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Sample records for electrospun fiber mats

  1. Mechanical behavior, modeling, and color change of electrospun fiber mats

    NASA Astrophysics Data System (ADS)

    Pedicini, Angelo

    The process of electrospinning and the physical properties of electrospun fibers are presented in this thesis. In electrospinning, polymeric fibers having diameters ranging from 50 nanometers to 1 micrometer are prepared by applying high static charge to a polymer solution. The mechanical properties and molecular morphology of some electrospun polymers are shown to be fundamentally different compared to their bulk analogs. Experimental results indicate that the mechanical behavior of electrospun polyurethane fiber mats is influenced by fiber mat morphology, molecular orientation, and surface flaws on electrospun fibers. This research characterizes the mechanical behavior of randomly oriented electrospun polyurethane mats and sheds light on general differences in behavior between electrospun and bulk materials. Further, the mechanical response of random fiber mats is modeled based on the mechanical characterization of aligned electrospun fibers. Also, empirical models are employed to relate the tensile properties of electrospun materials to their bulk analogs. The crystallinity and melting behavior of a family of electrospun polyesters is studied and provides insight to the rapid cooling and effects on solidification and crystallization of electrospun polymeric fibers. The results indicate a commonly accepted idea in electrospinning, that electrospun fibers result from rapid solvent evaporation and experience quench-like solidification from a jet of polymer solution. A qualitative study illustrates a color change phenomenon in a series of electrospun polymer/solvent systems. Color change is produced by electrospinning, and subsequent heating, and occurs at characteristic temperatures dependent on the polymer system used. These color change systems are also demonstrated as candidates for imageable media.

  2. Cellulose acetate electrospun fiber mats for controlled release of silymarin.

    PubMed

    Phiriyawirut, Manisara; Phaechamud, Thawatchai

    2012-01-01

    In this research, the silymarin-loaded electrospun cellulose acetate (CA) fibers were prepared which containing silymarin in various amounts (i.e., 2.5-20 wt.% based on the weight of CA powder). Incorporation of silymarin in the neat CA solution did not affect the morphology of the resulting fibers, as both the neat and the silymarin-loaded CA fibers were smooth. The average diameters of silymarin-loaded CA fiber ranged between 550-900 nm. No presence of the silymarin aggregates of any kind was observed on the surfaces of these fibers, suggesting that the silymarin was encapsulated well within the fibers. These results were confirmed by lowering the glass transition temperature and the melting temperature of the silymarin-loaded electrospun CA fibers which is determined by DSC technique. The release characteristic of silymarin from the silymarin-loaded CA fiber mats was investigated by the total immersion in the solution of 1/1 phosphate buffer/methanol medium pH 7.4 at 37 degrees C. The silymarin release from the silymarin-loaded electrospun CA fiber mat is monotonously increased to reach the maximum value at 480 min. The maximum amount of silymarin released from these materials increases with the increasing of initial silymarin loading in the spinning CA solutions. Since no aggregation of silymarin was found on the surface of the silymarin-loaded fibers, the release of the silymarin from fiber mats was mainly by the diffusion.

  3. Cell Attachment to Hydrogel-Electrospun Fiber Mat Composite Materials

    PubMed Central

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

    2012-01-01

    Hydrogels, electrospun fiber mats (EFMs), and their composites have been extensively studied for tissue engineering because of their physical and chemical similarity to native biological systems. However, while chemically similar, hydrogels and electrospun fiber mats display very different topographical features. Here, we examine the influence of surface topography and composition of hydrogels, EFMs, and hydrogel-EFM composites on cell behavior. Materials studied were composed of synthetic poly(ethylene glycol) (PEG) and poly(ethylene glycol)-poly(ε-caprolactone) (PEGPCL) hydrogels and electrospun poly(caprolactone) (PCL) and core/shell PCL/PEGPCL constituent materials. The number of adherent cells and cell circularity were most strongly influenced by the fibrous nature of materials (e.g., topography), whereas cell spreading was more strongly influenced by material composition (e.g., chemistry). These results suggest that cell attachment and proliferation to hydrogel-EFM composites can be tuned by varying these properties to provide important insights for the future design of such composite materials. PMID:24955629

  4. Increasing Mechanical Properties of 2-D-Structured Electrospun Nylon 6 Non-Woven Fiber Mats

    PubMed Central

    Xiang, Chunhui; Frey, Margaret W.

    2016-01-01

    Tensile strength, Young’s modulus, and toughness of electrospun nylon 6 non-woven fiber mats were improved by increasing individual nanofiber strength and fiber–fiber load sharing. Single-walled carbon nanotubes (CNTs) were used as reinforcement to increase the strength of the electrospun nylon 6 nanofibers. Young’s modulus, tensile strength, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % solutions increased 51%, 87%, and 136%, respectively, after incorporating 1 wt % CNTs into the nylon 6 nanofibers. Three methods were investigated to enhance fiber–fiber load sharing: increasing friction between fibers, thermal bonding, and solvent bonding. The addition of beaded nylon 6 nanofibers into the non-woven fiber mats to increase fiber-fiber friction resulted in a statistically significantly increase in Young’s modulus over comparable smooth non-woven fiber mats. After annealing, tensile strength, elongation, and toughness of the nylon 6 non-woven fiber mats electrospun from 20 wt % + 10 wt % solutions increased 26%, 28%, and 68% compared to those from 20 wt % solutions. Solvent bonding with formic acid vapor at room temperature for 30 min caused increases of 56%, 67%, and 39% in the Young’s modulus, tensile strength, and toughness of non-woven fiber mats, respectively. The increases attributed to increased individual nanofiber strength and solvent bonding synergistically resulted in the improvement of Young’s modulus of the electrospun nylon 6 non-woven fiber mats. PMID:28773397

  5. 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

  6. High areal capacity Si/LiCoO2 batteries from electrospun composite fiber mats

    DOE PAGES

    Self, Ethan C.; Naguib, Michael Abdelmalak; Ruther, Rose E.; ...

    2017-03-09

    Freestanding nanofiber mat Li–ion battery anodes containing Si nanoparticles, carbon black, and poly(acrylic acid) (Si/C/PAA) are prepared using electrospinning. The mats are compacted to a high fiber volume fraction (≈0.85), and interfiber contacts are welded by exposing the mat to methanol vapor. A compacted+welded fiber mat anode containing 40 wt % Si exhibits high capacities of 1484 mA h g–1 (3500 mA h gmath formula ) at 0.1 C and 489 mA h g–1 at 1 C and good cycling stability (e.g., 73 % capacity retention over 50 cycles). Post-mortem analysis of the fiber mats shows that the overall electrodemore » structure is preserved during cycling. Whereas many nanostructured Si anodes are hindered by their low active material loadings and densities, thick, densely packed Si/C/PAA fiber mat anodes reported here have high areal and volumetric capacities (e.g., 4.5 mA h cm–2 and 750 mA h cm–3, respectively). A full cell containing an electrospun Si/C/PAA anode and electrospun LiCoO2-based cathode has a high specific energy density of 270 Wh kg–1. Here, the excellent performance of the electrospun Si/C/PAA fiber mat anodes is attributed to the: i) PAA binder, which interacts with the SiOx surface of Si nanoparticles and ii) high material loading, high fiber volume fraction, and welded interfiber contacts of the electrospun mats.« less

  7. High Areal Capacity Si/LiCoO2 Batteries from Electrospun Composite Fiber Mats.

    PubMed

    Self, Ethan C; Naguib, Michael; Ruther, Rose E; McRen, Emily C; Wycisk, Ryszard; Liu, Gao; Nanda, Jagjit; Pintauro, Peter N

    2017-04-22

    Freestanding nanofiber mat Li-ion battery anodes containing Si nanoparticles, carbon black, and poly(acrylic acid) (Si/C/PAA) are prepared using electrospinning. The mats are compacted to a high fiber volume fraction (≈0.85), and interfiber contacts are welded by exposing the mat to methanol vapor. A compacted+welded fiber mat anode containing 40 wt % Si exhibits high capacities of 1484 mA h g(-1) (3500 mA h g-1Si ) at 0.1 C and 489 mA h g(-1) at 1 C and good cycling stability (e.g., 73 % capacity retention over 50 cycles). Post-mortem analysis of the fiber mats shows that the overall electrode structure is preserved during cycling. Whereas many nanostructured Si anodes are hindered by their low active material loadings and densities, thick, densely packed Si/C/PAA fiber mat anodes reported here have high areal and volumetric capacities (e.g., 4.5 mA h cm(-2) and 750 mA h cm(-3) , respectively). A full cell containing an electrospun Si/C/PAA anode and electrospun LiCoO2 -based cathode has a high specific energy density of 270 Wh kg(-1) . The excellent performance of the electrospun Si/C/PAA fiber mat anodes is attributed to the: i) PAA binder, which interacts with the SiOx surface of Si nanoparticles and ii) high material loading, high fiber volume fraction, and welded interfiber contacts of the electrospun mats. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Transient Fiber Mats of Electrospun Poly(Propylene Carbonate) Composites with Remarkable Mechanical Strength.

    PubMed

    Ohlendorf, Peter; Ruyack, Alexander; Leonardi, Amanda; Shi, Chengjian; Cuppoletti, Christine; Bruce, Ian; Lal, Amit; Ober, Christopher K

    2017-08-02

    Polymers with a triggered decomposition are attractive for an array of applications ranging from patterning to transient packaging materials, as well as for environmental protection. This work showed for the first time UV and thermally triggered transience in fiber mats using poly(propylene carbonate) (PPC) composites. The electrospun PPC-composite fiber mats combine excellent decomposition performance (because of the high surface to volume ratio) with high stiffness and thus represent a new class of materials enabling innovative applications, such as transient filter materials and short-time plant protection materials, as well as temporary lightweight materials for aerospace engineering. Thermally and UV-triggerable additives (protected acids or base) have been used in different concentrations to tune the transience performance of the fiber mats over a wide range (75-212 °C). The addition of organo-modified clay (OMMT) enhanced mechanical stability and prevented shrinkage at room temperature. Different annealing methods have been used to improve the mechanical properties even further (tensile strength = 2-12 MPa, Young's modulus = 55-747 MPa) making these fiber mats attractive for a broad field of applications. An Ashby plot of Young's modulus versus degradation temperature for electrospun fiber mats is shown, revealing much lower degradation temperatures with higher moduli for PPC composites compared to other electrospun polymers.

  9. 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

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

    PubMed

    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.

  11. 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

  12. Electrospun poly(vinyl alcohol) fiber mats as carriers for extracts from the fruit hull of mangosteen.

    PubMed

    Opanasopit, Praneet; Ruktanonchai, Uracha; Suwantong, Orawan; Panomsuk, Suwannee; Ngawhirunpat, Tanasait; Sittisombut, Chavalit; Suksamran, Tittaya; Supaphol, Pitt

    2008-01-01

    Electrospinning is a process used to produce ultrafine fibers with diameters in the nanometer range. Electrospun fiber mats have high potentials for biomedical uses, due to their high surface area and ease of drug incorporation into the fibers. They can be used as carriers for drug delivery and can enhance drug release and skin permeability. The aim of this study was to prepare electrospun fiber mats and to incorporate extracts from the fruit hull of mangosteen. Antioxidant activity and extract release were determined and compared between the extract incorporated in the electrospun fiber mats and in the cast films. Poly(vinyl alcohol) (PVA) was selected as the polymer matrix. Extracts in the amount of 2.5%, 5%, and 10% w/w, based on the weight of PVA, were incorporated with 10% w/w PVA to finally obtain electrospun fiber mats and cast films. The extract content was evaluated by antioxidative activity using the 2,2-diphenyl-1-picryhydrazyl (DPPH) method. The morphology of the electrospun fiber mats was analyzed using a scanning electron microscope (SEM). The results showed that the diameters of the fibers were in nanoscales and that no crystal of the extract was found at any concentration of the extract. The extract contents in the electrospun fiber mats prepared at 2.5%, 5%, and 10% w/w of the extract were 9.6%, 9.7%, and 10.8% of the initial loading concentration, respectively, whereas, those in the cast films were 23.9%, 14.5%, and 21.0%, respectively. The release of the extract from the electrospun fiber mats prepared at 2.5%, 5%, and 10% w/w of the extract at 120 min were 73.2%, 83.6%, and 81.3% w/w, respectively. However, much slower release from the cast films was observed (i.e., 4.3%, 29.1%, and 40.8% w/w, respectively).

  13. Highly hydrophobic electrospun fiber mats from polyisobutylene-based thermoplastic elastomers.

    PubMed

    Lim, Goy Teck; Puskas, Judit E; Reneker, Darrell H; Jákli, Antal; Horton, Walter E

    2011-05-09

    This paper is the first report of electrospinning neat polyisobutylene-based thermoplastic elastomers. Two generations of these materials are investigated: a linear poly(styrene-b-isobutylene-b-styrene) (L_SIBS) triblock copolymer and a dendritic poly(isobutylene-b-p-methylstyrene) (D_IB-MS), also a candidate for biomedical applications. Cross-polarized optical microscopy shows birefringence, indicating orientation in the electrospun fibers, which undergo large elongation and shear during electrospinning. In contrast to the circular cross section of L_SIBS fibers, D_IB-MS yields dumbbell-shaped fiber cross sections for the combination of processing conditions, molecular weight, and architecture. Hydrophobic surfaces with a water contact angle as high as 146 ± 3° were obtained with D_IB-MS that had the noncircular fiber cross section and a hierarchical arrangement of nano- to micrometer-sized fibers in the mat. These highly water repellent fiber mats were found to serve as an excellent scaffold for bovine chondrocytes to produce cartilage tissue.

  14. 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.

  15. 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.

  16. Preparation and transdermal diffusion evaluation of the prazosin hydrochloride-loaded electrospun poly(vinyl alcohol) fiber mats.

    PubMed

    Shen, Xiaobing; Xu, Qian; Xu, Shi; Li, Jie; Zhang, Niping; Zhang, Ling

    2014-07-01

    This study reports on the use of electrospun polyvinyl alcohol (PVA) nanofiber mats loaded with prazosin hydrochloride (PRH) as a transdermal drug delivery system, investigating the morphology of electrospun PVA nanofibers, the in vitro release characteristics of the drug from the as-spun fibers, and the influence of permeation enhancer (water-resoluble azone, WSA) on transdermal diffusion of PRH through a rat skin. The same was also conducted on the PRH -loaded as-cast PVA films for comparison. Results indicated that the morphology of PRH-loaded PVA fibers observed by scanning electron microscopy (SEM) relied on the electrospinning processing parameters, and the addition of WSA had obvious effects on the diameter and morphology of electrospun PVA fibers. The PRH-loaded electrospun PVA fiber mats exhibited much higher accumulated release dose and release rate of PRH than as-cast PVA films. And WAS can improve the release amount and rate of PRH from drug-loaded samples. The content of PRH in receiver was more than that in the stratum corneum and in the dermis. It was concluded that the PRH-loaded electropun PVA fiber mats as a transdermal patches can be a promising candidate for the conventional preparation.

  17. Antimicrobial activity of electrospun poly(butylenes succinate) fiber mats containing PVP-capped silver nanoparticles.

    PubMed

    Tian, Ligang; Wang, Pingli; Zhao, Zhiguo; Ji, Junhui

    2013-12-01

    In this study, biodegradable poly(butylenes succinate) (PBS) fiber mats containing silver nanoparticles (AgNPs) were prepared by the electrospinning process. Small AgNPs (<10 nm) were simply synthesized using polyvinylpyrrolidone as the capping agent as well as the reductant. The morphology of the PBS-AgNPs fiber mats and the distribution of the AgNPs were well characterized by TEM and SEM. The release of Ag from the PBS fiber mats was quantitively determined by ICP. The PBS fiber mats with 0.29 % AgNPs content showed strong antimicrobial activity against both gram-positive Staphylococcus aureus and gram-negative Escherichia coli with the efficacy as high as 99 %. The effective bactericidal activity on E. coli was demonstrated for a short contacting time with the PBS-AgNPs fiber mats. In addition, the long-term release performance of Ag from the fiber mats can keep inhibiting the bacterial growth in the mats over a long period of time.

  18. Design and in vitro evaluation of transdermal patches based on ibuprofen-loaded electrospun fiber mats.

    PubMed

    Shi, Yongli; Xu, Shuxin; Dong, Anjie; Zhang, Jianhua

    2013-02-01

    To improve the poor compatibility among different components of Drug-in-adhesive type patch, two novel plasters (Drug-in-fiber and Drug-in-adhesive/fiber) were developed based on ibuprofen (IBU)-loaded fiber mats. These fibrous mats were fabricated via electrospinning of cellulose acetate/poly(vinylpyrrolidone) composites in a binary solvent of N,N-dimethyl acetamide/acetone. Physical status studies suggested that Drug-in-fiber could inhibit IBU re-crystallization, but the active ingredients were released at a relatively slow rate due to the dual-resistance of fiber mat and adhesive matrix. To overcome this shortcoming, Drug-in-adhesive/fiber was designed by coupling medicated hydrophilic pressure sensitive adhesive and IBU-loaded fiber mat. This method endowed Drug-in-adhesive/fiber a fast IBU release rate and high permeated drug amount though simulative skins. This design separated enhancer from adhesive matrix, which guaranteed Drug-in-adhesive/fiber excellent adhesion forces. Hence, the plasters based on medicated fiber mats improved the compatibility among patch components.

  19. Ester prodrug-loaded electrospun cellulose acetate fiber mats as transdermal drug delivery systems.

    PubMed

    Wu, Xiao-mei; Branford-White, Christopher J; Zhu, Li-min; Chatterton, Nichoals P; Yu, Deng-guang

    2010-08-01

    Cellulose acetate (CA) fibers loaded with the ester prodrugs of naproxen, including methyl ester, ethyl ester and isopropyl ester, were prepared through electrospinning using acetone/N,N-dimethylacetamide(DMAc)/ethanol (4:1:1, v/v/v) as solvent. The chemical and morphological characterizations of the medicated fibers were investigated by means of SEM, DSC, XRD and FTIR, as well as the studies of the drug release properties. The results indicated that the morphology and diameter of the fibers were influenced by the concentration of spinning solution, applied voltage, electrospun solvent and the surfactants. The average diameters of the fibers ranged between 100 and 500 nm for three prodrugs. There was good compatibility between CA and three prodrugs in the blended fibers, respectively. In vitro release indicated that constant drug release from the fiber was observed over 6 days. The prodrugs were successfully encapsulated into the fibers, and this system was stable in terms of effectiveness in release.

  20. 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.

  1. In vitro biological evaluation of electrospun cellulose acetate fiber mats containing asiaticoside or curcumin.

    PubMed

    Suwantong, Orawan; Ruktanonchai, Uracha; Supaphol, Pitt

    2010-09-15

    Ultra-fine cellulose acetate (CA; M(w) approximately 30,000 Da; degree of acetyl substitution approximately 2.4) fiber mats containing either asiaticoside [from the plant Centella asiatica (L.); either in the form of a crude extract (CACE) or pure substance (PAC)] or curcumin (CM; from the plant Curcuma longa L.) were successfully prepared. The proposed use of these materials is as topical/transdermal patches or wound dressings. Here, the potential for use of these herb-loaded CA fiber mats as wound dressings was evaluated in terms of the stability and the antioxidant activity of the as-loaded herbal substances, the ability to support both the attachment and the proliferation of fibroblasts and the ability of the cultured fibroblasts to synthesize collagen. Normal human dermal fibroblasts (NHDF) were used as the reference fibroblastic cells. The results showed that the as-loaded herbal substances were stable even after the herb-loaded CA fiber mats had been aged either at room temperature or at 40 degrees C for a period of up to 4 months. The inclusion of asiaticoside [either 2% (w/w) CACE or 40% (w/w) PAC] rendered the resulting CA fiber mats their superiority in supporting the attachment, promoting the proliferation, and upregulating the production of collagen of the seeded and/or the cultured NHDF to the corresponding solvent-cast films and the neat CA fiber mats. On the other hand, the presence of CM imparted the antioxidant activity to the resulting CA fiber mats.

  2. Influence of the protocol used for fibroin extraction on the mechanical properties and fiber sizes of electrospun silk mats.

    PubMed

    Aznar-Cervantes, Salvador D; Vicente-Cervantes, Daniel; Meseguer-Olmo, Luis; Cenis, José L; Lozano-Pérez, A Abel

    2013-05-01

    Silk fibroin (SF) was regenerated using three of the most common protocols described in the bibliography for the dissolution of raw SF (LiBr 9.3M, CaCl2 50 wt.% or CaCl2:EtOH:H2O 1:2:8 in molar ratio). The integrity of regenerated SF in aqueous solution was analyzed by SDS-PAGE and different profiles of degradation were observed depending on the protocol used. This fact was found to affect also the aqueous solubility of the freeze dried protein. These different SFs were used to produce electrospun mats using SF solutions of SF 17 wt.% in 1,1,1,1',1',1'-hexafluoro-2-propanol (HFIP) and significant differences in fiber sizes, elongation and ultimate strength values were found. This work provides a global overview of the manner that different methods of SF extraction can affect the properties of electrospun SF-mats and consequently it should be considered depending on the use they are going to be made for.

  3. Prominent reinforcing effect of chitin nanocrystals on electrospun polydioxanone nanocomposite fiber mats.

    PubMed

    Zhu, Lei; Liang, Kai; Ji, Yali

    2015-04-01

    The ultra-strong nanocomposite fiber mats based on biodegradable polydioxanone (PDO) and chitin nanocrystals (ChiNCs) were successfully prepared by means of electrospinning. The ChiNCs are uniformly dispersed in the PDO matrix and mostly oriented along fiber long axis, resulting in a significant improvement in mechanical property. Moreover, the introduction of ChiNCs led to the increase of the glass-transition temperature (Tg) and thermal decomposition temperature (Td) of PDO elucidated by thermal analyses. In addition, the loading of ChiNCs caused very different In vitro degradation behavior compared to neat PDO fiber mat. Furthermore, in vitro cell culture results indicated that the addition of ChiNCs improved the cellular adhesion and proliferation.

  4. 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.

  5. 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

  6. Antibacterial properties of tough and strong electrospun PMMA/PEO fiber mats filled with Lanasol--a naturally occurring brominated substance.

    PubMed

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

    2014-09-09

    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.

  7. 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.

  8. Effect of adhesive on the morphology and mechanical properties of electrospun fibrous mat of cellulose acetate.

    PubMed

    Baek, Woo-Il; Pant, Hem Raj; Nam, Ki-Taek; Nirmala, R; Oh, Hyun-Ju; Kim, Il; Kim, Hak-Yong

    2011-09-27

    Ultrafine fibers of cellulose acetate/poly(butyl acrylate) (CA/PBA) composite in which PBA acted as an adhesive and CA acted as a matrix, were successfully prepared as fibrous mat via electrospinning. The morphology observation from the electrospun CA/PBA composite fibers, after treatment with heat hardener, revealed that the fibers were cylindrical and had point-bonded structures. SEM, FT-IR spectra, Raman spectra, TGA analysis, and mechanical properties measurement were used to study the different properties of hybrid mats. The tensile strength of blend fibrous electrospun mats was found to be effectively increased. This resultant enhancement of the mechanical properties of polymer fibrous mats, caused by generating the point-bonded structures (due to adhesive), could increase the number of potential applications of mechanically weak electrospun CA fibers.

  9. Applications of electrospun fibers.

    PubMed

    Lu, Ping; Ding, Bin

    2008-01-01

    The simplicity of the electrospinning fabrication process, the diversity of electrospinnable materials, and the unique features associated with electrospun fibers make this technique and resultant structures attractive for various applications. The past few years witnessed the significant progresses in the application areas of electrospun fibers, which were demonstrated by the numbers of the recent published patents on electrospinning. It is very apparent that the current focus has been shifted from studying the modification of the electrospinning conditions and apparatus for obtaining fibers with different sizes, shapes, morphologies, structures, alignments before 2000 to looking for the possible applications of these resultant nanofibers with broad functionalities after 2001. The current paper presents a systematic review on the recent applications of electrospun nanofibers in a broad range of fields including biomedical applications such as drug delivery, tissue engineering, wound dressing and cosmetics, functional materials and devices such as composite reinforcement, filters, protective clothing and smart textiles, and energy and electronics such as batteries/cells and capacitors, sensors and catalysts. Although some of these applications may be still remained in the laboratory in the current stage, plenty of successful examples have proved that electrospun nanofibers have a bright future in a variety of industries.

  10. Preparation and characterization of caffeic acid-grafted electrospun poly(L-lactic acid) fiber mats for biomedical applications.

    PubMed

    Chuysinuan, Piyachat; Pavasant, Prasit; Supaphol, Pitt

    2012-06-27

    Caffeic acid (CA) was chemically immobilized onto the surfaces of the individual electrospun poly(l-lactic acid) (PLLA) fibers to enhance the hydrophilicity and impart the antioxidant activity to the obtained fibrous membranes. This was done in two sequential steps. First, amino groups were covalently introduced onto the surfaces through the reaction with 1,6-hexamethylenediamine (HMD). In the second step, the amino moieties reacted with CA, which had been preactivated sequentially with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS). The success of the reactions was confirmed by the ninhydrin assay and X-ray photoelectron spectroscopic analysis (XPS). Indirect cytotoxicity evaluation with murine dermal fibroblasts (L929) and human dermal fibroblasts (HDFa) revealed that the neat and the modified PLLA fibrous matrices released no substances in the levels that were harmful to the cells. Direct culturing of HDFa on these fibrous substrates indicated that they supported the proliferation of the cells on days 2 and 3 very well and that the CA-immobilized substrates exhibited the highest cell viability. Lastly, the antioxidant activity of the CA-immobilized substrates, as revealed by the 1,1-diphenyl-2-picryldrazyl (DPPH) radical scavenging assay, was as high as 88% on average.

  11. 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.

  12. Nano/micro electro-spun polyethylene terephthalate fibrous mat preparation and characterization.

    PubMed

    Hadjizadeh, Afra; Ajji, Abdellah; Bureau, Martin N

    2011-04-01

    Electro-spun polyethylene terephthalate (PET) fibrous mats are potential substrates for biotechnological and biomedical applications. In this regard, substrate characteristics including, fiber diameter, orientation and mechanical properties play an important role in controlling the interaction of substrate with biological entities. However, few studies reporting the preparation of electro-spun PET substrates with such controlled characteristics have been published. In this study, electro-spun PET fibrous mats with fiber diameters in the nanometer and micrometer range were produced by varying polymer solution concentration and flow rate. Fiber orientation within the mats was also varied by varying collector surface velocities in rotation and translation. Their morphological, mechanical, thermal and structural properties were evaluated as a function of fiber diameter and collector speed using scanning electron microscopy (SEM), a micromechanical tester, differential scanning calorimetry (DSC) and X-ray diffraction (XRD), respectively. Varying polymer solution concentration and flow rate allowed the production of matrices with fiber diameters ranging from 400 nm to 2 μm. Tensile properties increased with fiber diameter and collector surface velocity. Thermal properties of electro-spun PET fibers were different from the structure of as received raw PET in the form of pellets, revealing an amorphous structure for the entire electro-spun PET. This was also confirmed by XRD analysis. No considerable differences were observed between electro-spun PET fibers, in terms of crystalline and thermal properties, produced under various conditions. These electro-spun mats with different fiber diameters, orientation and mechanical properties can be used for various applications including tissue engineering scaffolds.

  13. Antifouling Electrospun Nanofiber Mats Functionalized with Polymer Zwitterions.

    PubMed

    Kolewe, Kristopher W; Dobosz, Kerianne M; Rieger, Katrina A; Chang, Chia-Chih; Emrick, Todd; Schiffman, Jessica D

    2016-10-06

    In this study, we exploit the excellent fouling resistance of polymer zwitterions and present electrospun nanofiber mats surface functionalized with poly(2-methacryloyloxyethyl phosphorylcholine) (polyMPC). This zwitterionic polymer coating maximizes the accessibility of the zwitterion to effectively limit biofouling on nanofiber membranes. Two facile, scalable methods yielded a coating on cellulose nanofibers: (i) a two-step sequential deposition featuring dopamine polymerization followed by the physioadsorption of polyMPC, and (ii) a one-step codeposition of polydopamine (PDA) with polyMPC. While the sequential and codeposited nanofiber mat assemblies have an equivalent average fiber diameter, hydrophilic contact angle, surface chemistry, and stability, the topography of nanofibers prepared by codeposition were smoother. Protein and microbial antifouling performance of the zwitterion modified nanofiber mats along with two controls, cellulose (unmodified) and PDA coated nanofiber mats were evaluated by dynamic protein fouling and prolonged bacterial exposure. Following 21 days of exposure to bovine serum albumin, the sequential nanofiber mats significantly resisted protein fouling, as indicated by their 95% flux recovery ratio in a water flux experiment, a 300% improvement over the cellulose nanofiber mats. When challenged with two model microbes Escherichia coli and Staphylococcus aureus for 24 h, both zwitterion modifications demonstrated superior fouling resistance by statistically reducing microbial attachment over the two controls. This study demonstrates that, by decorating the surfaces of chemically and mechanically robust cellulose nanofiber mats with polyMPC, we can generate high performance, free-standing nanofiber mats that hold potential in applications where antifouling materials are imperative, such as tissue engineering scaffolds and water purification technologies.

  14. Wrinkled surface topographies of electrospun polymer fibers

    NASA Astrophysics Data System (ADS)

    Wang, Lifeng; Pai, Chia-Ling; Boyce, Mary C.; Rutledge, Gregory C.

    2009-04-01

    Electrospun polymer fibers are shown to have wrinkled surface topographies that result from buckling instabilities during processing. A glassy shell forms on the surface of the gel-like core during solvent evaporation; continued evaporation leads to a contraction mismatch between the core and shell that triggers buckling of the shell. The wrinkled topographies are quantified in terms of the critical buckling wave number and wavelength. The results explain the observed wrinkled topographies and provide a framework for designing fibers with high specific surface areas and textured/patterned surface topographies to enhance surface dominated properties in fibers and fibrous mats.

  15. 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

  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 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.

  18. 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. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Robust superhydrophobic mats based on electrospun crystalline nanofibers combined with a silane precursor.

    PubMed

    Park, Song Hee; Lee, Song Min; Lim, Ho Sun; Han, Joong Tark; Lee, Dong Ryeol; Shin, Hwa Sung; Jeong, Youngjin; Kim, Jooyong; Cho, Jeong Ho

    2010-03-01

    We demonstrate the fabrication of solvent-resistant, mechanically robust, superhydrophobic nanofibrous mats by electrospinning of poly(vinylidene fluoride) (PVDF) in the presence of inorganic silane materials. The solvent resistance and mechanical strength of nanofibrous mats were dramatically increased through the crystallization of as-spun PVDF fibers or incorporation of a tetraethyl orthosilicate (TEOS) sol into the nanofibrous matrix. The electrospun nanofibrous mats yielded a water contact angle of 156 degrees that did not vary with TEOS content. The solvent resistance and mechanical robustness of the electrospun mats were significantly enhanced through extensive cross-linking of TEOS, even after short PVDF annealing times. The interpenetrating polymer network, which embeds polymer chains in a TEOS network, allows the fabrication of robust functional nanofibers by combining semicrystalline polymers with electrospinning techniques.

  20. Melt-blown and electrospun drug-loaded polymer fiber mats for dissolution enhancement: a comparative study.

    PubMed

    Balogh, Attila; Farkas, Balázs; Faragó, Kornél; Farkas, Attila; Wagner, István; Van Assche, Ivo; Verreck, Geert; Nagy, Zsombor K; Marosi, György

    2015-05-01

    Melt blowing (MB) was investigated to prepare a fast dissolving fibrous drug-loaded solid dispersion and compared with solvent-based electrospinning (SES) and melt electrospinning (MES). As a conventional solvent-free technique coupled with melt extrusion and using a high-speed gas stream, MB can provide high-quality micro- and nanofibers at industrial throughput levels. Carvedilol, a weak-base model drug with poor water solubility, was processed using a common composition optimized for the fiber spinning and blowing methods based on a hydrophilic vinylpyrrolidone-vinyl acetate copolymer (PVPVA64) and PEG 3000 plasticizer. Scanning electron microscopy combined with fiber diameter analysis showed diameter distributions characteristic to each prepared fibrous fabrics (the mean value increased toward SESfibers exhibited ultrafast drug release tested under neutral pH conditions; the melt-blown sample dissolved within 2 min owing to its large specific surface area. The presented results confirm the applicability of MB as a novel formulation technique for polymer-based drug delivery systems.

  1. Antimicrobial Electrospun Biopolymer Nanofiber Mats Functionalized with Graphene Oxide-Silver Nanocomposites.

    PubMed

    de Faria, Andreia F; Perreault, François; Shaulsky, Evyatar; Arias Chavez, Laura H; Elimelech, Menachem

    2015-06-17

    Functionalization of electrospun mats with antimicrobial nanomaterials is an attractive strategy to develop polymer coating materials to prevent bacterial colonization on surfaces. In this study we demonstrated a feasible approach to produce antimicrobial electrospun mats through a postfabrication binding of graphene-based nanocomposites to the nanofibers' surface. A mixture of poly(lactide-co-glycolide) (PLGA) and chitosan was electrospun to yield cylindrical and narrow-diameter (356 nm) polymeric fibers. To achieve a robust antimicrobial property, the PLGA-chitosan mats were functionalized with graphene oxide decorated with silver nanoparticles (GO-Ag) via a chemical reaction between the carboxyl groups of graphene and the primary amine functional groups on the PLGA-chitosan fibers using 3-(dimethylamino)propyl-N'-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide as cross-linking agents. The attachment of GO-Ag sheets to the surface of PLGA-chitosan fibers was successfully revealed by scanning and transmission electron images. Upon direct contact with bacterial cells, the PLGA-chitosan mats functionalized with GO-Ag nanocomposites were able to effectively inactivate both Gram-negative (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. Our results suggest that covalent binding of GO-Ag nanocomposites to the surface of PLGA-chitosan mats opens up new opportunities for the production of cost-effective, scalable, and biodegradable coating materials with the ability to hinder microbial proliferation on solid surfaces.

  2. Electrospun chitosan-based nanocomposite mats reinforced with chitin nanocrystals for wound dressing.

    PubMed

    Naseri, Narges; Algan, Constance; Jacobs, Valencia; John, Maya; Oksman, Kristiina; Mathew, Aji P

    2014-08-30

    The aim of this study was to develop electrospun chitosan/polyethylene oxide-based randomly oriented fiber mats reinforced with chitin nanocrystals (ChNC) for wound dressing. Microscopy studies showed porous mats of smooth and beadless fibers with diameters between 223 and 966 nm. The addition of chitin nanocrystals as well as crosslinking had a positive impact on the mechanical properties of the mats, and the crosslinked nanocomposite mats with a tensile strength of 64.9 MPa and modulus of 10.2 GPa were considered the best candidate for wound dressing application. The high surface area of the mats (35 m(2)g(-1)) was also considered beneficial for wound healing. The water vapor transmission rate of the prepared mats was between 1290 and 1,548 gm(-2)day(-1), and was in the range for injured skin or wounds. The electrospun fiber mats showed compatibility toward adipose derived stem cells, further confirming their potential use as wound dressing materials.

  3. 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

  4. 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.

  5. Evaluation of polyacrylonitrile electrospun nano-fibrous mats as leukocyte removal filter media.

    PubMed

    Pourbaghi, Raha; Zarrebini, Mohammad; Semnani, Dariush; Pourazar, Abbasali; Akbari, Nahid; Shamsfar, Reihaneh

    2017-09-13

    Removal of leukocytes from blood products is the most effective means for elimination of undesirable side effects and prevention of possible reactions in recipients. Micro-fibrous mats are currently used for removal of leukocytes from blood. In this study, samples of electrospun nano-fibrous mats were produced. The performance of the produced electrospun nano-fibrous mats as means of leukocytes removal from fresh whole blood was both evaluated and compared with that of commercially available micro-fibrous mats. In order to produce the samples, polyacrylonitrile (PAN) nano-fibrous mats were made under different electrospinning conditions. Mean fiber diameter, pore characterization and surface roughness of the PAN nano-fibrous mats were determined using image processing technique. In order to evaluate the surface tension of the fabricated mats, water contact angle was measured. The leukocyte removal performance, erythrocytes recovery percent and hemolysis rate of the nano-fibrous mats were compared. The effectiveness of nano-fibrous mats in removing leukocyte was established using both scanning electron microscope and optical microscope. Results showed that for given weight, the fabricated nano-fibrous mats were not only more efficient but also more cost-effective than their commercial counterparts. Results confirmed that changes in mean fiber diameter, the number of layer and weight of each layer in the absence of any chemical reaction or physical surface modification, the fabricated nano-fibrous mats were able to remove 5-log of leukocytes. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 Wiley Periodicals, Inc.

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

    PubMed

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

    2017-03-10

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

  7. The role of cellulose nanocrystals incorporation route in waterborne polyurethane for preparation of electrospun nanocomposites mats.

    PubMed

    Santamaria-Echart, Arantzazu; Ugarte, Lorena; Gonzalez, Kizkitza; Martin, Loli; Irusta, Lourdes; Gonzalez, Alba; Corcuera, Maria Angeles; Eceiza, Arantxa

    2017-06-15

    Electrospinning offers the possibility of obtaining fibers mats from polymer solutions. The use of environmentally-friendly waterborne polyurethane (WBPU) allows obtaining electrospun polyurethane mats in water medium. Furthermore, the incorporation of water dispersible nanoentities, like renewable cellulose nanocrystals (CNC), is facilitated. Therefore, in this work, a WBPU was synthesized and CNC were isolated for preparing WBPU-CNC dispersions nanocomposites with 1 and 3wt% of CNC following both the classical mixing by sonication, and the innovative in-situ route. The dispersions were used for obtaining electrospun mats assisted by poly(ethylene oxide) (PEO) as polymer template. Moreover, the extraction of PEO with water resulted in continuous WBPU-CNC mats, showing different properties respect to WBPU-CNC mats containing PEO. The effective addition of CNC led to more defined cylindrical morphologies and the two alternative incorporation routes induced to different CNC dispositions in the matrix, which modified fibers diameters, and thus, mats final properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    USDA-ARS?s Scientific Manuscript database

    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 ...

  9. 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Electrospun ultra-fine cellulose acetate fibrous mats containing tannic acid-Fe(3+) complexes.

    PubMed

    Yang, Weiqiao; Sousa, Ana M M; Fan, Xuetong; Jin, Tony; Li, Xihong; Tomasula, Peggy M; Liu, LinShu

    2017-02-10

    Cellulose acetate (CA) fibrous mats with improved mechanical and antioxidant properties were produced by a simple, scalable and cost-effective electrospinning method. Fibers loaded with small amounts of TA-Fe(3+) complexes showed an increase in tensile strength of ∼117% when compared to that of neat CA and were more resistant than those loaded with TA alone. The water uptake of the fibers increased upon TA or TA-Fe(3+) incorporation while their thermal behavior was only slightly affected. Fibrous mats loaded with TA-Fe(3+) showed comparable antioxidant activity with that of CA/TA mats, and a much slower TA release. These results suggest that TA-Fe(3+) complexes can be incorporated into electrospun CA fibers to improve their mechanical properties and antioxidant activity which may be of interest for the development of active packaging that can extend the shelf life of perishable foods.

  11. 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.

  12. 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

  13. Nanomechanics of electrospun phospholipid fiber

    NASA Astrophysics Data System (ADS)

    Mendes, Ana C.; Nikogeorgos, Nikolaos; Lee, Seunghwan; Chronakis, Ioannis S.

    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.

  14. 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.

  15. Stiffness of compressed fiber mats

    NASA Astrophysics Data System (ADS)

    Åström, J. A.; Mäkinen, J. P.; Hirvonen, H.; Timonen, J.

    2000-11-01

    We investigate, using an analytical and a numerical model, the in-plane stiffness of fiber mats. A mat is modeled by randomly depositing thin linear-elastic fibers on top of each other under the influence of an external pressure. The external pressure has the effect of bending the fibers over each other. The fibers are assumed rigidly bonded at contacts. For a low external pressure the stiffness of the mat deviates from that of its two-dimensional projection only by a geometrical factor, and the effective Poisson contraction is close to zero. For higher pressures, stiffness is governed by two competing effects and a maximum appears in the stiffness. The effective Poisson ratio is clearly negative in this range. An approximative analytical description is developed for the stiffness of mats formed under low external pressure. The stiffness is given as a function of only a few parameters: the degree of bonding, the dimensions of the fibers, the elastic constants of the fiber material, and the density of fibers.

  16. 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.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  18. Electrospun Fibers of Cyclodextrins and Poly(cyclodextrins).

    PubMed

    Costoya, Alejandro; Concheiro, Angel; Alvarez-Lorenzo, Carmen

    2017-02-03

    Cyclodextrins (CDs) can endow electrospun fibers with outstanding performance characteristics that rely on their ability to form inclusion complexes. The inclusion complexes can be blended with electrospinnable polymers or used themselves as main components of electrospun nanofibers. In general, the presence of CDs promotes drug release in aqueous media, but they may also play other roles such as protection of the drug against adverse agents during and after electrospinning, and retention of volatile fragrances or therapeutic agents to be slowly released to the environment. Moreover, fibers prepared with empty CDs appear particularly suitable for affinity separation. The interest for CD-containing nanofibers is exponentially increasing as the scope of applications is widening. The aim of this review is to provide an overview of the state-of-the-art on CD-containing electrospun mats. The information has been classified into three main sections: (i) fibers of mixtures of CDs and polymers, including polypseudorotaxanes and post-functionalization; (ii) fibers of polymer-free CDs; and (iii) fibers of CD-based polymers (namely, polycyclodextrins). Processing conditions and applications are analyzed, including possibilities of development of stimuli-responsive fibers.

