters were flow rate, voltage, percentage of maghemite nanoparticles in the content, solution concentration and collector rotating speed. Each run was extended with an outer array to consider the noise factors. The signal-to-noise ratio analysis indicated the contribution percent as follow; Solution concentration>voltage>maghemite %>rotating speed>flow rate. The optimum elastic modulus founded to be 28.13±0.37MPa in such a way that the tensile strain was 31.72% which provided desirability for TEHV. An empirical model was extracted and verified using confirmation test. Furthermore, an ultrafine quality of electrospun nanofibers with 80.32% porosity was fabricated. The MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and cell attachment using human aortic smooth muscle cells exhibited desirable migration and proliferation over the electrospun mats. The interaction between blood content and the electrospun mats indicated a mutual adaption in terms of clotting time and hemolysis percent. Overall, the fabricated scaffold has the potential to provide the required properties of aortic heart valve. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Facile Functionalization of Electrospun Poly(ethylene-co-vinyl alcohol Nanofibers via the Benzoxaborole-Diol Interaction

    Directory of Open Access Journals (Sweden)

    Yohei Kotsuchibashi

    2016-02-01

    Full Text Available A facile functionalization method of poly(ethylene-co-vinyl alcohol (EVOH nanofiber meshes was demonstrated by utilizing the benzoxaborole-diol interaction between EVOH and benzoxaborole-based copolymers (BOP. EVOH and BOP were firstly mixed to prepare the quasi-gel-state solution with enough viscosity for electro-spinning. The fiber morphology was controlled via changing the mixing ratio of EVOH and BOP. The prepared EVOH/BOP nanofiber mesh showed good stability in aqueous solution. Over 97% of the nanofibers remained after the immersion test for 24 h in acid or alkali aqueous solutions without changing their morphology. Temperature and pH-responsive moieties were copolymerized with BOP, and cationic dye was easily immobilized into the nanofiber mesh via an electrostatic interaction. Therefore, the proposed functionalization technique is possible to perform on multi-functionalized molecule-incorporated nanofibers that enable the fibers to show the environmental stimuli-responsive property for the further applications of the EVOH materials.

  4. Amorphous SiO2 NP-Incorporated Poly(vinylidene fluoride) Electrospun Nanofiber Membrane for High Flux Forward Osmosis Desalination.

    Science.gov (United States)

    Obaid, M; Ghouri, Zafar Khan; Fadali, Olfat A; Khalil, Khalil Abdelrazek; Almajid, Abdulhakim A; Barakat, Nasser A M

    2016-02-01

    Novel amorphous silica nanoparticle-incorporated poly(vinylidine fluoride) electrospun nanofiber mats are introduced as effective membranes for forward osmosis desalination technology. The influence of the inorganic nanoparticle content on water flux and salt rejection was investigated by preparing electrospun membranes with 0, 0.5, 1, 2, and 5 wt % SiO2 nanoparticles. A laboratory-scale forward osmosis cell was utilized to validate the performance of the introduced membranes using fresh water as a feed and different brines as draw solution (0.5, 1, 1.5, and 2 M NaCl). The results indicated that the membrane embedding 0.5 wt % displays constant salt rejection of 99.7% and water flux of 83 L m(-2) h(-1) with 2 M NaCl draw solution. Moreover, this formulation displayed the lowest structural parameter (S = 29.7 μm), which represents approximately 69% reduction compared to the pristine membrane. Moreover, this study emphasizes the capability of the electrospinning process in synthesizing effective membranes as the observed water flux and average salt rejection of the pristine poly(vinylidine fluoride) membrane was 32 L m(-2) h(-1) (at 2 M NaCl draw solution) and 99%, respectively. On the other hand, increasing the inorganic nanoparticles to 5 wt % showed negative influence on the salt rejection as the observed salt flux was 1651 mol m(-2) h(-1). Besides the aforementioned distinct performance, studies of the mechanical properties, porosity, and wettability concluded that the introduced membranes are effective for forward osmosis desalination technology.

  5. Magnetic and optical properties of electrospun hollow nanofibers of SnO2 doped with Ce-ion

    Science.gov (United States)

    Mohanapriya, P.; Pradeepkumar, R.; Victor Jaya, N.; Natarajan, T. S.

    2014-07-01

    Cerium doped SnO2 hollow nanofibers were synthesized by electrospinning. High resolution scanning electron microscope (HRSEM) and transmission electron microscopy (TEM) analysis showed hollow nanofibers with diameters around ˜200 nm. The optimized substitution of Ce ion into SnO2 lattices happened above 6 mol. % doping as confirmed by Powder X-ray diffraction (XRD) studies. Optical band gap was decreased by the doping confirming the direct energy transfer between f-electrons of rare earth ion and the SnO2 conduction or valence band. The compound also exhibited room temperature ferromagnetism with the saturation magnetization of 19 × 10-5 emu/g at 6 mol. %. This study demonstrates the Ce doped SnO2 hollow nanofibers for applications in magneto-optoelectronic devices.

  6. Functional electrospun membranes

    Science.gov (United States)

    Ognibene, G.; Fragalà, M. E.; Cristaldi, D. A.; Blanco, I.; Cicala, G.

    2016-05-01

    In this study we combined electrospun PES nanofibers with ZnO nanostructures in order to obtain a hierarchical nanostructured hybrid material to be use for active water filtration membranes. It benefits of flexibility and high surface area of the polymeric nanofibers as well as of additional functionalities of ZnOnanostructures. First, randomly oriented nanofibers with diameters of 716nm ±365 nm were electrospun on a glass fibers substrate from a solution of PES and DMF-TOL(1:1). ZnO nanorods were grown onto the surface of electrospun PES fibers by a Chemical Bath Deposition (CBD) process. It was preceed by a seeding process necessary to form nucleation sites for the subsequent radially aligned growth of ZnO nanowires. The morfology of the fibers and the effect of the seeding time have been analysed by SEM. The amount of ZnO nanowires grown over electrospun nanofibers was determined as 45% by weight. The high purity and crystallinity of the asobtained products are confirmed by XRD since all reflection peaks can be indexed to hexagonal wurtzite ZnO.

  7. Synthesis of anatase TiO2with exposed (100) facets and enhanced electrorheological activity.

    Science.gov (United States)

    He, Kai; Wen, Qingkun; Wang, Chengwei; Wang, Baoxiang; Yu, Shoushan; Hao, Chuncheng; Chen, Kezheng

    2017-11-08

    Herein, a simple hydrothermal method is employed to synthesize anatase TiO 2 with dominant (100) facets, as a precursor, using titanate nanofibers derived from alkali treatment. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) are carried out to confirm the surface morphology and phase structure of the TiO 2 product. The formation mechanism of TiO 2 enclosed by (100) and (101) facets is deduced to be the selective adsorption of OH - on the (100) facets of anatase TiO 2 . Electroheological (ER) experiments indicate that the tetragonal-facet-rod anatase TiO 2 with exposed (100) facets exhibits an excellent ER performance with a high ER efficiency of up to 52.5, which results from the anisotropy of its special morphology. In addition, the effect of shape on its dielectric property is investigated via broadband dielectric spectroscopy.

  8. One-dimensional hierarchical heterostructures of In{sub 2}S{sub 3} nanosheets on electrospun TiO{sub 2} nanofibers with enhanced visible photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xin; Li, Xinghua; Shao, Changlu, E-mail: clshao@nenu.edu.cn; Li, Jinhuan, E-mail: lijh248@nenu.edu.cn; Zhang, Mingyi; Zhang, Peng; Wang, Kexin; Lu, Na; Liu, Yichun

    2013-09-15

    Graphical abstract: One-dimensional In{sub 2}S{sub 3}/TiO{sub 2} hierarchical heterostructures were fabricated based on TiO{sub 2} nanofibers by combining the electrospinning technique (for TiO{sub 2} nanofibers) with the hydrothermal method (for In{sub 2}S{sub 3} nanosheets), which exhibited a high visible light photocatalytic activity for degradation of Methyl orange and reduction of Cr(VI) under visible light illumination (λ > 420 nm). -- Highlights: • Synthesis of one-dimensional In{sub 2}S{sub 3}/TiO{sub 2} hierarchical heterostructures. • Enhanced visible-light photocatalytic activity. • The mechanisms of photodegradation of MO and photoreduction of Cr(VI). -- Abstract: In{sub 2}S{sub 3} nanosheets were assembled on electrospun TiO{sub 2} nanofibers template by a hydrothermal technique. For the obtained one-dimensional In{sub 2}S{sub 3}/TiO{sub 2} hierarchical heterostructures (1D In{sub 2}S{sub 3}/TiO{sub 2} H-HSs), the density and size of the secondary In{sub 2}S{sub 3} nanosheets could be controlled by adjusting the reactant concentrations for the preparation of In{sub 2}S{sub 3} in the hydrothermal process. The 1D In{sub 2}S{sub 3}/TiO{sub 2} H-HSs exhibited higher visible-light photocatalytic activity for the degradation of Methyl orange (MO) and the reduction of Cr(VI), as compared with the pure TiO{sub 2} nanofibers and pure In{sub 2}S{sub 3} nanosheets. The enhanced visible light photocatalytic activity might be attributed to the extended absorption in the visible light region from the narrow band-gap In{sub 2}S{sub 3}, the effective photogenerated electron–hole separation by the photosynergistic effects of the In{sub 2}S{sub 3}/TiO{sub 2} H-HSs and quick electron-transfer in the 1D TiO{sub 2} nanofibers. Meanwhile, the 1D In{sub 2}S{sub 3}/TiO{sub 2} H-HSs could be recycled easily by sedimentation due to their nanofibrous nonwoven web structure. Moreover, the mechanisms of photodegradation of MO and photoreduction of Cr(VI) were proposed

  9. Effect of thermal treatment on the properties of electrospun LiFePO{sub 4}–carbon nanofiber composite cathode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Changhuan; Liang, Yinzheng; Yao, Lan; Qiu, Yiping, E-mail: ypqiu@dhu.edu.cn

    2015-04-05

    Graphical abstract: The composites prepared with the thermal treatment process of stabilization at 280 °C for 4 h with a heating rate of 2 °C min{sup −1} in air followed by carbonization at 800 °C for 14 h with a heating rate of 2 °C min{sup −1} in argon exhibit the optimal electrochemical properties. - Highlights: • Binder-free LiFePO{sub 4}–CNF composite cathode materials are prepared. • The conductive carbon and LiFePO{sub 4} formation take place simultaneously during thermal treatment. • The reaction behavior of the LiFePO{sub 4} precursors during thermal treatment are investigated. • Different thermal treatment processes would generate different electrochemical performance. • Cycling performance and rate capability are improved with a suitable thermal treatment condition. - Abstract: Binder-free LiFePO{sub 4}–carbon nanofiber (LiFePO{sub 4}–CNF) composites as lithium-ion battery cathode materials are fabricated by electrospinning and subsequent thermal treatments. The thermal decomposition behavior of the electrospun LiFePO{sub 4} precursor–polyacrylonitrile (LiFePO{sub 4} precursor–PAN) nanofiber composites and the reaction of the LiFePO{sub 4} precursors during thermal treatment are investigated. The effects of thermal treatment parameters such as heating rate, temperature, and duration for stabilization and carbonization on the microstructure, morphology, carbon content, crystal structure of the composites, and electrochemical performance of the resultant half-cell are also studied. When the electrospun LiFePO{sub 4} precursor–PAN nanofiber composites are first stabilized in air at 280 °C for 4 h with a heating rate of 2 °C min{sup −1} and then carbonized in argon at 800 °C for 14 h with a heating rate of 2 °C min{sup −1}, the obtained LiFePO{sub 4}–CNF composites exhibit optimal electrochemical properties in terms of a higher initial discharge capacity, more stable charge–discharge cycle behavior, and better rate

  10. Zero percolation threshold in electric conductivity of aluminum nanowire network fabricated by chemical etching using an electrospun nanofiber mask

    Science.gov (United States)

    Azuma, Keisuke; Sakajiri, Koichi; Okabe, Takashi; Matsumoto, Hidetoshi; Kang, Sungmin; Watanabe, Junji; Tokita, Masatoshi

    2017-09-01

    We investigated the sheet resistance (R s) and transmittance (T) of seamless two-dimensional networks of 50-nm-thick aluminum (Al) nanowires (NWs) with widths (W) ranging from 380 to 1410 nm. The Al NWs were fabricated by wet-etching of Al metalized polyester films with using polystyrene (PS) nanofibers as the mask. The PS nanofibers were deposited by the electrospinning of a PS solution and adhered to the film by annealing. W and the area coverage (φ) were increased with increasing PS solution concentration and deposition time, respectively. With increasing φ from 3 to 34%, T and R s decreased from 99 to 75% and from 800 to 10 Ω/sq, respectively, and the network with W = 878 nm at φ = 0.21 attained values of T = 91% and R s = 31 Ω/sq. The conductivity increases with φ with an exponent of 2, demonstrating that seamless NW networks are characterized by the zero percolation threshold.

  11. Electrospinning of nanofibers for filtration media

    Science.gov (United States)

    Park, Hyoungjun

    Since particulate impurity is regarded as the primary cause of lung diseases, purification of air has been a crucial issue. Filtration is the most conventional method to obtain clean air, whereby particulate matter is collected on a fibrous media. The use of fibrous filters is prevalent because of their high filtration efficiency and low pressure drop. Fibrous filters were fabricated via the electrospinning process which can be used to produce continuous submicron-diameter sized fibers. Polyacrylonitrile (PAN) nanofibers with a mean fiber diameter of 224 nm were electrospun to form fibermats. Filtration tests on fibermats of PAN were conducted to confirm that filters of thinner fibers result in higher collection efficiencies and lower pressure drops than that of thicker fibers as predicted by the theoretical filtration mechanism. Results showed that electrospun PAN nanofibermats had a superior quality factor of 0.067+/-0 compared to 0.031+/-0.001 by the current state-of-the-art microfiber-based high particulate air (HEPA) filtration media. The verified theory implies that nanofibermats of other types of materials could also be considered as promising filtration media since filtration performance is independent of the material used. As materials for advanced next-generation filtration media, ceramics are favored over polymeric materials due to their robustness against environmental factors such as ultraviolet rays, abrasive particles, and high temperature all of which degrade and damage the fibrous structure. Amidst various ceramic materials, the anatase phase of TiO2 was selected due to its mechanical property and versatility as a photocatalyst and microwave-absorbing material. Anatase TiO2 fibers were fabricated by electrospinning followed by heat treatment at 500°C for 3 hours. However, early precipitation or gelation of the organic solvent-based TiO2 sol posed a practical challenge in the sample preparation. In order to enhance stability of the precursor sol, a

  12. Treatment of alkali-injured cornea by cyclosporine A-loaded electrospun nanofibers - An alternative mode of therapy.

    Czech Academy of Sciences Publication Activity Database

    Čejková, Jitka; Čejka, Čestmír; Trošan, Peter; Zajícová, Alena; Syková, Eva; Holáň, Vladimír

    2016-01-01

    Roč. 147, may. (2016), s. 128-137 ISSN 0014-4835 R&D Projects: GA ČR(CZ) GA14-12580S; GA MZd(CZ) NT14102; GA MŠk(CZ) LO1309; GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:68378041 Keywords : alkali injury * central corneal thickness * CsA-loaded nanofibers * immunohistochemistry Subject RIV: FF - HEENT, Dentistry Impact factor: 3.332, year: 2016

  13. A Review of the Effect of Processing Variables on the Fabrication of Electrospun Nanofibers for Drug Delivery Applications

    OpenAIRE

    Viness Pillay; Clare Dott; Choonara, Yahya E.; Charu Tyagi; Lomas Tomar; Pradeep Kumar; du Toit, Lisa C.; Ndesendo, Valence M. K.

    2013-01-01

    Electrospinning is a fast emerging technique for producing ultrafine fibers by utilizing electrostatic repulsive forces. The technique has gathered much attention due to the emergence of nanotechnology that sparked worldwide research interest in nanomaterials for their preparation and application in biomedicine and drug delivery. Electrospinning is a simple, adaptable, cost-effective, and versatile technique for producing nanofibers. For effective and efficient use of the technique, several...

  14. Water-insoluble sericin/β-cyclodextrin/PVA composite electrospun nanofibers as effective adsorbents towards methylene blue.

    Science.gov (United States)

    Zhao, Rui; Wang, Yong; Li, Xiang; Sun, Bolun; Jiang, Ziqiao; Wang, Ce

    2015-12-01

    A novel water-insoluble sericin/β-cyclodextrin/poly (vinyl alcohol) composite nanofiber adsorbent was prepared by electrospinning and followed by thermal crosslinking for removal of cationic dye methylene blue from aqueous solution. Fourier transform infrared spectroscopy and solubility experiments confirmed that sericin and β-cyclodextrin were incorporated into the nanofibers and the crosslinking reaction occurred successfully. Kinetics, isotherms and thermodynamics analysis were studied for adsorption of methylene blue. The adsorption process is better fitted with the pseudo-second-order model and Langmuir isotherm model. The maximum adsorption capacities are 187.97, 229.89, and 261.10mg/g at the temperatures 293, 313 and 333 K, respectively. Thermodynamic parameters showed that methylene blue adsorption was endothermic and spontaneous. In addition, the fiber membrane adsorbent could be easily separated from dye solution and showed high recyclable removal efficiency. All these results suggest that crosslinked sericin/β-cyclodextrin/poly(vinyl alcohol) composite nanofibers could be potential recyclable adsorbents in dye wastewater treatment. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Controlled synthesis and photocatalysis of sea urchin-like Fe3O4@TiO2@Ag nanocomposites

    Science.gov (United States)

    Zhao, Yilin; Tao, Chengran; Xiao, Gang; Wei, Guipeng; Li, Linghui; Liu, Changxia; Su, Haijia

    2016-02-01

    Based on the synergistic photocatalytic activities of nano-sized TiO2 and Ag, as well as the magnetic properties of Fe3O4, a sea urchin-like Fe3O4@TiO2@Ag nanocomposite (Fe3O4@TiO2@Ag NCs) is controllably synthesized with tunable cavity size, adjustable shell layer of TiO2 nanofiber, higher structural stability and larger specific surface area. Here, Fe3O4@TiO2@Ag NCs are obtained with Fe3O4 as the core and nanofiber TiO2/Fe3O4/Ag nanoheterojunctions as the shell; and Ag nanoparticles with diameter of approximately 4 nm are loaded both on TiO2 nanofibers and inside the cavities of sea urchin-like Fe3O4@TiO2 nanocomposites uniformly. Ag nanoparticles lead to the production of more photogenerated charges in the TiO2/Fe3O4/Ag heterojunction via LSPR absorption, and enhance the band-gap absorption of TiO2, while the Fe3O4 cocatalyst provides the active sites for oxygen reduction by the effective transfer of photogenerated electrons to oxygen. So the photocatalytic performance is improved due to the synergistic effect of TiO2/Fe3O4/Ag nanoheterojunctions. As photocatalysts under UV and visible irradiation, the as-synthesized nanocomposites display enhanced photocatalytic and recycling properties for the degradation of ampicillin. Moreover, they present better broad-spectrum antibiosis under visible irradiation. The enhanced photocatalytic activity and excellent chemical stability, in combination with the magnetic recyclability, makes this multifunctional nanostructure a promising candidate for antibiosis and remediation in aquatic environmental contamination in the future.Based on the synergistic photocatalytic activities of nano-sized TiO2 and Ag, as well as the magnetic properties of Fe3O4, a sea urchin-like Fe3O4@TiO2@Ag nanocomposite (Fe3O4@TiO2@Ag NCs) is controllably synthesized with tunable cavity size, adjustable shell layer of TiO2 nanofiber, higher structural stability and larger specific surface area. Here, Fe3O4@TiO2@Ag NCs are obtained with Fe3O4 as the

  16. Real-Time Characterization of Electrospun PVP Nanofibers as Sensitive Layer of a Surface Acoustic Wave Device for Gas Detection

    Directory of Open Access Journals (Sweden)

    D. Matatagui

    2014-01-01

    Full Text Available The goal of this work has been to study the polyvinylpyrrolidone (PVP fibers deposited by means of the electrospinning technique for using as sensitive layer in surface acoustic wave (SAW sensors to detect volatile organic compounds (VOCs. The electrospinning process of the fibers has been monitored and RF characterized in real time, and it has been shown that the diameters of the fibers depend mainly on two variables: the applied voltage and the distance between the needle and the collector, since all the electrospun fibers have been characterized by a scanning electron microscopy (SEM. Real-time measurement during the fiber coating process has shown that the depth of penetration of mechanical perturbation in the fiber layer has a limit. It has been demonstrated that once this saturation has been reached, the increase of the thickness of the fibers coating does not improve the sensitivity of the sensor. Finally, the parameters used to deposit the electrospun fibers of smaller diameters have been used to deposit fibers on a SAW device to obtain a sensor to measure different concentrations of toluene at room temperature. The present sensor exhibited excellent sensitivity, good linearity and repeatability, and high and fast response to toluene at room temperature.

