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Sample records for electrospun fiber mats

  1. Tough Stretchable Physically-Cross-linked Electrospun Hydrogel Fiber Mats.

    PubMed

    Yang, Yiming; Wang, Chao; Wiener, Clinton G; Hao, Jinkun; Shatas, Sophia; Weiss, R A; Vogt, Bryan D

    2016-09-01

    Nature uses supramolecular interactions and hierarchical structures to produce water-rich materials with combinations of properties that are challenging to obtain in synthetic systems. Here, we demonstrate hierarchical supramolecular hydrogels from electrospun, self-associated copolymers with unprecedented elongation and toughness for high porosity hydrogels. Hydrophobic association of perfluoronated comonomers provides the physical cross-links for these hydrogels based on copolymers of dimethyl acrylamide and 2-(N-ethylperfluorooctane sulfonamido)ethyl methacrylate (FOSM). Intriguingly, the hydrogel fiber mats show an enhancement in toughness in comparison to compression molded bulk hydrogels. This difference is attributed to the size distribution of the hydrophobic aggregates where narrowing the distribution in the electrospun material enhances the toughness of the hydrogel. These hydrogel fiber mats exhibit extensibility more than double that of the bulk hydrogel and a comparable modulus despite the porosity of the fiber mat leading to >25 wt % increase in water content. PMID:27548013

  2. Hydrogel–Electrospun Fiber Mat Composite Coatings for Neural Prostheses

    PubMed Central

    Han, Ning; Rao, Shreyas S.; Johnson, Jed; Parikh, Kunal S.; Bradley, Patrick A.; Lannutti, John J.; Winter, Jessica O.

    2011-01-01

    Achieving stable, long-term performance of implanted neural prosthetic devices has been challenging because of implantation related neuron loss and a foreign body response that results in encapsulating glial scar formation. To improve neuron–prosthesis integration and form chronic, stable interfaces, we investigated the potential of neurotrophin-eluting hydrogel–electrospun fiber mat (EFM) composite coatings. In particular, poly(ethylene glycol)-poly(ε-caprolactone) (PEGPCL) hydrogel–poly(ε-caprolactone) EFM composites were applied as coatings for multielectrode arrays. Coatings were stable and persisted on electrode surfaces for over 1 month under an agarose gel tissue phantom and over 9 months in a PBS immersion bath. To demonstrate drug release, a neurotrophin, nerve growth factor (NGF), was loaded in the PEGPCL hydrogel layer, and coating cytotoxicity and sustained NGF release were evaluated using a PC12 cell culture model. Quantitative MTT assays showed that these coatings had no significant toxicity toward PC12 cells, and neurite extension at day 7 and 14 confirmed sustained release of NGF at biologically significant concentrations for at least 2 weeks. Our results demonstrate that hydrogel–EFM composite materials can be applied to neural prostheses to improve neuron–electrode proximity and enhance long-term device performance and function. PMID:21441993

  3. Characterization and Modification of Electrospun Fiber Mats for Use in Composite Proton Exchange Membranes

    NASA Astrophysics Data System (ADS)

    Mannarino, Matthew Marchand

    Electrostatic fiber formation, or electrospinning, offers a particularly simple and robust method to create polymeric nanofibers of various sizes and morphologies. In electrospinning, a viscoelastic fluid is charged so that a liquid jet is ejected from the surface of the fluid (typically in the form of a drop supplied by a needle or spinneret) and collected on a grounded plate, creating a nonwoven fiber mat. Modification of the diameter of the fibers as well as the porosity, specific surface area, and mechanical properties of the mat allows one to tailor electrospun mats for specific applications. Despite the widespread and rapidly growing use of electrospinning in the fabrication of novel nanomaterials, there are no simple, universal methods of predicting, a priori, the properties of electrospun fibers from knowledge of the polymer solution properties and electrospinning operating conditions alone. Changing a single fluid or processing parameter can affect the jet and fiber formation through several mechanisms. For example, using a different solvent can change several properties of the electrospinning fluid, such as the dielectric constant, conductivity, surface tension, and solute-solvent interaction. The work in this thesis seeks to develop a simple relation for predicting terminal jet diameter during electrospinning, which accounts for solution viscoelasticity as well as solution conductivity and operating parameters that can be easily measured and controlled. The mechanical and tribological properties of electrospun fiber mats are of paramount importance to their utility as components in a variety of applications. Although some mechanical properties of these mats have been investigated previously, reports of their tribological properties are essentially nonexistent. In this thesis, electrospun nanofiber mats of poly(trimethyl hexamethylene terephthalamide) (PA 6(3)T) and poly(hexamethylene adipamide) (PA 6,6) are characterized mechanically and tribologically

  4. Interaction of gelatin with polyenes modulates antifungal activity and biocompatibility of electrospun fiber mats

    PubMed Central

    Lakshminarayanan, Rajamani; Sridhar, Radhakrishnan; Loh, Xian Jun; Nandhakumar, Muruganantham; Barathi, Veluchamy Amutha; Kalaipriya, Madhaiyan; Kwan, Jia Lin; Liu, Shou Ping; Beuerman, Roger Wilmer; Ramakrishna, Seeram

    2014-01-01

    Topical application of antifungals does not have predictable or well-controlled release characteristics and requires reapplication to achieve therapeutic local concentration in a reasonable time period. In this article, the efficacy of five different US Food and Drug Administration-approved antifungal-loaded (amphotericin B, natamycin, terbinafine, fluconazole, and itraconazole) electrospun gelatin fiber mats were compared. Morphological studies show that incorporation of polyenes resulted in a two-fold increase in fiber diameter and the mats inhibit the growth of yeasts and filamentous fungal pathogens. Terbinafine-loaded mats were effective against three filamentous fungal species. Among the two azole antifungals compared, the itraconazole-loaded mat was potent against Aspergillus strains. However, activity loss was observed for fluconazole-loaded mats against all of the test organisms. The polyene-loaded mats displayed rapid candidacidal activities as well. Biophysical and rheological measurements indicate strong interactions between polyene antifungals and gelatin matrix. As a result, the polyenes stabilized the triple helical conformation of gelatin and the presence of gelatin decreased the hemolytic activity of polyenes. The polyene-loaded fiber mats were noncytotoxic to primary human corneal and sclera fibroblasts. The reduction of toxicity with complete retention of activity of the polyene antifungal-loaded gelatin fiber mats can provide new opportunities in the management of superficial skin infections. PMID:24920895

  5. Morphology, release characteristics, and antimicrobial effect of nisin-loaded electrospun gelatin fiber mat.

    PubMed

    Dheraprasart, Chanuttaporn; Rengpipat, Sirirat; Supaphol, Pitt; Tattiyakul, Jirarat

    2009-11-01

    Gelatin electrospun (e-spun) fiber mats containing nisin were produced by electrostatic spinning of gelatin-nisin in 70% (vol/vol) acetic acid aqueous solutions. Varying nisin loading concentration (0 to 3% [wt/wt]) did not affect the fiber average diameter, whereas increasing gelatin concentration from 20 to 24% (wt/vol) caused an increase in the average diameter. All nisin-loaded gelatin e-spun fiber mats demonstrated inhibition against Lactobacillus plantarum TISTR 850. However, all fiber mats were fragile and easily dissolved in water. Cross-linking by saturated glutaraldehyde vapor at 37 degrees C for 5 min was done to strengthen the mat. Tensile strength, Young's modulus, and elongation of the cross-linked gelatin-nisin e-spun fiber mats varied in the range of 2.6 to 20.3 MPa, 163 to 966 MPa, and 1.7 to 5.9% , respectively. Cross-linking did not affect the mat's inhibition activity against L. plantarum TISTR 850. Nisin retention in cross-linked antimicrobial gelatin e-spun fiber mats was in the range of 1.0 to 1.22% . Increasing temperature caused an increase in nisin release, but increasing water activity did not cause a significant difference in nisin release over 50 h. After storage at 25 degrees C for 5 months, the antimicrobial gelatin e-spun fiber mat still showed inhibition against L. plantarum TISTR 850. The mats also inhibited the growth of Staphylococcus aureus and Listeria monocytogenes but not Salmonella Typhimurium. PMID:19903391

  6. Ultrafast and fast bioerodible electrospun fiber mats for topical delivery of a hydrophilic peptide.

    PubMed

    Macri, Lauren K; Sheihet, Larisa; Singer, Adam J; Kohn, Joachim; Clark, Richard A F

    2012-08-10

    Biodegradable polymers that provide localized controlled delivery of therapeutics within hours to days may have an impact on the topical treatment of skin burns. Here we report for the first time the utility of tyrosine-derived polycarbonate terpolymer electrospun fiber mats as tunable drug delivery matrices. "Ultrafast" (<24 h) and "fast"-eroding (<7 days) terpolymers were identified. The degradation kinetics of both terpolymers was similar (<20% of initial molecular weight after 7 days), while erosion was significantly different (<1 and 4 days for ultrafast and fast fibers, respectively). To assess the delivery kinetics, a hydrophilic peptide (P12) was incorporated into the fibers as a model drug. The tunability of polymer composition and its control over release kinetics resulted in significantly different P12 delivery timeframes: total of 9 h ("ultrafast" via polymer erosion) and 4 days ("fast" via diffusion). The biocompatibility of these fibers was confirmed in a porcine excisional wound model by the (i) lack of inflammatory response to the terpolymers and their degradation products, and (ii) normal progression of healing evaluated for 28 days. These results suggest that electrospun tyrosine-derived fibers offer the potential for topical therapies that require ultrafast or fast dose-controlled delivery of the therapeutic.

  7. Electrospun fiber mats containing shikonin and derivatives with potential biomedical applications.

    PubMed

    Kontogiannopoulos, Konstantinos N; Assimopoulou, Andreana N; Tsivintzelis, Ioannis; Panayiotou, Costas; Papageorgiou, Vassilios P

    2011-05-16

    Alkannin, shikonin (A/S) and their derivatives are naturally occurring hydroxynaphthoquinones with a well-established spectrum of wound healing, antimicrobial, anti-inflammatory, antioxidant and antitumor activity. Clinical studies over the years revealed that A/S derivatives-based wound healing preparations (such as HELIXDERM(®)) are among a very small group of therapeutics that modulate both the inflammatory and proliferative phases of wound healing and present significant tissue regenerative activity. The purpose of the present work was to combine the biological properties of A/S and the advantages of electrospun meshes to prepare a potent topical/transdermal biomaterial for A/S. Four biocompatible polymers (cellulose acetate, poly(L-lactide), poly(lactide-co-glycolide) LA/GA:50/50 and 75/25) were used for the first time, to produce electrospun fiber mats containing either shikonin or A/S mixture in various amounts. Both drugs were effectively loaded into the above biomaterials. The incorporation of drugs did not considerably affect fibers morphology and their mean diameter size varied from 315 to 670 nm. High drug entrapment efficiencies (ranged from 74% to 95%) and appropriate release profiles were achieved, that render these fibers as potential A/S topical/transdermal wound healing dressings. Given the multifunctional activity of the natural products alkannins and shikonins, their consideration as bioactive constituents for tissue engineering scaffolds seems a promising strategy for repairing and regenerating tissues and mainly skin.

  8. Preparation of electrospun fiber mats using siloxane-containing vaterite and biodegradable polymer hybrids for bone regeneration.

    PubMed

    Fujikura, Kie; Lin, Sen; Nakamura, Jin; Obata, Akiko; Kasuga, Toshihiro

    2013-11-01

    An electrospun fiber mat using a new composite consisting of siloxane-containing vaterite (SiV) and poly(lactic-co-glycolic acid) (PLGA) (denoted by SiPLGVH) was prepared with the aim of applying it as a membrane for use in a guided bone regeneration (GBR) system. Another electrospun fiber mat using a previously described composite consisting of SiV and poly(L-lactic acid) (denoted by SiPVH) was also prepared as a comparative sample. SiPLG VH fiber mats showed superior results in terms of mechanical tensile properties and cellular behavior. Their elongation before failure was about eight times higher than that of SiPVH. The numbers of osteoblast-like cells that proliferated on the SiPLGVH fiber mats, regardless of the hydroxyapatite coating, were comparable to that of SiPVH. The cells spread more, two dimensionally, on the SiPLGVH fiber mats, since the pores between fibers were narrowed down because of swelling of the PLGA matrix during cell culture. This two-dimensional cellular proliferation quality on the SiPLGVH fiber mats is expected to be suitable for materials used in GBR, leading to control of infiltration of the soft tissue and great tissue integration with the surrounding tissue.

  9. Functional fiber mats with tunable diffuse reflectance composed of electrospun VO2/PVP composite fibers.

    PubMed

    Li, Shaotang; Li, Yamei; Qian, Kun; Ji, Shidong; Luo, Hongjie; Gao, Yanfeng; Jin, Ping

    2014-01-01

    Thermochromic VO2 nanoparticles have been dispersed into polyvinyl pyrrolidone (PVP) fibers by electrospinning of a VO2-PVP blend solution. The structure and optical properties of the obtained composite fiber mat were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet-visible (UV-Vis) spectrophotometry, and Fourier transform infrared (FT-IR) spectroscopy. The fiber mat revealed two diffuse reflectance states in infrared spectral region at temperatures under and above the phase transition temperature of VO2 and its IR reflectance is smaller in high temperature. The difference of diffuse reflectance between the two states (ΔRdif) was obvious to be more than 25% in the wavelengths from 1.5 μm to 6 μm. The diffuse reflectance of the fiber mat could be controlled by adjusting the diameter of the fiber or the content of VO2 in the fibers and this particular optical property was explained by a multiple scattering-absorbing process.

  10. Tough Stretchable Physically-Crosslinked Hydrogel Fiber Mats from Electrospun Statistical Copolymers

    NASA Astrophysics Data System (ADS)

    Yang, Yiming; Weiss, R. A.; Vogt, Bryan

    Nature uses supramolecular interactions combined with hierarchical structures to produce water-laden materials with combination of properties that are challenging to obtain in synthetic systems. Here we describe a simple method based on electrospinning of a self-associating amphiphilic copolymer. Immersion of the copolymer mats in water generates supramolecular hydrogels that are crosslinked by association of the fluorinated hydrophobic moieties in the copolymer. These robust hydrogel fiber mats exhibit extensibility greater than 225 % and the elastic modulus can be comparable to the bulk hydrogel despite the porous structure of the as-spun mat. Moreover, the stress dissipation by re-arrangement of the physically associated network leads to coalescence of the fibers that propagates from the surfaces to the interior of the mat. Both the mechanical properties and this fiber coalescence behavior can be tuned by selection of the copolymer composition and the initial fiber dimensions. These tough, stretchable hydrogel fiber mats could find utility in a variety of biomedical applications due to their unique properties.

  11. Novel PGS/PCL electrospun fiber mats with patterned topographical features for cardiac patch applications.

    PubMed

    Tallawi, M; Dippold, D; Rai, R; D'Atri, D; Roether, J A; Schubert, D W; Rosellini, E; Engel, F B; Boccaccini, A R

    2016-12-01

    Nano- and micro-scale topographical features play a critical role in the induction and maintenance of various cellular properties and functions, including morphology, adhesion, gene regulation, and cell-to-cell communication. In addition, recent studies have indicated that the structure and function of heart tissue are also sensitive to mechanical cues at the nano- and micro-scale. Although fabrication methods exist for generating topographical features on polymeric scaffolds for cell culture, current techniques, especially those with nano-scale resolution, are typically complex, prohibitively expensive and not accessible to most biology laboratories. Here, we present a simple and tunable fabrication method for the production of patterned electrospun fibers that simulate the complex anisotropic and multi-scale architecture of cardiac tissue, to promote cardiac cell alignment. This method is based on the combination of electrospinning and soft lithography techniques, in which electrospun fibers, based on a blend of poly(glycerol sebacate) and poly(caprolactone), were collected on a patterned Teflon-coated silicon wafer with imprinted topographical features. Different surface topographies were investigated, such as squares and grooves, with constant or different interspatial distances. In vitro cell culture studies successfully demonstrated the alignment of both C2C12 myoblasts and neonatal rat cardiomyocytes on fabricated electrospun patterned surfaces. C2C12 cells were cultured over a period of 72h to study the effect of topographical cues on cell morphology. Cells attached within the first 8h after seeding and after 24h most of the cells started to align responding to the topographical cues. Similarly, cardiomyocytes responded to the topographical features by aligning themselves and by expressing Connexin 43 along cellular junctions. Summarizing, we have developed a new method with the potential to significantly promote cardiac tissue engineering by fabricating

  12. Osteogenesis of human adipose-derived stem cells on poly(dopamine)-coated electrospun poly(lactic acid) fiber mats.

    PubMed

    Lin, Chi-Chang; Fu, Shu-Juan

    2016-01-01

    Electrospinning is a versatile technique to generate large quantities of micro- or nano-fibers from a wide variety of shapes and sizes of polymer. The aim of this study is to develop functionalized electrospun nano-fibers and use a mussel-inspired surface coating to regulate adhesion, proliferation and differentiation of human adipose-derived stem cells (hADSCs). We prepared poly(lactic acid) (PLA) fibers coated with polydopamine (PDA). The morphology, chemical composition, and surface properties of PDA/PLA were characterized by SEM and XPS. PDA/PLA modulated hADSCs' responses in several ways. Firstly, adhesion and proliferation of hADSCs cultured on PDA/PLA were significantly enhanced relative to those on PLA. Increased focal adhesion kinase (FAK) and collagen I levels and enhanced cell attachment and cell cycle progression were observed upon an increase in PDA content. In addition, the ALP activity and osteocalcin of hADSCs cultured on PDA/PLA were significantly higher than seen in those cultured on a pure PLA mat. Moreover, hADSCs cultured on PDA/PLA showed up-regulation of the ang-1 and vWF proteins associated with angiogenesis differentiation. Our results demonstrate that the bio-inspired coating synthetic degradable PLA polymer can be used as a simple technique to render the surfaces of synthetic biodegradable fibers, thus enabling them to direct the specific responses of hADSCs.

  13. Antibacterial Properties of Tough and Strong Electrospun PMMA/PEO Fiber Mats Filled with Lanasol—A Naturally Occurring Brominated Substance

    PubMed Central

    Andersson, Richard L.; Martínez-Abad, Antonio; Lagaron, José M.; Gedde, Ulf W.; Mallon, Peter E.; Olsson, Richard T.; Hedenqvist, Mikael S.

    2014-01-01

    A new type of antimicrobial, biocompatible and toughness enhanced ultra-thin fiber mats for biomedical applications is presented. The tough and porous fiber mats were obtained by electrospinning solution-blended poly (methyl methacrylate) (PMMA) and polyethylene oxide (PEO), filled with up to 25 wt % of Lanasol—a naturally occurring brominated cyclic compound that can be extracted from red sea algae. Antibacterial effectiveness was tested following the industrial Standard JIS L 1902 and under agitated medium (ASTM E2149). Even at the lowest concentrations of Lanasol, 4 wt %, a significant bactericidal effect was seen with a 4-log (99.99%) reduction in bacterial viability against S. aureus, which is one of the leading causes of hospital-acquired (nosocomial) infections in the world. The mechanical fiber toughness was insignificantly altered up to the maximum Lanasol concentration tested, and was for all fiber mats orders of magnitudes higher than electrospun fibers based on solely PMMA. This antimicrobial fiber system, relying on a dissolved antimicrobial agent (demonstrated by X-ray diffraction and Infrared (IR)-spectroscopy) rather than a dispersed and “mixed-in” solid antibacterial particle phase, presents a new concept which opens the door to tougher, stronger and more ductile antimicrobial fibers. PMID:25207601

  14. Electrospun gelatin fiber mats containing a herbal—Centella asiatica—extract and release characteristic of asiaticoside

    NASA Astrophysics Data System (ADS)

    Sikareepaisan, Panprung; Suksamrarn, Apichart; Supaphol, Pitt

    2008-01-01

    Ultra-fine gelatin (type A, porcine skin, ~180 Bloom) fiber mats containing a methanolic crude extract of Centella asiatica (L.) Urban, a medicinal plant widely known for its traditional medical applications including its wound healing ability, were fabricated, for the first time, from the neat gelatin solution (22% w/v in 70 vol% acetic acid) containing the crude extract (mCA) in various amounts (i.e. 5-30 wt% based on the weight of gelatin powder) by electrospinning. Incorporation of mCA in the neat gelatin solution did not affect both the morphology and the size of the mCA-loaded gelatin fibers, as both of the neat and the mCA-loaded gelatin fibers were smooth and the average diameters of these fibers ranged between 226 and 232 nm. The cross-linked mCA-loaded e-spun gelatin fiber mat from the neat gelatin solution containing 30 wt% of mCA was further investigated for the release characteristic of asiaticoside, identified as the most active compound associated with the healing of wounds, in two different types of releasing medium, i.e. acetate buffer and the buffer containing 10 vol% of methanol, based on the thin-layer chromatography (TLC)-densitometry technique. Based on the unit weight of the actual amount of asiaticoside present in the specimens, the total amount of asiaticoside released from the fiber mat specimens was lower than that from the film counterparts while, based on the unit weight of the specimens, an opposite trend was observed.

  15. Electrically conductive polyaniline-coated electrospun poly(vinylidene fluoride) mats

    NASA Astrophysics Data System (ADS)

    Merlini, Claudia; Barra, Guilherme; Ramoa, Sílvia; Contri, Giseli; Almeida, Rosemeire; D´Ávila, Marcos; Soares, Bluma

    2015-02-01

    Electrically conductive polyaniline (PANI)-coated electrospun poly(vinylidene fluoride) (PVDF) mats were fabricated through aniline (ANI) oxidative polymerization on electrospun PVDF mats. The effect of polymerization condition on structure and property of PVDF/PANI mats was investigated. The electrical conductivity and PANI content enhanced significantly with increasing ANI concentration due to the formation of a conducting polymer layer that completely coated the PVDF fibers surface. The PANI deposition on the PVDF fibers surface increased the Young Modulus and the elongation at break reduced significantly. Attenuated Total Reflectance-Fourier Transform Infrared spectroscopy (ATR-FTIR) revealed that the electrospun PVDF and PVDF/PANI mats display a polymorph crystalline structure, with absorption bands associated to the β, α and γ phases.

  16. Electrospun amplified fiber optics.

    PubMed

    Morello, Giovanni; Camposeo, Andrea; Moffa, Maria; Pisignano, Dario

    2015-03-11

    All-optical signal processing is the focus of much research aiming to obtain effective alternatives to existing data transmission platforms. Amplification of light in fiber optics, such as in Erbium-doped fiber amplifiers, is especially important for efficient signal transmission. However, the complex fabrication methods involving high-temperature processes performed in a highly pure environment slow the fabrication process and make amplified components expensive with respect to an ideal, high-throughput, room temperature production. Here, we report on near-infrared polymer fiber amplifiers working over a band of ∼20 nm. The fibers are cheap, spun with a process entirely carried out at room temperature, and shown to have amplified spontaneous emission with good gain coefficients and low levels of optical losses (a few cm(-1)). The amplification process is favored by high fiber quality and low self-absorption. The found performance metrics appear to be suitable for short-distance operations, and the large variety of commercially available doping dyes might allow for effective multiwavelength operations by electrospun amplified fiber optics.

  17. Electrospun Amplified Fiber Optics

    PubMed Central

    2015-01-01

    All-optical signal processing is the focus of much research aiming to obtain effective alternatives to existing data transmission platforms. Amplification of light in fiber optics, such as in Erbium-doped fiber amplifiers, is especially important for efficient signal transmission. However, the complex fabrication methods involving high-temperature processes performed in a highly pure environment slow the fabrication process and make amplified components expensive with respect to an ideal, high-throughput, room temperature production. Here, we report on near-infrared polymer fiber amplifiers working over a band of ∼20 nm. The fibers are cheap, spun with a process entirely carried out at room temperature, and shown to have amplified spontaneous emission with good gain coefficients and low levels of optical losses (a few cm–1). The amplification process is favored by high fiber quality and low self-absorption. The found performance metrics appear to be suitable for short-distance operations, and the large variety of commercially available doping dyes might allow for effective multiwavelength operations by electrospun amplified fiber optics. PMID:25710188

  18. Electrospun nanofibrous mats: from vascular repair to osteointegration.

    PubMed

    Ribba, L; Parisi, M; D'Accorso, N B; Goyanes, S

    2014-12-01

    Electrospinning is a versatile technique for generating a mat of continuous fibers with diameters from a few nanometers to several micrometers. The diversity of electrospinnable materials, and the unique features associated with electrospun fibers make this technique and its resultant structures attractive for applications in the biomedical field. This article presents an overview of this technique focusing on its application for tissue engineering. In particular, the advantages and disadvantages of using an electrospinning mat for biomedical applications are discussed. It reviews the different available electrospinning configurations, detailing how the different process variables and material types determine the obtained fibers characteristics. Then a description of how nanofiber based scaffolds offer great promise in the regeneration or function restoration of damaged or diseased bones, muscles or nervous tissue is reported. Different methods for incorporating active agents on nanofibers and controlling their release mechanisms are also reviewed. The review concludes with some personal perspectives on the future work to be done in order to include electrospinning technique in the industrial development of biomedical materials.

  19. Electrospun chitosan-based nanofiber mats loaded with Garcinia mangostana extracts.

    PubMed

    Charernsriwilaiwat, Natthan; Rojanarata, Theerasak; Ngawhirunpat, Tanasait; Sukma, Monrudee; Opanasopit, Praneet

    2013-08-16

    The aim of this study was to prepare electrospun chitosan-based nanofiber mats and to incorporate the fruit hull of Garcinia mangostana (GM) extracts into the mats. Chitosan-ethylenediaminetetraacetic acid/polyvinyl alcohol (CS-EDTA/PVA) was selected as the polymers. The GM extracts with 1, 2 and 3 wt% α-mangostin were incorporated into the CS-EDTA/PVA solution and electrospun to obtain nanofibers. The morphology and diameters of the mats were analyzed using scanning electron microscopy (SEM). The mechanical and swelling properties were investigated. The amount of GM extracts was determined using high-performance liquid chromatography (HPLC). The antioxidative activity, antibacterial activity, extract release and stability of the mats were evaluated. In vivo wound healing tests were also performed in Wistar rats. The results indicated that the diameters of the fibers were on the nanoscale and that no crystals of the extract were observed in the mats at any concentration. The mats provided suitable tensile strength and swelling properties. All of the mats exhibited antioxidant and antibacterial activity. During the wound healing test, the mats accelerated the rate of healing when compared to the control (gauze-covered). The mats maintained 90% of their content of α-mangostin for 3 months. In conclusion, the chitosan-based nanofiber mats loaded with GM extracts were successfully prepared using the electrospinning method. These nanofiber mats loaded with GM extracts may provide a good alternative for accelerating wound healing.

  20. Electrospun chitosan-based nanofiber mats loaded with Garcinia mangostana extracts.

    PubMed

    Charernsriwilaiwat, Natthan; Rojanarata, Theerasak; Ngawhirunpat, Tanasait; Sukma, Monrudee; Opanasopit, Praneet

    2013-08-16

    The aim of this study was to prepare electrospun chitosan-based nanofiber mats and to incorporate the fruit hull of Garcinia mangostana (GM) extracts into the mats. Chitosan-ethylenediaminetetraacetic acid/polyvinyl alcohol (CS-EDTA/PVA) was selected as the polymers. The GM extracts with 1, 2 and 3 wt% α-mangostin were incorporated into the CS-EDTA/PVA solution and electrospun to obtain nanofibers. The morphology and diameters of the mats were analyzed using scanning electron microscopy (SEM). The mechanical and swelling properties were investigated. The amount of GM extracts was determined using high-performance liquid chromatography (HPLC). The antioxidative activity, antibacterial activity, extract release and stability of the mats were evaluated. In vivo wound healing tests were also performed in Wistar rats. The results indicated that the diameters of the fibers were on the nanoscale and that no crystals of the extract were observed in the mats at any concentration. The mats provided suitable tensile strength and swelling properties. All of the mats exhibited antioxidant and antibacterial activity. During the wound healing test, the mats accelerated the rate of healing when compared to the control (gauze-covered). The mats maintained 90% of their content of α-mangostin for 3 months. In conclusion, the chitosan-based nanofiber mats loaded with GM extracts were successfully prepared using the electrospinning method. These nanofiber mats loaded with GM extracts may provide a good alternative for accelerating wound healing. PMID:23680732

  1. Fabrication of Gelatin/PCL Electrospun Fiber Mat with Bone Powder and the Study of Its Biocompatibility

    PubMed Central

    Rong, Dongming; Chen, Ping; Yang, Yuchao; Li, Qingtao; Wan, Wenbing; Fang, Xingxing; Zhang, Jie; Han, Zhongyu; Tian, Jing; Ouyang, Jun

    2016-01-01

    Fabricating ideal scaffolds for bone tissue engineering is a great challenge to researchers. To better mimic the mineral component and the microstructure of natural bone, several kinds of materials were adopted in our study, namely gelatin, polycaprolactone (PCL), nanohydroxyapatite (nHA), and bone powder. Three types of scaffolds were fabricated using electrospinning; gelatin/PCL, gelatin/PCL/nHA, and gelatin/PCL/bone powder. Scaffolds were examined using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations. Then, Adipose-derived Stem Cells (ADSCs) were seeded on these scaffolds to study cell morphology, cell viability, and proliferation. Through this study, we found that nHA and bone powder can be successfully united in gelatin/PCL fibers. When compared with gelatin/PCL and gelatin/PCL/nHA, the gelatin/PCL/bone powder scaffolds could provide a better environment to increase ADSCs’ growth, adhesion, and proliferation. Thus, we think that gelatin/PCL/bone powder has good biocompatibility, and, when compared with nHA, bone powder may be more effective in bone tissue engineering due to the bioactive factors contained in it. PMID:26959071

  2. Robust fabrication of electrospun-like polymer mats to direct cell behaviour.

    PubMed

    Ballester-Beltrán, José; Lebourg, Myriam; Capella, Hector; Diaz Lantada, Andres; Salmerón-Sánchez, Manuel

    2014-09-01

    Currently, cell culture systems that include nanoscale topography are widely used in order to provide cells additional cues closer to the in vivo environment, seeking to mimic the natural extracellular matrix. Electrospinning is one of the most common techniques to produce nanofiber mats. However, since many sensitive parameters play an important role in the process, a lack of reproducibility is a major drawback. Here we present a simple and robust methodology to prepare reproducible electrospun-like samples. It consists of a polydimethylsiloxane mold reproducing the fiber pattern to solvent-cast a polymer solution and obtain the final sample. To validate this methodology, poly(L-lactic) acid (PLLA) samples were obtained and, after characterisation, bioactivity and ability to direct cell response were assessed. C2C12 myoblasts developed focal adhesions on the electrospun-like fibers and, when cultured under myogenic differentiation conditions, similar differentiation levels to electrospun PLLA fibers were obtained.

  3. Direct Piezoelectricity of Soft Composite Electrospun Fibers

    NASA Astrophysics Data System (ADS)

    Varga, Michael; Morvan, Jason; Diorio, Nick; Buyuktanir, Ebru; Harden, John; West, John; Jakli, Antal

    2013-03-01

    Recently soft fiber mats electrospun from solutions of Barium Titanate (BT) ferroelectric ceramics particles and poly lactic acid (PLA) were found to have large (d33 1nm/V) converse piezoelectric signals offering a myriad of applications ranging from active implants to smart textiles. Here we report direct piezoelectric measurements (electric signals due to mechanical stress) of the BT/PLA composite fiber mats at various BT concentrations. A testing apparatus was designed and constructed solely for these measurements involving AC stresses provided by a speaker in 10Hz-10kHz frequency range. The piezoelectric constant d33 ~1nC/N was found to be in agreement with the prior converse piezoelectric measurements. The largest signals were obtained with 6% BT/PLA composites, probably because the BT particles at higher concentrations could not be dispersed homogeneously. Importantly the direct piezoelectric signal is large enough to power a small LCD by simply pressing a 0.2mm thick 2 cm2 area mat by a finger. We expect to use these mats in active Braille cells and in liquid crystal writing tablets.

  4. Structural, electrical, mechanical, and thermal properties of electrospun poly(lactic acid)/polyaniline blend fibers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conducting electrospun fiber mats based on PLA and PAni blends were obtained with average diameter values between 87 and 1,006 nm with PAni quantities from 0 to 5.6 wt.-%. Structural characteristics of fiber mats were compared to cast films with the same amount of PAni and studied by SEM, SAXS, and ...

  5. Various-sourced pectin and polyethylene oxide electrospun fibers.

    PubMed

    Rockwell, Pamela L; Kiechel, Marjorie A; Atchison, Jennifer S; Toth, Laura J; Schauer, Caroline L

    2014-07-17

    Pectin, a naturally occurring and biorenewable polysaccharide, is derived from plant cell wall tissue and used in applications ranging from food processing to biomedical engineering. Due to extraction methods and source variation, there is currently no consensus in literature as to the exact structure of pectin. Here, we have studied key material properties of electrospun pectin blends with polyethylene oxide (PEO) (1:1, v/v) in order to demonstrate the fabrication of a fibrous and less toxic material system, as well as to understand the effects of source variability on the resulting fibrous mats. The bulk pectin degree of esterification (DE) estimated using FTIR (bulk apple pomace (AP)=28%, bulk citrus peel (CP)=86% and bulk sugar beet pulp (SBP)=91%) was shown to inversely correlate with electrospun fiber crystallinity determined using XRD (PEO-AP=37%, PEO-CP=28% and PEO-SBP=23%). This in turn affected the trend observed for the mean fiber diameter (n=50) (PEO-AP=124 ± 26 nm, PEO-CP=493 ± 254 nm and PEO-SBP=581 ± 178 nm) and elastic tensile moduli (1.6 ± 0.2 MPa, 4.37 ± 0.64 MPa and 2.49 ± 1.46 MPa, respectively) of the fibrous mats. Electrospun fibers containing bulk AP had the lowest DE, highest crystallinity, smallest mean fiber diameter, and lowest tensile modulus compared to either the bulk CP or bulk SBP. Bound water in PEO-CP fiber and bulk pectin impurities in PEO-SPB were observed to influence fiber branching and mean diameter distributions, which in turn influenced the fiber tensile properties. These results indicate that pectin, when blended with PEO in water, produces submicron fibrous mats with pectin influencing the blend fiber properties. Moreover, the source of pectin is an important variable in creating electrospun blend fibrous mats with desired material properties.

  6. Three-dimensional electrospun alginate nanofiber mats via tailored charge repulsions.

    PubMed

    Bonino, Christopher A; Efimenko, Kirill; Jeong, Sung In; Krebs, Melissa D; Alsberg, Eben; Khan, Saad A

    2012-06-25

    The formation of 3D electrospun mat structures from alginate-polyethylene oxide (PEO) solution blends is reported. These unique architectures expand the capabilities of traditional electrospun mats for applications such as regenerative medicine, where a scaffold can help to promote tissue growth in three dimensions. The mat structures extend off the surface of the flat collector plate without the need of any modifications in the electrospinning apparatus, are self-supported when the electric field is removed, and are composed of bundles of nanofibers. A mechanism for the unique formations is proposed, based on the fiber-fiber repulsions from surface charges on the negatively charged alginate. Furthermore, the role of the electric field in the distribution of alginate within the nanofibers is discussed. X-ray photoelectron spectroscopy is used to analyze the surface composition of the electrospun nanofiber mats and the data is related to cast films made in the absence of the electric field. Further techniques to tailor the 3D architecture and nanofiber morphology by changing the surface tension and relative humidity are also discussed.

  7. Electrospun Fibers for Energy, Electronic, & Environmental Applications

    NASA Astrophysics Data System (ADS)

    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

  8. Aligned Electrospun Polyvinyl Pyrrolidone/Poly ɛ-Caprolactone Blend Nanofiber Mats for Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Charernsriwilaiwat, Natthan; Rojanarata, Theerasak; Ngawhirunpat, Tanasait; Opanasopit, Praneet

    2016-02-01

    Electrospun nanofibrous materials are widely used in medical applications such as tissue engineering scaffolds, wound dressing material and drug delivery carriers. For tissue engineering scaffolds, the structure of the nanofiber is similar to extracellular matrix (ECM) which promotes the cell growth and proliferation. In the present study, the aligned nanofiber mats of polyvinyl pyrrolidone (PVP) blended poly ɛ-caprolactone (PCL) was successfully generated using electrospinning technique. The morphology of PVP/PCL nanofiber mats were characterized by scanning electron microspore (SEM). The chemical and crystalline structure of PVP/PCL nanofiber mats were analyzed using Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffactometer (PXRD). The water contact angle of mats was investigated. Cell culture studies using normal human fibroblasts (NHF) were performed to assess cell morphology, cell alignment and cell proliferation. The results indicated that the fiber were in nanometer range. The PVP/PCL was well dispersed in nanofiber mats and was in amorphous form. The water contact angle of PVP/PCL nanofiber mats was lower than PCL nanofiber mats. The PVP/PCL nanofiber mats exhibited good biocompatibility with NHF cells. In summary, the PVP/PCL nanofiber mats had potential to be used in tissue engineering and regenerative medicine.

  9. Nanomechanics of electrospun phospholipid fiber

    SciTech Connect

    Mendes, Ana C. E-mail: ioach@food.dtu.dk; Chronakis, Ioannis S. E-mail: ioach@food.dtu.dk; Nikogeorgos, Nikolaos; Lee, Seunghwan

    2015-06-01

    Electrospun asolectin phospholipid fibers were prepared using isooctane as a solvent and had an average diameter of 6.1 ± 2.7 μm. Their mechanical properties were evaluated by nanoindentation using Atomic Force Microscopy, and their elastic modulus was found to be approximately 17.2 ± 1 MPa. At a cycle of piezo expansion-retraction (loading-unloading) of a silicon tip on a fiber, relatively high adhesion was observed during unloading. It is proposed that this was primarily due to molecular rearrangements at the utmost layers of the fiber caused by the indentation of the hydrophilic tip. The phospholipid fibers were shown to be stable in ambient conditions, preserving the modulus of elasticity up to 24 h.

  10. Hysteresis Phenomenon in Heat-Voltage Curves of Polypyrrole-Coated Electrospun Nanofibrous and Regular Fibrous Mats

    NASA Astrophysics Data System (ADS)

    Oroumei, Azam; Tavanai, Hossein; Morshed, Mohammad

    2015-07-01

    This article verifies the hysteresis phenomenon in heat-voltage curves of polypyrrole-coated electrospun nanofibrous and regular fibrous mats. A third-order polynomial model fits the heat-voltage data better than a second-order polynomial model. It was also observed that the hysteresis loop area of nanofibrous and regular fibrous mats increases with decreasing fiber diameter. Moreover, the curvature of the hysteresis loops is significantly affected by the fiber diameter. In fact, the slope of the curvatures increases with decreasing fiber diameter.

  11. Antibacterial electrospun chitosan-polyethylene oxide nanocomposite mats containing ZIF-8 nanoparticles.

    PubMed

    Kohsari, Iraj; Shariatinia, Zahra; Pourmortazavi, Seied Mahdi

    2016-10-01

    Antimicrobial chitosan-polyethylene oxide (CS-PEO) nanofiber mats loaded with 3, 5 and 10% (w/w) of zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs, ∼60nm diameter) were developed by electrospinning technique. The CS-PEO-GA-3% ZIF-8 NPs crosslinked with glutaraldehyde (GA) vapor was also prepared. The electrospun mats were characterized by various analysis including FE-SEM, EDAX, elemental mapping, FT-IR, contact angle, TGA/DSC as well as tensile strength analysis. The nanofibers had average diameters within the range ∼70-120nm. Antimicrobial activities of the CS-PEO and CS-PEO-3% ZIF-8 mats were evaluated by the viable cell-counting method for determining their effectiveness in reducing or halting the growth of Staphylococcus aureus and Escherichia coli bacteria so that the CS-PEO mat containing 3% ZIF-8 revealed 100% bactericidal activity against both kinds of bacteria. The crosslinked CS-PEO-GA-3% ZIF-8 NPs sample was less thermally stable but more hydrophilic than its related non-crosslinked mat reflecting there was no need to crosslink the fibers using a chemical crosslinker having adverse effects. The highest hydrophobicity and appropriate thermal and tensile properties of CS-PEO-3% ZIF-8 NPs among those of the mats including 5 and 10% ZIF-8 NPs suggested that the mentioned mat is the most suitable sample for food coating applications. PMID:27311504

  12. Structural, electrical, mechanical and thermal properties of electrospun fibers of poly(lactic acid)/polyaniline blend.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conducting electrospun fiber mats based on PLA and PAni blends were obtained with average diameter values between 87 and 1 006nm with PAni quantities from 0 to 5.6 wt.-%. Structural characteristics of fiber mats were compared to cast films with the same amount of PAni and studied by SEM, SAXS, and A...

  13. Facile control of intra-fiber porosity and inter-fiber voids in electrospun fibers for selective adsorption

    NASA Astrophysics Data System (ADS)

    Lin, Jinyou; Tian, Feng; Shang, Yanwei; Wang, Fujun; Ding, Bin; Yu, Jianyong

    2012-08-01

    We report a facile method to control intra-fiber porosity via varying the relative humidity and inter-fiber voids through the blending of two different polymeric fibers via multi-nozzles spinning of electrospun fibers for selective adsorption of oil from water.We report a facile method to control intra-fiber porosity via varying the relative humidity and inter-fiber voids through the blending of two different polymeric fibers via multi-nozzles spinning of electrospun fibers for selective adsorption of oil from water. Electronic supplementary information (ESI) available: FE-SEM images, nitrogen physisorption isotherms, differential pore volume vs. pore width, SAXS 2D scattering patterns and SAXS curves of PS (Mw = 208 000 g mol-1) fibrous mats formed at different RH (Fig. S1). Iron element distribution of a single fiber (Fig. S2). A schematic diagram to show the multi-nozzles electrospinning (Fig. S3). FE-SEM images of as-prepared fibrous mats formed with various PS/PU nozzle ratios (Fig. S4). Nitrogen physisorption isotherms, SSA, and water contact angles of as-prepared fibrous mats formed with various PS/PU nozzle ratios (Fig. S5 and S6). Hydrophobicity-oleophilicity of an as-spun fibrous mat (Fig. S7). Typical tensile stress-strain curves of various PS fibrous mats with the addition of PU fibers formed from a 50 wt% PU resin (Fig. S8). Surface characterization of as-prepared fibers (Table S1). Tensile properties of the fibrous mats (Tables S2 and S3). See DOI: 10.1039/c2nr31515g

  14. Development of electrospun beaded fibers from Thai silk fibroin and gelatin for controlled release application.

    PubMed

    Somvipart, Siraporn; Kanokpanont, Sorada; Rangkupan, Rattapol; Ratanavaraporn, Juthamas; Damrongsakkul, Siriporn

    2013-04-01

    Thai silk fibroin and gelatin are attractive biomaterials for tissue engineering and controlled release applications due to their biocompatibility, biodegradability, and bioactive properties. The development of electrospun fiber mats from silk fibroin and gelatin were reported previously. However, burst drug release from such fiber mats remained the problem. In this study, the formation of beads on the fibers aiming to be used for the sustained release of drug was of our interest. The beaded fiber mats were fabricated using electrospinning technique by controlling the solution concentration, weight blending ratio of Thai silk fibroin/gelatin blend, and applied voltage. It was found that the optimal conditions including the solution concentration and the weight blending ratio of Thai silk fibroin/gelatin at 8-10% (w/v) and 70/30, respectively, with the applied voltage at 18 kV provided the fibers with homogeneous formation of beads. Then, the beaded fiber mats obtained were crosslinked by the reaction of carbodiimide hydrochloride (EDC)/N-hydroxysuccinimide (NHS). Methylene blue as a model active compound was loaded on the fiber mats. The release test of methylene blue from the beaded fiber mats was carried out in comparison to that of the smooth fiber mats without beads. It was found that the beaded fiber mats could prolong the release of methylene blue, comparing to the smooth fiber mats without beads. This was possibly due to the beaded fiber mats that would absorb and retain higher amount of methylene blue than the fiber mats without beads. Thai silk fibroin/gelatin beaded fiber mats were established as an effective carrier for the controlled release applications.

  15. Biofunctionalized electrospun silk mats as a topical bioactive dressing for accelerated wound healing.

    PubMed

    Schneider, A; Wang, X Y; Kaplan, D L; Garlick, J A; Egles, C

    2009-09-01

    Materials able to deliver topically bioactive molecules represent a new generation of biomaterials. In this article, we describe the use of silk mats, made of electrospun nanoscale silk fibers containing epidermal growth factor (EGF), for the promotion of wound healing processes. In our experiments, we demonstrated that EGF is incorporated into the silk mats and slowly released in a time-dependent manner (25% EGF release in 170h). We tested these materials using a new model of wounded human skin-equivalents displaying the same structure as human skin and able to heal using the same molecular and cellular mechanisms found in vivo. This human three-dimensional model allows us to demonstrate that the biofunctionalized silk mats, when placed on the wounds as a dressing, aid the healing by increasing the time of wound closure by the epidermal tongue by 90%. The preservation of the structure of the mats during the healing period as demonstrated by electronic microscopy, the biological action of the dressing, as well as the biocompatibility of the silk demonstrate that this biomaterial is a new and very promising material for medical applications, especially for patients suffering from chronic wounds.

  16. Electrospun nanofiber scaffolds with gradations in fiber organization.

    PubMed

    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.

  17. Electrospun nanofiber scaffolds with gradations in fiber organization.

    PubMed

    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

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

    PubMed

    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.

  19. Direct piezoelectric responses of soft composite fiber mats

    NASA Astrophysics Data System (ADS)

    Varga, M.; Morvan, J.; Diorio, N.; Buyuktanir, E.; Harden, J.; West, J. L.; Jákli, A.

    2013-04-01

    Recently soft fiber mats electrospun from solutions of Barium Titanate (BT) ferroelectric ceramics particles and polylactic acid (PLA) were found to have large (d33 ˜ 1 nm/V) converse piezoelectric signals offering a myriad of applications ranging from active implants to smart textiles. Here, we report direct piezoelectric measurements (electric signals due to mechanical stress) of the BT/PLA composite fiber mats at several BT concentrations. A homemade testing apparatus provided AC stresses in the 50 Hz-1.5 kHz-frequency range. The piezoelectric constant d33 ˜ 0.5 nC/N and the compression modulus Y ˜ 104-105 Pa found are in agreement with the prior converse piezoelectric and compressibility measurements. Importantly, the direct piezoelectric signal is large enough to power a small LCD by simple finger tapping of a 0.15 mm thick 2-cm2 area mat. We propose using these mats in active Braille cells and in liquid crystal writing tablets.

  20. Nonwoven glass fiber mat reinforces polyurethane adhesive

    NASA Technical Reports Server (NTRS)

    Roseland, L. M.

    1967-01-01

    Nonwoven glass fiber mat reinforces the adhesive properties of a polyurethane adhesive that fastens hardware to exterior surfaces of aluminum tanks. The mat is embedded in the uncured adhesive. It ensures good control of the bond line and increases the peel strength.

  1. Electrospun Nanofiber Mats as "Smart Surfaces" for Desorption Electrospray Ionization Mass Spectrometry (DESI MS)-Based Analysis and Imprint Imaging.

    PubMed

    Hemalatha, R G; Ganayee, Mohd Azhardin; Pradeep, T

    2016-06-01

    In this paper, desorption electrospray ionization mass spectrometry (DESI MS)-based molecular analysis and imprint imaging using electrospun nylon-6 nanofiber mats are demonstrated for various analytical contexts. Uniform mats of varying thicknesses composed of ∼200 nm diameter fibers were prepared using needleless electrospinning. Analytical applications requiring rapid understanding of the analytes in single drops, dyes, inks, and/or plant extracts incorporated directly into the nanofibers are discussed with illustrations. The possibility to imprint patterns made of printing inks, plant parts (such as petals, leaves, and slices of rhizomes), and fungal growth on fruits with their faithful reproductions on the nanofiber mats is illustrated with suitable examples. Metabolites were identified by tandem mass spectrometry data available in the literature and in databases. The results highlight the significance of electrospun nanofiber mats as smart surfaces to capture diverse classes of compounds for rapid detection or to imprint imaging under ambient conditions. Large surface area, appropriate chemical functionalities exposed, and easiness of desorption due to weaker interactions of the analyte species are the specific advantages of nanofibers for this application. PMID:27159150

  2. Characterization of electrospun lignin based carbon fibers

    NASA Astrophysics Data System (ADS)

    Poursorkhabi, Vida; Mohanty, Amar; Misra, Manjusri

    2015-05-01

    The production of lignin fibers has been studied in order to replace the need for petroleum based precursors for carbon fiber production. In addition to its positive environmental effects, it also benefits the economics of the industries which cannot take advantage of carbon fiber properties because of their high price. A large amount of lignin is annually produced as the byproduct of paper and growing cellulosic ethanol industry. Therefore, finding high value applications for this low cost, highly available material is getting more attention. Lignin is a biopolymer making about 15 - 30 % of the plant cell walls and has a high carbon yield upon carbonization. However, its processing is challenging due to its low molecular weight and also variations based on its origin and the method of separation from cellulose. In this study, alkali solutions of organosolv lignin with less than 1 wt/v% of poly (ethylene oxide) and two types of lignin (hardwood and softwood) were electrospun followed by carbonization. Different heating programs for carbonization were tested. The carbonized fibers had a smooth surface with an average diameter of less than 5 µm and the diameter could be controlled by the carbonization process and lignin type. Scanning electron microscopy (SEM) was used to study morphology of the fibers before and after carbonization. Thermal conductivity of a sample with amorphous carbon was 2.31 W/m.K. The electrospun lignin carbon fibers potentially have a large range of application such as in energy storage devices and water or gas purification systems.

  3. Mucoadhesive electrospun chitosan-based nanofibre mats for dental caries prevention.

    PubMed

    Samprasit, Wipada; Kaomongkolgit, Ruchadaporn; Sukma, Monrudee; Rojanarata, Theerasak; Ngawhirunpat, Tanasait; Opanasopit, Praneet

    2015-03-01

    The mucoadhesive electrospun nanofibre mats were developed using chitosan (CS) and thiolated chitosan (CS-SH) as mucoadhesive polymers. Garcinia mangostana (GM) extract was incorporated into nanofibre mats. The antibacterial activity in the single and combined agents was evaluated against dental caries pathogens. The morphology of mats was observed using SEM. The mats were evaluated for GM extract amount, mucoadhesion, in vitro release, antibacterial activity and cytotoxicity. The mucoadhesion and antibacterial activity were determined in healthy human volunteers. The prepared mats were in nanoscale with good physical and mucoadhesive properties. The CS-SH caused the higher mucoadhesion. All mats rapidly released active substances, which had the synergistic antibacterial activity. In addition, the reduction of bacteria and good mucoadhesion in the oral cavity occurred without cytotoxicity. The results suggest that mats have the potential to be mucoadhesive dosage forms to maintain oral hygiene by reducing the bacterial growth that causes the dental caries.

  4. Mechanical properties of single electrospun collagen type I fibers.

    PubMed

    Yang, Lanti; Fitié, Carel F C; van der Werf, Kees O; Bennink, Martin L; Dijkstra, Pieter J; Feijen, Jan

    2008-03-01

    The mechanical properties of single electrospun collagen fibers were investigated using scanning mode bending tests performed with an AFM. Electrospun collagen fibers with diameters ranging from 100 to 600 nm were successfully produced by electrospinning of an 8% w/v solution of acid soluble collagen in 1,1,1,3,3,3-hexafluoro-2-propanol (HFP). Circular dichroism (CD) spectroscopy showed that 45% of the triple helical structure of collagen molecules was denatured in the electrospun fibers. The electrospun fibers were water soluble and became insoluble after cross-linking with glutaraldehyde vapor for 24h. The bending moduli and shear moduli of both non- and cross-linked single electrospun collagen fibers were determined by scanning mode bending tests after depositing the fibers on glass substrates containing micro-channels. The bending moduli of the electrospun fibers ranged from 1.3 to 7.8 GPa at ambient conditions and ranged from 0.07 to 0.26 MPa when immersed in PBS buffer. As the diameter of the fibrils increased, a decrease in bending modulus was measured clearly indicating mechanical anisotropy of the fiber. Cross-linking of the electrospun fibers with glutaraldehyde vapor increased the shear modulus of the fiber from approximately 30 to approximately 50 MPa at ambient conditions. PMID:18082253

  5. Enhanced dechlorination of trichloroethylene using electrospun polymer nanofibrous mats immobilized with iron/palladium bimetallic nanoparticles.

    PubMed

    Ma, Hui; Huang, Yunpeng; Shen, Mingwu; Guo, Rui; Cao, Xueyan; Shi, Xiangyang

    2012-04-15

    Fe/Pd bimetallic nanoparticles (NPs) have held great promise for treating trichloroethylene (TCE)-contaminated groundwater, without the accumulation of chlorinated intermediates. However, the conventionally used colloidal Fe/Pd NPs usually aggregate rapidly, resulting in a reduced reactivity. To reduce the particle aggregation, we employed electrospun polyacrylic acid (PAA)/polyvinyl alcohol (PVA) polymer nanofibers as a nanoreactor to immobilize Fe/Pd bimetallic NPs. In the study, the water-stable PAA/PVA nanofibrous mats were complexed with Fe (III) ions via the binding with the free carboxyl groups of PAA for subsequent formation and immobilization of zero-valent iron (ZVI) NPs. Fe/Pd bimetallic NPs were then formed by the partial reduction of Pd(II) ions with ZVI NPs. The formed electrospun nanofibrous mats containing Fe/Pd bimetallic NPs with a diameter of 2.8 nm were characterized by scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, thermogravimetric analysis, and inductively coupled plasma-atomic emission spectroscopy. The Fe/Pd NP-containing electrospun PAA/PVA nanofibrous mats exhibited higher reactivity than that of the ZVI NP-containing mats or colloidal Fe/Pd NPs in the dechlorination of trichloroethylene (TCE), which was used as a model contaminant. With the high surface area to volume ratio, high porosity, and great reusability of the fibrous mats immobilized with the bimetallic NPs, the composite nanofibrous mats should be amenable for applications in remediation of various environmental contaminants. PMID:22138171

  6. Enhanced dechlorination of trichloroethylene using electrospun polymer nanofibrous mats immobilized with iron/palladium bimetallic nanoparticles.

    PubMed

    Ma, Hui; Huang, Yunpeng; Shen, Mingwu; Guo, Rui; Cao, Xueyan; Shi, Xiangyang

    2012-04-15

    Fe/Pd bimetallic nanoparticles (NPs) have held great promise for treating trichloroethylene (TCE)-contaminated groundwater, without the accumulation of chlorinated intermediates. However, the conventionally used colloidal Fe/Pd NPs usually aggregate rapidly, resulting in a reduced reactivity. To reduce the particle aggregation, we employed electrospun polyacrylic acid (PAA)/polyvinyl alcohol (PVA) polymer nanofibers as a nanoreactor to immobilize Fe/Pd bimetallic NPs. In the study, the water-stable PAA/PVA nanofibrous mats were complexed with Fe (III) ions via the binding with the free carboxyl groups of PAA for subsequent formation and immobilization of zero-valent iron (ZVI) NPs. Fe/Pd bimetallic NPs were then formed by the partial reduction of Pd(II) ions with ZVI NPs. The formed electrospun nanofibrous mats containing Fe/Pd bimetallic NPs with a diameter of 2.8 nm were characterized by scanning electron microscopy, energy-dispersive spectroscopy, transmission electron microscopy, thermogravimetric analysis, and inductively coupled plasma-atomic emission spectroscopy. The Fe/Pd NP-containing electrospun PAA/PVA nanofibrous mats exhibited higher reactivity than that of the ZVI NP-containing mats or colloidal Fe/Pd NPs in the dechlorination of trichloroethylene (TCE), which was used as a model contaminant. With the high surface area to volume ratio, high porosity, and great reusability of the fibrous mats immobilized with the bimetallic NPs, the composite nanofibrous mats should be amenable for applications in remediation of various environmental contaminants.

  7. Electrospun polymer mat as a SERS platform for the immobilization and detection of bacteria from fluids.

    PubMed

    Szymborski, Tomasz; Witkowska, Evelin; Adamkiewicz, Witold; Waluk, Jacek; Kamińska, Agnieszka

    2014-10-21

    This work demonstrates the development of a new class of SERS substrates that allows for the simultaneous: (i) filtration of bacteria from any solution (blood, urine, water, or milk), (ii) immobilization of bacteria on the SERS platform, and (iii) enhancing the Raman signal of bacteria. The proposed platform is based on an electrospun polymer mat covered with a 90 nm layer of gold.

  8. Characterization of electrospun lignin based carbon fibers

    SciTech Connect

    Poursorkhabi, Vida; Mohanty, Amar; Misra, Manjusri

    2015-05-22

    The production of lignin fibers has been studied in order to replace the need for petroleum based precursors for carbon fiber production. In addition to its positive environmental effects, it also benefits the economics of the industries which cannot take advantage of carbon fiber properties because of their high price. A large amount of lignin is annually produced as the byproduct of paper and growing cellulosic ethanol industry. Therefore, finding high value applications for this low cost, highly available material is getting more attention. Lignin is a biopolymer making about 15 – 30 % of the plant cell walls and has a high carbon yield upon carbonization. However, its processing is challenging due to its low molecular weight and also variations based on its origin and the method of separation from cellulose. In this study, alkali solutions of organosolv lignin with less than 1 wt/v% of poly (ethylene oxide) and two types of lignin (hardwood and softwood) were electrospun followed by carbonization. Different heating programs for carbonization were tested. The carbonized fibers had a smooth surface with an average diameter of less than 5 µm and the diameter could be controlled by the carbonization process and lignin type. Scanning electron microscopy (SEM) was used to study morphology of the fibers before and after carbonization. Thermal conductivity of a sample with amorphous carbon was 2.31 W/m.K. The electrospun lignin carbon fibers potentially have a large range of application such as in energy storage devices and water or gas purification systems.

  9. Electrospun magnetic nanofibre mats - A new bondable biomaterial using remotely activated magnetic heating

    NASA Astrophysics Data System (ADS)

    Zhong, Yi; Leung, Victor; Yuqin Wan, Lynn; Dutz, Silvio; Ko, Frank K.; Häfeli, Urs O.

    2015-04-01

    A solvothermal process was adopted to produce hydrophilic magnetite (Fe3O4) nanoparticles which were subsequently emulsified with a chloroform/methanol (70/30 v/v) solution of poly(caprolactone) (PCL) and then electrospun into a 0.2 mm thick PCL mat. The magnetic heating of the mats at a field amplitude of 25 kA/m and frequency of 400 kHz exhibited promising efficiency for magnetic hyperthermia, with a specific absorption rate of about 40 W/g for the magnetic mat. The produced heat was used to melt the magnetic mat onto the surrounding non-magnetic polymer mat from within, without destroying the nanostructure of the non-magnetic polymer more than 0.5 mm away. Magnetic nanofibre mats might thus be useful for internal heat sealing applications, and potentially also for thermotherapy.

  10. Mechanisms of stability of electrospun polypeptide fibers

    NASA Astrophysics Data System (ADS)

    Gitnik, Alina; Khadka, Dhan; Cross, Michael; Le, Nicole; Haynie, Donald

    2013-03-01

    Electrospun nano- and microfibers made of biodegradable and absorbable polymers are of great interest in biomedical engineering for tissue engineering, wound healing and other purposes. We have investigated physical properties of fibers made of the synthetic organic polymer co-poly(L-glutamic acid4, L-tyrosine1) (PLEY). This water-soluble polypeptide has a net negative charge at neutral pH. Dehydrated fibers are crosslinked with a diimide reagent dissolved in ethanol, giving a maximum average number of crosslinks of 1 per polymer molecule. Fiber integrity has been assessed in an aqueous medium at pH 2, 7 and 12, before and after crosslinking. Non-crosslinked fibers dissolved rapidly at all pH values, on a timescale of seconds to minutes. Crosslinked fibers dissolved completely at pH 12, but not at pH 2 or pH 7, the rate depending on the concentration of crosslinking reagent and therefore the density of crosslinks. Dissolution at pH 12 is attributable to ionization of the tyrosine side chain, which has a nominal pKa of 10.4, an increase in electrostatic repulsion between side chains and the migration of counterions into the fiber. Fibers crosslinked in 50 mM EDC buckled on a timescale of minutes at pH 12 and dissolved shortly thereafter. Funding provided by the National Science Foundation

  11. Mussel inspired protein-mediated surface modification to electrospun fibers and their potential biomedical applications.

    PubMed

    Xie, Jingwei; Michael, Praveesuda Lorwattanapongsa; Zhong, Shaoping; Ma, Bing; MacEwan, Matthew R; Lim, Chwee Teck

    2012-04-01

    Mussel inspired proteins have been demonstrated to serve as a versatile biologic adhesive with numerous applications. The present study illustrates the use of such Mussel inspired proteins (polydopamine) in the fabrication of functionalized bio-inspired nanomaterials capable of both improving cell response and sustained delivery of model probes. X-ray photoelectron spectroscopy analysis confirmed the ability of dopamine to polymerize on the surface of plasma-treated, electrospun poly(ε-caprolactone) (PCL) fiber mats to form polydopamine coating. Transmission electron microscopy images demonstrated that self-polymerization of dopamine was induced by pH shift and that the thickness of polydopamine coating was readily modulated by adjusting the concentration of dopamine and reaction time. Polydopamine coatings were noted to affect the mechanical properties of underlying fiber mats, as mechanical testing demonstrated a decrease in elasticity and increase in stiffness of polydopamine-coated fiber mats. Polydopamine coatings were also utilized to effectively immobilize extracellular matrix proteins (i.e., fibronectin) on the surface of polydopamine-coated, electrospun fibers, resulting in enhancement of NIH3T3 cell attachment, spreading, and cytoskeletal development. Comparison of release rates of rhodamine 6G encapsulated in coated and uncoated PCL fibers also confirmed that polydopamine coatings modulate the release rate of loaded payloads. The authors further demonstrate the significant difference of rhodamine 6G adsorption kinetics in water between PCL fibers and polydopamine-coated PCL fibers. Taken together, polydopamine-mediated surface modification to electrospun fibers may be an effective means of fabricating a wide range of bio-inspired nanomaterials with unique properties for use in tissue engineering, drug delivery, and advanced biomedical applications.

  12. Biomimetic composite scaffolds based on mineralization of hydroxyapatite on electrospun poly(ɛ-caprolactone)/nanocellulose fibers.

    PubMed

    Si, Junhui; Cui, Zhixiang; Wang, Qianting; Liu, Qiong; Liu, Chuntai

    2016-06-01

    A biomimetic nanocomposite scaffold with HA formation on the electrospun poly(ɛ-caprolactone) (PCL)/nanocellulose (NC) fibrous matrix was developed in this study. The electrospun PCL/NC fiber mat was built and then biomineralized by treatment in simulated body fluid (SBF). Using such a rapid and effective procedure, a continuous biomimetic crystalline HA layer could be successfully formed without the need of any additional chemical modification of the substrate surface. The results showed that the introduction of NC into composite fibers is an effective approach to induce the deposition of HA nucleus as well as to improve their distribution and growth of a crystalline HA layer on the fibrous scaffolds. The water contact angle (WCA) of the PCL/NC/HA scaffolds decreases with increasing NC content and mineralization time, resulting in the enhancement of their hydrophilicity. These results indicated that HA-mineralized on PCL/NC fiber can be prepared directly by simply using SBF immersion. PMID:27083369

  13. Investigation of drug release and matrix degradation of electrospun poly(DL-lactide) fibers with paracetanol inoculation.

    PubMed

    Cui, Wenguo; Li, Xiaohong; Zhu, Xinli; Yu, Guo; Zhou, Shaobing; Weng, Jie

    2006-05-01

    This study was aimed at assessing the potential use of electrospun fibers as drug delivery vehicles with focus on the different diameters and drug contents to control drug release and polymer fiber degradation. A drug-loaded solvent-casting polymer film was made with an average thickness of 100 microm for comparative purposes. DSC analysis indicated that electrospun fibers had a lower T(g) but higher transition enthalpy than solvent-casting polymer film due to the inner stress and high degree of alignment and orientation of polymer chains caused by the electrospinning process. Inoculation of paracetanol led to a further slight decrease in the T(g) and transition enthalpy. An in vitro drug release study showed that a pronounced burst release or steady release phase was initially observed followed by a plateau or gradual release during the rest time. Fibers with a larger diameter exhibited a longer period of nearly zero order release, and higher drug encapsulation led to a more significant burst release after incubation. In vitro degradation showed that the smaller diameter and higher drug entrapment led to more significant changes of morphologies. The electrospun fiber mat showed almost no molecular weight reduction, but mass loss was observed for fibers with small and medium size, which was characterized with surface erosion and inconsistent with the ordinarily polymer degrading form. Further wetting behavior analysis showed that the high water repellent property of electrospun fibers led to much slower water penetration into the fiber mat, which may contribute to the degradation profiles of surface erosion. The specific degradation profile and adjustable drug release behaviors by variation of fiber characteristics made the electrospun nonwoven mat a potential drug delivery system rather than polymer films and particles. PMID:16677047

  14. Electrospun graphene-ZnO nanofiber mats for photocatalysis applications

    NASA Astrophysics Data System (ADS)

    An, Seongpil; Joshi, Bhavana N.; Lee, Min Wook; Kim, Na Young; Yoon, Sam S.

    2014-03-01

    Graphene-decorated zinc oxide (G-ZnO) nanofibers were fabricated, for the first time, by electrospinning. The effect of graphene concentration on the properties of G-ZnO mats were investigated by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and thermo gravimetric analysis. The G-ZnO mats decorated with 0.5 wt.% of graphene showed excellent photocatalytic activity through degradation of methylene blue under UV irradiation. The highest photocatalytic activity (80% degradation) was observed for 0.5 wt.% G-ZnO mats annealed at 400 °C after 4 h of UV irradiation.

  15. Fast releasing oral electrospun PVP/CD nanofiber mats of taste-masked meloxicam.

    PubMed

    Samprasit, Wipada; Akkaramongkolporn, Prasert; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Kaomongkolgit, Ruchadaporn; Opanasopit, Praneet

    2015-06-20

    Fast release and taste masking of meloxicam (MX)-loaded polyvinylpyrrolidone (PVP)/cyclodextrin (CD) nanofiber mats were developed using an electrospinning process. CDs were blended to improve the stability of the mats. The morphology and diameter of the mats were determined using scanning electron microscopy (SEM); physical and mechanical properties were also studied. The MX content, disintegration time, MX release and cytotoxicity of the mats were investigated. In vivo studies were also performed in healthy human volunteers. The results indicated that the mats were successfully prepared with fiber in the nanometer range. MX was well incorporated into the mats, with an amorphous form. The mats showed suitable tensile strength. CDs improved the physical stability by their cage-like supramolecular structure to protect from humidity and moisture, and create bead free nanofiber mats. The nanofiber mats with CDs were physically stable without any hygroscopicity and fusion. A fast disintegration and release of MX was achieved. Moreover, this mat released MX faster than the MX powder and commercial tablets. The cytotoxicity test revealed that mats were safe for a 5-min incubation. The disintegration studies indicated that in vivo disintegration agreed with the in vitro studies; the mat rapidly disintegrated in the mouth. The less bitter of MX was occurred in the mats that incorporated CD, menthol and aspartame. In addition, this mat was physical stable for 6 months. The results suggest that these mats may be a good candidate for fast dissolving drug delivery systems of bitter drugs to increase the palatability of dosage forms.

  16. Electrospun Electroactive Polymers for Aerospace Applications

    NASA Technical Reports Server (NTRS)

    Pawlowski, Kristin J.; St.Clair, Tyler L.; McReynolds, Amber C.; Park, Cheol; Ounaies, Zoubeida; Siochi, Emilie J.; Harrison, Joycelyn S.

    2003-01-01

    Electrospun piezoelectric polymers are being developed for use as a component on lightweight wings for micro-air vehicles (MAV). The goal is to incorporate fibers with tailored properties to permit dynamic control and maneuverability during flight. In particular, electrospun fiber mats of two piezoelectric polymers were investigated to ascertain their potential for the MAV application. In the work reported here, the typical experimental set-up for electrospinning was modified to induce fiber orientation in the spun mats. The morphologies of the resulting fibers and fiber mats were evaluated for various experimental conditions, and a comparison between oriented and unoriented fiber mats was carried out.

  17. New crosslinkers for electrospun chitosan fibre mats. I. Chemical analysis

    PubMed Central

    Austero, Marjorie S.; Donius, Amalie E.; Wegst, Ulrike G. K.; Schauer, Caroline L.

    2012-01-01

    Chitosan (CS), the deacetylated form of chitin, the second most abundant, natural polysaccharide, is attractive for applications in the biomedical field because of its biocompatibility and resorption rates, which are higher than chitin. Crosslinking improves chemical and mechanical stability of CS. Here, we report the successful utilization of a new set of crosslinkers for electrospun CS. Genipin, hexamethylene-1,6-diaminocarboxysulphonate (HDACS) and epichlorohydrin (ECH) have not been previously explored for crosslinking of electrospun CS. In this first part of a two-part publication, we report the morphology, determined by field emission scanning electron microscopy (FESEM), and chemical interactions, determined by Fourier transform infrared microscopy, respectively. FESEM revealed that CS could successfully be electrospun from trifluoroacetic acid with genipin, HDACS and ECH added to the solution. Diameters were 267 ± 199 nm, 644 ± 359 nm and 896 ± 435 nm for CS–genipin, CS–HDACS and CS–ECH, respectively. Short- (15 min) and long-term (72 h) dissolution tests (T600) were performed in acidic, neutral and basic pHs (3, 7 and 12). Post-spinning activation by heat and base to enhance crosslinking of CS–HDACS and CS–ECH decreased the fibre diameters and improved the stability. In the second part of this publication, we report the mechanical properties of the fibres. PMID:22628209

  18. Fabrication, characterization and biomedical application of two-nozzle electrospun polycaprolactone/zein-calcium lactate composite nonwoven mat.

    PubMed

    Liao, Nina; Joshi, Mahesh Kumar; Tiwari, Arjun Prasad; Park, Chan-Hee; Kim, Cheol Sang

    2016-07-01

    The objective of the current work is to incorporate calcium lactate (CL) into polycaprolactone (PCL)/zein composite micro/nanofibrous scaffolds via electrospinning to engineer bone tissue. In this study, a composite micro/nano fibrous scaffold was fabricated using a single two-nozzle electrospinning system to combine indicative nanofibers from a blended solution of zein-CL and micro-sized fibers from a PCL solution. Incorporation of the CL into the PCL/zein fibers were shown to improve the wettability, tensile strength and biological activity of the composite mats. Moreover, the composite mats have a high efficiency to nucleate calcium phosphate from simulated body fluid (SBF) solution. An in vitro cell culture with osteoblast cells demonstrated that the electrospun composite mats possessed improved biological properties, including a better cell adhesion, spread and proliferation. This study has demonstrated that the PCL/zein-CL composite provides a simple platform to fabricate a new biomimetic scaffold for bone tissue engineering, which can recapitulate both the morphology of extracellular matrix and composition of the bone. PMID:26919567

  19. Fabrication, characterization and biomedical application of two-nozzle electrospun polycaprolactone/zein-calcium lactate composite nonwoven mat.

    PubMed

    Liao, Nina; Joshi, Mahesh Kumar; Tiwari, Arjun Prasad; Park, Chan-Hee; Kim, Cheol Sang

    2016-07-01

    The objective of the current work is to incorporate calcium lactate (CL) into polycaprolactone (PCL)/zein composite micro/nanofibrous scaffolds via electrospinning to engineer bone tissue. In this study, a composite micro/nano fibrous scaffold was fabricated using a single two-nozzle electrospinning system to combine indicative nanofibers from a blended solution of zein-CL and micro-sized fibers from a PCL solution. Incorporation of the CL into the PCL/zein fibers were shown to improve the wettability, tensile strength and biological activity of the composite mats. Moreover, the composite mats have a high efficiency to nucleate calcium phosphate from simulated body fluid (SBF) solution. An in vitro cell culture with osteoblast cells demonstrated that the electrospun composite mats possessed improved biological properties, including a better cell adhesion, spread and proliferation. This study has demonstrated that the PCL/zein-CL composite provides a simple platform to fabricate a new biomimetic scaffold for bone tissue engineering, which can recapitulate both the morphology of extracellular matrix and composition of the bone.

  20. Electrospun chitosan/polyvinyl alcohol nanofibre mats for wound healing.

    PubMed

    Charernsriwilaiwat, Natthan; Rojanarata, Theerasak; Ngawhirunpat, Tanasait; Opanasopit, Praneet

    2014-04-01

    Chitosan (CS) aqueous salt blended with polyvinyl alcohol (PVA) nanofibre mats was prepared by electrospinning. CS was dissolved with hydroxybenzotriazole (HOBt), thiamine pyrophosphate (TPP) and ethylenediaminetetraacetic acid (EDTA) in distilled water without the use of toxic or hazardous solvents. The CS aqueous salts were blended with PVA at different weight ratios, and the effect of the solution ratios was investigated. The morphologies and mechanical and swelling properties of the generated fibres were analysed. Indirect cytotoxicity studies indicated that the CS/PVA nanofibre mats were non-toxic to normal human fibroblast cells. The CS-HOBt/PVA and CS-EDTA/PVA nanofibre mats demonstrated satisfactory antibacterial activity against both gram-positive and gram-negative bacteria, and an in vivo wound healing test showed that the CS-EDTA/PVA nanofibre mats performed better than gauze in decreasing acute wound size during the first week after tissue damage. In conclusion, the biodegradable, biocompatible and antibacterial CS-EDTA/PVA nanofibre mats have potential for use as wound dressing materials.

  1. Kafirin Protein Based Electrospun Fibers with Tunable Mechanical Property, Wettability, and Release Profile.

    PubMed

    Xiao, Jie; Shi, Ce; Zheng, Huijuan; Shi, Zhen; Jiang, Dong; Li, Yunqi; Huang, Qingrong

    2016-04-27

    Kafirin (KAF), the prolamine protein from sorghum grain, is a promising resource for fabricating renewable and biodegradable materials. However, research efforts in fulfilling its potentials are still lacking. In this work, electrospun kafirin fibers from acetic acid/dichloromethane solutions are reported for the first time. Biodegradable polycaprolactone (PCL) was blended with kafirin to obtain hybrid KAF/PCL fiber mats with desirable physical properties. Hydrogen bonding between the N-H group of kafirin and the C═O group of PCL was detected in each blended formulation. Our small-angle X-ray scattering results indicated that the long spacing decreased and the average spacing between crystalline lamellae of PCL increased with the increase of kafirin content. Compared to the hydrophobic surface of neat PCL fiber mat, KAF/PCL fiber mats under most of the blend ratios showed hydrophilic surface character, and the swelling property was composition-dependent. The fiber mats evolved from brittle ones to flexible ones with the increase of relative content of PCL. The most desirable mechanical performance was obtained at a kafirin/PCL mass blend ratio of 1:2. To simulate the nutraceutical release in body fluid, carnosic acid (CA) was selected as a nutraceutical model, and release behaviors in selected KAF/PCL fiber mats were found to be diffusion controlled. Whereas the amorphous region of kafirin dominated the release rate, PCL functioned as a hydrophobic skeleton to maintain the 3D scaffold of the fiber matrix. The fabricated KAF/PCL fiber mats open up new applications of underutilized cereal protein in nutraceutical delivery. PMID:27032442

  2. Development of Suberin Fatty Acids and Chloramphenicol-Loaded Antimicrobial Electrospun Nanofibrous Mats Intended for Wound Therapy.

