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Sample records for nanofibrous substrates support

  1. Preparation of thin film nanofibrous composite NF membrane based on EDC/NHS modified PAN-AA nanofibrous substrate

    Science.gov (United States)

    Yang, Y.; Wang, X.; Hsiao, B. S.

    2016-07-01

    A novel kind of thin-film nanofibrous composite (TFNC) nanofiltration (NF) membranes consisting of a polyamide (PA) barrier layer were successfully fabricated by interfacial polymerization (IFP) based on electrospun double-layer nanofibrous substrates, which have an ultrathin poly (acrylonitrile-co-acrylic acid) (PAN-AA) nanofibrous layer as top layer and a thicker polyacrylonitrile (PAN) nanofiber layer as bottom porous support layer. Immersing PAN/PAN-AA nanofibrous substrates into 1-ethyl-(3-3-dimethylaminopropyl) carbodiimide hydrochloride/N-hydroxysuccinimide (EDC/NHS) aqueous solution and piperazine (PIP) aqueous solution (0.20 wt%) sequentially for a period of time, the carboxyl groups on PAN-AA nanofibers were activated by carbodiimide and then reacted with the amide groups. The as prepared composite membrane has an integrated structure with high rejection rate (98.0%); high permeate flux (40.4 L/m2h) for MgSO4 aqueous solution (2 g/L).

  2. High flux filtration medium based on nanofibrous substrate with hydrophilic nanocomposite coating.

    Science.gov (United States)

    Wang, Xuefen; Chen, Xuming; Yoon, Kyunghwan; Fang, Dufei; Hsiao, Benjamin S; Chu, Benjamin

    2005-10-01

    A novel high flux filtration medium, consisting of a three-tier composite structure, i.e., a nonporous hydrophilic nanocomposite coating top layer, an electrospun nanofibrous substrate midlayer, and a conventional nonwoven microfibrous support, was demonstrated for oil/water emulsion separations for the first time. The nanofibrous substrate was prepared by electrospinning of poly(vinyl alcohol) (PVA) followed by chemical cross-linking with glutaraldehyde (GA) in acetone. The resulting cross-linked PVA substrates showed excellent water resistance and good mechanical properties. The top coating was based on a nanocomposite layer containing hydrophilic polyether-b-polyamide copolymer or a cross-linked PVA hydrogel incorporated with surface-oxidized multiwalled carbon nanotubes (MWNTs). Scanning electron microscopy (SEM) examinations indicated that the nanocomposite layer was nonporous within the instrumental resolution and MWNTs were well dispersed in the polymer matrix. Oil/ water emulsion tests showed that this unique type of filtration media exhibited a high flux rate (up to 330 L/m2-h at the feed pressure of 100 psi) and an excellent total organic solute rejection rate (99.8%) without appreciable fouling. The increase in the concentration of surface-oxidized MWNT in the coating layer generally improves the flux rate, which can be attributed to the generation of more effective hydrophilic nanochannels for water passage in the composite membranes.

  3. Simple fabrication of Ag nanoparticle-impregnated electrospun nanofibres as SERS substrates

    Indian Academy of Sciences (India)

    Altangerel Amarjargal; Leonard D Tijing; Cheol Sang Kim

    2015-02-01

    A facile method for the fabrication of electrospun polyurethane (PU) nanofibres impregnated with Ag nanoparticles (NPs) as an efficient and free-standing surface-enhanced Raman scattering (SERS) substrates is reported here. Electrospinning was used to produce polymeric nanofibrous matrix, while a liquid polyol(ethylene glycol) solvent under low temperature was used not only to reduce Ag+ to Ag0, but also was employed as the in situ growth medium for well-dispersed Ag NPs on the surface of fibre nets. Large enhancement in Raman signals of 4-mercaptobenzoic acid analytes could be realized in the present Ag/PU nanofibres due to the presence of SERS ‘hotspots’ by means of appropriate interparticle gap.

  4. Electrohydrodynamic Direct-Write Orderly Micro/Nanofibrous Structure on Flexible Insulating Substrate

    Directory of Open Access Journals (Sweden)

    Jiang-Yi Zheng

    2014-01-01

    Full Text Available AC pulse-modulated electrohydrodynamic direct-writing (EDW was utilized to direct-write orderly micro/nanofibrous structure on the flexible insulating polyethylene terephthalate (PET substrate. During the EDW process, AC electrical field induced charges to reciprocate along the jet and decreased the charge repulsive force that applied on charged jet. Thanks to the smaller charge repulsive force, stable straight jet can be built up to direct-write orderly micro/nanofibrous structures on the insulating substrate. The minimum motion velocity required to direct-write straight line fibrous structure on insulating PET substrate was 700 mm/s. Moreover, the influences of AC voltage amplitude, frequency, and duty cycle ratio on the line width of fibrous structures were investigated. This work proposes a novel solution to overcome the inherent charge repulsion emerging on the insulating substrate, and promotes the application of EDW technology on the flexible electronics.

  5. Xylan polysaccharides fabricated into nanofibrous substrate for myocardial infarction

    Energy Technology Data Exchange (ETDEWEB)

    Venugopal, J., E-mail: nnijrv@nus.edu.sg; Rajeswari, R.; Shayanti, M.; Sridhar, R.; Sundarrajan, S.; Balamurugan, R.; Ramakrishna, S.

    2013-04-01

    Myocardial infarction, a main cause of heart failure, leads to loss of cardiac tissue impairment of left ventricular function. Repair of diseased myocardium with in vitro engineered cardiac muscle patch/injectable biopolymers with cells may become a viable option for myocardial infarction. We attempted to solve these problems by in vitro study by selecting a plant based polysaccharides beech wood Xylan for the normal functioning of infarcted myocardium. The present study fabricated Xylan based nanofibrous scaffolds cross-linked with glutaraldehyde (Glu) vapors for 24 h, 48 h and 1% Glu blended fibers for the culture of neonatal rat cardiac cells for myocardial infarction. These nanofibers were characterized by SEM, FT-IR, tensile testing and cell culture studies for the normal expression of cardiac proteins. The observed results showed that the Xylan/polyvinyl alcohol (PVA) 24 h Glu vapor cross-linked nanofibers (427 nm) having mechanical strength of 2.43 MPa and Young modulus of 3.74 MPa are suitable for the culture of cardiac cells. Cardiac cells proliferation increased only by 11% in Xylan/PVA 24 h Glu cross-linked nanofibers compared to control tissue culture plate (TCP). The normal cardiac cell morphology was observed in 24 h cross-linked Xylan/PVA nanofibers but 48 h cross-linked fibers cell morphology was changed to flattened and elongated on the fibrous surfaces. Confocal analysis for cardiac expression proteins actinin, connexin 43 was observed normally in 24 h Glu cross-linked nanofibers compared to all other nanofibrous scaffolds. The fabricated Xylan/PVA nanofibrous scaffold may have good potential for the normal functioning of infarcted myocardium. - Highlights: ► Fabrication of polysaccharides Xylan/PVA nanofibers for cardiac tissue engineering ► Nanofibers characterized by SEM, FT-IR, tensile testing and cell culture studies ► Isolation of cardiac cells and cultured on Xylan/PVA nanofibrous scaffolds ► Cultured cells on 24 h Glu cross

  6. Non-covalently crosslinked chitosan nanofibrous mats prepared by electrospinning as substrates for soft tissue regeneration.

    Science.gov (United States)

    Tonda-Turo, Chiara; Ruini, Francesca; Ramella, Martina; Boccafoschi, Francesca; Gentile, Piergiorgio; Gioffredi, Emilia; Falvo D'Urso Labate, Giuseppe; Ciardelli, Gianluca

    2017-04-15

    Chitosan (CS) membranes obtained by electrospinning are potentially ideal substrates for soft tissue engineering as they combine the excellent biological properties of CS with the extracellular matrix (ECM)-like structure of nanofibrous mats. However, the high amount of acid solvents required to spun CS solutions interferes with the biocompatibility of CS fibres. To overcome this limitation, novel CS based solutions were investigated in this work. Low amount of acidic acid (0.5M) was used and dibasic sodium phosphate (DSP) was introduced as ionic crosslinker to improve nanofibres water stability and to neutralize the acidic pH of electrospun membranes after fibres soaking in biological fluids. Randomly oriented and aligned nanofibres (128±19nm and 140±41nm, respectively) were obtained through electrospinning process (voltage of 30kV, 30μL/min flow rate and temperature of 39°C) showing mechanical properties similar to those of soft tissues (Young Modulus lower than 40MPa in dry condition) and water stability until 7 days. C2C12 myoblast cell line was cultured on CS fibres showing that the aligned architecture of substrate induces cell orientation that can enhance skeletal muscle regeneration.

  7. Large Scale Synthesis of Carbon Nanofibres on Sodium Chloride Support

    Directory of Open Access Journals (Sweden)

    Ravindra Rajarao

    2012-06-01

    Full Text Available Large scale synthesis of carbon nanofibres (CNFs on a sodium chloride support has been achieved. CNFs have been synthesized using metal oxalate (Ni, Co and Fe as catalyst precursors at 680 C by chemical vapour deposition method. Upon pyrolysis, this catalyst precursors yield catalyst nanoparticles directly. The sodium chloride was used as a catalyst support, it was chosen because of its non‐toxic and water soluble nature. Problems, such as the detrimental effect of CNFs, the detrimental effects on the environment and even cost, have been avoided by using a water soluble support. The structure of products was characterized by scanning electron microscopy, transmission electron microscopy and Raman spectroscopy. The purity of the grown products and purified products were determined by the thermal analysis and X‐ray diffraction method. Here we report the 7600, 7000 and 6500 wt% yield of CNFs synthesized over nickel, cobalt and iron oxalate. The long, curved and worm shaped CNFs were obtained on Ni, Co and Fe catalysts respectively. The lengthy process of calcination and reduction for the preparation of catalysts is avoided in this method. This synthesis route is simple and economical, hence, it can be used for CNF synthesis in industries.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  10. Porous nanofibrous poly(L-lactic acid) scaffolds supporting cardiovascular progenitor cells for cardiac tissue engineering.

    Science.gov (United States)

    Liu, Qihai; Tian, Shuo; Zhao, Chao; Chen, Xin; Lei, Ienglam; Wang, Zhong; Ma, Peter X

    2015-10-01

    Myocardial infarction (MI) is the irreversible necrosis of heart with approximately 1.5 million cases every year in the United States. Tissue engineering offers a promising strategy for cardiac repair after MI. However, the optimal cell source for heart tissue regeneration and the ideal scaffolds to support cell survival, differentiation, and integration, remain to be developed. To address these issues, we developed the technology to induce cardiovascular progenitor cells (CPCs) derived from mouse embryonic stem cells (ESCs) towards desired cardiomyocytes as well as smooth muscle cells and endothelial cells. We fabricated extracellular matrix (ECM)-mimicking nanofibrous poly(l-lactic acid) (PLLA) scaffolds with porous structure of high interconnection for cardiac tissue formation. The CPCs were seeded into the scaffolds to engineer cardiac constructs in vitro. Fluorescence staining and RT-PCR assay showed that the scaffolds facilitated cell attachment, extension, and differentiation. Subcutaneous implantation of the cell/scaffold constructs in a nude mouse model showed that the scaffolds favorably supported survival of the grafted cells and their commitment to the three desired lineages in vivo. Thus, our study suggested that the porous nanofibrous PLLA scaffolds support cardiac tissue formation from CPCs. The integration of CPCs with the nanofibrous PLLA scaffolds represents a promising tissue engineering strategy for cardiac repair. Myocardial infarction is the irreversible necrosis of heart with approximately 1.5 million cases every year in the United States. Tissue engineering offers a promising strategy for cardiac repair after MI. However, the optimal cell source for heart tissue regeneration and the ideal scaffolds to support cell survival, differentiation, and integration, remain to be developed. To address these issues, we developed porous nanofibrous PLLA scaffolds that mimic natural extracellular matrix to support cardiac tissue formation from CPCs. The

  11. Biomimetic hybrid nanofibrous substrates for mesenchymal stem cells differentiation into osteogenic cells

    Energy Technology Data Exchange (ETDEWEB)

    Gandhimathi, Chinnasamy [Cellular and Molecular Epigenetics Lab, Lee Kong Chian School of Medicine, Nanyang Technological University (Singapore); Venugopal, Jayarama Reddy [Center for Nanofibers and Nanotechnology, Nanoscience and Nanotechnology Initiative, National University of Singapore (Singapore); Tham, Allister Yingwei [Cellular and Molecular Epigenetics Lab, Lee Kong Chian School of Medicine, Nanyang Technological University (Singapore); Ramakrishna, Seeram [Center for Nanofibers and Nanotechnology, Nanoscience and Nanotechnology Initiative, National University of Singapore (Singapore); Kumar, Srinivasan Dinesh, E-mail: dineshkumar@ntu.edu.sg [Cellular and Molecular Epigenetics Lab, Lee Kong Chian School of Medicine, Nanyang Technological University (Singapore)

    2015-04-01

    Mimicking native extracellular matrix with electrospun porous bio-composite nanofibrous scaffolds has huge potential in bone tissue regeneration. The aim of this study is to fabricate porous poly(L-lactic acid)-co-poly-(ε-caprolactone)/silk fibroin/ascorbic acid/tetracycline hydrochloride (PLACL/SF/AA/TC) and nanohydroxyapatite (n-HA) was deposited by calcium-phosphate dipping method for bone tissue engineering (BTE). Fabricated nanofibrous scaffolds were characterized for fiber morphology, hydrophilicity, porosity, mechanical test and chemical properties by FT-IR and EDX analysis. The results showed that the fiber diameter and pore size of scaffolds observed around 228 ± 62–320 ± 22 nm and 1.5–6.9 μm respectively. Resulting nanofibrous scaffolds are highly porous (87–94%) with ultimate tensile strength observed in the range of 1.51–4.86 MPa and also showed better hydrophilic properties after addition of AA, TC and n-HA. Human mesenchymal stem cells (MSCs) cultured on these bio-composite nanofibrous scaffolds and stimulated to osteogenic differentiation in the presence of AA/TC/n-HA for BTE. The cell proliferation and biomaterial interactions were studied using MTS assay, SEM and CMFDA dye exclusion methods. Osteogenic differentiation of MSCs was proven by using alkaline phosphatase activity, mineralization and double immunofluorescence staining of both CD90 and osteocalcin. The observed results suggested that the fabricated PLACL/SF/AA/TC/n-HA biocomposite hybrid nanofibrous scaffolds have good potential for the differentiation of MSCs into osteogenesis for bone tissue engineering. - Highlights: • We fabricated and characterized hybrid porous nanofibrous scaffolds. • PLACL/SF/AA/TC/n-HA scaffolds promote cell differentiation and mineralization. • Porous nanofibrous scaffolds initiate MSC differentiation into osteogenic cells. • Biomimetic nanofibrous scaffolds have good potential for bone tissue engineering.

  12. Graphitised Carbon Nanofibres as Catalyst Support for PEMFC

    DEFF Research Database (Denmark)

    Yli-Rantala, E.; Pasanen, A.; Kauranen, P.

    2011-01-01

    for the anchorage of Pt catalyst nanoparticles. Modification of the fibre surface is therefore needed. In this study Pt nanoparticles have been deposited onto as-received and surface-modified G-CNFs. The surface modifications of the fibres comprise acid treatment and nitrogen doping by pyrolysis of a polyaniline...... (PANI) precursor. The modified surfaces were studied by FTIR and XPS and the electrochemical characterization, including long-term Pt stability tests, was performed using a low-temperature PEMFC single cell. The performance and stability of the G-CNF supported catalysts were compared with a CB supported...

  13. Stem cell differentiation on electrospun nanofibrous substrates for vascular tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Lin [Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, No. 2999 North Renmin Road, Songjiang, Shanghai 201620 (China); Center for Nanofibers and Nanotechnology, E3-05-14, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore); Prabhakaran, Molamma P., E-mail: nnimpp@nus.edu.sg [Center for Nanofibers and Nanotechnology, E3-05-14, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore); Qin, Xiaohong, E-mail: xhqin@dhu.edu.cn [Key Laboratory of Textile Science and Technology, Ministry of Education, College of Textiles, Donghua University, No. 2999 North Renmin Road, Songjiang, Shanghai 201620 (China); Ramakrishna, Seeram [Center for Nanofibers and Nanotechnology, E3-05-14, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore)

    2013-12-01

    Nanotechnology has enabled the engineering of a variety of materials to meet the current challenges and requirements in vascular tissue regeneration. In our study, poly-L-lactide (PLLA) and hybrid PLLA/collagen (PLLA/Coll) nanofibers (3:1 and 1:1) with fiber diameters of 210 to 430 nm were fabricated by electrospinning. Their morphological, chemical and mechanical characterizations were carried out using scanning electron microscopy (SEM), attenuated total reflectance Fourier transform infrared (ATR-FTIR), and tensile instrument, respectively. Bone marrow derived mesenchymal stem cells (MSCs) seeded on electrospun nanofibers that are capable of differentiating into vascular cells have great potential for repair of the vascular system. We investigated the potential of MSCs for vascular cell differentiation in vitro on electrospun PLLA/Coll nanofibrous scaffolds using endothelial differentiation media. After 20 days of culture, MSC proliferation on PLLA/Coll(1:1) scaffolds was found 256% higher than the cell proliferation on PLLA scaffolds. SEM images showed that the MSC differentiated endothelial cells on PLLA/Coll scaffolds showed cobblestone morphology in comparison to the fibroblastic type of undifferentiated MSCs. The functionality of the cells in the presence of ‘endothelial induction media’, was further demonstrated from the immunocytochemical analysis, where the MSCs on PLLA/Coll (1:1) scaffolds differentiated to endothelial cells and expressed the endothelial cell specific proteins such as platelet endothelial cell adhesion molecule-1 (PECAM-1 or CD31) and Von Willebrand factor (vWF). From the results of the SEM analysis and protein expression studies, we concluded that the electrospun PLLA/Coll nanofibers could mimic the native vascular ECM environment and might be promising substrates for potential application towards vascular regeneration. - Highlights: • PLLA and PLLA/Coll nanofibers were electrospun. • Incorporation of collagen reduced fiber

  14. The nanofibrous PAN-PANi scaffold as an efficient substrate for skeletal muscle differentiation using satellite cells.

    Science.gov (United States)

    Hosseinzadeh, Simzar; Mahmoudifard, Matin; Mohamadyar-Toupkanlou, Farzaneh; Dodel, Masomeh; Hajarizadeh, Atena; Adabi, Mahdi; Soleimani, Masoud

    2016-07-01

    Among polymers, polyaniline (PANi) has been introduced as a good candidate for muscle regeneration due to high conductivity and also biocompatibility. Herein, for the first time, we report the use of electrospun nanofibrous membrane of PAN-PANi as efficient scaffold for muscle regeneration. The prepared PAN-PANi electrospun nanofibrous membrane was characterized by scanning electron microscopy (SEM), Attenuated total reflectance fourier transform infrared spectroscopy (ATR-FTIR) and tensile examination. The softer scaffolds of non-composite electrospun nanofibrous PAN govern a higher rate of cell growth in spite of lower differentiation value. On the other hand, PAN-PANi electrospun nanofibrous membrane exposed high cell proliferation and also differentiation value. Thank to the conductive property and higher Young's modulus of composite type due to the employment of PANi, satellite cells were induced into more matured form as analyzed by Real-Time PCR. On the other hand, grafting of composite nanofibrous electrospun scaffold with gelatin increased the surface stiffness directing satellite cells into lower cell proliferation and highest value of differentiation. Our results for first time showed the significant role of combination between conductivity, mechanical property and surface modification of PAN-PANi electrospun nanofibers and provid new insights into most biocompatible scaffolds for muscle tissue engineering. The schematic figure conveys the effective combination of conductive and surface stiffness on muscle tissue engineering.

  15. Nanofibrous electrocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Di Jia; Shui, Jianglan; Chen, Chen

    2016-05-24

    A nanofibrous catalyst and method of manufacture. A precursor solution of a transition metal based material is formed into a plurality of interconnected nanofibers by electro-spinning the precursor solution with the nanofibers converted to a catalytically active material by a heat treatment. Selected subsequent treatments can enhance catalytic activity.

  16. Fabrication of ultra thin and aligned carbon nanofibres from electrospun polyacrylonitrile nanofibres

    Indian Academy of Sciences (India)

    Javed Rafique; Jie Yu; Xiaoxiong Zha; Khalid Rafique

    2010-10-01

    Ultra thin and aligned carbon nanofibres (CNFs) have been fabricated by heat treatment from aligned polyacrylonitrile (PAN) nanofibre precursors prepared by electrospinning. The alignment of the precursor nanofibres was achieved by using a modified electrospinning set up developed recently, where a tip collector was used to collect and align the nanofibres. The average diameter of the aligned CNFs is about 80 nm. The stabilization and carbonization behaviour were studied mainly based on the randomly oriented PAN nanofibres. The effects of stabilization and carbonization temperatures, temperature-increasing rates, and with and without substrates on the morphology and structure of the CNFs were investigated. Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, transmission electron microscopy and Raman spectroscopy were used to characterize the structure of the CNFs and thermogravimetric/differential temperature analysis was used to evaluate the thermal behaviour of PAN nanofibres.

  17. Supported Ag-TiO{sub 2} core-shell nanofibres formed at low temperature by plasma deposition

    Energy Technology Data Exchange (ETDEWEB)

    Borras, Ana; Barranco, Angel; Yubero, Francisco; Gonzalez-Elipe, Agustin R [Instituto de Ciencia de Materiales de Sevilla (CSIC-Univ. Sevilla), Avenida Americo Vespucio s/n, 41092 Sevilla (Spain)

    2006-07-28

    Ag-TiO{sub 2} nanofibres (about three {mu}m long and 30-150 nm thick) formed by a single-crystalline silver wire (20-30 nm thick) and an external layer of amorphous TiO{sub 2} of variable thickness are prepared at 403 K by oxygen plasma activation of a silver substrate followed by plasma deposition of TiO{sub 2}. Thicker fibres of anatase crystallites surrounding the silver wire were prepared when plasma deposition was carried out at 523 K. The fibres have been analysed by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and x-ray photoemission spectroscopy (XPS). The plasmon losses of the silver core wire have been characterized by electron energy loss spectroscopy in the TEM microscope. Based on the experimental evidence, a new volcano-type mechanism of formation of these core-shell fibres is proposed, whereby the effect of the plasma and the high mobility of the silver would be key factors determining their morphology and dimensions.

  18. Substrate-supported lipid nanotube arrays.

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, A. I.; Poluektov, O. G.; Chemistry; North Carolina State

    2003-07-16

    This Communication describes the self-assembly of phospholipids into lipid nanotubes inside nanoporous anodic aluminum oxide substrate. Orientations of the lipid molecules in such lipid nanoscale structures were verified by high-resolution spin labeling EPR at 95 GHz. The static order parameter of lipids in such nanotube arrays was determined from low-temperature EPR spectra and was found to be exceptionally high, S{sub static} {approx} 0.9. We propose that substrate-supported lipid nanotube arrays have potential for building robust biochips and biosensors in which rigid nanoporous substrates protect the bilayer surface from contamination. The total bilayer surface in the lipid nanotube arrays is much greater than that in the planar substrate-supported membranes. The lipid nanotube arrays seem to be suitable for developing patterned lipid deposition and could be potentially used for patterning of membrane-associated molecules.

  19. Synthesis of Bioactive Three-dimensional Silicon-oxide Nanofibrous Structures on the Silicon Substrate for Bionic Devices’ Fabrication

    Directory of Open Access Journals (Sweden)

    Candace Colpitts

    2016-02-01

    Full Text Available Bionic devices are implants that replace biological functions that have been lost due to damaged or lost tissue. The challenge of this area is to find the appropriate materials to match the biocompatible criteria with the same mechanical and electrical performance. In this research, a new method is introduced for the enhance‐ ment of silicon biocompatibility by fabrication of a 3D nanofibrous layer on the silicon surface, induced by nanosecond laser pulses at a high repetition rate and power. It was found that the laser treatment with small‐ er line spacing and a higher overlap number enhanced the biocompatibility of silicon. The results display a promis‐ ing improvement in the biocompatibility of silicon for the production of biomedical devices such as sensors, bio- MEMS and nano-biomaterial fabrications.

  20. Buckling Behavior of Substrate Supported Graphene Sheets

    Directory of Open Access Journals (Sweden)

    Kuijian Yang

    2016-01-01

    Full Text Available The buckling of graphene sheets on substrates can significantly degrade their performance in materials and devices. Therefore, a systematic investigation on the buckling behavior of monolayer graphene sheet/substrate systems is carried out in this paper by both molecular mechanics simulations and theoretical analysis. From 70 simulation cases of simple-supported graphene sheets with different sizes under uniaxial compression, two different buckling modes are investigated and revealed to be dominated by the graphene size. Especially, for graphene sheets with length larger than 3 nm and width larger than 1.1 nm, the buckling mode depends only on the length/width ratio. Besides, it is revealed that the existence of graphene substrate can increase the critical buckling stress and strain to 4.39 N/m and 1.58%, respectively, which are about 10 times those for free-standing graphene sheets. Moreover, for graphene sheets with common size (longer than 20 nm, both theoretical and simulation results show that the critical buckling stress and strain are dominated only by the adhesive interactions with substrate and independent of the graphene size. Results in this work provide valuable insight and guidelines for the design and application of graphene-derived materials and nano-electromechanical systems.

  1. Nanofibrous microfiltration membrane based on cellulose nanowhiskers.

    Science.gov (United States)

    Ma, Hongyang; Burger, Christian; Hsiao, Benjamin S; Chu, Benjamin

    2012-01-09

    A multilayered nanofibrous microfiltration (MF) membrane system with high flux, low pressure drop, and high retention capability against both bacteria and bacteriophages (a virus model) was developed by impregnating ultrafine cellulose nanowhiskers (diameter about 5 nm) into an electrospun polyacrylonitrile (PAN) nanofibrous scaffold (fiber diameter about 150 nm) supported by a poly(ethylene terephthalate) (PET) nonwoven substrate (fiber diameter about 20 μm). The cellulose nanowhiskers were anchored on the PAN nanofiber surface, forming a cross-linked nanostructured mesh with very high surface-to-volume ratio and a negatively charged surface. The mean pore size and pore size distribution of this MF system could be adjusted by the loading of cellulose nanowhiskers, where the resulting membrane not only possessed good mechanical properties but also high surface charge density confirmed by the conductivity titration and zeta potential measurements. The results indicated that a test cellulose nanowhisker-based MF membrane exhibited 16 times higher adsorption capacity against a positively charged dye over a commercial nitrocellulose-based MF membrane. This experimental membrane also showed full retention capability against bacteria, for example, E. coli and B. diminuta (log reduction value (LRV) larger than 6) and decent retention against bacteriophage MS2 (LRV larger than 2).

  2. Optical nanofibres and neutral atoms

    Science.gov (United States)

    Nieddu, Thomas; Gokhroo, Vandna; Chormaic, Síle Nic

    2016-05-01

    Optical nanofibres are increasingly being used in cold atom experiments due to their versatility and the clear advantages they have when developing all-fibred systems for quantum technologies. They provide researchers with a method of overcoming the Rayleigh range for achieving high intensities in a focussed beam over a relatively long distance, and can act as a noninvasive tool for probing cold atoms. In this review article, we will briefly introduce the theory of mode propagation in an ultrathin optical fibre and highlight some of the more significant theoretical and experimental progresses to date, including the early work on atom probing, manipulation and trapping, the study of atom-dielectric surface interactions, and the more recent observation of nanofibre-mediated nonlinear optics phenomena in atomic media. The functionality of optical nanofibres in relation to the realisation of atom-photon hybrid quantum systems is also becoming more evident as some of the earlier technical challenges are surpassed and, recently, several schemes to implement optical memories have been proposed. We also discuss some possible directions where this research field may head, in particular, in relation to the use of optical nanofibres that can support higher-order modes with an associated orbital angular momentum.

  3. Synthesis of bio-functionalized three-dimensional titania nanofibrous structures using femtosecond laser ablation.

    Science.gov (United States)

    Tavangar, Amirhossein; Tan, Bo; Venkatakrishnan, K

    2011-06-01

    The primary objective of current tissue regeneration research is to synthesize nano-based platforms that can induce guided, controlled, and rapid healing. Titanium nanotubes have been extensively considered as a new biomaterial for biosensors, implants, cell growth, tissue engineering, and drug delivery systems. However, due to their one-dimensional structure and chemical inertness, cell adhesion to nanotubes is poor. Therefore, further surface modification is required to enhance nanotube-cell interaction. Although there have been a considerable number of studies on growing titanium nanotubes, synthesizing a three-dimensional (3-D) nano-architecture which can act as a growth support platform for bone and stem cells has not been reported so far. Therefore, we present a novel technique to synthesize and grow 3-D titania interwoven nanofibrous structures on a titanium substrate using femtosecond laser irradiation under ambient conditions. This surface architecture incorporate the functions of 3-D nano-scaled topography and modified chemical properties to improve osseointegration while at the same time leaving space to deliver other functional agents. The results indicate that laser pulse repetition can control the density and pore size of engineered nanofibrous structures. In vitro experiments reveal that the titania nanofibrous architecture possesses excellent bioactivity and can induce rapid, uniform, and controllable bone-like apatite precipitation once immersed in simulated body fluid (SBF). This approach to synthesizing 3-D titania nanofibrous structures suggests considerable promise for the promotion of Ti interfacial properties to develop new functional biomaterials for various biomedical applications.

  4. Nanofibrous scaffolds for dental and craniofacial applications.

    Science.gov (United States)

    Gupte, M J; Ma, P X

    2012-03-01

    Tissue-engineering solutions often harness biomimetic materials to support cells for functional tissue regeneration. Three-dimensional 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 scaffold synthesis/fabrication, biological effects of nanofibers, their tissue- engineering applications in bone, cartilage, enamel, dentin, and periodontium, patient-specific scaffolds, and incorporated growth factor delivery systems. Nanofibrous scaffolds cannot only further the field of craniofacial regeneration but also advance technology for tissue-engineered replacements in many physiological systems.

  5. Wrinkling of graphene membranes supported by silica nanoparticles on substrates

    Science.gov (United States)

    Yamamoto, Mahito; Cullen, William; Fuhrer, Michael; Einstein, Theodore; Department of Physics, University of Maryland Team

    2011-03-01

    The challenging endeavor of modulating the morphology of graphene via a patterned substrate to produce a controlled deformation has great potential importance for strain engineering the electronic properties of graphene. An essential step in this direction is to understand the response of graphene to substrate features of known geometry. Here we employ silica nanoparticles with a diameter of 10-100 nm to uniformly decorate Si O2 and mica substrates before depositing graphene, to promote nanoscale modulation of graphene geometry. The morphology of graphene on this modified substrate is then characterized by atomic force spectroscopy. We find that graphene on the substrate is locally raised by the supporting nanoparticles, and wrinkling propagates radially from the protrusions to form a ridge network which links the protrusions. We discuss the dependence of the wrinkled morphology on nanoparticle diameter and graphene thickness in terms of graphene elasticity and adhesion energy. Supported by NSF-MRSEC, Grant DMR 05-20471

  6. Synthesis of Y-junction carbon nanofibres by ethanol catalytic combustion technique

    Institute of Scientific and Technical Information of China (English)

    LI Fei; ZOU Xiao-ping; CHENG Jin; ZHANG Hong-dan; REN Peng-fei

    2006-01-01

    Y-shaped structure was synthesized by ethanol catalytic combustion(ECC) technique on the copper plate substrate,without directly seeding catalyst into the flame. The as-grown Y-junction carbon nanofibres were investigated by transmission electron microscopy (TEM). The very common laboratory ethanol burner was used for synthesizing carbon nanofibres. Two kinds of the catalyst precursor,which are iron nitrate (Fe(NO3)3) and nickel nitrate (Ni(NO3)2),were respectively employed to assist the formation of Y-junction carbon nanofibres. TEM analysis confirm the formation of Y-junction in the coiled and noncoiled carbon nanofibres. The type of the catalyst is found to be crucial to grow different Y-junction carbon nanofibres. Different Y-shaped structure may possess different mechanical and electronic properties. These three-terminal nanofibres provide the nanoelectronics community with a novel material for the development of molecular-scale electronic devices.

  7. Bioceramic Nanofibres by Electrospinning

    Directory of Open Access Journals (Sweden)

    Rajkamal Balu

    2014-08-01

    Full Text Available Nanoscale three-dimensional (3D scaffolds offer great promise for improved tissue integration and regeneration by their physical and chemical property enhancements. Electrospinning is a versatile bottom-up technique for producing porous 3D nanofibrous scaffolds that could closely mimic the structure of extracellular matrix. Much work has been committed to the development of this process through the years, and the resultant nanostructures have been subjugated to a wide range of applications in the field of bioengineering. In particular, the application of ceramic nanofibres in hard tissue engineering, such as dental and bone regeneration, is of increased research interest. This mini-review provides a brief overview of the bioceramic nanofibre scaffolds fabricated by electrospinning and highlights some of the significant process developments over recent years with their probable future trends and potential applications as biomedical implants.

  8. Dynamic culture of osteogenic cells in biomimetically coated poly(caprolactone) nanofibre mesh constructs.

    Science.gov (United States)

    Araujo, Jose V; Cunha-Reis, Cassilda; Rada, Tommaso; da Silva, Marta Alves; Gomes, Manuela E; Yang, Ying; Ashammakhi, Nureddin; Reis, Rui L; El-Haj, Alicia J; Neves, Nuno M

    2010-02-01

    In our previous work, biomimetic calcium phosphate-coated poly(caprolactone) nanofibre meshes (BCP-NMs) were demonstrated to be more effective for supporting cell attachment and proliferation under static conditions, when compared with poly(caprolactone) nanofibre meshes (PCL-NMs). In many applications, in vitro cultivation of constructs using bioreactors that support efficient nutrition of cells has appeared as an important step toward the development of functional grafts. This work aimed at studying the effects of dynamic culture conditions and biomimetic coating on bone cells grown on the nanofibre meshes. BCP-NM and PCL-NM were seeded with osteoblast-like cells (MG63--human osteosarcoma-derived cell line). The cell-seeded constructs were cultured within a rotating bioreactor that simulated microgravity, at a fixed rotating speed, for different time periods, and then characterized. Cell morphology, viability, and phenotype were assessed. PCL-NM constructs presented a higher number of dead cells than BCP-NM constructs. Under dynamic conditions, the production of proteins associated with the extracellular matrix of bone was higher on BCP-NM constructs than in the PCL-NM ones, which indicates that coated samples may provide cells with a better environment for tissue growth. It is suggested that improved mass transfer in the bioreactor in combination with the appropriate substrate were decisive factors for this highly positive outcome for generating bone.

  9. Direct-writing organic three-dimensional nanofibrous structure

    Science.gov (United States)

    Wang, Han; Zheng, Gaofeng; Li, Wenwang; Wang, Xiang; Sun, Daoheng

    2011-02-01

    Direct-writing technology based on Near-Field Electrospinning (NFES) was used to fabricate an organic three-dimensional nanofibrous circle on the patterned silicon substrate. In NFES, straight jet without splitting and chaotic motion was utilized to direct-write orderly nanofiber. When the collector movement speed was lower than electrospinning rate, the relaxed nanofiber would be lead into the pendulum motion by the electrical field force and Coulomb repulsion force from the residual charges on the collector. When the relative air humidity is lower than 35%, individual nanofiber with larger elastic resistance would reveal a good self-assembly performance. Owing to the guidance of the electric field force at the edge of the micro-pattern, a nanofiber was deposited layer by layer to format a 3D nanofibrous circle on the top surface of the micro-pattern. The dimension scale of 3D nanofibrous circle was smaller than 30 µm. With the help of a microscope, a 3D nanofibrous circle can be deposited precisely on the strip micro-pattern with width of 4 µm. Furthermore, a 3D nanofibrous circle in different shapes can be obtained by using special micro-patterns. This organic three-dimensional nanofibrous circle has created a new aspect for the fabrication of organic micro/nanosystems.

  10. A Nanofibre Tag

    DEFF Research Database (Denmark)

    Radziwon, Michal Jędrzej; Johansen, Stefan; Rubahn, Horst-Günter

    on stochastic generation of marking templates. Difficulty of manual manipulation of nanofibres, together with simplicity of their optical examination, makes them preferred candidates for such applications. Fibres obtained by molecular beam epitaxy of parahexaphenylene (p6P), form a unique pattern, which can...

  11. Crosslinked gelatin nanofibres: Preparation, characterisation and in vitro studies using glial-like cells

    Energy Technology Data Exchange (ETDEWEB)

    Tonda-Turo, C. [Politecnico di Torino, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino (Italy); Cipriani, E. [Nanostructured Interfaces and Surfaces (NIS) Centre of Excellence, Department of Chemistry IFM, Università di Torino, Via P. Giuria 7, Torino (Italy); Gnavi, S. [Department Of Human and Animal Biology, Università di Torino, Via Accademia Albertina, 23, Torino (Italy); Chiono, V.; Mattu, C.; Gentile, P. [Politecnico di Torino, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino (Italy); Perroteau, I. [Department Of Human and Animal Biology, Università di Torino, Via Accademia Albertina, 23, Torino (Italy); Zanetti, M. [Nanostructured Interfaces and Surfaces (NIS) Centre of Excellence, Department of Chemistry IFM, Università di Torino, Via P. Giuria 7, Torino (Italy); Ciardelli, G., E-mail: gianluca.ciardelli@polito.it [Politecnico di Torino, Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, Torino (Italy); CNR-IPCF UOS Pisa Via Moruzzi, 1, 56124 Pisa (Italy)

    2013-07-01

    Gelatin (GL) nanofibrous matrices mimicking the complex biological structure of the natural extracellular matrix (ECM) were prepared from aqueous solutions by electrospinning technique. GL nanofibres with a diameter size of around 300 nm were obtained optimising the process and solution parameters. To increase the GL stability in aqueous environment γ-glycidoxypropyltrimethoxysilane (GPTMS) was used as GL crosslinker. GPTMS crosslinking did not modify the nanofibrous matrix morphology: fibre diameter and membrane pores size were 327 ± 45 nm and 1.64 ± 0.37 μm, respectively. The produced GPTMS crosslinked GL nanofibres (GL/GPTMS{sub N}F) were found to support the in vitro adhesion, proliferation and survival of neonatal olfactory bulb ensheating cells (NOBECs). - Highlights: • Gelatin nanofibres were prepared from aqueous solution. • A silane-coupling agent was used as gelatin crosslinker. • Glial-like cells adhered and proliferated on the developed nanofibres. • Elongated morphology of glial-like cells was observed.

  12. Cellulose Nanofibre Mesh for Use in Dental Materials

    Directory of Open Access Journals (Sweden)

    Anthony J. Ireland

    2012-07-01

    Full Text Available The aim of this study was to produce a 3D mesh of defect free electrospun cellulose acetate nanofibres and to use this to produce a prototype composite resin containing nanofibre fillers. This might find use as an aesthetic orthodontic bracket material or composite veneer for restorative dentistry. In this laboratory based study cellulose acetate was dissolved in an acetone and dimethylacetamide solvent solution and electrospun. The spinning parameters were optimised and lithium chloride added to the solution to produce a self supporting nanofibre mesh. This mesh was then silane coated and infiltrated with either epoxy resin or an unfilled Bis-GMA resin. The flexural strength of the produced samples was measured and compared to that of unfilled resin samples. Using this method cellulose acetate nanofibres were successfully electrospun in the 286 nm range. However, resin infiltration of this mesh resulted in samples with a flexural strength less than that of the unfilled control samples. Air inclusion during preparation and incomplete wetting of the nanofibre mesh was thought to cause this reduction in flexural strength. Further work is required to reduce the air inclusions before the true effect of resin reinforcement with a 3D mesh of cellulose acetate nanofibres can be determined.

  13. Engineering Bi-Layer Nanofibrous Conduits for Peripheral Nerve Regeneration

    Science.gov (United States)

    Zhu, Yiqian; Wang, Aijun; Patel, Shyam; Kurpinski, Kyle; Diao, Edward; Bao, Xuan; Kwong, George; Young, William L.

    2011-01-01

    Trauma injuries often cause peripheral nerve damage and disability. A goal in neural tissue engineering is to develop synthetic nerve conduits for peripheral nerve regeneration having therapeutic efficacy comparable to that of autografts. Nanofibrous conduits with aligned nanofibers have been shown to promote nerve regeneration, but current fabrication methods rely on rolling a fibrous sheet into the shape of a conduit, which results in a graft with inconsistent size and a discontinuous joint or seam. In addition, the long-term effects of nanofibrous nerve conduits, in comparison with autografts, are still unknown. Here we developed a novel one-step electrospinning process and, for the first time, fabricated a seamless bi-layer nanofibrous nerve conduit: the luminal layer having longitudinally aligned nanofibers to promote nerve regeneration, and the outer layer having randomly organized nanofibers for mechanical support. Long-term in vivo studies demonstrated that bi-layer aligned nanofibrous nerve conduits were superior to random nanofibrous conduits and had comparable therapeutic effects to autografts for nerve regeneration. In summary, we showed that the engineered nanostructure had a significant impact on neural tissue regeneration in situ. The results from this study will also lead to the scalable fabrication of engineered nanofibrous nerve conduits with designed nanostructure. This technology platform can be combined with drug delivery and cell therapies for tissue engineering. PMID:21501089

  14. Carbon nanofibre composites, preparation and use, EP application 04076211.4

    NARCIS (Netherlands)

    2005-01-01

    The invention is directed to a carbon nanofibre composite having a bulk density of at least 800kg/m3, obtainable by the process of growing carbon nanofibres on the surface of a supported carbon fibre producing metal catalyst, such as a catalyst based on nickel, cobalt, iron, ruthenium or combination

  15. Method of forming through substrate vias (TSVs) and singulating and releasing die having the TSVs from a mechanical support substrate

    Science.gov (United States)

    Okandan, Murat; Nielson, Gregory N

    2014-12-09

    Accessing a workpiece object in semiconductor processing is disclosed. The workpiece object includes a mechanical support substrate, a release layer over the mechanical support substrate, and an integrated circuit substrate coupled over the release layer. The integrated circuit substrate includes a device layer having semiconductor devices. The method also includes etching through-substrate via (TSV) openings through the integrated circuit substrate that have buried ends at or within the release layer including using the release layer as an etch stop. TSVs are formed by introducing one or more conductive materials into the TSV openings. A die singulation trench is etched at least substantially through the integrated circuit substrate around a perimeter of an integrated circuit die. The integrated circuit die is at least substantially released from the mechanical support substrate.

  16. A carbon nanofibre scanning probe assembled using an electrothermal microgripper

    DEFF Research Database (Denmark)

    Carlson, Kenneth; Dyvelkov, Karin Nordström; Eicchorn, V.

    2007-01-01

    Functional devices can be directly assembled using microgrippers with an in situ electron microscope. Two simple and compact silicon microgripper designs are investigated here. These are operated by electrothermal actuation, and are used to transfer a catalytically grown multi-walled carbon...... nanofibre from a fixed position on a substrate to the tip of an atomic force microscope cantilever, inside a scanning electron microscope. Scanning of high aspect ratio trenches using the nanofibre supertip shows a significantly better performance than that with standard pyramidal silicon tips. Based...

  17. Room and low temperature synthesis of carbon nanofibres

    CERN Document Server

    Boskovic, B O

    2002-01-01

    Carbon nanotubes and nanofibres have attracted attention in recent years as new materials with a number of very promising potential applications. Carbon nanotubes are potential candidates for field emitters in flat panel displays. Carbon nanofibres could also be used as a hydrogen storage material and as a filling material in polymer composites. Carbon nanotubes are already used as tips in scanning probe microscopy due to their remarkable mechanical and electrical properties, and could be soon used as nanotweezers. Use of carbon nanotubes in nanoelectronics will open further miniaturisation prospects. Temperatures ranging from 450 to 1000 deg C have been a required for catalytic growth of carbon nanotubes and nanofibres. Researchers have been trying to reduce the growth temperatures for decades. Low temperature growth conditions will allow the growth of carbon nanotubes on different substrates, such glass (below 650 deg C) and as plastics (below 150 deg C) over relatively large areas, which is especially suit...