  17. Distributed feedback imprinted electrospun fiber lasers.

    Science.gov (United States)

    Persano, Luana; Camposeo, Andrea; Del Carro, Pompilio; Fasano, Vito; Moffa, Maria; Manco, Rita; D'Agostino, Stefania; Pisignano, Dario

    2014-10-01

    Imprinted, distributed feedback lasers are demonstrated on individual, active electrospun polymer nanofibers. In addition to advantages related to miniaturization, optical confinement and grating nanopatterning lead to a significant threshold reduction compared to conventional thin-film lasers. The possibility of imprinting arbitrary photonic crystal geometries on electrospun lasing nanofibers opens new opportunities for realizing optical circuits and chips. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Sol gel growth of titania from electrospun polyacrylonitrile nanofibres

    Science.gov (United States)

    Hong, Youliang; Li, Domgmei; Zheng, Jian; Zou, Guangtian

    2006-04-01

    In this paper we report on the development of TiO2 surface-residing electrospun nanofibres with controllable density of TiO2 on the support fibre surface by means of an electrospinning technique and a sol-gel process. The TiO2 precursor/PAN composite nanofibres were synthesized by electrospinning a polyacrylonitrile (PAN) solution containing TiO2 precursors. Subsequently, an immersion of the electrospun composite nanofibres in deionized water led to the hydrolysis of the TiO2 precursors. SEM, TEM and XRD pattern analyses demonstrated that TiO2 was formed and resided on the nanofibre surface. On further calcining the hydrolysed nanofibres in air at 300 °C, TiO2 could be conveniently converted into anatase without essentially changing the morphology of the hydrolysed nanofibres. Furthermore, surface photovoltage spectroscopy (SPS) confirmed that the TiO2 surface-residing nanofibre nonwovens had a strong SPS response. It can be attributed that the surface residence of TiO2 permits the transfer of the photogenerated electron originating from TiO2 to ITO electrodes. Potential applications of the TiO2 surface-residing nanofibres include filters, catalysis films and environmental pollution remediation films.

  19. Removal of tetracycline from aqueous solution by a Fe3O4 incorporated PAN electrospun nanofiber mat.

    Science.gov (United States)

    Liu, Qing; Zheng, Yuming; Zhong, Lubin; Cheng, Xiaoxia

    2015-02-01

    Pollution of antibiotics, a type of emerging contaminant, has become an issue of concern, due to their overuse in human and veterinary application, persistence in environment and great potential risk to human and animal health even at trace level. In this work, a novel adsorbent, Fe3O4 incorporated polyacrylonitrile nanofiber mat (Fe-NFM), was successfully fabricated via electrospinning and solvothermal method, targeting to remove tetracycline (TC), a typical class of antibiotics, from aqueous solution. Field emission scanning electron microscopy and X-ray diffraction spectroscopy were used to characterize the surface morphology and crystal structure of the Fe-NFM, and demonstrated that Fe-NFM was composed of continuous, randomly distributed uniform nanofibers with surface coating of Fe3O4 nanoparticles. A series of adsorption experiments were carried out to evaluate the removal efficiency of TC by the Fe-NFM. The pseudo-second-order kinetics model fitted better with the experimental data. The highest adsorption capacity was observed at initial solution pH4 while relative high adsorption performance was obtained from initial solution pH4 to 10. The adsorption of TC on Fe-NFM was a combination effect of both electrostatic interaction and complexation between TC and Fe-NFM. Freundlich isotherm model could better describe the adsorption isotherm. The maximum adsorption capacity calculated from Langmuir isotherm model was 315.31 mg/g. Compared to conventional nanoparticle adsorbents which have difficulties in downstream separation, the novel nanofiber mat can be simply installed as a modular compartment and easily separated from the aqueous medium, promising its huge potential in drinking and wastewater treatment for micro-pollutant removal. Copyright © 2014. Published by Elsevier B.V.

  20. Electrically-charged recyclable graphene flakes entangled with electrospun nanofibers for the adsorption of organics for water purification.

    Science.gov (United States)

    An, Seongpil; Jo, Hong Seok; Song, Kyo Yong; Mali, Mukund G; Al-Deyab, Salem S; Yoon, Sam S

    2015-12-07

    Graphene flakes were entrapped between nylon 6 nanofiber layers and the resulting assembly was used as a recyclable water purification membrane. Water purification was achieved via adsorption of the model organic pollutant (methylene blue; MB) on the surface of the graphene component. Desorption of these MB molecules was achieved by applying high voltage, which increased the removal efficiency of the recycled membrane. The adsorption and desorption mechanisms were evaluated in detail. The material characteristics of the membrane were analyzed by scanning electron microscopy, Raman, UV-visible, and Fourier transform infrared analyses.

  1. Improved performance of lithium ion battery separator enabled by co-electrospinnig polyimide/poly(vinylidene fluoride-co-hexafluoropropylene) and the incorporation of TiO2-(2-hydroxyethyl methacrylate)

    Science.gov (United States)

    Chen, Weiya; Liu, Yanbo; Ma, Ying; Yang, Wenxiu

    2015-01-01

    Functionalized TiO2 (f-TiO2) was synthesized by the atom transfer radical polymerization process and then three types of composite nanofiber membranes including PI/PVdF-HFP (PI/PH, with no nanoparticles contained in PI), TiO2@PI/PVdF-HFP (T@PI/PH, with TiO2 mixed in PI) and f-TiO2@PI/PVdF-HFP (f-T@PI/PH, with f-TiO2 blended in PI) were prepared by bicomponent co-electrospinning technique which could separately maintain the original properties of both PVdF-HFP and PI nanofibers. UV-vis characterization manifested that the modified nanoparticles can provide significant improvements in reducing the particle agglomeration. Morphology, porosity, electrolyte uptake and liquid electrolyte contact angle of all the electrospun separators were investigated, and results showed that the composite separator with 2% f-TiO2 nanoparticle had smaller fiber diameter, higher porosity, larger electrolyte uptake, smaller contact angle and more excellent thermal dimensional stability. More importantly, the tensile strength of all the composite membranes increased by more than three times after thermal calendering process, which resulted from the several bonded points caused by the fusion of PVdF-HFP component with low melting temperature. Additionally, electrochemical properties of PI/PH, 2% T@PI/PH and 2% f-T@PI/PH composite separators and cycling performances of corresponding batteries were evaluated and 2% f-T@PI/PH composite separator showed better properties than the other two.

  2. A combination of CoO and Co nanoparticles supported on electrospun carbon nanofibers as highly stable air electrodes

    Science.gov (United States)

    Alegre, Cinthia; Busacca, Concetta; Di Blasi, Orazio; Antonucci, Vincenzo; Aricò, Antonino Salvatore; Di Blasi, Alessandra; Baglio, Vincenzo

    2017-10-01

    Bifunctional materials able to catalyze both the oxygen reduction (ORR) and the oxygen evolution (OER) reactions in alkaline media are still a challenge for the progress of energy conversion and storage devices such as metal-air batteries or unitized regenerative fuel cells. In this work, carbon nanofibers synthesized by electrospinning are modified with a combination of cobalt oxide and metallic cobalt (CoO-Co/CNF) and studied as a bifunctional air electrode for metal-air batteries. The performance of CoO-Co/CNF for both reactions is compared with state-of-the-art catalysts such as Pt/C and IrO2. The combination of cobalt oxide and metallic cobalt, finely distributed on the surface of graphitic carbon nanofibers, leads to a bifunctional catalyst with a half-wave potential for the ORR slightly better than Pt/C and a reversibility (ΔEOER-ORR) of 809 mV. The stability of CoO-Co/CNF is assessed by means of different stress tests: polarizations at high electrochemical potentials (2 V vs. RHE), rapid charge-discharge cycles at ±80 mA cm-2 and long durability tests by charging for 12 h at 60 mA cm-2 and discharging for 8 h at -80 mA cm-2. CoO-Co/CNF shows a remarkable stability, maintaining, at least, an 82% of its performance for the ORR after the stress tests, even when cycled for more than 100 h.

  3. Electrospun Polyaniline-Based Composite Nanofibers: Tuning the Electrical Conductivity by Tailoring the Structure of Thiol-Protected Metal Nanoparticles

    Directory of Open Access Journals (Sweden)

    Filippo Pierini

    2017-01-01

    Full Text Available Composite nanofibers made of a polyaniline-based polymer blend and different thiol-capped metal nanoparticles were prepared using ex situ synthesis and electrospinning technique. The effects of the nanoparticle composition and chemical structure on the electrical properties of the nanocomposites were investigated. This study confirmed that Brust’s procedure is an effective method for the synthesis of sub-10 nm silver, gold, and silver-gold alloy nanoparticles protected with different types of thiols. Electron microscopy results demonstrated that electrospinning is a valuable technique for the production of composite nanofibers with similar morphology and revealed that nanofillers are well-dispersed into the polymer matrix. X-ray diffraction tests proved the lack of a significant influence of the nanoparticle chemical structure on the polyaniline chain arrangement. However, the introduction of conductive nanofillers in the polymer matrix influences the charge transport noticeably improving electrical conductivity. The enhancement of electrical properties is mediated by the nanoparticle capping layer structure. The metal nanoparticle core composition is a key parameter, which exerted a significant influence on the conductivity of the nanocomposites. These results prove that the proposed method can be used to tune the electrical properties of nanocomposites.

  4. Asymmetric supercapacitors based on functional electrospun carbon nanofiber/manganese oxide electrodes with high power density and energy density

    Science.gov (United States)

    Lin, Sheng-Chi; Lu, Yi-Ting; Chien, Yu-An; Wang, Jeng-An; You, Ting-Hsuan; Wang, Yu-Sheng; Lin, Chih-Wen; Ma, Chen-Chi M.; Hu, Chi-Chang

    2017-09-01

    Carbon nanofibers modified with carboxyl groups (CNF-COOH) possessing good wettability and high porosity are homogeneously deposited with amorphous manganese dioxide (amorphous MnO2) by potentiodynamic deposition for asymmetric super-capacitors (ASCs). The potential-cycling in 1 M H2SO4 successfully enhances the hydrophilicity of carbonized polymer nanofibers and facilitates the access of electrolytes within the CNF-COOH matrix. This modification favors the deposition of amorphous MnO2 and improves its electrochemical utilization. In this composite, MnO2 homogeneously dispersed onto CNF-COOH provides desirable pseudocapacitance and the CNF-COOH network works as the electron conductor. The composite of CNF-COOH@MnO2-20 shows a high specific capacitance of 415 F g-1 at 5 mV s-1. The capacitance retention of this composite is 94% in a 10,000-cycle test. An ASC cell consisting of this composite and activated carbon as positive and negative electrodes can be reversibly charged/discharged to a cell voltage of 2.0 V in 1 M Na2SO4 and 4 mM NaHCO3 with specific energy and power of 36.7 Wh kg-1 and 354.9 W kg-1, respectively. This ASC also shows excellent cell capacitance retention (8% decay) in the 2V, 10,000-cycle stability test, revealing superior performance.

  5. Electrospun lignin-derived carbon nanofiber mats surface-decorated with MnO2 nanowhiskers as binder-free supercapacitor electrodes with high performance

    Science.gov (United States)

    Ma, Xiaojing; Kolla, Praveen; Zhao, Yong; Smirnova, Alevtina L.; Fong, Hao

    2016-09-01

    The aim of this study is to explore innovative materials for the development of next-generation supercapacitor electrodes. The hypothesis is that, upon the surface-decoration with appropriate amount of MnO2 nanowhiskers, freestanding and highly graphitic electrospun carbon nanofiber (ECNF) mats (with fiber diameters of ∼200 nm and BET specific surface areas of ∼583 m2 g-1) derived from a natural product of lignin would be binder-free supercapacitor electrodes with high performance. To test the hypothesis, the ECNF mats have been prepared first; thereafter, the acquired ECNF mats have been surface-decorated with varied amounts of MnO2 nanowhiskers to prepare three types of ECNF/MnO2 mats. The morphological and structural properties of ECNF and ECNF/MnO2 mats are characterized by SEM, TEM and XRD, the weight percentages of MnO2 nanowhiskers in three ECNF/MnO2 mats are determined by thermal gravimetric analysis; while the electrochemical performance of each mat/electrode is evaluated by cyclic voltammetry, galvanostatic charge/discharge method, and electrochemical impedance spectroscopy. This study reveals that, all of the three ECNF/MnO2 mats/electrodes have significantly enhanced electrochemical performances compared to the ECNF mat/electrode; while the ECNF/MnO2 (1:1) mat/electrode exhibits the highest gravimetric capacitance of 83.3 F g-1, energy density of 84.3 W h kg-1, and power density of 5.72 kW kg-1.

  6. Porous worm-like NiMoO4 coaxially decorated electrospun carbon nanofiber as binder-free electrodes for high performance supercapacitors and lithium-ion batteries

    Science.gov (United States)

    Tian, Xiaodong; Li, Xiao; Yang, Tao; Wang, Kai; Wang, Hongbao; Song, Yan; Liu, Zhanjun; Guo, Quangui

    2018-03-01

    The peculiar architectures consisting of electrospun carbon nanofibers coaxially decorated by porous worm-like NiMoO4 were successfully fabricated for the first time to address the poor cycling stability and inferior rate capability of the state-of-the-art NiMoO4-based electrodes caused by the insufficient structural stability, dense structure and low conductivity. The porous worm-like structure endows the electrode high capacitance/capacity due to large effective specific surface area and short electron/ion diffusion channels. Moreover, the robust integrated electrode with sufficient internal spaces can self-accommodate volume variation during charge/discharge processes, which is beneficial to the structural stability and integrity. By the virtue of rational design of the architecture, the hybrid electrode delivered high specific capacitance (1088.5 F g-1 at 1 A g-1), good rate capability (860.3 F g-1 at 20 A g-1) and long lifespan with a capacitance retention of 73.9% after 5000 cycles when used as supercapacitor electrode. For lithium-ion battery application, the electrode exhibited a high reversible capacity of 1132.1 mAh g-1 at 0.5 A g-1. Notably, 689.7 mAh g-1 can be achieved even after 150 continuous cycles at a current density of 1 A g-1. In the view of their outstanding electrochemical performance and the cost-effective fabrication process, the integrated nanostructure shows great promising applications in energy storage.

  7. One-dimensional Z-scheme TiO2/WO3/Pt heterostructures for enhanced hydrogen generation

    Science.gov (United States)

    Gao, Hongqing; Zhang, Peng; Hu, Junhua; Pan, Jimin; Fan, Jiajie; Shao, Guosheng

    2017-01-01

    One-dimensional Z-scheme TiO2/WO3/Pt heterostructures were fabricated by integrating a facile electrospinning technique and subsequent annealing in air. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and UV-vis diffuse reflectance spectroscopy, were used to characterize the as-fabricated samples. The results showed that the H2-generation of the as-fabricated one-dimensional Z-scheme TiO2/WO3/Pt heterostructures (S2) was greatly enhanced compared with pure TiO2 nanofibers (S0) and TiO2/WO3 nanofibers (S1). The enhanced photocatalyst activities were mainly attributed to the solid-state Z-scheme photosynthetic heterojunction system with Pt nanoparticle as an electron collector and WO3 as a hole collector, leading to effective charge separation on these semiconductors, which were evidenced by electrochemical impedance spectroscopy (EIS) and photocurrent analysis.

  8. Biocomposite scaffolds based on electrospun poly(3-hydroxybutyrate) nanofibers and electrosprayed hydroxyapatite nanoparticles for bone tissue engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Ramier, Julien [Institut de Chimie et des Matériaux Paris-Est, UMR 7182 CNRS, Université Paris-Est Créteil, 2, rue Henri Dunant, 94320 Thiais (France); Bouderlique, Thibault [Laboratoire “Croissance, Réparation et Régénération Tissulaires”, EAC 7149 CNRS, Université Paris-Est Créteil, 61, avenue du Général de Gaulle, 94010 Créteil (France); Stoilova, Olya; Manolova, Nevena; Rashkov, Iliya [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St., bl. 103A, BG-1113 Sofia (Bulgaria); Langlois, Valérie; Renard, Estelle [Institut de Chimie et des Matériaux Paris-Est, UMR 7182 CNRS, Université Paris-Est Créteil, 2, rue Henri Dunant, 94320 Thiais (France); Albanese, Patricia [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St., bl. 103A, BG-1113 Sofia (Bulgaria); Grande, Daniel, E-mail: grande@icmpe.cnrs.fr [Institut de Chimie et des Matériaux Paris-Est, UMR 7182 CNRS, Université Paris-Est Créteil, 2, rue Henri Dunant, 94320 Thiais (France)

    2014-05-01

    The electrospinning technique combined with the electrospraying process provides a straightforward and versatile approach for the fabrication of novel nanofibrous biocomposite scaffolds with structural, mechanical, and biological properties potentially suitable for bone tissue regeneration. In this comparative investigation, three types of poly(3-hydroxybutyrate) (PHB)-based scaffolds were engineered: (i) PHB mats by electrospinning of a PHB solution, (ii) mats of PHB/hydroxyapatite nanoparticle (nHA) blends by electrospinning of a mixed solution containing PHB and nHAs, and (iii) mats constituted of PHB nanofibers and nHAs by simultaneous electrospinning of a PHB solution and electrospraying of a nHA dispersion. Scaffolds based on PHB/nHA blends displayed improved mechanical properties compared to those of neat PHB mats, due to the incorporation of nHAs within the fibers. The electrospinning/electrospraying approach afforded biocomposite scaffolds with lower mechanical properties, due to their higher porosity, but they displayed slightly better biological properties. In the latter case, the bioceramic, i.e. nHAs, largely covered the fiber surface, thus allowing for a direct exposure to cells. The 21 day-monitoring through the use of MTS assays and SEM analyses demonstrated that human mesenchymal stromal cells (hMSCs) remained viable on PHB/nHA biocomposite scaffolds and proliferated continuously until reaching confluence. - Highlights: • Three different types of PHB-based scaffolds are engineered and thoroughly investigated. • The combination of electrospinning and electrospraying affords original nanofibrous biocomposite scaffolds. • PHB-based scaffolds show a strong capability of supporting viable cell development for 21 days.

  9. Fabrication of Conductive Polypyrrole Nanofibers by Electrospinning

    Directory of Open Access Journals (Sweden)

    Yiqun Cong

    2013-01-01

    Full Text Available Electrospinning is employed to prepare conductive polypyrrole nanofibers with uniform morphology and good mechanical strength. Soluble PPy was synthesized with NaDEHS as dopant and then applied to electrospinning with or without PEO as carrier. The PEO contents had great influence on the morphology and conductivity of the electrospun material. The results of these experiments will allow us to have a better understanding of PPy electrospun nanofibers and will permit the design of effective electrodes in the BMIs fields.