    PubMed

    Tamm, Ingrid; Heinämäki, Jyrki; Laidmäe, Ivo; Rammo, Liisi; Paaver, Urve; Ingebrigtsen, Sveinung G; Škalko-Basnet, Nataša; Halenius, Anna; Yliruusi, Jouko; Pitkänen, Pauliina; Alakurtti, Sami; Kogermann, Karin

    2016-03-01

    Suberin fatty acids (SFAs) isolated from outer birch bark were investigated as an antimicrobial agent and biomaterial in nanofibrous mats intended for wound treatment. Electrospinning (ES) was used in preparing the composite nonwoven nanomats containing chloramphenicol (CAM; as a primary antimicrobial drug), SFAs, and polyvinylpyrrolidone (as a carrier polymer for ES). The X-ray powder diffraction, differential scanning calorimetry, scanning electron microscopy, atomic force microscopy, and texture analysis were used for the physicochemical and mechanical characterization of the nanomats. ES produced nanofibrous mats with uniform structure and with an average fiber diameter ranging from 370 to 425 nm. Microcrystalline SFAs and crystalline CAM were found to undergo a solid-state transformation during ES processing. The ES process caused also the loss of CAM in the final nanofibers. In the texture analysis, the SFAs containing nanofibers exhibited significantly higher maximum detachment force to an isolated pig skin (p < 0.05) than that obtained with the reference nanofibers. CAM exists in an amorphous form in the nanofibers which needs to be taken into account in controlling the physical storage stability. In conclusion, homogeneous composite nanofibrous mats for wound healing can be electrospun from the ternary mixture(s) of CAM, SFAs, and polyvinylpyrrolidone. PMID:26886306

  3. Effects of emulsion droplet size on the structure of electrospun ultrafine biocomposite fibers with cellulose nanocrystals.

    PubMed

    Li, Yingjie; Ko, Frank K; Hamad, Wadood Y

    2013-11-11

    Electrospinning of cellulose nanocrystals (CNC)/poly(lactic acid) (PLA) emulsions has been demonstrated to be an effective dispersion and alignment method to control assembly of CNC into continuous composite ultrafine fibers. CNC-PLA nanocomposite random-fiber mats and aligned-fiber yarns were prepared by emulsion electrospinning. A dispersed phase of CNC aqueous suspension and an immiscible continuous phase of PLA solution comprised the CNC-PLA water-in-oil (W/O) emulsion system. Under a set of specific conditions, the as-spun composite ultrafine fibers assumed core-shell or hollow structures. In these structures, CNCs were aligned along the core in the core-shell case, or on the wall of the hollow cylinder in the hollow fiber case. CNCs act as nucleating agents influencing PLA crystallinity, and improve the strength and stiffness of electrospun composite fibers. The effects of emulsion droplet size on fiber structural formation and CNC distribution within the electrospun fibers have been carefully examined. PMID:23789830

  4. Distributed feedback imprinted electrospun fiber lasers.

    PubMed

    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.

  5. Fast releasing oral electrospun PVP/CD nanofiber mats of taste-masked meloxicam.

    PubMed

    Samprasit, Wipada; Akkaramongkolporn, Prasert; Ngawhirunpat, Tanasait; Rojanarata, Theerasak; Kaomongkolgit, Ruchadaporn; Opanasopit, Praneet

    2015-06-20

    Fast release and taste masking of meloxicam (MX)-loaded polyvinylpyrrolidone (PVP)/cyclodextrin (CD) nanofiber mats were developed using an electrospinning process. CDs were blended to improve the stability of the mats. The morphology and diameter of the mats were determined using scanning electron microscopy (SEM); physical and mechanical properties were also studied. The MX content, disintegration time, MX release and cytotoxicity of the mats were investigated. In vivo studies were also performed in healthy human volunteers. The results indicated that the mats were successfully prepared with fiber in the nanometer range. MX was well incorporated into the mats, with an amorphous form. The mats showed suitable tensile strength. CDs improved the physical stability by their cage-like supramolecular structure to protect from humidity and moisture, and create bead free nanofiber mats. The nanofiber mats with CDs were physically stable without any hygroscopicity and fusion. A fast disintegration and release of MX was achieved. Moreover, this mat released MX faster than the MX powder and commercial tablets. The cytotoxicity test revealed that mats were safe for a 5-min incubation. The disintegration studies indicated that in vivo disintegration agreed with the in vitro studies; the mat rapidly disintegrated in the mouth. The less bitter of MX was occurred in the mats that incorporated CD, menthol and aspartame. In addition, this mat was physical stable for 6 months. The results suggest that these mats may be a good candidate for fast dissolving drug delivery systems of bitter drugs to increase the palatability of dosage forms. PMID:25899284

  6. Superhydrophobic, Hybrid, Electrospun Cellulose Acetate Nanofibrous Mats for Oil/Water Separation by Tailored Surface Modification.

    PubMed

    Arslan, Osman; Aytac, Zeynep; Uyar, Tamer

    2016-08-01

    Electrospun cellulose acetate nanofibers (CA-NF) have been modified with perfluoro alkoxysilanes (FS/CA-NF) for tailoring their chemical and physical features aiming oil-water separation purposes. Strikingly, hybrid FS/CA-NF showed that perfluoro groups are rigidly positioned on the outer surface of the nanofibers providing superhydrophobic characteristic with a water contact angle of ∼155°. Detailed analysis showed that hydrolysis/condensation reactions led to the modification of the acetylated β(1 → 4) linked d-glucose chains of CA transforming it into a superhydrophobic nanofibrous mat. Analytical data have revealed that CA-NF surfaces can be selectively controlled for fabricating the durable, robust and water resistant hybrid electrospun nanofibrous mat. The -OH groups available on the CA structure allowed the basic sol-gel reactions started by the reactive FS hybrid precursor system which can be monitored by spectroscopic analysis. Since alkoxysilane groups on the perfluoro silane compound are capable of reacting for condensation together with the CA, superhydrophobic nanofibrous mat is obtained via electrospinning. This structural modification led to the facile fabrication of the novel oil/water nanofibrous separator which functions effectively demonstrated by hexane/oil and water separation experiments. Perfluoro groups consequently modified the hydrophilic CA nanofibers into superhydrophobic character and therefore FS/CA-NF could be quite practical for future applications like water/oil separators, as well as self-cleaning or water resistant nanofibrous structures. PMID:27398738

  7. Superhydrophobic, Hybrid, Electrospun Cellulose Acetate Nanofibrous Mats for Oil/Water Separation by Tailored Surface Modification.

    PubMed

    Arslan, Osman; Aytac, Zeynep; Uyar, Tamer

    2016-08-01

    Electrospun cellulose acetate nanofibers (CA-NF) have been modified with perfluoro alkoxysilanes (FS/CA-NF) for tailoring their chemical and physical features aiming oil-water separation purposes. Strikingly, hybrid FS/CA-NF showed that perfluoro groups are rigidly positioned on the outer surface of the nanofibers providing superhydrophobic characteristic with a water contact angle of ∼155°. Detailed analysis showed that hydrolysis/condensation reactions led to the modification of the acetylated β(1 → 4) linked d-glucose chains of CA transforming it into a superhydrophobic nanofibrous mat. Analytical data have revealed that CA-NF surfaces can be selectively controlled for fabricating the durable, robust and water resistant hybrid electrospun nanofibrous mat. The -OH groups available on the CA structure allowed the basic sol-gel reactions started by the reactive FS hybrid precursor system which can be monitored by spectroscopic analysis. Since alkoxysilane groups on the perfluoro silane compound are capable of reacting for condensation together with the CA, superhydrophobic nanofibrous mat is obtained via electrospinning. This structural modification led to the facile fabrication of the novel oil/water nanofibrous separator which functions effectively demonstrated by hexane/oil and water separation experiments. Perfluoro groups consequently modified the hydrophilic CA nanofibers into superhydrophobic character and therefore FS/CA-NF could be quite practical for future applications like water/oil separators, as well as self-cleaning or water resistant nanofibrous structures.

  8. Electrospun lignin-derived carbon nanofiber mats surface-decorated with MnO2 nanowhiskers as binder-free supercapacitor electrodes with high performance

    NASA Astrophysics Data System (ADS)

    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.

  9. Electrospun ZnO/SiO2 hybrid nanofibrous mat for flexible ultraviolet sensor

    NASA Astrophysics Data System (ADS)

    Xi, Min; Wang, Xiaoxu; Zhao, Yong; Zhu, Zhengtao; Fong, Hao

    2014-03-01

    A freestanding/flexible hybrid mat consisting of crystalline ZnO nanofibers (˜75 wt. %) and amorphous SiO2 nanofibers (˜25 wt. %) was prepared by the technique of electrospinning followed by the pyrolysis in air at 650 °C. The electrospun ZnO/SiO2 hybrid mat was then studied to fabricate a flexible ultraviolet (UV) sensor, and the photo-response of this sensor was characterized under varied UV light intensities; additionally, the sensor performance under the bending condition was also evaluated. The results indicated that the flexible UV sensor had excellent sensitivity and reproducibility/reversibility, and it also exhibited high performance under the bending condition.

  10. Electrospun polystyrene fiber diameter influencing bacterial attachment, proliferation, and growth.

    PubMed

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

    2015-04-15

    Electrospun materials have been widely investigated in the past few decades as candidates for tissue engineering applications. However, there is little available data on the mechanisms of interaction of bacteria with electrospun wound dressings of different morphology and surface chemistry. This knowledge could allow the development of effective devices against bacterial infections in chronic wounds. In this paper, the interactions of three bacterial species (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) with electrospun polystyrene meshes were investigated. Bacterial response to meshes with different fiber diameters was assessed through a combination of scanning electron microscopy (SEM) and confocal microscopy. Experiments included attachment studies in liquid medium but also directly onto agar plates; the latter was aimed at mimicking a chronic wound environment. Fiber diameter was shown to affect the ability of bacteria to proliferate within the fibrous networks, depending on cell size and shape. The highest proliferation rates occurred when fiber diameter was close to the bacterial size. Nanofibers were found to induce conformational changes of rod shaped bacteria, limiting the colonization process and inducing cell death. The data suggest that simply tuning the morphological properties of electrospun fibers may be one strategy used to control biofilm formation within wound dressings.

  11. Electrospun Fibers as a Scaffolding Platform for Bone Tissue Repair

    PubMed Central

    Lyu, Seungyoun; Huang, Chunlan; Yang, Hong; Zhang, Xinping

    2014-01-01

    The purpose of the study is to investigate the effects of electrospun fiber diameter and orientation on differentiation and ECM organization of bone marrow stromal cells (BMSCs), in attempt to provide rationale for fabrication of a periosteum mimetic for bone defect repair. Cellular growth, differentiation, and ECM organization were analyzed on PLGA-based random and aligned fibers using fluorescent microscopy, gene analyses, electron scanning microscopy (SEM), and multiphoton laser scanning microscopy (MPLSM). BMSCs on aligned fibers had a reduced number of ALP+ colony at day 10 as compared to the random fibers of the same size. However, the ALP+ area in the aligned fibers increased to a similar level as the random fibers at day 21 following stimulation with osteogenic media. Compared with the random fibers, BMSCs on the aligned fibers showed a higher expression of OSX and RUNX2. Analyses of ECM on decellularized spun fibers showed highly organized ECM arranged according to the orientation of the spun fibers, with a broad size distribution of collagen fibers in a range of 40nm to 2.4µm. Taken together, our data support the use of submicron-sized electrospun fibers for engineering of oriented fibrous tissue mimetic, such as periosteum, for guided bone repair and reconstruction. PMID:23580466

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

    PubMed

    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. PMID:27432415

  13. Preparation and characterization of electrospun poly(3-hydroxybutyrate-co-3-hydroxyvalerate) fibrous mats

    NASA Astrophysics Data System (ADS)

    Xu, Yongjing; Zou, Liming; Lu, Hongwei; Chen, Zailing

    2015-07-01

    Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), as a biodegradable polyester, was electrospun to obtain defect-free fibers with high surface-area-to-volume ratio. Several parameters such as solvent ratio, polymer concentration, applied voltage, flow rate, and tip-to-target distance were optimized to achieve defect-free morphology. The average diameter of the PHBV fibers was 1400 nm. In order to evaluate the final properties of PHBV nanofibers, the following characterization techniques were employed: scanning electron microscopy (SEM), Fourier transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy, uniaxial tensile tests and dataphysics instruments.

  14. Coaxial electrospun fibers: applications in drug delivery and tissue engineering.

    PubMed

    Lu, Yang; Huang, Jiangnan; Yu, Guoqiang; Cardenas, Romel; Wei, Suying; Wujcik, Evan K; Guo, Zhanhu

    2016-09-01

    Coelectrospinning and emulsion electrospinning are two main methods for preparing core-sheath electrospun nanofibers in a cost-effective and efficient manner. Here, physical phenomena and the effects of solution and processing parameters on the coaxial fibers are introduced. Coaxial fibers with specific drugs encapsulated in the core can exhibit a sustained and controlled release. Their exhibited high surface area and three-dimensional nanofibrous network allows the electrospun fibers to resemble native extracellular matrices. These features of the nanofibers show that they have great potential in drug delivery and tissue engineering applications. Proteins, growth factors, antibiotics, and many other agents have been successfully encapsulated into coaxial fibers for drug delivery. A main advantage of the core-sheath design is that after the process of electrospinning and release, these drugs remain bioactive due to the protection of the sheath. Applications of coaxial fibers as scaffolds for tissue engineering include bone, cartilage, cardiac tissue, skin, blood vessels and nervous tissue, among others. A synopsis of novel coaxial electrospun fibers, discussing their applications in drug delivery and tissue engineering, is covered pertaining to proteins, growth factors, antibiotics, and other drugs and applications in the fields of bone, cartilage, cardiac, skin, blood vessel, and nervous tissue engineering, respectively. WIREs Nanomed Nanobiotechnol 2016, 8:654-677. doi: 10.1002/wnan.1391 For further resources related to this article, please visit the WIREs website. PMID:26848106

  15. Mechanical Behavior of Electrospun Palmfruit Bunch Reinforced Polylactide Composite Fibers

    NASA Astrophysics Data System (ADS)

    Adeosun, S. O.; Akpan, E. I.; Gbenebor, O. P.; Peter, A. A.; Olaleye, Samuel Adebayo

    2016-01-01

    In this study, the mechanical characteristics of electrospun palm fruit bunch reinforced poly lactic acid (PLA) nanofiber composites using treated and untreated filler was examined. Poly lactic acid-palm fruit bunch-dichloromethane blends were electrospun by varying the concentration of the palm fruit bunch between 0 wt.% and 8 wt.%. A constant voltage of 26 kV was applied, the tip-to-collector distance was maintained at 27.5 cm and PLA-palm fruit bunch-dichloromethane (DCM) concentration of 12.5% (w/v) was used. The results revealed that the presence of untreated palm fruit bunch fillers in the electrospun PLA matrix significantly reduces the average diameters of the fibers, causing the formation of beads. As a result there are reductions in tensile strengths of the fibers. The presence of treated palm fruit bunch fillers in the electrospun PLA matrix increases the average diameters of the fibers with improvements in the mechanical properties. The optimal mechanical responses were obtained at 3 wt.% of the treated palm fruit bunch fillers in the PLA matrix. However, increase in the palm fruit fillers (treated and untreated) in the PLA matrix promoted the formation of beads in the nanofiber composites.

  16. Formation and Biopharmaceutical Characterization of Electrospun PVP Mats with Propolis and Silver Nanoparticles for Fast Releasing Wound Dressing

    PubMed Central

    Adomavičiūtė, Erika; Stanys, Sigitas; Žilius, Modestas; Juškaitė, Vaida; Pavilonis, Alvydas; Briedis, Vitalis

    2016-01-01

    Antibacterial, antiviral, antifungal, antioxidant, anti-inflammatory, and anticancer activities of propolis and its ability to stimulate the immune system and promote wound healing make it a proper component for wound dressing materials. Silver nanoparticles are recognized to demonstrate strong antiseptic and antimicrobial activity; thus, it also could be considered in the development of products for wound healing. Combining propolis and silver nanoparticles can result in improved characteristics of products designed for wound healing and care. The aim of this study was to formulate electrospun fast dissolving mats for wound dressing containing propolis ethanolic extract and silver nanoparticles. Produced electrospun nano/microfiber mats were evaluated studying their structure, dissolution rate, release of propolis phenolic compounds and silver nanoparticles, and antimicrobial activity. Biopharmaceutical characterization of electrospun mats demonstrated fast release of propolis phenolic compounds and silver nanoparticles. Evaluation of antimicrobial activity on Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Bacillus subtilis, Bacillus cereus, and Candida albicans strains confirmed the ability of electrospun mats to inhibit the growth of the tested microorganisms. PMID:26981531

  17. Formation and Biopharmaceutical Characterization of Electrospun PVP Mats with Propolis and Silver Nanoparticles for Fast Releasing Wound Dressing.

    PubMed

    Adomavičiūtė, Erika; Stanys, Sigitas; Žilius, Modestas; Juškaitė, Vaida; Pavilonis, Alvydas; Briedis, Vitalis

    2016-01-01

    Antibacterial, antiviral, antifungal, antioxidant, anti-inflammatory, and anticancer activities of propolis and its ability to stimulate the immune system and promote wound healing make it a proper component for wound dressing materials. Silver nanoparticles are recognized to demonstrate strong antiseptic and antimicrobial activity; thus, it also could be considered in the development of products for wound healing. Combining propolis and silver nanoparticles can result in improved characteristics of products designed for wound healing and care. The aim of this study was to formulate electrospun fast dissolving mats for wound dressing containing propolis ethanolic extract and silver nanoparticles. Produced electrospun nano/microfiber mats were evaluated studying their structure, dissolution rate, release of propolis phenolic compounds and silver nanoparticles, and antimicrobial activity. Biopharmaceutical characterization of electrospun mats demonstrated fast release of propolis phenolic compounds and silver nanoparticles. Evaluation of antimicrobial activity on Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Bacillus subtilis, Bacillus cereus, and Candida albicans strains confirmed the ability of electrospun mats to inhibit the growth of the tested microorganisms.

  18. Effect of photografting 2-hydroxyethyl acrylate on the hemocompatibility of electrospun poly(ethylene-co-vinyl alcohol) fibroporous mats.

    PubMed

    Mayuri, P V; Bhatt, Anugya; Joseph, Roy; Ramesh, P

    2016-03-01

    Poly(ethylene-co-vinyl alcohol) (EVAL) has been recommended as a material suitable for blood contacting applications. Effect of ethylene content and associated hydrophobicity of EVAL on the blood-material interactions have been documented in the literature. In this work, surface chemistry of EVAL substrate was altered by photografting a hydrophilic monomer, 2-hydroxyethyl acrylate (HEA) with the aid of a photoinitiator, benzophenone (BP), and the effect of surface modification on the blood-material interactions was investigated. Since the modified material was intended to be used as leukodepletion filters, a solution containing EVAL, HEA and BP was electrospun into fibroporous mats and UV treated to induce grafting. Degree of grafting, bonding between fibers and fiber diameter increased with increase in UV exposure time whereas mechanical properties showed a decreasing trend. Decreased water contact angle indicated improved wetting characteristics. In vitro hemocompatibility tests revealed that the modified EVAL surface exhibited significantly lower hemolytic activity, protein adsorption and platelet adhesion than neat EVAL. The modification did not have any substantial effect on the activation of the complement system and coagulation parameters. Photografting led to significant reduction in the adhesion of red blood cells (RBC) whereas white blood cell (WBC) consumption remained above 90%. The results implied that photografting HEA on EVAL substantially improves hemocompatibility of EVAL and when it is used as a filter, it selectively removes leukocytes and allows easy passage of other blood components. PMID:26706502

  19. Carbon fibers from electrospun polymeric phenolic resin precursors

    NASA Astrophysics Data System (ADS)

    Gee, Diane L.

    This dissertation presents a technique for producing carbon fibers of nano- to micro-sized dimension by utilizing a non-conventional fiber spinning approach with refractory polymers, followed by post-processing steps, to create new carbon materials with distinctive chemical/physical property characteristics. Phenolic resins, novolak and resole, are selected for this study because of their low cost, marketability, environmental friendliness, and high char yield upon pyrolysis. The new carbon fibers are at least an order of magnitude smaller than their conventionally processed counterpart, and possess significant advantages. Phenolic resin fibers, consisting of a blend of novolak and resole, are generated via electrospinning and are subsequently cured and pyrolyzed at temperatures from 800°C to 2000°C to form carbon fibers having diameters of ˜1 mum. Fiber analysis by scanning electron microscopy confirms that the morphology generated during the electrospinning processing is retained throughout the curing and carbonization processes. X-ray diffraction suggests the presence of highly graphitized carbon, which is further validated by high-resolution transmission electron microscopy (HRTEM) analysis. There is evidence of crystalline graphite, which may have nucleated on aligned sheets presence on the fiber surface. The physical characteristics of electrospun fibers are contrary to those exhibited by pyrolyzed phenolic resins, which fall into the classification of non-graphitizing. It is likely that the thin electrospun fibers offer a template that encourages ordering not usually seen in thicker fibers or bulk samples of carbonized phenolic resins.

  20. Effects of Humidity and Solution Viscosity on Electrospun Fiber Morphology

    PubMed Central

    Nezarati, Roya M.; Eifert, Michelle B.

    2013-01-01

    Electrospinning is a popular technique to fabricate tissue engineering scaffolds due to the exceptional tunability of fiber morphology that can be used to control scaffold mechanical properties, degradation rate, and cell behavior. Although the effects of modulating processing or solution parameters on fiber morphology have been extensively studied, there remains limited understanding of the impact of environmental parameters such as humidity. To address this gap, three polymers (poly(ethylene glycol) [PEG], polycaprolactone [PCL], and poly(carbonate urethane) [PCU]) were electrospun at a range of relative humidities (RH=5%–75%) and the resulting fiber architecture characterized with scanning electron microscopy. Low relative humidity (<50%) resulted in fiber breakage for all three polymers due to decreased electrostatic discharge from the jet. At high relative humidity (>50%), three distinct effects were observed based on individual polymer properties. An increase in fiber breakage and loss of fiber morphology occurred in the PEG system as a result of increased water absorption at high relative humidity. In contrast, surface pores on PCL fibers were observed and hypothesized to have formed via vapor-induced phase separation. Finally, decreased PCU fiber collection occurred at high humidity likely due to increased electrostatic discharge. These findings highlight that the effects of relative humidity on electrospun fiber morphology are dependent on polymer hydrophobicity, solvent miscibility with water, and solvent volatility. An additional study was conducted to highlight that small changes in molecular weight can strongly influence solution viscosity and resulting fiber morphology. We propose that solution viscosity rather than concentration is a more useful parameter to report in electrospinning methodology to enable reproduction of findings. In summary, this study further elucidates key mechanisms in electrospun fiber formation that can be utilized to

  1. Conversion of an electrospun nanofibrous cellulose acetate mat from a super-hydrophilic to super-hydrophobic surface

    NASA Astrophysics Data System (ADS)

    Ding, Bin; Li, Chunrong; Hotta, Yoshio; Kim, Jinho; Kuwaki, Oriha; Shiratori, Seimei

    2006-09-01

    We report a new approach to convert an electrospun nanofibrous cellulose acetate mat surface from super-hydrophilic to super-hydrophobic. Super-hydrophilic cellulose acetate nanofibrous mats can be obtained by electrospinning hydrophilic cellulose acetate. The surface properties of the fibrous mats were modified from super-hydrophilic to super-hydrophobic with a simple sol-gel coating of decyltrimethoxysilane (DTMS) and tetraethyl orthosilicate (TEOS). The resultant samples were characterized by field emission scanning electron microscopy (FE-SEM), x-ray photoelectron spectroscopy (XPS), water contact angle, Brunauer-Emmett-Teller (BET) surface area, atomic force microscopy (AFM), and UV-visible measurements. The results of FE-SEM and XPS showed that the sol-gel (I) films were formed on the rough fibrous mats only after immersion in sol-gel. After the sol-gel (I) coating, the cellulose acetate fibrous mats formed in both 8 and 10 wt% cellulose acetate solutions showed the super-hydrophobic surface property. Additionally, the average sol-gel film thickness coated on 10 wt% cellulose acetate fibrous mats was calculated to be 80 nm. The super-hydrophobicity of fibrous mats was attributed to the combined effects of the high surface roughness of the electrospun nanofibrous mats and the hydrophobic DTMS sol-gel coating. Additionally, hydrophobic sol-gel nanofilms were found to be transparent according to UV-visible measurements.

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

    NASA Technical Reports Server (NTRS)

    Kohlman, Lee W.

    2013-01-01

    Toughening and other property enhancements of composite materials are typically implemented by-modifying the bulk properties of the constituents, either the fiber or matrix materials. This often leads to difficulties in processing and higher material costs. Many composites consist of tows or yarns (thousands of individual fibers) that are either filament wound or processed into a fabric by weaving or braiding. The matrix material can be added to the tow or fabric before final processing, resulting in a prepreg material, or infused into the fiber material during final processing by a variety of methods. By using a direct electrospun deposition method to apply thermoplastic nanofiber to the surface of the tows, the tow-tow interface in the resulting composite can be modified while using otherwise conventional materials and handling processes. Other materials of interest could also be incorporated into the electrospun precursor.

  3. Improved Cellular Infiltration in Electrospun Fiber via Engineered Porosity

    PubMed Central

    NAM, JIN; HUANG, YAN; AGARWAL, SUDHA; LANNUTTI, JOHN

    2016-01-01

    Small pore sizes inherent to electrospun matrices can hinder efficient cellular ingrowth. To facilitate infiltration while retaining its extracellular matrix-like character, electrospinning was combined with salt leaching to produce a scaffold having deliberate, engineered delaminations. We made elegant use of a specific randomizing component of the electrospinning process, the Taylor Cone and the falling fiber beneath it, to produce a uniform, well-spread distribution of salt particles. After 3 weeks of culture, up to 4 mm of cellular infiltration was observed, along with cellular coverage of up to 70% within the delaminations. To our knowledge, this represents the first observation of extensive cellular infiltration of electrospun matrices. Infiltration appears to be driven primarily by localized proliferation rather than coordinated cellular locomotion. Cells also moved from the salt-generated porosity into the surrounding electrospun fiber matrix. Given that the details of salt deposition (amount, size, and number density) are far from optimized, the result provides a convincing illustration of the ability of mammalian cells to interact with appropriately tailored electrospun matrices. These layered structures can be precisely fabricated by varying the deposition interval and particle size conceivably to produce in vivo-like gradients in porosity such that the resulting scaffolds better resemble the desired final structure. PMID:17536926

  4. Wound-dressing materials with antibacterial activity from electrospun polyurethane-dextran nanofiber mats containing ciprofloxacin HCl.

    PubMed

    Unnithan, Afeesh R; Barakat, Nasser A M; Pichiah, P B Tirupathi; Gnanasekaran, Gopalsamy; Nirmala, R; Cha, Youn-Soo; Jung, Che-Hun; El-Newehy, Mohamed; Kim, Hak Yong

    2012-11-01

    Dextran is a versatile biomacromolecule for preparing electrospun nanofibrous membranes by blending with either water-soluble bioactive agents or hydrophobic biodegradable polymers for biomedical applications. In this study, an antibacterial electrospun scaffold was prepared by electrospinning of a solution composed of dextran, polyurethane (PU) and ciprofloxacin HCl (CipHCl) drug. The obtained nanofiber mats have good morphology. The mats were characterized by various analytical techniques. The interaction parameters between fibroblasts and the PU-dextran and PU-dextran-drug scaffolds such as viability, proliferation, and attachment were investigated. The results indicated that the cells interacted favorably with the scaffolds especially the drug-containing one. Moreover, the composite mat showed good bactericidal activity against both of Gram-positive and Gram-negative bacteria. Overall, our results conclude that the introduced scaffold might be an ideal biomaterial for wound dressing applications.

  5. Electrospun submicron bioactive glass fibers for bone tissue scaffold.

    PubMed

    Lu, H; Zhang, T; Wang, X P; Fang, Q F

    2009-03-01

    Submicron bioactive glass fibers 70S30C (70 mol% SiO(2), 30 mol% CaO) acting as bone tissue scaffolds were fabricated by electrospinning method. The scaffold is a hierarchical pore network that consists of interconnected fibers with macropores and mesopores. The structure, morphological characterization and mechanical properties of the submicron bioactive glass fibers were studied by XRD, EDS, FIIR, SEM, N(2) gas absorption analyses and nanoindentation. The effect of the voltage on the morphology of electrospun bioactive glass fibers was investigated. It was found that decreasing the applied voltage from 19 to 7 kV can facilitate the formation of finer fibers with fewer bead defects. The hardness and Young's modulus of submicron bioactive glass fibers were measured as 0.21 and 5.5 GPa, respectively. Comparing with other bone tissue scaffolds measured by nanoindentation, the elastic modulus of the present scaffold was relatively high and close to the bone.

  6. Optimization and characterization of poly(phthalazinone ether ketone) (PPEK) heat-resistant porous fiberous mat by electrospinning

    NASA Astrophysics Data System (ADS)

    Shi, R.; Bin, Y. Z.; Yang, W. X.; Wang, D.; Wang, J. Y.; Jian, X. G.

    2016-08-01

    Poly(phthalazinone ether ketone) (PPEK) is noted for its outstanding heat-resistance property and mechanical strength. A one-step electrospinning method was conducted to produce PPEK micro-nano porous fibrous mat. We gave emphasis study on the spinnability, optimized conditions, fibers' morphology, surface science and fracture mechanism. The uniform electrospun fibrous mat resulted from PPEK/chloroform binary system indicated that PPEK would be a prospective material to be applied in electrospinning. Addition of a small amount of non-solvent (ethanol) turned out to be advantageous to the reduction of fiber diameter and the alleviation of choking during spinning process. Organic salt (benzyltrimethylammonium chloride) was employed to increase the conductivity of solution for the formation of thin fiber. After trials, PPEK/chloroform/ethanol system with salt and PPEK/NMP system were taken as two optimized systems. These two systems showed different pore fraction in N2 adsorption test, and displayed different mechanical behaviors in uniaxial tension test. The fibrous mat from PPEK/chloroform/ethanol system showed a feature of ductile fracture with relatively low fracture strength but long fracture deformation, while the fibrous mat from PPEK/NMP system showed a feature of brittle fracture with small deformation but quite large fracture strength of ca. 6 MPa. Finally thermogravimetric analysis indicated that the resultant PPEK fibrous mat did not decompose until the temperature reached 478 °C, which qualified the resultant fibrous mat as a promising material used under high-temperature condition.

  7. Crosslinked Electro-Spun Chitosan Nanofiber Mats with Cd(II) as Template Ions for Adsorption Applications.

    PubMed

    Li, Yan; Xu, Cong; Qiu, Tianbao; Xu, Xiaoyan

    2015-06-01

    The Cd(II) ion imprinting electro-spun crosslinked chitosan nanofiber mats were successfully prepared using Cd(II) as template ions and glutaraldehyde (GA) as crosslinker to investigate the adsorption of Cd(II) and Pb(II) ions in aqueous solutions. The Cd(II) ion imprinting electro-spun crosslinked chitosan nanofiber mats were characterized by the Fourier Transform Infrared Spectrometer (FTIR), Scanning Electron Microscope (SEM), Thermal Gravimetric Analysis (TGA), elemental analysis and solubility tests. The prepared chitosan nanofiber mats exhibited a higher adsorption capacity for both Cd(II) (364.3 mg/g) and Pb(II) (272.0 mg/g) ions. The dynamic study demonstrated that the adsorption process followed the second-order kinetic equation. Langmuir and Freundlich adsorption models were used to analyze the equilibrium isotherm data. The results showed that the Langmuir model was best suitable for predicting the adsorption isotherm of the studied system. The as prepared Cd(II) ion imprinting electro-spun crosslinked chitosan nanofiber mats might be used as an effective adsorbent for Cd(II) and Pb(II) removal from heavy metal wastewater. PMID:26369036

  8. Electrospun cellulose nitrate and polycaprolactone blended nanofibers

    NASA Astrophysics Data System (ADS)

    Nartker, Steven; Hassan, Mohamed; Stogsdill, Michael

    2015-03-01

    Pure cellulose nitrate (CN) and blends of CN and polycaprolactone were electrospun to form nonwoven mats. Polymers were dissolved in a mixed solvent system of tetrahydrofuran and N,N-dimethylformamide. The concentrations were varied to obtain sub-micron and nanoscale fiber mats. Fiber mats were analyzed using scanning electron microscopy, contact angle analysis, Fourier transform infrared spectroscopy and thermal gravimetric analysis. The fiber morphology, surface chemistry and contact angle data show that these electrospun materials are suitable for applications including biosensing, biomedical and tissue engineering.

  9. Electrospun fibers for the prevention of human immunodeficiency virus

    NASA Astrophysics Data System (ADS)

    Ball, Cameron

    HIV/AIDS education, testing, and treatment have thus far failed to cease the pandemic spread of the HIV virus. HIV prevention is hindered by a lack of protective options beyond the ABC approach of abstinence, being faithful, and using condoms. One approach to address this inadequacy is to develop antiviral products for vaginal or rectal application that provide receptive partner-initiated protection against viral infection during sex. Such products, termed anti-HIV microbicides, can especially empower young women to take control over their sexual health. This work explored a new approach to anti-HIV microbicides: electrospun fibers for the delivery of small-molecule antiretroviral drugs. Electrospun microbicides are nonwoven fabrics made from polymer-based nanofibers. The wide array of polymers available for electrospinning allowed for the incorporation and release of chemically diverse agents. Since electrospun fibers have an extremely high surface area to volume ratio, they serve as excellent delivery systems for rapid drug delivery of both hydrophilic and hydrophobic agents. The flexibility in the design of electrospun fibers afforded by coaxial electrospinning further enabled the formulation of sustained-release microbicides. To demonstrate the power of electrospinning to deliver drugs over multiple timescales, composite microbicide fabrics were created to provide both rapid and sustained drug release from a single device. This work has produced alternative microbicide formulations, while establishing methods for the thorough characterization of these systems and solutions for the needs of people at risk of HIV infection. By addressing problems in both HIV prevention and drug delivery, this work has expanded our capacity to engineer elegant solutions to complex and pressing global health challenges.

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

    NASA Technical Reports Server (NTRS)

    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.

  11. Morphological and mechanical analysis of electrospun shape memory polymer fibers

    NASA Astrophysics Data System (ADS)

    Budun, Sinem; İşgören, Erkan; Erdem, Ramazan; Yüksek, Metin

    2016-09-01

    Shape memory block co-polymer Polyurethane (PU) fibers were fabricated by electrospinning technique. Four different solution concentrations (5 wt.%, 10 wt.%, 15 wt.% and 20 wt.%) were prepared by using Tetrahydrofuran (THF)/N,N-dimethylformamide (DMF) (50:50, v/v) as solvents, and three different voltages (30 kV, 35 kV and 38.9 kV) were determined for the electrospinning process. Solution properties were explored in terms of viscosity and electrical conductivity. It was observed that as the polymer concentration increased in the solution, the conductivity declined. Morphological characteristics of the obtained fibers were analyzed through Scanning Electron Microscopy (SEM) measurements. Findings indicated that fiber morphology varied especially with polymer concentration and applied voltage. Obtained fiber diameter ranged from 112 ± 34 nm to 2046 ± 654 nm, respectively. DSC analysis presented that chain orientation of the polymer increased after electrospinning process. Shape fixity and shape recovery calculations were realized. The best shape fixity value (92 ± 4%) was obtained for Y10K30 and the highest shape recovery measurement (130 ± 4%) was belonged to Y15K39. Mechanical properties of the electrospun webs were also investigated in both machine and transverse directions. Tensile and elongation values were also affected from fiber diameter distribution and morphological characteristics of the electrospun webs.

  12. Electrospun non-woven nanofibrous hybrid mats based on chitosan and PLA for wound-dressing applications.

    PubMed

    Ignatova, Milena; Manolova, Nevena; Markova, Nadya; Rashkov, Iliya

    2009-01-01

    Continuous defect-free nanofibers containing chitosan (Ch) or quaternized chitosan (QCh) were successfully prepared by one-step electrospinning of Ch or QCh solutions mixed with poly[(L-lactide)-co-(D,L-lactide)] in common solvent. XPS revealed the surface chemical composition of the bicomponent electrospun mats. Crosslinked Ch- and QCh-containing nanofibers exhibited higher kill rates against bacteria S. aureus and E. coli than the corresponding solvent-cast films. SEM observations showed that hybrid mats were very effective in suppressing the adhesion of pathogenic bacteria S. aureus. The hybrid nanofibers are promising for wound-healing applications.

  13. Electrospun fibers based on Arabic, karaya and kondagogu gums.

    PubMed

    Padil, Vinod Vellora Thekkae; Senan, Chandra; Wacławek, Stanisław; Černík, Miroslav

    2016-10-01

    Nanofibers of natural tree polysaccharides based on three gums namely Arabic (GA), karaya (GK) and kondagogu (KG) have been prepared for the first time using electrospinning. Electrospinning solutions were prepared by mixing gum solutions of GA, GK & KG with eco-friendly polymers such as polyvinyl alcohol (PVA) or polyethylene oxide (PEO). The present study focuses on the effect of electrospinning blended solutions of GA, GK or KG with PVA or PEO, additives which influence system parameters and process parameters. This has important effects on the electrospinning process and the resulting fibers whose morphology and physicochemical properties were evaluated. The mass ratios of 70:30 to 90:10 for PVA: GA, PVA: GK and PVA: KG were observed to establish an optimum blend solution ratio in order to fabricate uniform beadless nanofibers with an average diameter of 240±50, 220±40 and 210±30nm, respectively. Various structural and physicochemical properties of the electrospun fibers were investigated. Furthermore, the comparisons of various functionalities of the untreated and plasma treated electrospun fibers were assessed. The methane plasma treated nanofibers were shown to be of extremely specific surface area, improved water contact angle, high surface porosity and roughness and superior hydrophobic properties compared to untreated fibers. PMID:27212218

  14. Electrospun fibers based on Arabic, karaya and kondagogu gums.

    PubMed

    Padil, Vinod Vellora Thekkae; Senan, Chandra; Wacławek, Stanisław; Černík, Miroslav

    2016-10-01

    Nanofibers of natural tree polysaccharides based on three gums namely Arabic (GA), karaya (GK) and kondagogu (KG) have been prepared for the first time using electrospinning. Electrospinning solutions were prepared by mixing gum solutions of GA, GK & KG with eco-friendly polymers such as polyvinyl alcohol (PVA) or polyethylene oxide (PEO). The present study focuses on the effect of electrospinning blended solutions of GA, GK or KG with PVA or PEO, additives which influence system parameters and process parameters. This has important effects on the electrospinning process and the resulting fibers whose morphology and physicochemical properties were evaluated. The mass ratios of 70:30 to 90:10 for PVA: GA, PVA: GK and PVA: KG were observed to establish an optimum blend solution ratio in order to fabricate uniform beadless nanofibers with an average diameter of 240±50, 220±40 and 210±30nm, respectively. Various structural and physicochemical properties of the electrospun fibers were investigated. Furthermore, the comparisons of various functionalities of the untreated and plasma treated electrospun fibers were assessed. The methane plasma treated nanofibers were shown to be of extremely specific surface area, improved water contact angle, high surface porosity and roughness and superior hydrophobic properties compared to untreated fibers.

  15. A controlled release system of titanocene dichloride by electrospun fiber and its antitumor activity in vitro.

    PubMed

    Chen, Ping; Wu, Qing-Sheng; Ding, Ya-Ping; Chu, Maoquan; Huang, Zheng-Ming; Hu, Wen

    2010-11-01

    In order to improve both safety and efficacy of cancer chemotherapy of titanocene dichloride and overcome the shortcomings such as instability and short half-life in the human body, we report a controlled release system of titanocene dichloride by electrospun fiber and its in vitro antitumor activity against human lung tumor spca-1 cells. The system was developed by electrospinning. The release profiles of titanocene dichloride in PBS were researched by UV-Vis spectrophotometer. In vitro antitumor activities of the fibers were examined by MTT method. Titanocene dichloride was well incorporated in biodegradable poly(L-lactic acid) fibers. XRD results suggest that titanocene dichloride exists in the amorphous form in the fibers. The controlled release of titanocene dichloride can be gained for long time. MTT showed actual titanocene dichloride content 40, 80, 160 and 240 mg/L from the fibers mat, cell growth inhibition rates of 11.2%, 22.1%, 44.2% and 68.2% were achieved, respectively. The titanocene dichloride released has obvious inhibition effect against lung tumor cells. The system has an effect of controlled release of titanocene dichloride and may be used as an implantable anticancer drug in clinical applications in the future.

  16. Poly(L-lactide)/halloysite nanotube electrospun mats as dual-drug delivery systems and their therapeutic efficacy in infected full-thickness burns.

    PubMed

    Zhang, Xiazhi; Guo, Rui; Xu, Jiqing; Lan, Yong; Jiao, Yanpeng; Zhou, Changren; Zhao, Yaowu

    2015-11-01

    In this study, poly(L-lactide) (PLLA)/halloysite nanotube (HNT) electrospun mats were prepared as a dual-drug delivery system. HNTs were used to encapsulate polymyxin B sulphate (a hydrophilic drug). Dexamethasone (a hydrophobic drug) was directly dissolved in the PLLA solution. The drug-loaded HNTs with optimised encapsulation efficiency were then mixed with the PLLA solution for subsequent electrospinning to form composite dual-drug-loaded fibre mats. The structure, morphology, degradability and mechanical properties of the electrospun composite mats were characterised in detail. The results showed that the HNTs were uniformly distributed in the composite PLLA mats. The HNTs content in the mats could change the morphology and average diameter of the electrospun fibres. The HNTs improved both the tensile strength of the PLLA electrospun mats and their degradation ratio. The drug-release kinetics of the electrospun mats were investigated using ultraviolet-visible spectrophotometry. The HNTs/PLLA ratio could be varied to adjust the release of polymyxin B sulphate and dexamethasone. The antibacterial activity in vitro of the mats was evaluated using agar diffusion and turbidimetry tests, which indicated the antibacterial efficacy of the dual-drug delivery system against Gram-positive and -negative bacteria. Healing in vivo of infected full-thickness burns and infected wounds was investigated by macroscopic observation, histological observation and immunohistochemical staining. The results indicated that the electrospun mats were capable of co-loading and co-delivering hydrophilic and hydrophobic drugs, and could potentially be used as novel antibacterial wound dressings.

  17. Formation and characterization of magnetic barium ferrite hollow fibers with low coercivity via co-electrospun

    NASA Astrophysics Data System (ADS)

    Liu, Gui-fang; Zhang, Zi-dong; Dang, Feng; Cheng, Chuan-bing; Hou, Chuan-xin; Liu, Si-da

    2016-08-01

    BaFe12O19 fibers and hollow fibers were successfully prepared by electrospun and co-electrospun. A very interesting result appeared in this study that hollow fibers made by co-electrospun showed low coercivity values of a few hundred oersteds, compared with the coercivity values of more than thousand oersteds for the fibers made by electrospun. So the hollow fibers with high saturation magnetization (Ms) and while comparatively low coercivity (Hc) exhibited strong magnetism and basically showed soft character. And this character for hollow fibers will lead to increase of the permeability for the samples which is favorable for impedance matching in microwave absorption. So these hollow fibers are promised to have use in a number of applications, such as switching and sensing applications, electromagnetic materials, microwave absorber.

  18. Encapsulation of living bifidobacteria in ultrathin PVOH electrospun fibers.

    PubMed

    López-Rubio, Amparo; Sanchez, Ester; Sanz, Yolanda; Lagaron, Jose M

    2009-10-12

    This study shows the application of the electrospinning technique as a viable method for the encapsulation and stabilization of bifidobacterial strains. Poly(vinyl alcohol) (PVOH) was used as the encapsulating material because it is generally recognized as safe (GRAS), has a high oxygen barrier when dry, and is water soluble, hence allowing easy recovery of the bacteria for viability testing. A coaxial setup was used for encapsulation, and the so-obtained electrospun fibers had a mean diameter of ca. 150 nm. Incorporation of B. animalis Bb12 led to a decrease in melting point and crystallinity of the PVOH fibers and to an increase in the polymer glass transition temperature. The viability tests, carried out at three different temperatures (room temperature and 4 and -20 degrees C) showed that B. animalis Bb12 encapsulated within the electrospun PVOH fibers remained viable for 40 days at room temperature and for 130 days at refrigeration temperature, whereas a significant viability decrease was observed in both cases when bacteria were not encapsulated (p = 0.015 and p = 0.002, respectively). PMID:19817490

  19. Engineering blood vessels through micropatterned co-culture of vascular endothelial and smooth muscle cells on bilayered electrospun fibrous mats with pDNA inoculation.

    PubMed

    Liu, Yaowen; Lu, Jinfu; Li, Huinan; Wei, Jiaojun; Li, Xiaohong

    2015-01-01

    Although engineered blood vessels have seen important advances during recent years, proper mechanical strength and vasoactivity remain unsolved problems. In the current study, micropatterned fibrous mats were created to load smooth muscle cells (SMC), and a co-culture with endothelial cells (EC) was established through overlaying on an EC-loaded flat fibrous mat to mimic the layered structure of a blood vessel. A preferential distribution of SMC was determined in the patterned regions throughout the fibrous scaffolds, and aligned fibers in the patterned regions provided topological cues to guide the orientation of SMC with intense actin filaments and extracellular matrix (ECM) production in a circumferential direction. Plasmid DNA encoding basic fibroblast growth factors and vascular endothelial growth factor were integrated into electrospun fibers as biological cues to promote SMC infiltration into fibrous mats, and the viability and ECM production of both EC and SMC. The layered fibrous mats with loaded EC and SMC were wrapped into a cylinder, and engineered vessels were obtained with compact EC and SMC layers after co-culture for 3 months. Randomly oriented ECM productions of EC formed a continuous endothelium covering the entire lumenal surface, and a high alignment of ECM was shown in the circumferential direction of SMC layers. The tensile strength, strain at failure and suture retention strength were higher than those of the human femoral artery, and the burst pressure and radial compliance were in the same range as the human saphenous vein, indicating potential as blood vessel substitutes for transplantation in vivo. Thus, the establishment of topographical cues and biochemical signals in fibrous scaffolds demonstrates advantages in modulating cellular behavior and organization found in complex multicellular tissues.

  20. Engineering blood vessels through micropatterned co-culture of vascular endothelial and smooth muscle cells on bilayered electrospun fibrous mats with pDNA inoculation.

    PubMed

    Liu, Yaowen; Lu, Jinfu; Li, Huinan; Wei, Jiaojun; Li, Xiaohong

    2015-01-01

    Although engineered blood vessels have seen important advances during recent years, proper mechanical strength and vasoactivity remain unsolved problems. In the current study, micropatterned fibrous mats were created to load smooth muscle cells (SMC), and a co-culture with endothelial cells (EC) was established through overlaying on an EC-loaded flat fibrous mat to mimic the layered structure of a blood vessel. A preferential distribution of SMC was determined in the patterned regions throughout the fibrous scaffolds, and aligned fibers in the patterned regions provided topological cues to guide the orientation of SMC with intense actin filaments and extracellular matrix (ECM) production in a circumferential direction. Plasmid DNA encoding basic fibroblast growth factors and vascular endothelial growth factor were integrated into electrospun fibers as biological cues to promote SMC infiltration into fibrous mats, and the viability and ECM production of both EC and SMC. The layered fibrous mats with loaded EC and SMC were wrapped into a cylinder, and engineered vessels were obtained with compact EC and SMC layers after co-culture for 3 months. Randomly oriented ECM productions of EC formed a continuous endothelium covering the entire lumenal surface, and a high alignment of ECM was shown in the circumferential direction of SMC layers. The tensile strength, strain at failure and suture retention strength were higher than those of the human femoral artery, and the burst pressure and radial compliance were in the same range as the human saphenous vein, indicating potential as blood vessel substitutes for transplantation in vivo. Thus, the establishment of topographical cues and biochemical signals in fibrous scaffolds demonstrates advantages in modulating cellular behavior and organization found in complex multicellular tissues. PMID:25305234

  1. Tumor-Triggered Controlled Drug Release from Electrospun Fibers Using Inorganic Caps for Inhibiting Cancer Relapse.

    PubMed

    Zhao, Xin; Yuan, Ziming; Yildirimer, Lara; Zhao, Jingwen; Lin, Zhi Yuan William; Cao, Zhi; Pan, Guoqing; Cui, Wenguo

    2015-09-01

    A smart, tumor-trigged, controlled drug release using inorganic "caps" with CO3 (2-) functional groups in electrospun fibers is presented for inhibiting cancer relapse. When the drug-loaded intelligent electrospun fibers encounter pathological acidic environments, the inorganic gates react with the acids and produce CO2 gas, which enables water penetration into the core of the fibers to induce rapid drug release.

  2. Varying the diameter of aligned electrospun fibers alters neurite outgrowth and Schwann cell migration.

    PubMed

    Wang, Han Bing; Mullins, Michael E; Cregg, Jared M; McCarthy, Connor W; Gilbert, Ryan J

    2010-08-01

    Aligned, electrospun fibers have shown great promise in facilitating directed neurite outgrowth within cell and animal models. While electrospun fiber diameter does influence cellular behavior, it is not known how aligned, electrospun fiber scaffolds of differing diameter influence neurite outgrowth and Schwann cell (SC) migration. Thus, the goal of this study was to first create highly aligned, electrospun fiber scaffolds of varying diameter and then assess neurite and SC behavior from dorsal root ganglia (DRG) explants. Three groups of highly aligned, electrospun poly-l-lactic acid (PLLA) fibers were created (1325+383 nm, large diameter fibers; 759+179 nm, intermediate diameter fibers; and 293+65 nm, small diameter fibers). Embryonic stage nine (E9) chick DRG were cultured on fiber substrates for 5 days and then the explants were stained against neurofilament and S100. DAPI stain was used to assess SC migration. Neurite length and SC migration distance were determined. In general, the direction of neurite extension and SC migration were guided along the aligned fibers. On the small diameter fiber substrate, the neurite length was 42% and 36% shorter than those on the intermediate and large fiber substrates, respectively. Interestingly, SC migration did not correlate with that of neurite extension in all situations. SCs migrated equivalently with extending neurites in both the small and large diameter scaffolds, but lagged behind neurites on the intermediate diameter scaffolds. Thus, in some situations, topography alone is sufficient to guide neurites without the leading support of SCs. Scanning electron microscopy images show that neurites cover the fibers and do not reside exclusively between fibers. Further, at the interface between fibers and neurites, filopodial extensions grab and attach to nearby fibers as they extend down the fiber substrate. Overall, the results and observations suggest that fiber diameter is an important parameter to consider when

  3. In vitro evaluation of electrospun chitosan mats crosslinked with genipin as guided tissue regeneration barrier membranes

    NASA Astrophysics Data System (ADS)

    Norowski, Peter Andrew, Jr.

    Guided tissue regeneration (GTR) is a surgical technique commonly used to exclude bacteria and soft tissues from bone graft sites in oral/maxillofacial bone graft sites by using a barrier membrane to maintain the graft contour and space. Current clinical barrier membrane materials based on expanded polytetrafluoroethylene (ePTFE) and bovine type 1 collagen are non-ideal and experience a number of disadvantages including membrane exposure, bacterial colonization/biofilm formation and premature degradation, all of which result in increased surgical intervention and poor bone regeneration. These materials do not actively participate in tissue regeneration, however bioactive materials, such as chitosan, may provide advantages such as the ability to stimulate wound healing and de novo bone formation. Our hypothesis is that electrospun chitosan GTR membranes will support cell attachment and growth but prevent cell infiltration/penetration of membrane, demonstrate in vitro degradation predictive of 4--6 month in vivo functionality, and will deliver antibiotics locally to prevent/inhibit periopathogenic complications. To test this hypothesis a series of chitosan membranes were electrospun, in the presence or absence of genipin, a natural crosslinking agent, at concentrations of 5 and 10 mM. These membranes were characterized by scanning electron microscopy, tensile testing, suture pullout testing, Fourier transform infrared spectroscopy, X-ray diffraction, and gel permeation chromatography, and in vitro biodegradation for diameter/morphology of fibers, membrane strengths, degree of crosslinking, crystallinity, molecular weight, and degradation kinetics, respectively. Cytocompability of membranes was evaluated in osteoblastic, fibroblastic and monocyte cultures. The activity of minocycline loaded and released from the membranes was determined in zone of inhibition tests using P. gingivalis microbe. The results demonstrated that genipin crosslinking extended the in vitro

  4. Morphology of electrospun fibers derived from High Internal Phase Emulsions.

    PubMed

    Samanta, Archana; Nandan, Bhanu; Srivastava, Rajiv K

    2016-06-01

    High Internal Phase Emulsions (HIPEs) are known for their excessive volume of dispersed phase (volume fraction of dispersed phase Φd>0.74) and are primarily used for polymerization of continuous phase monomer(s) thereby generating porous systems in a single step. In the present work, electrospinning of HIPEs formed from aqueous solution of poly(vinyl alcohol) (PVA) dispersed in continuous phase comprised of poly(ε-caprolactone) (PCL) solution in toluene is conducted. Effect of variation in volume fraction of dispersed and continuous phase on fiber morphology was studied. Fibers of co-continuous morphology were obtained due to coalescence and dielectrophoresis of the higher electrically conducting dispersed aqueous phase than toluene containing continuous phase. Removal of PVA was later done by washing of fibers with water to evaluate the presence of two phases in the fibers and relate it to original HIPE morphology of the emulsions. Heterogeneous and surface nucleation of PCL and Brij-58 confined within electrospun fibers of HIPEs was studied in detail and related to the original HIPE structure.

  5. Electrospun fiber scaffolds of poly (glycerol-dodecanedioate) and its gelatin blended polymers for soft tissue engineering.

    PubMed

    Dai, Xizi; Kathiria, Khadija; Huang, Yen-Chih

    2014-09-01

    For tissue engineering applications, biodegradable scaffolds play a vital role in supporting and guiding the seeded cells to form functional tissues by mimicking the structure and function of native extracellular matrices. Previously, we have developed a biodegradable elastomer poly (glycerol-dodecanedioate) (PGD) with mechanical properties suitable for soft tissue engineering. In the study, we found that the PGD and PGD blended with gelatin (PGD/gelatin) were able to be electrospun into fibrous scaffolds, and the diameters of the fibers could be adjusted by controlling the PGD concentration. When using our newly designed electrospinning collector, fibers could be easily harvested and the size of the fiber mat could be flexibly adjusted. The data of Raman spectra also confirmed the esterfication reaction in PGD polymerization and showed no significant structure change after electrospinning. Biocompatibility testing of the PGD and PGD/gelatin, by using human foreskin fibroblasts, indicated that gelatin could enhance cell adhesion and proliferation. Overall, electrospun fibers made from PGD and PGD/gelatin exhibited several advantages including easy synthesis from renewable raw materials, flexible fabrication by using less toxic solvents like ethanol, and good biocompatibility.

  6. Photocatalytic and antibacterial properties of a TiO2/nylon-6 electrospun nanocomposite mat containing silver nanoparticles.

    PubMed

    Pant, Hem Raj; Pandeya, Dipendra Raj; Nam, Ki Taek; Baek, Woo-Il; Hong, Seong Tshool; Kim, Hak Yong

    2011-05-15

    Silver-impregnated TiO(2)/nylon-6 nanocomposite mats exhibit excellent characteristics as a filter media with good photocatalytic and antibacterial properties and durability for repeated use. Silver nanoparticles (NPs) were successfully embedded in electrospun TiO(2)/nylon-6 composite nanofibers through the photocatalytic reduction of silver nitrate solution under UV-light irradiation. TiO(2) NPs present in nylon-6 solution were able to cause the formation of a high aspect ratio spider-wave-like structure during electrospinning and facilitated the UV photoreduction of AgNO(3) to Ag. TEM images, UV-visible and XRD spectra confirmed that monodisperse Ag NPs (approximately 4 nm in size) were deposited selectively upon the TiO(2) NPs of the prepared nanocomposite mat. The antibacterial property of a TiO(2)/nylon-6 composite mat loaded with Ag NPs was tested against Escherichia coli, and the photoactive property was tested against methylene blue. All of the results showed that TiO(2)/nylon-6 nanocomposite mats loaded with Ag NPs are more effective than composite mats without Ag NPs. The prepared material has potential as an economically friendly photocatalyst and water filter media because it allows the NPs to be reused.

  7. Characterization of carbon nanofiber mats produced from electrospun lignin-g-polyacrylonitrile copolymer.

    PubMed

    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.

  8. Characterization of carbon nanofiber mats produced from electrospun lignin-g-polyacrylonitrile copolymer.

    PubMed

    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. PMID:26459170

  9. Synthesis of titanium dioxide nanotubes from electrospun fiber templates

    NASA Astrophysics Data System (ADS)

    Qiu, Yejun; Yu, Jie

    2008-12-01

    Titanium dioxide (TiO 2) nanotubes were synthesized by impregnating stabilized electrospun polyacrylonitrile (PAN) fibers with titanium tetrachloride (TiCl 4) solution and subsequent calcination. Scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectroscopy, and energy dispersive X-ray spectroscopy (EDX) were used to characterize the structure and composition of the products. The resulting TiO 2 nanotubes are of high purity with anatase structure. The average diameter of the nanotubes is 220 nm with very thin walls about 20 nm. The tube walls are composed of many nanoparticles of about 10 nm. Due to the increased surface area and small crystal size, the present TiO 2 nanotubes may possess high catalytic properties.

  10. Electrospun fiber membranes enable proliferation of genetically modified cells

    PubMed Central

    Borjigin, Mandula; Eskridge, Chris; Niamat, Rohina; Strouse, Bryan; Bialk, Pawel; Kmiec, Eric B

    2013-01-01

    Polycaprolactone (PCL) and its blended composites (chitosan, gelatin, and lecithin) are well-established biomaterials that can enrich cell growth and enable tissue engineering. However, their application in the recovery and proliferation of genetically modified cells has not been studied. In the study reported here, we fabricated PCL-biomaterial blended fiber membranes, characterized them using physicochemical techniques, and used them as templates for the growth of genetically modified HCT116-19 colon cancer cells. Our data show that the blended polymers are highly miscible and form homogenous electrospun fiber membranes of uniform texture. The aligned PCL nanofibers support robust cell growth, yielding a 2.5-fold higher proliferation rate than cells plated on standard plastic plate surfaces. PCL-lecithin fiber membranes yielded a 2.7-fold higher rate of proliferation, while PCL-chitosan supported a more modest growth rate (1.5-fold higher). Surprisingly, PCL-gelatin did not enhance cell proliferation when compared to the rate of cell growth on plastic surfaces. PMID:23467983

  11. Aligned and Electrospun Piezoelectric Polymer Fiber Assembly and Scaffold

    NASA Technical Reports Server (NTRS)

    Scott-Carnell, Lisa A. (Inventor); Siochi, Emilie J. (Inventor); Holloway, Nancy M. (Inventor); Leong, Kam W. (Inventor); Kulangara, Karina (Inventor)

    2015-01-01

    A scaffold assembly and related methods of manufacturing and/or using the scaffold for stem cell culture and tissue engineering applications are disclosed which at least partially mimic a native biological environment by providing biochemical, topographical, mechanical and electrical cues by using an electroactive material. The assembly includes at least one layer of substantially aligned, electrospun polymer fiber having an operative connection for individual voltage application. A method of cell tissue engineering and/or stem cell differentiation uses the assembly seeded with a sample of cells suspended in cell culture media, incubates and applies voltage to one or more layers, and thus produces cells and/or a tissue construct. In another aspect, the invention provides a method of manufacturing the assembly including the steps of providing a first pre-electroded substrate surface; electrospinning a first substantially aligned polymer fiber layer onto the first surface; providing a second pre-electroded substrate surface; electrospinning a second substantially aligned polymer fiber layer onto the second surface; and, retaining together the layered surfaces with a clamp and/or an adhesive compound.

  12. Nylon 6 electrospun nanofibers mat as effective sorbent for the removal of estrogens: kinetic and thermodynamic studies

    PubMed Central

    2014-01-01

    Nylon 6 electrospun nanofibers mat was prepared via electrospinning for the removal of three estrogens, namely, diethylstilbestrol (DES), dienestrol (DS), and hexestrol (HEX) from aqueous solution. Static adsorption as well as the dynamic adsorption was evaluated by means of batch and dynamic disk flow mode, respectively. The kinetic study indicated that the adsorption of the target compounds could be well fitted by the pseudo-second-order equation, suggesting the intra-particle/membrane diffusion process as the rate-limiting step of the adsorption process. The adsorption equilibrium data were all fitted well to the Freundlich isotherm models, with a maximum adsorption capacity values in the range of 97.71 to 208.95 mg/g, which can be compared to or moderately higher than other sorbents published in the literatures. The dynamic disk mode studies indicated that the mean removal yields of three model estrogens were over 95% with a notable smaller amount of adsorbent (4 mg). Thermodynamic study revealed that the adsorption process was exothermic and spontaneous in nature. Desorption results showed that the adsorption capacity can remain up to 80% after seven times usage. It was suggested that Nylon 6 electrospun nanofibers mat has great potential as a novel effective sorbent material for estrogens removal. PMID:25114645

  13. Nylon 6 electrospun nanofibers mat as effective sorbent for the removal of estrogens: kinetic and thermodynamic studies.

    PubMed

    Qi, Fei-Fei; Cao, Yang; Wang, Min; Rong, Fei; Xu, Qian

    2014-01-01

    Nylon 6 electrospun nanofibers mat was prepared via electrospinning for the removal of three estrogens, namely, diethylstilbestrol (DES), dienestrol (DS), and hexestrol (HEX) from aqueous solution. Static adsorption as well as the dynamic adsorption was evaluated by means of batch and dynamic disk flow mode, respectively. The kinetic study indicated that the adsorption of the target compounds could be well fitted by the pseudo-second-order equation, suggesting the intra-particle/membrane diffusion process as the rate-limiting step of the adsorption process. The adsorption equilibrium data were all fitted well to the Freundlich isotherm models, with a maximum adsorption capacity values in the range of 97.71 to 208.95 mg/g, which can be compared to or moderately higher than other sorbents published in the literatures. The dynamic disk mode studies indicated that the mean removal yields of three model estrogens were over 95% with a notable smaller amount of adsorbent (4 mg). Thermodynamic study revealed that the adsorption process was exothermic and spontaneous in nature. Desorption results showed that the adsorption capacity can remain up to 80% after seven times usage. It was suggested that Nylon 6 electrospun nanofibers mat has great potential as a novel effective sorbent material for estrogens removal. PMID:25114645

  14. Nylon 6 electrospun nanofibers mat as effective sorbent for the removal of estrogens: kinetic and thermodynamic studies

    NASA Astrophysics Data System (ADS)

    Qi, Fei-Fei; Cao, Yang; Wang, Min; Rong, Fei; Xu, Qian

    2014-07-01

    Nylon 6 electrospun nanofibers mat was prepared via electrospinning for the removal of three estrogens, namely, diethylstilbestrol (DES), dienestrol (DS), and hexestrol (HEX) from aqueous solution. Static adsorption as well as the dynamic adsorption was evaluated by means of batch and dynamic disk flow mode, respectively. The kinetic study indicated that the adsorption of the target compounds could be well fitted by the pseudo-second-order equation, suggesting the intra-particle/membrane diffusion process as the rate-limiting step of the adsorption process. The adsorption equilibrium data were all fitted well to the Freundlich isotherm models, with a maximum adsorption capacity values in the range of 97.71 to 208.95 mg/g, which can be compared to or moderately higher than other sorbents published in the literatures. The dynamic disk mode studies indicated that the mean removal yields of three model estrogens were over 95% with a notable smaller amount of adsorbent (4 mg). Thermodynamic study revealed that the adsorption process was exothermic and spontaneous in nature. Desorption results showed that the adsorption capacity can remain up to 80% after seven times usage. It was suggested that Nylon 6 electrospun nanofibers mat has great potential as a novel effective sorbent material for estrogens removal.

  15. Facile and green fabrication of electrospun poly(vinyl alcohol) nanofibrous mats doped with narrowly dispersed silver nanoparticles

    PubMed Central

    Lin, Song; Wang, Run-Ze; Yi, Ying; Wang, Zheng; Hao, Li-Mei; Wu, Jin-Hui; Hu, Guo-Han; He, Hua

    2014-01-01

    Submicrometer-scale poly(vinyl alcohol) (PVA) nanofibrous mats loaded with aligned and narrowly dispersed silver nanoparticles (AgNPs) are obtained via the electrospinning process from pure water. This facile and green procedure did not need any other chemicals or organic solvents. The doped AgNPs are narrowly distributed, 4.3±0.7 nm and their contents on the nanofabric mats can be easily tuned via in situ ultraviolet light irradiation or under preheating conditions, but with different particle sizes and size distributions. The morphology, loading concentrations, and dispersities of AgNPs embedded within PVA nanofiber mats are characterized by transmission electron microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, ultraviolet-visible spectra, X-ray photoelectron spectroscopy, and X-ray diffraction, respectively. Moreover, the biocidal activities and cytotoxicity of the electrospun nanofiber mats are determined by zone of inhibition, dynamic shaking method, and cell counting kit (CCK)-8 assay tests. PMID:25170264

  16. Layer-by-layer immobilized catalase on electrospun nanofibrous mats protects against oxidative stress induced by hydrogen peroxide.

    PubMed

    Huang, Rong; Deng, Hongbing; Cai, Tongjian; Zhan, Yingfei; Wang, Xiankai; Chen, Xuanxuan; Ji, Ailing; Lil, Xueyong

    2014-07-01

    Catalase, a kind of redox enzyme and generally recognized as an efficient agent for protecting cells against hydrogen peroxide (H2O2)-induced cytotoxicity. The immobilization of catalase was accomplished by depositing the positively charged chitosan and the negatively charged catalase on electrospun cellulose nanofibrous mats through electrospining and layer-by-layer (LBL) techniques. The morphology obtained from Field emission scanning electron microscopy (FE-SEM) indicated that more orderly arranged three-dimension (3D) structure and roughness formed with increasing the number of coating bilayers. Besides, the enzyme-immobilized nanofibrous mats were found with high enzyme loading and activity, moreover, X-ray photoelectron spectroscopy (XPS) results further demonstrated the successful immobilization of chitosan and catalase on cellulose nanofibers support. Furthermore, we evaluated the cytotoxicity induced by hydrogen peroxide in the Human umbilical vascular endothelial cells with or without pretreatment of nanofibrous mats by MTT assay, LDH activity and Flow cytometric evaluation, and confirmed the pronounced hydrogen peroxide-induced toxicity, but pretreatment of immobilized catalase reduced the cytotoxicity and protected cells against hydrogen peroxide-induced cytotoxic effects which were further demonstrated by scanning electron microscopy (SEM) and Transmission Electron Microscopy (TEM) images. The data pointed toward a role of catalase-immobilized nanofibrous mats in protecting cells against hydrogen peroxide-induced cellular damage and their potential application in biomedical field.

  17. Reusable electrospun mesoporous ZnO nanofiber mats for photocatalytic degradation of polycyclic aromatic hydrocarbon dyes in wastewater.

    PubMed

    Singh, Puneet; Mondal, Kunal; Sharma, Ashutosh

    2013-03-15

    We demonstrate a new method for the fabrication of free-standing mats of mesoporous ZnO nanofibers by electrospinning a blend of zinc acetate with a carrier polymer, polyacrylonitrile (PAN) in N,N-dimethyl-formamide (DMF) solvent. Decomposition of PAN by calcination produces porous ZnO nanofibers with fiber diameters in the range of 50-150 nm depending on the electrospinning conditions such as the precursor solution concentration, electric field strength, and solution flow rate. The fibers are characterized for their morphology, phase composition, band gap, crystallinity, surface area, and porosity. In this paper, optimized mats of ZnO nanofibers with an average fiber diameter of 60 nm are shown to be highly effective in the photocatalytic degradation of the PAH dyes--naphthalene and anthracene. Nanofiber mats fabricated here may also find applications in gas sensing, piezoelectric devices, optoelectronics, and photocatalysis.

  18. The Effect of Surface Modification of Aligned Poly-L-Lactic Acid Electrospun Fibers on Fiber Degradation and Neurite Extension

    PubMed Central

    Schaub, Nicholas J.; Le Beux, Clémentine; Miao, Jianjun; Linhardt, Robert J.; Alauzun, Johan G.; Laurencin, Danielle; Gilbert, Ryan J.

    2015-01-01

    The surface of aligned, electrospun poly-L-lactic acid (PLLA) fibers was chemically modified to determine if surface chemistry and hydrophilicity could improve neurite extension from chick dorsal root ganglia. Specifically, diethylenetriamine (DTA, for amine functionalization), 2-(2-aminoethoxy)ethanol (AEO, for alcohol functionalization), or GRGDS (cell adhesion peptide) were covalently attached to the surface of electrospun fibers. Water contact angle measurements revealed that surface modification of electrospun fibers significantly improved fiber hydrophilicity compared to unmodified fibers (p < 0.05). Scanning electron microscopy (SEM) of fibers revealed that surface modification changed fiber topography modestly, with DTA modified fibers displaying the roughest surface structure. Degradation of chemically modified fibers revealed no change in fiber diameter in any group over a period of seven days. Unexpectedly, neurites from chick DRG were longest on fibers without surface modification (1651 ± 488 μm) and fibers containing GRGDS (1560 ± 107 μm). Fibers modified with oxygen plasma (1240 ± 143 μm) or DTA (1118 ± 82 μm) produced shorter neurites than the GRGDS or unmodified fibers, but were not statistically shorter than unmodified and GRGDS modified fibers. Fibers modified with AEO (844 ± 151 μm) were significantly shorter than unmodified and GRGDS modified fibers (p<0.05). Based on these results, we conclude that fiber hydrophilic enhancement alone on electrospun PLLA fibers does not enhance neurite outgrowth. Further work must be conducted to better understand why neurite extension was not improved on more hydrophilic fibers, but the results presented here do not recommend hydrophilic surface modification for the purpose of improving neurite extension unless a bioactive ligand is used. PMID:26340351

  19. The Effect of Surface Modification of Aligned Poly-L-Lactic Acid Electrospun Fibers on Fiber Degradation and Neurite Extension.

    PubMed

    Schaub, Nicholas J; Le Beux, Clémentine; Miao, Jianjun; Linhardt, Robert J; Alauzun, Johan G; Laurencin, Danielle; Gilbert, Ryan J

    2015-01-01

    The surface of aligned, electrospun poly-L-lactic acid (PLLA) fibers was chemically modified to determine if surface chemistry and hydrophilicity could improve neurite extension from chick dorsal root ganglia. Specifically, diethylenetriamine (DTA, for amine functionalization), 2-(2-aminoethoxy)ethanol (AEO, for alcohol functionalization), or GRGDS (cell adhesion peptide) were covalently attached to the surface of electrospun fibers. Water contact angle measurements revealed that surface modification of electrospun fibers significantly improved fiber hydrophilicity compared to unmodified fibers (p < 0.05). Scanning electron microscopy (SEM) of fibers revealed that surface modification changed fiber topography modestly, with DTA modified fibers displaying the roughest surface structure. Degradation of chemically modified fibers revealed no change in fiber diameter in any group over a period of seven days. Unexpectedly, neurites from chick DRG were longest on fibers without surface modification (1651 ± 488 μm) and fibers containing GRGDS (1560 ± 107 μm). Fibers modified with oxygen plasma (1240 ± 143 μm) or DTA (1118 ± 82 μm) produced shorter neurites than the GRGDS or unmodified fibers, but were not statistically shorter than unmodified and GRGDS modified fibers. Fibers modified with AEO (844 ± 151 μm) were significantly shorter than unmodified and GRGDS modified fibers (p<0.05). Based on these results, we conclude that fiber hydrophilic enhancement alone on electrospun PLLA fibers does not enhance neurite outgrowth. Further work must be conducted to better understand why neurite extension was not improved on more hydrophilic fibers, but the results presented here do not recommend hydrophilic surface modification for the purpose of improving neurite extension unless a bioactive ligand is used. PMID:26340351

  20. Nanofibrous asymmetric membranes self-organized from chemically heterogeneous electrospun mats for skin tissue engineering.

    PubMed

    Wu, Chaoxi; Chen, Tian; Xin, Yanjiao; Zhang, Zhen; Ren, Zhe; Lei, Jing; Chu, Bin; Wang, Yifei; Tang, Shunqing

    2016-01-01

    Asymmetric membranes, which mimic the structure and functions of human skin, have been extensively pursued as ideal skin tissue engineering constructs. In this study, we demonstrated that nanostructured asymmetric membranes can be prepared by the self-organization of chemically heterogeneous bilayer electrospun membranes in aqueous solutions. Structurally, the skin layer consists of hydrophobic β-glucan butyrate nanofibers and its inner layer consists of hydrophilic β-glucan acetate nanofibers. After the electrospinning process, both of the layers are in a dense state. When placed in water, the skin layer absorbs little water and still remains dense, but the fibers in the inner layer become extensively hydrated and spontaneously reorganize into a fully stretched structure, resulting in a significant volume increase and a density decrease of the inner layer. SEM imaging showed that β-glucan ester nanofibers exhibited a bead-free and uniform structure. Contact angle measurement and swelling tests showed that the inner layer was highly hydrophilic with extensive swelling, but the skin layer was highly hydrophobic with little swelling. Mechanical tests indicated that the nanofibrous asymmetric membranes had good mechanical properties in both the dry and wet states. In vitro cytocompatibility tests showed that nanofibrous asymmetric membranes could promote the adhesion and proliferation of fibroblasts and keratinocytes. A preliminary in vivo study performed on a full thickness mouse skin wound model demonstrated that the nanofibrous asymmetric membranes significantly accelerated the wound healing process by promoting re-epithelialization, tissue remodeling and collagen deposition. Taken together, our study provides a novel model for the design and fabrication of nanostructured asymmetric membranes, and our β-glucan based nanofibrous asymmetric membranes could be used as an advanced platform for skin tissue engineering. PMID:27327625

  1. Tunable engineered skin mechanics via coaxial electrospun fiber core diameter.

    PubMed

    Blackstone, Britani Nicole; Drexler, Jason William; Powell, Heather Megan

    2014-10-01

    Autologous engineered skin (ES) offers promise as a treatment for massive full thickness burns. Unfortunately, ES is orders of magnitude weaker than normal human skin causing it to be difficult to apply surgically and subject to damage by mechanical shear in the early phases of engraftment. In addition, no manufacturing strategy has been developed to tune ES biomechanics to approximate the native biomechanics at different anatomic locations. To enhance and tune ES biomechanics, a coaxial (CoA) electrospun scaffold platform was developed from polycaprolactone (PCL, core) and gelatin (shell). The ability of the coaxial fiber core diameter to control both scaffold and tissue mechanics was investigated along with the ability of the gelatin shell to facilitate cell adhesion and skin development compared to pure gelatin, pure PCL, and a gelatin-PCL blended fiber scaffold. CoA ES exhibited increased cellular adhesion and metabolism versus PCL alone or gelatin-PCL blend and promoted the development of well stratified skin with a dense dermal layer and a differentiated epidermal layer. Biomechanics of the scaffold and ES scaled linearly with core diameter suggesting that this scaffold platform could be utilized to tailor ES mechanics for their intended grafting site and reduce graft damage in vitro and in vivo.

  2. Mechanically Active Electrospun Materials

    NASA Astrophysics Data System (ADS)

    Robertson, Jaimee M.