  19. Controlled release of cefazolin sodium antibiotic drug from electrospun chitosan-polyethylene oxide nanofibrous Mats.

    PubMed

    Fazli, Yousef; Shariatinia, Zahra

    2017-02-01

    Antimicrobial electrospun chitosan-polyethylene oxide (CS-PEO) nanofibrous mats containing cefazolin, fumed silica (F. silica) and cefazolin-loaded fumed silica nanoparticles (NPs) were produced for biomedical applications. The FE-SEM images revealed that the F. silica and F. silica-cefazolin NPs had average diameters of 40±10 and 60±15nm, respectively. Also, the fibers diameters were approximately 160±30, 90±20 and 70±15nm for the pure CS-PEO, CS-PEO-1% F. silica and CS-PEO-1% F. silica-0.5% cefazolin nanofibrous mats, respectively indicating addition of F. silica and cefazolin loaded F. silica NPs to the CS-PEO mat led to decreasing the nanofiber diameter. Both of the CS-PEO mats containing 2.5% cefazolin and 1% F. silica-0.50% cefazolin showed 100% bactericidal activities against both S. aureus and E. coli bacteria. The cefazolin release from mats was sharply increased within first 24 and 6hours for the CS-PEO mats including 2.5% cefazolin and 1% F. silica-0.50% cefazolin but after that the drug was released very slowly. The improved hydrophilicity, higher tensile strength and sustained drug release for CS-PEO-1% F. silica-0.50% cefazolin suggested that it was the best nanocomposite tissue/device for biomedical applications among the mats CS-PEO-2.5% cefazolin and CS-PEO-1% F. silica. The wound healing ability of the CS-PEO-F. silica-cefazolin mat was evaluated on the wounded skins of the female Wistar rats and it was shown that the wounded skins of the rats were almost entirely healed after ten days using this mat as a wound dressing scaffold. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Wetting of Hydrophilic Electrospun Mats Produced by Blending SEBS with PEO-PPO-PEO Copolymers of Different Molecular Weight.

    PubMed

    Kurusu, Rafael S; Demarquette, Nicole R

    2016-02-23

    The interaction of electrospun mats with water is critical for many possible applications, and the water contact angle on the surface is the parameter usually measured to characterize wetting. Although useful for hydrophobic surfaces, this approach is limited for hydrophilic mats, where wicking also has to be considered. In this case, it is still unclear how the fiber surface chemical composition and morphology will affect the wetting behavior of electrospun mats. In this work, wetting was studied with different hydrophilic membranes produced by blending thermoplastic elastomer poly(styrene)-b-poly(ethylene-butylene)-b-poly(styrene) (SEBS) with amphiphilic poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) (PEO-PPO-PEO) molecules. Three different types of PEO-PPO-PEO, with different molar masses, PEO content, and physical form were used. The effect of these differences on the wetting behavior of the electrospun mats was evaluated by contact angle goniometry, wicking measurements, and different imaging techniques. X-ray photoelectron spectroscopy was used to characterize the surface chemical composition. The smaller molecules quickly saturated the surface at low concentrations, making the mats hydrophilic. The sheath of PEO-PPO-PEO also resulted in fast absorption of water, when comparing the saturated and nonsaturated surfaces. Longer PEO chain-ends seemed to hinder complete segregation and also led to a higher activation time when in contact with water. Liquid PEO-PPO-PEO was easily leached by water.

  1. Electrospun nano-fibre mats with antibacterial properties from quaternised chitosan and poly(vinyl alcohol).

    PubMed

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

    2006-09-04

    Nano-fibres containing quaternised chitosan (QCh) have been successfully prepared by electrospinning of QCh solutions mixed with poly(vinyl alcohol) (PVA). The average fibre diameter is in the range of 60-200 nm. UV irradiation of the composite electrospun nano-fibrous mats containing triethylene glycol diacrylate as cross-linking agent has resulted in stabilising of the nano-fibres against disintegration in water or water vapours. Microbiological screening has demonstrated the antibacterial activity of the photo-cross-linked electrospun mats against Staphylococcus aureus and Escherichia coli. The obtained nano-fibrous electrospun mats are promising for wound-healing applications.

  2. Functionalizing Electrospun Fibers with Biologically Relevant Macromolecules

    PubMed Central

    Casper, Cheryl L.; Yamaguchi, Nori; Kiick, Kristi L.; Rabolt, John F.

    2008-01-01

    The development of functionalized polymers that can elicit specific biological responses is of great interest in the biomedical community, as well as the development of methods to fabricate these biologically functionalized polymers. For example, the generation of fibrous matrices with biological properties and fiber diameters commensurate with those of the natural extracellular matrix (ECM) may permit the development of novel materials for use in wound healing or tissue engineering. The goal of this work is, therefore, to create a biologically active functionalized electrospun matrix to permit immobilization and long-term delivery of growth factors. In this work, poly(ethylene glycol) functionalized with low molecular weight heparin (PEG-LMWH) was fabricated into fibers for possible use in drug delivery, tissue engineering, or wound repair applications. Electrospinning was chosen to process the LMWH into fiber form due to the small fiber diameters and high degree of porosity that can be obtained relatively quickly and using small amounts of starting material. Both free LMWH and PEG-LMWH were investigated for their ability to be incorporated into electrospun fibers. Each of the samples were mixed with a carrier polymer consisting of either a 10 wt % poly(ethylene oxide) (PEO) or 45 wt % poly(lactide-co-glycolide) (PLGA). Field emission scanning electron microscopy (FESEM), energy-dispersive X-ray analysis (EDX), UV–vis spectroscopy, and multiphoton microscopy were used to characterize the electrospun matrices. The incorporation of heparin into the electrospun PEO and PLGA fibers did not affect the surface morphology or fiber diameters. The fibers produced had diameters ranging from approximately 100 to 400 nm. Toluidine blue assays of heparin suggest that it can be incorporated into an electrospun matrix at concentrations ranging from 3.5 to 85 μg per milligram of electrospun fibers. Multiphoton microscopy confirmed that incorporation of PEG-LMWH into the matrix

  3. Electrospun fibrous mats on lithographically micropatterned collectors to control cellular behaviors.

    PubMed

    Liu, Yaowen; Zhang, Lei; Li, Huinan; Yan, Shili; Yu, Junsheng; Weng, Jie; Li, Xiaohong

    2012-12-11

    Spatial arrangement of multiple cell types plays a critical role in maintaining the viability of cells and functionality of tissues. Micropatterning has been used to fabricate scaffolds to modulate cell distribution, growth, and functions for reconstructing the anisotropy in native tissues. In the current study, a glass substrate patterned with an electrically conductive circuit was prepared by lithography as a collector for electrospinning. Densely packed fibers were deposited on the top of silver strips and patterned fibrous mats were obtained with distinct ridge and groove areas. Orthogonal alignment was shown for fibers in the ridge and groove areas, and the pattern feature and fiber alignment were well maintained in the ridge during incubation of cells with patterned fibrous mats. Sequential confocal laser scanning from the top of cell-loaded fibrous mats indicated that a larger number of cells were spread in the ridge than that in the groove areas, and cells penetrated into the fibrous mats in the ridge. Microscopic observation and immunofluorescent staining indicated that cells and collagen deposition appeared to have distinct patterns on the fibrous scaffold and aligned along the directionality of fibers with an elongated morphology. It is concluded that lithography can provide the design flexibility of collectors with micrometer-scale precision patterning, and cells can be confined to precise locations, sizes, and shapes by the use of micropatterned fibrous scaffolds without any adverse effect on the cell viability and function. The results suggest the potential of patterned electrospun fibrous mats to construct complex tissues of well organized multiple cell types and with spatially distributed extracellular matrices.

  4. 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.

  5. Significantly reinforced composite fibers electrospun from silk fibroin/carbon nanotube aqueous solutions.

    PubMed

    Pan, Hui; Zhang, Yaopeng; Hang, Yichun; Shao, Huili; Hu, Xuechao; Xu, Yuemin; Feng, Chao

    2012-09-10

    Microcomposite fibers of regenerated silk fibroin (RSF) and multiwalled carbon nanotubes (MWNTs) were successfully prepared by an electrospinning process from aqueous solutions. A quiescent blended solution and a three-dimensional Raman image of the composite fibers showed that functionalized MWNTs (F-MWNTs) were well dispersed in the solutions and the RSF fibers, respectively. Raman spectra and wide-angle X-ray diffraction (WAXD) patterns of RSF/F-MWNT electrospun fibers indicated that the composite fibers had higher β-sheet content and crystallinity than the pure RSF electrospun fibers, respectively. The mechanical properties of the RSF electrospun fibers were improved drastically by incorporating F-MWNTs. Compared with the pure RSF electrospun fibers, the composite fibers with 1.0 wt % F-MWNTs exhibited a 2.8-fold increase in breaking strength, a 4.4-fold increase in Young's modulus, and a 2.1-fold increase in breaking energy. Cytotoxicity test preliminarily demonstrated that the electrospun fiber mats have good biocompatibility for tissue engineering scaffolds.

  6. Fabrication, Polarization of Electrospun Polyvinylidene Fluoride Electret Fibers and Effect on Capturing Nanoscale Solid Aerosols.

    PubMed

    Lolla, Dinesh; Lolla, Manideep; Abutaleb, Ahmed; Shin, Hyeon U; Reneker, Darrell H; Chase, George G

    2016-08-09

    Electrospun polyvinylidene fluoride (PVDF) fiber mats with average fiber diameters (≈200 nm, ≈2000 nm) were fabricated by controlled electrospinning conditions. These fiber mats were polarized using a custom-made device to enhance the formation of the electret β-phase ferroelectric property of the fibers by simultaneous uniaxial stretching of the fiber mat and heating the mat to the Curie temperature of the PVDF polymer in a strong electric field of 2.5 kV/cm. Scanning electron microscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis, differential scanning calorimetry and Brunauer-Emmett-Teller (BET) surface area analyses were performed to characterize both the internal and external morphologies of the fiber mat samples to study polarization-associated changes. MATLAB simulations revealed the changes in the paths of the electric fields and the magnetic flux inside the polarization field with inclusion of the ferroelectric fiber mats. Both polarized and unpolarized fiber mats were challenged as filters against NaCl particles with average particle diameters of about 150 nm using a TSI 8130 to study capture efficiencies and relative pressure drops. Twelve filter experiments were conducted on each sample at one month time intervals between experiments to evaluate the reduction of the polarization enhancement over time. The results showed negligible polarization loss for the 200-nm fiber sample. The polarized mats had the highest filter efficiencies and lowest pressure drops.

  7. Fabrication, Polarization of Electrospun Polyvinylidene Fluoride Electret Fibers and Effect on Capturing Nanoscale Solid Aerosols †

    PubMed Central

    Lolla, Dinesh; Lolla, Manideep; Abutaleb, Ahmed; Shin, Hyeon U.; Reneker, Darrell H.; Chase, George G.

    2016-01-01

    Electrospun polyvinylidene fluoride (PVDF) fiber mats with average fiber diameters (≈200 nm, ≈2000 nm) were fabricated by controlled electrospinning conditions. These fiber mats were polarized using a custom-made device to enhance the formation of the electret β-phase ferroelectric property of the fibers by simultaneous uniaxial stretching of the fiber mat and heating the mat to the Curie temperature of the PVDF polymer in a strong electric field of 2.5 kV/cm. Scanning electron microscopy, Fourier transform infrared spectroscopy, thermal gravimetric analysis, differential scanning calorimetry and Brunauer-Emmett-Teller (BET) surface area analyses were performed to characterize both the internal and external morphologies of the fiber mat samples to study polarization-associated changes. MATLAB simulations revealed the changes in the paths of the electric fields and the magnetic flux inside the polarization field with inclusion of the ferroelectric fiber mats. Both polarized and unpolarized fiber mats were challenged as filters against NaCl particles with average particle diameters of about 150 nm using a TSI 8130 to study capture efficiencies and relative pressure drops. Twelve filter experiments were conducted on each sample at one month time intervals between experiments to evaluate the reduction of the polarization enhancement over time. The results showed negligible polarization loss for the 200-nm fiber sample. The polarized mats had the highest filter efficiencies and lowest pressure drops. PMID:28773798

  8. Coaxially electrospun PVDF-Teflon AF and Teflon AF-PVDF core-sheath nanofiber mats with superhydrophobic properties.

    PubMed

    Muthiah, Palanikkumaran; Hsu, Shu-Hau; Sigmund, Wolfgang

    2010-08-03

    This work reports the coaxial electrospinning of poly(vinylidene fluoride) (PVDF)-Teflon amorphous fluoropolymer (AF) and Teflon AF-PVDF core-sheath nanofiber mats yielding superhydrophobic properties. The coaxial electrospinning configuration allows for the electrospinning of Teflon AF, a nonelectrospinnable polymer, with the help of an electrospinnable PVDF polymer. PVDF-Teflon AF and Teflon AF-PVDF core-sheath fibers have been found to a have mean fiber diameter ranging from 400 nm to less than 100 nm. TEM micrographs exhibit a typical core-sheath fiber structure for these fibers, where the sheath fiber coats the core fiber almost thoroughly. Water contact angle measurements by sessile drop method on these core-sheath nanofiber mats exhibited superhydrophobic characteristics with contact angles close to or higher than 150 degrees. Surprisingly, PVDF-Teflon AF and Teflon AF-PVDF nanofiber mat surface properties were dominated by the fiber dimensions and less influenced by the type of sheath polymer. This suggests that highly fluorinated polymer Teflon AF does not advance the hydrophobicity beyond what surface physics and slightly fluorinated polymer PVDF can achieve. It is concluded that PVDF-Teflon AF and Teflon AF-PVDF core-sheath electrospun nanofiber mats may be used in lithium (Li)-air batteries.

  9. Electrospun cellulose acetate-garnet nanocomposite magnetic fibers for bioseparations.

    PubMed

    Munaweera, Imalka; Aliev, Ali; Balkus, Kenneth J

    2014-01-08

    Cellulose acetate fibers with magnetic properties have recently attracted much attention because of their potential novel applications in biomedicine such as for cell and protein separations, magnetic resonance imaging contrast agents, and magnetic filters. In this work, as synthesized yttrium iron garnet and gadolinium substituted yttrium iron garnet nanoparticles have been used to generate magnetic filter paper. Garnet nanoparticles dispersed in cellulose acetate polymer solutions were electrospun as free-standing nonwoven fiber mats as well as on cellulose filter paper substrates resulting in magnetic filter papers. The magnetic fibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), and superconducting quantum interference device (SQUID) magnetic property measurements. The resulting magnetic polymer nanocomposites can be easily picked up by an external magnet from a liquid medium. Fluorescein isothiocyanate (FITC) labeled bovine serum albumin (BSA) was separated from solution by using the magnetic filter paper.

  10. Morphology and structure of electrospun mats from regenerated silk fibroin aqueous solutions with adjusting pH.

    PubMed

    Zhu, Jingxin; Shao, Huili; Hu, Xuechao

    2007-10-01

    In this paper, regenerated silk fibroin (SF) aqueous solutions were adjusted to a pH of 6.9 by mimicing the condition in the posterior division of silkworm's gland and rheological behavior of solutions was investigated. The electrospinning technique was used to prepare fibers, and non-woven mats of regenerated B. mori silk fibroin were successfully obtained. The effects of electrospinning parameters on the morphology and diameter of regenerated silk fibers were investigated by orthogonal design. Statistical analysis showed that voltage, the concentration of regenerated SF solutions and the distance between tip and collection plate were the most dominant parameters to fiber morphology, diameter and diameter distribution, respectively. An optimal electrospinning condition was obtained in producing uniform cylindrical fibers with an average diameter of 1300nm. It was as follows: the concentration 30%, voltage 40kV, distance 20cm. The structure of electrospun mats was characterized by Raman spectroscopy (RS), wide-angle X-ray diffraction (WAXD) and modulated differential scanning calorimetry (MDSC). It was found that electrospun mats were predominantly random coil/silk I structure, and the transition to silk II (beta-sheet) rich structure should be further explored.

  11. Electrospun Nanofiber Scaffolds with Gradations in Fiber Organization

    PubMed Central

    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

  12. 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.

  13. The influence of specimen thickness and alignment on the material and failure properties of electrospun polycaprolactone nanofiber mats.

    PubMed

    Mubyana, Kuwabo; Koppes, Ryan A; Lee, Kristen L; Cooper, James A; Corr, David T

    2016-11-01

    Electrospinning is a versatile fabrication technique that has been recently expanded to create nanofibrous structures that mimic ECM topography. Like many materials, electrospun constructs are typically characterized on a smaller scale, and scaled up for various applications. This established practice is based on the assumption that material properties, such as toughness, failure stress and strain, are intrinsic to the material, and thus will not be influenced by specimen geometry. However, we hypothesized that the material and failure properties of electrospun nanofiber mats vary with specimen thickness. To test this, we mechanically characterized polycaprolactone (PCL) nanofiber mats of three different thicknesses in response to constant rate elongation to failure. To identify if any observed thickness-dependence could be attributed to fiber alignment, such as the effects of fiber reorientation during elongation, these tests were performed in mats with either random or aligned nanofiber orientation. Contrary to our hypothesis, the failure strain was conserved across the different thicknesses, indicating similar maximal elongation for specimens of different thickness. However, in both the aligned and randomly oriented groups, the ultimate tensile stress, short-range modulus, yield modulus, and toughness all decreased with increasing mat thickness, thereby indicating that these are not intrinsic material properties. These findings have important implications in engineered scaffolds for fibrous and soft tissue applications (e.g., tendon, ligament, muscle, and skin), where such oversights could result in unwanted laxity or reduced resistance to failure. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2794-2800, 2016.

  14. Electrospun mats from styrene/maleic anhydride copolymers: modification with amines and assessment of antimicrobial activity.

    PubMed

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

    2010-08-11

    New antimicrobial microfibrous electrospun mats from styrene/maleic anhydride copolymers were prepared. Two approaches were applied: (i) grafting of poly(propylene glycol) monoamine (Jeffamine® M-600) on the mats followed by formation of complex with iodine; (ii) modification of the mats with amines of 8-hydroxyquinoline or biguanide type with antimicrobial activity. Microbiological screening against S. aureus, E. coli and C. albicans revealed that both the formation of complex with iodine and the covalent attachment of 5-amino-8-hydroxyquinoline or of chlorhexidine impart high antimicrobial activity to the mats. In addition, S. aureus bacteria did not adhere to modified mats.

  15. 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.

  16. 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.

  17. An investigation of electrospun Henna leaves extract-loaded chitosan based nanofibrous mats for skin tissue engineering.

    PubMed

    Yousefi, Iman; Pakravan, Mehdi; Rahimi, Hoda; Bahador, Abbas; Farshadzadeh, Zahra; Haririan, Ismael

    2017-06-01

    Wound healing characteristics of some plant extracts have been well known for many years, and they have been utilized for such applications in traditional way. Recently electrospun nanofibrous mats showed promising properties for tissue engineering and especially for skin repair. It is expected that incorporation of plant extracts into such structures could provide higher performance and synergistic effect for biomedical and wound healing applications. The final purpose of this study is to fabricate chitosan based nanofiber mats loaded with a traditional plant extract of Lawsonia inermis (Henna) leaves to enhance the antibacterial efficacy and wound healing of the precursor nanofibers. The morphology, structure, mechanical properties and swelling and weight loss degree of the electrospun nanofibers have been investigated in this study. Antibacterial activity, cell biocompatibility evaluations and in vivo wound healing activity of the abovementioned mats were also studied. The FESEM images of Henna leaves extract-loaded nanofibers proved that homogeneous, smooth and defect free nanofibers of 64-87nm in diameter have been prepared. Presence of Henna extract in the electrospun fibers was approved by Fourier Transform Infrared spectroscopy. Incorporation of Henna extract into the nanofiber mats exhibited significant synergistic antibacterial activity against bacterial cells. It was well supported by the results of cell viability and proliferation of human foreskin fibroblast cells on the prepared scaffolds. Therefore, the results of this work showed that Henna leaves extract incorporated chitosan nonwoven mats have a great potential to be used as the biodegradable, biobased and antibacterial wound healing dressings. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Electrospun fibrous mats with conjugated tetraphenylethylene and mannose for sensitive turn-on fluorescent sensing of Escherichia coli.

    PubMed

    Zhao, Long; Chen, Yufei; Yuan, Jiang; Chen, Maohua; Zhang, Hong; Li, Xiaohong

    2015-03-11

    A rapid and sensitive detection of microbes in water and biological fluids is a key requirement in water and food safety, environmental monitoring, and clinical diagnosis and treatment. In the current study, electrospun polystyrene-co-maleic anhydride (PSMA) fibers with conjugated mannose and tetraphenylethylene (TPE) were developed for Escherichia coli (E. coli) detection, taking advantage of the high grafting capabilities of ultrafine fibers and the highly porous structure of the fibrous mat to entrap bacterial cells. The specific binding between mannose grafts on PSMA fibers and FimH proteins from the fimbriae of E. coli led to an efficient "turn-on" profile of TPE due to the aggregation-induced emission (AIE) effect. Poly(ethylene glycol) diamine was used as hydrophilic tethers to increase the conformational mobility of mannose grafts, indicating a more sensitive change in the fluorescence intensity against bacteria concentrations, a lower fluorescence background of fibers without bacteria incubation, and a sufficient space for bacteria binding, compared with the use of hexamethylenediamine or poly(ethylene imine) as spacers for mannose grafting. The addition of bovine serum albumin, glucose, or both of them into bacteria suspensions showed no significant changes in the fluorescence intensity of fibrous mats, indicating the anti-interference capability against these proteins and saccharides. An equation was drafted of the fluorescence intensities of fibrous mats against E. coli concentrations ranging from 10(2) to 10(5) CFU/mL. The test strip format was established on mannose-conjugated PSMA fibers after exposure to E. coli of different concentrations, providing a potential tool with a visual sensitivity of bacteria concentrations as low as 10(2) CFU/mL in a matter of minutes. This strategy may offer a capacity to be expanded to exploit electrospun fibrous mats and other carbohydrate-cell interactions for bioanalysis and biosensing of pathogenic bacteria.

  19. 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

    2016-06-07

    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.

  20. Flat, Branched and Split Electrospun Fibers

    NASA Astrophysics Data System (ADS)

    Koombhongse, Sureeporn; Reneker, Darrell H.

    2001-03-01

    The electrospinning process uses electrical force to overcome the force from surface tension. As the electric field increases, the surface of a droplet becomes nearly conical and a charged jet flows from the vertex. The charged jet moves along a straight line for some distance and then begins a spiraling path, which is triggered by a bending instability.[1] The charged jet solidifies as it dries and electrospun nanofibers are collected. The electrospinning process normally produces cylindrical fibers, but sometimes the fibers are flat, branched or split. Flat fibers were electrospun from polystyrene (PS) and poly(2-hydroxyethyl methacrylate) (HEMA) solution. Flat fibers were formed by the collapse of a tube. Branched fibers of HEMA, PS and poly(vinylidene fluoride) were observed. The thinner branch was usually perpendicular to the axis of the primary jet. Branched fibers are formed by a smaller secondary jet ejected from the surface of the primary jet. The charged jet can split apart into two smaller jets to reduce the charge per unit surface area. Split fibers of HEMA, in which two smaller jets run parallel to the axis of the primary jet were observed. 1. D.H. Reneker, A.L. Yarin, H. Fong, and S. Koombhongse, J. Appl. Phys. 87, 4531 (2000).

  1. Electrospun cross linked rosin fibers

    NASA Astrophysics Data System (ADS)

    Baek, Woo-il; Nirmala, R.; Barakat, Nasser A. M.; El-Newehy, Mohamed H.; Al-Deyab, Salem S.; Kim, Hak Yong

    2011-12-01

    In this study, we describe the first reported preparation of rosin in fiber form through use of an electrospinning technique utilizing various solvent systems. The polymer concentration of the formed fiber was studied by using various solvents such as chloroform, ethanol, N-N dimethylformamide (DMF), tetrahydrofuran (THF), acetone, and methylene chloride (MC). An electrospray of the solution resulted in the beaded form of the rosin. By varying the polymer concentration with MC, we were then able to obtain uniform fibers. However, the fibers exhibited large diameter. We believe that it is possible to reduce the diameter of the rosin fibers through appropriate selection of electrospinning parameters. In addition, the morphological transitions from beads, to beaded fiber, to fiber were studied at different polymer concentrations. We propose a possible physical cross linking mechanism for the formation of rosin fibers during the electrospinning process. Our results demonstrate the feasibility of producing fiber nanostructures of rosin by using an electrospinning technique.

  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

    2015-03-06

    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. Release of metronidazole from electrospun poly(L-lactide-co-D/L-lactide) fibers for local periodontitis treatment.

    PubMed

    Reise, Markus; Wyrwa, Ralf; Müller, Ulrike; Zylinski, Matthias; Völpel, Andrea; Schnabelrauch, Matthias; Berg, Albrecht; Jandt, Klaus D; Watts, David C; Sigusch, Bernd W

    2012-02-01

    We aimed to achieve detailed biomaterials characterization of a drug delivery system for local periodontitis treatment based on electrospun metronidazole-loaded resorbable polylactide (PLA) fibers. PLA fibers loaded with 0.1-40% (w/w) MNA were electrospun and were characterized by SEM and DSC. HPLC techniques were used to analyze the release profiles of metronidazole (MNA) from these fibers. The antibacterial efficacy was determined by measuring inhibition zones of drug-containing aliquots from the same electrospun fiber mats in an agar diffusion test. Three pathogenic periodontal bacterial strains: Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis were studied. Cytotoxicity testing was performed with human gingival fibroblasts by: (i) counting viable cells via live/dead staining methods and (ii) by exposing cells directly onto the surface of MNA-loaded fibers. MNA concentration influenced fiber diameters and thus w/w surface areas: diameter being minimal and area maximal at 20% MNA. HPLC showed that these 20% MNA fibers had the fastest initial MNA release. From the third day, MNA release was slower and nearly linear with time. All fiber mats released 32-48% of their total drug content within the first 7 days. Aliquots of media taken from the fiber mats inhibited the growth of all three bacterial strains. MNA released up to the 28th day from fiber mats containing 40% MNA significantly decreased the viability of F. nucleatum and P. gingivalis and up to the 2nd day also for the resistant A. actinomycetemcomitans. All of the investigated fibers and aliquots showed excellent cytocompatibility. This study shows that MNA-loaded electrospun fiber mats represent an interesting class of resorbable drug delivery systems. Sustained drug release properties and cytocompatibility suggest their potential clinical applicability for the treatment of periodontal diseases. Copyright © 2011 Academy of Dental Materials. Published by Elsevier

  5. Luminescent composite polymer fibers: in situ synthesis of silver nanoclusters in electrospun polymer fibers and application.

    PubMed

    Gao, Wenran; Wang, Xumei; Xu, Weiqing; Xu, Shuping

    2014-09-01

    The purpose of this study is to prepare multifunctional polymer fibers. We report a simple and controllable method for in situ synthesis of Ag nanoclusters (NCs) in electrospun polymer fibers via a photochemical reaction. The prepared composite polymer fibers emit pink luminescence and the luminescence property can be optimized by pH and Ag(I) precursor concentration. The as-prepared Ag NCs in electrospun polymer fibers were mainly Ag2-5 with a quantum yield of 6.81% and a lifetime of 2.29 ns. The in situ growth of Ag NCs avoids excessive surface modifications which may cause the aggregation of Ag NCs in many ex situ assembly methods. The combination of Ag NCs with polymer fibers greatly improves the stability of Ag NCs and broadens their applications. The storage of Ag NCs becomes facilitative due to the formation of bulky mat. Furthermore, these luminescence composite polymer fibers show strong antibacterial activity against Staphylococcus aureus (S. aureus).

  6. 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.

  7. 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.

  8. 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

  9. Preparation and Properties of Electrospun Poly (Vinyl Pyrrolidone)/Cellulose Nanocrystal/Silver Nanoparticle Composite Fibers

    PubMed Central

    Huang, Siwei; Zhou, Ling; Li, Mei-Chun; Wu, Qinglin; Kojima, Yoichi; Zhou, Dingguo

    2016-01-01

    Poly (vinyl pyrrolidone) (PVP)/cellulose nanocrystal (CNC)/silver nanoparticle composite fibers were prepared via electrospinning using N,N′-dimethylformamide (DMF) as a solvent. Rheology, morphology, thermal properties, mechanical properties, and antimicrobial activity of nanocomposites were characterized as a function of material composition. The PVP/CNC/Ag electrospun suspensions exhibited higher conductivity and better rheological properties compared with those of the pure PVP solution. The average diameter of the PVP electrospun fibers decreased with the increase in the amount of CNCs and Ag nanoparticles. Thermal stability of electrospun composite fibers was decreased with the addition of CNCs. The CNCs help increase the composite tensile strength, while the elongation at break decreased. The composite fibers included Ag nanoparticles showed improved antimicrobial activity against both the Gram-negative bacterium Escherichia coli (E. coli) and the Gram-positive bacterium Staphylococcus aureus (S. aureus). The enhanced strength and antimicrobial performances of PVP/CNC/Ag electrospun composite fibers make the mat material an attractive candidate for application in the biomedical field. PMID:28773644

  10. 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. Copyright © 2012 Wiley Periodicals, Inc.

  11. Highly reproducible thermocontrolled electrospun fiber based organic photovoltaic devices.

    PubMed

    Kim, Taehoon; Yang, Seung Jae; Sung, Sae Jin; Kim, Yern Seung; Chang, Mi Se; Jung, Haesol; Park, Chong Rae

    2015-03-04

    In this work, we examined the reasons underlying the humidity-induced morphological changes of electrospun fibers and suggest a method of controlling the electrospun fiber morphology under high humidity conditions. We fabricated OPV devices composed of electrospun fibers, and the performance of the OPV devices depends significantly on the fiber morphology. The evaporation rate of a solvent at various relative humidity was measured to investigate the effects of the relative humidity during electrospinning process. The beaded nanofiber morphology of electrospun fibers was originated due to slow solvent evaporation rate under high humidity conditions. To increase the evaporation rate under high humidity conditions, warm air was applied to the electrospinning system. The beads that would have formed on the electrospun fibers were completely avoided, and the power conversion efficiencies of OPV devices fabricated under high humidity conditions could be restored. These results highlight the simplicity and effectiveness of the proposed method for improving the reproducibility of electrospun nanofibers and performances of devices consisting of the electrospun nanofibers, regardless of the relative humidity.

  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

    2016-06-05

    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.

  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.

  14. Electro-Responsive Behaviour Multi-Wall Nanotubes/Gelatin Composites and Cross-Linked Gelatin Electrospun Mats

    DTIC Science & Technology

    2008-02-11

    1 Final Report on Electro-responsive behaviour multi-wall nanotubes /gelatin composites and cross-linked gelatin electrospun mats...12-10-2007 4. TITLE AND SUBTITLE Electro-responsive behaviour multi-wall nanotubes /gelatin composites and cross-linked gelatin electrospun mats...such as polymer gels 2-3, conducting polymers 4-5, carbon nanotube composites 6-8, and dielectric elastomers 9 are some of the most promising materials

  15. 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.

  16. New crosslinkers for electrospun chitosan fibre mats. Part II: mechanical properties

    PubMed Central

    Donius, Amalie E.; Kiechel, Marjorie A.; Schauer, Caroline L.; Wegst, Ulrike G. K.

    2013-01-01

    Few studies exist on the mechanical performance of crosslinked electrospun chitosan (CS) fibre mats. In this study, we show that the mat structure and mechanical performance depend on the different crosslinking agents genipin, epichlorohydrin (ECH), and hexamethylene-1,6-diaminocarboxysulphonate (HDACS), as well as the post-electrospinning heat and base activation treatments. The mat structure was imaged by field emission scanning electron microscopy and the mechanical performance was tested in tension. The elastic modulus, tensile strength, strain at failure and work to failure were found to range from 52 to 592 MPa, 2 to 30 MPa, 2 to 31 per cent and 0.041 to 3.26 MJ m−3, respectively. In general, neat CS mats were found to be the stiffest and the strongest, though least ductile, while CS–ECH mats were the least stiff, weakest, but the most ductile, and CS–HDACS fibre mats exhibited intermediary mechanical properties. The mechanical performance of the mats is shown to reflect differences in the fibre diameter, number of fibre–fibre contacts formed within the mat, as well as varying intermolecular bonding and moisture content. The findings reported here complement the chemical properties of the mats, described in part I of this study. PMID:23349435

  17. New crosslinkers for electrospun chitosan fibre mats. Part II: mechanical properties.

    PubMed

    Donius, Amalie E; Kiechel, Marjorie A; Schauer, Caroline L; Wegst, Ulrike G K

    2013-04-06

    Few studies exist on the mechanical performance of crosslinked electrospun chitosan (CS) fibre mats. In this study, we show that the mat structure and mechanical performance depend on the different crosslinking agents genipin, epichlorohydrin (ECH), and hexamethylene-1,6-diaminocarboxysulphonate (HDACS), as well as the post-electrospinning heat and base activation treatments. The mat structure was imaged by field emission scanning electron microscopy and the mechanical performance was tested in tension. The elastic modulus, tensile strength, strain at failure and work to failure were found to range from 52 to 592 MPa, 2 to 30 MPa, 2 to 31 per cent and 0.041 to 3.26 MJ m(-3), respectively. In general, neat CS mats were found to be the stiffest and the strongest, though least ductile, while CS-ECH mats were the least stiff, weakest, but the most ductile, and CS-HDACS fibre mats exhibited intermediary mechanical properties. The mechanical performance of the mats is shown to reflect differences in the fibre diameter, number of fibre-fibre contacts formed within the mat, as well as varying intermolecular bonding and moisture content. The findings reported here complement the chemical properties of the mats, described in part I of this study.

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

    PubMed

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

    2012-10-07

    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 (T(600)) 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.

  19. 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

  20. 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. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Bacterial polyhydroxybutyrate for electrospun fiber production.

    PubMed

    Acevedo, Francisca; Villegas, Pamela; Urtuvia, Viviana; Hermosilla, Jeyson; Navia, Rodrigo; Seeger, Michael

    2017-08-16

    Nano- and microfibers obtained by electrospinning have attracted great attention due to its versatility and potential for applications in diverse technological fields. Polyhydroxyalkanoates (PHAs) are biopolymers synthesized by microorganisms such as the bacterium Burkholderia xenovorans LB400. In particular, LB400 cells are capable to synthesize poly(3-hydroxybutyrate) (PHB) from glucose. The aim of this study was to produce and characterize electrospun fibers obtained from bacterial PHBs. Bacterial strain LB400 was grown in M9 minimal medium using xylose and mannitol (10gL(-1)) as the sole carbon sources and NH4Cl (1gL(-1)) as the sole nitrogen source. Biopolymer-based films obtained were used to produce fibers by electrospinning. Diameter and morphology of the microfibers were analyzed by scanning electron microscopy (SEM) and their thermogravimetric properties were investigated. Bead-free fibers using both PHBs were obtained with diameters of less than 3μm. The surface morphology of the microfibers based on PHBs obtained from both carbon sources was different, even though their thermogravimetric properties are similar. The results indicate that the carbon source may determine the fiber structure and properties. Further studies should be performed to analyze the physicochemical and mechanical properties of these PHB-based microfibers, which may open up novel applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. 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.

  3. 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. Copyright © 2011 Elsevier B.V. All rights reserved.

  4. Halloysite nanotube-based electrospun ceramic nanofibre mat: a novel support for zeolite membranes

    PubMed Central

    Chen, Zhuwen; Zeng, Jiaying; Lv, Dong; Gao, Jinqiang; Zhang, Jian; Bai, Shan; Li, Ruili; Wu, Jingshen

    2016-01-01

    Some key parameters of supports such as porosity, pore shape and size are of great importance for fabrication and performance of zeolite membranes. In this study, we fabricated millimetre-thick, self-standing electrospun ceramic nanofibre mats and employed them as a novel support for zeolite membranes. The nanofibre mats were prepared by electrospinning a halloysite nanotubes/polyvinyl pyrrolidone composite followed by a programmed sintering process. The interwoven nanofibre mats possess up to 80% porosity, narrow pore size distribution, low pore tortuosity and highly interconnected pore structure. Compared with the commercial α-Al2O3 supports prepared by powder compaction and sintering, the halloysite nanotube-based mats (HNMs) show higher flux, better adsorption of zeolite seeds, adhesion of zeolite membranes and lower Al leaching. Four types of zeolite membranes supported on HNMs have been successfully synthesized with either in situ crystallization or a secondary growth method, demonstrating good universality of HNMs for supporting zeolite membranes. PMID:28083098

  5. Halloysite nanotube-based electrospun ceramic nanofibre mat: a novel support for zeolite membranes

    NASA Astrophysics Data System (ADS)

    Chen, Zhuwen; Zeng, Jiaying; Lv, Dong; Gao, Jinqiang; Zhang, Jian; Bai, Shan; Li, Ruili; Hong, Mei; Wu, Jingshen

    2016-12-01

    Some key parameters of supports such as porosity, pore shape and size are of great importance for fabrication and performance of zeolite membranes. In this study, we fabricated millimetre-thick, self-standing electrospun ceramic nanofibre mats and employed them as a novel support for zeolite membranes. The nanofibre mats were prepared by electrospinning a halloysite nanotubes/polyvinyl pyrrolidone composite followed by a programmed sintering process. The interwoven nanofibre mats possess up to 80% porosity, narrow pore size distribution, low pore tortuosity and highly interconnected pore structure. Compared with the commercial α-Al2O3 supports prepared by powder compaction and sintering, the halloysite nanotube-based mats (HNMs) show higher flux, better adsorption of zeolite seeds, adhesion of zeolite membranes and lower Al leaching. Four types of zeolite membranes supported on HNMs have been successfully synthesized with either in situ crystallization or a secondary growth method, demonstrating good universality of HNMs for supporting zeolite membranes.

  6. Halloysite nanotube-based electrospun ceramic nanofibre mat: a novel support for zeolite membranes.

    PubMed

    Chen, Zhuwen; Zeng, Jiaying; Lv, Dong; Gao, Jinqiang; Zhang, Jian; Bai, Shan; Li, Ruili; Hong, Mei; Wu, Jingshen

    2016-12-01

    Some key parameters of supports such as porosity, pore shape and size are of great importance for fabrication and performance of zeolite membranes. In this study, we fabricated millimetre-thick, self-standing electrospun ceramic nanofibre mats and employed them as a novel support for zeolite membranes. The nanofibre mats were prepared by electrospinning a halloysite nanotubes/polyvinyl pyrrolidone composite followed by a programmed sintering process. The interwoven nanofibre mats possess up to 80% porosity, narrow pore size distribution, low pore tortuosity and highly interconnected pore structure. Compared with the commercial α-Al2O3 supports prepared by powder compaction and sintering, the halloysite nanotube-based mats (HNMs) show higher flux, better adsorption of zeolite seeds, adhesion of zeolite membranes and lower Al leaching. Four types of zeolite membranes supported on HNMs have been successfully synthesized with either in situ crystallization or a secondary growth method, demonstrating good universality of HNMs for supporting zeolite membranes.

  7. Preparation of Sulfonated Poly(aryl ether sulfone) Electrospun Mat/Phosphosilicate Composite Proton Exchange Membrane

    NASA Astrophysics Data System (ADS)

    Wang, Limei; Dou, Liyan; Guan, Guoying

    2017-03-01

    Side-chain-type sulfonated poly(aryl ether sulfone) (SPES) was synthesized and then electrospun into mats. Phosphosilicate glass (PS) via in situ sol-gel synthesis was enclosed in the mats to form a new reinforced composite membrane. The SPES/PS composite membranes showed satisfactory dimensional change behavior with varying humidity. Especially, the composite membrane exhibits excellent proton conductivity at harsh measurement conditions of low humidity at 80°C. The composite membrane with outstanding combined properties has potential applications for high temperature polymer electrolyte membrane fuel cells.

  8. Preparation of Sulfonated Poly(aryl ether sulfone) Electrospun Mat/Phosphosilicate Composite Proton Exchange Membrane

    NASA Astrophysics Data System (ADS)

    Wang, Limei; Dou, Liyan; Guan, Guoying

    2017-01-01

    Side-chain-type sulfonated poly(aryl ether sulfone) (SPES) was synthesized and then electrospun into mats. Phosphosilicate glass (PS) via in situ sol-gel synthesis was enclosed in the mats to form a new reinforced composite membrane. The SPES/PS composite membranes showed satisfactory dimensional change behavior with varying humidity. Especially, the composite membrane exhibits excellent proton conductivity at harsh measurement conditions of low humidity at 80°C. The composite membrane with outstanding combined properties has potential applications for high temperature polymer electrolyte membrane fuel cells.

  9. 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.

  10. 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.