  10. Electrospun Borneol-PVP Nanocomposites

    Directory of Open Access Journals (Sweden)

    Xiao-Yan Li

    2012-01-01

    Full Text Available The present work investigates the validity of electrospun borneol-polyvinylpyrrolidone (PVP nanocomposites in enhancing drug dissolution rates and improving drug physical stability. Based on hydrogen bonding interactions and via an electrospinning process, borneol and PVP can form stable nanofiber-based composites. FESEM observations demonstrate that composite nanofibers with uniform structure could be generated with a high content of borneol up to 33.3% (w/w. Borneol is well distributed in the PVP matrix molecularly to form the amorphous composites, as verified by DSC and XRD results. The composites can both enhance the dissolution profiles of borneol and increase its physical stability against sublimation for long-time storage by immobilization of borneol molecules with PVP. The incorporation of borneol in the PVP matrix weakens the tensile properties of nanofibers, and the mechanism is discussed. Electrospun nanocomposites can be alternative candidates for developing novel nano-drug delivery systems with high performance.

  11. Sustained release of bactericidal concentrations of penicillin in the pleural space via an antibiotic-eluting pigtail catheter coated with electrospun nanofibers: results from in vivo and in vitro studies.

    Science.gov (United States)

    Chao, Yin-Kai; Lee, Cheng-Hung; Liu, Kuo-Sheng; Wang, Yi-Chuan; Wang, Chih-Wei; Liu, Shih-Jung

    2015-01-01

    Inadequate intrapleural drug concentrations caused by poor penetration of systemic antibiotics into the pleural cavity is a major cause of treatment failure in empyema. Herein, we describe a novel antibiotic-eluting pigtail catheter coated with electrospun nanofibers used for the sustained release of bactericidal concentrations of penicillin in the pleural space. Electrospun nanofibers prepared using polylactide-polyglycolide copolymer and penicillin G sodium dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol were used to coat the surface of an Fr6 pigtail catheter. The in vitro patterns of drug release were tested by placing the catheter in phosphate-buffered saline. In vivo studies were performed using rabbits treated with penicillin either intrapleurally (Group 1, 20 mg delivered through the catheter) or systemically (Group 2, intramuscular injection, 10 mg/kg). Penicillin concentrations in the serum and pleural fluid were then measured and compared. In vitro studies revealed a burst release of penicillin (10% of the total dose) occurring in the first 24 hours, followed by a sustained release in the subsequent 30 days. Intrapleural drug levels were significantly higher in Group 1 than in Group 2 (Ppenicillin concentrations remained above the minimum inhibitory concentration breakpoint throughout the entire study period. In contrast, serum penicillin levels were significantly higher in Group 2 than in Group 1 (P<0.001). Notably, all Group 2 rabbits showed signs of systemic toxicity (paralytic ileus and weight loss). We conclude that our antibiotic-eluting catheter may serve as a novel therapeutic option to treat empyema.

  12. One-Dimensional Nanostructured TiO2 for Photocatalytic Degradation of Organic Pollutants in Wastewater

    Directory of Open Access Journals (Sweden)

    Ting Feng

    2014-01-01

    Full Text Available The present paper reviews the progress in the synthesis of one-dimensional (1D TiO2 nanostructures and their environmental applications in the removal of organic pollutants. According to the shape, 1D TiO2 nanostructures can be divided into nanorods, nanotubes, nanowires/nanofibers, and nanobelts. Each of them can be synthesized via different technologies, such as sol-gel template method, chemical vapor deposition, and hydrothermal method. These methods are discussed in this paper, and the recent development of the synthesis technologies is also presented. Furthermore, the organic pollutants, degradation using the synthesized 1D TiO2 nanostructures is studied as an important application of photocatalytic oxidation (PCO. The 1D nanostructured TiO2 exhibited excellent photocatalytic activity in a PCO process, and the mechanism of photocatalytic degradation of organic pollutants is also discussed. Moreover, the modification of 1D TiO2 nanostructures using metal ions, metal oxide, or inorganic element can further enhance the photocatalytic activity of the photocatalyst. This phenomenon can be explained by the suppression of e−-h+ pairs recombination rate, increased specific surface area, and reduction of band gap. In addition, 1D nanostructured TiO2 can be further constructed as a film or membrane, which may extend its practical applications.

  13. Electrospun Fibers for Energy, Electronic, & Environmental Applications

    Science.gov (United States)

    Bedford, Nicholas M.

    Electrospinning is an established method for creating polymer and bio-polymer fibers of dimensions ranging from ˜10 nanometers to microns. The process typically involves applying a high voltage between a solution source (usually at the end of a capillary or syringe) and a substrate on which the nanofibers are deposited. The high electric field distorts the shape of the liquid droplet, creating a Taylor cone. Additional applied voltage ejects a liquid jet of the polymer solution in the Taylor cone toward the counter electrode. The formation of fibers is generated by the rapid electrostatic elongation and solvent evaporation of this viscoelastic jet, which typically generates an entangled non-woven mesh of fibers with a high surface area to volume ratio. Electrospinning is an attractive alternative to other processes for creating nano-scale fibers and high surface area to volume ratio surfaces due to its low start up cost, overall simplicity, wide range of processable materials, and the ability to generate a moderate amount of fibers in one step. It has also been demonstrated that coaxial electrospinning is possible, wherein the nanofiber has two distinct phases, one being the core and another being the sheath. This method is advantageous because properties of two materials can be combined into one fiber, while maintaining two distinct material phases. Materials that are inherently electrospinable could be made into fibers using this technique as well. The most common applications areas for electrospun fibers are in filtration and biomedical areas, with a comparatively small amount of work done in energy, environmental, and sensor applications. Furthermore, the use of biologically materials in electrospun fibers is an avenue of research that needs more exploration, given the unique properties these materials can exhibit. The research aim of this thesis is to explore the use of electrospun fibers for energy, electrical and environmental applications. For energy

  14. Increasing Mechanical Properties of 2-D-Structured Electrospun Nylon 6 Non-Woven Fiber Mats

    OpenAIRE

    Chunhui Xiang; Frey, Margaret W.

    2016-01-01

    Tensile strength, Young’s modulus, and toughness of electrospun nylon 6 non-woven fiber mats were improved by increasing individual nanofiber strength and fiber–fiber load sharing. Single-walled carbon nanotubes (CNTs) were used as reinforcement to increase the strength of the electrospun nylon 6 nanofibers. Young’s modulus, tensile strength, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % solutions increased 51%, 87%, and 136%, respectively, after incorporating 1 w...

  15. Composite nanofibers/water photosplitting and photocatalytic degradation of dairy effluent

    DEFF Research Database (Denmark)

    Kanjwal, Muzafar A.; Leung, Wallace W.F.; Chronakis, Ioannis S.

    2018-01-01

    Photocatalytic removal of Dairy effluent (DE) was studied by using TiO2-GeO2 and TiO2-CdO nanofibers (NFs), produced by electrospinning method. These NFs were characterized by SEM, TEM and XRD studies. The TiO2-GeO2 and TiO2-CdO NFs were smooth and continuous, with an average diameter of about 27...

  16. Reusable photocatalytic titanium dioxide-cellulose nanofiber films

    Science.gov (United States)

    Alexandra Snyder; Zhenyu Bo; Robert Moon; Jean-Christophe Rochet; Lia. Stanciu

    2013-01-01

    Titanium dioxide (TiO2) is a well-studied photocatalyst that is known to break down organic molecules upon ultraviolet (UV) irradiation. Cellulose nanofibers (CNFs) act as an attractive matrix material for the suspension of photocatalytic particles due to their desirable mechanical and optical properties. In this work, TiO2...

  17. Electrospinning of Nanofibers for Energy Applications

    OpenAIRE

    Guiru Sun; Liqun Sun; Haiming Xie; Jia Liu

    2016-01-01

    With global concerns about the shortage of fossil fuels and environmental issues, the development of efficient and clean energy storage devices has been drastically accelerated. Nanofibers are used widely for energy storage devices due to their high surface areas and porosities. Electrospinning is a versatile and efficient fabrication method for nanofibers. In this review, we mainly focus on the application of electrospun nanofibers on energy storage, such as lithium batteries, fuel cells, dy...

  18. Enhanced bone formation in electrospun poly(L-lactic-co-glycolic acid)–tussah silk fibroin ultrafine nanofiber scaffolds incorporated with graphene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Weili [Key Laboratory of Advanced Textile Composites (Ministry of Education), Institute of Textile Composites, Tianjin Polytechnic University, Tianjin 300387 (China); Henan Provincial Key Laboratory of Functional Textile Materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); He, Jianxin, E-mail: hejianxin771117@163.com [Henan Provincial Key Laboratory of Functional Textile Materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); Sang, Feng [Department of Acquired Immune Deficiency Syndrome Treatment and Research Center, The First Affiliated Hospital of Henan University of Traditional Chinese Medicine, Zhengzhou 450000 (China); Wang, Qian [Henan Provincial Key Laboratory of Functional Textile Materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); Chen, Li [Key Laboratory of Advanced Textile Composites (Ministry of Education), Institute of Textile Composites, Tianjin Polytechnic University, Tianjin 300387 (China); Cui, Shizhong [Key Laboratory of Advanced Textile Composites (Ministry of Education), Institute of Textile Composites, Tianjin Polytechnic University, Tianjin 300387 (China); Henan Provincial Key Laboratory of Functional Textile Materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); Ding, Bin [Henan Provincial Key Laboratory of Functional Textile Materials, Zhongyuan University of Technology, Zhengzhou 450007 (China); State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201600 (China)

    2016-05-01

    To engineer bone tissue, it is necessary to provide a biocompatible, mechanically robust scaffold. In this study, we fabricated an ultrafine nanofiber scaffold by electrospinning a blend of poly(L-lactic-co-glycolic acid), tussah silk fibroin, and graphene oxide (GO) and characterized its morphology, biocompatibility, mechanical properties, and biological activity. The data indicate that incorporation of 10 wt.% tussah silk and 1 wt.% graphene oxide into poly(L-lactic-co-glycolic acid) nanofibers significantly decreased the fiber diameter from 280 to 130 nm. Furthermore, tussah silk and graphene oxide boosted the Young's modulus and tensile strength by nearly 4-fold and 3-fold, respectively, and significantly enhanced adhesion, proliferation in mouse mesenchymal stem cells and functionally promoted biomineralization-relevant alkaline phosphatase (ALP) and mineral deposition. The results indicate that composite nanofibers could be excellent and versatile scaffolds for bone tissue engineering. - Highlights: • GO-doped PLGA–tussah silk fibroin ultrafine nanofibers with diameter of about 130 nm were fabricated by electrospinning. • Incorporation of 10 wt.% tussah silk to the PLGA nanofibers accelerates osteoblast differentiation and formation of new bone. • Mechanical properties of composite nanofiber mats had been significantly improved after embedding with GO nanosheets. • Nanostructured composite scaffolds effectively accelerate mesenchymal stem cells differentiation and formation of new bone.

  19. Study on particulates and volatile organic compounds removal with TiO2 nonwoven filter prepared by electrospinning.

    Science.gov (United States)

    Hong, Gui-Bing; Chang, Chang-Tang

    2014-06-01

    In this study, polyvinyl alcohol (PVA) and titania (TiO2) Degussa P-25 were mixed to generate TiO2 nonwoven filters using electrospinning. The wires of titanium dioxide and the nonwoven binding titania nanofibers were formed using 14 kV voltage and a distance of 15 cm. A single-factor experimental method was used to investigate the effects of parameters such as initial concentration, retention time, and light source on acetone removal by nonwoven binding titania nanofibers. Furthermore, the effects of parameters such as gas pressure, particle size, initial concentration, and retention time on the removal of particulates were also assessed. The results showed that the degradation efficiency increased with decreasing initial concentrations and increasing retention time. The best operational conditions during this study for the removal of acetone using the TiO2 nonwoven filters were a retention time of 100 sec, initial acetone concentration of 250 ppm, and ultraviolet (UV) light source of 254 nm. Under those conditions, 99% acetone removal efficiency was obtained. In addition, 90% particulate matter removal efficiency was reached when the particulate size was greater than 200 nm and the reaction time was longer than 5 minutes. The prepared TiO2/nanofiber has good performance for volatile organic compounds (VOCs) and particulate removal at the same time. In this study, polyvinyl alcohol (PVA) and titania (TiO2) Degussa P-25 were mixed to generate TiO2 nonwoven filters using electrospinning. The results showed that the optimum operating conditions for the removal of acetone using the TiO2 nonwoven filters were a retention time of 100 sec, initial acetone concentration of 250 ppm, and UV light source of 254 nm. Under those conditions, 99% acetone removal efficiency was obtained.

  20. Recent developments in electrospinning of nanofiber yarns.

    Science.gov (United States)

    Shuakat, Muhammad Nadeem; Lin, Tong

    2014-02-01

    Nanofibers possess high surface area and excellent porosity. Though nanofibers can be produced by a variety of techniques, electrospinning stands distinct because of its simplicity and flexibility in processing different polymer materials, and ability to control fiber diameter, morphology, orientation, and chemical component. Nonetheless, electrospun nanofibers are predominantly produced in the form of randomly oriented fiber webs, which restrict their wide use. Converting nanofibers into twisted continuous bundles, i.e., nanofiber yarns, can improve their strength and facilitate their subsequent processes, but remains challenging to make. Nanofiber yarns also create enormous opportunities to develop well-defined three-dimensional nanofibrous architectures. This review article gives an overview of the state-of-the-art techniques for electrospinning of nanofiber yarns and control of nanofiber alignment. A detailed account on techniques to produce twisted/non-twisted short bundles and continuous yarns are discussed.

  1. Biomimetic electrospun nanofibrous structures for tissue engineering

    OpenAIRE

    Wang, Xianfeng; Ding, Bin; Li, Bingyun

    2013-01-01

    Biomimetic nanofibrous scaffolds mimicking important features of the native extracellular matrix provide a promising strategy to restore functions or achieve favorable responses for tissue regeneration. This review provides a brief overview of current state-of-the-art research designing and using biomimetic electrospun nanofibers as scaffolds for tissue engineering. It begins with a brief introduction of electrospinning and nanofibers, with a focus on issues related to the biomimetic design a...

  2. A facile fabrication of nitrogen-doped electrospun In{sub 2}O{sub 3} nanofibers with improved visible-light photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Na; Shao, Changlu, E-mail: clshao@nenu.edu.cn; Li, Xinghua, E-mail: lixh781@nenu.edu.cn; Miao, Fujun; Wang, Kexin; Liu, Yichun

    2017-01-01

    Highlights: • N-doped In{sub 2}O{sub 3} nanofibers are facilely fabricated by gaseous ammonia treatment. • Adjusting the annealing temperature leads to different N-doped In{sub 2}O{sub 3} nanofibers. • Nitrogen doping was found to be interstitial mode. • N-In{sub 2}O{sub 3} exhibited effective charge carrier separation and photocatalytic activity. • The photocatalysts can be easily separated from the reaction system. - Abstract: Semiconductor photocatalysis demonstrates to be an effective approach for eliminating most types of environment contaminants and for producing hydrogen. Herein, a facile synthesis route combining electrospinning technique and thermal treatment method under NH{sub 3} atmosphere has been presented as a straightforward protocol for the fabrication of nitrogen-doped In{sub 2}O{sub 3} (N-In{sub 2}O{sub 3}) nanofibers, the nitrogen content of which can be well controlled by adjusting the annealing temperature. Photocatalytic tests show that the N-In{sub 2}O{sub 3} nanofibers demonstrate an improved degradation rate of Rhodamine B (RB) compared with pure In{sub 2}O{sub 3} nanofibers under visible-light irradiation. This can be attributed to the nitrogen atom introducing at interstitial sites as well as the generation of oxygen vacancy on the surface of In{sub 2}O{sub 3} nanofibers, resulting in the enhanced utilization of visible light for the N-In{sub 2}O{sub 3} nanofibers. Furthermore, the obtained N-In{sub 2}O{sub 3} nanofibers with the advantage of ultra-long one-dimensional nanostructures can be recycled several times by facile sedimentation and hence present almost no decrease in photocatalytic activity indicative of a well regeneration capability. Therefore, the as-fabricated nitrogen-doped In{sub 2}O{sub 3} nanofibers as a promising photocatalyst present good photocatalytic degradation of organic pollutant in waste water for practical application.

  3. Preparation of PVA/TiO2 Composites Nanofibers by using Electrospinning Method for Photocatalytic Degradation

    Science.gov (United States)

    Nasikhudin; Ismaya, E. P.; Diantoro, M.; Kusumaatmaja, A.; Triyana, K.

    2017-05-01

    PVA/TiO2 composites nanofibers have been prepared by using electrospinning method. Electrospinning was performed at a voltage of 15 kV, with a tip-collector distance of 14 cm. The PVA/TiO2 composites nanofibers were characterized by FTIR, SEM, and EDAX. The results showed that PVA/TiO2 composites nanofibers were successfully formed. SEM observation showed that the nanofibers has several hundred nanometers with a smooth surface and have TiO2 nanoparticle distributed in the nanofibers. FTIR result shows a functional group of PVA and EDAX result demonstrates the presence of TiO2 in the nanofibers. The photocatalytic activity of PVA/TiO2 composites nanofibers were investigated for the degradation of methylene blue under UV light. The PVA/TiO2 composite nanofibers suspending in the dye solution have dye removal of 70% dye was degraded in 5 h. As a comparison, the TiO2 powder that has dye removal of 95% dye was degraded in 5 h. Photocatalytic activity of PVA/TiO2 nanofiber was lower than TiO2 powder, but PVA/TiO2 nanofiber was more efficient than TiO2 powder regarding process treatments photocatalytic.

  4. Piezoelectric properties of electrospun nanofibers of BaTiO3; Propiedades piezoeletricas de nanofibras eletrofiadas de BaTiO3

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, L.F.R.M.; Melo, G.F.; Goncalves, A.M.; Eiras, J.A.; Bretas, R.E.S., E-mail: bretas@ufscar.br [Universidade Federal de Sao Carlos (UFSCar), SP (Brazil)

    2016-07-01

    BaTiO3 nanofibers were produced by the electrospinning method from a mixture of a solution of the precursors Ba (CH{sub 3}COO){sub 2} and [(CH{sub 3}){sub 2}CHO]{sub 4}Ti in acetic acid and a solution of poly(vinylpyrrolidone) in ethanol. A voltage of 10 kV and a working distance of 4.6 cm were used for the electrospinning, at controlled room temperature and humidity of 21 °C and 60% respectively. Nanofibers as spun were dried in air on an air-circulating oven at 100 °C for one hour to remove residual solvent and were subsequently calcined at 750 °C during 2 h. The morphology, crystallographic structure and piezoelectric properties of the nanofibers were analyzed by scanning electron microscopy (SEM), X-ray angle (WAXS) and Piezoresponse Force Microscopy (PFM), respectively. The average diameter of the nanofibers was 414 nm with an aspect ratio of 40. By PFM, there was strong evidence that the nanofibers had piezoelectric activity. (author)

  5. Enhanced bone formation in electrospun poly(L-lactic-co-glycolic acid)-tussah silk fibroin ultrafine nanofiber scaffolds incorporated with graphene oxide.

    Science.gov (United States)

    Shao, Weili; He, Jianxin; Sang, Feng; Wang, Qian; Chen, Li; Cui, Shizhong; Ding, Bin

    2016-05-01

    To engineer bone tissue, it is necessary to provide a biocompatible, mechanically robust scaffold. In this study, we fabricated an ultrafine nanofiber scaffold by electrospinning a blend of poly(L-lactic-co-glycolic acid), tussah silk fibroin, and graphene oxide (GO) and characterized its morphology, biocompatibility, mechanical properties, and biological activity. The data indicate that incorporation of 10 wt.% tussah silk and 1 wt.% graphene oxide into poly(L-lactic-co-glycolic acid) nanofibers significantly decreased the fiber diameter from 280 to 130 nm. Furthermore, tussah silk and graphene oxide boosted the Young's modulus and tensile strength by nearly 4-fold and 3-fold, respectively, and significantly enhanced adhesion, proliferation in mouse mesenchymal stem cells and functionally promoted biomineralization-relevant alkaline phosphatase (ALP) and mineral deposition. The results indicate that composite nanofibers could be excellent and versatile scaffolds for bone tissue engineering. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. A Simple Method for the Preparation of TiO2 /Ag-AgCl@Polypyrrole Composite and Its Enhanced Visible-Light Photocatalytic Activity.