    Electrospinning, a technique used to fabricate small diameter polymer fibers, has been employed to develop unique, active materials falling under two categories: (1) shape memory elastomeric composites (SMECs) and (2) water responsive fiber mats. (1) Previous work has characterized in detail the properties and behavior of traditional SMECs with isotropic fibers embedded in an elastomer matrix. The current work has two goals: (i) characterize laminated anisotropic SMECs and (ii) develop a fabrication process that is scalable for commercial SMEC manufacturing. The former ((i)) requires electrospinning aligned polymer fibers. The aligned fibers are similarly embedded in an elastomer matrix and stacked at various fiber orientations. The resulting laminated composite has a unique response to tensile deformation: after stretching and releasing, the composite curls. This curling response was characterized based on fiber orientation. The latter goal ((ii)) required use of a dual-electrospinning process to simultaneously electrospin two polymers. This fabrication approach incorporated only industrially relevant processing techniques, enabling the possibility of commercial application of a shape memory rubber. Furthermore, the approach had the added benefit of increased control over composition and material properties. (2) The strong elongational forces experienced by polymer chains during the electrospinning process induce molecular alignment along the length of electrospun fibers. Such orientation is maintained in the fibers as the polymer vitrifies. Consequently, residual stress is stored in electrospun fiber mats and can be recovered by heating through the polymer's glass transition temperature. Alternatively, the glass transition temperature can be depressed by introducing a plasticizing agent. Poly(vinyl acetate) (PVAc) is plasticized by water, and its glass transition temperature is lowered below room temperature. Therefore, the residual stress can be relaxed at room

  3. Fabrication of Electrospun Polymer Fibers with Nonspherical Cross-Sections Using a Nanopressing Technique.

    PubMed

    Chen, Jiun-Tai; Kao, Yi-Huei; Kuo, Tyng-Yow; Liu, Chih-Ting; Chiu, Yu-Jing; Chu, Chien-Wei; Chi, Mu-Huan; Tsai, Chia-Chan

    2016-02-01

    The fabrication of electrospun polymer fibers is demonstrated with anisotropic cross-sections by applying a simple pressing method. Electrospun polystyrene or poly(methyl methacrylate) fibers are pressed by flat or patterned substrates while the samples are annealed at elevated temperatures. The shapes and morphologies of the pressed polymer fibers are controlled by the experimental conditions such as the pressing force, the pressing temperature, the pressing time, and the surface pattern of the substrate. At the same pressing force, the shape changes of the polymer fibers can be controlled by the pressing time. For shorter pressing times, the deformation process is dominated by the effect of pressing and fibers with barrel-shaped cross-sections can be generated. For longer pressing times, the effect of wetting becomes more important and fibers with dumbbell-shaped cross-sections can be obtained. Hierarchical polymer fibers with nanorods are fabricated by pressing the fibers with porous anodic aluminum oxide templates. PMID:26574243

  4. Sulfonic Acid- and Lithium Sulfonate-Grafted Poly(Vinylidene Fluoride) Electrospun Mats As Ionic Liquid Host for Electrochromic Device and Lithium-Ion Battery.

    PubMed

    Zhou, Rui; Liu, Wanshuang; Leong, Yew Wei; Xu, Jianwei; Lu, Xuehong

    2015-08-01

    Electrospun polymer nanofibrous mats loaded with ionic liquids (ILs) are promising nonvolatile electrolytes with high ionic conductivity. The large cations of ILs are, however, difficult to diffuse into solid electrodes, making them unappealing for application in some electrochemical devices. To address this issue, a new strategy is used to introduce proton conduction into an IL-based electrolyte. Poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP)) copolymer is functionalized with sulfonic acid through covalent attachment of taurine. The sulfonic acid-grafted P(VDF-HFP) electrospun mats consist of interconnected nanofibers, leading to remarkable improvement in dimensional stability of the mats. IL-based polymer electrolytes are prepared by immersing the modified mats in 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM(+)BF4(-)). It is found that the SO3(-) groups can have Lewis acid-base interactions with the cations (BMIM(+)) of IL to promote the dissociation of ILs, and provide additional proton conduction, resulting in significantly improved ionic conductivity. Using this novel electrolyte, polyaniline-based electrochromic devices show higher transmittance contrast and faster switching behavior. Furthermore, the sulfonic acid-grafted P(VDF-HFP) electrospun mats can also be lithiated, giving additional lithium ion conduction for the IL-based electrolyte, with which Li/LiCoO2 batteries display enhanced C-rate performance.

  5. Coaxially electrospun fiber-based microbicides facilitate broadly tunable release of maraviroc.

    PubMed

    Ball, Cameron; Chou, Shih-Feng; Jiang, Yonghou; Woodrow, Kim A

    2016-06-01

    Electrospun fibers show potential as a topical delivery system for vaginal microbicides. Previous reports have demonstrated delivery of anti-HIV and anti-STI (sexually transmitted infection) agents from fibers formulated using hydrophilic, hydrophobic, or pH-responsive polymers that result in rapid, prolonged, or stimuli-responsive release, respectively. However, coaxial electrospun fibers have yet to be evaluated as a highly tunable microbicide delivery vehicle. In this research, we explored the opportunities and limitations of a model coaxial electrospun fiber system to provide broad and tunable release rates for the HIV entry inhibitor maraviroc. Specifically, we prepared ethyl cellulose (EC)-shell and polyvinylpyrrolidone (PVP)-core fibers that were capable of releasing actives over a range of hours to several days. We further demonstrated simple and effective methods for combining core-shell fibers with rapid-release formulations to provide combined instantaneous and sustained maraviroc release. In addition, we investigated the effect of varying release media on maraviroc release from core-shell fibers, and found that release was strongly influenced by media surface tension and drug ionization. Finally, in vitro cell culture studies show that our fiber formulations were not cytotoxic and that electrospun maraviroc maintained similar antiviral activity compared to neat maraviroc. PMID:27040202

  6. Properties of electrospun pollock gelatin/poly(vinyl alcohol) and pollock gelatin/poly(lactic acid) fibers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pollock gelatin/poly(vinyl alcohol) (PVA) fibers were electrospun using deionized water as the solvent and pollock gelatin/poly(lactic acid) (PLA) fibers were electrospun using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as the solvent. The chemical, thermal, and thermal stability properties were exami...

  7. Structure and properties of electrospun polymer fibers and applications in biomedical engineering

    NASA Astrophysics Data System (ADS)

    Casper, Cheryl L.

    2006-04-01

    Increased interest in nanotechnology has revived a fiber processing technique invented back in the 1930's. Electrospinning produces nanometer to micron size fibers that are not otherwise achievable using conventional fiber spinning methods. Due to small fiber diameters, high surface area, tailorable surface morphology, and the creation of an interconnected fibrous network, electrospun fibers have found use in a variety of applications. However, a multitude of parameters directly affect the electrospinning process thus requiring a fundamental understanding of how various parameters affect the process and resulting fiber properties. Accordingly, the focus of this dissertation is to provide insight on how solution characteristics and processing parameters directly affect the electrospinning process, and then apply this knowledge to create electrospun membranes for biomedical applications. These fundamental studies provided insight on how to control the electrospinning process; this knowledge was then utilized to electrospin fibrous membranes for biomedical applications. One aspect of this work focused on incorporating low molecular weight heparin (LMWH) into electrospun fibers. Heparin is known for its ability to bind growth factors and thus it plays an integral role in drug delivery and tissue engineering applications. The goal of this work was to fabricate functionalized electrospun fibers to produce a biologically active matrix that would allow for the binding and delivery of growth factors for possible drug delivery applications. The electrospinning process was also utilized to fabricate native polymers such as collagen and gelatin into fiber form. The collagen and gelatin fibers were 2--6 mum in diameter and required crosslinking to stabilize the fibers. Crosslinking and sterilization protocols were investigated to optimize the conditions needed to produce collagen and gelatin electrospun membranes to be used in bone regeneration applications. (Abstract shortened

  8. Electrospun Poly(L-Lactide) Fiber with Ginsenoside Rg3 for Inhibiting Scar Hyperplasia of Skin

    PubMed Central

    Hu, Changmin; Li, Haiyan; Zhang, Yuguang; Chang, Jiang

    2013-01-01

    Hypertrophic scarring (HS) has been considered as a great concern for patients and a challenging problem for clinicians as it can be cosmetically disfiguring and functionally debilitating. In this study, Ginsenoside Rg3/Poly(l-lactide) (G-Rg3/PLLA) electrospun fibrous scaffolds covering on the full-thickness skin excisions location was designed to suppress the hypertrophic scar formation in vivo. SEM and XRD results indicated that the crystal G-Rg3 carried in PLLA electrospun fibers was in amorphous state, which facilitates the solubility of G-Rg3 in the PLLA electrospun fibrous scaffolds, and solubility of G-Rg3 in PBS is increased from 3.2 µg/ml for pure G-Rg3 powders to 19.4 µg/ml for incorporated in PLLA-10% fibers. The released G-Rg3 content in the physiological medium could be further altered from 324 to 3445 µg in a 40-day release period by adjusting the G-Rg3 incorporation amount in PLLA electrospun fibers. In vitro results demonstrated that electrospun G-Rg3/PLLA fibrous scaffold could significantly inhibit fibroblast cell growth and proliferation. In vivo results confirmed that the G-Rg3/PLLA electrospun fibrous scaffold showed significant improvements in terms of dermis layer thickness, fibroblast proliferation, collagen fibers and microvessels, revealing that the incorporation of the G-Rg3 in the fibers prevented the HS formation. The above results demonstrate the potential use of G-Rg3/PLLA electrospun fibrous scaffolds to rapidly minimize fibroblast growth and restore the structural and functional properties of wounded skin for patients with deep trauma, severe burn injury, and surgical incision. PMID:23874757

  9. Antibacterial activity and inhibition of adherence of Streptococcus mutans by propolis electrospun fibers.

    PubMed

    Asawahame, Chawalinee; Sutjarittangtham, Krit; Eitssayeam, Sukum; Tragoolpua, Yingmanee; Sirithunyalug, Busaban; Sirithunyalug, Jakkapan

    2015-02-01

    Mouth-dissolving fibers with antibacterial activity for the oral cavity were prepared by an electrospinning technique. Propolis extract was used as an active ingredient and polyvinylpyrrolidone (PVP) K90 as the polymer matrix. The morphology and diameter of the fibers were characterized by scanning electron microscopy. Antibacterial activity against Streptococcus mutans and the inhibition of S. mutans adhesion on a smooth glass surface during the biofilm formation were tested. Propolis, 5% (w/v), was combined with a PVP K90 solution, 8% (w/v), with or without Tween 80 including flavor additives and electrospun with an applied voltage of 15 kV. Uniform and smooth fibers of propolis-PVP K90 were obtained. The results showed that electrospun fibers with propolis extract can dissolve and release the propolis in water. Propolis-PVP electrospun fibers showed better antibacterial activity by reduction of bacteria adhesion on a smooth glass surface when compared to some commercial mouthwash products. These results indicated the potential of electrospun fibers to be used as mouth-dissolving fibers for effective antibacterial activity in the oral cavity.

  10. Chitin butyrate coated electrospun nylon-6 fibers for biomedical applications

    NASA Astrophysics Data System (ADS)

    Pant, Hem Raj; Kim, Han Joo; Bhatt, Lok Ranjan; Joshi, Mahesh Kumar; Kim, Eun Kyo; Kim, Jeong In; Abdal-hay, Abdalla; Hui, K. S.; Kim, Cheol Sang

    2013-11-01

    In this study, we describe the preparation and characterizations of chitin butyrate (CB) coated nylon-6 nanofibers using single-spinneret electrospinning of blends solution. The physicochemical properties of nylon-6 composite fibers with different proportions of CB to nylon-6 were determined using FE-SEM, TEM, FT-IR spectroscopy, and water contact angle measurement. FE-SEM and TEM images revealed that the nylon-6 and CB were immiscible in the as-spun nanofibers, and phase separated nanofiber morphology becomes more pronounced with increasing amounts of CB. The bone formation ability of composite fibers was evaluated by incubating in biomimetic simulated body fluid. In order to assay the cytocompatibility and cell behavior on the composite scaffolds, osteoblast cells were seeded on the matrix. Results suggest that the deposition of CB layer on the surface of nylon-6 could increase its cell compatibility and bone formation ability. Therefore, as-synthesized nanocomposite fibrous mat has great potentiality in hard tissue engineering.

  11. Antibacterial electrospun chitosan-polyethylene oxide nanocomposite mats containing bioactive silver nanoparticles.

    PubMed

    Kohsari, Iraj; Shariatinia, Zahra; Pourmortazavi, Seied Mahdi

    2016-04-20

    The antimicrobial chitosan-polyethylene oxide (CS-PEO) nanofibrous mats were developed by electrospinning technique for wound dressing applications. Indeed, a green route was introduced for fabrication of antibacterial mats loaded with 0.25% and 0.50% (w/w) of bioactive silver nanoparticles (Ag NPs, ∼70nm diameter) reduced by Falcaria vulgaris herbal extract. The mats were characterized by FE-SEM, EDAX, elemental mapping, FT-IR, contact angle, TGA/DSC as well as tensile strength analysis. All of the nanofibers had an average ∼200nm diameter. Interestingly, both of the CS-PEO mats containing 0.25% and 0.50% bioactive F. vulgaris-Ag NPs revealed 100% bactericidal activities against both Staphylococcus aureus and Escherichia coli bacteria. The silver release from nanofiber mats was sharply increased within first eight hours for both CS-PEO mats including 0.25% and 0.50% F. vulgaris-Ag NPs but after that the Ag nanoparticles were released very slowly (almost constant). The improved hydrophilicity, higher tensile strength and much greater silver release for CS-PEO-0.50% F. vulgaris-Ag NPs relative to those of the CS-PEO 0.25% F. vulgaris-Ag NPs suggested that the former was superior for biomedical applications. PMID:26876856

  12. Understanding Polymorphism Formation in Electrospun Fibers of Immiscible Poly(vinylidene fluoride) Blends

    SciTech Connect

    G Zhong; L Zhang; R Su; K Wang; H Fong; L Zhu

    2011-12-31

    Effects of electric poling, mechanical stretching, and dipolar interaction on the formation of ferroelectric ({beta} and/or {gamma}) phases in poly(vinylidene fluoride) (PVDF) have been studied in electrospun fibers of PVDF/polyacrylonitrile (PAN) and PVDF/polysulfone (PSF) blends with PVDF as the minor component, using wide-angle X-ray diffraction and Fourier transform infrared techniques. Experimental results of as-electrospun neat PVDF fibers (beaded vs. bead-free) showed that mechanical stretching during electrospinning, rather than electric poling, was effective to induce ferroelectric phases. For as-electrospun PVDF blend fibers with the non-polar PSF matrix, mechanical stretching during electrospinning again was capable of inducing some ferroelectric phases in addition to the major paraelectric ({alpha}) phase. However, after removing the mechanical stretching in a confined melt-recrystallization process, only the paraelectric phase was obtained. For as-electrospun PVDF blend fibers with the polar (or ferroelectric) PAN matrix, strong intermolecular interactions between polar PAN and PVDF played an important role in the ferroelectric phase formation in addition to the mechanical stretching effect during electrospinning. Even after the removal of mechanical stretching through the confined melt-recrystallization process, a significant amount of ferroelectric phases persisted. Comparing the ferroelectric phase formation between PVDF/PSF and PVDF/PAN blend fibers, we concluded that the local electric field-dipole interactions were the determining factor for the nucleation and growth of polar PVDF phases.

  13. Multifunctionalized electrospun silk fibers promote axon regeneration in central nervous system

    PubMed Central

    Wittmer, Corinne R.; Claudepierre, Thomas; Reber, Michael; Wiedemann, Peter; Garlick, Jonathan A.; Kaplan, David

    2012-01-01

    The repair of central nerves remains a major challenge in regenerative neurobiology. Regenerative guides possessing critical features such as cell adhesion, physical guiding and topical stimulation are needed. To generate such a guide, silk protein materials are prepared using electrospinning. The silk is selected for this study due to its biocompatibility and ability to be electrospun for the formation of aligned biofunctional nanofibers. The addition of Brain Derived Neurotrophic Factor (BDNF), Ciliary Neurotrophic Factor (CNTF) or both to the electrospun fibers enable enhanced function without impact to the structure or the surface morphology. Only a small fraction of the loaded growth factors is released over time allowing the fibers to continue to provide these factors to the cells for extended periods of time. The entrapped factors remain active and available to the cells as rat retinal ganglion cells (RGCs) exhibit longer axonal growth when in contact with the biofunctionalized fibers. Compare to non-functionalized fibers, the growth of neurites increased 2 fold on fibers containing BDNF, 2.5 fold with fibers containing CNTF and by almost 3-fold on fibers containing both factors. The results demonstrate the potential of aligned and functionalized electrospun silk fibers to promote nerve growth in the central nervous system, underlying the great potential of complex biomaterials in neuroregenerative strategies following axotomy and nerve crush traumas. PMID:22844266

  14. Can natural fibers be a silver bullet? Antibacterial cellulose fibers through the covalent bonding of silver nanoparticles to electrospun fibers.

    PubMed

    Zheng, Yingying; Cai, Chao; Zhang, Fuming; Monty, Jonathan; Linhardt, Robert J; Simmons, Trevor J

    2016-02-01

    Natural cotton was dissolved in a room-temperature ionic liquid 1-ethyl-3-methyl acetate and wet-jet electrospun to obtain nanoscale cotton fibers with a substantially reduced diameter-and therefore an increased surface area-relative to natural cotton fibers. The resulting nano-cotton fibers were esterified with trityl-3-mercaptopropionic acid, which after selective de-tritylation afforded nano-cotton fibers containing reactive thiol functionality. Silver nanoparticles that were covalently attached to these sulfhydryl groups were assembled next. The microstructure of the resulting nanocomposite was characterized, and the antibacterial activity of the resulting nano-cotton Ag-nanoparticle composite was also studied. This nanocomposite showed significant activity against both Gram-negative and Gram-positive bacteria. PMID:26751520

  15. Can natural fibers be a silver bullet? Antibacterial cellulose fibers through the covalent bonding of silver nanoparticles to electrospun fibers

    NASA Astrophysics Data System (ADS)

    Zheng, Yingying; Cai, Chao; Zhang, Fuming; Monty, Jonathan; Linhardt, Robert J.; Simmons, Trevor J.

    2016-02-01

    Natural cotton was dissolved in a room-temperature ionic liquid 1-ethyl-3-methyl acetate and wet-jet electrospun to obtain nanoscale cotton fibers with a substantially reduced diameter—and therefore an increased surface area—relative to natural cotton fibers. The resulting nano-cotton fibers were esterified with trityl-3-mercaptopropionic acid, which after selective de-tritylation afforded nano-cotton fibers containing reactive thiol functionality. Silver nanoparticles that were covalently attached to these sulfhydryl groups were assembled next. The microstructure of the resulting nanocomposite was characterized, and the antibacterial activity of the resulting nano-cotton Ag-nanoparticle composite was also studied. This nanocomposite showed significant activity against both Gram-negative and Gram-positive bacteria.

  16. Effect of silver nanoparticles and cellulose nanocrystals on electrospun poly(lactic) acid mats: morphology, thermal properties and mechanical behavior.

    PubMed

    Cacciotti, Ilaria; Fortunati, Elena; Puglia, Debora; Kenny, Josè Maria; Nanni, Francesca

    2014-03-15

    The fabrication of ternary fibrous mats based on poly(lactic) acid (PLA), cellulose nanocrystals (CNCs, both pristine (p-CNCs) and modified with a commercial surfactant (s-CNCs)) and silver (Ag) nanoparticles by electrospinning is reported. Amounts of 1 and 5 wt.% were selected for Ag and CNCs, respectively. Neat PLA and binary PLA/Ag, PLA/p-CNCs and PLA/s-CNCs were produced as references. The CNCs and Ag influence on the microstructural, thermal and mechanical properties was investigated. The Ag and/or p-CNCs addition did not remarkably affect fiber morphology and average size dimension (between (468 ± 111) and (551 ± 122)nm), whereas the s-CNCs presence led to the deposition of a honeycomb-like network on a underneath layer of randomly oriented fibers. The efficiency of the surfactant use in promoting the CNC dispersion was demonstrated. A slight enhancement (e.g. around 25%, in terms of strength) of the mechanical properties of p-CNCs loaded fibers, particularly for PLA/Ag/p-CNCs, was revealed, whereas mats with s-CNCs showed a decrement (e.g. around 35-45%, in terms of strength), mainly imputable to the delamination between the upper honeycomb-like layer and the lower conventional fibrous mat. PMID:24528696

  17. Electric Field Effects on Fiber Alignment Using an Auxiliary Electrode During Electrospinning

    NASA Technical Reports Server (NTRS)

    Carnell, Lisa S.; Siochi, Emilie J.; Wincheski, Russell A.; Holloway, Nancy M.; Clark, Robert L.

    2009-01-01

    Control of electrospun fiber placement and distribution was investigated by examining the effect of electric field parameters on the electrospinning of fibers. The experimental set-up used in this study eliminated the bending instability and whipping, allowing the jet to be modeled as a stable trajectory. Coupling of experimental and computational results suggests the potential for predicting aligned fiber distribution in electrospun mats.

  18. Enhanced Power Output of a Triboelectric Nanogenerator Composed of Electrospun Nanofiber Mats Doped with Graphene Oxide

    PubMed Central

    Huang, Tao; Lu, Mingxia; Yu, Hao; Zhang, Qinghong; Wang, Hongzhi; Zhu, Meifang

    2015-01-01

    We developed a book-shaped triboelectric nanogenerator (TENG) that consists of electrospun polyvinylidene fluoride (PVDF) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofibers to effectively harvest mechanical energy. The dispersed graphene oxide in the PVDF nanofibers acts as charge trapping sites, which increased the interface for charge storage as well as the output performance of the TENG. The book-shaped TENG was used as a direct power source to drive small electronics such as LED bulbs. This study proved that it is possible to improve the performance of TENGs using composite materials. PMID:26387825

  19. Enhanced Power Output of a Triboelectric Nanogenerator Composed of Electrospun Nanofiber Mats Doped with Graphene Oxide

    NASA Astrophysics Data System (ADS)

    Huang, Tao; Lu, Mingxia; Yu, Hao; Zhang, Qinghong; Wang, Hongzhi; Zhu, Meifang

    2015-09-01

    We developed a book-shaped triboelectric nanogenerator (TENG) that consists of electrospun polyvinylidene fluoride (PVDF) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofibers to effectively harvest mechanical energy. The dispersed graphene oxide in the PVDF nanofibers acts as charge trapping sites, which increased the interface for charge storage as well as the output performance of the TENG. The book-shaped TENG was used as a direct power source to drive small electronics such as LED bulbs. This study proved that it is possible to improve the performance of TENGs using composite materials.

  20. Electrospun fiber and cast films produced using zein blends with nylon-6

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Blends of zein and nylon-6 (55k) were used to produce electrospun fibers and solution cast films. Zein was blended with nylon-6 in formic acid solution. When the amount of nylon-6 was 8% or less a compatible blend formed. The blend was determined to be compatible based on physical property measureme...

  1. Experimental development of advanced air filtration media based on electrospun polymer fibers

    NASA Astrophysics Data System (ADS)

    Ghochaghi, Negar

    Electrospinning is a process by which polymer fibers can be produced using an electrostatically driven fluid jet. Electrospun fibers can be produced at the micro- or nano-scale and are, therefore, very promising for air filtration applications. However, because electrospun fibers are electrically charged, it is difficult to control the morphology of filtration media. Fiber size, alignment and uniformity are very important factors that affect filter performance. The focus of this project is to understand the relationship between filter morphology and performance and to develop new methods to create filtration media with optimum morphology. This study is divided into three focus areas: unimodal and bimodal microscale fibrous media with aligned, orthogonal and random fiber orientations; unimodal and bimodal nanoscale fibers in random orientations; bimodal micrometer and nanometer fiber media with orthogonally aligned orientations. The results indicate that the most efficient filters, which are those with the highest ratio of particle collection efficiency divided by pressure drop, can be obtained through fabricating filters in orthogonal layers of aligned fibers with two different fiber diameters. Moreover, our results show that increasing the number of layers increases the performance of orthogonally layered fibers. Also, controlling fiber spacing in orthogonally layered micrometer fiber media can be an alternative way to study the filtration performance. Finally, such coatings presented throughout this research study can be designed and placed up-stream, down-stream, and/or in between conventional filters.

  2. Super-Hydrophobic High Throughput Electrospun Cellulose Acetate (CA) Nanofibrous Mats as Oil Selective Sorbents

    NASA Astrophysics Data System (ADS)

    Han, Chao

    The threat of oil pollution increases with the expansion of oil exploration and production activities, as well as the industrial growth around the world. Use of sorbents is a common method to deal with the oil spills. In this work, an advanced sorbent technology is described. A series of non-woven Cellulose Acetate (CA) nanofibrous mats with a 3D fibrous structure were synthesized by a novel high-throughput electrospinning technique. The precursor was solutions of CA/ acetic acid-acetone in various concentrations. Among them, 15.0% CA exhibits a superhydrophobic surface property, with a water contact angle of 128.95°. Its oil sorption capacity is many times higher the oil sorption capacity of the best commercial sorbent available in the market. Also, it showed good buoyancy properties on the water both as dry-mat and oil-saturated mat. In addition, it is biodegradable, easily available, easily manufactured, so the CA nanofibrous mat is an excellent candidate as oil sorbent for oil spill in water treatment.

  3. Synchrotron X-ray Scattering Studies of Poly(lactide) Electrospun Fibers Containing Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Zhu, Yazhe; Cebe, Peggy

    2014-03-01

    Carbon nanotubes(CNTs) often serve as an effective nucleating agent that facilitates the crystallization of semicrystalline polymers. Here we study the influence of CNTs on thermal and structural properties of Poly-lactide (PLA), which is well-known as a biodegradable and biocompatible thermoplastic polymer. The effect of CNTs on the crystallization and melting behavior of electrospun fibers of poly (L-lactide) (PLLA, with 100% L-isomer) and poly (D-lactide) (PDLA, containing 4% D-isomer) was systemically studied by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), Fourier transform spectroscopy(FT-IR) and real time synchrotron wide-angle X-ray scattering (WAXS) . Multi-walled CNTs were co-electrospun with the poly(lactides) in weight ratios ranging from 0.1 to 4.0 wt% MW-CNT. PLA/carbon nanotubes composite electrospun fibers were successfully produced by appropriate choice of processing conditions and solution concentration. The morphologies of neat and CNT-filled electrospun nanofibers were observed by scanning electron microscopy. WAXS and DSC results show that lower content of CNTs contributes to higher speed of crystallization. However the results also showed that at the highest concentration of CNTs the ultimate crystallinity was reduced. FTIR and X-ray results show that PLA fibers have different crystal forms at high and low crystallization temperature. DSC results also show that D-lactide has reduced crystallinity compared to L-lactide.

  4. Flexible and Stretchable Piezoelectric Sensor with Thickness-Tunable Configuration of Electrospun Nanofiber Mat and Elastomeric Substrates.

    PubMed

    Park, Suk-Hee; Lee, Han Bit; Yeon, Si Mo; Park, Jeanho; Lee, Nak Kyu

    2016-09-21

    Here, we developed highly sensitive piezoelectric sensors in which flexible membrane components were harmoniously integrated. An electrospun nanofiber mat of poly(vinylidenefluoride-co-trifluoroethylene) was sandwiched between two elastomer sheets with sputtered electrodes as an active layer for piezoelectricity. The developed sensory system was ultrasensitive in response to various microscale mechanical stimuli and able to perceive the corresponding deformation at a resolution of 1 μm. Owing to the highly flexible and resilient properties of the components, the durability of the device was sufficiently stable so that the measuring performance could still be effective under harsh conditions of repetitive stretching and folding. When employing spin-coated thin elastomer films, the thickness of the entire sandwich architecture could be less than 100 μm, thereby achieving sufficient compliance of mechanical deformation to accommodate artery-skin motion of the heart pulse. These skin-attachable film- or sheet-type mechanical sensors with high flexibility are expected to enable various applications in the field of wearable devices, medical monitoring systems, and electronic skin. PMID:27571166

  5. Flexible and Stretchable Piezoelectric Sensor with Thickness-Tunable Configuration of Electrospun Nanofiber Mat and Elastomeric Substrates.

    PubMed

    Park, Suk-Hee; Lee, Han Bit; Yeon, Si Mo; Park, Jeanho; Lee, Nak Kyu

    2016-09-21

    Here, we developed highly sensitive piezoelectric sensors in which flexible membrane components were harmoniously integrated. An electrospun nanofiber mat of poly(vinylidenefluoride-co-trifluoroethylene) was sandwiched between two elastomer sheets with sputtered electrodes as an active layer for piezoelectricity. The developed sensory system was ultrasensitive in response to various microscale mechanical stimuli and able to perceive the corresponding deformation at a resolution of 1 μm. Owing to the highly flexible and resilient properties of the components, the durability of the device was sufficiently stable so that the measuring performance could still be effective under harsh conditions of repetitive stretching and folding. When employing spin-coated thin elastomer films, the thickness of the entire sandwich architecture could be less than 100 μm, thereby achieving sufficient compliance of mechanical deformation to accommodate artery-skin motion of the heart pulse. These skin-attachable film- or sheet-type mechanical sensors with high flexibility are expected to enable various applications in the field of wearable devices, medical monitoring systems, and electronic skin.

  6. Functionality in Electrospun Nanofibrous Membranes Based on Fiber's Size, Surface Area, and Molecular Orientation

    PubMed Central

    Matsumoto, Hidetoshi; Tanioka, Akihiko

    2011-01-01

    Electrospinning is a versatile method for forming continuous thin fibers based on an electrohydrodynamic process. This method has the following advantages: (i) the ability to produce thin fibers with diameters in the micrometer and nanometer ranges; (ii) one-step forming of the two- or three-dimensional nanofiber network assemblies (nanofibrous membranes); and (iii) applicability for a broad spectrum of molecules, such as synthetic and biological polymers and polymerless sol-gel systems. Electrospun nanofibrous membranes have received significant attention in terms of their practical applications. The major advantages of nanofibers or nanofibrous membranes are the functionalities based on their nanoscaled-size, highly specific surface area, and highly molecular orientation. These functionalities of the nanofibrous membranes can be controlled by their fiber diameter, surface chemistry and topology, and internal structure of the nanofibers. This report focuses on our studies and describes fundamental aspects and applications of electrospun nanofibrous membranes. PMID:24957735

  7. Overcoming drug crystallization in electrospun fibers--Elucidating key parameters and developing strategies for drug delivery.

    PubMed

    Seif, Salem; Franzen, Lutz; Windbergs, Maike

    2015-01-15

    For the development of novel therapeutics, uncontrolled crystallization of drugs within delivery systems represents a major challenge. Especially for thin and flexible polymeric systems such as oral films or dermal wound dressings, the formation and growth of drug crystals can significantly affect drug distribution and release kinetics as well as physical storage stability. In this context, electrospinning was introduced as a fabrication technique with the potential to encapsulate drugs within ultrafine fibers by rapid solvent evaporation overcoming drug crystallization during fabrication and storage. However, these effects could so far only be shown for specific drug-polymer combinations and an in-depth understanding of the underlying processes of drug-loaded fiber formation and influencing key parameters is still missing. In this study, we systematically investigated crystal formation of caffeine as a model drug in electrospun fibers comparing different polymers. The solvent polarity was found to have a major impact on the drug crystal formation, whereas only a minor effect was attributed to the electrospinning process parameters. Based on an in-depth understanding of the underlying processes determining drug crystallization processes in electrospun fibers, key parameters could be identified which allow for the rational development of drug-loaded electrospun fibers overcoming drug crystallization.

  8. Electrospun Synthetic Polypeptide Nanofibrous Biomaterials

    NASA Astrophysics Data System (ADS)

    Khadka, Dhan; Haynie, Donald

    2011-03-01

    Water-insoluble nanofiber mats of synthetic polypeptides of defined composition have been prepared from fibers electrospun from aqueous solution in the absence of organic co-solvents. 20-50 kDa poly(L-glutamate, L-tyrosine) 4:1 (PLGY) but not 15-50 kDa or 50-100 kDa poly(L-glutamate) was spinnable at 20-55% (w/v) polymer in water. Applied voltage and needle-collector distance were crucial for spinnability. Attractive fibers were obtained at 50% polymer. Fiber diameter and mat morphology have been characterized by electron microscopy. Exposure of spun fiber mats to 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC), which reacts with carboxylate, decreased fiber solubility. Fluorescein-conjugated poly(L-lysine) (FITC-PLL) but not the fluorophore alone was able bind PLGY fiber mats electrostatically, judging by fluorescence microscopy. Key advances of this work are the avoidance of an animal source of peptides and of an inorganic co-solvent to achieve polypeptide spinnability. Polypeptide fiber mats are a promising type of nano-structured biomaterial for applications in biomedicine and biotechnology.

  9. Electrospun Ultrafine Fiber Composites Containing Fumed Silica: From Solution Rheology to Materials with Tunable Wetting.

    PubMed

    Dufficy, Martin K; Geiger, Mackenzie T; Bonino, Christopher A; Khan, Saad A

    2015-11-17

    Fumed silica (FS) particles with hydrophobic (R805) or hydrophilic (A150) surface functionalities are incorporated in polyacrylonitrile (PAN) fibers by electrospinning to produce mats with controlled wettability. Rheological measurements are conducted to elucidate the particle-polymer interactions and characterize the system while microscopic and analytic tools are used to examine FS location within both fibers and films to aid in the fundamental understanding of wetting behavior. Unlike traditional polymers, we find these systems to be gel-like, yet electrospinnable; the fumed silica networks break down into smaller aggregates during the electrospinning process and disperse both within and on the surface of the fibers. Composite nanofiber mats containing R805 FS exhibit an apparent contact angle over 130° and remain hydrophobic over 30 min, while similar mats with A150 display rapid surface-wetting with a static contact angle of ∼30°. Wicking experiments reveal that the water absorption properties can be further manipulated, with R805 FS-impregnated mats taking up only 8% water relative to mat weight in 15 min. In contrast, PAN fibers containing A150 FS absorb 425% of water in the same period, even more than the pure PAN fiber (371%). The vastly different responses to water demonstrate the versatility of FS in surface modification, especially for submicron fibrous mats. The role of fumed silica in controlling wettability is discussed in terms of their surface functionality, placement on nanofibers and induced surface roughness. PMID:26477547

  10. Electrospun Ultrafine Fiber Composites Containing Fumed Silica: From Solution Rheology to Materials with Tunable Wetting.

    PubMed

    Dufficy, Martin K; Geiger, Mackenzie T; Bonino, Christopher A; Khan, Saad A

    2015-11-17

    Fumed silica (FS) particles with hydrophobic (R805) or hydrophilic (A150) surface functionalities are incorporated in polyacrylonitrile (PAN) fibers by electrospinning to produce mats with controlled wettability. Rheological measurements are conducted to elucidate the particle-polymer interactions and characterize the system while microscopic and analytic tools are used to examine FS location within both fibers and films to aid in the fundamental understanding of wetting behavior. Unlike traditional polymers, we find these systems to be gel-like, yet electrospinnable; the fumed silica networks break down into smaller aggregates during the electrospinning process and disperse both within and on the surface of the fibers. Composite nanofiber mats containing R805 FS exhibit an apparent contact angle over 130° and remain hydrophobic over 30 min, while similar mats with A150 display rapid surface-wetting with a static contact angle of ∼30°. Wicking experiments reveal that the water absorption properties can be further manipulated, with R805 FS-impregnated mats taking up only 8% water relative to mat weight in 15 min. In contrast, PAN fibers containing A150 FS absorb 425% of water in the same period, even more than the pure PAN fiber (371%). The vastly different responses to water demonstrate the versatility of FS in surface modification, especially for submicron fibrous mats. The role of fumed silica in controlling wettability is discussed in terms of their surface functionality, placement on nanofibers and induced surface roughness.

  11. Electrospun titania-based fibers for high areal capacity Li-ion battery anodes

    NASA Astrophysics Data System (ADS)

    Self, Ethan C.; Wycisk, Ryszard; Pintauro, Peter N.

    2015-05-01

    Electrospinning is utilized to prepare composite fiber Li-ion battery anodes containing titania and carbon nanoparticles with a poly (acrylic acid) binder. The electrospun material exhibits a stable charge/discharge capacity with only 5% capacity fade over 450 cycles at 0.5 C. Compared to a conventional slurry cast electrode of the same composition, the electrospun anode demonstrates 4-fold higher capacity retention (31% vs. 7.9%) at a charge/discharge rate of 5 C. Electrospinning is also used to prepare ultrathick anodes (>1 mm) with areal capacities up to 3.9 mAh cm-2. Notably, the thick electrodes exhibit areal capacities of 2.5 and 1.3 mAh cm-2 at 1 C and 2 C, respectively. Electrospun anodes with densely packed fibers have a 2 C volumetric capacity which exceeds that of the slurry cast material (21.2 and 17.5 mAh cm-3, respectively). The excellent performance of the electrospun anodes is attributed to interfiber voids which provide complete electrolyte intrusion, a large electrode/electrolyte interface, and short Li+ transport pathways between the electrolyte and titania nanoparticles.

  12. Shape Memory Composites Based on Electrospun Poly(vinyl alcohol) Fibers and a Thermoplastic Polyether Block Amide Elastomer.

    PubMed

    Shirole, Anuja; Sapkota, Janak; Foster, E Johan; Weder, Christoph

    2016-03-01

    The present study aimed at developing new thermally responsive shape-memory composites, that were fabricated by compacting mats of electrospun poly(vinyl alcohol) (PVA) fibers and sheets of a thermoplastic polyether block amide elastomer (PEBA). This design was based on the expectation that the combination of the rubber elasticity of the PEBA matrix and the mechanical switching exploitable through the reversible glass transition temperature (Tg) of the PVA filler could be combined to create materials that display shape memory characteristics as an emergent effect. Dynamic mechanical analyses (DMA) show that, upon introduction of 10-20% w/w PVA fibers, the room-temperature storage modulus (E') increased by a factor of 4-5 in comparison to the neat PEBA, and they reveal a stepwise reduction of E' around the Tg of PVA (85 °C). This transition could indeed be utilized to fix a temporary shape and recover the permanent shape. At low strain, the fixity was 66 ± 14% and the recovery was 98 ± 2%. Overall, the data validate a simple and practical strategy for the fabrication of shape memory composites that involves a melt compaction process and employs two commercially available polymers. PMID:26900879

  13. Shape Memory Composites Based on Electrospun Poly(vinyl alcohol) Fibers and a Thermoplastic Polyether Block Amide Elastomer.

    PubMed

    Shirole, Anuja; Sapkota, Janak; Foster, E Johan; Weder, Christoph

    2016-03-01

    The present study aimed at developing new thermally responsive shape-memory composites, that were fabricated by compacting mats of electrospun poly(vinyl alcohol) (PVA) fibers and sheets of a thermoplastic polyether block amide elastomer (PEBA). This design was based on the expectation that the combination of the rubber elasticity of the PEBA matrix and the mechanical switching exploitable through the reversible glass transition temperature (Tg) of the PVA filler could be combined to create materials that display shape memory characteristics as an emergent effect. Dynamic mechanical analyses (DMA) show that, upon introduction of 10-20% w/w PVA fibers, the room-temperature storage modulus (E') increased by a factor of 4-5 in comparison to the neat PEBA, and they reveal a stepwise reduction of E' around the Tg of PVA (85 °C). This transition could indeed be utilized to fix a temporary shape and recover the permanent shape. At low strain, the fixity was 66 ± 14% and the recovery was 98 ± 2%. Overall, the data validate a simple and practical strategy for the fabrication of shape memory composites that involves a melt compaction process and employs two commercially available polymers.

  14. Electrospun antimicrobial hybrid mats: Innovative packaging material for meat and meat-products.

    PubMed

    Amna, Touseef; Yang, Jieun; Ryu, Kyeong-Seon; Hwang, I H

    2015-07-01

    To prevent the development and spread of spoilage/pathogenic microorganisms via meat foodstuffs, antimicrobial nanocomposite packaging can serve as a potential alternative. The objective of this study was to develop a new class of antimicrobial hybrid packaging mat composed of biodegradable polyurethane supplemented with virgin olive oil and zinc oxide via electrospinning. Instead of mixing antimicrobial compounds directly with food, incorporation in packaging materials allows the functional effect at food surfaces where microbial activity is localized. The nanofibers were characterized by SEM, EDX, XRD and TEM. The antibacterial activity was tested against two common foodborne pathogens viz., Staphylococcus aureus and Salmonella typhimurium. The present results indicated that incorporation of olive oil in the polymer affected morphology of PU nanofibers and nanocomposite packaging were able to inhibit growth of pathogens. Thus; as-spun mat can be used as prospective antimicrobial packaging, which potentially reduces contamination of meat/meat-products. Moreover, introduced biodegradable packaging for meat products could serve to replace PVC films and simultaneously help to protect natural environment.

  15. Polymethacrylate coated electrospun PHB fibers: An exquisite outlook for fabrication of paper-based biosensors.

    PubMed

    Hosseini, Samira; Azari, Pedram; Farahmand, Elham; Gan, S N; Rothan, Hussin A; Yusof, Rohana; Koole, Leo H; Djordjevic, Ivan; Ibrahim, Fatimah

    2015-07-15

    Electrospun polyhydroxybutyrate (PHB) fibers were dip-coated by polymethyl methacrylate-co-methacrylic acid, poly(MMA-co-MAA), which was synthesized in different molar ratios of the monomers via free-radical polymerization. Fabricated platfrom was employed for immobilization of the dengue antibody and subsequent detection of dengue enveloped virus in enzyme-linked immunosorbent assay (ELISA). There is a major advantage for combination of electrospun fibers and copolymers. Fiber structre of electrospun PHB provides large specific surface area available for biomolecular interaction. In addition, polymer coated parts of the platform inherited the premanent presence of surface carboxyl (-COOH) groups from MAA segments of the copolymer which can be effectively used for covalent and physical protein immobilization. By tuning the concentration of MAA monomers in polymerization reaction the concentration of surface -COOH groups can be carefully controlled. Therefore two different techniques have been used for immobilization of the dengue antibody aimed for dengue detection: physical attachment of dengue antibodies to the surface and covalent immobilization of antibodies through carbodiimide chemistry. In that perspective, several different characterization techniques were employed to investigate the new polymeric fiber platform such as scanning electron microscopy (SEM), atomic force microscopy (AFM), water contact angle (WCA) measurement and UV-vis titration. Regardless of the immobilization techniques, substantially higher signal intensity was recorded from developed platform in comparison to the conventional ELISA assay.

  16. Study of multi-functional electrospun composite nanofibrous mats for smart wound healing.

    PubMed

    Tan, Lin; Hu, Jinlian; Huang, Huahua; Han, Jianping; Hu, Huawen

    2015-08-01

    Composite nanofibers derived from synthetic and natural polymers normally show desirable characteristics in biomedical applications. In this study, composite nanofibrous mats (denoted as CNMs) with diameters of around 300 nm were fabricated facilely using blends of chitosan, gelatin and shape memory polyurethane (SMPU) by electrospinning and subsequent post-treatment with a silver nitrate solution. The obtained CNMs have shape memory effect and show desirable water vapor transmission ratio, surface wettability, satisfactory biological properties including antibacterial activity against the common Gram-negative and Gram-positive bacteria, cytocompatibility demonstrated to fibroblast, and the hemostatic property through a whole-blood clotting test. In addition, such CNMs can possibly benefit the wound healing through shape fixation-assisted easy processing and shape recovery-assisted closure of cracked wounds, which can be fine-tuned by pre-programming. Therefore, the CNMs presented in this study can be used as potential smart wound dressings.

  17. Study of multi-functional electrospun composite nanofibrous mats for smart wound healing.

    PubMed

    Tan, Lin; Hu, Jinlian; Huang, Huahua; Han, Jianping; Hu, Huawen

    2015-08-01

    Composite nanofibers derived from synthetic and natural polymers normally show desirable characteristics in biomedical applications. In this study, composite nanofibrous mats (denoted as CNMs) with diameters of around 300 nm were fabricated facilely using blends of chitosan, gelatin and shape memory polyurethane (SMPU) by electrospinning and subsequent post-treatment with a silver nitrate solution. The obtained CNMs have shape memory effect and show desirable water vapor transmission ratio, surface wettability, satisfactory biological properties including antibacterial activity against the common Gram-negative and Gram-positive bacteria, cytocompatibility demonstrated to fibroblast, and the hemostatic property through a whole-blood clotting test. In addition, such CNMs can possibly benefit the wound healing through shape fixation-assisted easy processing and shape recovery-assisted closure of cracked wounds, which can be fine-tuned by pre-programming. Therefore, the CNMs presented in this study can be used as potential smart wound dressings. PMID:26003301

  18. Electrospun Gelatin Fibers with a Multiple Release of Antibiotics Accelerate Dermal Regeneration in Infected Deep Burns.

    PubMed

    Chen, Jianmei; Liu, Zongguang; Chen, Maohua; Zhang, Hong; Li, Xiaohong

    2016-09-01

    Electrospun fibers of hydrophilic polymers meet challenges in a rapid degradation of fiber matrices and discharge of antibiotics to comply with requirements of infection control as a dermal regeneration template. In the current study, a pH conversion process is initially developed to ensure fluent electrospinning, an efficient in situ cross-linking of electrospun gelatin fibers with oxidized alginate and simultaneous loading of gentamicin sulfate (GS) and hydrophobic ciprofloxacin into fibers. The dual drug-loaded fibers indicate a complete release of GS during 6 d and a sustained release of ciprofloxacin for over three weeks, and the antibiotics release indicates significant growth inhibitions on Pseudomonas aeruginosa and Staphylococcus epidermidis. The wound healing efficacy is evaluated on a deep burn model infected with 10(8) CFU of P. aeruginosa. Compared with fibers with loaded individual drugs, the concomitant release of GS and ciprofloxacin significantly reduces the bacteria numbers in wound and livers, at around 2.30 × 10(5) and 1.25 × 10(3) CFU after 3 d, respectively. The wound re-epithelization, blood vessel formation, collagen deposition, and tissue remodeling process are accelerated with a complete healing observed after 21 d. This study provides a feasible strategy to design cross-linked hydrophilic fibers with an extended drug release for biomedical applications. PMID:27276339

  19. Electrospun fibers immobilized with bone forming peptide-1 derived from BMP7 for guided bone regeneration.

    PubMed

    Lee, Young Jun; Lee, Ji-Hye; Cho, Hyeong-Jin; Kim, Hyung Keun; Yoon, Taek Rim; Shin, Heungsoo

    2013-07-01

    The development of ideal barrier membranes with appropriate porosity and bioactivity is essential for the guidance of new bone formation in orthopedic and craniomaxillofacial surgery. In this study, we developed bioactive electrospun fibers based on poly (lactide-co-glycolic acid) (PLGA) by immobilizing bone-forming peptide 1 (BFP1) derived from the immature region of bone morphogenetic protein 7 (BMP7). We exploited polydopamine chemistry for the immobilization of BFP1; polydopamine (PD) was coated on the electrospun PLGA fibers, on which BFP1 was subsequently immobilized under weakly basic conditions. The immobilization of BFP1 was verified by characterizing the surface chemical composition and quantitatively measured by fluorescamine assay. The immobilization of BPF1 on the electrospun fibers supported the compact distribution of collagen I and the spreading of human mesenchymal stem cells (hMSCs). SEM micrographs demonstrated the aggregation of globular mineral accretions, with significant increases in ALP activity and calcium deposition when hMSCs were cultured on fibers immobilized with BFP1 for 14 days. We then implanted the prepared fibers onto mouse calvarial defects and analyzed bone formation after 2 months. Semi-quantification of bone growth from representative X-ray images showed that the bone area was approximately 20% in the defect-only group, while the group implanted with PLGA fibers showed significant improvements of 44.27 ± 7.37% and 57.59 ± 15.24% in the groups implanted with PD-coated PLGA and with BFP1-coated PLGA, respectively. Based on these results, our approach may be a promising tool to develop clinically-applicable bioactive membranes for guided bone regeneration."

  20. Controlled release of 6-aminonicotinamide from aligned, electrospun fibers alters astrocyte metabolism and dorsal root ganglia neurite outgrowth

    NASA Astrophysics Data System (ADS)

    Schaub, Nicholas J.; Gilbert, Ryan J.

    2011-08-01

    Following central nervous system (CNS) injury, activated astrocytes form a glial scar that inhibits the migration of axons ultimately leading to regeneration failure. Biomaterials developed for CNS repair can provide local delivery of therapeutics and/or guidance mechanisms to encourage cell migration into damaged regions of the brain or spinal cord. Electrospun fibers are a promising type of biomaterial for CNS injury since these fibers can direct cellular and axonal migration while slowly delivering therapy to the injury site. In this study, it was hypothesized that inclusion of an anti-metabolite, 6-aminonicotinamide (6AN), within poly-l-lactic acid electrospun fibers could attenuate astrocyte metabolic activity while still directing axonal outgrowth. Electrospinning parameters were varied to produce highly aligned electrospun fibers that contained 10% or 20% (w/w) 6AN. 6AN release from the fiber substrates occurred continuously over 2 weeks. Astrocytes placed onto drug-releasing fibers were less active than those cultured on scaffolds without 6AN. Dorsal root ganglia placed onto control and drug-releasing scaffolds were able to direct neurites along the aligned fibers. However, neurite outgrowth was stunted by fibers that contained 20% 6AN. These results show that 6AN release from aligned, electrospun fibers can decrease astrocyte activity while still directing axonal outgrowth.

  1. Self-crimping, biodegradable, electrospun polymer microfibers.

    PubMed

    Surrao, Denver C; Hayami, James W S; Waldman, Stephen D; Amsden, Brian G

    2010-12-13

    Semicrystalline poly(l-lactide-co-ε-caprolactone) (P(LLA-CL)) was used to produce electrospun fibers with diameters on the subcellular scale. P(LLA-CL) was chosen because it is biocompatible and its chemical and physical properties are easily tunable. The use of a rotating wire mandrel as a collection device in the electrospinning process, along with high collection speeds, was used to align electrospun fibers. Upon removal of the fibers from the mandrel, the fibers shrunk in length, producing a crimp pattern characteristic of collagen fibrils in soft connective tissues. The crimping effect was determined to be a result of the residual stresses resident in the fibers due to the fiber alignment process and the difference between the operating temperature (T(op)) and the glass-transition temperature (T(g)) of the polymer. The electrospun fibers could be induced to crimp by adjusting the operating temperature to be greater than that of the polymer glass-transition temperature. Moreover, the crimped fibers exhibited a toe region in their stress-strain profile that is characteristic of collagen present in tendons and ligaments. The crimp pattern was retained during in vitro degradation over 4 weeks. Primary bovine fibroblasts seeded onto these crimped fibers attached, proliferated, and deposited extracellular matrix (ECM) molecules on the surface of the fiber mats. These self-crimping fibers hold great promise for use in tissue engineering scaffolds for connective tissues that require fibers similar in structure to that of crimped collagen fibrils. PMID:21047054

  2. Apatite coating of electrospun PLGA fibers using a PVA vehicle system carrying calcium ions.

    PubMed

    Kim, In Ae; Rhee, Sang-Hoon

    2010-01-01

    A novel method to coat electrospun poly(D,L-lactic-co-glycolic acid) (PLGA) fiber surfaces evenly and efficiently with low-crystalline carbonate apatite crystals using a poly(vinyl alcohol) (PVA) vehicle system carrying calcium ions was presented. A non-woven PLGA fabric was prepared by electrospinning: a 10 wt% PLGA solution was prepared using 1,1,3,3-hexafluoro-2-propanol as a solvent and electrospun under a electrical field of 1 kV/cm using a syringe pump with a flowing rate of 3 ml/h. The non-woven PLGA fabric, 12 mm in diameter and 1 mm in thickness, was cut and then coated with a PVA solution containing calcium chloride dihydrate (specimen PPC). As controls, pure non-woven PLGA fabric (specimen P) and fabric coated with a calcium chloride dihydrate solution without PVA (specimen PC) were also prepared. Three specimens were exposed to simulated body fluid for 1 week and this exposure led to form uniform and complete apatite coating layer on the fiber surfaces of specimen PPC. However, no apatite had formed to the fiber surfaces of specimen P and only inhomogeneous coating occurred on the fiber surfaces of specimen PC. These results were explained in terms of the calcium chelating and adhesive properties of PVA vehicle system. The practical implication of the results is that this method provides a simple but efficient technique for coating the fiber surface of an initially non-bioactive material with low-crystalline carbonate apatite.

  3. Electrospun carbon nanofibers for improved electrical conductivity of fiber reinforced composites

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

    Polyacrylonitrile (PAN) was dissolved in dimethylformamide (DMF), and then electrospun to generate nanofibers using various electrospinning conditions, such as pump speeds, DC voltages and tip-to-collector distances. The produced nanofibers were oxidized at 270 °C for 1 hr, and then carbonized at 850 °C in an argon gas for additional 1 hr. The resultant carbonized PAN nanofibers were placed on top of the pre-preg carbon fiber composites as top layers prior to the vacuum oven curing following the pre-preg composite curing procedures. The major purpose of this study is to determine if the carbonized nanofibers on the fiber reinforced composites can detect the structural defects on the composite, which may be useful for the structural health monitoring (SHM) of the composites. Scanning electron microscopy images showed that the electrospun PAN fibers were well integrated on the pre-preg composites. Electrical conductivity studies under various tensile loads revealed that nanoscale carbon fibers on the fiber reinforced composites detected small changes of loads by changing the resistance values. Electrically conductive composite manufacturing can have huge benefits over the conventional composites primarily used for the military and civilian aircraft and wind turbine blades.

  4. Electrospun fiber constructs for vocal fold tissue engineering: effects of alignment and elastomeric polypeptide coating

    PubMed Central

    Hughes, Lindsay A.; Gaston, Joel; McAlindon, Katherine; Woodhouse, Kimberly A.

    2014-01-01

    Vocal fold lamina propria extracellular matrix (ECM) is highly aligned and when injured, becomes disorganized with loss of the tissue’s critical biomechanical properties. This study examines the effects of electrospun fiber scaffold architecture and elastin-like polypeptide (ELP4) coating on human vocal fold fibroblast (HVFF) behavior for applications toward tissue engineering the vocal fold lamina propria. Electrospun Tecoflex™ scaffolds were made with aligned and unaligned fibers, and were characterized using scanning electron microscopy and uniaxial tensile testing. ELP4 was successfully adsorbed onto the scaffolds; HVFF were seeded and their viability, proliferation, morphology, and gene expression were characterized. Aligned and unaligned scaffolds had initial elastic moduli of ~14 MPa, ~5 MPa and ~0.3 MPa, ~0.6 MPa in the preferred and cross-preferred directions, respectively. Scaffold topography had an effect on the orientation of the cells, with HVFF seeded on aligned scaffolds having a significantly different (p < 0.001) angle of orientation than HVFF cultured on unaligned scaffolds. This same effect and significant difference (p < 0.001) was seen on aligned and unaligned scaffolds coated with ELP4. Scaffold alignment and ELP4 coating impacted ECM gene expression. ELP4 coating, and aligned scaffolds upregulated elastin synthesis when tested on day 7 without a concomitant upregulation of collagen III synthesis. Collectively, results indicate that aligned electrospun scaffolds and ELP4 coating, are promising candidates in the development of biodegradeable vocal fold lamina propria constructs. PMID:25462850

  5. Antibacterial poly(lactic acid) (PLA) films grafting electrospun PLA/Ally isothioscyanate (AITC) fibers for food packaging

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poly(lactic acid) (PLA) fibers of submicron sizes encapsulating allyl isothiocyanate (AITC) (PfA) were made and electrospun onto the surfaces of PLA films (PfA-g-film). SEM examination confirmed that the fibers were grafted to the PLA film after the (PfA-g-film) underwent air blowing and water washi...

  6. Ionic liquid assisted electrospun cellulose acetate fibers for aqueous removal of triclosan.

    PubMed

    Zhang, Gong; Sun, Meng; Liu, Yang; Liu, Huijuan; Qu, Jiuhui; Li, Jinghong

    2015-02-10

    The cellulose acetate (CA) membrane prepared via electrospun was innovatively utilized as fiber-adsorbent for the separation of aqueous triclson (TCS). It was found that the presence of the room temperature ionic liquid (RTIL) in the precursor amplified electric force toward the CA-solution, thereby benefiting the formation of CA fibers. The as-spun CA fibers exhibit excellent adsorptive performance toward TCS, with fast adsorption kinetics, and the maximum adsorption capacity achieved to 797.7 mg g(-1), which established much better performance in contrast to conventional adsorbents. We proposed that the adsorption of TCS onto CA fibers was primarily facilitated by the hydrogen bonding between the abundant carbonyl, hydroxyl groups of CA surface, and the hydrogen atoms of phenol functional groups in TCS molecular.

  7. Electrospun polyacrylonitrile nanocomposite fibers reinforced with iron nitrate nanoparticles

    NASA Astrophysics Data System (ADS)

    Mohammed, Asif

    The methodology of preparing pure Polyacrylonitrile (PAN) fibers and magnetic PAN/FeNO3 composite Nanofibers is the traditional electrospinning process where fibers of diameter ranging less than 100 nm and larger lengths can be sophisticatedly produced on laboratory bench. With varying properties of polymer concentration, voltage and other parameters pure PAN fibers and those loaded with FeNO3 are produced. Analysis of those prepared fibers has been done through a series of experiments like SEM, FITR and X-ray Diffraction. SEM analysis explains the formation of fibers and leads to the selection of best possible ones for future methods of rheological and TGA analysis. In the past where similar contributions have been done for the fibers with FeO and Fe3O4 and the Nanoparticles, the same mentioned procedure replaces them with FeNO3. On the whole, uniform bead-less fibers are obtained and their behaviors' are studied as well. Also, graphical information for correlating the size of fibers and their polymer concentrations has been obtained. TGA analysis for recording their stability under different thermal conditions is reported. Anilining methods using microwave equipment are done instead of conventional ones.

  8. Chitosan-coated electrospun PLA fibers for rapid mineralization of calcium phosphate.

    PubMed

    Lin, Chi-Chang; Fu, Shu-Juan; Lin, Yu-Ching; Yang, I-Kuan; Gu, Yesong

    2014-07-01

    In this work, hydroxyapatite (HA) mineralized on chitosan (CS)-coated poly(lactic acid) (PLA) nanofiber mat was prepared and compared in terms of mineralization characteristics. Significant calcium phosphate crystals formed on various concentrations of CS-coated PLA fiber mat with better uniformity after 2h of incubation in 10 times simulated body fluid (10× SBF). X-ray diffraction results further indicated that the composition of the deposited mineral was a mixture of dicalcium phosphate dehydrates and apatite. Chitosan, a cationic polysaccharide, can promote more nucleation and growth of calcium phosphate under conditions of 0.4% chitosan concentrations. These results indicated that HA-mineralized on CS-coated PLA fiber mat can be prepared directly via simply using CS coating followed by SBF immersion, and the results also suggest that this composite can mimic structural, compositional, and biological functions of native bone and can serve as a good candidate for bone tissue engineering (BTE). PMID:24768970

  9. The Potential to Improve Cell Infiltration in Composite Fiber-Aligned Electrospun Scaffolds by the Selective Removal of Sacrificial Fibers

    PubMed Central

    Baker, Brendon M.; Gee, Albert O.; Metter, Robert B.; Nathan, Ashwin S.; Marklein, Ross L.; Burdick, Jason A.; Mauck, Robert L.

    2008-01-01

    Aligned electrospun scaffolds are a promising tool for engineering fibrous musculoskeletal tissues as they reproduce the mechanical anisotropy of these tissues and can direct ordered neo-tissue formation. However, these scaffolds suffer from a slow cellular infiltration rate, likely due in part to their dense fiber packing. We hypothesized that cell ingress could be expedited in scaffolds by increasing porosity, while at the same time preserving overall scaffold anisotropy. To test this hypothesis, poly(ε-caprolactone) (a slow-degrading polyester) and poly(ethylene oxide) (a water-soluble polymer) were co-electrospun from two separate spinnerets to form dual-polymer composite fiber-aligned scaffolds. Adjusting fabrication parameters produced aligned scaffolds with a full range of sacrificial (PEO) fiber contents. Tensile properties of scaffolds were a function of the ratio of PCL to PEO in the composite scaffolds, and were altered in a predictable fashion with removal of the PEO component. When seeded with mesenchymal stem cells (MSCs), increases in the starting sacrificial fraction (and porosity) improved cell infiltration and distribution after three weeks in culture. In pure PCL scaffolds, cells lined the scaffold periphery, while scaffolds containing >50% sacrificial PEO content had cells present throughout the scaffold. These findings indicate that cell infiltration can be expedited in dense fibrous assemblies with the removal of sacrificial fibers. This strategy may enhance in vitro and in vivo formation and maturation of a functional constructs for fibrous tissue engineering. PMID:18313138

  10. Creep anomaly in electrospun fibers made of globular proteins

    NASA Astrophysics Data System (ADS)

    Regev, Omri; Arinstein, Arkadii; Zussman, Eyal

    2013-12-01

    The anomalous responses of electrospun nanofibers and film fabricated of unfolded bovine serum albumin (BSA) under constant stress (creep) is observed. In contrast to typical creep behavior of viscoelastic materials demonstrating (after immediate elastic response) a time-dependent elongation, in case of low applied stresses (<1 MPa) the immediate elastic response of BSA samples is followed by gradual contraction up to 2%. Under higher stresses (2-6 MPa) the contraction phase changes into elongation; and in case of stresses above 7 MPa only elongation was observed, with no initial contraction. The anomalous creep behavior was not observed when the BSA samples were subjected to additional creep cycles independently on the stress level. The above anomaly, which was not observed before either for viscoelastic solids or for polymers, is related to specific protein features, namely, to the ability to fold. We hypothesize that the phenomenon is caused by folding of BSA macromolecules into dry molten globule states, feasible after cross-linked bonds break up, resulting from the applied external force.

  11. Creep anomaly in electrospun fibers made of globular proteins.

    PubMed

    Regev, Omri; Arinstein, Arkadii; Zussman, Eyal

    2013-12-01

    The anomalous responses of electrospun nanofibers and film fabricated of unfolded bovine serum albumin (BSA) under constant stress (creep) is observed. In contrast to typical creep behavior of viscoelastic materials demonstrating (after immediate elastic response) a time-dependent elongation, in case of low applied stresses (<1 MPa) the immediate elastic response of BSA samples is followed by gradual contraction up to 2%. Under higher stresses (2-6 MPa) the contraction phase changes into elongation; and in case of stresses above 7 MPa only elongation was observed, with no initial contraction. The anomalous creep behavior was not observed when the BSA samples were subjected to additional creep cycles independently on the stress level. The above anomaly, which was not observed before either for viscoelastic solids or for polymers, is related to specific protein features, namely, to the ability to fold. We hypothesize that the phenomenon is caused by folding of BSA macromolecules into dry molten globule states, feasible after cross-linked bonds break up, resulting from the applied external force. PMID:24483479

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

    NASA Technical Reports Server (NTRS)

    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.

  13. Neurite outgrowth on electrospun PLLA fibers is enhanced by exogenous electrical stimulation

    NASA Astrophysics Data System (ADS)

    Koppes, A. N.; Zaccor, N. W.; Rivet, C. J.; Williams, L. A.; Piselli, J. M.; Gilbert, R. J.; Thompson, D. M.

    2014-08-01

    Objective. Both electrical stimuli (endogenous and exogenous) and topographical cues are instructive to axonal extension. This report, for the first time, investigated the relative dominance of directional topographical guidance cues and directional electrical cues to enhance and/or direct primary neurite extension. We hypothesized the combination of electrical stimulation with electrospun fiber topography would induce longer neurite extension from dorsal root ganglia neurons than the presence of electrical stimulation or aligned topography alone. Approach. To test the hypothesis, neurite outgrowth was examined on laminin-coated poly-L-lactide films or electrospun fibers (2 µm in diameter) in the presence or absence of electrical stimulation. Immunostained neurons were semi-automatically traced using Neurolucida software and morphology was evaluated. Main Results. Neurite extension increased 74% on the aligned fibers compared to film controls. Stimulation alone increased outgrowth by 32% on films or fibers relative to unstimulated film controls. The co-presentation of topographical (fibers) with biophysical (electrical stimulation) cues resulted in a synergistic 126% increase in outgrowth relative to unstimulated film controls. Field polarity had no influence on the directionality of neurites, indicating topographical cues are responsible for guiding neurite extension. Significance. Both cues (electrical stimulation and fiber geometry) are modular in nature and can be synergistically applied in conjunction with other common methods in regenerative medicine such as controlled release of growth factors to further influence axonal growth in vivo. The combined application of electrical and aligned fiber topographical guidance cues described herein, if translated in vivo, could provide a more supportive environment for directed and robust axonal regeneration following peripheral nerve injury.

  14. Neurite Outgrowth On Electrospun PLLA Fibers Is Enhanced By Exogenous Electrical Stimulation

    PubMed Central

    Koppes, A. N.; Zaccor, N. W.; Rivet, C. J.; Williams, L. A.; Piselli, J. M.; Gilbert, R. J.; Thompson, D. M.

    2014-01-01

    Objective Both electrical stimuli (endogenous and exogenous) and topographical cues are instructive to axonal extension. This report, for the first time, investigated the relative dominance of directional topographical guidance cues and directional electrical cues to enhance and/or direct primary neurite extension. We hypothesized the combination of electrical stimulation with electrospun fiber topography would induce longer neurite extension from DRG neurons than the presence of electrical stimulation or aligned topography alone. Approach To test the hypothesis, neurite outgrowth was examined on laminin-coated poly-L-lactide (PLLA) films or electrospun fibers (2 μm in diameter) in the presence or absence of electrical stimulation. Immunostained neurons were semi-automatically traced using Neurolucida software and morphology was evaluated. Results Neurite extension increased 74% on the aligned fibers compared to film controls. Stimulation alone increased outgrowth by 32% on films or fibers relative to unstimulated film controls. The co-presentation of topographical (fibers) with biophysical (electrical stimulation) cues resulted in a synergistic 126% increase in outgrowth relative to unstimulated film controls. Field polarity had no influence on the directionality of neurite, indicating topographical cues are responsible to guide neurite extension. Significance Both cues (electrical stimulation and fiber geometry) are modular in nature and can be synergistically applied in conjunction with other common methods in regenerative medicine such as controlled release of growth factors to further influence axonal growth in vivo. The combined application of electrical and aligned fiber topographical guidance cues described herein, if translated in vivo, could provide a more supportive environment for directed and robust axonal regeneration following peripheral nerve injury. PMID:24891494

  15. Electrospun Poly(ε-caprolactone)/Polyhedral Oligomeric Silsesquioxane-Based Copolymer Blends: Evolution of Fiber Internal Structures.

    PubMed

    Bauer, Adam J P; Wu, Yitian; Li, Bingbing

    2016-05-01

    This study reports the structural transition of electrospun poly(ε-caprolactone) (PCL)/poly[(propylmethacryl-heptaisobutyl-polyhedral oligomeric silsesquioxane)-co-(methyl meth-acrylate)] (POSS-MMA) blends, from PCL-rich fibers, to bicontinuous PCL core/POSS-MMA shell fibers, to POSS-MMA-rich fibers with a discontinuous PCL inner phase. A ternary phase diagram depicting the electrospinnability of PCL/POSS-MMA solutions is constructed by evaluating the morphological features of fibers electrospun from solutions with various concentrations and PCL/POSS-MMA blend ratios. X-ray diffraction, Raman spectroscopy, and differential scanning calorimetry are further used to characterize the electrospun PCL/POSS-MMA hybrid fibers. These physicochemical characterization results are thoroughly discussed to understand the internal structures of the hybrid fibers, which are directly correlated to the phase separation behavior of the electrospun solutions. The current study provides further insight into the complex phase behavior of POSS-copolymer-based systems, which hold great potential for a broad spectrum of biomedical applications. PMID:26782272

  16. Electrospun polylactic acid and polyvinyl alcohol fibers as efficient and stable nanomaterials for immobilization of lipases.

    PubMed

    Sóti, Péter Lajos; Weiser, Diana; Vigh, Tamás; Nagy, Zsombor Kristóf; Poppe, László; Marosi, György

    2016-03-01

    Electrospinning was applied to create easy-to-handle and high-surface-area membranes from continuous nanofibers of polyvinyl alcohol (PVA) or polylactic acid (PLA). Lipase PS from Burkholderia cepacia and Lipase B from Candida antarctica (CaLB) could be immobilized effectively by adsorption onto the fibrous material as well as by entrapment within the electrospun nanofibers. The biocatalytic performance of the resulting membrane biocatalysts was evaluated in the kinetic resolution of racemic 1-phenylethanol (rac-1) and 1-phenylethyl acetate (rac-2). Fine dispersion of the enzymes in the polymer matrix and large surface area of the nanofibers resulted in an enormous increase in the activity of the membrane biocatalyst compared to the non-immobilized crude powder forms of the lipases. PLA as fiber-forming polymer for lipase immobilization performed better than PVA in all aspects. Recycling studies with the various forms of electrospun membrane biocatalysts in ten cycles of the acylation and hydrolysis reactions indicated excellent stability of this forms of immobilized lipases. PLA-entrapped lipases could preserve lipase activity and enantiomer selectivity much better than the PVA-entrapped forms. The electrospun membrane forms of CaLB showed high mechanical stability in the repeated acylations and hydrolyses than commercial forms of CaLB immobilized on polyacrylamide beads (Novozyme 435 and IMMCALB-T2-150).

  17. Electrospun polylactic acid and polyvinyl alcohol fibers as efficient and stable nanomaterials for immobilization of lipases.

    PubMed

    Sóti, Péter Lajos; Weiser, Diana; Vigh, Tamás; Nagy, Zsombor Kristóf; Poppe, László; Marosi, György

    2016-03-01

    Electrospinning was applied to create easy-to-handle and high-surface-area membranes from continuous nanofibers of polyvinyl alcohol (PVA) or polylactic acid (PLA). Lipase PS from Burkholderia cepacia and Lipase B from Candida antarctica (CaLB) could be immobilized effectively by adsorption onto the fibrous material as well as by entrapment within the electrospun nanofibers. The biocatalytic performance of the resulting membrane biocatalysts was evaluated in the kinetic resolution of racemic 1-phenylethanol (rac-1) and 1-phenylethyl acetate (rac-2). Fine dispersion of the enzymes in the polymer matrix and large surface area of the nanofibers resulted in an enormous increase in the activity of the membrane biocatalyst compared to the non-immobilized crude powder forms of the lipases. PLA as fiber-forming polymer for lipase immobilization performed better than PVA in all aspects. Recycling studies with the various forms of electrospun membrane biocatalysts in ten cycles of the acylation and hydrolysis reactions indicated excellent stability of this forms of immobilized lipases. PLA-entrapped lipases could preserve lipase activity and enantiomer selectivity much better than the PVA-entrapped forms. The electrospun membrane forms of CaLB showed high mechanical stability in the repeated acylations and hydrolyses than commercial forms of CaLB immobilized on polyacrylamide beads (Novozyme 435 and IMMCALB-T2-150). PMID:26724947

  18. Thickness-controllable electrospun fibers promote tubular structure formation by endothelial progenitor cells

    PubMed Central

    Hong, Jong Kyu; Bang, Ju Yup; Xu, Guan; Lee, Jun-Hee; Kim, Yeon-Ju; Lee, Ho-Jun; Kim, Han Seong; Kwon, Sang-Mo

    2015-01-01

    Controlling the thickness of an electrospun nanofibrous scaffold by altering its pore size has been shown to regulate cell behaviors such as cell infiltration into a three-dimensional (3D) scaffold. This is of great importance when manufacturing tissue-engineering scaffolds using an electrospinning process. In this study, we report the development of a novel process whereby additional aluminum foil layers were applied to the accumulated electrospun fibers of an existing aluminum foil collector, effectively reducing the incidence of charge buildup. Using this process, we fabricated an electrospun scaffold with a large pore (pore size >40 μm) while simultaneously controlling the thickness. We demonstrate that the large pore size triggered rapid infiltration (160 μm in 4 hours of cell culture) of individual endothelial progenitor cells (EPCs) and rapid cell colonization after seeding EPC spheroids. We confirmed that the 3D, but not two-dimensional, scaffold structures regulated tubular structure formation by the EPCs. Thus, incorporation of stem cells into a highly porous 3D scaffold with tunable thickness has implications for the regeneration of vascularized thick tissues and cardiac patch development. PMID:25709441

  19. Improvement of hydrophilic properties of electrospun polyamide-imide fibrous mats by atmospheric-pressure plasma treatment

    NASA Astrophysics Data System (ADS)

    Park, Soo-Jin; Yop Rhee, Kyong; Jin, Fan-Long

    2015-03-01

    Polyamide-imide (PAI) fibrous mats were fabricated through electrospinning and further treated with atmospheric-pressure plasma. The surface characteristics of the PAI fibrous mats were examined to determine the effect of plasma treatment on the hydrophilic properties. FT-IR, X-ray photoelectron spectroscopy, and contact-angle analysis indicated that the hydrophilicity of the PAI fibrous mats increased upon the introduction of hydrophilic groups by plasma treatment. The concentration of functional groups, including oxygen, and the surface roughness of the PAI fibrous mats increased with increasing treatment time. The optimum plasma treatment time for surface modification of the PAI fibrous mats under atmospheric pressure was 120 s.

  20. Effect of Sterilization Methods on Electrospun Poly(lactic acid) (PLA) Fiber Alignment for Biomedical Applications.

    PubMed

    Valente, T A M; Silva, D M; Gomes, P S; Fernandes, M H; Santos, J D; Sencadas, V

    2016-02-10

    Medically approved sterility methods should be a major concern when developing a polymeric scaffold, mainly when commercialization is envisaged. In the present work, poly(lactic acid) (PLA) fiber membranes were processed by electrospinning with random and aligned fiber alignment and sterilized under UV, ethylene oxide (EO), and γ-radiation, the most common ones for clinical applications. It was observed that UV light and γ-radiation do not influence fiber morphology or alignment, while electrospun samples treated with EO lead to fiber orientation loss and morphology changing from cylindrical fibers to ribbon-like structures, accompanied to an increase of polymer crystallinity up to 28%. UV light and γ-radiation sterilization methods showed to be less harmful to polymer morphology, without significant changes in polymer thermal and mechanical properties, but a slight increase of polymer wettability was detected, especially for the samples treated with UV radiation. In vitro results indicate that both UV and γ-radiation treatments of PLA membranes allow the adhesion and proliferation of MG 63 osteoblastic cells in a close interaction with the fiber meshes and with a growth pattern highly sensitive to the underlying random or aligned fiber orientation. These results are suggestive of the potential of both γ-radiation sterilized PLA membranes for clinical applications in regenerative medicine, especially those where customized membrane morphology and fiber alignment is an important issue. PMID:26756809

  1. Elastic-plastic behavior of non-woven fibrous mats

    NASA Astrophysics Data System (ADS)

    Silberstein, Meredith N.; Pai, Chia-Ling; Rutledge, Gregory C.; Boyce, Mary C.

    2012-02-01

    Electrospinning is a novel method for creating non-woven polymer mats that have high surface area and high porosity. These attributes make them ideal candidates for multifunctional composites. Understanding the mechanical properties as a function of fiber properties and mat microstructure can aid in designing these composites. Further, a constitutive model which captures the membrane stress-strain behavior as a function of fiber properties and the geometry of the fibrous network would be a powerful design tool. Here, mats electrospun from amorphous polyamide are used as a model system. The elastic-plastic behavior of single fibers are obtained in tensile tests. Uniaxial monotonic and cyclic tensile tests are conducted on non-woven mats. The mat exhibits elastic-plastic stress-strain behavior. The transverse strain behavior provides important complementary data, showing a negligible initial Poisson's ratio followed by a transverse:axial strain ratio greater than -1:1 after an axial strain of 0.02. A triangulated framework has been developed to emulate the fibrous network structure of the mat. The micromechanically based model incorporates the elastic-plastic behavior of single fibers into a macroscopic membrane model of the mat. This representative volume element based model is shown to capture the uniaxial elastic-plastic response of the mat under monotonic and cyclic loading. The initial modulus and yield stress of the mat are governed by the fiber properties, the network geometry, and the network density. The transverse strain behavior is linked to discrete deformation mechanisms of the fibrous mat structure including fiber alignment, fiber bending, and network consolidation. The model is further validated in comparison to experiments under different constrained axial loading conditions and found to capture the constraint effect on stiffness, yield, post-yield hardening, and post-yield transverse strain behavior. Due to the direct connection between

  2. Ofloxacin Loaded Electrospun Fibers for Ocular Drug Delivery: Effect of Formulation Variables on Fiber Morphology and Drug Release.