  11. Evaluation of gallic acid loaded zein sub-micron electrospun fibre mats as novel active packaging materials.

    PubMed

    Neo, Yun Ping; Swift, Simon; Ray, Sudip; Gizdavic-Nikolaidis, Marija; Jin, Jianyong; Perera, Conrad O

    2013-12-01

    The applicability of gallic acid loaded zein (Ze-GA) electrospun fibre mats towards potential active food packaging material was evaluated. The surface chemistry of the electrospun fibre mats was determined using X-ray photon spectroscopy (XPS). The electrospun fibre mats showed low water activity and whitish colour. Thermogravimetric analysis (TGA) and Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy revealed the stability of the fibre mats over time. The Ze-GA fibre mats displayed similar rapid release profiles, with Ze-GA 20% exhibiting the fastest release rate in water as compared to the others. Gallic acid diffuses from the electrospun fibres in a Fickian diffusion manner and the data obtained exhibited a better fit to Higuchi model. L929 fibroblast cells were cultured on the electrospun fibres to demonstrate the absence of cytotoxicity. Overall, the Ze-GA fibre mats demonstrated antibacterial activity and properties consistent with those considered desirable for active packaging material in the food industry.

  12. Novel naturally crosslinked electrospun nanofibrous chitosan mats for guided bone regeneration membranes: material characterization and cytocompatibility.

    PubMed

    Norowski, Peter A; Fujiwara, Tomoko; Clem, William C; Adatrow, Pradeep C; Eckstein, Eugene C; Haggard, Warren O; Bumgardner, Joel D

    2015-05-01

    Guided bone regeneration (GBR) barrier membranes are used to prevent soft tissue infiltration into the graft space during dental procedures that involve bone grafting. Chitosan materials have shown promise as GBR barrier membranes, due to their biocompatibility and predictable biodegradability, but degradation rates may still be too high for clinical applications. In this study, chitosan GBR membranes were electrospun using chitosan (70% deacetylated, 312 kDa, 5.5 w/v%), with or without the addition of 5 or 10 mm genipin, a natural crosslinking agent, in order to extend the degradation to meet the clinical target time frame of 4-6 months. Membranes were evaluated for fibre diameter, tensile strength, biodegradation rate, bond structure and cytocompatibility. Genipin addition, at 5 or 10 mm, resulted in median fibre diameters 184, 144 and 154 nm for uncrosslinked, 5 mm and 10 mm crosslinked, respectively. Crosslinking, examined by Fourier transform infrared spectroscopy, showed a decrease in N-H stretch as genipin levels were increased. Genipin-crosslinked mats exhibited only 22% degradation based on mass loss, as compared to 34% for uncrosslinked mats at 16 weeks in vitro. The ultimate tensile strength of the mats was increased by 165% to 32 MPa with 10 mm crosslinking as compared to the uncrosslinked mats. Finally, genipin-crosslinked mats supported the proliferation of SAOS-2 cells in a 5 day growth study, similar to uncrosslinked mats. These results suggest that electrospun chitosan mats may benefit from genipin crosslinking and have the potential to meet clinical degradation time frames for GBR applications.

  13. Electrospun fibrous mats with high porosity as potential scaffolds for skin tissue engineering.

    PubMed

    Zhu, Xinli; Cui, Wenguo; Li, Xiaohong; Jin, Yan

    2008-07-01

    Diffusional limitations of mass transport have adverse effects on engineering tissues that normally have high vascularity and cellularity. The current electrospinning method is not always successful to create micropores to encourage cell infiltration within the scaffold, especially when relatively large-sized pores are required. In this study, a slow rotating frame cylinder was developed as the collector to extend the pore size and increase the porosity of electrospun fibrous scaffolds. Fibrous mats with porosity as high as 92.4% and average pore size of 132.7 microm were obtained. Human dermal fibroblasts (HDFs) were seeded onto these mats, which were fixed on a cell-culture ring to prevent the shrinkage and contraction during the incubation. The viability test indicated that significantly more HDFs were generated on highly porous fibrous mats. Toluidine blue staining showed that the highly porous scaffold provided mechanical support for cells to maintain uniform distribution. The cross-section observations indicated that cells migrated and infiltrated more than 100 microm inside highly porous fibrous mats after 5 d incubation. The immunohistochemistry analysis demonstrated that cells began secreting collagen, which is the main constituent of extracellular matrix. It is supposed that highly porous electrospun fibrous scaffolds could be constructed by this elaboration and may be used for skin tissue engineering.

  14. 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. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

  15. Control of protein adsorption on functionalized electrospun fibers.

    PubMed

    Grafahrend, Dirk; Calvet, Julia Lleixa; Klinkhammer, Kristina; Salber, Jochen; Dalton, Paul D; Möller, Martin; Klee, Doris

    2008-10-15

    Electrospun fibers that are protein resistant and functionalized with bioactive signals were produced by solution electrospinning amphiphilic block copolymers. Poly (ethylene glycol)-block-poly(D,L-lactide) (PEG-b-PDLLA) was synthesized in two steps, with a PEG segment of 10 kDa, while the PDLLA block ranged from 20 to 60 kDa. Depending on the PEG and PDLLA segment ratio, as well as solvent selection, the hydrophilicity and protein adsorption could be altered on the electrospun mesh. Furthermore, an alpha-acetal PEG-b-PDLLA was synthesized that allowed the conjugation of active molecules, resulting in surface functionalization of the electrospun fiber. Electrospun material with varying morphologies and diameter were electrospun from 10, 20, and 30 wt.% solutions. Sessile drop measurements showed a reduction in the contact angle from 120 degrees for pure poly(D,L-lactide) with increasing PEG/PDLLA ratio. All electrospun block PEG-b-PDLLA fibers had hydrophilic properties, with contact angles below 45 degrees . The fibers were collected onto six-arm star-poly(ethylene glycol) (star-PEG) coated silicon wafers and incubated with fluorescently labeled proteins. All PEG-b-PDLLA fibers showed no detectable adsorption of bovine serum albumin (BSA) independent of their composition while a dependence between hydrophobic block length was observed for streptavidin adsorption. Fibers of block copolymers with PDLLA blocks smaller than 39 kDa showed no adsorption of BSA or streptavidin, indicating good non-fouling properties. Fibers were surface functionalized with N(epsilon)-(+)-biotinyl-L-lysine (biocytin) or RGD peptide by attaching the molecule to the PEG block during synthesis. Protein adsorption measurements, and the controlled interaction of biocytin with fluorescently labeled streptavidin, showed that the electrospun fibers were both resistant to protein adsorption and are functionalized. Fibroblast adhesion was contrasting between the unfunctionalized and RGD

  16. HMDSO-plasma coated electrospun fibers of poly(cyclodextrin)s for antifungal dressings.

    PubMed

    Costoya, Alejandro; Ballarin, Florencia Montini; Llovo, Jose; Concheiro, Angel; Abraham, Gustavo A; Alvarez-Lorenzo, Carmen

    2016-11-20

    Electrospun mats containing cyclodextrin polymers (poly-αCD or poly-βCD) were developed to act as wound dressings showing tunable release rate of the antifungal agent fluconazole incorporated forming inclusion complexes. Poly-αCD and poly-βCD were prepared via cross-linking with epichlorohydrin (EPI) as water-soluble large molecular weight polymers. Then, polyCDs forming complexes with fluconazole were mixed with poly-(ε-caprolactone) (PCL) or poly(N-vinylpyrrolidone) (PVP) for electrospinning. Obtained bead-free fibers showed a random distribution, diameters in the 350-850nm range, and a variety of physical stability behaviors in aqueous environment. Mats were coated by hexamethyldisiloxane (HMDSO) plasma polymerization to create a hydrophobic layer that prevented rapid drug diffusion. HMDSO coating was evidenced by the Si content of mat surface (EDX analysis) and by the increase in the water contact angle (up to 130°). In physiological-mimicking medium, non-treated mats showed burst release of fluconazole, whereas HMDSO-coated mats sustained the release and delayed disintegration of PVP-based mats. Antifungal tests evidenced that both coated and non-coated mats efficiently inhibited the growth of Candida albicans.

  17. Vitamin-loaded electrospun cellulose acetate nanofiber mats as transdermal and dermal therapeutic agents of vitamin A acid and vitamin E.

    PubMed

    Taepaiboon, Pattama; Rungsardthong, Uracha; Supaphol, Pitt

    2007-09-01

    The present contribution reports the use of mats of electrospun cellulose acetate (CA; acetyl content=39.8%; Mw=30,000 Da) nanofibers as carriers for delivery of the model vitamins, all-trans retinoic acid or vitamin A acid (Retin-A) and alpha-tocopherol or vitamin E (Vit-E). The amounts of Vit-E and Retin-A loaded in the base CA solution [17% w/v in 2:1 v/v acetone/N,N-dimethylacetamide (DMAc)] were 5 and 0.5 wt% (based on the weight of CA), respectively. Cross-sectionally round and smooth fibers were obtained. The average diameters of these fibers ranged between 247 and 265 nm. The total immersion of the vitamin-loaded as-spun CA fiber mats in the acetate buffer solutions containing either 0.5 vol % Tween 80 or 0.5 vol % Tween 80 and 10 vol % methanol was used to arrive at the cumulative release of the vitamins from the fiber mat samples. The same was also conducted on the vitamin-loaded solution-cast CA films for comparison. In most cases, the vitamin-loaded as-spun fiber mats exhibited a gradual and monotonous increase in the cumulative release of the vitamins over the test periods (i.e., 24 h for Vit-E-loaded samples and 6 h for Retin-A-loaded ones), while the corresponding as-cast films exhibited a burst release of the vitamins.

  18. 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.

  19. Electrospun fibers with plasmid bFGF polyplex loadings promote skin wound healing in diabetic rats.

    PubMed

    Yang, Ye; Xia, Tian; Chen, Fang; Wei, Wei; Liu, Chaoyu; He, Shuhui; Li, Xiaohong

    2012-01-01

    Deep or chronic skin wounds are difficult to heal spontaneously due to the lack of scaffold to guide cell growth and reduced levels and activities of endogenous growth factors. Emulsion electrospinning process integrated with DNA condensation techniques indicated potentials to gradually release DNA, but no attempt has been made to clarify the advantages in promoting tissue regeneration and wound recovery. In this study, polyplexes of basic fibroblast growth factor-encoding plasmid (pbFGF) with poly(ethylene imine) were incorporated into electrospun fibers with a core-sheath structure, and poly(ethylene glycol) was included into the fiber sheath to allow a sustained release of pbFGF for 4 weeks. In vitro tests on mouse embryo fibroblasts indicated that pbFGF-loaded fibrous mats enhanced cell proliferation by the autocrine bFGF, and an effective cell transfection proceeded for over 28 days. Skin wounds were created in the dorsal area of diabetic rats for in vivo evaluation of skin regeneration after being covered with pbFGF-loaded fibrous mats. The gradual pbFGF release revealed significantly higher wound recovery rate with improved vascularization, enhanced collagen deposition and maturation, complete re-epithelialization and formation of skin appendages. The above results demonstrate the potential use of pbFGF-loaded electrospun fibrous mats to accelerate the healing of skin ulcers for patients with diabetic mellitus.

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

    PubMed

    Arslan, Osman; Aytac, Zeynep; Uyar, Tamer

    2016-08-03

    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.

  1. 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.

  2. Evaluation of Degradation of Ceramic Fiber Mat by Acoustic Emission

    NASA Astrophysics Data System (ADS)

    Ito, Kaita; Enoki, Manabu; Takahashi, Hidetomo

    2005-04-01

    Alumina-silica fiber mat is widely used as thermal insulator because of its good stability under high temperature environment. However, this material degrades gradually during long-term use under pressure and elevated temperature. In this study, cyclic compression tests of the mat were conducted and monitored acoustic emission (AE) of the mat both at room temperature and elevated temperature. The degradation of mat was evaluated by AE parameters.

  3. Evaluation of Degradation of Ceramic Fiber Mat by Acoustic Emission

    SciTech Connect

    Ito, Kaita; Enoki, Manabu; Takahashi, Hidetomo

    2005-04-09

    Alumina-silica fiber mat is widely used as thermal insulator because of its good stability under high temperature environment. However, this material degrades gradually during long-term use under pressure and elevated temperature. In this study, cyclic compression tests of the mat were conducted and monitored acoustic emission (AE) of the mat both at room temperature and elevated temperature. The degradation of mat was evaluated by AE parameters.

  4. Drug-loaded electrospun mats of poly(vinyl alcohol) fibres and their release characteristics of four model drugs

    NASA Astrophysics Data System (ADS)

    Taepaiboon, Pattama; Rungsardthong, Uracha; Supaphol, Pitt

    2006-05-01

    Mats of PVA nanofibres were successfully prepared by the electrospinning process and were developed as carriers of drugs for a transdermal drug delivery system. Four types of non-steroidal anti-inflammatory drug with varying water solubility property, i.e. sodium salicylate (freely soluble in water), diclofenac sodium (sparingly soluble in water), naproxen (NAP), and indomethacin (IND) (both insoluble in water), were selected as model drugs. The morphological appearance of the drug-loaded electrospun PVA mats depended on the nature of the model drugs. The 1H-nuclear magnetic resonance results confirmed that the electrospinning process did not affect the chemical integrity of the drugs. Thermal properties of the drug-loaded electrospun PVA mats were analysed by differential scanning calorimetry and thermogravimetric analysis. The molecular weight of the model drugs played a major role on both the rate and the total amount of drugs released from the as-prepared drug-loaded electrospun PVA mats, with the rate and the total amount of the drugs released decreasing with increasing molecular weight of the drugs. Lastly, the drug-loaded electrospun PVA mats exhibited much better release characteristics of the model drugs than drug-loaded as-cast films.

  5. The compression of wood/thermoplastic fiber mats during consolidation

    Treesearch

    Karl R. Englund; Michael P. Wolcott; John C. Hermanson

    2004-01-01

    Secondary processing of non-woven wood and wood/thermoplastic fiber mats is generally performed using compression molding, where heated platens or dies form the final product. Although the study and use of wood-fiber composites is widespread, few research efforts have explicitly described the fundamentals of mat consolidation. In contrast, the wood composite literature...

  6. The mechanical properties of individual, electrospun fibrinogen fibers

    PubMed Central

    Carlisle, Christine R.; Coulais, Corentin; Namboothiry, Manoj; Carroll, David L.; Hantgan, Roy R.; Guthold, Martin

    2010-01-01

    We used a combined atomic force microscopic (AFM)/fluorescence microscopic technique to study the mechanical properties of individual, electrospun fibrinogen fibers in aqueous buffer. Fibers (average diameter 208 nm) were suspended over 12 μm-wide grooves in a striated, transparent substrate. The AFM, situated above the sample, was used to laterally stretch the fibers and to measure the applied force. The fluorescence microscope, situated below the sample, was used to visualize the stretching process. The fibers could be stretched to 2.3 times their original length before breaking; the breaking stress was 22 × 106 Pa. We collected incremental stress–strain curves to determine the viscoelastic behavior of these fibers. The total stretch modulus was 17.5 × 106 Pa and the relaxed elastic modulus was 7.2 × 106 Pa. When held at constant strain, electrospun fibrinogen fibers showed a fast and slow stress relaxation time of 3 and 55 s. Our fibers were spun from the typically used 90% 1,1,1,3,3,3-hexafluoro-2-propanol (90-HFP) electrospinning solution and re-suspended in aqueous buffer. Circular dichroism spectra indicate that α-helical content of fibrinogen is ~70% higher in 90-HFP than in aqueous solution. These data are needed to understand the mechanical behavior of electrospun fibrinogen structures. Our technique is also applicable to study other nanoscopic fibers. PMID:19058845

  7. Encapsulated particles attached on electrospun fibers by in situ combination of electrospinning and coaxial electrospraying.

    PubMed

    Bae, Harim; Lee, Jonghwi

    2014-10-01

    Electrohydrodynamic jetting has been widely used as a promising strategy for the development of functionalized scaffolds to mimic natural extracellular matrix. The current electrospun scaffolds achieve functionality through additional mechanical or chemical treatments, and their life-time depends on fiber degradation. An innovative in situ approach used to attach core-shell poly(D,L-lactide-co-glycolide) (PLGA) particles on fibrous mats is described here. This particle/fiber composite was prepared by electrohydrodynamic jetting of countercharged nozzles (EJC) based on neutralization between electrospun nanofibers and coaxial electrosprayed droplets. The PLGA particles were successfully attached onto both water-soluble polyvinylpyrrolidone and hydrophobic poly(L-lactide-co-D,L-lactide). The resulting release rates of encapsulated model compounds were independently controlled by fiber degradation. Encapsulation efficiency and the dimensions of particles and fibers were easily engineered by changing solvents. The particle/fiber composite prepared by EJC could be a superior material for developing future biomaterials with architectured biological and mechanical properties.

  8. Anisotropic oxygen plasma etching of colloidal particles in electrospun fibers.

    PubMed

    Ding, Tao; Tian, Ye; Liang, Kui; Clays, Koen; Song, Kai; Yang, Guoqiang; Tung, Chen-Ho

    2011-02-28

    Oxygen plasma etching of electrospun polymer fibers containing spherical colloids is presented as a new approach towards anisotropic colloidal nanoparticles. The detailed morphology of the resulting nanoparticles can be precisely controlled in a continuous way. The same approach is also amenable to prepare inorganic nanoparticles with double-sided patches.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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.

  14. Electrospun antibacterial polyurethane-cellulose acetate-zein composite mats for wound dressing.

    PubMed

    Unnithan, Afeesh Rajan; Gnanasekaran, Gopalsamy; Sathishkumar, Yesupatham; Lee, Yang Soo; Kim, Cheol Sang

    2014-02-15

    In this study, an antibacterial electrospun nanofibrous scaffolds with diameters around 400-700 nm were prepared by physically blending polyurethane (PU) with two biopolymers such as cellulose acetate (CA) and zein. Here, PU was used as the foundation polymer, was blended with CA and zein to achieve desirable properties such as better hydrophilicity, excellent cell attachment, proliferation and blood clotting ability. To prevent common clinical infections, an antimicrobial agent, streptomycin sulfate was incorporated into the electrospun fibers and its antimicrobial ability against the gram negative and gram positive bacteria were examined. The interaction between fibroblasts and the PU-CA and PU-CA-zein-drug scaffolds such as viability, proliferation, and attachment were characterized. PU-CA-zein-drug composite nanoscaffold showed enhanced blood clotting ability in comparison with pristine PU nanofibers. The presence of CA and zein in the nanofiber membrane improved its hydrophilicity, bioactivity and created a moist environment for the wound, which can accelerate wound recovery.

  15. 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. © 2016 Wiley Periodicals, Inc.

  16. 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.

  17. Electrospun ceramic fibers: Composition, structure and the fate of precursors

    NASA Astrophysics Data System (ADS)

    Tuttle, R. W.; Chowdury, A.; Bender, E. T.; Ramsier, R. D.; Rapp, J. L.; Espe, M. P.

    2008-06-01

    Fibers are electrospun from aluminum acetate/polymer mixtures and characterized by an array of techniques before and after annealing at 1200 °C. We demonstrate that sodium and boron present in the initial starting materials as adducts and stabilizers remain incorporated into the resulting fibers after annealing and pyrolysis of the host polymer. The influence of these minor constituents on the surfaces of the fibers is suggested by infrared and X-ray photoelectron spectroscopic data. The presence of these species may impact potential chemical applications of small diameter ceramic fibers, such as their use as catalytic supports or for chemical decomposition.

  18. Thermally stable hydrophobicity in electrospun silica/polydimethylsiloxane hybrid fibers

    NASA Astrophysics Data System (ADS)

    Wei, Zhonglin; Li, Jianjun; Wang, Chao; Cao, Jungang; Yao, Yongtao; Lu, Haibao; Li, Yibin; He, Xiaodong

    2017-01-01

    In order to improve practical performances of silica-based inorganic/organic hybrid fibers, silica/polydimethylsiloxane hydrophobic fibers were successfully prepared by electrospinning. Silica sol and polydimethylsiloxane can be mixed homogeneously and become stable precursor solution in dichloromethane, which allows the transformation of silica/polydimethylsiloxane precursor solution into ultrafine fibers. Flame can ignite organic groups in polydimethylsiloxane directly and destroy the hydrophobicity of hybrid fibers, but hydrophobic feature may survive if electrospun hybrid membrane is combined with thin stainless-steel-304 gauze of 150 meshes due to its thermally stable hydrophobicity (>600 °C).

  19. 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

  20. Effects of humidity and solution viscosity on electrospun fiber morphology.

    PubMed

    Nezarati, Roya M; Eifert, Michelle B; Cosgriff-Hernandez, Elizabeth

    2013-10-01

    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. 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.

  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. Electrospun ultra-fine cellulose acetate fibrous mats containing tannic acid-Fe+++ complexes

    USDA-ARS?s Scientific Manuscript database

    Cellulose acetate (CA) fibrous mats with improved mechanical and antioxidant properties were produced by a simple, scalable and cost-effective electrospinning method. Fibers loaded with small amounts of TA-Fe+++ complexes showed an increase in tensile strength of approximately 117% when compared to ...

  4. Photocatalytic Cellulosic Electrospun Fibers for the Degradation of Potent Cyanobacteria Toxin Microcystin-LR

    DTIC Science & Technology

    2012-01-01

    Photocatalytic cellulosic electrospun fibers for the degradation of potent cyanobacteria toxin microcystin-LR† Nicholas M. Bedford,ab Miguel Pelaez,c...photocatalytic decomposition of the potent cyanobacteria toxin microcystin-LR (MC-LR). Electrospun fibers of cellulose acetate were converted to succinylated...00-2012 4. TITLE AND SUBTITLE Photocatalytic cellulosic electrospun fibers for the degradation of potent cyanobacteria toxin microcystin-LR 5a

  5. Electrospun fibers for dental and craniofacial applications.

    PubMed

    Li, Guo; Zhang, Tong; Li, Meng; Fu, Na; Fu, Yao; Ba, Kai; Deng, Shuwen; Jiang, Yan; Hu, Jing; Peng, Qiang; Lin, Yunfeng

    2014-05-01

    Electrospinning has been employed extensively in tissue engineering to generate nanofibrous scaffolds from either natural or synthetic biodegradable polymers. Three-dimensional electrospun scaffolds can create a multi-scale environment capable of facilitating cell adhesion, proliferation, and differentiation. One such multi-scale scaffold incorporates nanofibrous features to mimic the extracellular matrix along with a porous network for the regeneration of a variety of tissues. This review will discuss nanofibrous scaffolds and their tissue-engineering applications in bone, cartilage, periodontium, tooth, and incorporated drug delivery systems. Combination with other technologies, electrospun scaffolds can contribute to the field of craniofacial regeneration and advance technology for tissue-engineered replacements in many physiological systems in near future.

  6. Effect of thermal annealing on the surface properties of electrospun polymer fibers.

    PubMed

    Chen, Jiun-Tai; Chen, Wan-Ling; Fan, Ping-Wen; Yao, I-Chun

    2014-02-01

    Electrospun polymer fibers are gaining importance because of their unique properties and applications in areas such as drug delivery, catalysis, or tissue engineering. Most studies to control the morphology and properties of electrospun polymer fibers focus on changing the electrospinning conditions. The effects of post-treatment processes on the morphology and properties of electrospun polymer fibers, however, are little studied. Here, the effect of thermal annealing on the surface properties of electrospun polymer fibers is investigated. Poly(methyl methacrylate) and polystyrene fibers are fist prepared by electrospinning, followed by thermal annealing processes. Upon thermal annealing, the surface roughness of the electrospun polymer fibers decreases. The driving force of the smoothing process is the minimization of the interfacial energy between polymer fibers and air. The water contact angles of the annealed polymer fibers also decrease with the annealing time.

  7. Cell proliferation on PVA/sodium alginate and PVA/poly(γ-glutamic acid) electrospun fiber.

    PubMed

    Yang, Jen Ming; Yang, Jhe Hao; Tsou, Shu Chun; Ding, Chian Hua; Hsu, Chih Chin; Yang, Kai Chiang; Yang, Chun Chen; Chen, Ko Shao; Chen, Szi Wen; Wang, Jong Shyan

    2016-09-01

    To overcome the obstacles of easy dissolution of PVA nanofibers without crosslinking treatment and the poor electrospinnability of the PVA cross-linked nanofibers via electrospinning process, the PVA based electrospun hydrogel nanofibers are prepared with post-crosslinking method. To expect the electrospun hydrogel fibers might be a promising scaffold for cell culture and tissue engineering applications, the evaluation of cell proliferation on the post-crosslinking electrospun fibers is conducted in this study. At beginning, poly(vinyl alcohol) (PVA), PVA/sodium alginate (PVASA) and PVA/poly(γ-glutamic acid) (PVAPGA) electrospun fibers were prepared by electrospinning method. The electrospun PVA, PVASA and PVAPGA nanofibers were treated with post-cross-linking method with glutaraldehyde (Glu) as crosslinking agent. These electrospun fibers were characterized with thermogravimetry analysis (TGA) and their morphologies were observed with a scanning electron microscope (SEM). To support the evaluation and explanation of cell growth on the fiber, the study of 3T3 mouse fibroblast cell growth on the surface of pure PVA, SA, and PGA thin films is conducted. The proliferation of 3T3 on the electrospun fiber surface of PVA, PVASA, and PVAPGA was evaluated by seeding 3T3 fibroblast cells on these crosslinked electrospun fibers. The cell viability on electrospun fibers was conducted with water-soluble tetrazolium salt-1 assay (Cell Proliferation Reagent WST-1). The morphology of the cells on the fibers was also observed with SEM. The results of WST-1 assay revealed that 3T3 cells cultured on different electrospun fibers had similar viability, and the cell viability increased with time for all electrospun fibers. From the morphology of the cells on electrospun fibers, it is found that 3T3 cells attached on all electrospun fiber after 1day seeded. Cell-cell communication was noticed on day 3 for all electrospun fibers. Extracellular matrix (ECM) productions were found and

  8. The effect of poly (lactic-co-glycolic) acid composition on the mechanical properties of electrospun fibrous mats.

    PubMed

    Liu, X; Aho, J; Baldursdottir, S; Bohr, A; Qu, H; Christensen, L P; Rantanen, J; Yang, M

    2017-08-30

    The aim of this study was to investigate the influence of polymer molecular structure on the electrospinnability and mechanical properties of electrospun fibrous mats (EFMs). Polymers with similar molecular weight but different composition ratios (lactic acid (LA) and glycolic acid (GA)) were dissolved in binary mixtures of N,N-dimethylformamide (DMF) and tetrahydrofuran (THF). The intrinsic viscosity and rheological properties of polymer solutions were investigated prior to electrospinning. The morphology and mechanical properties of the resulting EFMs were characterized by scanning electron microscope (SEM) and dynamic mechanical analysis (DMA). Sufficiently high inter-molecular interactions were found to be a prerequisite to ensure the formation of fibers in the electrospinning process, regardless the polymer composition. The higher the amount of GA in the polymer composition, the more ordered and entangled molecules were formed after electrospinning from the solution in THF-DMF, which resulted in higher Young's modulus and tensile strength of the EFMs. In conclusion, this study shows that the mechanical properties of EFMs, which depend on the polymer molecule-solvent affinity, can be predicted by the inter-molecular interactions in the starting polymer solutions and over the drying process of electrospinning. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. 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.

  10. Study of superhydrophobic electrospun nanocomposite fibers for energy systems.

    PubMed

    Asmatulu, Ramazan; Ceylan, Muhammet; Nuraje, Nurxat

    2011-01-18

    Polystyrene (PS) and polyvinyl chloride (PVC) fibers incorporated into TiO(2) nanoparticles and graphene nanoflakes were fabricated by an electrospinning technique, and then the surface morphology and superhydrophobicity of these electrospun nanocomposite fibers were investigated. Results indicated that the water contact angle of the nanocomposite fiber surfaces increases to 178° on the basis of the fiber diameter, material type, nanoscale inclusion, heat treatment, and surface porosity/roughness. This is a result of the formation of the Cassie-Baxter state in the fibers via the nanoparticle decoration, bead formation, and surface energy of the nanofiber surface. Consequently, these superhydrophobic nanocomposite fibers can be utilized in designing photoelectrodes of dye-sensitized solar cells (DSSCs) as self-cleaning and anti-icing materials for the long-term efficiency of the cells.

  11. Electrospun antibacterial chitosan-based fibers.

    PubMed

    Ignatova, Milena; Manolova, Nevena; Rashkov, Iliya

    2013-07-01

    Chitosan is non-toxic, biocompatible, and biodegradable polysaccharide from renewable resources, known to have inherent antibacterial activity, which is mainly due to its polycationic nature. The combining of all assets of chitosan and its derivatives with the unique properties of electrospun nanofibrous materials is a powerful strategy to prepare new materials that can find variety of biomedical applications. In this article the most recent studies on different approaches for preparation of antibacterial fibrous materials from chitosan and its derivatives such as electrospinning, coating, and electrospinning-electrospraying, loading of drugs or bioactive nanoparticles are summarized.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

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

    PubMed

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

    2009-01-09

    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.

  17. Electrospun Fibrous Mat with pH-Switchable Superwettability That Can Separate Layered Oil/Water Mixtures.

    PubMed

    Li, Jin-Jin; Zhou, Yin-Ning; Jiang, Zhi-Dong; Luo, Zheng-Hong

    2016-12-20

    Oil/water separation has inspired much research interest because of the damages caused to our natural environment due to oily wastewater. As a leader of advanced separation materials, electrospun polymeric fibrous mats having the properties of special surface wettability, high specific surface area, and high porosity will be a good membrane material for the separation of oily wastewater. Herein, we first prepared pH-responsive polymer poly(dimethylsiloxane)-block-poly(4-vinylpyridine) (PDMS-b-P4VP) mat using electrospinning technology. The PDMS-b-P4VP fibrous mat with a thickness of around 250 μm exhibits good pH-switchable oil/water wettability and is able to effectively separate oil or water from layered oil/water mixtures by gravity driven through adjusting the pH value. Stemming from its porous structure and pH-switchable superwettability, the electrospun PDMS-b-P4VP fibrous mat achieved controllable separations with high fluxes of approximately 9000 L h(-1) m(-2) for oil (hexane) and 27 000 L h(-1) m(-2) for water. In addition, extended studies on the polymer/silica nanoparticulate (silica NP) composite fibrous mats show that the addition of an inorganic component improves the thermal stability, pH-switchable wettability, and separation performance of the fibrous mats (approximately 9000 L h(-1) m(-2) for hexane and 32 000 L h(-1) m(-2) for water). It can be concluded from the results that both polymer fibrous mats and silica-filled composite fibrous mats are good candidates for on-demand layered oil/water mixture separation.

  18. 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.

  19. 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. © The Author(s) 2015.

  20. Electrospun Polymer Fibers for Electronic Applications

    PubMed Central

    Luzio, Alessandro; Canesi, Eleonora Valeria; Bertarelli, Chiara; Caironi, Mario

    2014-01-01

    Nano- and micro- fibers of conjugated polymer semiconductors are particularly interesting both for applications and for fundamental research. They allow an investigation into how electronic properties are influenced by size confinement and chain orientation within microstructures that are not readily accessible within thin films. Moreover, they open the way to many applications in organic electronics, optoelectronics and sensing. Electro-spinning, the technique subject of this review, is a simple method to effectively form and control conjugated polymer fibers. We provide the basics of the technique and its recent advancements for the formation of highly conducting and high mobility polymer fibers towards their adoption in electronic applications. PMID:28788493

  1. Superhydrophobic silicone fiber mats fabricated by electrospinning from solution

    NASA Astrophysics Data System (ADS)

    Ludwig, Bonnie; Clark, Aneta; Snow, Steven; Hill, Randal; Schmidt, Randall; Fogg, Brad; Lo, Peter

    2007-03-01

    Fine silicone fibers of 1 -- 20 μm diameter were fabricated from solution via electrospinning. These are the first examples of fine fibers prepared from silicone homopolymers. Fiber morphology (beaded, ribbon-like, smooth) and diameter were controlled. The nanoscale surface roughness of nonwoven fiber mats created with silicone fibers produced a superhydrophobic surface that had a water contact angle of ˜160^o. The superhydrophobic surface was made reversibly hydrophilic with exposure to oxygen plasma. The combination of high surface area and superhydrophobicity suggests potential applications in the areas of water-repellent textiles, filtration, adsorption and chemical separations, wound dressings, and fuel cells.

  2. Encapsulation of T4 bacteriophage in electrospun poly(ethylene oxide)/cellulose diacetate fibers.

    PubMed

    Korehei, Reza; Kadla, John F

    2014-01-16

    Phage therapy is a potentially beneficial approach to food preservation and storage. Sustained delivery of bacteriophage can prevent bacterial growth on contaminated food surfaces. Using coaxial electrospinning bacteriophage can be encapsulated in electrospun fibers with high viability. The resulting bio-based electrospun fibers may have potential as a food packaging material. In the present work, T4 bacteriophage (T4 phage) was incorporated into core/shell electrospun fibers made from poly(ethylene oxide) (PEO), cellulose diacetate (CDA), and their blends. Fibers prepared using PEO as the shell polymer showed an immediate burst release of T4 phage upon submersion in buffer. The blending of CDA with PEO significantly decreased the rate of phage release, with no released T4 phage being detected from the solely CDA fibers. Increasing the PEO molecular weight increased the electrospun fiber diameter and viscosity of the releasing medium, which resulted in a relatively slower T4 phage release profile. SEM analyses of the electrospun fiber morphologies were in good agreement with the T4 phage release profiles. Depending on the PEO/CDA ratio, the post-release electrospun fiber morphologies varied from discontinuous fibers to minimally swollen fibers. From these results it is suggested that the T4 phage release mechanism is through solvent activation/polymer dissolution in the case of the PEO fibers and/or by diffusion control from the PEO/CDA blend fibers.

  3. Subtle regulation of the micro- and nanostructures of electrospun polystyrene fibers and their application in oil absorption

    NASA Astrophysics Data System (ADS)

    Lin, Jinyou; Ding, Bin; Yang, Jianmao; Yu, Jianyong; Sun, Gang

    2011-12-01

    In this study, we conducted a subtle regulation of micro- and nanostructures of electrospun polystyrene (PS) fibers via tuning the molecular weights of the polymers with different sources, solvent compositions, and solution concentration. The surface morphology and porous structures of as-prepared PS fibers were characterized, and a full and intuitive observation of the porous structures as well as a tentative account of the formation of porous structures was presented. Additionally, the porous PS fibrous mats showed much higher oil absorption capacities than those of commercial polypropylene fibers in the form of a non-woven fabric, which displays a bight future for oil spill cleanups. We believe that such regulation of micro- and nanostructures of the PS fibers will widen the range of their applications in self-cleaning materials, ultra-high sensitivity sensors, tissue engineering, ion exchange materials, etc.

  4. Subtle regulation of the micro- and nanostructures of electrospun polystyrene fibers and their application in oil absorption.

    PubMed

    Lin, Jinyou; Ding, Bin; Yang, Jianmao; Yu, Jianyong; Sun, Gang

    2012-01-07

    In this study, we conducted a subtle regulation of micro- and nanostructures of electrospun polystyrene (PS) fibers via tuning the molecular weights of the polymers with different sources, solvent compositions, and solution concentration. The surface morphology and porous structures of as-prepared PS fibers were characterized, and a full and intuitive observation of the porous structures as well as a tentative account of the formation of porous structures was presented. Additionally, the porous PS fibrous mats showed much higher oil absorption capacities than those of commercial polypropylene fibers in the form of a non-woven fabric, which displays a bight future for oil spill cleanups. We believe that such regulation of micro- and nanostructures of the PS fibers will widen the range of their applications in self-cleaning materials, ultra-high sensitivity sensors, tissue engineering, ion exchange materials, etc.

  5. 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.

  6. Influence of the structure of poly (L-lactic acid) electrospun fibers on the bioactivity of endothelial cells: proliferation and inflammatory cytokines expression.

    PubMed

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

    2017-02-01

    Electrospinning has been used to fabricate random and aligned poly (L-lactic acid) (PLLA) fibers with three kinds of diameter under optimal conditions. The main purpose of this paper was to investigate the influence of the diameter and orientation of fibers on the bioactivity of endothelial cells, especially on the inflammatory cytokines expression. The morphology of electrospun fibers and the cells on the fibers after 3 and 6 days culture were observed by scanning electron microscopy. Also the cell proliferation activity and cell cycle were tested and the results showed that the random fibers were more favorable for endothelial cells growth. The effect of PLLA film (served as a control) and six kinds of PLLA fibers mats on the inflammatory cytokines expression after cells incubated for 2 and 4 days were investigated. It was concluded that there was more intense inflammatory cytokines expression by cells on flat PLLA film than that on electrospun fiber mats. Also the fiber diameter has greater effect on the activity and inflammatory cytokines expression of endothelial cells than the fiber orientation, in which fibers with smaller size has weaker inflammatory reaction.

  7. 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. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  8. 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

  9. Hybrid encapsulation structures based on β-carotene-loaded nanoliposomes within electrospun fibers.

    PubMed

    de Freitas Zômpero, Rafael Henrique; López-Rubio, Amparo; de Pinho, Samantha Cristina; Lagaron, José María; de la Torre, Lucimara Gaziola

    2015-10-01

    Hybrid encapsulation structures based on β-carotene-loaded nanoliposomes incorporated within the polymeric ultrathin fibers produced through electrospinning were developed to improve the photostability of the antioxidant. These novel materials were intended to incorporate β-carotene into water-based food formulations, overcoming the existing limitations associated with its hydrophobic character. Initially, both empty and antioxidant-loaded nanoliposomes were developed and incorporated into polyvinyl alcohol (PVOH) and polyethylene oxide (PEO) solutions. The changes in the solution properties were evaluated to determine their effects on the electrospinning processing. The mixed polymer solutions were subsequently electrospun to produce hybrid nanoliposome-loaded ultrathin fibers. FTIR analysis confirmed the presence of phospholipid molecules inside the electrospun fibers. These ultrathin fibers were evaluated regarding their morphology, diameter, internal β-carotene distribution and stability against UV irradiation. Liposomal release studies from the electrospun fibers were also undertaken, confirming the presence of the liposomal structures after dissolving the electrospun fibers in water.

  10. On the Adhesion performance of a single electrospun fiber

    NASA Astrophysics Data System (ADS)

    Baji, Avinash; Zhou, Limin; Mai, Yiu-Wing; Yang, Zhifang; Yao, Haimin

    2015-01-01

    The micro- and nano-scale fibrillar structures found on the feet of spiders and geckos function as adhesion devices which allow them to adhere to both molecularly smooth and rough surfaces. This adhesion has been argued to arise from intermolecular forces, such as van der Waals (vdW) force, acting at the interface between any two materials in contact. Thus, it is possible to mimic their adhesion using synthetic nanostructured analogs. Herein, we report the first successful pull-off force measurements on a single electrospun fiber and show the potential of using electrospinning to fabricate adhesive analogs. A single fiber is glued to the atomic force microscope cantilever, and its adhesion to a metal substrate is studied by recording the pull-off force/displacement curves. The measured adhesive force of ~18 nN matches closely that of their biological counterparts. Similar to natural structures, the adhesive mechanism of these electrospun structures is controlled by vdW interactions.

  11. Stable nisin food-grade electrospun fibers.

    PubMed

    Soto, Karen M; Hernández-Iturriaga, Montserrat; Loarca-Piña, Guadalupe; Luna-Bárcenas, Gabriel; Gómez-Aldapa, Carlos A; Mendoza, Sandra

    2016-10-01

    Most of antimicrobial peptides interact with food components decreasing their activity, which limit their successful incorporation into packaging material, functional foods and edible films. The aim of this work was to develop a nisin carrier. Nanofibers of amaranth protein and pullulan (50:50) loaded with nisin were obtained by electrospinning. The nanofibers morphology was determined by scanning electron microscopy and fluorescent microscopy. The molecular interactions were characterized by infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. The nisin loading efficiency as well as the antimicrobial activity against Leuconostoc mesenteroides were evaluated. The micrographs of the obtained materials exhibited smooth and continuous fibers with no defects characterized by diameters between 124 and 173 nm. The FTIR analysis showed intermolecular interactions mainly by hydrogen bonding. The electrospinning process improved the thermal properties of the polymeric mixture displacing the Tm peak to higher temperatures and increasing crystallinity. The antimicrobial activity of nisin in broth and agar against L. mesenteroides was maintained after incorporation into fibers. The results presented an outlook for the potential use of protein amaranth nanofibers when incorporating antimicrobials as a food preservation strategy.

  12. Catalytic property of fiber media supported palladium containing alloy nanoparticles and electrospun ceramic fibers biodurability study

    NASA Astrophysics Data System (ADS)

    Shin, Hyeon Ung

    The nanoscale of the supporting fibers may provide enhancements such as restricting the migration of metal catalyst particles. In this work, palladium nanoparticle doped alumina fibers were electrospun into template submicron fibers. These fibers were calcined at temperatures between 650°C and 1150°C to vary the crystal structures of the calcined fibers with the Pd particle size. Higher calcination temperatures led to higher reaction temperatures from 250 to about 450°C for total conversion, indicating the effective reactivity of the fiber-supported catalysts decreased with increase in calcination temperature. Pd-Au alloy nanoparticle doped titania fibers were also fabricated using an electrospinning method and assembled into a fibrous porous medium structure by a vacuum molding process. In reactor tests, the fiber media with Pd-Au alloy nanoparticle catalyst had greater reactivity in conversion of NO and CO gases than that of fiber media with Pd monometallic catalyst alone, attributed to a lower activation energy of the Pd-Au catalyst particles. In carbon monoxide oxidation reaction tests, the results showed that the performance was optimal for a catalyst of composition Pd2Au1 molar ratio that was active at 125°C, which had higher dispersion of active components and better catalytic performance compared to monometallic particle Au/TiO 2 and Pd/TiO2 fiber media. Moreover, the improved reaction activity of Pd2Au1/TiO2 fiber medium was attributed to a decreased in the activation energy. Further experiments were conducted using the electrospun ceramic fibers biodurability study. The properties of nano-sized fiber structures have attracted the attention of recent research on ceramic nanostructures as nonwoven media for applications in hazardous chemical and high temperature environments. However, health and safety concerns of micro and nano scale ceramic materials have not been fully investigated. Little is known about the physicochemical effects of the properties

  13. Facile fabrication of gold nanoparticles-poly(vinyl alcohol) electrospun water-stable nanofibrous mats: efficient substrate materials for biosensors.