    Science.gov (United States)

    Yao, Tongjie; Shi, Lei; Wang, Hao; Wang, Fangxiao; Wu, Jie; Zhang, Xiao; Sun, Jianmin; Cui, Tieyu

    2016-01-01

    A novel and facile method was developed to prepare a visible-light driven TiO2 /Ag-AgCl@polypyrrole (PPy) photocatalyst with Ag-AgCl nanoparticles supported on TiO2 nanofibers and covered by a thin PPy shell. During the synthesis, the PPy shell and Ag-AgCl nanoparticles were prepared simultaneously onto TiO2 nanofibers, which simplified the preparation procedure. In addition, because Ag-AgCl aggregates were fabricated via partly etching the Ag nanoparticles, their size was well controlled at the nanoscale, which was beneficial for improvement of the contact surface area. Compared with reference photocatalysts, the TiO2 /Ag-AgCl@PPy composite exhibited an enhanced photodegradation activity towards rhodamine B under visible-light irradiation. The superior photocatalytic property originated from synergistic effects between TiO2 nanofibers, Ag-AgCl nanoparticles and the PPy shell. Furthermore, the TiO2 /Ag-AgCl@PPy composite could be easily separated and recycled without obvious reduction in activity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Electrospun NiO, ZnO and composite NiO–ZnO nanofibers/photocatalytic degradation of dairy effluent

    DEFF Research Database (Denmark)

    Kanjwal, Muzafar Ahmad; Chronakis, Ioannis S.; Barakat, Nasser A.M.

    2015-01-01

    Among the food wastes, the dairy effluent (DE) is considered to be the most polluting one because of the large volume of wastewater generated and its high organic load. Photocatalytic degradation of DE and organic dye methylene blue (MB) was studied using Zinc oxide nanofibers (ZnO NFs), Nickel...... even after calcination of 600°C and more than 3h of photocatalytic degradation of DE and MB dye. The ZnO NFs and NiO NFs were effective materials for degradation of DE and MB dye. NiO NFs and ZnO NFs showed a maximum degradation of 70% and 75% in DE and 50% and 60% in MB dye respectively, after 3h...... oxide nanofibers (NiO NFs) and composite Zinc oxide–Nickel oxide nanofibers (ZnO–NiO NFs). These nanomembranes were characterized in SEM, TEM, XRD and UV studies. The pristine nanofiber membranes were smooth and continuous, with an average diameter of about 400nm, and held their nanofibrous morphology...

  8. Development of mats composed by TiO{sub 2} and carbon dual electrospun nanofibers: A possible anode material in microbial fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Gomez, Nora A.; Balderas-Renteria, Isaias [Universidad Autónoma de Nuevo León, Facultad de Ciencias Químicas, Av. Universidad S/N Cd. Universitaria San Nicolás de los Garza Nuevo León, C.P. 66451 México (Mexico); Garcia-Gutierrez, Domingo I. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, Av. Universidad S/N Cd. Universitaria San Nicolás de los Garza Nuevo León, C.P. 66451 México (Mexico); Universidad Autónoma de Nuevo León, Centro de Innovación, Investigación y Desarrollo en Ingeniería y Tecnología, PIIT, Av. Universidad S/N Cd. Universitaria San Nicolás de los Garza Nuevo León, C.P. 66451 México (Mexico); Mosqueda, Hugo A. [Universidad Autónoma de Nuevo León, Facultad de Ingeniería Mecánica y Eléctrica, Av. Universidad S/N Cd. Universitaria San Nicolás de los Garza Nuevo León, C.P. 66451 México (Mexico); and others

    2015-03-15

    Highlights: • Dual nanofiber of TiO{sub 2}–C/C showed excellent electrical performance. • TiO{sub 2}–C/C dual nanofiber can host a dense biofilm of electroactivated Escherichia coli. • Dual nanofibers can be applied as anode to obtain electricity in microbial fuel cells. - Abstract: A new material based on TiO{sub 2(rutile)}–C{sub (semi-graphitic)}/C{sub (semi-graphitic)} dual nanofiber mats is presented, whose composition and synthesis methodology are fundamental factors for the development of exoelectrogenic biofilms on its surface. Therefore, this material shows the required characteristics for possible applications in the bioconversion process of an organic substrate to electricity in a microbial fuel cell. Chronoamperometry, cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and electrical conductivity analyses showed excellent electrical performance of the material for the application intended; a resistance as low as 3.149 Ω was able to be measured on this material. Furthermore, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies confirmed the morphology sought on the material for the application intended, dual nanofibres TiO{sub 2(rutile)}–C{sub (semi-graphitic)}/C{sub (semi-graphitic)} with a side by side configuration. The difference in composition of the fibers forming the dual nanofibers was clearly observed and confirmed by energy dispersive X-ray spectroscopy (EDXS), and their crystal structure was evident in the results obtained from selected area electron diffraction (SAED) studies. This nanostructured material presented a high surface area and is biocompatible, given that it can host a dense biofilm of electroactivated Escherichia coli. In this study, the maximum current density obtained in a half microbial fuel cell was 8 A/m{sup 2} (0.8 mA/cm{sup 2})

  9. A fabricated electro-spun sensor based on Lake Red C pigments doped into PAN (polyacrylonitrile) nano-fibers for electrochemical detection of Aflatoxin B1 in poultry feed and serum samples.

    Science.gov (United States)

    Babakhanian, Arash; Momeneh, Tahereh; Aberoomand-azar, Parviz; Kaki, Samineh; Torki, Mehran; Hossein Kiaie, Seyed; Sadeghi, Ehsan; Dabirian, Farzad

    2015-11-21

    The aim of this work was to fabricate a novel nano-fiber modified electrode, involving Lake Red C (LRC) pigments doped into electrospun polyacrylonitrile (PAN) fibrous films. Cyclic voltammetry (CV), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and differential pulse voltammetry (DPV) techniques were used for electrochemical and morphological characterization of the composite fibers. This sensor responds to Aflatoxin B1 (AFB1) over the concentration range of 40-120 nM with high accuracy and precision in analysis. The modified electrode exhibited an excellent electrocatalytic ability (α = 0.42, log K(s) = 4.21 s(-1), and Γ = 1.49 × 10(-5) mmol cm(-2)) for reduction of AFB1 at the optimum pH of 6 and working potential of -0.75 V (vs. SCE). The common substances accompanying AFB1 had no serious interferences on the response of the modified electrode to AFB1. The modified electrode indicated reproducible behavior and a high level stability during the experiments, making it particularly suitable for the analytical determination of AFB1 in poultry feed and serum samples.

  10. Discovery of the beta-form crystal structure in electrospun nanofibers of bio-based poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] and its implication on properties

    Science.gov (United States)

    Gong, Liang

    Bacterially produced poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] (PHBHx) is a new type of bioplastic which not only inherits the excellent biodegradability and biocompatibility of its parent homopolymer, polyhydroxybutyrate (PHB), but also overcomes PHB’s brittleness and stiffness with the incorporation of 3-hydroxyhexanoate (Hx) comonomer units with medium-chain-length (mcl) side chains. The tough and ductile PHBHx, with a much lower crystallinity and melting temperature, is well-suited for many practical applications. Efforts have been made to broaden the application range of PHBHx by introducing the beta-form crystalline structure, where the molecular chains adopt a planar zig-zag conformation. However, it is extremely difficult to produce this beta-form in PHBHx due to its much lower crystallinity and much more flexible molecular chains. In this study, we report an approach using the technique of electrospinning. The strain-induced metastable β-form crystalline structure was successfully introduced in PHBHx by collecting the macroscopically aligned electrospun PHBHx nanofibers across the air gap on a piece of aluminum foil and on the tapered edge of a high-speed rotary disk. The presence of the β-form crystal structure in electrospun fiber mats was confirmed by wide-angle X-ray diffraction (WAXD) and Fourier transform infrared spectroscopy (FTIR), with molecular orientation of the polymer chains along the fiber axis revealed by polarized FTIR. Selected area electron diffraction (SAED) and AFM-IR were utilized to investigate the morphological and structural details of individual PHBHx nanofibers. The results demonstrated a coexistence of the thermodynamically stable α-form crystalline structure, where molecular chains adopt a left-handed 21 helical conformation, and the β-form in single fibers. The molecular orientation level and the relative amounts of the two crystalline polymorphs were found to be highly dependent on fiber collection methods

  11. Biologically Inspired Nanofibers for Use in Translational Bioanalytical Systems

    Science.gov (United States)

    Matlock-Colangelo, Lauren; Baeumner, Antje J.

    2014-06-01

    Electrospun nanofiber mats are characterized by large surface-area-to-volume ratios, high porosities, and a diverse range of chemical functionalities. Although electrospun nanofibers have been used successfully to increase the immobilization efficiency of biorecognition elements and improve the sensitivity of biosensors, the full potential of nanofiber-based biosensing has not yet been realized. Therefore, this review presents novel electrospun nanofiber chemistries developed in fields such as tissue engineering and drug delivery that have direct application within the field of biosensing. Specifically, this review focuses on fibers that directly encapsulate biological additives that serve as immobilization matrices for biological species and that are used to create biomimetic scaffolds. Biosensors that incorporate these nanofibers are presented, along with potential future biosensing applications such as the development of cell culture and in vivo sensors.

  12. Cell proliferation on PVA/sodium alginate and PVA/poly(γ-glutamic acid) electrospun fiber

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jen Ming, E-mail: jmyang@mail.cgu.edu.tw [Department of Chemical and Materials Engineering, Chang Gung University, Taoyuan 333, Taiwan, ROC (China); Yang, Jhe Hao [Department of Electronic Engineering, Chang Gung University, Taoyuan, Taiwan, ROC (China); Tsou, Shu Chun; Ding, Chian Hua [Department of Chemical and Materials Engineering, Chang Gung University, Taoyuan 333, Taiwan, ROC (China); Hsu, Chih Chin [Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital at Keelung, Keelung, Taiwan, ROC (China); School of Traditional Chinese Medicine, Chang Gung University, Taoyuan, Taiwan, ROC (China); Yang, Kai Chiang [School of Biomedical Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei 11031, Taiwan, ROC (China); Yang, Chun Chen [Department of Chemical Engineering, Ming-Chi University of Science and Technology, New Taipei City, Taiwan, ROC (China); Chen, Ko Shao [Department of Materials Engineering, Tatung University, Taipei, Taiwan, ROC (China); Chen, Szi Wen [Department of Electronic Engineering, Chang Gung University, Taoyuan, Taiwan, ROC (China); Wang, Jong Shyan [Department of Physical Therapy and the Graduate Institute of Rehabilitation Science, Chang Gung University, Taoyuan, Taiwan, ROC (China)

    2016-09-01

    To overcome the obstacles of easy dissolution of PVA nanofibers without crosslinking treatment and the poor electrospinnability of the PVA cross-linked nanofibers via electrospinning process, the PVA based electrospun hydrogel nanofibers are prepared with post-crosslinking method. To expect the electrospun hydrogel fibers might be a promising scaffold for cell culture and tissue engineering applications, the evaluation of cell proliferation on the post-crosslinking electrospun fibers is conducted in this study. At beginning, poly(vinyl alcohol) (PVA), PVA/sodium alginate (PVASA) and PVA/poly(γ-glutamic acid) (PVAPGA) electrospun fibers were prepared by electrospinning method. The electrospun PVA, PVASA and PVAPGA nanofibers were treated with post-cross-linking method with glutaraldehyde (Glu) as crosslinking agent. These electrospun fibers were characterized with thermogravimetry analysis (TGA) and their morphologies were observed with a scanning electron microscope (SEM). To support the evaluation and explanation of cell growth on the fiber, the study of 3T3 mouse fibroblast cell growth on the surface of pure PVA, SA, and PGA thin films is conducted. The proliferation of 3T3 on the electrospun fiber surface of PVA, PVASA, and PVAPGA was evaluated by seeding 3T3 fibroblast cells on these crosslinked electrospun fibers. The cell viability on electrospun fibers was conducted with water-soluble tetrazolium salt-1 assay (Cell Proliferation Reagent WST-1). The morphology of the cells on the fibers was also observed with SEM. The results of WST-1 assay revealed that 3T3 cells cultured on different electrospun fibers had similar viability, and the cell viability increased with time for all electrospun fibers. From the morphology of the cells on electrospun fibers, it is found that 3T3 cells attached on all electrospun fiber after 1 day seeded. Cell–cell communication was noticed on day 3 for all electrospun fibers. Extracellular matrix (ECM) productions were found and

  13. Implication of nanofibers in oral drug delivery.

    Science.gov (United States)

    Kapahi, Himani; Khan, Nikhat Mansoor; Bhardwaj, Ankur; Mishra, Neeraj

    2015-01-01

    Nanofibers has gained significant prominence in recent years due to its wide applications in medicinal pharmacy, textile, tissue engineering and in various drug delivery system. In oral drug delivery system (DDS), nanofibers can be delivered as Nanofiber scaffolds, electrosponge nanofibers as oral fast delivery system, multilayered nanofiber loaded mashes, surface modified cross-linked electrospun nanofibers. Nanofibers are of 50- 1000 nm size fibres having large surface area, high porosity, small pore size, low density. Various approaches for formulation of nanofibers are molecular assembly, thermally induced phase separation, electrospining. Most commonly used by using electrospining polymer nanofibres with different range can be produced collective usage of electro spinning with pharmaceutical polymers offers novel tactics for developing drug delivery system (DDS). Different polymers used in preparation of nanofibers include biodegradable hydrophilic polymers, hydrophobic polymers and amphiphilic polymers. Electrospun nanofibers are often used to load insoluble drugs for enhancing their dissolution properties due to their high surface area per unit mass. Besides the water insoluble drugs freely water soluble sodium can also spun into the fibers. The most commonly polymers used for nanofibers are gelatin, dextran, nylon, polystyrene, polyacrylonitrile, polycarbonate, polyimides, poly vinyl alchol, polybenzimidazole. Delivery systems reviewed rely on temporal control, changes in pH along the GIT, the action of local enzymes to trigger drug release, and changes in intraluminal pressure. Dissolution of enteric polymer coatings due to a change in local pH and reduction of azo-bonds to release an active agent are both used in commercially marketed products. In vitro and in vivo studies have demonstrated that the release rates of drugs from these nanofiber formulations are enhanced compared to those from original drug substance. This review is focused on the different

  14. Physical and Chemical Properties of Pan-Derived Electrospun Activated Carbon Nanofibers and Their Potential for Use As An Adsorbent for Toxic Industrial Chemicals (Postprint)

    Science.gov (United States)

    2012-09-14

    carbon fiber cloth (ACFC) and Calgon BPL™ granular activated carbon (GAC) 2 Methods 2.1 Precursor selection and nonwoven nanofiber material preparation...respirators, re- generative filter systems that can protect against TICs, or perhaps smaller and more energy-efficient pressure-swing- adsorption systems...Peterson, G.W., Karwacki, C.: Novel collective protection filters for emerging TIC requirements: axial- and radial-flow filter de- signs. Edgewood Chemical

  15. Electrospun polystyrene/graphene nanofiber film as a novel adsorbent of thin film microextraction for extraction of aldehydes in human exhaled breath condensates.

    Science.gov (United States)

    Huang, Jing; Deng, Hongtao; Song, Dandan; Xu, Hui

    2015-06-09

    In the current study, we introduced a novel polystyrene/graphene (PS/G) composite nanofiber film for thin film microextraction (TFME) for the first time. The PS/G nanofiber film was fabricated on the surface of filter paper by a facile electrospinning method. The morphology and extraction performance of the resultant composite film were investigated systematically. The PS/G nanofiber film exhibited porous fibrous structure, large surface area and strong hydrophobicity. A new thin film microextraction-high performance liquid chromatography (TFME-HPLC) method was developed for the determination of six aldehydes in human exhaled breath condensates. The method showed high enrichment efficiency and fast analysis speed. Under the optimal conditions, the linear ranges of the analytes were in the range of 0.02-30 μmol L(-1) with correlation coefficients above 0.9938, and the recoveries were between 79.8% and 105.6% with the relative standard deviation values lower than 16.3% (n=5). The limits of quantification of six aldehydes ranged from 13.8 to 64.6 nmol L(-1). The established method was successfully applied for the quantification of aldehyde metabolites in exhaled breath condensates of lung cancer patients and healthy people. Taken together, the TFME-HPLC method provides a simple, rapid, sensitive, cost-effective, non-invasion approach for the analysis of linear aliphatic aldehydes in human exhaled breath condensates. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Paraffin embedding allows effective analysis of proliferation, survival, and immunophenotyping of cells cultured on poly(l-lactic acid) electrospun nanofiber scaffolds.

    Science.gov (United States)

    Foroni, Laura; Dirani, Giorgio; Gualandi, Chiara; Focarete, Maria Letizia; Pasquinelli, Gianandrea

    2010-08-01

    Morphological and immunophenotypic characterization of cells grown on poly(l-lactic acid) (PLLA) electrospun scaffolds is usually performed using immunofluorescence and cryosections. However, these methods present practical limits; histological processing, on the other hand, is believed to lead to artifactual changes in the scaffold structure. Here the formalin-fixed paraffin-embedding (FFPE) procedure was tailored to process PLLA electrospun scaffolds grown with human umbilical vein endothelial cells. After 1 to 7 days of culture, the scaffolds were processed with the FFPE procedure. Using this protocol, not only cross sections but also "en face" sections were obtained. This made possible to perform the effective light microscopy analysis of cell morphology and to assess cell adhesion and penetration without considerable scaffold damage. The method was also suitable for immunohistochemical assays, such as proliferation (Ki67), extracellular matrix production (type IV collagen), survival (cleaved caspase-3), and immunophenotyping (KDR, CD44, vimentin, CD45); results were compared with those obtained using complementary techniques (scanning electron microscopy, Alamar Blue assay, and cryosections). The FFPE protocol can be safely applied to PLLA scaffolds and provides information that are essential to study the mechanisms of interaction between cells and PLLA fibers before their potential implantation in vivo.

  17. Biofunctionalized nanofibers using Arthrospira (Spirulina) biomass and biopolymer.

    Science.gov (United States)

    de Morais, Michele Greque; Stillings, Christopher; Dersch, Roland; Rudisile, Markus; Pranke, Patrícia; Costa, Jorge Alberto Vieira; Wendorff, Joachim

    2015-01-01

    Electrospun nanofibers composed of polymers have been extensively researched because of their scientific and technical applications. Commercially available polyhydroxybutyrate (PHB) and polyhydroxybutyrate-co-valerate (PHB-HV) copolymers are good choices for such nanofibers. We used a highly integrated method, by adjusting the properties of the spinning solutions, where the cyanophyte Arthrospira (formally Spirulina) was the single source for nanofiber biofunctionalization. We investigated nanofibers using PHB extracted from Spirulina and the bacteria Cupriavidus necator and compared the nanofibers to those made from commercially available PHB and PHB-HV. Our study assessed nanofiber formation and their selected thermal, mechanical, and optical properties. We found that nanofibers produced from Spirulina PHB and biofunctionalized with Spirulina biomass exhibited properties which were equal to or better than nanofibers made with commercially available PHB or PHB-HV. Our methodology is highly promising for nanofiber production and biofunctionalization and can be used in many industrial and life science applications.