    PubMed

    Karataş, Ayşegül; Algan, Aslihan Hilal; Pekel-Bayramgil, Nursel; Turhan, Fatih; Altanlar, Nurten

    2016-01-01

    Ofloxacin (OFL) loaded poly(ε-caprolactone) (PCL) and PCL: poly(butylene succinate) PBS fibers as a drug delivery system in the treatment of ocular infections were prepared by electrospinning. In particular, the effect of some formulation variables including polymer:drug ratio (9:1, 8:2 and 7:3 w/w), solvent systems like dichloromethane (DCM), N,N-dimethylformamide (DMF), N,Ndimethylacetamide (DMAc) and dimethylsulfoxide (DMSO), polymer blends of PCL:PBS at 80:20, 60:40 and 40:60 ratios on fiber morphology, fiber size were investigated. The morphology and diameter of the electrospun fibers were investigated by scanning electron microscopy (SEM) images also the thermal properties were evaluated by differential scanning calorimetry (DSC). The drug release behaviour from fibers and in vitro antibacterial activity were also studied. It was noticed that the average fiber diameter decreased with decreasing polymer amount in initial composition meanwhile the release of drug increased with increasing amount of drug in formulations. Solvent system of DCM:DMF at 80:20 ratio improved fiber morphology and resulted in a reduction in fiber diameter. It was found that smooth surface, flexible fibers with uniform morphology were obtained with 80:20 ratio of PCL:PBS compositions. All fibers showed a burst release of OFL. The initial amount of the released OFL was found to vary as a function of PCL:OFL ratio and polymer composition in the fiber. The microbiological activity of optimized formulation was evaluated using P. aeruginosa, S. epidermidis, S. Aureus and E. coli strains and the results of this study clearly demonstrated that freely released OFL from fibers inhibited the growth of the tested bacteria. The process of electrospinning had no adverse effect on the activity of incorporated drug in fibers.

  3. Ofloxacin Loaded Electrospun Fibers for Ocular Drug Delivery: Effect of Formulation Variables on Fiber Morphology and Drug Release.

    PubMed

    Karataş, Ayşegül; Algan, Aslihan Hilal; Pekel-Bayramgil, Nursel; Turhan, Fatih; Altanlar, Nurten

    2016-01-01

    Ofloxacin (OFL) loaded poly(ε-caprolactone) (PCL) and PCL: poly(butylene succinate) PBS fibers as a drug delivery system in the treatment of ocular infections were prepared by electrospinning. In particular, the effect of some formulation variables including polymer:drug ratio (9:1, 8:2 and 7:3 w/w), solvent systems like dichloromethane (DCM), N,N-dimethylformamide (DMF), N,Ndimethylacetamide (DMAc) and dimethylsulfoxide (DMSO), polymer blends of PCL:PBS at 80:20, 60:40 and 40:60 ratios on fiber morphology, fiber size were investigated. The morphology and diameter of the electrospun fibers were investigated by scanning electron microscopy (SEM) images also the thermal properties were evaluated by differential scanning calorimetry (DSC). The drug release behaviour from fibers and in vitro antibacterial activity were also studied. It was noticed that the average fiber diameter decreased with decreasing polymer amount in initial composition meanwhile the release of drug increased with increasing amount of drug in formulations. Solvent system of DCM:DMF at 80:20 ratio improved fiber morphology and resulted in a reduction in fiber diameter. It was found that smooth surface, flexible fibers with uniform morphology were obtained with 80:20 ratio of PCL:PBS compositions. All fibers showed a burst release of OFL. The initial amount of the released OFL was found to vary as a function of PCL:OFL ratio and polymer composition in the fiber. The microbiological activity of optimized formulation was evaluated using P. aeruginosa, S. epidermidis, S. Aureus and E. coli strains and the results of this study clearly demonstrated that freely released OFL from fibers inhibited the growth of the tested bacteria. The process of electrospinning had no adverse effect on the activity of incorporated drug in fibers. PMID:26521656

  4. Local Mechanical Properties of Electrospun Fibers Correlate to Their Internal Nanostructure

    PubMed Central

    2013-01-01

    The properties of polymeric nanofibers can be tailored and enhanced by properly managing the structure of the polymer molecules at the nanoscale. Although electrospun polymer fibers are increasingly exploited in many technological applications, their internal nanostructure, determining their improved physical properties, is still poorly investigated and understood. Here, we unravel the internal structure of electrospun functional nanofibers made by prototype conjugated polymers. The unique features of near-field optical measurements are exploited to investigate the nanoscale spatial variation of the polymer density, evidencing the presence of a dense internal core embedded in a less dense polymeric shell. Interestingly, nanoscale mapping the fiber Young’s modulus demonstrates that the dense core is stiffer than the polymeric, less dense shell. These findings are rationalized by developing a theoretical model and simulations of the polymer molecular structural evolution during the electrospinning process. This model predicts that the stretching of the polymer network induces a contraction of the network toward the jet center with a local increase of the polymer density, as observed in the solid structure. The found complex internal structure opens an interesting perspective for improving and tailoring the molecular morphology and multifunctional electronic and optical properties of polymer fibers. PMID:24090350

  5. Enhanced emission efficiency in electrospun polyfluorene copolymer fibers

    NASA Astrophysics Data System (ADS)

    Morello, Giovanni; Polini, Alessandro; Girardo, Salvatore; Camposeo, Andrea; Pisignano, Dario

    2013-05-01

    We report on the unique emission features of light-emitting fibers made of a prototype conjugated polymer, namely, poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(1,4-benzo-{2,1'-3}-thiadiazole)] (F8BT), realized by electrospinning with diameters in the range of 500-1000 nm. The fibers display emission polarized along their axis, evidencing a favoured alignment of the polymer molecules. Emission efficiency and time resolved measurements reveal an enhancement of both the quantum efficiency and the radiative rate (up to 22.5%) of the fibers compared to spin-coated films, shedding more light on their potential as miniaturized photon sources in optoelectronic devices requiring high recombination rates.

  6. Controlled Antibiotics Release System through Simple Blended Electrospun Fibers for Sustained Antibacterial Effects.

    PubMed

    Zhang, Zixin; Tang, Jianxiong; Wang, Heran; Xia, Qinghua; Xu, Shanshan; Han, Charles C

    2015-12-01

    Implantation of sustained antibacterial system after abdominal surgery could effectively prevent complicated intra-abdominal infection. In this study, a simple blended electrospun membrane made of poly(D,L-lactic-co-glycolide) (PLGA)/poly(dioxanone) (PDO)/Ciprofloxacin hydrochloride (CiH) could easily result in approximately linear drug release profile and sustained antibacterial activity against both Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The addition of PDO changed the stack structure of PLGA, which in turn influenced the fiber swelling and created drug diffusion channels. It could be a good candidate for reducing postoperative infection or be associated with other implant to resist biofilm formation. PMID:26596498

  7. Electrospun TiO(2) fiber composite photoelectrodes for water splitting.

    PubMed

    Regonini, D; Teloeken, A C; Alves, A K; Berutti, F A; Gajda-Schrantz, K; Bergmann, C P; Graule, T; Clemens, F

    2013-11-27

    This work has focused on the development of electrospun TiO2 fiber composite photoelectrodes for hydrogen production by water splitting. For comparison, similar photoelectrodes were also developed using commercial TiO2 (Aeroxide P25) nanoparticles (NPs). Dispersions of either fibers or P25 NPs were used to make homogenous TiO2 films on fluorine-doped SnO2 (FTO) glass substrates by a doctor blade (DB) technique. Scanning electron microscopy (SEM) analysis revealed a much lower packing density of the DB fibers, with respect to DB-P25 TiO2 NPs; this was also directly reflected by the higher photocurrent measured for the NPs when irradiating the photoelectrodes at a light intensity of 1.5AM (1 sun, 1000 W/m(2)). For a better comparison of fibers vs. NPs, composite photoelectrodes by dip-coating (onto FTO) TiO2 sol-gel (SG) matrixes containing an equal amount (5 or 20 wt %) of either fibers or P25 NPs were also investigated. It emerged that the photoactivity of the fibers was significantly higher. For composites containing 5 wt % TiO2 fibers, a photocurrent of 0.5 mA/cm(2) (at 0.23 V vs Ag/AgCl) was measured, whereas 5 wt % P25 NPs only provided 0.2 mA/cm(2). When increasing to 20 wt % fibers or NPs, the photocurrent decreased, because of the formation of microcracks in the photoelectrodes, because of the shrinkage of the sol-gel. The high photoactivity of the fiber-based electrodes could be confirmed by incident photon to current efficiency (IPCE) measurements. Remarkably, the IPCE of composites containing 5 wt % fibers was between 35% and 40% in the region of 380-320 nm, and when accounting for transmission/reflection losses, the absorbed photon to current efficiency (APCE) was consistently over 60% between 380 nm and 320 nm. The superior photoactivity is attributed to the enhanced electron transport in the electrospun fibers, with respect to P25 NPs. According to this study, it is clear that the electronic connectivity ensured by the sol-gel also

  8. Optimization of fully aligned bioactive electrospun fibers for "in vitro" nerve guidance.

    PubMed

    Cirillo, Valentina; Guarino, Vincenzo; Alvarez-Perez, Marco Antonio; Marrese, Marica; Ambrosio, Luigi

    2014-10-01

    Complex architecture of natural tissues such as nerves requires the use of multifunctional scaffolds with peculiar topological and biochemical signals able to address cell behavior towards specific events at the cellular (microscale) and macromolecular (nanoscale) level. In this context, the electrospinning technique is useful to generate fiber assemblies having peculiar fiber diameters at the nanoscale and patterned by unidirectional ways, to facilitate neurite extension via contact guidance. Following a bio-mimetic approach, fully aligned polycaprolactone fibers blended with gelatin macromolecules have been fabricated as potential bioactive substrate for nerve regeneration. Morphological and topographic aspects of electrospun fibers assessed by SEM/AFM microscopy supported by image analyses elaboration allow estimating an increase of fully aligned fibers from 5 to 39% as collector rotating rate increases from 1,000 to 3,000 rpm. We verify that fully alignment of fibers positively influences in vitro response of hMSC and PC-12 cells in neurogenic way. Immunostaining images show that the presence of topological defects, i.e., kinks--due to more frequent fiber crossing--in the case of randomly organized fiber assembly concurs to interfere with proper neurite outgrowth. On the contrary, fully aligned fibers without kinks offer a more efficient contact guidance to direct the orientation of nerve cells along the fibers respect to randomly organized ones, promoting a high elongation of neurites at 7 days and the formation of bipolar extensions. So, this confirms that the topological cue of fully alignment of fibers elicits a favorable environment for nerve regeneration.

  9. Hydrolyzed Poly(acrylonitrile) Electrospun Ion-Exchange Fibers

    PubMed Central

    Jassal, Manisha; Bhowmick, Sankha; Sengupta, Sukalyan; Patra, Prabir K.; Walker, Douglas I.

    2014-01-01

    Abstract A potential ion-exchange material was developed from poly(acrylonitrile) fibers that were prepared by electrospinning followed by alkaline hydrolysis (to convert the nitrile group to the carboxylate functional group). Characterization studies performed on this material using X-ray photoelectron spectroscopy, scanning electron microscopy, Fourier-Transform infra-red spectroscopy, and ion chromatography confirmed the presence of ion-exchange functional group (carboxylate). Optimum hydrolysis conditions resulted in an ion-exchange capacity of 2.39 meq/g. Ion-exchange fibers were used in a packed-bed column to selectively remove heavy-metal cation from the background of a benign, competing cation at a much higher concentration. The material can be efficiently regenerated and used for multiple cycles of exhaustion and regeneration. PMID:24963270

  10. In vitro biodegradation of designed tubular scaffolds of electrospun protein/polyglyconate blend fibers.

    PubMed

    Zhang, Xing; Thomas, Vinoy; Vohra, Yogesh K

    2009-04-01

    Electrospun polyglyconate (Maxon) and its blends with proteins such as gelatin and elastin, with a spatially designed layer structure, were prepared as potential scaffolds for vascular tissue engineering. In vitro biodegradation of the electrospun tubular protein/Maxon scaffolds in phosphate buffered saline (pH = 7.3) was studied for the first time. The biodegradation is manifested by uptake of the PBS medium by the hydrophilic proteins and also by the mass loss due to the removal of degraded fragments and uncrosslinked proteins from the matrices. The effect of degradation on the structure-property relations was evaluated by IR, XRD, and DSC analyses of the aged scaffolds. The degradation of amorphous phase of Maxon in the early stages of aging has resulted in an increase in the crystallinity of the polymer. SEM analysis indicated a significant change in nanofiber morphology and fiber-breaking. The mass loss and fiber breaking have negatively impacted the mechanical properties and the effect was maximum at 15-20 days of aging. The scaffold containing low molecular weight buffer soluble elastin revealed relatively better degradation properties compared to that containing high molecular weight buffer insoluble elastin.

  11. Fabrication of Gelatin-Based Electrospun Composite Fibers for Anti-Bacterial Properties and Protein Adsorption

    PubMed Central

    Gao, Ya; Wang, Yingbo; Wang, Yimin; Cui, Wenguo

    2016-01-01

    A major goal of biomimetics is the development of chemical compositions and structures that simulate the extracellular matrix. In this study, gelatin-based electrospun composite fibrous membranes were prepared by electrospinning to generate bone scaffold materials. The gelatin-based multicomponent composite fibers were fabricated using co-electrospinning, and the composite fibers of chitosan (CS), gelatin (Gel), hydroxyapatite (HA), and graphene oxide (GO) were successfully fabricated for multi-function characteristics of biomimetic scaffolds. The effect of component concentration on composite fiber morphology, antibacterial properties, and protein adsorption were investigated. Composite fibers exhibited effective antibacterial activity against Staphylococcus aureus and Escherichia coli. The study observed that the composite fibers have higher adsorption capacities of bovine serum albumin (BSA) at pH 5.32–6.00 than at pH 3.90–4.50 or 7.35. The protein adsorption on the surface of the composite fiber increased as the initial BSA concentration increased. The surface of the composite reached adsorption equilibrium at 20 min. These results have specific applications for the development of bone scaffold materials, and broad implications in the field of tissue engineering. PMID:27775645

  12. Modulation of anisotropy in electrospun tissue-engineering scaffolds: Analysis of fiber alignment by the fast Fourier transform

    PubMed Central

    Ayres, Chantal; Bowlin, Gary L.; Henderson, Scott C.; Taylor, Leander; Shultz, Jackie; Alexander, John; Telemeco, Todd A.; Simpson, David G.

    2010-01-01

    We describe the use of the fast Fourier transform (FFT) in the measurement of anisotropy in electrospun scaffolds of gelatin as a function of the starting conditions. In electrospinning, fiber alignment and overall scaffold anisotropy can be manipulated by controlling the motion of the collecting mandrel with respect to the source electrospinning solution. By using FFT to assign relative alignment values to an electrospun matrix it is possible to systematically evaluate how different processing variables impact the structure and material properties of a scaffold. Gelatin was suspended at varying concentrations (80, 100, 130, 150 mg/ml) and electrospun from 2,2,2 trifluoroethanol onto rotating mandrels (200–7000 RPM). At each starting concentration, fiber diameter remained constant over a wide range of mandrel RPM. Scaffold anisotropy developed as a function of fiber diameter and mandrel RPM. The induction of varying degrees of anisotropy imparted distinctive material properties to the electrospun scaffolds. The FFT is a rapid method for evaluating fiber alignment in tissue-engineering materials. PMID:16859744

  13. Advances in electrospun carbon fiber-based electrochemical sensing platforms for bioanalytical applications.

    PubMed

    Mao, Xianwen; Tian, Wenda; Hatton, T Alan; Rutledge, Gregory C

    2016-02-01

    Electrochemical sensing is an efficient and inexpensive method for detection of a range of chemicals of biological, clinical, and environmental interest. Carbon materials-based electrodes are commonly employed for the development of electrochemical sensors because of their low cost, biocompatibility, and facile electron transfer kinetics. Electrospun carbon fibers (ECFs), prepared by electrospinning of a polymeric precursor and subsequent thermal treatment, have emerged as promising carbon systems for biosensing applications since the electrochemical properties of these carbon fibers can be easily modified by processing conditions and post-treatment. This review addresses recent progress in the use of ECFs for sensor fabrication and analyte detection. We focus on the modification strategies of ECFs and identification of the key components that impart the bioelectroanalytical activities, and point out the future challenges that must be addressed in order to advance the fundamental understanding of the ECF electrochemistry and to realize the practical applications of ECF-based sensing devices. PMID:26650731

  14. Advances in electrospun carbon fiber-based electrochemical sensing platforms for bioanalytical applications.

    PubMed

    Mao, Xianwen; Tian, Wenda; Hatton, T Alan; Rutledge, Gregory C

    2016-02-01

    Electrochemical sensing is an efficient and inexpensive method for detection of a range of chemicals of biological, clinical, and environmental interest. Carbon materials-based electrodes are commonly employed for the development of electrochemical sensors because of their low cost, biocompatibility, and facile electron transfer kinetics. Electrospun carbon fibers (ECFs), prepared by electrospinning of a polymeric precursor and subsequent thermal treatment, have emerged as promising carbon systems for biosensing applications since the electrochemical properties of these carbon fibers can be easily modified by processing conditions and post-treatment. This review addresses recent progress in the use of ECFs for sensor fabrication and analyte detection. We focus on the modification strategies of ECFs and identification of the key components that impart the bioelectroanalytical activities, and point out the future challenges that must be addressed in order to advance the fundamental understanding of the ECF electrochemistry and to realize the practical applications of ECF-based sensing devices.

  15. Evaluation of electrospun polyvinyl chloride/polystyrene fibers as sorbent materials for oil spill cleanup.

    PubMed

    Zhu, Haitao; Qiu, Shanshan; Jiang, Wei; Wu, Daxiong; Zhang, Canying

    2011-05-15

    A novel, high-capacity oil sorbent consisting of polyvinyl chloride (PVC)/polystyrene (PS) fiber was prepared by an electrospinning process. The sorption capacity, oil/water selectivity, and sorption mechanism of the PVC/PS sorbent were studied. The results showed that the sorption capacities of the PVC/PS sorbent for motor oil, peanut oil, diesel, and ethylene glycol were 146, 119, 38, and 81 g/g, respectively. It was about 5-9 times that of a commercial polypropylene (PP) sorbent. The PVC/PS sorbent also had excellent oil/water selectivity (about 1000 times) and high buoyancy in the cleanup of oil over water. The SEM analysis indicated that voids among fibers were the key for the high capacity. The electrospun PVC/PS sorbent is a better alternative to the widely used PP sorbent for oil spill cleanup.

  16. Superhydrophobic and superoleophillic surface of porous beaded electrospun polystrene and polysytrene-zeolite fiber for crude oil-water separation

    NASA Astrophysics Data System (ADS)

    Alayande, S. Oluwagbemiga; Dare, E. Olugbenga; Msagati, Titus A. M.; Akinlabi, A. Kehinde; Aiyedun, P. O.

    2016-04-01

    This research presents a cheap route procedure for the preparation of a potential adsorbent with superhydrophobic/superoleophillic properties for selective removal of crude oil from water. In this study, expanded polystyrene (EPS) was electrospun to produce beaded fibers in which zeolite was introduced to the polymer matrix in order to impart rough surface to non-beaded fiber. Films of the EPS and EPS/Zeolite solutions were also made for comparative study. The electrospun fibers EPS, EPS/Zeolite and resultant films were characterized using SEM, BET, FTIR and optical contact angle. The fibers exhibited superhydrophobic and superoleophillic wetting properties with water (>1500) and crude oil (00). The selective removal of crude oil presents new opportunity for the re-use of EPS as adsorbent in petroleum/petrochemical industry.

  17. Manufacturing scale-up of electrospun poly(vinyl alcohol) fibers containing tenofovir for vaginal drug delivery

    PubMed Central

    Krogstad, Emily A.; Woodrow, Kim A.

    2014-01-01

    Electrospun fibers containing antiretroviral drugs have recently been investigated as a new dosage form for topical microbicides against HIV-1. However, little work has been done to evaluate the scalability of the fiber platform for pharmaceutical production of medical fabrics. Scalability and cost-effectiveness are essential criteria in developing fibers as a practical platform for use as a microbicide and for translation to clinical use. To address this critical gap in the development of fiber-based vaginal dosage forms, we assessed the scale-up potential of drug-eluting fibers delivering tenofovir (TFV), a nucleotide reverse transcriptase inhibitor and lead compound for topical HIV-1 chemoprophylaxis. Here we describe the process of free-surface electrospinning to scale up production of TFV fibers, and evaluate key attributes of the finished products such as fiber morphology, drug crystallinity, and drug loading and release kinetics. Poly(vinyl alcohol) (PVA) containing up to 60 wt% TFV was successfully electrospun into fibers using a nozzle-free production-scale electrospinning instrument. Actual TFV loading in fibers increased with increasing weight percent TFV in solution, and encapsulation efficiency was improved by maintaining TFV solubility and preventing drug sedimentation during batch processing. These results define important solution and processing parameters for scale-up production of TFV drug-eluting fibers by wire electrospinning, which may have significant implications for pharmaceutical manufacturing of fiber-based medical fabrics for clinical use. PMID:25169075

  18. Immobilized laminin concentration gradients on electrospun fiber scaffolds for controlled neurite outgrowth.

    PubMed

    Zander, Nicole E; Beebe, Thomas P

    2014-03-01

    Neuronal process growth is guided by extrinsic environmental cues such as extracellular matrix (ECM) proteins. Recent reports have described that the growth cone extension is superior across gradients of the ECM protein laminin compared to growth across uniformly distributed laminin. In this work, the authors have prepared gradients of laminin on aligned electrospun nanofibers for use as substrates for neuronal growth. The substrates therefore presented both topographical and chemical guidance cues. Step gradients were prepared by the controlled robotic immersion of plasma-treated polycaprolactone fibers reacted with N-hydroxysuccinimide into the protein solution. The gradients were analyzed using x-ray photoelectron spectroscopy and confocal laser scanning microscopy. Gradients with a dynamic range of protein concentrations were successfully generated and neurite outgrowth was evaluated using neuronlike pheochromocytoma cell line 12 (PC12) cells. After 10 days of culture, PC12 neurite lengths varied from 32.7 ± 14.2 μm to 76.3 ± 9.1 μm across the protein concentration gradient. Neurite lengths at the highest concentration end of the gradient were significantly longer than neurite lengths observed for cells cultured on samples with uniform protein coverage. Gradients were prepared both in the fiber direction and transverse to the fiber direction. Neurites preferentially aligned with the fiber direction in both cases indicating that fiber alignment has a more dominant role in controlling neurite orientation, compared to the chemical gradient. PMID:24739010

  19. Desalination by Membrane Distillation using Electrospun Polyamide Fiber Membranes with Surface Fluorination by Chemical Vapor Deposition.

    PubMed

    Guo, Fei; Servi, Amelia; Liu, Andong; Gleason, Karen K; Rutledge, Gregory C

    2015-04-22

    Fibrous membranes of poly(trimethyl hexamethylene terephthalamide) (PA6(3)T) were fabricated by electrospinning and rendered hydrophobic by applying a conformal coating of poly(1H,1H,2H,2H-perfluorodecyl acrylate) (PPFDA) using initiated chemical vapor deposition (iCVD). A set of iCVD-treated electrospun PA6(3)T fiber membranes with fiber diameters ranging from 0.25 to 1.8 μm were tested for desalination using the air gap membrane distillation configuration. Permeate fluxes of 2-11 kg/m2/h were observed for temperature differentials of 20-45 °C between the feed stream and condenser plate, with rejections in excess of 99.98%. The liquid entry pressure was observed to increase dramatically, from 15 to 373 kPa with reduction in fiber diameter. Contrary to expectation, for a given feed temperature the permeate flux was observed to increase for membranes of decreasing fiber diameter. The results for permeate flux and salt rejection show that it is possible to construct membranes for membrane distillation even from intrinsically hydrophilic materials after surface modification by iCVD and that the fiber diameter is shown to play an important role on the membrane distillation performance in terms of permeate flux, salt rejection, and liquid entry pressure. PMID:25835769

  20. Desalination by Membrane Distillation using Electrospun Polyamide Fiber Membranes with Surface Fluorination by Chemical Vapor Deposition.

    PubMed

    Guo, Fei; Servi, Amelia; Liu, Andong; Gleason, Karen K; Rutledge, Gregory C

    2015-04-22

    Fibrous membranes of poly(trimethyl hexamethylene terephthalamide) (PA6(3)T) were fabricated by electrospinning and rendered hydrophobic by applying a conformal coating of poly(1H,1H,2H,2H-perfluorodecyl acrylate) (PPFDA) using initiated chemical vapor deposition (iCVD). A set of iCVD-treated electrospun PA6(3)T fiber membranes with fiber diameters ranging from 0.25 to 1.8 μm were tested for desalination using the air gap membrane distillation configuration. Permeate fluxes of 2-11 kg/m2/h were observed for temperature differentials of 20-45 °C between the feed stream and condenser plate, with rejections in excess of 99.98%. The liquid entry pressure was observed to increase dramatically, from 15 to 373 kPa with reduction in fiber diameter. Contrary to expectation, for a given feed temperature the permeate flux was observed to increase for membranes of decreasing fiber diameter. The results for permeate flux and salt rejection show that it is possible to construct membranes for membrane distillation even from intrinsically hydrophilic materials after surface modification by iCVD and that the fiber diameter is shown to play an important role on the membrane distillation performance in terms of permeate flux, salt rejection, and liquid entry pressure.

  1. Application of glass-fiber reinforced plastic (GRP) mud-mats for Daria-A platform

    SciTech Connect

    Bertorelli, D.; Spessa, A.

    1994-12-31

    A review of the experience gained with glass-fiber reinforced plastic (GRP) mud-mat materials used for the Garibaldi-C jacket, in the Adriatic sea, has shown that this solution can result in substantial cost savings. Therefore, Agip has investigated a further use of GRP mud-mats for the Daria-A platform as a means of reducing the lifting weight of the jacket and, moreover, to negate the requirement for additional buoyancy tanks during the free flotation and upending phases. Two possible solutions, the ``pultrusion`` and the ``lamination`` techniques, have been investigated to fabricate sandwich panels for the mud-mats. In this paper these two technologies are discussed with respect to their application to the construction and they are compared on a performance and cost basis.

  2. Tuning the conductivity and inner structure of electrospun fibers to promote cardiomyocyte elongation and synchronous beating.

    PubMed

    Liu, Yaowen; Lu, Jinfu; Xu, Guisen; Wei, Jiaojun; Zhang, Zhibin; Li, Xiaohong

    2016-12-01

    The key to addressing the challenges facing cardiac tissue engineering is the integration of physical, chemical, and electrical cues into scaffolds. Aligned and conductive scaffolds have been fabricated as synthetic microenvironments to improve the function of cardiomyocytes. However, up to now, the influence of conductive capability and inner structure of fibrous scaffolds have not been determined on the cardiomyocyte morphologies and beating patterns. In the current study, highly aligned fibers were fabricated with loaded up to 6% of carbon nanotubes (CNTs) to modulate the electrical conductivity, while blend and coaxial electrospinning were utilized to create a bulk distribution of CNTs in fiber matrices and a spatial embedment in fiber cores, respectively. Conductive networks were formed in the fibrous scaffolds after the inoculation of over 3% CNTs, and the increase in the conductivity could maintain the cell viabilities, induce the cell elongation, enhance the production of sarcomeric α-actinin and troponin I, and promote the synchronous beating of cardiomyocytes. Although the conductivity of blend fibers is slightly higher than that of coaxial fibers with the same CNT loadings, the lower exposures to CNTs resulted in higher cell viability, elongation, extracellular matrix secretion and beating rates for cardiomyocytes on coaxial fibers. Taken altogether, core-sheath fibers with loaded 5% of CNTs in the fiber cores facilitated the cardiomyocyte growth with a production of organized contractile proteins and a pulsation frequency close to that of the atrium. It is suggested that electrospun scaffolds that couple conductivity and fibrous structure considerations may provide optimal stimuli to foster cell morphology and functions for myocardial regeneration or establishment of in vitro cardiomyocyte culture platform for drug screening.

  3. Tuning the conductivity and inner structure of electrospun fibers to promote cardiomyocyte elongation and synchronous beating.

    PubMed

    Liu, Yaowen; Lu, Jinfu; Xu, Guisen; Wei, Jiaojun; Zhang, Zhibin; Li, Xiaohong

    2016-12-01

    The key to addressing the challenges facing cardiac tissue engineering is the integration of physical, chemical, and electrical cues into scaffolds. Aligned and conductive scaffolds have been fabricated as synthetic microenvironments to improve the function of cardiomyocytes. However, up to now, the influence of conductive capability and inner structure of fibrous scaffolds have not been determined on the cardiomyocyte morphologies and beating patterns. In the current study, highly aligned fibers were fabricated with loaded up to 6% of carbon nanotubes (CNTs) to modulate the electrical conductivity, while blend and coaxial electrospinning were utilized to create a bulk distribution of CNTs in fiber matrices and a spatial embedment in fiber cores, respectively. Conductive networks were formed in the fibrous scaffolds after the inoculation of over 3% CNTs, and the increase in the conductivity could maintain the cell viabilities, induce the cell elongation, enhance the production of sarcomeric α-actinin and troponin I, and promote the synchronous beating of cardiomyocytes. Although the conductivity of blend fibers is slightly higher than that of coaxial fibers with the same CNT loadings, the lower exposures to CNTs resulted in higher cell viability, elongation, extracellular matrix secretion and beating rates for cardiomyocytes on coaxial fibers. Taken altogether, core-sheath fibers with loaded 5% of CNTs in the fiber cores facilitated the cardiomyocyte growth with a production of organized contractile proteins and a pulsation frequency close to that of the atrium. It is suggested that electrospun scaffolds that couple conductivity and fibrous structure considerations may provide optimal stimuli to foster cell morphology and functions for myocardial regeneration or establishment of in vitro cardiomyocyte culture platform for drug screening. PMID:27612781

  4. A simple green route to obtain poly(vinyl alcohol) electrospun mats with improved water stability for use as potential carriers of drugs.

    PubMed

    López-Córdoba, Alex; Castro, Guillermo R; Goyanes, Silvia

    2016-12-01

    Poly(vinyl alcohol) (PVA) is a hydrophilic, biocompatible and nontoxic polymer. However, because of its low water-resistance, some applications for PVA-based materials are limited (e.g., drug delivery systems and wound dressings). In the current work, PVA mats containing tetracycline hydrochloride (TC) were successfully developed by electrospinning. In order to improve the water stability of the systems, the cross-linking of the PVA matrix was induced by citric acid (CA) addition together with heating treatments (150°C or 190°C for 3min). TC presence led to a strong increase in the electrical conductivity of the blends and as a result, fibers with about 44% lower diameter (270nm) than that of the corresponding unloaded mats (485nm) were obtained. Laser scanning confocal microscopy images indicated that TC was well distributed along the PVA nanofibers. The mats were evaluated by FTIR, which revealed chemical interactions between PVA hydroxyl groups and CA carboxylic ones. The treatment at 150°C for 3min proved to be the more suitable for the preparation of TC-containing mats with improved water resistance, maintaining the TC antimicrobial activity against both Escherichia coli and Staphylococcus aureus almost unaltered. These mats showed a burst release of TC, giving around 95% of the drug within the first hour of immersion in water. PMID:27612766

  5. A simple green route to obtain poly(vinyl alcohol) electrospun mats with improved water stability for use as potential carriers of drugs.

    PubMed

    López-Córdoba, Alex; Castro, Guillermo R; Goyanes, Silvia

    2016-12-01

    Poly(vinyl alcohol) (PVA) is a hydrophilic, biocompatible and nontoxic polymer. However, because of its low water-resistance, some applications for PVA-based materials are limited (e.g., drug delivery systems and wound dressings). In the current work, PVA mats containing tetracycline hydrochloride (TC) were successfully developed by electrospinning. In order to improve the water stability of the systems, the cross-linking of the PVA matrix was induced by citric acid (CA) addition together with heating treatments (150°C or 190°C for 3min). TC presence led to a strong increase in the electrical conductivity of the blends and as a result, fibers with about 44% lower diameter (270nm) than that of the corresponding unloaded mats (485nm) were obtained. Laser scanning confocal microscopy images indicated that TC was well distributed along the PVA nanofibers. The mats were evaluated by FTIR, which revealed chemical interactions between PVA hydroxyl groups and CA carboxylic ones. The treatment at 150°C for 3min proved to be the more suitable for the preparation of TC-containing mats with improved water resistance, maintaining the TC antimicrobial activity against both Escherichia coli and Staphylococcus aureus almost unaltered. These mats showed a burst release of TC, giving around 95% of the drug within the first hour of immersion in water.

  6. Whey protein concentrate doped electrospun poly(epsilon-caprolactone) fibers for antibiotic release improvement.

    PubMed

    Ahmed, Said Mahmoud; Ahmed, Hanaa; Tian, Chang; Tu, Qin; Guo, Yadan; Wang, Jinyi

    2016-07-01

    Design and fabrication of scaffolds using appropriate biomaterials are a key step for the creation of functionally engineered tissues and their clinical applications. Poly(epsilon-caprolactone) (PCL), a biodegradable and biocompatible material with negligible cytotoxicity, is widely used to fabricate nanofiber scaffolds by electrospinning for the applications of pharmaceutical products and wound dressings. However, the use of PCL as such in tissue engineering is limited due to its poor bioregulatory activity, high hydrophobicity, lack of functional groups and neutral charge. With the attempt to found nanofiber scaffolds with antibacterial activity for skin tissue engineering, in this study, whey protein concentrate (WPC) was used to modify the PCL nanofibers by doping it in the PCL electrospun solution. By adding proteins into PCL nanofibers, the degradability of the fibers may be increased, and this further allows an antibiotic incorporated in the fibers to be efficiently released. The morphology, wettability and degradation of the as-prepared PCL/WPC nanofibers were carefully characterized. The results showed that the PCL/WPC nanofibers possessed good morphology and wettability, as well as high degradation ability to compare with the pristine PCL fibers. Afterwords, tetracycline hydrochloride as a model antibiotic drug was doped in the PCL/WPC nanofibers. In vitro drug release assays demonstrated that PCL/WPC nanofibers had higher antibiotic release capability than the PCL nanofibers. Also, antibacterial activity evaluation against various bacteria showed that the drug-doped PCL/WPC fibers possessed more efficient antibacterial activity than the PCL nanofibers. PMID:27022878

  7. Preparation and characterization of naproxen-loaded electrospun thermoplastic polyurethane nanofibers as a drug delivery system.

    PubMed

    Akduman, Cigdem; Özgüney, Işık; Kumbasar, E Perrin Akcakoca

    2016-07-01

    The design and production of drug-loaded nanofiber based materials produced by electrospinning is of interest for use in innovative drug delivery systems. In the present study, ultra-fine fiber mats of thermoplastic polyurethane (TPU) containing naproxen (NAP) were successfully prepared by electrospinning from 8 and 10% (w/w) TPU solutions. The amount of NAP in the solutions was 10 and 20% based on the weight of TPU. The collection period of the drug-loaded electrospun TPU fibers was 5, 10 and 20h, and they were characterized by FTIR, DSC and TGA analysis. The morphology of the NAP-loaded electrospun TPU fiber mats was smooth, and the average diameters of these fibers varied between 523.66 and 723.50nm. The release characteristics of these fiber mats were determined by the total immersion method in the phosphate buffer solution at 37°C. It was observed that the collection period in terms of the mat thickness played a major role in the release rate of NAP from the electrospun TPU mats. PMID:27127068

  8. A method to integrate patterned electrospun fibers with microfluidic systems to generate complex microenvironments for cell culture applications

    PubMed Central

    Wallin, Patric; Zandén, Carl; Carlberg, Björn; Hellström Erkenstam, Nina; Liu, Johan; Gold, Julie

    2012-01-01

    The properties of a cell’s microenvironment are one of the main driving forces in cellular fate processes and phenotype expression invivo. The ability to create controlled cell microenvironments invitro becomes increasingly important for studying or controlling phenotype expression in tissue engineering and drug discovery applications. This includes the capability to modify material surface properties within well-defined liquid environments in cell culture systems. One successful approach to mimic extra cellular matrix is with porous electrospun polymer fiber scaffolds, while microfluidic networks have been shown to efficiently generate spatially and temporally defined liquid microenvironments. Here, a method to integrate electrospun fibers with microfluidic networks was developed in order to form complex cell microenvironments with the capability to vary relevant parameters. Spatially defined regions of electrospun fibers of both aligned and random orientation were patterned on glass substrates that were irreversibly bonded to microfluidic networks produced in poly-dimethyl-siloxane. Concentration gradients obtained in the fiber containing channels were characterized experimentally and compared with values obtained by computational fluid dynamic simulations. Velocity and shear stress profiles, as well as vortex formation, were calculated to evaluate the influence of fiber pads on fluidic properties. The suitability of the system to support cell attachment and growth was demonstrated with a fibroblast cell line. The potential of the platform was further verified by a functional investigation of neural stem cell alignment in response to orientation of electrospun fibers versus a microfluidic generated chemoattractant gradient of stromal cell-derived factor 1 alpha. The described method is a competitive strategy to create complex microenvironments invitro that allow detailed studies on the interplay of topography, substrate surface properties, and soluble

  9. Carbon Microfibers with Hierarchical Porous Structure from Electrospun Fiber-Like Natural Biopolymer

    PubMed Central

    Liang, Yeru; Wu, Dingcai; Fu, Ruowen

    2013-01-01

    Electrospinning offers a powerful route for building one-dimensional (1D) micro/nanostructures, but a common requirement for toxic or corrosive organic solvents during the preparation of precursor solution has limited their large scale synthesis and broad applications. Here we report a facile and low-cost way to prepare 1D porous carbon microfibers by using an electrospun fiber-like natural product, i.e., silk cocoon, as precursor. We surprisingly found that by utilizing a simple carbonization treatment, the cocoon microfiber can be directly transformed into 1D carbon microfiber of ca. 6 μm diameter with a unique three-dimensional porous network structure composed of interconnected carbon nanoparticles of 10~40 nm diameter. We further showed that the as-prepared carbon product presents superior electrochemical performance as binder-free electrodes of supercapacitors and good adsorption property toward organic vapor. PMID:23350027

  10. Carbon microfibers with hierarchical porous structure from electrospun fiber-like natural biopolymer.

    PubMed

    Liang, Yeru; Wu, Dingcai; Fu, Ruowen

    2013-01-01

    Electrospinning offers a powerful route for building one-dimensional (1D) micro/nanostructures, but a common requirement for toxic or corrosive organic solvents during the preparation of precursor solution has limited their large scale synthesis and broad applications. Here we report a facile and low-cost way to prepare 1D porous carbon microfibers by using an electrospun fiber-like natural product, i.e., silk cocoon, as precursor. We surprisingly found that by utilizing a simple carbonization treatment, the cocoon microfiber can be directly transformed into 1D carbon microfiber of ca. 6 μm diameter with a unique three-dimensional porous network structure composed of interconnected carbon nanoparticles of 10~40 nm diameter. We further showed that the as-prepared carbon product presents superior electrochemical performance as binder-free electrodes of supercapacitors and good adsorption property toward organic vapor. PMID:23350027

  11. Electrospun poly(L-lactic acid-co-ɛ-caprolactone) fibers loaded with heparin and vascular endothelial growth factor to improve blood compatibility and endothelial progenitor cell proliferation.

    PubMed

    Chen, Xi; Wang, Jing; An, Qingzhu; Li, Dawei; Liu, Peixi; Zhu, Wei; Mo, Xiumei

    2015-04-01

    Emulsion electrospinning is a convenient and promising method for incorporating proteins and drugs into nanofiber scaffolds. The aim of this study was to fabricate a nanofiber scaffold for anticoagulation and rapid endothelialization. For this purpose, we encapsulated heparin and vascular endothelial growth factor (VEGF) into the core of poly(L-lactic acid-co-ɛ-caprolactone) (P(LLA-CL)) core-shell nanofibers via emulsion electrospinning. The fiber morphology, core-shell structure and hydrophilicity of the nanofiber mats were analyzed by scanning electron microscopy, transmission electron microscopy and water contact angle. The blood compatibility was measured by hemolysis and anticoagulation testing. A CCK-8 assay was performed to study the promotion of endothelial progenitor cell (EPC) growth and was complemented by immunofluorescent staining and SEM. Our study demonstrates that heparin and VEGF can be incorporated into P(LLA-CL) nanofibers via emulsion. The released heparin performed well as an anticoagulant, and the released VEGF promoted EPC growth on the fiber scaffolds. These results imply that electrospun P(LLA-CL) nanofibers containing heparin and VEGF have great potential in the development of vascular grafts in cases where antithrombogenicity and accelerated endothelialization are desirable.

  12. Image-based quantification of fiber alignment within electrospun tissue engineering scaffolds is related to mechanical anisotropy.

    PubMed

    Fee, Timothy; Downs, Crawford; Eberhardt, Alan; Zhou, Yong; Berry, Joel

    2016-07-01

    It is well documented that electrospun tissue engineering scaffolds can be fabricated with variable degrees of fiber alignment to produce scaffolds with anisotropic mechanical properties. Several attempts have been made to quantify the degree of fiber alignment within an electrospun scaffold using image-based methods. However, these methods are limited by the inability to produce a quantitative measure of alignment that can be used to make comparisons across publications. Therefore, we have developed a new approach to quantifying the alignment present within a scaffold from scanning electron microscopic (SEM) images. The alignment is determined by using the Sobel approximation of the image gradient to determine the distribution of gradient angles with an image. This data was fit to a Von Mises distribution to find the dispersion parameter κ, which was used as a quantitative measure of fiber alignment. We fabricated four groups of electrospun polycaprolactone (PCL) + Gelatin scaffolds with alignments ranging from κ = 1.9 (aligned) to κ = 0.25 (random) and tested our alignment quantification method on these scaffolds. It was found that our alignment quantification method could distinguish between scaffolds of different alignments more accurately than two other published methods. Additionally, the alignment parameter κ was found to be a good predictor the mechanical anisotropy of our electrospun scaffolds. The ability to quantify fiber alignment within and make direct comparisons of scaffold fiber alignment across publications can reduce ambiguity between published results where cells are cultured on "highly aligned" fibrous scaffolds. This could have important implications for characterizing mechanics and cellular behavior on aligned tissue engineering scaffolds. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1680-1686, 2016.

  13. Regulated Non-Viral Gene Delivery from Coaxial Electrospun Fiber Mesh Scaffolds

    PubMed Central

    Saraf, Anita; Baggett, L. Scott; Raphael, Robert M.; Kasper, F. Kurtis; Mikos, Antonios G.

    2009-01-01

    concentration. Furthermore, fibroblast-like cells seeded directly onto coaxial fiber mesh scaffolds containing PEI-HA and pDNA showed EGFP expression over 60 days, which was significantly greater than the EGFP expression observed with scaffolds containing pDNA alone. Hence, variable transfection activity can be achieved over extended periods of time upon release of pDNA and non-viral gene delivery vectors from electrospun coaxial fiber mesh scaffolds, with release and subsequent transfection controlled by tunable coaxial fiber mesh fabrication parameters. PMID:20006660

  14. Enhanced performance of electrospun carbon fibers modified with carbon nanotubes: promising electrodes for enzymatic biofuel cells

    NASA Astrophysics Data System (ADS)

    Both Engel, A.; Cherifi, A.; Tingry, S.; Cornu, D.; Peigney, A.; Laurent, Ch

    2013-06-01

    New nanostructured electrodes, promising for the production of clean and renewable energy in biofuel cells, were developed with success. For this purpose, carbon nanofibers were produced by the electrospinning of polyacrylonitrile solution followed by convenient thermal treatments (stabilization followed by carbonization at 1000, 1200 and 1400° C), and carbon nanotubes were adsorbed on the surfaces of the fibers by a dipping method. The morphology of the developed electrodes was characterized by several techniques (SEM, Raman spectroscopy, electrical conductivity measurement). The electrochemical properties were evaluated through cyclic voltammetry, where the influence of the carbonization temperature of the fibers and the beneficial contribution of the carbon nanotubes were observed through the reversibility and size of the redox peaks of K3Fe(CN)6 versus Ag/AgCl. Subsequently, redox enzymes were immobilized on the electrodes and the electroreduction of oxygen to water was realized as a test of their efficiency as biocathodes. Due to the fibrous and porous structure of these new electrodes, and to the fact that carbon nanotubes may have the ability to promote electron transfer reactions of redox biomolecules, the new electrodes developed were capable of producing higher current densities than an electrode composed only of electrospun carbon fibers.

  15. Electrospun core-shell fibers for robust silicon nanoparticle-based lithium ion battery anodes.

    PubMed

    Hwang, Tae Hoon; Lee, Yong Min; Kong, Byung-Seon; Seo, Jin-Seok; Choi, Jang Wook

    2012-02-01

    Because of its unprecedented theoretical capacity near 4000 mAh/g, which is approximately 10-fold larger compared to those of the current commercial graphite anodes, silicon has been the most promising anode for lithium ion batteries, particularly targeting large-scale energy storage applications including electrical vehicles and utility grids. Nevertheless, Si suffers from its short cycle life as well as the limitation for scalable electrode fabrication. Herein, we develop an electrospinning process to produce core-shell fiber electrodes using a dual nozzle in a scalable manner. In the core-shell fibers, commercially available nanoparticles in the core are wrapped by the carbon shell. The unique core-shell structure resolves various issues of Si anode operations, such as pulverization, vulnerable contacts between Si and carbon conductors, and an unstable sold-electrolyte interphase, thereby exhibiting outstanding cell performance: a gravimetric capacity as high as 1384 mAh/g, a 5 min discharging rate capability while retaining 721 mAh/g, and cycle life of 300 cycles with almost no capacity loss. The electrospun core-shell one-dimensional fibers suggest a new design principle for robust and scalable lithium battery electrodes suffering from volume expansion.

  16. Enhanced performance of electrospun carbon fibers modified with carbon nanotubes: promising electrodes for enzymatic biofuel cells.

    PubMed

    Engel, A Both; Cherifi, A; Tingry, S; Cornu, D; Peigney, A; Laurent, Ch

    2013-06-21

    New nanostructured electrodes, promising for the production of clean and renewable energy in biofuel cells, were developed with success. For this purpose, carbon nanofibers were produced by the electrospinning of polyacrylonitrile solution followed by convenient thermal treatments (stabilization followed by carbonization at 1000, 1200 and 1400° C), and carbon nanotubes were adsorbed on the surfaces of the fibers by a dipping method. The morphology of the developed electrodes was characterized by several techniques (SEM, Raman spectroscopy, electrical conductivity measurement). The electrochemical properties were evaluated through cyclic voltammetry, where the influence of the carbonization temperature of the fibers and the beneficial contribution of the carbon nanotubes were observed through the reversibility and size of the redox peaks of K3Fe(CN)6 versus Ag/AgCl. Subsequently, redox enzymes were immobilized on the electrodes and the electroreduction of oxygen to water was realized as a test of their efficiency as biocathodes. Due to the fibrous and porous structure of these new electrodes, and to the fact that carbon nanotubes may have the ability to promote electron transfer reactions of redox biomolecules, the new electrodes developed were capable of producing higher current densities than an electrode composed only of electrospun carbon fibers.

  17. Fabrication of electrospun biocomposites comprising polycaprolactone/fucoidan for tissue regeneration.

    PubMed

    Lee, Ji Seok; Jin, Gyu Hyun; Yeo, Myung Gu; Jang, Chul Ho; Lee, Haengnam; Kim, Geun Hyung

    2012-09-01

    In this study, we designed a new biocomposite comprising electrospun polycaprolactone (PCL)/fucoidan, in which the fucoidan has various beneficial biological functions, including anticoagulant, antiviral, and immunomodulatory activity. To obtain the composite scaffolds, a mixture of PCL and fucoidan was electrospun using various compositions (1, 2, 3, and 10 wt.%) of fucoidan powders. The resultant electrospun composites exhibited improved tensile modulus and strength for limited weight fractions (<10 wt.%) of fucoidan when compared with the pure PCL fiber mats. In addition, the biocomposites showed dramatic hydrophilic properties at >3 wt.% of fucoidan in the PCL/fucoidan. The biocompatibility of the electrospun mats was examined in vitro using osteoblast-like cells (MG63). Total protein content, alkaline phosphatase activity, and calcium mineralization were assessed. Scanning electron microscopic images showed that the cells were distributed more widely and were agglomerated on PCL/fucoidan mats compared with pure PCL mats. In addition, total protein content, alkaline phosphatase activity, and calcium mineralization were higher with PCL/fucoidan mats than with pure PCL mats. These observations suggest that fucoidan-supplemented biocomposites would make excellent materials for tissue-engineering applications. PMID:24751028

  18. Optical properties of benthic photosynthetic communities: fiber-optic studies of cyanobacterial mats.

    PubMed

    Jorgensen, B B; Des Marais, D J

    1988-01-01

    A fiber-optic microphobe was used to analyze the spectral light gradients in benthic cyanobacterial mats with 50-micrometer depth resolution and 10-nm spectral resolution. Microcoleus chthononplastes mats were collected from hypersaline, coastal ponds at Guerrero Negro, Baja California. Gradients of spectral radiance, L, were measured at different angles through the mats and the spherically integrated scalar irradiance, Eo, was calculated. Maximal spectral light attenuation was found at the absorption peaks for the dominant photosynthetic pigments: chlorophyll a at 430 and 670 nm, carotenoids at 450-500 nm, phycocyanin at 620 nm, and bacteriochlorophyll a at 800-900 nm. Scattered light had a marked spectral effect on the scalar irradiance which near the mat surface reached up to 190% of the incident irradiance. The spherically integrated irradiance thus differed strongly from the incident irradiance both in total intensity and in spectral composition. These basic optical properties are important for the understanding of photosynthesis and light harvesting in benthic and epiphytic communities.

  19. Optical properties of benthic photosynthetic communities: fiber-optic studies of cyanobacterial mats

    NASA Technical Reports Server (NTRS)

    Jorgensen, B. B.; Des Marais, D. J.

    1988-01-01

    A fiber-optic microphobe was used to analyze the spectral light gradients in benthic cyanobacterial mats with 50-micrometer depth resolution and 10-nm spectral resolution. Microcoleus chthononplastes mats were collected from hypersaline, coastal ponds at Guerrero Negro, Baja California. Gradients of spectral radiance, L, were measured at different angles through the mats and the spherically integrated scalar irradiance, Eo, was calculated. Maximal spectral light attenuation was found at the absorption peaks for the dominant photosynthetic pigments: chlorophyll a at 430 and 670 nm, carotenoids at 450-500 nm, phycocyanin at 620 nm, and bacteriochlorophyll a at 800-900 nm. Scattered light had a marked spectral effect on the scalar irradiance which near the mat surface reached up to 190% of the incident irradiance. The spherically integrated irradiance thus differed strongly from the incident irradiance both in total intensity and in spectral composition. These basic optical properties are important for the understanding of photosynthesis and light harvesting in benthic and epiphytic communities.

  20. Influence of calcination temperature on the surface area of submicron-sized Al2O3 electrospun fibers

    NASA Astrophysics Data System (ADS)

    Shin, Hyeon Ung; Ramsier, Rex D.; Chase, George G.

    2016-03-01

    Submicron-sized Al2O3 fibers were formed by calcination of electrospun aluminum acetate/PVP composite fibers. At 650 °C, the fibers were amorphous. As the calcination temperature increased to 750 °C, the fibers transitioned from amorphous to 49 % crystalline gamma phase Al2O3. The crystallinity further increased with calcination temperature to 80 % gamma Al2O3 at 950 °C, but decreased above 950 °C as the crystal structure began to change to alpha phase. The fiber diameters tended to decrease as calcination temperature increased to 950 °C but increased as the alpha phase was formed at temperatures above 950 °C. Surface areas as measured by BET decreased as gamma phase crystallinity increased. Further decrease in surface area as the gamma phase crystal structure transitioned to alpha phase indicated changing internal pore structures of the fibers.

  1. Structure−Property Correlations in Hybrid Polymer−Nanoparticle Electrospun Fibers and Plasmonic Control over their Dichroic Behavior

    SciTech Connect

    Sharma, Nikhil; McKeown, Steven J.; Ma, Xin; Pochan, Darrin J.; Cloutier, Sylvain G.

    2010-12-07

    Electrospinning constitutes a simple and versatile approach of fabricating polymer heterostructures composed of nanofibers. A preferred alignment of polymer crystallites stems from complex shear elongational forces and generates a strong intrinsic optical anisotropy in typical electrospun fibers of semicrystalline polymers. While it can prove useful for certain devices, this intrinsic anisotropy can be extremely detrimental for other key applications such as high-performance polymer-based lighting and solar-energy harvesting platforms. We report a dramatic reduction in the intrinsic dichroism of electrospun poly(ethylene oxide) fibers resulting from the incorporation of inorganic nanoparticles in the polymer matrix. This effect is shown to originate from a controllable randomization of the orientational ordering of the crystalline domains in the hybrid nanofibers and not merely from a reduction in crystallinity. This improved understanding of the crystalline structure-optical property correlation then leads to a better control over the intrinsic anisotropy of electrospun fibers using localized surface-plasmon enhancement effects around metallic nanoparticles.

  2. Conjugated polymer dots-on-electrospun fibers as a fluorescent nanofibrous sensor for nerve gas stimulant.

    PubMed

    Jo, Seonyoung; Kim, Jongho; Noh, Jaeguk; Kim, Daigeun; Jang, Geunseok; Lee, Naeun; Lee, Eunji; Lee, Taek Seung

    2014-12-24

    A novel chemical warfare agent sensor based on conjugated polymer dots (CPdots) immobilized on the surface of poly(vinyl alcohol) (PVA)-silica nanofibers was prepared with a dots-on-fibers (DoF) hybrid nanostructure via simple electrospinning and subsequent immobilization processes. We synthesized a polyquinoxaline (PQ)-based CP as a highly emissive sensing probe and employed PVA-silica as a host polymer for the elctrospun fibers. It was demonstrated that the CPdots and amine-functionalized electrospun PVA-silica nanofibers interacted via an electrostatic interaction, which was stable under prolonged mechanical force. Because the CPdots were located on the surface of the nanofibers, the highly emissive properties of the CPdots could be maintained and even enhanced, leading to a sensitive turn-off detection protocol for chemical warfare agents. The prepared fluorescent DoF hybrid was quenched in the presence of a chemical warfare agent simulant, due to the electron transfer between the quinoxaline group in the polymer and the organophosphorous simulant. The detection time was almost instantaneous, and a very low limit of detection was observed (∼1.25 × 10(-6) M) with selectivity over other organophosphorous compounds. The DoF hybrid nanomaterial can be developed as a rapid, practical, portable, and stable chemical warfare agent-detecting system and, moreover, can find further applications in other sensing systems simply by changing the probe dots immobilized on the surface of nanofibers. PMID:25431844

  3. Long-term Controlled Drug Release from bi-component Electrospun Fibers

    NASA Astrophysics Data System (ADS)

    Xu, Shanshan; Zhang, Zixin; Xia, Qinghua; Han, Charles

    Multi-drug delivery systems with timed programmed release are hard to be produced due to the complex drug release kinetics which mainly refers to the diffusion of drug molecules from the fiber and the degradation of the carrier. This study focused on the whole life-time story of the long-term drug releasing fibrous systems. Electrospun membrane utilizing FDA approved polymers and broad-spectrum antibiotics showed specific drug release profiles which could be divided into three stages based on the profile slope. With throughout morphology observation, cumulative release amount and releasing duration, releasing kinetics and critical factors were fully discussed during three stages. Through changing the second component, approximately linear drug release profile and a drug release duration about 13 days was prepared, which is perfect for preventing post-operative infection. The addition of this semi-crystalline polymer in turn influenced the fiber swelling and created drug diffusion channels. In conclusion, through adjusting and optimization of the blending component, initial burst release, delayed release for certain duration, and especially the sustained release profile could all be controlled, as well as specific anti-bacterial behavior could be obtained.

  4. Green electrospun grape seed extract-loaded silk fibroin nanofibrous mats with excellent cytocompatibility and antioxidant effect.

    PubMed

    Lin, Si; Chen, Mengxia; Jiang, Huayue; Fan, Linpeng; Sun, Binbin; Yu, Fan; Yang, Xingxing; Lou, Xiangxin; He, Chuanglong; Wang, Hongsheng

    2016-03-01

    Silk fibroin (SF) from Bombyx mori has an excellent biocompatibility and thus be widely applied in the biomedical field. Recently, various SF-based composite nanofibers have been developed for more demanding applications. Additionally, grape seed extract (GSE) has been demonstrated to be powerful on antioxidation. In the present study, we dedicate to fabricate a GSE-loaded SF/polyethylene oxide (PEO) composite nanofiber by green electrospinning. Our results indicated the successful loading of GSE into the SF/PEO composite nanofibers. The introduction of GSE did not affect the morphology of the SF/PEO nanofibers and GSE can be released from the nanofibers with a sustained manner. Furthermore, comparing with the raw SF/PEO nanofibrous mats, the GSE-loaded SF/PEO nanofibrous mats significantly enhanced the proliferation of the skin fibroblasts and also protected them against the damage from tert-butyl hydroperoxide-induced oxidative stress. All these findings suggest a promising potential of this novel GSE-loaded SF/PEO composite nanofibrous mats applied in skin care, tissue regeneration and wound healing.

  5. Green electrospun grape seed extract-loaded silk fibroin nanofibrous mats with excellent cytocompatibility and antioxidant effect.

    PubMed

    Lin, Si; Chen, Mengxia; Jiang, Huayue; Fan, Linpeng; Sun, Binbin; Yu, Fan; Yang, Xingxing; Lou, Xiangxin; He, Chuanglong; Wang, Hongsheng

    2016-03-01

    Silk fibroin (SF) from Bombyx mori has an excellent biocompatibility and thus be widely applied in the biomedical field. Recently, various SF-based composite nanofibers have been developed for more demanding applications. Additionally, grape seed extract (GSE) has been demonstrated to be powerful on antioxidation. In the present study, we dedicate to fabricate a GSE-loaded SF/polyethylene oxide (PEO) composite nanofiber by green electrospinning. Our results indicated the successful loading of GSE into the SF/PEO composite nanofibers. The introduction of GSE did not affect the morphology of the SF/PEO nanofibers and GSE can be released from the nanofibers with a sustained manner. Furthermore, comparing with the raw SF/PEO nanofibrous mats, the GSE-loaded SF/PEO nanofibrous mats significantly enhanced the proliferation of the skin fibroblasts and also protected them against the damage from tert-butyl hydroperoxide-induced oxidative stress. All these findings suggest a promising potential of this novel GSE-loaded SF/PEO composite nanofibrous mats applied in skin care, tissue regeneration and wound healing. PMID:26707696

  6. Electrospun Collagen Fibers with Spatial Patterning of SDF1α for the Guidance of Neural Stem Cells.

    PubMed

    Li, Xiaoran; Liang, Hui; Sun, Jie; Zhuang, Yan; Xu, Bai; Dai, Jianwu

    2015-08-26

    Producing gradients of biological cues into nerve conduits is crucial for nerve guidance and regeneration. Herein, the fabrication of gradients of stromal cell-derived factor-1α (SDF1α) on electrospun collagen mats is reported using an electrohydrodynamic jet printing technique. The fabrication of various SDF1α gradated patterns on collagen fibrous mats is successfully demonstrated including shallow continuous gradient, steep continuous gradient, and step gradient by controlling the processing parameters. The SDF1α graded collagen scaffolds show a long-term stable gradient, as SDF1α is fused with a unique peptide of collagen binding domain (CBD), and CBD-SDF1α can specifically bind to the collagen mat. Such graded scaffolds exhibit sustained release of SDF1α. Further examination of neural stem cell (NSC) response to the CBD-SDF1α gradients with various patterns show that the NSCs can sense the CBD-SDF1α gradients, display a polarized morphology, and tend to migrate toward the region with a higher CBD-SDF1α content. The collagen mats with CBD-SDF1α gradients guide gradual distribution of NSCs, and NSC-differentiated neurons and astrocytes after seeding for 1 and 7 d. This new class of CBD-SDF1α gradient scaffolds can potentially be employed for guided nerve regeneration.

  7. Electrospun poly(L-lactide-co-acryloyl carbonate) fiber scaffolds with a mechanically stable crimp structure for ligament tissue engineering.

    PubMed

    Chen, Fei; Hayami, James W S; Amsden, Brian G

    2014-05-12

    The aim of this study was to prepare a fibrous scaffold that possesses a crimped morphology using a photo-cross-linkable biodegradable copolymer. To obtain the crimped morphology, the polymer was first electrospun onto a rotating wire mandrel to obtain aligned straight fibers. Postprocessing by immersion in aqueous buffer at 37 °C generated a crimplike pattern in the fibers. It was reasoned that cross-linking the fibers following formation of the crimped structure would endow the scaffolds with a recoverable crimp pattern and mechanical properties similar to that of the collagen fibers in the anterior cruciate ligament (ACL). To achieve this aim, a trimethylene carbonate based monomer bearing an acrylate pendant group was synthesized and copolymerized with l-lactide. The copolymer was electrospun and photo-cross-linked yielding fibrous scaffolds possessing a substantial increase in tensile modulus and crimp stability compared to the uncross-linked fibrous scaffolds. The crimp-stabilized scaffolds also showed good cytocompatibility toward 3T3 fibroblasts, which attached and grew along the crimped fibers. These findings suggest that these cross-linked fiber scaffolds may be useful for the generation of cultured ligament tissue. PMID:24697661

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

    NASA Astrophysics Data System (ADS)

    Laforgue, Alexis

    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 -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.

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

    PubMed

    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.

  10. Modeling of process-induced residual stresses and resin flow behavior in resin transfer molded composites with woven fiber mats

    NASA Astrophysics Data System (ADS)

    Golestanian, Hossein

    This research focuses on modeling Resin Transfer Molding process for manufacture of composite parts with woven fiber mats. Models are developed to determine cure dependent stiffness matrices for composites manufactured with two types of woven fiber mats. Five-harness carbon and eight-harness fiberglass mats with EPON 826 resin composites are considered. The models presented here take into account important material/process parameters with emphasis on; (1) The effects of cure-dependent resin mechanical properties, (2) Fiber undulation due to the weave of the fiber fill and warp bundles, and (3) Resin interaction with the fiber bundles at a microscopic scale. Cure-dependent mechanical properties were then used in numerical models to determine residual stresses and deformation in the composite parts. The complete cure cycle was modeled in these analyses. Also the cool down stage after the composite cure was analyzed. The effect of 5% resin shrinkage on residual stresses and deformations was also investigated. In the second part of the study, Finite Element models were developed to simulate mold filling in RTM processes. Resin flow in the fiber mats was modeled as flow through porous media. Physical models were also developed to investigate resin flow behavior into molds of rectangular and irregular shapes. Silicone fluids of 50 and 100 centistoke viscosities as well as EPON 826 epoxy resin were used in the mold filling experiments. The reinforcements consisted of several layers of woven fiberglass and carbon fiber mats. The effects of injection pressure, fluid viscosity, type of reinforcement, and mold geometry on mold filling times were investigated. Fiber mat permeabilities were determined experimentally for both types of reinforcements. Comparison of experimental and numerical resin front positions indicated the importance of edge effects in resin flow behavior in small cavities. The resin front positions agreed well for the rectangular mold geometry.

  11. Tough and transparent nylon-6 electrospun nanofiber reinforced melamine-formaldehyde composites.

    PubMed

    Jiang, Shaohua; Hou, Haoqing; Greiner, Andreas; Agarwal, Seema

    2012-05-01

    The use of nylon-6 electrospun nanofiber mats as reinforcement with synergistic effect in tensile strength and toughness for melamine-formaldehyde (MF) resin is highlighted in this article. Interestingly, there was a drastic effect of the wetting procedure of reinforcing fiber mat by the MF resin on the morphology and mechanical properties of the composites. The wetting of nylon fibers by passing through a solution of MF resin showed a core-shell morphology and a significant improvement in properties as compared to the dip-coating procedure for wetting of the fibers. Depending on the wt% of reinforcing nylon fiber mats, the composites could be considered as either fiber reinforced MF composites or MF glued nylon fibers.

  12. Towards a novel bioelectrocatalytic platform based on “wiring” of pyrroloquinoline quinone-dependent glucose dehydrogenase with an electrospun conductive polymeric fiber architecture

    NASA Astrophysics Data System (ADS)

    Gladisch, Johannes; Sarauli, David; Schäfer, Daniel; Dietzel, Birgit; Schulz, Burkhard; Lisdat, Fred

    2016-01-01

    Electrospinning is known as a fabrication technique for electrode architectures that serve as immobilization matrices for biomolecules. The current work demonstrates a novel approach to construct a conductive polymeric platform, capable not only of immobilization, but also of electrical connection of the biomolecule with the electrode. It is produced upon electrospinning from mixtures of three different highly conductive sulfonated polyanilines and polyacrylonitrile on ITO electrodes. The resulting fiber mats are with a well-retained conductivity. After coupling the enzyme pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH) to polymeric structures and addition of the substrate glucose an efficient bioelectrocatalysis is demonstrated. Depending on the choice of the sulfonated polyanilline mediatorless bioelectrocatalysis starts at low potentials; no large overpotential is needed to drive the reaction. Thus, the electrospun conductive immobilization matrix acts here as a transducing element, representing a promising strategy to use 3D polymeric scaffolds as wiring agents for active enzymes. In addition, the mild and well reproducible fabrication process and the active role of the polymer film in withdrawing electrons from the reduced PQQ-GDH lead to a system with high stability. This could provide access to a larger group of enzymes for bioelectrochemical applications including biosensors and biofuel cells.

  13. Towards a novel bioelectrocatalytic platform based on "wiring" of pyrroloquinoline quinone-dependent glucose dehydrogenase with an electrospun conductive polymeric fiber architecture.

    PubMed

    Gladisch, Johannes; Sarauli, David; Schäfer, Daniel; Dietzel, Birgit; Schulz, Burkhard; Lisdat, Fred

    2016-01-01

    Electrospinning is known as a fabrication technique for electrode architectures that serve as immobilization matrices for biomolecules. The current work demonstrates a novel approach to construct a conductive polymeric platform, capable not only of immobilization, but also of electrical connection of the biomolecule with the electrode. It is produced upon electrospinning from mixtures of three different highly conductive sulfonated polyanilines and polyacrylonitrile on ITO electrodes. The resulting fiber mats are with a well-retained conductivity. After coupling the enzyme pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH) to polymeric structures and addition of the substrate glucose an efficient bioelectrocatalysis is demonstrated. Depending on the choice of the sulfonated polyanilline mediatorless bioelectrocatalysis starts at low potentials; no large overpotential is needed to drive the reaction. Thus, the electrospun conductive immobilization matrix acts here as a transducing element, representing a promising strategy to use 3D polymeric scaffolds as wiring agents for active enzymes. In addition, the mild and well reproducible fabrication process and the active role of the polymer film in withdrawing electrons from the reduced PQQ-GDH lead to a system with high stability. This could provide access to a larger group of enzymes for bioelectrochemical applications including biosensors and biofuel cells. PMID:26822141

  14. Towards a novel bioelectrocatalytic platform based on “wiring” of pyrroloquinoline quinone-dependent glucose dehydrogenase with an electrospun conductive polymeric fiber architecture

    PubMed Central

    Gladisch, Johannes; Sarauli, David; Schäfer, Daniel; Dietzel, Birgit; Schulz, Burkhard; Lisdat, Fred

    2016-01-01

    Electrospinning is known as a fabrication technique for electrode architectures that serve as immobilization matrices for biomolecules. The current work demonstrates a novel approach to construct a conductive polymeric platform, capable not only of immobilization, but also of electrical connection of the biomolecule with the electrode. It is produced upon electrospinning from mixtures of three different highly conductive sulfonated polyanilines and polyacrylonitrile on ITO electrodes. The resulting fiber mats are with a well-retained conductivity. After coupling the enzyme pyrroloquinoline quinone-dependent glucose dehydrogenase (PQQ-GDH) to polymeric structures and addition of the substrate glucose an efficient bioelectrocatalysis is demonstrated. Depending on the choice of the sulfonated polyanilline mediatorless bioelectrocatalysis starts at low potentials; no large overpotential is needed to drive the reaction. Thus, the electrospun conductive immobilization matrix acts here as a transducing element, representing a promising strategy to use 3D polymeric scaffolds as wiring agents for active enzymes. In addition, the mild and well reproducible fabrication process and the active role of the polymer film in withdrawing electrons from the reduced PQQ-GDH lead to a system with high stability. This could provide access to a larger group of enzymes for bioelectrochemical applications including biosensors and biofuel cells. PMID:26822141

  15. A simple method for fabrication of electrospun fibers with controlled degree of alignment having potential for nerve regeneration applications.

    PubMed

    Vimal, Sunil Kumar; Ahamad, Nadim; Katti, Dhirendra S

    2016-06-01

    In peripheral nerve injuries where direct suturing of nerve endings is not feasible, nerve regeneration has been facilitated through the use of artificially aligned fibrous scaffolds that provide directional growth of neurons to bridge the gap. The degree of fiber alignment is crucial and can impact the directionality of cells in a fibrous scaffold. While there have been multiple approaches that have been used for controlling fiber alignment, however, they have been associated with a compromised control on other properties, such as diameter, morphology, curvature, and topology of fibers. Therefore, the present study demonstrates a modified electrospinning set-up, that enabled fabrication of electrospun fibers with controlled degree of alignment from non-aligned (NA), moderately aligned (MA, 75%) to highly aligned (HA, 95%) sub-micron fibers while keeping other physical properties unchanged. The results demonstrate that the aligned fibers (MA and HA) facilitated directional growth of human astrocytoma cells (U373), wherein the aspect ratio of cells was found to increase with an increase in degree of fibers alignment. In contrast to NA and MA fibers, the HA fibers showed improved contact guidance to U373 cells that was demonstrated by a significantly higher cell aspect ratio and nuclear aspect ratio. In conclusion, the present study demonstrated a modified electrospinning setup to fabricate differentially aligned fibrous scaffolds with the HA fibers showing potential for use in neural tissue engineering.

  16. Anisotropic Poly (glycerol sebacate)-Poly (ε-caprolactone) Electrospun Fibers Promote Endothelial Cell Guidance

    PubMed Central

    Gaharwar, Akhilesh K.; Nikkhah, Mehdi; Sant, Shilpa; Khademhosseini, Ali

    2015-01-01

    Topographical cell guidance is utilized to engineer highly organized and aligned cellular constructs for numerous tissue engineering applications. Recently, electrospun scaffolds fabricated using poly(glycerol sebacate) (PGS) and poly(ε-caprolactone) (PCL) have shown a great promise to support valvular interstitial cell functions for the development of tissue engineered heart valves. However, one of the major drawbacks of PGS-PCL scaffolds is the lack of control over cellular alignment. In this work we investigate the role of scaffold architecture on the endothelial cell alignment, proliferation and formation of organized cellular structures. In particular, PGS-PCL scaffolds with randomly oriented and highly aligned fibers with tunable mechanical properties were fabricated using electrospinning technique. After one week of culture, endothelial cells on the aligned scaffolds exhibit higher proliferation compared to those cultures on randomly oriented fibrous scaffolds. Furthermore, the endothelial cells reorganize in response to the topographical features of anisotropic scaffolds forming highly organize cellular constructs. Thus, the topographical contact guidance, provided by aligned PGS-PCL scaffolds, is envisioned to be useful in developing aligned cellular structures for vascular tissue engineering. PMID:25516556

  17. 3D cell culture and osteogenic differentiation of human bone marrow stromal cells plated onto jet-sprayed or electrospun micro-fiber scaffolds.

    PubMed

    Brennan, Meadhbh Á; Renaud, Audrey; Gamblin, Anne-Laure; D'Arros, Cyril; Nedellec, Steven; Trichet, Valerie; Layrolle, Pierre

    2015-08-01

    A major limitation of the 2D culture systems is that they fail to recapitulate the in vivo 3D cellular microenvironment whereby cell-cell and cell-extracellular matrix (ECM) interactions occur. In this paper, a biomaterial scaffold that mimics the structure of collagen fibers was produced by jet-spraying. This micro-fiber polycaprolactone (PCL) scaffold was evaluated for 3D culture of human bone marrow mesenchymal stromal cells (MSCs) in comparison with a commercially available electrospun scaffold. The jet-sprayed scaffolds had larger pore diameters, greater porosity, smaller diameter fibers, and more heterogeneous fiber diameter size distribution compared to the electrospun scaffolds. Cells on jet-sprayed constructs exhibited spread morphology with abundant cytoskeleton staining, whereas MSCs on electrospun scaffolds appeared less extended with fewer actin filaments. MSC proliferation and cell infiltration occurred at a faster rate on jet-sprayed compared to electrospun scaffolds. Osteogenic differentiation of MSCs and ECM production as measured by ALP, collagen and calcium deposition was superior on jet-sprayed compared to electrospun scaffolds. The jet-sprayed scaffold which mimics the native ECM and permits homogeneous cell infiltration is important for 3D in vitro applications such as bone cellular interaction studies or drug testing, as well as bone tissue engineering strategies. PMID:26238732

  18. Functionalized electrospun nanofibers as bioseparators in microfluidic systems.

    PubMed

    Matlock-Colangelo, Lauren; Cho, Daehwan; Pitner, Christine L; Frey, Margaret W; Baeumner, Antje J

    2012-05-01

    Functionalized electrospun nanofibers were integrated into microfluidic channels to serve as on-chip bioseparators. Specifically, poly(vinyl alcohol) (PVA) nanofiber mats were shown to successfully serve as bioseparators for negatively charged nanoparticles. Nanofibers were electrospun onto gold microelectrodes, which were incorporated into poly(methyl methacrylate) (PMMA) microfluidic devices using UV-assisted thermal bonding. PVA nanofibers functionalized with poly(hexadimethrine bromide) (polybrene) were positively charged and successfully filtered negatively charged liposomes out of a buffer solution, while negatively charged nanofibers functionalized with Poly(methyl vinyl ether-alt-maleic anhydride) (POLY(MVE/MA)) were shown to repel the liposomes. The effect of fiber mat thickness was studied using confocal fluorescence microscopy, determining a quite broad optimal range of thicknesses for specific liposome retention, which simplifies fiber mat production with respect to retention reliability. Finally, it was demonstrated that liposomes bound to positively charged nanofibers could be selectively released using a 4-(2-Hydroxyethyl)piperazine-1-ethanesulfonic acid (HEPES)-sucrose-saline (HSS) solution of pH 9, which dramatically changes the nanofiber zeta potential and renders the positively charged nanofibers negatively charged. This is the first demonstration of functional electrospun nanofibers used to enable sample preparation procedures of isolation and concentration in lab-on-a-chip devices. This has far reaching impact on the ability to integrate functional surfaces and materials into microfluidic devices and to significantly expand their ability toward simple lab-on-a-chip devices.

  19. Flexible N-doped TiO2/C ultrafine fiber mat and its photocatalytic activity under simulated sunlight

    NASA Astrophysics Data System (ADS)

    Wu, Nan; Wang, Yingde; Lei, Yongpeng; Wang, Bing; Han, Cheng

    2014-11-01

    Flexible N-doped TiO2/C ultrafine fiber (NTCf) mat has been produced via electrospinning and subsequent heat treatment, analyzed by a combination of characterizations. The nitrogen content can be modulated by the addition of urea. The composite fiber with mean diameter of around 500 nm exhibits outstanding mechanical flexibility. The TiO2 in the fiber obtained at 700 °C is anatase with a mass ratio of 23 wt%. In the photodegradation experiment under simulated sunlight, the as-prepared flexible mat demonstrates remarkable efficiency in the degradation of methylene blue (MB) due to the well-proportioned distribution of TiO2 nanoparticles and the improvement of charge transfer process. The nitrogen species in TiO2 lattice and the nitrogen functional groups on the surface of the fiber play crucial impacts on the photocatalytic activity.