  18. Nanofibrous Silver-Coated Polymeric Scaffolds with Tunable Electrical Properties

    Directory of Open Access Journals (Sweden)

    Adnan Memic

    2017-03-01

    Full Text Available Electrospun micro- and nanofibrous poly(glycerol sebacate-poly(ε-caprolactone (PGS-PCL substrates have been extensively used as scaffolds for engineered tissues due to their desirable mechanical properties and their tunable degradability. In this study, we fabricated micro/nanofibrous scaffolds from a PGS-PCL composite using a standard electrospinning approach and then coated them with silver (Ag using a custom radio frequency (RF sputtering method. The Ag coating formed an electrically conductive layer around the fibers and decreased the pore size. The thickness of the Ag coating could be controlled, thereby tailoring the conductivity of the substrate. The flexible, stretchable patches formed excellent conformal contact with surrounding tissues and possessed excellent pattern-substrate fidelity. In vitro studies confirmed the platform’s biocompatibility and biodegradability. Finally, the potential controlled release of the Ag coating from the composite fibrous scaffolds could be beneficial for many clinical applications.

  19. Fabrication and Characterization of Thermoresponsive Polystyrene Nanofibrous Mats for Cultured Cell Recovery

    Science.gov (United States)

    Oh, Hwan Hee; Uyama, Hiroshi; Park, Won Ho; Cho, Donghwan; Kwon, Oh Hyeong

    2014-01-01

    Rapid cell growth and rapid recovery of intact cultured cells are an invaluable technique to maintain the biological functions and viability of cells. To achieve this goal, thermoresponsive polystyrene (PS) nanofibrous mat was fabricated by electrospinning of PS solution, followed by the graft polymerization of thermoresponsive poly(N-isopropylacrylamide)(PIPAAm) on PS nanofibrous mats. Image analysis of the PS nanofiber revealed a unimodal distribution pattern with 400 nm average fiber diameter. Graft polymerization of PIPAAm on PS nanofibrous mats was confirmed by spectroscopic methods such as ATR-FTIR, ESCA, and AFM. Human fibroblasts were cultured on four different surfaces, PIPAAm-grafted and ungrafted PS dishes and PIPAAm-grafted and ungrafted PS nanofibrous mats, respectively. Cells on PIPAAm-grafted PS nanofibrous mats were well attached, spread, and proliferated significantly much more than those on other surfaces. Cultured cells were easily detached from the PIPAAm-grafted surfaces by decreasing culture temperature to 20°C, while negligible cells were detached from ungrafted surfaces. Moreover, cells on PIPAAm-grafted PS nanofibrous mats were detached more rapidly than those on PIPAAm-grafted PS dishes. These results suggest that thermoresponsive nanofibrous mats are attractive cell culture substrates which enable rapid cell growth and recovery from the culture surface for application to tissue engineering and regenerative medicine. PMID:24696851

  20. Fabrication and Characterization of Thermoresponsive Polystyrene Nanofibrous Mats for Cultured Cell Recovery

    Directory of Open Access Journals (Sweden)

    Hwan Hee Oh

    2014-01-01

    Full Text Available Rapid cell growth and rapid recovery of intact cultured cells are an invaluable technique to maintain the biological functions and viability of cells. To achieve this goal, thermoresponsive polystyrene (PS nanofibrous mat was fabricated by electrospinning of PS solution, followed by the graft polymerization of thermoresponsive poly(N-isopropylacrylamide(PIPAAm on PS nanofibrous mats. Image analysis of the PS nanofiber revealed a unimodal distribution pattern with 400 nm average fiber diameter. Graft polymerization of PIPAAm on PS nanofibrous mats was confirmed by spectroscopic methods such as ATR-FTIR, ESCA, and AFM. Human fibroblasts were cultured on four different surfaces, PIPAAm-grafted and ungrafted PS dishes and PIPAAm-grafted and ungrafted PS nanofibrous mats, respectively. Cells on PIPAAm-grafted PS nanofibrous mats were well attached, spread, and proliferated significantly much more than those on other surfaces. Cultured cells were easily detached from the PIPAAm-grafted surfaces by decreasing culture temperature to 20°C, while negligible cells were detached from ungrafted surfaces. Moreover, cells on PIPAAm-grafted PS nanofibrous mats were detached more rapidly than those on PIPAAm-grafted PS dishes. These results suggest that thermoresponsive nanofibrous mats are attractive cell culture substrates which enable rapid cell growth and recovery from the culture surface for application to tissue engineering and regenerative medicine.

  1. Fabrication and application of nanofibrous scaffolds in tissue engineering.

    Science.gov (United States)

    Li, Wan-Ju; Tuan, Rocky S

    2009-03-01

    Nanofibers fabricated by electrospinning are morphological mimics of fibrous components of the native extracellular matrix, making nanofibrous scaffolds ideal for three-dimensional cell culture and tissue engineering applications. Although electrospinning is not a conventional technique in cell biology, the experimental setup may be constructed in a relatively straightforward manner, and the procedure can be carried out by individuals with limited engineering experience. Here, we detail a protocol for electrospinning of nanofibers and provide relevant specific details concerning the optimization of fiber formation (Basic Protocol 1). The protocol also includes conditions required for preparing biodegradable polymer solutions for the fabrication of nonwoven and aligned nanofibrous scaffolds suitable for various cell/tissue applications. In addition, information on effective cell loading into nanofibrous scaffolds and cellular constructs grown in a bioreactor is provided (Basic Protocol 2). Instructions for building the electrospinning apparatus are also included (see the Support Protocol).

  2. Electrospun aligned nanofibrous composite of MWCNT/polyurethane to enhance vascular endothelium cells proliferation and function.

    Science.gov (United States)

    Meng, Jie; Han, Zhaozhao; Kong, Hua; Qi, Xiaojin; Wang, Chaoying; Xie, Sishen; Xu, Haiyan

    2010-10-01

    Aligned or random nanofibrous meshes of multiwalled carbon nanotubes/polyurethane composite (MWCNT/PU) were fabricated by electrospinning and characterized by scanning electron microscopy (SEM). The regulatory effects of nanofibrous structure and MWCNT on the growth and anticoagulant function of human umbilical vein endothelial cells (HUVECs) were investigated by examining proliferation, type IV collagen secretion, tissue factor and plasminogen activator inhibitor-1 (PAI-1) release, and cytoskeleton arrangement, as well as via pull-down analysis. We show that aligned nanofibrous structure and MWCNT can function as extracellular signals to stimulate cell growth, proliferation, and extracellular collagen secretion, in addition to preserving anticoagulant function. The nanofibrous structures played important roles in the activation of Rac and Cdc42, while CNT regulated the activation of Rho. These two features synergistically activated Rho GTPases that transmitted cell-substrate signals to the cytoplasm. These signals were then relayed to the nucleus by the MAP kinase pathway to direct cytoskeletal arrangement and cell orientation.

  3. Aligned and random nanofibrous nanocomposite scaffolds for bone tissue engineering

    Directory of Open Access Journals (Sweden)

    Amir Doustgani

    2013-01-01

    Full Text Available Abstract  Aligned and random nanocomposite nanofibrous scaffolds were electrospun from polycaprolactone (PCL, poly (vinyl alcohol (PVA and hydroxyapatite nanoparticles (nHA. The morphology and mechanical characteristics of the nanofibers were evaluated using scanning electron microscopy and tensile testing, respectively. Scanning electron microscopy revealed fibers with an average diameter of 123 ± 32 nm and 339 ± 107 nm for aligned and random nanofibers, respectively. The mechanical data indicated the higher tensile strength and elastic modulus of aligned nanofibers. The in vitro biocompatibility of aligned and random nanofibrous scaffolds was also assessed by growing mesenchymal stem cells (MSCs, and investigating the proliferation and alkaline phosphatase activity (ALP on different nanofibrous scaffolds. Our  findings  showed  that  the  alignment  orientation  of  nanofibers  enhanced  the osteogenic differentiation of stem cells. The in vitro results showed that the aligned biocomposite nanofibrous scaffolds of PCL/nHA/PVA could be a potential substrate for tissue engineering applications, especially in the field of artificial bone implant.

  4. Electrospun biocomposite nanofibrous patch for cardiac tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Prabhakaran, Molamma P; Ramakrishna, Seeram [Health Care and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 2 Engineering Drive 3, Singapore 117576 (Singapore); Kai, Dan [NUS Graduate School of Integrative Sciences and Engineering, National University of Singapore (Singapore); Ghasemi-Mobarakeh, Laleh, E-mail: nnimpp@nus.edu.s [Islamic Azad University, Najafabad Branch, Isfahan (Iran, Islamic Republic of)

    2011-10-15

    A bioengineered construct that matches the chemical, mechanical, biological properties and extracellular matrix morphology of native tissue could be suitable as a cardiac patch for supporting the heart after myocardial infarction. The potential of utilizing a composite nanofibrous scaffold of poly(dl-lactide-co-glycolide)/gelatin (PLGA/Gel) as a biomimetic cardiac patch is studied by culturing a population of cardiomyocyte containing cells on the electrospun scaffolds. The chemical characterization and mechanical properties of the electrospun PLGA and PLGA/Gel nanofibers were studied by Fourier transform infrared spectroscopy, scanning electron microscopy and tensile measurements. The biocompatibility of the scaffolds was also studied and the cardiomyocytes seeded on PLGA/Gel nanofibers were found to express the typical functional cardiac proteins such as alpha-actinin and troponin I, showing the easy integration of cardiomyocytes on PLGA/Gel scaffolds. Our studies strengthen the application of electrospun PLGA/Gel nanofibers as a bio-mechanical support for injured myocardium and as a potential substrate for induction of endogenous cardiomyocyte proliferation, ultimately reducing the cardiac dysfunction and improving cardiac remodeling.

  5. Optical nanofibres and neutral atoms

    CERN Document Server

    Nieddu, Thomas; Chormaic, Sile Nic

    2015-01-01

    Optical nanofibres are increasingly being used in cold atom experiments due to their versatility and the clear advantages they have when developing all-fibred systems for quantum technologies. They provide researchers with a method of overcoming the Rayleigh range for achieving high intensities in a focussed beam over a relatively long distance, and can act as a noninvasive tool for probing cold atoms. In this review article, we will briefly introduce the theory of mode propagation in an ultrathin optical fibre and highlight some of the more significant theoretical and experimental progresses to date, including the early work on atom probing, manipulation and trapping, the study of atom-dielectric surface interactions, and the more recent observation of nanofibre-mediated nonlinear optics phenomena in atomic media. The functionality of optical nanofibres in relation to the realisation of atom-photon hybrid quantum systems is also becoming more evident as some of the earlier technical challenges are surpassed ...

  6. Energy substrates to support glutamatergic and GABAergic synaptic function

    DEFF Research Database (Denmark)

    Schousboe, Arne; Bak, Lasse K; Sickmann, Helle M;

    2007-01-01

    Maintenance of glutamatergic and GABAergic activity requires a continuous supply of energy since the exocytotic processes as well as high affinity glutamate and GABA uptake and subsequent metabolism of glutamate to glutamine are energy demanding processes. The main energy substrate for the brain ...

  7. Biologically improved nanofibrous scaffolds for cardiac tissue engineering.

    Science.gov (United States)

    Bhaarathy, V; Venugopal, J; Gandhimathi, C; Ponpandian, N; Mangalaraj, D; Ramakrishna, S

    2014-11-01

    Nanofibrous structure developed by electrospinning technology provides attractive extracellular matrix conditions for the anchorage, migration and differentiation of stem cells, including those responsible for regenerative medicine. Recently, biocomposite nanofibers consisting of two or more polymeric blends are electrospun more tidily in order to obtain scaffolds with desired functional and mechanical properties depending on their applications. The study focuses on one such an attempt of using copolymer Poly(l-lactic acid)-co-poly (ε-caprolactone) (PLACL), silk fibroin (SF) and Aloe Vera (AV) for fabricating biocomposite nanofibrous scaffolds for cardiac tissue engineering. SEM micrographs of fabricated electrospun PLACL, PLACL/SF and PLACL/SF/AV nanofibrous scaffolds are porous, beadless, uniform nanofibers with interconnected pores and obtained fibre diameter in the range of 459 ± 22 nm, 202 ± 12 nm and 188 ± 16 nm respectively. PLACL, PLACL/SF and PLACL/SF/AV electrospun mats obtained at room temperature with an elastic modulus of 14.1 ± 0.7, 9.96 ± 2.5 and 7.0 ± 0.9 MPa respectively. PLACL/SF/AV nanofibers have more desirable properties to act as flexible cell supporting scaffolds compared to PLACL for the repair of myocardial infarction (MI). The PLACL/SF and PLACL/SF/AV nanofibers had a contact angle of 51 ± 12° compared to that of 133 ± 15° of PLACL alone. Cardiac cell proliferation was increased by 21% in PLACL/SF/AV nanofibers compared to PLACL by day 6 and further increased to 42% by day 9. Confocal analysis for cardiac expression proteins myosin and connexin 43 was observed better by day 9 compared to all other nanofibrous scaffolds. The results proved that the fabricated PLACL/SF/AV nanofibrous scaffolds have good potentiality for the regeneration of infarcted myocardium in cardiac tissue engineering.

  8. Enhancement of nanofibrous scaffold of multiwalled carbon nanotubes/polyurethane composite to the fibroblasts growth and biosynthesis.

    Science.gov (United States)

    Meng, Jie; Kong, Hua; Han, Zhaozhao; Wang, Chaoying; Zhu, Guangjin; Xie, Sishen; Xu, Haiyan

    2009-01-01

    In this work, the effect of nanofibrous structure and multiwalled carbon nanotubes (MWNTs) incorporation in the polyurethane (PU) on the fibroblasts growth behavior was studied. The nanofibrous scaffold of multiwalled carbon nanotubes and polyurethane composite (MWNT/PU) with an average fiber diameter of 300-500 nm was fabricated by electrospinning technique. The nanofibrous scaffold of PU, smooth film of PU, and MWNT/PU were also prepared as controls. Cell viability assay, laser confocal microscopy, and scanning electron microscopy were applied to evaluate cell adhesion, proliferation, and cytoskeletal development on the scaffolds, respectively. Cell-released protein was analyzed by Bradford protein assay, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), mass spectrometry, and transwell assay, respectively. Experimental results demonstrated that the scaffold with nanofibrous structure and MWNTs incorporation exhibited highest enhancement not only to the cell adhesion and proliferation but also to the cell migration and aggregation. Besides, cells cultured on the nanofibrous scaffold of MWNT/PU released the largest amount of proteins including collagen in comparison with those on the other substrates. Hence, the nanofibrous architecture and MWNTs incorporation provided favorite interactions to the cells, which implied the application potentials of the nanofibrous composite for tissue repair and regeneration.

  9. Immobilization and Properties of Lipase from Candida rugosa on Electrospun Nanofibrous Membranes with Biomimetic Phospholipid Moities

    Institute of Scientific and Technical Information of China (English)

    HUANG Xiao-jun; YU An-guo; GE Dan; XU Zhi-kang

    2008-01-01

    Reported here is a protocol to fabricate a biocatalyst with high enzyme loading and activity retention,from the conjugation of electrospun nanofibrous membrane having biomimetic phospholipid moiety and lipase.To improve the catalytic efficiency and activity of the immobilized enzyme,poly(acrylonitrile-co-2-methacryloyloxyethyl phosphorylcholine)s(PANCMPCs)were,respectively,electrospun into nanofibrous membranes with a mean diameter of 90 nm,as a support for enzyme immobilization.Lipase from Candida rugosa Was immobilized on these nanofibrous membranes by adsorption.Properties of immobilized lipase on PANCMPC nanofibrous membranes were compared with those of the lipase immobilized on the polyacrylonitrile(PAN)nanofibrous and sheet membranes,respectively.Efiective enzyme loading on the nanofibrous membranes was achieved up to22mg/g,which was over 10times that on the sheet membrane.The activity retention of immobilized lipase increased from 56.4%to 76.8%with an increase in phospholipid moiety from 0 to 9.6%(molar fraction)in the nanofibrous membrane.Kinetic parameter Km was also determined for free and immobilized lipase.The Km valae of the immobilized lipase on the nanofibrous membrane was obviously lower than that on the sheet membrane.The optimum pH was 7.7 for free lipase.but shifted to 8.3-8.5 for immobilized lipases.The optimum temperature was determined to be 35℃ for the free enzyme.but 42-44℃ for the immobilized ones,respectively.In addition,the thermal stability,reusability,and storage stability of the immobilized lipase were obviously improved compared to the free one.

  10. Thermal treatment for nanofibrous membrane

    Directory of Open Access Journals (Sweden)

    Liu Hong-Ying

    2014-01-01

    Full Text Available Poly(vinylidene fluoride nanofibrous membranes with high porosity, large electrolyte solution uptake, and adequate mechanical properties were prepared by electrospinning. The physical properties of the electrospun poly(vinylidene fluoride membranes can be improved by thermal treatment. Results showed after the thermal treatment, there had appeared ever-increasing tensile strength and elongation of the poly(vinylidene fluoride membranes. The crystal structures of poly(vinylidene fluoride fibers were greatly improved.

  11. Biocomposite nanofibrous strategies for the controlled release of biomolecules for skin tissue regeneration.

    Science.gov (United States)

    Gandhimathi, Chinnasamy; Venugopal, Jayarama Reddy; Bhaarathy, Velmurugan; Ramakrishna, Seeram; Kumar, Srinivasan Dinesh

    2014-01-01

    Nanotechnology and tissue engineering have enabled engineering of nanostructured strategies to meet the current challenges in skin tissue regeneration. Electrospinning technology creates porous nanofibrous scaffolds to mimic extracellular matrix of the native tissues. The present study was performed to gain some insights into the applications of poly(l-lactic acid)-co-poly-(ε-caprolactone) (PLACL)/silk fibroin (SF)/vitamin E (VE)/curcumin (Cur) nanofibrous scaffolds and to assess their potential for being used as substrates for the culture of human dermal fibroblasts for skin tissue engineering. PLACL/SF/VE/Cur nanofibrous scaffolds were fabricated by electrospinning and characterized by fiber morphology, membrane porosity, wettability, mechanical strength, and chemical properties by Fourier transform infrared (FTIR) analysis. Human dermal fibroblasts were cultured on these scaffolds, and the cell scaffold interactions were analyzed by cell proliferation, cell morphology, secretion of collagen, expression of F-actin, and 5-chloromethylfluorescein diacetate (CMFDA) dye. The electrospun nanofiber diameter was obtained between 198±4 nm and 332±13 nm for PLACL, PLACL/SF, PLACL/SF/VE, and PLACL/SF/VE/Cur nanofibrous scaffolds. FTIR analysis showed the presence of the amide groups I, II, and III, and a porosity of up to 92% obtained on these nanofibrous scaffolds. The results showed that the fibroblast proliferation, cell morphology, F-actin, CMFDA dye expression, and secretion of collagen were significantly increased in PLACL/SF/VE/Cur when compared to PLACL nanofibrous scaffolds. The accessibility of human dermal fibroblasts cultured on PLACL/SF/VE/Cur nanofibrous scaffolds proved to be a potential scaffold for skin tissue regeneration.

  12. Electrical stimulation of nerve cells using conductive nanofibrous scaffolds for nerve tissue engineering.

    Science.gov (United States)

    Ghasemi-Mobarakeh, Laleh; Prabhakaran, Molamma P; Morshed, Mohammad; Nasr-Esfahani, Mohammad Hossein; Ramakrishna, Seeram

    2009-11-01

    Fabrication of scaffolds with suitable chemical, mechanical, and electrical properties is critical for the success of nerve tissue engineering. Electrical stimulation was directly applied to electrospun conductive nanofibrous scaffolds to enhance the nerve regeneration process. In the present study, electrospun conductive nanofibers were prepared by mixing 10 and 15 wt% doped polyaniline (PANI) with poly (epsilon-caprolactone)/gelatin (PG) (70:30) solution (PANI/PG) by electrospinning. The fiber diameter, pore size, hydrophilicity, tensile properties, conductivity, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy spectra of nanofibers were determined, and the in vitro biodegradability of the different nanofibrous scaffolds was also evaluated. Nanofibrous scaffolds containing 15% PANI was found to exhibit the most balanced properties to meet all the required specifications for electrical stimulation for its enhanced conductivity and is used for in vitro culture and electrical stimulation of nerve stem cells. 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and scanning electron microscopy results showed that conductive nanofibrous scaffolds are suitable substrates for the attachment and proliferation of nerve stem cells. Electrical stimulation through conductive nanofibrous PANI/PG scaffolds showed enhanced cell proliferation and neurite outgrowth compared to the PANI/PG scaffolds that were not subjected to electrical stimulation.

  13. Biologically improved nanofibrous scaffolds for cardiac tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Bhaarathy, V. [Centre for Nanofibers and Nanotechnology, NUSNNI, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Department of Nanoscience and Technology, School of Physical Sciences, Bharathiar University, Coimbatore 641046 (India); Lee Kong Chian School of Medicine, Nanyang Technological University, 138673 (Singapore); Venugopal, J., E-mail: nnijrv@nus.edu.sg [Centre for Nanofibers and Nanotechnology, NUSNNI, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Gandhimathi, C. [Centre for Nanofibers and Nanotechnology, NUSNNI, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Ponpandian, N.; Mangalaraj, D. [Department of Nanoscience and Technology, School of Physical Sciences, Bharathiar University, Coimbatore 641046 (India); Ramakrishna, S. [Centre for Nanofibers and Nanotechnology, NUSNNI, Faculty of Engineering, National University of Singapore, 117576 (Singapore)

    2014-11-01

    Nanofibrous structure developed by electrospinning technology provides attractive extracellular matrix conditions for the anchorage, migration and differentiation of stem cells, including those responsible for regenerative medicine. Recently, biocomposite nanofibers consisting of two or more polymeric blends are electrospun more tidily in order to obtain scaffolds with desired functional and mechanical properties depending on their applications. The study focuses on one such an attempt of using copolymer Poly(L-lactic acid)-co-poly (ε-caprolactone) (PLACL), silk fibroin (SF) and Aloe Vera (AV) for fabricating biocomposite nanofibrous scaffolds for cardiac tissue engineering. SEM micrographs of fabricated electrospun PLACL, PLACL/SF and PLACL/SF/AV nanofibrous scaffolds are porous, beadless, uniform nanofibers with interconnected pores and obtained fibre diameter in the range of 459 ± 22 nm, 202 ± 12 nm and 188 ± 16 nm respectively. PLACL, PLACL/SF and PLACL/SF/AV electrospun mats obtained at room temperature with an elastic modulus of 14.1 ± 0.7, 9.96 ± 2.5 and 7.0 ± 0.9 MPa respectively. PLACL/SF/AV nanofibers have more desirable properties to act as flexible cell supporting scaffolds compared to PLACL for the repair of myocardial infarction (MI). The PLACL/SF and PLACL/SF/AV nanofibers had a contact angle of 51 ± 12° compared to that of 133 ± 15° of PLACL alone. Cardiac cell proliferation was increased by 21% in PLACL/SF/AV nanofibers compared to PLACL by day 6 and further increased to 42% by day 9. Confocal analysis for cardiac expression proteins myosin and connexin 43 was observed better by day 9 compared to all other nanofibrous scaffolds. The results proved that the fabricated PLACL/SF/AV nanofibrous scaffolds have good potentiality for the regeneration of infarcted myocardium in cardiac tissue engineering. - Highlights: • Fabricated nanofibrous scaffolds are porous, beadless and uniform structures. • PLACL/SF/AV nanofibers improve the

  14. Formation and dynamics of supported phospholipid membranes on a periodic nanotextured substrate

    Energy Technology Data Exchange (ETDEWEB)

    Werner, James H [Los Alamos National Laboratory; Montano, Gabriel M [Los Alamos National Laboratory; Shreve, Andrew P [Los Alamos National Laboratory

    2008-01-01

    We have studied and modeled the morphology and dynamics of planar lipid bilayer assemblies supported on a textured silicon substrate that contains nano-structured features perpendicular to the plane of observation. Using a combination of characterization methods, including atomic force microscopy and quantitative fluorescence microscopy, we have discovered the bilayer assemblies are conformal to the underlying nanostructured substrate. As far as the dynamics are concnerned, the lipids freely diffuse in and out of the plane of observation while supported by the nanotextured material. In a microscopic sense, diffusion is isotropic along the patterned substrate. Macroscopically, when observed over length scales exceeding the dimensions of the nano-structured features, the diffusion appears anisotropic. The observed macroscopic anisotropy is well simulated using models of diffusion on the nanostructured surface that assume the lipids diffuse homogeneously and isotropically on the supporting nanotextured substrate.

  15. Thin Film Nanofibrous Composite Membrane for Dead-End Seawater Desalination

    Directory of Open Access Journals (Sweden)

    Baturalp Yalcinkaya

    2016-01-01

    Full Text Available The aim of the study was to prepare a thin film nanofibrous composite membrane utilized for nanofiltration technologies. The composite membrane consists of a three-layer system including a nonwoven part as the supporting material, a nanofibrous scaffold as the porous surface, and an active layer. The nonwoven part and the nanofibrous scaffold were laminated together to improve the mechanical properties of the complete membrane. Active layer formations were done successfully via interfacial polymerization. A filtration test was carried out using solutions of MgSO4, NaCl, Na2SO4, CaCl2, and real seawater using the dead-end filtration method. The results indicated that the piperazine-based membrane exhibited higher rejection of divalent salt ions (>98% with high flux. In addition, the m-phenylenediamine-based membrane exhibited higher rejection of divalent and monovalent salt ions (>98% divalent and >96% monovalent with reasonable flux. The desalination of real seawater results showed that thin film nanofibrous composite membranes were able to retain 98% of salt ions from highly saline seawater without showing any fouling. The electrospun nanofibrous materials proved to be an alternative functional supporting material instead of the polymeric phase-inverted support layer in liquid filtration.

  16. Nanofibrous nonmulberry silk/PVA scaffold for osteoinduction and osseointegration.

    Science.gov (United States)

    Bhattacharjee, Promita; Kundu, Banani; Naskar, Deboki; Maiti, Tapas K; Bhattacharya, Debasis; Kundu, Subhas C

    2015-05-01

    Poly-vinyl alcohol and nonmulberry tasar silk fibroin of Antheraea mylitta are blended to fabricate nanofibrous scaffolds for bone regeneration. Nanofibrous matrices are prepared by electrospinning the equal volume ratio blends of silk fibroin (2 and 4 wt%) with poly-vinyl alcohol solution (10 wt%) and designated as 2SF/PVA and 4SF/PVA, respectively with average nanofiber diameters of 177 ± 13 nm (2SF/PVA) and 193 ± 17 nm (4SF/PVA). Fourier transform infrared spectroscopy confirms retention of the secondary structure of fibroin in blends indicating the structural stability of neo-matrix. Both thermal stability and contact angle of the blends decrease with increasing fibroin percentage. Conversely, fibroin imparts mechanical stability to the blends; greater tensile strength is observed with increasing fibroin concentration. Blended scaffolds are biodegradable and support well the neo-bone matrix synthesis by human osteoblast like cells. The findings indicate the potentiality of nanofibrous scaffolds of nonmulberry fibroin as bone scaffolding material.

  17. Electrospun Nanofibres Containing Antimicrobial Plant Extracts

    Science.gov (United States)

    Zhang, Wanwei; Ronca, Sara; Mele, Elisa

    2017-01-01

    Over the last 10 years great research interest has been directed toward nanofibrous architectures produced by electrospinning bioactive plant extracts. The resulting structures possess antimicrobial, anti-inflammatory, and anti-oxidant activity, which are attractive for biomedical applications and food industry. This review describes the diverse approaches that have been developed to produce electrospun nanofibres that are able to deliver naturally-derived chemical compounds in a controlled way and to prevent their degradation. The efficacy of those composite nanofibres as wound dressings, scaffolds for tissue engineering, and active food packaging systems will be discussed. PMID:28336874

  18. High-flux Thin-film Nanofibrous Composite Ultrafiltration Membranes Containing Cellulose Barrier Layer

    Energy Technology Data Exchange (ETDEWEB)

    Ma, H.; Yoon, K; Rong, L; Mao, Y; Mo, Z; Fang, D; Hollander, Z; Gaiteri, J; Hsiao , B; Chu, B

    2010-01-01

    A novel class of thin-film nanofibrous composite (TFNC) membrane consisting of a cellulose barrier layer, a nanofibrous mid-layer scaffold, and a melt-blown non-woven substrate was successfully fabricated and tested as an ultrafiltration (UF) filter to separate an emulsified oil and water mixture, a model bilge water for on-board ship bilge water purification. Two ionic liquids: 1-butyl-3-methylimidazolium chloride and 1-ethyl-3-methylimidazolium acetate, were chosen as the solvent to dissolve cellulose under mild conditions. The regenerated cellulose barrier layer exhibited less crystallinity (determined by wide-angle X-ray diffraction, WAXD) than the original cotton linter pulps, but good thermal stability (determined by thermal gravimetric analysis, TGA). The morphology, water permeation, and mechanical stability of the chosen TFNCmembranes were thoroughly investigated. The results indicated that the polyacrylonitrile (PAN) nanofibrous scaffold was partially imbedded in the cellulose barrier layer, which enhanced the mechanical strength of the top barrier layer. The permeation flux of the cellulose-based TFNCmembrane was significantly higher (e.g. 10x) than comparable commercial UFmembranes (PAN10 and PAN400, Sepro) with similar rejection ratios for separation of oil/water emulsions. The molecular weight cut-off (MWCO) of TFNC membranes with cellulose barrier layer was evaluated using dextran feed solutions. The rejection was found to be higher than 90% with a dextran molecular weight of 2000 KDa, implying that the nominal pore size of the membrane was less than 50 nm. High permeation flux was also observed in the filtration of an emulsified oil/water mixture as well as of a sodium alginate aqueous solution, while high rejection ratio (above 99.5%) was maintained after prolonged operation. A variation of the barrier layer thickness could dramatically affect the permeation flux and the rejection ratio of the TFNCmembranes, while different sources of cellulose

  19. Synthesis of polyester urethane urea and fabrication of elastomeric nanofibrous scaffolds for myocardial regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Jamadi, Elham Sadat; Ghasemi-Mobarakeh, Laleh [Department of Textile engineering, Isfahan university of technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Morshed, Mohammad, E-mail: morshed@cc.iut.ac.ir [Department of Textile engineering, Isfahan university of technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Sadeghi, Morteza [Department of Chemical Engineering, Isfahan university of technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Prabhakaran, Molamma P., E-mail: nanotechmpp@gmail.com [Department of Mechanical Engineering, Faculty of Engineering, 2 Engineering Drive 3, National University of Singapore, Singapore 117576 (Singapore); Ramakrishna, Seeram [Department of Mechanical Engineering, Faculty of Engineering, 2 Engineering Drive 3, National University of Singapore, Singapore 117576 (Singapore)

    2016-06-01

    Fabrication of bioactive scaffolds is one of the most promising strategies to reconstruct the infarcted myocardium. In this study, we synthesized polyester urethane urea (PEUU), further blended it with gelatin and fabricated PEUU/G nanofibrous scaffolds. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), differential scanning calorimetry (DSC) and X-ray diffraction were used for the characterization of the synthesized PEUU and properties of nanofibrous scaffolds were evaluated using scanning electron microscopy (SEM), ATR-FTIR, contact angle measurement, biodegradation test, tensile strength analysis and dynamic mechanical analysis (DMA). In vitro biocompatibility studies were performed using cardiomyocytes. DMA analysis showed that the scaffolds could be reshaped with cyclic deformations and might remain stable in the frequencies of the physiological activity of the heart. On the whole, our study suggests that aligned PEUU/G 70:30 nanofibrous scaffolds meet the required specifications for cardiac tissue engineering and could be used as a promising construct for myocardial regeneration. - Highlights: • PEUU was synthesized to fabricate elastomeric scaffolds for myocardial regeneration. • FTIR, DSC and XRD analysis showed that polymer synthesis was well. • PEUU/gelatin nanofibrous scaffolds could be reshaped with cyclic deformations of the heart. • Gelatin in structure of PEUU nanofibers improved proliferation of cardiomyocytes. • Aligned PEUU/gelatin 70:30 nanofibrous scaffold support the alignment of cardiomyocytes.

  20. Synthesis of three-dimensional calcium carbonate nanofibrous structure from eggshell using femtosecond laser ablation

    Directory of Open Access Journals (Sweden)

    Venkatakrishnan Krishnan

    2011-01-01

    Full Text Available Abstract Background Natural biomaterials from bone-like minerals derived from avian eggshells have been considered as promising bone substitutes owing to their biodegradability, abundance, and lower price in comparison with synthetic biomaterials. However, cell adhesion to bulk biomaterials is poor and surface modifications are required to improve biomaterial-cell interaction. Three-dimensional (3D nanostructures are preferred to act as growth support platforms for bone and stem cells. Although there have been several studies on generating nanoparticles from eggshells, no research has been reported on synthesizing 3D nanofibrous structures. Results In this study, we propose a novel technique to synthesize 3D calcium carbonate interwoven nanofibrous platforms from eggshells using high repetition femtosecond laser irradiation. The eggshell waste is value engineered to calcium carbonate nanofibrous layer in a single step under ambient conditions. Our striking results demonstrate that by controlling the laser pulse repetition, nanostructures with different nanofiber density can be achieved. This approach presents an important step towards synthesizing 3D interwoven nanofibrous platforms from natural biomaterials. Conclusion The synthesized 3D nanofibrous structures can promote biomaterial interfacial properties to improve cell-platform surface interaction and develop new functional biomaterials for a variety of biomedical applications.

  1. Interaction of laser-cooled 87Rb atoms with higher order modes of an optical nanofibre

    Science.gov (United States)

    Kumar, Ravi; Gokhroo, Vandna; Deasy, Kieran; Maimaiti, Aili; Frawley, Mary C.; Phelan, Ciarán; Chormaic, Síle Nic

    2015-01-01

    Optical nanofibres are used to confine light to sub-wavelength regions and are very promising tools for the development of optical fibre-based quantum networks using cold, neutral atoms. To date, experimental studies on atoms near nanofibres have focussed on fundamental fibre mode interactions. In this work, we demonstrate the integration of a few-mode optical nanofibre into a magneto-optical trap for 87Rb atoms. The nanofibre, with a waist diameter of ∼700 nm, supports both the fundamental and first group of higher order modes (HOMs) and is used for atomic fluorescence and absorption studies. In general, light propagating in higher order fibre modes has a greater evanescent field extension around the waist in comparison with the fundamental mode. By exploiting this behaviour, we demonstrate that the detected signal of fluorescent photons emitted from a cloud of cold atoms centred at the nanofibre waist is larger if HOMs are also included. In particular, the signal from HOMs appears to be about six times larger than that obtained for the fundamental mode. Absorption of on-resonance, HOM probe light by the laser-cooled atoms is also observed. These advances should facilitate the realization of atom trapping schemes based on HOM interference.

  2. General Deposition of Metal-Organic Frameworks on Highly Adaptive Organic-Inorganic Hybrid Electrospun Fibrous Substrates.

    Science.gov (United States)

    Liu, Chang; Wu, Yi-Nan; Morlay, Catherine; Gu, Yifan; Gebremariam, Binyam; Yuan, Xiao; Li, Fengting

    2016-02-01

    Electrospun nanofibrous mats are ideal substrates for metal-organic frameworks (MOFs) crystal deposition because of their specific structural parameters and chemical tenability. In this work, we utilized organic-inorganic hybrid electrospun fibrous mats as support material to study the deposition of various MOF particles. HKUST-1 and MIL-53(Al) were produced through solvothermal method, while ZIF-8 and MIL-88B(Fe) were prepared using microwave-induced heating method. The synthesis procedure for both methods were simple and effective because the hybrid nanofibrous mats showed considerable affinity to MOF particles and could be used without additional modifications. The obtained MOF composites exhibited effective incorporation between MOF particles and the porous substrates. MIL-53(Al) composite was applied as fibrous sorbent and showed enhanced adsorption capacity and removal rate, as well as easier operation, compared with thepowdered sample. Moreover, MIL-53(Al) composite was easier to be regenerated compared with powder form.

  3. Electrical properties of polyaniline nanofibre synthesized with biocatalyst

    Science.gov (United States)

    Kim, Byoung-Kye; Kim, Yong Hwan; Won, Keehoon; Chang, Hyunju; Choi, Youngmin; Kong, Ki-jeong; Rhyu, Beoyong Whan; Kim, Ju-Jin; Lee, Jeong-O.

    2005-08-01

    Polyaniline (PANI) nanofibres were synthesized using a biocatalyst (recombinant Coprinus cinereus peroxidase) instead of toxic chemical oxidants. Relatively uniform nanofibres with 50-100 nm diameter were easily obtained with this method, and the doping state of the PANI nanofibre could be controlled either with 1N camphorsulfonic acid (CSA) or with 30% NH4OH. Doped (or dedoped) PANI nanofibres were deposited on pre-patterned Au electrodes for electrical characterization. Completely dedoped PANI behaves as an insulator, while a larger current, by more than four orders of magnitude, was observed from doped PANI nanofibres. A weak p-type gate effect was observed for PANI nanofibre devices as well. As one could expect from the easy doping nature of PANI, PANI nanofibre devices show high sensitivity toward dedoping (NH3) gases, thereby demonstrating the possibility of using enzyme-synthesized PANI nanofibre devices as sensitive chemical sensors.

  4. Novel antibacterial nanofibrous PLLA scaffolds.

    Science.gov (United States)

    Feng, Kai; Sun, Hongli; Bradley, Mark A; Dupler, Ellen J; Giannobile, William V; Ma, Peter X

    2010-09-15

    In order to achieve high local bioactivity and low systemic side effects of antibiotics in the treatment of dental, periodontal and bone infections, a localized and temporally controlled delivery system is crucial. In this study, a three-dimensional (3-D) porous tissue engineering scaffold was developed with the ability to release antibiotics in a controlled fashion for long-term inhibition of bacterial growth. The highly soluble antibiotic drug, doxycycline (DOXY), was successfully incorporated into PLGA nanospheres using a modified water-in-oil-in-oil (w/o/o) emulsion method. The PLGA nanospheres (NS) were then incorporated into prefabricated nanofibrous PLLA scaffolds with a well interconnected macro-porous structure. The release kinetics of DOXY from four different PLGA NS formulations on a PLLA scaffold was investigated. DOXY could be released from the NS-scaffolds in a locally and temporally controlled manner. The DOXY release is controlled by DOXY diffusion out of the NS and is strongly dependent upon the physical and chemical properties of the PLGA. While PLGA50-6.5K, PLGA50-64K, and PLGA75-113K NS-scaffolds discharge DOXY rapidly with a high initial burst release, PLGA85-142K NS-scaffold can extend the release of DOXY to longer than 6weeks with a low initial burst release. Compared to NS alone, the NS incorporated on a 3-D scaffold had significantly reduced the initial burst release. In vitro antibacterial tests of PLGA85 NS-scaffold demonstrated its ability to inhibit common bacterial growth (S. aureus and E. coli) for a prolonged duration. The successful incorporation of DOXY onto 3-D scaffolds and its controlled release from scaffolds extends the usage of nano-fibrous scaffolds from the delivery of large molecules such as growth factors to the delivery of small hydrophilic drugs, allowing for a broader application and a more complex tissue engineering strategy. 2010 Elsevier B.V. All rights reserved.

  5. Bifunctional lanthanum phosphate substrates as novel adsorbents and biocatalyst supports for perchlorate removal

    Energy Technology Data Exchange (ETDEWEB)

    Sankar, Sasidharan [Materials Science and Technology Division (India); Prajeesh, Gangadharan Puthiya Veetil; Anupama, Vijaya Nadaraja [Process Engineering and Environmental Technology Division, CSIR – National Institute for Interdisciplinary Science and Technology, Industrial Estate P.O., Thiruvananthapuram 695019 (India); Krishnakumar, Bhaskaran [Process Engineering and Environmental Technology Division, CSIR – National Institute for Interdisciplinary Science and Technology, Industrial Estate P.O., Thiruvananthapuram 695019 (India); Academy of Scientific and Industrial Research (AcSIR) (India); Hareesh, Padinhattayil [Materials Science and Technology Division (India); Nair, Balagopal N. [R and D Centre, Noritake Co. Ltd., Aichi (Japan); Warrier, Krishna Gopakumar [Materials Science and Technology Division (India); Academy of Scientific and Industrial Research (AcSIR) (India); Hareesh, Unnikrishnan Nair Saraswathy, E-mail: hareesh@niist.res.in [Materials Science and Technology Division (India); Academy of Scientific and Industrial Research (AcSIR) (India)

    2014-06-30

    Graphical abstract: Porous lanthanum phosphate substrates, obtained by an environmentally benign thermal gelation process, performed the role of dual functional sorbent facilitating perchlorate adsorption and bioremediation through the growth of perchlorate reducing microbial colonies. - Highlights: • Lanthanum phosphate monoliths as efficient perchlorate adsorbents. • And also as substrates for biofilm (perchlorate reducing bacteria) growth. • Environmentally benign thermal gelation process for substrate fabrication. • 98% adsorption efficiency for perchlorate concentrations up to 100 μg/L. • The regenerated monoliths show nearly 100% reusability. - Abstract: Porous lanthanum phosphate substrates, obtained by an environmentally benign colloidal forming process employing methyl cellulose, are reported here as excellent adsorbents of perchlorate with >98% efficiency and with 100% reusability. Additionally, the effectiveness of such substrates as biocatalyst supports that facilitate biofilm formation of perchlorate reducing microbes (Serratia marcescens NIIST 5) is also demonstrated for the first time. The adsorption of perchlorate ions is attributed to the pore structure of lanthanum phosphate substrate and the microbial attachment is primarily ascribed to its intrinsic hydrophobic property. Lanthanum phosphate thus emerges as a dual functional material that possesses an integrated adsorption/bioremediation property for the effective removal of ClO{sub 4}{sup −} which is an increasingly important environmental contaminant.

  6. Elastic hydrogel substrate supports robust expansion of murine myoblasts and enhances their engraftment

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Ke, E-mail: dk1118@yeah.net [Department of Pediatric Surgery, Sichuan Academy of Medical Sciences & Sichuan Provincial People’s Hospital, Chengdu 610072 (China); Yang, Zhong [Department of Clinical Hematology, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Xu, Jian-zhong, E-mail: xjzspine@163.com [Department of Orthopaedics, Southwest Hospital, Third Military Medical University, Chongqing 400038 (China); Liu, Wen-ying; Zeng, Qiang; Hou, Fang [Department of Pediatric Surgery, Sichuan Academy of Medical Sciences & Sichuan Provincial People’s Hospital, Chengdu 610072 (China); Lin, Sen [Department of Anatomy and Histology & Embryology, Chengdu Medical College, Chengdu 610500 (China)

    2015-09-10

    The application of satellite cell-derived myoblasts in regenerative medicine has been restricted by the rapid loss of stemness during in vitro cell expansion using traditional culture systems. However, studies published in the past decade have highlighted the influence of substrate elasticity on stem cell fate and revealed that culture on a soft hydrogel substrate can promote self-renewal and prolong the regenerative potential of muscle stem cells. Whether hydrogel substrates have similar effects after long-term robust expansion remains to be determined. Herein we prepared an elastic chitosan/beta-glycerophosphate/collagen hydrogel mimicking the soft microenvironment of muscle tissues for use as the substrate for satellite cell culture and investigated its influence on long-term cell expansion. After 20 passages in culture, satellite cell-derived myoblasts cultured on our hydrogel substrate exhibited significant improvements in proliferation capability, cell viability, colony forming frequency, and potential for myogenic differentiation compared to those cultured on a routine rigid culture surface. Immunochemical staining and western blot analysis both confirmed that myoblasts cultured on the hydrogel substrate expressed higher levels of several differentiation-related markers, including Pax7, Pax3, and SSEA-1, and a lower level of MyoD compared to myoblasts cultured on rigid culture plates (all p<0.05). After transplantation into the tibialis anterior of nude mice, myoblasts that had been cultured on the hydrogel substrate demonstrated a significantly greater engraftment efficacy than those cultured on the traditional surface. Collectively, these results indicate that the elastic hydrogel substrate supported robust expansion of murine myoblasts and enhanced their engraftment in vivo. - Highlights: • An elastic hydrogel was designed to mimic the pliable muscle tissue microenvironment. • Myoblasts retained their stemness in long-term culture on the elastic

  7. Self-supported ceramic substrates with directional porosity by mold freeze casting

    DEFF Research Database (Denmark)

    Gurauskis, Jonas; Graves, Christopher R.; Moreno, R.