    PubMed

    Wang, Juan; Yao, Hong-Bin; He, Dian; Zhang, Chuan-Ling; Yu, Shu-Hong

    2012-04-01

    Electrospun nanofibrous mats are intensively studied as efficient scaffold materials applied in the fields of tissue engineering, catalysis, and biosensors due to their flexibility and porosity. In this paper, we report a facile route to fabricate gold nanoparticles-poly(vinyl alcohol) (Au NPs-PVA) hybrid water stable nanofibrous mats with tunable densities of Au NPs and further demonstrate the potential application of as-prepared Au NPs-PVA nanofibrous mats as efficient biosensor substrate materials. First, through the designed in situ cross-linkage in coelectrospun PVA-glutaraldehyde nanofibers, water insoluble PVA nanofibrous mats with suitable tensile strength were successfully prepared. Then, 3-mercaptopropyltrimethoxysilane (MPTES) was modified on the surface of obtained PVA nanofibrous films, which triggered successful homogeneous decoration of Au NPs through gold-sulfur bonding interactions. Finally, the Au NPs-PVA nanofibrous mats embedded with horseradish peroxidase (HRP) by electrostatic interactions were used as biosensor substrate materials for H(2)O(2) detection. The fabricated HRP-Au NPs/PVA biosensor showed a highly sensitive detection of H(2)O(2) with a detection limit of 0.5 μM at a signal-to-noise ratio of 3. By modifying other different functional nanaoparticles or enzyme on the PVA nanofibrous film will further expand their potential applications as substrate materials of different biosensors.

  14. Multimeric immobilization of alcohol oxidase on electrospun fibers for valid tests of alcoholic saliva.

    PubMed

    Zhao, Long; Liu, Qingjie; Yan, Shili; Chen, Zhoujiang; Chen, Jianmei; Li, Xiaohong

    2013-10-10

    An accurate quantitation of ethanol is of great importance in clinical and forensic analyses. In the current study, alcohol oxidase (AOX) from Pichia pastoris, a multimeric enzyme consisting of eight identical subunits, was immobilized on electrospun polystyrene-co-maleic anhydride (PSMA) fibers for valid tests of alcoholic saliva. Branched polyethyleneimine (PEI) was grafted on PSMA fibers with a density of 0.15 nmol/cm(2) as tethers to allow multipoint covalent binding of enzyme molecules through glutaraldehyde activation, and the secondary and tertiary amino groups of PEI could intensify the interactions with AOX subunits to stabilize the quaternary structure. PSMA-PEI-AOX fibers were less sensitive than free AOX to the incubation temperature and pH, and indicated no detectable subunit release from the immobilized AOX after boiling in the presence of sodium dodecyl sulfate (SDS) and 2-mercaptoethanol. Color strips were established on PSMA-PEI-AOX fibrous mats dyed with indigo Carmine after incubation into ethanol solutions of different concentrations. The color fading ratio remained no significant change after repeat tests for 9 cycles after immersion in 0.2 and 0.8 mg/mL of alcoholic saliva. It was indicated that multipoint immobilization of the multimeric enzyme was essential to improve the enzyme stability by stabilizing both the quaternary structure of the enzyme and the structure of each individual subunit.

  15. Morphology Tuning of Electrospun Liquid Crystal/Polymer Fibers.

    PubMed

    Wang, Junren; Jákli, Antal; West, John L

    2016-10-05

    This paper elucidates the means to control precisely the morphology of electrospun liquid crystal/polymer fibers formed by phase separation. The relative humidity, solution parameters (concentration, solvent), and the process parameter (feed rate) were varied systematically. We show that the morphology of the phase-separated liquid crystal can be continuously tuned from capsules to uniform fibers with systematic formation of beads-on-a-string structured fibers in the intermediate ranges. In all cases, the polymer forms a sheath around a liquid-crystal (LC) core. The width of the polymer sheath and the diameter of the LC core increase with increasing feed rates. This is similar to the results obtained by coaxial electrospinning. Because these fibers retain the responsive properties of liquid crystals and because of their large surface area, they have potential applications as thermo-, chemo-, and biosensors. Because the size and shape of the liquid-crystal domains will have a profound effect on the performance of the fibers, our ability to precisely control morphology will be crucial in developing these applications.

  16. Cellulose nanowhiskers and fiber alignment greatly improve mechanical properties of electrospun prolamin protein fibers.

    PubMed

    Wang, Yixiang; Chen, Lingyun

    2014-02-12

    Electrospun fibers from natural polymers must possess appropriate mechanical properties if they are to be functional in numerous applications. In this research, two convenient physical approaches were applied to reinforce the assembled hordein/zein electrospun nanofabrics: incorporation of surface-modified cellulose nanowhiskers (SCN) and fiber alignment. The mechanical properties and stability of the modified fibers were tested in relation to fiber morphology and structure as characterized by scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy, and Raman spectroscopy. SCN modified by quaternary ammonium salt were well-dispersed in hordein/zein networks, leading to fibers with significantly improved mechanical properties and water resistance. With the addition of 3 wt % SCN, the tensile strength and Young's modulus of hordein/zein fibers increased from 4.36 ± 0.29 to 7.79 ± 0.36 MPa and from 195.80 ± 13.02 to 396.64 ± 18.33 MPa, respectively, and the elongation at break was retained because of the formation of a percolating network of SCN. The alignment of electrospun fibers strengthened the hordein/zein nanofabrics in both tangential and normal directions to 17.26 ± 1.41 and 14.02 ± 0.74 MPa, respectively, by not only altering the piling up pattern, but also by promoting phase separation and improved interactions. When applying both of the reinforcing methods, the tensile strength of hordein/zein fibers was further enhanced to 21.99 ± 1.19 MPa, stronger than that of cancellous bones (5-10 MPa). All the reinforced fibers exhibited a reduced burst effect in phosphate-buffered saline (PBS) while releasing the incorporated bioactive molecule in a controlled manner. These physically reinforced prolamin protein fibers possessed significantly improved mechanical properties and may have potential to be used as tissue engineering scaffold materials or natural delivery systems for biomedical applications.

  17. 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.

  18. 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.

  19. Enhanced piezoresponse of electrospun PVDF mats with a touch of nickel chloride hexahydrate salt.

    PubMed

    Dhakras, Dipti; Borkar, Vivek; Ogale, Satishchandra; Jog, Jyoti

    2012-02-07

    PVDF nanofibers are prepared using electrospinning. The effect of addition of a hydrated salt, nickel chloride hexahydrate (NiCl(2)·6H(2)O), on the phase formation is examined. Addition of the hydrated salt (NC) is found to enhance the polar β phase by about 30%. The peak to peak piezo-voltage generated for PVDF NC is almost 0.762 V, a factor of 3 higher than that for PVDF. The fiber mats exhibit a significantly enhanced dynamic strain sensor response. The voltage generated per unit micro-strain developed during the free vibration test for PVDF was 0.119 mV whereas it was 0.548 mV for PVDF NC, exhibiting a non-linearly enhanced performance vis a vis the increase in the β phase component. This journal is © The Royal Society of Chemistry 2012

  20. Enhanced piezoresponse of electrospun PVDF mats with a touch of nickel chloride hexahydrate salt

    NASA Astrophysics Data System (ADS)

    Dhakras, Dipti; Borkar, Vivek; Ogale, Satishchandra; Jog, Jyoti

    2012-01-01

    PVDF nanofibers are prepared using electrospinning. The effect of addition of a hydrated salt, nickel chloride hexahydrate (NiCl2.6H2O), on the phase formation is examined. Addition of the hydrated salt (NC) is found to enhance the polar β phase by about 30%. The peak to peak piezo-voltage generated for PVDF NC is almost 0.762 V, a factor of 3 higher than that for PVDF. The fiber mats exhibit a significantly enhanced dynamic strain sensor response. The voltage generated per unit micro-strain developed during the free vibration test for PVDF was 0.119 mV whereas it was 0.548 mV for PVDF NC, exhibiting a non-linearly enhanced performance vis a vis the increase in the β phase component.PVDF nanofibers are prepared using electrospinning. The effect of addition of a hydrated salt, nickel chloride hexahydrate (NiCl2.6H2O), on the phase formation is examined. Addition of the hydrated salt (NC) is found to enhance the polar β phase by about 30%. The peak to peak piezo-voltage generated for PVDF NC is almost 0.762 V, a factor of 3 higher than that for PVDF. The fiber mats exhibit a significantly enhanced dynamic strain sensor response. The voltage generated per unit micro-strain developed during the free vibration test for PVDF was 0.119 mV whereas it was 0.548 mV for PVDF NC, exhibiting a non-linearly enhanced performance vis a vis the increase in the β phase component. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr11841f

  1. Characterisation of internal morphologies in electrospun fibers by X-ray tomographic microscopy

    NASA Astrophysics Data System (ADS)

    Nygaard, Jens Vinge; Uyar, Tamer; Chen, Menglin; Cloetens, Peter; Kingshott, Peter; Besenbacher, Flemming

    2011-09-01

    Electrospun fabrics for use in, for example, tissue engineering, wound dressings, textiles, filters and membranes have attracted a lot of attention due to their morphological nanoscale architectures which enhance their physical properties. A thorough detailed internal morphological study has been performed on electrospun polystyrene (PS) fibers produced from dimethylformamide (DMF) solutions. Investigations by transmission electron microscopy (TEM) and thorough studies for the first time by synchrotron based X-ray tomographic microscopy (XTM) revealed that the individual electrospun PS fibers and beads have a graded density and in some cases even an internal porous structure.

  2. 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.

  3. 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

  4. 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

  5. Diameter-tuning of electrospun cellulose acetate fibers: a Box-Behnken design (BBD) study.

    PubMed

    Konwarh, Rocktotpal; Misra, Manjusri; Mohanty, Amar K; Karak, Niranjan

    2013-02-15

    This work focuses on the use of statistical approach in optimizing shape-size accord of electrospun cellulose acetate (CA) mats - an apt material for biomedical and industrial applications. Modulation of three processing parameters, namely potential difference, distance between tip-to-collector and feed rate led to myriad of fiber-morphology (beaded, bead free, branched and ribbon) with diverse size-spectrum. Response surface methodology using Box-Behnken design technique indicated significant linear and quadratic influence of the chosen parameters. Fibers with minimal diameter of ~139 nm (with a mean coherency co-efficient of 0.5192) were predicted for 30 kV (voltage), 15 cm (tip-to-collector distance) and 2 mL/h (feed rate). Reasonable agreement existed between the predicted R-squared value (0.9565) and adjusted R-squared value (0.9824) with similar observation for the experimental and model values over the entire factor space. The developed model may serve as a base model for understanding process - parametric influence on electrospinning CA and related polymers.

  6. Electrospun sol-gel fibers for fluorescence-based sensing

    NASA Astrophysics Data System (ADS)

    Memisevic, Jasenka; Riley, Lela; Grant, Sheila A.

    2009-05-01

    Fluorescence based biosensors have the ability to provide reliable pathogen detection. However, the performance could be improved by enhancing the effective surface area of the biosensor. We report on a new nanofibrous fluorescencebased biosensor, whereas a sol-gel platform mesh was constructed by utilizing electrospinning techniques. Furthermore, incorporating cetyltrimethylammonium bromide (CTAB) and conducting pore-forming techniques resulted in a high surface area material suitable for biosensor immobilization. The biosensor was designed to detect Helicobacter hepaticus bacterium by sandwiching the pathogen between two antibodies, one labeled with Alexa Fluor 546 fluorescent dye and the other with 20nm Au nanoparticles. In the presence of pathogen, the close proximity of Au nanoparticles quenched the Alexa Fluor fluorescence, suggesting that the electrospun fiber platforms are suitable for sensing H. Hepaticus. Additionally, sol-gel fibers used as biosensor platform have the added benefit of increased immobilization, as fluorescence intensity from immobilized biosensors is 8.5x106 cps higher on fibers than on a flat, non-porous substrate.

  7. 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

  8. 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)

    2017-01-01

    A method of manufacturing and/or using a scaffold assembly for stem cell culture and tissue engineering applications is disclosed. The scaffold at least partially mimics 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 that 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.

  9. 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.

  10. 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.

  11. Sliding Fibers: Slidable, Injectable, and Gel-like Electrospun Nanofibers as Versatile Cell Carriers.

    PubMed

    Lee, Slgirim; Yun, Seokhwan; Park, Kook In; Jang, Jae-Hyung

    2016-03-22

    Designing biomaterial systems that can mimic fibrous, natural extracellular matrix is crucial for enhancing the efficacy of various therapeutic tools. Herein, a smart technology of three-dimensional electrospun fibers that can be injected in a minimally invasive manner was developed. Open surgery is currently the only route of administration of conventional electrospun fibers into the body. Coordinating electrospun fibers with a lubricating hydrogel produced fibrous constructs referred to as slidable, injectable, and gel-like (SLIDING) fibers. These SLIDING fibers could pass smoothly through a catheter and fill any cavity while maintaining their fibrous morphology. Their injectable features were derived from their distinctive rheological characteristics, which were presumably caused by the combinatorial effects of mobile electrospun fibers and lubricating hydrogels. The resulting injectable fibers fostered a highly favorable environment for human neural stem cell (hNSC) proliferation and neurosphere formation within the fibrous structures without compromising hNSC viability. SLIDING fibers demonstrated superior performance as cell carriers in animal stroke models subjected to the middle cerebral artery occlusion (MCAO) stroke model. In this model, SLIDING fiber application extended the survival rate of administered hNSCs by blocking microglial infiltration at the early, acute inflammatory stage. The development of SLIDING fibers will increase the clinical significance of fiber-based scaffolds in many biomedical fields and will broaden their applicability.

  12. Interactions between Surfactants in Solution and Electrospun Protein Fibers: Effects on Release Behavior and Fiber Properties.

    PubMed

    Stephansen, Karen; García-Díaz, María; Jessen, Flemming; Chronakis, Ioannis S; Nielsen, Hanne M

    2016-03-07

    Intermolecular interaction phenomena occurring between endogenous compounds, such as proteins and bile salts, and electrospun compounds are so far unreported, despite the exposure of fibers to such biorelevant compounds when applied for biomedical purposes, e.g., tissue engineering, wound healing, and drug delivery. In the present study, we present a systematic investigation of how surfactants and proteins, as physiologically relevant components, interact with insulin-loaded fish sarcoplasmic protein (FSP) electrospun fibers (FSP-Ins fibers) in solution and thereby affect fiber properties such as accessible surface hydrophilicity, physical stability, and release characteristics of an encapsulated drug. Interactions between insulin-loaded protein fibers and five anionic surfactants (sodium taurocholate, sodium taurodeoxycholate, sodium glycocholate, sodium glycodeoxycholate, and sodium dodecyl sulfate), a cationic surfactant (benzalkonium chloride), and a neutral surfactant (Triton X-100) were studied. The anionic surfactants increased the insulin release in a concentration-dependent manner, whereas the neutral surfactant had no significant effect on the release. Interestingly, only minute amounts of insulin were released from the fibers when benzalkonium chloride was present. The FSP-Ins fibers appeared dense after incubation with this cationic surfactant, whereas high fiber porosity was observed after incubation with anionic or neutral surfactants. Contact angle measurements and staining with the hydrophobic dye 8-anilino-1-naphthalenesulfonic acid indicated that the FSP-Ins fibers were hydrophobic, and showed that the fiber surface properties were affected differently by the surfactants. Bovine serum albumin also affected insulin release in vitro, indicating that also proteins may affect the fiber performance in an in vivo setting.

  13. Electrospun fibers for drug delivery after spinal cord injury and the effects of drug incorporation on fiber properties

    PubMed Central

    Johnson, Christopher D.L.; D’Amato, Anthony R.; Gilbert, Ryan J.

    2016-01-01

    There is currently no cure for individuals with spinal cord injury (SCI). While many promising approaches are in clinical trials, the complexity of SCI limits several of these approaches from achieving complete functional recovery. Several different categories of biomaterials are being investigated for their ability to guide axonal regeneration, to deliver proteins or small molecules locally, or to improve the viability of transplanted stem cells. The purpose of this manuscript is to provide a brief overview of SCI, present the different categories of biomaterial scaffolds that direct and guide axonal regeneration, and then focus specifically on electrospun fiber guidance scaffolds. Much like other polymer guidance approaches, electrospun fibers can retain and deliver therapeutic drugs. The experimental section presents new data showing the incorporation of two therapeutic drugs into electrospun poly-L-lactic acid (PLLA) fibers. Two different concentrations of either riluzole or neurotrophin 3 (NT-3) were loaded into the electrospun fibers to examine the effect of drug concentration on the physical characteristics of the fibers (fiber alignment and fiber diameter). Overall, the drugs were successfully incorporated into the fibers and the release was related to the loading concentration. Fiber diameter decreased with the inclusion of the drug, and the decreased diameter was correlated with a decrease in fiber alignment. Subsequently, the manuscript includes considerations for successful incorporation of a therapeutic drug without changing the physical properties of the fibers. PMID:27701153

  14. 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

  15. 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

  16. Tunable Engineered Skin Mechanics via Coaxial Electrospun Fiber Core Diameter

    PubMed Central

    Blackstone, Britani Nicole; Drexler, Jason William

    2014-01-01

    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. PMID:24712409

  17. 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

    2015-08-05

    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.

  18. 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.

  19. Preparation and characterization of a novel electrospun spider silk fibroin/poly(D,L-lactide) composite fiber.

    PubMed

    Zhou, Shaobing; Peng, Hongsen; Yu, Xiongjun; Zheng, Xiaotong; Cui, Wenguo; Zhang, Zairong; Li, Xiaohong; Wang, Jianxin; Weng, Jie; Jia, Wenxiang; Li, Fei

    2008-09-11

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

  20. Post-processing optimization of electrospun submicron poly(3-hydroxybutyrate) fibers to obtain continuous films of interest in food packaging applications.

    PubMed

    Cherpinski, Adriane; Torres-Giner, Sergio; Cabedo, Luis; Lagaron, Jose M

    2017-10-01

    Polyhydroxyalkanoates (PHAs) are one of the most researched family of biodegradable polymers based on renewable materials due to their thermoplastic nature and moisture resistance. The present study was targeted to investigate the preparation and characterization of poly(3-hydroxybutyrate) (PHB) films obtained through the electrospinning technique. To convert them into continuous films and then to increase their application interest in packaging, the electrospun fiber mats were subsequently post-processed by different physical treatments. Thus, the effect of annealing time and cooling method on morphology, molecular order, thermal, optical, mechanical, and barrier properties of the electrospun submicron PHB fibers was studied. Annealing at 160°C, well below the homopolyester melting point, was found to be the minimum temperature at which homogeneous transparent films were produced. The film samples that were cooled slowly after annealing showed the lowest permeability to oxygen, water vapor, and limonene. The optimally post-processed electrospun PHB fibers exhibited similar rigidity to conventional compression-molded PHA films, but with enhanced elongation at break and toughness. Films made by this electrospinning technique have many potential applications, such as in the design of barrier layers, adhesive interlayers, and coatings for fiber- and plastic-based food packaging materials.

  1. Electro-Spun Fine Fibers of Shape Memory Polymer Used as an Engineering Part

    DTIC Science & Technology

    2010-01-28

    control the experimental condition, it was difficult to fabricate the same diameter fibers . However, it was repeatedly confirmed, this paper mesh...fine fibers . By the use of electrospinning , for example, a two-dimensional filter with superior functionality can be easily fabricated. However...individually fabricating fibers is a difficult task for the electrospinning technology, since electro-spun fibers are inevitably entangled and stick

  2. In-syringe dispersive solid phase extraction: a novel format for electrospun fiber based microextraction.

    PubMed

    Zhu, Gang-Tian; He, Xiao-Mei; Cai, Bao-Dong; Wang, Han; Ding, Jun; Yuan, Bi-Feng; Feng, Yu-Qi

    2014-12-07

    A novel in-syringe dispersive solid phase extraction (dSPE) system using electrospun silica fibers as adsorbents has been developed in the current work. A few milligrams of electrospun silica fibers were incubated in sample solution in the barrel of a syringe for microextraction assisted by vortex. Due to the benefit of dispersion and the high mass transfer rate of the sub-microscale electrospun silica fibers, the extraction equilibrium was achieved in a very short time (less than 1 min). Moreover, thanks to the long fibrous properties of electrospun fibers, the separation of the adsorbent from sample solution was easily achieved by pushing out the sample solution which therefore simplified the sample pretreatment procedure. Besides, the analytical throughput was largely increased by using a multi-syringe plate to perform the extraction experiment. The performance of the in-syringe dSPE device was evaluated by extraction of endogenous cytokinins from plant tissue samples based on the hydrophilic interaction. Six endogenous cytokinins in 20 mg of Oryza sativa L. (O. sativa) leaves were successfully determined under optimized conditions using in-syringe dSPE combined with liquid chromatography-mass spectrometry analysis. The results demonstrated that the in-syringe dSPE method was a rapid and high-throughput strategy for the extraction of target compounds, which has great potential in microscale sample pretreatment using electrospun fibers.

  3. Electrospun zein fibers using glyoxal as the cross-linking reagent

    USDA-ARS?s Scientific Manuscript database

    Glyoxal has been used to provide zein electrospun fibers that are resistant to dissolution by known zein solvents. Durable fibers with diameters between 0.2 and 0.7 micrometers could be produced. The reaction between zein and glyoxal was carried out in acetic acid at temperatures between 25 and 60...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  5. Cytocompatible cross-linking of electrospun zein fibers for the development of water-stable tissue engineering scaffolds.

    PubMed

    Jiang, Qiuran; Reddy, Narendra; Yang, Yiqi

    2010-10-01

    This paper reports a new method of cross-linking electrospun zein fibers using citric acid as a non-toxic cross-linker to enhance the water stability and cytocompatibility of zein fibers for tissue engineering and other medical applications. The electrospun structure has many advantages over other types of structures and protein-based biomaterials possess unique properties preferred for tissue engineering and other medical applications. However, ultrafine fiber matrices developed from proteins have poor mechanical properties and morphological stability in the aqueous environments required for medical applications. Efforts have been made to improve the water stability of electrospun protein scaffolds using cross-linking and other approaches, but the current methods have major limitations, such as cytotoxicity and low efficiency. In this research electrospun zein fibers were cross-linked with citric acid without using any toxic catalysts. The stability of the cross-linked fibers in phosphate-buffered saline and their ability to support the attachment, spreading and proliferation of mouse fibroblast cells were studied. The cross-linked electrospun fibers retained their ultrafine fibrous structure even after immersion in PBS at 37 degrees C for up to 15 days. Citric acid cross-linked electrospun zein scaffolds showed better attachment, spreading and proliferation of fibroblast cells than uncross-linked electrospun zein fibers, cross-linked zein films and electrospun polylactide fibers.

  6. 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

  7. Morphology, drug release, antibacterial, cell proliferation, and histology studies of chamomile-loaded wound dressing mats based on electrospun nanofibrous poly(ɛ-caprolactone)/polystyrene blends.

    PubMed

    Motealleh, Behrooz; Zahedi, Payam; Rezaeian, Iraj; Moghimi, Morvarid; Abdolghaffari, Amir Hossein; Zarandi, Mohammad Amin

    2014-07-01

    For the first time, it has been tried to achieve optimum conditions for electrospun poly(ε-caprolactone)/polystyrene (PCL/PS) nanofibrous samples as active wound dressings containing chamomile via D-optimal design approach. In this work, systematic in vitro and in vivo studies were carried out by drug release rate, antibacterial and antifungal evaluations, cell culture, and rat wound model along with histology observation. The optimized samples were prepared under the following electrospinning conditions: PCL/PS ratio (65/35), PCL concentration 9%(w/v), PS concentration 14%(w/v), distance between the syringe needle tip and the collector 15.5 cm, applied voltage 18 kV, and solution flow rate 0.46 mL h(-1) . The FE-SEM micrographs showed electrospun PCL/PS (65/35) nanofibrous sample containing 15% chamomile had a minimum average diameter (∼175 nm) compared to the neat samples (∼268 nm). The drug released resulted in a gradual and high amount of chamomile from the optimized PCL/PS nanofibrous sample (∼70%) in respect to PCL and PS nanofibers after 48 h. This claim was also confirmed by antibacterial and antifungal evaluations in which an inhibitory zone with a diameter of about 7.6 mm was formed. The rat wound model results also indicated that the samples loaded with 15% chamomile extract were remarkably capable to heal the wounds up to 99 ± 0.5% after 14 days post-treatment periods. The adhesion of mesenchymal stem cells and their viability on the optimized samples were confirmed by MTT analysis. Also, the electrospun nanofibrous mats based on PCL/PS (65/35) showed a high efficiency in the wound closure and healing process compared to the reference sample, PCL/PS nanofibers without chamomile. Finally, the histology analysis revealed that the formation of epithelial tissues, the lack of necrosis and collagen fibers accumulation in the dermis tissues for the above optimized samples.

  8. Enhancement of the in-plane shear properties of carbon fiber composites containing carbon nanotube mats

    NASA Astrophysics Data System (ADS)

    Kim, Hansang

    2015-01-01

    The in-plane shear property of carbon fiber laminates is one of the most important structural features of aerospace and marine structures. Fiber-matrix debonding caused by in-plane shear loading is the major failure mode of carbon fiber composites because of the stress concentration at the interfaces. In this study, carbon nanotube mats (CNT mat) were incorporated in two different types of carbon fiber composites. For the case of woven fabric composites, mechanical interlocking between the CNTs and the carbon fibers increased resistance to shear failure. However, not much improvement was observed for the prepreg composites as a result of incorporation of the CNT mats. The reinforcement mechanism of the CNT mat layer was investigated by a fractographic study using scanning electron microscopy. In addition, the CNT mat was functionalized by three different methods and the effectiveness of the functionalization methods was determined and the most appropriate functionalization method for the CNT mat was air oxidation.

  9. Salicylic acid-derived poly(anhydride-ester) electrospun fibers designed for regenerating the peripheral nervous system

    PubMed Central

    Griffin, Jeremy; Delgado-Rivera, Roberto; Meiners, Sally; Uhrich, Kathryn E.

    2011-01-01

    Continuous biomaterial advances and the regenerating potential of the adult human peripheral nervous system offer great promise for restoring full function to innervated tissue following traumatic injury via synthetic nerve guidance conduits. To most effectively facilitate nerve regeneration, a tissue engineering scaffold within a conduit must be similar to the linear microenvironment of the healthy nerve. To mimic the native nerve structure, aligned poly(lactic-co-glycolic acid)/bioactive polyanhydride fibrous substrates were fabricated through optimized electrospinning parameters with diameters of 600 ± 200 nm. Scanning electron microscopy images show fibers with a high degree of alignment. Schwann cells and dissociated rat dorsal root ganglia demonstrated elongated and healthy proliferation in a direction parallel to orientated electrospun fibers with significantly longer Schwann cell process length and neurite outgrowth when compared to randomly orientated fibers. Results suggest that an aligned polyanhydride fiber mat holds tremendous promise as a supplement scaffold for the interior of a degradable polymer nerve guidance conduit. Bioactive salicylic acid based polyanhydride fibers are not limited to nerve regeneration and offer exciting promise for a wide variety of biomedical applications. PMID:21442724

  10. 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. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. 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.

  12. Reclamation of skid roads with fiber mats and native vegetation: effects on erosion

    Treesearch

    shawn T. Grushecky; David w. McGill; William Grafton; John Edwards; Lisa Tager

    2007-01-01

    A research study was established to test the effectiveness of fiber mats and native seed mixtures in reducing soil erosion from newly-constructed skid roads in the Elk River Watershed in central West Virginia. Twelve road sections of equal grade were paired with a randomly-selected section receiving a fiber mat and native grass seed while the other road section was not...

  13. Non-woven fibrous materials with antibacterial properties prepared by tailored attachment of quaternized chitosan to electrospun mats from maleic anhydride copolymer.

    PubMed

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

    2012-01-01

    In order to impart antibacterial properties to microfibrous electrospun materials from styrene/maleic anhydride copolymers, quaternized chitosan derivatives (QCh) containing alkyl substituents of different chain lengths are covalently attached to the mats. A complete inhibition of the growth of bacteria, S. aureus (Gram-positive) and E. coli (Gram-negative), for a contact time of 30–120 min or a decrease of the bacterial titer by 2–3 log units is observed depending on the quaternization degree, the chain length of the alkyl substituent, and the molar mass of QCh. The modified mats are also effective in suppressing the adhesion of pathogenic S. aureus bacteria.

  14. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2016-12-01

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

  16. Fabrication of Sustained-release CA-PU Coaxial Electrospun Fiber Membranes for Plant Grafting Application.

    PubMed

    Guo, Zhongfu; Tang, Guosheng; Zhou, Yonghong; Shuwu, Liu; Hou, Haoqing; Chen, Zhenyu; Chen, Jinhui; Hu, Chunhong; Wang, Fei; De Smedt, Stefaan C; Xiong, Ranhua; Huang, Chaobo

    2017-08-01

    Plant grafting is a well-known activity in orchards, greenhouses and vineyards gardens. However, low survival rate still limits the promotion of grafting and breeding of improved varieties. We report on polymeric fibers, obtained through coaxial electrospun, as carriers for the sustained release of drugs to heal wounds in plants. The CA-PU co-electrospun fibers show a rather uniform diameter, a smooth and hydrophilic surface. As long as 10days of sustained drugs release meets with the physiological requirement of plant grafting. The callus toxicity test shows that the CA-PU fibers are not toxic for plant cells. We show that loading the core of CA-PU fibers with 6-Benzylaminopurine (6-BA), a first-generation synthetic cytokinin that elicits plant growth and development, results in fibers that can efficiently promote the healing of plant wounds, thereby significantly improving the grafting survival rate. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. 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

  18. 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.

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

    PubMed

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

    2015-09-21

    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. Preparation of PCL/silk fibroin/collagen electrospun fiber for urethral reconstruction.

    PubMed

    Wei, Gaijie; Li, Chao; Fu, Qiang; Xu, Yuemin; Li, Hongbin

    2015-01-01

    To prepare polycaprolactone (PCL)/silk fibroin/collagen electrospun nanofiber scaffold and test its effects on growth and proliferation of oral mucosal epithelial cells. Regenerated silk fibroin film, water-soluble collagen powder, and PCL, at mass ratios of 1:1:4, 1:1:8, and 1:1:10, were dissolved in hexafluoroisopropanol, and electrostatic spinning method was adopted to prepare PCL/silk fibroin/collagen electrospun nanofiber scaffold. In vitro cultured oral mucosal epithelial cells were inoculated on the material surface, MTT assay and scanning electron microscopy were adopted to study the growth and proliferation of oral mucosal epithelial cells on the material surface, and cell compatibility of PCL/silk fibroin/collagen electrospun nanofiber was evaluated. The result of MTT assay showed that oral mucosal epithelial cells were growing well on the PCL/silk fibroin/collagen electrospun nanofiber scaffold. Scanning electron microscopy showed that the prepared electrospun fiber was uniform in diameter and presented an interconnected porous net structure, and oral mucosal epithelial cells had a good growth form on the surface of the modified material. PCL/silk fibroin/collagen electrospun nanofiber scaffold has appropriate pore size and porosity, is suitable for the growth of oral mucosal epithelial cells, has good cell compatibility, and is a good scaffold for tissue engineering urethral reconstruction.

  1. Long-term antimicrobial effect of nisin released from electrospun triaxial fiber membranes.

    PubMed

    Han, Daewoo; Sherman, Shalli; Filocamo, Shaun; Steckl, Andrew J

    2017-02-16

    Electrospun membranes encapsulating nisin in the core of multi-layer coaxial fibers, with a hydrophobic PCL intermediate layer and a hygroscopic cellulose acetate sheath, have been demonstrated to provide long-term antimicrobial activity combined with a hygroscopic outer layer. Antimicrobial performance has been evaluated using modified versions of the antimicrobial textile test AATCC 100 and AATCC 147 against Staphylococcus aureus. The AATCC 147 tests indicate that antimicrobial activity persists up to 7days. The quantitative analysis from the AATCC 100 test indicates that tri-layer coaxial ("triaxial") electrospun fiber membranes provide >99.99% bacteria kill (4logkill) for up to five days. This indicates that the nisin-incorporated triaxial fibers have excellent biocidal activities for up to 5days and then provide biostatic activity for 2 or more days. Compared with other types of electrospun membranes, such as core-sheath coaxial ("coaxial") and single homogenous fibers, triaxial fiber membranes provided more robust and more sustained antimicrobial activity. Single fibers with nisin showed relatively weak activity and only for one day. Coaxial fiber membranes exhibited antimicrobial activity for a long period, but their biocidal activity was much weaker than that of triaxial fiber membranes, and only exhibited >99% bacteria kill (2logkill) after 1day of exposure.

  2. Micropatterned coculture of vascular endothelial and smooth muscle cells on layered electrospun fibrous mats toward blood vessel engineering.

    PubMed

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

    2015-06-01

    A major challenge in vascular engineering is the establishment of proper microenvironment to guide the spatial organization, growth, and extracellular matrix (ECM) productions of cells found in blood vessels. In the current study, micropatterned fibrous mats with distinct ridges and grooves of different width were created to load smooth muscle cells (SMCs), which were assembled by stacking on vascular endothelial cell (EC)-loaded flat fibrous mats to mimic the in vivo-like organized structure of blood vessels. SMCs were mainly distributed in the ridges, and aligned fibers in the patterned regions led to the formation of elongated cell bodies, intense actin filaments, and expressions of collagen I and α-smooth muscle actin in a parallel direction with fibers. ECs spread over the flat fibrous mats and expressed collagen IV and laminin with a cobblestone-like feature. A z-stack scanning of fluorescently stained fibrous mats indicated that SMCs effectively infiltrated into fibrous scaffolds at the depth of around 200 μm. Compared with SMCs cultured alone, the coculture with ECs enhanced the proliferation, infiltration, and cytoskeleton elongation of SMCs on patterned fibrous mats. Although the coculture of SMCs made no significant difference in the EC growth, the coculture system on patterned fibrous scaffolds promoted ECM productions of both ECs and SMCs. Thus, this patterned fibrous configuration not only offers a promising technology in the design of tissue engineering scaffolds to construct blood vessels with durable mechanical properties, but also provides a platform for patterned coculture to investigate cell-matrix and cell-cell interactions in highly organized tissues. © 2014 Wiley Periodicals, Inc.

  3. 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

    2016-02-05

    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.

  4. 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.

  5. 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.

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

    USDA-ARS?s Scientific Manuscript database

    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...

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

    USDA-ARS?s Scientific Manuscript database

    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...

  8. Electrospun zein fibers using glyoxal or formaldehyde as the cross-linking reagent

    USDA-ARS?s Scientific Manuscript database

    Glyoxal or formaldehyde was used as a cross-linking reagent for zein (corn protein) to provide electrospun fibers with improved physical properties and solvent resistance. These reagents were used between 2 and 6%. The cross-linking reaction was carried out in acetic acid for various lengths of ti...

  9. 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.

  10. 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.

  11. Electrospun nanofibrous mats containing quaternized chitosan and polylactide with in vitro antitumor activity against HeLa cells.

    PubMed

    Ignatova, Milena G; Manolova, Nevena E; Toshkova, Reneta A; Rashkov, Iliya B; Gardeva, Elena G; Yossifova, Lilia S; Alexandrov, Marin T

    2010-06-14

    Nanofibrous materials containing the antitumor drug doxorubicin hydrochloride (DOX) were easily prepared using a one-step method by electrospinning of DOX/poly(L-lactide-co-D,L-lactide) (coPLA) and DOX/quaternized chitosan (QCh)/coPLA solutions. The pristine and DOX-containing mats were characterized by ATR-FTIR and X-ray photoelectron spectroscopy (XPS). The release rate of DOX from the prepared fibers increased with the increase in DOX content. The DOX release process was diffusion-controlled. MTT cell viability studies revealed that incorporation of DOX and QCh in the nanofibrous mats led to a significant reduction in the HeLa cells viability. It was found, that the antitumor efficacy of the DOX-containing mats at 6 h was higher than that of the free DOX. SEM, TEM, and fluorescence microscopic observations confirmed that the antitumor effect of QCh-based and DOX-containing fibrous mats was mainly due to induction of apoptosis in the HeLa cells.

  12. 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.

  13. Fluorescent Strips of Electrospun Fibers for Ratiometric Sensing of Serum Heparin and Urine Trypsin.

    PubMed

    Zhao, Long; Wang, Tao; Wu, Qiang; Liu, Yuan; Chen, Zhoujiang; Li, Xiaohong

    2017-02-01

    "Turn-on" or "turn-off" probes remain challenges in the establishment of sensitive, easily operated, and reliable methods for in situ monitoring bioactive substances. In the current study, electrospun fibrous strips are designed to provide straightforward observations of ratiometric color changes with the naked eye in the presence of serum heparin or urine trypsin. A tetraphenylethene (TPE) derivative is constructed and along with phloxine B is grafted on fibers, followed by protamine adsorption to induce static quenching of phloxine B and aggregation-induced emission of the TPE derivative. The presence of heparin or trypsin removes protamine to restore the fluorescence of phloxine B at 574 nm (I574) and relieve the emission of the TPE derivative at 472 nm (I472). The grafting densities of phloxine B and the TPE derivative are essential to achieve the optimal fluorescence-intensity ratio of I574/I472 for the ratiometric detection of heparin and trypsin. Under illumination by an ultraviolet lamp, the fibrous mats turn from cyan to green in the presence of heparin at 0.4 U/mL and to a bright yellow at 0.8 U/mL, which is feasible in sensing serum heparin levels during postoperative and long-term care of patients after cardiovascular surgery. The protamine digestion results in similar color transitions with increasing trypsin levels up to 8 μg/mL, indicating the potential for monitoring urine trypsin levels of pancreas transplant patients. The color strips based on the ratiometric fluorescent response indicate advantages in lowering the detection limit and improving the accuracy and reproducibility, bearing great potential for a real-time and naked-eye detection of bioactive substances as self-test devices.

  14. Computational predictions of the tensile properties of electrospun fiber meshes: effect of fiber diameter and fiber orientation

    PubMed Central

    Stylianopoulos, Triantafyllos; Bashur, Chris A.; Goldstein, Aaron S.; Guelcher, Scott A.; Barocas, Victor H.

    2008-01-01

    The mechanical properties of biomaterial scaffolds are crucial for their efficacy in tissue engineering and regenerative medicine. At the microscopic scale, the scaffold must be sufficiently rigid to support cell adhesion, spreading, and normal extracellular matrix deposition. Concurrently, at the macroscopic scale the scaffold must have mechanical properties that closely match those of the target tissue. The achievement of both goals may be possible by careful control of the scaffold architecture. Recently, electrospinning has emerged as an attractive means to form fused fiber scaffolds for tissue engineering. The diameter and relative orientation of fibers affect cell behavior, but their impact on the tensile properties of the scaffolds has not been rigorously characterized. To examine the structure-property relationship, electrospun meshes were made from a polyurethane elastomer with different fiber diameters and orientations and mechanically tested to determine the dependence of the elastic modulus on the mesh architecture. Concurrently, a multiscale modeling strategy developed for type I collagen networks was employed to predict the mechanical behavior of the polyurethane meshes. Experimentally, the measured elastic modulus of the meshes varied from 0.56 to 3.0 MPa depending on fiber diameter and the degree of fiber alignment. Model predictions for tensile loading parallel to fiber orientation agreed well with experimental measurements for a wide range of conditions when a fitted fiber modulus of 18 MPa was used. Although the model predictions were less accurate in transverse loading of anisotropic samples, these results indicate that computational modeling can assist in design of electrospun artificial tissue scaffolds. PMID:19627797

  15. 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.

  16. Incorporation of glass-reinforced hydroxyapatite microparticles into poly(lactic acid) electrospun fibre mats for biomedical applications.

    PubMed

    Santos, Daniel; Correia, Cristina O; Silva, Dina M; Gomes, Pedro S; Fernandes, Maria H; Santos, José D; Sencadas, Vitor

    2017-06-01

    Tissue engineering is constantly evolving towards novel materials that mimic the properties of the replaced injured tissue or organ. A hybrid electrospun membrane of electroactive poly(l-acid lactic) (PLLA) polymer with glass reinforced hydroxyapatite (Bonelike®) microparticles placed among the polymer fibres in a morphology like "islands in the sea" was processed. The incorporation of 60 to 80wt% Bonelike® bone grafts granules with ≤150μm into the polymer solution lead to an amorphous polymeric fibre membranes, and a decrease of the average polymer fibre diameter from 550±150nm for neat PLA down to 440±170nm for the hybrid composite. The presence of Bonelike® in the polymer mats reduced the activation energy for thermal degradation from 134kJ·mol(-1), obtained for the neat PLLA membranes down to 71kJ·mol(-1), calculated for the hybrid composite membranes. In vitro cell culture results suggest that the developed processing method does not induce cytotoxic effects in MG 63 osteoblastic cells, and creates an environment that enhances cell proliferation, when compared to the neat PLLA membrane. The simplicity and scalability of the processing method suggests a large application potential of this novel hybrid polymer-microparticles fibre membranes for bone regenerative medicine. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Hierarchical composite polyaniline-(electrospun polystyrene) fibers applied to heavy metal remediation.