  20. Highly Porous Regenerated Cellulose Fiber Mats via the Co-Forcespinning of Cellulose Acetate for Separator Applications

    NASA Astrophysics Data System (ADS)

    Castillo, Alejandro; Mao, Yuanbing

    2015-03-01

    Improvements in battery technology are necessary for the transition away from a fossil fuel based economy. An important bottle-neck in battery efficiency is the quality of the separator, which separates the cathode and anode to prevent a short-circuit while still allowing the ions in solution to flow as close to unabated as possible. In this work solutions of cellulose acetate, polyvinyldiflourine (pvdf), and polyvinylpyrrolidone (pvp) dissolved in a 2:1 v/v acetone/dimethylacetamide solvent mixture were Forcespun to create nonwoven fiber mats of nanoscale diameter. These mats were then soaked in a NaOH solution so as to both strip the pvp from the fiber as well as regenerate cellulose from its acetate derivative for the purpose of creating high surface area, nanoporous, hydrophilic, and ioniclly conductive cellulose/pvdf nonwoven mats for the purposes of testing their suitability as battery separators

  1. Enhanced GLT-1 mediated glutamate uptake and migration of primary astrocytes directed by fibronectin-coated electrospun poly-L-lactic acid fibers

    PubMed Central

    Zuidema, Jonathan M.; Hyzinski-García, María C.; Vlasselaer, Kristien Van; Zaccor, Nicholas; Plopper, George E.; Mongin, Alexander A.; Gilbert, Ryan J.

    2014-01-01

    Bioengineered fiber substrates are increasingly studied as a means to promote regeneration and remodeling in the injured central nervous system (CNS). Previous reports largely focused on the ability of oriented scaffolds to bridge injured regions and direct outgrowth of axonal projections. In the present work, we explored the effects of electrospun microfibers on the migration and physiological properties of brain astroglial cells. Primary rat astrocytes were cultured on either fibronectin-coated poly-l-lactic acid (PLLA) films, fibronectin-coated randomly oriented PLLA electrospun fibers, or fibronectin-coated aligned PLLA electrospun fibers. Aligned PLLA fibers strongly altered astrocytic morphology, orienting cell processes, actin microfilaments, and microtubules along the length of the fibers. On aligned fibers, astrocytes also significantly increased their migration rates in the direction of fiber orientation. We further investigated if fiber topography modifies astrocytic neuroprotective properties, namely glutamate and glutamine transport and metabolism. This was done by quantifying changes in mRNA expression (qRT-PCR) and protein levels (Western blotting) for a battery of relevant biomolecules. Interestingly, we found that cells grown on random and/or aligned fibers increased the expression levels of two glutamate transporters, GLAST and GLT-1, and an important metabolic enzyme, glutamine synthetase, as compared to the fibronectin-coated films. Functional assays revealed increases in glutamate transport rates due to GLT-1 mediated uptake, which was largely determined by the dihydrokainate-sensitive GLT-1. Overall, this study suggests that aligned PLLA fibers can promote directed astrocytic migration, and, of most importance, our in vitro results indicate for the first time that electrospun PLLA fibers can positively modify neuroprotective properties of glial cells by increasing rates of glutamate uptake. PMID:24246642

  2. Design of Electrospun Hydrogel Fibers Containing Multivalent Peptide Conjugates for Cardiac Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Rode, Nikhil Ajit

    A novel material was designed using biomimetic engineering principles to recreate the chemical and physical environment of the extracellular matrix for cardiac tissue engineering applications. In order to control the chemical and specific bioactive signals provided by the material, a multivalent conjugate of a RGD-containing cell-binding peptide with hyaluronic acid was synthesized. These conjugates were characterized using in-line size exclusion chromatography with static multi-angle light scattering, UV absorbance, and differential refractive index measurements (SEC-MALS-UV-RI) to determine their molecular weight and valency, as well as the distributions of each. These conjugates were electrospun with poly(ethylene glycol) and poly(ethylene glycol) diacrylate to create a nanofibrous hydrogel material embedded with bioinstructive macromolecules. This electrospinning process was explored and optimized to create well-formed nanofibers. The diameter and orientation of the fibers was controlled to closely mimic the nanostructure of the extracellular matrix of the myocardium. Further characterization of the material was performed to ensure that its mechanical properties resemble those found in the myocardium. The availability of the peptides embedded in the hydrogel material was confirmed by measuring peptides released by trypsin incubation and was found to be sufficient to cause cell adhesion. This material was capable of supporting cell culture, maintaining the viability of cultured fibroblasts and cardiomyocytes, and preserving cardiomyocyte functionality. In this way, this material shows promise of serving as a biomimetic in vitro scaffold for generation of functional myocardial tissue, with possible applications as an in vivo cardiac patch for repair of the damage myocardium post-myocardial infarction.

  3. Fabrication of nanofiber mats from electrospinning of functionalized polymers

    NASA Astrophysics Data System (ADS)

    Oktay, Burcu; Kayaman-Apohan, Nilhan; Erdem-Kuruca, Serap

    2014-08-01

    Electrospinning technique enabled us to prepare nanofibers from synthetic and natural polymers. In this study, it was aimed to fabricate electrospun poly(vinyl alcohol) (PVA) based nanofibers by reactive electrospinning process. To improve endurance of fiber toward to many solvents, PVA was functionalized with photo-crosslinkable groups before spinning. Afterward PVA was crosslinked by UV radiation during electrospinning process. The nanofiber mats were characterized by scanning electron microscopy (SEM). The results showed that homogenous, uniform and crosslinked PVA nanofibers in diameters of about 200 nm were obtained. Thermal stability of the nanofiber mat was investigated with thermal gravimetric analysis (TGA). Also the potential use of this nanofiber mats for tissue engineering was examined. Osteosarcoma (Saos) cells were cultured on the nanofiber mats.

  4. A silk derived carbon fiber mat modified with Au@Pt urchilike nanoparticles: A new platform as electrochemical microbial biosensor.

    PubMed

    Deng, Liu; Guo, Shaojun; Zhou, Ming; Liu, Ling; Liu, Chang; Dong, Shaojun

    2010-06-15

    We present here a facile and efficient route to prepare silk derived carbon mat modified with Au@Pt urchilike nanoparticles (Au@Pt NPs) and develop an Escherichia coli (E. coli)-based electrochemical sensor using this material. Silk is a natural protein fiber, and it is abundant with kinds of functionalities which are important in the development of the derived material. The S-derived carbon fiber mat have amino, pyridine and carbonyl functional groups, these natural existent functionalities allow the Au@Pt NPs to self-assemble on the carbon fiber surface and provide a biocompatible microenvironment for bacteria. The Au@Pt NPs modified S-derived carbon fiber is sensitive to detect the E. coli activities with a low detection limit, where glucose is used as a prelimiltary substrate to evaluate them. The performance of Au@Pt/carbon fiber mat based biosensor is much better than that of commercial carbon paper based biosensor. The high sensitivity of this biosensor stems from the unique electrocatalytic properties of Au@Pt urchilike NPs and quinone groups presented in S-derived carbon fiber. This biosensor is also tested for detection of organophosphate pesticides, fenamiphos. The relative inhibition of E. coli activity is linear with -log[fenamiphos] at the concentration range from 0.5mg/L to 36.6 mg/L with lowest observable effect concentration (LOEC) of 0.09 mg/L. The Au@Pt NPs modified S-derived carbon fiber mat possesses high conductivity, biocompatibility and high electrocatalytic activity and be can used as advanced electrode materials for microbial biosensor improvement. The microbial biosensor based on this material shows potential applications in environmental monitoring.

  5. Free-standing and mechanically flexible mats consisting of electrospun carbon nanofibers made from a natural product of alkali lignin as binder-free electrodes for high-performance supercapacitors

    NASA Astrophysics Data System (ADS)

    Lai, Chuilin; Zhou, Zhengping; Zhang, Lifeng; Wang, Xiaoxu; Zhou, Qixin; Zhao, Yong; Wang, Yechun; Wu, Xiang-Fa; Zhu, Zhengtao; Fong, Hao

    2014-02-01

    Mechanically flexible mats consisting of electrospun carbon nanofibers (ECNFs) were prepared by first electrospinning aqueous mixtures containing a natural product of alkali lignin together with polyvinyl alcohol (PVA) into composite nanofiber mats followed by stabilization in air and carbonization in an inert environment. Morphological and structural properties, as well as specific surface area, total pore volume, average pore size, and pore size distribution, of the lignin-based ECNF mats were characterized; and their electrochemical performances (i.e., capacitive behaviors) were evaluated by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. The lignin-based ECNF mats exhibited outstanding performance as free-standing and/or binder-free electrodes of supercapacitors. For example, the ECNFs made from the composite nanofibers with mass ratio of lignin/PVA being 70/30 (i.e., ECNFs (70/30)) had the average diameter of ∼100 nm and the Brunauer-Emmett-Teller (BET) specific surface area of ∼583 m2 g-1. The gravimetric capacitance of ECNFs (70/30) electrode in 6 M KOH aqueous electrolyte exhibited 64 F g-1 at current density of 400 mA g-1 and 50 F g-1 at 2000 mA g-1. The ECNFs (70/30) electrode also exhibited excellent cycling durability/stability, and the gravimetric capacitance merely reduced by ∼10% after 6000 cycles of charge/discharge.

  6. Modification of poly(L-lactic acid) electrospun fibers and films with poly(propylene imine) dendrimer

    NASA Astrophysics Data System (ADS)

    Khaliliazar, Sh.; Akbari, S.; Kish, M. H.

    2016-02-01

    Poly(L-lactic acid) (PLLA) electrospun fibers and films were modified with the second generation of poly(propylene imine) dendrimer (PPI-G2) by three different approaches, namely, sodium hydroxide hydrolysis, plasma treatment and direct application of PPI-G2. For the first and the second approaches, PLLA was modified by sodium hydroxide hydrolysis or plasma treatment to produce carboxylic acid groups. Then, the carboxylic acid groups were activated by 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) and N,N‧-dicyclohexyl carbodiimide (DCC) as a hetero bi-functional cross-linker. The cross-linkers promoted the grafting of carboxylic acid groups on the modified PLLA with NH2 groups of PPI-G2. In the third approach, the PPI-G2 dendrimer was directly used as an aminolysis agent for the functionalization of PLLA in a one step process. FTIR analysis confirmed the presence of sbnd NH2 groups of PPI-G2 on the modified PLLA samples, resulting from each one of the three modification methods. Studies by SEM shows bead free electrospun fibers. Also, FE-SEM shows nano-cracks on the surface of films after modification. Contact angle, drug release tests, antibacterial effects and the dying results confirmed that these functionalization methods increased hydrophilicity and reactive side-chains of PLLA in the wet chemical process resulted in providing host-guest properties on the PLLA surface for adsorbing various kinds of guest molecules.

  7. Polydopamine Inter-Fiber Networks: New Strategy for Producing Rigid, Sticky, 3D Fluffy Electrospun Fibrous Polycaprolactone Sponges.

    PubMed

    Choi, Wuyong; Lee, Slgirim; Kim, Seung-Hyun; Jang, Jae-Hyung

    2016-06-01

    Designing versatile 3D interfaces that can precisely represent a biological environment is a prerequisite for the creation of artificial tissue structures. To this end, electrospun fibrous sponges, precisely mimicking an extracellular matrix and providing highly porous interfaces, have capabilities that can function as versatile physical cues to regenerate various tissues. However, their intrinsic features, such as sheet-like, thin, and weak structures, limit the design of a number of uses in tissue engineering applications. Herein, a highly facile methodology capable of fabricating rigid, sticky, spatially expanded fluffy electrospun fibrous sponges is proposed. A bio-inspired adhesive material, poly(dopamine) (pDA), is employed as a key mediator to provide rigidity and stickiness to the 3D poly(ε-caprolactone) (PCL) fibrous sponges, which are fabricated using a coaxial electrospinning with polystyrene followed by a selective leaching process. The iron ion induced oxidation of dopamine into pDA networks interwoven with PCL fibers results in significant increases in the rigidity of 3D fibrous sponges. Furthermore, the exposure of catecholamine groups on the fiber surfaces promotes the stable attachment of the sponges on wet organ surfaces and triggers the robust immobilization of biomolecules (e.g., proteins and gene vectors), demonstrating their potential for 3D scaffolds as well as drug delivery vehicles. Because fibrous structures are ubiquitous in the human body, these rigid, sticky, 3D fibrous sponges are good candidates for powerful biomaterial systems that functionally mimic a variety of tissue structures.

  8. Quantitative imaging of electrospun fibers by PeakForce Quantitative NanoMechanics atomic force microscopy using etched scanning probes.

    PubMed

    Chlanda, Adrian; Rebis, Janusz; Kijeńska, Ewa; Wozniak, Michal J; Rozniatowski, Krzysztof; Swieszkowski, Wojciech; Kurzydlowski, Krzysztof J

    2015-05-01

    Electrospun polymeric submicron and nanofibers can be used as tissue engineering scaffolds in regenerative medicine. In physiological conditions fibers are subjected to stresses and strains from the surrounding biological environment. Such stresses can cause permanent deformation or even failure to their structure. Therefore, there is a growing necessity to characterize their mechanical properties, especially at the nanoscale. Atomic force microscopy is a powerful tool for the visualization and probing of selected mechanical properties of materials in biomedical sciences. Image resolution of atomic force microscopy techniques depends on the equipment quality and shape of the scanning probe. The probe radius and aspect ratio has huge impact on the quality of measurement. In the presented work the nanomechanical properties of four different polymer based electrospun fibers were tested using PeakForce Quantitative NanoMechanics atomic force microscopy, with standard and modified scanning probes. Standard, commercially available probes have been modified by etching using focused ion beam (FIB). Results have shown that modified probes can be used for mechanical properties mapping of biomaterial in the nanoscale, and generate nanomechanical information where conventional tips fail.

  9. Electrospun cellulose acetate nanofibers: the present status and gamut of biotechnological applications.

    PubMed

    Konwarh, Rocktotpal; Karak, Niranjan; Misra, Manjusri

    2013-01-01

    Cellulose acetate (CA) has been a material of choice for spectrum of utilities across different domains ranging from high absorbing diapers to membrane filters. Electrospinning has conferred a whole new perspective to polymeric materials including CA in the context of multifarious applications across myriad of niches. In the present review, we try to bring out the recent trend (focused over last five years' progress) of research on electrospun CA fibers of nanoscale regime in the context of developmental strategies of their blends and nanocomposites for advanced applications. In the realm of biotechnology, electrospun CA fibers have found applications in biomolecule immobilization, tissue engineering, bio-sensing, nutraceutical delivery, bioseparation, crop protection, bioremediation and in the development of anti-counterfeiting and pH sensitive material, photocatalytic self-cleaning textile, temperature-adaptable fabric, and antimicrobial mats, amongst others. The present review discusses these diverse applications of electrospun CA nanofibers. PMID:23318668

  10. The formation of web-like connection among electrospun chitosan/PVA fiber network by the reinforcement of ellipsoidal calcium carbonate.

    PubMed

    Sambudi, Nonni Soraya; Kim, Minjeong G; Park, Seung Bin

    2016-03-01

    The electrospun fibers consist of backbone fibers and nano-branch network are synthesized by loading of ellipsoidal calcium carbonate in the mixture of chitosan/poly(vinyl alcohol) (PVA) followed by electrospinning. The synthesized ellipsoidal calcium carbonate is in submicron size (730.7±152.4 nm for long axis and 212.6±51.3 nm for short axis). The electrospun backbone fibers experience an increasing in diameter by loading of calcium carbonate from 71.5±23.4 nm to 281.9±51.2 nm. The diameters of branch fibers in the web-network range from 15 nm to 65 nm with most distributions of fibers are in 30-35 nm. Calcium carbonate acts as reinforcing agent to improve the mechanical properties of fibers. The optimum value of Young's modulus is found at the incorporation of 3 wt.% of calcium carbonate in chitosan/PVA fibers, which is enhanced from 15.7±3 MPa to 432.4±94.3 MPa. On the other hand, the ultimate stress of fibers experiences a decrease. This result shows that the fiber network undergoes changes from flexible to more stiff by the inclusion of calcium carbonate. The thermal analysis results show that the crystallinity of polymer is changed by the existence of calcium carbonate in the fiber network. The immersion of fibers in simulated body fluid (SBF) results in the formation of apatite on the surface of fibers.

  11. The formation of web-like connection among electrospun chitosan/PVA fiber network by the reinforcement of ellipsoidal calcium carbonate.

    PubMed

    Sambudi, Nonni Soraya; Kim, Minjeong G; Park, Seung Bin

    2016-03-01

    The electrospun fibers consist of backbone fibers and nano-branch network are synthesized by loading of ellipsoidal calcium carbonate in the mixture of chitosan/poly(vinyl alcohol) (PVA) followed by electrospinning. The synthesized ellipsoidal calcium carbonate is in submicron size (730.7±152.4 nm for long axis and 212.6±51.3 nm for short axis). The electrospun backbone fibers experience an increasing in diameter by loading of calcium carbonate from 71.5±23.4 nm to 281.9±51.2 nm. The diameters of branch fibers in the web-network range from 15 nm to 65 nm with most distributions of fibers are in 30-35 nm. Calcium carbonate acts as reinforcing agent to improve the mechanical properties of fibers. The optimum value of Young's modulus is found at the incorporation of 3 wt.% of calcium carbonate in chitosan/PVA fibers, which is enhanced from 15.7±3 MPa to 432.4±94.3 MPa. On the other hand, the ultimate stress of fibers experiences a decrease. This result shows that the fiber network undergoes changes from flexible to more stiff by the inclusion of calcium carbonate. The thermal analysis results show that the crystallinity of polymer is changed by the existence of calcium carbonate in the fiber network. The immersion of fibers in simulated body fluid (SBF) results in the formation of apatite on the surface of fibers. PMID:26706559

  12. Two Different Approaches for Oral Administration of Voriconazole Loaded Formulations: Electrospun Fibers versus β-Cyclodextrin Complexes

    PubMed Central

    Siafaka, Panoraia I.; Üstündağ Okur, Neslihan; Mone, Mariza; Giannakopoulou, Spyridoula; Er, Sevda; Pavlidou, Eleni; Karavas, Evangelos; Bikiaris, Dimitrios N.

    2016-01-01

    In this work, a comparison between two different preparation methods for the improvement of dissolution rate of an antifungal agent is presented. Poly(ε-caprolactone) (PCL) electrospun fibers and β-cyclodextrin (β-CD) complexes, which were produced via an electrospinning process and an inclusion complexation method, respectively, were addressed for the treatment of fungal infections. Voriconazole (VRCZ) drug was selected as a model drug. PCL nanofibers were characterized on the basis of morphology while phase solubility studies for β-CDs complexes were performed. Various concentrations (5, 10, 15 and 20 wt %) of VRCZ were loaded to PCL fibers and β-CD inclusions to study the in vitro release profile as well as in vitro antifungal activity. The results clearly indicated that all formulations showed an improved VRCZ solubility and can inhibit fungi proliferation. PMID:26927072

  13. Preparation and characterization of coaxial electrospun thermoplastic polyurethane/collagen compound nanofibers for tissue engineering applications.

    PubMed

    Chen, Rui; Huang, Chen; Ke, Qinfei; He, Chuanglong; Wang, Hongsheng; Mo, Xiumei

    2010-09-01

    Collagen functionalized thermoplastic polyurethane nanofibers (TPU/collagen) were successfully produced by coaxial electrospinning technique with a goal to develop biomedical scaffold. A series of tests were conducted to characterize the compound nanofiber and its membrane in this study. Surface morphology and interior structure of the ultrafine fibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM), whereas the fiber diameter distribution was also measured. The crosslinked membranes were also characterized by SEM. Porosities of different kinds of electrospun mats were determined. The surface chemistry and chemical composition of collagen/TPU coaxial nanofibrous membranes were verified by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrometry (FTIR). Mechanical measurements were carried out by applying tensile test loads to samples which were prepared from electrospun ultra fine non-woven fiber mats. The coaxial electrospun nanofibers were further investigated as a promising scaffold for PIECs culture. The results demonstrated that coaxial electrospun composite nanofibers had the characters of native extracellular matrix and may be used effectively as an alternative material for tissue engineering and functional biomaterials. PMID:20471809

  14. Guidance of in vitro migration of human mesenchymal stem cells and in vivo guided bone regeneration using aligned electrospun fibers.

    PubMed

    Lee, Ji-hye; Lee, Young Jun; Cho, Hyeong-jin; Shin, Heungsoo

    2014-08-01

    Tissue regeneration is a complex process in which numerous chemical and physical signals are coordinated in a specific spatiotemporal pattern. In this study, we tested our hypothesis that cell migration and bone tissue formation can be guided and facilitated by microscale morphological cues presented from a scaffold. We prepared poly(l-lactic acid) (PLLA) electrospun fibers with random and aligned structures and investigated their effect on in vitro migration of human mesenchymal stem cells (hMSCs) and in vivo bone growth using a critical-sized defect model. Using a polydopamine coating on the fibers, we compared the synergistic effects of chemical signals. The adhesion morphology of hMSCs was consistent with the direction of fiber alignment, whereas the proliferation of hMSCs was not affected. The orientation of fibers profoundly affected cell migration, in which hMSCs cultured on aligned fibers migrated 10.46-fold faster along the parallel direction than along the perpendicular direction on polydopamine-coated PLLA nanofibers. We implanted each fiber type into a mouse calvarial defect model for 2 months. The micro-computed tomography (CT) imaging demonstrated that regenerated bone area was the highest when mice were implanted with aligned fibers with polydopamine coating, indicating a positive synergistic effect on bone regeneration. More importantly, scanning electron microscopy microphotographs revealed that the direction of regenerated bone tissue appeared to be consistent with the direction of the implanted fibers, and transmission electron microscopy images showed that the orientation of collagen fibrils appeared to be overlapped along the direction of nanofibers. Taken together, our results demonstrate that the aligned nanofibers can provide spatial guidance for in vitro cell migration as well as in vivo bone regeneration, which may be incorporated as major instructive cues for the stimulation of tissue regeneration.

  15. Effect of Relative Humidity on the Morphology of Electrospun Polymer Fibers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effect of relative humidity on the morphology of electrospun nanofibers of poly(vinyl alcohol), poly(methyl metacrylate), poly(vinyl chloride), polystyrene, and poly(lactic acid) dissolved in solvents such as toluene and N,N-dimethylformamide, 2,2,2-trifluoroethanol and deionized water was studi...

  16. Improving cytoactive of endothelial cell by introducing fibronectin to the surface of poly L-Lactic acid fiber mats via dopamine.

    PubMed

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

    2016-12-01

    A simple but straightforward approach was reported to prepare fiber mats modified with fibronectin (Fn) protein for endothelial cells activity study. Based on the self-polymerization and strong adhesion feature of dopamine, poly L-Lactic acid (PLLA) fibers mat was modified via simply immersing them into dopamine solution for 16h. Subsequently, Fn was immobilized onto the fiber mats surface by the coupling reactive polydopamine (PDA) layer and Fn. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to determine the chemical compositions of fiber mats surface, which confirmed the successful immobilization of PDA and Fn molecules on the fiber surface. Scanning electronic microscopy (SEM) was used to observe the surface morphology changes after modification with PDA and Fn. The data of water contact angle showed that the hydrophilicity of the fiber mats was improved after surface modification. The data of in vitro cell culture proved that the PDA and Fn modified surface significantly enhanced the adhesion, proliferation and cell activity of endothelial cells on the fiber mats. And the release of tumor necrosis factor-α (TNF-α) by endothelial cells on the modified surface was suppressed compared to that on culture plate and PLLA film at 2 and 4days, while the secretion of interleukin-1β (IL-1β) was increased compared to that on culture plate and PLLA film at 2days. PMID:27612725

  17. Improving cytoactive of endothelial cell by introducing fibronectin to the surface of poly L-Lactic acid fiber mats via dopamine.

    PubMed

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

    2016-12-01

    A simple but straightforward approach was reported to prepare fiber mats modified with fibronectin (Fn) protein for endothelial cells activity study. Based on the self-polymerization and strong adhesion feature of dopamine, poly L-Lactic acid (PLLA) fibers mat was modified via simply immersing them into dopamine solution for 16h. Subsequently, Fn was immobilized onto the fiber mats surface by the coupling reactive polydopamine (PDA) layer and Fn. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) were used to determine the chemical compositions of fiber mats surface, which confirmed the successful immobilization of PDA and Fn molecules on the fiber surface. Scanning electronic microscopy (SEM) was used to observe the surface morphology changes after modification with PDA and Fn. The data of water contact angle showed that the hydrophilicity of the fiber mats was improved after surface modification. The data of in vitro cell culture proved that the PDA and Fn modified surface significantly enhanced the adhesion, proliferation and cell activity of endothelial cells on the fiber mats. And the release of tumor necrosis factor-α (TNF-α) by endothelial cells on the modified surface was suppressed compared to that on culture plate and PLLA film at 2 and 4days, while the secretion of interleukin-1β (IL-1β) was increased compared to that on culture plate and PLLA film at 2days.

  18. Method to form a fiber/growth factor dual-gradient along electrospun silk for nerve regeneration.

    PubMed

    Dinis, Tony M; Elia, Roberto; Vidal, Guillaume; Auffret, Adrien; Kaplan, David L; Egles, Christophe

    2014-10-01

    Concentration gradients of guidance molecules influence cell behavior and growth in biological tissues and are therefore of interest for the design of biomedical scaffolds for regenerative medicine. We developed an electrospining method to generate a dual-gradient of bioactive molecules and fiber density along electrospun nanofibers without any post spinning treatment. Functionalization with fluorescent molecules demonstrated the efficiency of the method to generate a discontinuous concentration gradient along the aligned fibers. As a proof of concept for tissue engineering, the silk nanofibers were functionalized with increasing concentrations of nerve growth factor (NGF) and the biological activity was assessed and quantified with rat dorsal root ganglion (DRG) neurons cultures. Protein assays showed the absence of passive release of NGF from the functionalized fibers. The results demonstrated that the NGF concentration gradient led to an oriented and increased growth of DRG neurons (417.6 ± 55.7 μm) compared to a single uniform NGF concentration (264.5 ± 37.6 μm). The easy-to-use electrospinning technique combined with the multiple molecules that can be used for fiber functionalization makes this technique versatile for a broad range of applications from biosensors to regenerative medicine.

  19. Bioactive electrospun fibers of poly(glycerol sebacate) and poly(ε-caprolactone) for cardiac patch application.

    PubMed

    Rai, Ranjana; Tallawi, Marwa; Frati, Caterina; Falco, Angela; Gervasi, Andrea; Quaini, Federico; Roether, Judith A; Hochburger, Tobias; Schubert, Dirk W; Seik, Lothar; Barbani, Niccoletta; Lazzeri, Luigi; Rosellini, Elisabetta; Boccaccini, Aldo R

    2015-09-16

    Scaffolds for cardiac patch application must meet stringent requirements such as biocompatibility, biodegradability, and facilitate vascularization in the engineered tissue. Here, a bioactive, biocompatible, and biodegradable electrospun scaffold of poly(glycerol sebacate)-poly(ε-caprolactone) (PGS-PCL) is proposed as a potential scaffold for cardiac patch application. The fibers are smooth bead free with average diameter = 0.8 ± 0.3 μm, mean pore size = 2.2 ± 1.2 μm, porosity = 62 ± 4%, and permeability higher than that of control biological tissue. For the first time, bioactive PGS-PCL fibers functionalized with vascular endothelial growth factor (VEGF) are developed, the approach used being chemical modification of the PGS-PCL fibers followed by subsequent binding of VEGF via amide bonding. The approach results in uniform immobilization of VEGF on the fibers; the concentrations are 1.0 μg cm(-2) for the PGS-PCL (H) and 0.60 μg cm(-2) for the PGS-PCL (L) samples. The bioactive scaffold supports the attachment and growth of seeded myogenic and vasculogenic cell lines. In fact, rat aortic endothelial cells also display angiogenic features indicating potential for the formation of vascular tree in the scaffold. These results therefore demonstrate the prospects of VEGF-functionalized PGS-PCL fibrous scaffold as promising matrix for cardiac patch application.

  20. Bioactive electrospun fibers of poly(glycerol sebacate) and poly(ε-caprolactone) for cardiac patch application.

    PubMed

    Rai, Ranjana; Tallawi, Marwa; Frati, Caterina; Falco, Angela; Gervasi, Andrea; Quaini, Federico; Roether, Judith A; Hochburger, Tobias; Schubert, Dirk W; Seik, Lothar; Barbani, Niccoletta; Lazzeri, Luigi; Rosellini, Elisabetta; Boccaccini, Aldo R

    2015-09-16

    Scaffolds for cardiac patch application must meet stringent requirements such as biocompatibility, biodegradability, and facilitate vascularization in the engineered tissue. Here, a bioactive, biocompatible, and biodegradable electrospun scaffold of poly(glycerol sebacate)-poly(ε-caprolactone) (PGS-PCL) is proposed as a potential scaffold for cardiac patch application. The fibers are smooth bead free with average diameter = 0.8 ± 0.3 μm, mean pore size = 2.2 ± 1.2 μm, porosity = 62 ± 4%, and permeability higher than that of control biological tissue. For the first time, bioactive PGS-PCL fibers functionalized with vascular endothelial growth factor (VEGF) are developed, the approach used being chemical modification of the PGS-PCL fibers followed by subsequent binding of VEGF via amide bonding. The approach results in uniform immobilization of VEGF on the fibers; the concentrations are 1.0 μg cm(-2) for the PGS-PCL (H) and 0.60 μg cm(-2) for the PGS-PCL (L) samples. The bioactive scaffold supports the attachment and growth of seeded myogenic and vasculogenic cell lines. In fact, rat aortic endothelial cells also display angiogenic features indicating potential for the formation of vascular tree in the scaffold. These results therefore demonstrate the prospects of VEGF-functionalized PGS-PCL fibrous scaffold as promising matrix for cardiac patch application. PMID:26270628

  1. Fabrication of electrospun SiC fibers web/phenol resin composites for the application to high thermal conducting substrate.

    PubMed

    Kim, Tae-Eon; Bae, Jin Chul; Cho, Kwang Yeon; Shul, Yong-Gun; Kim, Chang Yeoul

    2013-05-01

    Polycabosilane (PCS) could be spun to form fiber web by electrospinning PCS solution in 30% dimethylformide (DMF)/toluene solvent at 25 kV. The electrospun web is stabilized at 200 degrees C for 1 hour to connect fibers by softening PCS webs and pyrolysed to synthesize silicon carbide (SiC) webs at 1800 degrees C. The pyrolysis at 1800 degrees C increased the SiC crystal size to 45 nm from 3 nm at 1300 degrees C. However, the pyrolysis at 1800 degrees C forms pores on the surface of SiC fibers due to oxygen evaporation generated during thermals curing. SiC/phenol composite webs could be fabricated by infiltration of phenol resin and hot pressing. The thermal conductivity measurement indicates that higher SiC fibers filler contents increase the thermal conductivity up to 1.9 W/mK for 40% fraction of filler contents from 0.5 W/mK for 20% fraction of filler.

  2. Catalytic Improvement on Counter Electrode of Dye-Sensitized Solar Cells Using Electrospun Pt Nano-Fibers.

    PubMed

    Seol, Hyunwoong; Shiratani, Masaharu; Seneekatima, Kannanut; Pornprasertsuk, Rojana

    2016-04-01

    A dye-sensitized solar cell is one of cost-competitive photovoltaic devices. For higher performance, all components have been actively studied and improved. However, Pt is still a dominant catalyst since first development although some catalytic materials were studied so far. Catalytic materials of counter electrode play an important role in the performance because it supplies electrons from counter electrode to electrolyte. Therefore, the catalytic activation of counter electrode is closely connected with the performance enhancement. In this work, Pt nano-fiber was fabricated by electrospinning and applied for the counter electrode. Its wide surface area is advantageous for good conductivity and catalytic activation. Morphological characteristics of nano-fibers were analyzed according to electrospinning conditions. Photovoltaic properties, cyclic voltammetry, impedance analysis verified the catalytic activation. Consequently, dye-sensitized solar cell with Pt nano-fiber electrospun at 5.0 kV of applied voltage had higher performance than conventional dye-sensitized solar cell with Pt thin film. This work is significant for related researches because all nano-fibers counter electrode material proposed so far never exceeded the performance of conventional Pt counter electrode. PMID:27451627

  3. Synthesis and characterization of magnetic diphase ZnFe2O4 /γ-Fe2O3 electrospun fibers

    PubMed Central

    Arias, M.; Pantojas, V.M.; Perales, O.; Otaño, W.

    2011-01-01

    Magnetic nanofibers of ZnFe2O4 / γ-Fe2O3 composite were synthesized by electrospinning from a sol-gel solution containing a molar ratio Fe/Zn of 3. The effects of the calcination temperature on the phase composition, particle size and magnetic properties have been investigated. Zinc ferrite fibers were obtained by calcinating the electrospun fibers in air from 300 °C to 800 °C and characterized by thermogravimetric analyses, Fourier transformed infrared spectroscopy, x-ray photoemission spectroscopy, x-ray diffraction, vibration sample magnetometry and magnetic force microscopy. The resulting fibers, with diameters ranging from 90 to 150 nm, were ferrimagnetic with high saturation magnetization as compared to bulk. Increasing the calcination temperature resulted in an increase in particle size and saturation magnetization. The observed increase in saturation magnetization was most likely due to the formation and growth of ZnFe2O4 /γ-Fe2O3 diphase crystals. The highest saturation magnetization (45 emu/g) was obtained for fibers calcined at 800 °C. PMID:21779141

  4. Method to form a fiber/growth factor dual-gradient along electrospun silk for nerve regeneration.

    PubMed

    Dinis, Tony M; Elia, Roberto; Vidal, Guillaume; Auffret, Adrien; Kaplan, David L; Egles, Christophe

    2014-10-01

    Concentration gradients of guidance molecules influence cell behavior and growth in biological tissues and are therefore of interest for the design of biomedical scaffolds for regenerative medicine. We developed an electrospining method to generate a dual-gradient of bioactive molecules and fiber density along electrospun nanofibers without any post spinning treatment. Functionalization with fluorescent molecules demonstrated the efficiency of the method to generate a discontinuous concentration gradient along the aligned fibers. As a proof of concept for tissue engineering, the silk nanofibers were functionalized with increasing concentrations of nerve growth factor (NGF) and the biological activity was assessed and quantified with rat dorsal root ganglion (DRG) neurons cultures. Protein assays showed the absence of passive release of NGF from the functionalized fibers. The results demonstrated that the NGF concentration gradient led to an oriented and increased growth of DRG neurons (417.6 ± 55.7 μm) compared to a single uniform NGF concentration (264.5 ± 37.6 μm). The easy-to-use electrospinning technique combined with the multiple molecules that can be used for fiber functionalization makes this technique versatile for a broad range of applications from biosensors to regenerative medicine. PMID:25203247

  5. Cheap glass fiber mats as a matrix of gel polymer electrolytes for lithium ion batteries

    PubMed Central

    Zhu, Yusong; Wang, Faxing; Liu, Lili; Xiao, Shiyin; Yang, Yaqiong; Wu, Yuping

    2013-01-01

    Lithium ion batteries (LIBs) are going to play more important roles in electric vehicles and smart grids. The safety of the current LIBs of large capacity has been remaining a challenge due to the existence of large amounts of organic liquid electrolytes. Gel polymer electrolytes (GPEs) have been tried to replace the organic electrolyte to improve their safety. However, the application of GPEs is handicapped by their poor mechanical strength and high cost. Here, we report an economic gel-type composite membrane with high safety and good mechanical strength based on glass fiber mats, which are separator for lead-acid batteries. The gelled membrane exhibits high ionic conductivity (1.13 mS cm−1), high Li+ ion transference number (0.56) and wide electrochemical window. Its electrochemical performance is evaluated by LiFePO4 cathode with good cycling. The results show this gel-type composite membrane has great attraction to the large-capacity LIBs requiring high safety with low cost. PMID:24216756

  6. Glycolysis of carbon fiber-epoxy unidirectional mat catalysed by sodium hydroxide

    NASA Astrophysics Data System (ADS)

    Zaini, Mariana Binti Mohd; Badri, Khairiah Haji

    2014-09-01

    This study was conducted to recycle carbon fibre-epoxy (CFRP) composite in woven sheet/ mat form. The CFRP was recycled through glycolysis with polyethlyene glycol (PEG 200) as the solvent. The CFRP was loaded into the solvent at a ratio of 4:1 (w/w). PEG200 was diluted with water to a ratio of 80:20 (v/v). This reaction was catalysed by sodium hydroxide (NaOH) solution with varying concentrations at 1.5, 1.7 and 1.9% (w/v). The glycolysis was conducted at 180-190 °C. The recovered CF (rCF) was analysed using Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray (EDX) while the degraded solution was analysed using FTIR and the epoxy content was determined. The FTIR spectrum of the rCF exhibited the disappearance of the COC peak belonged to epoxy and supported by the SEM micrographs that showed clear rCF. On the other hand, the analysed filtrate detected the disappearance of oxygen peak element in the EDX spectrum for all rCF samples. This gave an indication that the epoxy resin has been removed from the surface of the carbon fiber.

  7. Glycolysis of carbon fiber-epoxy unidirectional mat catalysed by sodium hydroxide

    SciTech Connect

    Zaini, Mariana Binti Mohd; Badri, Khairiah Haji

    2014-09-03

    This study was conducted to recycle carbon fibre-epoxy (CFRP) composite in woven sheet/ mat form. The CFRP was recycled through glycolysis with polyethlyene glycol (PEG 200) as the solvent. The CFRP was loaded into the solvent at a ratio of 4:1 (w/w). PEG200 was diluted with water to a ratio of 80:20 (v/v). This reaction was catalysed by sodium hydroxide (NaOH) solution with varying concentrations at 1.5, 1.7 and 1.9% (w/v). The glycolysis was conducted at 180-190 °C. The recovered CF (rCF) was analysed using Fourier Transform Infrared (FTIR), Scanning Electron Microscopy (SEM) and Energy Dispersive X-Ray (EDX) while the degraded solution was analysed using FTIR and the epoxy content was determined. The FTIR spectrum of the rCF exhibited the disappearance of the COC peak belonged to epoxy and supported by the SEM micrographs that showed clear rCF. On the other hand, the analysed filtrate detected the disappearance of oxygen peak element in the EDX spectrum for all rCF samples. This gave an indication that the epoxy resin has been removed from the surface of the carbon fiber.

  8. Composite vascular scaffold combining electrospun fibers and physically-crosslinked hydrogel with copper wire-induced grooves structure.

    PubMed

    Liu, Yuanyuan; Jiang, Chen; Li, Shuai; Hu, Qingxi

    2016-08-01

    While the field of tissue engineered vascular grafts has greatly advanced, many inadequacies still exist. Successfully developed scaffolds require mechanical and structural properties that match native vessels and optimal microenvironments that foster cell integration, adhesion and growth. We have developed a small diameter, three-layered composite vascular scaffold which consists of electrospun fibers and physically-crosslinked hydrogel with copper wire-induced grooves by combining the electrospinning and dip-coating methods. Scaffold morphology and mechanics were assessed, quantified and compared to native vessels. Scaffolds were seeded with Human Umbilical Vein Endothelial Cells (HUVECs), cultured in vitro for 3 days and were evaluated for cell viability and morphology. The results showed that composite scaffolds had adjustable mechanical strength and favorable biocompatibility, which is important in the future clinical application of Tissue-engineered vascular grafts (TEVGs). PMID:26820993

  9. Chain Confinement in Electrospun Nanocomposites: using Thermal Analysis to Investigate Polymer-Filler Interactions

    SciTech Connect

    Q Ma; B Mao; P Cebe

    2011-12-31

    We investigate the interaction of the polymer matrix and filler in electrospun nanofibers using advanced thermal analysis methods. In particular, we study the ability of silicon dioxide nanoparticles to affect the phase structure of poly(ethylene terephthalate), PET. SiO{sub 2} nanoparticles (either unmodified or modified with silane) ranging from 0 to 2.0 wt% in PET were electrospun from hexafluoro-2-propanol solutions. The morphologies of both the electrospun (ES) nanofibers and the SiO{sub 2} powders were observed by scanning and transmission electron microscopy, while the amorphous or crystalline nature of the fibers was determined by real-time wide-angle X-ray scattering. The fractions of the crystal, mobile amorphous, and rigid amorphous phases of the non-woven, nanofibrous composite mats were quantified by using heat capacity measurements. The amount of the immobilized polymer layer, the rigid amorphous fraction, was obtained from the specific reversing heat capacity for both as-spun amorphous fibers and isothermally crystallized fibers. Existence of the rigid amorphous phase in the absence of crystallinity was verified in nanocomposite fibers, and two origins for confinement of the rigid amorphous fraction are proposed. Thermal analysis of electrospun fibers, including quasi-isothermal methods, provides new insights to quantitatively characterize the polymer matrix phase structure and thermal transitions, such as devitrification of the rigid amorphous fraction.

  10. Influence of low contents of superhydrophilic MWCNT on the properties and cell viability of electrospun poly (butylene adipate-co-terephthalate) fibers.

    PubMed

    Rodrigues, Bruno V M; Silva, Aline S; Melo, Gabriela F S; Vasconscellos, Luana M R; Marciano, Fernanda R; Lobo, Anderson O

    2016-02-01

    The use of poly (butylene adipate-co-terephthalate) (PBAT) in tissue engineering, more specifically in bone regeneration, has been underexplored to date due to its poor mechanical resistance. In order to overcome this drawback, this investigation presents an approach into the preparation of electrospun nanocomposite fibers from PBAT and low contents of superhydrophilic multi-walled carbon nanotubes (sMWCNT) (0.1-0.5wt.%) as reinforcing agent. We employed a wide range of characterization techniques to evaluate the properties of the resulting electrospun nanocomposites, including Field Emission Scanning Electronic Microscopy (FE-SEM), Transmission Electronic Microscopy (TEM), tensile tests, contact angle measurements (CA) and biological assays. FE-SEM micrographs showed that while the addition of sMWCNT increased the presence of beads on the electrospun fibers' surfaces, the increase of the neat charge density due to their presence reduced the fibers' average diameter. The tensile test results pointed that sMWCNT acted as reinforcement in the PBAT electrospun matrix, enhancing its tensile strength (from 1.3 to 3.6MPa with addition of 0.5wt.% of sMWCNT) and leading to stiffer materials (lower elongation at break). An evaluation using MG63 cells revealed cell attachment into the biomaterials and that all samples were viable for biomedical applications, once no cytotoxic effect was observed. MG-63 cells osteogenic differentiation, measured by ALP activity, showed that mineralized nodules formation was increased in PBAT/0.5%CNTs when compared to control group (cells). This investigation demonstrated a feasible novel approach for producing electrospun nanocomposites from PBAT and sMWCNT with enhanced mechanical properties and adequate cell viability levels, which allows for a wide range of biomedical applications for these materials. PMID:26652433

  11. Influence of low contents of superhydrophilic MWCNT on the properties and cell viability of electrospun poly (butylene adipate-co-terephthalate) fibers.

    PubMed

    Rodrigues, Bruno V M; Silva, Aline S; Melo, Gabriela F S; Vasconscellos, Luana M R; Marciano, Fernanda R; Lobo, Anderson O

    2016-02-01

    The use of poly (butylene adipate-co-terephthalate) (PBAT) in tissue engineering, more specifically in bone regeneration, has been underexplored to date due to its poor mechanical resistance. In order to overcome this drawback, this investigation presents an approach into the preparation of electrospun nanocomposite fibers from PBAT and low contents of superhydrophilic multi-walled carbon nanotubes (sMWCNT) (0.1-0.5wt.%) as reinforcing agent. We employed a wide range of characterization techniques to evaluate the properties of the resulting electrospun nanocomposites, including Field Emission Scanning Electronic Microscopy (FE-SEM), Transmission Electronic Microscopy (TEM), tensile tests, contact angle measurements (CA) and biological assays. FE-SEM micrographs showed that while the addition of sMWCNT increased the presence of beads on the electrospun fibers' surfaces, the increase of the neat charge density due to their presence reduced the fibers' average diameter. The tensile test results pointed that sMWCNT acted as reinforcement in the PBAT electrospun matrix, enhancing its tensile strength (from 1.3 to 3.6MPa with addition of 0.5wt.% of sMWCNT) and leading to stiffer materials (lower elongation at break). An evaluation using MG63 cells revealed cell attachment into the biomaterials and that all samples were viable for biomedical applications, once no cytotoxic effect was observed. MG-63 cells osteogenic differentiation, measured by ALP activity, showed that mineralized nodules formation was increased in PBAT/0.5%CNTs when compared to control group (cells). This investigation demonstrated a feasible novel approach for producing electrospun nanocomposites from PBAT and sMWCNT with enhanced mechanical properties and adequate cell viability levels, which allows for a wide range of biomedical applications for these materials.

  12. Exovascular application of epigallocatechin-3-O-gallate-releasing electrospun poly(L-lactide glycolic acid) fiber sheets to reduce intimal hyperplasia in injured abdominal aorta.

    PubMed

    Lee, Mi Hee; Kwon, Byeong-ju; Koo, Min-Ah; Jang, Eui Hwa; Seon, Gyeung Mi; Park, Jong-Chul

    2015-09-01

    Intimal hyperplasia is an excessive ingrowth of tissue resulting in chronic structural lesions commonly found at sites of atherosclerotic lesions, arterial angioplasty, vascular graft anastomoses, and other vascular abnormalities. Epigallocatechin-3-O-gallate (EGCG) was shown to elicit antioxidant, anti-proliferative, and anti-thrombogenic effects. In this study, we used an electrospinning technique to synthesize EGCG-eluting biodegradable poly(L-lactide glycolic acid) (PLGA) fiber sheets for local delivery of EGCG and investigated the effect of their exovascular application on intimal hyperplasia following balloon-induced abdominal aorta injury in a rabbit experimental model. The morphology of the composite sheets was characterized using scanning electron microscopy and Fourier transform-infrared spectroscopy. EGCG was loaded and dispersed into the PLGA-based electrospun fibers. The EGCG-loaded PLGA sheets exhibited sustained EGCG release following the initial 24 h of burst release in phosphate-buffered saline. In vivo studies demonstrated significant inhibition of intimal hyperplasia following the application of the EGCG-eluting electrospun PLGA fiber sheets, compared with vehicle PLGA controls. In conclusion, our results show that exovascular application of EGCG-eluting PLGA electrospun fiber sheets may provide a useful system for the effective local delivery of drugs for the prevention of intimal hyperplasia. PMID:26391656

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

    PubMed

    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. PMID:26142159

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

    PubMed

    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.

  15. Synthesis and characterizations of electrospun sulfonated poly (ether ether ketone) SPEEK nanofiber membrane

    NASA Astrophysics Data System (ADS)

    Hasbullah, N.; Sekak, K. A.; Ibrahim, I.

    2016-07-01

    A novel electrospun polymer electrolyte membrane (PEM) based on Sulfonated Poly (ether ether ketone) were prepared and characterized. The poly (ether ether ketone) PEEK was sulfonated using concentrated sulfuric acid at room temperature for 60 hours reaction time. The degree sulfonation (DS) of the SPEEK are 58% was determined by H1 NMR using area under the peak of the hydrogen shielding at aromatic ring of the SPEEK. Then, the functional group of the SPEEK was determined using Fourier transfer infrared (FTIR) showed O-H vibration at 3433 cm-1 of the sulfonated group (SO2-OH). The effect of the solvent and polymer concentration toward the electrospinning process was investigated which, the DMAc has electrospun ability compared to the DMSO. While, at 20 wt.% of the polymer concentration able to form a fine and uniform nanofiber, this was confirmed by FESEM that shown electrospun fiber mat SPEEK surface at nano scale diameter.

  16. Electrospun chitosan-P(LLA-CL) nanofibers for biomimetic extracellular matrix.

    PubMed

    Chen, Feng; Li, Xiaoqiang; Mo, Xiumei; He, Chuanglong; Wang, Hongsheng; Ikada, Yoshito

    2008-01-01

    Chitosan-poly(L-lactic acid-co-epsilon-caprolactone)(50:50) (P(LLA-CL)) (CS/P(LLA-CL)) blends were electrospun into nanofibers using 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) and trifluoroacetic acid (TFA) as solvents. Chitosan, which is difficult to electrospin into nanofibers, could be easily electrospun into nanofibers with addition of a small portion of P(LLA-CL). The fiber diameter depended on both the polymer concentration and the blend ratio of chitosan to P(LLA-CL). The average fiber diameter increased with increasing polymer concentration and decreasing the blend ratio of chitosan to P(LLA-CL). X-ray diffractometry (XRD) and Fourier-transform infrared (FT-IR) spectra were measured to characterize blended nanofibers. The porosity of CS/P(LLA-CL) nanofiber mats increased with increasing the weight ratio of chitosan to P(LLA-CL), while both the tensile strength and the ultimate strain increased with increasing P(LLA-CL) ratio. Fibroblast cell growth on nanofiber mats were investigated with MTT assay and scanning electron microscope (SEM) observation. The highest cell proliferation was observed on the nanofiber mats when the weight ratio of chitosan to P(LLA-CL) was 1:2. As SEM images shown, fibroblast cells showed a polygonal shape on blend nanofiber mats and migrated into the nanofiber mats.

  17. Poly-m-aramid nanofiber mats: Production for application as structural modifiers in CFRP laminates

    NASA Astrophysics Data System (ADS)

    Mazzocchetti, Laura; D'Angelo, Emanuele; Benelli, Tiziana; Belcari, Juri; Brugo, Tommaso Maria; Zucchelli, Andrea; Giorgini, Loris

    2016-05-01

    Poly(m-phenylene isophtalamide) electrospun nanofibrous membranes were produced to be used as structural reinforcements for carbon fiber reinforced composites production. In order for the polymer to be electrospun, it needs however to be fully solubilized, so the addition of some salts is required to help disrupt the tight macromolecular packing based on intra- and inter-molecular hydrogen bonding. Such salts may also contribute to the electrospinnability of the overall solution, since the provide it with a higher conductivity, whatever the solvent might be. The salt haobwever stays in the final nanofibrous mat. The membranes containing the salt are also observed to be highly hygroscopic, with a water content up to 26%, in the presence of 20%wt LiCl in the nanofibrous mat. When those membranes were interleaved among prepregs to produce a laminates, the obtained composite displayed thermal properties comparable to those of a reference nanofiber-free composite, though the former showed also easier delamination. Hence the removal of the hygroscopic salt was performed, that lead to thinner membranes, whose water content matched that of the pristine polymer. The washing step induced a thinning of the layers and of the fibers diameters, though no fiber shrinking nor membrane macroscopic damages were observed. These preliminary encouraging results thus pave the way to a deeper study of the optimized condition for producing convenient poly(m-phenylene isophtalamide) electrospun nanofibrous membranes to be used for carbon fiber reinforced composites structural modification.

  18. The Effect of Electrospun Gelatin Fibers Alignment on Schwann Cell and Axon Behavior and Organization in the Perspective of Artificial Nerve Design.

    PubMed

    Gnavi, Sara; Fornasari, Benedetta Elena; Tonda-Turo, Chiara; Laurano, Rossella; Zanetti, Marco; Ciardelli, Gianluca; Geuna, Stefano

    2015-06-08

    Electrospun fibrous substrates mimicking extracellular matrices can be prepared by electrospinning, yielding aligned fibrous matrices as internal fillers to manufacture artificial nerves. Gelatin aligned nano-fibers were prepared by electrospinning after tuning the collector rotation speed. The effect of alignment on cell adhesion and proliferation was tested in vitro using primary cultures, the Schwann cell line, RT4-D6P2T, and the sensory neuron-like cell line, 50B11. Cell adhesion and proliferation were assessed by quantifying at several time-points. Aligned nano-fibers reduced adhesion and proliferation rate compared with random fibers. Schwann cell morphology and organization were investigated by immunostaining of the cytoskeleton. Cells were elongated with their longitudinal body parallel to the aligned fibers. B5011 neuron-like cells were aligned and had parallel axon growth when cultured on the aligned gelatin fibers. The data show that the alignment of electrospun gelatin fibers can modulate Schwann cells and axon organization in vitro, suggesting that this substrate shows promise as an internal filler for the design of artificial nerves for peripheral nerve reconstruction.

  19. The Effect of Electrospun Gelatin Fibers Alignment on Schwann Cell and Axon Behavior and Organization in the Perspective of Artificial Nerve Design

    PubMed Central

    Gnavi, Sara; Fornasari, Benedetta Elena; Tonda-Turo, Chiara; Laurano, Rossella; Zanetti, Marco; Ciardelli, Gianluca; Geuna, Stefano

    2015-01-01

    Electrospun fibrous substrates mimicking extracellular matrices can be prepared by electrospinning, yielding aligned fibrous matrices as internal fillers to manufacture artificial nerves. Gelatin aligned nano-fibers were prepared by electrospinning after tuning the collector rotation speed. The effect of alignment on cell adhesion and proliferation was tested in vitro using primary cultures, the Schwann cell line, RT4-D6P2T, and the sensory neuron-like cell line, 50B11. Cell adhesion and proliferation were assessed by quantifying at several time-points. Aligned nano-fibers reduced adhesion and proliferation rate compared with random fibers. Schwann cell morphology and organization were investigated by immunostaining of the cytoskeleton. Cells were elongated with their longitudinal body parallel to the aligned fibers. B5011 neuron-like cells were aligned and had parallel axon growth when cultured on the aligned gelatin fibers. The data show that the alignment of electrospun gelatin fibers can modulate Schwann cells and axon organization in vitro, suggesting that this substrate shows promise as an internal filler for the design of artificial nerves for peripheral nerve reconstruction. PMID:26062130

  20. A hetero-core fiber optic smart mat sensor for discrimination between a moving human and object on temporal loss peaks

    NASA Astrophysics Data System (ADS)

    Hosoki, Ai; Nishiyama, Michiko; Choi, Yongwoon; Watanabe, Kazuhiro

    2011-05-01

    In this paper, we propose discrimination method between a moving human and object by means of a hetero-core fiber smart mat sensor which induces the optical loss change in time. In addition to several advantages such as flexibility, thin size and resistance to electro-magnetic interference for a fiber optic sensor, a hetero-core fiber optic sensor is sensitive to bending action of the sensor portion and independent of temperature fluctuations. Therefore, the hetero-core fiber thin mat sensor can have a fewer sensing portions than the conventional floor pressure sensors, furthermore, can detect the wide area covering the length of strides. The experimental results for human walking tests showed that the mat sensors were reproducibly working in real-time under limiting locations the foot passed in the mat sensor. Focusing on the temporal peak numbers in the optical loss, human walking and wheeled platform moving action induced the peak numbers in the range of 1 - 3 and 5 - 7, respectively, for the 10 persons including 9 male and 1 female. As a result, we conclude that the hetero-core fiber mat sensor is capable of discriminating between the moving human and object such as a wheeled platform focusing on the peak numbers in the temporal optical loss.

  1. Electrodynamic tailoring of self-assembled three-dimensional electrospun constructs

    NASA Astrophysics Data System (ADS)

    Reis, Tiago C.; Correia, Ilídio J.; Aguiar-Ricardo, Ana

    2013-07-01

    The rational design of three-dimensional electrospun constructs (3DECs) can lead to striking topographies and tailored shapes of electrospun materials. This new generation of materials is suppressing some of the current limitations of the usual 2D non-woven electrospun fiber mats, such as small pore sizes or only flat shaped constructs. Herein, we pursued an explanation for the self-assembly of 3DECs based on electrodynamic simulations and experimental validation. We concluded that the self-assembly process is driven by the establishment of attractive electrostatic forces between the positively charged aerial fibers and the already collected ones, which tend to acquire a negatively charged network oriented towards the nozzle. The in situ polarization degree is strengthened by higher amounts of clustered fibers, and therefore the initial high density fibrous regions are the preliminary motifs for the self-assembly mechanism. As such regions increase their in situ polarization electrostatic repulsive forces will appear, favoring a competitive growth of these self-assembled fibrous clusters. Highly polarized regions will evidence higher distances between consecutive micro-assembled fibers (MAFs). Different processing parameters - deposition time, electric field intensity, concentration of polymer solution, environmental temperature and relative humidity - were evaluated in an attempt to control material's design.The rational design of three-dimensional electrospun constructs (3DECs) can lead to striking topographies and tailored shapes of electrospun materials. This new generation of materials is suppressing some of the current limitations of the usual 2D non-woven electrospun fiber mats, such as small pore sizes or only flat shaped constructs. Herein, we pursued an explanation for the self-assembly of 3DECs based on electrodynamic simulations and experimental validation. We concluded that the self-assembly process is driven by the establishment of attractive

  2. In situ cross-linked electrospun fiber scaffold of collagen for fabricating cell-dense muscle tissue.

    PubMed

    Takeda, Naoya; Tamura, Kenichi; Mineguchi, Ryo; Ishikawa, Yumiko; Haraguchi, Yuji; Shimizu, Tatsuya; Hara, Yusuke

    2016-06-01

    Engineered muscle tissues used as transplant tissues in regenerative medicine should have a three-dimensional and cell-dense structure like native tissue. For fabricating a 3D cell-dense muscle tissue from myoblasts, we proposed the electrospun type I collagen microfiber scaffold of the string-shape like a harp. The microfibers were oriented in the same direction to allow the myoblasts to align, and were strung at low density with micrometer intervals to create space for the cells to occupy. To realize this shape of the scaffold, we employed in situ cross-linking during electrospinning process for the first time to collagen fibers. The collagen microfibers in situ cross-linked with glutaraldehyde stably existed in the aqueous media and completely retained the original shape to save the spaces between the fibers for over 14 days. On the contrary, the conventional cross-linking method by exposure to a glutaraldehyde aqueous solution vapor partially dissolved and damaged the fiber to lose a low-density shape of the scaffold. Myoblasts could penetrate into the interior of the in situ cross-linked string-shaped scaffold and form the cell-dense muscle tissues. Histochemical analysis showed the total area occupied by the cells in the cross section of the tissue was approximately 73 %. Furthermore, the resulting muscle tissue fabricated from primary myoblasts showed typical sarcomeric cross-striations and the entire tissue continuously pulsated by autonomous contraction. Together with the in situ cross-linking, the string-shaped scaffold provides an efficient methodology to fabricate a cell-dense 3D muscle tissue, which could be applied in regenerative medicine in future. PMID:26472433

  3. Improved cell infiltration of highly porous nanofibrous scaffolds formed by combined fiber-fiber charge repulsions and ultra-sonication

    PubMed Central

    Jeong, Sung Isn; Burns, Nancy A.; Bonino, Christopher A.; Kwon, Il Keun; Khan, Saad A.; Alsberg, Eben

    2014-01-01

    A significant problem affecting electrospun nanofibrous tissue scaffolds is poor infiltration of cells into their three-dimensional (3D) structure. Environmental and physical manipulation, however, can enhance cellular infiltration into electrospun scaffolds. In this work, RGD-modified alginate mats with increased thickness and porosity were achieved by pairing high humidity electrospinning with post-processing ultra-sonication. RGD-modified alginate, polyethylene oxide (PEO), and an FDA-approved, nonionic surfactant blends were electrospun in 20 and 50% relative humidity conditions. Mats electrospun in high humidity conditions resulted in significantly increased mat thickness and decreased fiber diameters. The mats’ alginate content was then isolated via ionic crosslinking and PEO/surfactant extraction. Finally, the alginate-only mat was post-processed by ultra-sonication to further enhance its cross-sectional thickness. Cell morphology, proliferation, and infiltration into the scaffolds were evaluated by seeding fibroblasts onto the alginate mat. Cell spreading, growth and infiltration improved with increased humidity and ultra-sonication. This approach shows great promise for the design of cell-permeable nanofibrous scaffolds for tissue-engineering applications. PMID:25530854

  4. Simultaneous Delivery of Highly Diverse Bioactive Compounds from Blend Electrospun Fibers for Skin Wound Healing.

    PubMed

    Peh, Priscilla; Lim, Natalie Sheng Jie; Blocki, Anna; Chee, Stella Min Ling; Park, Heyjin Chris; Liao, Susan; Chan, Casey; Raghunath, Michael

    2015-07-15

    Blend emulsion electrospinning is widely perceived to destroy the bioactivity of proteins, and a blend emulsion of water-soluble and nonsoluble molecules is believed to be thermodynamically unstable to electrospin smoothly. Here we demonstrate a method to retain the bioactivity of disparate fragile biomolecules when electrospun. Using bovine serum albumin as a carrier protein; water-soluble vitamin C, fat soluble vitamin D3, steroid hormone hydrocortisone, peptide hormone insulin, thyroid hormone triiodothyronine (T3), and peptide epidermal growth factor (EGF) were simultaneously blend-spun into PLGA-collagen nanofibers. Upon release, vitamin C maintained the ability to facilitate Type I collagen secretion by fibroblasts, EGF stimulated skin fibroblast proliferation, and insulin potentiated adipogenic differentiation. Transgenic cell reporter assays confirmed the bioactivity of vitamin D3, T3, and hydrocortisone. These factors concertedly increased keratinocyte and fibroblast proliferation while maintaining keratinocyte basal state. This method presents an elegant solution to simultaneously deliver disparate bioactive biomolecules for wound healing applications. PMID:26079091

  5. Effects of drug solubility, state and loading on controlled release in bicomponent electrospun fibers.

    PubMed

    Natu, Mădălina V; de Sousa, Hermínio C; Gil, M H

    2010-09-15

    Bicomponent fibers of two semi-crystalline (co)polymers, poly(varepsilon-caprolactone), and poly(oxyethylene-b-oxypropylene-b-oxyethylene), were obtained by electrospinning. Acetazolamide and timolol maleate were loaded in the fibers in different concentrations (below and above the drug solubility limit in polymer) in order to determine the effect of drug solubility in polymer, drug state, drug loading and fiber composition on fiber morphology, drug distribution and release kinetics. The high loadings fibers (with drug in crystalline form) showed higher burst and faster release than low drug content fibers, indicating the release was more sustained when the drug was encapsulated inside the fibers, in amorphous form. Moreover, timolol maleate was released faster than acetazolamide, indicating that drug solubility in polymer influences the partition of drug between polymer and elution medium, while fiber composition also controlled drug release. At low loadings, total release was not achieved (cumulative release percentages smaller than 100%), suggesting that drug remained trapped in the fibers. The modeling of release data implied a three stage release mechanism: a dissolution stage, a desorption and subsequent diffusion through water-filled pores, followed by polymer degradation control.

  6. Preparation and characterization of photocatalytic carbon dots-sensitized electrospun titania nanostructured fibers

    SciTech Connect

    Li, Haopeng; Zhu, Yihua; Cao, Huimin; Yang, Xiaoling; Li, Chunzhong

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ► The TiO{sub 2}-CDs nanostructured fibers are fabricated by using APS combining the electrospinning TiO{sub 2} nanostructured fibers and CDs. ► The CD can work as a photosensitizer in the degradation of rhodamine B under visible light irradiation. ► The TiO{sub 2}-CDs nanostructured fibers exhibit enhanced photocatalytic efficiency and can be easily handled and recycled. -- Abstract: The carbon dots (CDs) are new functional carbon-aceous materials. Compared to conventional dye molecules and semiconductor quantum dots, CDs are superior in chemical inertness and low toxicity. The TiO{sub 2}-CDs nanostructured fibers were fabricated by combining the electrospinning technique and reflux method. Compared with the pure TiO{sub 2} nanostructured fibers and P25, the TiO{sub 2}-CDs nanostructured fibers exhibited enhanced photocatalytic efficiency of photodegradation of rhodamine B (RhB) under visible light irradiation. The enhanced photocatalytic activity of TiO{sub 2}-CDs nanostructured fibers could be attributed to the presence of CDs embedded in TiO{sub 2} nanostructured fibers. The CD can work as a photosensitizer in the degradation. Furthermore, the TiO{sub 2}-CDs nanostructured fibers could be easily handled and recycled due to their one-dimensional nanostructural property.

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

    PubMed

    Baker, Stephen R; Banerjee, Soham; Bonin, Keith; Guthold, Martin

    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 440-1040nm. 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±0.3s and 8.8±3.1s, respectively. The total tensile modulus was 62±26MPa, the elastic (non-relaxing) component of the tensile modulus was 53±36MPa. 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 12MPa, 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. PMID:26652365

  8. Self-coated interfacial layer at organic/inorganic phase for temporally controlling dual-drug delivery from electrospun fibers.

    PubMed

    Zhao, Xin; Zhao, Jingwen; Lin, Zhi Yuan William; Pan, Guoqing; Zhu, Yueqi; Cheng, Yingsheng; Cui, Wenguo

    2015-06-01

    Implantable tissue engineering scaffolds with temporally programmable multi-drug release are recognized as promising tools to improve therapeutic effects. A good example would be one that exhibits initial anti-inflammatory and long-term anti-tumor activities after tumor resection. In this study, a new strategy for self-coated interfacial layer on drug-loaded mesoporous silica nanoparticles (MSNs) based on mussel-mimetic catecholamine polymer (polydopamine, PDA) layer was developed between inorganic and organic matrix for controlling drug release. When the interface PDA coated MSNs were encapsulated in electrospun poly(L-lactide) (PLLA) fibers, the release rates of drugs located inside/outside the interfacial layer could be finely controlled, with short-term release of anti-inflammation ibuprofen (IBU) for 30 days in absence of interfacial interactions and sustained long-term release of doxorubicin (DOX) for 90 days in presence of interfacial interactions to inhibit potential tumor recurrence. The DOX@MSN-PDA/IBU/PLLA hybrid fibrous scaffolds were further found to inhibit proliferation of inflammatory macrophages and cancerous HeLa cells, while supporting the normal stromal fibroblast adhesion and proliferation at different release stages. These results have suggested that the interfacial obstruction layer at the organic/inorganic phase was able to control the release of drugs inside (slow)/outside (rapid) the interfacial layer in a programmable manner. We believe such interface polymer strategy will find applications in where temporally controlled multi-drug delivery is needed. PMID:25879640

  9. Electrospun fibers of PLA/P3HT blends for device and sensor applications

    NASA Astrophysics Data System (ADS)

    Serrano, William; Pinto, Nicholas

    2013-03-01

    The thermoplastic aliphatic polyester, poly (lactic acid) (PLA) is a biodegradable polymer that is sometimes used in implant screws for bone repair. Our focus was to fabricate fibers of this polymer and its blends with p-doped poly (3-hexylthiophene)-(P3HT) in order to extend its use to devices and/or sensors. PLA/P3HT fibers were prepared in air at room temperature using the electrospinning technique that is cheap, fast and reliable. Scanning Electron Microscope images of the fibers reveal that the presence of P3HT does not affect the fabrication of PLA fibers at low or high polymer concentrations in chloroform, retaining the same morphological structure of pure PLA fibers. The fiber diameters were in the range 1-10 microns. A slight increase in fiber formation results with the addition of P3HT, most likely due to a reduction of the solution surface tension. Results of the electrical characterization of this material will be presented. DoD and NSF

  10. In vitro immersion studies of optimized electrospun bioglass 45S5 fibers for tissue engineering application

    NASA Astrophysics Data System (ADS)

    Durgalakshmi, D.; Balakumar, S.

    2015-06-01

    Bioactive-glass scaffolds are crucial in bone tissue engineering application since, they work as temporary templates for tissue regrowth and provides structural support to the cells. However, many issues remain unfolded with regard to their design. In this study, for the first time bioactive glass 45S5 fibers were synthesized using electrospinning technique. The electrospinning process parameters were optimized to obtain reproducible fibers. The effect of solvent concentration and polymer concentration on fiber formation was clearly studied. In vitro studies in simulated body fluid (SBF) were performed to investigate the bioactivity and mineralization of the scaffold by inducing the formation of hydroxyapatite (HA) crystals.

  11. Facile patterning of electrospun polymer fibers enabled by electrostatic lensing interactions

    NASA Astrophysics Data System (ADS)

    Titov, Kirill; Tan, Jin-Chong

    2016-08-01

    Hierarchical polymer fibers with long-range ordering have been straightforwardly fabricated employing a macroscale patterned mesh comprising microscale metallic filaments as a conductive collector, in an otherwise conventional electrospinning apparatus. Using electrostatic simulations, we elucidate that the patterning electric field is extremely confined to the immediate vicinity of the mesh collector surface. This lensing phenomenon is controlling the fiber patterning effect, and its strength decays with height above the patterned surface. Our study sheds new light on the physical mechanism underpinning electrospinning and offers a new approach for engineering fiber architectures where a precise control of in-plane physical properties is sought.

  12. Diameter-Dependent Modulus and Melting Behavior in Electrospun Semicrystalline Polymer Fibers

    SciTech Connect

    Y Liu; S Chen; E Zussman; C Korach; W Zhao; M Rafailovich

    2011-12-31

    Confinement of the semicrystalline polymers, poly(ethylene-co-vinyl acetate) (PEVA) and low-density polyethylene (LDPE), produced by electrospinning has been observed to produce fibers with large protrusions, which have not been previously observed in fibers of comparable diameters produced by other methods. SAXS spectra confirmed the crystalline structure and determined that the lamellar spacing was almost unchanged from the bulk. Measurement of the mechanical properties of these fibers, by both shear modulation force microscopy (SMFM) and atomic force acoustic microscopy (AFAM), indicates that the modulii of these fibers increases with decreasing diameter, with the onset at {approx}10 {micro}m, which is an order of magnitude larger than previously reported. Melting point measurements indicate a decrease of more than 7% in T{sub m}/T{sub 0} (where T{sub m} is the melting point of semicrystalline polymer fibers and T{sub 0} is the melting point of the bulk polymer) for fibers ranging from 4 to 10 {micro}m in diameter. The functional form of the decrease followed a universal curve for PEVA, when scaled with T{sub 0}.

  13. Confinement-sensitive optical response of cholesteric liquid crystals in electrospun fibers.

    PubMed

    Enz, Eva; La Ferrara, Vera; Scalia, Giusy

    2013-08-27

    Soft self-assembling photonic materials such as cholesteric liquid crystals are attractive due to their multiple unique and useful properties, in particular, an optical band gap that can be continuously and dynamically tuned in response to weak external influences, easy device integration, compatibility with flexible architectures, and, as shown here, potential for submicrometer optical applications. We study such a system formed by a short-pitch cholesteric confined in the core of polymer fibers produced by coaxial electrospinning, showing that the selective reflection arising from the helical photonic structure of the liquid crystal is present even when its confining cavity is well below a micrometer in thickness, allowing as little as just half a turn of the helix to develop. At this scale, small height variations result in a dramatic change in the reflected color, in striking difference to the bulk behavior. These conclusions are made possible by combining focused ion beam (FIB) dissection and imaging of the internal fiber morphology with optical microscopy. The FIB dissection further reveals that the cross section of the cavity within the fiber can have a shape that is quite different from that of the outside fiber. This is critical for the photonic behavior of the composite fiber because different optical textures are generated not only by change in thickness but also by the shape of the cavity. Our results provide insights into the behavior of cholesterics in submicrometer cavities and demonstrate their potential at such dimensions.

  14. Functional electrospun membranes

    NASA Astrophysics Data System (ADS)

    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.

  15. Fabrication of highly porous poly (ɛ-caprolactone) fibers for novel tissue scaffold via water-bath electrospinning.

    PubMed

    Pant, Hem Raj; Neupane, Madhav Prasad; Pant, Bishweshwar; Panthi, Gopal; Oh, Hyun-Ju; Lee, Min Ho; Kim, Hak Yong

    2011-12-01

    Highly porous fibers were prepared by water-bath electrospinning from pure poly(ɛ-caprolactone) (PCL), and its blends with methoxy poly(ethylene glycol) (MPEG). These fibers were further analyzed by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and gravimetric as well as contact angle measurement. SEM images showed that the fibers diameters as well as pores diameter on the fibers were affected by the weight ratio of MPEG/PCL. DSC and XRD not only revealed suppression of crystallinity of PCL but also indicated the presence of trace amount of MPEG in PCL water-bath collected fibers. The potential use of these hydrophilic porous electrospun fibrous mats as scaffolding materials was evaluated in vitro using mouse osteoblasts (MC3T3-E1) as reference cell lines. Cytotoxicity assessment of the fiber mats indicated that the porous electrospun mat containing trace amount of MPEG was nontoxic to the cell. Cell culture results showed that porous fibrous mats were good in promoting the cell attachment and proliferation. This novel electrospun matrix could be used as potential tissue scaffold material.

  16. Electrospun PS/PAN fibers with improved mechanical property for removal of oil from water.

    PubMed

    Li, Peng; Qiao, Ying; Zhao, Lili; Yao, Dahu; Sun, Haixiang; Hou, Yingfei; Li, Shuo; Li, Qi

    2015-04-15

    A mechanically robust and high-capacity oil sorbent is prepared by electrospinning a blend of polystyrene (PS) and polyacrylonitrile (PAN). The morphology, oil sorption capacity and mechanical property of the fibers formed in different compositions are investigated in detail. It is shown that the oil sorption capacity is a result of both the chemical composition and the specific surface area which related to diameter size. The addition of PAN as a component in fibrous sorbents can significantly improve the mechanical properties of PS fibers. Moreover, the oil sorption capacity increases with decreasing fiber diameter. The results also show that the maximum sorption capacities of the PS/PAN sorbent for pump oil, peanut oil, diesel, and gasoline were 194.85, 131.70, 66.75, and 43.38 g g(-1), respectively. Additionally, the sorbent exhibits quick oil sorption speed as well as high buoyancy, which make it a promising candidate for use as an oil spill cleanup sorbent.

  17. Electrospun nanofibers: Formation, characterization, and evaluation for nerve tissue engineering applications

    NASA Astrophysics Data System (ADS)

    Zander, Nicole E.

    The effects of fiber alignment and surface chemistry, including the covalent attachment and physical adsorption of the extracellular matrix (ECM) proteins laminin and collagen, on the neurite outgrowth of neuron-like PC12 cells were examined. Neuron-like PC12 cells responded to fiber orientation, and were successfully contact-guided by aligned electrospun nanofibers. In addition, fibers with attached protein, either physically adsorbed or covalently attached, improved neurite outgrowth lengths. Furthermore, aligning the fibers and attaching the ECM protein laminin, in particular, significantly improved neurite outgrowth over randomly oriented fibers with laminin. Since this research suggested that protein concentration on the fibers was the dominant driving force for improved neurite outgrowth, the effect of protein concentration, incorporated onto the surface of the nanofibers, on neurite outgrowth was examined. Two ways to control protein concentration on the fibers were explored—the variation of the fiber-protein reaction time and the variation of the protein soaking solution concentration. In addition, analytical methods to quantify the concentration of protein, as well as the protein coverage, on the surface of the fibers were developed. Although most of the fiber mats had multilayer protein coverage, and hence physically adsorbed proteins which could potentially mean a loss in bioactivity, the neuron-like PC12 cell neurites responded in a dose-dependent manner with increased neurite lengths on scaffolds with higher protein concentrations. The work was extended further by forming protein gradients on the fiber mats in hopes of locally directing neurite outgrowth and orientation. Fiber mats with both linear gradients (continuous change in protein concentration) and step gradients (six regions of uniform protein coverage, with protein concentration increasing from region to region) were fabricated and analyzed. The step gradients formed in the aligned fiber

  18. Effect of Fiber Diameter on the Spreading, Proliferation and Differentiation of Chondrocytes on Electrospun Chitosan Matrices

    PubMed Central

    Noriega, Sandra E.; Hasanova, Gulnara I.; Schneider, Min Jeong; Larsen, Gustavo F.; Subramanian, Anuradha

    2012-01-01

    Tissue-engineered neocartilage with appropriate biomechanical properties holds promise not only for graft applications but also as a model system for controlled studies of chondrogenesis. Our objective in the present research study is to better understand the impact of fiber diameter on the cellular activity of chondrocytes cultured on nanofibrous matrices. By using the electrospinning process, fibrous scaffolds with fiber diameters ranging from 300 nm to 1 μm were prepared and the physicomechanical properties of the scaffolds were characterized. Bovine articular chondrocytes were then seeded and maintained on the scaffolds for 7 and 14 days in culture. An upregulation in the gene expression of collagen II was noted with decreasing fiber diameters. For cells that were cultured on scaffolds with a mean fiber diameter of 300 nm, a 2-fold higher ratio of collagen II/collagen I was noted when compared to cells cultured on sponge-like scaffolds prepared by freeze drying and lyophilization. Integrin (α5, αv, β1) gene expression was also observed to be influenced by matrix morphology. Our combined results suggest that matrix geometry can regulate and promote the retention of the chondrocyte genotype. PMID:21540560

  19. Fiber diameter and seeding density influence chondrogenic differentiation of mesenchymal stem cells seeded on electrospun poly(ε-caprolactone) scaffolds.