    2016-01-01

    Manufacture of thin-film ceramic substrates with high permeability and robustness is of high technological interest. In this work thin (green state thickness ∼500 μm) porous yttria-stabilized zirconia self-supported substrates were fabricated by pouring stable colloidal aqueous suspensions...... in a mold and applying directional freeze casting. Use of optimized suspension, cryoprotector additive and mold proved to deliver defect free ceramic films with high dimensional control. Microstructure analysis demonstrated the formation of desirable aligned porosity at macro-structural scale and resulted...

  8. High-temperature behavior of supported graphene: Electron-phonon coupling and substrate-induced doping

    DEFF Research Database (Denmark)

    Ulstrup, Søren; Bianchi, Marco; Guan, Dandan

    2012-01-01

    The temperature-dependent electronic structure and electron-phonon coupling of weakly doped supported graphene is studied by angle-resolved photoemission spectroscopy and ab initio molecular dynamics simulations. The electron-phonon coupling is found to be extremely weak, reaching the lowest value...... ever reported for any material. However, the temperature-dependent dynamic interaction with the substrate leads to a complex and dramatic change in the carrier density and type in graphene. These changes in the electronic structure are mainly caused by fluctuations in the graphene-substrate distance....

  9. Dielectric properties of electrospun titanium compound/polymer composite nanofibres

    Science.gov (United States)

    Li, Meng-Meng; Long, Yun-Ze; Tan, Jin-Shan; Yin, Hong-Xing; Sui, Wan-Mei; Zhang, Zhi-Ming

    2010-02-01

    Poly(vinylpyrrolidone)/tetrabutyl titanate (PVP/ [CH3(CH2)3O]4Ti) composite nanofibres are prepared by electrospinning. After calcining parts of composite nanofibres in air at 700 °C, petal-like TiO2 nanostructures are obtained. The characterizations of composite nanofibres and TiO2 nanostructures are carried out by a scanning electron microscope, an x-ray diffractometer, and an infrared spectrometer. Electrospun nanofibres are pressed into pellets under different pressures in order to explore their dielectric properties. It is found that the dielectric constants decrease with frequency increasing. The dielectric constant of the composite nanofibre pellet increases whereas its dielectric loss tangent decreases due to the doped titanium ions compared with those of pure PVP nanofibre pellets. In addition, it is observed that the dielectric constant of the composite nanofibre pellet decreases with the increase of the pressure applied in pelletization.

  10. Functional Electrospun Nanofibrous Scaffolds for Biomedical Applications

    Science.gov (United States)

    Liang, Dehai; Hsiao, Benjamin S.; Chu, Benjamin

    2009-01-01

    Functional nanofibrous scaffolds produced by electrospinning have great potential in many biomedical applications, such as tissue engineering, wound dressing, enzyme immobilization and drug (gene) delivery. For a specific successful application, the chemical, physical and biological properties of electrospun scaffolds should be adjusted to match the environment by using a combination of multi-component compositions and fabrication techniques where electrospinning has often become a pivotal tool. The property of the nanofibrous scaffold can be further improved with innovative development in electrospinning processes, such as two-component electrospinning and in-situ mixing electrospinning. Post modifications of electrospun membranes also provide effective means to render the electrospun scaffolds with controlled anisotropy and porosity. In this review, we review the materials, techniques and post modification methods to functionalize electrospun nanofibrous scaffolds suitable for biomedical applications. PMID:17884240

  11. Novel transparent and flexible nanocomposite film prepared from chrysotile nanofibres

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Kun, E-mail: kliu@csu.edu.cn [School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 (China); Zhu, Binnan; Feng, Qiming [School of Minerals Processing and Bioengineering, Central South University, Changsha 410083 (China); Duan, Tao [Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, CAEP, Mianyang 621010 (China)

    2013-10-01

    In the present study, chrysotile nanofibres, obtained from physicochemical dispersion of natural chrysotile, were used to prepare nanofibre sheets by vacuum filtration. As-prepared sheets were then impregnated by UV-curable resin and cured by ultraviolet light to fabricate the flexible and transparent nanocomposite films. Observed from SEM, the transparent films showed a smooth surface and a typical sandwich structure in cross section, viz. nanofibre sheet filled with resin was sandwiched by two layers of resin. XRD patterns indicated the amorphous nature of cured resin and characteristic crystallographic structure of chrysotile in nanocomposite films. Though the nanofibre sheets were white in colour, and nanofibre contents in nanocomposites were as much as 43.4 wt%, the nanocomposite films displayed an excellent optical transparency with about 85% light transmittance in the visible light range. Tensile tests showed that the addition of nanofibres resulted in a great improvement in mechanical strength of the nanocomposite films; with the increase of nanofibre contents, the modulus and tensile strength of nanocomposite films increased gradually. - Graphical abstract: Photos show the experimental phenomenon. The white nanofibre sheets can be written or printed like paper, and it's very interested that the handwriting is clearly visible from the front and back of the transparent films prepared from nanofibre sheets by vacuum impregnation and UV curing. This phenomenon can be attributed to the increase of transparency of film, which results from the replacement of air interstices in nanofibre sheet by resin with higher refractive index. Visible light can pass easily through the transparent film without obvious loss, but can be apparently adsorbed and scattered by ink particles that adhered to nanofibres and embedded in resin. - Highlights: • A flexible and transparent film is prepared from chrysotile nanofibres. • The nanofibre sheet is sandwiched by two

  12. Plant Growth Experiments in Zeoponic Substrates: Applications for Advanced Life Support Systems

    Science.gov (United States)

    Ming, Douglas W.; Gruener, J. E.; Henderson, K. E.; Steinberg, S. L.; Barta, D. J.; Galindo, C.; Henninger, D. L.

    2001-01-01

    A zeoponic plant-growth system is defined as the cultivation of plants in artificial soils, which have zeolites as a major component (Allen and Ming, 1995). Zeolites are crystalline, hydrated aluminosilicate minerals that have the ability to exchange constituent cations without major change of the mineral structure. Recently, zeoponic systems developed at the National Aeronautics and Space Administration (NASA) slowly release some (Allen et at., 1995) or all of the essential plant-growth nutrients (Ming et at., 1995). These systems have NH4- and K-exchanged clinoptilolite (a natural zeolite) and either natural or synthetic apatite (a calcium phosphate mineral). For the natural apatite system, Ca and P were made available to the plant by the dissolution of apatite. Potassium and NH4-N were made available by ion-exchange reactions involving Ca(2+) from apatite dissolution and K(+) and NH4(+) on zeolitic exchange sites. In addition to NH4-N, K, Ca, and P, the synthetic apatite system also supplied Mg, S, and other micronutrients during dissolution (Figure 1). The overall objective of this research task is to develop zeoponic substrates wherein all plant growth nutrients are supplied by the plant growth medium for several growth seasons with only the addition of water. The substrate is being developed for plant growth in Advanced Life Support (ALS) testbeds (i.e., BioPLEX) and microgravity plant growth experiments. Zeoponic substrates have been used for plant growth experiments on two Space Shuttle flight experiments (STS-60; STS-63; Morrow et aI., 1995). These substrates may be ideally suited for plant growth experiments on the International Space Station and applications in ALS testbeds. However, there are several issues that need to be resolved before zeoponics will be the choice substrate for plant growth experiments in space. The objective of this paper is to provide an overview on recent research directed toward the refinement of zeoponic plant growth substrates.

  13. A map of competing buckling-driven failure modes of substrate-supported thin brittle films

    Energy Technology Data Exchange (ETDEWEB)

    Jia, Zheng [Department of Mechanical Engineering and Maryland NanoCenter, University of Maryland, College Park, MD 20742 (United States); Peng, Cheng [Department of Mechanical Engineering and Materials Science, Rice University, Houston, TX 77005 (United States); Lou, Jun, E-mail: jlou@rice.edu [Department of Mechanical Engineering and Materials Science, Rice University, Houston, TX 77005 (United States); Li, Teng, E-mail: lit@umd.edu [Department of Mechanical Engineering and Maryland NanoCenter, University of Maryland, College Park, MD 20742 (United States)

    2012-08-31

    Our in situ experiments of polyimide-supported thin indium tin oxide (ITO) films reveal buckling-driven film cracking in some samples and buckling-driven interfacial delamination in other samples. Although studies of individual buckling-driven failure mode exist, it still remains unclear what governs the competition between these two different failure modes in a given film/substrate structure. Through theoretical analysis and numerical simulations, we delineate a map of competing buckling-driven failure modes of substrate-supported thin brittle films in the parameter space of interfacial adhesion and interfacial imperfection size. Such a map can offer insight on the mechanical durability of functional thin films. For example, interestingly, we show that strongly bonded thin brittle films are more prone to buckling-driven cracking, a more detrimental failure mode for thin brittle ITO transparent conductors widely used in displays and flexible electronics. - Highlights: Black-Right-Pointing-Pointer Map of buckling-driven failure modes of thin brittle films on substrates. Black-Right-Pointing-Pointer We study key parameters that govern buckling-driven failure modes. Black-Right-Pointing-Pointer The map offers insights on optimal design of functional thin films.

  14. Width and Crystal Orientation Dependent Band Gap Renormalization in Substrate-Supported Graphene Nanoribbons.

    Science.gov (United States)

    Kharche, Neerav; Meunier, Vincent

    2016-04-21

    The excitation energy levels of two-dimensional (2D) materials and their one-dimensional (1D) nanostructures, such as graphene nanoribbons (GNRs), are strongly affected by the presence of a substrate due to the long-range screening effects. We develop a first-principles approach combining density functional theory (DFT), the GW approximation, and a semiclassical image-charge model to compute the electronic band gaps in planar 1D systems in weak interaction with the surrounding environment. Application of our method to the specific case of GNRs yields good agreement with the range of available experimental data and shows that the band gap of substrate-supported GNRs are reduced by several tenths of an electronvolt compared to their isolated counterparts, with a width and orientation-dependent renormalization. Our results indicate that the band gaps in GNRs can be tuned by controlling screening at the interface by changing the surrounding dielectric materials.

  15. Metal–polyaniline nanofibre composite for supercapacitor applications

    Indian Academy of Sciences (India)

    S H Kazemi; M A Kiani; R Mohamadi; L Eskandarian

    2014-08-01

    The aim of the present work is to increase the electrical conductivity and specific capacitance of the polyaniline (PANi) nanofibres by introducing the metallic nanostructures. Herein, metal nanoparticleincorporated PANi nanofibres were prepared from interfacially synthesized PANi nanofibres as seeds. In the main step of aniline polymerization, the seeds were employed to produce a large amount of PANi nanofibres in the next steps. Also, metal–PANi nanofibres were chemically prepared by adding inorganic salts (nickel and copper salts) which incorporated PANi nanofibres via the self-assembly process. Increased conductivity and good electrochemical behaviour were observed for these metal–PANi nanofibres at room temperature compared with the single PANi nanofibres, which was previously reported. SEM, FT–IR and UV–Vis techniques were applied for characterization of the products. Finally, the potential application of the composites to use as electrode materials for supercapacitor was examined. Elevated specific capacitance in addition to good cycle stability was observed for the metal–PANi nanofibres. Also, electrochemical impedance spectroscopy and charge/discharge experiments show that these metal–PANi nanofibres possess the high conductivity and low charge transfer resistance, which make them suitable candidates for high-performance supercapacitors.

  16. Carboxymethyl cellulose enables silk fibroin nanofibrous scaffold with enhanced biomimetic potential for bone tissue engineering application.

    Science.gov (United States)

    Singh, B N; Panda, N N; Mund, R; Pramanik, K

    2016-10-20

    Novel silk fibroin (SF) and carboxymethyl cellulose (CMC) composite nanofibrous scaffold (SFC) were developed to investigate their ability to nucleate bioactive nanosized calcium phosphate (Ca/P) by biomineralization for bone tissue engineering application. The composite nanofibrous scaffold was prepared by free liquid surface electrospinning method. The developed composite nanofibrous scaffold was observed to control the size of Ca/P particle (≤100nm) as well as uniform nucleation of Ca/P over the surface. The obtained nanofibrous scaffolds were fully characterized for their functional, structural and mechanical property. The XRD and EDX analysis depicted the development of apatite like crystals over SFC scaffolds of nanospherical in morphology and distributed uniformly throughout the surface of scaffold. Additionally, hydrophilicity as a measure of contact angle and water uptake capacity is higher than pure SF scaffold representing the superior cell supporting property of the SF/CMC scaffold. The effect of biomimetic Ca/P on osteogenic differentiation of umbilical cord blood derived human mesenchymal stem cells (hMSCs) studied in early and late stage of differentiation shows the improved osteoblastic differentiation capability as compared to pure silk fibroin. The obtained result confirms the positive correlation of alkaline phosphatase activity, alizarin staining and expression of runt-related transcription factor 2, osteocalcin and type1 collagen representing the biomimetic property of the scaffolds. Thus, the developed composite has been demonstrated to be a potential scaffold for bone tissue engineering application.

  17. Substrate inhibition in the heterogeneous catalyzed aldol condensation: A mechanistic study of supported organocatalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kandel, Kapil; Althaus, Stacey M.; Peeraphatdit, Chorthip; Kobayashi, Takeshi; Trewyn, Brian G.; Pruski, Marek; Slowing, Igor I.

    2012-05-23

    In this study, we demonstrate how materials science can be combined with the established methods of organic chemistry to find mechanistic bottlenecks and redesign heterogeneous catalysts for improved performance. By using solid-state NMR, infrared spectroscopy, surface and kinetic analysis, we prove the existence of a substrate inhibition in the aldol condensation catalyzed by heterogeneous amines. We show that modifying the structure of the supported amines according to the proposed mechanism dramatically enhances the activity of the heterogeneous catalyst. We also provide evidence that the reaction benefits significantly from the surface chemistry of the silica support, which plays the role of a co-catalyst, giving activities up to two orders of magnitude larger than those of homogeneous amines. This study confirms that the optimization of a heterogeneous catalyst depends as much on obtaining organic mechanistic information as it does on controlling the structure of the support.

  18. Nanofibrous Resonant Membrane for Acoustic Applications

    Directory of Open Access Journals (Sweden)

    K. Kalinová

    2011-01-01

    Full Text Available Because the absorption of lower-frequency sound is problematic with fibrous material made up of coarser fibers, highly efficient sound absorption materials must be developed. The focus of this paper is on the development of a new material with high acoustic absorption characteristics. For low-frequency absorption, structures based upon the resonance principle of nanofibrous layers are employed in which the resonance of some elements allows acoustic energy to be converted into thermal energy. A nanofibrous membrane was produced by an electrostatic spinning process from an aqueous solution of polyvinyl alcohol and the acoustic characteristics of the material measured. The resonant frequency prediction for the nanofibrous membrane is based on research into its production parameters. The distance between electrodes during the electrostatic spinning process determines the average diameter of the nanofibers, and the outlet velocity of the material determines its area density. The average diameter of nanofibers was measured using the Lucia software package directly from an electron microscope image. The resonant frequency of nanofibrous membranes was determined from the sound absorption coefficient and transmission loss measurement.

  19. Innovations with protein nano-fibres

    NARCIS (Netherlands)

    Linden, van der E.

    2006-01-01

    Proteins in solution can form objects of various shapes. One fascinating possibility is the formation of fibres with a length up to micrometers, but with a thickness of a few nanometers, therefore referring to them as nano-fibres. Many proteins show this behaviour under the appropriate conditions. G

  20. Filling of carbon nanotubes and nanofibres

    Directory of Open Access Journals (Sweden)

    Reece D. Gately

    2015-02-01

    Full Text Available The reliable production of carbon nanotubes and nanofibres is a relatively new development, and due to their unique structure, there has been much interest in filling their hollow interiors. In this review, we provide an overview of the most common approaches for filling these carbon nanostructures. We highlight that filled carbon nanostructures are an emerging material for biomedical applications.

  1. A novel gellan-PVA nanofibrous scaffold for skin tissue regeneration: Fabrication and characterization.

    Science.gov (United States)

    Vashisth, Priya; Nikhil, Kumar; Roy, Partha; Pruthi, Parul A; Singh, Rajesh P; Pruthi, Vikas

    2016-01-20

    In this investigation, we have introduced novel electrospun gellan based nanofibers as a hydrophilic scaffolding material for skin tissue regeneration. These nanofibers were fabricated using a blend mixture of gellan with polyvinyl alcohol (PVA). PVA reduced the repulsive force of resulting solution and lead to formation of uniform fibers with improved nanostructure. Field emission scanning electron microscopy (FESEM) confirmed the average diameter of nanofibers down to 50 nm. The infrared spectra (IR), differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis evaluated the crosslinking, thermal stability and highly crystalline nature of gellan-PVA nanofibers, respectively. Furthermore, the cell culture studies using human dermal fibroblast (3T3L1) cells established that these gellan based nanofibrous scaffold could induce improved cell adhesion and enhanced cell growth than conventionally proposed gellan based hydrogels and dry films. Importantly, the nanofibrous scaffold are biodegradable and could be potentially used as a temporary substrate/or biomedical graft to induce skin tissue regeneration.

  2. Preparation of Aligned Polymer Micro/Nanofibres by Electrospinning

    Institute of Scientific and Technical Information of China (English)

    TAN Jin-Shan; LONG Yun-Ze; LI Meng-Meng

    2008-01-01

    @@ Polymer micro/nanofibres are prepared by typical and modified methods of electrospinning. The morphologies and microstructures of the electrospun micro/nanofibres are characterized by a scanning electron microscope (SEM). The micro/nanofibres prepared by the typical electrospinning are usually collected in the form of non-woven mats lacking of structural orientation. However, by modifying collector(s) of the electrospinning setup, the resulting polymer fibres show aligned structures to some extent. We analyse all the forces that the fibres experienced during electrospinning and find that the electrostatic force originating from the splitting electric field plays a key role in the alignment of the micro/nanofibres.

  3. Preparation of Antibacterial Nanofibre/Nanoparticle Covered Composite Yarns

    Directory of Open Access Journals (Sweden)

    Fatma Yalcinkaya

    2016-01-01

    Full Text Available The antibacterial efficiency of nanofibre composite yarns with an immobilized antibacterial agent was tested. This novel type of nanofibrous composite material combines the good mechanical properties of the core yarn with the high specific surface of the nanofibre shell to gain specific targeted qualities. The main advantages of nanofibre covered composite yarns over the standard planar nanofibre membranes include high tensile strength, a high production rate, and their ability to be processed by standard textile techniques. The presented paper describes a study of the immobilization of an antibacterial agent and its interaction with two types of bacterial colonies. The aim of the study is to assess the applicability of the new composite nanomaterial in antibacterial filtration. During the experimental tests copper(II oxide particles were immobilized in the polyurethane and polyvinyl butyral nanofibre components of a composite yarn. The antibacterial efficiency was evaluated by using both Gram-negative Escherichia coli and Gram-positive Staphylococcus gallinarum bacteria. The results showed that the composite yarn with polyvinyl butyral nanofibres incorporating copper(II oxide nanoparticles exhibited better antibacterial efficiency compared to the yarn containing the polyurethane nanofibres. The nanofibre/nanoparticle covered composite yarns displayed good antibacterial activity against a number of bacteria.

  4. Few Atom Detection and Manipulation Using Optical Nanofibres

    Science.gov (United States)

    Deasy, Kieran; Watkins, Amy; Morrissey, Michael; Schmidt, Regine; Chormaic, Síle Nic

    We study the coupling of spontaneously emitted photons from laser-cooled 85Rb atoms to the guided modes of an optical nanofibre to demonstrate the potential such fibres offer as tools for detecting and manipulating cold atoms, even when the number of atoms is very small. We also demonstrate the integration of an optical nanofibre into an absorption spectroscopy setup, showcasing the ability of the evanescent field around nanofibres to interact with atoms in close proximity to the fibre. In principle, trapping of single atoms in engineered optical potentials on the surface of the fibre should facilitate entanglement between distant atoms mediated via the guided modes of the nanofibre.

  5. Nanostructured optical nanofibres for atom trapping

    CERN Document Server

    Daly, Mark; Phelan, Ciarán; Deasy, Kieran; Chormaic, Síle Nic

    2013-01-01

    We propose an optical dipole trap for cold neutral atoms based on the electric field produced from the evanescent fields in a hollow rectangular slot cut through an optical nanofibre. In particular, we discuss the trap performance in relation to laser-cooled rubidium atoms and show that a far off-resonance, blue-detuned field combined with the attractive surface-atom interaction potential from the dielectric material forms a stable trapping configuration. With the addition of a red-detuned field, we demonstrate how three dimensional confinement of the atoms at a distance of 140 - 200 nm from the fibre surface within the slot can be accomplished. This scheme facilitates optical coupling between the atoms and the nanofibre that could be exploited for quantum communication schemes using ensembles of laser-cooled atoms.

  6. Nanostructured optical nanofibres for atom trapping

    Science.gov (United States)

    Daly, M.; Truong, V. G.; Phelan, C. F.; Deasy, K.; Chormaic, S. Nic

    2014-05-01

    We propose an optical dipole trap for cold, neutral atoms based on the electric field produced from the evanescent fields in a hollow, rectangular slot cut through an optical nanofibre. In particular, we discuss the trap performance in relation to laser-cooled rubidium atoms and show that a far off-resonance, blue-detuned field combined with the attractive surface-atom interaction potential from the dielectric material forms a stable trapping configuration. With the addition of a red-detuned field, we demonstrate how three dimensional confinement of the atoms at a distance of 140-200 nm from the fibre surface within the slot can be accomplished. This scheme facilitates optical coupling between the atoms and the nanofibre that could be exploited for quantum communication schemes using ensembles of laser-cooled atoms.

  7. Microgravity effects on water supply and substrate properties in porous matrix root support systems

    Science.gov (United States)

    Bingham, G. E.; Jones, S. B.; Or, D.; Podolski, I. G.; Levinskikh, M. A.; Sytchov, V. N.; Ivanova, T.; Kostov, P.; Sapunova, S.; Dandolov, I.; Bubenheim, D. B.; Jahns, G.; Campbell, W. F. (Principal Investigator)

    2000-01-01

    The control of water content and water movement in granular substrate-based plant root systems in microgravity is a complex problem. Improper water and oxygen delivery to plant roots has delayed studies of the effects of microgravity on plant development and the use of plants in physical and mental life support systems. Our international effort (USA, Russia and Bulgaria) has upgraded the plant growth facilities on the Mir Orbital Station (OS) and used them to study the full life cycle of plants. The Bulgarian-Russian-developed Svet Space Greenhouse (SG) system was upgraded on the Mir OS in 1996. The US developed Gas Exchange Measurement System (GEMS) greatly extends the range of environmental parameters monitored. The Svet-GEMS complex was used to grow a fully developed wheat crop during 1996. The growth rate and development of these plants compared well with earth grown plants indicating that the root zone water and oxygen stresses that have limited plant development in previous long-duration experiments have been overcome. However, management of the root environment during this experiment involved several significant changes in control settings as the relationship between the water delivery system, water status sensors, and the substrate changed during the growth cycles. c 2001 Published by Elsevier Science Ltd. All rights reserved.

  8. Suppressed superconductivity in substrate-supported β 12 borophene by tensile strain and electron doping

    Science.gov (United States)

    Cheng, Cai; Sun, Jia-Tao; Liu, Hang; Fu, Hui-Xia; Zhang, Jin; Chen, Xiang-Rong; Meng, Sheng

    2017-06-01

    Planar borophene, the truly 2D monolayer boron, has been independently successfully grown on Ag(1 1 1) by two groups (2016 Nat. Chem. 8 563 and 2015 Science 350 1513), which has received widespreading attentions. The superconducting property has not been unambiguously observed, which is unexpected because light element boron should have strong electron-phonon coupling. To resolve this puzzle, we show that the superconducting transition temperature T c of β 12 borophene is effectively suppressed by the substrate-induced tensile strain and electron doping via first principles calculations. The biaxial tensile strain of 2% induced by Ag(1 1 1) significantly reduces T c from 14 K to 2.95 K electron doping of 0.1 e- per boron atom further shrinks T c to 0.09 K. We also predict that the superconducting transition temperature in β 12 can be enhanced to 22.82 K with proper compressive strain (-1%) and 18.97 K with hole doping (0.1 h+ per boron). Further studies indicate that the variation of T c is closely related to the density of states of σ bands near the Fermi surface. Our results help to explain the challenges to experimentally probe superconductivity in substrate-supported borophene.

  9. Preparation and investigation of polylactic acid, calcium carbonate and polyvinylalcohol nanofibrous scaffolds for osteogenic differentiation of mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    A. Doustgani

    2016-04-01

    Full Text Available Objective(s: In this study, the effect of electrospun fiber orientation on proliferation and differentiation of mesenchymal stem cells (MSCs was evaluated. Materials and Methods: Aligned and random nanocomposite nanofibrous scaffolds were electrospun from polylactic acid (PLA, poly (vinyl alcohol (PVA and calcium carbonate nanoparticles (nCaP. The surface morphology of prepared nanofibrous scaffolds with and without cell was examined using scanning electron microscopy. Mechanical properties of electrospun nanofibrous scaffolds were determined with a  universal testing machine. The in vitro properties of fabricated scaffolds was also investigated by the MTT assay and alkaline phosphatase activity (ALP.Results: The average fiber diameter for aligned and random nanofibers were 82 ± 12 nm and 124 ± 25 nm, respectively. The mechanical testing indicated the higher tensile strength and elastic modulus of aligned nanofibers. MTT and ALP results showed that alignment of nanofiber increased the osteogenic differentiation of stem cells.Conclusion: Aligned nanofibrous nanocomposite scaffolds of PLA/nCaP/PVA could be an excellent substrate for MSCs and represents a potential bone-filling material.

  10. Enhanced chondrogenesis of human nasal septum derived progenitors on nanofibrous scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Shafiee, Abbas [Department of Tissue Engineering, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Stem Cell biology and Tissue Engineering Departments, Stem Cell Technology Research Center, Tehran (Iran, Islamic Republic of); Institute of Health and Biomedical Innovation, Queensland University of Technology (QUT), Brisbane, QLD (Australia); Seyedjafari, Ehsan [Department of Biotechnology, College of Science, University of Tehran, Tehran (Iran, Islamic Republic of); Sadat Taherzadeh, Elham [Stem Cell biology and Tissue Engineering Departments, Stem Cell Technology Research Center, Tehran (Iran, Islamic Republic of); Dinarvand, Peyman [Stem Cell biology and Tissue Engineering Departments, Stem Cell Technology Research Center, Tehran (Iran, Islamic Republic of); The Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, Saint Louis, MO (United States); Soleimani, Masoud [Hematology Department, Faculty of Medical Science, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Ai, Jafar, E-mail: jafar_ai@tums.ac.ir [Department of Tissue Engineering, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Brain and Spinal Injury Research Center, Imam Hospital, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of)

    2014-07-01

    Topographical cues can be exploited to regulate stem cell attachment, proliferation, differentiation and function in vitro and in vivo. In this study, we aimed to investigate the influence of different nanofibrous topographies on the chondrogenic differentiation potential of nasal septum derived progenitors (NSP) in vitro. Aligned and randomly oriented Ploy (L-lactide) (PLLA)/Polycaprolactone (PCL) hybrid scaffolds were fabricated via electrospinning. First, scaffolds were fully characterized, and then NSP were seeded on them to study their capacity to support stem cell attachment, proliferation and chondrogenic differentiation. Compared to randomly oriented nanofibers, aligned scaffolds showed a high degree of nanofiber alignment with much better tensile strength properties. Both scaffolds supported NSP adhesion, proliferation and chondrogenic differentiation. Despite the higher rate of cell proliferation on random scaffolds, a better chondrogenic differentiation was observed on aligned nanofibers as deduced from higher expression of chondrogenic markers such as collagen type II and aggrecan on aligned scaffolds. These findings demonstrate that electrospun constructs maintain NSP proliferation and differentiation, and that the aligned nanofibrous scaffolds can significantly enhance chondrogenic differentiation of nasal septum derived progenitors. - Highlights: • Electrospun nanofiber scaffolds with different topographies were fabricated. • Aligned nanofiber scaffolds had better tensile strength properties. • Nasal septum derived progenitors were cultured on nanofibrous scaffolds. • Both topographies support proliferation and chondrogenic differentiation. • Better chondrogenic differentiation was observed on aligned nanofibers.

  11. SOUND ABSORPTION BEHAVIOR OF ELECTROSPUN POLYACRYLONITRILE NANOFIBROUS MEMBRANES

    Institute of Scientific and Technical Information of China (English)

    Hai-fan Xiang; Shuai-xia Tan; Xiao-lan Yu; Yu-hua Long; Xiao-li Zhang; Ning Zhao; Jian Xu

    2011-01-01

    The acoustical damping property of electrospun polyacrylonitrile (PAN) nanofibrous membranes with different thicknesses and porosities was investigated.The sound absorption coefficients were measured using the impedance tube instrument based on ISO10534-2:1998(E).Results indicate that the first resonance absorption frequency of nanofibrous membranes shifts to the lower frequency with the increase of the back cavity or the thickness of membranes.Moreover,the sound absorption performance of the perforated panel can be greatly improved by combination with a thin layer of PAN nanofibrous membrane.Traditional acoustical damping materials (foam,fiber) coated with nanofibrous membranes have better acoustical performance in the low and medium frequency range than that of acoustical materials alone.All of the results demonstrate the PAN nanofibrous membrane is a suitable candidate for noise reduction.

  12. Towards rational design of catalysts supported on a topological insulator substrate

    CERN Document Server

    Xiao, Jianping; Yam, Chi-Yung; Frauenheim, Thomas; Yan, Binghai

    2015-01-01

    Exotic and robust metallic surface states of topological insulators (TIs) have been expected to provide a promising platform for novel surface chemistry and catalysis. However, it is still an unprecedented field how TIs affect the activity of catalysts. In this work, we study the effects of topological surface states (TSSs) on the activity of transition metal clusters (Au, Ag, Cu, Pt, and Pd), which are supported on a TI Bi2Se3 substrate. It was found the adsorption energy of oxygen on the supported catalysts can be always enhanced due to the TSSs. However, it does not necessarily mean an increase of the activity in catalytic oxidation reaction. Rather, the enhanced adsorption behavior in the presence of TSSs exhibits dual effects, determined by the intrinsic reactivity of these catalysts with oxygen. For the Au case, the activity of catalytic oxidation can be improved because the intrinsic binding between Au and O is relatively weak. In contrast, a negative effect is found for the Pt and Pd clusters since th...

  13. A simplified density functional theory method for charged adsorbates on an ultrathin, insulating film supported by a metal substrate

    OpenAIRE

    Scivetti, Ivan; Persson, Mats

    2013-01-01

    A simplified density functional theory (DFT) method for charged adsorbates on an ultrathin, insulating film supported by a metal substrate is developed and presented. This new method is based on a previous DFT development that uses a perfect conductor (PC) model to approximate the electrostatic response of the metal substrate, while the film and the adsorbate are both treated fully within DFT [I. Scivetti and M. Persson, Journal of Physics: Condensed Matter 25, 355006 (2013)]. The missing int...

  14. Testing soil-like substrate for growing plants in bioregenerative life support systems

    Science.gov (United States)

    Gros, J. B.; Lasseur, Ch.; Tikhomirov, A. A.; Manukovsky, N. S.; Kovalev, V. S.; Ushakova, S. A.; Zolotukhin, I. G.; Tirranen, L. S.; Karnachuk, R. A.; Dorofeev, V. Yu.

    We studied soil-like substrate (SLS) as a potential candidate for plant cultivation in bioregenerative life support systems (BLSS). The SLS was obtained by successive conversion of wheat straw by oyster mushrooms and worms. Mature SLS contained 9.5% humic acids and 4.9% fulvic acids. First, it was shown that wheat, bean and cucumber yields as well as radish yields when cultivated on mature SLS were comparable to yields obtained on a neutral substrate (expanded clay aggregate) under hydroponics. Second, the possibility of increasing wheat and radish yields on the SLS was assessed at three levels of light intensity: 690, 920 and 1150 μmol m -2 s -1 of photosynthetically active radiation (PAR). The highest wheat yield was obtained at 920 μmol m -2 s -1, while radish yield increased steadily with increasing light intensity. Third, long-term SLS fertility was tested in a BLSS model with mineral and organic matter recycling. Eight cycles of wheat and 13 cycles of radish cultivation were carried out on the SLS in the experimental system. Correlation coefficients between SLS nitrogen content and total wheat biomass and grain yield were 0.92 and 0.97, respectively, and correlation coefficients between nitrogen content and total radish biomass and edible root yield were 0.88 and 0.87, respectively. Changes in hormone content (auxins, gibberellins, cytokinins and abscisic acid) in the SLS during matter recycling did not reduce plant productivity. Quantitative and species compositions of the SLS and irrigation water microflora were also investigated. Microbial community analysis of the SLS showed bacteria from Bacillus, Pseudomonas, Proteus, Nocardia, Mycobacterium, Arthrobacter and Enterobacter genera, and fungi from Trichoderma, Penicillium, Fusarium, Aspergillus, Mucor, Botrytis, and Cladosporium genera.

  15. Formation of substrate-supported membranes from mixtures of long- and short-chain phospholipids.

    Science.gov (United States)

    Morigaki, Kenichi; Kimura, Shigeki; Okada, Keisuke; Kawasaki, Takashi; Kawasaki, Kazunori

    2012-06-26

    We studied the formation of substrate-supported planar phospholipid bilayers (SPBs) on glass and silica from mixtures of long- and short-chain phospholipids to assess the effects of detergent additives on SPB formation. 1,2-Hexyanoyl-sn-glycero-3-phosphocholine (DHPC-C6) and 1,2-heptanoyl-sn-glycero-3-phosphocholine (DHPC-C7) were chosen as short-chain phospholipids. 1-Palmitoyl-2-oleol-sn-glycero-3-phosphocholine (POPC) was used as a model long-chain phospholipid. Kinetic studies by quartz crystal microbalance with dissipation monitoring (QCM-D) showed that the presence of short-chain phospholipids significantly accelerated the formation of SPBs. Rapid rinsing with a buffer solution did not change the adsorbed mass on the surface if POPC/DHPC-C6 mixtures were used below the critical micelle concentration (cmc) of DHPC-C6, indicating that an SPB composed of POPC molecules remained on the surface. Fluorescence microscopy observation showed homogeneous SPBs, and the fluorescence recovery after photobleaching (FRAP) measurements gave a diffusion coefficient comparable to that for SPBs formed from POPC vesicles. However, mixtures of POPC/DHPC-C7 resulted in a smaller mass of lipid adsorption on the substrate. FRAP measurements also yielded significantly smaller diffusion coefficients, suggesting the presence of defects. The different behaviors for DHPC-C6 and DHPC-C7 point to the dual roles of detergents to enhance the formation of SPBs and to destabilize them, depending on their structures and aggregation properties.

  16. Electrospun silk fibroin/poly(lactide-co-ε-caprolactone nanofibrous scaffolds for bone regeneration

    Directory of Open Access Journals (Sweden)

    Wang Z

    2016-04-01

    Full Text Available Zi Wang,1,* Ming Lin,1,* Qing Xie,1 Hao Sun,1 Yazhuo Huang,1 DanDan Zhang,1 Zhang Yu,1 Xiaoping Bi,1 Junzhao Chen,1 Jing Wang,2 Wodong Shi,1 Ping Gu,1 Xianqun Fan1 1Department of Ophthalmology, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, 2Biomaterials and Tissue Engineering Laboratory, College of Chemistry & Chemical Engineering and Biotechnology, Donghua University, Shanghai, People’s Republic of China *These authors contributed equally to this work Background: Tissue engineering has become a promising therapeutic approach for bone regeneration. Nanofibrous scaffolds have attracted great interest mainly due to their structural similarity to natural extracellular matrix (ECM. Poly(lactide-co-ε-caprolactone (PLCL has been successfully used in bone regeneration, but PLCL polymers are inert and lack natural cell recognition sites, and the surface of PLCL scaffold is hydrophobic. Silk fibroin (SF is a kind of natural polymer with inherent bioactivity, and supports mesenchymal stem cell attachment, osteogenesis, and ECM deposition. Therefore, we fabricated hybrid nanofibrous scaffolds by adding different weight ratios of SF to PLCL in order to find a scaffold with improved properties for bone regeneration.Methods: Hybrid nanofibrous scaffolds were fabricated by blending different weight ratios of SF with PLCL. Human adipose-derived stem cells (hADSCs were seeded on SF/PLCL nanofibrous scaffolds of various ratios for a systematic evaluation of cell adhesion, proliferation, cytotoxicity, and osteogenic differentiation; the efficacy of the composite of hADSCs and scaffolds in repairing critical-sized calvarial defects in rats was investigated.Results: The SF/PLCL (50/50 scaffold exhibited favorable tensile strength, surface roughness, and hydrophilicity, which facilitated cell adhesion and proliferation. Moreover, the SF/PLCL (50/50 scaffold promoted the osteogenic differentiation of hADSCs by elevating the

  17. Effect of Cadmium Concentration on Structural, Optical, and Electrical Properties of Cu2Zn1−xCdxSnS4 Quinternary Alloy Nanofibres, Synthesized by Electrospinning Technique

    Directory of Open Access Journals (Sweden)

    A. S. Ibraheam

    2016-01-01

    Full Text Available The Cu2Zn1−xCdxSnS4 quinternary alloy nanofibres with different Cd concentrations were grown on glass substrate using the electrospinning technique. The structural properties of Cu2Zn1−xCdxSnS4 quinternary alloy nanofibres were investigated by X-ray diffraction (XRD, field emission-scanning electron microscopy (FE-SEM, and atomic force microscopy (AFM. Optical properties were analysed through UV-visible spectrophotometry (UV-Vis and photoluminescence (PL spectroscopy, which revealed that there is a decrease in band gap from 1.75 eV to 1.61 eV, with the increasing Cd concentration from x = 0 to x = 1. The current-voltage measurements exhibited a power conversion efficiency of 3% under the solar illumination with intensity of 100 mW/cm2. Electrical properties supported that the Cu2Zn1−xCdxSnS4 quinternary alloy can be used as an absorber in solar cells. The bulk modulus, refractive index, and dielectric constant were also investigated.

  18. Synthesis of Vertically Aligned Carbon Nanotubes on Silicalite-1 Monolayer-Supported Substrate

    Directory of Open Access Journals (Sweden)

    Wei Zhao

    2014-01-01

    Full Text Available Monodisperse magnetic Fe3O4 nanoparticles (NPs with the size of ca. 3.5 nm were prepared and used as the catalysts for the synthesis of vertically aligned carbon nanotube (VACNT arrays. A silicalite-1 microcrystal monolayer was used as the support layer between catalyst NPs and the silicon substrate. Compared to our previous report which used radio-frequency- (rf- sputtered Fe2O3 film as the catalyst, Fe3O4 NPs that were synthesized by wet chemical method showed an improved catalytic ability with less agglomeration. The silicalite-1 crystal monolayer acted as an effective “buffer” layer to prevent the catalyst NPs from agglomerating during the reaction process. It is believed that this is the first report that realizes the vertical alignment of CNTs over the zeolite monolayer, namely, silicalite-1 microcrystal monolayer, instead of using the intermediate anodic aluminum oxide (AAO scaffold to regulate the growth direction of CNT products.

  19. Self-Assembly of 2D TMV Arrays on Substrate-Supported and Langmuir Lipid Monolayers

    Science.gov (United States)

    Wang, Suntao; Checco, Antonio; Niu, Zhongwei; Wang, Qian; Fukuto, Masafumi; Yang, Lin

    2008-03-01

    Bionanoparticles (large proteins, viruses) are ideal building blocks for creating ordered two-dimensional (2D) arrays. These 2D protein crystals or ordered arrays are of great scientific and technological interest. Here, we demonstrate the use of in-situ x-ray scattering and Brewster angle microscopy (BAM) to monitor the formation of self-assembled, 2D ordered arrays by tobacco mosaic viruses (TMVs) on a lipid layer that was either supported by a solid substrate or formed at the liquid-vapor interface. The lipid monolayer not only confined the viral particles within a plane, but also provided the lateral mobility that is crucial for developing structural order. In-situ X-ray scattering was used to provide real time information on the structure of the virus array and guide optimizations of the surrounding chemical environment to improve in-plane structural order. The presence of Ca^2+ ions is also essential to the formation of well ordered, closely packed 2D arrays of TMV. Atomic Force Microscopy was also used to directly image the final structure to provide real space confirmation of developed structural order.

  20. Low-cost flexible supercapacitors based on laser reduced graphene oxide supported on polyethylene terephthalate substrate

    Science.gov (United States)

    Ghoniem, Engy; Mori, Shinsuke; Abdel-Moniem, Ahmed

    2016-08-01

    A controlled high powered CO2 laser system is used to reduce and pattern graphene oxide (GO) film supported onto a flexible polyethylene terephthalate (PET) substrate. The laser reduced graphene oxide (rGO) film is characterized and evaluated electrochemically in the absence and presence of an overlying anodicaly deposited thin film of pseuodcapactive MnO2 as electrodes for supercapacitor applications using aqueous electrolyte. The laser treatment of the GO film leads to an overlapped structure of defective multi-layer rGO sheets with an electrical conductivity of 273 S m-1. The rGO and MnO2/rGO electrodes exhibit specific capacitance in the range of 82-107 and 172-368 Fg-1 at applied current range of 0.1-1.0 mA cm-2 and retain 98 and 95% of their initial capacitances after 2000 cycles at a current density of 1.0 mA cm-2, respectively. Also, the rGO is assigned as an electrode material for flexible conventionally stacked and interdigitated in-plane supercapacitor structures using gel electrolyte. Three electrode architectures of 2, 4, and 6 sub-electrodes are studied for the interdigital in-plane design. The device with interdigital 6 sub-electrodes architecture I-PS(6) delivers power density of 537.1 Wcm-3 and an energy density of 0.45 mWh cm-3.

  1. Effect of SiO2 substrate on the irradiation-assisted manipulation of supported graphene: a molecular dynamics study.

    Science.gov (United States)

    Zhao, Shijun; Xue, Jianming; Wang, Yugang; Yan, Sha

    2012-07-20

    The irradiation effects in graphene supported by SiO(2) substrate including defect production and implantation efficiency are investigated using the molecular dynamics (MD) method with empirical potentials. We show that the irradiation damage in supported graphene comes from two aspects: the direct damage induced by the incident ions and the indirect damage resulting from backscattered particles and sputtered atoms from the substrate. In contrast with the damage in suspended graphene, we find that the indirect damage is dominant in supported graphene at high energies. As a result, enhanced irradiation damage in supported graphene is observed when the incident energy is above 5 keV for Ar and 3 keV for Si. The direct damage probability at all energies, even the total damage probability at low energies, in supported graphene is always much lower than that in suspended graphene because of the higher threshold displacement energy of carbon atoms. In addition, we demonstrate the striking finding that it is possible to dope graphene with sputtered atoms from the substrate and the implantation probability is considerable at optimal energies. Our results indicate that the substrate is an important factor in the process of ion-irradiation-assisted engineering of the properties of graphene.

  2. Fabrication and Characterization of Electrospun Polycaprolactone Blended with Chitosan-Gelatin Complex Nanofibrous Mats

    Directory of Open Access Journals (Sweden)

    Yongfang Qian

    2014-01-01

    Full Text Available Design and fabrication of nanofibrous scaffolds should mimic the native extracellular matrix. This study is aimed at investigating electrospinning of polycaprolactone (PCL blended with chitosan-gelatin complex. The morphologies were observed from scanning electron microscope. As-spun blended mats had thinner fibers than pure PCL. X-ray diffraction was used to analyze the degree of crystallinity. The intensity at two peaks at 2θ of 21° and 23.5° gradually decreased with the percentage of chitosan-gelatin complex increasing. Moreover, incorporation of the complex could obviously improve the hydrophilicity of as-spun blended mats. Mechanical properties of as-spun nanofibrous mats were also tested. The elongation at break of fibrous mats increased with the PCL content increasing and the ultimate tensile strength varied with different weight ratios. The as-spun mats had higher tensile strength when the weight ratio of PCL to CS-Gel was 75/25 compared to pure PCL. Both as-spun PCL scaffolds and PCL/CS-Gel scaffolds supported the proliferation of porcine iliac endothelial cells, and PCL/CS-Gel had better cell viability than pure PCL. Therefore, electrospun PCL/Chitosan-gelatin nanofibrous mats with weight ratio of 75/25 have better hydrophilicity mechanical properties, and cell proliferation and thus would be a promising candidate for tissue engineering scaffolds.