  18. Biofunctionalized Nanofibers Using Arthrospira (Spirulina Biomass and Biopolymer

    Directory of Open Access Journals (Sweden)

    Michele Greque de Morais

    2015-01-01

    Full Text Available Electrospun nanofibers composed of polymers have been extensively researched because of their scientific and technical applications. Commercially available polyhydroxybutyrate (PHB and polyhydroxybutyrate-co-valerate (PHB-HV copolymers are good choices for such nanofibers. We used a highly integrated method, by adjusting the properties of the spinning solutions, where the cyanophyte Arthrospira (formally Spirulina was the single source for nanofiber biofunctionalization. We investigated nanofibers using PHB extracted from Spirulina and the bacteria Cupriavidus necator and compared the nanofibers to those made from commercially available PHB and PHB-HV. Our study assessed nanofiber formation and their selected thermal, mechanical, and optical properties. We found that nanofibers produced from Spirulina PHB and biofunctionalized with Spirulina biomass exhibited properties which were equal to or better than nanofibers made with commercially available PHB or PHB-HV. Our methodology is highly promising for nanofiber production and biofunctionalization and can be used in many industrial and life science applications.

  19. Encapsulation of gallic acid/cyclodextrin inclusion complex in electrospun polylactic acid nanofibers: Release behavior and antioxidant activity of gallic acid.

    Science.gov (United States)

    Aytac, Zeynep; Kusku, Semran Ipek; Durgun, Engin; Uyar, Tamer

    2016-06-01

    Cyclodextrin-inclusion complexes (CD-ICs) possess great prominence in food and pharmaceutical industries due to their enhanced ability for stabilization of active compounds during processing, storage and usage. Here, CD-IC of gallic acid (GA) with hydroxypropyl-beta-cyclodextrin (GA/HPβCD-IC) was prepared and then incorporated into polylactic acid (PLA) nanofibers (PLA/GA/HPβCD-IC-NF) using electrospinning technique to observe the effect of CD-ICs in the release behavior of GA into three different mediums (water, 10% ethanol and 95% ethanol). The GA incorporated PLA nanofibers (PLA/GA-NFs) were served as control. Phase solubility studies showed an enhanced solubility of GA with increasing amount of HPβCD. The detailed characterization techniques (XRD, TGA and (1)H-NMR) confirmed the formation of inclusion complex between GA and HPβCD. Computational modeling studies indicated that the GA made an efficient complex with HPβCD at 1:1 either in vacuum or aqueous system. SEM images revealed the bead-free and uniform morphology of PLA/GA/HPβCD-IC-NF. The release studies of GA from PLA/GA/HPβCD-IC-NF and PLA/GA-NF were carried out in water, 10% ethanol and 95% ethanol, and the findings revealed that PLA/GA/HPβCD-IC-NF has released much more amount of GA in water and 10% ethanol system when compared to PLA/GA-NF. In addition, GA was released slowly from PLA/GA/HPβCD-IC-NF into 95% ethanol when compared to PLA/GA-NF. It was also observed that electrospinning process had no negative effect on the antioxidant activity of GA when GA was incorporated in PLA nanofibers. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Synthesis of double-shelled sea urchin-like yolk-shell Fe3O4/TiO2/Au microspheres and their catalytic applications

    Science.gov (United States)

    Li, Jie; Tan, Li; Wang, Ge; Yang, Mu

    2015-03-01

    Double-shelled sea urchin-like yolk-shell Fe3O4/TiO2/Au microspheres were successfully synthesized through loading Au nanoparticles on the Fe3O4/TiO2 support by a in situ reduction of HAuCl4 with NaBH4 aqueous solution. These microspheres possess tunable cavity size, adjustable shell layers, high structural stability and large specific surface area. The Au nanoparticles of approximately 5 nm in diameter were loaded both on the TiO2 nanofibers and inside the cavities of sea urchin-like yolk-shell Fe3O4/TiO2 microspheres. The sea urchin-like structure composed of TiO2 nanofibers ensure the good distribution of the Au nanoparticles, while the novel double-shelled yolk-shell structure guarantees the high stability of the Au nanoparticles. Furthermore, the Fe3O4 magnetic core facilitates the convenient recovery of the catalyst by applying an external magnetic field. The Fe3O4/TiO2/Au microspheres display excellent activities and recycling properties in the catalytic reduction of 4-nitrophenol (4-NP): the rate constant is 1.84 min-1 and turnover frequency is 5457 h-1.

  1. In vitro fibroblast migration by sustained release of PDGF-BB loaded in chitosan nanoparticles incorporated in electrospun nanofibers for wound dressing applications.

    Science.gov (United States)

    Piran, Mehrdad; Vakilian, Saeid; Piran, Mehran; Mohammadi-Sangcheshmeh, Abdollah; Hosseinzadeh, Simzar; Ardeshirylajimi, Abdolreza

    2018-01-23

    Migration of fibroblasts into wound area is a critical phenomenon in wound healing process. We used an appropriate system to fabricate an electrospun bioactive scaffold with controlled release of PDGF-BB in order to induce migration of primary skin fibroblast cells. First of all, protein-loaded chitosan nanoparticles based on ionic gelation interaction between chitosan and sodium tripolyphosphate were prepared. Then polycaprolactone electrospun fibers containing chitosan nanoparticles or PDGF-BB-loaded chitosan nanoparticles were prepared. Cellular attachment and morphology of cells seeded on scaffolds with or without PDGF-BB were evaluated by using a fluorescence microscope and scanning electron microscopy. Cells were well-oriented 72 h after seeding on the scaffolds containing PDGF-BB. The mean aspect ratio of populations on scaffold containing PDGF-BB-loaded chitosan nanoparticles was significantly greater than those on the scaffold containing chitosan nanoparticles but no PDGF-BB. Furthermore, the Arp2 gene, which is involved in cell protrusion formation, showed about three times more expression at mRNA level, in cells seeding on PDGF-BB-containing scaffold compared to cells seeding on scaffold containing only chitosan nanoparticles, using Real Time PCR test. Finally, under agarose migration assay results demonstrated that cells' chemotaxic behavior was more toward scaffold containing PDGF-BB compared to the PDGF-BB alone or FBS group. In addition, in terms of distance, the cell mass could grow faster, in response to scaffold containing PDGF-BB compared to FBS or PDGF-BB alone; however, the number of migrating cells might be the same or significantly higher in the latter groups.

  2. NiO Nanofibers as a Candidate for a Nanophotocathode

    Directory of Open Access Journals (Sweden)

    Thomas J. Macdonald

    2014-04-01

    Full Text Available p-type NiO nanofibers have been synthesized from a simple electrospinning and sintering procedure. For the first time, p-type nanofibers have been electrospun onto a conductive fluorine doped tin oxide (FTO surface. The properties of the NiO nanofibers have been directly compared to that of bulk NiO nanopowder. We have observed a p-type photocurrent for a NiO photocathode fabricated on an FTO substrate.

  3. Hydrothermal synthesis of nanostructured TiO2 particles and characterization of their photocatalytic antimicrobial activity.

    Science.gov (United States)

    Erdural, Beril K; Yurum, Alp; Bakir, Ufuk; Karakas, Gurkan

    2008-02-01

    Nanostructured titania particles were synthesized by using hydrothermal processing and the photocatalytic antimicrobial activities were characterized. Both sol-gel synthesized and commercial TiO2 (anatase) samples were processed with two step hydrothermal treatments, under alkaline and neutral conditions. Scanning Electron Microscope (SEM) images showed that alkaline treatment yields nanofibers and lamellar structured particles from the commercial anatase and sol-gel synthesized samples respectively. Further treatment of nanofibers and nanostructured lamellar particles with distilled water results with crystal growth and the formation of nano structured bipyramidal crystalline particles. The photocatalytic antimicrobial activities of the samples were determined against Escherichia coil under irradiation. It was observed that the samples treated under alkaline conditions have improved activity than the original anatase samples. Limited activity and resulting time lag in bacterial inactivation were observed for hydrothermally treated samples with distilled water. However, a post treatment comprising the UV irradiation in aqueous conditions enhanced the photocatalytic activity.

  4. Electrospun Fibers of Cyclodextrins and Poly(cyclodextrins)

    OpenAIRE

    Alejandro Costoya; Angel Concheiro; Carmen Alvarez-Lorenzo

    2017-01-01

    Cyclodextrins (CDs) can endow electrospun fibers with outstanding performance characteristics that rely on their ability to form inclusion complexes. The inclusion complexes can be blended with electrospinnable polymers or used themselves as main components of electrospun nanofibers. In general, the presence of CDs promotes drug release in aqueous media, but they may also play other roles such as protection of the drug against adverse agents during and after electrospinning, and retention of ...

  5. Highly flexible transparent self-healing composite based on electrospun core-shell nanofibers produced by coaxial electrospinning for anti-corrosion and electrical insulation

    Science.gov (United States)

    An, Seongpil; Liou, Minho; Song, Kyo Yong; Jo, Hong Seok; Lee, Min Wook; Al-Deyab, Salem S.; Yarin, Alexander L.; Yoon, Sam S.

    2015-10-01

    Coaxial electrospinning was used to fabricate two types of core-shell fibers: the first type with liquid resin monomer in the core and polyacrylonitrile in the shell, and the second type with liquid curing agent in the core and polyacrylonitrile in the shell. These two types of core-shell fibers were mutually entangled and embedded into two flexible transparent matrices thus forming transparent flexible self-healing composite materials. Such materials could be formed before only using emulsion electrospinning, rather than coaxial electrospinning. The self-healing properties of such materials are associated with release of healing agents (resin monomer and cure) from nanofiber cores in damaged locations with the subsequent polymerization reaction filing the micro-crack with polydimethylsiloxane. Transparency of these materials is measured and the anti-corrosive protection provided by them is demonstrated in electrochemical experiments.

  6. TiO2 synthesis inspired by biomineralization: control of morphology, crystal phase, and light-use efficiency in a single process.

    Science.gov (United States)

    Nonoyama, Takayuki; Kinoshita, Takatoshi; Higuchi, Masahiro; Nagata, Kenji; Tanaka, Masayoshi; Sato, Kimiyasu; Kato, Katsuya

    2012-05-30

    Hydroxyapatite is mineralized along the long axis of collagen fiber during osteogenesis. Mimicking such biomineralization has great potential to control inorganic structures and is fast becoming an important next-generation inorganic synthesis method. Inorganic matter synthesized by biomineralization can have beautiful and functional structures that cannot be created artificially. In this study, we applied biomineralization to the synthesis of the only photocatalyst in practical use today, titanium dioxide (TiO(2)). The photocatalytic activity of TiO(2) mainly relates to three properties: morphology, crystal phase, and light-use efficiency. To optimize TiO(2) morphology, we used a simple sequential peptide as an organic template. TiO(2) mineralized by a β-sheet peptide nanofiber template forms fiber-like shapes that are not observed for mineralization by peptides in the shape of random coils. To optimize TiO(2) crystal phase, we mineralized TiO(2) with the template at 400 °C to transform it into the rutile phase and at 700 °C to transform it into a mixed phase of anatase and rutile. To optimize light-use efficiency, we introduced nitrogen atoms of the peptide into the TiO(2) structure as doped elemental material during sintering. Thus, this biomineralization method enables control of inorganic morphology, crystal phase, and light-use efficiency in a single process.

  7. Hierarchically Structured Electrospun Fibers

    Directory of Open Access Journals (Sweden)

    Nicole E. Zander

    2013-01-01

    Full Text Available Traditional electrospun nanofibers have a myriad of applications ranging from scaffolds for tissue engineering to components of biosensors and energy harvesting devices. The generally smooth one-dimensional structure of the fibers has stood as a limitation to several interesting novel applications. Control of fiber diameter, porosity and collector geometry will be briefly discussed, as will more traditional methods for controlling fiber morphology and fiber mat architecture. The remainder of the review will focus on new techniques to prepare hierarchically structured fibers. Fibers with hierarchical primary structures—including helical, buckled, and beads-on-a-string fibers, as well as fibers with secondary structures, such as nanopores, nanopillars, nanorods, and internally structured fibers and their applications—will be discussed. These new materials with helical/buckled morphology are expected to possess unique optical and mechanical properties with possible applications for negative refractive index materials, highly stretchable/high-tensile-strength materials, and components in microelectromechanical devices. Core-shell type fibers enable a much wider variety of materials to be electrospun and are expected to be widely applied in the sensing, drug delivery/controlled release fields, and in the encapsulation of live cells for biological applications. Materials with a hierarchical secondary structure are expected to provide new superhydrophobic and self-cleaning materials.

  8. TiO2 Nanoparticles Are Phototoxic to Marine Phytoplankton

    OpenAIRE

    Robert J Miller; Samuel Bennett; Keller, Arturo A.; Scott Pease; Lenihan, Hunter S.

    2012-01-01

    Nanoparticulate titanium dioxide (TiO(2)) is highly photoactive, and its function as a photocatalyst drives much of the application demand for TiO(2). Because TiO(2) generates reactive oxygen species (ROS) when exposed to ultraviolet radiation (UVR), nanoparticulate TiO(2) has been used in antibacterial coatings and wastewater disinfection, and has been investigated as an anti-cancer agent. Oxidative stress mediated by photoactive TiO(2) is the likely mechanism of its toxicity, and experiment...

  9. Electrospun porous carbon nanofiber@MoS2 core/sheath fiber membranes as highly flexible and binder-free anodes for lithium-ion batteries

    Science.gov (United States)

    Miao, Yue-E.; Huang, Yunpeng; Zhang, Longsheng; Fan, Wei; Lai, Feili; Liu, Tianxi

    2015-06-01

    Self-standing membranes of porous carbon nanofiber (PCNF)@MoS2 core/sheath fibers have been facilely obtained through a combination of electrospinning, high-temperature carbonization and the solvothermal reaction. PCNF fibers with porous channels are used as building blocks for the construction of hierarchical PCNF@MoS2 composites where thin MoS2 nanosheets are uniformly distributed on the PCNF surface. Thus, a three-dimensional open structure is formed, which provides a highly conductive pathway for rapid charge-transfer reactions, as well as greatly improving the surface active sites of MoS2 for fast lithiation/delithiation of Li+ ions. The highly flexible PCNF@MoS2 composite membrane electrode exhibits synergistically improved electrochemical performance with a high specific capacity of 954 mA h g-1 upon the initial discharge, a high rate capability of 475 mA h g-1 even at a high current density of 1 A g-1, and good cycling stability with almost 100% retention after 50 cycles, indicating its potential application as a binder-free anode for high-performance lithium-ion batteries.Self-standing membranes of porous carbon nanofiber (PCNF)@MoS2 core/sheath fibers have been facilely obtained through a combination of electrospinning, high-temperature carbonization and the solvothermal reaction. PCNF fibers with porous channels are used as building blocks for the construction of hierarchical PCNF@MoS2 composites where thin MoS2 nanosheets are uniformly distributed on the PCNF surface. Thus, a three-dimensional open structure is formed, which provides a highly conductive pathway for rapid charge-transfer reactions, as well as greatly improving the surface active sites of MoS2 for fast lithiation/delithiation of Li+ ions. The highly flexible PCNF@MoS2 composite membrane electrode exhibits synergistically improved electrochemical performance with a high specific capacity of 954 mA h g-1 upon the initial discharge, a high rate capability of 475 mA h g-1 even at a high

  10. Cell proliferation on PVA/sodium alginate and PVA/poly(γ-glutamic acid) electrospun fiber.

    Science.gov (United States)

    Yang, Jen Ming; Yang, Jhe Hao; Tsou, Shu Chun; Ding, Chian Hua; Hsu, Chih Chin; Yang, Kai Chiang; Yang, Chun Chen; Chen, Ko Shao; Chen, Szi Wen; Wang, Jong Shyan

    2016-09-01

    To overcome the obstacles of easy dissolution of PVA nanofibers without crosslinking treatment and the poor electrospinnability of the PVA cross-linked nanofibers via electrospinning process, the PVA based electrospun hydrogel nanofibers are prepared with post-crosslinking method. To expect the electrospun hydrogel fibers might be a promising scaffold for cell culture and tissue engineering applications, the evaluation of cell proliferation on the post-crosslinking electrospun fibers is conducted in this study. At beginning, poly(vinyl alcohol) (PVA), PVA/sodium alginate (PVASA) and PVA/poly(γ-glutamic acid) (PVAPGA) electrospun fibers were prepared by electrospinning method. The electrospun PVA, PVASA and PVAPGA nanofibers were treated with post-cross-linking method with glutaraldehyde (Glu) as crosslinking agent. These electrospun fibers were characterized with thermogravimetry analysis (TGA) and their morphologies were observed with a scanning electron microscope (SEM). To support the evaluation and explanation of cell growth on the fiber, the study of 3T3 mouse fibroblast cell growth on the surface of pure PVA, SA, and PGA thin films is conducted. The proliferation of 3T3 on the electrospun fiber surface of PVA, PVASA, and PVAPGA was evaluated by seeding 3T3 fibroblast cells on these crosslinked electrospun fibers. The cell viability on electrospun fibers was conducted with water-soluble tetrazolium salt-1 assay (Cell Proliferation Reagent WST-1). The morphology of the cells on the fibers was also observed with SEM. The results of WST-1 assay revealed that 3T3 cells cultured on different electrospun fibers had similar viability, and the cell viability increased with time for all electrospun fibers. From the morphology of the cells on electrospun fibers, it is found that 3T3 cells attached on all electrospun fiber after 1day seeded. Cell-cell communication was noticed on day 3 for all electrospun fibers. Extracellular matrix (ECM) productions were found and

  11. Fabricating microparticles/nanofibers composite and nanofiber scaffold with controllable pore size by rotating multichannel electrospinning.

    Science.gov (United States)

    Huang, Yi-You; Wang, De-Yao; Chang, Lee-Lee; Yang, Ying-Chi

    2010-01-01

    Polymeric nanofibers fabricated via electrospinning are regarded as promising scaffolds for biomimicking a native extracellular matrix. However, electrospun scaffolds have poor porosity, resulting in cells being unable to infiltrate into the scaffolds but grow only on its surface. In this study, we modified regular electrospinning into rotating multichannel electrospinning (RM-ELSP) to produce microparticles and nanofibers simultaneously. Gelatin nanofibers (0.1-1 microm) and polycaprolactone (PCL) microparticles (0.5-10 microm) were formed and well-mixed. Adjusting the concentration of PCL and/or gelatin, we can fabricate various microparticles/nanofibers composites with different sizes of PCL particles and different diameters of gelatin nanofibers depending on their concentrations (2-10%) during electrospinning. Using PCL particles as a pore generator, we obtained gelatin nanofiber scaffolds with controllable pore size and porosity. Cells adhere and grow into the scaffold easily during in vitro cell culture.

  12. Efficient photodegradation of methyl violet dye using TiO2/Pt and TiO2/Pd photocatalysts

    Science.gov (United States)

    Saeed, Khalid; Khan, Idrees; Gul, Tamanna; Sadiq, Mohammad

    2017-11-01

    Titanium oxide supported palladium (TiO2/Pd) and titanium oxide supported platinum (TiO2/Pt) nanoparticles were prepared from their precursors through the incipient wetness method. The TiO2/Pd and TiO2/Pt nanoparticles were characterized by scanning electron microscopy (SEM), and energy dispersive X-rays (EDX), while the photodegradation study of methyl violet was performed by UV/VIS spectrophotometry. The morphological study shows that the Pd and Pt were well deposited on the surface of TiO2, which was confirmed by EDX. Both TiO2/Pd and TiO2/Pt nanoparticles were used as photocatalysts for the photodegradation of methyl violet in aqueous media under UV-light irradiation. The photodegradation study revealed that the TiO2/Pd and TiO2/Pt nanoparticles degraded about 95 and 78% of dye within 20 min, respectively. The effect of various parameters such as catalyst dosage, concentration of dye, and medium on the photocatalytic degradation was examined. The activity of recovered TiO2/Pd and TiO2/Pt nanoparticles was studied.

  13. Novel atmospheric plasma enhanced chitosan nanofiber/gauze composite wound dressings

    Science.gov (United States)

    Electrospun chitosan nanofibers were deposited onto atmospheric plasma treated cotton gauze to create a novel composite bandage with higher adhesion, better handling properties, enhanced bioactivity, and moisture management. Plasma treatment of the gauze substrate was performed to improve the durabi...