    PubMed

    Bean, Allison C; Tuan, Rocky S

    2015-01-29

    Chondrogenic differentiation of mesenchymal stem cells is strongly influenced by the surrounding chemical and structural milieu. Since the majority of the native cartilage extracellular matrix is composed of nanofibrous collagen fibrils, much of recent cartilage tissue engineering research has focused on developing and utilizing scaffolds with similar nanoscale architecture. However, current literature lacks consensus regarding the ideal fiber diameter, with differences in culture conditions making it difficult to compare between studies. Here, we aimed to develop a more thorough understanding of how cell-cell and cell-biomaterial interactions drive in vitro chondrogenic differentiation of bone-marrow-derived mesenchymal stem cells (MSCs). Electrospun poly(ε-caprolactone) microfibers (4.3  ±  0.8 µm diameter, 90 μm(2) pore size) and nanofibers (440  ±  20 nm diameter, 1.2 μm(2) pore size) were seeded with MSCs at initial densities ranging from 1  ×  10(5) to 4  ×  10(6) cells cm(-3)-scaffold and cultured under transforming growth factor-β (TGF-β) induced chondrogenic conditions for 3 or 6 weeks. Chondrogenic gene expression, cellular proliferation, as well as sulfated glycosaminoglycan and collagen production were enhanced on microfiber in comparison to nanofiber scaffolds, with high initial seeding densities being required for significant chondrogenic differentiation and extracellular matrix deposition. Both cell-cell and cell-material interactions appear to play important roles in chondrogenic differentiation of MSCs in vitro and consideration of several variables simultaneously is essential for understanding cell behavior in order to develop an optimal tissue engineering strategy.

  20. A systematic study of captopril-loaded polyester fiber mats prepared by electrospinning.

    PubMed

    Zhang, Hua; Lou, Shaofeng; Williams, Gareth R; Branford-White, Christopher; Nie, Huali; Quan, Jing; Zhu, Li-Min

    2012-12-15

    In this study, drug-loaded nanofibers were prepared by electrospinning captopril (CPL) with aliphatic biodegradable polyesters. Poly(L-lactic acid) (PLLA), poly(lactic-co-glycolic acid) (PLGA), and poly(lactic-co-ε-caprolactone) (PLCL) were used as filament-forming matrix polymers, and the concentration of CPL in each fiber type was varied. Scanning electron microscopy indicated that the morphology and diameters of the fibers were influenced by the concentration of polymer in the spinning solution and the drug loading. CPL was found to be distributed in the polymer fibers in an amorphous manner using differential scanning calorimetry and X-ray diffraction. FTIR indicated that hydrogen bonding existed between the drug molecules and the carrier polymers. In vitro dissolution tests showed that drug release from the fibers was highly dependent on the release medium, temperature, and on the polymer used. A range of kinetic models were fitted to the drug-release data obtained, and indicated that release was diffusion controlled in all cases. The different polymer fibers have application in diverse areas of drug delivery, for instance as sub-lingual or sustained release systems. Furthermore, by combining different CPL-loaded fibers, it would be possible to produce a bespoke formulation with tailored drug-release properties. PMID:23043960

  1. Enzyme-free ethanol sensor based on electrospun nickel nanoparticle-loaded carbon fiber paste electrode.

    PubMed

    Liu, Yang; Zhang, Lei; Guo, Qiaohui; Hou, Haoqing; You, Tianyan

    2010-03-24

    We have developed a novel nickel nanoparticle-loaded carbon fiber paste (NiCFP) electrode for enzyme-free determination of ethanol. An electrospinning technique was used to prepare the NiCF composite with large amounts of spherical nanoparticles firmly embedded in carbon fibers (CF). In application to electroanalysis of ethanol, the NiCFP electrode exhibited high amperometric response and good operational stability. The calibration curve was linear up to 87.5 mM with a detection limit of 0.25 mM, which is superior to that obtained with other transition metal based electrodes. For detection of ethanol present in liquor samples, the values obtained with the NiCFP electrode were in agreement with the ones declared on the label. The attractive analytical performance and simple preparation method make this novel material promising for the development of effective enzyme-free sensors.

  2. Coaxially electrospun axon-mimicking fibers for diffusion magnetic resonance imaging.

    PubMed

    Zhou, Feng-Lei; Hubbard, Penny L; Eichhorn, Stephen J; Parker, Geoffrey J M

    2012-11-01

    The study of brain structure and connectivity using diffusion magnetic resonance imaging (dMRI) has recently gained substantial interest. However, the use of dMRI still faces major challenges because of the lack of standard materials for validation. The present work reports on brain tissue-mimetic materials composed of hollow microfibers for application as a standard material in dMRI. These hollow fibers were fabricated via a simple and one-step coaxial electrospining (co-ES) process. Poly(ε-caprolactone) (PCL) and polyethylene oxide (PEO) were employed as shell and core materials, respectively, to achieve the most stable co-ES process. These co-ES hollow PCL fibers have different inner diameters, which mainly depend on the flow rate of the core solution and have the potential to cover the size range of the brain tissue we aimed to mimic. Co-ES aligned hollow PCL fibers were characterized using optical and electron microscopy and tested as brain white matter mimics on a high-field magnetic resonance imaging (MRI) scanner. To the best of our knowledge, this is the first time that co-ES hollow fibers have been successfully used as a tissue mimic or phantom in diffusion MRI. The results of the present study provide evidence that this phantom can mimic the dMRI behavior of cellular barriers imposed by axonal cell membranes and myelin; the measured diffusivity is compatible with that of in vivo biological tissues. Together these results suggest the potential use of co-ES hollow microfibers as tissue-mimicking phantoms in the field of medical imaging.

  3. Electrospun fibers as potential carrier systems for enhanced drug release of perphenazine.

    PubMed

    Bruni, Giovanna; Maggi, Lauretta; Tammaro, Loredana; Lorenzo, Rosadele Di; Friuli, Valeria; D'Aniello, Sharon; Maietta, Mariarosa; Berbenni, Vittorio; Milanese, Chiara; Girella, Alessandro; Marini, Amedeo

    2016-09-10

    Solubility represents an important challenge for formulation of drugs, because the therapeutic efficacy of a drug depends on the bioavailability and ultimately on its solubility. Low aqueous solubility is one of the main issues related with formulation design and development of new molecules. Many drug molecules present bioavailability problems due to their poor solubility. For this reason there is a great interest in the development of new carrier systems able to enhance the dissolution of poorly water-soluble drugs. In this work, fibers containing an insoluble model drug and prepared by an electrospinning method, are proposed and evaluated to solve this problem. Two hydrophilic polymers, polyvinylpyrrolidone (Plasdone® K29/32) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus®) were used to increase the water solubility of perphenazine. The physico-chemical characterization suggests that the drug loaded in the fibers is in the amorphous state. Both polymeric carriers are effective to promote the drug dissolution rate in water, where this active pharmaceutical ingredient is insoluble, due to the fine dispersion of the drug into the polymeric matrices, obtained with this production technique. In fact, the dissolution profiles of the fibers, compared to the simple physical mixture of the two components, and to the reference commercial product Trilafon® 8mg tablets, show that a strong enhancement of the drug dissolution rate can be achieved with the electrospinning technique. PMID:27418562

  4. Electrospun fibers as potential carrier systems for enhanced drug release of perphenazine.

    PubMed

    Bruni, Giovanna; Maggi, Lauretta; Tammaro, Loredana; Lorenzo, Rosadele Di; Friuli, Valeria; D'Aniello, Sharon; Maietta, Mariarosa; Berbenni, Vittorio; Milanese, Chiara; Girella, Alessandro; Marini, Amedeo

    2016-09-10

    Solubility represents an important challenge for formulation of drugs, because the therapeutic efficacy of a drug depends on the bioavailability and ultimately on its solubility. Low aqueous solubility is one of the main issues related with formulation design and development of new molecules. Many drug molecules present bioavailability problems due to their poor solubility. For this reason there is a great interest in the development of new carrier systems able to enhance the dissolution of poorly water-soluble drugs. In this work, fibers containing an insoluble model drug and prepared by an electrospinning method, are proposed and evaluated to solve this problem. Two hydrophilic polymers, polyvinylpyrrolidone (Plasdone® K29/32) and polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (Soluplus®) were used to increase the water solubility of perphenazine. The physico-chemical characterization suggests that the drug loaded in the fibers is in the amorphous state. Both polymeric carriers are effective to promote the drug dissolution rate in water, where this active pharmaceutical ingredient is insoluble, due to the fine dispersion of the drug into the polymeric matrices, obtained with this production technique. In fact, the dissolution profiles of the fibers, compared to the simple physical mixture of the two components, and to the reference commercial product Trilafon® 8mg tablets, show that a strong enhancement of the drug dissolution rate can be achieved with the electrospinning technique.

  5. Roles of inorganic oxide nanoparticles on extraction efficiency of electrospun polyethylene terephthalate nanocomposite as an unbreakable fiber coating.

    PubMed

    Bagheri, Habib; Roostaie, Ali

    2015-01-01

    In the present work, the roles of inorganic oxide nanoparticles on the extraction efficiency of polyethylene terephthalate-based nanocomposites were extensively studied. Four fiber coatings based on polyethylene terephthalate nanocomposites containing different types of nanoparticles along with a pristine polyethylene terephthalate polymer were conveniently electrospun on stainless steel wires. The applicability of new fiber coatings were examined by headspace-solid phase microextraction of some environmentally important volatile organic compound such as benzene, toluene, ethylbenzene and xylene (BTEX), as model compounds, from aqueous samples. Subsequently, the extracted analytes were transferred into a gas chromatography by thermal desorption. Parameters affecting the morphology and capability of the prepared nanocomposites including the type of nanoparticles and their doping levels along with the coating time were optimized. Four types of nanoparticles including Fe3O4, SiO2, CoO and NiO were examined as the doping agents and among them the presence of SiO2 in the prepared nanocomposite was prominent. The homogeneity and the porous surface structure of the SiO2-polyethylene terephthalate nanocomposite were confirmed by scanning electron microscopy indicating that the nanofibers diameters were lower than 300 nm. In addition, important parameters influencing the extraction and desorption process such as temperature and extraction time, ionic strength and desorption conditions were optimized. Eventually, the developed method was validated by gas chromatography-mass spectrometry. Under optimized conditions, the relative standard deviation values for a double distilled water spiked with the selected volatile organic compounds at 50 ng L(-1) were 2-7% (n=3) while the limits of detection were between 0.7 and 0.9 ng L(-1). The method was linear in the concentration range of 10 to 1,000 ng L(-1) (R(2)>0.9992). Finally, the developed method was applied to the analysis of

  6. Fabricating and Characterizing Physical Properties of Electrospun Polypeptide-based Nanofibers

    NASA Astrophysics Data System (ADS)

    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.)

  7. Characterization of polyacrylonitrile based carbon nanofiber mats via electron beam processing.

    PubMed

    Kim, Du-Yeong; Shin, Hye-Kyoung; Jeun, Joon-Pyo; Kim, Hyun-Bin; Oh, Seung-Hwan; Kang, Phil-Hyun

    2012-07-01

    The aim of this study was to evaluate the ability of electron beam irradiation to drive stabilization reactions within PAN nanofiber mats to obtain carbon nanofiber mats. PAN nanofiber mats with fiber diameters of 300-400 nm were prepared via an electrospinning method. Electrospun PAN nanofiber mats were stabilized by electron beam irradiation with various doses up to 5,000 kGy. Using the irradiation-stabilized PAN nanofiber mats, carbon nanofibers were obtained by pyrolysis in a tube furnace for 1 h at 1,000 degrees C under an N2 atmosphere. FT-IR analysis indicated that the transformation of C[triple bond]N groups to C==N groups was accelerated by electron beam stabilization. The thermal behavior of the PAN nanofiber mats was studied using DSC and TGA. DSC thermograms showed that the peak temperatures of the exothermic reactions were found to decrease with increasing electron beam irradiation doses. Irradiation-stabilized PAN nanofiber mats were not observed to dramatically decrease in weight between 290 degrees C and 320 degrees C, an observation presumed to be related to cyclization. The char yields of PAN were found to increase with increasing irradiation doses. PMID:22966719

  8. Fiber diameter and texture of electrospun PEOT/PBT scaffolds influence human mesenchymal stem cell proliferation and morphology, and the release of incorporated compounds.

    PubMed

    Moroni, Lorenzo; Licht, Ruud; de Boer, Jan; de Wijn, Joost R; van Blitterswijk, Clemens A

    2006-10-01

    Electrospinning (ESP) has lately shown a great potential as a novel scaffold fabrication technique for tissue engineering. Scaffolds are produced by spinning a polymeric solution in fibers through a spinneret connected to a high-voltage electric field. The fibers are then collected on a support, where the scaffold is created. Scaffolds can be of different shapes, depending on the collector geometry, and have high porosity and high surface per volume ratio, since the deposited fibers vary from the microscale to the nanoscale range. Such fibers are quite effective in terms of tissue regeneration, as cells can bridge the scaffold pores and fibers, resulting in a fast and homogeneous tissue growth. Furthermore, fibers can display a nanoporous ultrastructure due to solvent evaporation. The aim of this study was to characterize electrospun scaffolds from poly(ethylene oxide terephthalate)-poly(butylene terephthalate) (PEOT/PBT) copolymers and to unravel the mechanism of pore formation on the fibers. The effect of different fiber diameters and of their surface nanotopology on cell seeding, attachment, and proliferation was studied. Smooth fibers with diameter of 10microm were found to support an optimal cell seeding and attachment within the micrometer range analyzed. Moreover, a nanoporous surface significantly enhanced cell proliferation and cells spreading on the fibers. The fabrication of ESP scaffolds with incorporated dyes with different molecular dimensions is also reported and their release measured. These findings contribute to the field of cell-material interaction and lead to the fabrication of "smart" scaffolds which can direct cells morphology and proliferation, and eventually release biological signals to properly conduct tissue formation. PMID:16762409

  9. Preparation of silica-sustained electrospun polyvinylpyrrolidone fibers with uniform mesopores via oxidative removal of template molecules by H{sub 2}O{sub 2} treatment

    SciTech Connect

    Kang, Haigang; Zhu, Yihua; Shen, Jianhua; Yang, Xiaoling; Chen, Cheng; Cao, Huimin; Li, Chungzhong

    2010-07-15

    Silica-sustained electrospun PVP fibers with uniform mesopores were synthesized via facile oxidative removal of template molecules by H{sub 2}O{sub 2} extraction. Tetraethyl orthosilicate, polyvinylpyrrolidone (PVP), and triblock poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) copolymer pluronic P{sub 123} compose the electrospinning sol to fabricate the silica-sustained PVP hybrid fibers. The effect of different post-treatment methods on the pore size distribution was investigated by calcination and extraction, respectively. Experimental results showed that oxidative removal of structure-directing agent P{sub 123} in the hybrid fibers by H{sub 2}O{sub 2} treatment can easily form narrow pore size distribution, and the incorporation of 3D silica skeleton built by hot steam aging facilitated preserving the original cylindrical morphology of fibers. Scanning electron microscopy (SEM), N{sub 2} adsorption-desorption isotherm, transmission electron microscopy (TEM), X-ray diffraction (XRD), FT-IR spectra and thermogravimetric analysis (TGA) were used to characterize the hybrid fibers. The hybrid fibers can be expected to have potential applications in drug release or tissue engineering because of their suitable pore size, large surface area and good biocompatibility.

  10. Gelatin-GAG electrospun nanofibrous scaffold for skin tissue engineering: fabrication and modeling of process parameters.

    PubMed

    Pezeshki-Modaress, Mohamad; Mirzadeh, Hamid; Zandi, Mojgan

    2015-03-01

    Electrospinning is a very useful technique for producing polymeric nanofibers by applying electrostatic forces. In this study, fabrication of novel gelatin/GAG nanofibrous mats and also the optimization of electrospinning process using response surface methodology were reported. At optimization section, gelatin/GAG blend ratio, applied voltage and feeding rate, their individual and interaction effects on the mean fiber diameter (MFD) and standard deviation of fiber diameter (SDF) were investigated. The obtained model for MFD has a quadratic relationship with gelatin/GAG blend ratio, applied voltage and feeding rate. The interactions of blend ratio and applied voltage and also applied voltage and flow rate were found significant but the interactions of blend ratio and flow rate were ignored. The optimum condition for gelatin/GAG electrospinning was also introduced using the model obtained in this study. The potential use of optimized electrospun mat in skin tissue engineering was evaluated using culturing of human dermal fibroblast cells (HDF). The SEM micrographs of HDF cells on the nanofibrous structure show that fibroblast cells can highly attach, grow and populate on the fabricated scaffold surface. The electrospun gelatin/GAG nanofibrous mats have a potential for using as scaffold for skin, cartilage and cornea tissue engineering.

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

    NASA Astrophysics Data System (ADS)

    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.

  12. Electrospun Nanostructured Fibers of Collagen-Biomimetic Apatite on Titanium Alloy

    PubMed Central

    Iafisco, Michele; Foltran, Ismaela; Sabbatini, Simona; Tosi, Giorgio; Roveri, Norberto

    2012-01-01

    Titanium and its alloys are currently the mainly used materials to manufacture orthopaedic implants due to their excellent mechanical properties and corrosion resistance. Although these materials are bioinert, the improvement of biological properties (e.g., bone implant contact) can be obtained by the application of a material that mimics the bone extracellular matrix. To this aim, this work describes a new method to produce nanostructured collagen-apatite composites on titanium alloy substrate, by combining electrospinning and biomimetic mineralization. The characterization results showed that the obtained mineralized scaffolds have morphological, structural, and chemical compositional features similar to natural bone extracellular matrix. Finally, the topographic distribution of the chemical composition in the mineralized matrix evaluated by Fourier Transform Infrared microspectroscopy demonstrated that the apatite nanocrystals cover the collagen fibers assembled by the electrospinning. PMID:22400013

  13. Protease degradable electrospun fibrous hydrogels

    PubMed Central

    Wade, Ryan J.; Bassin, Ethan J.; Rodell, Christopher B.; Burdick, Jason A.

    2015-01-01

    Electrospun nanofibers are promising in biomedical applications to replicate features of the natural extracellular matrix (ECM). However, nearly all electrospun scaffolds are either non-degradable or degrade hydrolytically, whereas natural ECM degrades proteolytically, often through matrix metalloproteinases (MMPs). Here, we synthesize reactive macromers that contain protease-cleavable and fluorescent peptides and are able to form both isotropic hydrogels and electrospun fibrous hydrogels through a photoinitiated polymerization. These biomimetic scaffolds are susceptible to protease-mediated cleavage in vitro in a protease dose dependent manner and in vivo in a subcutaneous mouse model using transdermal fluorescent imaging to monitor degradation. Importantly, materials containing an alternate and non-protease-cleavable peptide sequence are stable in both in vitro and in vivo settings. To illustrate the specificity in degradation, scaffolds with mixed fiber populations support selective fiber degradation based on individual fiber degradability. Overall, this represents a novel biomimetic approach to generate protease-sensitive fibrous scaffolds for biomedical applications. PMID:25799370

  14. Light-induced electron paramagnetic resonance evidence of charge transfer in electrospun fibers containing conjugated polymer/fullerene and conjugated polymer/fullerene/carbon nanotube blends

    SciTech Connect

    Shames, Alexander I.; Bounioux, Celine; Katz, Eugene A.; Yerushalmi-Rozen, Rachel; Zussman, Eyal

    2012-03-12

    Electrospun sub-micron fibers containing conjugated polymer (poly(3-hexylthiophene), P3HT) with a fullerene derivative, phenyl-C61-butyric acid methylester (PCBM) or a mixture of PCBM and single-walled carbon nanotubes (SWCNTs) were studied by light-induced electron paramagnetic resonance spectroscopy. The results provide experimental evidence of electron transfer between PCBM and P3HT components in both fiber systems and suggest that the presence of a dispersing block-copolymer, which acts via physical adsorption onto the PCBM and SWCNT moieties, does not prevent electron transfer at the P3HT-PCBM interface. These findings suggest a research perspective towards utilization of fibers of functional nanocomposites in fiber-based organic optoelectronic and photovoltaic devices. The latter can be developed in the textile-type large area photovoltaics or individual fiber-based solar cells that will broaden energy applications from macro-power tools to micro-nanoscale power conversion devices and smart textiles.

  15. Light-induced electron paramagnetic resonance evidence of charge transfer in electrospun fibers containing conjugated polymer/fullerene and conjugated polymer/fullerene/carbon nanotube blends

    NASA Astrophysics Data System (ADS)

    Shames, Alexander I.; Bounioux, Céline; Katz, Eugene A.; Yerushalmi-Rozen, Rachel; Zussman, Eyal

    2012-03-01

    Electrospun sub-micron fibers containing conjugated polymer (poly(3-hexylthiophene), P3HT) with a fullerene derivative, phenyl-C61-butyric acid methylester (PCBM) or a mixture of PCBM and single-walled carbon nanotubes (SWCNTs) were studied by light-induced electron paramagnetic resonance spectroscopy. The results provide experimental evidence of electron transfer between PCBM and P3HT components in both fiber systems and suggest that the presence of a dispersing block-copolymer, which acts via physical adsorption onto the PCBM and SWCNT moieties, does not prevent electron transfer at the P3HT-PCBM interface. These findings suggest a research perspective towards utilization of fibers of functional nanocomposites in fiber-based organic optoelectronic and photovoltaic devices. The latter can be developed in the textile-type large area photovoltaics or individual fiber-based solar cells that will broaden energy applications from macro-power tools to micro-nanoscale power conversion devices and smart textiles.

  16. Foreign Body Reaction Associated with PET and PET/Chitosan Electrospun Nanofibrous Abdominal Meshes

    PubMed Central

    Veleirinho, Beatriz; Coelho, Daniela S.; Dias, Paulo F.; Maraschin, Marcelo; Pinto, Rúbia; Cargnin-Ferreira, Eduardo; Peixoto, Ana; Souza, José A.; Ribeiro-do-Valle, Rosa M.; Lopes-da-Silva, José A.

    2014-01-01

    Electrospun materials have been widely explored for biomedical applications because of their advantageous characteristics, i.e., tridimensional nanofibrous structure with high surface-to-volume ratio, high porosity, and pore interconnectivity. Furthermore, considering the similarities between the nanofiber networks and the extracellular matrix (ECM), as well as the accepted role of changes in ECM for hernia repair, electrospun polymer fiber assemblies have emerged as potential materials for incisional hernia repair. In this work, we describe the application of electrospun non-absorbable mats based on poly(ethylene terephthalate) (PET) in the repair of abdominal defects, comparing the performance of these meshes with that of a commercial polypropylene mesh and a multifilament PET mesh. PET and PET/chitosan electrospun meshes revealed good performance during incisional hernia surgery, post-operative period, and no evidence of intestinal adhesion was found. The electrospun meshes were flexible with high suture retention, showing tensile strengths of 3 MPa and breaking strains of 8–33%. Nevertheless, a significant foreign body reaction (FBR) was observed in animals treated with the nanofibrous materials. Animals implanted with PET and PET/chitosan electrospun meshes (fiber diameter of 0.71±0.28 µm and 3.01±0.72 µm, respectively) showed, respectively, foreign body granuloma formation, averaging 4.2-fold and 7.4-fold greater than the control commercial mesh group (Marlex). Many foreign body giant cells (FBGC) involving nanofiber pieces were also found in the PET and PET/chitosan groups (11.9 and 19.3 times more FBGC than control, respectively). In contrast, no important FBR was observed for PET microfibers (fiber diameter = 18.9±0.21 µm). Therefore, we suggest that the reduced dimension and the high surface-to-volume ratio of the electrospun fibers caused the FBR reaction, pointing out the need for further studies to elucidate the mechanisms underlying

  17. Constitutive modelling of creep in a long fiber random glass mat thermoplastic composite

    NASA Astrophysics Data System (ADS)

    Dasappa, Prasad

    The primary objective of this proposed research is to characterize and model the creep behaviour of Glass Mat Thermoplastic (GMT) composites under thermo-mechanical loads. In addition, tensile testing has been performed to study the variability in mechanical properties. The thermo-physical properties of the polypropylene matrix including crystallinity level, transitions and the variation of the stiffness with temperature have also been determined. In this work, the creep of a long fibre GMT composite has been investigated for a relatively wide range of stresses from 5 to 80 MPa and temperatures from 25 to 90°C. The higher limit for stress is approximately 90% of the nominal tensile strength of the material. A Design of Experiments (ANOVA) statistical method was applied to determine the effects of stress and temperature in the random mat material which is known for wild experimental scatter. Two sets of creep tests were conducted. First, preliminary short-term creep tests consisting of 30 minutes creep followed by recovery were carried out over a wide range of stresses and temperatures. These tests were carried out to determine the linear viscoelastic region of the material. From these tests, the material was found to be linear viscoelastic up-to 20 MPa at room temperature and considerable non-linearities were observed with both stress and temperature. Using Time-Temperature superposition (TTS) a long term master curve for creep compliance for up-to 185 years at room temperature has been obtained. Further, viscoplastic strains were developed in these tests indicating the need for a non-linear viscoelastic viscoplastic constitutive model. The second set of creep tests was performed to develop a general non-linear viscoelastic viscoplastic constitutive model. Long term creep-recovery tests consisting of 1 day creep followed by recovery has been conducted over the stress range between 20 and 70 MPa at four temperatures: 25°C, 40°C, 60°C and 80°C. Findley's model

  18. Bicomponent electrospinning to fabricate three-dimensional hydrogel-hybrid nanofibrous scaffolds with spatial fiber tortuosity.

    PubMed

    Jin, Gyuhyung; Lee, Slgirim; Kim, Seung-Hyun; Kim, Minhee; Jang, Jae-Hyung

    2014-12-01

    Electrospun fibrous mats have emerged as powerful tissue engineering scaffolds capable of providing highly effective and versatile physical guidance, mimicking the extracellular environment. However, electrospinning typically produces a sheet-like structure, which is a major limitation associated with current electrospinning technologies. To address this challenge, highly porous, volumetric hydrogel-hybrid fibrous scaffolds were fabricated by one Taylor cone-based side-by-side dual electrospinning of poly (ε-caprolactone) (PCL) and poly (vinyl pyrrolidone) (PVP), which possess distinct properties (i.e., hydrophobic and hydrogel properties, respectively). Immersion of the resulting scaffolds in water induced spatial tortuosity of the hydrogel PVP fibers while maintaining their aligned fibrous structures in parallel with the PCL fibers. The resulting conformational changes in the entire bicomponent fibers upon immersion in water led to volumetric expansion of the fibrous scaffolds. The spatial fiber tortuosity significantly increased the pore volumes of electrospun fibrous mats and dramatically promoted cellular infiltration into the scaffold interior both in vitro and in vivo. Harmonizing the flexible PCL fibers with the soft PVP-hydrogel layers produced highly ductile fibrous structures that could mechanically resist cellular contractile forces upon in vivo implantation. This facile dual electrospinning followed by the spatial fiber tortuosity for fabricating three-dimensional hydrogel-hybrid fibrous scaffolds will extend the use of electrospun fibers toward various tissue engineering applications.

  19. Electrospinning of PEGylated polyamidoamine dendrimer fibers.

    PubMed

    Aduba, Donald C; Overlin, Jefferson W; Frierson, Chad D; Bowlin, Gary L; Yang, Hu

    2015-11-01

    Polyamidoamine (PAMAM) dendrimers have emerged as an important class of nanostructured materials and have found a broad range of applications. There is also an ongoing effort to synthesize higher-complexity structures using PAMAM dendrimers as enabling building blocks. Herein, we report for the first time the fabrication of electrospun nanocomposite fibers composed of dendrimer derivatives, namely PEGylated PAMAM dendrimers, blended with a small amount of high-molecular-weight polyethylene oxide (PEO). Morphological features and mechanical properties of the resulting dendrimer fiber mats were assessed. PMID:26249580

  20. Orientation and morphology development in electrospun nanofibers

    NASA Astrophysics Data System (ADS)

    Lin, David Yuh-Shyang

    This thesis presents the morphology and orientation development of electrospun fibers from polymer solutions with volatile solvents. Polymer solution concentration had a strong effect on the morphology of both Nylon 6,6 and poly(lactic acid) (PLLA) fibers. Successful electrospinning occurred above the overlap concentration, c* (˜0.1 wt% for Nylon 6,6 and 0.13 to 0.16 wt% for PLLA). Beaded fiber to smooth fiber transitions (5.4 to 8.3 wt% for Nylon 6,6 and 3.0 wt% for PLLA) were observed around the entanglement concentrations, ce, corresponding to entanglement characteristic values, [eta]C, of 5.4 to 8.5 (Nylon 6,6) and 20 to 24 (PLLA). Processing parameters, including DC voltage (VD), AC voltage (VA), frequency of VA, and tip-to-target distance, did not significantly affect the morphology of electrospun Nylon 6,6 fibers, but increasing VA or frequency resulted in more uniform fibers. Fully-aligned, defect-free PLLA scaffolds with diameters between 200 and 800 nm were electrospun by decreasing the solution feed rate, increasing the voltage and tip-to-target distance, and using concentrations near the beaded to smooth fiber transition. Neurites from dorsal root ganglion (DRG) explants that were seeded on these scaffolds were shown to follow the direction of these fibers upon contact. After 12 days, these neurites still adhered to the fibers and extended ˜1.5 to 2 cm from their original contact position. Neuroblastoma (SH-EP and SH-SY5Y) and Schwann cells were found to elongate and align parallel to the direction of the fibers. Orientation of electrospun fibers was found to be a function of fiber diameters. Polarized light optical microscopy was used to characterize banded structures in electrospun poly(hexyl isocyanate) (PHIC) fibers. The orientational order observed in fibers with diameters between 2 mum and 13 mum increased linearly with decreasing diameters. The structure of electrospun PLLA fibers was determined to be the beta structure. Using the intensity

  1. Influence of electrospun fiber mesh size on hMSC oxygen metabolism in 3D collagen matrices: experimental and theoretical evidences.

    PubMed

    Guaccio, Angela; Guarino, Vincenzo; Perez, Marco A Alvarez-; Cirillo, Valentina; Netti, Paolo A; Ambrosio, Luigi

    2011-08-01

    The traditional paradigm of tissue engineering of regenerating in vitro tissue or organs, through the combination of an artificial matrix and a cellular population has progressively changed direction. The most recent concept is the realization of a fully functional biohybrid, where both, the artificial and the biotic phase, concur in the formation of the novel organic matter. In this direction, interest is growing in approaches taking advantage of the control at micro- and nano-scale of cell material interaction based on the realization of elementary tassels of cells and materials which constitute the beginning point for the expansion of 3D more complex structures. Since a spontaneous assembly of all these components is expected, however, it becomes more fundamental than ever to define the features influencing cellular behavior, either they were material functional properties, or material architecture. In this work, it has been investigated the direct effect of electrospun fiber sizes on oxygen metabolism of h-MSC cells, when any other culture parameter was kept constant. To this aim, thin PCL electrospun membranes, with micro- and nano-scale texturing, were layered between two collagen slices up to create a sandwich structure (µC-PCL-C and nC-PCL-C). Cells were seeded on membranes, and the oxygen consumption was determined by a phosphorescence quenching technique. Results indicate a strong effect of the architecture of scaffolds on cell metabolism, also revealed by the increasing of HIF1-α gene expression in nC-PCL-C. These findings offer new insights into the role of materials in specific cell activities, also implying the existence of very interesting criteria for the control of tissue growth through the tuning of scaffold architecture.

  2. Electrospun meshes possessing region-wise differences in fiber orientation, diameter, chemistry and mechanical properties for engineering bone-ligament-bone tissues.

    PubMed

    Samavedi, Satyavrata; Vaidya, Prasad; Gaddam, Prudhvidhar; Whittington, Abby R; Goldstein, Aaron S

    2014-12-01

    Although bone-patellar tendon-bone (B-PT-B) autografts are the gold standard for repair of anterior cruciate ligament ruptures, they suffer from drawbacks such as donor site morbidity and limited supply. Engineered tissues modeled after B-PT-B autografts are promising alternatives because they have the potential to regenerate connective tissue and facilitate osseointegration. Towards the long-term goal of regenerating ligaments and their bony insertions, the objective of this study was to construct 2D meshes and 3D cylindrical composite scaffolds - possessing simultaneous region-wise differences in fiber orientation, diameter, chemistry and mechanical properties - by electrospinning two different polymers from off-set spinnerets. Using a dual drum collector, 2D meshes consisting of an aligned polycaprolactone (PCL) fiber region, randomly oriented poly(lactide-co-glycolide) (PLGA) fiber region and a transition region (comprised of both PCL and PLGA fibers) were prepared, and region-wise differences were confirmed by microscopy and tensile testing. Bone marrow stromal cells (BMSCs) cultured on these meshes exhibited random orientations and low aspect ratios on the random PLGA regions, and high aspect ratios and alignment on the aligned PCL regions. Next, meshes containing an aligned PCL region flanked by two transition regions and two randomly oriented PLGA regions were prepared and processed into 3D cylindrical composite scaffolds using an interpenetrating photo-crosslinkable polyethylene glycol diacrylate hydrogel to recapitulate the shape of B-PT-B autografts. Tensile testing indicated that cylindrical composites were mechanically robust, and eventually failed due to stress concentration in the aligned PCL region. In summary, this study demonstrates a process to fabricate electrospun meshes possessing region-wise differences in properties that can elicit region-dependent cell responses, and be readily processed into scaffolds with the shape of B-PT-B autografts.

  3. A Cyanine Dye Encapsulated Porous Fibrous Mat for Naked-Eye Ammonia Sensing.

    PubMed

    Ji, Chendong; Ma, Lijing; Yin, Meizhen; Yang, Wantai; Pan, Kai

    2016-08-19

    Electrospun ultrathin fiber-based sensors are desirable because of their practicality and sensitivity. Ammonia-detection systems are in high demand in different areas, including the industrial and agricultural fields. However, current technologies rely on large and complex instruments that restrict their actual utilization. Herein, we report a flexible naked-eye ammonia sensor, the polylactic acid-cyanine (PLA-Cy) fibrous mat, which was fabricated by blending a carboxyl-functionalized cyanine dye (D1) into electospun PLA porous fibers. The sensing mat was shown to undergo a naked-eye-detectable color change from white to blue upon exposure to ammonia vapor. The mat showed high selectivity to ammonia gas with a detection limit of 3.3 ppm. Aggregated D1 was first encapsulated by PLA and was then ionized by NH3 . These mechanisms were examined by photophysical studies and scanning electron microscopy. The aggregation-deaggregation process of D1 in the PLA-Cy fibrous mat led to the color change. This work provides a facile method for the naked-eye detection of ammonia and a novel strategy for the use of organic dyes in ammonia sensing.

  4. A Cyanine Dye Encapsulated Porous Fibrous Mat for Naked-Eye Ammonia Sensing.

    PubMed

    Ji, Chendong; Ma, Lijing; Yin, Meizhen; Yang, Wantai; Pan, Kai

    2016-08-19

    Electrospun ultrathin fiber-based sensors are desirable because of their practicality and sensitivity. Ammonia-detection systems are in high demand in different areas, including the industrial and agricultural fields. However, current technologies rely on large and complex instruments that restrict their actual utilization. Herein, we report a flexible naked-eye ammonia sensor, the polylactic acid-cyanine (PLA-Cy) fibrous mat, which was fabricated by blending a carboxyl-functionalized cyanine dye (D1) into electospun PLA porous fibers. The sensing mat was shown to undergo a naked-eye-detectable color change from white to blue upon exposure to ammonia vapor. The mat showed high selectivity to ammonia gas with a detection limit of 3.3 ppm. Aggregated D1 was first encapsulated by PLA and was then ionized by NH3 . These mechanisms were examined by photophysical studies and scanning electron microscopy. The aggregation-deaggregation process of D1 in the PLA-Cy fibrous mat led to the color change. This work provides a facile method for the naked-eye detection of ammonia and a novel strategy for the use of organic dyes in ammonia sensing. PMID:27411059

  5. Effect of natural fiber types and sodium silicate coated on natural fiber mat/PLA composites: Tensile properties and rate of fire propagation

    NASA Astrophysics Data System (ADS)

    Thongpin, C.; Srimuk, J.; hipkam, N.; Wachirapong, P.

    2015-07-01

    In this study, 3 types of natural fibres, i.e. jute, sisal and abaca, were plain weaved to fibre mat. Before weaving, the fibres were treated with 5% NaOH to remove hemi cellulose and lignin. The weaving was performed by hand using square wooden block fit with nails for weaving using one and two types of natural fibres as weft and warp fibre to produce natural fibre mat. The fibre mat was also impregnated in sodium silicate solution extracted from rich husk ash. The pH of the solution was adjusted to pH 7 using H2SO4 before impregnation. After predetermined time, sodium silicate was gelled and deposited on the mat. The fabric mat and sodium silicate coated mat were then impregnated with PLA solution to produce prepreg. Dried pepreg was laminated with PLA sheet using compressing moulding machine to obtain natural fibre mat/PLA composite. The composite containing abaca aligned in longitudinal direction with respect to tension force enhanced Young's modulus more than 300%. Fibre mat composites with abaca aligned in longitudinal direction also showed tensile strength enhancement nearly 400% higher than neat PLA. After coating with sodium silicate, the tensile modulus of the composites was found slightly increased. The silicate coating was disadvantage on tensile strength of the composite due to the effect of sodium hydroxide solution that was used as solvent for silicate extraction from rice husk ash. However, sodium silicate could retard rate of fire propagation about 50%compare to neat PLA and about 10% reduction compared to fibre mat composites without sodium silicate coated fibre mat.

  6. Fluorine-Enriched Melt-Blown Fibers from Polymer Blends of Poly(butylene terephthalate) and a Fluorinated Multiblock Copolyester.

    PubMed

    Wang, Zaifei; Macosko, Christopher W; Bates, Frank S

    2016-01-13

    Melt-blown fibers (dav ∼1 μm) were produced from blends of poly(butylene terephthalate) (PBT) and a partially fluorinated random multiblock copolyester (PFCE) leading to enhanced hydrophobicity and even superhydrophobicity (static water contact angle = 157 ± 3°) of the associated fiber mats. XPS measurements demonstrated quantitatively that the surface fluorine content increased systematically with the bulk loading of PFCE, rising to nearly 20 atom %, which corresponds to 41 wt % PFCE at a bulk loading of 10 wt %. The PBT/PFCE fibers exhibit greater fluorine surface segregation than either melt-blown PBT/poly(ethylene-co-chlorotrifluoroethylene) (PBT/PECTFE) fibers or electrospun fibers obtained from blends of poly(styrene) and fluoroalkyl end-capped polystyrene (PS/PSCF). Dynamic contact angle measurements further demonstrated decreased surface adhesion energy of the melt-blown PBT/PFCE fiber mats due to the blooming of PFCE to the surface.

  7. Method for production of carbon nanofiber mat or carbon paper

    SciTech Connect

    Naskar, Amit K.

    2015-08-04

    Method for the preparation of a non-woven mat or paper made of carbon fibers, the method comprising carbonizing a non-woven mat or paper preform (precursor) comprised of a plurality of bonded sulfonated polyolefin fibers to produce said non-woven mat or paper made of carbon fibers. The preforms and resulting non-woven mat or paper made of carbon fiber, as well as articles and devices containing them, and methods for their use, are also described.

  8. pH responsive polyurethane (core) and cellulose acetate phthalate (shell) electrospun fibers for intravaginal drug delivery.

    PubMed

    Hua, Dawei; Liu, Zhongche; Wang, Fang; Gao, Buhong; Chen, Fei; Zhang, Qilu; Xiong, Ranhua; Han, Jingquan; Samal, Sangram Keshari; De Smedt, Stefaan C; Huang, Chaobo

    2016-10-20

    In this study we present the use of co-axial electrospinning to produce core-shell composite micro-/nano- fibers of polyurethane (PU) and cellulose acetate phthalate (CAP). The designed fibers possess enhanced mechanical properties with a tensile strength of 13.27±2.32MPa, which is a clear improvement over the existing CAP fibers that suffer from a poor mechanical strength (0.2±0.03MPa). The CAP imparts pH responsiveness to the core-shell structure giving the fibers potential for "semen sensitive" (intravaginal) drug delivery. PMID:27474676

  9. pH responsive polyurethane (core) and cellulose acetate phthalate (shell) electrospun fibers for intravaginal drug delivery.

    PubMed

    Hua, Dawei; Liu, Zhongche; Wang, Fang; Gao, Buhong; Chen, Fei; Zhang, Qilu; Xiong, Ranhua; Han, Jingquan; Samal, Sangram Keshari; De Smedt, Stefaan C; Huang, Chaobo

    2016-10-20

    In this study we present the use of co-axial electrospinning to produce core-shell composite micro-/nano- fibers of polyurethane (PU) and cellulose acetate phthalate (CAP). The designed fibers possess enhanced mechanical properties with a tensile strength of 13.27±2.32MPa, which is a clear improvement over the existing CAP fibers that suffer from a poor mechanical strength (0.2±0.03MPa). The CAP imparts pH responsiveness to the core-shell structure giving the fibers potential for "semen sensitive" (intravaginal) drug delivery.

  10. Preparation and Characterization of Coaxial Electrospun Fibers Containing Triclosan for Comparative Study of Release Properties with Amoxicillin and Epicatechin.

    PubMed

    Rodríguez-Félix, D E; Castillo-Ortega, M M; Nájera-Luna, A L; Montaño-Figueroa, A G; López-Peña, I Y; Del Castillo-Castro, T; Rodríguez-Félix, F; Quiroz-Castilloc, J M; Herrera-Franco, P J

    2016-01-01

    The optimal conditions for the fibers preparation of cellulose acetate (CA) and poly(vinyl pyrrolidone) (PVP) containing triclosan within the fiber were successfully found; the physicochemical characteristics of these fibrous membranes were corroborated by FTIR spectroscopy, thermal analysis, mechanical tests, SEM , and TEM analysis. The formation of composite fibers of CA and PVP containing triclosan at the core of the fiber was evidenced. A comparative study of the release properties of amoxicillin, epicatechin or triclosan embedded into fibers CA/PVP/CA was performed. As more interactions of the drug with CA or PVP occur, slower release of the drug into the release medium takes place. Regarding the drug delivery system design, it is important to consider the possible molecular interactions between the material components and predict how fast or slow the drug will be delivered into the corresponding medium. PMID:26634788

  11. Conductivity and touch-sensor application for atomic layer deposition ZnO and Al:ZnO on nylon nonwoven fiber mats

    SciTech Connect

    Sweet, William J.; Oldham, Christopher J.; Parsons, Gregory N.

    2015-01-15

    Flexible electronics and wearable technology represent a novel and growing market for next generation devices. In this work, the authors deposit conductive zinc oxide films by atomic layer deposition onto nylon-6 nonwoven fiber mats and spun-cast films, and quantify the impact that deposition temperature, coating thickness, and aluminum doping have on the conductivity of the coated substrates. The authors produce aluminum doped zinc oxide (AZO) coated fibers with conductivity of 230 S/cm, which is ∼6× more conductive than ZnO coated fibers. Furthermore, the authors demonstrate AZO coated fibers maintain 62% of their conductivity after being bent around a 3 mm radius cylinder. As an example application, the authors fabricate an “all-fiber” pressure sensor using AZO coated nylon-6 electrodes. The sensor signal scales exponentially under small applied force (<50 g/cm{sup 2}), yielding a ∼10{sup 6}× current change under 200 g/cm{sup 2}. This lightweight, flexible, and breathable touch/force sensor could function, for example, as an electronically active nonwoven for personal or engineered system analysis and diagnostics.

  12. Heat Transfer Enhancement in Forced Convective Boiling in Microchannels by Periodic Electrospun Nanofiber Coatings

    NASA Astrophysics Data System (ADS)

    Yarin, Alexander; Freystein, Martin; Kolberg, Felix; Sinha-Ray, Sumit; Sahu, Rakesh; Spiegel, Lucas; Gambaryan-Roisman, Tatiana; Stephan, Peter

    2015-03-01

    To enhance heat transfer in forced convective boiling the microchannel bottom was amended by a nano-texture - periodic rectangular mats of electrospun polymer nanofibers. The fibers were ~ 300-500 nm in diameter and the mat thicknesses were about 6-15 μm. The test fluid was FC-72 and the flow in microchannels contained trains of Taylor bubbles. The role of the nanofibers was to retain the warm microchannel bottom wet, to prevent dry-out and thus to enhance the heat removal rate. In the present experiments the time-average heat flux and heat transfer coefficient at the nanofiber-coated domains were found to be 1.5-2 times higher than those at the uncoated ones. Accordingly, a significant decrease (by 5-8 K) in the superheat was observed at the same Re of 387 and power supply of 36.1 kW/m2. At a higher Re of 432 and lower power supply of 28.1 kW/m2 similar trends in the heat removal rate and surface superheat were found. The significant enhancement of the heat transfer results from the fact that nanofiber mats facilitate wetting of surface under passing Taylor bubbles, thus delaying formation of vapor flow at the channel bottom. The interstices of the nanofiber mat act as the nucleation sites facilitating formation of tiny bubbles, which eventually results in a higher heat removal rate from the surface at a reduced superheat.

  13. Electrospun Nafion®/Polyphenylsulfone composite membranes for regenerative Hydrogen bromine fuel cells

    DOE PAGES

    Park, Jun; Wycisk, Ryszard; Pintauro, Peter N.; Yarlagadda, Venkata; Van Nguyen, Trung

    2016-02-29

    Here, the regenerative H2/Br2-HBr fuel cell, utilizing an oxidant solution of Br2 in aqueous HBr, shows a number of benefits for grid-scale electricity storage. The membrane-electrode assembly, a key component of a fuel cell, contains a proton-conducting membrane, typically based on the perfluorosulfonic acid (PFSA) ionomer. Unfortunately, the high cost of PFSA membranes and their relatively high bromine crossover are serious drawbacks. Nanofiber composite membranes can overcome these limitations. In this work, composite membranes were prepared from electrospun dual-fiber mats containing Nafion® PFSA ionomer for facile proton transport and an uncharged polymer, polyphenylsulfone (PPSU), for mechanical reinforcement, and swelling control.more » After electrospinning, Nafion/PPSU mats were converted into composite membranes by softening the PPSU fibers, through exposure to chloroform vapor, thus filling the voids between ionomer nanofibers. It was demonstrated that the relative membrane selectivity, referenced to Nafion® 115, increased with increasing PPSU content, e.g., a selectivity of 11 at 25 vol% of Nafion fibers. H2-Br2 fuel cell power output with a 65 m thick membrane containing 55 vol% Nafion fibers was somewhat better than that of a 150 m Nafion® 115 reference, but its cost advantage due to a four-fold decrease in PFSA content and a lower bromine species crossover make it an attractive candidate for use in H2/Br2-HBr systems.« less

  14. Hyperbranched polyglycerol electrospun nanofibers for wound dressing applications.

    PubMed

    Vargas, E A Torres; do Vale Baracho, N C; de Brito, J; de Queiroz, A A A

    2010-03-01

    This study reports on the performance of electrospun hyperbranched polyglycerol nanofibers capable of providing an active agent delivery for wound dressing applications. The aim of this work was to prepare electrospun HPGL nanofibers containing Calendula officinalis as a wound-healing and anti-inflammatory agent. The morphology of the electrospun HPGL-C. officinalis nanofibers was analyzed using a scanning electron microscope. The results showed that the diameters of the fibers were in nanoscales. The release of C. officinalis from the electrospun HPGL fibers was determined by HPLC at a physiological temperature (37 degrees C). Rapid release of the C. officinalis from the electrospun HPGL-C. officinalis nanofibers was exhibited as result of the high swelling ability as well as the high porosity of the electrospun HPGL-C. officinalis membranes. The degree of swelling, and the mechanical and biocompatible properties of the electrospun HPGL fibers were determined. The results showed that, in physiological conditions, the water absorption into the HPGL electrospun fibers slowed down, governed by the rate at which the electrospun HPGL-C. officinalis membranes interacted with the physiological fluid. The rate of release of C. officinalis seemed to depend on the C. officinalis content in the HPGL nanofibers. From the elastic modulus, it could be seen that elastic electrospun HPGL fibers were obtained with increments of C. officinalis content in the HPGL-C. officinalis membranes. The results of in vivo experiments in rats suggested that HPGL-C. officinalis might be an interesting bioactive wound dressing material for clinical applications.

  15. Bi-layer Al2O3/ZnO atomic layer deposition for controllable conductive coatings on polypropylene nonwoven fiber mats

    NASA Astrophysics Data System (ADS)

    Sweet, William J.; Jur, Jesse S.; Parsons, Gregory N.

    2013-05-01

    Electrically conductive zinc oxide coatings are applied to polypropylene nonwoven fiber mats by atomic layer deposition (ALD) at 50-155 °C. A low temperature (50 °C) aluminum oxide ALD base layer on the polypropylene limits diffusion of diethyl zinc into the polypropylene, resulting in ZnO layers with properties similar to those on planar silicon. Effective conductivity of 63 S/cm is achieved for ZnO on Al2O3 coated polypropylene fibers, and the fibers remain conductive for months after coating. Without the Al2O3 precoating, the effective conductivity was much smaller, consistent with precursor diffusion into the polymer and sub-surface ZnO nucleation. Mechanical robustness tests showed that conductive samples bent around a 6 mm radius maintained up to 40% of the pre-bending conductivity. Linkages between electrical conductivity and mechanical performance will help inform materials choice for flexible and porous electronics including textile-based sensors and antennas.

  16. Studies of magnetic alginate-based electrospun matrices crosslinked with different methods for potential hyperthermia treatment.

    PubMed

    Chen, Yen-Hsuan; Cheng, Chi-Hui; Chang, Wan-Ju; Lin, Yi-Ching; Lin, Feng-Huei; Lin, Jui-Che

    2016-05-01

    The magnetic electrospun mats were lately established as an innovative biomaterial for hyperthermic cancer treatment. Unlike those surface-modified magnetic nanoparticles that may not firmly adhere onto the tumor for long-term duration, the magnetic mats with nanofibrous structure can promote cell adhesion and kill the tumor directly within an alternating magnetic field. However, most magnetic electrospun mats were fabricated using non-biodegradable polymers and organic solvents, causing the problems of removal after therapy and the suspected biotoxicity associated with residual solvent. Alginate (SA) was utilized in this investigation as the main material for electrospinning because of being biodegradable and water-soluble. The alginate-based electrospun mats were then treated by an ionic or a covalent crosslinking method, and then followed by chelation with Fe(2+)/Fe(3+) for chemical coprecipitation of Fe3O4 magnetic nanoparticles. Significant less cytotoxicity was noted on both liquid extracts from the ionic-crosslinked (Fe3O4-SA/PEO) and covalent-crosslinked (Fe3O4-SA/PVA) magnetic electrospun mats as well as the surface of Fe3O4-SA/PVA. In vitro hyperthermia assay indicated that the covalent-crosslinked magnetic alginate-based mats reduced tumor cell viability greater than Fe3O4 nanoparticles. Such magnetic electrospun mats are of potential for hyperthermia treatment by endoscopic/surgical delivery as well as serving as a supplementary debridement treatment after surgical tumor removal. PMID:26952432

  17. Long TiO2 hollow fibers with mesoporous walls: sol-gel combined electrospun fabrication and photocatalytic properties.

    PubMed

    Zhan, Sihui; Chen, Dairong; Jiao, Xiuling; Tao, Caihong

    2006-06-15

    Long TiO2 hollow fibers with mesoporous walls have been fabricated with the sol-gel combined two-capillary spinneret electrospinning technique using a triblock copolymer (Pluronic, P123, (H(C2H5O)20(C3H7O)70 (C2H5O)20OH) as a pore-directing agent. The as-prepared hollow fibers were as long as 30 cm with an outer diameter of 0.1-4 microm and wall thickness of 60-500 nm. The diameters and wall thicknesses of the hollow fibers could be tuned by adjusting the electrospinning parameters. The fiber walls were composed of mesopores 6.7 nm in diameter as calculated from the N2 adsorption/desorption isotherm. The high-resolution TEM (HR-TEM) images exhibited that the mesopores were hexagonally aligned with a low order because of the curving of the pores. When comparing with other nanostructured TiO2 materials such as commercial TiO2 nanoparticles (P25, Degussa) and mesoporous TiO2 powders, the hollow fibers exhibited higher photocatalytic activities toward degradation of methylene blue and gaseous formaldehyde.

  18. Synthesis of piroxicam loaded novel electrospun biodegradable nanocomposite scaffolds for periodontal regeneration.

    PubMed

    Farooq, Ariba; Yar, Muhammad; Khan, Abdul Samad; Shahzadi, Lubna; Siddiqi, Saadat Anwar; Mahmood, Nasir; Rauf, Abdul; Qureshi, Zafar-ul-Ahsan; Manzoor, Faisal; Chaudhry, Aqif Anwar; ur Rehman, Ihtesham

    2015-11-01

    Development of biodegradable composites having the ability to suppress or eliminate the pathogenic micro-biota or modulate the inflammatory response has attracted great interest in order to limit/repair periodontal tissue destruction. The present report includes the development of non-steroidal anti-inflammatory drug encapsulated novel biodegradable chitosan (CS)/poly(vinyl alcohol) (PVA)/hydroxyapatite (HA) electro-spun (e-spun) composite nanofibrous mats and films and study of the effect of heat treatment on fibers and films morphology. It also describes comparative in-vitro drug release profiles from heat treated and control (non-heat treated) nanofibrous mats and films containing varying concentrations of piroxicam (PX). Electrospinning was used to obtain drug loaded ultrafine fibrous mats. The physical/chemical interactions were evaluated by Fourier Transform Infrared (FT-IR) spectroscopy. The morphology, structure and pore size of the materials were investigated by scanning electron microscopy (SEM). The thermal behavior of the materials was investigated by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Control (not heat treated) and heat treated e-spun fibers mats and films were tested for in vitro drug release studies at physiological pH7.4 and initially, as per requirement burst release patterns were observed from both fibers and films and later sustained release profiles were noted. In vitro cytocompatibility was performed using VERO cell line of epithelial cells and all the synthesized materials were found to be non-cytotoxic. The current observations suggested that these materials are potential candidates for periodontal regeneration. PMID:26249571

  19. Synthesis of piroxicam loaded novel electrospun biodegradable nanocomposite scaffolds for periodontal regeneration.

    PubMed

    Farooq, Ariba; Yar, Muhammad; Khan, Abdul Samad; Shahzadi, Lubna; Siddiqi, Saadat Anwar; Mahmood, Nasir; Rauf, Abdul; Qureshi, Zafar-ul-Ahsan; Manzoor, Faisal; Chaudhry, Aqif Anwar; ur Rehman, Ihtesham

    2015-11-01

    Development of biodegradable composites having the ability to suppress or eliminate the pathogenic micro-biota or modulate the inflammatory response has attracted great interest in order to limit/repair periodontal tissue destruction. The present report includes the development of non-steroidal anti-inflammatory drug encapsulated novel biodegradable chitosan (CS)/poly(vinyl alcohol) (PVA)/hydroxyapatite (HA) electro-spun (e-spun) composite nanofibrous mats and films and study of the effect of heat treatment on fibers and films morphology. It also describes comparative in-vitro drug release profiles from heat treated and control (non-heat treated) nanofibrous mats and films containing varying concentrations of piroxicam (PX). Electrospinning was used to obtain drug loaded ultrafine fibrous mats. The physical/chemical interactions were evaluated by Fourier Transform Infrared (FT-IR) spectroscopy. The morphology, structure and pore size of the materials were investigated by scanning electron microscopy (SEM). The thermal behavior of the materials was investigated by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC). Control (not heat treated) and heat treated e-spun fibers mats and films were tested for in vitro drug release studies at physiological pH7.4 and initially, as per requirement burst release patterns were observed from both fibers and films and later sustained release profiles were noted. In vitro cytocompatibility was performed using VERO cell line of epithelial cells and all the synthesized materials were found to be non-cytotoxic. The current observations suggested that these materials are potential candidates for periodontal regeneration.

  20. Electrospun FeS2@Carbon Fiber Electrode as a High Energy Density Cathode for Rechargeable Lithium Batteries.

    PubMed

    Zhu, Yujie; Fan, Xiulin; Suo, Liumin; Luo, Chao; Gao, Tao; Wang, Chunsheng

    2016-01-26

    In this study, an FeS2@carbon fiber electrode is developed with FeS2 nanoparticles either embedded in or attached to carbon fibers by using an electrospinning method. By applying this binder-free, metal-current-collector-free FeS2@carbon fiber electrode, both the redox reaction and capacity decay mechanisms for the Li-FeS2 system are revealed by changing the electrolyte (conventional carbonate electrolyte and a "solvent-in-salt"-type Li-S battery electrolyte) and working voltage ranges (1.0-3.0 V and 1.5-3.0 V vs Li/Li(+)). The FeS2@carbon fiber electrode shows stable cycling performance in both the conventional carbonate electrolyte and the solvent-in-salt-type Li-S battery electrolyte in the voltage range of 1.5-3.0 V. Electrochemical tests in the solvent-in-salt-type Li-S battery electrolyte indicate that the Li-FeS2 system becomes a hybrid of the Li-S cell and Li-iron sulfide cell after the initial cycle. Based on the understanding on the capacity decay mechanisms, the cycling stability of the Li-FeS2 system in the voltage range of 1.0-3.0 V is then significantly enhanced by coating the FeS2@carbon fiber electrode with a thin layer of Al2O3. The Al2O3-coated electrode demonstrates excellent cycling performance with high discharge energy densities at both the material level (∼1300 Wh/kg-FeS2) and the electrode level (∼1000 Wh/kg-FeS2 electrode). PMID:26700975

  1. Therapeutic-designed electrospun bone scaffolds: mesoporous bioactive nanocarriers in hollow fiber composites to sequentially deliver dual growth factors.

    PubMed

    Kang, Min Sil; Kim, Joong-Hyun; Singh, Rajendra K; Jang, Jun-Hyeog; Kim, Hae-Won

    2015-04-01

    A novel therapeutic design of nanofibrous scaffolds, holding a capacity to load and deliver dual growth factors, that targets bone regeneration is proposed. Mesoporous bioactive glass nanospheres (MBNs) were used as bioactive nanocarriers for long-term delivery of the osteogenic enhancer fibroblast growth factor 18 (FGF18). Furthermore, a core-shell structure of a biopolymer fiber made of polyethylene oxide/polycaprolactone was introduced to load FGF2, another type of cell proliferative and angiogenic growth factor, safely within the core while releasing it more rapidly than FGF18. The prepared MBNs showed enlarged mesopores of about 7 nm, with a large surface area and pore volume. The protein-loading capacity of MBNs was as high as 13% when tested using cytochrome C, a model protein. The protein-loaded MBNs were smoothly incorporated within the core of the fiber by electrospinning, while preserving a fibrous morphology. The incorporation of MBNs significantly increased the apatite-forming ability and mechanical properties of the core-shell fibers. The possibility of sequential delivery of two experimental growth factors, FGF2 and FGF18, incorporated either within the core-shell fiber (FGF2) or within MBNs (FGF18), was demonstrated by the use of cytochrome C. In vitro studies using rat mesenchymal stem cells demonstrated the effects of the FGF2-FGF18 loadings: significant stimulation of cell proliferation as well as the induction of alkaline phosphate activity and cellular mineralization. An in vivo study performed on rat calvarium defects for 6 weeks demonstrated that FGF2-FGF18-loaded fiber scaffolds had significantly higher bone-forming ability, in terms of bone volume and density. The current design utilizing novel MBN nanocarriers with a core-shell structure aims to release two types of growth factors, FGF2 and FGF18, in a sequential manner, and is considered to provide a promising therapeutic scaffold platform that is effective for bone regeneration. PMID

  2. Therapeutic-designed electrospun bone scaffolds: mesoporous bioactive nanocarriers in hollow fiber composites to sequentially deliver dual growth factors.

    PubMed

    Kang, Min Sil; Kim, Joong-Hyun; Singh, Rajendra K; Jang, Jun-Hyeog; Kim, Hae-Won

    2015-04-01

    A novel therapeutic design of nanofibrous scaffolds, holding a capacity to load and deliver dual growth factors, that targets bone regeneration is proposed. Mesoporous bioactive glass nanospheres (MBNs) were used as bioactive nanocarriers for long-term delivery of the osteogenic enhancer fibroblast growth factor 18 (FGF18). Furthermore, a core-shell structure of a biopolymer fiber made of polyethylene oxide/polycaprolactone was introduced to load FGF2, another type of cell proliferative and angiogenic growth factor, safely within the core while releasing it more rapidly than FGF18. The prepared MBNs showed enlarged mesopores of about 7 nm, with a large surface area and pore volume. The protein-loading capacity of MBNs was as high as 13% when tested using cytochrome C, a model protein. The protein-loaded MBNs were smoothly incorporated within the core of the fiber by electrospinning, while preserving a fibrous morphology. The incorporation of MBNs significantly increased the apatite-forming ability and mechanical properties of the core-shell fibers. The possibility of sequential delivery of two experimental growth factors, FGF2 and FGF18, incorporated either within the core-shell fiber (FGF2) or within MBNs (FGF18), was demonstrated by the use of cytochrome C. In vitro studies using rat mesenchymal stem cells demonstrated the effects of the FGF2-FGF18 loadings: significant stimulation of cell proliferation as well as the induction of alkaline phosphate activity and cellular mineralization. An in vivo study performed on rat calvarium defects for 6 weeks demonstrated that FGF2-FGF18-loaded fiber scaffolds had significantly higher bone-forming ability, in terms of bone volume and density. The current design utilizing novel MBN nanocarriers with a core-shell structure aims to release two types of growth factors, FGF2 and FGF18, in a sequential manner, and is considered to provide a promising therapeutic scaffold platform that is effective for bone regeneration.

  3. Sulfisoxazole/cyclodextrin inclusion complex incorporated in electrospun hydroxypropyl cellulose nanofibers as drug delivery system.

    PubMed

    Aytac, Zeynep; Sen, Huseyin Sener; Durgun, Engin; Uyar, Tamer

    2015-04-01

    Herein, hydroxypropyl-beta-cyclodextrin (HPβCD) inclusion complex (IC) of a hydrophobic drug, sulfisoxazole (SFS) was incorporated in hydroxypropyl cellulose (HPC) nanofibers (HPC/SFS/HPβCD-IC-NF) via electrospinning. SFS/HPβCD-IC was characterized by DSC to investigate the formation of inclusion complex and the stoichiometry of the complex was determined by Job's plot. Modeling studies were also performed on SFS/HPβCD-IC using ab initio technique. SEM images depicted the defect free uniform fibers and confirmed the incorporation of SFS/HPβCD-IC in nanofibers did not alter the fiber morphology. XRD analyses showed amorphous distribution of SFS/HPβCD-IC in the fiber mat. Release studies were performed in phosphate buffered saline (PBS). The results suggest higher amount of SFS released from HPC/SFS/HPβCD-IC-NF when compared to free SFS containing HPC nanofibers (HPC/SFS-NF). This was attributed to the increased solubility of SFS by inclusion complexation. Sandwich configurations were prepared by placing HPC/SFS/HPβCD-IC-NF between electrospun PCL nanofibrous mat (PCL-HPC/SFS/HPβCD-IC-NF). Consequently, PCL-HPC/SFS/HPβCD-IC-NF exhibited slower release of SFS as compared with HPC/SFS/HPβCD-IC-NF. This study may provide more efficient future strategies for developing delivery systems of hydrophobic drugs. PMID:25769282

  4. Versatility of electrospinning in the fabrication of fibrous mat and mesh nanostructures of bismuth ferrite (BiFeO3) and their magnetic and photocatalytic activities.

    PubMed

    Bharathkumar, S; Sakar, M; K, Rohith Vinod; Balakumar, S

    2015-07-21

    This study demonstrates the fabrication of electrospun bismuth ferrite (BiFeO3/BFO) fiber mat and fibrous mesh nanostructures consisting of aligned and random fibers respectively. The formation of these one dimensional (1D) nanostructures was mediated by the drum and plate collectors in the electrospinning process that yielded aligned and random nanofibers of BFO respectively. The single phase and rhombohedral crystal structure of the fabricated 1D BFO nanostructures are confirmed through X-ray diffraction (XRD) studies. X-ray photoelectron spectroscopy (XPS) studies indicated that the fabricated fibers are stoichiometric BFO with native oxidation states +3. The surface texture and morphology are analyzed using the field emission scanning electron microscopy (FESEM) and high resolution transmission electron microscopy (HRTEM) techniques. The average size of fibers in mat and mesh nanostructures is found to be 200 nm and 150 nm respectively. The band gap energy of BFO mat and mesh deduced from their UV diffuse reflectance spectra (UV-DRS) was found to be 2.44 eV and 2.39 eV, respectively, which evidenced the improved visible light receptivity of BFO mesh compared to that of the mat. Magnetization studies using a super conducting quantum interference device (SQUID) magnetometer revealed the weak ferromagnetic properties of BFO mesh and mat nanostructures that could emerge due to the dimension induced suppression of cycloidal spin structures. The photocatalytic degradation properties of the fibrous mesh are found to be enhanced compared to that of the mat. This could be attributed to the reduced band gap energy and an improved semiconductor band-bending phenomenon in the mesh that favoured the transportation of excited charge carriers to the photocatalyst-dye interfaces and the production of more number of reactive species that lead to the effective degradation of the dye molecules.

  5. The Use of Nanoclays to Modify the Morphology and Photoluminescence of Electrospun Poly(9-vinylcarbazole)/Poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] Blend Fibers

    NASA Astrophysics Data System (ADS)

    Balderas, Jesús-Uriel; Falcony, Ciro; Jiménez, Gloria-Lesly; Garzón, Amanda-Stephanie; Mondragón, Margarita

    2015-04-01

    The morphology and photoluminescence properties of electrospun poly(9-vinylcarbazole) (PVK)/poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) blend fibers, which were loaded with either halloysite clay nanotubes (HNTs) or an organically modified montmorillonite (OMMT) clay, were studied by scanning electron microscopy, transmission electron microscopy, and fluorescence spectroscopy. A concentration range of 0-30 wt.% was used for the clays, while the MEH-PPV concentration was fixed at 0.5 wt.%. Both clays, especially the OMMT clay, increased the phase separation of the components in the electrospun PVK/MEH-PPV blend fibers. This was attributed to their selective localization on the polymer phases. The HNTs and OMMT clay also increased energy transfer to the lowest energy states of MEH-PPV generated during electrospinning, and modified the amount of the partially overlapping conformation of carbazole groups (p-PVK) that constrained the aggregation of the PVK chains. These changes resulted in an increased emission from p-PVK, which varied depending on the type and concentration of the clay.

  6. Greener synthesis of electrospun collagen/hydroxyapatite composite fibers with an excellent microstructure for bone tissue engineering

    PubMed Central

    Zhou, Yuanyuan; Yao, Hongchang; Wang, Jianshe; Wang, Dalu; Liu, Qian; Li, Zhongjun

    2015-01-01

    In bone tissue engineering, collagen/hydroxyapatite (HAP) fibrous composite obtained via electrospinning method has been demonstrated to support the cells’ adhesion and bone regeneration. However, electrospinning of natural collagen often requires the use of cytotoxic organic solvents, and the HAP crystals were usually aggregated and randomly distributed within a fibrous matrix of collagen, limiting their clinical potential. Here, an effective and greener method for the preparation of collagen/HAP composite fibers was developed for the first time, and this green product not only had 40 times higher mechanical properties than that previously reported, but also had an excellent microstructure similar to that of natural bone. By dissolving type I collagen in environmentally friendly phosphate buffered saline/ethanol solution instead of the frequently-used cytotoxic organic solvents, followed with the key step of desalination, co-electrospinning the collagen solution with the HAP sol, generates a collagen/HAP composite with a uniform and continuous fibrous morphology. Interestingly, the nano-HAP needles were found to preferentially orient along the longitudinal direction of the collagen fibers, which mimicked the nanostructure of natural bones. Based on the characterization of the related products, the formation mechanism for this novel phenomenon was proposed. After cross-linking with 1-ethyl-3-(3-dimethyl-aminopropyl)-1-carbodiimide hydrochloride/N-hydroxysuccinimide, the obtained composite exhibited a significant enhancement in mechanical properties. In addition, the biocompatibility of the obtained composite fibers was evaluated by in vitro culture of the human myeloma cells (U2-OS). Taken together, the process outlined herein provides an effective, non-toxic approach for the fabrication of collagen/HAP composite nanofibers that could be good candidates for bone tissue engineering. PMID:25995630

  7. Greener synthesis of electrospun collagen/hydroxyapatite composite fibers with an excellent microstructure for bone tissue engineering.

    PubMed

    Zhou, Yuanyuan; Yao, Hongchang; Wang, Jianshe; Wang, Dalu; Liu, Qian; Li, Zhongjun

    2015-01-01

    In bone tissue engineering, collagen/hydroxyapatite (HAP) fibrous composite obtained via electrospinning method has been demonstrated to support the cells' adhesion and bone regeneration. However, electrospinning of natural collagen often requires the use of cytotoxic organic solvents, and the HAP crystals were usually aggregated and randomly distributed within a fibrous matrix of collagen, limiting their clinical potential. Here, an effective and greener method for the preparation of collagen/HAP composite fibers was developed for the first time, and this green product not only had 40 times higher mechanical properties than that previously reported, but also had an excellent microstructure similar to that of natural bone. By dissolving type I collagen in environmentally friendly phosphate buffered saline/ethanol solution instead of the frequently-used cytotoxic organic solvents, followed with the key step of desalination, co-electrospinning the collagen solution with the HAP sol, generates a collagen/HAP composite with a uniform and continuous fibrous morphology. Interestingly, the nano-HAP needles were found to preferentially orient along the longitudinal direction of the collagen fibers, which mimicked the nanostructure of natural bones. Based on the characterization of the related products, the formation mechanism for this novel phenomenon was proposed. After cross-linking with 1-ethyl-3-(3-dimethyl-aminopropyl)-1-carbodiimide hydrochloride/N-hydroxysuccinimide, the obtained composite exhibited a significant enhancement in mechanical properties. In addition, the biocompatibility of the obtained composite fibers was evaluated by in vitro culture of the human myeloma cells (U2-OS). Taken together, the process outlined herein provides an effective, non-toxic approach for the fabrication of collagen/HAP composite nanofibers that could be good candidates for bone tissue engineering.

  8. Greener synthesis of electrospun collagen/hydroxyapatite composite fibers with an excellent microstructure for bone tissue engineering.