  3. PGS:Gelatin Nanofibrous Scaffolds with Tunable Mechanical and Structural Properties for Engineering Cardiac Tissues

    Science.gov (United States)

    Kharaziha, Mahshid; Nikkhah, Mehdi; Shin, Su-Ryon; Annabi, Nasim; Masoumi, Nafiseh; Gaharwar, Akhilesh K.; Camci-Unal, Gulden; Khademhosseini, Ali

    2013-01-01

    A significant challenge in cardiac tissue engineering is the development of biomimetic grafts that can potentially promote myocardial repair and regeneration. A number of approaches have used engineered scaffolds to mimic the architecture of the native myocardium tissue and precisely regulate cardiac cell functions. However previous attempts have not been able to simultaneously recapitulate chemical, mechanical, and structural properties of the myocardial extracellular matrix (ECM). In this study, we utilized an electrospinning approach to fabricate elastomeric biodegradable poly(glycerol-sebacate) (PGS):gelatin scaffolds with a wide range of chemical composition, stiffness and anisotropy. Our findings demonstrated that through incorporation of PGS, it is possible to create nanofibrous scaffolds with well-defined anisotropy that mimics the left ventricular myocardium architecture. Furthermore, we studied attachment, proliferation, differentiation and alignment of neonatal rat cardiac fibroblast cells (CFs) as well as protein expression, alignment, and contractile function of cardiomyocyte (CMs) on PGS:gelatin scaffolds with variable amount of PGS. Notably, aligned nanofibrous scaffold, consisting of 33 wt. % PGS, induced optimal synchronous contractions of CMs while significantly enhanced cellular alignment. Overall, our study suggests that the aligned nanofibrous PGS:gelatin scaffold support cardiac cell organization, phenotype and contraction and could potentially be used to develop clinically relevant constructs for cardiac tissue engineering. PMID:23747008

  4. Characterisation and cooperative antimicrobial properties of chitosan/nano-ZnO composite nanofibrous membranes.

    Science.gov (United States)

    Wang, Yan; Zhang, Qun; Zhang, Chen-Lu; Li, Ping

    2012-05-01

    Chitosan was combined with nano-ZnO to increase its antimicrobial activity, using polyvinyl alcohol as a support, and then were electronspun to form composite nanofibres. Through SEM, EDX and XRD observations, chitosan was seen to be able to incorporate nano-ZnO in the composite nanofibres. Escherichia coli, expressing recombinant enhanced green fluorescent protein, and Candida albicans were used to test the antimicrobial efficacy of the newly synthesised chitosan/nano-ZnO antimicrobial composite. The CdTe quantum dots were used to rapidly detect the residual changes of C. albicans and determine the end point of using antimicrobial agents. Minimal minimum inhibitory concentration (MIC), post-antibiotic effect and continuous agent effect of the composite were determined. The MIC of chitosan/nano-ZnO against C. albicans was 160μg/ml, close to the concentration of the treated composite with the lowest fluorescence intensity. The cell damage was observed by SEM, which indicated that nano-ZnO in the nanofibrous membranes played a cooperative role in the antimicrobial process of chitosan.

  5. Biocompatibility evaluation of electrospun aligned poly(propylene carbonate) nanofibrous scaffolds with peripheral nerve tissues and cells in vitro

    Institute of Scientific and Technical Information of China (English)

    WANG Yu; ZHAO Zhe; ZHAO Bin; QI Hong-xu; PENG Jiang; ZHANG Li; XU Wen-jing; HU Ping; LU Shi-bi

    2011-01-01

    Background Peripheral nerve regeneration across large gaps is clinically challenging. Scaffold design plays a pivotal role in nerve tissue engineering. Recently, nanofibrous scaffolds have proven a suitable environment for cell attachment and proliferation due to similarities of their physical properties to natural extracellular matrix. Poly(propylene carbonate)(PPC) nanofibrous scaffolds have been investigated for vascular tissue engineering. However, no reports exist of PPC nanofibrous scaffolds for nerve tissue engineering. This study aimed to evaluate the potential role of aligned and random PPC nanofibrous scaffolds as substrates for peripheral nerve tissue and cells in nerve tissue engineering. Methods Aligned and random PPC nanofibrous scaffolds were fabricated by electrospinning and their chemical characterization were carried out using scanning electron microscopy (SEM). Dorsal root ganglia (DRG) from Sprague-Dawley rats were cultured on the nanofibrous substrates for 7 days. Neurite outgrowth and Schwann-cell migration from DRG were observed and quantified using immunocytochemistry and SEM. Schwann cells derived from rat sciatic nerves were cultured in electrospun PPC scaffold-extract fluid for 24, 48, 72 hours and 7 days. The viability of Schwann cells was evaluated by 3-[4,5-dimethyl(thiazol-2-yl)-2,5-diphenyl] tetrazolium bromide (MTT) assay. Results The diameter of aligned and random fibers ranged between 800 nm and 1200 nm, and the thickness of the films was approximately 10-20 μm. Quantification of aligned fiber films revealed approximately 90% alignment of all fibers along the longitudinal axis. However, with random fiber films, the alignment of fibers was random through all angle bins. Rat DRG explants were grown on PPC nanofiber films for up to 1 week. On the aligned fiber films, the majority of neurite outgrowth and Schwann cell migration from the DRG extended unidirectionally, parallel to the aligned fibers.However, on the random fiber films

  6. V2O5 nanofibre sheet actuators

    Science.gov (United States)

    Gu, Gang; Schmid, Michael; Chiu, Po-Wen; Minett, Andrew; Fraysse, Jerôme; Kim, Gyu-Tae; Roth, Siegmar; Kozlov, Mikhail; Muñoz, Edgar; Baughman, Ray H.

    2003-05-01

    Vanadium oxides, such as V2O5, are promising for lithium-ion batteries, catalysis, electrochromic devices and sensors. Vanadium oxides were proposed more than a decade ago for another redox-dependent application: the direct conversion of electrical energy to mechanical energy in actuators (artificial muscles). Although related conducting polymer and carbon nanotube actuators have been demonstrated, electromechanical actuators based on vanadium oxides have not be realized. V2O5 nanofibres and nanotubes provide the potential advantages of low-cost synthesis by sol-gel routes and high charging capacity and long cycle life. Here, we demonstrate electromechanical actuation for obtained high modulus V2O5 sheets comprising entangled V2O5 nanofibres. The high surface area of these V2O5 sheets facilitates electrochemical charge injection and intercalation that causes the electromechanical actuation. We show that the V2O5 sheets provide high Young's modulus, high actuator-generated stress, and high actuator stroke at low applied voltage.

  7. Investigating consistency and physical properties of ambient multilayer Au/Cr films on substrate support via SEM/EDX

    Science.gov (United States)

    Turner, Daniel; Senevirathne, Indrajith

    2015-03-01

    Study of adhesion, consistency and structure of multilayer, noble/wider-refractory metallic films are increasingly important industry and surface engineering/physics. In this study Au/Cr/substrate, and Cr/substrate multilayer films are studied for their consistency and structure. Soda lime glass and polycrystalline quartz were used for substrate support. Substrates were removed of organic impurities. Typical Cr depositions on substrates above shown to give rise to Stanski-Krastonov (SK) like growth. Cr was thermally evaporated with thickness of 100nm. In some samples an additional Au layer (20nm) is then deposited via magnetron sputter deposition at 100mtorr at low deposition rates (1ML/min) onto the Cr film. Systems were investigated via Scanning Electron Microscopy (SEM) to examine the surface consistency and possible oxidization. Further, the ambient contamination, elemental composition and thermal diffusion were investigated via Energy Dispersive X-ray spectroscopy (EDX). Cr film has a high affinity to ambient Oxygen and shown to form jagged distributed surface irregularities. These were observed to be dependent on substrate consistency and the degree of contamination.

  8. Characterization and application of chondroitin sulfate/polyvinyl alcohol nanofibres prepared by electrospinning.

    Science.gov (United States)

    Guo, Junxia; Zhou, Huitong; Akram, Muhammad Yasir; Mu, Xueyan; Nie, Jun; Ma, Guiping

    2016-06-05

    Composite nanofibres were prepared by electrospinning from a solution of chondroitin sulfate and polyvinyl alcohol. The chondroitin sulfate/polyvinyl alcohol (CS/PVA) mass ratios of 7/3 has a uniform and smooth morphology, and the average diameter of the nanofibres was 136nm. Combretastatin A-4 phosphate was loaded on the nanofibres and used as a model for testing drug release from the nanofibres crosslinked with glutaric dialdehyde. The morphology and structure of the nanofibres was determined using scanning electron microscopy. In order to assess their possible application to tissue engineering scaffolds, the toxicity and cytocompatibility of the nanofibres were tested by methylthiazolydiphenyl-tetrazolium bromide assay.

  9. A simplified density functional theory method for investigating charged adsorbates on an ultrathin, insulating film supported by a metal substrate.

    Science.gov (United States)

    Scivetti, Ivan; Persson, Mats

    2014-04-02

    A simplified density functional theory (DFT) method for investigating charged adsorbates on an ultrathin, insulating film supported by a metal substrate is developed and presented. This new method is based on a previous DFT development that uses a perfect conductor (PC) model to approximate the electrostatic response of the metal substrate, while the film and the adsorbate are both treated fully within DFT (Scivetti and Persson 2013 J. Phys.: Condens. Matter 25 355006). The missing interactions between the metal substrate and the insulating film in the PC approximation are modelled by a simple force field (FF). The parameters of the PC model and the force field are obtained from DFT calculations of the film and the substrate, here shown explicitly for a NaCl bilayer supported by a Cu(100) surface. In order to obtain some of these parameters and the polarizability of the force field, we have to include an external, uniformly charged plane in the DFT calculations, which has required the development of a periodic DFT formalism to include such a charged plane in the presence of a metal substrate. This extension and implementation should be of more general interest and applicable to other challenging problems, for instance, in electrochemistry. As illustrated for the gold atom on the NaCl bilayer supported by a Cu(100) surface, our new DFT-PC-FF method allows us to handle different charge states of adsorbates in a controlled and accurate manner with a considerable reduction of the computational time. In addition, it is now possible to calculate vertical transition and reorganization energies for the charging and discharging of adsorbates that cannot be obtained by current DFT methodologies that include the metal substrate. We find that the computed vertical transition energy for charging of the gold adatom is in good agreement with experiments.

  10. Gum tragacanth/poly(l-lactic acid) nanofibrous scaffolds for application in regeneration of peripheral nerve damage.

    Science.gov (United States)

    Ranjbar-Mohammadi, Marziyeh; Prabhakaran, Molamma P; Bahrami, S Hajir; Ramakrishna, Seeram

    2016-04-20

    Nanofibrous nerve guides have gained huge interest in supporting the peripheral nerve regeneration due to their abilities to simulate the topography, mechanical, biological and extracellular matrix morphology of native tissue. Gum tragacanth (GT) is a biocompatible mixture of polysaccharides that has been used in biomedical applications. During this study, we fabricated aligned and random nanofibers from poly(l-lactic acid) and gum tragacanth (PLLA/GT) in various ratios (100:0, 75:25, and 50:50) by electrospinning. Scanning electron microscope demonstrated smooth and uniform nanofibers with diameters in the range of 733±65nm and 226±73nm for align PLLA and random PLLA/GT 50:50 nanofibers, respectively. FTIR analysis, contact angle, in vitro biodegradation and tensile measurements were carried out to evaluate the chemical and mechanical properties of the different scaffolds. PLLA/GT 75:25 exhibited the most balanced properties compared to other scaffolds and was used for in vitro culture of nerve cells (PC12) to assess the potential of using these scaffolds as a substrate for nerve regeneration. The cells were found to attach and proliferate on aligned PLLA/GT 75:25 scaffolds, expressing bi-polar neurite extensions and the orientation of nerve cells was along the direction of the fiber alignment. Results of 8 days of in vitro culture of PC12 cells on aligned PLLA/GT 75:25 nanofibers, showed 20% increase in cell proliferation compared to PLLA/GT 75:25 random nanofibers. PLLA/GT 75:25 aligned nanofibers acted as a favorable cue to support neurite outgrowth and nerve cell elongation compared with PLLA nanofibers. Our results showed that aligned PLLA/GT 75:25 nanofibers are promising substrates for application as bioengineered grafts for nerve tissue regeneration. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Functionalisation of the carbon nanofibres by plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Brandl, W.; Marginean, G

    2004-01-30

    Vapour grown carbon nanofibres (VGCNF) were surface modified through cold oxygen plasma treatment under reduced pressure. The fibre morphology was studied by SEM (scanning electron microscopy) and HRTEM (high resolution transmission electron microscopy). The nanofibres surface functionalisation was elucidated by NaOH-titration, contact angle and surface energy measurements of the carbon nanofibres before and after plasma treatment. Oxygen plasma treatment introduced oxygen containing functional groups (hydroxylic, carbonylic and carboxylic groups) onto the fibre surfaces and also enhanced the fibre surface porosity (by etching) as well as the surface energy. There is yet to be mentioned that the fibre modifications have to occur only in the first few atomic layers. The plasma treatment can be proposed as a suitable method to change nanofibres surface from hydrophobic to hydrophilic.

  12. Electrospun nanofibres in agriculture and the food industry: a review.

    Science.gov (United States)

    Noruzi, Masumeh

    2016-11-01

    The interesting characteristics of electrospun nanofibres, such as high surface-to-volume ratio, nanoporosity, and high safety, make them suitable candidates for use in a variety of applications. In the recent decade, electrospun nanofibres have been applied to different potential fields such as filtration, wound dressing, drug delivery, etc. and a significant number of review papers have been published in these fields. However, the use of electrospun nanofibres in agriculture is comparatively novel and is still in its infancy. In this paper, the specific applications of electrospun nanofibres in agriculture and food science, including plant protection using pheromone-loaded nanofibres, plant protection using encapsulation of biocontrol agents, preparation of protective clothes for farm workers, encapsulation of agrochemical materials, deoxyribonucleic acid extraction in agricultural research studies, pre-concentration and measurement of pesticides in crops and environmental samples, preparation of nanobiosensors for pesticide detection, encapsulation of food materials, fabrication of food packaging materials, and filtration of beverage products are reviewed and discussed. This paper may help researchers develop the use of electrospun nanofibres in agriculture and food science to address some serious problems such as the intensive use of pesticides. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  13. Basal Lamina Mimetic Nanofibrous Peptide Networks for Skeletal Myogenesis

    Science.gov (United States)

    Yasa, I. Ceren; Gunduz, Nuray; Kilinc, Murat; Guler, Mustafa O.; Tekinay, Ayse B.

    2015-11-01

    Extracellular matrix (ECM) is crucial for the coordination and regulation of cell adhesion, recruitment, differentiation and death. Therefore, equilibrium between cell-cell and cell-matrix interactions and matrix-associated signals are important for the normal functioning of cells, as well as for regeneration. In this work, we describe importance of adhesive signals for myoblast cells’ growth and differentiation by generating a novel ECM mimetic peptide nanofiber scaffold system. We show that not only structure but also composition of bioactive signals are important for cell adhesion, growth and differentiation by mimicking the compositional and structural properties of native skeletal muscle basal lamina. We conjugated laminin-derived integrin binding peptide sequence, “IKVAV”, and fibronectin-derived well known adhesive sequence, “RGD”, into peptide nanostructures to provide adhesive and myogenic cues on a nanofibrous morphology. The myogenic and adhesive signals exhibited a synergistic effect on model myoblasts, C2C12 cells. Our results showed that self-assembled peptide nanofibers presenting laminin derived epitopes support adhesion, growth and proliferation of the cells and significantly promote the expression of skeletal muscle-specific marker genes. The functional peptide nanofibers used in this study present a biocompatible and biodegradable microenvironment, which is capable of supporting the growth and differentiation of C2C12 myoblasts into myotubes.

  14. Nanofibrous membrane-based absorption refrigeration system

    Energy Technology Data Exchange (ETDEWEB)

    Isfahani, RN; Sampath, K; Moghaddam, S

    2013-12-01

    This paper presents a study on the efficacy of highly porous nanofibrous membranes for application in membrane-based absorbers and desorbers. Permeability studies showed that membranes with a pore size greater than about one micron have a sufficient permeability for application in the absorber heat exchanger. Membranes with smaller pores were found to be adequate for the desorber heat exchanger. The membranes were implemented in experimental membrane-based absorber and desorber modules and successfully tested. Parametric studies were conducted on both absorber and desorber processes. Studies on the absorption process were focused on the effects of water vapor pressure, cooling water temperature, and the solution velocity on the absorption rate. Desorption studies were conducted on the effects of wall temperature, vapor and solution pressures, and the solution velocity on the desorption rate. Significantly higher absorption and desorption rates than in the falling film absorbers and desorbers were achieved. Published by Elsevier Ltd.

  15. Shape-Related Toxicity of Titanium Dioxide Nanofibres.

    Directory of Open Access Journals (Sweden)

    Manfredi Allegri

    Full Text Available Titanium dioxide (TiO2 nanofibres are a novel fibrous nanomaterial with increasing applications in a variety of fields. While the biological effects of TiO2 nanoparticles have been extensively studied, the toxicological characterization of TiO2 nanofibres is far from being complete. In this study, we evaluated the toxicity of commercially available anatase TiO2 nanofibres using TiO2 nanoparticles (NP and crocidolite asbestos as non-fibrous or fibrous benchmark materials. The evaluated endpoints were cell viability, haemolysis, macrophage activation, trans-epithelial electrical resistance (an indicator of the epithelial barrier competence, ROS production and oxidative stress as well as the morphology of exposed cells. The results showed that TiO2 nanofibres caused a cell-specific, dose-dependent decrease of cell viability, with larger effects on alveolar epithelial cells than on macrophages. The observed effects were comparable to those of crocidolite, while TiO2 NP did not decrease cell viability. TiO2 nanofibres were also found endowed with a marked haemolytic activity, at levels significantly higher than those observed with TiO2 nanoparticles or crocidolite. Moreover, TiO2 nanofibres and crocidolite, but not TiO2 nanoparticles, caused a significant decrease of the trans-epithelial electrical resistance of airway cell monolayers. SEM images demonstrated that the interaction with nanofibres and crocidolite caused cell shape perturbation with the longest fibres incompletely or not phagocytosed. The expression of several pro-inflammatory markers, such as NO production and the induction of Nos2 and Ptgs2, was significantly increased by TiO2 nanofibres, as well as by TiO2 nanoparticles and crocidolite. This study indicates that TiO2 nanofibres had significant toxic effects and, for most endpoints with the exception of pro-inflammatory changes, are more bio-active than TiO2 nanoparticles, showing the relevance of shape in determining the toxicity of

  16. Shape-Related Toxicity of Titanium Dioxide Nanofibres

    Science.gov (United States)

    Allegri, Manfredi; Bianchi, Massimiliano G.; Chiu, Martina; Varet, Julia; Costa, Anna L.; Ortelli, Simona; Blosi, Magda; Bussolati, Ovidio; Poland, Craig A.; Bergamaschi, Enrico

    2016-01-01

    Titanium dioxide (TiO2) nanofibres are a novel fibrous nanomaterial with increasing applications in a variety of fields. While the biological effects of TiO2 nanoparticles have been extensively studied, the toxicological characterization of TiO2 nanofibres is far from being complete. In this study, we evaluated the toxicity of commercially available anatase TiO2 nanofibres using TiO2 nanoparticles (NP) and crocidolite asbestos as non-fibrous or fibrous benchmark materials. The evaluated endpoints were cell viability, haemolysis, macrophage activation, trans-epithelial electrical resistance (an indicator of the epithelial barrier competence), ROS production and oxidative stress as well as the morphology of exposed cells. The results showed that TiO2 nanofibres caused a cell-specific, dose-dependent decrease of cell viability, with larger effects on alveolar epithelial cells than on macrophages. The observed effects were comparable to those of crocidolite, while TiO2 NP did not decrease cell viability. TiO2 nanofibres were also found endowed with a marked haemolytic activity, at levels significantly higher than those observed with TiO2 nanoparticles or crocidolite. Moreover, TiO2 nanofibres and crocidolite, but not TiO2 nanoparticles, caused a significant decrease of the trans-epithelial electrical resistance of airway cell monolayers. SEM images demonstrated that the interaction with nanofibres and crocidolite caused cell shape perturbation with the longest fibres incompletely or not phagocytosed. The expression of several pro-inflammatory markers, such as NO production and the induction of Nos2 and Ptgs2, was significantly increased by TiO2 nanofibres, as well as by TiO2 nanoparticles and crocidolite. This study indicates that TiO2 nanofibres had significant toxic effects and, for most endpoints with the exception of pro-inflammatory changes, are more bio-active than TiO2 nanoparticles, showing the relevance of shape in determining the toxicity of nanomaterials

  17. Surface Modification of Electrospun PVDF/PAN Nanofibrous Layers by Low Vacuum Plasma Treatment

    OpenAIRE

    Fatma Yalcinkaya; Baturalp Yalcinkaya; Adam Pazourek; Jana Mullerova; Martin Stuchlik; Jiri Maryska

    2016-01-01

    Nanofibres are very promising for water remediation due to their high porosity and small pore size. Mechanical properties of nanofibres restrict the application of pressure needed water treatments. Various PAN, PVDF, and PVDF/PAN nanofibre layers were produced, and mechanical properties were improved via a lamination process. Low vacuum plasma treatment was applied for the surface modification of nanofibres. Atmospheric air was used to improve hydrophilicity while sulphur hexafluoride gas was...

  18. Ultrafast direct fabrication of flexible substrate-supported designer plasmonic nanoarrays

    Science.gov (United States)

    Hu, Yaowu; Kumar, Prashant; Xu, Rong; Zhao, Kejie; Cheng, Gary J.

    2015-12-01

    Fabrication of plasmonic nanostructures has been an important topic for their potential applications in photonic and optoelectronic devices. Among plasmonic materials, gold is one of the most promising materials due to its low ohmic loss at optical frequencies and high oxidation resistance. However, there are two major bottlenecks for its industrial applications: (1) the need for large-scale fabrication technology for high-precision plasmonic nanostructures; and (2) the need to integrate the plasmonic nanostructures on various substrates. While conventional top-down approaches involve high cost and give low throughput, bottom-up approaches suffer from irreproducibility and low precision. Herein, we report laser shock induced direct imprinting of large-area plasmonic nanostructures from physical vapor deposited (PVD) gold thin film on a flexible commercial free-standing aluminum foil. Among the important characteristics of the laser-shock direct imprinting is their unique capabilities to reproducibly deliver designer plasmonic nanostructures with extreme precision and in an ultrafast manner. Excellent size tunability (from several μm down to 15 nm) has been achieved by varying mold dimensions and laser parameters. The physical mechanism of the hybrid film imprinting is elaborated by finite element modeling. A mechanical robustness test of the hybrid film validates a significantly improved interfacial contact between gold arrays and the underlying substrate. The strong optical field enhancement was realized in the large-area fabricated engineered gold nanostructures. Low concentration molecular sensing was investigated employing the fabricated structures as surface-enhanced Raman scattering (SERS) substrates. The ability to ultrafast direct imprint plasmonic nanoarrays on a flexible substrate at multiscale is a critical step towards roll-to-roll manufacturing of multi-functional devices which is poised to inspire several emerging applications.Fabrication of

  19. Effect of substrate interface on the magnetism of supported iron nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Balan, A. [Swiss Light Source, Paul Scherrer Institut (PSI), Villigen CH-5232 (Switzerland); Fraile Rodríguez, A. [Departament de Física Fonamental and Institut de Nanociència i Nanotecnologia (IN2UB), Universitat de Barcelona, E-08028 Barcelona (Spain); Vaz, C.A.F.; Kleibert, A.; Nolting, F. [Swiss Light Source, Paul Scherrer Institut (PSI), Villigen CH-5232 (Switzerland)

    2015-12-15

    In situ X-ray photo-emission electron microscopy is used to investigate the magnetic properties of iron nanoparticles deposited on different single crystalline substrates, including Si(001), Cu(001), W(110), and NiO(001). We find that, in our room temperature experiments, Fe nanoparticles deposited on Si(001) and Cu(001) show both superparamagnetic and magnetically stable (blocked) ferromagnetic states, while Fe nanoparticles deposited on W(110) and NiO(001) show only superparamagnetic behaviour. The dependence of the magnetic behaviour of the Fe nanoparticles on the contact surface is ascribed to the different interfacial bonding energies, higher for W and NiO, and to a possible relaxation of point defects within the core of the nanoparticles on these substrates, that have been suggested to stabilise the ferromagnetic state at room temperature when deposited on more inert surfaces such as Si and Cu. - Highlights: • In situ X-ray photo-emission electron microscopy study on iron nanoparticles. • Magnetically blocked particles are found on Si(001) and Cu(001). • Superparamagnetic particles are found on W(110) and Ni0(001). • The substrate dependent behavior is ascribed to the different bonding energies.

  20. Composite poly-L-lactic acid/poly-(α,β)-DL-aspartic acid/collagen nanofibrous scaffolds for dermal tissue regeneration.

    Science.gov (United States)

    Ravichandran, Rajeswari; Venugopal, Jayarama Reddy; Sundarrajan, Subramanian; Mukherjee, Shayanti; Sridhar, Radhakrishnan; Ramakrishna, Seeram

    2012-08-01

    Tissue engineering scaffolds for skin tissue regeneration is an ever expounding area of research, as the products that meet the necessary requirements are far and elite. The nanofibrous poly-L-lactic acid/poly-(α,β)-DL-aspartic acid/Collagen (PLLA/PAA/Col I&III) scaffolds were fabricated by electrospinning and characterized by SEM, contact angle and FTIR analysis for skin tissue regeneration. The cell-scaffold interactions were analyzed by cell proliferation and their morphology observed in SEM. The results showed that the cell proliferation was significantly increased (p≤0.05) in PLLA/PAA/Col I&III scaffolds compared to PLLA and PLLA/PAA nanofibrous scaffolds. The abundance and accessibility of adipose derived stem cells (ADSCs) may prove to be novel cell therapeutics for dermal tissue regeneration. The differentiation of ADSCs was confirmed using collagen expression and their morphology by CMFDA dye extrusion technique. The current study focuses on the application of PLLA/PAA/Col I&III nanofibrous scaffolds for skin tissue engineering and their potential use as substrate for the culture and differentiation of ADSCs. The objective for inclusion of a novel cell binding moiety like PAA was to replace damaged extracellular matrix and to guide new cells directly into the wound bed with enhanced proliferation and overall organization. This combinatorial epitome of PLLA/PAA/Col I&III nanofibrous scaffold with stem cell therapy to induce the necessary paracrine signalling effect would favour faster regeneration of the damaged skin tissues.

  1. Polymer nanofibrous structures: Fabrication, biofunctionalization, and cell interactions.

    Science.gov (United States)

    Beachley, Vince; Wen, Xuejun

    2010-07-01

    Extracellular matrix fibers (ECM) such as collagen, elastin, and keratin provide biological and physical support for cell attachment, proliferation, migration, differentiation and ultimately cell fate. Therefore, ECM fibers are an important component in tissue and organ development and regeneration. Meanwhile, polymer nanofibers could play the same critical role in tissue regeneration process. Fibrous structures can be fabricated from a variety of materials and methods with diameters ranging throughout the size scale where cells can sense individual fibers (several nanometers to several microns). Polymer nanofiber scaffolds can be designed in a way that predictably modulates a variety of important cell behaviors towards a desired overall function. The nanofibrous topography itself, independent of the fiber material, has demonstrated the potential to modulate cell behaviors desirable in tissue engineering such as: unidirectional alignment; increased viability, attachment, and ECM production; guided migration; and controlled differentiation. The versatility of polymer nanofibers for functionalization with biomolecules opens the door to vast opportunities for the design of tissue engineering scaffolds with even greater control over cell incorporation and function. Despite the promise of polymer nanofibers as tissue engineering scaffolds there have been few clinically relevant successes because no single fabrication technique currently combines control over structural arrangement, material composition, and biofunctionalization, while maintaining reasonable cost and yield. Promising strategies are currently being investigated to allow for the fabrication of optimal polymer nanofiber tissue engineering scaffolds with the goal of treating damaged and degenerated tissues in a clinical setting.

  2. Polymer nanofibrous structures: Fabrication, biofunctionalization, and cell interactions

    Science.gov (United States)

    Beachley, Vince; Wen, Xuejun

    2010-01-01

    Extracellular matrix fibers (ECM) such as collagen, elastin, and keratin provide biological and physical support for cell attachment, proliferation, migration, differentiation and ultimately cell fate. Therefore, ECM fibers are an important component in tissue and organ development and regeneration. Meanwhile, polymer nanofibers could play the same critical role in tissue regeneration process. Fibrous structures can be fabricated from a variety of materials and methods with diameters ranging throughout the size scale where cells can sense individual fibers (several nanometers to several microns). Polymer nanofiber scaffolds can be designed in a way that predictably modulates a variety of important cell behaviors towards a desired overall function. The nanofibrous topography itself, independent of the fiber material, has demonstrated the potential to modulate cell behaviors desirable in tissue engineering such as: unidirectional alignment; increased viability, attachment, and ECM production; guided migration; and controlled differentiation. The versatility of polymer nanofibers for functionalization with biomolecules opens the door to vast opportunities for the design of tissue engineering scaffolds with even greater control over cell incorporation and function. Despite the promise of polymer nanofibers as tissue engineering scaffolds there have been few clinically relevant successes because no single fabrication technique currently combines control over structural arrangement, material composition, and biofunctionalization, while maintaining reasonable cost and yield. Promising strategies are currently being investigated to allow for the fabrication of optimal polymer nanofiber tissue engineering scaffolds with the goal of treating damaged and degenerated tissues in a clinical setting. PMID:20582161

  3. Ultrastable gold substrates: Properties of a support for high-resolution electron cryomicroscopy of biological specimens

    OpenAIRE

    Russo, Christopher J.; Passmore, Lori A.

    2016-01-01

    Electron cryomicroscopy (cryo-EM) allows structure determination of a wide range of biological molecules and specimens. All-gold supports improve cryo-EM images by reducing radiation-induced motion and image blurring. Here we compare the mechanical and electrical properties of all-gold supports to amorphous carbon foils. Gold supports are more conductive, and have suspended foils that are not compressed by differential contraction when cooled to liquid nitrogen temperatures. These measurement...

  4. Fabrication of Electrospun Polyamide-6/Chitosan Nanofibrous Membrane toward Anionic Dyes Removal

    Directory of Open Access Journals (Sweden)

    Mozhdeh Ghani

    2014-01-01

    Full Text Available Nanofibrous filter media of polyamide-6/chitosan were fabricated by electrospinning onto a satin fabric substrate and characterized by scanning electron microscopy (SEM, Fourier transform infrared spectroscopy (FTIR, and water contact angle (WCA. Anionic dye removal capability of the filter was investigated for Solophenyl Red 3BL and Polar Yellow GN, respectively, as acidic and direct dyes were investigated with respect to solution parameters (pH and initial dye concentration and membrane parameters (electrospinning time and chitosan ratio through filtration system. Experiments were designed using response surface methodology (RSM based on five-level central composite design (CCD with four parameters to maximize removal efficiency of the filter media. Moreover, the effect of parameters and their likely interactions on dye removal were investigated by mathematically developed models. The optimum values for solution pH, initial dye concentration, electrospinning time, and chitosan ratio were predicted to be 5, 50 mg/L, 4 hr, 30% and 5, 100 mg/L, 4 hr, 10%, respectively, for achieving 96% and 95% removal of Solophenyl Red 3BL and Polar Yellow GN. Evaluation of the estimation capability of applied models revealed that the models have a good agreement with experimental values. This study demonstrated that polyamide-6/chitosan nanofibrous membrane has an enormous applicable potential in dye removal from aqueous solutions.

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

    Science.gov (United States)

    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.

  6. Towards supported bolaamphiphile membranes for water filtration: Roles of lipid and substrate

    NARCIS (Netherlands)

    Kaufman, Y.; Grinberg, S.; Linder, C..; Heldman, E.; Gilron, J.; Shen, Yue-xiao; Kumar, M.; Lammertink, R.G.H.; Freger, V.

    2014-01-01

    Supported biomimetic membranes hold potential for applications such as biosensors and water purification by filtration. The current paper reports on the preparation of a supported bolaamphiphile membrane on two polymeric nanofiltration membranes: NF-270 made of polyamide with carboxylic surface char

  7. Use of a hexapod in diffraction measurements of substrate-supported crystals of organic semiconductors.

    Science.gov (United States)

    Yang, Lin; Yang, Hoichang

    2009-11-01

    Thin films of organic semiconductor prepared on substrates generally contain crystals that have one common crystal plane parallel to the substrate but random in-plane orientations. In diffraction measurements of these structures, it is often required to anchor the X-ray beam on a fixed spot on the sample, such as an optically visible crystallite or island. Here, a hexapod is used in place of a traditional multi-circle diffractometer to perform area-detector-based diffraction measurements on an actual device that contains 6,13-bis(triisopropyl-silyethynyl)-pentacene (TIPS-pentacene) crystals. The hexapod allows for sample rotations about any user-defined rotation center. Two types of complex sample motions have been programmed to characterize the structure of the TIPS-pentacene crystal: an in-plane powder average has been performed at a fixed grazing-incident angle to determine the lattice parameters of the crystal; then the in-plane component of the scattering vector was continuously rotated in transmission geometry to determine the local crystal orientation.

  8. Novel PVA/MOF Nanofibres: Fabrication, Evaluation and Adsorption of Lead Ions from Aqueous Solution

    Science.gov (United States)

    Shooto, Ntaote David; Dikio, Charity Wokwu; Wankasi, Donbebe; Sikhwivhilu, Lucky Mashudu; Mtunzi, Fanyana Moses; Dikio, Ezekiel Dixon

    2016-09-01

    Plain polyvinyl alcohol (PVA) nanofibres and novel polyvinyl alcohol benzene tetracarboxylate nanofibres incorporated with strontium, lanthanum and antimony ((PVA/Sr-TBC), (PVA/La-TBC) and (PVA/Sb-TBC)), respectively, where TBC is benzene 1,2,4,5-tetracarboxylate adsorbents, were fabricated by electrospinning. The as-prepared electrospun nanofibres were characterized by scanning electron microscope (SEM), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). Only plain PVA nanofibres followed the Freundlich isotherm with a correlation coefficient of 0.9814, while novel nanofibres (PVA/Sb-TBC, PVA/Sr-TBC and PVA/La-TBC) followed the Langmuir isotherm with correlation coefficients of 0.9999, 0.9994 and 0.9947, respectively. The sorption process of all nanofibres followed a pseudo second-order kinetic model. Adsorption capacity of novel nanofibres was twofold and more compared to that of plain PVA nanofibres. The thermodynamic studies: apparent enthalpy (Δ H°) and entropy (Δ S°), showed that the adsorption of Pb(II) onto nanofibres was spontaneous and exothermic. The novel nanofibres exhibited higher potential removal of Pb(II) ions than plain PVA nanofibres. Ubiquitous cations adsorption test was also investigated and studied.

  9. Electrospinning of silver nanoparticles loaded highly porous cellulose acetate nanofibrous membrane for treatment of dye wastewater

    Science.gov (United States)

    Wang, Ke; Ma, Qian; Wang, Shu-Dong; Liu, Hua; Zhang, Sheng-Zhong; Bao, Wei; Zhang, Ke-Qin; Ling, Liang-Zhong

    2016-01-01

    In this paper, silver nanoparticles (NPs) were reduced form silver nitrate. Morphology and distribution of the synthesized silver NPs were characterized. In order to obtain cellulose acetate (CA), nanofibrous membrane with high effective adsorption performance to carry silver NPs for treatment of dye wastewater, different solvent systems were used to fabricate CA nanofibrous membranes with different morphologies and porous structures via electrospinning. Morphologies and structures of the obtained CA nanofibrous membranes were compared by scanning electron microscopy (SEM), which showed that CA nanofibrous membrane obtained from acetone/dichloromethane (1/2, v/v) was with the highly porous structure. SEM, energy-dispersive spectrometry and Fourier transform infrared spectrometry showed that the silver NPs were effectively incorporated in the CA nanofibrous membrane and the addition of silver NPs did not damage the porous structure of the CA nanofibrous membrane. Adsorption of dye solution (rhodamine B aqueous solution) revealed that the highly porous CA nanofibrous membrane exhibited effective adsorption performance and the addition of silver NPs did not affect the adsorption of the dye. Antibacterial property of the CA nanofibrous membrane showed that the silver-loaded highly porous CA nanofibrous membrane had remarkable antibacterial property when compared to the CA nanofibrous membrane without silver NPs. The silver-loaded highly porous CA nanofibrous membrane could be considered as an ideal candidate for treatment of the dye wastewater.

  10. Electrospinning of PVDF nanofibrous membranes with controllable crystalline phases

    Science.gov (United States)

    Lei, Tingping; Zhu, Ping; Cai, Xiaomei; Yang, Le; Yang, Fan

    2015-07-01

    Effectively controlling crystalline phases of electrospun polyvinylidene fluoride (PVDF) nanofibers is crucial to produce membranes with special properties for specific applications. Here, the heating treatment during or after electrospinning has been investigated to determine an effective way to control crystalline phase of PVDF nanofibers. By simultaneously controlling the collector temperature and the flow rate during the fiber deposition, a comparatively lower temperature (≤70 °C) is required for obtaining α-, β-, or γ-phase-dominant nanofibrous membranes, whereas a much higher temperature (≥150 °C) is necessary for post-heating of already-deposited fibers. On the other hand, through finely tuning the heating during or after electrospinning, crosslinked nanofibrous membranes can be also obtained, which undoubtedly enhance mechanical performance of the membranes. Therefore, it is hopeful to fabricate high-performance electrospun PVDF nanofibrous membranes with synchronous control of crystalline phases and morphologies, which will further broaden the applications of PVDF materials.

  11. Fouling-tolerant nanofibrous polymer membranes for water treatment.

    Science.gov (United States)

    Lee, Jang-Woo; Jung, Jiyoung; Cho, Young Hoon; Yadav, Santosh Kumar; Baek, Kyung Youl; Park, Ho Bum; Hong, Soon Man; Koo, Chong Min

    2014-08-27

    Nafion/polyvinylidene fluoride (PVDF) nanofibrous membranes with electrostatically negative charges on the fiber surface were fabricated via electrospinning with superior water permeability and antifouling behaviors in comparison with the conventional microfiltration membranes. The fiber diameter and the resultant pore size in the nanofibrous membranes were easily controlled through tailoring the properties of the electrospinning solutions. The electrospun Nafion/PVDF nanofibrous membranes revealed high porosities (>80%) and high densities of sulfonate groups on the membrane surface, leading to praiseworthy water permeability. Unexpectedly, the water permeability was observed as proportional to the fiber diameter and pore size in the membrane. The presence of sulfonate groups on the membrane improved the antifouling performance against negatively charged oily foulants.

  12. Localized and guided electroluminescence from roll printed organic nanofibres

    DEFF Research Database (Denmark)

    Tavares, Luciana; Kjelstrup-Hansen, Jakob; Rubahn, Horst-Günter

    2012-01-01

    Here, we report localized, polarized, and waveguidedelectroluminescence (EL) from well aligned organic nanofibres integrated via roll printing on transistor platforms. The localized emission is due to the application of an AC voltage to the transistor gate electrodes, which causes sequential...... injection of holes and electrons into the organic material with subsequent charge carrier recombination and light emission from a small area near the metal-nanofibre interface. The polarization results from the mutually parallel ordering of the molecular constituents, in which the emitting dipole...... that this scheme can facilitate EL from a nanofibre made from a different type of molecule with altered spectral characteristics. The realization of an electrically biased organic nanoscale light-emitter demonstrates the ability to fabricate on-chip light sources with tunable emission spectrum via synthesis...

  13. Modal coupling of single photons to a nanofibre

    CERN Document Server

    Gaio, Michele; Castro-Lopez, Marta; Pisignano, Dario; Camposeo, Andrea; Sapienza, Riccardo

    2015-01-01

    Nanoscale quantum optics of individual light emitters placed in confined geometries is developing as an exciting new research field aiming at efficient manipulation of single-photons . This requires selective channelling of light into specific optical modes of nanophotonic structures. Hybrid photonic systems combining emitters with nanostructured media can yield this functionality albeit limited by the required nanometre-scale spatial and spectral coupling. Furthermore, assessing the coupling strength presents significant challenges and disentangling the different modal contribution is often impossible. Here, we show that momentum spectroscopy of individually addressed emitters, embedded in a nanofibre, can be used to quantify the modal coupling efficiency to the nanofibre modes. For free-standing polymer nanofibres doped with colloidal quantum dots, we report broadband coupling to the fundamental mode of up $\\beta_{01}=31\\pm2\\%$, in robust agreement with theoretical calculations. Electrospun soft-matter nano...

  14. Dielectric barrier discharge plasma treatment of cellulose nanofibre surfaces

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Madsen, Bo; Berglund, Linn

    2017-01-01

    on the nanofibre surface. Ultrasonic irradiation further enhanced the wetting and oxidation of the nanofibre coating. Scanning electron microscopic observations showed skeleton-like features on the plasma-treated surface, indicating preferential etching of weaker domains, such as low-molecular weight domains......Dielectric barrier discharge plasma treatment was applied to modify cellulose nanofibre (CNF) surfaces with and without ultrasonic irradiation. The plasma treatment improved the wetting by deionised water and glycerol, and increased the contents of oxygen, carbonyl group, and carboxyl group...... and amorphous phases. Ultrasonic irradiation also improved the uniformity of the treatment. Altogether, it is demonstrated that atmospheric pressure plasma treatment is a promising technique to modify the CNF surface before composite processing....

  15. Different Structures of PVA Nanofibrous Membrane for Sound Absorption Application

    Directory of Open Access Journals (Sweden)

    Jana Mohrova

    2012-01-01

    Full Text Available The thin nanofibrous layer has different properties in the field of sound absorption in comparison with porous fibrous material which works on a principle of friction of air particles in contact with walls of pores. In case of the thin nanofibrous layer, which represents a sound absorber here, the energy of sonic waves is absorbed by the principle of membrane resonance. The structure of the membrane can play an important role in the process of converting the sonic energy to a different energy type. The vibration system acts differently depending on the presence of smooth fibers in the structure, amount of partly merged fibers, or structure of polymer foil as extreme. Polyvinyl alcohol (PVA was used as a polymer because of its good water solubility. It is possible to influence the structure of nanofibrous layer during the production process thanks to this property of polyvinyl alcohol.

  16. The photoluminescence properties of zinc oxide nanofibres prepared by electrospinning

    Science.gov (United States)

    Viswanathamurthi, Periasamy; Bhattarai, Narayan; Kim, Hak Yong; Lee, Douk Rae

    2004-03-01

    The morphology and optical properties of zinc oxide fibres with diameters in the nanometre to micrometre range are reported. The PVA/zinc acetate organic/inorganic hybrid nanofibres were successfully prepared by electrospinning using polyvinyl alcohol (PVA) and zinc acetate. Pure zinc oxide fibres were obtained by high-temperature calcination of the hybrid fibres in air. The nanofibres were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), x-ray diffractometry (XRD) and Raman spectroscopy. The photoluminescence spectra under excitation at 325 nm showed an ultraviolet emission at 3.13 eV and a green emission at 2.21 eV. These nanofibres could be used as light emitting devices in nanoscale optoelectronic applications.