  14. Water Adsorption on TiO2

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Wendt, Stefan; Besenbacher, Flemming

    2010-01-01

    Scanning Tunneling Microscopy (STM) studies and Density Functional Theory (DFT) investigations of the interaction of water with the rutile TiO2 (110) surface are summarized. From high-resolution STM the following reactions have been revealed: water adsorption and diffusion in the Ti troughs, water...... dissociation in bridging oxygen vacancies, assembly of adsorbed water monomers into rapidly diffusing water dimers, and formation of water dimers by reduction of oxygen molecules. The STM results are rationalized based on DFT calculations, revealing the bonding geometries and reaction pathways of the water...

  15. Electrospun biocompatible Chitosan/MIL-101 (Fe) composite nanofibers for solid-phase extraction of Δ9-tetrahydrocannabinol in whole blood samples using Box-Behnken experimental design.

    Science.gov (United States)

    Asiabi, Mina; Mehdinia, Ali; Jabbari, Ali

    2017-01-06

    The nanofibers of biocompatible Chitosan/MIL-101 (Fe) composite were synthesized by a simple, cheap and accessible electrospining method and applied for mat-based extraction of trace amount of Δ9-tetrahydrocannabinol (THC) from human whole blood sample following its combination by high performance liquid chromatography-ultraviolet detection. The composite nanofibres were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and N2 adsorption-desorption experiments. The volume of eluting solvent, sorbent amount, pH and% NaCl (w/v) influencing on the responses were investigated using factorial experimental design. The optimum point was achieved by analysis of the results according to design expert (DX) software. The volume of eluting solvent, sorbent amount and pH were significant variables, and 150μL, 7mg and 7.0 were respectively chosen for obtaining the best extraction response. Under the optimum conditions, the method was exhibited a linear range of 0.1-100μgL-1 (R2=0.9943) for THC with a detection limit of 0.04μgL-1. Acceptable values for intra-day (3.2%) and inter-day (4.8%) relative standard deviations were obtained. The high preconcentration factor (970) and satisfactory recoveries (88.2%-92.4%) in whole blood samples were achieved which proved the capability of the method for trace determination of THC in the human whole blood samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Electrospun Based Polyaniline Sensors - A Review

    Science.gov (United States)

    Rozemarie, M. L.; Andrei, B.; Liliana, H.; Cramariuc, R.; Cramariuc, O.

    2017-06-01

    Polyaniline is a polymer with outstanding electronic conductivity and good response to molecules at room temperature. This review focuses on the many uses of electrospun polyaniline nanofibers as chemical sensor with high sensitivity and functionality, providing a concise report of the present status of polyaniline gas sensing applications. Latest developments in this area are reported and the capability of PANI sensors to detect various gases is emphasized. Difficulties that may obstruct practical uses of these sensors are also summarized.

  17. The support of bone marrow stromal cell differentiation by airbrushed nanofiber scaffolds.

    Science.gov (United States)

    Tutak, Wojtek; Sarkar, Sumona; Lin-Gibson, Sheng; Farooque, Tanya M; Jyotsnendu, Giri; Wang, Dongbo; Kohn, Joachim; Bolikal, Durgadas; Simon, Carl G

    2013-03-01

    Nanofiber scaffolds are effective for tissue engineering since they emulate the fibrous nanostructure of native extracellular matrix (ECM). Although electrospinning has been the most common approach for fabricating nanofiber scaffolds, airbrushing approaches have also been advanced for making nanofibers. For airbrushing, compressed gas is used to blow polymer solution through a small nozzle which shears the polymer solution into fibers. Our goals were 1) to assess the versatility of airbrushing, 2) to compare the properties of airbrushed and electrospun nanofiber scaffolds and 3) to test the ability of airbrushed nanofibers to support stem cell differentiation. The results demonstrated that airbrushing could produce nanofibers from a wide range of polymers and onto a wide range of targets. Airbrushing was safer, 10-fold faster, 100-fold less expensive to set-up and able to deposit nanofibers onto a broader range of targets than electrospinning. Airbrushing yielded nanofibers that formed loosely packed bundles of aligned nanofibers, while electrospinning produced un-aligned, single nanofibers that were tightly packed and highly entangled. Airbrushed nanofiber mats had larger pores, higher porosity and lower modulus than electrospun mats, results that were likely caused by the differences in morphology (nanofiber packing and entanglement). Airbrushed nanofiber scaffolds fabricated from 4 different polymers were each able to support osteogenic differentiation of primary human bone marrow stromal cells (hBMSCs). Finally, the differences in airbrushed versus electrospun nanofiber morphology caused differences in hBMSC shape where cells had a smaller spread area and a smaller volume on airbrushed nanofiber scaffolds. These results highlight the advantages and disadvantages of airbrushing versus electrospinning nanofiber scaffolds and demonstrate that airbrushed nanofiber scaffolds can support stem cell differentiation. Published by Elsevier Ltd.

  18. Characterization and Biocompatibility of Biopolyester Nanofibers

    Science.gov (United States)

    Ishii, Daisuke; Ying, Tang Hui; Yamaoka, Tetsuji; Iwata, Tadahisa

    2009-01-01

    Biodegradable nanofibers are expected to be promising scaffold materials for biomedical engineering, however, biomedical applications require control of the degradation behavior and tissue response of nanofiber scaffolds in vivo. For this purpose, electrospun nanofibers of poly(hydroxyalkanoate)s (PHAs) and poly(lactide)s (PLAs) were subjected to degradation tests in vitro and in vivo. In this review, characterization and biocompatibility of nanofibers derived from PHAs and PLAs are described. In particular, the effects of the crystalline structure of poly[(R)-3-hydroxybutyrate], stereocomplex structure of PLA, and monomer composition of PHA on the degradation behaviors are described in detail. These studies show the potential of biodegradable polyester nanofibers as scaffold material, for which suitable degradation rate and regulated interaction with surrounding tissues are required.

  19. Characterization and Biocompatibility of Biopolyester Nanofibers

    Directory of Open Access Journals (Sweden)

    Tang Hui Ying

    2009-10-01

    Full Text Available Biodegradable nanofibers are expected to be promising scaffold materials for biomedical engineering, however, biomedical applications require control of the degradation behavior and tissue response of nanofiber scaffolds in vivo. For this purpose, electrospun nanofibers of poly(hydroxyalkanoates (PHAs and poly(lactides (PLAs were subjected to degradation tests in vitro and in vivo. In this review, characterization and biocompatibility of nanofibers derived from PHAs and PLAs are described. In particular, the effects of the crystalline structure of poly[(R-3-hydroxybutyrate], stereocomplex structure of PLA, and monomer composition of PHA on the degradation behaviors are described in detail. These studies show the potential of biodegradable polyester nanofibers as scaffold material, for which suitable degradation rate and regulated interaction with surrounding tissues are required.

  20. Adsorption of silver ions on polypyrrole embedded electrospun nanofibrous polyethersulfone membranes.

    Science.gov (United States)

    Wu, Jiunn-Jong; Lee, Hsiu-Wen; You, Jiann-Hwa; Kau, Yi-Chuan; Liu, Shih-Jung

    2014-04-15

    In this study we developed polypyrrole embedded electrospun nanofibrous polyethersulfone nanofibrous membranes for the removal of silver ions. Polypyrrole and polyethersulfone dissolved in N-methyl-2-pyrrolidone (NMP) were electrospun into nanofibrous membranes via an electrospinning process. The morphology of as-spun polypyrrole/polyethersulfone nanofibers was examined by scanning electron microscopy. The average diameter of electrospun nanofibers ranged from 410 nm to 540 nm. The adsorption capability of nanofibrous polypyrrole/polyethersulfone membranes was measured and compared with that of bulk polypyrrole. The influence of various process conditions on adsorption efficiency was also examined. The experimental results suggested that the electrospun nanofibrous membranes exhibited good silver ion uptake capabilities. The metal uptake of nanofibrous membranes increased with the initial metal ion concentrations and the pH value, while decreased with the temperature and the filtering rate of the solutions. Furthermore, the electrospun membrane could be reused after the recovery process. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Preparation and characterization of electrospun poly(phthalazinone ether nitrile ketone) membrane with novel thermally stable properties

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Gang; Zhang, Hao; Qian, Bingqing [Carbon Research Laboratory, Liaoning Key Lab for Energy Materials and Chemical Engineering, State Key Lab of Fine Chemicals, Dalian University of Technology, Dalian 116024 (China); Wang, Jinyan, E-mail: wangjinyan@dlut.edu.cn [Department of Polymer Science and Materials, Dalian University of Technology, Dalian 116024 (China); Jian, Xigao [Department of Polymer Science and Materials, Dalian University of Technology, Dalian 116024 (China); Qiu, Jieshan, E-mail: jqiu@dlut.edu.cn [Carbon Research Laboratory, Liaoning Key Lab for Energy Materials and Chemical Engineering, State Key Lab of Fine Chemicals, Dalian University of Technology, Dalian 116024 (China)

    2015-10-01

    Highlights: • Poly (phthalazinone ether nitrile ketone) (PPENK) was used to successfully prepare nanofiber membranes by electrospinning. • Electrospun membrane exhibits a good thermostability. • Electrospun membrane. - Abstract: Electrospun nanofibrous membranes have several applications because of their excellent properties, such as high porosity, small fiber diameter, and large surface area. However, high-temperature resistant electrospun membranes remain a challenge because of the absence of precursors that offer spinnability, scalability, and superior thermal stability. In this study, poly(phthalazinone ether nitrile ketone) (PPENK) was used to successfully prepare nanofiber membranes by electrospinning. Electrospun PPENK membranes were characterized by scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, and tensile stress–strain tests. Results indicated that the prepared electrospun membranes had a very high glass transition temperature, superior chemical resistance, and excellent mechanical strength. These desirable properties broaden their potential application in membranes and treatment of various hot fluid streams without strict temperature control.

  2. Rational design of nanofiber scaffolds for orthopedic tissue repair and regeneration

    Science.gov (United States)

    Ma, Bing; Xie, Jingwei; Jiang, Jiang; Shuler, Franklin D; Bartlett, David E

    2013-01-01

    This article reviews recent significant advances in the design of nanofiber scaffolds for orthopedic tissue repair and regeneration. It begins with a brief introduction on the limitations of current approaches for orthopedic tissue repair and regeneration. It then illustrates that rationally designed scaffolds made up of electrospun nanofibers could be a promising solution to overcome the problems that current approaches encounter. The article also discusses the intriguing properties of electrospun nanofibers, including control of composition, structures, orders, alignments and mechanical properties, use as carriers for topical drug and/or gene sustained delivery, and serving as substrates for the regulation of cell behaviors, which could benefit musculoskeletal tissue repair and regeneration. It further highlights a few of the many recent applications of electrospun nanofiber scaffolds in repairing and regenerating various orthopedic tissues. Finally, the article concludes with perspectives on the challenges and future directions for better design, fabrication and utilization of nanofiber scaffolds for orthopedic tissue engineering. PMID:23987110

  3. Porous TiO{sub 2} nanofibers decorated CdS nanoparticles by SILAR method for enhanced visible-light-driven photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Fengyu; Hou, Dongfang, E-mail: dfhouok@126.com; Hu, Fuchao; Xie, Kui; Qiao, Xiuqing; Li, Dongsheng, E-mail: lidongsheng1@126.com

    2017-01-01

    Graphical abstract: A heterojunction photocatalyst with CdS Nanoparticles self-assembled via SILAR Method at surfaces of electrospun TiO2 nanofibers shows enhanced visible-light photocatalytic activities. - Highlights: • Combined electrospinning and successive ionic layer adsorption and reaction process. • Pouous TiO{sub 2} nanofibers decorated CdS nanoparticles. • Synergetic effect of photosensitization and heterojunction. - Abstract: 1D porous CdS nanoparticles/TiO{sub 2} nanofibers heterostructure has been fabricated via simple electrospinning and a successive ionic layer adsorption and reaction (SILAR) process. The morphology, composition, and optical properties of the resulting CdS/TiO{sub 2} heterostructures can be rationally tailored through changing the SILAR cycles. The photocatalytic hydrogen evolution and decomposition of rhodamine B (RhB) of the as-synthesized heterostructured photocatalysts were investigated under visible light irradiation. Compared to TiO{sub 2} nanofibers,the as-obtained CdS/TiO{sub 2} heterostructures exhibit enhanced photocatalytic activity for hydrogen production and decomposition of RhB under visible-light irradiation. The heterojunction system performs best with H{sub 2} generation rates of 678.61 μmol h{sup −1} g{sup −1} under visible light irradiation which benefits from the two effects: (a) the 1D porous nanofibrous morphology contributes to not only more active sites but also more efficient transfer of the photogenerated charges (b) the synergetic effect of heterojunction and photosensitization reducing the recombination of photogenerated electrons and holes.

  4. Silicon protected with atomic layer deposited TiO2

    DEFF Research Database (Denmark)

    Seger, Brian; Tilley, S. David; Pedersen, Thomas

    2013-01-01

    /electrolyte interface if the potential is significantly more anodic than the TiO2 conduction band due to moderate to large band bending. This means that the lesser doped TiO2 can be used to prevent the inadvertent oxidation of sensitive species on the surface (e.g. H2 evolution catalysts) as long as the redox...... potential of the material is significantly more anodic than the TiO2 conduction band. Conversely, for situations where an oxidative process on the surface is desired, highly doped TiO2 may be used to enable current flow via tunneling....

  5. Corrosion Behavior of Brass In Tio2 Nanofluids

    Science.gov (United States)

    Wu, Kai; Ge, Hong-Hua; Wang, Feng; Zhou, Hong-Wang

    2017-09-01

    Corrosion behavior of brass electrode in TiO2 nanofluids was analyzed using electrochemical impedance spectroscopy. The experimental results show that TiO2 nanoparticles promote corrosion of brass. The corrosion resistance of brass electrode decreases with the increase of the temperature of the TiO2 nanofluids. Sodium dodecyl benzene sulfonate (SDBS) is a dispersant in nanofluids and also appears corrosion inhibition to brass, and the corrosion inhibition enhances with the increase of SDBS concentration. The corrosion resistance of brass in TiO2 nanofluids would decrease when the concentration of dispersant SDBS exceeds a certain value.

  6. Fabrication of a TiO2-P25/(TiO2-P25+TiO2 nanotubes junction for dye sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Nguyen Huy Hao

    2016-08-01

    Full Text Available The dye sensitized solar cell (DSSC, which converts solar light into electric energy, is expected to be a promising renewable energy source for today's world. In this work, dye sensitized solar cells, one containing a single layer and one containing a double layer, were fabricated. In the double layer DSSC structure, the under-layer was TiO2-P25 film, and the top layer consisted of a mixture of TiO2-P25 and TiO2 nanotubes. The results indicated that the efficiency of the DSSC with the double layer structure was a significant improvement in comparison to the DSSC consisting of only a single film layer. The addition of TiO2-P25 in the top layer caused an improvement in the adsorption of dye molecules on the film rather than on the TiO2 nanotubes only. The presence of the TiO2 nanotubes together with TiO2-P25 in the top layer revealed the enhancement in harvesting the incident light and an improvement of electron transport through the film.

  7. Increasing Mechanical Properties of 2-D-Structured Electrospun Nylon 6 Non-Woven Fiber Mats.

    Science.gov (United States)

    Xiang, Chunhui; Frey, Margaret W

    2016-04-07

    Tensile strength, Young's modulus, and toughness of electrospun nylon 6 non-woven fiber mats were improved by increasing individual nanofiber strength and fiber-fiber load sharing. Single-walled carbon nanotubes (CNTs) were used as reinforcement to increase the strength of the electrospun nylon 6 nanofibers. Young's modulus, tensile strength, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % solutions increased 51%, 87%, and 136%, respectively, after incorporating 1 wt % CNTs into the nylon 6 nanofibers. Three methods were investigated to enhance fiber-fiber load sharing: increasing friction between fibers, thermal bonding, and solvent bonding. The addition of beaded nylon 6 nanofibers into the non-woven fiber mats to increase fiber-fiber friction resulted in a statistically significantly increase in Young's modulus over comparable smooth non-woven fiber mats. After annealing, tensile strength, elongation, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % + 10 wt % solutions increased 26%, 28%, and 68% compared to those from 20 wt % solutions. Solvent bonding with formic acid vapor at room temperature for 30 min caused increases of 56%, 67%, and 39% in the Young's modulus, tensile strength, and toughness of non-woven fiber mats, respectively. The increases attributed to increased individual nanofiber strength and solvent bonding synergistically resulted in the improvement of Young's modulus of the electrospun nylon 6 non-woven fiber mats.

  8. Increasing Mechanical Properties of 2-D-Structured Electrospun Nylon 6 Non-Woven Fiber Mats

    Directory of Open Access Journals (Sweden)

    Chunhui Xiang

    2016-04-01

    Full Text Available Tensile strength, Young’s modulus, and toughness of electrospun nylon 6 non-woven fiber mats were improved by increasing individual nanofiber strength and fiber–fiber load sharing. Single-walled carbon nanotubes (CNTs were used as reinforcement to increase the strength of the electrospun nylon 6 nanofibers. Young’s modulus, tensile strength, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % solutions increased 51%, 87%, and 136%, respectively, after incorporating 1 wt % CNTs into the nylon 6 nanofibers. Three methods were investigated to enhance fiber–fiber load sharing: increasing friction between fibers, thermal bonding, and solvent bonding. The addition of beaded nylon 6 nanofibers into the non-woven fiber mats to increase fiber-fiber friction resulted in a statistically significantly increase in Young’s modulus over comparable smooth non-woven fiber mats. After annealing, tensile strength, elongation, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % + 10 wt % solutions increased 26%, 28%, and 68% compared to those from 20 wt % solutions. Solvent bonding with formic acid vapor at room temperature for 30 min caused increases of 56%, 67%, and 39% in the Young’s modulus, tensile strength, and toughness of non-woven fiber mats, respectively. The increases attributed to increased individual nanofiber strength and solvent bonding synergistically resulted in the improvement of Young’s modulus of the electrospun nylon 6 non-woven fiber mats.

  9. Multi-functional and durable nanofiber-fabric layered composite for protective application

    Science.gov (United States)

    A multifunctional and durable nanofiber-fabric-layered composite (NFLC) material was prepared by depositing electrospun Ag/PAN hybrid nanofibers onto a Nylon/cotton 50: 50 fabric substrate. The NFLCs showed excellent aerosol barrier efficiency and good air/moisture permeability. In addition, they sh...

  10. Performance of electrodes synthesized with polyacrylonitrile-based carbon nanofibers for application in electrochemical sensors and biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Adabi, Mahdi [Department of Medical Nanotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Saber, Reza [Department of Medical Nanotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Faridi-Majidi, Reza, E-mail: refaridi@sina.tums.ac.ir [Department of Medical Nanotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Center of Excellence in Electrochemistry, Faculty of Chemistry, University of Tehran, Tehran (Iran, Islamic Republic of); Faridbod, Farnoush [Science and Technology in Medicine (RCSTIM), Tehran University of Medical Sciences, Tehran, Iran. (Iran, Islamic Republic of)

    2015-03-01

    The purpose of this work was to investigate the performance of electrodes synthesized with Polyacrylonitrile-based carbon nanofibers (PAN-based CNFs). The homogenous PAN solutions with different concentrations were prepared and electrospun to acquire PAN nanofibers and then CNFs were fabricated by heat treatment. The effective parameters for the production of electrospun CNF electrode were investigated. Scanning electron microscopy (SEM) was used to characterize electrospun nanofibers. Cyclic voltammetry was applied to investigate the changes of behavior of electrospun CNF electrodes with different diameters. The structure of CNFs was also evaluated via X-ray diffraction (XRD) and Raman spectroscopy. The results exhibited that diameter of nanofibers reduced with decreasing polymer concentration and applied voltage and increasing tip-to-collector distance, while feeding rate did not have significant effect on nanofiber diameter. The investigations of electrochemical behavior also demonstrated that cyclic voltammetric response improved as diameter of CNFs electrode decreased. - Highlights: • Electrospun CNFs can be directly used as working electrode. • Cyclic voltammetric response improved as diameter of CNFs electrode decreased. • The diameter of nanofibers reduced with decreasing polymer concentration. • The diameter of nanofibers reduced with decreasing applied voltage. • The diameter of nanofibers reduced with increasing tip-to-collector distance.