    PubMed

    Zhou, Yuanyuan; Yao, Hongchang; Wang, Jianshe; Wang, Dalu; Liu, Qian; Li, Zhongjun

    2015-01-01

    In bone tissue engineering, collagen/hydroxyapatite (HAP) fibrous composite obtained via electrospinning method has been demonstrated to support the cells' adhesion and bone regeneration. However, electrospinning of natural collagen often requires the use of cytotoxic organic solvents, and the HAP crystals were usually aggregated and randomly distributed within a fibrous matrix of collagen, limiting their clinical potential. Here, an effective and greener method for the preparation of collagen/HAP composite fibers was developed for the first time, and this green product not only had 40 times higher mechanical properties than that previously reported, but also had an excellent microstructure similar to that of natural bone. By dissolving type I collagen in environmentally friendly phosphate buffered saline/ethanol solution instead of the frequently-used cytotoxic organic solvents, followed with the key step of desalination, co-electrospinning the collagen solution with the HAP sol, generates a collagen/HAP composite with a uniform and continuous fibrous morphology. Interestingly, the nano-HAP needles were found to preferentially orient along the longitudinal direction of the collagen fibers, which mimicked the nanostructure of natural bones. Based on the characterization of the related products, the formation mechanism for this novel phenomenon was proposed. After cross-linking with 1-ethyl-3-(3-dimethyl-aminopropyl)-1-carbodiimide hydrochloride/N-hydroxysuccinimide, the obtained composite exhibited a significant enhancement in mechanical properties. In addition, the biocompatibility of the obtained composite fibers was evaluated by in vitro culture of the human myeloma cells (U2-OS). Taken together, the process outlined herein provides an effective, non-toxic approach for the fabrication of collagen/HAP composite nanofibers that could be good candidates for bone tissue engineering. PMID:25995630

  9. Regulated release of a novel non-viral gene delivery vector from electrospun coaxial fiber mesh scaffolds

    NASA Astrophysics Data System (ADS)

    Saraf, Anita

    The development of novel strategies for tissue engineering entails the evolution of biopolymers into multifunctional constructs that can support the proliferation of cells and stimulate their differentiation into functional tissues. With that in mind, biocompatible polymers were fabricated into a novel gene delivery agent as well as three dimensional scaffolds that act as reservoirs and controlled release constructs. To fabricate a novel gene delivery agent a commercially available cationic polymer, poly(ethylenimine), PEI, was chemically conjugated to a ubiquitous glycosaminoglycan, hyaluronic acid (HA). The novel polymer, PEI-HA, had significantly reduced toxicity and improved transfection efficiency with multipotent human mesenchymal stem cells. This transfection efficiency could further be modulated by changing the concentration of sodium chloride and temperature used to assemble PEI-HA/DNA complexes. To facilitate the regulated delivery of these complexes in the context of tissue engineering, an emerging technology for scaffold fabrication, coaxial electrospinning was adapted to include PEI-HA and plasmid DNA within the scaffold fibers. Initially, a factorial design was employed to assess the influence of processing parameters in the absence of gene delivery vectors and plasmids. The study elucidated the role of sheath polymer concentration and core polymer concentration and molecular weight and the presence of sodium chloride on fiber diameters and morphologies. Subsequently, PEI-HA and plasmid DNA were entrapped within the sheath and core compartments of these fibers and the influence of processing parameters was assessed in the context of fiber diameter, release kinetics and transfection efficiency over a period of 60 days. The release of PEI-HA was found to be dependent upon the loading dose of the vector and plasmid. However, the transfection efficiency correlated to the core polymer properties, concentration and molecular weight. The processing

  10. The effect of thiolated additives on the properties of wheat gluten based plastics, aqueous solutions and electrospun fibers

    NASA Astrophysics Data System (ADS)

    Dong, Jing

    Wheat gluten (WG) is a promising substitute for petroleum-based plastics due to its unique ability to form a cohesive blend with viscoelastic properties once plasticized. Previous work blending WG with thiolated poly(vinyl alcohol) (TPVA) showed that both the strength and elongation of compression molded native WG bars can be improved via thiol/disulfide interchange reactions between WG and TPVA. In this study, the morphology of WG/TPVA blends was investigated by atomic force (AFM) and transmission electron microscopy (TEM), as well as by modulated dynamic scanning calorimetry (MDSC). Consistent with our earlier results, AFM and TEM imaging clearly indicated that TPVA is much more compatible with WG compared with poly(vinyl alcohol) (PVA) although there are still two phases in the blend: one WG rich phase and another TPVA rich phase. TPVA was also blended with WG in an aqueous solvent (1/1 (v/v) water/1-propanol mixture) to improve its solubility and spinnability. Control experiments were conducted with PVA and dithiothreitol (DTT) for comparison purposes. The concentration and the thiolation level of TPVA were also varied to explore the parameter space. The interactions of thiol groups from TPVA and soluble WG were found to be important during electrospinning. The fiber diameter became more uniform and the fiber quality increased very noticeably when TPVA was included. Furthermore, the time-dependent rheology behaviors of TPVA/WG and DTT/WG electrospinning solutions were investigated by using steady shear sweeps, oscillatory frequency sweeps, SE-HPLC and free -SH content determination. A two-step mechanism of interaction was proposed for DTT/WG and TPVA/WG solutions based on current results and other earlier studies. In comparison with WG and PVA/WG solutions, the reduction and reformation of disulfide linkages in both TPVA/WG and DTT/WG solutions were believed to play a key role in determining the rheological properties and molecular weight distribution of WG

  11. Electrospun Nanofibrous Sheets for Selective Cell Capturing in Continuous Flow in Microchannels.

    PubMed

    Son, Young Ju; Kang, Jihyun; Kim, Hye Sung; Yoo, Hyuk Sang

    2016-03-14

    Electrospun nanofibrous meshes were surface-modified for selective capturing of specific cells from a continuous flow in PDMS microchannels. We electrospun nanofibrous mats composed of poly(ε-carprolactone) (PCL) and amine-functionalized block copolymers composed of PCL and poly(ethylenimine) (PEI). A mixture of biotinylated PEG and blunt PEG was chemically tethered to the nanofibrous mats via the surface-exposed amines on the mat. The degree of biotinylation was fluorescently and quantitatively assayed for confirming the surface-biotinylation levels for avidin-specific binding. The incorporation level of avidin gradually increased when the blend ratio of biotinylated PEG on the mat increased, confirming the manipulated surfaces with various degree of biotinylation. Biotinylated cells were incubated with avidin-coated biotinylated mats and the specific binding of biotinylated cells was monitored in a microfluidic channel with a continuous flow of culture medium, which suggests efficient and selective capturing of the biotinylated cells on the nanofibrous mat. PMID:26812501

  12. Electrospun Cu/Sn/C nanocomposite fiber anodes with superior usable lifetime for lithium- and sodium-ion batteries.

    PubMed

    Kim, Jae-Chan; Kim, Dong-Wan

    2014-11-01

    Cu/Sn/C composite nanofibers were synthesized by using dual-nozzle electrospinning and subsequent carbonization. The composite nanofibers are a homogeneous amorphous matrix comprised of Cu, Sn, and C with a trace of crystalline Sn. The Li- and Na-ion storage performance of the Cu/Sn/C fiber electrodes were investigated by using cyclic voltammetry, galvanostatic cycling, and electrochemical impedance spectroscopy. Excellent, stable cycling performance indicates capacities of 490 and 220 mA h g(-1) for Li-ion (600 cycles) and Na-ion (200 cycles) batteries, respectively. This is a significant improvement over other reported Sn/C nanocomposite devices. These superior electrochemical properties could be attributed to the advantages of incorporating one-dimensional nanostructures into the electrodes, such as short electron diffusion lengths, large specific surface areas, ideal homogeneous structures for buffering volume changes, and better electronic conductivity that results from the amorphous copper and carbon matrix. PMID:25225075

  13. A Comparison of Electrospun Polymers Reveals Poly(3-Hydroxybutyrate) Fiber as a Superior Scaffold for Cardiac Repair

    PubMed Central

    Castellano, Delia; Blanes, María; Marco, Bruno; Cerrada, Inmaculada; Ruiz-Saurí, Amparo; Pelacho, Beatriz; Araña, Miriam; Montero, Jose A.; Cambra, Vicente; Prosper, Felipe

    2014-01-01

    The development of biomaterials for myocardial tissue engineering requires a careful assessment of their performance with regards to functionality and biocompatibility, including the immune response. Poly(3-hydroxybutyrate) (PHB), poly(e-caprolactone) (PCL), silk, poly-lactic acid (PLA), and polyamide (PA) scaffolds were generated by electrospinning, and cell compatibility in vitro, and immune response and cardiac function in vitro and in vivo were compared with a noncrosslinked collagen membrane (Col) control material. Results showed that cell adhesion and growth of mesenchymal stem cells, cardiomyocytes, and cardiac fibroblasts in vitro was dependent on the polymer substrate, with PHB and PCL polymers permitting the greatest adhesion/growth of cells. Additionally, polymer substrates triggered unique expression profiles of anti- and pro-inflammatory cytokines in human peripheral blood mononuclear cells. Implantation of PCL, silk, PLA, and PA patches on the epicardial surface of healthy rats induced a classical foreign body reaction pattern, with encapsulation of polymer fibers and induction of the nonspecific immune response, whereas Col and PHB patches were progressively degraded. When implanted on infarcted rat heart, Col, PCL, and PHB reduced negative remodeling, but only PHB induced significant angiogenesis. Importantly, Col and PHB modified the inflammatory response to an M2 macrophage phenotype in cardiac tissue, indicating a more beneficial reparative process and remodeling. Collectively, these results identify PHB as a superior substrate for cardiac repair. PMID:24564648

  14. Silane crosslinking of electrospun poly (lactic acid)/nanocrystalline cellulose bionanocomposite.

    PubMed

    Rahmat, M; Karrabi, M; Ghasemi, I; Zandi, M; Azizi, H

    2016-11-01

    Biodegradable nanofibrous mats fabricated by electrospinning are commonly used in tissue engineering, however, lack of essential mechanical properties of such nanofibers is a challenging issue. In this work, vinyltrimethoxysilane (VTMS) was grafted onto poly (lactic acid) (PLA) and the silane grafted PLA was subsequently applied in electrospinning process. Electrospun nanofibrous mats based on PLA/nanocrystalline cellulose (NCC) and PLA-g-silane/NCC nanocomposites were fabricated and immersed in hot water (70°C) for crosslinking of silane grafted PLA. It was found that introducing NCC to the samples cause to reduction in fiber diameter and the other hand the silane crosslinking of PLA increase the mean fiber diameter. DSC thermograms also revealed that silane grafting caused a reduction in mobility of polymer segments, and consequently reduction of crystallinity. On the contrary, the NCC in the PLA-g-silane samples effectively influenced the crystal nucleation, while in the PLA nanofibers the nucleation was lower. The impact of NCC on tensile strength enhancement of samples was notable. The results suggested that the chemical crosslinking remarkably improves the mechanical properties of PLA nanofibers. Furthermore, biocompatibility of such modified nanofibers was also evaluated through cytotoxicity results, therefore the modified PLA nanocomposite can be considered as a practical candidate for hard tissue engineering applications. PMID:27524034

  15. Silane crosslinking of electrospun poly (lactic acid)/nanocrystalline cellulose bionanocomposite.

    PubMed

    Rahmat, M; Karrabi, M; Ghasemi, I; Zandi, M; Azizi, H

    2016-11-01

    Biodegradable nanofibrous mats fabricated by electrospinning are commonly used in tissue engineering, however, lack of essential mechanical properties of such nanofibers is a challenging issue. In this work, vinyltrimethoxysilane (VTMS) was grafted onto poly (lactic acid) (PLA) and the silane grafted PLA was subsequently applied in electrospinning process. Electrospun nanofibrous mats based on PLA/nanocrystalline cellulose (NCC) and PLA-g-silane/NCC nanocomposites were fabricated and immersed in hot water (70°C) for crosslinking of silane grafted PLA. It was found that introducing NCC to the samples cause to reduction in fiber diameter and the other hand the silane crosslinking of PLA increase the mean fiber diameter. DSC thermograms also revealed that silane grafting caused a reduction in mobility of polymer segments, and consequently reduction of crystallinity. On the contrary, the NCC in the PLA-g-silane samples effectively influenced the crystal nucleation, while in the PLA nanofibers the nucleation was lower. The impact of NCC on tensile strength enhancement of samples was notable. The results suggested that the chemical crosslinking remarkably improves the mechanical properties of PLA nanofibers. Furthermore, biocompatibility of such modified nanofibers was also evaluated through cytotoxicity results, therefore the modified PLA nanocomposite can be considered as a practical candidate for hard tissue engineering applications.

  16. Electrospun nanofiber layers with incorporated photoluminescence indicator for chromatography and detection of ultraviolet-active compounds.

    PubMed

    Kampalanonwat, Pimolpun; Supaphol, Pitt; Morlock, Gertrud E

    2013-07-19

    For the first time, electrospun nanofiber phases were fabricated with manganese-activated zinc silicate as photoluminescent indicator (UV254) to transfer and enlarge its application to the field of UV-active compounds. By integration of such an indicator, UV-active compounds got visible on the chromatogram. The separation of 7 preservatives and a beverage sample were studied on the novel luminescent polyacrylonitrile layers. The mat thickness and mean fiber diameters were calculated for additions of different UV254 indicator concentrations. The separation efficiency on the photoluminescent layers was characterized by comparison to HPTLC layers and calculation of the plate numbers and resolutions. Some benefits were the reduction in migration distance (3cm), migration time (12min), analyte (10-nL volumes) and mobile phase volumes (1mL). As ultrathin stationary phase, such layers are suited for their integration into the Office Chromatography concept. For the first time, electrospun nanofiber layers were hyphenated with mass spectrometry and the confirmation of compounds was successfully performed using the elution-head based TLC-MS Interface.

  17. Electrospun Nanofibers for Neural and Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Xia, Younan

    2009-03-01

    Electrospinning has been exploited for almost one century to process polymers and other materials into nanofibers with controllable compositions, diameters, porosities, and porous structures for a variety of applications. Owing to its small size, high porosity, and large surface area, a nonwoven mat of electrospun nanofibers can serve as an ideal scaffold to mimic the extra cellular matrix for cell attachment and nutrient transportation. The nanofiber itself can also be functionalized through encapsulation or attachment of bioactive species such as extracellular matrix proteins, enzymes, and growth factors. In addition, the nanofibers can be further assembled into a variety of arrays or architectures by manipulating their alignment, stacking, or folding. All these attributes make electrospinning a powerful tool for generating nanostructured materials for a range of biomedical applications that include controlled release, drug delivery, and tissue engineering. This talk will focus on the use of electrospun nanofibers as scaffolds for neural and bone tissue engineering.

  18. A Facile Approach for the Mass Production of Submicro/Micro Poly (Lactic Acid) Fibrous Mats and Their Cytotoxicity Test towards Neural Stem Cells

    PubMed Central

    2016-01-01

    Despite many of the studies being conducted, the electrospinning of poly (lactic acid) (PLA), dissolved in its common solvents, is difficult to be continuously processed for mass production. This is due to the polymer solution droplet drying. Besides, the poor stretching capability of the polymer solution limits the production of small diameter fibers. To address these issues, we have examined the two following objectives: first, using an appropriate solvent system for the mass production of fibrous mats with fine-tunable fiber diameters; second, nontoxicity of the mats towards Neural Stem Cell (NSC). To this aim, TFA (trifluoroacetic acid) was used as a cosolvent, in a mixture with DCM (dichloromethane), and the solution viscosity, surface tension, electrical conductivity, and the continuity of the electrospinning process were compared with the solutions prepared with common single solvents. The binary solvent facilitated PLA electrospinning, resulting in a long lasting, stable electrospinning condition, due to the low surface tension and high conductivity of the binary-solvent system. The fiber diameter was tailored from nano to micro by varying effective parameters and examined by scanning electron microscopy (SEM) and image-processing software. Laminin-coated electrospun mats supported NSC expansion and spreading, as examined using AlamarBlue assay and fluorescent microscopy, respectively.

  19. A Facile Approach for the Mass Production of Submicro/Micro Poly (Lactic Acid) Fibrous Mats and Their Cytotoxicity Test towards Neural Stem Cells

    PubMed Central

    2016-01-01

    Despite many of the studies being conducted, the electrospinning of poly (lactic acid) (PLA), dissolved in its common solvents, is difficult to be continuously processed for mass production. This is due to the polymer solution droplet drying. Besides, the poor stretching capability of the polymer solution limits the production of small diameter fibers. To address these issues, we have examined the two following objectives: first, using an appropriate solvent system for the mass production of fibrous mats with fine-tunable fiber diameters; second, nontoxicity of the mats towards Neural Stem Cell (NSC). To this aim, TFA (trifluoroacetic acid) was used as a cosolvent, in a mixture with DCM (dichloromethane), and the solution viscosity, surface tension, electrical conductivity, and the continuity of the electrospinning process were compared with the solutions prepared with common single solvents. The binary solvent facilitated PLA electrospinning, resulting in a long lasting, stable electrospinning condition, due to the low surface tension and high conductivity of the binary-solvent system. The fiber diameter was tailored from nano to micro by varying effective parameters and examined by scanning electron microscopy (SEM) and image-processing software. Laminin-coated electrospun mats supported NSC expansion and spreading, as examined using AlamarBlue assay and fluorescent microscopy, respectively. PMID:27699177

  20. Plasma assisted synthesis of hollow nanofibers using electrospun sacrificial templates

    NASA Astrophysics Data System (ADS)

    Rahmathullah, Aflal M.; Jason Robinette, E.; Chen, Hong; Elabd, Yossef A.; Palmese, Giuseppe R.

    2007-12-01

    In this work, we describe the synthesis of nanostructured polymeric materials of controlled tubular geometries using oxygen plasma and polysiloxane-grafting onto electrospun fiber sacrificial templates. The fibers were characterized using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) to determine the extent of grafting, graft chemistry and the influence of plasma treatment. Scanning electron microscopy (SEM) was used to determine the morphology and size of the electrospun fibers and nanotubes. The average diameter of the electrospun fibers employed ranged between 300 nm and 1500 nm. The micrographs revealed differences that are dependent on the type of grafting chemistry as well as plasma treatment times. The template synthesis of polysiloxane nanotubes using polyester track-etched membranes also shows that the technique is applicable to different substrates.

  1. Co-axial electrospun polystyrene/polyurethane fibres for oil collection from water surface

    NASA Astrophysics Data System (ADS)

    Lin, Jinyou; Tian, Feng; Shang, Yanwei; Wang, Fujun; Ding, Bin; Yu, Jianyong; Guo, Zhi

    2013-03-01

    The pollution arising from oil spills is a matter of great concern due to its damaging impacts on the ecological environment, which has created a tremendous need to find more efficient materials for oil spill cleanup. In this work, we reported a sorbent for oil soak-up from a water surface with a high sorption capacity, good selectivity, and excellent reusability based on the hydrophobic-oleophilic fibrous mats that were fabricated via co-axial electrospinning polystyrene (PS) solution as the shell solution and polyurethane (PU) solution as the core solution. The fine structures of as-prepared fibers were regulated by manipulating the spinning voltages, core solution concentrations, and solvent compositions in shell solutions, which were also characterized by field emission scanning electron microscopy, transmission electron microscopy, nitrogen adsorption method, and synchrotron radiation small-angle X-ray scattering. The effects of inter-fiber voids and intra-fiber porosity on oil sorption capacities were well studied. A comparison of oil sorption capacity for the single fiber with different porous structures was also investigated with the help of scanning transmission X-ray microscopy. The results showed that the sorption capacities of the as-prepared sorbent with regards to motor oil and sunflower seed oil can be 64.40 and 47.48 g g-1, respectively, approximately 2-3 times that of conventional polypropylene (PP) fibers for these two same oils. Even after five sorption cycles, a comparable oil sorption capacity with PP fibers was still maintained, exhibiting an excellent reusability. We believe that the composite PS-PU fibrous mats have a great potential application in wastewater treatment, oil accident remediation and environmental protection.The pollution arising from oil spills is a matter of great concern due to its damaging impacts on the ecological environment, which has created a tremendous need to find more efficient materials for oil spill cleanup. In

  2. Shear adhesion strength of aligned electrospun nanofibers.

    PubMed

    Najem, Johnny F; Wong, Shing-Chung; Ji, Guang

    2014-09-01

    Inspiration from nature such as insects' foot hairs motivates scientists to fabricate nanoscale cylindrical solids that allow tens of millions of contact points per unit area with material substrates. In this paper, we present a simple yet robust method for fabricating directionally sensitive shear adhesive laminates. By using aligned electrospun nylon-6, we create dry adhesives, as a succession of our previous work on measuring adhesion energies between two single free-standing electrospun polymer fibers in cross-cylinder geometry, randomly oriented membranes and substrate, and peel forces between aligned fibers and substrate. The synthetic aligned cylindrical solids in this study are electrically insulating and show a maximal Mode II shear adhesion strength of 27 N/cm(2) on a glass slide. This measured value, for the purpose of comparison, is 270% of that reported from gecko feet. The Mode II shear adhesion strength, based on a commonly known "dead-weight" test, is 97-fold greater than the Mode I (normal) adhesion strength of the same. The data indicate a strong shear binding on and easy normal lifting off. Anisotropic adhesion (Mode II/Mode I) is pronounced. The size and surface boundary effects, crystallinity, and bending stiffness of fibers are used to understand these electrospun nanofibers, which vastly differ from otherwise known adhesive technologies. The anisotropic strength distribution is attributed to a decreasing fiber diameter and an optimized laminate thickness, which, in turn, influences the bending stiffness and solid-state "wettability" of points of contact between nanofibers and surface asperities.

  3. Highly Stretchable Strain Sensors Using an Electrospun Polyurethane Nanofiber/Graphene Composite.

    PubMed

    Hu, Daqing; Wang, Qinghe; Yu, Jixian; Hao, Wentao; Lu, Hongbo; Zhang, Guobing; Wang, Xianghua; Qiu, Longzhen

    2016-06-01

    A highly flexible and stretchable strain sensor has been prepared by coating chemical reduction of graphene oxide on electrospun polyurethane nanofiber mats. The sensor exhibits an ohmic behavior regardless of applied strains and the current monotonically increases with the increase of the tensile strain. The morphology and stability of electrospun polyurethane nanocomposite mats were also studied. The flexible and stretchable strain sensor has great potential for practical application such as efficient human-motion detection. This cheap and simple process of graphene layer provides an effective fabrication for graphene stretchable electronic devices and strain sensors due to excellent stability and electrical proper. PMID:27427641

  4. Fabrication and mechanical characterization of 3D electrospun scaffolds for tissue engineering.

    PubMed

    Wright, L D; Young, R T; Andric, T; Freeman, J W

    2010-10-01

    Electrospinning is a polymer processing technique that produces fibrous structures comparable to the extracellular matrix of many tissues. Electrospinning, however, has been severely limited in its tissue engineering capabilities because this technique has produced few three-dimensional structures. Sintering of electrospun materials provides a method to fabricate unique architectures and allow much larger structures to be made. Electrospun mats were sintered into strips and cylinders, and their tensile and compressive mechanical properties were measured. In addition, electrospun materials with salt pores (salt embedded within the material and then leached out) were fabricated to improve porosity of the electrospun materials for tissue engineering scaffolds. Sintered electrospun poly(D,L-lactide) and poly(L-lactide) (PDLA/PLLA) materials have higher tensile mechanical properties (modulus: 72.3 MPa, yield: 960 kPa) compared to unsintered PLLA (modulus: 40.36 MPa, yield: 675.5 kPa). Electrospun PDLA/PLLA cylinders with and without salt-leached pores had compressive moduli of 6.69 and 26.86 MPa, respectively, and compressive yields of 1.36 and 0.56 MPa, respectively. Sintering of electrospun materials is a novel technique that improves electrospinning application in tissue engineering by increasing the size and types of electrospun structures that can be fabricated.

  5. 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.

    PubMed

    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. PMID:26460282

  6. 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.

    PubMed

    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.

  7. Method for Coating a Tow with an Electrospun Nanofiber

    NASA Technical Reports Server (NTRS)

    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.

  8. Antimicrobial application of nanofibrous mats self-assembled with chitosan and epigallocatechin gallate.

    PubMed

    Tian, Jing; Tu, Hu; Shi, Xiaowen; Wang, Xiaoying; Deng, Hongbing; Li, Bin; Du, Yumin

    2016-09-01

    Cellulose electrospun nanofibrous mats coated with bilayers of chitosan (CS) and epigallocatechin gallate (EGCG) or with bilayers of CS-rectorite (REC) composite (CS-REC) and EGCG were fabricated via layer-by-layer (LBL) self-assembly technique. LBL-structured cellulose nanofibers still maintained three-dimension fiber structure according to the observation from scanning electron microscopy images. The average diameter of nanofibers were enlarged with the addition of REC. X-ray photoelectron spectroscopy results confirmed the deposition of CS and CS-REC onto the corresponding mats. The tensile strength and rate of elongation at break of LBL-structured nanofibers had no difference from those of uncoated nanofibers. The encapsulation efficiency and loading capacity of nanofibers were enhanced in the presence of REC. In addition the in-vitro cumulative release profiles of EGCG indicate that the addition of REC delayed the release of EGCG. Antimicrobial assay demonstrated the inhibitory effects of CS and EGCG on the growth of Staphylococcus aureus. Meanwhile the CS-REC composites improved the antimicrobial effects of CS and EGCG by adsorption of bacteria to the surface of REC then enhancement of exposure of bacteria to EGCG and the matrix of CS.

  9. Annealing polymer nanofibrous nanocomposite mats via photothermal heating: effects on overall crystallinity, morphology, and mechanical properties

    NASA Astrophysics Data System (ADS)

    Gorga, Russell; Clarke, Laura; Bochinski, Jason; Viswanath, Vidya; Maity, Somsubhra

    2014-03-01

    Metal nanoparticles embedded within polymeric systems can be made to act as localized heat sources thereby aiding in-situ polymer processing. This is made possible by the surface plasmon resonance mediated photothermal effect of metal nanoparticles, wherein incident light absorbed by the nanoparticle generates a non-equilibrium electron distribution which subsequently transfers this energy into the surrounding medium, resulting in a temperature increase in the immediate region around the particle. Here we demonstrate this effect in polyethylene oxide-gold nanoparticle electrospun nanofibrous mats, which have been annealed at temperatures above the glass transition. A non-contact temperature measurement technique utilizing embedded fluorophores (perylene) has been used to monitor the average temperature within samples. The effect of annealing methods (conventional and photothermal) and annealing conditions (temperature and time) on the fiber morphology, overall crystallinity, and mechanical properties is discussed. In conclusion we demonstrate that the specificity of plasmonic heating coupled with the inside-outside approach of annealing presents a unique tool to improve crystallinity, and therefore mechanical properties, of the polymer mats while maintaining the unique nanofibrous morphologies. Supported by the National Science Foundation (CMMI-1069108).

  10. Archean Microbial Mat Communities

    NASA Astrophysics Data System (ADS)

    Tice, Michael M.; Thornton, Daniel C. O.; Pope, Michael C.; Olszewski, Thomas D.; Gong, Jian

    2011-05-01

    Much of the Archean record of microbial communities consists of fossil mats and stromatolites. Critical physical emergent properties governing the evolution of large-scale (centimeters to meters) topographic relief on the mat landscape are (a) mat surface roughness relative to the laminar sublayer and (b) cohesion. These properties can be estimated for fossil samples under many circumstances. A preliminary analysis of Archean mat cohesion suggests that mats growing in shallow marine environments from throughout this time had cohesions similar to those of modern shallow marine mats. There may have been a significant increase in mat strength at the end of the Archean.

  11. Microscopy and supporting data for osteoblast integration within an electrospun fibrous network

    PubMed Central

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

    2015-01-01

    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. PMID:26693511

  12. Functionalized nanowires from electrospun polymer nanofibers

    NASA Astrophysics Data System (ADS)

    Ruiz, A.; Vega, E.; Katiyar, R.; Valentin, R.

    2007-05-01

    The ability to pattern materials in three dimensions is critical for several emerging technologies, including photonics, μfluidics, MEMS, and biomaterials. Electrospinning allows one to functionalized and rapidly fabricate materials in complex three-dimensional shapes without the need for expensive tooling, dies, or lithographic masks. Here, recent advances in functionalization techniques are reviewed with an emphasis on the push toward patterning finer feature sizes. Effects of material and process parameters on the diameter of electrospun Poly Ethylene Oxide (PEO) fibers were experimentally investigated. Experiments were conducted at the settings of solution flow rate, voltage and the collector distance. It also imparted the evaluation of the significance of each parameter on the resultant fiber diameter. All the factors were found statistically significant in the production of nanoscale fibers. Opportunities and challenges associated with electrospinning of polyacrylonitrile fibers are also highlighted.

  13. Near-Edge X-ray Absorption Fine Structure Studies of Electrospun Poly(dimethylsiloxane)/Poly (methyl methacrylate)/Multiwall Carbon Nanotube Composites

    PubMed Central

    Winter, A. Douglas; Larios, Eduardo; Alamgir, Faisal M.; Jaye, Cherno; Fischer, Daniel; Campo, Eva M.

    2014-01-01

    This work describes the near conduction band edge structure of electrospun mats of MWCNT-PDMS-PMMA by near edge X-Ray absorption fine structure (NEXAFS) spectroscopy. Effects of adding nanofillers of different sizes were addressed. Despite observed morphological variations and inhomogeneous carbon nanotube distribution, spun mats appeared homogeneous under NEXAFS analysis. Spectra revealed differences in emissions from glancing and normal spectra; which may evidence phase separation within the bulk of the micron-size fibers. Further, dichroic ratios show polymer chains did not align, even in the presence of nanofillers. Addition of nanofillers affected emissions in the C-H, C=O and C-C regimes, suggesting their involvement in interfacial matrix-carbon nanotube bonding. Spectral differences at glancing angles between pristine and composite mats suggest that geometric conformational configurations are taking place between polymeric chains and carbon nanotubes. These differences appear to be carbon nanotube-dimension dependent, and are promoted upon room temperature mixing and shear flow during electrospinning. CH-π bonding between polymer chains and graphitic walls, as well as H-bonds between impurities in the as-grown CNTs and polymer pendant groups are proposed bonding mechanisms promoting matrix conformation. PMID:24308286

  14. Enhanced mechanical properties and cytocompatibility of electrospun poly(L-lactide) composite fiber membranes assisted by polydopamine-coated halloysite nanotubes

    NASA Astrophysics Data System (ADS)

    Luo, Chuang; Zou, Ziping; Luo, Binghong; Wen, Wei; Li, Huihua; Liu, Mingxian; Zhou, Changren

    2016-04-01

    To improve the dispersion and interfacial interaction between halloysite nanotubes (HNTs) and poly(L-lactide) (PLLA) matrix, and hence to increase the mechanical properties and cytocompatibility of the HNTs/PLLA composite, a facile approach was developed to prepare polydopamine-coated HNTs (D-HNTs) by the self-polymerization of dopamine (DOPA), and then HNTs and D-HNTs were further introduced into PLLA matrix to fabricate HNTs/PLLA and D-HNTs/PLLA fiber membranes based on electrospinning technique. The successful immobilization of the polydopamine (PDOPA) coating on the surfaces of HNTs was confirmed, and such PDOPA coating played an important role in improving the interfacial interaction between the nanotubes and PLLA matrix. The D-HNTs were dispersed in the matrix more uniformly than untreated HNTs, and relative smooth and uniform fiber were obtained for the D-HNTs/PLLA fiber membrane. As a result, the tensile strength and modulus of the D-HNTs/PLLA fiber membrane were obviously superior to those of the HNTs/PLLA fiber membrane. Cell culture results revealed that D-HNTs/PLLA fiber membrane was more effectively to promote MC3T3-E1 cells adhesion and proliferation than neat PLLA and HNTs/PLLA fiber membrane.

  15. A preliminary discourse on adhesion of nanofibers derived from electrospun polymers

    NASA Astrophysics Data System (ADS)

    Chen, Pei

    To bio-mimic gecko's foot hair, which possess high adhesion strength and can be re- usable for lifetime, fibrous membranes are fabricated by electrospinning to provide sufficient adhesion energy. Shaft-loaded blister test (SLBT) is firstly used to measure the work of adhesion between electrospun membrane and rigid substrate. Poly(vinylidene fluoride) (PVDF) were electrospun with an average fiber diameter of 333+/-59 nm. Commercial cardboard with inorganic coating was used to provide a model substrate for adhesion tests. In SLBT, the elastic response PVDF was analyzed and its adhesion energy measured. FEA model with cohesive layer is developed to evaluate the experiment results. The results show SLBT presented a viable methodology for evaluating the adhesion energy of electrospun polymer fabrics. Electrospun membranes with different fiber diameter are tested for their distinctive adhesion property. Five sets of PVDF membranes with different fiber diameters (from 201 +/- 86 nm to 2724 +/- 587 nm) are electrospun for size effect evaluation. Obtaining testing results from SLBT adhesion test, adhesion energy ranges from 258.83 +/- 43.54 mJ/m2 to 8.06 +/- 0.71 mJ/m2. Significant size effect is observed, and electrospun membrane composing from finer fibers possesses greater adhesion energy. Thickness effect is also evaluated. By stacking multiple layers of electrospun membrane together, membrane samples with different thickness are produced. Test results illustrate thick membrane trends to debond easier than thin membrane. After considering the characteristic of electrospun membrane, the effect of substrate is also evaluated. One approach is made by substituting SiC substrates with different roughness for cardboard substrate. The grit size of the SiC substrates varies from 5 mum to 68 mum. A correlation between adhesion energy and mean peak and valley roughness (Rz) is established from mechanical interlocking theory. The other approach is comparing adhesion energies if

  16. Electrospun mixed oxide photocatalysts to decompose dyes in water

    NASA Astrophysics Data System (ADS)

    Divya, Sherlyn

    In this work, four catalysts have been studied for their photocatalytic efficiency by testing each with methylene blue dye solution. Three catalysts were synthesized by the electrospinning method and then compared with the fourth commercially available catalyst for their photocatalytic activity. The basic metal oxide studied was titanium dioxide. Nanocomposite mats of pure titania, copper doped titania and copper doped degussa P25 titania, were synthesized using the electrospinning method. The pure titania and copper doped titania nanocomposites possessed the anatase phase which was obtained by annealing the as-spun nanocomposites at 4500C. All the catalysts were analyzed for their photocatalytic activity both under ultra-violet light and under visible light. The aim of this work was to synthesize titania photocatalysts, demonstrate their photocatalytic activity with methylene blue solution under UV-light and visible light and compare their activities with the commercial titanium dioxide (degussa P25). It is important to synthesize visible light active photocatalysts as these could be activated under a wide spectrum of natural sunlight unlike the degussa titanium dioxide. Doping was incorporated in order to narrow the band gap energy of the photocatalyst for achieving higher efficiency especially under visible light irradiation. The morphology and size of the synthesized photocatalysts were studied by characterizing them with Scanning Electron Microscopy, Energy Dispersive X-Ray Spectroscopy, Transmission Electron Microscopy and X-Ray Diffraction. The photocatalytic activity tests were carried out using UV-Vis Spectroscopy. It was found that the electrospun pure titania and copper doped titania fibers were activated under the visible light spectrum unlike the degussa titanium dioxide. The copper doped titania provided to be the most efficient photocatalyst under visible light radiation and the importance of this finding can be extended for treating industrial

  17. Mat2exo

    SciTech Connect

    2012-09-11

    MAT2EXO is a program which translates mesh data from Matlab mat-file format to Exodus II format. This tool is the inverse of the commonly used tool exo2mat which translates Exodus II data to the Matlab mat-file format. These tools provide a means for preprocessing an Exodus II model file or postprocessing an Exodus II results file using Matlab

  18. Engineering the Microstructure of Electrospun Fibrous Scaffolds by Microtopography

    PubMed Central

    Cheng, Qian; Lee, Benjamin L.-P.; Komvopoulos, Kyriakos; Li, Song

    2013-01-01

    Controlling the structure and organization of electrospun fibers is desirable for fabricating scaffolds and materials with defined microstructures. However, the effects of microtopography on the deposition and, in turn, the organization of the electrospun fibers are not well understood. In this study, conductive polydimethylsiloxane (PDMS) templates with different micropatterns were fabricated by combining photolithography, silicon wet etching, and PDMS molding techniques. The fiber organization was varied by fine-tuning the microtopography of the electrospinning collector. Fiber conformity and alignment were influenced by the depth and the slope of microtopography features, resulting in scaffolds comprising either an array of microdomains with different porosity and fiber alignment or an array of microwells. Microtopography affected the fiber organization for hundreds of micrometers below the scaffold surface, resulting in scaffolds with distinct surface properties on each side. In addition, the fiber diameter was also affected by the fiber conformity. The effects of the fiber arrangement in the scaffolds on the morphology, migration, and infiltration of cells were examined by in vitro and in vivo experiments. Cell morphology and organization were guided by the fibers in the microdomains, and cell migration was enhanced by the aligned fibers and the three-dimensional scaffold structure. Cell infiltration was correlated with the microdomain porosity. Microscale control of the fiber organization and the porosity at the surface and through the thickness of the fibrous scaffolds, as demonstrated by the results of this study, provides a powerful means of engineering the three-dimensional structure of electrospun fibrous scaffolds for cell and tissue engineering. PMID:23534553

  19. Effect of random/aligned nylon-6/MWCNT fibers on dental resin composite reinforcement.

    PubMed

    Borges, Alexandre L S; Münchow, Eliseu A; de Oliveira Souza, Ana Carolina; Yoshida, Takamitsu; Vallittu, Pekka K; Bottino, Marco C

    2015-08-01

    The aims of this study were (1) to synthesize and characterize random and aligned nanocomposite fibers of multi-walled carbon nanotubes (MWCNT)/nylon-6 and (2) to determine their reinforcing effects on the flexural strength of a dental resin composite. Nylon-6 was dissolved in hexafluoropropanol (10 wt%), followed by the addition of MWCNT (hereafter referred to as nanotubes) at two distinct concentrations (i.e., 0.5 or 1.5 wt%). Neat nylon-6 fibers (without nanotubes) were also prepared. The solutions were electrospun using parameters under low- (120 rpm) or high-speed (6000 rpm) mandrel rotation to collect random and aligned fibers, respectively. The processed fiber mats were characterized by scanning (SEM) and transmission (TEM) electron microscopies, as well as by uni-axial tensile testing. To determine the reinforcing effects on the flexural strength of a dental resin composite, bar-shaped (20×2×2 mm(3)) resin composite specimens were prepared by first placing one increment of the composite, followed by one strip of the mat, and one last increment of composite. Non-reinforced composite specimens were used as the control. The specimens were then evaluated using flexural strength testing. SEM was done on the fractured surfaces. The data were analyzed using ANOVA and the Tukey׳s test (α=5%). Nanotubes were successfully incorporated into the nylon-6 fibers. Aligned and random fibers were obtained using high- and low-speed electrospinning, respectively, where the former were significantly (p<0.001) stronger than the latter, regardless of the nanotubes׳ presence. Indeed, the dental resin composite tested was significantly reinforced when combined with nylon-6 fibrous mats composed of aligned fibers (with or without nanotubes) or random fibers incorporated with nanotubes at 0.5 wt%.

  20. Light-driven wettability changes on a photoresponsive electrospun mat.

    PubMed

    Chen, Menglin; Besenbacher, Flemming

    2011-02-22

    Novel nanofibers of biodegradable polycaprolactone (PCL) modified with light-responsive azobenzene were prepared by electrospinning upon a facile one-pot reaction. The surface chemistry of the nanofibers was probed by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Both XPS and ToF-SIMS spectra proved the successful conjugation of azobenzene with PCL. ToF-SIMS not only enabled chemical mapping but also provided morphology information, supplementary to scanning electron microscopy (SEM). The large, reversible, and light-responsive wettability changes of the functional fibrous surfaces were further demonstrated using UV-vis spectroscopy and contact angle (CA) measurements.

  1. Fabrication and characterization of vitamin B5 loaded poly (l-lactide-co-caprolactone)/silk fiber aligned electrospun nanofibers for schwann cell proliferation.

    PubMed

    Bhutto, M Aqeel; Wu, Tong; Sun, Binbin; Ei-Hamshary, Hany; Al-Deyab, Salem S; Mo, Xiumei

    2016-08-01

    Bioengineering strategies for peripheral nerve regeneration have been focusing on the development of alternative treatments for nerve repair. In present study we have blended the Vitamin B5 (50mg) with 8% P(LLA-CL) and P(LLA-CL)/SF solutions and produced aligned electrospun nanofiber mashes and characterized the material for its physiochemical and mechanical characteristics. The vitamin loaded composites nanofibers showed tensile strength of 8.73±1.38 and 8.4±1.37 in P(LLA-CL)/Vt and P(LLA-CL)/SF/Vt nanofibers mashes, respectively. By the addition of vitamin B5 the P(LLA-CL) nanofibers become hydrophilic and the contact angle decreased from 96° to 0° in 6min of duration. The effect of vitamin B5 on Schwann cells proliferation and viability were analyzed by using MTT assay and the number of cells cultured on vitamin loaded nanofiber mashes was significantly higher than the without vitamin loaded nanofiber samples after 5th day (p<0.05) whereas, P (LLA-CL)/SF/Vt exhibit the consistently highest cell numbers after 7th days culture as compare to P (LLA-CL)/Vt. The in vitro vitamin release behavior was observed in PBS solution and released vitamin was calculated by revers phase HPLC method. The sustain release behavior of vitamin B5 were noted higher in P(LLA-CL)/Vt (80%) nanofibers as compared to P (LLA-CL)/SF/Vt (62%) nanofibers after 24h. The present work provided a basis for further studies of this novel aligned nanofibrous material in nerve tissue repair or regeneration.

  2. Fabrication and characterization of vitamin B5 loaded poly (l-lactide-co-caprolactone)/silk fiber aligned electrospun nanofibers for schwann cell proliferation.

    PubMed

    Bhutto, M Aqeel; Wu, Tong; Sun, Binbin; Ei-Hamshary, Hany; Al-Deyab, Salem S; Mo, Xiumei

    2016-08-01

    Bioengineering strategies for peripheral nerve regeneration have been focusing on the development of alternative treatments for nerve repair. In present study we have blended the Vitamin B5 (50mg) with 8% P(LLA-CL) and P(LLA-CL)/SF solutions and produced aligned electrospun nanofiber mashes and characterized the material for its physiochemical and mechanical characteristics. The vitamin loaded composites nanofibers showed tensile strength of 8.73±1.38 and 8.4±1.37 in P(LLA-CL)/Vt and P(LLA-CL)/SF/Vt nanofibers mashes, respectively. By the addition of vitamin B5 the P(LLA-CL) nanofibers become hydrophilic and the contact angle decreased from 96° to 0° in 6min of duration. The effect of vitamin B5 on Schwann cells proliferation and viability were analyzed by using MTT assay and the number of cells cultured on vitamin loaded nanofiber mashes was significantly higher than the without vitamin loaded nanofiber samples after 5th day (p<0.05) whereas, P (LLA-CL)/SF/Vt exhibit the consistently highest cell numbers after 7th days culture as compare to P (LLA-CL)/Vt. The in vitro vitamin release behavior was observed in PBS solution and released vitamin was calculated by revers phase HPLC method. The sustain release behavior of vitamin B5 were noted higher in P(LLA-CL)/Vt (80%) nanofibers as compared to P (LLA-CL)/SF/Vt (62%) nanofibers after 24h. The present work provided a basis for further studies of this novel aligned nanofibrous material in nerve tissue repair or regeneration. PMID:27085042

  3. Fabrication of electrospun poly (methyl methacrylate) nanofiber membranes

    NASA Astrophysics Data System (ADS)

    Sethupathy, M.; Sethuraman, V.; Manisankar, P.

    2013-02-01

    Electrospun nanofiber of poly(methyl methacrylate) (PMMA) was fabricated with different concentrations of polymer solution and the optimum concentration arrived at was 15 wt %. The surface morphology of the electrospun membrane was observed by scanning electron microscopy. It consist of thin fibers with an average diameter of about 200-450 nm. The images revealed that the nanofibers showed uniform diameter and no bead formation was observed. Impedance measurements were done for the membranes. PMMA nanofiber membrane showed an ionic conductivity of 1.53 × 10-3 Scm-1 at room temperature. FTIR results confirmed that there was no chemical change in the polymer. The results suggested that electrolyte uptake, ionic conduction and thermal behavior were improved for the PMMA electrospun nanofiber. Hence these nanofibres can very well be employed for the construction of dye-sensitized solar cells and Lithium batteries.

  4. Fabrication and characterization of electrospun titania nanofibers

    SciTech Connect

    Chandrasekar, Ramya; Zhang, Lifeng; Howe, Jane Y; Hedin, Nyle E; Zhang, Y

    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.

  5. Revealing the Hierarchical Mechanical Strength of Single Cellulose Acetate Electrospun Filaments through Ultrasonic Breakage.

    PubMed

    Avó, João; Fernandes, Susete N; Godinho, Maria H

    2015-06-01

    The tensile strength of single cellulose acetate electrospun fibers is determined through sonication-induced fragmentation in water using a model previously developed by Terentjev and co-workers. The fragmentation of the electrospun fibers results in a gradual shortening of their length until a constant modal length is achieved. A single electrospun CA fiber tensile strength of ≈ 150 MPa (55-280 MPa) is determined based on fracture statistics. It is also observed that the fragmented fibers show bunches of nanofilaments at their ends with similar diameters to those of round structures observed in the cross-section of the initial electrospun fibers (≈ 38 nm). The sonication of these nanofilaments gives rise to spherical particles with similar diameter dimensions, which allows the estimation of a value of the tensile strength of the order of 2 MPa for these nanostructures. The aggregation and the alignment of the nano filaments inside the electrospun fiber should be the source of its higher strength value.

  6. Effect of electrospun nanofibers on flexural properties of fiberglass composites

    NASA Astrophysics Data System (ADS)

    White, Fatima T.

    In the present study, sintered electrospun TEOS nanofibers were interleaved in S2 fiberglass woven fabric layers, and composite panels were fabricated using the heated vacuum assisted resin transfer molding (H-VARTM) process. Cured panels were water jet cut to obtain the flexural test coupons. Flexural coupons were then tested using ASTM D7264 standard. The mechanical properties such as flexural strength, ultimate flexural failure strains, flexural modulus, and fiber volume fraction were measured. The S-2 fiberglass composite with the sintered TEOS electrospun nanofibers displayed lower flexural stiffness and strength as compared to the composites that were fabricated using S-2 fiberglass composite without the TEOS electrospun nanofibers. The present study also indicated that the composites fabricated with sintered TEOS electrospun nanofibers have larger failure strains as compared to the ones that were fabricated without the presence of electrospun nanofibers. The study indicates that the nanoengineered composites have better energy absorbing mechanism under flexural loading as compared to conventional fiberglass composites without presence of nanofibers.

  7. Biomimetic fiber assembled gradient hydrogel to engineer glycosaminoglycan enriched and mineralized cartilage: An in vitro study.

    PubMed

    Mohan, Neethu; Wilson, Jijo; Joseph, Dexy; Vaikkath, Dhanesh; Nair, Prabha D

    2015-12-01

    The study investigated the potential of electrospun fiber assembled hydrogel, with physical gradients of chondroitin sulfate (CS) and sol-gel-derived bioactive glass (BG), to engineer hyaline and mineralized cartilage in a single 3D system. Electrospun poly(caprolactone) (PCL) fibers incorporated with 0.1% w/w of CS (CSL) and 0.5% w/w of CS (CSH), 2.4% w/w of BG (BGL) and 12.5% w/w of BG (BGH) were fabricated. The CS showed a sustained release up to 3 days from CSL and 14 days from CSH fibers. Chondrocytes secreted hyaline like matrix with higher sulfated glycosaminoglycans (sGAG), collagen type II and aggrecan on CSL and CSH fibers. Mineralization was observed on BGL and BGH fibers when incubated in simulated body fluid for 14 days. Chondrocytes cultured on these fibers secreted a mineralized matrix that consisted of sGAG, hypertrophic proteins, collagen type X, and osteocalcin. The CS and BG incorporated PCL fiber mats were assembled in an agarose-gelatin hydrogel to generate a 3D hybrid scaffold. The signals in the fibers diffused and generated continuous opposing gradients of CS (chondrogenic signal) and BG (mineralization) in the hydrogel. The chondrocytes were encapsulated in hybrid scaffolds; live dead assay at 48 h showed viable cells. Cells maintained their phenotype and secreted specific extracellular matrix (ECM) in response to signals within the hydrogel. Continuous opposing gradients of sGAG enriched and mineralized ECM were observed surrounding each cell clusters on gradient hydrogel after 14 days of culture in response to the physical gradients of raw materials CS and BG. A construct with gradient mineralization might accelerate integration to subchondral bone during in vivo regeneration. PMID:26014103

  8. Biomimetic fiber assembled gradient hydrogel to engineer glycosaminoglycan enriched and mineralized cartilage: An in vitro study.

    PubMed

    Mohan, Neethu; Wilson, Jijo; Joseph, Dexy; Vaikkath, Dhanesh; Nair, Prabha D

    2015-12-01

    The study investigated the potential of electrospun fiber assembled hydrogel, with physical gradients of chondroitin sulfate (CS) and sol-gel-derived bioactive glass (BG), to engineer hyaline and mineralized cartilage in a single 3D system. Electrospun poly(caprolactone) (PCL) fibers incorporated with 0.1% w/w of CS (CSL) and 0.5% w/w of CS (CSH), 2.4% w/w of BG (BGL) and 12.5% w/w of BG (BGH) were fabricated. The CS showed a sustained release up to 3 days from CSL and 14 days from CSH fibers. Chondrocytes secreted hyaline like matrix with higher sulfated glycosaminoglycans (sGAG), collagen type II and aggrecan on CSL and CSH fibers. Mineralization was observed on BGL and BGH fibers when incubated in simulated body fluid for 14 days. Chondrocytes cultured on these fibers secreted a mineralized matrix that consisted of sGAG, hypertrophic proteins, collagen type X, and osteocalcin. The CS and BG incorporated PCL fiber mats were assembled in an agarose-gelatin hydrogel to generate a 3D hybrid scaffold. The signals in the fibers diffused and generated continuous opposing gradients of CS (chondrogenic signal) and BG (mineralization) in the hydrogel. The chondrocytes were encapsulated in hybrid scaffolds; live dead assay at 48 h showed viable cells. Cells maintained their phenotype and secreted specific extracellular matrix (ECM) in response to signals within the hydrogel. Continuous opposing gradients of sGAG enriched and mineralized ECM were observed surrounding each cell clusters on gradient hydrogel after 14 days of culture in response to the physical gradients of raw materials CS and BG. A construct with gradient mineralization might accelerate integration to subchondral bone during in vivo regeneration.

  9. Fiber

    MedlinePlus

    ... it can help with weight control. Fiber aids digestion and helps prevent constipation . It is sometimes used ... fiber attracts water and turns to gel during digestion. This slows digestion. Soluble fiber is found in ...

  10. Novel meloxicam releasing electrospun polymer/ceramic reinforced biodegradable membranes for periodontal regeneration applications.

    PubMed

    Yar, Muhammad; Farooq, Ariba; Shahzadi, Lubna; Khan, Abdul Samad; Mahmood, Nasir; Rauf, Abdul; Chaudhry, Aqif Anwar; Rehman, Ihtesham Ur

    2016-07-01

    Periodontal disease is associated with the destruction of periodontal tissues, along with other disorders/problems including inflammation of tissues and severe pain. This paper reports the synthesis of meloxicam (MX) immobilized biodegradable chitosan (CS)/poly(vinyl alcohol) (PVA)/hydroxyapatite (HA) based electrospun (e-spun) fibers and films. Electrospinning was employed to produce drug loaded fibrous mats, whereas films were generated by solvent casting method. In-vitro drug release from materials containing varying concentrations of MX revealed that the scaffolds containing higher amount of drug showed comparatively faster release. During initial first few hours fast release was noted from membranes and films; however after around 5h sustained release was achieved. The hydrogels showed good swelling property, which is highly desired for soft tissue engineered implants. To investigate the biocompatibility of our synthesized materials, VERO cells (epithelial cells) were selected and cell culture results showed that these all materials were non-cytotoxic and also these cells were very well proliferated on these synthesized scaffolds. These properties along with the anti-inflammatory potential of our fabricated materials suggest their effective utilization in periodontital treatments.

  11. Photocatalytic Oxidation of Volatile Organic Compounds Over Electrospun Activated TIO2/CARBON Nanofiber Composite

    NASA Astrophysics Data System (ADS)

    Gholamvand, Zahra; Aboutalebi, Seyed Hamed; Keyanpour-Rad, Mansoor

    In this study, TiO2/PAN-based fibers were prepared by electrospinning a composite solution containing both the desirable contents of TiO2 and a 10 wt. % PAN polymer solution dissolved in N, N-dimethylformamide. The TiO2 loaded electrospun PAN nanofibers were then carbonized at 1000 °C in N2 atmosphere furnace after stabilization at 230 °C in air. Then CNF/TiO2 nanofibers were oxidized at 450 °C in air. The morphology and structure of the TiO2-embeded carbon nanofibers were investigated by SEM and Raman spectroscopy. Specific surface area was determined using BET equation from N2 adsorption analysis. Photocatalytic tests were conducted in a UV illuminated set-up specialized for the filters using ethanol vapor. The results have shown that ethanol vapor was efficiently degraded on TiO2/CNF composite nanofiber mat under UV illumination. The aim of this study was to further investigate the feasibility of TiO2/ACF for practical indoor air purification.

  12. Novel meloxicam releasing electrospun polymer/ceramic reinforced biodegradable membranes for periodontal regeneration applications.

    PubMed

    Yar, Muhammad; Farooq, Ariba; Shahzadi, Lubna; Khan, Abdul Samad; Mahmood, Nasir; Rauf, Abdul; Chaudhry, Aqif Anwar; Rehman, Ihtesham Ur

    2016-07-01

    Periodontal disease is associated with the destruction of periodontal tissues, along with other disorders/problems including inflammation of tissues and severe pain. This paper reports the synthesis of meloxicam (MX) immobilized biodegradable chitosan (CS)/poly(vinyl alcohol) (PVA)/hydroxyapatite (HA) based electrospun (e-spun) fibers and films. Electrospinning was employed to produce drug loaded fibrous mats, whereas films were generated by solvent casting method. In-vitro drug release from materials containing varying concentrations of MX revealed that the scaffolds containing higher amount of drug showed comparatively faster release. During initial first few hours fast release was noted from membranes and films; however after around 5h sustained release was achieved. The hydrogels showed good swelling property, which is highly desired for soft tissue engineered implants. To investigate the biocompatibility of our synthesized materials, VERO cells (epithelial cells) were selected and cell culture results showed that these all materials were non-cytotoxic and also these cells were very well proliferated on these synthesized scaffolds. These properties along with the anti-inflammatory potential of our fabricated materials suggest their effective utilization in periodontital treatments. PMID:27127039

  13. Antimicrobial application of nanofibrous mats self-assembled with quaternized chitosan and soy protein isolate.

    PubMed

    Pan, Yijun; Huang, Xingjian; Shi, Xiaowen; Zhan, Yingfei; Fan, Gang; Pan, Siyi; Tian, Jing; Deng, Hongbing; Du, Yumin

    2015-11-20

    Positively charged N-[(2-hydroxy-3-trimethylammonium) propyl] chitosan chloride (HTCC) and negatively charged soy protein isolate (SPI) were alternately assembled on cellulose acetate (CA) electrospun nanofibrous mats via electrostatic layer-by-layer self-assembly technique. CA nanofibrous mats coated with bilayers of HTCC and SPI possessed more orderly-arranged structure than uncoated CA mats according to the observation from scanning electron microscopy images. The average diameter of the nanofibers was enlarged by the increase of the bilayer number. X-ray photoelectron spectroscopy indicated that HTCC and SPI were coated on the surface of the CA mats successfully. The average diameters of inhibition zones of (HTCC/SPI)10.5-films-coated nanofibrous mats against Escherichia coli and Staphylococcus aureus were 9.6mm and 11.53mm, respectively, which demonstrated the highest antimicrobial activity among samples in presented study. PMID:26344276

  14. Optimization of intrinsic and extrinsic tendon healing through controllable water-soluble mitomycin-C release from electrospun fibers by mediating adhesion-related gene expression.

    PubMed

    Zhao, Xin; Jiang, Shichao; Liu, Shen; Chen, Shuai; Lin, Zhi Yuan William; Pan, Guoqing; He, Fan; Li, Fengfeng; Fan, Cunyi; Cui, Wenguo

    2015-08-01

    To balance intrinsic and extrinsic healing during tendon repair is challenging in tendon surgery. We hypothesized that by mediating apoptotic gene and collagen synthesis of exogenous fibroblasts, the adhesion formation induced by extrinsic healing could be inhibited. With the maintenance of intrinsic healing, the tendon could be healed with proper function with no adhesion. In this study, we loaded hydrophilic mitomycin-C (MMC) into hyaluronan (HA) hydrosols, which were then encapsulated in poly(L-lactic acid) (PLLA) fibers by micro-sol electrospinning. This strategy successfully provided a controlled release of MMC to inhibit adhesion formations with no detrimental effect on intrinsic healing. We found that micro-sol electrospinning was an effective and facile approach to incorporate and control hydrophilic drug release from hydrophobic polyester fibers. MMC exhibited an initially rapid, and gradually steadier release during 40 days, and the release rates could be tuned by its concentration. In vitro studies revealed that low concentrations of MMC could inhibit fibroblast adhesion and proliferation. When lacerate tendons were healed using the MMC-HA loaded PLLA fibers in vivo, they exhibited comparable mechanical strength to the naturally healed tendons but with no significant presence of adhesion formation. We further identified the up-regulation of apoptotic protein Bax expression and down-regulation of proteins Bcl2, collage I, collagen III and α-SMA during the healing process associated with minimum adhesion formations. This approach presented here leverages new advances in drug delivery and nanotechnology and offers a promising strategy to balance intrinsic and extrinsic tendon healing through modulating genes associated with fibroblast apoptosis and collagen synthesis.

  15. Electrospun porous carbon nanofiber@MoS2 core/sheath fiber membranes as highly flexible and binder-free anodes for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    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

  16. Surface chemistry of electrospun cellulose nitrate nanofiber membranes.

    PubMed

    Nartker, Steven; Askeland, Per; Wiederoder, Sara; Drzal, Lawrence T

    2011-02-01

    Electrospinning is a rapidly developing technology that provides a unique way to produce novel polymer nanofibers with controllable diameters. Cellulose nitrate non-woven mats of submicron-sized fibers with diameters of 100-1200 nm were prepared. The effects of processing equipment collector design void gap, and steel drum coated with polyvinylidene dichloride (PVDC) were investigated. The PVDC layer applied to the rotating drum aided in fiber harvesting. Electron microscopy (FESEM and ESEM) studies of as-spun fibers revealed that the morphology of cellulose nitrate fibers depended on the collector type and solution viscosity. When a rotating steel drum was employed a random morphology was observed, while the void gap collector produced aligned fiber mats. Increases in viscosity lead to larger diameter fibers. The fibers collected were free from all residual solvents and could undergo oxygen plasma treatment to increase the hydropholicity. PMID:21456166

  17. TOPICAL REVIEW: Electrospun nanofibrous materials for tissue engineering and drug delivery

    NASA Astrophysics Data System (ADS)

    Cui, Wenguo; Zhou, Yue; Chang, Jiang

    2010-02-01

    The electrospinning technique, which was invented about 100 years ago, has attracted more attention in recent years due to its possible biomedical applications. Electrospun fibers with high surface area to volume ratio and structures mimicking extracellular matrix (ECM) have shown great potential in tissue engineering and drug delivery. In order to develop electrospun fibers for these applications, different biocompatible materials have been used to fabricate fibers with different structures and morphologies, such as single fibers with different composition and structures (blending and core-shell composite fibers) and fiber assemblies (fiber bundles, membranes and scaffolds). This review summarizes the electrospinning techniques which control the composition and structures of the nanofibrous materials. It also outlines possible applications of these fibrous materials in skin, blood vessels, nervous system and bone tissue engineering, as well as in drug delivery.

  18. Porous nitrogen doped carbon fiber with churros morphology derived from electrospun bicomponent polymer as highly efficient electrocatalyst for Zn-air batteries

    NASA Astrophysics Data System (ADS)

    Park, Gi Su; Lee, Jang-Soo; Kim, Sun Tai; Park, Soojin; Cho, Jaephil

    2013-12-01

    Highly porous nitrogen doped carbon fibers like churros morphology are prepared from a simple and cost-effective fabrication process, electrospinning with bicomponent polymer consisting of polystyrene (PS) and polyacrylonitrile (PAN). From appropriate ratio of two polymer and pyrolysis at 1100 °C, newly churros morphology with extremely high surface area (1271 m2 g-1) is prepared. During carbonization, more unstable PS than PAN plays a critical role in forming such morphology by acting as sacrifice materials, thus providing additional formation of inner pores and outer etched surfaces. Furthermore, it demonstrates excellent electrocatalytic activity toward ORR, which is attributed to highly meso- and macro porous nitrogen-doped large surface area and enhanced graphitic-nitrogen groups of carbon fibers. For example, the performance of a Zn-air cell based on the nitrogen-doped porous carbon nanofibers exhibits a peak power density of 194 mW cm-2, comparable to that based on a commercial Pt/C catalyst (192 mW cm-2). Further, the generation of hydrogen peroxide ions (<20%) in a half cell is similar to that on the commercial Pt/C catalyst.

  19. Immobilization of gold nanoclusters inside porous electrospun fibers for selective detection of Cu(II): A strategic approach to shielding pristine performance

    PubMed Central

    Senthamizhan, Anitha; Celebioglu, Asli; Balusamy, Brabu; Uyar, Tamer

    2015-01-01

    Here, a distinct demonstration of highly sensitive and selective detection of copper (Cu2+) in a vastly porous cellulose acetate fibers (pCAF) has been carried out using dithiothreitol capped gold nanocluster (DTT.AuNC) as fluorescent probe. A careful optimization of all potential factors affecting the performance of the probe for effective detection of Cu2+ were studied and the resultant sensor strip exhibiting unique features including high stability, retained parent fluorescence nature and reproducibility. The visual colorimetric detection of Cu2+ in water, presenting the selective sensing performance towards Cu2+ ions over Zn2+, Cd2+ and Hg2+ under UV light in naked eye, contrast to other metal ions that didn’t significantly produce such a change. The comparative sensing performance of DTT.AuNC@pCAF, keeping the nonporous CA fiber (DTT.AuNC@nCAF) as a support matrix has been demonstrated. The resulting weak response of DTT.AuNC@nCAF denotes the lack of ligand protection leading to the poor coordination ability with Cu2+. The determined detection limit (50 ppb) is far lower than the maximum level of Cu2+ in drinking water (1.3 ppm) set by U.S. Environmental Protection Agency (EPA). An interesting find from this study has been the specific oxidation nature between Cu2+ and DTT.AuNC, offering solid evidence for selective sensors. PMID:26489771

  20. Coaxial electrospun aligned tussah silk fibroin nanostructured fiber scaffolds embedded with hydroxyapatite-tussah silk fibroin nanoparticles for bone tissue engineering.

    PubMed

    Shao, Weili; He, Jianxin; Sang, Feng; Ding, Bin; Chen, Li; Cui, Shizhong; Li, Kejing; Han, Qiming; Tan, Weilin

    2016-01-01

    The bone is a composite of inorganic and organic materials and possesses a complex hierarchical architecture consisting of mineralized fibrils formed by collagen molecules and coated with oriented hydroxyapatite. To regenerate bone tissue, it is necessary to provide a scaffold that mimics the architecture of the extracellular matrix in native bone. Here, we describe one such scaffold, a nanostructured composite with a core made of a composite of hydroxyapatite and tussah silk fibroin. The core is encased in a shell of tussah silk fibroin. The composite fibers were fabricated by coaxial electrospinning using green water solvent and were characterized using different techniques. In comparison to nanofibers of pure tussah silk, composite notably improved mechanical properties, with 90-fold and 2-fold higher initial modulus and breaking stress, respectively, obtained. Osteoblast-like MG-63 cells were cultivated on the composite to assess its suitability as a scaffold for bone tissue engineering. We found that the fiber scaffold supported cell adhesion and proliferation and functionally promoted alkaline phosphatase and mineral deposition relevant for biomineralization. In addition, the composite were more biocompatible than pure tussah silk fibroin or cover slip. Thus, the nanostructured composite has excellent biomimetic and mechanical properties and is a potential biocompatible scaffold for bone tissue engineering. PMID:26478319

  1. Immobilization of gold nanoclusters inside porous electrospun fibers for selective detection of Cu(II): A strategic approach to shielding pristine performance.

    PubMed

    Senthamizhan, Anitha; Celebioglu, Asli; Balusamy, Brabu; Uyar, Tamer

    2015-10-22

    Here, a distinct demonstration of highly sensitive and selective detection of copper (Cu(2+)) in a vastly porous cellulose acetate fibers (pCAF) has been carried out using dithiothreitol capped gold nanocluster (DTT.AuNC) as fluorescent probe. A careful optimization of all potential factors affecting the performance of the probe for effective detection of Cu(2+) were studied and the resultant sensor strip exhibiting unique features including high stability, retained parent fluorescence nature and reproducibility. The visual colorimetric detection of Cu(2+) in water, presenting the selective sensing performance towards Cu(2+) ions over Zn(2+), Cd(2+) and Hg(2+) under UV light in naked eye, contrast to other metal ions that didn't significantly produce such a change. The comparative sensing performance of DTT.AuNC@pCAF, keeping the nonporous CA fiber (DTT.AuNC@nCAF) as a support matrix has been demonstrated. The resulting weak response of DTT.AuNC@nCAF denotes the lack of ligand protection leading to the poor coordination ability with Cu(2+). The determined detection limit (50 ppb) is far lower than the maximum level of Cu(2+) in drinking water (1.3 ppm) set by U.S. Environmental Protection Agency (EPA). An interesting find from this study has been the specific oxidation nature between Cu(2+) and DTT.AuNC, offering solid evidence for selective sensors.

  2. Immobilization of gold nanoclusters inside porous electrospun fibers for selective detection of Cu(II): A strategic approach to shielding pristine performance

    NASA Astrophysics Data System (ADS)

    Senthamizhan, Anitha; Celebioglu, Asli; Balusamy, Brabu; Uyar, Tamer

    2015-10-01

    Here, a distinct demonstration of highly sensitive and selective detection of copper (Cu2+) in a vastly porous cellulose acetate fibers (pCAF) has been carried out using dithiothreitol capped gold nanocluster (DTT.AuNC) as fluorescent probe. A careful optimization of all potential factors affecting the performance of the probe for effective detection of Cu2+ were studied and the resultant sensor strip exhibiting unique features including high stability, retained parent fluorescence nature and reproducibility. The visual colorimetric detection of Cu2+ in water, presenting the selective sensing performance towards Cu2+ ions over Zn2+, Cd2+ and Hg2+ under UV light in naked eye, contrast to other metal ions that didn’t significantly produce such a change. The comparative sensing performance of DTT.AuNC@pCAF, keeping the nonporous CA fiber (DTT.AuNC@nCAF) as a support matrix has been demonstrated. The resulting weak response of DTT.AuNC@nCAF denotes the lack of ligand protection leading to the poor coordination ability with Cu2+. The determined detection limit (50 ppb) is far lower than the maximum level of Cu2+ in drinking water (1.3 ppm) set by U.S. Environmental Protection Agency (EPA). An interesting find from this study has been the specific oxidation nature between Cu2+ and DTT.AuNC, offering solid evidence for selective sensors.

  3. Coaxial electrospun aligned tussah silk fibroin nanostructured fiber scaffolds embedded with hydroxyapatite-tussah silk fibroin nanoparticles for bone tissue engineering.

    PubMed

    Shao, Weili; He, Jianxin; Sang, Feng; Ding, Bin; Chen, Li; Cui, Shizhong; Li, Kejing; Han, Qiming; Tan, Weilin

    2016-01-01

    The bone is a composite of inorganic and organic materials and possesses a complex hierarchical architecture consisting of mineralized fibrils formed by collagen molecules and coated with oriented hydroxyapatite. To regenerate bone tissue, it is necessary to provide a scaffold that mimics the architecture of the extracellular matrix in native bone. Here, we describe one such scaffold, a nanostructured composite with a core made of a composite of hydroxyapatite and tussah silk fibroin. The core is encased in a shell of tussah silk fibroin. The composite fibers were fabricated by coaxial electrospinning using green water solvent and were characterized using different techniques. In comparison to nanofibers of pure tussah silk, composite notably improved mechanical properties, with 90-fold and 2-fold higher initial modulus and breaking stress, respectively, obtained. Osteoblast-like MG-63 cells were cultivated on the composite to assess its suitability as a scaffold for bone tissue engineering. We found that the fiber scaffold supported cell adhesion and proliferation and functionally promoted alkaline phosphatase and mineral deposition relevant for biomineralization. In addition, the composite were more biocompatible than pure tussah silk fibroin or cover slip. Thus, the nanostructured composite has excellent biomimetic and mechanical properties and is a potential biocompatible scaffold for bone tissue engineering.

  4. Electrospun nitrocellulose and nylon: Design and fabrication of novel high performance platforms for protein blotting applications

    PubMed Central

    Manis, Ashley E; Bowman, James R; Bowlin, Gary L; Simpson, David G

    2007-01-01

    Background Electrospinning is a non-mechanical processing strategy that can be used to process a variety of native and synthetic polymers into highly porous materials composed of nano-scale to micron-scale diameter fibers. By nature, electrospun materials exhibit an extensive surface area and highly interconnected pore spaces. In this study we adopted a biological engineering approach to ask how the specific unique advantages of the electrospinning process might be exploited to produce a new class of research/diagnostic tools. Methods The electrospinning properties of nitrocellulose, charged nylon and blends of these materials are characterized. Results Nitrocellulose electrospun from a starting concentration of < 110 mg/ml acetone deposited as 4–8 μm diameter beads; at 110 mg/ml-to-140 mg/ml starting concentrations, this polymer deposited as 100–4000 nm diameter fibers. Nylon formed fibers when electrospun from 60–140 mg/ml HFIP, fibers ranged from 120 nm-6000 nm in diameter. Electrospun nitrocellulose exhibited superior protein retention and increased sensitivity in slot blot experiments with respect to the parent nitrocellulose material. Western immunoblot experiments using fibronectin as a model protein demonstrated that electrospun nylon exhibits increased protein binding and increased dynamic range in the chemiluminescence detection of antigens than sheets of the parent starting material. Composites of electrospun nitrocellulose and electrospun nylon exhibit high protein binding activity and provide increased sensitivity for the immuno-detection of antigens. Conclusion The flexibility afforded by electrospinning process makes it possible to tailor blotting membranes to specific applications. Electrospinning has a variety of potential applications in the clinical diagnostic field of use. PMID:18271978

  5. Fumarate-loaded electrospun nanofibers with anti-inflammatory activity for fast recovery of mild skin burns.

    PubMed

    Romano, I; Summa, M; Heredia-Guerrero, J A; Spanò, R; Ceseracciu, L; Pignatelli, C; Bertorelli, R; Mele, E; Athanassiou, A

    2016-01-01

    In the biomedical sector the availability of engineered scaffolds and dressings that control and reduce inflammatory states is highly desired, particularly for the management of burn wounds. In this work, we demonstrate for the first time, to the best of our knowledge, that electrospun fibrous dressings of poly(octyl cyanoacrylate) (POCA) combined with polypropylene fumarate (PPF) possess anti-inflammatory activity and promote the fast and effective healing of mild skin burns in an animal model. The fibers produced had an average diameter of (0.8  ±  0.1) µm and they were able to provide a conformal coverage of the injured tissue. The application of the fibrous mats on the burned tissue effectively reduced around 80% of the levels of pro-inflammatory cytokines in the first 48 h in comparison with un-treated animals, and enhanced skin epithelialization. From histological analysis, the skin thickness of the animals treated with POCA : PPF dressings appeared similar to that of one of the naïve animals: (13.7  ±  1.4) µm and (14.3  ±  2.5) µm for naïve and treated animals, respectively. The density of dermal cells was comparable as well: (1100  ±  112) cells mm(-2) and (1358  ±  255) cells mm(-2) for naïve and treated mice, respectively. The results demonstrate the suitability of the electrospun dressings in accelerating and effectively promoting the burn healing process. PMID:27481333

  6. General Deposition of Metal-Organic Frameworks on Highly Adaptive Organic-Inorganic Hybrid Electrospun Fibrous Substrates.

    PubMed

    Liu, Chang; Wu, Yi-Nan; Morlay, Catherine; Gu, Yifan; Gebremariam, Binyam; Yuan, Xiao; Li, Fengting

    2016-02-01

    Electrospun nanofibrous mats are ideal substrates for metal-organic frameworks (MOFs) crystal deposition because of their specific structural parameters and chemical tenability. In this work, we utilized organic-inorganic hybrid electrospun fibrous mats as support material to study the deposition of various MOF particles. HKUST-1 and MIL-53(Al) were produced through solvothermal method, while ZIF-8 and MIL-88B(Fe) were prepared using microwave-induced heating method. The synthesis procedure for both methods were simple and effective because the hybrid nanofibrous mats showed considerable affinity to MOF particles and could be used without additional modifications. The obtained MOF composites exhibited effective incorporation between MOF particles and the porous substrates. MIL-53(Al) composite was applied as fibrous sorbent and showed enhanced adsorption capacity and removal rate, as well as easier operation, compared with thepowdered sample. Moreover, MIL-53(Al) composite was easier to be regenerated compared with powder form.

  7. Enhancement of conductivity by diameter control of polyimide-based electrospun carbon nanofibers.

    PubMed

    Xuyen, Nguyen Thi; Ra, Eun Ju; Geng, Hong-Zhang; Kim, Ki Kang; An, Kay Hyeok; Lee, Young Hee

    2007-10-01

    Oxydianiline-pyromellitic dianhydride poly(amic acid) (ODA-PMDA PAA) was polymerized with a catalyst support of triethyl amine for controlling molecular weight. This polymer was used for electrospinning in the preparation of PAA nanofibers, a precursor of carbon nanofibers. Here the amount of catalyst and concentration of PAA solution were optimized to produce polyimide-based carbon nanofibers approximately 80 nm in diameter. The effects of molecular weight of PAA, bias voltage, and spinning rate on the morphology of electrospun PAA and polyimide nanofibers have been evaluated. We showed that the conductivity of the carbon nanofiber mat decreased with increasing nanofiber diameter, where the conductivity of polyimide-based carbon nanofiber mat was much higher than those of other types of carbon nanofiber mat. The key ingredient to increase conductivity in a carbon nanofiber mat was found to be the number of cross junctions between nanofibers. PMID:17850139

  8. Mechanical properties and biocompatibility of co-axially electrospun polyvinyl alcohol/maghemite.

    PubMed

    Ngadiman, Nor Hasrul Akhmal; Mohd Yusof, Noordin; Idris, Ani; Kurniawan, Denni

    2016-08-01

    Electrospinning is a simple and efficient process in producing nanofibers. To fabricate nanofibers made of a blend of two constituent materials, co-axial electrospinning method is an option. In this method, the constituent materials contained in separate barrels are simultaneously injected using two syringe nozzles arranged co-axially and the materials mix during the spraying process forming core and shell of the nanofibers. In this study, co-axial electrospinning method is used to fabricate nanofibers made of polyvinyl alcohol and maghemite (γ-Fe2O3). The concentration of polyvinyl alcohol and amount of maghemite nanoparticle loading were varied, at 5 and 10 w/v% and at 1-10 v/v%, respectively. The mechanical properties (strength and Young's modulus), porosity, and biocompatibility properties (contact angle and cell viability) of the electrospun mats were evaluated, with the same mats fabricated by regular single-nozzle electrospinning method as the control. The co-axial electrospinning method is able to fabricate the expected polyvinyl alcohol/maghemite nanofiber mats. It was noticed that the polyvinyl alcohol/maghemite electrospun mats have lower mechanical properties (i.e. strength and stiffness) and porosity, more hydrophilicity (i.e. lower contact angle), and similar cell viability compared to the mats fabricated by single-nozzle electrospinning method. PMID:27194535

  9. Mechanical properties and biocompatibility of co-axially electrospun polyvinyl alcohol/maghemite.

    PubMed

    Ngadiman, Nor Hasrul Akhmal; Mohd Yusof, Noordin; Idris, Ani; Kurniawan, Denni

    2016-08-01

    Electrospinning is a simple and efficient process in producing nanofibers. To fabricate nanofibers made of a blend of two constituent materials, co-axial electrospinning method is an option. In this method, the constituent materials contained in separate barrels are simultaneously injected using two syringe nozzles arranged co-axially and the materials mix during the spraying process forming core and shell of the nanofibers. In this study, co-axial electrospinning method is used to fabricate nanofibers made of polyvinyl alcohol and maghemite (γ-Fe2O3). The concentration of polyvinyl alcohol and amount of maghemite nanoparticle loading were varied, at 5 and 10 w/v% and at 1-10 v/v%, respectively. The mechanical properties (strength and Young's modulus), porosity, and biocompatibility properties (contact angle and cell viability) of the electrospun mats were evaluated, with the same mats fabricated by regular single-nozzle electrospinning method as the control. The co-axial electrospinning method is able to fabricate the expected polyvinyl alcohol/maghemite nanofiber mats. It was noticed that the polyvinyl alcohol/maghemite electrospun mats have lower mechanical properties (i.e. strength and stiffness) and porosity, more hydrophilicity (i.e. lower contact angle), and similar cell viability compared to the mats fabricated by single-nozzle electrospinning method.

  10. Effect of surfactant types on the biocompatibility of electrospun HAp/PHBV composite nanofibers.

    PubMed

    Suslu, A; Albayrak, A Z; Urkmez, A S; Bayir, E; Cocen, U

    2014-12-01

    Bone tissue engineering literature conveys investigations regarding biodegradable polymers where bioactive inorganic materials are added either before or after electrospinning process. The goal is to mimic the composition of bone and enhance the biocompatibility of the materials. Yet, most polymeric materials are hydrophobic in nature; therefore, their surfaces are not favorable for human cellular adhesion. In this sense, modifications of the hydrophobic surface of electrospun polymer fibers with hydrophilic and bioactive nanoparticles are beneficial. In this work, dispersion of hydroxyapatite (HAp), which is similar to the mineral component of natural bone, within biodegradable and biocompatible polymer poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with the aid of a surfactant has been investigated. Non-ionic TWEEN20 and 12-hydroxysteric acid (HSA), cationic dodecyl trimethyl ammonium bromide (DTAB) and anionic sodium deoxycholate and sodium dodecyl sulfate (SDS) surfactants were used for comparison in order to prepare stable and homogenous nanocomposite suspensions of HAp/PHBV for the electrospinning process. Continuous and uniform composite nanofibers were generated successfully within a diameter range of 400-1,000 nm by the mediation of all surfactant types. Results showed that incorporation of HAp and any of the surfactant types strongly activates the precipitation rate of the apatite-like particles and decreases percent crystallinity of the HAp/PHBV mats. Mineralization was greatly enhanced on the fibers produced by using DTAB, HSA, and especially SDS on where also osteoblastic metabolic activity was similarly increased. The produced HAp/PHBV nanofibrous composite scaffolds would be a promising candidate as an osteoconductive bioceramic/polymer composite material for tissue engineering applications.

  11. Electrospun fibre diameter, not alignment, affects mesenchymal stem cell differentiation into the tendon/ligament lineage.

    PubMed

    Cardwell, Robyn D; Dahlgren, Linda A; Goldstein, Aaron S

    2014-12-01

    Efforts to develop engineered tendons and ligaments have focused on the use of a biomaterial scaffold and a stem cell source. However, the ideal scaffold microenvironment to promote stem cell differentiation and development of organized extracellular matrix is unknown. Through electrospinning, fibre scaffolds can be designed with tailorable architectures to mimic the intended tissue. In this study, the effects of fibre diameter and orientation were examined by electrospinning thin mats, consisting of small (< 1 µm), medium (1-2 µm) or large (> 2 µm) diameter fibres with either random or aligned fibre orientation. C3H10T1/2 model stem cells were cultured on the six different electrospun mats, as well as smooth spin-coated films, and the morphology, growth and expression of tendon/ligament genes were evaluated. The results demonstrated that fibre diameter affects cellular behaviour more significantly than fibre alignment. Initially, cell density was greater on the small fibre diameter mats, but similar cell densities were found on all mats after an additional week in culture. After 2 weeks, gene expression of collagen 1α1 and decorin was increased on all mats compared to films. Expression of the tendon/ligament transcription factor scleraxis was suppressed on all electrospun mats relative to spin-coated films, but expression on the large-diameter fibre mats was consistently greater than on the medium-diameter fibre mats. These results suggest that larger-diameter fibres (e.g. > 2 µm) may be more suitable for in vitro development of a tendon/ligament tissue.

  12. Novel silicificated PVAc/POSS composite nanofibrous mat via facile electrospinning technique: potential scaffold for hard tissue engineering.