  17. Functionalized polymer nanofibre membranes for protection from chemical warfare stimulants

    Energy Technology Data Exchange (ETDEWEB)

    Ramaseshan, Ramakrishnan [Nanoscience and Nanotechnology Initiative, National University of Singapore, 2 Engineering Drive 3, Singapore 117576, Singapore (Singapore); Sundarrajan, Subramanian [Nanoscience and Nanotechnology Initiative, National University of Singapore, 2 Engineering Drive 3, Singapore 117576, Singapore (Singapore); Liu, Yingjun [Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576, Singapore (Singapore); Barhate, R S [Nanoscience and Nanotechnology Initiative, National University of Singapore, 2 Engineering Drive 3, Singapore 117576, Singapore (Singapore); Lala, Neeta L [Nanoscience and Nanotechnology Initiative, National University of Singapore, 2 Engineering Drive 3, Singapore 117576, Singapore (Singapore); Ramakrishna, S [Nanoscience and Nanotechnology Initiative, National University of Singapore, 2 Engineering Drive 3, Singapore 117576, Singapore (Singapore)

    2006-06-28

    A catalyst for the detoxification of nerve agents is synthesized from {beta}-cyclodextrin ({beta}-CD) and o-iodosobenzoic acid (IBA). Functionalized polymer nanofibre membranes from PVC polymer are fabricated with {beta}-CD, IBA, a blend of {beta}-CD+IBA, and the synthesized catalyst. These functionalized nanofibres are then tested for the decontamination of paraoxon, a nerve agent stimulant, and it is observed that the stimulant gets hydrolysed. The kinetics of hydrolysis is investigated using UV spectroscopy. The rates of hydrolysis for different organophosphate hydrolyzing agents are compared. The reactivity and amount of adsorption of these catalysts are of higher capacity than the conventionally used activated charcoal. A new design for protective wear is proposed based on the functionalized nanofibre membrane.

  18. Supporting Privacy Policies in a Publish-Subscribe Substrate for Pervasive Environments

    Directory of Open Access Journals (Sweden)

    Lukasz Opyrchal

    2007-02-01

    Full Text Available A location tracking sensor network is being deployed in several buildings at the University of Michigan to help explore issues in design of pervasive environments. Managing privacy is expected to be a significant concern for acceptance of such pervasive environments. This paper outlines an initial design of a publish-subscribe communication substrate for controlled distribution of sensor data. We describe our prototype as well as a privacy-aware location tracking application built on top of the system. The focus of this paper is on policy management. We provide users with the means to control distribution of data about them (such as their location information through the use of privacy policies. The paper shows how a wide variety of policies can be specified in the system and points out directions for future work.

  19. Comparison of stress, strain, and elastic properties for porous silicon layers supported by substrate and corresponding membranes

    Science.gov (United States)

    Dariani, R. S.; Nazari, M.

    2016-09-01

    This paper describes characterization of mechanical properties of porous silicon (PS) layers with different porosities using high resolution XRD. The XRD measurement determined various mechanical properties of PS such as; Young modulus, Poisson's ratio, and lattice parameter expansion. Our results indicated that mechanical properties reduce with increasing porosity. Also, the mechanical properties of two different porous layers, either supported by or detached from the substrate were examined. Comparison of the two porous layers showed that the constraint in the interatomic spacing is the origin of the lattice constant expansion in the planes perpendicular to the surface. This phenomenon can be useful for gas sensor applications.

  20. Unravelling the enigmatic origin of calcitic nanofibres in soils and caves: purely physicochemical or biogenic processes?

    Directory of Open Access Journals (Sweden)

    S. Bindschedler

    2014-01-01

    Full Text Available Calcitic nanofibres are ubiquitous habits of secondary calcium carbonate (CaCO3 accumulations observed in calcareous vadose environments. Despite their widespread occurrence, the origin of these nanofeatures remains enigmatic. Three possible mechanisms fuel the debate: (i purely physicochemical processes, (ii mineralization of rod-shaped bacteria, and (iii crystal precipitation on organic templates. Nanofibres can be either mineral (calcitic or organic in nature. They are very often observed in association with Needle Fibre Calcite (NFC, another typical secondary CaCO3 habit in terrestrial environments. This association has contributed to some confusion between both habits, however they are truly two distinct calcitic features and their recurrent association is likely to be an important fact to help understanding the origin of nanofibres. In this manuscript the different hypotheses that currently exist to explain the origin of calcitic nanofibres are critically reviewed. In addition to this, a new hypothesis for the origin of nanofibres is proposed based on the fact that current knowledge attributes a fungal origin to NFC. As this feature and nanofibres are recurrently observed together, a possible fungal origin for nanofibres which are associated with NFC is investigated. Sequential enzymatic digestion of the fungal cell wall of selected fungal species demonstrates that the fungal cell wall can be a source of organic nanofibres. The obtained organic nanofibres show a striking morphological resemblance when compared to their natural counterparts, emphasizing a fungal origin for part of the organic nanofibres observed in association with NFC. It is further hypothesized that these organic nanofibres may act as templates for calcite nucleation in a biologically-influenced mineralization process, generating calcitic nanofibres. This highlights the possible involvement of Fungi in CaCO3 biomineralization processes, a role still poorly documented at

  1. Hydrogen storage in graphite nanofibres : new developments

    Energy Technology Data Exchange (ETDEWEB)

    Shutz, W. [Vodafone Pilotentwicklung GmbH, Munich (Germany); Maneck, E. [Bundesanstalt fur Materialforschung, Berlin (Germany)

    2002-07-01

    Carbon materials show high potential as candidates for hydrogen storage for automotive applications, but the price of hydrogen-driven vehicles is too high and customer acceptance is low. In this study, carbon nanofibers were synthesized through the reaction of carbon containing gases over a suitable catalyst. Essentially, carbon nanofibres were created by chemical catalytic vapour deposition of carbon containing gases using a horizontal quartz tube reactor at 500 to 1000 degrees C. The size and shape of the product was found to be dependent on the catalyst used and by the reaction temperature and time. The presentation illustrates gravimetric and volumetric storage capacity measurements, pressure dependent X-ray diffraction and temperature programmed desorption spectroscopy measurements. It was shown that the intercalated hydrogen in carbon nanofibers can be released during heating. Future studies will focus on examining the effects of the interaction between carbon nanofibers and hydrogen with focus on the potential of these materials for technical use in hydrogen storage systems. 7 refs., 2 figs.

  2. Electrospun Polyhydroxybutyrate and Poly(L-lactide-co-ε-caprolactone Composites as Nanofibrous Scaffolds

    Directory of Open Access Journals (Sweden)

    Donraporn Daranarong

    2014-01-01

    Full Text Available Electrospinning can produce nanofibrous scaffolds that mimic the architecture of the extracellular matrix and support cell attachment for tissue engineering applications. In this study, fibrous membranes of polyhydroxybutyrate (PHB with various loadings of poly(L-lactide-co-ε-caprolactone (PLCL were successfully prepared by electrospinning. In comparison to PLCL scaffolds, PLCL blends with PHB exhibited more irregular fibre diameter distributions and higher average fibre diameters but there were no significant differences in pore size. PLCL/PHB scaffolds were more hydrophilic (<120° with significantly reduced tensile strength (ca. 1 MPa compared to PLCL scaffolds (150.9±2.8∘ and 5.8±0.5 MPa. Increasing PLCL loading in PHB/PLCL scaffolds significantly increased the extension at break, (4–6-fold. PLCL/PHB scaffolds supported greater adhesion and proliferation of olfactory ensheathing cells (OECs than those exhibiting asynchronous growth on culture plates. Mitochondrial activity of cells cultivated on the electrospun blended membranes was enhanced compared to those grown on PLCL and PHB scaffolds (212, 179, and 153%, resp.. Analysis showed that PLCL/PHB nanofibrous membranes promoted cell cycle progression and reduced the onset of necrosis. Thus, electrospun PLCL/PHB composites promoted adhesion and proliferation of OECs when compared to their individual PLCL and PHB components suggesting potential in the repair and engineering of nerve tissue.

  3. Nanostructured Multilayer Composite Films of Manganese Dioxide/Nickel/Copper Sulfide Deposited on Polyethylene Terephthalate Supporting Substrate

    Directory of Open Access Journals (Sweden)

    Awangku Nabil Syafiq Bin Awangku Metosen

    2015-01-01

    Full Text Available Nanostructured multilayer manganese dioxide/nickel/copper sulfide (MnO2/Ni/CuS composite films were successfully deposited onto supporting polyethylene terephthalate (PET substrate through the sequential deposition of CuS, Ni, and MnO2 thin films by chemical bath deposition, electrodeposition, and horizontal submersion deposition techniques, respectively. Deposition of each thin-film layer was optimized by varying deposition parameters and conditions associated with specific deposition technique. Both CuS and Ni thin films were optimized for their electrical conductivity whereas MnO2 thin film was optimized for its microstructure and charge capacity. The electrochemical properties of nanostructured multilayer MnO2/Ni/CuS composite films were evaluated by cyclic voltammetry as electrode materials of an electrochemical capacitor prototype in a dual-planar device configuration. Cyclic voltammogram in mild Na2SO4 aqueous electrolyte exhibited a featureless and almost rectangular shape which was indicative of the ideal capacitive behavior and high cycling reversibility of the electrochemical capacitor prototype. Nanostructured multilayer MnO2/Ni/CuS composite films on supporting polyethylene terephthalate (PET substrate could potentially be utilized as electrode materials for the fabrication of high performance electrochemical capacitors.

  4. Tuning the surface structure of nitrogen-doped TiO2 nanofibres--an effective method to enhance photocatalytic activities of visible-light-driven green synthesis and degradation.

    Science.gov (United States)

    Zheng, Zhanfeng; Zhao, Jian; Yuan, Yong; Liu, Hongwei; Yang, Dongjiang; Sarina, Sarina; Zhang, Hongjie; Waclawika, Eric R; Zhu, Huaiyong

    2013-04-26

    Nitrogen-doped TiO2 nanofibres of anatase and TiO2(B) phases were synthesised by a reaction between titanate nanofibres of a layered structure and gaseous NH3 at 400-700 °C, following a different mechanism than that for the direct nitrogen doping from TiO2. The surface of the N-doped TiO2 nanofibres can be tuned by facial calcination in air to remove the surface-bonded N species, whereas the core remains N doped. N-Doped TiO2 nanofibres, only after calcination in air, became effective photocatalysts for the decomposition of sulforhodamine B under visible-light irradiation. The surface-oxidised surface layer was proven to be very effective for organic molecule adsorption, and the activation of oxygen molecules, whereas the remaining N-doped interior of the fibres strongly absorbed visible light, resulting in the generation of electrons and holes. The N-doped nanofibres were also used as supports of gold nanoparticle (Au NP) photocatalysts for visible-light-driven hydroamination of phenylacetylene with aniline. Phenylacetylene was activated on the N-doped surface of the nanofibres and aniline on the Au NPs. The Au NPs adsorbed on N-doped TiO2(B) nanofibres exhibited much better conversion (80 % of phenylacetylene) than when adsorbed on undoped fibres (46 %) at 40 °C and 95 % of the product is the desired imine. The surface N species can prevent the adsorption of O2 that is unfavourable for the hydroamination reaction, and thus, improve the photocatalytic activity. Removal of the surface N species resulted in a sharp decrease of the photocatalytic activity. These photocatalysts are feasible for practical applications, because they can be easily dispersed into solution and separated from a liquid by filtration, sedimentation or centrifugation due to their fibril morphology.

  5. In vivo wound healing and antibacterial performances of electrospun nanofibre membranes.

    Science.gov (United States)

    Liu, Xin; Lin, Tong; Fang, Jian; Yao, Gang; Zhao, Hongqiong; Dodson, Michael; Wang, Xungai

    2010-08-01

    In this work, nanofibre membranes have been produced from polyvinyl alcohol (PVA), polycaprolactone (PCL), polyacrylonitrile (PAN), poly (vinylidene fluoride-co-hexafluoropropene) (PVdF-HFP), and polymer blend of PAN and polyurethane (PEU) using an electrospinning technique, and wound healing performance of the as-spun nanofibre membranes was examined in vivo using female Sprague-Dawley rats. To understand the nutrition effect, a wool protein was coated on PVA and PCL nanofibres and incorporated into PVA nanofibres via coelectrospinning of a PVA solution containing the wool protein. Silver nanoparticles were also applied to PVA nanofibres to improve antibacterial activity. It was found that the wound healing performance is mainly influenced by the porosity, air permeability, and surface wettability of the nanofibre membranes. A nanofibre membrane with good hydrophilicity and high porosity considerably facilitates the healing of wound especially at the early healing stage. However, the fiber diameter and antibacterial activity have little effect on the wound healing efficiency. As pores in nanofibre membranes are typically smaller than that of conventional cotton gauze, the nanofibre membrane should be able to decontaminate and prevent exogenous infections via sieve effect. This work provides basic understanding of material structure-property relationship for further design of efficient nanofibre-based wound dressing materials.

  6. Electrospun poly(lactic acid) based conducting nanofibrous networks

    Energy Technology Data Exchange (ETDEWEB)

    Patra, S N; Bhattacharyya, D [Department of Mechanical Engineering, Centre for Advanced Composite Materials, University of Auckland, Private Bag 92019, Auckland (New Zealand); Ray, S; Easteal, A J, E-mail: d.bhattacharyya@auckland.ac.nz [Department of Chemistry, Centre for Advanced Composite Materials, University of Auckland, Private Bag 92019, Auckland (New Zealand)

    2009-08-15

    Multi-functionalised micro/nanostructures of conducting polymers in neat or blended forms have received much attention because of their unique properties and technological applications in electrical, magnetic and biomedical devices. Biopolymer-based conducting fibrous mats are of special interest for tissue engineering because they not only physically support tissue growth but also are electrically conductive, and thus are able to stimulate specific cell functions or trigger cell responses. They are effective for carrying current in biological environments and can thus be considered for delivering local electrical stimuli at the site of damaged tissue to promote wound healing. Electrospinning is an established way to process polymer solutions or melts into continuous fibres with diameter often in the nanometre range. This process primarily depends on a number of parameters, including the type of polymer, solution viscosity, polarity and surface tension of the solvent, electric field strength and the distance between the spinneret and the collector. The present research has included polyaniline (PANi) as the conducting polymer and poly(L-lactic acid) (PLLA) as the biopolymer. Dodecylbenzene sulphonic acid (DBSA) doped PANi and PLLA have been dissolved in a common solvent (mixtures of chloroform and dimethyl formamide (DMF)), and the solutions successfully electrospun. DMF enhanced the dielectric constant of the solvent, and tetra butyl ammonium bromide (TBAB) was used as an additive to increase the conductivity of the solution. DBSA-doped PANi/PLLA mat exhibits an almost bead-free network of nanofibres that have extraordinarily smooth surface and diameters in the range 75 to 100 nm.

  7. Electrospun poly(lactic acid) based conducting nanofibrous networks

    Science.gov (United States)

    Patra, S. N.; Bhattacharyya, D.; Ray, S.; Easteal, A. J.

    2009-08-01

    Multi-functionalised micro/nanostructures of conducting polymers in neat or blended forms have received much attention because of their unique properties and technological applications in electrical, magnetic and biomedical devices. Biopolymer-based conducting fibrous mats are of special interest for tissue engineering because they not only physically support tissue growth but also are electrically conductive, and thus are able to stimulate specific cell functions or trigger cell responses. They are effective for carrying current in biological environments and can thus be considered for delivering local electrical stimuli at the site of damaged tissue to promote wound healing. Electrospinning is an established way to process polymer solutions or melts into continuous fibres with diameter often in the nanometre range. This process primarily depends on a number of parameters, including the type of polymer, solution viscosity, polarity and surface tension of the solvent, electric field strength and the distance between the spinneret and the collector. The present research has included polyaniline (PANi) as the conducting polymer and poly(L-lactic acid) (PLLA) as the biopolymer. Dodecylbenzene sulphonic acid (DBSA) doped PANi and PLLA have been dissolved in a common solvent (mixtures of chloroform and dimethyl formamide (DMF)), and the solutions successfully electrospun. DMF enhanced the dielectric constant of the solvent, and tetra butyl ammonium bromide (TBAB) was used as an additive to increase the conductivity of the solution. DBSA-doped PANi/PLLA mat exhibits an almost bead-free network of nanofibres that have extraordinarily smooth surface and diameters in the range 75 to 100 nm.

  8. Differences in oxygen reduction catalysis of platinised acid treated Showa Denko carbon nanofibres

    DEFF Research Database (Denmark)

    Veltzé, Sune; Yli-Rantala, Elina; Borghei, Maryam;

    2011-01-01

    forms of the ECSA degradation: By agglomeration of the platinum crystallites, Rietveld ripening or indirectly by corrosion of the carbon support. Graphitised carbon nanostructures like carbon nanotubes (CNTs), carbon nanofibres (CNFs), etc. are proposed as carbon support substitutes to avoid carbon......The use of carbon as support material for platinum nano-crystallites in polymer electrolyte fuel cells (PEFC) is a common method for increasing the electrochemical specific surface area (ECSA) of platinum. During fuel cell operation, the conditions that catalysts are subjected to lead to various...... corrosion, as the nanostructures are thermally and chemically more durable. The presented work describes the effects on surface defect of acid treated Showa Denko vapour grown carbon fibres (VGCF®/VGCF-H®). A selection of carbon fibres have been platinised and the differences of the oxygen reduction...

  9. Fabrication of three-dimensional nanofibrous macrostructures by electrospinning

    Directory of Open Access Journals (Sweden)

    Ping Zhu

    2016-05-01

    Full Text Available Electrospinning has been widely used in fabricating nanofibers and nanofibrous membranes. Recently, the fabrication of three-dimensional (3D nanofibrous macrostructures has become a hot subject in the development of electrospinning technology. In this paper, the 3D nanofibrous macrostructure was constructed by using electrospinning apparatus with both dynamic and static 3D collecting templates. The effect of the governing parameters on the formation process of 3D macrostructure is studied, such as the applied voltage, the flow rate, the needle-tip-to-collector distance, and the rotating speed. It was found that laying the collecting device either in parallel or perpendicularly with some gap in between, would lead to orderly deposition of nanofibers. In this study, a “dumbbell” dynamic collector was used to fabricate special 3D macrostructures consisting of multilayers of fibrous membranes. By adjusting the rotating speed of the collector, the formation process of multilayer 3D macrostructure can be controlled. An umbrella-shaped static structure collector was used to fabricate 3D framework structures. It is feasible to fabricate various 3D nanofibrous structures via electrospinning with 3D collecting templates, which has great potential in tissue engineering.

  10. Fabrication of nanofibrous scaffolds for tissue engineering applications

    NARCIS (Netherlands)

    Chen, H.; Truckenmuller, R.K.; Blitterswijk, van C.A.; Moroni, L.; Gaharwar, A.K.; Sant, S.; Hancock, M.J.; Hacking, A.A.

    2013-01-01

    Nanofibrous scaffolds which mimic the structural features of a natural extracellular matrix (ECM) can be appealing scaffold candidates for tissue engineering as they provide similar physical cues to the native environment of the targeted tissue to regenerate. This chapter discusses different strateg

  11. Novel compaction resistant and ductile nanocomposite nanofibrous microfiltration membranes.

    Science.gov (United States)

    Homaeigohar, Seyed Shahin; Elbahri, Mady

    2012-04-15

    Despite promising filtration abilities, low mechanical properties of extraordinary porous electrospun nanofibrous membranes could be a major challenge in their industrial development. In addition, such kind of membranes are usually hydrophobic and non-wettable. To reinforce an electrospun nanofibrous membrane made of polyethersulfone (PES) mechanically and chemically (to improve wettability), zirconia nanoparticles as a novel nanofiller in membrane technology were added to the nanofibers. The compressive and tensile results obtained through nanoindentation and tensile tests, respectively, implied an optimum mechanical properties after incorporation of zirconia nanoparticles. Especially compaction resistance of the electrospun nanofibrous membranes improved significantly as long as no agglomeration of the nanoparticles occurred and the electrospun nanocomposite membranes showed a higher tensile properties without any brittleness i.e. a high ductility. Noteworthy, for the first time the compaction level was quantified through a nanoindentation test. In addition to obtaining a desired mechanical performance, the hydrophobicity declined. Combination of promising properties of optimum mechanical and surface chemical properties led to a considerably high water permeability also retention efficiency of the nanocomposite PES nanofibrous membranes. Such finding implies a longer life span and lower energy consumption for a water filtration process.

  12. Nanofiltration membranes based on polyvinylidene fluoride nanofibrous scaffolds and crosslinked polyethyleneimine networks

    Science.gov (United States)

    Park, Seong-Jik; Cheedrala, Ravi Kumar; Diallo, Mamadou S.; Kim, Changmin; Kim, In S.; Goddard, William A.

    2012-07-01

    In this article, we describe the synthesis of new and ion-selective nanofiltration (NF) membranes using polyvinylidene fluoride (PVDF) nanofibers and hyperbranched polyethylenimine (PEI) as building blocks. These new nanofibrous composite (NFC) membranes consist of crosslinked hyperbranched PEI networks supported by PVDF nanofibrous scaffolds that are electrospun onto commercial PVDF microfiltration (MF) membranes. A major objective of our study was to fabricate positively charged NF membranes that can be operated at low pressure with high water flux and improved rejection for monovalent cations. To achieve this, we investigated the effects of crosslinker chemistry on membrane properties (morphology, composition, hydrophobicity, and zeta potential) and membrane performance (salt rejection and permeate flux) in aqueous solutions (2,000 mg/L) of four salts (NaCl, MgCl2, Na2SO4, and MgSO4) at pH 4, 6, and 8. We found that an NFC-PVDF membrane with a network of PEI macromolecules crosslinked with trimesoyl chloride has a high water flux ( 30 L m-2 h-1) and high rejections for MgCl2 ( 88 %) and NaCl ( 65 %) at pH 6 using a pressure of 7 bar. The overall results of our study suggest that PVDF nanofibers and hyperbranched PEI are promising building blocks for the fabrication of high performance NF membranes for water purification.

  13. Nanofiltration membranes based on polyvinylidene fluoride nanofibrous scaffolds and crosslinked polyethyleneimine networks

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seong-Jik [Hankyong National University, Department of Bioresources and Rural Systems Engineering (Korea, Republic of); Cheedrala, Ravi Kumar; Diallo, Mamadou S., E-mail: mdiallo@kaist.ac.kr [Korea Advanced Institute of Science and Technology (KAIST), Graduate School of Energy, Environment, Water and Sustainability (EEWS) (Korea, Republic of); Kim, Changmin; Kim, In S. [Gwangju Institute of Science and Technology (GIST), Department of Environmental Science and Engineering (Korea, Republic of); Goddard, William A. [Korea Advanced Institute of Science and Technology (KAIST), Graduate School of Energy, Environment, Water and Sustainability (EEWS) (Korea, Republic of)

    2012-07-15

    In this article, we describe the synthesis of new and ion-selective nanofiltration (NF) membranes using polyvinylidene fluoride (PVDF) nanofibers and hyperbranched polyethylenimine (PEI) as building blocks. These new nanofibrous composite (NFC) membranes consist of crosslinked hyperbranched PEI networks supported by PVDF nanofibrous scaffolds that are electrospun onto commercial PVDF microfiltration (MF) membranes. A major objective of our study was to fabricate positively charged NF membranes that can be operated at low pressure with high water flux and improved rejection for monovalent cations. To achieve this, we investigated the effects of crosslinker chemistry on membrane properties (morphology, composition, hydrophobicity, and zeta potential) and membrane performance (salt rejection and permeate flux) in aqueous solutions (2,000 mg/L) of four salts (NaCl, MgCl{sub 2}, Na{sub 2}SO{sub 4}, and MgSO{sub 4}) at pH 4, 6, and 8. We found that an NFC-PVDF membrane with a network of PEI macromolecules crosslinked with trimesoyl chloride has a high water flux ({approx}30 L m{sup -2} h{sup -1}) and high rejections for MgCl{sub 2} ({approx}88 %) and NaCl ({approx}65 %) at pH 6 using a pressure of 7 bar. The overall results of our study suggest that PVDF nanofibers and hyperbranched PEI are promising building blocks for the fabrication of high performance NF membranes for water purification.

  14. Cuttlebone-like V2O5 Nanofibre Scaffolds – Advances in Structuring Cellular Solids

    Science.gov (United States)

    Knöller, Andrea; Runčevski, Tomče; Dinnebier, Robert E.; Bill, Joachim; Burghard, Zaklina

    2017-02-01

    The synthesis of ceramic materials combining high porosity and permeability with good mechanical stability is challenging, as optimising the latter requires compromises regarding the first two properties. Nonetheless, significant progress can be made in this direction by taking advantage of the structural design principles evolved by nature. Natural cellular solids achieve good mechanical stability via a defined hierarchical organisation of the building blocks they are composed of. Here, we report the first synthetic, ceramic-based scaffold whose architecture closely mimics that of cuttlebone –a structural biomaterial whose porosity exceeds that of most other natural cellular solids, whilst preserving an excellent mechanical strength. The nanostructured, single-component scaffold, obtained by ice-templated assembly of V2O5 nanofibres, features a highly sophisticated and elaborate architecture of equally spaced lamellas, which are regularly connected by pillars as lamella support. It displays an unprecedented porosity of 99.8 %, complemented by an enhanced mechanical stability. This novel bioinspired, functional material not only displays mechanical characteristics similar to natural cuttlebone, but the multifunctionality of the V2O5 nanofibres also renders possible applications, including catalysts, sensors and electrodes for energy storage.

  15. Enhancing trimethylolpropane esters synthesis through lipase immobilized on surface hydrophobic modified support and appropriate substrate feeding methods.

    Science.gov (United States)

    Tao, Yifeng; Cui, Caixia; Shen, Huaqing; Liu, Luo; Chen, Biqiang; Tan, Tianwei

    2014-05-10

    Candida sp. 99-125 lipase immobilized on surface hydrophobic modified support and appropriate substrate feeding methods were used to improve the synthesis of tri-substituted trimethylolpropane (TMP) esters, which can be used as raw materials for biodegradable lubricants. The proposed novel production method is environmentally friendly. Lipase was adsorbed on surface hydrophobic silk fibers that were pretreated by amino-modified polydimethylsiloxane. A 5-level-4-factors central composite model, including reaction time, temperature, enzyme amount, and molar ratio of fatty acid to TMP, was designed to evaluate the interaction of process variables in the enzymatic esterification. The water activity was kept constant using a LiCl-saturated salt solution. Under the optimum conditions with 30% enzyme amount and substrates molar ratio 8.4 at 45°C for 47h, the total conversion of caprylic acid is 97.3% and the yield of tri-substituted TMP esters is 95.5%. The surface hydrophobic treatment resulted in less cluster water accumulated on the surface immobilized lipase, which was demonstrated by near-infrared spectra. Consequently, the optimum temperature and water tolerance of immobilized lipase were increased. Two TMP-feeding methods were used to maintain high molar ratio of fatty acid to TMP, and increase the final tri-substituted TMP esters content exceeding 85% (w/w) in reactant.

  16. Neutron reflectivity study of substrate surface chemistry effects on supported phospholipid bilayer formation on (1120) sapphire.

    Energy Technology Data Exchange (ETDEWEB)

    Oleson, Timothy A. [University of Wisconsin, Madison; Sahai, Nita [University of Akron; Wesolowski, David J [ORNL; Dura, Joseph A [ORNL; Majkrzak, Charles F [ORNL; Giuffre, Anthony J. [University of Wisconsin, Madison

    2012-01-01

    Oxide-supported phospholipid bilayers (SPBs) used as biomimetric membranes are significant for a broad range of applications including improvement of biomedical devices and biosensors, and in understanding biomineralization processes and the possible role of mineral surfaces in the evolution of pre-biotic membranes. Continuous-coverage and/or stacjed SPBs retain properties (e.,g. fluidity) more similar to native biological membranes, which is desirable for most applications. Using neutron reflectivity, we examined face coverage and potential stacking of dipalmitoylphosphatidylcholine (DPPC) bilayers on the (1120) face of sapphire (a-Al2O3). Nearly full bilayers were formed at low to neutral pH, when the sapphire surface is positively charged, and at low ionic strength (l=15 mM NaCl). Coverage decreased at higher pH, close to the isoelectric point of sapphire, and also at high I>210mM, or with addition of 2mM Ca2+. The latter two effects are additive, suggesting that Ca2+ mitigates the effect of higher I. These trends agree with previous results for phospholipid adsorption on a-Al2O3 particles determined by adsorption isotherms and on single-crystal (1010) sapphire by atomic force microscopy, suggesting consistency of oxide surface chemistry-dependent effects across experimental techniques.

  17. Adsorption of silver ions on polypyrrole embedded electrospun nanofibrous polyethersulfone membranes.

    Science.gov (United States)

    Wu, Jiunn-Jong; Lee, Hsiu-Wen; You, Jiann-Hwa; Kau, Yi-Chuan; Liu, Shih-Jung

    2014-04-15

    In this study we developed polypyrrole embedded electrospun nanofibrous polyethersulfone nanofibrous membranes for the removal of silver ions. Polypyrrole and polyethersulfone dissolved in N-methyl-2-pyrrolidone (NMP) were electrospun into nanofibrous membranes via an electrospinning process. The morphology of as-spun polypyrrole/polyethersulfone nanofibers was examined by scanning electron microscopy. The average diameter of electrospun nanofibers ranged from 410 nm to 540 nm. The adsorption capability of nanofibrous polypyrrole/polyethersulfone membranes was measured and compared with that of bulk polypyrrole. The influence of various process conditions on adsorption efficiency was also examined. The experimental results suggested that the electrospun nanofibrous membranes exhibited good silver ion uptake capabilities. The metal uptake of nanofibrous membranes increased with the initial metal ion concentrations and the pH value, while decreased with the temperature and the filtering rate of the solutions. Furthermore, the electrospun membrane could be reused after the recovery process. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Glutaraldehyde vapor cross-linked nanofibrous PVA mat with in situ formed silver nanoparticles.

    Science.gov (United States)

    Destaye, Addisu Getachew; Lin, Cheng-Keng; Lee, Cheng-Kang

    2013-06-12

    Polyvinyl alcohol (PVA) nanofibrous mat can be easily prepared via electrospinning its aqueous solution. However, the obtained nanofibrous mat is instantaneously dissolved in water. Therefore, rendering the environmentally friendly nanofibrous mat water insoluble by cross-linking mechanism is of great interest. The electrospun PVA nanofibrous mat with an average fiber diameter of ca. 400 nm could be effectively cross-linked by glutaraldehyde vapor at room temperature. The cross-linking not only resulted in a water-insoluble nanofibrous mat but also generated an excess amount of unreacted aldehyde functional groups that could reduce silver salts into silver nanoparticles. The in situ formed silver nanoparticles along the fibrous surface showed excellent antimicrobial activity against Escherichia coli. The vapor cross-linked nanofibrous mat shows a high potential to be used for efficiently capturing and killing pathogenic bacteria.

  19. Bamboo and herringbone shaped carbon nanotubes and carbon nanofibres synthesized in direct current-plasma enhanced chemical vapour deposition.

    Science.gov (United States)

    Zhang, Lu; Chen, Li; Wells, Torquil; El-Gomati, Mohamed

    2009-07-01

    Carbon nanotubes with different structures were catalytically synthesized on Ni coated SiO2/Si substrate in a Direct Current Plasma Enhanced Chemical Vapour Deposition system, in which C2H2 acted as the carbon source and NH3 as the etchant gas. A Scanning Electron Microscope study showed that carbon nanotubes were all vertically aligned with respect to the substrate, with diameters ranging from 10 nm to 200 nm. Different sizes of Ni catalyst particles were observed on the tips of carbon nanotubes. Transmission Electron Microscopy was used to study the morphology of the grown tubes and the results obtained show that the diameters and structures of these carbon nanotubes were closely correlated to the sizes and structures of the Ni nanoparticles. Two main structures namely bamboo shaped carbon nanotubes and herringbone shaped carbon nanofibres were found on the same sample. It is suggested that by controlling the pre-growth condition, desired structure of carbon nanotubes or carbon nanofibres could be produced for practical applications.

  20. Preparation and characterization of polysaccharides/PVA blend nanofibrous membranes by electrospinning method

    OpenAIRE

    2014-01-01

    A series of polyvinyl alcohol (PVA), PVA/chitosan (CS) and PVA/cyanobacterial extracellular polymeric substances (EPS) blended nanofibrous membranes were produced by electrospinning using a microfiltration poly(vinylidene fluoride) (PVDF) basal membrane, for potential applications in water filtration. Nanofibres were obtained from solutions of 20% (w/w) PVA with 1% (w/w) CS or EPS, using a weight ratio of 60/40. Blended nanofibres have shown a smooth morphology, no beads formation and diamete...

  1. Novel PVA/MOF Nanofibres: Fabrication, Evaluation and Adsorption of Lead Ions from Aqueous Solution

    OpenAIRE

    2016-01-01

    Plain polyvinyl alcohol (PVA) nanofibres and novel polyvinyl alcohol benzene tetracarboxylate nanofibres incorporated with strontium, lanthanum and antimony ((PVA/Sr-TBC), (PVA/La-TBC) and (PVA/Sb-TBC)), respectively, where TBC is benzene 1,2,4,5-tetracarboxylate adsorbents, were fabricated by electrospinning. The as-prepared electrospun nanofibres were characterized by scanning electron microscope (SEM), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA). Only plain PVA n...

  2. Cellulose acetate electrospun nanofibrous membrane: fabrication, characterization, drug loading and antibacterial properties

    Indian Academy of Sciences (India)

    NAZNIN SULTANA; ANISAH ZAINAL

    2016-04-01

    Cellulose-based materials are one of the most commonly used materials for biomedical applications, which normally applied as carriers for pharmaceuticals and drug-releasing scaffolds. In this study, cellulose acetate (CA) was used to fabricate the nanofibrous membrane using the electrospinning technique. CA solutions at different concentrations were prepared by dissolving the polymer in a mixture of acetic acid/acetone solvents with the ratio of 3:1. The field emission scanning electron microscope results showed that electrospinning of 10% (w/v) CA produced nanofibres with many beads. When the CA concentration was increased to 14% (w/v), bead-free nanofibres were produced. The contact angle measurement results confirmed the hydrophilic properties of nanofibres. In order to prevent common bacterial infections, a model drug, Tetracycline · HCL was incorporated into the CA nanofibres. The drug-loaded CA nanofibres showed antibacterial activity against Gram-positive and Gram-negative bacteria.CA nanofibres had high water uptake properties. The CA nanofibrous membrane was non-toxic to human skin fibroblast cells. Thus the CA nanofibres with 14% (w/v) concentration exerted suitable properties for wound healingapplication.

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

    Science.gov (United States)

    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.

  4. Structural and Photoluminescence Properties of β-Ga2O3 Nanofibres Fabricated by Electrospinning Method

    Institute of Scientific and Technical Information of China (English)

    ZHAO Jian-Guo; ZHANG Zhen-Xing; MA Zi-Wei; DUAN Hui-Gao; GUO Xiao-Song; XIE Er-Qing

    2008-01-01

    We have prepared the β-Ga2Oa nanofibres by electrospinning method followed by calcining in air at 900℃. The morphology and structure of the nanofibres are characterized by field emission scanning electron microscopy(FE-SEM), x-ray diffraction (XRD) and Raman technique. These nanofibres have diameters ranging from 60 to 13Onm and lengths up to several millimetres. Photoluminescence (PL) spectrum under excitation at 325nm shows that these β-Ga2Oa nanofibres have a blue emission peaking at 466nm, which may be attributed to defects such as the oxygen vacancies, gallium vacancies and gallium-oxygen vacancy pairs.

  5. Surface Modification of Electrospun PVDF/PAN Nanofibrous Layers by Low Vacuum Plasma Treatment

    Directory of Open Access Journals (Sweden)

    Fatma Yalcinkaya

    2016-01-01

    Full Text Available Nanofibres are very promising for water remediation due to their high porosity and small pore size. Mechanical properties of nanofibres restrict the application of pressure needed water treatments. Various PAN, PVDF, and PVDF/PAN nanofibre layers were produced, and mechanical properties were improved via a lamination process. Low vacuum plasma treatment was applied for the surface modification of nanofibres. Atmospheric air was used to improve hydrophilicity while sulphur hexafluoride gas was used to improve hydrophobicity of membranes. Hydrophilic membranes showed higher affinity to attach plasma particles compared to hydrophobic membranes.

  6. Thickness, stability and contact angle of liquid films on and inside nanofibres, nanotubes and nanochannels.

    Science.gov (United States)

    Mattia, Davide; Starov, Victor; Semenov, Sergey

    2012-10-15

    While the stability of liquid films on substrates is a classical topic of colloidal science, the availability of nanostructured materials, such as nanotubes, nanofibres and nanochannels, has raised the question of how the stability of liquid films and their wetting behaviour is affected by nanoscale confinement. This paper will present the conditions for the stability of liquid films on and inside cylindrical solid substrates with nanometre scale characteristic dimensions. It is shown that the stability is determined by an effective disjoining/conjoining pressure isotherm which differs from the corresponding disjoining/conjoining pressure isotherm of flat liquid films on flat solid substrates. From the former, the equilibrium contact angles of drops on an outer or inner surface of a cylindrical capillary have been calculated as a function of surface curvature, showing that the expressions for equilibrium contact angles vary for different geometries, in view of the difference in thickness of the film of uniform thickness with which the bulk liquid (drops or menisci) is at equilibrium. These calculations have been extended to the case of glass nanocapillaries and carbon nanotubes, finding good agreement with experimental results in the literature.

  7. A conceptual configuration of the lunar base bioregenerative life support system including soil-like substrate for growing plants

    Science.gov (United States)

    Liu, H.; Yu, C. Y.; Manukovsky, N. S.; Kovalev, V. S.; Gurevich, Yu L.; Wang, J.

    2008-09-01

    The paper presents a conceptual configuration of the lunar base bioregenerative life support system (LBLSS), including soil-like substrate (SLS) for growing plants. SLS makes it possible to combine the processes of plant growth and the utilization of plant waste. Plants are to be grown on SLS on the basis of 20 kg of dry SLS mass or 100 kg of wet SLS mass per square meter. The substrate is to be delivered to the base ready-made as part of the plant growth subsystem. Food for the crew was provided by prestored stock 24% and by plant growing system 76%. Total dry weight of the food is 631 g per day (2800 kcal/day) for one crew member (CM). The list of candidate plants to be grown under lunar BLSS conditions included 14 species: wheat, rice, soybean, peanuts, sweet pepper, carrots, tomatoes, coriander, cole, lettuce, radish, squash, onion and garlic. From the prestored stock the crew consumed canned fish, iodinated salt, sugar, beef sauce and seafood sauce. Our calculations show that to provide one CM with plant food requires the area of 47.5 m 2. The balance of substance is achieved by the removal dehydrated urine 59 g, feces 31 g, food waste 50 g, SLS 134 g, and also waters 86 g from system and introduction food 236 g, liquid potassium soap 4 g and mineral salts 120 g into system daily. To reduce system setup time the first plants could be sowed and germinated to a certain age on the Earth.

  8. Testing anti-fungal activity of a soil-like substrate for growing plants in bioregenerative life support systems

    Science.gov (United States)

    Nesterenko, E. V.; Kozlov, V. A.; Khizhnyak, S. V.; Manukovsky, N. S.; Kovalev, V. S.; Gurevich, Yu. L.; Liu, Hong; Xing, Yidong; Hu, Enzhu

    2009-10-01

    The object of this research is to study a soil-like substrate (SLS) to grow plants in a Bioregenerative Life Support System (BLSS). Wheat and rice straw were used as raw materials to prepare SLS. Anti-fungal activity of SLS using test cultures of Bipolaris sorokiniana, a plant-pathogenic fungus which causes wheat root rot was studied. Experiments were conducted with SLS samples, using natural soil and sand as controls. Infecting the substrates, was performed at two levels: the first level was done with wheat seeds carrying B. sorokiniana and the second level with seeds and additional conidia of B. sorokiniana from an outside source. We measured wheat disease incidence and severity in two crop plantings. Lowest disease incidence values were obtained from the second planting, SLS: 26% and 41% at the first and the second infection levels, respectively. For soil the values were 60% and 82%, respectively, and for sand they were 67% and 74%, respectively. Wheat root rot in the second crop planting on SLS, at both infection levels was considerably less severe (9% and 13%, respectively) than on natural soil (20% and 33%) and sand (22% and 32%). SLS significantly suppressed the germination of B. sorokiniana conidia. Conidia germination was 5% in aqueous SLS suspension, and 18% in clean water. No significant differences were found regarding the impact on conidia germination between the SLS samples obtained from wheat and rice straw. The anti-fungal activity in SLS increased because of the presence of worms. SLS also contained bacteria stimulating and inhibiting B. sorokiniana growth.

  9. NANOFIBROUS MATS WITH BIRD'S NEST PATTERNS BY ELECTROSPINNING

    Institute of Scientific and Technical Information of China (English)

    Xiang-yu Ye; Xiao-jun Huang; Zhi-kang Xu

    2012-01-01

    Electrospun material with bio-inspired ordered architectures and patterns is very interesting,yet remains a challenge.We report here that nanofibrous mats with bird's nest patterned structures can be directly electrospun from chlorinated polypropylene solutions doped with an ionic liquid.The solution viscosity and the ionic liquid content are two dominant factors to influence the lopological morphology of the nanofibrous mats.The patterned structures can be further modulated by the collection time of electrospinning,the humidity of environment and the design of collector.We suggest the electrostatic repulsion between the residual charges of the mat surface and the upcoming nanofibers plays a key role in the formation of the bird's nest patterns.

  10. Emerging chitin and chitosan nanofibrous materials for biomedical applications

    Science.gov (United States)

    Ding, Fuyuan; Deng, Hongbing; Du, Yumin; Shi, Xiaowen; Wang, Qun

    2014-07-01

    Over the past several decades, we have witnessed significant progress in chitosan and chitin based nanostructured materials. The nanofibers from chitin and chitosan with appealing physical and biological features have attracted intense attention due to their excellent biological properties related to biodegradability, biocompatibility, antibacterial activity, low immunogenicity and wound healing capacity. Various methods, such as electrospinning, self-assembly, phase separation, mechanical treatment, printing, ultrasonication and chemical treatment were employed to prepare chitin and chitosan nanofibers. These nanofibrous materials have tremendous potential to be used as drug delivery systems, tissue engineering scaffolds, wound dressing materials, antimicrobial agents, and biosensors. This review article discusses the most recent progress in the preparation and application of chitin and chitosan based nanofibrous materials in biomedical fields.

  11. Fabrication of electrospun nanofibrous membranes for membrane distillation application

    KAUST Repository

    Francis, Lijo

    2013-02-01

    Nanofibrous membranes of Matrimid have been successfully fabricated using an electrospinning technique under optimized conditions. Nanofibrous membranes are found to be highly hydrophobic with a high water contact angle of 130°. Field emission scanning electron microscopy and pore size distribution analysis revealed the big pore size structure of electrospun membranes to be greater than 2 μm and the pore size distribution is found to be narrow. Flat sheet Matrimid membranes were fabricated via casting followed by phase inversion. The morphology, pore size distribution, and water contact angle were measured and compared with the electrospun membranes. Both membranes fabricated by electrospinning and phase inversion techniques were tested in a direct contact membrane distillation process. Electrospun membranes showed high water vapor flux of 56 kg/m2-h, which is very high compared to the casted membrane as well as most of the fabricated and commercially available highly hydrophobic membranes. ©2013 Desalination Publications.

  12. Fabrication of a biomimetic ZeinPDA nanofibrous scaffold impregnated with BMP-2 peptide conjugated TiO2 nanoparticle for bone tissue engineering.

    Science.gov (United States)

    Sekar, Babitha; Annamalai, Meenakshi; Dykas, Michal Marcin; Saha, Surajit; Poddar, Kingshuk; Venugopal, Jayarama Reddy; Ramakrishna, Seeram; Venkatesan, Thirumalai; Korrapati, Purna Sai

    2017-09-04

    A biomimetic Zein polydopamine (PDA) based nanofiber scaffold was fabricated to deliver bone morphogenic protein-2 (BMP-2) peptide conjugated titanium dioxide (TiO2 ) nanoparticles in a sustained manner for investigating its osteogenic differentiation potential. To prolong its retention time at the target site, BMP-2 peptide has been conjugated to TiO2 nanoparticles owing to its high surface to volume ratio. The effect of biochemical cues from BMP-2 peptide and nano topographical stimulation of electrospun Zein PDA nanofibers were examined for its enhanced osteogenic expression of human fetal osteoblast (hFOB) cells. The sustained delivery of bioactive signals, improved cell adhesion, mineralization and differentiation could be attributed to its highly interconnected nanofibrous matrix with unique material composition. Further, the expression of osteogenic markers revealed that the fabricated nanofibrous scaffold possess better cell - biomaterial interactions. These promising results demonstrate the potential of the composite nanofibrous scaffold as an effective biomaterial substrate for bone regeneration. This article is protected by copyright. All rights reserved.