    PubMed

    Alcaraz-Espinoza, José J; Chávez-Guajardo, Alicia E; Medina-Llamas, Juan C; Andrade, César A S; de Melo, Celso P

    2015-04-08

    We describe the in situ preparation of a multipurpose hierarchical polyaniline-polystyrene (PANI-PS) composite based in the chemical polymerization of PANI on nonwoven (NW) electrospun PS mats. We performed a detailed study of the properties of these materials to select the best strategies to incorporate PANI chains into pristine NW PS mats without compromising the original porosity and mechanical flexibility of the matrices. The resulting composites presented nanostructured PANI chains highly dispersed in the interior of the NW PS mat and showed good electrical properties and surface-wetting characteristics that could be easily controlled. In particular, we show that these NW PANI-PS mats exhibit interesting properties in their interaction with heavy metal ions. For instance, their high adsorption capacities toward dispersed Hg(II), Cd(II), Pb(II), Cr(VI), and Cu(II) ions make them promising materials for water remediation, by providing a simple manner of collecting and removing these metals from aqueous systems. In fact, the NW electrospun mats here presented do not suffer from the usual limitations found in materials commonly employed as adsorbents, such as a tendency to agglomerate or accumulate in the environment because of difficulties of properly recovering them after use. To better understand the nature of each pairwise metal-PANI interaction, we performed a thorough investigation of the optical and electrical changes induced by the metal adsorption in the NW PANI-PS mats. As a consequence of their interaction with the metal ions, the visual aspect of the mats change, a fact more evident in the case of Cr(VI) removal, when the matrices vary their color from green to purple. These changes are related to the variation of the oxidation state of the PANI chains: as the ion metals are progressively adsorbed into the mat, they promote the conversion in varying degrees of the PANI chains from salt emeraldine to the pernigraniline form, and the mats become more

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. Fiber diameters control osteoblastic cell migration and differentiation in electrospun gelatin.

    PubMed

    Sisson, Kristin; Zhang, Chu; Farach-Carson, Mary C; Chase, D Bruce; Rabolt, John F

    2010-09-15

    Defined electrospinning conditions were used to create scaffolds with different fiber diameters to investigate their interactions with osteoblastic MG63 cells. Nonwoven gelatin scaffolds were electrospun with varied fiber diameters to investigate the effect of fiber size and resultant porosity on cell proliferation, viability, migration, and differentiation. The low toxicity solvent acetic acid:ethyl acetate:water ratio and gelatin concentrations were optimized to create small and large diameter fibers. The fiber diameters obtained by this procedure were 110 +/- 40 nm for the small and 600 +/- 110 nm for the large fibers. Cell viability assays showed that MG63 cells grew similarly on both fibers at the early time point (day 3) but preferred the scaffold with large diameter fibers by the later time points (day 5 and day 7). Confocal microscopic imaging showed that MG63 cells migrated poorly (maximum depth of 18 microm) into the scaffold of small diameter fibers, but readily penetrated (maximum depth of 50 microm) into the scaffold of large diameter fibers. Alkaline phosphatase (ALP) assays showed that MG63 cells differentiated on scaffolds made from both diameter fibers. In longer term experiments, MG63 cells differentiated to a greater extent on scaffolds made from small diameter fibers compared to large diameter fibers at days 3 and 7, but the ALP levels were the same for both diameter fibers by day 14. These results indicate that cells can perceive differences in the diameter and resultant pore size of electrospun gelatin fibers and that they process this information to alter their behavior.

  4. 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.

  5. 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.

  6. Synthesis, characterization, and antimicrobial properties of novel double layer nanocomposite electrospun fibers for wound dressing applications

    PubMed Central

    Hassiba, Alaa J; El Zowalaty, Mohamed E; Webster, Thomas J; Abdullah, Aboubakr M; Nasrallah, Gheyath K; Khalil, Khalil Abdelrazek; Luyt, Adriaan S; Elzatahry, Ahmed A

    2017-01-01

    Herein, novel hybrid nanomaterials were developed for wound dressing applications with antimicrobial properties. Electrospinning was used to fabricate a double layer nanocomposite nanofibrous mat consisting of an upper layer of poly(vinyl alcohol) and chitosan loaded with silver nanoparticles (AgNPs) and a lower layer of polyethylene oxide (PEO) or polyvinylpyrrolidone (PVP) nanofibers loaded with chlorhexidine (as an antiseptic). The top layer containing AgNPs, whose purpose was to protect the wound site against environmental germ invasion, was prepared by reducing silver nitrate to its nanoparticulate form through interaction with chitosan. The lower layer, which would be in direct contact with the injured site, contained the antibiotic drug needed to avoid wound infections which would otherwise interfere with the healing process. Initially, the upper layer was electrospun, followed sequentially by electrospinning the second layer, creating a bilayer nanofibrous mat. The morphology of the nanofibrous mats was studied by scanning electron microscopy and transmission electron microscopy, showing successful nanofiber production. X-ray diffraction confirmed the reduction of silver nitrate to AgNPs. Fourier transform infrared spectroscopy showed a successful incorporation of the material used in the produced nanofibrous mats. Thermal studies carried out by thermogravimetric analysis indicated that the PVP–drug-loaded layer had the highest thermal stability in comparison to other fabricated nanofibrous mats. Antimicrobial activities of the as-synthesized nanofibrous mats against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Candida albicans were determined using disk diffusion method. The results indicated that the PEO–drug-loaded mat had the highest antibacterial activity, warranting further attention for numerous wound-healing applications. PMID:28356737

  7. Carbon Nanotube Mats and Fibers with Irradiation-Improved Mechanical Characteristics: A Theoretical Model

    NASA Astrophysics Data System (ADS)

    Åström, J. A.; Krasheninnikov, A. V.; Nordlund, K.

    2004-11-01

    We employ a theoretical model to calculate mechanical characteristics of macroscopic mats and fibers of single-walled carbon nanotubes. We further investigate irradiation-induced covalent bonds between nanotubes and their effects on the tensile strength of nanotube mats and fibers. We show that the stiffness and strength of the mats can be increased at least by an order of magnitude, and thus small-dose irradiation with energetic particles is a promising tool for making macroscopic nanotube materials with excellent mechanical characteristics.

  8. Nitric Oxide-Releasing Silica Nanoparticle-Doped Polyurethane Electrospun Fibers

    PubMed Central

    Koh, Ahyeon; Carpenter, Alexis W.; Slomberg, Danielle L.; Schoenfisch, Mark H.

    2013-01-01

    Electrospun polyurethane fibers doped with nitric oxide (NO)-releasing silica particles are presented as novel macromolecular scaffolds with prolonged NO-release and high porosity. Fiber diameter (119–614 nm) and mechanical strength (1.7–34.5 MPa of modulus) were varied by altering polyurethane type and concentration, as well as the NO-releasing particle composition, size, and concentration. The resulting NO-releasing electrospun nanofibers exhibited ~83% porosity with flexible plastic or elastomeric behavior. The use of N-diazeniumdiolate- or S-nitrosothiol-modified particles yielded scaffolds exhibiting a wide range of NO release totals and durations (7.5 nmol mg−1–0.12 μmol mg−1 and 7 h to 2 weeks, respectively). The application of NO-releasing porous materials as coating for subcutaneous implants may improve tissue biocompatibility by mitigating the foreign body response and promoting cell integration. PMID:23915047

  9. Creation of highly aligned electrospun poly-L-lactic acid fibers for nerve regeneration applications

    NASA Astrophysics Data System (ADS)

    Wang, Han Bing; Mullins, Michael E.; Cregg, Jared M.; Hurtado, Andres; Oudega, Martin; Trombley, Matthew T.; Gilbert, Ryan J.

    2009-02-01

    Aligned, electrospun polymer fibers have shown considerable promise in directing regenerating axons in vitro and in vivo. However, in several studies, final electrospinning parameters are presented for producing aligned fiber scaffolds, and alignment where minimal fiber crossing occurs is not achieved. Highly aligned species are necessary for neural tissue engineering applications to ensure that axonal extension occurs through a regenerating environment efficiently. Axonal outgrowth on fibers that deviate from the natural axis of growth may delay axonal extension from one end of a scaffold to the other. Therefore, producing aligned fiber scaffolds with little fiber crossing is essential. In this study, the contributions of four electrospinning parameters (collection disk rotation speed, needle size, needle tip shape and syringe pump flow rate) were investigated thoroughly with the goal of finding parameters to obtain highly aligned electrospun fibers made from poly-L-lactic acid (PLLA). Using an 8 wt% PLLA solution in chloroform, a collection disk rotation speed of 1000 revolutions per minute (rpm), a 22 gauge, sharp-tip needle and a syringe pump rate of 2 ml h-1 produced highly aligned fiber (1.2-1.6 µm in diameter) scaffolds verified using a fast Fourier transform and a fiber alignment quantification technique. Additionally, the application of an insulating sheath around the needle tip improved the rate of fiber deposition (electrospinning efficiency). Optimized scaffolds were then evaluated in vitro using embryonic stage nine (E9) chick dorsal root ganglia (DRGs) and rat Schwann cells (SCs). To demonstrate the importance of creating highly aligned scaffolds to direct neurite outgrowth, scaffolds were created that contained crossing fibers. Neurites on these scaffolds were directed down the axis of the aligned fibers, but neurites also grew along the crossed fibers. At times, these crossed fibers even stopped further axonal extension. Highly aligned PLLA fibers

  10. Aqueous Boron Removal by Using Electrospun Poly(vinyl alcohol) (PVA) Mats: A Combined Study of IR/Raman Spectroscopy and Computational Chemistry.

    PubMed

    Lee, Kwan Sik; Eom, Ki Heon; Lim, Jun-Heok; Ryu, Hyunwook; Kim, Suhan; Lee, Dong-Kyu; Won, Yong Sun

    2017-03-23

    We report the use of a novel and efficient method to remove aqueous boron by using electrospun, water-resistant poly(vinyl alcohol) (PVA) mats stabilized in methanol. The removal of the primary aqueous boron species as (B(OH)3), was accomplished by chemical adsorption in reactions with -OH (hydroxyl) groups on the PVA mat surface. The chemical adsorption of B(OH)3 was qualitatively confirmed by the analysis of IR and Raman spectra. The bands, corresponding to the molecular vibration modes of chemically bonded boron in PVA, were identified by using the frequency calculation from the computational chemistry for the first time. The adsorption capacities of PVA mats for aqueous boron were then quantitated at a low boron concentration (range: 0.0010 to 0.0025 g of aqueous boron per g of PVA mats) by the Carmine method. The PVA mats were prepared by a well-established electrospinning technique, which make these substrates promising potential candidates for use as boron-selective sorbent media in applications such as reverse osmosis desalination processes.

  11. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Electrospun polyurethane fibers for absorption of volatile organic compounds from air.

    PubMed

    Scholten, Elke; Bromberg, Lev; Rutledge, Gregory C; Hatton, T Alan

    2011-10-01

    Electrospun polyurethane fibers for removal of volatile organic compounds (VOC) from air with rapid VOC absorption and desorption have been developed. Polyurethanes based on 4,4-methylenebis(phenylisocyanate) (MDI) and aliphatic isophorone diisocyanate as the hard segments and butanediol and tetramethylene glycol as the soft segments were electrospun from their solutions in N,N-dimethylformamide to form micrometer-sized fibers. Although activated carbon possessed a many-fold higher surface area than the polyurethane fiber meshes, the sorption capacity of the polyurethane fibers was found to be similar to that of activated carbon specifically designed for vapor adsorption. Furthermore, in contrast to VOC sorption on activated carbon, where complete regeneration of the adsorbent was not possible, the polyurethane fibers demonstrated a completely reversible absorption and desorption, with desorption obtained by a simple purging with nitrogen at room temperature. The fibers possessed a high affinity toward toluene and chloroform, but aliphatic hexane lacked the necessary strong attractive interactions with the polyurethane chains and therefore was less strongly absorbed. The selectivity of the polyurethane fibers toward different vapors, along with the ease of regeneration, makes them attractive materials for VOC filtration. © 2011 American Chemical Society

  13. Electrospun Matrices for Pelvic Floor Repair: Effect of Fiber Diameter on Mechanical Properties and Cell Behavior.

    PubMed

    Vashaghian, Mahshid; Zandieh-Doulabi, Behrouz; Roovers, Jan-Paul; Smit, Theodoor Henri

    2016-12-01

    Electrospun matrices are proposed as an alternative for polypropylene meshes in reconstructive pelvic surgery. Here, we investigated the effect of fiber diameter on (1) the mechanical properties of electrospun poly (lactic-co-glycolic acid)-blended-poly(caprolactone) (PLGA/PCL) matrices; (2) cellular infiltration; and (3) the newly formed extracellular matrix (ECM) in vitro. We compared electrospun matrices with 1- and 8 μm fiber diameter and used nonporous PLGA/PCL films as controls. The 8-μm matrices were almost twice as stiff as the 1-μm matrices with 1.38 and 0.66 MPa, respectively. Matrices had the same ultimate tensile strength, but with 80% the 1-μm matrices were much more ductile than the 8-μm ones (18%). Cells infiltrated deeper into the matrices with larger pores, but cellular activity was comparable on both substrates. New ECM was deposited faster on the electrospun samples, but after 2 and 4 weeks the amount of collagen was comparable with that on nonporous films. The ECM deposited on the 1-μm matrices, and the nonporous film was about three times stiffer than the ECM found on the 8-μm matrices. Cell behavior in terms of myofibroblastic differentiation and remodeling was similar on the 1-μm matrices and nonporous films, in comparison to that on the 8-μm matrices. We conclude that electrospinning enhances the integration of host cells as compared with a nonporous film of the same material. The 1-μm matrices result in better mechanical behavior and qualitatively better matrix production than the 8-μm matrices, but with limited cellular infiltration. These data are useful for designing electrospun matrices for the pelvic floor.

  14. Controlled Deposition and Collection of Electro-spun Poly(ethylene oxide) Fibers

    DTIC Science & Technology

    2001-03-01

    261-272, 2001. 3. Reneker, D.H., and I. Chun, “Nanometer Diameter Fibres of Polymer, Produced by Electrospinning ,” Nanotechnology, Vol. 7, pp. 216...Bending Instability of Electrically Charged Liquid Jets of Polymer Solution in Electrospinning ,” Journal of Applied Physics, Vol. 87, pp. 4531–4547...2000. 16 11. Doshi, J., and D.H. Reneker, “ Electrospinning Process and Applications of Electrospun Fibers,” Journal of Electrostatics, Vol. 35, pp. 151

  15. Relative humidity effect on the preparation of porous electrospun polystyrene fibers.

    PubMed

    Park, Ju-Young; Lee, In-Hwa

    2010-05-01

    Porous polystyrene (PS) fibers were prepared by relative humidity control during electrospinning process. The relative humidity and solvent mixing ratio strongly affect the surface morphology and average diameter of electrospun PS fibers. In the circumstance of 30% relative humidity at MC/EtOH (90/10, v/v), pores did not form on the surface of polystyrene fibers. However, as the relative humidity increased to 60%, pores appeared on the fiber surface at the same composition of solvent. In comparison, solvent ratio of MC/EtOH (80/20, v/v) gave rather smooth surface of PS fibers. When the MC/EtOH ratio are 90/10 (v/v) and 80/20 (v/v), electrospun PS fibers with minimum average diameter of 5,211 nm (SD = 1,986) and 5,315 nm (SD = 1,039) were prepared. Surface area and average pore size are found to be 30.7 m2/g and 8.7 nm, respectively, with the relative humidity of 40%.

  16. Calcium Silicate/Chitosan-Coated Electrospun Poly (Lactic Acid) Fibers for Bone Tissue Engineering

    PubMed Central

    Su, Chu-Jung; Tu, Ming-Gene; Wei, Li-Ju; Hsu, Tuan-Ti; Kao, Chia-Tze; Chen, Tsui-Han; Huang, Tsui-Hsien

    2017-01-01

    Electrospinning technology allows fabrication of nano- or microfibrous fibers with inorganic and organic matrix and it is widely applied in bone tissue engineering as it allows precise control over the shapes and structures of the fibers. Natural bone has an ordered composition of organic fibers with dispersion of inorganic apatite among them. In this study, poly (lactic acid) (PLA) mats were fabricated with electrospinning and coated with chitosan (CH)/calcium silicate (CS) mixer. The microstructure, chemical component, and contact angle of CS/CH-PLA composites were analyzed by scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. In vitro, various CS/CH-coated PLA mats increased the formation of hydroxyapatite on the specimens’ surface when soaked in cell cultured medium. During culture, several biological characteristics of the human mesenchymal stem cells (hMSCs) cultured on CS/CH-PLA groups were promoted as compared to those on pure PLA mat. Increased secretion levels of Collagen I and fibronectin were observed in calcium silicate-powder content. Furthermore, with comparison to PLA mats without CS/CH, CS10 and CS15 mats markedly enhanced the proliferation of hMSCs and their osteogenesis properties, which was characterized by osteogenic-related gene expression. These results clearly demonstrated that the biodegradable and electroactive CS/CH-PLA composite mats are an ideal and suitable candidate for bone tissue engineering. PMID:28772861

  17. 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.

  18. Composite poly(vinyl alcohol)/poly(vinyl acetate) electrospun nanofibrous mats as a novel wound dressing matrix for controlled release of drugs

    PubMed Central

    Jannesari, Marziyeh; Varshosaz, Jaleh; Morshed, Mohammad; Zamani, Maedeh

    2011-01-01

    The aim of this study was to develop novel biomedicated nanofiber electrospun mats for controlled drug release, especially drug release directly to an injury site to accelerate wound healing. Nanofibers of poly(vinyl alcohol) (PVA), poly(vinyl acetate) (PVAc), and a 50:50 composite blend, loaded with ciprofloxacin HCl (CipHCl), were successfully prepared by an electrospinning technique for the first time. The morphology and average diameter of the electrospun nanofibers were investigated by scanning electron microscopy. X-ray diffraction studies indicated an amorphous distribution of the drug inside the nanofiber blend. Introducing the drug into polymeric solutions significantly decreased solution viscosities as well as nanofiber diameter. In vitro drug release evaluations showed that both the kind of polymer and the amount of drug loaded greatly affected the degree of swelling, weight loss, and initial burst and rate of drug release. Blending PVA and PVAc exhibited a useful and convenient method for electrospinning in order to control the rate and period of drug release in wound healing applications. Also, the thickness of the blend nanofiber mats strongly influenced the initial release and rate of drug release. PMID:21720511

  19. Composite poly(vinyl alcohol)/poly(vinyl acetate) electrospun nanofibrous mats as a novel wound dressing matrix for controlled release of drugs.

    PubMed

    Jannesari, Marziyeh; Varshosaz, Jaleh; Morshed, Mohammad; Zamani, Maedeh

    2011-01-01

    The aim of this study was to develop novel biomedicated nanofiber electrospun mats for controlled drug release, especially drug release directly to an injury site to accelerate wound healing. Nanofibers of poly(vinyl alcohol) (PVA), poly(vinyl acetate) (PVAc), and a 50:50 composite blend, loaded with ciprofloxacin HCl (CipHCl), were successfully prepared by an electrospinning technique for the first time. The morphology and average diameter of the electrospun nanofibers were investigated by scanning electron microscopy. X-ray diffraction studies indicated an amorphous distribution of the drug inside the nanofiber blend. Introducing the drug into polymeric solutions significantly decreased solution viscosities as well as nanofiber diameter. In vitro drug release evaluations showed that both the kind of polymer and the amount of drug loaded greatly affected the degree of swelling, weight loss, and initial burst and rate of drug release. Blending PVA and PVAc exhibited a useful and convenient method for electrospinning in order to control the rate and period of drug release in wound healing applications. Also, the thickness of the blend nanofiber mats strongly influenced the initial release and rate of drug release.

  20. Plasticized drug-loaded melt electrospun polymer mats: characterization, thermal degradation, and release kinetics.

    PubMed

    Balogh, Attila; Drávavölgyi, Gábor; Faragó, Kornél; Farkas, Attila; Vigh, Tamás; Sóti, Péter Lajos; Wagner, István; Madarász, János; Pataki, Hajnalka; Marosi, György; Nagy, Zsombor Kristóf

    2014-04-01

    Melt electrospinning (MES) was used to prepare fast dissolving fibrous drug delivery systems in the presence of plasticizers. This new method was found promising in the field of pharmaceutical formulation because it combines the advantages of melt extrusion and solvent-based electrospinning. Lowering of the process temperature was performed using plasticizers in order to avoid undesired thermal degradation. Carvedilol (CAR), a poorly water-soluble and thermal-sensitive model drug, was introduced into an amorphous methacrylate terpolymer matrix, Eudragit® E, suitable for fiber formation. Three plasticizers (triacetin, Tween® 80, and polyethylene glycol 1500) were tested, all of which lowered the process temperature effectively. Scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and Raman microspectrometry investigations showed that crystalline CAR turned into an amorphous form during processing and preserved it for longer time. In vitro dissolution studies revealed ultrafast drug dissolution of the fibrous samples. According to the HPLC impurity tests, the reduced stability of CAR under conditions applied without plasticizer could be avoided using plasticizers, whereas storage tests also indicated the importance of optimizing the process parameters during MES.

  1. The influence of fiber diameter of electrospun substrates on neural stem cell differentiation and proliferation.

    PubMed

    Christopherson, Gregory T; Song, Hongjun; Mao, Hai-Quan

    2009-02-01

    Neural stem/progenitor cells (NSCs) are capable of self-renewal and differentiation into all types of neural lineage under different biochemical and topographical cues. In this study, we cultured rat hippocampus-derived adult NSCs (rNSCs) on laminin-coated electrospun Polyethersulfone (PES) fiber meshes with average fiber diameters of 283+/-45 nm, 749+/-153 nm and 1452+/-312 nm; and demonstrated that fiber diameter of PES mesh significantly influences rNSC differentiation and proliferation. Under the differentiation condition (in the presence of 1 microM retinoic acid and 1% fetal bovine serum), rNSCs showed a 40% increase in oligodendrocyte differentiation on 283-nm fibers and 20% increase in neuronal differentiation on 749-nm fibers, in comparison to tissue culture polystyrene surface. SEM imaging revealed that cells stretched multi-directionally to follow underlying 283-nm fibers, but extended along a single fiber axis on larger fibers. When cultured on fiber meshes in serum free medium in the presence of 20 ng/mL of FGF-2, rNSCs showed lower proliferation and more rounded morphology compared to that cultured on laminin-coated 2D surface. As the fiber diameter decreased, higher degree of proliferation and cell spreading and lower degree of cell aggregation were observed. This collective evidence indicates fiber topography can play a vital role in regulating differentiation and proliferation of rNSCs in culture.

  2. 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

  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. Scale-dependent fiber kinematics of elastomeric electrospun scaffolds for soft tissue engineering

    PubMed Central

    Stella, John A.; Wagner, William R.; Sacks, Michael S.

    2013-01-01

    Electrospun poly(ester urethane)urea (PEUU) scaffolds contain complex multiscale hierarchical structures that work simultaneously to produce unique macrolevel mechanical behaviors. In this study, we focused on quantifying key multiscale scaffold structural features to elucidate the mechanisms by which these scaffolds function to emulate native tissue tensile behavior. Fiber alignment was modulated via increasing rotational velocity of the collecting mandrel, and the resultant specimens were imaged using SEM under controlled biaxial strain. From the SEM images, fiber splay, tortuosity, and diameter were quantified in the unstrained and deformed configurations. Results indicated that not only fiber alignment increased with mandrel velocity but also, paradoxically, tortuosity increased concurrently with mandrel velocity and was highly correlated with fiber orientation. At microlevel scales (1–10 μm), local scaffold deformation behavior was observed to be highly heterogeneous, while increasing the scale resulted in an increasingly homogenous strain field. From our comprehensive measurements, we determined that the transition scale from heterogenous to homogeneous-like behavior to be ~1 mm. Moreover, while electrospun PEUU scaffolds exhibit complex deformations at the microscale, the larger scale structural features of the fibrous network allow them to behave as long-fiber composites that deform in an affine-like manner. This study underscores the importance of understanding the structure–function relationships in elastomeric fibrous scaffolds, and in particular allowed us to link microscale deformations with mechanisms that allow them to successfully simulate soft tissue mechanical behavior. PMID:19753623

  5. Superfine powdered activated carbon incorporated into electrospun polystyrene fibers preserve adsorption capacity.

    PubMed

    Apul, Onur G; Hoogesteijn von Reitzenstein, Natalia; Schoepf, Jared; Ladner, David; Hristovski, Kiril D; Westerhoff, Paul

    2017-03-17

    A composite material consisted of superfine powdered activated carbon (SPAC) and fibrous polystyrene (PS) was fabricated for the first time by electrospinning. SPAC is produced by pulverizing powdered activated carbon. The diameter of SPAC (100-400nm) is more than one hundred times smaller than conventional powdered activated carbon, but it maintains the internal pore structure based on organic micropollutant adsorption isotherms and specific surface area measurements. Co-spinning SPAC into PS fibers increased specific surface area from 6m(2)/g to 43m(2)/g. Unlike metal oxide nanoparticles, which are non-accessible for sorption from solution, electrospinning with SPAC created porous fibers. Composite SPAC-PS electrospun fibers, containing only 10% SPAC, had 30% greater phenanthrene sorption compared against PS fibers alone. SPAC particles embedded within the polymer were either partially or fully incorporated, and the accessibility of terminal adsorption sites were conserved. Conserving the adsorptive functionality of SPAC particles in electrospun non-woven polymeric fiber scaffolding can enable their application in environmental applications such as drinking water treatment.

  6. Scale-dependent fiber kinematics of elastomeric electrospun scaffolds for soft tissue engineering.

    PubMed

    Stella, John A; Wagner, William R; Sacks, Michael S

    2010-06-01

    Electrospun poly(ester urethane)urea (PEUU) scaffolds contain complex multiscale hierarchical structures that work simultaneously to produce unique macrolevel mechanical behaviors. In this study, we focused on quantifying key multiscale scaffold structural features to elucidate the mechanisms by which these scaffolds function to emulate native tissue tensile behavior. Fiber alignment was modulated via increasing rotational velocity of the collecting mandrel, and the resultant specimens were imaged using SEM under controlled biaxial strain. From the SEM images, fiber splay, tortuosity, and diameter were quantified in the unstrained and deformed configurations. Results indicated that not only fiber alignment increased with mandrel velocity but also, paradoxically, tortuosity increased concurrently with mandrel velocity and was highly correlated with fiber orientation. At microlevel scales (1-10 mum), local scaffold deformation behavior was observed to be highly heterogeneous, while increasing the scale resulted in an increasingly homogenous strain field. From our comprehensive measurements, we determined that the transition scale from heterogenous to homogeneous-like behavior to be approximately 1 mm. Moreover, while electrospun PEUU scaffolds exhibit complex deformations at the microscale, the larger scale structural features of the fibrous network allow them to behave as long-fiber composites that deform in an affine-like manner. This study underscores the importance of understanding the structure-function relationships in elastomeric fibrous scaffolds, and in particular allowed us to link microscale deformations with mechanisms that allow them to successfully simulate soft tissue mechanical behavior.

  7. 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.

  8. Tensile mechanical properties and hydraulic permeabilities of electrospun cellulose acetate fiber meshes.

    PubMed

    Stylianopoulos, Triantafyllos; Kokonou, Maria; Michael, Stefanos; Tryfonos, Antonia; Rebholz, Claus; Odysseos, Andreani D; Doumanidis, Charalambos

    2012-11-01

    The mechanical properties and hydraulic permeabilities of biomaterial scaffolds play a crucial role in their efficacy as tissue engineering platforms, separation processors, and drug delivery vehicles. In this study, electrospun cellulose acetate fiber meshes of random orientations were created using four different concentrations, 10.0, 12.5, 15.0, and 17.5 wt % in acetone or ethyl acetate. The tensile mechanical properties and the hydraulic permeabilities of these meshes were measured, and a multiscale model was employed to predict their mechanical behavior. Experimentally, the elastic modulus ranged from 3.5 to 12.4 MPa depending on the polymer concentration and the solvent. Model predictions agreed well with the experimental measurements when a fitted single-fiber modulus of 123.3 MPa was used. The model also predicted that changes in fiber alignment may result in a 3.6-fold increase in the elastic modulus for moderately aligned meshes and a 8.5-fold increase for highly align meshes. Hydraulic permeabilities ranged from 1.4 x 10(-12) to 8.9 x 10(-12) m(2) depending on polymer concentration but not the choice of solvent. In conclusion, polymer concentration, fiber alignment, and solvent have significant impact on the mechanical and fluid transport properties of electrospun cellulose acetate fiber meshes.

  9. Efficacy of engineered FVIII-producing skeletal muscle enhanced by growth factor-releasing co-axial electrospun fibers.

    PubMed

    Liao, I-Chien; Leong, Kam W

    2011-02-01

    Co-axial electrospun fibers can offer both topographical and biochemical cues for tissue engineering applications. In this study, we demonstrate the sustained treatment of hemophilia through a non-viral, tissue engineering approach facilitated by growth factor-releasing co-axial electrospun fibers. FVIII-producing skeletal myotubes were first engineered on aligned electrospun fibers in vitro, followed by implantation in hemophilic mice with or without a layer of core-shell electrospun fibers designed to provide sustained delivery of angiogenic or lymphangiogenic growth factors, which serves to stimulate the lymphatic or vascular systems to enhance the FVIII transport from the implant site into systemic circulation. Upon subcutaneous implantation into hemophilic mice, the construct seamlessly integrated with the host tissue within one month, and specifically induced either vascular or lymphatic network infiltration in accordance with the growth factors released from the electrospun fibers. Engineered constructs that induced angiogenesis resulted in sustained elevation of plasma FVIII and significantly reduced blood coagulation time for at least 2-months. Biomaterials-assisted functional tissue engineering was shown in this study to offer protein replacement therapy for a genetic disorder such as hemophilia.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  11. Plateau-Rayleigh Instability Morphology Evolution (PRIME): From Electrospun Core-Shell Polymer Fibers to Polymer Microbowls.

    PubMed

    Chiu, Yu-Jing; Tseng, Hsiao-Fan; Lo, Yu-Ching; Wu, Bo-Hao; Chen, Jiun-Tai

    2017-03-01

    Electrospun core-shell fibers have great potentials in many areas, such as tissue engineering, drug delivery, and organic solar cells. Although many core-shell fibers have been prepared and studied, the morphology transformation of core-shell fibers have been rarely studied. In this work, the morphology evolution of electrospun core-shell polymer fibers driven by the Plateau-Rayleigh instability is investigated. Polystyrene/poly(methyl methacrylate) (PS/PMMA) core-shell fibers are first prepared by using blend solutions and a single axial electrospinning setup. After PS/PMMA core-shell fibers are annealed on a PS film, the fibers undulate and sink into the polymer film, forming core-shell hemispheres. The evolution process, which can be observed in situ by optical microscopy, is mainly driven by achieving lower surface and interfacial energies. The morphologies of the transformed structures can be confirmed by a selective removal technique, and polymer microbowls can be obtained.

  12. 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.

  13. Optical fiber ultrasound transmitter with electrospun carbon nanotube-polymer composite.

    PubMed

    Poduval, Radhika K; Noimark, Sacha; Colchester, Richard J; Macdonald, Thomas J; Parkin, Ivan P; Desjardins, Adrien E; Papakonstantinou, Ioannis

    2017-05-29

    All-optical ultrasound transducers are promising for imaging applications in minimally invasive surgery. In these devices, ultrasound is transmitted and received through laser modulation, and they can be readily miniaturized using optical fibers for light delivery. Here, we report optical ultrasound transmitters fabricated by electrospinning an absorbing polymer composite directly onto the end-face of optical fibers. The composite coating consisting of an aqueous dispersion of multi-walled carbon nanotubes (MWCNTs) in polyvinyl alcohol was directly electrospun onto the cleaved surface of a multimode optical fiber and subsequently dip-coated with polydimethylsiloxane (PDMS). This formed a uniform nanofibrous absorbing mesh over the optical fiber end-face wherein the constituent MWCNTs were aligned preferentially along individual nanofibers. Infiltration of the PDMS through this nanofibrous mesh onto the underlying substrate was observed and the resulting composites exhibited high optical absorption (>97%). Thickness control from 2.3 μm to 41.4 μm was obtained by varying the electrospinning time. Under laser excitation with 11 μJ pulse energy, ultrasound pressures of 1.59 MPa were achieved at 1.5 mm from the coatings. On comparing the electrospun ultrasound transmitters with a dip-coated reference fabricated using the same constituent materials and possessing identical optical absorption, a five-fold increase in the generated pressure and wider bandwidth was observed. The electrospun transmitters exhibited high optical absorption, good elastomer infiltration, and ultrasound generation capability in the range of pressures used for clinical pulse-echo imaging. All-optical ultrasound probes with such transmitters fabricated by electrospinning could be well-suited for incorporation into catheters and needles for diagnostics and therapeutic applications.

  14. Optical fiber ultrasound transmitter with electrospun carbon nanotube-polymer composite

    NASA Astrophysics Data System (ADS)

    Poduval, Radhika K.; Noimark, Sacha; Colchester, Richard J.; Macdonald, Thomas J.; Parkin, Ivan P.; Desjardins, Adrien E.; Papakonstantinou, Ioannis

    2017-05-01

    All-optical ultrasound transducers are promising for imaging applications in minimally invasive surgery. In these devices, ultrasound is transmitted and received through laser modulation, and they can be readily miniaturized using optical fibers for light delivery. Here, we report optical ultrasound transmitters fabricated by electrospinning an absorbing polymer composite directly onto the end-face of optical fibers. The composite coating consisting of an aqueous dispersion of multi-walled carbon nanotubes (MWCNTs) in polyvinyl alcohol was directly electrospun onto the cleaved surface of a multimode optical fiber and subsequently dip-coated with polydimethylsiloxane (PDMS). This formed a uniform nanofibrous absorbing mesh over the optical fiber end-face wherein the constituent MWCNTs were aligned preferentially along individual nanofibers. Infiltration of the PDMS through this nanofibrous mesh onto the underlying substrate was observed and the resulting composites exhibited high optical absorption (>97%). Thickness control from 2.3 μm to 41.4 μm was obtained by varying the electrospinning time. Under laser excitation with 11 μJ pulse energy, ultrasound pressures of 1.59 MPa were achieved at 1.5 mm from the coatings. On comparing the electrospun ultrasound transmitters with a dip-coated reference fabricated using the same constituent materials and possessing identical optical absorption, a five-fold increase in the generated pressure and wider bandwidth was observed. The electrospun transmitters exhibited high optical absorption, good elastomer infiltration, and ultrasound generation capability in the range of pressures used for clinical pulse-echo imaging. All-optical ultrasound probes with such transmitters fabricated by electrospinning could be well-suited for incorporation into catheters and needles for diagnostics and therapeutic applications.

  15. Robust Mechanical-to-Electrical Energy Conversion from Short-Distance Electrospun Poly(vinylidene fluoride) Fiber Webs.

    PubMed

    Shao, Hao; Fang, Jian; Wang, Hongxia; Lang, Chenhong; Lin, Tong

    2015-10-14

    Electrospun polyvinylidene fluoride (PVDF) nanofiber webs have shown great potential in making mechanical-to-electrical energy conversion devices. Previously, polyvinylidene fluoride (PVDF) nanofibers were produced either using near-field electrospinning (spinning distance<1 cm) or conventional electrospinning (spinning distance>8 cm). PVDF fibers produced by an electrospinning at a spinning distance between 1 and 8 cm (referred to as "short-distance" electrospinning in this paper) has received little attention. In this study, we have found that PVDF electrospun in such a distance range can still be fibers, although interfiber connection is formed throughout the web. The interconnected PVDF fibers can have a comparable β crystal phase content and mechanical-to-electrical energy conversion property to those produced by conventional electrospinning. However, the interfiber connection was found to considerably stabilize the fibrous structure during repeated compression and decompression for electrical conversion. More interestingly, the short-distance electrospun PVDF fiber webs have higher delamination resistance and tensile strength than those of PVDF nanofiber webs produced by conventional electrospinning. Short-distance electrospun PVDF nanofibers could be more suitable for the development of robust energy harvesters than conventionally electrospun PVDF nanofibers.

  16. 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.

  17. Incorporation of biodegradable electrospun fibers into calcium phosphate cement for bone regeneration.

    PubMed

    Zuo, Yi; Yang, Fang; Wolke, Joop G C; Li, Yubao; Jansen, John A

    2010-04-01

    Inherent brittleness and slow degradation are the major drawbacks for the use of calcium phosphate cements (CPCs). To address these issues, biodegradable ultrafine fibers were incorporated into the CPC in this study. Four types of fibers made of poly(epsilon-caprolactone) (PCL) (PCL12: 1.1 microm, PCL15: 1.4 microm, PCL18: 1.9 microm) and poly(l-lactic acid) (PLLA4: 1.4 microm) were prepared by electrospinning using a special water pool technique, then mixed with the CPC at fiber weight fractions of 1%, 3%, 5% and 7%. After incubation of the composites in simulated body fluid for 7 days, they were characterized by a gravimetric measurement for porosity evaluation, a three-point bending test for mechanical properties, microcomputer topography and scanning electron microscopy for morphological observation. The results indicated that the incorporation of ultrafine fibers increases the fracture resistance and porosity of CPCs. The toughness of the composites increased with the fiber fraction but was not affected by the fiber diameter. It was found that the incorporated fibers formed a channel-like porous structure in the CPCs. After degradation of the fibers, the created space and high porosity of the composite cement provides inter-connective channels for bone tissue in growth and facilitates cement resorption. Therefore, we concluded that this electrospun fiber-CPC composite may be beneficial to be used as bone fillers.

  18. 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

  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. 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.

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

    PubMed

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

    2014-08-01

    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. 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. 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. 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.

  2. 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.

  3. Mechanical characterization of glass fiber (woven roving/chopped strand mat E-glass fiber) reinforced polyester composites

    NASA Astrophysics Data System (ADS)

    Bhaskar, V. Vijaya; Srinivas, Kolla

    2017-07-01

    Polymer reinforced composites have been replacing most of the engineering material and their applications become more and more day by day. Polymer composites have been analyzing from past thirty five years for their betterment for adapting more applications. This paper aims at the mechanical properties of polyester reinforced with glass fiber composites. The glass fiber is reinforced with polyester in two forms viz Woven Rovings (WRG) and Chopped Strand Mat (CSMG) E-glass fibers. The composites are fabricated by hand lay-up technique and the composites are cut as per ASTM Standard sizes for corresponding tests like flexural, compression and impact tests, so that flexural strength, compression strength, impact strength and inter laminar shear stress(ILSS) of polymer matrix composites are analyzed. From the tests and further calculations, the polyester composites reinforced with Chopped Strand Mat glass fiber have shown better performance against flexural load, compression load and impact load than that of Woven Roving glass fiber.

  4. 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).

  5. Effect of cross-linking on properties and release characteristics of sodium salicylate-loaded electrospun poly(vinyl alcohol) fibre mats

    NASA Astrophysics Data System (ADS)

    Taepaiboon, Pattama; Rungsardthong, Uracha; Supaphol, Pitt

    2007-05-01

    Cross-linking of electrospun (e-spun) fibre mats (beaded fibre morphology with the average diameter of the fibre segments between beads being ~108 nm) of poly(vinyl alcohol) (PVA) containing sodium salicylate (SS), used as the model drug, was achieved by exposing the fibre mats to the vapour from 5.6 M aqueous solution of either glutaraldehyde or glyoxal for various exposure time intervals, followed by a heat treatment in a vacuum oven. With increasing the exposure time in the cross-linking chamber, the morphology of the e-spun fibre mats gradually changed from a porous to dense structure. Both the degree of swelling and the percentage of weight loss of the cross-linked fibre mats (i.e. ~200-530% and ~15-57%, respectively) were lower than those of the untreated ones (i.e. ~610% and ~67%, respectively). Cross-linking was also responsible for the monotonic increase in the storage moduli of the cross-linked SS-loaded e-spun PVA fibre mats with increasing exposure time in the cross-linking chamber. The release characteristic of the model drug from the SS-loaded e-spun PVA fibre mats both before and after cross-linking was assessed by the transdermal diffusion through a pig skin method. The cumulative release of the drug from these matrices could be divided into two stages: 0-4 and 4-72 h, in which the amount of SS released in the first stage increased very rapidly, while it was much slower in the second stage. Cross-linking slowed down the release of SS from the drug-loaded fibre mats appreciably and both the rate of release and the total amount of the drug released were decreasing functions of the exposure time interval in the cross-linking chamber. Lastly, the cross-linked SS-loaded e-spun PVA fibre mats were non-toxic to normal human dermal fibroblasts.

  6. 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.