  11. Controlled Directional Growth of TiO2 Nanotubes

    DEFF Research Database (Denmark)

    In, Su-il; Hou, Yidong; Abrams, Billie

    2010-01-01

    We demonstrate how the anodization direction and growth rate of vertically aligned, highly ordered TiO2 nanotube (NT) arrays can be controlled and manipulated by the local concentration of O-2 in the electrolyte. This leads to the growth of highly active TiO2 NT arrays directly on nonconducting s...

  12. PEMILIHAN JENIS BULIR POLIMER SEBAGAI PENYANGGA MATERIAL FOTOKATALIS TIO2

    Directory of Open Access Journals (Sweden)

    Hasniah Aliah

    2014-05-01

    Full Text Available Salah satu cara untuk meningkatkan aktivitas fotokatalitik suatu material katalis adalah dengan melapiskan material katalis Titanium dioksida (TiO2  pada permukaan polimer yang berukuran cukup besar, ringan, transparan dan bersifat termoplastik.  Untuk memilih jenis polimer terbaik sebagai material penyangga katalis, dilakukan pengujian pelapisan partikel TiO2 pada tiga jenis polimer berbentuk bulir, yaitu polystyrene (PS, linear-low density polyethylene (LLDPE, dan polypropilene (PP.Pelapisan material TiO2 di permukaan polimer dilakukan dengan menggunakan teknik thermalmilling berbasis oven listrik. Temperatur dalam proses milling diatur di sekitar titik HDT (Heat Deflection Temperaturematerial polimer dan berlangsung selama 60 menit.  Massa jenis dan transmitansi polimer setelah dilapisi TiO2 merupakan parameter fisik yang menjadi acuan dalam pemilihan polimer penyangga katalis. Imobilisasi menggunakan teknik thermal milling menghasilkan polimer PP berlapis katalis TiO2 yang homogen. Pabrikasi dengan parameter milling 100°C dan 60 menit menghasilkan PP berlapis katalis TiO2 dengan massa jenis rata-rata 0,872 g/cm3 sehingga dapat mengapung di permukaan air.  Di samping itu, PP berlapis TiO2 mempunyai transmitansi 58%. Polimer PP inilah yang kemudian dipilih sebagai material penyangga katalis TiO2 dalam proses penelitian selanjutnya.

  13. Multifunctional electroactive electrospun nanofiber structures from water solution blends of PVA/ODA-MMT and poly(maleic acid-alt-acrylic acid): effects of Ag, organoclay, structural rearrangement and NaOH doping factors

    Science.gov (United States)

    Şimşek, Murat; Rzayev, Zakir M. O.; Bunyatova, Ulviya

    2016-06-01

    Novel multifunctional colloidal polymer nanofiber electrolytes were fabricated by green reactive electrospinning nanotechnology from various water solution/dispersed blends of poly (vinyl alcohol-co-vinyl acetate) (PVA)/octadecyl amine-montmorillonite (ODA-MMT) as matrix polymer nanocomposite and poly(maleic acid-alt-acrylic acid) (poly(MAc-alt-AA) and/or its Ag-carrying complex as partner copolymers. Polymer nanofiber electrolytes were characterized using FTIR, XRD, thermal (DSC, TGA-DTG), SEM, and electrical analysis methods. Effects of partner copolymers, organoclay, in situ generated silver nanoparticles (AgNPs), and annealing procedure on physical and chemical properties of polymer composite nanofibers were investigated. The electrical properties (resistance, conductivity, activation energy) of nanofibers with/without NaOH doping agent were also evaluated. This work presented a structural rearrangement of nanofiber mats by annealing via decarboxylation of anhydride units with the formation of new conjugated double bond sites onto partner copolymer main chains. It was also found that the semiconductor behaviors of nanofiber structures were essentially improved with increasing temperature and fraction of partner copolymers as well as presence of organoclay and AgNPs in nanofiber composite.

  14. Fabrication, optimization and characterization of electrospun poly(caprolactone)/gelatin/graphene nanofibrous mats.

    Science.gov (United States)

    Heidari, Mina; Bahrami, Hajir; Ranjbar-Mohammadi, Marziyeh

    2017-09-01

    Recently graphene-based materials have been exploited widely in graphene-polymer nanocomposites and hold notable potential for various applications. In this study novel graphene-incorporated poly(caprolactone)/gelatin nanofibrous web were produced by electrospinning technique using acetic acid as a cost-effective eco-friendly solvent. Response surface methodology was used for optimizing the diameter of the electrospun nanofibrous web. To tailor electrospun nanofibers with suitable mechanical and electrical properties, the impact of affecting electrospinning parameters was studied. Our results show that, with increasing the PCL/gelatin ratio, the diameter of nanofibers increases, whereas increasing graphene concentration decreased the diameter of nanofibers up to an optimum content. With the incorporation of 1.5% graphene into PCL/gelatin matrix the tensile strength and Young modulus of nanofibrous mat considerably increased by 117 and 128% respectively. The electrical conductivity results demonstrated that nanofibrous mats own nearly 11 times higher conductivity than that of PCL/gelatin nanofibers when the graphene concentration reached the percolation threshold. Contact angle measurements confirmed that graphene-incorporated electrospun nanofibers were more hydrophilic than that of neat nanofibrous mats. Cellular toxicity results of electrospun nanofibers ascertained almost no toxicity to PC12 cells. The morphology of electrospun nanofibers was investigated by means of scanning electron microscopy (SEM). FTIR and DSC analysis revealed that there might be possible interactions between graphene and PCL/gelatin matrix. XRD analysis demonstrated that graphene-incorporated PCL/gelatin nanofibers exhibited higher crystallinity. The uniform dispersion of graphene nanosheets in nanofibrous mat was also verified through Raman spectroscopy. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Dendritic α-Fe2O3/TiO2 nanocomposites with improved visible light photocatalytic activity.

    Science.gov (United States)

    Li, Xin; Lin, Huiming; Chen, Xiang; Niu, Hao; Liu, Jiuyu; Zhang, Ting; Qu, Fengyu

    2016-04-07

    The design and synthesis of unique novel heterostructures for high-performance photocatalytic activity has exerted a tremendous fascination and has recently attracted intensive attention. In this work, a branch-like α-Fe2O3/TiO2 heterostructure has been synthesized controllably through an electrospinning method combined with a hydrothermal approach. The backbone of the heterostructure is composed of a 3D porous TiO2 nanofiber (∼70 nm in diameter) network with plenty of α-Fe2O3 nanorods (100-200 nm in length) deposited on them. The novel branch-like nanocomposites have an abundantly porous structure as well as large surface areas (up to 42.8 m(2) g(-1)). In addition, their visible light photodegradation behaviour towards organic dyes, including Congo red (CR), methylene blue (MB), eosin red (ER) and methyl orange (MO), was investigated. Their excellent photocatalytic performances are attributed to their large surfaces, improved visible light absorption and high separation efficiency of the photogenerated electrons/holes. Furthermore, the degradation process was further studied by varying the amount of α-Fe2O3 deposited. The sample α-Fe2O3/TiO2-3 possessed the best performance to efficiently decolor CR solution even at a high concentration of 50 mg L(-1) (160 min, 94 mg g(-1)), ascribed to the high adsorption capacity derived from the large surface, strong electrostatic interaction and structural match between α-Fe2O3/TiO2-3 and CR. These α-Fe2O3/TiO2 heterostructures exhibit great potential for decontamination of organic pollutants in waste water under visible light.

  16. Nanofiber diameter as a critical parameter affecting skin cell response.

    Science.gov (United States)

    Pelipenko, Jan; Kocbek, Petra; Kristl, Julijana

    2015-01-23

    Electrospun polymer nanofibers have opened new opportunities in the rapidly evolving field of tissue engineering, particularly due to their topography and variability of available biomaterials. In order to better understand nanofiber influence on cell growth, the impact of their diameter was systematically examined. In this study homogenous, randomly oriented poly(vinyl alcohol) nanofibers with five different average diameters, ranging from 70nm to 1120nm, were produced, characterized and their impact on morphology, proliferation and mobility of keratinocytes and skin fibroblasts was evaluated. The results have shown that nanofiber diameter affects cell response and that this response is cell line specific. Nanofiber thickness affected size, morphology and actine organization of keratinocytes much more than fibroblasts. Specifically, the keratinocyte grown on nanofibers were more spherical and smaller compared to the control cells, while the fibroblasts were much less affect. They stayed almost unchanged and spread across growth surface. The cell proliferation determined based on their metabolic activity was the highest, when keratinocytes were grown on 305nm thick nanofibers, whereas proliferation of fibroblasts grown similar nanofibers was decreased. Finally, fibroblasts exerted higher mobility than keratinocytes. Both tested cell lines on nanofiber diameters of 300nm resulted in decreased cell mobility. These findings suggest that the control over nanofiber diameter offers promising possibility to better design the tissue scaffolds, since cells distinguish between differently sized nanofibers and respond accordingly. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. SYNTESIST AND CHARACTERISATION TiO2-Cu PHOTOCATALYST

    Directory of Open Access Journals (Sweden)

    Kapti Riyani

    2015-11-01

    Full Text Available This study begins with the manufacture of TiO2 -Cu photocatalyst by means of wet impregnation and fotodeposisi, the mole ratio of TiO2: Cu2+ is 100: 0; 99: 1; 98: 2; 97: 3 and 96: 4. Photocatalysts were characterized using SEM, UV-Vis DRS, FTIR and XRD. The results showed has been successfully carried out the synthesis of TiO2-Cu. From SEM characterization shows that the addition of Cu metal will alter the morphology of TiO2 photocatalysts. Based on analysis of UV-Vis DRS, the addition of Cu metal dopant to decrease the energy band gap of TiO2. From XRD analysis appears 2θ value at 29.607 and 48.401 which indicates the formation of monoclinic crystal H2Ti3O7. FTIR analysis results indicate a change in the specific uptake of TiO2 indicating a change in the structure of TiO2

  18. Oriented epitaxial TiO2 nanowires for water splitting

    Science.gov (United States)

    Hou, Wenting; Cortez, Pablo; Wuhrer, Richard; Macartney, Sam; Bozhilov, Krassimir N.; Liu, Rong; Sheppard, Leigh R.; Kisailus, David

    2017-06-01

    Highly oriented epitaxial rutile titanium dioxide (TiO2) nanowire arrays have been hydrothermally grown on polycrystalline TiO2 templates with their orientation dependent on the underlying TiO2 grain. Both the diameter and areal density of the nanowires were tuned by controlling the precursor concentration, and the template surface energy and roughness. Nanowire tip sharpness was influenced by precursor solubility and diffusivity. A new secondary ion mass spectrometer technique has been developed to install additional nucleation sites in single crystal TiO2 templates and the effect on nanowire growth was probed. Using the acquired TiO2 nanowire synthesis knowhow, an assortment of nanowire arrays were installed upon the surface of undoped TiO2 photo-electrodes and assessed for their photo-electrochemical water splitting performance. The key result obtained was that the presence of short and dispersed nanowire arrays significantly improved the photocurrent when the illumination intensity was increased from 100 to 200 mW cm-2. This is attributed to the alignment of the homoepitaxially grown nanowires to the [001] direction, which provides the fastest charge transport in TiO2 and an improved pathway for photo-holes to find water molecules and undertake oxidation. This result lays a foundation for achieving efficient water splitting under conditions of concentrated solar illumination.

  19. Anatase TiO2 sheet-assisted synthesis of Ti(3+) self-doped mixed phase TiO2 sheet with superior visible-light photocatalytic performance: Roles of anatase TiO2 sheet.

    Science.gov (United States)

    Zhang, Xiaojie; Zuo, Guoqing; Lu, Xin; Tang, Changqing; Cao, Shuo; Yu, Miao

    2017-03-15

    On the basis of measurements, such as field emission scanning electron microscope, UV-Vis diffuse reflectance spectra, X-ray diffraction, electron paramagnetic resonance, photoluminescence spectra, and photocurrent measurements, the roles of anatase TiO2 sheet on synthesizing Ti(3+) self-doped mixed phase TiO2 nanosheets (doped TiO2 (A/R, TiO2 (A))) and on improving the performance for photocatalytic CO2 reduction were explored systematically. High surface area anatase TiO2 nanosheets (TiO2 (A)) as a substrate, structure directing agent, and inhibitor, mediated the synthesis of Ti(3+) self-doped mixed phase TiO2 nanosheets. Addition of TiO2 (A) significantly improved not only visible light absorption of doped TiO2 (A/R, TiO2 (A)), but also the efficiency of photo-excited charges separations due to the existence of interfacial regions of anatase-rutile TiO2 junctions. Finally, a possible mechanism for interfacial charge transfer at the anatase-rutile TiO2 interface and for photocatalytic CO2 reduction over Pt loaded doped TiO2 (A/R, TiO2 (A)) were proposed. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Microscopy and supporting data for osteoblast integration within an electrospun fibrous network

    Directory of Open Access Journals (Sweden)

    Urszula Stachewicz

    2015-12-01

    Full Text Available This data article contains data related to the research article entitled “3D imaging of cell interactions with electrospun PLGA nanofiber membranes for bone regeneration” by Stachewicz et al. [1]. In this paper we include additional data showing degradation analysis of poly(d,l-lactide-co-glycolide acid (PLGA electrospun fibers in medium and air using fiber diameter distribution histograms. We also describe the steps used in “slice and view” tomography techniques with focused ion beam (FIB microscopy and scanning electron microscopy (SEM and detail the image analysis to obtain 3D reconstruction of osteoblast cell integration with electrospun network of fibers. Further supporting data and detailed information on the quantification of cell growth within the electrospun nanofiber membranes is provided.

  1. Polyamic Acid Nanofibers Produced by Needleless Electrospinning

    Directory of Open Access Journals (Sweden)

    Oldrich Jirsak

    2010-01-01

    Full Text Available The polyimide precursor (polyamic acid produced of 4,4′-oxydiphthalic anhydride and 4,4′-oxydianiline was electrospun using needleless electrospinning method. Nonwoven layers consisting of submicron fibers with diameters in the range about 143–470 nm on the polypropylene spunbond supporting web were produced. Filtration properties of these nanofiber layers on the highly permeable polypropylene support—namely filtration effectivity and pressure drop—were evaluated. Consequently, these polyamic acid fibers were heated to receive polyimide nanofibers. The imidization process has been studied using IR spectroscopy. Some comparisons with the chemically identical polyimide prepared as the film were made.

  2. Electrospun Graphene-TiO2 Nanocomposite Fiber Mats for High Efficient Electron Conductor in Photovoltaic Devices

    Science.gov (United States)

    Zhang, Xiang; Truong Nguyen, Son; Tien Nguyen, Hoa; Duong, Hai Minh; Ramakrishna, Seeram

    2012-02-01

    The photovoltaic performance of dye-sensitized solar cells can be rationally improved by incorporating graphene nanosheet in n-type TiO2 semiconductor because of the high electron mobility of graphene. However, the incorporation of graphene into TiO2 semiconductor to achieve high performance is still challenging. We report a facile method to synthesize 1 dimensional graphene-TiO2 nanofibers by chemical exfoliation and electrospinning. Functionalized graphene was prepared from commercial graphite using a modified Hummers method, following by sonication and reduction with NaBH4. The effect of oxidation time during chemical exfoliation process, the content of graphene during electrospinning and proper film thickness of graphene-TiO2 nanofibers mat with respect to power conversion efficiency was investigated. Compared to TiO2 film, the graphene-TiO2 nanofibers mat significantly improves the conductivity. Further improvements could be expected by optimizing electron diffusion distance and fabrication process.

  3. Enhanced cell mitochondrial activity using electrospun nanofibers

    CSIR Research Space (South Africa)

    Jacobs, V

    2015-06-01

    Full Text Available technology and surgical applications. Proc Instn Mech Eng Part H - J Eng Med. 1998; 212: 101-111. 16. Barbanti, S.H.; Zavaglia, C.A.C. & Duek, E.A.R. Polímeros bioreabsorvíveis na engenharia de tecidos. Polímeros: Ciência e Tecnologia. 2005; 15: 13-21. 17...

  4. Nanocomposite Electrospun Nanofiber Membranes for Environmental Remediation

    Directory of Open Access Journals (Sweden)

    Shahin Homaeigohar

    2014-02-01

    Full Text Available Rapid worldwide industrialization and population growth is going to lead to an extensive environmental pollution. Therefore, so many people are currently suffering from the water shortage induced by the respective pollution, as well as poor air quality and a huge fund is wasted in the world each year due to the relevant problems. Environmental remediation necessitates implementation of novel materials and technologies, which are cost and energy efficient. Nanomaterials, with their unique chemical and physical properties, are an optimum solution. Accordingly, there is a strong motivation in seeking nano-based approaches for alleviation of environmental problems in an energy efficient, thereby, inexpensive manner. Thanks to a high porosity and surface area presenting an extraordinary permeability (thereby an energy efficiency and selectivity, respectively, nanofibrous membranes are a desirable candidate. Their functionality and applicability is even promoted when adopting a nanocomposite strategy. In this case, specific nanofillers, such as metal oxides, carbon nanotubes, precious metals, and smart biological agents, are incorporated either during electrospinning or in the post-processing. Moreover, to meet operational requirements, e.g., to enhance mechanical stability, decrease of pressure drop, etc., nanofibrous membranes are backed by a microfibrous non-woven forming a hybrid membrane. The novel generation of nanocomposite/hybrid nanofibrous membranes can perform extraordinarily well in environmental remediation and control. This reality justifies authoring of this review paper.

  5. Nanocomposite Electrospun Nanofiber Membranes for Environmental Remediation

    OpenAIRE

    Shahin Homaeigohar; Mady Elbahri

    2014-01-01

    Rapid worldwide industrialization and population growth is going to lead to an extensive environmental pollution. Therefore, so many people are currently suffering from the water shortage induced by the respective pollution, as well as poor air quality and a huge fund is wasted in the world each year due to the relevant problems. Environmental remediation necessitates implementation of novel materials and technologies, which are cost and energy efficient. Nanomaterials, with their unique chem...

  6. Electrospun composites of PHBV/pearl powder for bone repairing

    Directory of Open Access Journals (Sweden)

    Jingjing Bai

    2015-08-01

    Full Text Available Electrospun fiber has highly structural similarity with natural bone extracelluar matrix (ECM. Many researches about fabricating organic–inorganic composite materials have been carried out in order to mimic the natural composition of bone and enhance the biocompatibility of materials. In this work, pearl powder was added to the poly (3-hydroxybutyrate-co-3-hydroxyvalerate (PHBV and the composite nanofiber scaffold was prepared by electrospinning. Mineralization ability of the composite scaffolds can be evaluated by analyzing hydroxyapatite (HA formation on the surface of nanofiber scaffolds. The obtained composite nanofiber scaffolds showed an enhanced mineralization capacity due to incorporation of pearl powder. The HA formed amount of the composite scaffolds was raised as the increase of pearl powder in composite scaffolds. Therefore, the prepared PHBV/pearl composite nanofiber scaffolds would be a promising candidate as an osteoconductive composite material for bone repairing.