  13. Hemocompatible surface of electrospun nanofibrous scaffolds by ATRP modification

    Energy Technology Data Exchange (ETDEWEB)

    Yuan, Wenjie [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Feng, Yakai, E-mail: yakaifeng@hotmail.com [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Key Laboratory of Systems Bioengineering of Ministry of Education, Tianjin University, Tianjin 300072 (China); Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Weijin Road 92, 300072 Tianjin (China); Wang, Heyun [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832002 (China); Yang, Dazhi [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); An, Bo [Department of Orthopedics, Affiliated Hospital of Logistics University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Zhang, Wencheng [Department of Physiology and Pathophysiology, Logistics University of Chinese People' s Armed Police Force, Tianjin 300162 (China); Khan, Musammir [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Guo, Jintang [School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072 (China); Tianjin University-Helmholtz-Zentrum Geesthacht, Joint Laboratory for Biomaterials and Regenerative Medicine, Weijin Road 92, 300072 Tianjin (China)

    2013-10-15

    The electrospun scaffolds are potential application in vascular tissue engineering since they can mimic the nano-sized dimension of natural extracellular matrix (ECM). We prepared a fibrous scaffold from polycarbonateurethane (PCU) by electrospinning technology. In order to improve the hydrophilicity and hemocompatibility of the fibrous scaffold, poly(ethylene glycol) methacrylate (PEGMA) was grafted onto the fiber surface by surface-initiated atom transfer radical polymerization (SI-ATRP) method. Although SI-ATRP has been developed and used for surface modification for many years, there are only few studies about the modification of electrospun fiber by this method. The modified fibrous scaffolds were characterized by SEM, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). The scaffold morphology showed no significant difference when PEGMA was grafted onto the scaffold surface. Based on the water contact angle measurement, the surface hydrophilicity of the scaffold surface was improved significantly after grafting hydrophilic PEGMA (P = 0.0012). The modified surface showed effective resistance for platelet adhesion compared with the unmodified surface. Activated partial thromboplastin time (APTT) of the PCU-g-PEGMA scaffold was much longer than that of the unmodified PCU scaffold. The cyto-compatibility of electrospun nanofibrous scaffolds was tested by human umbilical vein endothelial cells (HUVECs). The images of 7-day cultured cells on the scaffold surface were observed by SEM. The modified scaffolds showed high tendency to induce cell adhesion. Moreover, the cells reached out pseudopodia along the fibrous direction and formed a continuous monolayer. Hemolysis test showed that the grafted chains of PEGMA reduced blood coagulation. These results indicated that the modified electrospun nanofibrous scaffolds were potential application as artificial blood vessels. Highlights: • Electrospun nanofibrous scaffolds were successfully

  14. Fabrication and Application of Nanofibrous Scaffolds in Tissue Engineering

    OpenAIRE

    Li, Wan-Ju; Tuan, Rocky S

    2009-01-01

    Nanofibers fabricated by electrospinning are morphological mimics of fibrous components of the native extracellular matrix, making nanofibrous scaffolds ideal for three-dimensional cell culture and tissue engineering applications. Although electrospinning is not a conventional technique in cell biology, the experimental set-up may be constructed in a relatively straightforward manner and the procedure can be carried by individuals with limited engineering experience. We detail here a protocol...

  15. Compression of the DNA substrate by a viral packaging motor is supported by removal of intercalating dye during translocation.

    Science.gov (United States)

    Dixit, Aparna Banerjee; Ray, Krishanu; Black, Lindsay W

    2012-12-11

    Viral genome packaging into capsids is powered by high-force-generating motor proteins. In the presence of all packaging components, ATP-powered translocation in vitro expels all detectable tightly bound YOYO-1 dye from packaged short dsDNA substrates and removes all aminoacridine dye from packaged genomic DNA in vivo. In contrast, in the absence of packaging, the purified T4 packaging ATPase alone can only remove up to ∼1/3 of DNA-bound intercalating YOYO-1 dye molecules in the presence of ATP or ATP-γ-S. In sufficient concentration, intercalating dyes arrest packaging, but rare terminase mutations confer resistance. These distant mutations are highly interdependent in acquiring function and resistance and likely mark motor contact points with the translocating DNA. In stalled Y-DNAs, FRET has shown a decrease in distance from the phage T4 terminase C terminus to portal consistent with a linear motor, and in the Y-stem DNA compression between closely positioned dye pairs. Taken together with prior FRET studies of conformational changes in stalled Y-DNAs, removal of intercalating compounds by the packaging motor demonstrates conformational change in DNA during normal translocation at low packaging resistance and supports a proposed linear "DNA crunching" or torsional compression motor mechanism involving a transient grip-and-release structural change in B form DNA.

  16. Functionalization of Carbon Nanofibres Obtained by Floating Catalyst Method

    Directory of Open Access Journals (Sweden)

    Adolfo Fernández

    2015-01-01

    Full Text Available The excellent physicochemical and electrical properties of carbon nanofibres (CNF combined with the possibility of being produced at industrial scale at reasonable costs have promoted the interest in their use in very diverse areas. However, there are still some drawbacks that must be solved in order to optimize their set of properties such as the presence of impurities or the imperfections in the crystalline structure. In this work, different modification treatments of CNFs produced by the floating catalyst method have been studied. Three types of modification processes have been explored that can be grouped as mechanical, thermal, and chemical functionalization processes. Mechanical processing has allowed solving the agglomeration problem related to CNFs produced by floating catalyst method and the resulting modified product ensures the secure handling of carbon nanofibres. Thermal and chemical treatments lead to purer and more crystalline products by removing catalyst impurities and amorphous carbon. Functionalization processes explored in this work open the possibility of customized posttreatment of carbon nanofibres according to the desired requirements.

  17. Superamphiphobic nanofibrous membranes for effective filtration of fine particles.

    Science.gov (United States)

    Wang, Na; Zhu, Zhigao; Sheng, Junlu; Al-Deyab, Salem S; Yu, Jianyong; Ding, Bin

    2014-08-15

    The worldwide demands are rising for an energy-efficient and cost-effective approach that can provide advanced nanofibrous membranes with high filtration performance and superior antifouling properties. Here we report a novel synthesized fluorinated polyurethane (FPU) modified nanofibrous membrane optimized to achieve oil and non-oil aerosol particle filtration. By employing the FPU incorporation, the polyacrylonitrile/polyurethane (PAN/PU) composite membranes were endowed with superhydrophobicity with a water contact angle of 154° and superoleophobicity with an oil contact angle of 151°. Morphology, surface wettability, porous structure, and filtration performance could be manipulated by tuning the solution composition as well as the hierarchical structure. Furthermore, the as-prepared membranes can capture, for the first time, a range of different oil aerosol particles in a single-unit operation, with >99.9% filtration efficiency, by using the combined contribution of fiber diameter and surface roughness acting on the objective particles. Exemplified here by the construction of superamphiphobic nanofibrous membrane, numerous applications of this medium includes high efficiency particulate air filters, ultra-low penetration air filters, and respiratory protection equipment.

  18. Composite poly-L-lactic acid/poly-({alpha},{beta})-DL-aspartic acid/collagen nanofibrous scaffolds for dermal tissue regeneration

    Energy Technology Data Exchange (ETDEWEB)

    Ravichandran, Rajeswari [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Department of Mechanical Engineering, National University of Singapore, 117576 (Singapore); Venugopal, Jayarama Reddy, E-mail: nnijrv@nus.edu.sg [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Sundarrajan, Subramanian [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Department of Mechanical Engineering, National University of Singapore, 117576 (Singapore); Mukherjee, Shayanti [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Sridhar, Radhakrishnan [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Department of Mechanical Engineering, National University of Singapore, 117576 (Singapore); Ramakrishna, Seeram, E-mail: seeram@nus.edu.sg [Healthcare and Energy Materials Laboratory, Nanoscience and Nanotechnology Initiative, Faculty of Engineering, National University of Singapore, 117576 (Singapore); Department of Mechanical Engineering, National University of Singapore, 117576 (Singapore)

    2012-08-01

    Tissue engineering scaffolds for skin tissue regeneration is an ever expounding area of research, as the products that meet the necessary requirements are far and elite. The nanofibrous poly-L-lactic acid/poly-({alpha},{beta})-DL-aspartic acid/Collagen (PLLA/PAA/Col I and III) scaffolds were fabricated by electrospinning and characterized by SEM, contact angle and FTIR analysis for skin tissue regeneration. The cell-scaffold interactions were analyzed by cell proliferation and their morphology observed in SEM. The results showed that the cell proliferation was significantly increased (p {<=} 0.05) in PLLA/PAA/Col I and III scaffolds compared to PLLA and PLLA/PAA nanofibrous scaffolds. The abundance and accessibility of adipose derived stem cells (ADSCs) may prove to be novel cell therapeutics for dermal tissue regeneration. The differentiation of ADSCs was confirmed using collagen expression and their morphology by CMFDA dye extrusion technique. The current study focuses on the application of PLLA/PAA/Col I and III nanofibrous scaffolds for skin tissue engineering and their potential use as substrate for the culture and differentiation of ADSCs. The objective for inclusion of a novel cell binding moiety like PAA was to replace damaged extracellular matrix and to guide new cells directly into the wound bed with enhanced proliferation and overall organization. This combinatorial epitome of PLLA/PAA/Col I and III nanofibrous scaffold with stem cell therapy to induce the necessary paracrine signalling effect would favour faster regeneration of the damaged skin tissues. - Highlights: Black-Right-Pointing-Pointer Differentiation of adipose derived stem cells in the presence of bFGF for wound healing Black-Right-Pointing-Pointer Introduction of PAA as ECM mimetic cell binding moiety Black-Right-Pointing-Pointer Combination of PLLA/PAA/Col I and III nanofibers and stem cell therapy for skin regeneration.

  19. A Novel Nanohybrid Nanofibrous Adsorbent for Water Purification from Dye Pollutants

    DEFF Research Database (Denmark)

    Homaeigohar, Shahin; Zillohu, Ahnaf; Abdelaziz, Ramzy

    2016-01-01

    In this study, we devised a novel nanofibrous adsorbent made of polyethersulfone (PES) for removal of methylene blue (MB) dye pollutant from water. The polymer shows a low isoelectric point thus at elevated pHs and, being nanofibrous, can offer a huge highly hydroxylated surface area for adsorption...

  20. Fabricating electrospun cellulose nanofibre adsorbents for ion-exchange chromatography.

    Science.gov (United States)

    Dods, Stewart R; Hardick, Oliver; Stevens, Bob; Bracewell, Daniel G

    2015-01-09

    Protein separation is an integral step in biopharmaceutical manufacture with diffusion-limited packed bed chromatography remaining the default choice for industry. Rapid bind-elute separation using convective mass transfer media offers advantages in productivity by operating at high flowrates. Electrospun nanofibre adsorbents are a non-woven fibre matrix of high surface area and porosity previously investigated as a bioseparation medium. The effects of compression and bed layers, and subsequent heat treatment after electrospinning cellulose acetate nanofibres were investigated using diethylaminoethyl (DEAE) or carboxylate (COO) functionalisations. Transbed pressures were measured and compared by compression load, COO adsorbents were 30%, 70% and 90% higher than DEAE for compressions 1, 5 and 10MPa, respectively, which was attributed to the swelling effect of hydrophilic COO groups. Dynamic binding capacities (DBCs) at 10% breakthrough were measured between 2000 and 12,000CV/h (2s and 0.3s residence times) under normal binding conditions, and DBCs increased with reactant concentration from 4 to 12mgBSA/mL for DEAE and from 10 to 21mglysozyme/mL for COO adsorbents. Comparing capacities of compression loads applied after electrospinning showed that the lowest load tested, 1MPa, yielded the highest DBCs for DEAE and COO adsorbents at 20mgBSA/mL and 27mglysozyme/mL, respectively. At 1MPa, DBCs were the highest for the lowest flowrate tested but stabilised for flowrates above 2000CV/h. For compression loads of 5MPa and 10MPa, adsorbents recorded lower DBCs than 1MPa as a result of nanofibre packing and reduced surface area. Increasing the number of bed layers from 4 to 12 showed decreasing DBCs for both adsorbents. Tensile strengths were recorded to indicate the mechanical robustness of the adsorbent and be related to packing the nanofibre adsorbents in large scale configurations such as pleated cartridges. Compared with an uncompressed adsorbent, compressions of 1, 5

  1. Structure-property relationships in Sterculia urens/polyvinyl alcohol electrospun composite nanofibres.

    Science.gov (United States)

    Patra, Niranjan; Martinová, Lenka; Stuchlik, Martin; Černík, Miroslav

    2015-04-20

    Sterculia urens (Gum Karaya) based polyvinyl alcohol (PVA) composite nanofibres have been successfully electrospun after chemical modification of S. urens to increase its solubility. The effect of deacetylated S. urens (DGK) on the morphology, structure, crystallization behaviour and thermal stability was studied for spuned fibres before and after spinning post treatment. An apparent increase in the PVA crystallinity were observed in the PVA-DGK composite nanofibres indicating S. urens induced crystallization of PVA. The pure PVA nanofibre and the nanofibres of PVA-DGK composites were introduced to post electrospinning heat treatment at 150°C for 15 min. The presence of sterculia gum reduced the fibre diameter and distribution of the nanofibres due to the increased stretching of the fibres during spinning. Switching of the thermal behaviour occurs due to post spinning heat treatments.

  2. Hydroxypropyl chitosan/organic rectorite-based nanofibrous mats with intercalated structure for bacterial inhibition.

    Science.gov (United States)

    Deng, Hongbing; Lin, Penghua; Li, Wei; Xin, Shangjing; Zhou, Xue; Yang, Jianhong

    2013-01-01

    This paper reported antibacterial hydroxypropyl chitosan (HPCS)/organic rectorite (OREC)-based nanofibrous mats with intercalated structure fabricated via solution intercalation method and electrospinning. Field emission scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectra, Energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and inhibition zone surrounding circular mats disks measurement were performed to characterize the morphology, intercalation structure, elements analysis, and the antibacterial properties of the as-spun nanofibrous mats. The results showed that the nanofibrous mats were with better fiber shape with the addition of OREC, the polymer chains were successfully intercalated into the interlayer of OREC, and nanofibrous mats containing HPCS exhibited good antibacterial activities against Gram-negative bacteria Escherichia coli and Gram-positive bacteria Staphylococcus aureus. In addition, the bacterial inhibition ability of the nanofibrous mats was enhanced when OREC was added.

  3. Multi-level cascaded electromagnetically induced transparency in cold atoms using an optical nanofibre interface

    CERN Document Server

    Kumar, Ravi; Chormaic, Síle Nic

    2015-01-01

    Ultrathin optical fibres integrated into cold atom setups are proving to be ideal building blocks for atom-photon hybrid quantum networks. Such optical nanofibres (ONF) can be used for the demonstration of nonlinear optics and quantum interference phenomena in atomic media. Here, we report on the observation of multilevel cascaded electromagnetically induced transparency (EIT) using an optical nanofibre to interface cold $^{87}$Rb atoms through the intense evanescent fields that can be achieved at ultralow probe and coupling powers. Both the probe (at 780 nm) and the coupling (at 776 nm) beams propagate through the nanofibre. The observed multipeak transparency spectra of the probe beam could offer a method for simultaneously slowing down multiple wavelengths in an optical nanofibre or for generating ONF-guided entangled beams, showing the potential of such an atom-nanofibre system for quantum information. We also demonstrate all-optical-switching in the all fibred system using the obtained EIT effect.

  4. Fabrication of polyaniline/carboxymethyl cellulose/cellulose nanofibrous mats and their biosensing application

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiapeng, E-mail: firgexiao@sina.cn; Pang, Zengyuan, E-mail: pangzengyuan1212@163.com; Yang, Jie, E-mail: young1993@126.com; Huang, Fenglin, E-mail: flhuang@jiangnan.edu.cn; Cai, Yibing, E-mail: yibingcai@jiangnan.edu.cn; Wei, Qufu, E-mail: qfwei@jiangnan.edu.cn

    2015-09-15

    Graphical abstract: - Highlights: • PANI nanorods have been grown onto the surface of CMC/cellulose nanofibers for the fabrication of biosensor substrate material. • The proposed laccase biosensor exhibited a low detection limit and high sensitivity in the detection of catechol. • Hierarchical PANI/CMC/cellulose nanofibers are the promising material in the design of high-efficient biosensors. - Abstract: We report a facile approach to synthesizing and immobilizing polyaniline nanorods onto carboxymethyl cellulose (CMC)-modified cellulose nanofibers for their biosensing application. Firstly, the hierarchical PANI/CMC/cellulose nanofibers were fabricated by in situ polymerization of aniline on the CMC-modified cellulose nanofiber. Subsequently, the PANI/CMC/cellulose nanofibrous mat modified with laccase (Lac) was used as biosensor substrate material for the detection of catechol. PANI/CMC/cellulose nanofibers with highly conductive and three dimensional nanostructure were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectra (FT-IR), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under optimum conditions, the Lac/PANI/CMC/cellulose/glassy carbon electrode (GCE) exhibited a fast response time (within 8 s), a linear response range from 0.497 μM to 2.27 mM with a high sensitivity and low detection limit of 0.374 μM (3σ). The developed biosensor also displayed good repeatability, reproducibility as well as selectivity. The results indicated that the composite mat has potential application in enzyme biosensors.

  5. Quaternized chitosan-coated nanofibrous materials containing gossypol: preparation by electrospinning, characterization and antiproliferative activity towards HeLa cells.

    Science.gov (United States)

    Ignatova, Milena; Manolova, Nevena; Toshkova, Reneta; Rashkov, Iliya; Gardeva, Elena; Yossifova, Liliya; Alexandrov, Marin

    2012-10-15

    Nanofibrous polylactide-based materials loaded with a natural polyphenolic compound gossypol (GOS) with antitumor properties were prepared by electrospinning. The nanofibrous materials were coated with a thin film of crosslinked quaternized chitosan (QCh). GOS incorporated in the nanofibrous mats was in the amorphous state. GOS release was diffusion-controlled and its in vitro release profiles depended on the mat composition. The nanofibrous materials exhibited high cytotoxicity towards HeLa tumor cells. Interestingly, it was particularly pronounced in the case of fibrous materials, which contain both QCh and GOS. The observed strong antiproliferative effect of the nanofibrous mats was mainly due to induction of cell apoptosis.

  6. The influence of substrate temperature on growth of para-sexiphenyl thin films on Ir(111) supported graphene studied by LEEM

    NARCIS (Netherlands)

    Khokhar, F.S.; Hlawacek, G.; Gastel, van R.; Zandvliet, H.J.W.; Teichert, C.; Poelsema, B.

    2012-01-01

    The growth of para-sexiphenyl (6P) thin films as a function of substrate temperature on Ir{111} supported graphene flakes has been studied in real-time with Low Energy Electron Microscopy (LEEM). Micro Low Energy Electron Diffraction (μLEED) has been used to determine the structure of the different

  7. The influence of substrate temperature on growth of para-sexiphenyl thin films on Ir(111) supported graphene studied by LEEM

    NARCIS (Netherlands)

    Khokhar, F.S.; Hlawacek, G.; van Gastel, Raoul; Zandvliet, Henricus J.W.; Teichert, C.; Poelsema, Bene

    2012-01-01

    The growth of para-sexiphenyl (6P) thin films as a function of substrate temperature on Ir{111} supported graphene flakes has been studied in real-time with Low Energy Electron Microscopy (LEEM). Micro Low Energy Electron Diffraction (μLEED) has been used to determine the structure of the different

  8. Microstructure and properties of nano-fibrous PCL-b-PLLA scaffolds for cartilage tissue engineering

    Directory of Open Access Journals (Sweden)

    L He

    2009-10-01

    Full Text Available Nano-fibrous scaffolds which could potentially mimic the architecture of extracellular matrix (ECM have been considered a good candidate matrix for cell delivery in tissue engineering applications. In the present study, a semicrystalline diblock copolymer, poly(e-caprolactone-block-poly(L-lactide (PCL-b-PLLA, was synthesized and utilized to fabricate nano-fibrous scaffolds via a thermally induced phase separation process. Uniform nano-fibrous networks were created by quenching a PCL-b-PLLA/THF homogenous solution to -20ºC or below, followed by further gelation for 2 hours due to the presence of PLLA and PCL microcrystals. However, knot-like structures as well as continuously smooth pellicles appeared among the nano-fibrous network with increasing gelation temperature. DSC analysis indicated that the crystallization of PCL segments was interrupted by rigid PLLA segments, resulting in an amorphous phase at high gelation temperatures. Combining TIPS (thermally induced phase separation with salt-leaching methods, nano-fibrous architecture and interconnected pore structures (144±36 mm in diameter with a high porosity were created for in vitro culture of chondrocytes. Specific surface area and protein adsorption on the surface of the nano-fibrous scaffold were three times higher than on the surface of the solid-walled scaffold. Chondrocytes cultured on the nano-fibrous scaffold exhibited a spherical condrocyte-like phenotype and secreted more cartilage-like extracellular matrix (ECM than those cultured on the solid-walled scaffold. Moreover, the protein and DNA contents of cells cultured on the nano-fibrous scaffold were 1.2-1.4 times higher than those on the solid-walled scaffold. Higher expression levels of collagen II and aggrecan mRNA were induced on the nano-fibrous scaffold compared to on the solid-walled scaffold. These findings demonstrated that scaffolds with a nano-fibrous architecture could serve as superior scaffolds for cartilage tissue

  9. Water flattens graphene wrinkles: laser shock wrapping of graphene onto substrate-supported crystalline plasmonic nanoparticle arrays.

    Science.gov (United States)

    Hu, Yaowu; Lee, Seunghyun; Kumar, Prashant; Nian, Qiong; Wang, Wenqi; Irudayaraj, Joseph; Cheng, Gary J

    2015-12-21

    Hot electron injection into an exceptionally high mobility material can be realized in graphene-plasmonic nanoantenna hybrid nanosystems, which can be exploited for several front-edge applications including photovoltaics, plasmonic waveguiding and molecular sensing at trace levels. Wrinkling instabilities of graphene on these plasmonic nanostructures, however, would cause reactive oxygen or sulfur species to diffuse and react with the materials, decrease charge transfer rates and block intense hot-spots. No ex situ graphene wrapping technique has been explored so far to control these wrinkles. Here, we present a method to generate seamless integration by using water as a flyer to transfer the laser shock pressure to wrap graphene onto plasmonic nanocrystals. This technique decreases the interfacial gap between graphene and the covered substrate-supported plasmonic nanoparticle arrays by exploiting a shock pressure generated by the laser ablation of graphite and the water impermeable nature of graphene. Graphene wrapping of chemically synthesized crystalline gold nanospheres, nanorods and bipyramids with different field confinement capabilities is investigated. A combined experimental and computational method, including SEM and AFM morphological investigation, molecular dynamics simulation, and Raman spectroscopy characterization, is used to demonstrate the effectiveness of this technique. Graphene covered gold bipyramid exhibits the best result among the hybrid nanosystems studied. We have shown that the hybrid system fabricated by laser shock can be used for enhanced molecular sensing. The technique developed has the characteristics of tight integration, and chemical/thermal stability, is instantaneous in nature, possesses a large scale and room temperature processing capability, and can be further extended to integrate other 2D materials with various 0-3D nanomaterials.

  10. Substrate supporting disc method for confirmed detection of total coliforms and E. coli in all foods: collaborative study.

    Science.gov (United States)

    Feldsine, P T; Falbo-Nelson, M T; Hustead, D L

    1993-01-01

    The ColiComplete substrate supporting disc (SSD) method for simultaneous confirmed total coliform count and Escherichia coli determination in all foods was compared with AOAC most probable number (MPN) methods, 966.23 and 966.24. Twenty-nine laboratories participated in this collaborative study in which 6 food types were analyzed. Four food types, raw ground beef, pork sausage, raw liquid milk, and nut meats, were naturally contaminated with coliform bacteria. Two foods, dry egg and fresh frozen vegetables, were seeded with coliforms. Three food types, ground beef, raw liquid milk, and pork sausage, were naturally contaminated with E. coli. Although pork sausage was naturally contaminated, the level was very low (food type. Three food types, nut meats, dry egg, and fresh frozen vegetables, were inoculated with E. coli. For naturally contaminated samples, duplicate determinations were made on 3 separate lots for each food type. For inoculated samples, low, medium, and high contamination levels plus uninoculated control samples were examined in duplicate. Data were analyzed separately for total coliform bacteria and for E. coli. Mean log MPN counts were determined by the SSD method and the appropriate AOAC MPN method. Results were then analyzed for repeatability, reproducibility, and mean log MPN statistical equivalence. Results were statistically equivalent for all total coliform levels in all food types except frozen vegetable and raw nut meat uninoculated control samples and 1 lot of pork sausage where the SSD method produced statistically significant greater numbers. For the E. coli determinations, results were statistically equivalent across all samples and all levels for each food type. The SSD method has been adopted first action by AOAC International for confirmed detection of total coliforms and E. coli in all foods.

  11. Epitaxial growth of sexi-thiophene and para-hexaphenyl and its implications for the fabrication of self-assembled lasing nano-fibres

    Science.gov (United States)

    Simbrunner, Clemens

    2013-05-01

    Over the last few years, epitaxially grown self-assembled organic nano-structures became of increasing interest due to their high potential for implementation within opto-electronic devices. Exemplarily, the epitaxial growth of the rod-like molecules para-hexaphenyl (p-6P) and α-sexi-thiophene (6T) is discussed within this review. Both molecules tend to crystallize in highly asymmetric elongated entities which are also called nano-fibres. It is demonstrated that the obtained needle orientations and morphologies result from a complex interplay between various parameters e.g. substrate surface symmetry, molecular adsorption, crystal structure and contact plane. The interplay and its implications on the fabrication of self-assembled waveguiding nano-fibres and optical resonator structures are discussed and substantiated by a comparison with the reported literature. In further consequence, it is demonstrated that a precise control on the molecular adsorption geometry and the crystal contact plane represents a fundamental key parameter for the fabrication of self-assembled nano-fibres. As both parameters are basically determined by the chosen molecule-substrate material couple, the possible spectrum of molecular building blocks for the fabrication of waveguiding and lasing nano-structures can be predicted by the discussed growth model. A possible expansion of this common valid concept is presented by the utilization of organic-organic heteroepitaxy. Based on the reported p-6P/6T heterostructures which have been fabricated on various substrate surfaces, it is substantiated that the fabrication of organic-organic interfaces can be effectively used to gain control on the molecular adsorption geometry. As the proposed strategy still lacks a precise control of the obtained crystal contact plane, further strategies are discussed which potentially lead to a controlled fabrication of opto-electronic devices based on self-assembled organic nano-structures.

  12. Mitochondrial diaphorases as NAD+ donors to segments of the citric acid cycle that support substrate-level phosphorylation yielding ATP during respiratory inhibition

    Science.gov (United States)

    Kiss, Gergely; Konrad, Csaba; Pour-Ghaz, Issa; Mansour, Josef J.; Németh, Beáta; Starkov, Anatoly A.; Adam-Vizi, Vera; Chinopoulos, Christos

    2014-01-01

    Substrate-level phosphorylation mediated by succinyl-CoA ligase in the mitochondrial matrix produces high-energy phosphates in the absence of oxidative phosphorylation. Furthermore, when the electron transport chain is dysfunctional, provision of succinyl-CoA by the α-ketoglutarate dehydrogenase complex (KGDHC) is crucial for maintaining the function of succinyl-CoA ligase yielding ATP, preventing the adenine nucleotide translocase from reversing. We addressed the source of the NAD+ supply for KGDHC under anoxic conditions and inhibition of complex I. Using pharmacologic tools and specific substrates and by examining tissues from pigeon liver exhibiting no diaphorase activity, we showed that mitochondrial diaphorases in the mouse liver contribute up to 81% to the NAD+ pool during respiratory inhibition. Under these conditions, KGDHC's function, essential for the provision of succinyl-CoA to succinyl-CoA ligase, is supported by NAD+ derived from diaphorases. Through this process, diaphorases contribute to the maintenance of substrate-level phosphorylation during respiratory inhibition, which is manifested in the forward operation of adenine nucleotide translocase. Finally, we show that reoxidation of the reducible substrates for the diaphorases is mediated by complex III of the respiratory chain.—Kiss, G., Konrad, C., Pour-Ghaz, I., Mansour, J. J., Németh, B., Starkov, A. A., Adam-Vizi, V., Chinopoulos, C. Mitochondrial diaphorases as NAD+ donors to segments of the citric acid cycle that support substrate-level phosphorylation yielding ATP during respiratory inhibition. PMID:24391134

  13. Novel RNA-binding properties of Pop3p support a role for eukaryotic RNase P protein subunits in substrate recognition.

    Science.gov (United States)

    Brusca, E M; True, H L; Celander, D W

    2001-11-09

    Ribonuclease P (RNase P) catalyzes the 5'-end maturation of transfer RNA molecules. Recent evidence suggests that the eukaryotic protein subunits may provide substrate-binding functions (True, H. L., and Celander, D. W. (1998) J. Biol. Chem. 273, 7193-7196). We now report that Pop3p, an essential protein subunit of the holoenzyme in Saccharomyces cerevisiae, displays novel RNA-binding properties. A recombinant form of Pop3p (H6Pop3p) displays a 3-fold greater affinity for binding pre-tRNA substrates relative to tRNA products. The recognition sequence for the H6Pop3p-substrate interaction in vitro was mapped to a 39-nucleotide long sequence that extends from position -21 to +18 surrounding the natural processing site in pre-tRNA substrates. H6Pop3p binds a variety of RNA molecules with high affinity (K(d) = 16-25 nm) and displays a preference for single-stranded RNAs. Removal or modification of basic C-terminal residues attenuates the RNA-binding properties displayed by the protein specifically for a pre-tRNA substrate. These studies support the model that eukaryotic RNase P proteins bind simultaneously to the RNA subunit and RNA substrate.

  14. Toward a new generation of pelvic floor implants with electrospun nanofibrous matrices: A feasibility study.

    Science.gov (United States)

    Vashaghian, Mahshid; Ruiz-Zapata, Alejandra M; Kerkhof, Manon H; Zandieh-Doulabi, Behrouz; Werner, Arie; Roovers, Jan Paul; Smit, Theo H

    2017-03-01

    The use of knitted, polypropylene meshes for the surgical treatment of pelvic organ prolapse (POP) is frequently accompanied by severe complications. Looking for alternatives, we studied the potential of three different electrospun matrices in supporting the adhesion, proliferation, and matrix deposition of POP and non-POP fibroblasts, the most important cells to produce extracellular matrix (ECM), in vitro. We electrospun three commonly used medical materials: nylon; poly (lactide-co-glycolide) blended with poly-caprolactone (PLGA/PCL); and poly-caprolactone blended with gelatin (PCL/Gelatin). The matrices were characterized for their microstructure, hydrophilicity, and mechanical properties. We seeded POP and non-POP fibroblasts from patients with POP and we determined cellular responses and ECM deposition. All matrices had >65% porosity, homogenous microstructures, and close to sufficient tensile strength for pelvic floor repair: 15.4 ± 3.3 MPa for Nylon; 12.4 ± 1.6 MPa for PLGA/PCL; and 3.5 ± 0.9 MPa for PCL/Gelatin. Both the POP and non-POP cells adhered to the electrospun matrices; they proliferated well and produced ample ECM. Overall, the best in vitro performance appeared to be on nylon, presumably because this was the most hydrophilic material with the thinnest fibers. Electrospun nanofibrous matrices show feasible mechanical strength and great biocompatibility for POP and non-POP fibroblasts to produce their ECM in vitro and, thus, may be candidates for a new generation of implants for pelvic floor repair. Further studies on electrospun nanofibrous matrices should focus on mechanical and immunological conditions that would be presented in vivo. Neurourol. Urodynam. 36:565-573, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  15. Photocatalytic degradation of humic acids using substrate-supported Fe³⁺-doped TiO₂ nanotubes under UV/O₃ for water purification.

    Science.gov (United States)

    Yuan, Rongfang; Zhou, Beihai; Zhang, Xuemin; Guan, Huanhuan

    2015-11-01

    In this paper, Fe(3+)-doped TiO2 nanotubes (Fe-TNTs) were successfully synthesized using hydrothermal method. Four different types of substrates, more specifically, ceramsite, zeolite, activated alumina, and activated carbon (AC), have been investigated in the study. The substrate-supported Fe-TNTs were used to effectively decompose humic acids (HAs) in water under O3/UV conditions. The experiment results show that the highest photocatalytic activity was obtained in the presence of AC-supported 1.0 atomic percent (at.%) Fe-TNTs calcined at 500 °C, as HAs was removed by 97.4%, with a pseudo-first-order rate constant of 0.126/min. The removal efficiencies of HAs reduced when the catalysts was repeatedly used, since the amount of adsorption sites of the supporting substrates decreased. However, even after the catalyst was repeatedly used for five times, the removal efficiency of HAs in the presence of AC-supported catalyst, which was 78.5%, was still sufficient in water treatment. The enhanced photocatalytic activity of AC-supported Fe-TNTs was related to a synergistic effect of AC adsorption and Fe-TNT photocatalytic ozonation.

  16. Regulation of migratory activity of human keratinocytes by topography of multiscale collagen-containing nanofibrous matrices.

    Science.gov (United States)

    Fu, Xiaoling; Xu, Meng; Liu, Jie; Qi, Yanmei; Li, Shaohua; Wang, Hongjun

    2014-02-01

    Nanofibrous matrices hold great promise in skin wound repair partially due to their capability of recapturing the essential attributes of native extracellular matrix (ECM). With regard to limited studies on the effect of nanofibrous matrices on keratinocytes, the present study was aimed to understand how the topographical feature of nanofibrous matrices regulates keratinocyte motility by culturing keratinocytes on polycaprolactone (PCL)/collagen nanofibrous matrices (rough surface with fiber diameters of 331 ± 112 nm) or the matrices coated with a thin layer of collagen gel to form a secondary ultrafine fibrous network (smooth surface with ultrafine fiber diameters of 55 ± 26 nm). It was found that the PCL/collagen nanofibrous matrices alone did not stimulate cell migration, while collagen gel coating could significantly increase cell motility. Further studies demonstrated that the ultrafine fibrous network of collagen gel coating significantly activated integrin β1, Rac1 and Cdc42, facilitated the deposition of laminin-332 (formerly called laminin-5), and promoted the expression of active matrix metalloproteinases (MMPs) (i.e., MMP-2 and 9). Neutralization of integrin β1 activity abrogated the gel coating-induced keratinocyte migration. These findings provide important evidence on the role of topographical features of nanofibrous matrices in regulating the phenotypic alteration of keratinocytes and suggest the possible utility of collagen-containing nanofibrous matrices for skin regeneration especially in re-epithelialization.

  17. Nanofibre distribution in composites manufactured with epoxy reinforced with nanofibrillated cellulose: model prediction and verification

    Science.gov (United States)

    Aitomäki, Yvonne; Westin, Mikael; Korpimäki, Jani; Oksman, Kristiina

    2016-07-01

    In this study a model based on simple scattering is developed and used to predict the distribution of nanofibrillated cellulose in composites manufactured by resin transfer moulding (RTM) where the resin contains nanofibres. The model is a Monte Carlo based simulation where nanofibres are randomly chosen from probability density functions for length, diameter and orientation. Their movements are then tracked as they advance through a random arrangement of fibres in defined fibre bundles. The results of the model show that the fabric filters the nanofibres within the first 20 µm unless clear inter-bundle channels are available. The volume fraction of the fabric fibres, flow velocity and size of nanofibre influence this to some extent. To verify the model, an epoxy with 0.5 wt.% Kraft Birch nanofibres was made through a solvent exchange route and stained with a colouring agent. This was infused into a glass fibre fabric using an RTM process. The experimental results confirmed the filtering of the nanofibres by the fibre bundles and their penetration in the fabric via the inter-bundle channels. Hence, the model is a useful tool for visualising the distribution of the nanofibres in composites in this manufacturing process.

  18. Dual Drug Loaded Biodegradable Nanofibrous Microsphere for Improving Anti-Colon Cancer Activity

    Science.gov (United States)

    Fan, Rangrang; Li, Xiaoling; Deng, Jiaojiao; Gao, Xiang; Zhou, Liangxue; Zheng, Yu; Tong, Aiping; Zhang, Xiaoning; You, Chao; Guo, Gang

    2016-06-01

    One of the approaches being explored to increase antitumor activity of chemotherapeutics is to inject drug-loaded microspheres locally to specific anatomic sites, providing for a slow, long term release of a chemotherapeutic while minimizing systemic exposure. However, the used clinically drug carriers available at present have limitations, such as their low stability, renal clearance and residual surfactant. Here, we report docetaxel (DOC) and curcumin (CUR) loaded nanofibrous microspheres (DOC + CUR/nanofibrous microspheres), self-assembled from biodegradable PLA-PEO-PPO-PEO-PLA polymers as an injectable drug carrier without adding surfactant during the emulsification process. The obtained nanofibrous microspheres are composed entirely of nanofibers and have an open hole on the shell without the assistance of a template. It was shown that these DOC + CUR/nanofibrous microspheres could release curcumin and docetaxel slowly in vitro. The slow, sustained release of curcumin and docetaxel in vivo may help maintain local concentrations of active drug. The mechanism by which DOC + CUR/nanofibrous microspheres inhibit colorectal peritoneal carcinomatosis might involve increased induction of apoptosis in tumor cells and inhibition of tumor angiogenesis. In vitro and in vivo evaluations demonstrated efficacious synergistic antitumor effects against CT26 of curcumin and docetaxel combined nanofibrous microspheres. In conclusion, the dual drug loaded nanofibrous microspheres were considered potentially useful for treating abdominal metastases of colorectal cancer.

  19. Preparation of Titanium Dioxide Nanoparticles Immobilized on Polyacrylonitrile Nanofibres for the Photodegradation of Methyl Orange

    Directory of Open Access Journals (Sweden)

    Pardon Nyamukamba

    2016-01-01

    Full Text Available Herein, we describe the synthesis of titanium dioxide (TiO2 nanoparticles by the hydrolysis and condensation of titanium tetrachloride. The resulting nanoparticles were immobilized on polyacrylonitrile (PAN based nanofibres by an electrospinning technique in order to allow simple isolation and reuse of titania semiconductor photocatalyst. The composite nanofibres were heat treated to convert the polymer nanofibres to carbon nanofibres and to convert amorphous TiO2 to crystalline TiO2. X-ray diffraction (XRD analysis showed that the rutile phase was the major phase and the equatorial peaks of PAN disappeared after heat treatment at 600°C. Transmission electron microscopy (TEM and scanning electron microscopy (SEM analysis confirmed that some TiO2 nanoparticles were encapsulated whereas some were surface residing on the electrospun nanofibres. The TiO2 nanoparticles were found to lower the cyclization temperature of PAN as indicated by differential scanning colorimetry (DSC and differential thermal analysis (DTA. Photocatalytic studies on the degradation of methyl orange dye under UV light irradiation showed that composite nanofibres were capable of degrading organic contaminants in water. The carbon nanofibres with surface residing titanium dioxide nanoparticles (TiO2/CNF-SR showed the highest photocatalytic activity (59.35% after 210 minutes due to direct contact between the TiO2 photocatalyst and methyl orange.

  20. Nanofibre growth from cobalt carbide produced by mechanosynthesis

    Energy Technology Data Exchange (ETDEWEB)

    Diaz Barriga-Arceo, L [Instituto Mexicano del Petroleo, Programa de Ingenieria Molecular, Eje Central Lazaro Cardenas 152, Colonia San Bartolo Atepehuacan, Mexico DF, 07730 (Mexico); Orozco, E [Instituto de Fisica UNAM, Apartado Postal 20-364 CP 01000, DF (Mexico); Garibay-Febles, V [Instituto Mexicano del Petroleo, Programa de Ingenieria Molecular, Eje Central Lazaro Cardenas 152, Colonia San Bartolo Atepehuacan, Mexico DF, 07730 (Mexico); Bucio-Galindo, L [Instituto de Fisica UNAM, Apartado Postal 20-364 CP 01000, DF (Mexico); Mendoza Leon, H [FM-UPALM, IPN, Apartado Postal 75-395 CP 07300, DF (Mexico); Castillo-Ocampo, P [UAM-Iztapalapa, Apartado Postal 55-334 CP 09340, DF (Mexico); Montoya, A [Instituto Mexicano del Petroleo, Programa de Ingenieria Molecular, Eje Central Lazaro Cardenas 152, Colonia San Bartolo Atepehuacan, Mexico DF, 07730 (Mexico)

    2004-06-09

    Mechanical alloying was used to prepare cobalt carbide. Microstructural characterization of samples was performed by x-ray diffraction, differential scanning calorimetry and transmission electron microscopy methods. In order to produce carbon nanotubes, the cobalt carbide was precipitated after heating at 800 and 1000 deg. C for 10 min. Nanofibres of about 10-50 nm in diameter, 0.04-0.1 {mu}m in length and 20-200 nm in diameter and 0.6-1.2 {mu}m in length were obtained after heating at 800 and 1000 deg. C, respectively, by means of this process.

  1. In vivo integration of poly(ε-caprolactone)/gelatin nanofibrous nerve guide seeded with teeth derived stem cells for peripheral nerve regeneration.

    Science.gov (United States)

    Beigi, Mohammad-Hossein; Ghasemi-Mobarakeh, Laleh; Prabhakaran, Molamma P; Karbalaie, Khadijeh; Azadeh, Hamid; Ramakrishna, Seeram; Baharvand, Hossein; Nasr-Esfahani, Mohammad-Hossein

    2014-12-01

    Artificial nanofiber nerve guides have gained huge interest in bridging nerve gaps and associated peripheral nerve regeneration due to its high surface area, flexibility and porous structure. In this study, electrospun poly (ε-caprolactone)/gelatin (PCL/Gel) nanofibrous mats were fabricated, rolled around a copper wire and fixed by medical grade adhesive to obtain a tubular shaped bio-graft, to bridge 10 mm sciatic nerve gap in in vivo rat models. Stem cells from human exfoliated deciduous tooth (SHED) were transplanted to the site of nerve injury through the nanofibrous nerve guides. In vivo experiments were performed in animal models after creating a sciatic nerve gap, such that the nerve gap was grafted using (i) nanofiber nerve guide (ii) nanofiber nerve guide seeded with SHED (iii) suturing, while an untreated nerve gap remained as the negative control. In vitro cell culture study was carried out for primary investigation of SHED-nanofiber interaction and its viability within the nerve guides after 2 and 16 weeks of implantation time. Walking track analysis, plantar test, electrophysiology and immunohistochemistry were performed to evaluate functional recovery during nerve regeneration. Vascularization was also investigated by hematoxilin/eosine (H&E) staining. Overall results showed that the SHED seeded on nanofibrous nerve guide could survive and promote axonal regeneration in rat sciatic nerves, whereby the biocompatible PCL/Gel nerve guide with cells can support axonal regeneration and could be a promising tissue engineered graft for peripheral nerve regeneration.