  7. 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

  8. 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

  9. 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

    2015-12-09

    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.

  10. 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.

  11. Fiber angle and aspect ratio influence the shear mechanics of oriented electrospun nanofibrous scaffolds.

    PubMed

    Driscoll, Tristan P; Nerurkar, Nandan L; Jacobs, Nathan T; Elliott, Dawn M; Mauck, Robert L

    2011-11-01

    Fibrocartilages, including the knee meniscus and the annulus fibrosus (AF) of the intervertebral disc, play critical mechanical roles in load transmission across joints and their function is dependent upon well-defined structural hierarchies, organization, and composition. All, however, are compromised in the pathologic transformations associated with tissue degeneration. Tissue engineering strategies that address these key features, for example, aligned nanofibrous scaffolds seeded with mesenchymal stem cells (MSCs), represent a promising approach for the regeneration of these fibrous structures. While such engineered constructs can replicate native tissue structure and uniaxial tensile properties, the multidirectional loading encountered by these tissues in vivo necessitates that they function adequately in other loading modalities as well, including shear. As previous findings have shown that native tissue tensile and shear properties are dependent on fiber angle and sample aspect ratio, respectively, the objective of the present study was to evaluate the effects of a changing fiber angle and sample aspect ratio on the shear properties of aligned electrospun poly(ε-caprolactone) (PCL) scaffolds, and to determine how extracellular matrix deposition by resident MSCs modulates the measured shear response. Results show that fiber orientation and sample aspect ratio significantly influence the response of scaffolds in shear, and that measured shear strains can be predicted by finite element models. Furthermore, acellular PCL scaffolds possessed a relatively high shear modulus, 2-4 fold greater than native tissue, independent of fiber angle and aspect ratio. It was further noted that under testing conditions that engendered significant fiber stretch, the aggregate resistance to shear was higher, indicating a role for fiber stretch in the overall shear response. Finally, with time in culture, the shear modulus of MSC laden constructs increased, suggesting that

  12. 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.

  13. Fabrication and in vivo evaluation of hydroxyapatite/carbon nanotube electrospun fibers for biomedical/dental application.

    PubMed

    Khan, A S; Hussain, A N; Sidra, L; Sarfraz, Z; Khalid, H; Khan, M; Manzoor, F; Shahzadi, L; Yar, M; Rehman, I U

    2017-11-01

    The aim was to synthesize bioactive electrospun fibers for biomedical and dental application with improved biocompatibility. In situ precipitation of nano-hydroxyapatite (nHA) was performed with various concentrations (0.5%, 1%, 2%, 3%, and 5% wt/wt) of functionalized multi-walled-carbon nanotubes (MWCNTs) by using microwave irradiation technique. The obtained composites were characterized by Fourier Transform Infrared (FTIR), X-ray Diffraction (XRD), Thermogravimetric Analysis/Differential Scanning Calorimetry (TGA/DSC), and the cylindrical discs were made for mechanical testing. The failure behavior was analyzed by Scanning Electron Microscope (SEM). CNT and HA/CNT were silanized with γ-methacryloxypropyl-trimethoxysilane (MPTS) and mixed with polyvinyl alcohol (10% wt./vol.) and electrospun to fabricate fibers. The biocompatibility of both fibers was accessed by their effects on angiogenesis in a chick chorioallantoic membrane (CAM) assay. The electrospun fibers were analyzed by SEM. FTIR confirmed the structural behavior of pre and post-silanized HA/CNT. XRD showed the phase purity and crystallinity before and after heat treatment. Mechanical properties showed that 3% loaded HA/CNT has higher compressive strength (100.5±5.9MPa) compared to others and the failure behavior exhibited dispersion of CNT in HA matrix. The HA/CNT electrospun fibers showed significantly more blood vessels formation compared to CNT fibers. These HA/CNT electrospun fibers showed promising results in terms of biocompatibility and with improved mechanical properties of CNT reinforced composites, they can be used in load bearing clinical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. 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

  15. Electrospun polyurethane/Eudragit ® L100-55 composite mats for the pH dependent release of paclitaxel on duodenal stent cover application.

    PubMed

    Aguilar, Ludwig Erik; Unnithan, Afeesh Rajan; Amarjargal, Altangerel; Tiwari, Arjun Prasad; Hong, Seong Tshool; Park, Chan Hee; Kim, Cheol Sang

    2015-01-15

    A nanofiber composite mat of PU and Eudragit(®) L100-55 was created using electrospinning process. The pH dependent release of paclitaxel was successfully done with the use of PU/EL100-55 nanocomposite mats as the controlling platform. The morphology of the nanofiber composites was surveyed using FESEM and ratios of the polymers affects the diameter of the nanofiber. Characterization of the nanofiber composite mat was done using FTIR, DSC-TGA method. The release rate of paclitaxel was determined and analyzed by in vitro drug release method. In order to mimic the condition of a human duodenum, the fibers were submersed on PBS of different pH levels (4.0, 6.0,) respectively, and then analyzed using high performance liquid chromatography (HPLC). Composite mats submersed in PBS with pH 4.0 showed lesser release profile compared to mats submersed in PBS with pH of 6.0. The composite mat has adequate mechanical properties and in vitro cell biocompatibility indicating that the material can be used for drug eluting stent cover application. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. Highly Efficient Reusable Sponge-Type Catalyst Carriers Based on Short Electrospun Fibers.

    PubMed

    Duan, Gaigai; Koehn-Serrano, Melissa; Greiner, Andreas

    2017-02-01

    This study reports on gold nanoparticles (AuNPs) immobilized in a sponge made of short electrospun fibers (Au-sponge), which show surprisingly high reaction rates at extremely low gold amount. Au-sponges are made by freeze-drying of dispersions of short electrospun fibers with preimmobilization of AuNPs. The resulting Au-sponges show very low densities around 7 mg cm(-3) corresponding to a pore volume of about 150 mL g(-1) , but low surface area and very low amount of AuNPs in the range of 0.29-3.56 wt%. In general, catalysts with immobilized AuNPs show much low reaction rates compared to systems with dispersed AuNPs. By contrast, the Au-sponge catalyst with immobilized AuNPs is discerned here as an extremely efficient catalyst even superior to other systems with dispersed AuNPs. The fidelity of the Au-sponges after reactions is good enough for manifold use and thereby provides a sustainable catalyst design as well. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. A novel electrospun polysulfone fiber membrane: application to advanced treatment of secondary bio-treatment sewage.

    PubMed

    Xu, Z; Gu, Q; Hu, H; Li, F

    2008-01-01

    Electrospun nanofibers and fine fibers have been used to remove submicron particles in air filtration. In this paper, direct-and polyaluminium chloride (PAC) pre-coagulation filtration of secondary bio-treatment sewage was studied using electrospun polysulfone fiber membrane (EPSFM). According to the results obtained, for direct filtration, suspended solids (SS), chemical oxygen demand (COD(Cr)) and NH3-N decreased 86.7, 71.2, 91.7% respectively, in filtrate of secondary bio-treatment sewage, while for PAC pre-coagulation filtration, the removal rate of SS, COD(Cr) and NH3-N reached 91.3, 85.3, 93.3 % respectively. EPSFM had a high efficiency in removing NH3-N, COD(Cr) and SS, especially for micron and submicron particles. EPSFM can reduce the content of some toxic metals, such as Cu, Zn and Ti, through interception and adsorption mechanism and can also remove dissolved organic matter such as humics and proteins through interception mechanism. EPSFM can remove some of volatile organic chemicals (VOCs) by adsorption and filtration, the removal rate of VOCs was in the range of 59-100 %. The number of VOCs in secondary bio-treatment sewage and its filtrate from direct filtration were 27 and 18 respectively, the major VOCs were benzene-, cyclohexane-, adamantine- and hydrocarbon derivates.

  18. 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

  19. Effect of polyvinylidene fluoride electrospun fiber orientation on neural stem cell differentiation.

    PubMed

    Lins, Luanda C; Wianny, Florence; Livi, Sebastien; Dehay, Colette; Duchet-Rumeau, Jannick; Gérard, Jean-François

    2016-08-29

    Electrospun polymer piezoelectric fibers can be used in neural tissue engineering (NTE) to mimic the physical, biological, and material properties of the native extracellular matrix. In this work, we have developed scaffolds based on polymer fiber architectures for application in NTE. To study the role of such three-dimensional scaffolds, a rotating drum collector was used for electrospinning poly(vinylidene) fluoride (PVDF) polymer at various rotation speeds. The morphology, orientation, polymorphism, as well as the mechanical behavior of the nonaligned and aligned fiber-based architectures were characterized. We have demonstrated that the jet flow and the electrostatic forces generated by electrospinning of PVDF induced local conformation changes which promote the generation of the β-phase. Fiber anisotropy could be a critical feature for the design of suitable scaffolds for NTEs. We thus assessed the impact of PVDF fiber alignment on the behavior of monkey neural stem cells (NSCs). NSCs were seeded on nonaligned and aligned scaffolds and their morphology, adhesion, and differentiation capacities into the neuronal and glial pathways were studied using microscopic techniques. Significant changes in the growth and differentiation capacities of NSCs into neuronal and glial cells as a function of the fiber alignment were evidenced. These results demonstrate that PVDF scaffolds may serve as instructive scaffolds for NSC survival and differentiation, and may be valuable tools for the development of cell- and scaffold-based strategies for neural repair. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016. © 2016 Wiley Periodicals, Inc.

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

    PubMed

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

    2016-10-21

    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.

  1. 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.

  2. 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.

  3. 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.

  4. Atomic layer deposition of metal oxide patterns on nonwoven fiber mats using localized physical compression.

    PubMed

    Sweet, William J; Oldham, Christopher J; Parsons, Gregory N

    2014-06-25

    Patterning is an essential part of many industrial processes from printing to semiconductor manufacturing. In this work, we demonstrate a new method to pattern and selectively coat nonwoven textiles by atomic layer deposition (ALD) using compressive mask patterning. A physical mask combined with mechanical compression allows lateral definition and fidelity of the ALD coating to be controlled. We produce features of several sizes on different nonwoven fiber materials and demonstrate the ability to limit diffusion effects to within <200 μm of the pattern edge. Lateral and vertical penetration of reactive growth species into nonwoven mats is investigated by plan-view and cross-sectional imaging. Vertical growth is also analyzed by imaging coating depth into fiber mat stacks. We develop a fully quantitative transport model that describes well the effect of fiber structure and mechanical compression on the extent of coating under the physical mask. This method could be implemented for high-volume patterning for applications including flexible electronics.

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

    PubMed

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

    2012-02-01

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

  6. 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

  7. Investigation of Electrospun Poly Vinyl Alcohol Fibers Towards the Development of Manufacturable Wound Dressings

    NASA Astrophysics Data System (ADS)

    Vora, Asad

    Polymers such as polyvinyl alcohol, chitosan, and starch have excellent bio-compatible and bio-degradable properties. Their applications in drug delivery, wound dressings, artificial cartilage materials have increased dramatically due to their much sought-after renewable and biological properties. Hence, polyvinyl alcohol has been chosen for this study to test the feasibility of polyvinyl alcohol nanofibers towards the manufacturable wound dressings. Polyvinyl alcohol nanofibers are prepared via electrospinning technique, where different wt% polyvinyl alcohol solutions are prepared. The fibers were optimized by varying important electrospninning parameters which include voltage applied, the collector-needle distance and flow rate. Morphology and structure of the electrospun fibers are analysed using scanning electron microscopy and fourier transform infrared respectively. The diameter of fibers obtained was found to be in the range of 100 nm-160 nm. Thermal stability was examined using DSC and TGA characterization technique and fibers are found to be stable up to 220oC. Finally, each weight sample of PVA fibers are analysed by goniometer for wettability and is found to be hydrophilic.

  8. 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.

  9. Processing and characterization of α-elastin electrospun membranes

    NASA Astrophysics Data System (ADS)

    Araujo, J.; Padrão, J.; Silva, J. P.; Dourado, F.; Correia, D. M.; Botelho, G.; Gomez Ribelles, J. L.; Lanceros-Méndez, S.; Sencadas, V.

    2014-06-01

    Elastin isolated from fresh bovine ligaments was dissolved in a mixture of 1,1,1,3,3,3-Hexafluoro-2-propanol and water were electrospun into fiber membranes under different processing conditions. Fiber mats of randomly and aligned fibers were obtained with fixed and rotating ground collectors and fibrils were composed by thin ribbons whose width depends on electrospinning conditions; fibrils with 721 nm up to 2.12 μm width were achieved. After cross-linking with glutaraldehyde, α-elastin can uptake as much as 1700 % of PBS solution and a slight increase on fiber thickness was observed. The glass transition temperature of electrospun fiber mats was found to occur at ˜80 °C. Moreover, α-Elastin showed to be a perfect elastomeric material, and no mechanical hysteresis was found in cycle mechanical measurements. The elastic modulus obtained for random and aligned fibers mats in a PBS solution was 330±10 kPa and 732±165 kPa, respectively. Finally, the electrospinning and cross-linking process does not inhibit MC-3T3-E1 cell adhesion. Cell culture results showed good cell adhesion and proliferation in the cross-linked elastin fiber mats.

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

    PubMed

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

    2013-12-02

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

  11. 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.

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

    Treesearch

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

    2012-01-01

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

  13. 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.

  14. 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.

  15. 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

  16. 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

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

    NASA Astrophysics Data System (ADS)

    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.

  18. Griffithsin-Modified Electrospun Fibers as a Delivery Scaffold To Prevent HIV Infection

    PubMed Central

    Grooms, Tiffany N.; Vuong, Hung R.; Tyo, Kevin M.; Malik, Danial A.; Sims, Lee B.; Whittington, Carli P.; Palmer, Kenneth E.

    2016-01-01

    Despite current prophylactic strategies, sexually transmitted infections (STIs) remain significant contributors to global health challenges, spurring the development of new multipurpose delivery technologies to protect individuals from and treat virus infections. However, there are few methods currently available to prevent and no method to date that cures human immunodeficiency virus (HIV) infection or combinations of STIs. While current oral and topical preexposure prophylaxes have protected against HIV infection, they have primarily relied on antiretrovirals (ARVs) to inhibit infection. Yet continued challenges with ARVs include user adherence to daily treatment regimens and the potential toxicity and antiviral resistance associated with chronic use. The integration of new biological agents may avert some of these adverse effects while also providing new mechanisms to prevent infection. Of the biologic-based antivirals, griffithsin (GRFT) has demonstrated potent inhibition of HIV-1 (and a multitude of other viruses) by adhering to and inactivating HIV-1 immediately upon contact. In parallel with the development of GRFT, electrospun fibers (EFs) have emerged as a promising platform for the delivery of agents active against HIV infection. In the study described here, our goal was to extend the mechanistic diversity of active agents and electrospun fibers by incorporating the biologic GRFT on the EF surface rather than within the EFs to inactivate HIV prior to cellular entry. We fabricated and characterized GRFT-modified EFs (GRFT-EFs) with different surface modification densities of GRFT and demonstrated their safety and efficacy against HIV-1 infection in vitro. We believe that EFs are a unique platform that may be enhanced by incorporation of additional antiviral agents to prevent STIs via multiple mechanisms. PMID:27550363

  19. Griffithsin-Modified Electrospun Fibers as a Delivery Scaffold To Prevent HIV Infection.

    PubMed

    Grooms, Tiffany N; Vuong, Hung R; Tyo, Kevin M; Malik, Danial A; Sims, Lee B; Whittington, Carli P; Palmer, Kenneth E; Matoba, Nobuyuki; Steinbach-Rankins, Jill M

    2016-11-01

    Despite current prophylactic strategies, sexually transmitted infections (STIs) remain significant contributors to global health challenges, spurring the development of new multipurpose delivery technologies to protect individuals from and treat virus infections. However, there are few methods currently available to prevent and no method to date that cures human immunodeficiency virus (HIV) infection or combinations of STIs. While current oral and topical preexposure prophylaxes have protected against HIV infection, they have primarily relied on antiretrovirals (ARVs) to inhibit infection. Yet continued challenges with ARVs include user adherence to daily treatment regimens and the potential toxicity and antiviral resistance associated with chronic use. The integration of new biological agents may avert some of these adverse effects while also providing new mechanisms to prevent infection. Of the biologic-based antivirals, griffithsin (GRFT) has demonstrated potent inhibition of HIV-1 (and a multitude of other viruses) by adhering to and inactivating HIV-1 immediately upon contact. In parallel with the development of GRFT, electrospun fibers (EFs) have emerged as a promising platform for the delivery of agents active against HIV infection. In the study described here, our goal was to extend the mechanistic diversity of active agents and electrospun fibers by incorporating the biologic GRFT on the EF surface rather than within the EFs to inactivate HIV prior to cellular entry. We fabricated and characterized GRFT-modified EFs (GRFT-EFs) with different surface modification densities of GRFT and demonstrated their safety and efficacy against HIV-1 infection in vitro We believe that EFs are a unique platform that may be enhanced by incorporation of additional antiviral agents to prevent STIs via multiple mechanisms. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  20. Highly conductive and flexible nylon-6 nonwoven fiber mats formed using tungsten atomic layer deposition.

    PubMed

    Kalanyan, Berç; Oldham, Christopher J; Sweet, William J; Parsons, Gregory N

    2013-06-12

    Low-temperature vapor-phase tungsten atomic layer deposition (ALD) using WF6 and dilute silane (SiH4, 2% in Ar) can yield highly conductive coatings on nylon-6 microfiber mats, producing flexible and supple nonwovens with conductivity of ∼1000 S/cm. We find that an alumina nucleation layer, reactant exposure, and deposition temperature all influence the rate of W mass uptake on 3D fibers, and film growth rate is calibrated using high surface area anodic aluminum oxide. Transmission electron microscopy (TEM) reveals highly conformal tungsten coatings on nylon fibers with complex "winged" cross-section. Using reactant gas "hold" sequences during the ALD process, we conclude that reactant species can transport readily to reactive sites throughout the fiber mat, consistent with conformal uniform coverage observed by TEM. The conductivity of 1000 S/cm for the W-coated nylon is much larger than found in other conductive nonwovens. We also find that the nylon mats maintain 90% of their conductivity after being flexed around cylinders with radii as small as 0.3 cm. Metal ALD coatings on nonwovens make possible the solvent-free functionalization of textiles for electronic applications.

  1. Hierarchical Chitin Fibers with Aligned Nanofibrillar Architectures: A Nonwoven-Mat Separator for Lithium Metal Batteries.

    PubMed

    Kim, Joong-Kwon; Kim, Do Hyeong; Joo, Se Hun; Choi, Byeongwook; Cha, Aming; Kim, Kwang Min; Kwon, Tae-Hyuk; Kwak, Sang Kyu; Kang, Seok Ju; Jin, Jungho

    2017-06-27

    Here, we introduce regenerated fibers of chitin (Chiber), the second most abundant biopolymer after cellulose, and propose its utility as a nonwoven fiber separator for lithium metal batteries (LMBs) that exhibits an excellent electrolyte-uptaking capability and Li-dendrite-mitigating performance. Chiber is produced by a centrifugal jet-spinning technique, which allows a simple and fast production of Chibers consisting of hierarchically aligned self-assembled chitin nanofibers. Following the scrutinization on the Chiber-Li-ion interaction via computational methods, we demonstrate the potential of Chiber as a nonwoven mat-type separator by monitoring it in Li-O2 and Na-O2 cells.

  2. 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.

  3. Intermolecular Interactions and the Release Pattern of Electrospun Curcumin-Polyvinyl(pyrrolidone) Fiber.

    PubMed

    Rahma, Annisa; Munir, Muhammad Miftahul; Khairurrijal; Prasetyo, Anton; Suendo, Veinardi; Rachmawati, Heni

    2016-01-01

    An electrospun fiber of polyvinyl(pyrrolidone) (PVP)-Tween 20 (T20) with curcumin as the encapsulated drug has been developed. A study of intermolecular interactions was performed using Raman spectroscopy, Fourier transform infrared (FT-IR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). The Raman and FT-IR studies showed that curcumin preferrably interacted with T20 and altered PVP chain packing, as supported by XRD and physical stability data. The hydroxyl stretching band in PVP shifted to a lower wavenumber with higher intenstity in the presence of curcumin and PVP, indicating that hydrogen bond formation is more intense in a curcumin or curcumin-T20 containing fiber. The thermal pattern of the fiber did not indicate phase separation. The conversion of curcumin into an amorphous state was confirmed by XRD analysis. An in vitro release study in phosphate buffer pH 6.8 showed that intermolecular interactions between each material influenced the drug release rate. However, low porosity was found to limit the hydrogen bond-mediated release.

  4. 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.

  5. Synthesis of continuous boron nitride nanofibers by solution coating electrospun template fibers.

    PubMed

    Qiu, Yejun; Yu, Jie; Yin, Jing; Tan, Cuili; Zhou, Xiaosong; Bai, Xuedong; Wang, Enge

    2009-08-26

    Continuous boron nitride nanofibers (BNNFs) have been synthesized from boric oxide (B(2)O(3)) coatings deposited on stabilized electrospun polyacrylonitrile fibers (S-PANFs). The B(2)O(3) overcoatings were prepared by impregnating the S-PANFs with B(2)O(3) ethanol solutions. By successive heat treatments at 800 degrees C in NH(3)/O(2) mixture, 1100 degrees C in pure NH(3), and 1500 degrees C in N(2), the S-PANFs were fully removed and the B(2)O(3) coatings deflate to form solid fibers and transform into the BNNFs. The S-PANF template was fully removed by introducing O(2) during nitridation, and thus resulted in the formation of the BNNFs. The diameter of the BNNFs can be effectively controlled by changing the mass concentration of the B(2)O(3) solution, and diameters from 43 to 230 nm were obtained by changing the B(2)O(3) mass concentration from 0.25% to 4.8%. The obtained BNNFs are crystallized with the (002) planes oriented in parallel to the fiber axis. This method provides a powerful tool for obtaining BNNFs with controllable diameters, especially extremely thin BNNFs.

  6. 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

    2012-02-08

    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. © 2011 American Chemical Society

  7. 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.

  8. Interactions between endothelial cells and electrospun methacrylic terpolymer fibers for engineered vascular replacements.

    PubMed

    Veleva, A N; Heath, D E; Johnson, J K; Nam, J; Patterson, C; Lannutti, J J; Cooper, S L

    2009-12-15

    A compliant terpolymer made of hexylmethacrylate (HMA), methylmethacrylate (MMA), and methacrylic acid (MAA) intended for use in small diameter vascular graft applications has been developed. The mechanical properties and in vitro biostability of this terpolymer have been previously characterized. The goal of this investigation was to examine the interactions between endothelial cells and the new terpolymer and to evaluate endothelial cell function. Electrospinning was used to produce both oriented and random terpolymer fiber scaffolds. Smooth solution cast films and tissue culture polystyrene were used as negative and positive controls, respectively. Human blood outgrowth endothelial cells and human umbilical vein endothelial cells were incubated with the test and control samples and characterized with respect to initial cell attachment, proliferation, viability, and maintenance of the endothelial cell phenotype. It was found that the terpolymer is cytocompatible allowing endothelial cell growth, with random fibers being more effective in promoting enhanced cellular activities than oriented fibers. In addition, endothelial cells cultured on these substrates appeared to maintain their phenotype. The results from this study demonstrate that electrospun HMA:MMA:MAA terpolymer has the potential to be used successfully in fabricating small diameter blood vessel replacements.

  9. Antimicrobial electrospun ultrafine fibers from zein containing eucalyptus essential oil/cyclodextrin inclusion complex.

    PubMed

    Dias Antunes, Mariana; da Silva Dannenberg, Guilherme; Fiorentini, Ângela Maria; Pinto, Vânia Zanella; Lim, Loong-Tak; da Rosa Zavareze, Elessandra; Dias, Alvaro Renato Guerra

    2017-11-01

    The aim of this study was to produce ultrafine fibers from zein incorporated with a complex of eucalyptus essential oil (EEO) and β-cyclodextrin (β-CD) with antimicrobial properties by electrospinning technique. The EEO was characterized by chemical composition and antimicrobial tests against three Gram positive and four Gram negative bacteria. The inclusion complex (IC) was prepared with β-CD and EEO by co-precipitation technique and added at different concentrations in zein polymer solution using aqueous ethanol as solvent. The morphology, thermal properties, functional groups, and antimicrobial activity against L. monocytogenes and S. aureus of the ultrafine fibers were evaluated. The composite membranes containing 24% IC exhibited a greater reduction of growth as compared to the fibers without addition of IC. For L. monocytogenes the growth reduction was 28.5% and for S. aureus it was 24.3%. The electrospun IC-β-CD/EEO composite membranes are promising for use in antimicrobial applications, such as food packaging. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. 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

  11. Regulated non-viral gene delivery from coaxial electrospun fiber mesh scaffolds.

    PubMed

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

    2010-04-02

    and 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.

  12. A highly flexible piezoelectret-fiber pressure sensor based on highly aligned P(VDF-TrFE) electrospun fibers

    NASA Astrophysics Data System (ADS)

    Ke, Jun-Yi; Chu, Hsin-Jung; Hsu, Yu-Hsiang; Lee, Chih-Kung

    2017-04-01

    P(VDF-TrFE) is a ferroelectric material having a strong piezoelectric effect, a good chemical stability, chemical resistance and biocompatibility. Therefore, it is suitable for the development of flexible pressure sensors in biological applications. Using electrospinning method and a drum collector, P(VDF-TrFE) nanofibers are aligned and formed an ultrathin film sheet with a thickness of 15 to 30 μm. A 140 °C annealing process and a corona discharge poling process are conducted to increase the performance of β phase piezoelectricity. Based on this technology, a highly flexible piezoelectret pressure sensor is developed for measuring muscle movement on the surface of human body. The orientation of electrospun P(VDFTrFE) fibers and poling direction are studied to enhance the sensitivity of the piezoelectret-fiber pressure sensor. Preliminary study shows that the sensitivity of piezoelectret-fiber pressure sensor can be 110.37 pC/Pa with a high signal to noise ratio. Sensor design, experimental studies, and biological application are detailed in this paper.

  13. MOFabric: Electrospun Nanofiber Mats from PVDF/UiO-66-NH2 for Chemical Protection and Decontamination.

    PubMed

    Lu, Annie Xi; McEntee, Monica; Browe, Matthew A; Hall, Morgan G; DeCoste, Jared B; Peterson, Gregory W

    2017-04-19

    Textiles capable of capture and detoxification of toxic chemicals, such as chemical-warfare agents (CWAs), are of high interest. Some metal-organic frameworks (MOFs) exhibit superior reactivity toward CWAs. However, it remains a challenge to integrate powder MOFs into engineered materials like textiles, while retaining functionalities like crystallinity, adsorptivity, and reactivity. Here, we present a simple method of electrospinning UiO-66-NH2, a zirconium MOF, with polyvinylidene fluoride (PVDF). The electrospun composite, which we refer to as "MOFabric", exhibits comparable crystal patterns, surface area, chlorine uptake, and simulant hydrolysis to powder UiO-66-NH2. The MOFabric is also capable of breaking down GD (O-pinacolyl methylphosphonofluoridae) faster than powder UiO-66-NH2. Half-life of GD monitored by solid-state NMR for MOFabric is 131 min versus 315 min on powder UiO-66-NH2.

  14. 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.

  15. 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.

  16. Electrospun carbon nanofibers for electrochemical capacitor electrodes

    NASA Astrophysics Data System (ADS)

    Wang, Tong

    The objective of this work is to electrospin poly(acrylonitrile) (PAN) based nanofibers with controlled diameter and to stabilize and carbonize them for developing meso-porous carbon for application as electrochemical capacitor electrodes. A sacrificial polymer, poly(styrene-co-acrylonitrile) (SAN) has been used to control porosity. Carbon nanotubes (CNT) have been used to increase electrode conductivity and hence power density. The study has been divided into two parts. In part I, electrospinning behavior of PAN and PAN/CNT has been studied. The diameter of electrospun PAN fibers was monitored as a function of polymer molecular weight, solution concentration, solution flow rate, distance between the spinneret and the target, and the applied voltage. Bead free PAN fibers of 60 nm diameter have been electrospun. Various electrospun fibers have been characterized by wide angle X-ray diffraction and by Raman spectroscopy. Electrospinning process has been observed by high speed photography. In part II, the electrospun PAN, PAN/SAN, and PAN/SAN/CNT fiber mats were stabilized, carbonized, and processed into electrochemical capacitor electrodes. The performance of the electrochemical capacitors was tested by the constant current charge/discharge and cyclic voltammetry in 6 molar potassium hydroxide aqueous solution. The surface area and pore size distribution of the electrodes were measured using N2 adsorption and desorption. The effect of surface area and pore size distribution on the capacitance performance has been studied. The capacitance performance of various carbonized electrospun fibers mats have been compared to those of the PAN/SAN/CNT film, carbon nanotube bucky paper, and activated carbon pellet. The capacitance of PAN/SAN/CNT fiber mat over 200 F/g (at a current density of 1 A/g) and the power density approaching 1 kW/kg have been observed. Addition of 1 wt% carbon nanotubes in PAN/SAN, improves the power density by a factor of four. For comparison, the

  17. 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.

  18. Chitosan-based electrospun nanofibrous mats, hydrogels and cast films: novel anti-bacterial wound dressing matrices.

    PubMed

    Shahzad, Sohail; Yar, Muhammad; Siddiqi, Saadat Anwar; Mahmood, Nasir; Rauf, Abdul; Qureshi, Zafar-ul-Ahsan; Anwar, Muhammad Sabieh; Afzaal, Shahida

    2015-03-01

    The development of highly efficient anti-bacterial wound dressings was carried out. For this purpose nanofibrous mats, hydrogels and films were synthesized from chitosan, poly(vinyl alcohol) and hydroxyapatite. The physical/chemical interactions of the synthesized materials were evaluated by FTIR. The morphology, structure; average diameter and pore size of the materials were investigated by scanning electron microscopy. The hydrogels showed a greater degree of swelling as compared to nanofibrous mats and films in phosphate buffer saline solution of pH 7.4. The in vitro drug release studies showed a burst release during the initial period of 4 h and then a sustained release profile was observed in the next upcoming 20 h. The lyophilized hydrogels showed a more slow release as compared to nanofibrous mats and films. Antibacterial potential of drug released solutions collected after 24 h of time interval was determined and all composite matrices showed good to moderate activity against Gram-positive and Gram-negative bacterial strains respectively. To determine the cytotoxicity, cell culture was performed for various cefixime loaded substrates by using neutral red dye uptake assay and all the matrices were found to be non-toxic.

  19. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Electrospun silk fibroin fiber diameter influences in vitro dermal fibroblast behavior and promotes healing of ex vivo wound models

    PubMed Central

    Hodgkinson, Tom; Yuan, Xue-Feng

    2014-01-01

    Replicating the nanostructured components of extracellular matrix is a target for dermal tissue engineering and regenerative medicine. Electrospinning Bombyx mori silk fibroin (BMSF) allows the production of nano- to microscale fibrous scaffolds. For BMSF electrospun scaffolds to be successful, understanding and optimizing the cellular response to material morphology is essential. Primary human dermal fibroblast response to nine variants of BMSF scaffolds composed of nano- to microscale fibers ranging from ~250 to ~1200 nm was assessed in vitro with regard to cell proliferation, viability, cellular morphology, and gene expression. BMSF support of epithelial migration was then assessed through utilization of a novel ex vivo human skin wound healing model. Scaffolds composed of the smallest diameter fibers, ~250 -300 nm, supported cell proliferation significantly more than fibers with diameters approximately 1 μm (p < 0.001). Cell morphology was observed to depart from a stellate morphology with numerous cell -fiber interactions to an elongated, fiber-aligned morphology with interaction predominately with single fibers. The expressions of extracellular matrix genes, collagen types I and III (p < 0.001), and proliferation markers, proliferating cell nuclear antigen (p < 0.001), increased with decreasing fiber diameter. The re-epithelialization of ex vivo wound models was significantly improved with the addition of BMSF electrospun scaffolds, with migratory keratinocytes incorporated into scaffolds. BMSF scaffolds with nanofibrous architectures enhanced proliferation in comparison to microfibrous scaffolds and provided an effective template for migratory keratinocytes during re-epithelialization. The results may aid in the development of effective BMSF electrospun scaffolds for wound healing applications PMID:25383171

  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. Prediction of thermal conductivity of polyvinylpyrrolidone (PVP) electrospun nanocomposite fibers using artificial neural network and prey-predator algorithm.

    PubMed

    Khan, Waseem S; Hamadneh, Nawaf N; Khan, Waqar A

    2017-01-01

    In this study, multilayer perception neural network (MLPNN) was employed to predict thermal conductivity of PVP electrospun nanocomposite fibers with multiwalled carbon nanotubes (MWCNTs) and Nickel Zinc ferrites [(Ni0.6Zn0.4) Fe2O4]. This is the second attempt on the application of MLPNN with prey predator algorithm for the prediction of thermal conductivity of PVP electrospun nanocomposite fibers. The prey predator algorithm was used to train the neural networks to find the best models. The best models have the minimal of sum squared error between the experimental testing data and the corresponding models results. The minimal error was found to be 0.0028 for MWCNTs model and 0.00199 for Ni-Zn ferrites model. The predicted artificial neural networks (ANNs) responses were analyzed statistically using z-test, correlation coefficient, and the error functions for both inclusions. The predicted ANN responses for PVP electrospun nanocomposite fibers were compared with the experimental data and were found in good agreement.

  3. Picosecond laser ablation of polyamide electrospun nanofibers

    NASA Astrophysics Data System (ADS)

    Götze, Marco; Krimig, Olaf; Kürbitz, Tobias; Henning, Sven; Heilmann, Andreas; Hillrichs, Georg

    2017-02-01

    Electrospun nanofibers mats have a great potential in tissue engineering and regenerative medicine. Their high porosity and enormous volume to surface ratio stimulate the growth and adhesion of mammalian cells and serve as a stable support structure. These suitable properties can be further optimized by structuring of the nanofibers. Ultrashort pulsed lasers can be used for modifying of the electrospun nanofibers without significant heat exposure. It seems also possible to generate very fine cuts from the fiber mats. In this study, polyamide electrospun nanofibers samples were processed with picosecond UV-laser irradiation (λ = 355 nm, τ = 15 ps). The samples were processed in dry, wet and immersed condition. To optimize cutting and structuring of nanofiber tissue flakes, the influence of different laser parameters on line widths, edge quality, heat-affected zone (HAZ) and the contamination of the fibers by ablated particles (debris) were examined. One additional aim was the minimization of the flake size. It was possible to generate nanofiber flakes in the sub-millimeter range. The quality of the nanofiber flakes could be improved by ablation near the ablation threshold of the material. For cutting under wet conditions shrinking of the flakes has to be taken into account.

  4. 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.

  5. Oral fast-dissolving drug delivery membranes prepared from electrospun polyvinylpyrrolidone ultrafine fibers

    NASA Astrophysics Data System (ADS)

    Yu, Deng-Guang; Shen, Xia-Xia; Branford-White, Chris; White, Kenneth; Zhu, Li-Min; Bligh, S. W. Annie

    2009-02-01

    Oral fast-dissolving drug delivery membranes (FDMs) for poorly water-soluble drugs were prepared via electrospinning technology with ibuprofen as the model drug and polyvinylpyrrolidone (PVP) K30 as the filament-forming polymer and drug carrier. Results from differential scanning calorimetry, x-ray diffraction, and morphological observations demonstrated that ibuprofen was distributed in the ultrafine fibers in the form of nanosolid dispersions and the physical status of drug was an amorphous or molecular form, different from that of the pure drug and a physical mixture of PVP and ibuprofen. Fourier-transform infrared spectroscopy results illustrated that the main interactions between PVP and ibuprofen were mediated through hydrogen bonding. Pharmacotechnical tests showed that FDMs with different drug contents had almost the same wetting and disintegrating times, about 15 and 8 s, respectively, but significantly different drug dissolution rates due to the different physical status of the drug and the different drug-release-controlled mechanisms. 84.9% and 58.7% of ibuprofen was released in the first 20 s for FDMs with a drug-to-PVP ratio of 1:4 and 1:2, respectively. Electrospun ultrafine fibers have the potential to be used as solid dispersions to improve the dissolution profiles of poorly water-soluble drugs or as oral fast disintegrating drug delivery systems.

  6. 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.

  7. 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.

  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. Electrospun tri-layered zein/PVP-GO/zein nanofiber mats for providing biphasic drug release profiles.

    PubMed

    Lee, Hoik; Xu, Gang; Kharaghani, Davood; Nishino, Masayoshi; Song, Kyung Hun; Lee, Jung Soon; Kim, Ick Soo

    2017-10-05

    Simple sequential electrospinning was utilized to create a functional tri-layered nanofiber mesh that achieves time-regulated biphasic drug release behavior. A tri-layered nanofiber mesh -composed of zein and poly(vinylpyrrolidone) (PVP) as the top/bottom and middle layers, respectively - was constructed through sequential electrospinning with ketoprofen (KET) as the model drug. PVP was blended with graphene oxide (GO) to improve the drug release functionality of PVP nanofiber as well as its mechanical properties. Scanning electron microscopy confirmed that the resultant nanofibers had a linear morphology, smooth surface, and tri-layered structure. In addition, X-ray diffraction patterns, differential scanning calorimetric analyses, and Fourier transform infrared spectra verified that the drugs were uniformly dispersed throughout the nanofiber due to good compatibility between the polymer and KET induced by hydrogen interaction. In vitro release test of the tri-layered structure, each component of which had distinct release features, successfully demonstrated time-regulated biphasic drug release. Also, it was confirmed that the drug release rate and duration can be controlled by designing a morphological feature - namely, mesh thickness - which was achieved by simply regulating the spinning time of the first and third layer. This multilayered electrospun nanofiber mesh fabricated by sequential electrospinning could provide a useful method of controlling drug release behavior over time, which will open new routes for practical applications and stimulate further research in the development of effective drug release carriers. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Acceleration of dermal wound healing by using electrospun curcumin-loaded poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) fibrous mats.

    PubMed

    Fu, Shao-Zhi; Meng, Xiao-Hang; Fan, Juan; Yang, Ling-Lin; Wen, Qing-Lian; Ye, Su-Juan; Lin, Sheng; Wang, Bi-Qiong; Chen, Lan-Lan; Wu, Jing-Bo; Chen, Yue; Fan, Jun-Ming; Li, Zhi

    2014-04-01

    This study prepared a composite scaffold composed of curcumin and poly(ε-caprolactone)-poly(ethylene glycol)-poly(ε-caprolactone) (PCL-PEG-PCL, PCEC) copolymer using coelectrospinning technology. Incorporation of curcumin into the polymeric matrix had an obvious effect on the morphology and dimension of PCEC/curcumin fibers. The results of in vitro anti-oxidant tests and of the cytotoxicity assay demonstrated that the curcumin-loaded PCEC fibrous mats had significant anti-oxidant efficacy and low cytotoxicity. Curcumin could be sustainably released from the fibrous scaffolds. More importantly, in vivo efficacy in enhancing wound repair was also investigated based on a full-thickness dermal defect model for Wistar rats. The results indicated that the PCEC/curcumin fibrous mats had a significant advantage in promoting wound healing. At 21 days post-operation, the dermal defect was basically recovered to its normal condition. A percentage of wound closure reached up to 93.3 ± 5.6% compared with 76.9 ± 4.9% of the untreated control (p < 0.05). Therefore, the as-prepared PCEC/curcumin composite mats are a promising candidate for use as wound dressing.

  12. 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.

  13. Use of lecithin to control fiber morphology in electrospun poly (ɛ-caprolactone) scaffolds for improved tissue engineering applications.

    PubMed

    Coverdale, Benjamin D M; Gough, Julie E; Sampson, William W; Hoyland, Judith A

    2017-10-01

    We elucidate the effects of incorporating surfactants into electrospun poly (ɛ-caprolactone) (PCL) scaffolds on network homogeneity, cellular adherence and osteogenic differentiation. Lecithin was added with a range of concentrations to PCL solutions, which were electrospun to yield functionalized scaffolds. Addition of lecithin yielded a dose-dependent reduction in scaffold hydrophobicity, whilst reducing fiber width and hence increasing specific surface area. These changes in scaffold morphology were associated with increased cellular attachment of Saos-2 osteoblasts 3-h postseeding. Furthermore, cells on scaffolds showed comparable proliferation over 14 days of incubation to TCP controls. Through model-based interpretation of image analysis combined with gravimetric estimates of porosity, lecithin is shown to reduce scaffold porosity and mean pore size. Additionally, lecithin incorporation is found to reduce fiber curvature, resulting in increased scaffold specific elastic modulus. Low concentrations of lecithin were found to induce upregulation of several genes associated with osteogenesis in primary mesenchymal stem cells. The results demonstrate that functionalization of electrospun PCL scaffolds with lecithin can increase the biocompatibility and regenerative potential of these networks for bone tissue engineering applications. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2865-2874, 2017. © 2017 The Authors Journal of Biomedical Materials Research Part A Published by Wiley Periodicals, Inc.

  14. 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.