    PubMed

    Ha, Yu-Mi; Amna, Touseef; Kim, Mi-Hee; Kim, Hyun-Chel; Hassan, M Shamshi; Khil, Myung-Seob

    2013-02-01

    This study presents the fabrication of novel porous silicificated PVAc/POSS composite nanofibers by facile electrospinning technique and the interaction of synthesized mats with simulated body fluid (SBF). The physicochemical properties of the electrospun composites were determined by scanning electron microscopy, energy dispersive X-ray spectroscopy, transmission electron microscopy, electron probe micro-analysis, X-ray diffraction and thermogravimetry analysis. To examine the in vitro cytotoxicity, mouse myoblast C2C12 cells were treated with pristine and composite nanofibrous mats and the viability of cells was analyzed by cell counting kit-8 assay at regular time intervals. Our results indicated the enhanced nucleation and the formation of apatite-like structures at the surface of silicificated PVAc/POSS during the incubation of electrospun mats in SBF solution. Cytotoxicity experiments designated that the myoblasts could attach to the composite after being cultured. We observed in the present study that PVAc/POSS nanofibrous mat could support cell adhesion and guide the spreading behavior of myoblasts. We conclude that the new electrospun silicificated PVAc/POSS composite scaffold with unique porous morphology have excellent biocompatibility. Consequently, our investigation results showed that the as-spun porous PVAc/POSS composite nanofibrous scaffold could be a potential substrate for the proliferation and mineralization of osteoblasts, enhancing bone regeneration. The biocomposite mats represent a promising biomaterial to be exploited for various tissue engineering applications such as guided bone regeneration. PMID:23107958

  13. ProMat

    SciTech Connect

    2008-06-12

    ProMAT is a software tool for statistically analyzing data from enzyme-linked immunosorbent assay microarray experiments. The software estimates standard curves, sample protein concentrations and their uncertainties for multiple assays. ProMAT generates a set of comprehensive figures for assessing results and diagnosing process quality. The tool is available for Windows or Mac, and is distributed as open-source Java and R code

  14. Effect of clay content on morphology and processability of electrospun keratin/poly(lactic acid) nanofiber.

    PubMed

    Isarankura Na Ayutthaya, Siriorn; Tanpichai, Supachok; Sangkhun, Weradesh; Wootthikanokkhan, Jatuphorn

    2016-04-01

    This research work has concerned the development of volatile organic compounds (VOCs) removal filters from biomaterials, based on keratin extracted from chicken feather waste and poly(lactic acid) (PLA) (50/50%w/w) blend. Clay (Na-montmorillonite) was also added to the blend solution prior to carrying out an electro-spinning process. The aim of this study was to investigate the effect of clay content on viscosity, conductivity, and morphology of the electrospun fibers. Scanning electron micrographs showed that smooth and bead-free fibers were obtained when clay content used was below 2 pph. XRD patterns of the electrospun fibers indicated that the clay was intercalated and exfoliated within the polymers matrix. Percentage crystallinity of keratin in the blend increased after adding the clay, as evidenced from FTIR spectra and DSC thermograms. Transmission electron micrographs revealed a kind of core-shell structure with clay being predominately resided within the keratin rich shell and at the interfacial region. Filtration performance of the electrospun keratin/PLA fibers, described in terms of pressure drop and its capability of removing methylene blue, were also explored. Overall, our results demonstrated that it was possible to improve process-ability, morphology and filtration efficiency of the electrospun keratin fibers by adding a suitable amount of clay.

  15. Effect of clay content on morphology and processability of electrospun keratin/poly(lactic acid) nanofiber.

    PubMed

    Isarankura Na Ayutthaya, Siriorn; Tanpichai, Supachok; Sangkhun, Weradesh; Wootthikanokkhan, Jatuphorn

    2016-04-01

    This research work has concerned the development of volatile organic compounds (VOCs) removal filters from biomaterials, based on keratin extracted from chicken feather waste and poly(lactic acid) (PLA) (50/50%w/w) blend. Clay (Na-montmorillonite) was also added to the blend solution prior to carrying out an electro-spinning process. The aim of this study was to investigate the effect of clay content on viscosity, conductivity, and morphology of the electrospun fibers. Scanning electron micrographs showed that smooth and bead-free fibers were obtained when clay content used was below 2 pph. XRD patterns of the electrospun fibers indicated that the clay was intercalated and exfoliated within the polymers matrix. Percentage crystallinity of keratin in the blend increased after adding the clay, as evidenced from FTIR spectra and DSC thermograms. Transmission electron micrographs revealed a kind of core-shell structure with clay being predominately resided within the keratin rich shell and at the interfacial region. Filtration performance of the electrospun keratin/PLA fibers, described in terms of pressure drop and its capability of removing methylene blue, were also explored. Overall, our results demonstrated that it was possible to improve process-ability, morphology and filtration efficiency of the electrospun keratin fibers by adding a suitable amount of clay. PMID:26776870

  16. Electrospinning strategies of drug-incorporated nanofibrous mats for wound recovery.

    PubMed

    Choi, Ji Suk; Kim, Hye Sung; Yoo, Hyuk Sang

    2015-04-01

    Electrospun nanofibrous mats have recently been employed as drug reservoirs for their unique features, such as high surface-to-volume ratios and easy fabrication process. We describe herein various methods of fabricating drug- and gene-encapsulated nanofibrous meshes, which can be prepared by electrospinning. The electrospinning process of nanofibrous mats is affected by many parameters, including viscosity and ejection speeds of the polymeric solutions and the electrical potential applied to the system. Both single- and dual-nozzle systems are widely employed in the preparation of electrospun nanofibers encapsulating drugs and genes, which are usually incorporated into the electrospun mats either by physical mixing with polymeric solutions before electrospinning or by physical incorporation after electrospinning. Various strategies have been tailored to maintain the bioactivity of proteins for tissue regeneration before and after electrospinning. Nucleic acids, such as DNA and siRNA, are also incorporated into nanofibrous meshes to enhance tissue regeneration by expressing transgenes or silencing domestic genes in specific tissues. Drug- or gene-incorporated nanofibrous meshes can greatly increase tissue regeneration rates and reduce scar formation in normal and diabetic wounds. Hybrid nanofibers, with multiple cell layers or hydrogels, have also been used to improve wound healing efficiency by increasing cell infiltration.

  17. Nanoclay-Enriched Poly(ɛ-caprolactone) Electrospun Scaffolds for Osteogenic Differentiation of Human Mesenchymal Stem Cells

    PubMed Central

    Gaharwar, Akhilesh K.; Mukundan, Shilpaa; Karaca, Elif; Dolatshahi-Pirouz, Alireza; Patel, Alpesh; Rangarajan, Kaushik; Mihaila, Silvia M.; Iviglia, Giorgio; Zhang, Hongbin

    2014-01-01

    Musculoskeletal tissue engineering aims at repairing and regenerating damaged tissues using biological tissue substitutes. One approach to achieve this aim is to develop osteoconductive scaffolds that facilitate the formation of functional bone tissue. We have fabricated nanoclay-enriched electrospun poly(ɛ-caprolactone) (PCL) scaffolds for osteogenic differentiation of human mesenchymal stem cells (hMSCs). A range of electrospun scaffolds is fabricated by varying the nanoclay concentrations within the PCL scaffolds. The addition of nanoclay decreases fiber diameter and increases surface roughness of electrospun fibers. The enrichment of PCL scaffold with nanoclay promotes in vitro biomineralization when subjected to simulated body fluid (SBF), indicating bioactive characteristics of the hybrid scaffolds. The degradation rate of PCL increases due to the addition of nanoclay. In addition, a significant increase in crystallization temperature of PCL is also observed due to enhanced surface interactions between PCL and nanoclay. The effect of nanoclay on the mechanical properties of electrospun fibers is also evaluated. The feasibility of using nanoclay-enriched PCL scaffolds for tissue engineering applications is investigated in vitro using hMSCs. The nanoclay-enriched electrospun PCL scaffolds support hMSCs adhesion and proliferation. The addition of nanoclay significantly enhances osteogenic differentiation of hMSCs on the electrospun scaffolds as evident by an increase in alkaline phosphates activity of hMSCs and higher deposition of mineralized extracellular matrix compared to PCL scaffolds. Given its unique bioactive characteristics, nanoclay-enriched PCL fibrous scaffold may be used for musculoskeletal tissue engineering. PMID:24842693

  18. Nanoclay-enriched poly(ɛ-caprolactone) electrospun scaffolds for osteogenic differentiation of human mesenchymal stem cells.

    PubMed

    Gaharwar, Akhilesh K; Mukundan, Shilpaa; Karaca, Elif; Dolatshahi-Pirouz, Alireza; Patel, Alpesh; Rangarajan, Kaushik; Mihaila, Silvia M; Iviglia, Giorgio; Zhang, Hongbin; Khademhosseini, Ali

    2014-08-01

    Musculoskeletal tissue engineering aims at repairing and regenerating damaged tissues using biological tissue substitutes. One approach to achieve this aim is to develop osteoconductive scaffolds that facilitate the formation of functional bone tissue. We have fabricated nanoclay-enriched electrospun poly(ɛ-caprolactone) (PCL) scaffolds for osteogenic differentiation of human mesenchymal stem cells (hMSCs). A range of electrospun scaffolds is fabricated by varying the nanoclay concentrations within the PCL scaffolds. The addition of nanoclay decreases fiber diameter and increases surface roughness of electrospun fibers. The enrichment of PCL scaffold with nanoclay promotes in vitro biomineralization when subjected to simulated body fluid (SBF), indicating bioactive characteristics of the hybrid scaffolds. The degradation rate of PCL increases due to the addition of nanoclay. In addition, a significant increase in crystallization temperature of PCL is also observed due to enhanced surface interactions between PCL and nanoclay. The effect of nanoclay on the mechanical properties of electrospun fibers is also evaluated. The feasibility of using nanoclay-enriched PCL scaffolds for tissue engineering applications is investigated in vitro using hMSCs. The nanoclay-enriched electrospun PCL scaffolds support hMSCs adhesion and proliferation. The addition of nanoclay significantly enhances osteogenic differentiation of hMSCs on the electrospun scaffolds as evident by an increase in alkaline phosphates activity of hMSCs and higher deposition of mineralized extracellular matrix compared to PCL scaffolds. Given its unique bioactive characteristics, nanoclay-enriched PCL fibrous scaffold may be used for musculoskeletal tissue engineering. PMID:24842693

  19. Thermal conductivity of electrospun polyethylene nanofibers

    NASA Astrophysics Data System (ADS)

    Ma, Jian; Zhang, Qian; Mayo, Anthony; Ni, Zhonghua; Yi, Hong; Chen, Yunfei; Mu, Richard; Bellan, Leon M.; Li, Deyu

    2015-10-01

    We report on the structure-thermal transport property relation of individual polyethylene nanofibers fabricated by electrospinning with different deposition parameters. Measurement results show that the nanofiber thermal conductivity depends on the electric field used in the electrospinning process, with a general trend of higher thermal conductivity for fibers prepared with stronger electric field. Nanofibers produced at a 45 kV electrospinning voltage and a 150 mm needle-collector distance could have a thermal conductivity of up to 9.3 W m-1 K-1, over 20 times higher than the typical bulk value. Micro-Raman characterization suggests that the enhanced thermal conductivity is due to the highly oriented polymer chains and enhanced crystallinity in the electrospun nanofibers.

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

    NASA Astrophysics Data System (ADS)

    Susanto, H.; Samsudin, A. M.; Faz, M. W.; Rani, M. P. H.

    2016-04-01

    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.

  1. Electrochemical properties of electrospun poly(5-cyanoindole) submicron-fibrous electrode for zinc/polymer secondary battery

    NASA Astrophysics Data System (ADS)

    Cai, Zhijiang; Guo, Jie; Yang, Haizheng; Xu, Yi

    2015-04-01

    This study aims to develop an aqueous zinc/electrospun poly(5-cyanoindole) fibers secondary battery system. Zn foil and ZnCl2 are used as anode active materials and the electrolytic solution, respectively. Poly(5-cyanoindole) synthesized by chemical oxidation is electrospun into fibers and used as cathode active materials. FTIR and NMR test are carried out to investigate the chemical structure of poly(5-cyanoindole). Surface properties of electrospun poly(5-cyanoindole) fibers are studied by SEM, TEM, and BET. The performance of zinc/electrospun poly(5-cyanoindole) fibers battery system is evaluated in term of electrical conductivity, cyclic voltammogram, electrochemical impedance spectroscopy, discharge capacity and durability test. The cell achieves 2.0 V electromotive force with about 107-61 Ah Kg-1 discharge capacity at 0.2C-10C rate. At 800th cycle, the discharge capacity remains 80-57 Ah Kg-1 at 0.2C-2C rate, which is about 75-63% of the maximum discharge capacity. These results indicate that the cell has very excellent cyclic properties as well as fast charge/discharge properties. Electrospun poly(5-cyanoindole) fibers have been proved to be a better candidate than polyindole powder as cathode material in zinc/polymer battery.

  2. Electrospun materials for affinity-based engineering and drug delivery

    NASA Astrophysics Data System (ADS)

    Sill, T. J.; von Recum, H. A.

    2015-10-01

    Electrospinning is a process which can quickly and cheaply create materials of high surface to volume and aspect ratios from many materials, however in application toward drug delivery this can be a strong disadvantage as well. Diffusion of drug is proportional to the thickness of that device. In moving from macro to micro to nano-sized electrospun materials drug release rates change to profiles that are too fast to be therapeutically beneficial. In this work we use molecular interactions to further control the rate of release beyond that capable of diffusion alone. To do this we create materials with molecular pockets, which can "hold" therapeutic drugs through a reversible interaction such as a host/guest complexation. Through these complexes we show we are able to impact delivery of drug from electrospun materials, and also apply them in tissue engineering for the reversible presentation of biomolecules on a fiber surface.

  3. Cell Infiltration and Growth in a Low Density, Uncompressed Three-Dimensional Electrospun Nanofibrous Scaffold

    PubMed Central

    Blakeney, Bryan A.; Tambralli, Ajay; Anderson, Joel M.; Andukuri, Adinarayana; Lim, Dong-Jin; Dean, Derrick R.; Jun, Ho-Wook

    2010-01-01

    A limiting factor of traditional electrospinning is that the electrospun scaffolds consist entirely of tightly packed nanofiber layers that only provide a superficial porous structure due to the sheet-like assembly process. This unavoidable characteristic hinders cell infiltration and growth throughout the nanofibrous scaffolds. Numerous strategies have been tried to overcome this challenge, including the incorporation of nanoparticles, using larger microfibers, or removing embedded salt or water-soluble fibers to increase porosity. However, these methods still produce sheet-like nanofibrous scaffolds, failing to create a porous three-dimensional scaffold with good structural integrity. Thus, we have developed a three-dimensional cotton ball-like electrospun scaffold that consists of an accumulation of nanofibers in a low density and uncompressed manner. Instead of a traditional flat-plate collector, a grounded spherical dish and an array of needle-like probes were used to create a Focused, Low density, Uncompressed nanoFiber (FLUF) mesh scaffold. Scanning electron microscopy showed that the cotton ball-like scaffold consisted of electrospun nanofibers with a similar diameter but larger pores and less dense structure compared to the traditional electrospun scaffolds. In addition, laser confocal microscopy demonstrated an open porosity and loosely packed structure throughout the depth of the cotton ball-like scaffold, contrasting the superficially porous and tightly packed structure of the traditional electrospun scaffold. Cells seeded on the cotton ball-like scaffold infiltrated into the scaffold after 7 days of growth, compared to no penetrating growth for the traditional electrospun scaffold. Quantitative analysis showed approximately a 40% higher growth rate for cells on the cotton ball-like scaffold over a 7 day period, possibly due to the increased space for in-growth within the three-dimensional scaffolds. Overall, this method assembles a nanofibrous scaffold

  4. Polyhydroxyalkanoates: waste glycerol upgrade into electrospun fibrous scaffolds for stem cells culture.

    PubMed

    Canadas, Raphaël F; Cavalheiro, João M B T; Guerreiro, João D T; de Almeida, M Catarina M D; Pollet, Eric; da Silva, Cláudia Lobato; da Fonseca, M M R; Ferreira, Frederico Castelo

    2014-11-01

    This integrated study shows that waste glycerol can be bio-valorized by the fabrication of electrospun scaffolds for stem cells. Human mesenchymal stem cells (hMSC) provide an interesting model of regenerating cells because of their ability to differentiate into osteo-, chrondro-, adipo- and myogenic lineages. Moreover, hMSC have modulatory properties with potential on treatment of immunologic diseases. Electrospun fiber meshes offer tunable mechanical and physical properties that can mimic the structure of the native extracellular matrix, the natural environment where cells inhabit. Following a biorefinery approach, crude glycerol directly recovered from a biodiesel post-reaction stream was fed as major C source to Cupriavidus necator DSM 545 to produce polyhydroxyalkanoates at polymer titers of 9-25g/L. Two of the P(3HB-4HB-3HV) terpolymers produced, one containing 11.4% 4HB and 3.5% 3HV and the other containing 35.6% 4HB and 3.4% 3HV, were electrospun into fibers of average diameters of 600 and 1400nm, respectively. hMSC were cultured for 7 days in both fiber meshes, showing their ability to support stem cell growth at acceptable proliferation levels. Comparative results clearly demonstrate that scaffold topology is critical, with electrospun PHA fibers succeeding on the support of significant cell adhesion and proliferation, where planar PHA films failed.

  5. Co3O4 nanoparticles decorated carbon nanofiber mat as binder-free air-cathode for high performance rechargeable zinc-air batteries.

    PubMed

    Li, Bing; Ge, Xiaoming; Goh, F W Thomas; Hor, T S Andy; Geng, Dongsheng; Du, Guojun; Liu, Zhaolin; Zhang, Jie; Liu, Xiaogang; Zong, Yun

    2015-02-01

    An efficient, durable and low cost air-cathode is essential for a high performance metal-air battery for practical applications. Herein, we report a composite bifunctional catalyst, Co3O4 nanoparticles-decorated carbon nanofibers (CNFs), working as an efficient air-cathode in high performance rechargeable Zn-air batteries (ZnABs). The particles-on-fibers nanohybrid materials were derived from electrospun metal-ion containing polymer fibers followed by thermal carbonization and a post annealing process in air at a moderate temperature. Electrochemical studies suggest that the nanohybrid material effectively catalyzes oxygen reduction reaction via an ideal 4-electron transfer process and outperforms Pt/C in catalyzing oxygen evolution reactions. Accordingly, the prototype ZnABs exhibit a low discharge-charge voltage gap (e.g. 0.7 V, discharge-charge at 2 mA cm(-2)) with higher stability and longer cycle life compared to their counterparts constructed using Pt/C in air-cathode. Importantly, the hybrid nanofiber mat readily serves as an integrated air-cathode without the need of any further modification. Benefitting from its efficient catalytic activities and structural advantages, particularly the 3D architecture of highly conductive CNFs and the high loading density of strongly attached Co3O4 NPs on their surfaces, the resultant ZnABs show significantly improved performance with respect to the rate capability, cycling stability and current density, promising good potential in practical applications.

  6. Co3O4 nanoparticles decorated carbon nanofiber mat as binder-free air-cathode for high performance rechargeable zinc-air batteries.

    PubMed

    Li, Bing; Ge, Xiaoming; Goh, F W Thomas; Hor, T S Andy; Geng, Dongsheng; Du, Guojun; Liu, Zhaolin; Zhang, Jie; Liu, Xiaogang; Zong, Yun

    2015-02-01

    An efficient, durable and low cost air-cathode is essential for a high performance metal-air battery for practical applications. Herein, we report a composite bifunctional catalyst, Co3O4 nanoparticles-decorated carbon nanofibers (CNFs), working as an efficient air-cathode in high performance rechargeable Zn-air batteries (ZnABs). The particles-on-fibers nanohybrid materials were derived from electrospun metal-ion containing polymer fibers followed by thermal carbonization and a post annealing process in air at a moderate temperature. Electrochemical studies suggest that the nanohybrid material effectively catalyzes oxygen reduction reaction via an ideal 4-electron transfer process and outperforms Pt/C in catalyzing oxygen evolution reactions. Accordingly, the prototype ZnABs exhibit a low discharge-charge voltage gap (e.g. 0.7 V, discharge-charge at 2 mA cm(-2)) with higher stability and longer cycle life compared to their counterparts constructed using Pt/C in air-cathode. Importantly, the hybrid nanofiber mat readily serves as an integrated air-cathode without the need of any further modification. Benefitting from its efficient catalytic activities and structural advantages, particularly the 3D architecture of highly conductive CNFs and the high loading density of strongly attached Co3O4 NPs on their surfaces, the resultant ZnABs show significantly improved performance with respect to the rate capability, cycling stability and current density, promising good potential in practical applications. PMID:25522330

  7. Biogeochemistry of Microbial Mats

    NASA Technical Reports Server (NTRS)

    DesMarais, David J.; DeVincenizi, D. (Technical Monitor)

    2002-01-01

    The hierarchical organization of microbial ecosystems determines the rates of processes that shape Earth's environment, define the stage upon which major evolutionary events occurred, and create biosignatures in sediments and atmospheres. In cyanobacterial mats, oxygenic photosynthesis provides energy, organic substrates and oxygen to the ecosystem. Incident light changes with depth in the mat, both in intensity and spectral composition, and counteracting gradients of oxygen and sulfide shape the chemical microenvironment. A combination of benefits and hazards of light, oxygen and sulfide promotes the allocation of the various essential mat processes between light and dark periods and to various depths in the mat. Microliters produce hydrogen, small organic acids, nitrogen and sulfur species. Such compounds fuel a flow of energy and electrons in these ecosystems and thus shape interactions between groups of microorganisms. Coordinated observations of population distribution, abundance, and activity for an entire community are making fundamental questions in ecology accessible. These questions address those factors that sustain the remarkable diversity of microorganisms that are now being revealed by molecular techniques. These questions also target the processes that shape the various kinds of biosignatures that we will seek, both in ancient rocks from Earth and Mars, and in atmospheres of distant planets beyond our Solar System.

  8. Fiber

    MedlinePlus

    ... broccoli, spinach, and artichokes legumes (split peas, soy, lentils, etc.) almonds Look for the fiber content of ... salsa, taco sauce, and cheese for dinner. Add lentils or whole-grain barley to your favorite soups. ...

  9. Co3O4 nanoparticles decorated carbon nanofiber mat as binder-free air-cathode for high performance rechargeable zinc-air batteries

    NASA Astrophysics Data System (ADS)

    Li, Bing; Ge, Xiaoming; Goh, F. W. Thomas; Hor, T. S. Andy; Geng, Dongsheng; Du, Guojun; Liu, Zhaolin; Zhang, Jie; Liu, Xiaogang; Zong, Yun

    2015-01-01

    An efficient, durable and low cost air-cathode is essential for a high performance metal-air battery for practical applications. Herein, we report a composite bifunctional catalyst, Co3O4 nanoparticles-decorated carbon nanofibers (CNFs), working as an efficient air-cathode in high performance rechargeable Zn-air batteries (ZnABs). The particles-on-fibers nanohybrid materials were derived from electrospun metal-ion containing polymer fibers followed by thermal carbonization and a post annealing process in air at a moderate temperature. Electrochemical studies suggest that the nanohybrid material effectively catalyzes oxygen reduction reaction via an ideal 4-electron transfer process and outperforms Pt/C in catalyzing oxygen evolution reactions. Accordingly, the prototype ZnABs exhibit a low discharge-charge voltage gap (e.g. 0.7 V, discharge-charge at 2 mA cm-2) with higher stability and longer cycle life compared to their counterparts constructed using Pt/C in air-cathode. Importantly, the hybrid nanofiber mat readily serves as an integrated air-cathode without the need of any further modification. Benefitting from its efficient catalytic activities and structural advantages, particularly the 3D architecture of highly conductive CNFs and the high loading density of strongly attached Co3O4 NPs on their surfaces, the resultant ZnABs show significantly improved performance with respect to the rate capability, cycling stability and current density, promising good potential in practical applications.An efficient, durable and low cost air-cathode is essential for a high performance metal-air battery for practical applications. Herein, we report a composite bifunctional catalyst, Co3O4 nanoparticles-decorated carbon nanofibers (CNFs), working as an efficient air-cathode in high performance rechargeable Zn-air batteries (ZnABs). The particles-on-fibers nanohybrid materials were derived from electrospun metal-ion containing polymer fibers followed by thermal carbonization

  10. Investigation of VEGGIE Root Mat

    NASA Technical Reports Server (NTRS)

    Subbiah, Arun M.

    2013-01-01

    VEGGIE is a plant growth facility that utilizes the phenomenon of capillary action as its primary watering system. A cloth made of Meta Aramid fiber, known as Nomex is used to wick water up from a reservoir to the bottom of the plants roots. This root mat system is intended to be low maintenance with no moving parts and requires minimal crew interface time. Unfortunately, the water wicking rates are inconsistent throughout the plant life cycle, thus causing plants to die. Over-wicking of water occurs toward the beginning of the cycle, while under-wicking occurs toward the middle. This inconsistency of wicking has become a major issue, drastically inhibiting plant growth. The primary objective is to determine the root cause of the inconsistent wicking through experimental testing. Suspect causes for the capillary water column to break include: a vacuum effect due to a negative pressure gradient in the water reservoir, contamination of material due to minerals in water and back wash from plant fertilizer, induced air bubbles while using syringe refill method, and material limitations of Nomex's ability to absorb and retain water. Experimental testing will be conducted to systematically determine the cause of under and over-wicking. Pressure gages will be used to determine pressure drop during the course of the plant life cycle and during the water refill process. A debubbler device will be connected to a root mat in order to equalize pressure inside the reservoir. Moisture and evaporation tests will simultaneously be implemented to observe moisture content and wicking rates over the course of a plant cycle. Water retention tests will be performed using strips of Nomex to determine materials wicking rates, porosity, and absorptivity. Through these experimental tests, we will have a better understanding of material properties of Nomex, as well as determine the root cause of water column breakage. With consistent test results, a forward plan can be achieved to resolve

  11. Electrospun Nanofibers for Regenerative Medicine**

    PubMed Central

    Liu, Wenying; Thomopoulos, Stavros

    2013-01-01

    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 techniques for controlling the alignment of nanofibers and for producing scaffolds with complex architectures. We also highlight applications of the nanofiber-based scaffolds in four areas of regenerative medicine that involve nerves, dural tissues, tendons, and the tendon-to-bone insertion site. We conclude this review with perspectives on challenges and future directions for design, fabrication, and utilization of scaffolds based on electrospun nanofibers. PMID:23184683

  12. Electrospun Poly(lactic acid-co-glycolic acid) Scaffolds for Skin Tissue Engineering

    PubMed Central

    Kumbar, Sangamesh G.; Nukavarapu, Syam Prasad; James, Roshan; Nair, Lakshmi S.; Laurencin, Cato T.

    2008-01-01

    Electrospun fiber matrices composed of scaffolds of varying fiber diameters were investigated for potential application of severe skin loss. Few systematic studies have been performed to examine the effect of varying fiber diameter electrospun fiber matrices for skin regeneration. The present study reports the fabrication of poly[lactic acid-co-glycolic acid] (PLAGA) matrices with fiber diameters of 150–225, 200–300, 250–467, 500–900, 600–1200, 2500–3000 and 3250–6000 nm via electrospinning. All fiber matrices found to have a tensile modulus from 39.23 ± 8.15 to 79.21 ± 13.71 MPa which falls in the range for normal human skin. Further, the porous fiber matrices have porosity between 38–60 % and average pore diameters between 10–14µm. We evaluated the efficacy of these biodegradable fiber matrices as skin substitutes by seeding them with human skin fibroblasts (hSF). Human skin fibroblasts acquired a well spread morphology and showed significant progressive growth on fiber matrices in the 350–1100 nm diameter range. Collagen type III gene expression was significantly up-regulated in hSF seeded on matrices with fiber diameters in the range of 350–1100 nm. Based on the need, the proposed fiber skin substitutes can be successfully fabricated and optimized for skin fibroblast attachment and growth. PMID:18639927

  13. Utilizing Matrix-Filler Interactions in the Design of Stimuli-Responsive, Mechanically-Adaptive Electrospun Composites

    NASA Astrophysics Data System (ADS)

    Wanasekara, Nandula; Stone, David; Wnek, Gary; Korley, Lashanda

    2013-03-01

    A new class of all-organic, stimuli-responsive and mechanically-adaptive electrospun nanocomposites, which have the ability to alter their stiffness upon hydration, were developed. These materials were fabricated by incorporating an electrospun mat of poly(vinyl alcohol) (PVA) as the filler in a polymeric matrix consisting of either poly(vinyl acetate) (PVAc) or ethylene oxide-epicholorohydrin copolymer (EO-EPI). The incorporation of high stiffness, high aspect ratio PVA filler mat significantly enhanced the tensile storage modulus of EO-EPI based composites, while modulus enhancement was only noticed above the glass transition for PVAc-based composites. Composite materials based on a rubbery EO-EPI host polymer and PVA filler exhibit an irreversible reduction by a factor of 12 of the tensile modulus upon hydration. In contrast, composites comprised of PVAc show a reversible reduction of modulus by a factor of 280 upon water uptake. The mechanical morphing of the electrospun composites is the result of the filler crystallinity, and matrix-filler interactions facilitated by the surface hydroxyl groups of the PVA filler. The choice of polymer matrix and electrospun nanofiber fillers allow control of matrix-filler interactions in a new series of all-organic composites to achieve desired stimuli-responsiveness and mechanical-adaptability upon exposure to various stimuli.

  14. Putting Electrospun Nanofibers to Work for Biomedical Research

    PubMed Central

    Xie, Jingwei; Li, Xiaoran; Xia, Younan

    2009-01-01

    Electrospinning has been exploited for almost one century to process polymers and related materials into nanofibers with controllable compositions, diameters, porosities, and porous structures for a variety of applications. Owing to its high porosity and large surface area, a non-woven mat of electrospun nanofibers can serve as an ideal scaffold to mimic the extracellular matrix for cell attachment and nutrient transportation. The nanofiber itself can also be functionalized through encapsulation or attachment of bioactive species such as extracellular matrix proteins, enzymes, and growth factors. In addition, the nanofibers can be further assembled into a variety of arrays or architectures by manipulating their alignment, stacking, or folding. All these attributes make electrospinning a powerful tool for generating nanostructured materials for a range of biomedical applications that include controlled release, drug delivery, and tissue engineering. PMID:20011452

  15. Promotion of initial anti-tumor effect via polydopamine modified doxorubicin-loaded electrospun fibrous membranes

    PubMed Central

    Yuan, Ziming; Zhao, Xin; Wang, Xiaohu; Qiu, Wangwang; Chen, Xinliang; Zheng, Qi; Cui, Wenguo

    2014-01-01

    Drug-loaded electrospun PLLA membranes are not conducive to adhesion between materials and tissues due to the strong hydrophobicity of PLLA, which possibly attenuate the drugs’ effect loaded on the materials. In the present work, we developed a facile method to improve the hydrophilicity of doxorubicin (DOX)-loaded electrospun PLLA fibrous membranes, which could enhance the anti-tumor effect at the early stage after implantation. A mussel protein, polydopamine (PDA), could be easily grafted on the surface of hydrophobic DOX-loaded electrospun PLLA membranes (PLLA-DOX/pDA) in water solution. The morphology analysis of PLLA-DOX/pDA fibers displayed that though the fiber diameter was slightly swollen, they still maintained a 3D fibrous structure, and the XPS analysis certified that pDA had successfully been grafted onto the surface of the fibers. The results of surface wettability analysis showed that the contact angle decreased from 136.7° to 0° after grafting. In vitro MTT assay showed that the cytotoxicity of PLLA-DOX/pDA fibers was the strongest, and the stereologic cell counting assay demonstrated that the adhesiveness of PLLA/pDA fiber was significantly better than PLLA fiber. In vivo tumor-bearing mice displayed that, after one week of implantation, the tumor apoptosis and necrosis of PLLA-DOX/pDA fibers were the most obvious from histopathology and TUNEL assay. The caspase-3 activity of PLLA-DOX/pDA group was the highest using biochemical techniques, and the Bax: Bcl-2 ratio increased significantly in PLLA-DOX/pDA group through qRT-PCR analysis. All the results demonstrated that pDA can improve the affinity of the electrospun PLLA membranes and enhance the drug effect on tumors. PMID:25337186

  16. Electrospun zwitterionic poly(sulfobetaine methacrylate) for nonadherent, superabsorbent, and antimicrobial wound dressing applications.

    PubMed

    Lalani, Reza; Liu, Lingyun

    2012-06-11

    Zwitterionic poly(sulfobetaine methacrylate) (PSBMA) has been well studied for its superhydrophilic and ultralow biofouling properties, making it a promising material for superabsorbent and nonadherent wound dressings. Electrospinning provides multiple desirable features for wound dressings, including high absorptivity due to high surface-area-to-volume ratio, high gas permeation, and conformability to contour of the wound bed. The goal of this work is to develop a fibrous membrane of PSBMA via electrospinning and evaluate its properties related to wound dressing applications. Being superhydrophilic, PSBMA fibers fabricated by a conventional electrospinning method would readily dissolve in water, whereas if cross-linker is added, the formation of hydrogel would prevent electrospinning. A three-step polymerization-electrospinning-photo-cross-linking process was developed in this work to fabricate the cross-linked electrospun PSBMA fibrous membrane. Such electrospun membrane was stable in water and exhibited high water absorption of 353% (w/w), whereas the PSBMA hydrogel only absorbed 81% water. The electrospun membrane showed strong resistance to protein adsorption and cell attachment. Bacterial adhesion studies using Gram negative P. aeruginosa and Gram positive S. epidermidis showed that the PSBMA electrospun membrane was also highly resistant to bacterial adhesion. The Ag(+)-impregnated electrospun PSBMA membrane was shown microbicidal, against both S. epidermidis and P. aeruginosa. Such electrospun PSBMA membrane is ideal for a novel type of nonadherent, superabsorbent, and antimicrobial wound dressing. The superior water absorption aids in fluid removal from highly exudating wounds while keeping the wound hydrated to support healing. Because of the resistance to protein, cell, and bacterial adhesion, the dressing removal will neither cause patients' pain nor disturb the newly formed tissues. The dressing also prevents the attachment of environmental bacteria

  17. Electrospun zwitterionic poly(sulfobetaine methacrylate) for nonadherent, superabsorbent, and antimicrobial wound dressing applications.

    PubMed

    Lalani, Reza; Liu, Lingyun

    2012-06-11

    Zwitterionic poly(sulfobetaine methacrylate) (PSBMA) has been well studied for its superhydrophilic and ultralow biofouling properties, making it a promising material for superabsorbent and nonadherent wound dressings. Electrospinning provides multiple desirable features for wound dressings, including high absorptivity due to high surface-area-to-volume ratio, high gas permeation, and conformability to contour of the wound bed. The goal of this work is to develop a fibrous membrane of PSBMA via electrospinning and evaluate its properties related to wound dressing applications. Being superhydrophilic, PSBMA fibers fabricated by a conventional electrospinning method would readily dissolve in water, whereas if cross-linker is added, the formation of hydrogel would prevent electrospinning. A three-step polymerization-electrospinning-photo-cross-linking process was developed in this work to fabricate the cross-linked electrospun PSBMA fibrous membrane. Such electrospun membrane was stable in water and exhibited high water absorption of 353% (w/w), whereas the PSBMA hydrogel only absorbed 81% water. The electrospun membrane showed strong resistance to protein adsorption and cell attachment. Bacterial adhesion studies using Gram negative P. aeruginosa and Gram positive S. epidermidis showed that the PSBMA electrospun membrane was also highly resistant to bacterial adhesion. The Ag(+)-impregnated electrospun PSBMA membrane was shown microbicidal, against both S. epidermidis and P. aeruginosa. Such electrospun PSBMA membrane is ideal for a novel type of nonadherent, superabsorbent, and antimicrobial wound dressing. The superior water absorption aids in fluid removal from highly exudating wounds while keeping the wound hydrated to support healing. Because of the resistance to protein, cell, and bacterial adhesion, the dressing removal will neither cause patients' pain nor disturb the newly formed tissues. The dressing also prevents the attachment of environmental bacteria

  18. Electrospun multifunctional tissue engineering scaffolds

    NASA Astrophysics Data System (ADS)

    Wang, Chong; Wang, Min

    2014-03-01

    Tissue engineering holds great promises in providing successful treatments of human body tissue loss that current methods are unable to treat or unable to achieve satisfactory clinical outcomes. In scaffold-based tissue engineering, a highperformance scaffold underpins the success of a tissue engineering strategy and a major direction in the field is to create multifunctional tissue engineering scaffolds for enhanced biological performance and for regenerating complex body tissues. Electrospinning can produce nanofibrous scaffolds that are highly desirable for tissue engineering. The enormous interest in electrospinning and electrospun fibrous structures by the science, engineering and medical communities has led to various developments of the electrospinning technology and wide investigations of electrospun products in many industries, including biomedical engineering, over the past two decades. It is now possible to create novel, multicomponent tissue engineering scaffolds with multiple functions. This article provides a concise review of recent advances in the R & D of electrospun multifunctional tissue engineering scaffolds. It also presents our philosophy and research in the designing and fabrication of electrospun multicomponent scaffolds with multiple functions.

  19. Influence of self-assembly regenerated silk fibroin nanofibers on the properties of electrospun materials.

    PubMed

    Zhao, Huijing; Ren, Xia; Zhang, Yi; Huang, Lei

    2015-01-01

    In this study, self-assembly regenerated silk fibroin (RSF) nanofibers were prepared and observed by Atomic Force Microscope (AFM). Then RSF films containing nanospheres and nanofibers were prepared and dissolved with poly (L-lactide-co-ε-caprolactone) (PLCL) with a blending ratio of 30/70 in hexafluoro-2-propanol (HFIP). In order to determine whether different nanostructures in the solution influence the morphological, structural, and mechanical properties of the final electrospun materials, flat membranes were prepared and characterized by Scanning Electron Microscope (SEM), Fourier Transform Infrared (FT-IR), and mechanical testing. The secondary structure of as-spun materials with RSF nanofibers were not changed, however, the diameter of electrospun fibers decreased and tensile strength and elongation at breaks increased. Electrospun materials with RSF nanofibers have the potential to be used for skin, cartilage, and blood vessels because of their biocompatibility and improved mechanical properties.

  20. Influence of self-assembly regenerated silk fibroin nanofibers on the properties of electrospun materials.

    PubMed

    Zhao, Huijing; Ren, Xia; Zhang, Yi; Huang, Lei

    2015-01-01

    In this study, self-assembly regenerated silk fibroin (RSF) nanofibers were prepared and observed by Atomic Force Microscope (AFM). Then RSF films containing nanospheres and nanofibers were prepared and dissolved with poly (L-lactide-co-ε-caprolactone) (PLCL) with a blending ratio of 30/70 in hexafluoro-2-propanol (HFIP). In order to determine whether different nanostructures in the solution influence the morphological, structural, and mechanical properties of the final electrospun materials, flat membranes were prepared and characterized by Scanning Electron Microscope (SEM), Fourier Transform Infrared (FT-IR), and mechanical testing. The secondary structure of as-spun materials with RSF nanofibers were not changed, however, the diameter of electrospun fibers decreased and tensile strength and elongation at breaks increased. Electrospun materials with RSF nanofibers have the potential to be used for skin, cartilage, and blood vessels because of their biocompatibility and improved mechanical properties. PMID:26406088

  1. Electrospinning of caseinates to create protective fibrous mats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Electrospinning is a nonthermal process that produces fibers on the micron- or nano-scale from a polymer solution. If produced by electrospinning of biopolymer solutions, fibrous mats may be created for protecting foods and allowing for the preservation and controlled release of bioactives for healt...

  2. Electrospinning of caseinates to create protective fibrous mats

    Technology Transfer Automated Retrieval System (TEKTRAN)

    JUSTIFICATION Electrospinning is a nonthermal process that produces fibers with diameters on the micron- or nano-scales from a polymer solution. If produced by electrospinning of biopolymer solutions, fibrous mats may be created for protecting foods, improving food quality and allowing for the prese...

  3. Suspended, Shrinkage-Free, Electrospun PLGA Nanofibrous Scaffold for Skin Tissue Engineering.

    PubMed

    Ru, Changhai; Wang, Feilong; Pang, Ming; Sun, Lining; Chen, Ruihua; Sun, Yu

    2015-05-27

    Electrospinning is a technique for creating continuous nanofibrous networks that can architecturally be similar to the structure of extracellular matrix (ECM). However, the shrinkage of electrospun mats is unfavorable for the triggering of cell adhesion and further growth. In this work, electrospun PLGA nanofiber assemblies are utilized to create a scaffold. Aided by a polypropylene auxiliary supporter, the scaffold is able to maintain long-term integrity without dimensional shrinkage. This scaffold is also able to suspend in cell culture medium; hence, keratinocyte cells seeded on the scaffold are exposed to air as required in skin tissue engineering. Experiments also show that human skin keratinocytes can proliferate on the scaffold and infiltrate into the scaffold. PMID:25941905

  4. Suspended, Shrinkage-Free, Electrospun PLGA Nanofibrous Scaffold for Skin Tissue Engineering.

    PubMed

    Ru, Changhai; Wang, Feilong; Pang, Ming; Sun, Lining; Chen, Ruihua; Sun, Yu

    2015-05-27

    Electrospinning is a technique for creating continuous nanofibrous networks that can architecturally be similar to the structure of extracellular matrix (ECM). However, the shrinkage of electrospun mats is unfavorable for the triggering of cell adhesion and further growth. In this work, electrospun PLGA nanofiber assemblies are utilized to create a scaffold. Aided by a polypropylene auxiliary supporter, the scaffold is able to maintain long-term integrity without dimensional shrinkage. This scaffold is also able to suspend in cell culture medium; hence, keratinocyte cells seeded on the scaffold are exposed to air as required in skin tissue engineering. Experiments also show that human skin keratinocytes can proliferate on the scaffold and infiltrate into the scaffold.

  5. Aligned Electrospun Scaffolds and Elastogenic Factors for Vascular Cell-Mediated Elastic Matrix Assembly

    PubMed Central

    Bashur, Chris A.; Ramamurthi, Anand

    2011-01-01

    Strategies to enhance the production of organized elastic matrix by smooth muscle cells (SMCs) are critical in engineering functional vascular conduits. Therefore, the goal of this study was to determine the effect of different surfaces (i.e. random and aligned electrospun poly(ε-caprolactone) meshes and two-dimensional controls) and exogenous elastogenic factors on cultured rat aortic SMC phenotype and production of extracellular matrix. This study demonstrated that aligned electrospun fibers guide cell alignment, induce a more elongated cell morphology, and promote a more synthetic phenotype. Importantly, these cells produced greater amounts of elastin-rich matrix per cell on the electrospun scaffolds. In addition, exogenous elastogenic factors severely limited RASMC proliferation and promoted a more synthetic SMC phenotype on electrospun meshes, but they had less effect on two-dimensional controls. Finally, the elastogenic factors induced the SMCs to generate more matrix collagen and elastin on a per cell basis. Together, these results demonstrate the elastogenic benefits of electrospun meshes. PMID:21953981

  6. Stress-strain dependence for soy-protein nanofiber mats

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

    Soy protein/nylon 6 monolithic and core-shell nanofibers were solution-blown and collected on a rotating drum as fiber mats. Tensile tests of rectangular strips of these mats revealed their stress-strain dependences. These dependences were linear at low strains which correspond to their elastic behavior. Then, a plastic-like nonlinearity sets in, which is followed by catastrophic rupture. Parameters such as Young's modulus, yield stress, and specific strain energy were measured. The results were rationalized in the framework of the phenomenological elastic-plastic model, as well as a novel micromechanical model (the latter attributes plasticity to bond rapture between the individual overstressed fibers in the mat). Besides, the effects of stretching history, rate of stretching, and winding velocity of the collector drum on the strength-related parameters are studied. The results for soy protein/nylon 6 nanofiber mats are also compared to those for solution blown pure nylon 6 mats, which were produced and tested in the same way.

  7. The Photovoltaic Performances of PVdF-HFP Electrospun Membranes Employed Quasi-Solid-State Dye Sensitized Solar Cells.

    PubMed

    Gnana kumar, G; Balanay, Mannix P; Nirmala, R; Kim, Dong Hee; Raj kumar, T; Senthilkumar, N; Kim, Ae Rhan; Yoo, Dong Jin

    2016-01-01

    The PVdF-HFP nanofiber membranes with different molecular weight were prepared by electrospinning technique and were investigated as solid state electrolyte membranes in quasi solid state dye sensitized solar cells (QS-DSSC). The homogeneously distributed and fully interconnected nanofibers were obtained for all of the prepared PVdF-HFP electrospun membranes and the average fiber diameters of fabricated membranes were dependent upon the molecular weight of polymer. The thermal stability of electrospun PVdF-HFP membrane was decreased with a decrement of molecular weight, specifying the high heat transfer area of small diameter nanofibers. The QS-DSSC fabricated with the lower molecular weight PVdF-HFP electrospun nanofiber membrane exhibited the power conversion efficiency of 1 = 5.38%, which is superior over the high molecular weight membranes and is comparable with the liquid electrolyte. Furthermore, the electrospun PVdF-HFP membrane exhibited long-term durability over the liquid electrolyte, owing to the higher adsorption and retention efficiencies of liquid electrolyte in its highly porous and interconnected nanofibers. Thus the proposed electrospun PVdF-HFP membrane effectively tackled the volatilization and leakage of liquid electrolyte and provided good photoconversion efficiency associated with an excellent stability, which constructs the prepared electrospun membranes as credible solid state candidates for the application of QS-DSSCs. PMID:27398491

  8. Antimicrobial PLGA ultrafine fibers: interaction with wound bacteria.

    PubMed

    Said, Somiraa S; Aloufy, Affaf K; El-Halfawy, Omar M; Boraei, Nabila A; El-Khordagui, Labiba K

    2011-09-01

    The structure and functions of polymer nanofibers as wound dressing materials have been well investigated over the last few years. However, during the healing process, nanofibrous mats are inevitably involved in dynamic interactions with the wound environment, an aspect not explored yet. Potential active participation of ultrafine fibers as wound dressing material in a dynamic interaction with wound bacteria has been examined using three wound bacterial strains and antimicrobial fusidic acid (FA)-loaded electrospun PLGA ultrafine fibers (UFs). These were developed and characterized for morphology and in-use pharmaceutical attributes. In vitro microbiological studies showed fast bacterial colonization of UFs and formation of a dense biofilm. Interestingly, bacterial stacks on UFs resulted in a remarkable enhancement of drug release, which was associated with detrimental changes in morphology of UFs in addition to a decrease in pH of their aqueous incubation medium. In turn, UFs by allowing progressively faster release of bioactive FA eradicated planktonic bacteria and considerably suppressed biofilm. Findings point out the risk of wound reinfection and microbial resistance upon using non-medicated or inadequately medicated bioresorbable fibrous wound dressings. Equally important, data strongly draw attention to the importance of characterizing drug delivery systems and establishing material-function relationships for biomedical applications under biorelevant conditions.

  9. Development of polyamide-6,6/chitosan electrospun hybrid nanofibrous scaffolds for tissue engineering application.

    PubMed

    Shrestha, Bishnu Kumar; Mousa, Hamouda M; Tiwari, Arjun Prasad; Ko, Sung Won; Park, Chan Hee; Kim, Cheol Sang

    2016-09-01

    The development of biofunctional and bioactive hybrid polymeric scaffolds seek to mitigate the current challenges in the emerging field of tissue engineering. In this paper, we report the fabrication of a biomimetic and biocompatible nanofibrous scaffolds of polyamide-6,6 (PA-6,6) blended with biopolymer chitosan via one step co-electrospinning technique. Different weight percentage of chitosan 10wt%, 15wt%, and 20wt% were blended with PA-6,6, respectively. The nanocomposite electrospun scaffolds mats enabled to provide the osteophilic environment for cells growth and biomineralization. The morphological and physiochemical properties of the resulted scaffolds were studied using field-emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), and Fourier transform-infrared (FT-IR) spectroscopy. The improvement in hydrophilicity and mechanical strength of the bio-nanocomposite mesh with 20wt% chitosan embedded, was the desired avenue for adhesion, proliferation and maturation of osteoblast cells as compared to other sample groups and pure PA-6,6 fibrous mat. The biomineralization of the nanocomposite electrospun mats also showed higher ability to nucleate bioactive calcium phosphate (Ca/P) nanoparticles comparing to pristine PA-6,6. Furthermore, the biomimetic nature of scaffolds exhibited the cells viability and regeneration of pre-osteoblast (MC3T3-E1) cells which were assessed via in vitro cell culture test. Collectively, the results suggested that the optimized 20wt% of chitosan supplemented hybrid electrospun fibrous scaffold has significant effect in biomedical field to create osteogenic capabilities for tissue engineering. PMID:27185121

  10. Structural and Cellular Characterization of Electrospun Recombinant Human Tropoelastin Biomaterials1

    PubMed Central

    McKenna, Kathryn A.; Gregory, Kenton W.; Sarao, Rebecca C.; Maslen, Cheryl L.; Glanville, Robert W.; Hinds, Monica T.

    2012-01-01

    An off-the-shelf vascular graft biomaterial for vascular bypass surgeries is an unmet clinical need. The vascular biomaterial must support cell growth, be non-thrombogenic, minimize intimal hyperplasia, match the structural properties of native vessels, and allow for regeneration of arterial tissue. Electrospun recombinant human tropoelastin (rTE) as a medial component of a vascular graft scaffold was investigated in this study by evaluating its structural properties, as well as its ability to support primary smooth muscle cell adhesion and growth. rTE solutions of 9, 15, and 20 wt% concentrations were electropun into sheets with average fiber diameters of 167 ± 32, 522 ± 67, and 735 ± 270 nm, and average pore sizes of 0.4 ± 0.1, 5.8 ± 4.3, and 4.9 ± 2.4 μm, respectively. Electrospun rTE fibers were cross-linked with disuccinimidyl suberate (DSS) to produce an insoluble fibrous polymeric recombinant tropoelastin (prTE) biomaterial. The smooth muscle cells attached via integrin binding. The proliferation of the smooth muscle cells on the electrospun prTE biomaterial was comparable to growth on prTE coated glass, glass alone and tissue culture plastic. Electrospun tropoelastin demonstrated the cell compatibility and design flexibility required of a graft biomaterial for vascular applications. PMID:21586601

  11. Size-dependent behavior of electrospun polymer nanofibers under small deformation

    NASA Astrophysics Data System (ADS)

    Arinstein, Arkadii; Zussman, Eyal

    2011-03-01

    A model describing a mechanism resulting in size-dependent behavior of electrospun polymer nanofibers under small deformation is proposed. According this model, the polymer matrix of the nanofibers consists of correlated groups of chains/subchains, partially orientated along the fiber. These supermolecular structures which were formed during electrospinning are confined by the fiber boundary. Thus, when the fiber elongates under external force the relative rotations of these correlated regions are hindered. As a result the elastic modulus depends on the diameter of the deformed fiber. In case of small fiber diameters this restriction is dominant while this effect decreases with increase of fiber diameter, and tends to zero for large fiber diameters according to square-law which was verified by experimental observations.

  12. Functional Reactive Polymer Electrospun Matrix.

    PubMed

    Agarwal, Vipul; Ho, Dominic; Ho, Diwei; Galabura, Yuriy; Yasin, Faizah; Gong, Peijun; Ye, Weike; Singh, Ruhani; Munshi, Alaa; Saunders, Martin; Woodward, Robert C; St Pierre, Timothy; Wood, Fiona M; Fear, Mark; Lorenser, Dirk; Sampson, David D; Zdyrko, Bogdan; Luzinov, Igor; Smith, Nicole M; Iyer, K Swaminathan

    2016-02-01

    Synthetic multifunctional electrospun composites are a new class of hybrid materials with many potential applications. However, the lack of an efficient, reactive large-area substrate has been one of the major limitations in the development of these materials as advanced functional platforms. Herein, we demonstrate the utility of electrospun poly(glycidyl methacrylate) films as a highly versatile platform for the development of functional nanostructured materials anchored to a surface. The utility of this platform as a reactive substrate is demonstrated by grafting poly(N-isopropylacrylamide) to incorporate stimuli-responsive properties. Additionally, we demonstrate that functional nanocomposites can be fabricated using this platform with properties for sensing, fluorescence imaging, and magneto-responsiveness. PMID:26780245

  13. Electrospun Vascular Grafts with Improved Compliance Matching to Native Vessels

    PubMed Central

    Nezarati, Roya M.; Eifert, Michelle B.; Dempsey, David K.; Cosgriff-Hernandez, Elizabeth

    2014-01-01

    Coronary artery bypass grafting (CABG) is one of the most commonly performed major surgeries in the United States. Autologous vessels such as the saphenous vein are the current gold standard for treatment; however, synthetic vascular prostheses made of expanded poly(tetrafluoroethylene) (ePTFE) or poly(ethylene terephthalate) (PET) are used when autologous vessels are unavailable. These synthetic grafts have a high failure rate in small diameter (<4 mm) applications due to rapid re-occlusion via intimal hyperplasia. Current strategies to improve clinical performance are focused on preventing intimal hyperplasia by fabricating grafts with compliance and burst pressure similar to native vessels. To this end, we have developed an electrospun vascular graft from segmented polyurethanes with tunable properties by altering material chemistry and graft microarchitecture. Relationships between polyurethane tensile properties and biomechanical properties were elucidated to select polymers with desirable properties. Graft thickness, fiber tortuosity, and fiber fusions were modulated to provide additional tools for controlling graft properties. Using a combination of these strategies, a vascular graft with compliance and burst pressure exceeding the saphenous vein autograft was fabricated (compliance = 6.0 ± 0.6 %/mmHg × 10−4, burst pressure = 2260 ± 160 mmHg). This graft is hypothesized to reduce intimal hyperplasia associated with low compliance in synthetic grafts and improve long term clinical success. Additionally, the fundamental relationships between electrospun mesh microarchitecture and mechanical properties identified in this work can be utilized in various biomedical applications. PMID:24846218

  14. Processing-structure-property studies of: (I) submicron polymeric fibers produced by electrospinning and (II) films of linear low density polyethylenes as influenced by the short chain branch length in copolymers of ethylene/1-butene, ethylene/1-hexene and ethylene/1-octene synthesized by a single site metallocene catalyst

    NASA Astrophysics Data System (ADS)

    Gupta, Pankaj

    The overall theme of the research discussed in this dissertation has been to explore processing-structure-property relationships for submicron polymeric fibers produced by electrospinning (Part I) and to ascertain whether or not the length of the short chain branch has any effect on the physical properties of films of linear low-density polyethylenes (LLDPEs) (Part II). The research efforts discussed in Part I of this dissertation relate to some fundamental as well as more applied investigations involving electrospinning. These include investigating the effects of solution rheology on fiber formation and developing novel methodologies to fabricate polymeric mats comprising of high specific surface submicron fibers of more than one polymer, high chemical resistant substrates produced by in situ photo crosslinking during electrospinning, superparamagnetic flexible substrates by electrospinning a solution of an elastomeric polymer containing ferrite nanoparticles of Mn-Zn-Ni and substrates for filtration applications. Bicomponent electrospinning of poly(vinyl chloride)-polyurethane and poly(vinylidiene fluoride)-polyurethane was successfully performed. In addition, filtration properties of single and bicomponent electrospun mats of polyacrylonitrile and polystyrene were investigated. Results indicated lower aerosol penetration or higher filtration efficiencies of the filters based on submicron electrospun fibers in comparison to the conventional filter materials. In addition, Part II of this dissertation explores whether or not the length of the short chain branch affects the physical properties of blown and compression molded films of LLDPEs that were synthesized by a single site metallocene catalyst. Here, three resins based on copolymers of ethylene/1-butene, ethylene/1-hexene, and ethylene/1-octene were utilized that were very similar in terms of their molecular weight and distribution, melt rheology, density, crystallinity and short chain branching content and

  15. Activation of lactoperoxidase system in milk by glucose oxidase immobilized in electrospun polylactide microfibers.

    PubMed

    Zhou, Y; Lim, L-T

    2009-03-01

    In this study, glucose oxidase (GOX) was immobilized in polylactide (PLA) fibers that were used to activate the lactoperoxidase (LP) system in milk. The GOX-containing microfibers were electrospun from emulsions prepared by dispersing aqueous GOX in PLA dissolved in a chloroform and N,N-dimethylformamide blend, using sorbitan monopalmitate as an emulsifier. The enzymatic activity of GOX-in-PLA fibers (1100 +/- 400 nm diameter) was more than 19 times higher than that of the GOX-in-PLA membrane formed by direct casting, due to the larger surface area of the electrospun fibers. The activation of LP in model solutions using GOX-in-PLA fibers provided a more sustained generation of antimicrobial OSCN(-) than direct activation using H(2)O(2). Preliminary evaluation on milk samples showed that the electrospun GOX-in-PLA microfibers are capable of activating the naturally present LP system, indicating that they may be promising for active food packaging applications to extend the shelf life of milk.

  16. Activation of lactoperoxidase system in milk by glucose oxidase immobilized in electrospun polylactide microfibers.

    PubMed

    Zhou, Y; Lim, L-T

    2009-03-01

    In this study, glucose oxidase (GOX) was immobilized in polylactide (PLA) fibers that were used to activate the lactoperoxidase (LP) system in milk. The GOX-containing microfibers were electrospun from emulsions prepared by dispersing aqueous GOX in PLA dissolved in a chloroform and N,N-dimethylformamide blend, using sorbitan monopalmitate as an emulsifier. The enzymatic activity of GOX-in-PLA fibers (1100 +/- 400 nm diameter) was more than 19 times higher than that of the GOX-in-PLA membrane formed by direct casting, due to the larger surface area of the electrospun fibers. The activation of LP in model solutions using GOX-in-PLA fibers provided a more sustained generation of antimicrobial OSCN(-) than direct activation using H(2)O(2). Preliminary evaluation on milk samples showed that the electrospun GOX-in-PLA microfibers are capable of activating the naturally present LP system, indicating that they may be promising for active food packaging applications to extend the shelf life of milk. PMID:19323732

  17. Compositions of constructed microbial mats

    DOEpatents

    Bender, Judith A.; Phillips, Peter C.

    1999-01-01

    Compositions and methods of use of constructed microbial mats, comprising cyanobacteria and purple autotrophic bacteria and an organic nutrient source, in a laminated structure, are described. The constructed microbial mat is used for bioremediation of different individual contaminants and for mixed or multiple contaminants, and for production of beneficial compositions and molecules.

  18. M.A.T. Programs.

    ERIC Educational Resources Information Center

    Wildman, Louis

    A proposal is presented for developing a Master of Arts in Teaching (MAT) program at California State University, Bakersfield. The criteria for a MAT program are examined by outlining existing programs at: (1) Harvard Graduate School; (2) University of California, Berkeley; (3) Portland State University; (4) Stanford University; (5) University of…

  19. Hospital use of decontaminating mats.

    PubMed

    Marchetti, M G; Finzi, G; Cugini, P; Manfrini, M; Salvatorelli, G

    2003-09-01

    Decontaminating mats made of several layers of adhesive sheets (water-based acrylic 6 g/m2) supplemented with a bactericidal agent (3-1 benzoisothiazolin) at a concentration of 25% were placed in the passages providing access to the operating rooms of an orthopaedic service. Contact plates containing tryptone soy agar were used to assess bacterial concentration at specific points in front of and beyond the mats. For trolley passageways two areas were defined: central and lateral paths, corresponding to the areas walked upon by the personnel pushing the trolleys and to the paths covered by the trolley wheels, respectively. In order to exclude a simple mechanical effect, a comparison of bacterial loads at defined sites beyond the mats was carried out in the presence and in the absence of decontaminating mats. Bacterial colony counts in the presence of decontaminating mats were substantially and statistically significantly reduced compared with the absence of mats. The lower mean number of colony-forming units detected at points located beyond the mats parallels this finding; this difference is also statistically significant. We thus conclude that decontaminating mats are potentially useful in decreasing micro-organism carry-over due to personnel or the passage of trolleys into areas at high risk of infection such as operating rooms.

  20. In-vitro release of fragrant l-carvone from electrospun poly(ϵ-caprolactone)/wheat cellulose scaffold.

    PubMed

    Ramamoorthy, Manjula; Rajiv, Sheeja

    2015-11-20

    The release kinetics of l-carvone loaded from electrospun poly(ϵ-caprolactone) (PCL) and Wheat cellulose (WC) blend were studied. WC was extracted from wheat straw, a cost effective agricultural waste by the acid hydrolysis method. A homogeneous solution of PCL-WC (13:3wt%) was optimized to produce beadless electrospun PCL-WC blend nanofibers. Further, WC and the prepared electrospun PCL-WC blend fibers were systematically characterized by ATR-FTIR, SEM, XRD, TGA, DTGA, and DSC measurements. The hydrophilic character of the blend fibers was analysed using swelling tests and contact angle measurements. The loading efficiency of l-carvone into the electrospun PCL-WC blend fibers was evaluated to be ∼70%. The in-vitro release of l-carvone from PCL-WC blend fibers followed Korsmeyer-Peppas kinetic model indicating the diffusion mechanism and the maximum release of l-carvone was found to be ∼84% over a period of 30h. These results would offer the prepared PCL-WC blend as an ideal fibrous mesh for fragrant antimicrobial textile applications. PMID:26344288

  1. MueMat Multicrid Toolbox

    2010-11-23

    MueMat is intended for the research and development of multigrid algorithms used in the solution of sparse linear systems arising from systems of partial differential equations. The software can generate example linear systems and provides short programs to demonstrate the various interfaces for creating, accessing, and applying the solvers. MueMat currently includes two types of algebraic multigrid methods and many commonly used smoothers. However, the software is intended to be extensible, and new methods canmore » be incorporated easily. MueMat also allows for advanced usage, such as combining multiple methods and segregated solves. The library supports point and block access to matrix data. MueMat has been designed for use within the programming environment of the Mathworks program MATLAB®. All algorithms and methods in MueMat have been or will be published in the open scientific literature.« less

  2. MueMat Multicrid Toolbox

    SciTech Connect

    2010-11-23

    MueMat is intended for the research and development of multigrid algorithms used in the solution of sparse linear systems arising from systems of partial differential equations. The software can generate example linear systems and provides short programs to demonstrate the various interfaces for creating, accessing, and applying the solvers. MueMat currently includes two types of algebraic multigrid methods and many commonly used smoothers. However, the software is intended to be extensible, and new methods can be incorporated easily. MueMat also allows for advanced usage, such as combining multiple methods and segregated solves. The library supports point and block access to matrix data. MueMat has been designed for use within the programming environment of the Mathworks program MATLAB®. All algorithms and methods in MueMat have been or will be published in the open scientific literature.

  3. Fabrication and Biocompatibility of Electrospun Silk Biocomposites

    PubMed Central

    Wei, Kai; Kim, Byoung-Suhk; Kim, Ick-Soo

    2011-01-01

    Silk fibroin has attracted great interest in tissue engineering because of its outstanding biocompatibility, biodegradability and minimal inflammatory reaction. In this study, two kinds of biocomposites based on regenerated silk fibroin are fabricated by electrospinning and post-treatment processes, respectively. Firstly, regenerated silk fibroin/tetramethoxysilane (TMOS) hybrid nanofibers with high hydrophilicity are prepared, which is superior for fibroblast attachment. The electrospinning process causes adjacent fibers to ‘weld’ at contact points, which can be proved by scanning electron microscope (SEM). The water contact angle of silk/tetramethoxysilane (TMOS) composites shows a sharper decrease than pure regenerated silk fibroin nanofiber, which has a great effect on the early stage of cell attachment behavior. Secondly, a novel tissue engineering scaffold material based on electrospun silk fibroin/nano-hydroxyapatite (nHA) biocomposites is prepared by means of an effective calcium and phosphate (Ca–P) alternate soaking method. nHA is successfully produced on regenerated silk fibroin nanofiber within several min without any pre-treatments. The osteoblastic activities of this novel nanofibrous biocomposites are also investigated by employing osteoblastic-like MC3T3-E1 cell line. The cell functionality such as alkaline phosphatase (ALP) activity is ameliorated on mineralized silk nanofibers. All these results indicate that this silk/nHA biocomposite scaffold material may be a promising biomaterial for bone tissue engineering. PMID:24957869

  4. Electrospun Gallium Nitride Nanofibers

    SciTech Connect

    Melendez, Anamaris; Morales, Kristle; Ramos, Idalia; Campo, Eva; Santiago, Jorge J.

    2009-04-19

    The high thermal conductivity and wide bandgap of gallium nitride (GaN) are desirable characteristics in optoelectronics and sensing applications. In comparison to thin films and powders, in the nanofiber morphology the sensitivity of GaN is expected to increase as the exposed area (proportional to the length) increases. In this work we present electrospinning as a novel technique in the fabrication of GaN nanofibers. Electrospinning, invented in the 1930s, is a simple, inexpensive, and rapid technique to produce microscopically long ultrafine fibers. GaN nanofibers are produced using gallium nitrate and dimethyl-acetamide as precursors. After electrospinning, thermal decomposition under an inert atmosphere is used to pyrolyze the polymer. To complete the preparation, the nanofibers are sintered in a tube furnace under a NH{sub 3} flow. Both scanning electron microscopy and profilometry show that the process produces continuous and uniform fibers with diameters ranging from 20 to a few hundred nanometers, and lengths of up to a few centimeters. X-ray diffraction (XRD) analysis shows the development of GaN nanofibers with hexagonal wurtzite structure. Future work includes additional characterization using transmission electron microscopy and XRD to understand the role of precursors and nitridation in nanofiber synthesis, and the use of single nanofibers for the construction of optical and gas sensing devices.

  5. Influence of electrospun scaffolds prepared from distinct polymers on proliferation and viability of endothelial cells

    SciTech Connect

    Matveeva, V. G. Antonova, L. V. Velikanova, E. A.; Sergeeva, E. A.; Krivkina, E. O.; Glushkova, T. V.; Kudryavtseva, Yu. A.; Barbarash, O. L.; Barbarash, L. S.

    2015-10-27

    We compared electrospun nonwoven scaffolds from polylactic acid (PLA), polycaprolactone (PCL), and polyhydroxybutyrate/valerate (PHBV)/polycaprolactone (PHBV/PCL). The surface of PHBV/PCL and PCL scaffolds was highly porous and consisted of randomly distributed fibers, whilst the surface of PLA scaffolds consisted of thin straight fibers, which located more sparsely, forming large pores. Culture of EA.hy 926 endothelial cells on these scaffolds during 7 days and further fluorescent microscopy demonstrated that the surface of PHBV/PCL scaffolds was most favorable for efficient adhesion, proliferation, and viability of endothelial cells. The lowest proliferation rate and cell viability were detected on PLA scaffolds. Therefore, PHBV/PCL electrospun nonwoven scaffolds demonstrated the best results regarding endothelial cell proliferation and viability as compared to PCL and PLA scaffolds.

  6. Influence of electrospun scaffolds prepared from distinct polymers on proliferation and viability of endothelial cells

    NASA Astrophysics Data System (ADS)

    Matveeva, V. G.; Antonova, L. V.; Velikanova, E. A.; Sergeeva, E. A.; Krivkina, E. O.; Glushkova, T. V.; Kudryavtseva, Yu. A.; Barbarash, O. L.; Barbarash, L. S.

    2015-10-01

    We compared electrospun nonwoven scaffolds from polylactic acid (PLA), polycaprolactone (PCL), and polyhydroxybutyrate/valerate (PHBV)/polycaprolactone (PHBV/PCL). The surface of PHBV/PCL and PCL scaffolds was highly porous and consisted of randomly distributed fibers, whilst the surface of PLA scaffolds consisted of thin straight fibers, which located more sparsely, forming large pores. Culture of EA.hy 926 endothelial cells on these scaffolds during 7 days and further fluorescent microscopy demonstrated that the surface of PHBV/PCL scaffolds was most favorable for efficient adhesion, proliferation, and viability of endothelial cells. The lowest proliferation rate and cell viability were detected on PLA scaffolds. Therefore, PHBV/PCL electrospun nonwoven scaffolds demonstrated the best results regarding endothelial cell proliferation and viability as compared to PCL and PLA scaffolds.

  7. Biocomposites electrospun with poly(ε-caprolactone) and silk fibroin powder for biomedical applications.

    PubMed

    Lee, Hyeongjin; Kim, GeunHyung

    2010-01-01

    Biomedical synthetic polymers have been used in soft and hard tissue regeneration because of their good processability and biodegradability. However, biomaterials such as poly(ε-caprolactone) (PCL) have various shortcomings, including intrinsic hydrophobicity and lack of bioactive functional groups. The material must be reinforced with natural biomaterials to achieve good cellular and mechanical performance as biomedical material. We fabricated a biocomposite using PCL and silk fibroin (SF) powder, which has good biocompatibility and mechanical properties. The hydrophilicity, mechanical properties and cellular behavior of the PCL/SF fibers were analyzed. In addition, we obtained a highly oriented conduit of electrospun biocomposite fibers by modifying the rolling collector of the electrospinning system. As the alignment of micro/nanofibers increased, the orthotropic mechanical properties were improved. The biocompatibility of the biocomposite was evaluated in a culture of bone-marrow-derived rat mesenchymal stem cells. The cellular result demonstrated the potential usefulness of electrospun biocomposites for various biomedical conduit systems. PMID:20537249

  8. Radiotherapeutic bandage based on electrospun polyacrylonitrile containing holmium-166 iron garnet nanoparticles for the treatment of skin cancer.

    PubMed

    Munaweera, Imalka; Levesque-Bishop, Daniel; Shi, Yi; Di Pasqua, Anthony J; Balkus, Kenneth J

    2014-12-24

    Radiation therapy is used as a primary treatment for inoperable tumors and in patients that cannot or will not undergo surgery. Radioactive holmium-166 ((166)Ho) is a viable candidate for use against skin cancer. Nonradioactive holmium-165 ((165)Ho) iron garnet nanoparticles have been incorporated into a bandage, which, after neutron-activation to (166)Ho, can be applied to a tumor lesion. The (165)Ho iron garnet nanoparticles ((165)HoIG) were synthesized and introduced into polyacrylonitrile (PAN) polymer solutions. The polymer solutions were then electrospun to produce flexible nonwoven bandages, which are stable to neutron-activation. The fiber mats were characterized using scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis and inductively coupled plasma mass spectrometry. The bandages are stable after neutron-activation at a thermal neutron-flux of approximately 3.5 × 10(12) neutrons/cm(2)·s for at least 4 h and 100 °C. Different amounts of radioactivity can be produced by changing the amount of the (165)HoIG nanoparticles inside the bandage and the duration of neutron-activation, which is important for different stages of skin cancer. Furthermore, the radioactive bandage can be easily manipulated to irradiate only the tumor site by cutting the bandage into specific shapes and sizes that cover the tumor prior to neutron-activation. Thus, exposure of healthy cells to high energy β-particles can be avoided. Moreover, there is no leakage of radioactive material after neutron activation, which is critical for safe handling by healthcare professionals treating skin cancer patients.

  9. Radiotherapeutic bandage based on electrospun polyacrylonitrile containing holmium-166 iron garnet nanoparticles for the treatment of skin cancer.

    PubMed

    Munaweera, Imalka; Levesque-Bishop, Daniel; Shi, Yi; Di Pasqua, Anthony J; Balkus, Kenneth J

    2014-12-24

    Radiation therapy is used as a primary treatment for inoperable tumors and in patients that cannot or will not undergo surgery. Radioactive holmium-166 ((166)Ho) is a viable candidate for use against skin cancer. Nonradioactive holmium-165 ((165)Ho) iron garnet nanoparticles have been incorporated into a bandage, which, after neutron-activation to (166)Ho, can be applied to a tumor lesion. The (165)Ho iron garnet nanoparticles ((165)HoIG) were synthesized and introduced into polyacrylonitrile (PAN) polymer solutions. The polymer solutions were then electrospun to produce flexible nonwoven bandages, which are stable to neutron-activation. The fiber mats were characterized using scanning electron microscopy, transmission electron microscopy, powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis and inductively coupled plasma mass spectrometry. The bandages are stable after neutron-activation at a thermal neutron-flux of approximately 3.5 × 10(12) neutrons/cm(2)·s for at least 4 h and 100 °C. Different amounts of radioactivity can be produced by changing the amount of the (165)HoIG nanoparticles inside the bandage and the duration of neutron-activation, which is important for different stages of skin cancer. Furthermore, the radioactive bandage can be easily manipulated to irradiate only the tumor site by cutting the bandage into specific shapes and sizes that cover the tumor prior to neutron-activation. Thus, exposure of healthy cells to high energy β-particles can be avoided. Moreover, there is no leakage of radioactive material after neutron activation, which is critical for safe handling by healthcare professionals treating skin cancer patients. PMID:25396281

  10. Nanofiber alignment of a small diameter elastic electrospun scaffold

    NASA Astrophysics Data System (ADS)

    Patel, Jignesh

    Cardiovascular disease is the leading cause of death in western countries with coronary heart disease making up 50% of these deaths. As a treatment option, tissue engineered grafts have great potential. Elastic scaffolds that mimic arterial extracellular matrix (ECM) may hold the key to creating viable vascular grafts. Electrospinning is a widely used scaffold fabrication technique to engineer tubular scaffolds. In this study, we investigated how the collector rotation speed altered the nanofiber alignment which may improve mechanical characteristics making the scaffold more suitable for arterial grafts. The scaffold was fabricated from a blend of PCL/Elastin. 2D Fast Fourier Transform (FFT) image processing tool and MatLab were used to quantitatively analyze nanofiber orientation at different collector speeds (13500 to 15500 rpm). Both Image J and MatLab showed graphical peaks indicating predominant fiber orientation angles. A collector speed of 15000 rpm was found to produce the best nanofiber alignment with narrow peaks at 90 and 270 degrees, and a relative amplitude of 200. This indicates a narrow distribution of circumferentially aligned nanofibers. Collector speeds below and above 15000 rpm caused a decrease in fiber alignment with a broader orientation distribution. Uniformity of fiber diameter was also measured. Of 600 measures from the 15000 rpm scaffolds, the fiber diameter range from 500 nm to 899 nm was most prevalent. This diameter range was slightly larger than native ECM which ranges from 50 nm to 500 nm. The second most prevalent diameter range had an average of 404 nm which is within the diameter range of collagen. This study concluded that with proper electrospinning technique and collector speed, it is possible to fabricate highly aligned small diameter elastic scaffolds. Image J 2D FFT results confirmed MatLab findings for the analyses of circumferentially aligned nanofibers. In addition, MatLab analyses simplified the FFT orientation data

  11. Vascularization and cellular isolation potential of a novel electrospun cell delivery vehicle.

    PubMed

    Krishnan, Laxminarayanan; Touroo, Jeremy; Reed, Robert; Boland, Eugene; Hoying, James B; Williams, Stuart K

    2014-07-01

    A clinical need exists for a cell delivery device that supports long-term cell viability, cell retention within the device and retrieval of delivered cells if necessary. Previously, cell isolation devices have been based on hollow fiber membranes, porous polymer scaffolds, alginate systems, or micro-machined membranes. We present the development and characterization of a novel dual porosity electrospun membrane based device, which supports cellular infiltration and vascularization of its outer porous layer and maintains cellular isolation within a lumen bounded by an inner low porosity layer. Electrospinning conditions were initially established to support electrospun fiber deposition onto nonconductive silicone surfaces. With these parameters established, devices for in vivo evaluations were produced using nylon as a nonconductive scaffold for deposition of dual porosity electrospun fibers. The outer porous layer supported the development of a penetrating microcirculation and the membrane supported the transfer of insulin from encapsulated sustained release pellets for 4 weeks. Viable cells implanted within the device could be identified after 2 weeks of implantation. Through the successful demonstration of survival and cellular isolation of human epithelial cells within the implanted devices and the ability to use the device to deliver insulin, we have established the utility of this device toward localized cell transplantation. The cell delivery device establishes a platform to test the feasibility of approaches to cell dose control and cell localization at the site of implantation in the clinical use of modified autologous or allogeneic cells. PMID:23913805