  2. Electrospun Poly(lactide-co-glycolide-co-3(S-methyl-morpholine-2,5-dione Nanofibrous Scaffolds for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Yakai Feng

    2016-01-01

    Full Text Available Biomimetic scaffolds have been investigated in vascular tissue engineering for many years. Excellent biodegradable materials are desired as temporary scaffolds to support cell growth and disappear gradually with the progress of guided tissue regeneration. In the present paper, a series of biodegradable copolymers were synthesized and used to prepared micro/nanofibrous scaffolds for vascular tissue engineering. Poly(lactide-co-glycolide-co-3(S-methyl-morpholine-2,5-dione [P(LA-co-GA-co-MMD] copolymers with different l-lactide (LA, glycolide (GA, and 3(S-methyl-2,5-morpholinedione (MMD contents were synthesized using stannous octoate as a catalyst. Moreover, the P(LA-co-GA-co-MMD nanofibrous scaffolds were prepared by electrospinning technology. The morphology of scaffolds was analyzed by scanning electron microscopy (SEM, and the results showed that the fibers are smooth, regular, and randomly oriented with diameters of 700 ± 100 nm. The weight loss of scaffolds increased significantly with the increasing content of MMD, indicating good biodegradable property of the scaffolds. In addition, the cytocompatibility of electrospun nanofibrous scaffolds was tested by human umbilical vein endothelial cells. It is demonstrated that the cells could attach and proliferate well on P(LA-co-GA-co-MMD scaffolds and, consequently, form a cell monolayer fully covering on the scaffold surface. Furthermore, the P(LA-co-GA-co-MMD scaffolds benefit to excellent cell infiltration after subcutaneous implantation. These results indicated that the P(LA-co-GA-co-MMD nanofibrous scaffolds could be potential candidates for vascular tissue engineering.

  3. Study of polyvinyl alcohol nanofibrous membrane by electrospinning as a magnetic nanoparticle delivery approach

    Science.gov (United States)

    Ger, Tzong-Rong; Huang, Hao-Ting; Huang, Chen-Yu; Hu, Keng-Shiang; Lai, Jun-Yang; Chen, Jiann-Yeu; Lai, Mei-Feng

    2014-05-01

    Electrospinning technique was used to fabricate polyvinyl alcohol (PVA)-based magnetic biodegradable nanofibers. PVA solution was mixed with ferrofluid or magnetic nanoparticles (MNPs) powder and formed two individual nanofibrous membranes (PVA/ferrofluid and PVA/MNPs powder) by electrospinning. The surface morphology of the nanofibrous membrane was characterized by scanning electron microscopy and the magnetic properties were measured by vibrating sample magnetometer. Macrophages (RAW 264.7) were co-cultured with the nanofibrous membranes for 12, 24, and 48 h and exhibited good cell viability (>95%). Results showed that the PVA fibers would be degraded and the embedded Fe3O4 nanoparticles would be released and delivered to cells.

  4. Immobilisation of cyclodextrin glucanotransferase into polyvinyl alcohol (PVA) nanofibres via electrospinning

    OpenAIRE

    2016-01-01

    Immobilisation of cyclodextrin glucanotransferase (CGTase) on nanofibres was demonstrated. CGTase solution (1% v/v) and PVA (8 wt%) solution were mixed followed by electrospinning (−9 kV, 3 h). CGTase/PVA nanofibres with an average diameter of 176 ± 46 nm were successfully produced. The nanofibres that consist of immobilised CGTase were crosslinked with glutaraldehyde vapour. A CGTase/PVA film made up from the same mixture and treated the same way was used as a control experiment. The immobil...

  5. Removal of copper ions from aqueous solution by adsorption onto novel polyelectrolyte film-coated nanofibrous silk fibroin non-wovens

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Weitao, E-mail: weitao_zhou@yahoo.com [Key Laboratory of Functional Textiles, The Education Department of Henan Province, Zhongyuan University of Technology, Zhengzhou 450007 (China); Huang, Haitao [School of Textile, Henan Institute of Engineering, Zhengzhou 451191 (China); Du, Shan [Australian Future Fibers Research and Innovation Centre for Frontier Materials, Deakin University, Geelong, VIC 3217 (Australia); Huo, Yingdong; He, Jianxin [Key Laboratory of Functional Textiles, The Education Department of Henan Province, Zhongyuan University of Technology, Zhengzhou 450007 (China); Cui, Shizhong, E-mail: snowballer@163.com [Key Laboratory of Functional Textiles, The Education Department of Henan Province, Zhongyuan University of Technology, Zhengzhou 450007 (China)

    2015-08-01

    Graphical abstract: - Highlights: • Polyethylenimine coated silk fibroin nanofibrous nonwovens were fabricated. • The characteristics such as the fiber shape and porous structure were well maintained. • The structure and adsorption properties were studied. The adsorption property for copper ions is good. - Abstract: In this approach, polyelectrolyte film-coated nanofibrous silk fibroin (SF) nonwovens were prepared from the alternate deposition of positively charged polyethylenimine (PEI) and negatively charged SF using electrostatic layer-by-layer (LBL) self-assembled technology. The composite membranes were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectrometer. The SF-PEI multilayer-assembled nanofibers (less than five layers) were fine and uniform with the fiber diameter from 400 nm to 600 nm, and had very large surface area and high porosity (more than 70%). The amino groups of PEI were proved to be deposited onto SF nonwovens, which granted the coated nonwovens with potential applicability for copper ions adsorption. The PEI films coated SF substrate showed much higher copper ions adsorption capacity than that of ethanol treated SF nanofibers. Adding the number of PEI coated could enhance the Cu{sup 2+} adsorption capacity significantly. The maximum milligrams per gram of copper ions adsorbed reached 59.7 mg/g when the SF substrate was coated with 5 bilayers of SF-PEI. However, the copper ions adsorption capacity had no obvious change as the number of PEI continued to increase. These results suggest potential for PEL film-coated nanofibrous nonwovens as a new adsorbent for metal ions.

  6. Enhanced growth of neural networks on conductive cellulose-derived nanofibrous scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmenko, Volodymyr [Wallenberg Wood Science Center, Chalmers University of Technology, Kemivägen 4, SE-412 96 Gothenburg (Sweden); Department of Microtechnology and Nanoscience, Chalmers University of Technology, Kemivägen 9, SE-412 96 Gothenburg (Sweden); Kalogeropoulos, Theodoros [Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 4, SE-412 96 Gothenburg (Sweden); Thunberg, Johannes [Wallenberg Wood Science Center, Chalmers University of Technology, Kemivägen 4, SE-412 96 Gothenburg (Sweden); Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 4, SE-412 96 Gothenburg (Sweden); Johannesson, Sara; Hägg, Daniel [Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 4, SE-412 96 Gothenburg (Sweden); Enoksson, Peter [Wallenberg Wood Science Center, Chalmers University of Technology, Kemivägen 4, SE-412 96 Gothenburg (Sweden); Department of Microtechnology and Nanoscience, Chalmers University of Technology, Kemivägen 9, SE-412 96 Gothenburg (Sweden); Gatenholm, Paul, E-mail: paul.gatenholm@chalmers.se [Wallenberg Wood Science Center, Chalmers University of Technology, Kemivägen 4, SE-412 96 Gothenburg (Sweden); Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Kemivägen 4, SE-412 96 Gothenburg (Sweden)

    2016-01-01

    The problem of recovery from neurodegeneration needs new effective solutions. Tissue engineering is viewed as a prospective approach for solving this problem since it can help to develop healthy neural tissue using supportive scaffolds. This study presents effective and sustainable tissue engineering methods for creating biomaterials from cellulose that can be used either as scaffolds for the growth of neural tissue in vitro or as drug screening models. To reach this goal, nanofibrous electrospun cellulose mats were made conductive via two different procedures: carbonization and addition of multi-walled carbon nanotubes. The resulting scaffolds were much more conductive than untreated cellulose material and were used to support growth and differentiation of SH-SY5Y neuroblastoma cells. The cells were evaluated by scanning electron microscopy and confocal microscopy methods over a period of 15 days at different time points. The results showed that the cellulose-derived conductive scaffolds can provide support for good cell attachment, growth and differentiation. The formation of a neural network occurred within 10 days of differentiation, which is a promising length of time for SH-SY5Y neuroblastoma cells. - Highlights: • The conductive scaffolds for neural tissue engineering are derived from cellulose. • The scaffolds are used to support growth and differentiation of SH-SY5Y cells. • Distinctive cell differentiation occurs within 10 days on conductive scaffolds. • Electrical conductivity and nanotopography improve neural network formation.

  7. Embryonic stem cells growing in 3-dimensions shift from reliance on the substrate to each other for mechanical support.

    Science.gov (United States)

    Teo, Ailing; Lim, Mayasari; Weihs, Daphne

    2015-07-16

    Embryonic stem cells (ESCs) grow into three-dimensional (3D) spheroid structures en-route to tissue growth. In vitro spheroids can be controllably induced on a two-dimensional (2D) substrate with high viability. Here we use a method for inducing pluripotent embryoid body (EB) formation on flat polyacrylamide gels while simultaneously evaluating the dynamic changes in the mechano-biology of the growing 3D spheroids. During colony growth in 3D, pluripotency is conserved while the spheroid-substrate interactions change significantly. We correlate colony-size, cell-applied traction-forces, and expressions of cell-surface molecules indicating cell-cell and cell-substrate interactions, while verifying pluripotency. We show that as the colony size increases with time, the stresses applied by the spheroid to the gel decrease in the 3D growing EBs; control cells growing in 2D-monolayers maintain unvarying forces. Concurrently, focal-adhesion mediated cell-substrate interactions give way to E-cadherin cell-cell connections, while pluripotency. The mechano-biological changes occurring in the growing embryoid body are required for stabilization of the growing pluripotent 3D-structure, and can affect its potential uses including differentiation. This could enable development of more effective expansion, differentiation, and separation approaches for clinical purposes.

  8. NanoFIBrication of a two-dimensional phononic crystal in a free standing membrane.

    Energy Technology Data Exchange (ETDEWEB)

    Leseman, Zayd C. (University of New Mexico, Albuquerque, NM); Goettler, Drew F. (University of New Mexico, Albuquerque, NM); Su, Mehmet F. (University of New Mexico, Albuquerque, NM); El-Kady, Ihab Fathy; Olsson, Roy H., III

    2010-06-01

    A two-dimensional phononic crystal (PnC) that can operate in the GHz range is created in a freestanding silicon substrate using NanoFIBrication (using a focused ion beam (FIB) to fabricate nanostructures). First, a simple cubic 6.75 x 6.75 ?m array of vias with 150 nm spacing is generated. After patterning the vias, they are backfilled with void-free tungsten scatterers. Each via has a diameter of 48 nm. Numerical calculations predict this 2D PnC will generate a band gap near 22 GHz. A protective layer of chromium on top of the thin (100 nm) silicon membrane confines the surface damage to the chromium, which can be removed at a later time. Inspection of the underside of the membrane shows the vias flaring out at the exit, which we are dubbing the 'trumpet effect'. The trumpet effect is explained by modeling the lateral damage in a freestanding membrane.

  9. Polyetherimide Nanofibres as Sorbents for Organochlorinated Pesticides Determination

    Directory of Open Access Journals (Sweden)

    Antoš Vojtěch

    2016-01-01

    Full Text Available Electrospun polyetherimide (PEI nanofibres were fixed on a steel wire solid phase microextraction (SPME assembly. The basic properties of the prepared nanofibres were determined by thermogravimetry, differential scanning calorimetry, adsorption, and SEM. The analytical performance of prepared PEI SPME fibres was compared with three commercially available SPME fibres, 7 μm PDMS, 100 μm PDMS, and DVB/Carboxene/PDMS. As model water pollutants, persistent organochlorinated pesticides hexachlorocyclohexanes (HCH and chlorobenzene (ClB were chosen as model water pollutants. The fibres were compared in the headspace- (HS- SPME mode of GC-MS/MS instrumentation. The comparison omitted other method parameters and focused exclusively on the extraction time variability. Lab-made PEI SPME fibres showed significantly better response for the target compounds than the other tested fibres from industrial production. Based on the results, the extraction time could be shortened from 50 to 10 min, if PEI SPME fibres were used as a modification of existing analytical protocol.

  10. A Mucoadhesive Electrospun Nanofibrous Matrix for Rapid Oramucosal Drug Delivery

    Directory of Open Access Journals (Sweden)

    Clare Dott

    2013-01-01

    Full Text Available A nanofibrous matrix system (NFMS, consisting of a drug-loaded nanofiber layer, was electrospun directly onto a polymeric backing film, the latter of which was formulated and optimized according to a 3-level, 3-factor Box-Behnken experimental design. The dependent variables, fill volume, hydroxypropylmethylcellulose (HPMC concentration, and glycerol concentration, were assessed for their effects on measured responses, disintegration time, work of adhesion, force of adhesion, dissolution area under curve (AUC at 1 minute, and permeation AUC at 3 minutes. Physicochemical and physicomechanical properties of the developed system were studied by rheology, FTIR, toughness determination, mucoadhesion, and nanotensile testing. Data obtained from the physicomechanical characterization confirmed the suitability of NFMS for application in oramucosal drug delivery. The optimized NFMS showed the drug entrapment of 2.3 mg/1.5 cm2 with disintegration time of 12.8 seconds. Electrospinning of drug-loaded polyvinylalcohol (PVA fibers resulted in a matrix with an exceedingly high surface-area-to-volume ratio, which enhanced the rate of dissolution for rapid oramucosal drug delivery. To corroborate with the experimental studies, the incorporation of glycerol with HPMC and PVA blend was mechanistically elucidated using computer-assisted modeling of the 3D polymeric architecture of the respective molecular complexes to envisage the likely alignment of the polymer morphologies affecting the performance of the nanofibrous device.

  11. Silk porous scaffolds with nanofibrous microstructures and tunable properties.

    Science.gov (United States)

    Lu, Guozhong; Liu, Shanshan; Lin, Shasha; Kaplan, David L; Lu, Qiang

    2014-08-01

    Scaffold biomaterials derived from silk fibroin have been widely used in tissue engineering. However, mimicking the nanofibrous structures of the extracellular matrix (ECM) for achieving better biocompatibility remains a challenge. Here, we design a mild self-assembly approach to prepare nanofibrous scaffolds from silk fibroin solution. Silk nanofibers were self-assembled by slowly concentrating process in aqueous solution without any cross-linker or toxic solvent and then were further fabricated into porous scaffolds with pore size of about 200-250μm through lyophilization, mimicking nano and micro structures of ECM. Gradient water/methanol annealing treatments were used to control the secondary structures, mechanical properties, and degradation behaviors of the scaffolds, which would be critical for different tissue regeneration applications. With salt-leached silk scaffold as control, the ECM-mimetic scaffolds with different secondary structures were used to culture the amniotic fluid-derived stem cells in vitro to confirm their biocompatibility. All the ECM-mimetic scaffolds with different secondary structures represented better cell growth and proliferation compared to the salt-leached scaffold, confirming the critical influence of ECM-mimetic structure on biocompatibility. Although further studies such as cell differentiation behaviours are still necessary for clarifying the influence of microstructures and secondary conformational compositions, our study provides promising scaffold candidate that is suitable for different tissue regenerations.

  12. Electrospun regenerated cellulose nanofibrous membranes surface-grafted with polymer chains/brushes via the atom transfer radical polymerization method for catalase immobilization.

    Science.gov (United States)

    Feng, Quan; Hou, Dayin; Zhao, Yong; Xu, Tao; Menkhaus, Todd J; Fong, Hao

    2014-12-10

    In this study, an electrospun regenerated cellulose (RC) nanofibrous membrane with fiber diameters of ∼200-400 nm was prepared first; subsequently, 2-hydroxyethyl methacrylate (HEMA), 2-dimethylaminoethyl methacrylate (DMAEMA), and acrylic acid (AA) were selected as the monomers for surface grafting of polymer chains/brushes via the atom transfer radical polymerization (ATRP) method. Thereafter, four nanofibrous membranes (i.e., RC, RC-poly(HEMA), RC-poly(DMAEMA), and RC-poly(AA)) were explored as innovative supports for immobilization of an enzyme of bovine liver catalase (CAT). The amount/capacity, activity, stability, and reusability of immobilized catalase were evaluated, and the kinetic parameters (Vmax and Km) for immobilized and free catalase were determined. The results indicated that the respective amounts/capacities of immobilized catalase on RC-poly(HEMA) and RC-poly(DMAEMA) nanofibrous membranes reached 78 ± 3.5 and 67 ± 2.7 mg g(-1), which were considerably higher than the previously reported values. Meanwhile, compared to that of free CAT (i.e., 18 days), the half-life periods of RC-CAT, RC-poly(HEMA)-CAT, RC-poly(DMAEMA)-CAT, and RC-poly(AA)-CAT were 49, 58, 56, and 60 days, respectively, indicating that the storage stability of immobilized catalase was also significantly improved. Furthermore, the immobilized catalase exhibited substantially higher resistance to temperature variation (tested from 5 to 70 °C) and lower degree of sensitivity to pH value (tested from 4.0 and 10.0) than the free catalase. In particular, according to the kinetic parameters of Vmax and Km, the nanofibrous membranes of RC-poly(HEMA) (i.e., 5102 μmol mg(-1) min(-1) and 44.89 mM) and RC-poly(DMAEMA) (i.e., 4651 μmol mg(-1) min(-1) and 46.98 mM) had the most satisfactory biocompatibility with immobilized catalase. It was therefore concluded that the electrospun RC nanofibrous membranes surface-grafted with 3-dimensional nanolayers of polymer chains/brushes would be

  13. Electrospun chitosan nanofibre membranes for antimicrobial application: role of electrospinning processing parameters

    CSIR Research Space (South Africa)

    Jacobs, V

    2010-01-01

    Full Text Available for biomedical applications such as wound dressing. In this paper, the authors report investigation on the effects of governing parameters on the formation of chitosan nanofibre membranes. These membranes were subjected to various cell cultures for antibacterial...

  14. Polydopamine coated electrospun poly(vinyldiene fluoride) nanofibrous membrane as separator for lithium-ion batteries

    Science.gov (United States)

    Cao, Chengying; Tan, Lei; Liu, Weiwei; Ma, Jiquan; Li, Lei

    2014-02-01

    In this study, polydopamine (PDA) coated electrospun poly(vinyldiene fluoride) (PVDF) nanofibrous membranes used as separator for lithium-ion batteries are successfully prepared. Their morphology, chemical and electrochemical characterization are investigated. The morphology and porosity measurements of the membranes show that the PDA coating does not harm to the structure of the electrospun PVDF nanofibrous membranes. Due to the PDA coating, it makes the PVDF surface hydrophilic and thus increases the electrolyte uptake and ionic conductivity, resulting in the enhanced performance of batteries. The battery using the PDA coated PVDF nanofibrous separator exhibits better cycling performance and higher power capability than that the battery using the bare PVDF nanofibrous separator. This study underlines that the PDA-coating treatment provides a promising process for the fabrication of advanced electrospun nanofibers separator in the lithium-ion battery applications.

  15. Efficacy of nanofibrous conduits in repair of long-segment sciatic nerve defects*

    Institute of Scientific and Technical Information of China (English)

    Esmaeil Biazar; Saeed Heidari Keshel; Majid Pouya

    2013-01-01

    Our previous studies have histomorphological y confirmed that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) conduit can be used to repair 30-mm-long sciatic nerve defects. However, the repair effects on rat behaviors remain poorly understood. In this study, we used nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) conduit and autologous sciatic nerve to bridge 30-mm-long rat sciatic nerve gaps. Within 4 months after surgery, rat sciatic nerve functional re-covery was evaluated per month by behavioral analyses, including toe out angle, toe spread anal-ysis, walking track analysis, extensor postural thrust, swimming test, open-field analysis and noci-ceptive function. Results showed that rat sciatic nerve functional recovery was similar after nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) conduit and autologous nerve grafting. These findings suggest that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) conduit is suitable in use for repair of long-segment sciatic nerve defects.

  16. Guiding intracortical brain tumour cells to an extracortical cytotoxic hydrogel using aligned polymeric nanofibres

    Science.gov (United States)

    Jain, Anjana; Betancur, Martha; Patel, Gaurangkumar D.; Valmikinathan, Chandra M.; Mukhatyar, Vivek J.; Vakharia, Ajit; Pai, S. Balakrishna; Brahma, Barunashish; MacDonald, Tobey J.; Bellamkonda, Ravi V.

    2014-03-01

    Glioblastoma multiforme is an aggressive, invasive brain tumour with a poor survival rate. Available treatments are ineffective and some tumours remain inoperable because of their size or location. The tumours are known to invade and migrate along white matter tracts and blood vessels. Here, we exploit this characteristic of glioblastoma multiforme by engineering aligned polycaprolactone (PCL)-based nanofibres for tumour cells to invade and, hence, guide cells away from the primary tumour site to an extracortical location. This extracortial sink is a cyclopamine drug-conjugated, collagen-based hydrogel. When aligned PCL-nanofibre films in a PCL/polyurethane carrier conduit were inserted in the vicinity of an intracortical human U87MG glioblastoma xenograft, a significant number of human glioblastoma cells migrated along the aligned nanofibre films and underwent apoptosis in the extracortical hydrogel. Tumour volume in the brain was significantly lower following insertion of aligned nanofibre implants compared with the application of smooth fibres or no implants.

  17. Fabrication of YBa2Cu3O7-δ superconducting nanofibres by electrospinning

    Science.gov (United States)

    Cui, Xue Mei; Lyoo, Won Seok; Son, Won Keun; Park, Dae Hun; Choy, Jin Ho; Lee, Taek Seung; Park, Won Ho

    2006-12-01

    YBa2Cu3O7-δ superconducting nanofibres were successfully fabricated via the electrospinning method in combination with the sol-gel process. The solution was prepared by the sol-gel process with a homogeneous aqueous PVA solution containing Y, Ba, and Cu acetates. The viscosity of the precursor sol for electrospinning was controlled by the evaporation of solvent and a condensation reaction. The electrospun nanofibres were pyrolysed to remove PVA or volatile components, and then sintered to generate a superconducting phase. The critical transition temperature (Tc) of superconducting YBa2Cu3O7-δ nanofibres was measured by DC susceptibility tests. By optimizing the electrospinning process and following heat treatments, superconducting YBa2Cu3O7-δ nanofibres with a Tc = 92.2 K could be produced.

  18. Immobilisation of cyclodextrin glucanotransferase into polyvinyl alcohol (PVA nanofibres via electrospinning

    Directory of Open Access Journals (Sweden)

    Suryani Saallah

    2016-06-01

    Full Text Available Immobilisation of cyclodextrin glucanotransferase (CGTase on nanofibres was demonstrated. CGTase solution (1% v/v and PVA (8 wt% solution were mixed followed by electrospinning (−9 kV, 3 h. CGTase/PVA nanofibres with an average diameter of 176 ± 46 nm were successfully produced. The nanofibres that consist of immobilised CGTase were crosslinked with glutaraldehyde vapour. A CGTase/PVA film made up from the same mixture and treated the same way was used as a control experiment. The immobilised CGTase on nanofibres showed superior performance with nearly a 2.5 fold higher enzyme loading and 31% higher enzyme activity in comparison with the film.

  19. Mitochondrial diaphorases as NAD⁺ donors to segments of the citric acid cycle that support substrate-level phosphorylation yielding ATP during respiratory inhibition.

    Science.gov (United States)

    Kiss, Gergely; Konrad, Csaba; Pour-Ghaz, Issa; Mansour, Josef J; Németh, Beáta; Starkov, Anatoly A; Adam-Vizi, Vera; Chinopoulos, Christos

    2014-04-01

    Substrate-level phosphorylation mediated by succinyl-CoA ligase in the mitochondrial matrix produces high-energy phosphates in the absence of oxidative phosphorylation. Furthermore, when the electron transport chain is dysfunctional, provision of succinyl-CoA by the α-ketoglutarate dehydrogenase complex (KGDHC) is crucial for maintaining the function of succinyl-CoA ligase yielding ATP, preventing the adenine nucleotide translocase from reversing. We addressed the source of the NAD(+) supply for KGDHC under anoxic conditions and inhibition of complex I. Using pharmacologic tools and specific substrates and by examining tissues from pigeon liver exhibiting no diaphorase activity, we showed that mitochondrial diaphorases in the mouse liver contribute up to 81% to the NAD(+) pool during respiratory inhibition. Under these conditions, KGDHC's function, essential for the provision of succinyl-CoA to succinyl-CoA ligase, is supported by NAD(+) derived from diaphorases. Through this process, diaphorases contribute to the maintenance of substrate-level phosphorylation during respiratory inhibition, which is manifested in the forward operation of adenine nucleotide translocase. Finally, we show that reoxidation of the reducible substrates for the diaphorases is mediated by complex III of the respiratory chain.

  20. Removal of copper ions from aqueous solution by adsorption onto novel polyelectrolyte film-coated nanofibrous silk fibroin non-wovens

    Science.gov (United States)

    Zhou, Weitao; Huang, Haitao; Du, Shan; Huo, Yingdong; He, Jianxin; Cui, Shizhong

    2015-08-01

    In this approach, polyelectrolyte film-coated nanofibrous silk fibroin (SF) nonwovens were prepared from the alternate deposition of positively charged polyethylenimine (PEI) and negatively charged SF using electrostatic layer-by-layer (LBL) self-assembled technology. The composite membranes were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectrometer. The SF-PEI multilayer-assembled nanofibers (less than five layers) were fine and uniform with the fiber diameter from 400 nm to 600 nm, and had very large surface area and high porosity (more than 70%). The amino groups of PEI were proved to be deposited onto SF nonwovens, which granted the coated nonwovens with potential applicability for copper ions adsorption. The PEI films coated SF substrate showed much higher copper ions adsorption capacity than that of ethanol treated SF nanofibers. Adding the number of PEI coated could enhance the Cu2+ adsorption capacity significantly. The maximum milligrams per gram of copper ions adsorbed reached 59.7 mg/g when the SF substrate was coated with 5 bilayers of SF-PEI. However, the copper ions adsorption capacity had no obvious change as the number of PEI continued to increase. These results suggest potential for PEL film-coated nanofibrous nonwovens as a new adsorbent for metal ions.

  1. Preparation of Mn3O4 Nanofibres via An Electrospinning Technique

    Institute of Scientific and Technical Information of China (English)

    Chang Lu SHAO; Hong Yu GUAN; Shang Bin WEN; Bin CHEN; Xing Hua YANG; Jian GONG

    2004-01-01

    Thin PVA/manganese acetate composite fibres were prepared by using sol-gel processing and electrospinning technique.After calcinations of the above precursor fibres, Mn3O4 nanofibres with a diameter of 50-200 nm could be successfully obtained.The fibres were characterized by SEM,FT-IR,XRD.The results showed that the crystalline phase and morphology of nanofibres were largely influenced by the calcination temperature.

  2. Nanofibrous Scaffolds of Bio-Polyesters: In Vitro and In Vivo Characterizations and Tissue Response

    OpenAIRE

    Tang, Hui Ying; Ishii, Daisuke; Sudesh, Kumar; Yamaoka, Tetsuji; IWATA, Tadahisa

    2010-01-01

    The overall aim of this research was to electrospin P(3HB-co-97mol%-4HB) for fabricating tissue-engineering scaffold with enhanced mechanical properties, bioabsorption and biocompatibility. Its performance as a nanofibrous scaffold for tissue engineering was compared with electrospun homopolymer P(3HB) and its copolymers containing 5mol%3HHx and 7mol%-4HB as well as with electrospun PLA-based scaffolds. All of these nanofibrous scaffolds were implanted subcutaneously in rats to evaluate their...

  3. Crack initiation modes in bilayered alumina/porcelain disks as a function of core/veneer thickness ratio and supporting substrate stiffness.

    Science.gov (United States)

    Wakabayashi, N; Anusavice, K J

    2000-06-01

    We hypothesize that the fracture resistance of alumina core/porcelain veneer disks increases and that crack initiation shifts from veneer to core as the core/veneer thickness ratio (t(C)/t(V)) increases from 0.5/1.0 to 1.3/0.2, or as the elastic modulus of the supporting substrate (E(S)) to which it is resin-bonded increases from 5.1 to 226 GPa. When supported by a low-modulus substrate, disks with low t(C)/t(V) ratios exhibited cracks in the veneer and within the core, while those with high t(C)/t(V) ratios demonstrated core cracks, but not veneer cracks. None of the disks supported by Ni-Cr alloy (E = 226 GPa) exhibited core cracks. These results support the hypothesis that the crack initiation site shifts as the t(C)/t(V) ratio increases, but the increase in E(S) did not affect the crack initiation site. This study suggests that the t(C)/t(V) ratio is the dominant factor that controls the failure initiation site in bilayered ceramic disks.

  4. Preparation of the flexible ZrO{sub 2}/C composite nanofibrous film via electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Xin; Song, Lixin; Xie, Xueyao; Zhou, Yangyang; Guan, Yingli; Xiong, Jie [Zhejiang Sci-Tech University, College of Materials and Textiles, Hangzhou (China); Zhejiang Sci-Tech University, Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Ministry of Education, Hangzhou (China)

    2016-07-15

    The flexible ZrO{sub 2}/C composite nanofibrous film was fabricated by electrospinning and thermal treatment. Field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffractometer, and Fourier transform infrared spectra were used to characterize the morphology and microstructure of the ZrO{sub 2}/C composite nanofibrous film. The ZrO{sub 2}/C nanofibers exhibited rough surface and had the average diameter of about 230 ± 35 nm. And the ZrO{sub 2} nanoparticles were incorporated in carbon matrix and in tetragonal and monoclinic. The flexural property of the ZrO{sub 2}/C composite nanofibrous film was investigated in detail. The results showed that the flexural property of the nanofibrous film was greatly improved with addition of the ZrO{sub 2} nanoparticles. Besides, with the increase of the contents of ZrO{sub 2} nanoparticles, the flexural modulus of the nanofibrous film decreased, reached a lowest value, and then increased. The lowest flexural modulus of the ZrO{sub 2}/C composite nanofibrous film in precursor concentration of 7.0 wt% was 8.55 ± 0.06 MPa. (orig.)

  5. Magnesium Oxide Nanoparticles Reinforced Electrospun Alginate-Based Nanofibrous Scaffolds with Improved Physical Properties

    Science.gov (United States)

    Mantilaka, M. M. M. G. P. G.; Goh, K. L.; Ratnayake, S. P.; Amaratunga, G. A. J.; de Silva, K. M. Nalin

    2017-01-01

    Mechanically robust alginate-based nanofibrous scaffolds were successfully fabricated by electrospinning method to mimic the natural extracellular matrix structure which benefits development and regeneration of tissues. Alginate-based nanofibres were electrospun from an alginate/poly(vinyl alcohol) (PVA) polyelectrolyte complex. SEM images revealed the spinnability of the complex composite nanofibrous scaffolds, showing randomly oriented, ultrafine, and virtually defects-free alginate-based/MgO nanofibrous scaffolds. Here, it is shown that an alginate/PVA complex scaffold, blended with near-spherical MgO nanoparticles (⌀ 45 nm) at a predetermined concentration (10% (w/w)), is electrospinnable to produce a complex composite nanofibrous scaffold with enhanced mechanical stability. For the comparison purpose, chemically cross-linked electrospun alginate-based scaffolds were also fabricated. Tensile test to rupture revealed the significant differences in the tensile strength and elastic modulus among the alginate scaffolds, alginate/MgO scaffolds, and cross-linked alginate scaffolds (P < 0.05). In contrast to cross-linked alginate scaffolds, alginate/MgO scaffolds yielded the highest tensile strength and elastic modulus while preserving the interfibre porosity of the scaffolds. According to the thermogravimetric analysis, MgO reinforced alginate nanofibrous scaffolds exhibited improved thermal stability. These novel alginate-based/MgO scaffolds are economical and versatile and may be further optimised for use as extracellular matrix substitutes for repair and regeneration of tissues. PMID:28694826

  6. Magnesium Oxide Nanoparticles Reinforced Electrospun Alginate-Based Nanofibrous Scaffolds with Improved Physical Properties

    Directory of Open Access Journals (Sweden)

    R. T. De Silva

    2017-01-01

    Full Text Available Mechanically robust alginate-based nanofibrous scaffolds were successfully fabricated by electrospinning method to mimic the natural extracellular matrix structure which benefits development and regeneration of tissues. Alginate-based nanofibres were electrospun from an alginate/poly(vinyl alcohol (PVA polyelectrolyte complex. SEM images revealed the spinnability of the complex composite nanofibrous scaffolds, showing randomly oriented, ultrafine, and virtually defects-free alginate-based/MgO nanofibrous scaffolds. Here, it is shown that an alginate/PVA complex scaffold, blended with near-spherical MgO nanoparticles (⌀ 45 nm at a predetermined concentration (10% (w/w, is electrospinnable to produce a complex composite nanofibrous scaffold with enhanced mechanical stability. For the comparison purpose, chemically cross-linked electrospun alginate-based scaffolds were also fabricated. Tensile test to rupture revealed the significant differences in the tensile strength and elastic modulus among the alginate scaffolds, alginate/MgO scaffolds, and cross-linked alginate scaffolds (P<0.05. In contrast to cross-linked alginate scaffolds, alginate/MgO scaffolds yielded the highest tensile strength and elastic modulus while preserving the interfibre porosity of the scaffolds. According to the thermogravimetric analysis, MgO reinforced alginate nanofibrous scaffolds exhibited improved thermal stability. These novel alginate-based/MgO scaffolds are economical and versatile and may be further optimised for use as extracellular matrix substitutes for repair and regeneration of tissues.

  7. Controlled release of doxorubicin from electrospun PEO/chitosan/graphene oxide nanocomposite nanofibrous scaffolds.

    Science.gov (United States)

    Ardeshirzadeh, Behnaz; Anaraki, Nadia Aboutalebi; Irani, Mohammad; Rad, Leila Roshanfekr; Shamshiri, Soodeh

    2015-03-01

    Polyethylene oxide (PEO)/chitosan (CS)/graphene oxide (GO) electrospun nanofibrous scaffolds were successfully developed via electrospinning process for controlled release of doxorubicin (DOX). The SEM analysis of nanofibrous scaffolds with different contents of GO (0.1, 0.2, 0.5 and 0.7wt.%) indicated that the minimum diameter of nanofibers was found to be 85nm for PEO/CS/GO 0.5% nanofibers. The π-π stacking interaction between DOX and GO with fine pores of nanofibrous scaffolds exhibited higher drug loading (98%) and controlled release of the DOX loaded PEO/CS/GO nanofibers. The results of DOX release from nanofibrous scaffolds at pH5.3 and 7.4 indicated strong pH dependence. The hydrogen bonding interaction between GO and DOX could be unstable under acidic conditions which resulted in faster drug release rate in pH5.3. The cell viability results indicated that DOX loaded PEO/CS/GO/DOX nanofibrous scaffold could be used as an alternative source of DOX compared with free DOX to avoid the side effects of free DOX. Thus, the prepared nanofibrous scaffold offers as a novel formulation for treatment of lung cancer.

  8. Polycaprolactone and polycaprolactone/chitosan nanofibres functionalised with the pH-sensitive dye Nitrazine Yellow.

    Science.gov (United States)

    Van der Schueren, Lien; De Meyer, Thierry; Steyaert, Iline; Ceylan, Özgür; Hemelsoet, Karen; Van Speybroeck, Veronique; De Clerck, Karen

    2013-01-02

    Nanofibres functionalised with pH-sensitive dyes could greatly contribute to the development of stimuli-responsive materials. However, the application of biocompatible polymers is vital to allow for their use in (bio)medical applications. Therefore, this paper focuses on the development and characterisation of pH-sensitive polycaprolactone (PCL) nanofibrous structures and PCL/chitosan nanofibrous blends with 20% chitosan. Electrospinning with added Nitrazine Yellow molecules proved to be an excellent method resulting in pH-responsive non-wovens. Unlike the slow and broad response of PCL nanofibres (time lag of more than 3h), the use of blends with chitosan led to an increased sensitivity and significantly reduced response time (time lag of 5 min). These important effects are attributed to the increased hydrophilic nature of the nanofibres containing chitosan. Computational calculations indicated stronger interactions, mainly based on electrostatic interactions, of the dye with chitosan (ΔG of -132.3 kJ/mol) compared to the long-range interactions with PCL (ΔG of -35.6 kJ/mol), thus underpinning our experimental observations. In conclusion, because of the unique characteristics of chitosan, the use of PCL/chitosan blends in pH-sensitive biocompatible nanofibrous sensors is crucial.

  9. Application of avidin-biotin technology to improve cell adhesion on nanofibrous matrices.

    Science.gov (United States)

    Pan, Jian-feng; Liu, Ning-hua; Shu, Lin-yuan; Sun, Hui

    2015-05-16

    Electrospinning is an easy and effective technique to produce submicron fibers possessing a range of attractive characteristics such as interconnected porous structures similar to natural ECM and good resilience to movement. Rapid and efficient cell attachment to nanofibrous matrices is a necessary prerequisite in tissue engineering. Thus, the aim of this study is to evaluate poly(ε-caprolactone-co-lactide)/Pluronic (PLCL/Pluronic) nanofibrous matrices with avidin-biotin technology for improving cell adhesion for the first time. PLCL/Pluronic nanofibers had relatively homogeneous fibers and interconnected porous structures. Pluronic significantly modified the hydrophilicity of nanofibrous matrices and PLCL/Pluronic nanofibrous matrices had better performance on maintaining cell proliferation. Avidin-biotin technology had no negative effect on the hydrophilic property, mechanical property and cell proliferation. Meanwhile, the attachment and spreading of adipose-derived stem cells (ADSCs) onto PLCL/Pluronic nanofibrous matrices with avidin-biotin technology was promoted obviously. PLCL/Pluronic nanofibrous matrices inheriting the excellent characteristics of both PLCL and Pluronic have the better cell adhesion ability through avidin-biotin technology, implying a promising application in skin care, tissue regeneration and other related area.

  10. Electrospun TiO2 nanofibre-based gas sensors fabricated by AC electrophoresis deposition

    Indian Academy of Sciences (India)

    E Z Karimi; J Esmaeilzadeh; E Marzbanrad

    2015-02-01

    In this paper, gas sensing properties of the sensor based on titanium dioxide (TiO2) nanofibres are reported. These nanofibres were synthesized through electrospinning of polyvinyl pyrrolidone (PVP) / titanium tetra isopropoxide. Calcination of the obtained amorphous PVP/TiO2 nanofibres resulted in nanofibres of TiO2 with the same morphology. In this step, scanning electron microscopy and X-ray diffraction were applied in order to analyse these nanofibres. Then, nanofibres of TiO2 were deposited selectively by AC electrophoretic deposition on interdigitated electrodes and exposed to different concentrations of NO2 (8–50 p.p.m.) at 450–550°C. Gas sensing measurements illustrated that this sensor had adequate response to target gas at 450°C. The maximum response of gas sensors, (the ratio of sensor resistances $S = R_{\\text{gas}}/R_{\\text{N2}}$), achieved was around 30 for 50 p.p.m. NO2 at 450°C.

  11. A novel biofuel cell based on electrospun collagen-carbon nanotube nanofibres.

    Science.gov (United States)

    Zheng, W; Ma, J Y; Guo, F; Li, J; Zhou, H M; Xu, X X; Li, L; Zheng, Y F

    2014-01-01

    The paper demonstrates a novel glucose/O2 biofuel cell (BFC) based on the electrospun collagen-SWNTs nanofibres with the glucose oxidase (GOD) as the anodic biocatalysts and the laccase as the cathodic biocatalysts. With an average diameter of about (260±95) nm, the electrospun collagen-SWNTs nanofibres exhibited smooth surfaces. The collagen-SWNTs nanofibres modified electrode showed good electron transfer behavior, because of the properties of SWNTs and the three-dimensional reticular structure of the electrospun nanofibers. The GOD and laccase, immobilized in the collagen-SWNTs nanofibres, exhibited good catalytic activity towards glucose oxidation and oxygen reduction through mediators of ferrocene monocarboxylic acid (FMCA) and 2,2'-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt (ABTS), respectively. The maximum power density of the assembled glucose/O2 BFC based on the electrospun collagen-SWNTs nanofibres was ca. 14.3 μW/cm2. Moreover, more than 50% of the initial value remained after continuous operation of 100 h. The results indicated the potential to apply the electrospun collagen-SWNTs nanofibres for novel BFC device.

  12. Development of insulating substrates for multilayer thermoelectric devices; Elaboration d'elements de support dans des dispositifs thermoelectriques multicouches

    Energy Technology Data Exchange (ETDEWEB)

    Kadiebu Kandolo, St.

    2005-10-15

    The design and fabrication of a high performance thermoelectric generator based on ceramic technology is envisaged. The system consists of n and p-type semi-conducting layers deposited on a thermally insulating dielectric substrate. The present work is devoted to the choice and preparation of the material for the substrate. The desired characteristics for a low thermal conductivity are an amorphous solid with a porous microstructure. Two raw materials were selected as candidates. The first is a clay, made of layered minerals for which de-hydroxylation at 600 deg. C leads to a disordered structure and the second is diatomite, a material constituted of amorphous silica with and inherent natural porosity inside plate like grains. Sintering the clay at 800 deg. C yields a material with thermal conductivity of 0.21 W/m.K at room temperature increasing to 0.26 W/m.K at 600 deg. C. In an attempt to decrease the thermal conductivity, the clay was mixed with fine amorphous silica or zircon. The zircon based mixture was the most effective giving a thermal conductivity of 0.19 W/m.K which remains constant with temperature. In addition to a low thermal conductivity, diatomite presents another interesting advantage. First, tape casting was used to obtain porous layers yielding a thermal conductivity as low as 0.08 W/m.K at room temperature. Then it was found that under certain preparation conditions, the tape cast diatomite formed with a thin dense layer at the surface. This facilitates deposition of the active semi-conductor layer by avoiding loss from penetration through the open porosity of the substrate. (author)

  13. Photocatalytic H{sub 2} production with CdS-based catalysts from a sulphide/sulphite substrate: an effort to develop MgO-supported catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Subrahmanyam, M.; Supriya, V.T.; Reddy, P.R. [Indian Inst. of Chemical Technology, Hyderabad (India). Catalysis Section

    1996-02-01

    CdS-based photocatalysts supported on MgO and {gamma}-Al{sub 2}O{sub 3} have been prepared, characterized and tested for dihydrogen evolution from a sulphide/sulphite substrate using a halogen lamp source. The effect of precursor salt for CdS preparation, the optimum loading of CdS on the support and the concentration of the catalyst in 50 ml of solution have been investigated. The effect of adding to CdS a semiconductor ZnS-Ag{sub 2}S and catalytic materials like Pt and RuO{sub 2} have also been studied. The results obtained from the basic nature of MgO support are compared with the acidic nature of Al{sub 2}O{sub 3} support. The importance of the acid-base properties of the support is substantiated by modifying the Al{sub 2}O{sub 3} support with base materials like CaO/BaO. Thus, the effect of the acid-base properties of the supports is highlighted. (author)

  14. Substrate-supported large-band-gap quantum spin Hall insulator based on III-V bismuth layers

    Science.gov (United States)

    Padilha, J. E.; Janotti, A.; Fazzio, A.; da Silva, A. J. R.

    2016-11-01

    We show that III-V bismuth-based two-dimensional (2D) materials grown on an anion-terminated SrTe (111) substrate are 2D topological insulators. The III-Bi layers exhibit large nontrivial band gaps, ranging from 0.15 to 0.72 eV, depending on the passivation on the top surface, i.e., using hydrogen or halogens. We find that Γ -centered Dirac helical states, protected by time-reversal symmetry, appear at the edges of nanoribbon structures made of III-Bi layers on the SrTe substrate. The nontrivial character of the band gap is also determined by calculations of the Z2 invariant. We also find that the topological phase is maintained in the ultrathin quantum well heterostructures SrTe/III-Bi/SrTe, i.e., when the 2D materials are sandwiched between SrTe along the [111] direction, opening a new route for the fabrication of nanostructured devices based on 2D quantum spin Hall insulators.

  15. Study on deposition technique and properties of Pd/Ag alloy film sensor supported on ceramic substrate

    Science.gov (United States)

    Geng, Z. T.; He, Q.; Jin, C. G.

    2016-07-01

    Developing high-quality hydrogen sensitive material is the core part of hydrogen sensor, whose performance is determined by the sensitive response, reproducibility and recovery of hydrogen material etc. In order to overcome the defects of hydrogen embrittlement in previous hydrogen sensor which were based on the pure palladium, sliver as the second component added to the palladium was studied. Using photochemical etching technology to produce a bent metal mask, the mask is put on the ceramic substrate. Firstly, the thin film of Ta2O5 as a transition layer grew on the ceramic substrate. Then, a series of Pd/Ag alloy film sensors were prepared, and each performance characterization of Pd/Ag alloy film was studied. Testing results indicated that the thin film had a good linear output performance at 0∼⃒30% hydrogen concentration range, and demonstrates a high responsiveness and good repeatability. With temperature increasing, the strength of the responsive signal of the Pd/Ag alloy film decreases and its responsive time was also shortened.