  15. 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

  16. Effect of moisture on electrospun nanofiber composites of poly(vinyl alcohol) and cellulose nanocrystals.

    PubMed

    Peresin, Maria S; Habibi, Youssef; Vesterinen, Arja-Helena; Rojas, Orlando J; Pawlak, Joel J; Seppälä, Jukka V

    2010-09-13

    The effect of humidity on the morphological and thermomechanical properties of electrospun poly(vinyl alcohol) (PVA) fiber mats reinforced with cellulose nanocrystals (CNs) was investigated. Scanning electron microscopy (SEM) images revealed that the incorporation of CNs improved the morphological stability of the composite fibers even in high humidity environments. Thermal and mechanical properties of the electrospun fiber mats were studied by using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and large deformation tensile tests under controlled humidity and temperatures. The balance between the moisture-induced plasticization and the reinforcing effect of rigid CN particles was critical in determining the thermomechanical behaviors of the electrospun fiber mats. Results indicated that the stabilizing effect of the CNs in the PVA matrix might be compromised by water absorption, disrupting the hydrogen bonding within the structure. The amount of this disruption depended on the surrounding humidity and the CN loading. The reduction in tensile strength of neat PVA fiber mats as they were conditioned from low relative humidity (10% RH) to high relative humidity (70% RH) was found to be about 80%, from 1.5 to 0.4 MPa. When the structure was reinforced with CNs, the reduction in strength was limited to 40%, from 2 to 0.8 MPa over the same range in relative humidity. More importantly, the CN-loaded PVA fiber mats showed a reversible recovery in mechanical strength after cycling the relative humidity. Finally, humidity treatments of the composite PVA fiber mats induced significant enhancement of their strength as a result of the adhesion between the continuous matrix and the CNs.

  17. 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.

  18. 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

  19. Anisotropic poly (glycerol sebacate)-poly (ϵ-caprolactone) electrospun fibers promote endothelial cell guidance.

    PubMed

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

    2014-12-17

    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 exhibited higher proliferation compared to those cultures on randomly oriented fibrous scaffolds. Furthermore, the endothelial cells reorganized in response to the topographical features of aligned scaffolds forming highly organized cellular constructs. Thus, topographical contact guidance, provided by aligned PGS-PCL scaffolds, is envisioned to be useful in developing cellular structures for vascular tissue engineering.

  20. Three-dimensional functional human neuronal networks in uncompressed low-density electrospun fiber scaffolds.

    PubMed

    Jakobsson, Albin; Ottosson, Maximilian; Zalis, Marina Castro; O'Carroll, David; Johansson, Ulrica Englund; Johansson, Fredrik

    2017-01-05

    We demonstrate an artificial three-dimensional (3D) electrical active human neuronal network system, by the growth of brain neural progenitors in highly porous low density electrospun poly-ε-caprolactone (PCL) fiber scaffolds. In neuroscience research cell-based assays are important experimental instruments for studying neuronal function in health and disease. Traditional cell culture at 2D-surfaces induces abnormal cell-cell contacts and network formation. Hence, there is a tremendous need to explore in vivo-resembling 3D neural cell culture approaches. We present an improved electrospinning method for fabrication of scaffolds that promote neuronal differentiation into highly 3D integrated networks, formation of inhibitory and excitatory synapses and extensive neurite growth. Notably, in 3D scaffolds in vivo-resembling intermixed neuronal and glial cell network were formed, whereas in parallel 2D cultures a neuronal cell layer grew separated from an underlying glial cell layer. Hence, the use of the 3D cell assay presented will most likely provide more physiological relevant results.

  1. Core-Shell Fibers Electrospun from Phase-Separated Blend Solutions: Fiber Formation Mechanism and Unique Energy Dissipation for Synergistic Fiber Toughness.

    PubMed

    Wang, Chi; Hsiue, Ting-Ting

    2017-09-11

    Through single-tube electrospinning, the biodegradable core-shell fibers of poly(3-hydroxybutyrate) (PHB) and poly(d,l-lactic acid) (PDLLA) were obtained from blend solutions with different compositions at a total polymer concentration of 7 wt %. Regardless whether PHB is the major or minor component (PHB/PDLLA = 90/10, 75/25, 50/50, and 25/75 wt. ratio), these phase-separated solutions all yielded core-shell fibers with PHB as core and PDLLA as shell. A new scenario of core-shell fiber formation was proposed on the basis of the relative magnitude of the intrinsic relaxation rate of fluids and external extension rate during electrospinning. The effects of blend compositions on the morphologies of the Taylor cone, whipping jet, and as-spun fibers were investigated. The diameters of core-shell fibers can be tailored by simply varying the PHB/PDLLA ratios. Two scaling laws describing the apparent viscosity (ηo) dependence of the outer fiber diameter (dfo) and core fiber diameter (dfc) were derived. That is, dfo ∼ ηo(0.38) and dfc ∼ ηo(0.86). The microstructures of the as-spun fibers were determined by differential scanning calorimetry, Fourier transform infrared spectroscopy, and synchrotron wide-angle and small-angle X-ray scatterings. Results showed that the PDLLA component was in the amorphous state, and the crystallizability of PHB component remained unchanged, except the amorphous 10/90 fibers electrospun from a miscible solution state. The synergistic mechanical properties of the core-shell fibers were obtained, along with the ductile PDLLA shell enclosing the brittle PHB core. The enhanced toughness was attributed to the fragmentation of the brittle PHB core and necking fracture of the ductile PDLLA shell, which served as an effective route for energy dissipation. Compared with the neat PHB fiber, the 90/10 and 75/25 core-shell fibers possessed larger elastic moduli, which was attributed to the high PHB crystal orientation in their core sections despite

  2. Photocatalytic antibacterial effect of ZnO nanoparticles into coaxial electrospun PCL fibers to prevent infections from skin injuries

    NASA Astrophysics Data System (ADS)

    Prado-Prone, G.; Silva-Bermúdez, P.; García-Macedo, J. A.; Almaguer-Flores, A.; Ibarra, C.; Velasquillo-Martínez, C.

    2017-02-01

    Antibacterial studies of inorganic nanoparticles (nps) have become important due to the increased bacterial resistance against antibiotics. We used Zinc oxide nanoparticles (ZnO nps), which possess excellent photocatalytic properties with a wide band gap (Eg), are listed as "generally recognized as safe" by the Food and Drug Administration (FDA) and have shown antibacterial activity (AA) against many bacterial strains. The AA of ZnO nps is partly attributed to the production of Reactive Oxygen Species (ROS) by photocatalysis. When ZnO nps in aqueous media are illuminated with an energy fibers obtained by electrospinning technique. To optimize the use of ZnO nps concentration, we developed coreshell coaxial electrospun fibers where the core corresponded to PCL and the shell to a mixture of ZnO nps/PCL. Thus, ZnO nps were only dispersed on the surface of the fibers increasing its superficial contact area. We evaluated the AA against E. coli of different electrospun ZnO nps/PCL fibers under two different conditions: UVA pre-illumination and darkness. Preliminary results suggest that the AA against E. coli is better when electrospun ZnO nps/PCL were preilluminated with UVA than under darkness conditions.

  3. Promoted regeneration of mature blood vessels by electrospun fibers with loaded multiple pDNA-calcium phosphate nanoparticles.

    PubMed

    Chen, Fang; Wan, Huiying; Xia, Tian; Guo, Xueqin; Wang, Huan; Liu, Yaowen; Li, Xiaohong

    2013-11-01

    Vascularization is one of the capital challenges in the establishment of tissue engineering constructs and recovery of ischemic and wounded tissues. The aim of this study was to assess electrospun fibers with loadings of multiple pDNA to allow a localized delivery for an efficient regeneration of mature blood vessels. To induce sufficient protein expression, a reverse microemulsion process was adopted to load pDNA into calcium phosphate nanoparticles (CP-pDNA), which were electrospun into fibers to achieve a sustained release for 4 weeks. Compared with pDNA-infiltrated fibers, the localized and gradual release of pDNA facilitated cell proliferation, gene transfection, and extracellular matrix secretion and enhanced the generation of blood vessels after subcutaneous implantation. Compared with commonly used pDNA polyplexes with poly(ethyleneimine), CP-pDNA nanoparticles induced significantly lower cytotoxicity and less inflammation reaction after implantation into animals. Fibers with encapsulated nanoparticles containing plasmids encoding vascular endothelial growth factor (pVEGF) and basic fibroblast growth factors (pbFGF) led to significantly higher density of mature blood vessels than those containing individual plasmid. It is suggested that the integration of CP-pDNA nanoparticles with loadings of multiple plasmids into fibrous scaffolds should provide clinical relevance for therapeutic vascularization, getting fully vascularized in engineered tissues and regeneration of blood vessel substitutes. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. Electrospun modified silica-polyamide nanocomposite as a novel fiber coating.

    PubMed

    Bagheri, Habib; Roostaie, Ali

    2014-01-10

    In the present work, a new solid phase microextraction (SPME) fiber coating based on modified silica-polyamide (PA) nanocomposite was electrospun on a stainless steel wire. Four modified silica-PA nanocomposites together with PA were fabricated by dispersing several typical modified silica nanoparticles in PA polymer solution prior to electrospinning. The surface characteristic of PA nanofibers and modified silica-PA nanocomposites was investigated using scanning electron microscopy (SEM). The homogeneity and the porous surface structure of the modified silica-PA nanocomposites were confirmed by SEM, showing nanofibers diameters lower than 170 nm. The applicability of the new fiber coating was examined by headspace SPME of some selected chlorobenzenes (CBs), as model compounds, from aqueous samples. Subsequently, the extracted analytes were transferred into a gas chromatography (GC) by thermal desorption. Influencing parameters on the morphology of nanocomposites such as type of modified silica nanoparticles and the weight ratio of components were optimized. In addition, effects of different parameters influencing the extraction efficiency including extraction temperature, extraction time, ionic strength, desorption temperature, and desorption time were investigated and optimized. Eventually, the developed method was validated by gas chromatography-mass spectrometry (GC-MS). At the optimum conditions, the relative standard deviation values for a double distilled water spiked with the selected CBs at 100 ng L(-1) were 4-12% (n=3) and the limit of detection for the studied compounds was between 5 and 30 ng L(-1). The calibration curves of analytes were investigated in the range of 50-1000 ng L(-1) and correlation coefficients (R(2)) between 0.9897 and 0.9992 were obtained. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. 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

    2015-08-04

    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.

  6. Sulfonated nanoparticles doped electrospun fibers with bioinspired polynorepinephrine sheath for in vivo solid-phase microextraction of pharmaceuticals in fish and vegetable.

    PubMed

    Qiu, Junlang; Chen, Guosheng; Zhu, Fang; Ouyang, Gangfeng

    2016-07-15

    In this study, the biocompatible copolymer Poly(lactic acid-co-caprolactone) (PLCL) doped with sulfonated γ-Al2O3 nanoparticles was used for electrospun on stainless wires. The electrospun fibers were further sheathed by the self-polymerization of norepinephrine, a catecholamine found both in neurotransmitters and mussel adhesive proteins, to improve the surface hydrophilicity and provide a smooth bio-interface. The modified electrospun fibers on stainless wires were developed as novel custom-made solid-phase microextraction (SPME) fibers. These fibers exhibited much higher extraction efficiency compared to the polydimethylsiloxane (PDMS) fibers, especially to the sulfonamides. The custom-made SPME fibers also showed excellent stability with the relative standard deviations (RSDs) of intra-fiber ranged from 1.98% to 9.86% and RSDs of inter-fiber ranged from 4.36% to 15.6%. Moreover, these fibers were also demonstrated to be anti-biofouling and suitable for in vivo sampling. The custom-made SPME fibers were successfully applied to determine the Pharmaceutical concentrations in living fishes and vegetables. The accuracies were verified by the comparison with liquid extraction and the sensitivities were demonstrated to be satisfying with the limits of detection (LODs) ranged from 0.16ng/g to 5.35ng/g in fish muscle and 0.02ng/g to 8.02ng/g in vegetable stem.

  7. Controlled protein release from electrospun biodegradable fiber mesh composed of poly(epsilon-caprolactone) and poly(ethylene oxide).

    PubMed

    Kim, Taek Gyoung; Lee, Doo Sung; Park, Tae Gwan

    2007-06-29

    A blend mixture of poly(epsilon-caprolactone) (PCL) and poly(ethylene oxide) (PEO) was electrospun to produce fibrous meshes that could release a protein drug in a controlled manner. Various biodegradable polymers, such as poly(l-lactic acid) (PLLA), poly(epsilon-caprolactone) (PCL), and poly(d,l-lactic-co-glycolic acid) (PLGA) were dissolved, along with PEO and lysozyme, in a mixture of chloroform and dimethylsulfoxide (DMSO). The mixture was electrospun to produce lysozyme loaded fibrous meshes. Among the polymers, the PCL/PEO blend meshes showed good morphological stability upon incubation in the buffer solution, resulting in controlled release of lysozyme over an extended period with reduced initial bursts. With varying the PCL/PEO blending ratio, the release rate of lysozyme from the corresponding meshes could be readily modulated. The lysozyme release was facilitated by increasing the amount of PEO, indicating that entrapped lysozyme was mainly released out by controlled dissolution of PEO from the blend meshes. Lysozyme released from the electrospun fibers retained sufficient catalytic activity.

  8. Artificial neural network for modeling the elastic modulus of electrospun polycaprolactone/gelatin scaffolds.

    PubMed

    Vatankhah, Elham; Semnani, Dariush; Prabhakaran, Molamma P; Tadayon, Mahdi; Razavi, Shahnaz; Ramakrishna, Seeram

    2014-02-01

    Scaffolds for tissue engineering (TE) require the consideration of multiple aspects, including polymeric composition and the structure and mechanical properties of the scaffolds, in order to mimic the native extracellular matrix of the tissue. Electrospun fibers are frequently utilized in TE due to their tunable physical, chemical, and mechanical properties and porosity. The mechanical properties of electrospun scaffolds made from specific polymers are highly dependent on the processing parameters, which can therefore be tuned for particular applications. Fiber diameter and orientation along with polymeric composition are the major factors that determine the elastic modulus of electrospun nano- and microfibers. Here we have developed a neural network model to investigate the simultaneous effects of composition, fiber diameter and fiber orientation of electrospun polycaprolactone/gelatin mats on the elastic modulus of the scaffolds under ambient and simulated physiological conditions. The model generated might assist bioengineers to fabricate electrospun scaffolds with defined fiber diameters, orientations and constituents, thereby replicating the mechanical properties of the native target tissue.

  9. Electrospun Collagen/Silk Tissue Engineering Scaffolds: Fiber Fabrication, Post-Treatment Optimization, and Application in Neural Differentiation of Stem Cells

    NASA Astrophysics Data System (ADS)

    Zhu, Bofan

    Biocompatible scaffolds mimicking the locally aligned fibrous structure of native extracellular matrix (ECM) are in high demand in tissue engineering. In this thesis research, unidirectionally aligned fibers were generated via a home-built electrospinning system. Collagen type I, as a major ECM component, was chosen in this study due to its support of cell proliferation and promotion of neuroectodermal commitment in stem cell differentiation. Synthetic dragline silk proteins, as biopolymers with remarkable tensile strength and superior elasticity, were also used as a model material. Good alignment, controllable fiber size and morphology, as well as a desirable deposition density of fibers were achieved via the optimization of solution and electrospinning parameters. The incorporation of silk proteins into collagen was found to significantly enhance mechanical properties and stability of electrospun fibers. Glutaraldehyde (GA) vapor post-treatment was demonstrated as a simple and effective way to tune the properties of collagen/silk fibers without changing their chemical composition. With 6-12 hours GA treatment, electrospun collagen/silk fibers were not only biocompatible, but could also effectively induce the polarization and neural commitment of stem cells, which were optimized on collagen rich fibers due to the unique combination of biochemical and biophysical cues imposed to cells. Taken together, electrospun collagen rich composite fibers are mechanically strong, stable and provide excellent cell adhesion. The unidirectionally aligned fibers can accelerate neural differentiation of stem cells, representing a promising therapy for neural tissue degenerative diseases and nerve injuries.

  10. 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.

  11. 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.

  12. Electrospun PLGA Fibers Incorporated with Functionalized Biomolecules for Cardiac Tissue Engineering

    PubMed Central

    Yu, Jiashing; Lee, An-Rei; Lin, Wei-Han; Lin, Che-Wei; Wu, Yuan-Kun

    2014-01-01

    Structural similarity of electrospun fibers (ESFs) to the native extracellular matrix provides great potential for the application of biofunctional ESFs in tissue engineering. This study aimed to synthesize biofunctionalized poly (L-lactide-co-glycolide) (PLGA) ESFs for investigating the potential for cardiac tissue engineering application. We developed a simple but novel strategy to incorporate adhesive peptides in PLGA ESFs. Two adhesive peptides derived from laminin, YIGSR, and RGD, were covalently conjugated to poly-L-lysine, and then mingled with PLGA solution for electrospinning. Peptides were uniformly distributed on the surface and in the interior of ESFs. PLGA ESFs incorporated with YIGSR or RGD or adsorbed with laminin significantly enhanced the adhesion of cardiomyocytes isolated from neonatal rats. Furthermore, the cells were found to adhere better on ESFs compared with flat substrates after 7 days of culture. Immunofluorescent staining of F-actin, vinculin, a-actinin, and N-cadherin indicated that cardiomyocytes adhered and formed striated α-actinin better on the laminin-coated ESFs and the YIGSR-incorporated ESFs compared with the RGD-incorporated ESFs. The expression of α-myosin heavy chain and β-tubulin on the YIGSR-incorporated ESFs was significantly higher compared with the expression level on PLGA and RGD-incorporated samples. Furthermore, the contraction of cardiomyocytes was faster and lasted longer on the laminin-coated ESFs and YIGSR-incorporated ESFs. The results suggest that aligned YIGSR-incorporated PLGA ESFs is a better candidate for the formation of cardiac patches. This study demonstrated the potential of using peptide-incorporated ESFs as designable-scaffold platform for tissue engineering. PMID:24471778

  13. Fabrication of SiC mat by radiation processing

    NASA Astrophysics Data System (ADS)

    Kang, Phil-Hyun; Jeun, Joon-Pyo; Seo, Dong-Kwon; Nho, Young-Chang

    2009-07-01

    Silicon carbide (SiC) exhibits many important properties, such as high intrinsic strength, stiffness, and high temperature stability. Therein, it is considered to be one of the most promising candidates for reinforcement of advanced ceramic matrix composites. The use of preceramic polymers presents the possibility of solving the intricacies involved in obtaining a new generation of ceramic materials. In this study, a radiation processing method was used to fabricate a cured polycarbosilane mat as a preceramic polymer. The polycarbosilane mat was cured by electron beam (e-beam) irradiation up to 10 MGy in an inert gas atmosphere. Next, the e-beam-cured PCS mat, as green fiber, was carbonized to produce the SiC mat. The conversion process of the PCS mat into the SiC mat was investigated by SEM, FT-IR, XRD, and TGA. According to FT-IR analysis, the Si-H peak intensity was observed to decrease as the polymer structure changed from polycarbosilane to SiC. The XRD patterns of SiC showed the diffraction peaks at (1 1 1), (2 2 0), and (3 1 1) which indicated the emergence of β-SiC. TGA curve shows that weight percent of residue of electrospun PCS mat, e-beam-cured PCS mat and pyrolyzed SiC mat up to 1000 °C were 72.5%, 88.3%, and 99.2%, respectively.

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

    PubMed

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

    2014-02-01

    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.

  15. 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

  16. Electrospun micro/nanofibrous conduits composed of poly(epsilon-caprolactone) and small intestine submucosa powder for nerve tissue regeneration.

    PubMed

    Hong, Soongee; Kim, Geunhyung

    2010-08-01

    Three-dimensional biocompatible and biodegradable scaffolds play important roles in tissue engineering. In this study, fibrous mats composed of electrospun poly(epsilon-caprolactone) (PCL)/small intestine submucosa (SIS) tubes were fabricated with a high degree of longitudinal alignment as a conduit for peripheral nerves. Fourier transform infrared analyses of electrospun PCL/SIS mats with various amounts of SIS showed that the SIS was well embedded within the PCL matrix. The diameter of the PCL/SIS fibers with the 3 wt % of SIS in the PCL solution decreased 40% relative to that of pure PCL fibers due to increased electrical conductivity and decreased surface tension. PCL/SIS (3 wt %) electrospun mats exhibited various synergistic effects, including stronger mechanical properties (Young's modulus = more than 80%) and enhanced hydrophilicity (water contact angle at 30 min = 54 degrees ) relative to pure PCL (water contact angle at 30 min = 142 degrees ). Cell attachment and proliferation experiments demonstrated that the interactions between nerve cells (PC-12) and the PCL/SIS conduits were more favorable than those between PC-12 cells and a pure PCL conduit. This study contributes to the understanding of the effects of including SIS in electrospun composite mats. The ability to fabricate highly aligned tubes of PCL/SIS with appropriate mechanical properties and cellular interactions shows great potential for the design of nerve regeneration conduits.

  17. Surface grafting of electrospun fibers using ATRP and RAFT for the control of biointerfacial interactions.

    PubMed

    Ameringer, Thomas; Ercole, Francesca; Tsang, Kelly M; Coad, Bryan R; Hou, Xueliang; Rodda, Andrew; Nisbet, David R; Thissen, Helmut; Evans, Richard A; Meagher, Laurence; Forsythe, John S

    2013-12-01

    The ability to present signalling molecules within a low fouling 3D environment that mimics the extracellular matrix is an important goal for a range of biomedical applications, both in vitro and in vivo. Cell responses can be triggered by non-specific protein interactions occurring on the surface of a biomaterial, which is an undesirable process when studying specific receptor-ligand interactions. It is therefore useful to present specific ligands of interest to cell surface receptors in a 3D environment that minimizes non-specific interactions with biomolecules, such as proteins. In this study, surface-initiated atom transfer radical polymerization (SI-ATRP) of poly(ethylene glycol)-based monomers was carried out from the surface of electrospun fibers composed of a styrene/vinylbenzyl chloride copolymer. Surface initiated radical addition-fragmentation chain transfer (SI-RAFT) polymerisation was also carried out to generate bottle brush copolymer coatings consisting of poly(acrylic acid) and poly(acrylamide). These were grown from surface trithiocarbonate groups generated from the chloromethyl styrene moieties existing in the original synthesised polymer. XPS was used to characterise the surface composition of the fibers after grafting and after coupling with fluorine functional XPS labels. Bottle brush type coatings were able to be produced by ATRP which consisted of poly(ethylene glycol) methacrylate and a terminal alkyne-functionalised monomer. The ATRP coatings showed reduced non-specific protein adsorption, as a result of effective PEG incorporation and pendant alkynes groups existing as part of the brushes allowed for further conjugation of via azide-alkyne Huisgen 1,3-dipolar cycloaddition. In the case of RAFT, carboxylic acid moieties were effectively coupled to an amine label via amide bond formation. In each case XPS analysis demonstrated that covalent immobilisation had effectively taken place. Overall, the studies presented an effective platform for

  18. 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.

  19. 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.

  20. 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

  1. On the interplay of morphology and electronic conductivity of rotationally spun carbon fiber mats

    NASA Astrophysics Data System (ADS)

    Opitz, Martin; Go, Dennis; Lott, Philipp; Müller, Sandra; Stollenwerk, Jochen; Kuehne, Alexander J. C.; Roling, Bernhard

    2017-09-01

    Carbon-based materials are used as electrode materials in a wide range of electrochemical applications, e.g., in batteries, supercapacitors, and fuel cells. For these applications, the electronic conductivity of the materials plays an important role. Currently, porous carbon materials with complex morphologies and hierarchical pore structures are in the focus of research. The complex morphologies influence the electronic transport and may lead to an anisotropic electronic conductivity. In this paper, we unravel the influence of the morphology of rotationally spun carbon fiber mats on their electronic conductivity. By combining experiments with finite-element simulations, we compare and evaluate different electrode setups for conductivity measurements. While the "bar-type method" with two parallel electrodes on the same face of the sample yields information about the intrinsic conductivity of the carbon fibers, the "parallel-plate method" with two electrodes on opposite faces gives information about the electronic transport orthogonal to the faces. Results obtained for the van-der-Pauw method suggest that this method is not well suited for understanding morphology-transport relations in these materials.

  2. Three-Dimensional Highly Stretchable Conductors from Elastic Fiber Mat with Conductive Polymer Coating.

    PubMed

    Duan, Shasha; Wang, Zhihui; Zhang, Ling; Liu, Jin; Li, Chunzhong

    2017-09-13

    The manufacture of stretchable conductors with well-reserved electrical performance under large-degree deformations via scalable processes remains of great importance. In this work, a highly stretchable 3D conductive framework consisting of a polyurethane fiber mat (PUF) and poly(3,4-ethylenedioxythiophene) (PEDOT) is reported through facile approaches, electrospinning, and in situ interfacial polymerization, which was then backfilled with poly(dimethylsiloxane) to obtain 3D conductors. The excellent stretchability of the 3D conductive network imparted the as-prepared electrode a superior mechanical durability. Moreover, the applied strains can be effectively accommodated by the arrangement and orientation of the fibers resulting in a relatively stable electrical performance with only a 20% increased resistance at 100% stretching. Meanwhile, the resistance of the conductor could remain constant during 2000 bending cycles and showed a slight increase during 100 cycles of 50% stretching. The potential in the applications of large-area stretchable electrodes was demonstrated by the construction of LED arrays with the PUF-based conductors as electrical connections.

  3. 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. Copyright 2010 Elsevier B.V. All rights reserved.

  4. Effect of heat treatment on ZrO 2 -embedded electrospun carbon fibers used for efficient electromagnetic interference shielding

    NASA Astrophysics Data System (ADS)

    Im, Ji Sun; Kim, Jong Gu; Bae, Tae-Sung; Lee, Young-Seak

    2011-10-01

    ZrO 2 -embedded carbon fibers were prepared for use as an electromagnetic interference (EMI) shielding material by electrospinning and heat treatment methods. Structural changes were observed in the ZrO 2 and in the carbon structures by XRD and Raman spectroscopy, respectively. During heat treatment, XRD analysis results revealed a transition from a monoclinic structure to a tetragonal structure in ZrO 2 and a graphitization in the structural formation of carbon fibers was observed by Raman spectroscopy. It was observed that these structural changes in the ZrO 2 and the carbon fibers improved the real and imaginary permittivities by a factor of more than 3.5. The EMI shielding efficiency (SE) improved along with the permittivity with higher treatment temperatures and greater amounts of embedded ZrO 2 ; the highest average EMI SE achieved was 31.79 dB in 800-8500 MHz. The heat treatment played an important role in the improvements in the permittivity and in the EMI SE because of the heat-induced structural changes of the ZrO 2 -embedded electrospun carbon fibers. We suggest that the EMI shielding of the fibers is primarily due to the absorption of electromagnetic waves, which prevents secondary EMI by reflection of electromagnetic waves.

  5. Mulching effects of plant fiber and plant fiber-polyester mats combined with fertilizer on loblslly pine seedlings

    Treesearch

    James D. Haywood; John A. Youngquist

    1991-01-01

    In this preliminary study, several mattings, combined with and without fertilizer application, were tested around newly planted loblolly, pine (Pinus taeda L.) seedlings. After 9 months in the field, jute- polyester and jute mats had similar survival rates relitive to controls, but hemlock-po1yvester mats had depressed survival when used in...

  6. Pectinate nanofiber mat with high absorbency and antibacterial activity: A potential superior wound dressing to alginate and chitosan nanofiber mats.

    PubMed

    Chen, Sainan; Cui, Sisi; Hu, Junli; Zhou, Yifa; Liu, Yichun

    2017-10-15

    Polysaccharides including pectin, alginate and chitosan are fabricated into dressings of micrometer-scaled architecture (micro- fiber or particle) and widely applied in wound treatments clinically. This work characterized and compared the properties of electrospun nanofibrous dressings of these polysaccharides. We found that although the three polysaccharide nanofiber mats had comparable mechanical strength and vapour permeability, the pectinate nanofiber mat could absorb 1.2 times and 3.6 times more exudates than the alginate and chitosan nanofiber mats, respectively, within less time. Moreover, the pectinate nanofiber mat showed much higher antibacterial activity (73.1%) than the alginate and chitosan nanofiber mats (11.8% and 17.1%, respectively). Further examinations demonstrated that the superior absorbency and antibacterial activity of the pectinate nanofiber mat were associated with the moderate extent of swelling of pectinate nanofibers under hydrated conditions. All these results suggest that the pectinate nanofiber mat might be a superior wound dressing to the alginate and chitosan nanofiber mats. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  8. Superhydrophobic films of electrospun fibers with multiple-scale surface morphology.

    PubMed

    Lim, Jong-Min; Yi, Gi-Ra; Moon, Jun Hyuk; Heo, Chul-Joon; Yang, Seung-Man

    2007-07-17

    Superhydrophobic nanofiber films were created from electrospun nanofibers with undulated surfaces at multiple scales in micrometers and nanometers. The electrospun nanofibers were produced out of aqueous solutions which contained water-soluble polymers and different colloids: monodisperse silica or polystyrene microspheres for larger particles and monodisperse silica nanoparticles for smaller particles. Various types of fibrous films were produced depending on the properties of the dispersing medium, the effects of additives, and the compositions of the bidisperse colloids. When polystyrene microspheres were used as sacrificial templates, macropores were left behind in the nanofibers during the removal of polystyrene microspheres by calcination. The nonwoven films of electrospun nanofibers, which were decorated with silica microspheres or macropores, could be continuously produced with considerable ease under a relatively wide range of operating conditions. The surface properties of the films were characterized by contact angle measurement and an X-ray photoelectron spectrometer. Through the surface modification of the electrospun nanofibers with fluorinated silane coupling agents, superhydrophobic surfaces with low sliding angles were successfully prepared.

  9. 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.

  10. A multipreferred fiber orientation constitutive model for fiber mat-reinforced thermoplastics with a random orientation applied to the stamp thermohydroforming process

    NASA Astrophysics Data System (ADS)

    Zampaloni, Michael A.

    This work focuses on the development of a constitutive relationship for the modeling of a multi-preferred fiber orientation sheet that has several different primary fiber orientations, none of which are necessarily mutually perpendicular prior to, or during, deformation. One of the goals was to develop the constitutive relationship for the deformation behavior of the fiber mat reinforced thermoplastics with a random orientation, a material that is starting to gain in popularity but has not been extensively investigated. Two different types of mat fiber reinforced material were investigated; one a continuous fiber mat and one a chopped fiber mat, both with a polypropylene matrix. Both materials were characterized through a series of squeeze flow and uniaxial tensile tests to determine the preferred fiber orientations as well as the material properties. The constitutive model was implemented through a user-subroutine into the commercial finite element analysis code ABAQUS/Explicit and the numerical results were validated against experimental stamping results. Overall, the multi-preferred fiber orientation constitutive relationship was able to accurately capture the material instabilities that occurred during the stamping process. Since the mat fiber reinforced materials have not been extensively investigated this research creates one of the building blocks that can be used to develop more accurate models in the future. With the addition of a constitutive relationship for the interaction between the layers, this single layer model could be expanded into a constitutive relationship for the full sheet. In addition to the constitutive modeling aspect of this work there is also an experimental portion that deals with the development, design, build and verification of a new processing method for the shaping and forming of fiber reinforced thermoplastic materials, stamp thermo-hydroforming. Experimentation demonstrated that the process provides a 7--10 percent increase in

  11. Tunable release of multiclass anti-HIV drugs that are water-soluble and loaded at high drug content in polyester blended electrospun fibers

    PubMed Central

    Carson, Daniel; Jiang, Yonghou; Woodrow, Kim

    2015-01-01

    Objectives Sustained release of small molecule hydrophilic drugs at high doses remains difficult to achieve from electrospun fibers and limits their use in clinical applications. Here we investigate tunable release of several water-soluble anti-HIV drugs from electrospun fibers fabricated with blends of two biodegradable polyesters. Methods Drug-loaded fibers were fabricated by electrospinning using ratios of PCL and PLGA. Fiber morphology was imaged using SEM, and DSC was used to measure thermal properties. HPLC was used to measure drug loading and release from fibers. Cytotoxicity and antiviral activity of drug-loaded fibers were measured in an in vitro cell culture assay. Results We show programmable release of hydrophilic antiretroviral drugs loaded up to 40 wt%. Incremental tuning of highly-loaded drug fibers within 24 hours or >30 days was achieved by controlling the ratio of PCL and PLGA. Fiber compositions containing higher PCL content yielded greater burst release whereas fibers with higher PLGA content resulted in greater sustained release kinetics. We also demonstrated that our drug-loaded fibers are safe and can sustain inhibition of HIV in vitro. Conclusions These data suggest that we were able to overcome current limitations associated with sustained release of small hydrophilic drugs at clinically relevant doses. We expect that our system represents an effective strategy to sustain delivery of water-soluble molecules that will benefit a variety of biomedical applications. PMID:26286184

  12. 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

  13. Synthesis and characterization of magnetic diphase ZnFe 2O 4/γ-Fe 2O 3 electrospun fibers

    NASA Astrophysics Data System (ADS)

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

    2011-08-01

    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 phase composition, particle size and magnetic properties have been investigated. Zinc ferrite fibers were obtained by calcinating the electrospun fibers in air from 300 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. An increase in 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.

  14. 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.

  15. 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.

  16. 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.

  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. 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.

  19. 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.

  20. 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

  1. Low temperature platinum atomic layer deposition on nylon-6 for highly conductive and catalytic fiber mats

    SciTech Connect

    Mundy, J. Zachary; Shafiefarhood, Arya; Li, Fanxing; Khan, Saad A.; Parsons, Gregory N.

    2016-01-15

    Low temperature platinum atomic layer deposition (Pt-ALD) via (methylcyclopentadienyl)trimethyl platinum and ozone (O{sub 3}) is used to produce highly conductive nonwoven nylon-6 (polyamide-6, PA-6) fiber mats, having effective conductivities as high as ∼5500–6000 S/cm with only a 6% fractional increase in mass. The authors show that an alumina ALD nucleation layer deposited at high temperature is required to promote Pt film nucleation and growth on the polymeric substrate. Fractional mass gain scales linearly with Pt-ALD cycle number while effective conductivity exhibits a nonlinear trend with cycle number, corresponding to film coalescence. Field-emission scanning electron microscopy reveals island growth mode of the Pt film at low cycle number with a coalesced film observed after 200 cycles. The metallic coating also exhibits exceptional resistance to mechanical flexing, maintaining up to 93% of unstressed conductivity after bending around cylinders with radii as small as 0.3 cm. Catalytic activity of the as-deposited Pt film is demonstrated via carbon monoxide oxidation to carbon dioxide. This novel low temperature processing allows for the inclusion of highly conductive catalytic material on a number of temperature-sensitive substrates with minimal mass gain for use in such areas as smart textiles and flexible electronics.

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

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

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

    PubMed

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

    2013-11-12

    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.

  4. 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.

  5. 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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Disc-electrospun cellulose acetate butyrate nanofibers show enhanced cellular growth performances.

    PubMed

    Huang, Chen; Niu, Haitao; Wu, Chunchen; Ke, Qinfei; Mo, Xiumei; Lin, Tong

    2013-01-01

    Cellulose acetate butyrate nanofibers were prepared separately by two electrospinning techniques; a needleless electrospinning using a disc as spinneret and a rotary drum as collector and a conventional needle electrospinning using a rotary drum as collector. Compared to the needle-electrospun nanofibers, the disc-electrospun nanofibers were coarser with a wider diameter distribution. Both fibers had a similar surface morphology and they showed no difference in chemical components, but the disc-electrospun nanofibers were slightly higher in crystallinity. The productivity of disc electrospinning was 150 times larger than that of needle electrospinning. The disc-electrospun nanofiber mats were found to have a three dimensional fibrous structure with an average pore size of 9.1 μm, while the needle-electrospun nanofibers looked more like a two-dimensional sheet with a much smaller average pore size (3.2 μm). Fibroblasts and Schwann cells were cultured on the fibrous matrices to assess the biocompatibility. The disc-electrospun nanofiber webs showed enhanced cellular growth for both fibroblasts and Schwann cells, especially in a long culture period.

  7. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. 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

    2015-09-21

    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.

  9. 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.

  10. Improved cellular infiltration into nanofibrous electrospun cross-linked gelatin scaffolds templated with micrometer sized polyethylene glycol fibers

    PubMed Central

    Skotak, Maciej; Ragusa, Jorge; Gonzalez, Daniela; Subramanian, Anuradha

    2011-01-01

    Gelatin-based nanofibrous scaffolds with a mean fiber diameter of 300 nm were prepared with and without micrometer-sized polyethylene glycol (PEG) fibers that served as sacrificial templates. Upon fabrication of the scaffolds via electrospinning, the gelatin fibers were crosslinked with glutaraldehyde, and the PEG templates were removed using tert-butanol to yield nanofibrous scaffolds with pore diameters ranging from 10 to 100 µm, as estimated with mercury intrusion porosimetry. Non-templated gelatin-based nanofibrous matrices had an average pore size of 1 µm. Fibroblasts were seeded onto both types of the gelatin-based nanfibrous surfaces and cultured for 14 days. For comparative purposes, chitosan-based and polyurethane (PU)-based macroporous scaffolds with pore sizes of 100 µm and 170 µm, respectively, also were included. The number of cells as a function of the depth into the scaffold was judged and quantitatively assessed using nuclei staining. Cell penetration up to a depth of 250 µm and 90 µm was noted in gelatin scaffolds prepared with sacrificial templates and gelatin-only nanofibrous scaffolds. Noticeably, scaffold preparation protocol presented here allowed the structural integrity to be maintained even with high template content (95 %) and can be easily extended towards other classes of electrospun polymer matrices for tissue engineering. PMID:21931195

  11. Impact of electrospun conduit fiber diameter and enclosing pouch pore size on vascular constructs grown within rat peritoneal cavities.

    PubMed

    Bashur, Chris A; Eagleton, Matthew J; Ramamurthi, Anand

    2013-04-01

    The generation of vascular grafts by recruiting autologous cells within the peritoneal cavity has shown promise. However, the microenvironment affects cell differentiation and elastic matrix production. Therefore, this study determined the impact of systematic changes in the average fiber diameter of electrospun poly(ɛ-caprolactone) conduits, and the pore size of pouches used to enclose the conduits, on recruited cells. After 2 weeks in the peritoneal cavity, fibrous capsules formed containing macrophages, α-smooth muscle actin (α-SMA)(+) and SM22α(+) myofibroblastic or smooth muscle like-cells, and what appeared to be mesothelial cells on the outer surfaces. These cells infiltrated and deposited matrix (e.g., collagen, hyaluoronan, and limited elastin) within conduit walls. Constructs enclosed within the largest pore pouches exhibited significantly better tissue generation responses (e.g., better cell infiltration, elongation, and matrix deposition). Additionally, the healing response was impacted by the conduit average fiber diameter, and consequently, the effective pore diameter, with the largest diameter fibers promoting the most positive healing response (e.g., greater total cellularity, extracellular matrix deposition, and α-SMA(+) cells). Six weeks post-intra-aortal grafting, constructs were occluded, but significant remodeling also occurred in the arterial microenvironment. Overall, these results demonstrate the importance of microenvironmental cues on recruited peritoneal cells and the necessity of developing strategies to further improve elastic matrix synthesis.

  12. Mechanical and transport properties of layer-by-layer electrospun composite proton exchange membranes for fuel cell applications.

    PubMed

    Mannarino, Matthew M; Liu, David S; Hammond, Paula T; Rutledge, Gregory C

    2013-08-28

    Composite membranes composed of highly conductive and selective layer-by-layer (LbL) films and electrospun fiber mats were fabricated and characterized for mechanical strength and electrochemical selectivity. The LbL component consists of a proton-conducting, methanol-blocking poly(diallyl dimethyl ammonium chloride)/sulfonated poly(2,6-dimethyl-1,4-phenylene oxide) (PDAC/sPPO) thin film. The electrospun fiber component consists of poly(trimethyl hexamethylene terephthalamide) (PA 6(3)T) fibers in a nonwoven mat of 60-90% porosity. The bare mats were annealed to improve their mechanical properties, which improvements are shown to be retained in the composite membranes. Spray LbL assembly was used as a means for the rapid formation of proton-conducting films that fill the void space throughout the porous electrospun matrix and create a fuel-blocking layer. Coated mats as thin as 15 μm were fabricated, and viable composite membranes with methanol permeabilities 20 times lower than Nafion and through-plane proton selectivity five and a half times greater than Nafion are demonstrated. The mechanical properties of the spray coated electrospun mats are shown to be superior to the LbL-only system and possess intrinsically greater dimensional stability and lower mechanical hysteresis than Nafion under hydrated conditions. The composite proton exchange membranes fabricated here were tested in an operational direct methanol fuel cell. The results show the potential for higher open circuit voltages (OCV) and comparable cell resistances when compared to fuel cells based on Nafion.