  7. Ceramic Nanofibers by Electrospinning of Precursor Polymers

    Science.gov (United States)

    2008-07-29

    emission scanning electron microscopy (FE-SEM) (1 band 1c). As shown, bulk electrospun SiC nanofibers synthesis is possible (1a). FE-SEM and...comparison, commercial SiC nanoparticles have a native oxide layer of at least 100 nm. Thus, there is a lower limit to the fiber diameters produced by... antimony n-butoxide to form aluminum antimonide, and indium methoxyethoxide and antimony n- butoxide to form indium antimonide and a variety of nitride

  8. High pressure synthesis of amorphous TiO2 nanotubes

    Directory of Open Access Journals (Sweden)

    Quanjun Li

    2015-09-01

    Full Text Available Amorphous TiO2 nanotubes with diameters of 8-10 nm and length of several nanometers were synthesized by high pressure treatment of anatase TiO2 nanotubes. The structural phase transitions of anatase TiO2 nanotubes were investigated by using in-situ high-pressure synchrotron X-ray diffraction (XRD method. The starting anatase structure is stable up to ∼20GPa, and transforms into a high-density amorphous (HDA form at higher pressure. Pressure-modified high- to low-density transition was observed in the amorphous form upon decompression. The pressure-induced amorphization and polyamorphism are in good agreement with the previous results in ultrafine TiO2 nanoparticles and nanoribbons. The relationship between the LDA form and α-PbO2 phase was revealed by high-resolution transmission electron microscopy (HRTEM study. In addition, the bulk modulus (B0 = 158 GPa of the anatase TiO2 nanotubes is smaller than those of the corresponding bulks and nanoparticles (180-240 GPa. We suggest that the unique open-ended nanotube morphology and nanosize play important roles in the high pressure phase transition of TiO2 nanotubes.

  9. UV-responsive polyvinyl alcohol nanofibers prepared by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Khatri, Zeeshan, E-mail: zeeshan.khatri@faculty.muet.edu.pk [Department of Textile Engineering, Mehran University of Engineering and Technology, Jamshoro 76062 (Pakistan); Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan); Ali, Shamshad [Department of Textile Engineering, Mehran University of Engineering and Technology, Jamshoro 76062 (Pakistan); Department of Organic and Nano Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Khatri, Imran [Department of Entomology, Sindh Agriculture University, Tandojam (Pakistan); Mayakrishnan, Gopiraman [Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan); Kim, Seong Hun [Department of Organic and Nano Engineering, Hanyang University, 17 Haengdang-dong, Seongdong-gu, Seoul 133-791 (Korea, Republic of); Kim, Ick-Soo, E-mail: kim@shinshu-u.ac.jp [Nano Fusion Technology Research Lab, Division of Frontier Fibers, Institute for Fiber Engineering (IFES), Interdisciplinary Cluster for Cutting Edge Research (ICCER), Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan)

    2015-07-01

    Graphical abstract: - Highlights: • UV responsive PVA nanofibers were prepared via electrospinning. • Quick response codes were recorded multiple times on UV responsive nanofibers. • The rate of photo-coloration was found faster than the rate of photo-reversibility. - Abstract: We report UV-responsive polyvinyl alcohol (PVA) nanofibers for potential application for recording and erasing quick response (QR) codes. We incorporate 1′-3′-dihydro-8-methoxy-1′,3′,3′-trimethyl-6-nitrospiro [2H-1-benzopyran-2,2′-(2H)-indole] (indole) and,3-dihydro-1,3,3-trimethylspiro [2H-indole-2,3′-[3H] phenanthr [9,10-b] (1,4) oxazine] (oxazine) into PVA polymer matrix via electrospinning technique. The resultant nanofibers were measured for recording–erasing, photo-coloration and thermal reversibility. The rate of photo-coloration of PVA–indole nanofibers was five times higher than the PVA–oxazine nanofibers, whereas the thermal reversibility found to be more than twice as fast as PVA–oxazine nanofibers. Results showed that the resultant nanofibers have very good capability of recording QR codes multiple times. The FTIR spectroscopy and SEM were employed to characterize the electrospun nanofibers. The UV-responsive PVA nanofibers have great potentials as a light-driven nanomaterials incorporated within sensors, sensitive displays and in optical devices such as erasable and rewritable optical storage.

  10. Nanofiber membrane-electrode-assembly and method of fabricating same

    Energy Technology Data Exchange (ETDEWEB)

    Pintauro, Peter N.; Ballengee, Jason; Brodt, Matthew

    2016-02-02

    In one aspect of the present invention, a fuel cell membrane-electrode-assembly (MEA) has an anode electrode, a cathode electrode, and a membrane disposed between the anode electrode and the cathode electrode. At least one of the anode electrode, the cathode electrode and the membrane is formed of electrospun nanofibers.

  11. TiO2-ITO and TiO2-ZnO nanocomposites: application on water treatment

    Directory of Open Access Journals (Sweden)

    Bessais B.

    2012-06-01

    Full Text Available One of the most promising ideas to enhance the photocatalytic efficiency of the TiO2 is to couple this photocatalyst with other semiconductors. In this work, we report on the development of photo-catalytic properties of two types of composites based on TiO2 – ITO (Indium Tin Oxide and TiO2 – ZnO deposited on conventional ceramic substrates. The samples were characterized by X-ray diffraction (XRD and transmission Electron Microscopy (TEM. The photo-catalytic test was carried out under UV light in order to reduce/oxidize a typical textile dye (Cibacron Yellow. The experiment was carried out in a bench scale reactor using a solution having a known initial dye concentration. After optimization, we found that both nanocomposites exhibit better photocatalytic activity compared to the standard photocatalyst P25 TiO2.

  12. Selective aerobic oxidation mediated by TiO(2) photocatalysis.

    Science.gov (United States)

    Lang, Xianjun; Ma, Wanhong; Chen, Chuncheng; Ji, Hongwei; Zhao, Jincai

    2014-02-18

    TiO2 is one of the most studied metal oxide photocatalysts and has unparal-leled efficiency and stability. This cheap, abundant, and non-toxic material has the potential to address future environmental and energy concerns. Understanding about the photoinduced interfacial redox events on TiO2 could have profound effect on the degradation of organic pollutants, splitting of H2O into H2 and O2, and selective redox organic transformations. Scientists traditionally accept that for a semiconductor photocatalyst such as TiO2 under the illumination of light with energy larger than its band gap, two photocarriers will be created to carry out their independent reduction and oxidation processes. However, our recent discoveries indicate that it is the concerted rather than independent effect of both photocarriers of valence band hole (hvb(+)) and conduction band electron (ecb(-)) that dictate the product formation during interfacial oxidation event mediated by TiO2 photocatalysis. In this Account, we describe our recent findings on the selective oxidation of organic substrates with O2 mediated by TiO2 photocatalysis. The transfer of O-atoms from O2 to the corresponding products dominates the selective oxidation of alcohols, amines, and alkanes mediated by TiO2 photocatalysis. We ascribe this to the concerted effect of both hvb(+) and ecb(-) of TiO2 in contribution to the oxidation products. These findings imply that O2 plays a unique role in its transfer into the products rather than independent role of ecb(-) scavenger. More importantly, ecb(-) plays a crucial role to ensure the high selectivity for the oxygenation of organic substrates. We can also use the half reactions such as those of the conduction band electron of TiO2 for efficient oxidation reactions with O2. To this end, efficient selective oxidation of organic substrates such as alcohols, amines, and aromatic alkanes with O2 mediated by TiO2 photocatalysis under visible light irradiation has been achieved. In summary, the concerted effect of hvb(+) and ecb(-) to implement one oxidation event could pave the way for selective oxofunctionalization of organic substrates with O2 by metal oxide photocatalysis. Furthermore, it could also deepen our understanding on the role of O2 and the elusive nature of oxygen species at the interface of TiO2, which, in turn, could shed new light on avant-garde photocatalytic selective redox processes in addressing the energy and environmental challenges of the future.

  13. Genotoxicity of inhaled nanosized TiO(2) in mice.

    Science.gov (United States)

    Lindberg, Hanna K; Falck, Ghita C-M; Catalán, Julia; Koivisto, Antti J; Suhonen, Satu; Järventaus, Hilkka; Rossi, Elina M; Nykäsenoja, Heli; Peltonen, Yrjö; Moreno, Carlos; Alenius, Harri; Tuomi, Timo; Savolainen, Kai M; Norppa, Hannu

    2012-06-14

    In vitro studies have suggested that nanosized titanium dioxide (TiO(2)) is genotoxic. The significance of these findings with respect to in vivo effects is unclear, as few in vivo studies on TiO(2) genotoxicity exist. Recently, nanosized TiO(2) administered in drinking water was reported to increase, e.g., micronuclei (MN) in peripheral blood polychromatic erythrocytes (PCEs) and DNA damage in leukocytes. Induction of micronuclei in mouse PCEs was earlier also described for pigment-grade TiO(2) administered intraperitoneally. The apparent systemic genotoxic effects have been suggested to reflect secondary genotoxicity of TiO(2) due to inflammation. However, a recent study suggested that induction of DNA damage in mouse bronchoalveolar lavage (BAL) cells after intratracheal instillation of nanosized or fine TiO(2) is independent of inflammation. We examined here, if inhalation of freshly generated nanosized TiO(2) (74% anatase, 26% brookite; 5 days, 4 h/day) at 0.8, 7.2, and (the highest concentration allowing stable aerosol production) 28.5 mg/m(3) could induce genotoxic effects in C57BL/6J mice locally in the lungs or systematically in peripheral PCEs. DNA damage was assessed by the comet assay in lung epithelial alveolar type II and Clara cells sampled immediately following the exposure. MN were analyzed by acridine orange staining in blood PCEs collected 48 h after the last exposure. A dose-dependent deposition of Ti in lung tissue was seen. Although the highest exposure level produced a clear increase in neutrophils in BAL fluid, indicating an inflammatory effect, no significant effect on the level of DNA damage in lung epithelial cells or micronuclei in PCEs was observed, suggesting no genotoxic effects by the 5-day inhalation exposure to nanosized TiO(2) anatase. Our inhalation exposure resulted in much lower systemic TiO(2) doses than the previous oral and intraperitoneal treatments, and lung epithelial cells probably received considerably less TiO(2) than BAL cells in the earlier intratracheal study. Copyright © 2011 Elsevier B.V. All rights reserved.

  14. Lithium insertion in nanostructured TiO(2)(B) architectures.

    Science.gov (United States)

    Dylla, Anthony G; Henkelman, Graeme; Stevenson, Keith J

    2013-05-21

    Electric vehicles and grid storage devices have potentialto become feasible alternatives to current technology, but only if scientists can develop energy storage materials that offer high capacity and high rate capabilities. Chemists have studied anatase, rutile, brookite and TiO2(B) (bronze) in both bulk and nanostructured forms as potential Li-ion battery anodes. In most cases, the specific capacity and rate of lithiation and delithiation increases as the materials are nanostructured. Scientists have explained these enhancements in terms of higher surface areas, shorter Li(+) diffusion paths and different surface energies for nanostructured materials allowing for more facile lithiation and delithiation. Of the most studied polymorphs, nanostructured TiO2(B) has the highest capacity with promising high rate capabilities. TiO2(B) is able to accommodate 1 Li(+) per Ti, giving a capacity of 335 mAh/g for nanotubular and nanoparticulate TiO2(B). The TiO2(B) polymorph, discovered in 1980 by Marchand and co-workers, has been the focus of many recent studies regarding high power and high capacity anode materials with potential applications for electric vehicles and grid storage. This is due to the material's stability over multiple cycles, safer lithiation potential relative to graphite, reasonable capacity, high rate capability, nontoxicity, and low cost (Bruce, P. G.; Scrosati, B.; Tarascon, J.-M. Nanomaterials for Rechargeable Lithium Batteries. Angew. Chem., Int. Ed.2008, 47, 2930-2946). One of the most interesting properties of TiO2(B) is that both bulk and nanostructured forms lithiate and delithiate through a surface redox or pseudocapacitive charging mechanism, giving rise to stable high rate charge/discharge capabilities in the case of nanostructured TiO2(B). When other polymorphs of TiO2 are nanostructured, they still mainly intercalate lithium through a bulk diffusion-controlled mechanism. TiO2(B) has a unique open crystal structure and low energy Li(+) pathways from surface to subsurface sites, which many chemists believe to contribute to the pseudocapacitive charging. Several disadvantages exist as well. TiO2(B), and titania in general, suffers from poor electronic and ionic conductivity. Nanostructured TiO2(B) also exhibits significant irreversible capacity loss (ICL) upon first discharge (lithiation). Nanostructuring TiO2(B) can help alleviate problems with poor ionic conductivity by shortening lithium diffusion pathways. Unfortunately, this also increases the likelihood of severe first discharge ICL due to reactive Ti-OH and Ti-O surface sites that can cause unwanted electrolyte degradation and irreversible trapping of Li(+). Nanostructuring also results in lowered volumetric energy density, which could be a considerable problem for mobile applications. We will also discuss these problems and proposed solutions. Scientists have synthesized TiO2(B) in a variety of nanostructures including nanowires, nanotubes, nanoparticles, mesoporous-ordered nanostructures, and nanosheets. Many of these structures exhibit enhanced Li(+) diffusion kinetics and increased specific capacities compared to bulk material, and thus warrant investigation on how nanostructuring influences lithiation behavior. This Account will focus on these influences from both experimental and theoretical perspectives. We will discuss the surface charging mechanism that gives rise to the increased lithiation and delithiation kinetics for TiO2(B), along with the influence of dimensional confinement of the nanoarchitectures, and how nanostructuring can change the lithiation mechanism considerably.

  15. A Pendulum-Like Motion of Nanofiber Gel Actuator Synchronized with External Periodic pH Oscillation

    Directory of Open Access Journals (Sweden)

    Shuji Hasimoto

    2011-02-01

    Full Text Available In this study, we succeeded in manufacturing a novel nanofiber hydrogel actuator that caused a bending and stretching motion synchronized with external pH oscillation, based on a bromate/sulfite/ferrocyanide reaction. The novel nanofiber gel actuator was composed of electrospun nanofibers synthesized by copolymerizing acrylic acid and hydrophobic butyl methacrylate as a solubility control site. By changing the electrospinning flow rate, the nanofiber gel actuator introduced an anisotropic internal structure into the gel. Therefore, the unsymmetrical motion of the nanofiber actuator was generated.

  16. Tissue engineering scaffolds electrospun from cotton cellulose.

    Science.gov (United States)

    He, Xu; Cheng, Long; Zhang, Ximu; Xiao, Qiang; Zhang, Wei; Lu, Canhui

    2015-01-22

    Nonwovens of cellulose nanofibers were fabricated by electrospinning of cotton cellulose in its LiCl/DMAc solution. The key factors associated with the electrospinning process, including the intrinsic properties of cellulose solutions, the rotating speed of collector and the applied voltage, were systematically investigated. XRD data indicated the electrospun nanofibers were almost amorphous. When increasing the rotating speed of the collector, preferential alignment of fibers along the drawing direction and improved molecular orientation were revealed by scanning electron microscope and polarized FTIR, respectively. Tensile tests indicated the strength of the nonwovens along the orientation direction could be largely improved when collected at a higher speed. In light of the excellent biocompatibility and biodegradability as well as their unique porous structure, the nonwovens were further assessed as potential tissue engineering scaffolds. Cell culture experiments demonstrated human dental follicle cells could proliferate rapidly not only on the surface but also in the entire scaffold. Copyright © 2014 Elsevier Ltd. All rights reserved.

  17. Au-loaded TiO2 and Ag-loaded TiO2 synthesized by modified sol-gel/impregnation method as photocatalysts

    Science.gov (United States)

    Ninsonti, Hathaithip; Sriwichai, Saengrawee; Wetchakun, Natda; Kangwansupamonkon, Wiyong; Phanichphant, Sukon

    2016-02-01

    In this work, Au-loaded TiO2 and Ag-loaded TiO2 nanoparticles were synthesized by modified sol-gel method together with impregnation method. The samples were characterized by their physicochemical properties using X-ray diffraction (XRD) and X-ray photoelectron spectroscopy in order to obtain the correlation between structure and photocatalytic properties. XRD results indicated unloaded TiO2, Au-loaded TiO2 and Ag-loaded TiO2 nanoparticles were all in the anatase phase with average crystallite size in the range of 10-13 nm. In addition, XPS analysis confirmed the presence of Au and Ag elements in Au-loaded TiO2 and Ag-loaded TiO2 nanoparticles, respectively. The photocatalytic activities of TiO2, Au-loaded TiO2 and Ag-loaded TiO2 nanoparticles were evaluated through the mineralization of formic acid under UV-light illumination. The results showed that Au-loading and Ag-loading could effectively improve the photocatalytic activities of TiO2. Furthermore, Au-loaded TiO2 exhibited a higher photocatalytic activity than Ag-loaded TiO2.

  18. Investigation of drug release from paclitaxel loaded polylactic acid nanofibers

    Directory of Open Access Journals (Sweden)

    Amir Doustgani

    2016-07-01

    Full Text Available Objective(s: In this study, drug loaded electrospun nanofibrous mats were prepared and drug release and mechanism from prepared nanofibers were investigated.  Materials and Methods: Paclitaxel (PTX loaded polylactic acid (PLA nanofibers were prepared by electrospinning. The effects of process parameters, such as PTX concentration, tip to collector distance, voltage, temperature and flow rate on the mean diameter of electrospun PTX loaded PLA nanofibers were investigated. Scanning electron microscopy (SEM was used to investigate the fiber morphology and mean fiber diameter of prepared nanofibers. Response surface methodology was used to model the average diameter of electrospun PLA/PTX nanofibers. Results: The predicted fiber diameter was in good agreement with the experimental result. In Vitro drug release in phosphate buffer solution (PBS and acetate buffer for the produced samples showed that diffusion is the dominant drug release mechanism for PTX loaded ubers. Conclusion: Electrospinning was shown to be very promising approach to the formulation of Paclitaxel in order to enhance its release in a sustained and prolonged manner.

  19. Environmental remediation and superhydrophilicity of ultrafine antibacterial tungsten oxide-based nanofibers under visible light source

    Energy Technology Data Exchange (ETDEWEB)

    Srisitthiratkul, Chutima; Yaipimai, Wittaya [Nano Functional Textile Laboratory, National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), 111 Thailand Science Park, Phahonyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 (Thailand); Intasanta, Varol, E-mail: varol@nanotec.or.th [Nano Functional Textile Laboratory, National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA), 111 Thailand Science Park, Phahonyothin Rd., Klong 1, Klong Luang, Pathumthani 12120 (Thailand)

    2012-10-15

    Graphical abstract: Nanosilver-decorated WO{sub 3} photocatalytic nanofibers are antibacterial and superhydrophilic under a visible light source. Highlights: Black-Right-Pointing-Pointer Deposition of nanosilver onto electrospun WO{sub 3} nanofibers' surface was done exploiting visible or UV light driven photoreduction of silver ion. Black-Right-Pointing-Pointer Nanofibers showed antibacterial characteristics. Black-Right-Pointing-Pointer Nanofibers degraded a model toxin effectively. Black-Right-Pointing-Pointer Nanofibers showed superhydrophilicity under a visible light source. - Abstract: Fabrication of nanosilver-decorated WO{sub 3} nanofibers was successfully performed. First, deposition of nanosilver onto electrospun WO{sub 3} nanofibers' surface was done via photoreduction of silver ion under visible or UV light. The resulting hybrid nanofibers not only revealed antibacterial characteristics but also maintained their photocatalytic performance towards methylene blue decomposition. Unexpectedly, the nanofibrous layers prepared from these nanofibers showed superhydrophilicity under a visible light source. The nanofibers might be advantageous in environmental and hygienic nanofiltration under natural light sources, where the self-cleaning characteristics could be valuable in maintenance processes.

  20. Collagen nanofiber containing silver nanoparticles for improved wound-healing applications.

    Science.gov (United States)

    Rath, Goutam; Hussain, Taqadus; Chauhan, Gaurav; Garg, Tarun; Goyal, Amit Kumar

    2016-01-01

    Electrospun nanofibers showing great promise for fabricating nanostructured materials might help to improve the quality of wound care. The present study aimed to investigate the wound-healing potential of collagen nanofiber mats containing silver nanoparticles. Si