  13. Electrospun nanofiber meshes with tailored architectures and patterns as potential tissue-engineering scaffolds.

    PubMed

    Wang, Yazhou; Wang, Guixue; Chen, Liang; Li, Hao; Yin, Tieying; Wang, Bochu; Lee, James C-M; Yu, Qingsong

    2009-03-01

    Using a stainless steel mesh as a template collector, electrospun nanofiber meshes with well-tailored architectures and patterns were successfully prepared from biodegradable poly (epsilon-caprolactone) (PCL). It was found that the resulting PCL nanofiber (NF) meshes had similar topological structures to that of the template stainless steel mesh. Such PCL nanofiber meshes (NF meshes) had improved the tensile strength with Young's modulus of 62.7 +/- 5.3 MPa, which is >40% higher than the modulus of 44 +/- 5.7 MPa as measured with the corresponding randomly oriented PCL nanofiber mats (RNF mat). On the other hand, the ultimate strain (87.30%) of the PCL NF meshes was distinctly lower than that of the PCL RNF mats (146.46%). To the best of our knowledge, this is the first time that the mechanical properties of nanofiber meshes with tailored architectures and patterns were studied and reported. When cultured with a mouse osteoblastic cell line (MC3T3-E1), the electrospun PCL NF meshes gave a much higher proliferation rate as compared with the randomly oriented PCL RNF mats. More importantly, it was found that the cells grew and elongated along the fiber orientation directions, and the resulted cellular organization and distribution mimicked the topological structures of the PCL NF meshes. These results indicated that the electrospun nanofiber scaffolds with tailored architectures and patterns hold potential for engineering functional tissues or organs, where an ordered cellular organization is essential.

  14. Model development and application design of fiber mat used for turbid runoff treatment.

    PubMed

    Yu, Jianghua; Yu, Haixia; Kim, Youngchul

    2013-01-01

    Performance of a synthetic-fibre mat was investigated for the treatment of high-turbidity runoff. The impact of different operating parameters, such as hydraulics (flow rate and exchange rate), density current due to temperature and turbidity differences, mat conditions (thickness and number) and particle size were studied. The experimental results showed that increasing the mat thickness and number enhanced turbidity removal. The density current showed significant inverse effect on mat performance. Turbidity removal decreased with the increasing flow rate and exchange rate. Particle size also indicated an influence on removal efficiency. Predictive correlations for turbidity removal efficiency and mat design were established using dimensionless groups based on the experiment. The simulation results indicated that the predicted values correlated with the experimental ones significantly. Finally, the application design process was demonstrated.

  15. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Kinetics and Antioxidant Capacity of Proanthocyanidins Encapsulated in Zein Electrospun Fibers by Cyclic Voltammetry.

    PubMed

    Wang, Hualin; Hao, Lilan; Niu, Baicheng; Jiang, Suwei; Cheng, Junfeng; Jiang, Shaotong

    2016-04-20

    The proanthocyanidins encapsulated in zein (zein-PA) fibers was via electrospinning technique. The kinetics and antioxidant capacity of PA from zein fibers was investigated by cyclic voltammetry. Circular dichroism was used to investigate the secondary structure change of zein and its influence on the shape of fibers. The addition of PA caused a significant increase in viscosity and made fibers wider. These hydrogen bonds between zein and PA molecules would favor the α-helix change and decrease the β-folds of zein in electrospinning solutions, leading to a round-shaped tendency of fibers and enhancing the thermal properties slightly. Zein-PA fibers showed high encapsulation efficiency close to 100%, and the encapsulated PA retained its antioxidant capacity in fibers. Zein-PA fibers showed a good controlled release toward PA, and the predominant release of PA from fibers was Fickian diffusion, which could be well described by first-order model and Hixson-Crowell model.

  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. Synthesis and application of highly ordered arrays of TiO2 rods grown on electrospun PVDF fibers

    NASA Astrophysics Data System (ADS)

    Zhang, Zhi-Guang; Liu, Hui; Zhang, Bin; Zhang, Jun; Liu, Rong-Zhan; Ning, Xin; Long, Yun-Ze

    2017-07-01

    This paper reports the controlled synthesis of highly ordered arrays of rutile TiO2 rods with tunable size and properties on electrospun PVDF Fibers by using a low-temperature hydrothermal growth strategy. Well-defined, highly ordered, vertically oriented TiO2 rod arrays covering on the PVDF fibers backbone were obtained. In order to study the morphology-dependent optical and photocatalytic properties of the hierarchical composites, the hydrothermal treatment time was varied, resulting in rime-like (6 h) and rod bundles (4 h and 10 h) morphologies. By contrast, the crystallinity, grain size and optical properties of the sample depended on the hydrothermal treatment time. After being irradiated for 600 min with an 18 W UV lamp, the photocatalytic efficiency of rhodamine B for the sample hydrothermal treated for 4 h, 6 h and 10 h was about 28%, 37% and 85%, respectively. A slight decrease in the photodegradation efficiency can be detected after five times recycled experiments. Moreover, further study indicates that the rime-like branched structure promote photocatalytic efficiency.

  19. Multipurpose tenofovir disoproxil fumarate electrospun fibers for the prevention of HIV-1 and HSV-2 infections in vitro.

    PubMed

    Tyo, Kevin M; Vuong, Hung R; Malik, Danial A; Sims, Lee B; Alatassi, Houda; Duan, Jinghua; Watson, Walter H; Steinbach-Rankins, Jill M

    2017-10-05

    Sexually transmitted infections affect hundreds of millions of people worldwide. Both human immunodeficiency virus (HIV-1 and -2) and herpes simplex virus-2 (HSV-2) remain incurable, urging the development of new prevention strategies. While current prophylactic technologies are dependent on strict user adherence to achieve efficacy, there is a dearth of delivery vehicles that provide discreet and convenient administration, combined with prolonged-delivery of active agents. To address these needs, we created electrospun fibers (EFs) comprised of FDA-approved polymers, poly(lactic-co-glycolic acid) (PLGA) and poly(DL-lactide-co-ε-caprolactone) (PLCL), to provide sustained-release and in vitro protection against HIV-1 and HSV-2. PLGA and PLCL EFs, incorporating the antiretroviral, tenofovir disoproxil fumarate (TDF), exhibited sustained-release for up to 4 weeks, and provided complete in vitro protection against HSV-2 and HIV-1 for 24h and 1 wk, respectively, based on the doses tested. In vitro cell culture and EpiVaginal tissue tests confirmed the safety of fibers in vaginal and cervical cells, highlighting the potential of PLGA and PLCL EFs as multipurpose next-generation drug delivery vehicles. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Evaluation of oriented electrospun fibers for periosteal flap regeneration in biomimetic triphasic osteochondral implant.

    PubMed

    Liu, Xudong; Liu, Shen; Liu, Shenghe; Cui, Wenguo

    2014-10-01

    Osteochondral defects represent a serious clinical problem. Although the cell-scaffold complexes have been reported to be effective for repairing osteochondral defects, a periosteal flap is frequently needed to arrest leakage of the implanted cells into the defect and to contribute to the secretion of cytokines to stimulate cartilage repair. The electrospun mesh mimicking the function of the flap assists tissue regeneration by preventing cell leakage and merits favorable outcomes in the cartilaginous region. In this study, an oriented poly(ε-caprolactone) (PCL) fibrous membrane (OEM) was fabricated by electrospinning as a periosteal scaffold and then freeze-dried with a collagen type I and hyaluronic acid cartilage scaffold (CH) and finally, freeze-dried with a tricalcium phosphate (TCP) bone substratum. Scanning electron microscopic images show obvious microstructure formation of the trilayered scaffolds, and electrospun fibrous membranes have an oriented fibrous network structure for the periosteal phase. Also shown are opened and interconnected pores with well designed three-dimensional structure, able to be bound in the CH (chondral phase) and TCP (osseous phase) scaffolds. In vitro results showed that the OEM can promote the orientation of bone marrow mesenchymal stem cell (BMSCs) and BMSCs can penetrate into the CH and TCP. After successfully combining the BMSCs, the tissue-engineered cartilage which contained the OEM and TCP complex was successfully used to regenerate the osteochondral defects in the rabbit model with greatly improved repair effects.

  1. 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

  2. Study of Polydiacetylene-Poly (Ethylene Oxide) Electrospun Fibers Used as Biosensors

    PubMed Central

    Alam, A K M Mashud; Yapor, Janet P.; Reynolds, Melissa M.; Li, Yan Vivian

    2016-01-01

    Polydiacetylene (PDA) is an attractive conjugated material for use in biosensors due to its unique characteristic of undergoing a blue-to-red color change in response to external stimuli. 10,12-Pentacosadiynoic acid (PCDA) and poly (ethylene oxide) (PEO) were used in this study to develop fiber composites via an electrospinning method at various mass ratios of PEO to PCDA, solution concentrations, and injection speeds. The PEO-PDA fibers in blue phase were obtained via photo-polymerization upon UV-light irritation. High mass ratios of PEO to PCDA, low polymer concentrations of spinning solution, and low injection speeds promoted fine fibers with small diameters and smooth surfaces. The colorimetric transition of the fibers was investigated when the fibers were heated at temperatures ranging from 25 °C to 120 °C. A color switch from blue to red in the fibers was observed when the fibers were heated at temperatures greater than 60 °C. The color transition was more sensitive in the fibers made with a low mass ratio of PEO to PCDA due to high fraction of PDA in the fibers. The large diameter fibers also promoted the color switch due to high reflectance area in the fibers. All of the fibers were analyzed using Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) and compared before and after the color change occurred. The colorimetric transitional mechanism is proposed to occur due to conformational changes in the PDA macromolecules. PMID:28773326

  3. Study of Polydiacetylene-Poly (Ethylene Oxide) Electrospun Fibers Used as Biosensors.

    PubMed

    Alam, A K M Mashud; Yapor, Janet P; Reynolds, Melissa M; Li, Yan Vivian

    2016-03-16

    Polydiacetylene (PDA) is an attractive conjugated material for use in biosensors due to its unique characteristic of undergoing a blue-to-red color change in response to external stimuli. 10,12-Pentacosadiynoic acid (PCDA) and poly (ethylene oxide) (PEO) were used in this study to develop fiber composites via an electrospinning method at various mass ratios of PEO to PCDA, solution concentrations, and injection speeds. The PEO-PDA fibers in blue phase were obtained via photo-polymerization upon UV-light irritation. High mass ratios of PEO to PCDA, low polymer concentrations of spinning solution, and low injection speeds promoted fine fibers with small diameters and smooth surfaces. The colorimetric transition of the fibers was investigated when the fibers were heated at temperatures ranging from 25 °C to 120 °C. A color switch from blue to red in the fibers was observed when the fibers were heated at temperatures greater than 60 °C. The color transition was more sensitive in the fibers made with a low mass ratio of PEO to PCDA due to high fraction of PDA in the fibers. The large diameter fibers also promoted the color switch due to high reflectance area in the fibers. All of the fibers were analyzed using Fourier transform infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) and compared before and after the color change occurred. The colorimetric transitional mechanism is proposed to occur due to conformational changes in the PDA macromolecules.

  4. 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

  5. Electrospun chitosan-graft-poly (ε -caprolactone)/poly (ε-caprolactone) cationic nanofibrous mats as potential scaffolds for skin tissue engineering.

    PubMed

    Chen, Honglin; Huang, Jin; Yu, Jiahui; Liu, Shiyuan; Gu, Ping

    2011-01-01

    This research is aimed to develop cationic nanofibrous mats with improved cellular adhesion profiles and stability of three-dimensional fibrous structure as potential scaffolds for skin tissue engineering. Firstly, amino-remained chitosan-graft-poly (ɛ-caprolactone) (CS-g-PCL) was synthesized with a facile one-step manner by grafting ɛ-caprolactone oligomers onto the hydroxyl groups of CS via ring-opening polymerization by using methanesulfonic acid as solvent and catalyst. And then, CS-g-PCL/PCL nanofibrous mats were obtained by electrospinning of CS-g-PCL/PCL mixed solution. Scanning electron microscopy (SEM) images showed that the morphologies and diameters of the nanofibers were mainly affected by the weight ratio of CS-g-PCL to PCL. The enrichment of amino groups on the nanofiber surface was confirmed by X-ray photoelectron spectroscopy (XPS). With the increase of CS-g-PCL in CS-g-PCL/PCL nanofiber, the content of amino groups on the nanofiber surface increased, which resulted in the increase of zeta-potential of nanofibers. Studies on cell-scaffold interaction were carried out by culturing mouse fibroblast cells (L929) on CS-g-PCL/PCL nanofibrous mats with various contents of CS-g-PCL by assessing the growth, proliferation and morphologies of cells. The results of MTS assay and SEM observation showed that CS-g-PCL/PCL (2/8) mats with a moderate surface zeta-potential (ζ=3mV) were the best in promoting the cell attachment and proliferation. Toluidine blue staining further confirmed that L929 cells grew well and exhibited a normal morphology on the CS-g-PCL/PCL (2/8) mats. These results suggested the potential utilization of CS-g-PCL/PCL (2/8) nanofibrous mats for skin tissue engineering. Copyright © 2010 Elsevier B.V. All rights reserved.

  6. Nanostructured biomaterials from electrospun demineralized bone matrix: a survey of processing and crosslinking strategies.

    PubMed

    Leszczak, Victoria; Place, Laura W; Franz, Natalee; Popat, Ketul C; Kipper, Matt J

    2014-06-25

    In the design of scaffolds for tissue engineering biochemical function and nanoscale features are of particular interest. Natural polymers provide a wealth of biochemical function, but do not have the processability of synthetic polymers, limiting their ability to mimic the hierarchy of structures in the natural extracellular matrix. Thus, they are often combined with synthetic carrier polymers to enable processing. Demineralized bone matrix (DBM), a natural polymer, is allograft bone with inorganic material removed. DBM contains the protein components of bone, which includes adhesion ligands and osteoinductive signals, such as important growth factors. Herein we describe a novel method for tuning the nanostructure of DBM through electrospinning without the use of a carrier polymer. This work surveys solvents and solvent blends for electrospinning DBM. Blends of hexafluoroisopropanol and trifluoroacetic acid are studied in detail. The effects of DBM concentration and dissolution time on solution viscosity are also reported and correlated to observed differences in electrospun fiber morphology. We also present a survey of techniques to stabilize the resultant fibers with respect to aqueous environments. Glutaraldehyde vapor treatment is successful at maintaining both macroscopic and microscopic structure of the electrospun DBM fibers. Finally, we report results from tensile testing of stabilized DBM nanofiber mats, and preliminary evaluation of their cytocompatibility. The DBM nanofiber mats exhibit good cytocompatibility toward human dermal fibroblasts (HDF) in a 4-day culture; neither the electrospun solvents nor the cross-linking results in any measurable residual cytotoxicity toward HDF.

  7. Ceria-based electrospun fibers for renewable fuel production via two-step thermal redox cycles for carbon dioxide splitting.

    PubMed

    Gibbons, William T; Venstrom, Luke J; De Smith, Robert M; Davidson, Jane H; Jackson, Gregory S

    2014-07-21

    Zirconium-doped ceria (Ce(1-x)Zr(x)O2) was synthesized through a controlled electrospinning process as a promising approach to cost-effective, sinter-resistant material structures for high-temperature, solar-driven thermochemical redox cycles. To approximate a two-step redox cycle for solar fuel production, fibrous Ce(1-x)Zr(x)O2 with relatively low levels of Zr-doping (0 < x < 0.1) were cycled in an infrared-imaging furnace with high-temperature (up to 1500 °C) partial reduction and lower-temperature (∼800 °C) reoxidation via CO2 splitting to produce CO. Increases in Zr content improve reducibility and sintering resistance, and, for x≤ 0.05, do not significantly slow reoxidation kinetics for CO production. Cycle stability of the fibrous Ce(1-x)Zr(x)O2 (with x = 0.025) was assessed for a range of conditions by measuring rates of O2 release during reduction and CO production during reoxidation and by assessing post-cycling fiber crystallite sizes and surface areas. Sintering increases with reduction temperature but occurs primarily along the fiber axes. Even after 108 redox cycles with reduction at 1400 °C and oxidation with CO2 at 800 °C, the fibers maintain their structure with surface areas of ∼0.3 m(2) g(-1), higher than those observed in the literature for other ceria-based structures operating at similarly high temperature conditions. Total CO production and peak production rate stabilize above 3.0 mL g(-1) and 13.0 mL min(-1) g(-1), respectively. The results show the potential for electrospun oxides as sinter-resistant material structures with adequate surface area to support rapid CO2 splitting in solar thermochemical redox cycles.

  8. 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.

  9. Size control of electrospun hydroxyapatite nanofibers by sol-gel system.

    PubMed

    Zhou, Yuanyuan; Li, Yike; Liu, Qian; Li, Zhongjun

    2013-10-01

    This work reported the production of hydroxyapatite nanofibers by combining electrospinning and a sol-gel system in details. The fibers were electrospun from a mixture of the sol formed with Ca(NO3)2 x 4H2O/P2O5 in ethanol/ethylene glycol solution mixtures and the polyvinylpyrrolidone polymer, followed by a thermal treatment. The nanofibers were analyzed for their morphology (Scanning Electron Microscopy, SEM), chemical composition (Fourier Transform Infrared Spectroscopy, FTIR) and structure (X-ray diffraction, XRD) as well as thermal properties (Differential scanning calorimetric, DSC and thermogravimetric, TG). The results indicated that the sol was distributed uniformly in the PVP fibers. After calcinations at 600 degrees C for 3 h, the pure HAP phase could be obtained, and the smooth as-electrospun fibers shrunk and the fiber diameter decreased because of the removal of the polymer. Based on the systematic parametric study, it was possible to control the diameter ranging from 400 to 900 nm and morphology of the electrospun polymer fibers. Moreover, thses HAP nanofibers were flexible as cotton and the fibers mat would not rupture even folding it on a paper. So the good flexibility and high mechanical properties might favor their application in the future.

  10. Electrospun MgO-loaded carbon nanofibers: Enhanced field electron emission from the fibers in vacuum

    NASA Astrophysics Data System (ADS)

    Aykut, Yakup

    2013-02-01

    MgO-loaded electrospun carbon nanofibers (MgO/CNFs) were prepared by electrospinning a magnesium acetate containing polyacrylonitrile composite followed by stabilization under an air atmosphere at 280 °C and carbonization under a nitrogen atmosphere at 800 °C. In addition to investigating the morphological and material features of the nanofibers, the field emission (FE) characteristics of the carbonized NFs (CNFs), performed in an ultra-high vacuum chamber utilizing scanning electron microscopy (SEM), were determined. The results of the investigation show that the MgO/CNFs (195.5% enhancement) display enhanced field electron emission as compared to that of pure CNFs as a result of the existence of a MgO phase. Consequently, it appears that the graphitic structures of CNFs can be tuned, a finding that has significance in studies aimed at developing new field electron emission devices.

  11. 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.

  12. Electrospun porous conductive polymer membranes

    NASA Astrophysics Data System (ADS)

    Wang, Jingwen; Naguib, Hani E.; Bazylak, Aimy

    2012-04-01

    In this work, two methodologies were used in fabricating conductive electrospun polymer fibers with nano features. We first investigated the addition of multiwall carbon nanotubes (MWCNT) as conductive fillers at concentrations ranging from 1 to 10% into a polystyrene (PS) matrix. Electrospinning conditions were tailored to produce fibers with minimal beads. Next, we investigated the effects of coating electrospun fibers with nano structured conductive polymer. Oxidant (FeCl3) fibers were electrospun in PS and then exposed to a pyrrole (Py) monomer in a vacuum chamber. As a result, polypyrrole (PPy) was coated on the fibers creating conductive pathways. In both methods, the electrospun conductive fibers were characterized in terms of their morphologies, thermal stability and electrical conductivity. Strong correlations were found among PPy coating nanostructures, oxidant concentration and polymerization time. Electrospun fibrous membranes with conductive polymer coating exhibit much higher electrical conductivities compare to fibers with conductive fillers. Highest conductivity achieved was 9.5E-4 S/cm with 40% FeCl3/PS fibers polymerized with Py for 140 min.

  13. Electrospun polycaprolactone scaffolds with tailored porosity using two approaches for enhanced cellular infiltration.

    PubMed

    Zander, Nicole E; Orlicki, Joshua A; Rawlett, Adam M; Beebe, Thomas P

    2013-01-01

    The impact of mat porosity of polycaprolactone (PCL) electrospun fibers on the infiltration of neuron-like PC12 cells was evaluated using two different approaches. In the first method, bi-component aligned fiber mats were fabricated via the co-electrospinning of PCL with polyethylene oxide (PEO). Variation of the PEO flow rate, followed by selective removal of PEO from the PCL/PEO mesh, allowed for control of the porosity of the resulting scaffold. In the second method, aligned fiber mats were fabricated from various concentrations of PCL solutions to generate fibers with diameters between 0.13 ± 0.06 and 9.10 ± 4.1 μm. Of the approaches examined, the variation of PCL fiber diameter was found to be the better method for increasing the infiltration of PC12 cells, with the optimal infiltration into the ca. 1.5-mm-thick meshes observed for the mats with the largest fiber diameters, and hence largest pore sizes.

  14. 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. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  15. 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

  16. 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.

  17. Polyelectrolyte-Functionalized Nanofiber Mats Control the Collection and Inactivation of Escherichia coli

    PubMed Central

    Rieger, Katrina A.; Porter, Michael; Schiffman, Jessica D.

    2016-01-01

    Quantifying the effect that nanofiber mat chemistry and hydrophilicity have on microorganism collection and inactivation is critical in biomedical applications. In this study, the collection and inactivation of Escherichia coli K12 was examined using cellulose nanofiber mats that were surface-functionalized using three polyelectrolytes: poly (acrylic acid) (PAA), chitosan (CS), and polydiallyldimethylammonium chloride (pDADMAC). The polyelectrolyte functionalized nanofiber mats retained the cylindrical morphology and average fiber diameter (~0.84 µm) of the underlying cellulose nanofibers. X-ray photoelectron spectroscopy (XPS) and contact angle measurements confirmed the presence of polycations or polyanions on the surface of the nanofiber mats. Both the control cellulose and pDADMAC-functionalized nanofiber mats exhibited a high collection of E. coli K12, which suggests that mat hydrophilicity may play a larger role than surface charge on cell collection. While the minimum concentration of polycations needed to inhibit E. coli K12 was 800 µg/mL for both CS and pDADMAC, once immobilized, pDADMAC-functionalized nanofiber mats exhibited a higher inactivation of E. coli K12, (~97%). Here, we demonstrate that the collection and inactivation of microorganisms by electrospun cellulose nanofiber mats can be tailored through a facile polyelectrolyte functionalization process. PMID:28773422

  18. Bioinspired crystallization of CaCO3 coatings on electrospun cellulose acetate fiber scaffolds and corresponding CaCO3 microtube networks.

    PubMed

    Liu, Lei; He, Dian; Wang, Guang-Sheng; Yu, Shu-Hong

    2011-06-07

    This article describes the mineralization behavior of CaCO(3) crystals on electrospun cellulose acetate (CA) fibers by using poly(acrylic acid) (PAA) as a crystal growth modifier and further templating synthesis of CaCO(3) microtubes. Calcite film coatings composed of nanoneedles can form on the surfaces of CA fibers while maintaining the fibrous and macroporous structures if the concentration of PAA is in a suitable range. In the presence of a suitable concentration of PAA, the acidic PAA molecules will first adsorb onto the surface of CA fibers by the interaction between the OH moieties of CA and the carboxylic groups of PAA, and then the redundant carboxylic groups of PAA can ionically bind Ca(2+) ions on the surfaces of CA fibers, resulting in the local supersaturation of Ca(2+) ions on and near the fiber surface, which can induce the nucleation of CaCO(3) on the CA fibers instead of in bulk solution. Calcite microtube networks on the macroscale can be prepared by the removal of CA fibers after the CA@CaCO(3) composite is treated with acetone. When the CA fiber scaffold is immersed in CaCl(2) solution with an extended incubation time, the first deposited calcite coatings can act as secondary substrate, leading to the formation of smaller calcite mesocrystal fibers. The present work proves that inorganic crystal growth can occur even at an organic interface without the need for commensurability between the lattices of the organic and inorganic counterparts.

  19. Highly oriented electrospun polycaprolactone micro/nanofibers prepared by a field-controllable electrode and rotating collector

    NASA Astrophysics Data System (ADS)

    Lee, Hyeongjin; Yoon, Hyeon; Kim, Geunhyung

    2009-11-01

    Highly aligned electrospun nanofibers were fabricated using a field-controllable electrospinning process. The technique involved a cylindrical electrode connected to a spinning nozzle to stabilize the initial jet, and a field-controllable electrode generating an alternating current (AC) electric field fixed with a rotating collector. Aligned polycaprolactone (PCL) micro/nanofibers were prepared successfully using this process. Due to two electrostatic forces, the Coulombic force and the field-induced torque due to dipole-dipole interaction, the PCL micro/nanofibers were highly stretched in the direction of the electric field; the alignment depended on the applied frequency of the electrode. Wide-angle X-ray diffraction measurement was used to observe the crystallinity and molecular orientation of the electrospun fiber mats. As using the field-controllable rotating collector, the molecular orientation of PCL was improved relative to that of the normal electrospinning process. The oriented electrospun PCL fibers exhibited an increased storage modulus compared to conventionally fabricated electrospun fibers. In addition, the average fiber diameter was reduced and the distribution was narrower compared to those fabricated by the conventional electrospinning process.

  20. Antitumor activity of electrospun polylactide nanofibers loaded with 5-fluorouracil and oxaliplatin against colorectal cancer.

    PubMed

    Zhang, Jiayu; Wang, Xue; Liu, Tongjun; Liu, Shi; Jing, Xiabin

    2016-01-01

    The purpose of this study was to evaluate both in vitro and in vivo anticancer activities against colorectal cancer (CRC) of electrospun polylactide (PLA) nanofibers loaded with 5-fluorouracil (5-Flu) and oxaliplatin. For in vitro evaluation, human CRC HCT8 cells were directly exposed to the drug-loaded fiber mats, followed with MTT and flow cytometry (FCM) assay. For in vivo evaluation, the drug-loaded fiber mats were locally implanted into mouse colorectal CT26 tumor-bearing mice, followed with histological analysis and detection of survival rate. The results showed that the drug-loaded fiber mats was similar to that of the combination of free 5-Flu and oxaliplatin in vitro cytotoxicity but was much superior to intravenous injection of free drug in vivo anticancer activities, presenting with suppressed tumor growth rate and prolonged survival time of mice. In conclusion, anticancer activities of 5-Flu and oxaliplatin against CRC can be significantly improved by using PLA electrospun nanofibers as local drug delivery system.

  1. Mechanical and electrical properties of electrospun PVDF/MWCNT ultrafine fibers using rotating collector

    PubMed Central

    2014-01-01

    Poly(vinylidene fluoride) (PVDF) ultrafine fibers with different proportions of multi-walled carbon nanotube (MWCNT) embedded have been fabricated using a modified electrospinning device with a rotating collector. With the increasing of MWCNT content, the β phase was noticeable enhanced, and the fibers became more elastic, which was manifested by Young's modulus decreased drastically. Furthermore, with adding the amounts of MWCNTs, the density of carbon nanotube (CNT)-CNT junctions among the fibers increased accordingly. When the MWCNT content was of 1.2 wt.%, a stable three-dimensional conducting network was formed. After this percolation threshold, the density of CNT-CNT junctions among the fibers tended to be a constant quantity, leading to a stabilized conductivity consequently. It is hoped that our results can be helpful for the fabrication of flexible devices, piezoelectric devices, force transducer, and so on. PACS 81.05.Qk; 81.16.-c PMID:25288915

  2. Mechanical and electrical properties of electrospun PVDF/MWCNT ultrafine fibers using rotating collector.

    PubMed

    Wang, Shu-Hua; Wan, Yong; Sun, Bin; Liu, Ling-Zhi; Xu, Weijiang

    2014-01-01

    Poly(vinylidene fluoride) (PVDF) ultrafine fibers with different proportions of multi-walled carbon nanotube (MWCNT) embedded have been fabricated using a modified electrospinning device with a rotating collector. With the increasing of MWCNT content, the β phase was noticeable enhanced, and the fibers became more elastic, which was manifested by Young's modulus decreased drastically. Furthermore, with adding the amounts of MWCNTs, the density of carbon nanotube (CNT)-CNT junctions among the fibers increased accordingly. When the MWCNT content was of 1.2 wt.%, a stable three-dimensional conducting network was formed. After this percolation threshold, the density of CNT-CNT junctions among the fibers tended to be a constant quantity, leading to a stabilized conductivity consequently. It is hoped that our results can be helpful for the fabrication of flexible devices, piezoelectric devices, force transducer, and so on. 81.05.Qk; 81.16.-c.

  3. 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.

  4. 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}.

  5. Novel bioactive tetracycline-containing electrospun polymer fibers as a potential antibacterial dental implant coating.

    PubMed

    Shahi, R G; Albuquerque, M T P; Münchow, E A; Blanchard, S B; Gregory, R L; Bottino, M C

    2016-09-01

    The purpose of this investigation was to determine the ability of tetracycline-containing fibers to inhibit biofilm formation of peri-implantitis-associated pathogens [i.e., Porphyromonas gingivalis (Pg), Fusobacterium nucleatum (Fn), Prevotella intermedia (Pi), and Aggregatibacter actinomycetemcomitans (Aa)]. Tetracycline hydrochloride (TCH) was added to a poly(DL-lactide) [PLA], poly(ε-caprolactone) [PCL], and gelatin [GEL] polymer blend solution at distinct concentrations to obtain the following fibers: PLA:PCL/GEL (TCH-free, control), PLA:PCL/GEL + 5 % TCH, PLA:PCL/GEL + 10 % TCH, and PLA:PCL/GEL + 25 % TCH. The inhibitory effect of TCH-containing fibers on biofilm formation was assessed by colony-forming units (CFU/mL). Qualitative analysis of biofilm inhibition was done via scanning electron microscopy (SEM). Statistical significance was reported at p < 0.05. Complete inhibition of biofilm formation on the fibers was observed in groups containing TCH at 10 and 25 wt%. Fibers containing TCH at 5 wt% demonstrated complete inhibition of Aa biofilm. Even though a marked reduction in CFU/mL was observed with an increase in TCH concentration, Pi proved to be the most resilient microorganism. SEM images revealed the absence of or a notable decrease in bacterial biofilm on the TCH-containing nanofibers. Collectively, our data suggest that tetracycline-containing fibers hold great potential as an antibacterial dental implant coating.

  6. Functionalization of electrospun fibers of poly(epsilon-caprolactone) with star shaped NCO-poly(ethylene glycol)-stat-poly(propylene glycol) for neuronal cell guidance.

    PubMed

    Klinkhammer, Kristina; Bockelmann, Julia; Simitzis, Chariklia; Brook, Gary A; Grafahrend, Dirk; Groll, Jürgen; Möller, Martin; Mey, Jörg; Klee, Doris

    2010-09-01

    Microfibers produced with electrospinning have recently been used in tissue engineering. In the development of artificial implants for nerve regeneration they are of particular interest as guidance structures for cell migration and axonal growth. Using electrospinning we produced parallel-orientated biocompatible fibers in the submicron range consisting of poly(epsilon-caprolactone) (PCL) and star shaped NCO-poly(ethylene glycol)-stat-poly(propylene glycol) (sPEG). Addition of the bioactive peptide sequence glycine-arginine-glycine-aspartate-serine (GRGDS) or the extracellular matrix protein fibronectin to the electrospinning solution resulted in functionalized fibers. Surface characteristics and biological properties of functionalized and non-functionalised fibers were investigated. Polymer solutions and electrospinning process parameters were varied to obtain high quality orientated fibers. A polymer mixture containing high molecular weight PCL, PCL-diol, and sPEG permitted a chemical reaction between hydroxyl groups of the diol and isocyanante groups of the sPEG. Surface analysis demonstrated that sPEG at the fiber surface minimized protein adhesion. In vitro experiments using dorsal root ganglia explants showed that the cell repellent property of pure PCL/sPEG fibers was overcome by functionalization either with GRGDS peptide or fibronectin. In this way cell migration and axonal outgrowth along fibers were significantly increased. Thus, functionalized electrospun PCL/sPEG fibers, while preventing non-specific protein adsorption, are a suitable substrate for biological and medical applications.

  7. Nanostructured poly (lactic acid) electrospun fiber with high loadings of TiO2 nanoparticles: Insights into bactericidal activity and cell viability.

    PubMed

    Toniatto, T V; Rodrigues, B V M; Marsi, T C O; Ricci, R; Marciano, F R; Webster, T J; Lobo, A O

    2017-02-01

    Researchers have been looking for modifying surfaces of polymeric biomaterials approved by FDA to obtain nanofeatures and bactericidal properties. If modified, it would be very interesting because the antibiotic administration could be reduced and, therefore, the bacterial resistance. Here, we report the electrospinning of poly (lactic acid) (PLA) with high loadings of titanium dioxide nanoparticles (TiO2, 1-5wt%) and their bactericidal properties. TiO2 nanoparticles have been recognized for a long time for their antibacterial, low cost and self-cleaning properties. However, their ability to reduce bacteria functions when used in polymers has not been well studied to date. In this context, we aimed here to generate nanostructured PLA electrospun fiber-TiO2 nanoparticle composites for further evaluation of their bactericidal activity and cell viability. TEM and SEM micrographs revealed the successful electrospinning of PLA/TiO2 and the generation of polymer-TiO2 nanostructures. When increasing the TiO2 concentration, we observed a proportional increase in the nanoparticle density along the fiber and surface. The nanostructured PLA/TiO2 nanofibers showed no mammalian cell toxicity and, most importantly, possessed bactericidal activity with higher TiO2 loads. Such results suggest that the present PLA electrospun fiber-TiO2 nanoparticle composites should be further studied for a wide range of biomedical applications.

  8. Dynamics and morphology development in electrospun fibers driven by concentration sweeps

    NASA Astrophysics Data System (ADS)

    Dayal, Pratyush; Kyu, Thein

    2007-10-01

    The present article describes the modeling and simulation of the dynamics of the electrospinning process coupled with the spatio-temporal evolution of fiber morphology driven by concentration sweeps. The electrospinning process has been modeled based on an array of beads connected by Maxwell's elements in a cylindrical shell to describe the force balance between Coulombic and viscoelastic forces at the surface of the jet. The phase separation dynamics has been calculated in the framework of the Cahn-Hilliard time-evolution equation by incorporating Flory-Huggins free energy for liquid-liquid demixing in conjunction with solvent evaporation through the fiber surface. The simulations based on the coupling of these two processes have revealed in situ morphology development registering all structural forming processes such as polymer droplets, interconnected spinodal structure, and the porous structure along the spinline. The simulated porous fiber shows a striking resemblance to the experimental finding.

  9. Effect of vapor-phase glutaraldehyde crosslinking on electrospun starch fibers.

    PubMed

    Wang, Wenyu; Jin, Xin; Zhu, Yonghao; Zhu, Chengzhang; Yang, Jian; Wang, Hongjie; Lin, Tong

    2016-04-20

    In this work, we have proven that starch nanofibrous membranes with high tensile strength, water stability and non-cytotoxicity can be produced by electrospinning of starch solution and post-treatment with GTA in vapor phase. GTA vapor phase crosslinking plays a key role in forming water-stable nanofiber membrane and improving the mechanical properties. Comparing with non-crosslinked starch fibers, the crosslinked fibers are increased by nearly 10 times in tensile strength. The crosslinked starch fibrous membranes are non-cytotoxic. They may find applications in the fields of tissue engineering, pharmaceutical therapy and medical. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. 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

  11. An IR thermal imaging method to investigate spreading process of ethanol solution droplets on carbon fiber mats

    NASA Astrophysics Data System (ADS)

    Zhang, Bin; Lu, Longsheng; Teh, Kwok Siong; Wang, Hongfei; Wan, Zhenping; Tang, Yong

    2016-12-01

    Porous media are a class of basic engineering material, and the applications of a porous medium are significantly influenced by its surface and bulk wettabilities. Conventionally, the surface wettability and dynamics of a liquid droplet on a stationary material surface can be observed by performing a dyed droplet spreading test captured with a high-speed camera. Such a method, however, is not effective in the quantification of droplet dynamics within a porous medium. In this work, we propose an infrared (IR) thermal imaging method to investigate the spreading of colorless droplet beneath the surface of, and within, the porous network of the porous medium. The spreading rim of a colorless droplet is accurately detected by the locations of extreme points in its temperature gradient curve, as deduced from temperature distribution data collected by an IR camera imaging from the top. Compared with the images captured simultaneously by a high-speed camera from the side, the droplet spreading rim is revealed to be an inner precursor rim located inside the porous media. To evaluate this method, carbon fiber (CF) mats with different porosities are used as the porous media. The spreading velocities of droplets in CF mats are measured successfully and coincide exactly with conclusions obtained by the background subtraction method. This finding validates the effectiveness of IR thermal imaging method in a droplet spreading test. This work demonstrates that IR imaging holds great promise in the visualization of the inner precursor rim of droplets in porous media.

  12. Enhanced proliferation and osteogenic differentiation of mesenchymal stem cells on graphene oxide-incorporated electrospun poly(lactic-co-glycolic acid) nanofibrous mats.

    PubMed

    Luo, Yu; Shen, He; Fang, Yongxiang; Cao, Yuhua; Huang, Jie; Zhang, Mengxin; Dai, Jianwu; Shi, Xiangyang; Zhang, Zhijun

    2015-03-25

    Currently, combining biomaterial scaffolds with living stem cells for tissue regeneration is a main approach for tissue engineering. Mesenchymal stem cells (MSCs) are promising candidates for musculoskeletal tissue repair through differentiating into specific tissues, such as bone, muscle, and cartilage. Thus, successfully directing the fate of MSCs through factors and inducers would improve regeneration efficiency. Here, we report the fabrication of graphene oxide (GO)-doped poly(lactic-co-glycolic acid) (PLGA) nanofiber scaffolds via electrospinning technique for the enhancement of osteogenic differentiation of MSCs. GO-PLGA nanofibrous mats with three-dimensional porous structure and smooth surface can be readily produced via an electrospinning technique. GO plays two roles in the nanofibrous mats: first, it enhances the hydrophilic performance, and protein- and inducer-adsorption ability of the nanofibers. Second, the incorporated GO accelerates the human MSCs (hMSCs) adhesion and proliferation versus pure PLGA nanofiber and induces the osteogenic differentiation. The incorporating GO scaffold materials may find applications in tissue engineering and other fields.

  13. Larger-scale fabrication of N-doped graphene-fiber mats used in high-performance energy storage

    NASA Astrophysics Data System (ADS)

    Chang, Yunzhen; Han, Gaoyi; Fu, Dongying; Liu, Feifei; Li, Miaoyu; Li, Yanping

    2014-04-01

    The N-doped graphene fibers mats (NG-FMs) have been fabricated through spinning GO into ethanol solution of hydroxylamine and following thermal treatment. The NG-FMs are flexible and possess pores with the large interior and small entrance. The results of characterization indicate that N has doped into the graphene sheets during the preparation of the fibers, and that the interplanar distance of the graphene sheets in the fibers has almost no change with the increase of the treating temperature. The capacitive properties of the NG-FMs have been investigated by electrochemical method using two-electrode symmetric capacitor test. The results show that the specific capacitance of NG-FMs can reach 188 F g-1 at scan rate of 5 mV s-1 and the capacitors assembled by them possess the high-rate capability (the impedance phase angle can reach -45° at 16.5 Hz) and good cycling stability. The energy density and power density of the capacitor can reach to 2.24 Wh kg-1 and 48.7 kW kg-1 at discharged current density of 300 A g-1 (excluding iR drop).

  14. Effect of fiber diameter on the spreading, proliferation and differentiation of chondrocytes on electrospun chitosan matrices.

    PubMed

    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 (α(5), αv, β(1)) 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.

  15. Electrospun zein fibers using glutaraldehyde as the cross-linking reagent

    USDA-ARS?s Scientific Manuscript database

    Glutaraldehyde was used as a cross-linking reagent for zein (corn protein) to provide fibers with improved physical properties and solvent resistance. Glutaraldehyde was used at levels between 2 - 8%. The cross-linking reaction was carried out in acetic acid for twenty hours at room temperature. ...

  16. 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. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Performance of electrospun poly(ε-caprolactone) fiber meshes used with mineral trioxide aggregates in a pulp capping procedure.

    PubMed

    Lee, WooCheol; Oh, Joung-Hwan; Park, Joo-Cheol; Shin, Hong-In; Baek, Jeong-Hwa; Ryoo, Hyun-Mo; Woo, Kyung Mi

    2012-08-01

    Living dental pulp tissue exposed to the oral environment should be protected with an appropriate pulp capping material to support the dentinogenesis potential of the pulp cells. Mineral trioxide aggregate (MTA) is the material of choice for the treatment of pulp. However, due to cytotoxicity during the initial setting phase of MTA, a new material is required that can act as a barrier to direct contact but facilitate the favorable effect of MTA. This study examined the feasibility of using electrospun poly(ε-caprolactone) fiber (PCL-F) meshes in the MTA-based pulp capping procedures. An experimental pulp capping was performed on the premolars of beagle dogs, and the efficacy of the PCL-F meshes was evaluated after 8 weeks. PCL-F/MTA formed a dentin bridge that was approximately fourfold thicker than that formed by the MTA. Columnar polarized odontoblast-like cells with long processes and tubular dentin-like matrices were observed beneath the dentin bridge in the PCL-F/MTA. The cells were also intensely immunostained for dentin sialoprotein. In cell cultures, PCL-F/MTA reduced cell death to ~8% of that in the MTA group. The proliferation of the cells cultured on PCL-F/MTA was much greater than that of cells cultured on MTA. Furthermore, PCL-F/MTA promoted the differentiation of MDPC23 cells to odontoblast-like cells and biomineralization, as confirmed by the expression of alkaline phosphatase and dentin sialophosphoprotein, and by the deposition of calcium. Based on these histologic findings and the cell responses observed in this study, PCL-F may be used efficiently in the MTA-based dental pulp therapy.

  18. 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 s