  16. Role of surfactant-mediated electrodeposited titanium oxide substrate in improving electrocatalytic features of supported platinum particles

    Energy Technology Data Exchange (ETDEWEB)

    Spătaru, Tanţa; Preda, Loredana; Osiceanu, Petre; Munteanu, Cornel; Anastasescu, Mihai; Marcu, Maria; Spătaru, Nicolae, E-mail: nspataru@icf.ro

    2014-01-01

    A new hybrid system with improved photocatalytic and electrocatalytic performances was obtained by two-step potentiostatic deposition on highly boron-doped diamond (BDD) substrate. First, hydrated TiO{sub 2} was anodically deposited from a TiCl{sub 3} aqueous solution, both in the presence and in the absence of sodium dodecyl sulfate (SDS). The study of the UV irradiation effect evidenced that titanium oxide coatings obtained by surfactant-assisted electrodeposition (TiO{sub 2}:SDS) exhibit enhanced photocurrent, due to its very rough texonsture and presumably to better efficiency of charge carrier separation. Electrochemical deposition of platinum on the oxide-coated BDD was carried out in a second step and AFM, SEM and XPS measurements have shown that, on the TiO{sub 2}:SDS substrate, Pt particles are smaller, more uniformly distributed, and tend to form clusters, leading to a specific surface area of the electrocatalyst of ca. 6.55 m{sup 2} g{sup −1}. Carbon monoxide stripping experiments demonstrated that, when deposited on TiO{sub 2}:SDS, Pt particles are also less sensitive to CO-poisoning during methanol anodic oxidation.

  17. Encapsulation of bacteria and viruses in electrospun nanofibres

    Science.gov (United States)

    Salalha, W.; Kuhn, J.; Dror, Y.; Zussman, E.

    2006-09-01

    Bacteria and viruses were encapsulated in electrospun polymer nanofibres. The bacteria and viruses were suspended in a solution of poly(vinyl alcohol) (PVA) in water and subjected to an electrostatic field of the order of 1 kV cm-1. Encapsulated bacteria in this work, (Escherichia coli, Staphylococcus albus) and bacterial viruses (T7, T4, λ) managed to survive the electrospinning process while maintaining their viability at fairly high levels. Subsequently the bacteria and viruses remain viable during three months at -20 and -55 °C without a further decrease in number. The present results demonstrate the potential of the electrospinning process for the encapsulation and immobilization of living biological material.

  18. Encapsulation of bacteria and viruses in electrospun nanofibres

    Energy Technology Data Exchange (ETDEWEB)

    Salalha, W [Faculty of Mechanical Engineering, Technion, Israel Institute of Technology, Haifa 32000 (Israel); Kuhn, J [Faculty of Biology, Technion, Israel Institute of Technology, Haifa 32000 (Israel); Dror, Y [Faculty of Mechanical Engineering, Technion, Israel Institute of Technology, Haifa 32000 (Israel); Zussman, E [Faculty of Mechanical Engineering, Technion, Israel Institute of Technology, Haifa 32000 (Israel)

    2006-09-28

    Bacteria and viruses were encapsulated in electrospun polymer nanofibres. The bacteria and viruses were suspended in a solution of poly(vinyl alcohol) (PVA) in water and subjected to an electrostatic field of the order of 1 kV cm{sup -1}. Encapsulated bacteria in this work (Escherichia coli, Staphylococcus albus) and bacterial viruses (T7, T4, {lambda}) managed to survive the electrospinning process while maintaining their viability at fairly high levels. Subsequently the bacteria and viruses remain viable during three months at -20 and -55 deg. C without a further decrease in number. The present results demonstrate the potential of the electrospinning process for the encapsulation and immobilization of living biological material.

  19. Fabrication of Silk Nanofibres with Needle and Roller Electrospinning Methods

    Directory of Open Access Journals (Sweden)

    Nongnut Sasithorn

    2014-01-01

    Full Text Available In this study, silk nanofibres were prepared by electrospinning from silk fibroin in a mixture of formic acid and calcium chloride. A needle and a rotating cylinder were used as fibre generators in the spinning process. The influences of the spinning electrode and spinning parameters (silk concentration and applied voltage on the spinning process, morphology of the obtained fibres, and the production rate of the spinning process were examined. The concentration of the spinning solution influenced the diameter of the silk electrospun fibres, with an increase in the concentration increasing the diameters of the fibres in both spinning systems. The diameters of the electrospun fibres produced by roller electrospinning were greater than those produced by needle electrospinning. Moreover, increasing the concentration of the silk solution and the applied voltage in the spinning process improved the production rate in roller electrospinning but had less influence on the production rate in needle electrospinning.

  20. Hemocompatible surface of electrospun nanofibrous scaffolds by ATRP modification.

    Science.gov (United States)

    Yuan, Wenjie; Feng, Yakai; Wang, Heyun; Yang, Dazhi; An, Bo; Zhang, Wencheng; Khan, Musammir; Guo, Jintang

    2013-10-01

    The electrospun scaffolds are potential application in vascular tissue engineering since they can mimic the nano-sized dimension of natural extracellular matrix (ECM). We prepared a fibrous scaffold from polycarbonateurethane (PCU) by electrospinning technology. In order to improve the hydrophilicity and hemocompatibility of the fibrous scaffold, poly(ethylene glycol) methacrylate (PEGMA) was grafted onto the fiber surface by surface-initiated atom transfer radical polymerization (SI-ATRP) method. Although SI-ATRP has been developed and used for surface modification for many years, there are only few studies about the modification of electrospun fiber by this method. The modified fibrous scaffolds were characterized by SEM, Fourier transform infrared (FTIR), and X-ray photoelectron spectroscopy (XPS). The scaffold morphology showed no significant difference when PEGMA was grafted onto the scaffold surface. Based on the water contact angle measurement, the surface hydrophilicity of the scaffold surface was improved significantly after grafting hydrophilic PEGMA (P=0.0012). The modified surface showed effective resistance for platelet adhesion compared with the unmodified surface. Activated partial thromboplastin time (APTT) of the PCU-g-PEGMA scaffold was much longer than that of the unmodified PCU scaffold. The cyto-compatibility of electrospun nanofibrous scaffolds was tested by human umbilical vein endothelial cells (HUVECs). The images of 7-day cultured cells on the scaffold surface were observed by SEM. The modified scaffolds showed high tendency to induce cell adhesion. Moreover, the cells reached out pseudopodia along the fibrous direction and formed a continuous monolayer. Hemolysis test showed that the grafted chains of PEGMA reduced blood coagulation. These results indicated that the modified electrospun nanofibrous scaffolds were potential application as artificial blood vessels.

  1. A sound absorptive element comprising an acoustic resonance nanofibrous membrane.

    Science.gov (United States)

    Kalinova, Klara

    2015-01-01

    As absorption of sound of lower frequencies is quite problematic with fibrous material made up of coarser fibers, development of highly efficient sound absorption material is called for. This is why this work deals with the development of new high sound absorption material. To absorb the low frequencies, especially the structures based on resonance principle of nanofibrous layers are used, when through resonance of some elements the acoustic energy is transferred into thermal energy. The goal of the invention is achieved by a sound absorbing means which contains resonance membrane formed by a layer of polymeric nanofibers, which is attached to a frame. For production of nanofibrous membranes, the cord electrospinning was used. The resonance membrane was then, upon impact of sound waves of low frequency, brought into forced vibrations, whereby the kinetic energy of the membrane was converted into thermal energy by friction of individual nanofibers, by the friction of the membrane with ambient air and possibly with other layers of material arranged in its proximity, and some of the energy was also transmitted to the frame, through which the vibrations of the resonance membrane were damped. The density and shape of the mesh of frame formations determine the resonance frequency of the acoustic means. The goal of the invention is therefore to eliminate or at least reduce the disadvantages of the present state of the art and to propose sound absorbing means that would be capable of absorbing, with good results sounds in as broadest frequency range as possible. Here, we also discussed some patents relevant to the topic.

  2. Intelligent thermoresponsive substrate from modified overhead projection sheet as a tool for construction and support of cell sheets in vitro.

    Science.gov (United States)

    Nithya, Joseph; Kumar, P R Anil; Tilak, Prasad; Leena, Joseph; Sreenivasan, K; Kumary, T V

    2011-02-01

    Cell sheet engineering using thermoresponsive culture dishes allows harvesting of intact in vitro cell sheet. In this study, commercially available polyethylene terephthalate-based overhead projection transparency sheet (OHPS) was identified as a substrate for coating thermoresponsive poly(N-isopropylacrylamide-co-glycidylmethacrylate) (NGMA) copolymer having lower critical solution temperature of 28°C. Since OHPS is highly hydrophobic and rigid, the surface was modified by alkali treatment (OHPS-M) to functionalize the surface with carboxyl and hydroxyl groups so as to make it more suitable for efficient coating of NGMA copolymer and cell culture. To impart thermoresponsiveness, OHPS-M was coated with NGMA (OHPS-MC). Surface morphology, surface chemistry, and thermoresponsive coating were analyzed by profilometry, scanning electron microscopy, water contact angle, and Fourier transform infrared spectroscopy. The cytotoxicity, cell adhesion, and proliferation on OHPS-M and OHPS-MC were analyzed using L929 cells. Specific cytocompatibility analysis was done using SIRC (Rabbit corneal) cells. Data revealed cytocompatible nature of OHPS-M and OHPS-MC. Suitability of OHPS-MC for cell sheet harvest and transfer efficiency was assessed using primary corneal cells. Corneal cell sheet constructs retrieved by temperature variation was characterized by reverse transcriptase polymerase chain reaction for markers specific to differentiated corneal cells (keratin 3 and keratin 12) and proliferating cell nuclear antigen, and assessed for viability using fluorescein diacetate staining, tissue architecture by scanning electron microscopy, and cell-cell contacts by connexin-43 staining. The retrieved cell sheets retained corneal epithelial characteristics such as keratin 3/12, viability, and tissue architecture with intact cell-cell contacts as in native tissue. The results proved that surface modification and coating with NGMA on OHPS offer a novel biocompatible thermosensitive

  3. Pulp regeneration in a full-length human tooth root using a hierarchical nanofibrous microsphere system.

    Science.gov (United States)

    Li, Xiangwei; Ma, Chi; Xie, Xiaohua; Sun, Hongchen; Liu, Xiaohua

    2016-04-15

    While pulp regeneration using tissue engineering strategy has been explored for over a decade, successful regeneration of pulp tissues in a full-length human root with a one-end seal that truly simulates clinical endodontic treatment has not been achieved. To address this challenge, we designed and synthesized a unique hierarchical growth factor-loaded nanofibrous microsphere scaffolding system. In this system, vascular endothelial growth factor (VEGF) binds with heparin and is encapsulated in heparin-conjugated gelatin nanospheres, which are further immobilized in the nanofibers of an injectable poly(l-lactic acid) (PLLA) microsphere. This hierarchical microsphere system not only protects the VEGF from denaturation and degradation, but also provides excellent control of its sustained release. In addition, the nanofibrous PLLA microsphere integrates the extracellular matrix-mimicking architecture with a highly porous injectable form, efficiently accommodating dental pulp stem cells (DPSCs) and supporting their proliferation and pulp tissue formation. Our in vivo study showed the successful regeneration of pulp-like tissues that fulfilled the entire apical and middle thirds and reached the coronal third of the full-length root canal. In addition, a large number of blood vessels were regenerated throughout the canal. For the first time, our work demonstrates the success of pulp tissue regeneration in a full-length root canal, making it a significant step toward regenerative endodontics. The regeneration of pulp tissues in a full-length tooth root canal has been one of the greatest challenges in the field of regenerative endodontics, and one of the biggest barriers for its clinical application. In this study, we developed a unique approach to tackle this challenge, and for the first time, we successfully regenerated living pulp tissues in a full-length root canal, making it a significant step toward regenerative endodontics. This study will make positive scientific

  4. Aqueous-Phase Preparation of Model HDS Catalysts on Planar Alumina Substrates: Support Effect on Mo Adsorption and Sulfidation.

    Science.gov (United States)

    Bara, Cédric; Plais, Lucie; Larmier, Kim; Devers, Elodie; Digne, Mathieu; Lamic-Humblot, Anne-Félicie; Pirngruber, Gerhard D; Carrier, Xavier

    2015-12-23

    The role of the oxide support on the structure of the MoS2 active phase (size, morphology, orientation, sulfidation ratio, etc.) remains an open question in hydrotreating catalysis and biomass processing with important industrial implications for the design of improved catalytic formulations. The present work builds on an aqueous-phase surface-science approach using four well-defined α-alumina single crystal surfaces (C (0001), A (112̅0), M (101̅0), and R (11̅02) planes) as surrogates for γ-alumina (the industrial support) in order to discriminate the specific role of individual support facets. The reactivity of the various surface orientations toward molybdenum adsorption is controlled by the speciation of surface hydroxyls that determines the surface charge at the oxide/water interface. The C (0001) plane is inert, and the R (11̅02) plane has a limited Mo adsorption capacity while the A (112̅0) and M (101̅0) surfaces are highly reactive. Sulfidation of model catalysts reveals the highest sulfidation degree for the A (112̅0) and M (101̅0) planes suggesting weak metal/support interactions. Conversely, a low sulfidation rate and shorter MoS2 slabs are found for the R (11̅02) plane implying stronger Mo-O-Al bonds. These limiting cases are reminiscent of type I/type II MoS2 nanostructures. Structural analogies between α- and γ- alumina surfaces allow us to bridge the material gap with real Al2O3-supported catalysts. Hence, it can be proposed that Mo distribution and sulfidation rate are heterogeneous and surface-dependent on industrial γ-Al2O3-supported high-surface-area catalysts. These results demonstrate that a proper control of the γ-alumina morphology is a strategic lever for a molecular-scale design of hydrotreating catalysts.

  5. Use of scanning electron microscopy to monitor nanofibre/cell interaction in digestive epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Millaku, Agron, E-mail: agron.mi@hotmail.com [Limnos-Company for Applied Ecology Ltd, Podlimbarskega 31, 1000 Ljubljana (Slovenia); Drobne, Damjana [University of Ljubljana, Biotechnical Faculty, Department of Biology, Večna pot 111, 1000 Ljubljana (Slovenia); Centre of Excellence, Advanced Materials and Technologies for the Future (CO NAMASTE), Jamova cesta 39, 1000 Ljubljana (Slovenia); Centre of Excellence, Nanoscience and Nanotechnology (Nanocentre), Jamova cesta 39, 1000 Ljubljana (Slovenia); Torkar, Matjaz [Institute of Metals and Technology IMT, Lepi pot 11, 1000 Ljubljana (Slovenia); Jožef Stefan Institute, Condensed Matter Physics Department, Jamova cesta 39, 1000 Ljubljana (Slovenia); Novak, Sara [University of Ljubljana, Biotechnical Faculty, Department of Biology, Večna pot 111, 1000 Ljubljana (Slovenia); Remškar, Maja [Jožef Stefan Institute, Condensed Matter Physics Department, Jamova cesta 39, 1000 Ljubljana (Slovenia); Pipan-Tkalec, Živa [University of Ljubljana, Biotechnical Faculty, Department of Biology, Večna pot 111, 1000 Ljubljana (Slovenia)

    2013-09-15

    Graphical abstract: Scanning electron microscopy is particularly well suited to the observation of nanofibre/cell interaction in the endothelial cells lining the hepatopancreas. (a) Tungsten oxide nanofibres, (b) test organism Porcellio scaber and schematic appearance of digestive tubes, (c) digestive tube (hepatopancreas) prepared for SEM investigation, (d) digestive gland cells (C) with nanofibres (NF) embedded in the cell membrane and (e) nanofibres inserted deeply in the cells and damaged nanofibres due to peristalsis. -- Highlights: • Tungsten oxide nanofibres react physically with digestive gland epithelial cells in Porcellio scaber. • Physical peristaltic forces of lead to insertion of nanofibres into the cells. • No toxic responses as measured by conventional toxicity biomarkers were detected. • Physical interactions were observed in a majority of the investigated animals. -- Abstract: We provide data obtained by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) on the interaction of ingested tungsten nanofibers with epithelial cells of the digestive tubes of a test organism Porcellio scaber. Conventional toxicity endpoints including feeding behaviour, weight loss and mortality were also measured in each investigated animal. No toxicity was detected in any of exposed animals after 14 days of feeding on tungsten nanofiber dosed food, but when nanofibers enter the digestive system they can react with epithelial cells of the digestive tubes, becoming physically inserted into the cells. In this way, nanofibers can injure the epithelial cells of digestive gland tubes when they are ingested with food. Our SEM data suggest that peristaltic forces may have an important role, not predicted by in vitro experiments, in the interactions of nanomaterials with digestive intestinal cells.

  6. Skeletal muscle regeneration via engineered tissue culture over electrospun nanofibrous chitosan/PVA scaffold.

    Science.gov (United States)

    Kheradmandi, Mahsa; Vasheghani-Farahani, Ebrahim; Ghiaseddin, Ali; Ganji, Fariba

    2016-07-01

    Skeletal muscle tissue shows a remarkable potential in regeneration of injured tissue. However, in some of chronic and volumetric muscle damages, the native tissue is incapable to repair and remodeling the trauma. In the same condition, stem-cell therapy increased regeneration in situations of deficient muscle repair, but the major problem seems to be the lack of ability to attachment and survive of injected cells on the exact location. In this study, chitosan/poly(vinyl alcohol) nanofibrous scaffold was studied to promote cell attachment and provide mechanical support during regeneration. Scaffold was characterized using scanning electron microscope, X-ray diffraction, and tensile test. Degradation and swelling behavior of scaffold were studied for 20 days. The cell-scaffold interaction was characterized by MTT assay for 10 days and in vivo biocompatibility of scaffold in a rabbit model was evaluated. Results showed that cells had a good viability, adhesion, growth, and spread on the scaffold, which make this mat a desirable engineered muscular graft. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1720-1727, 2016.

  7. Dynamic Mechanical and Nanofibrous Topological Combinatory Cues Designed for Periodontal Ligament Engineering.

    Science.gov (United States)

    Kim, Joong-Hyun; Kang, Min Sil; Eltohamy, Mohamed; Kim, Tae-Hyun; Kim, Hae-Won

    2016-01-01

    Complete reconstruction of damaged periodontal pockets, particularly regeneration of periodontal ligament (PDL) has been a significant challenge in dentistry. Tissue engineering approach utilizing PDL stem cells and scaffolding matrices offers great opportunity to this, and applying physical and mechanical cues mimicking native tissue conditions are of special importance. Here we approach to regenerate periodontal tissues by engineering PDL cells supported on a nanofibrous scaffold under a mechanical-stressed condition. PDL stem cells isolated from rats were seeded on an electrospun polycaprolactone/gelatin directionally-oriented nanofiber membrane and dynamic mechanical stress was applied to the cell/nanofiber construct, providing nanotopological and mechanical combined cues. Cells recognized the nanofiber orientation, aligning in parallel, and the mechanical stress increased the cell alignment. Importantly, the cells cultured on the oriented nanofiber combined with the mechanical stress produced significantly stimulated PDL specific markers, including periostin and tenascin with simultaneous down-regulation of osteogenesis, demonstrating the roles of topological and mechanical cues in altering phenotypic change in PDL cells. Tissue compatibility of the tissue-engineered constructs was confirmed in rat subcutaneous sites. Furthermore, in vivo regeneration of PDL and alveolar bone tissues was examined under the rat premaxillary periodontal defect models. The cell/nanofiber constructs engineered under mechanical stress showed sound integration into tissue defects and the regenerated bone volume and area were significantly improved. This study provides an effective tissue engineering approach for periodontal regeneration-culturing PDL stem cells with combinatory cues of oriented nanotopology and dynamic mechanical stretch.

  8. Production characteristics of the "higher plants-soil-like substrate" system as an element of the bioregenerative life support system

    Science.gov (United States)

    Velichko, V. V.; Tikhomirov, A. A.; Ushakova, S. A.; Tikhomirova, N. A.; Shihov, V. N.; Tirranen, L. S.; Gribovskaya, I. A.

    2013-01-01

    The study addresses the possibility of long-duration operation of a higher plant conveyor, using a soil-like substrate (SLS) as the root zone. Chufa (Cyperus esculentus L.), radish (Raphanus sativus L.), and lettuce (Lactuca sativa L.) were used as study material. A chufa community consisting of 4 age groups and radish and lettuce communities consisting of 2 age groups were irrigated with a nutrient solution, which contained mineral elements extracted from the SLS. After each harvest, inedible biomass of the harvested plants and inedible biomasses of wheat and saltwort were added to the SLS. The amounts of the inedible biomasses of wheat and saltwort to be added to the SLS were determined based on the nitrogen content of the edible mass of harvested plants. CO2 concentration in the growth chamber was maintained within the range of 1100-1700 ppm. The results of the study show that higher plants can be grown quite successfully using the proposed process of plant waste utilization in the SLS. The addition of chufa inedible biomass to the SLS resulted in species-specific inhibition of growth of both cultivated crops and microorganisms in the "higher plants - SLS" system. There were certain differences between the amounts of some mineral elements removed from the SLS with the harvested edible biomass and those added to it with the inedible biomasses of wheat and saltwort.

  9. Fabrication of nanofibrous A- or B-sites substituted LaCoO{sub 3} perovskites with macroscopic structures and their catalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Qiang, E-mail: qiangwu@shiep.edu.cn [College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Zhao, Li [College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Wu, Meixia [Department of Chemistry, Shanxi Datong University, Datong 037009 (China); Yao, Weifeng; Qi, Meixue [College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090 (China); Shi, Xiaoyan [State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084 (China); Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

    2014-03-01

    Graphical abstract: Fabrication of nanofibrous La{sub 1−x}Ce{sub x}CoO{sub 3} (x = 0.05, 0.1, 0.2) and LaMn{sub x}Co{sub 1−x}O{sub 3} (x = 0.2, 0.5, 0.8) perovskite-type oxides with macroscopic structures can be successfully achieved by using carbon nanofibers (CNFs) as templates. Furthermore, their application for the combustion of carbon black (CB), which is a model of particulate matter exhausted from diesel engines, was demonstrated. - Highlights: • Nanofibrous perovskites with macroscopic shapes were successfully obtained. • CNFs template method used here is facile, effective and reproducible. • This method might be applicable to other novel material fabrication. • The obtained materials show superior catalytic activity in soot combustion. - Abstract: Fabrication of nanofibrous La{sub 1−x}Ce{sub x}CoO{sub 3} (x = 0.05, 0.1, 0.2) and LaMn{sub x}Co{sub 1−x}O{sub 3} (x = 0.2, 0.5, 0.8) perovskite-type oxides with macroscopic structures can be successfully achieved by using carbon nanofibers (CNFs) as templates. Field emission scanning electron microscopy (FE-SEM), coupled with X-ray diffraction (XRD) analysis confirmed the template effect and formation of the perovskite-type oxides on the macroscopic substrate. It turned out that this facile method can ensure the desired single-phase perovskite-type oxides formation by controlling the corresponding metal ratio during the preparation procedure. In addition, the immobilized nanofibrous La{sub 1−x}Ce{sub x}CoO{sub 3} (x = 0.05) and LaMn{sub x}Co{sub 1−x}O{sub 3} (x = 0.5) perovskite-type oxides can greatly decrease the combustion temperature of nanosized carbon black particles, which has the high potential application prospects in the treatment of diesel soot particles.

  10. Mesophilic hydrogen production in acidogenic packed-bed reactors (APBR) using raw sugarcane vinasse as substrate: Influence of support materials.

    Science.gov (United States)

    Nunes Ferraz Júnior, Antônio Djalma; Etchebehere, Claudia; Zaiat, Marcelo

    2015-08-01

    Bio-hydrogen production from sugarcane vinasse in anaerobic up-flow packed-bed reactors (APBR) was evaluated. Four types of support materials, expanded clay (EC), charcoal (Ch), porous ceramic (PC), and low-density polyethylene (LDP) were tested as support for biomass attachment. APBR (working volume - 2.3 L) were operated in parallel at a hydraulic retention time of 24 h, an organic loading rate of 36.2 kg-COD m(-3) d(-1), at 25 °C. Maximum volumetric hydrogen production values of 509.5, 404, 81.4 and 10.3 mL-H2 d(-1) L(-1)reactor and maximum yields of 3.2, 2.6, 0.4 and 0.05 mol-H2 mol(-1) carbohydrates total, were observed during the monitoring of the reactors filled with LDP, EC, Ch and PC, respectively. Thus, indicating the strong influence of the support material on H2 production. LDP was the most appropriate material for hydrogen production among the materials evaluated. 16S rRNA gene by Terminal Restriction Fragment Length Polymorphism (T-RFLP) analysis and scanning electron microscopy confirmed the selection of different microbial populations. 454-pyrosequencing performed on samples from APBR filled with LDP revealed the presence of hydrogen-producing organisms (Clostridium and Pectinatus), lactic acid bacteria and non-fermentative organisms.

  11. Enhanced osteogenic differentiation of mesenchymal stem cells on poly(L-lactide) nanofibrous scaffolds containing carbon nanomaterials.

    Science.gov (United States)

    Duan, Shun; Yang, Xiaoping; Mei, Fang; Tang, Yan; Li, Xiaoli; Shi, Yuzhou; Mao, Jifu; Zhang, Hongquan; Cai, Qing

    2015-04-01

    Carbon nanomaterials (CNMs), such as carbon nanotube (CNT) and graphene, are highlighted in bone regeneration because of their osteoinductive properties. Their combinations with nanofibrous polymeric scaffolds, which mimic the morphology of natural extracellular matrix of bone, arouse keen interest in bone tissue engineering. To this end, CNM were incorporated into nanofibrous poly(L-lactic acid) scaffolds by thermal-induced phase separation. The CNM-containing composite nanofibrous scaffolds were biologically evaluated by both in vitro co-culture of bone mesenchymal stem cells (BMSCs) and in vivo implantation. The nanofibrous structure itself demonstrated significant enhancement in cell adhesion, proliferation and oseogenic differentiation of BMSCs, and with the incorporation of CNM, the composite nanofibrous scaffolds further promoted osteogenic differentiation of BMSCs significantly. Between the two CNMs, graphene showed stronger effect in promoting osteogenic differentiation of BMSCs than CNT. The results of in vivo experiments revealed that the composite nanofibrous scaffolds had both good biocompatibility and strong ability in inducing osteogenesis. CNMs could remarkably enhance the expression of osteogenesis-related proteins as well as the formation of type I collagen. Similarly, the graphene-containing composite nanofibrous scaffolds demonstrated the strongest effect on inducing osteogenesis in vivo. These findings demonstrated that CNM-containing composite nanofibrous scaffolds were obviously more efficient in promoting osteogenesis than pure polymeric scaffolds.

  12. Direct Deposition of Micron-Thick Aligned Ceramic TiO2 Nanofibrous Film on FTOs by Double-Needle Electrospinning Using Air-Turbulence Shielded Disc Collector

    Directory of Open Access Journals (Sweden)

    T. Krishnamoorthy

    2011-01-01

    Full Text Available One-dimensional (1D metal oxides, typically nanowires and nanorods, have unique electronic and optical properties due to quantum phenomena that find applications in modern energy and electronic devices. We present here the electrospinning method that produces the aligned TiO2 nanofibres directly on the fluorine-doped tin oxide (FTO substrates mounted rotating disc collector. The aligned TiO2 ceramic nanofibres mat of 6 μm thickness is achieved in 4 h using a nonconductive enclosed-air-shield with air-hood design over the FTO mounted rotating disc collector. The aligned TiO2 nanofibers are found to retain its integrity and binding on FTO surface even after sintering at 500°C. SIMON 8 modeling package is used to determine the behaviour of the charged polymer/TiO2 jet when single and double needles are used for electrospinning process. The simulation study reveals that the repulsive force of the charged fibers from the double needle exerts stronger electric field distribution along the flow of stream that results in the reduction of the fibers diameter, which is about 28 nm than that of using single-needle system.

  13. Lab-on-a-brane: nanofibrous polymer membranes to recreate organ-capillary interfaces

    Science.gov (United States)

    Budhwani, Karim I.; Thomas, Vinoy; Sethu, Palaniappan

    2016-03-01

    Drug discovery is a complex and time consuming process involving significant basic research and preclinical evaluation prior to testing in patients. Preclinical studies rely extensively on animal models which often fail in human trials. Biomimetic microphysiological systems (MPS) using human cells can be a promising alternative to animal models; where critical interactions between different organ systems are recreated to provide physiologically relevant in vitro human models. Central here are blood-vessel networks, the interface controlling transport of cellular and biomolecular components between the circulating fluid and underlying tissue. Here we present a novel lab-on-a-brane (or lab-on-a-membrane) nanofluidics MPS that combines the elegance of lab-on-a-chip with the more realistic morphology of 3D fibrous tissue-engineering constructs. Our blood-vessel lab-on-a-brane effectively simulates in vivo vessel-tissue interface for evaluating transendothelial transport in various pharmacokinetic and nanomedicine applications. Attributes of our platform include (a) nanoporous barrier interface enabling transmembrane molecular transport, (b) transformation of substrate into nanofibrous 3D tissue matrix, (c) invertible-sandwich architecture, and (d) simple co-culture mechanism for endothelial and smooth muscle layers to accurately mimic arterial anatomy. Structural, mechanical, and transport characterization using scanning electron microscopy, stress/strain analysis, infrared spectroscopy, immunofluorescence, and FITC-Dextran hydraulic permeability confirm viability of this in vitro system. Thus, our lab-on-a-brane provides an effective and efficient, yet considerably inexpensive, physiologically relevant alternative for pharmacokinetic evaluation; possibly reducing animals used in preclinical testing, costs from false starts, and time-to-market. Furthermore, it can be configured in multiple simultaneous arrays for personalized and precision medicine applications and for

  14. Electrospinning strategies of drug-incorporated nanofibrous mats for wound recovery.

    Science.gov (United States)

    Choi, Ji Suk; Kim, Hye Sung; Yoo, Hyuk Sang

    2015-04-01

    Electrospun nanofibrous mats have recently been employed as drug reservoirs for their unique features, such as high surface-to-volume ratios and easy fabrication process. We describe herein various methods of fabricating drug- and gene-encapsulated nanofibrous meshes, which can be prepared by electrospinning. The electrospinning process of nanofibrous mats is affected by many parameters, including viscosity and ejection speeds of the polymeric solutions and the electrical potential applied to the system. Both single- and dual-nozzle systems are widely employed in the preparation of electrospun nanofibers encapsulating drugs and genes, which are usually incorporated into the electrospun mats either by physical mixing with polymeric solutions before electrospinning or by physical incorporation after electrospinning. Various strategies have been tailored to maintain the bioactivity of proteins for tissue regeneration before and after electrospinning. Nucleic acids, such as DNA and siRNA, are also incorporated into nanofibrous meshes to enhance tissue regeneration by expressing transgenes or silencing domestic genes in specific tissues. Drug- or gene-incorporated nanofibrous meshes can greatly increase tissue regeneration rates and reduce scar formation in normal and diabetic wounds. Hybrid nanofibers, with multiple cell layers or hydrogels, have also been used to improve wound healing efficiency by increasing cell infiltration.

  15. Electrospun PVdF-PVC nanofibrous polymer electrolytes for polymer lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Zhong Zheng [Key Laboratory of Environmentally Friendly Chemistry and Applications of Minister of Education, College of Chemistry, Xiangtan University, Xiangtan 411105 (China); Cao Qi, E-mail: wjcaoqi@163.com [Key Laboratory of Environmentally Friendly Chemistry and Applications of Minister of Education, College of Chemistry, Xiangtan University, Xiangtan 411105 (China); Jing Bo; Wang Xianyou; Li Xiaoyun; Deng Huayang [Key Laboratory of Environmentally Friendly Chemistry and Applications of Minister of Education, College of Chemistry, Xiangtan University, Xiangtan 411105 (China)

    2012-01-25

    Highlights: Black-Right-Pointing-Pointer The nanofibrous polymer electrolytes based on PVdF-PVC (8:2, w/w) prepared by electrospinning have an ionic conductivity of 2.25 Multiplication-Sign 10{sup -3} S cm{sup -1} at 25 Degree-Sign C. Black-Right-Pointing-Pointer The nanofibrous polymer electrolytes presented a good electrochemical stability up to 5.1 V (vs. Li/Li{sup +}). Black-Right-Pointing-Pointer The nanofibrous polymer electrolytes showed a very good charge/discharge and cycling performance. - Abstract: Nanofibrous membranes based on Poly (vinyl difluoride) (PVdF)-Poly (vinyl chloride) (PVC) (8:2, w/w) were prepared by electrospinning and then they were soaked in a liquid electrolyte to form polymer electrolytes (PEs). The morphology, thermal stability, function groups and crystallinity of the electrospun membranes were characterized by scanning electron microscope (SEM), thermal analysis (TG), Fourier transform infrared spectra (FT-IR) and differential scanning calorimetry (DSC), respectively. It was found that both electrolyte uptake and ionic conductivity of the composite PEs increased with the addition of PVC. The composite PVdF-PVC PEs had a high ionic conductivity up to 2.25 Multiplication-Sign 10{sup -3} S cm{sup -1} at 25 Degree-Sign C. These results showed that nanofibrous PEs based on PVdF-PVC were of great potential application in polymer lithium-ion batteries.

  16. Dual-biomimetic superhydrophobic electrospun polystyrene nanofibrous membranes for membrane distillation.

    Science.gov (United States)

    Li, Xiong; Wang, Ce; Yang, Yin; Wang, Xuefen; Zhu, Meifang; Hsiao, Benjamin S

    2014-02-26

    A new type of dual-biomimetic hierarchically rough polystyrene (PS) superhydrophobic micro/nano-fibrous membrane was fabricated via a one-step electrospinning technique at various polymer concentrations from 15 to 30 wt %. The obtained micro/nano-fibers exhibited a nanopapillose, nanoporous, and microgrooved surface morphology that originated from mimicking the micro/nanoscale hierarchical structures of lotus leaf and silver ragwort leaf, respectively. Superhydrophobicity and high porosity of such resultant electrospun nanofibrous membranes make them attractive candidates for membrane distillation (MD) application with low energy water recovery. In this study, two kinds of optimized PS nanofibrous membranes with different thicknesses were applied for desalination via direct contact MD. The membranes maintained a high and stable permeate water vapor flux (104.8 ± 4.9 kg/m(2)·h, 20 g/L NaCl salt feed for a thinner PS nanofibrous membrane with thickness of 60 μm; 51 ± 4.5 kg/m(2)·h, 35 g/L NaCl salt feed for the thicker sample with thickness of 120 μm; ΔT = 50 °C) for a test period of 10 h without remarkable membrane pores wetting detected. These results were better than those of typical commercial polyvinylidene fluoride (PVDF) MD membranes or related PVDF nanofibrous membranes reported in literature, suggesting excellent competency of PS nanofibrous membranes for MD applications.

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

    Science.gov (United States)

    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.

  18. Fabrication and evaluation of poly(epsilon-caprolactone)/silk fibroin blend nanofibrous scaffold.

    Science.gov (United States)

    Lim, Jun Sik; Ki, Chang Seok; Kim, Jong Wook; Lee, Kwang Gil; Kang, Seok Woo; Kweon, Hae Yong; Park, Young Hwan

    2012-05-01

    In this study we investigated the blend electrospinning of poly(ϵ-caprolactone) (PCL) and silk fibroin (SF) to improve the biodegradability and biocompatibility of PCL-based nanofibrous scaffolds. Optimal conditions to fabricate PCL/SF (50/50) blend nanofiber were established for electrospinning using formic acid as a cosolvent and three-dimensional (3D) PCL/SF blend nanofibrous scaffolds were prepared by a modified electrospinning process using methanol coagulation bath. The physical properties of 2D PCL/SF blend nanofiber mats and 3D highly porous blend nanofibrous scaffolds were measured and compared. To evaluate cytocompatibility of the 3D blend scaffolds as compared to 3D PCL nanofibrous scaffold, normal human dermal fibroblasts were cultured. It is concluded that biodegradability and cytocompatibility could be improved for the 3D highly porous PCL/SF (50/50) blend nanofibrous scaffold prepared by blending PCL with SF in electrospinning. In addition to the blending of PCL and SF, the 3D structure and high porosity of electrospun nanofiber assemblies may also be important factors for enhancing the performance of scaffolds.

  19. Electrocatalytic oxidation behavior of L-cysteine at Pt microparticles modified nanofibrous polyaniline film electrode

    Institute of Scientific and Technical Information of China (English)

    MA Song-jiang; LUO Sheng-lian; ZHOU Hai-hui; KUANG Ya-fei; NING Xiao-hui

    2008-01-01

    Platinum(Pt)/nanofibrous polyaniline(PANI) electrode was prepared by pulse galvanostatic method and characterized by scanning electron microscopy. The electrochemical behavior of L-cysteine at the Pt/nanofibrous PANI electrode was investigated by cyclic voltammetry. The results indicate that the pH value of the solution and the Pt loading of the electrode have great effect on the electrocatalytic property of the Pt/nanofibrous PANI electrode; the suitable Pt loading of the electrode is 600 μg/cm2 and the suitable pH value of the solution is 4.5 for investigating L-cysteine oxidation. The L-cysteine sensor based on the Pt/nanofibrous PANI electrode has a good selectivity, reproducibility and stability. The Pt/nanofibrous PANI electrode is highly sensitive to L-cysteine, and the linear calibration curve for the oxidation of L-cysteine can be observed in the range of 0.2-5.0 mmol/L.

  20. Rhizobia survival in seeds coated with polyvinyl alcohol (PVA) electrospun nanofibres.

    Science.gov (United States)

    Damasceno, Raquel; Roggia, Isabel; Pereira, Claudio; de Sá, Enilson

    2013-11-01

    The electrospinning technique of rhizobia immobilization in nanofibres is an innovative and promising alternative for reducing the harmful effects of environmental stress on bacteria strains in a possible inoculant nanotechnology product for use in agriculture. The use of polyvinyl alcohol (PVA) shows up as an effective polymer in cell encapsulation because of its physical characteristics, such as viscosity and power of scattering. The aim of these studies has been to evaluate the survival of rhizobia incorporated in PVA nanofibres, which were applied to soybean seed and then subjected to different storage times and exposure to fungicide. The maintenance of the symbiotic characteristics of the incorporated bacterial strains was also evaluated, noting the formation of nodules in the soybean seedlings. No significant differences in the cell survival at 0 h and after 24 h of storage were observed. After 48 h, a significant difference in the bacterial cell concentration of the seeds affixed with PVA nanofibres was observed. Exposure to the fungicide decreased the viability of the bacteria strains even when coated with the nanofibres. A larger number of nodules formed in soybean seedlings from seeds inoculated with rhizobia incorporated in PVA nanofibres than from seeds inoculated with rhizobia without PVA. Thus, the electrospinning technique is a great alternative to the usual protector inoculants because of its unprecedented capacity to control the release of bacteria.

  1. Protein nanocoatings on synthetic polymeric nanofibrous membranes designed as carriers for skin cells

    Science.gov (United States)

    Bacakova, Marketa; Pajorova, Julia; Stranska, Denisa; Hadraba, Daniel; Lopot, Frantisek; Riedel, Tomas; Brynda, Eduard; Zaloudkova, Margit; Bacakova, Lucie

    2017-01-01

    Protein-coated resorbable synthetic polymeric nanofibrous membranes are promising for the fabrication of advanced skin substitutes. We fabricated electrospun polylactic acid and poly(lactide-co-glycolic acid) nanofibrous membranes and coated them with fibrin or collagen I. Fibronectin was attached to a fibrin or collagen nanocoating, in order further to enhance the cell adhesion and spreading. Fibrin regularly formed a coating around individual nanofibers in the membranes, and also formed a thin noncontinuous nanofibrous mesh on top of the membranes. Collagen also coated most of the fibers of the membrane and randomly created a soft gel on the membrane surface. Fibronectin predominantly adsorbed onto a thin fibrin mesh or a collagen gel, and formed a thin nanofibrous structure. Fibrin nanocoating greatly improved the attachment, spreading, and proliferation of human dermal fibroblasts, whereas collagen nanocoating had a positive influence on the behavior of human HaCaT keratinocytes. In addition, fibrin stimulated the fibroblasts to synthesize fibronectin and to deposit it as an extracellular matrix. Fibrin coating also showed a tendency to improve the ultimate tensile strength of the nanofibrous membranes. Fibronectin attached to fibrin or to a collagen coating further enhanced the adhesion, spreading, and proliferation of both cell types. PMID:28223803

  2. Preparation and photocatalytic activity of Gd-doped TiO2 nanofibre

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yi; ZHANG Shi-ying; ZHU Zhi-ping; LI Yong-kun

    2005-01-01

    In order to realize the photocatalysis of TiO2 in the sunlight and directly apply it to waste water treatment, the Gd-doped TiO2 nanofibre was synthesized using two-step synthesis method as follows: Firstly, potassium carbonate, titanium dioxide and proper gadolinium oxide (dopant) were calcined in the muffle at high temperature and the doped gadolinium K2Ti4O9 fibres were obtained; secondly, the fibre was heated using glycerol as solvent until Gd-doped TiO2 nanofibres were obtained. The synthesized samples were characterized using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. The results show that Gd-doped TiO2 nanofibre heat-treated by glycerol solvent can inhibit the agglomeration, so the grain diameter of the fibre is smaller than that without heat-treated with glycerol. Meanwhile, the diameter of the fibre decreases with the increase of the heating temperature and time. 97%- 98% of Gd-doped TiO2 nanofibre is anatase. The photocatalysis results showed that the photocatalysis activity of Gd-doped TiO2 nanofibre is just a little lower than that of TiO2 powder.

  3. Deformation of isolated single-wall carbon nanotubes in electrospun polymer nanofibres

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, Prabhakaran; Eichhorn, Stephen J; Young, Robert J [Materials Science Centre, School of Materials, University of Manchester, Manchester M1 7HS (United Kingdom)

    2007-06-13

    Electrospinning has been used to prepare poly(vinyl alcohol) (PVA) nanofibres, with diameters ranging from 1 {mu}m down to 20 nm, that contain dispersions of isolated, well-aligned, single-wall carbon nanotubes (SWNTs). The nanofibres were characterized by electron microscopy and Raman spectroscopy. Single Raman radial breathing modes (RBMs) were found for the SWNTs in the nanofibres which allowed the identification of particular nanotubes and indicated debundling/separation of the original SWNT ropes. Moreover the results of polarized Raman spectroscopy were consistent with the presence of isolated SWNTs, well-aligned along the nanofibre axes. The nanofibres were subjected to deformation and the position of the G and G{sup '} bands was followed as a function of strain. It was found that large band shifts were obtained, indicating that there was good stress transfer from the PVA matrix to the nanotubes. A band shift of up to 40 cm{sup -1} for 1% strain was found for the G{sup '} band which is similar to that reported for the deformation of isolated nanotubes. This indicates that the Young's modulus of SWNTs is in excess of 800 GPa.

  4. Deformation of isolated single-wall carbon nanotubes in electrospun polymer nanofibres

    Science.gov (United States)

    Kannan, Prabhakaran; Eichhorn, Stephen J.; Young, Robert J.

    2007-06-01

    Electrospinning has been used to prepare poly(vinyl alcohol) (PVA) nanofibres, with diameters ranging from 1 µm down to 20 nm, that contain dispersions of isolated, well-aligned, single-wall carbon nanotubes (SWNTs). The nanofibres were characterized by electron microscopy and Raman spectroscopy. Single Raman radial breathing modes (RBMs) were found for the SWNTs in the nanofibres which allowed the identification of particular nanotubes and indicated debundling/separation of the original SWNT ropes. Moreover the results of polarized Raman spectroscopy were consistent with the presence of isolated SWNTs, well-aligned along the nanofibre axes. The nanofibres were subjected to deformation and the position of the G and G' bands was followed as a function of strain. It was found that large band shifts were obtained, indicating that there was good stress transfer from the PVA matrix to the nanotubes. A band shift of up to 40 cm-1 for 1% strain was found for the G' band which is similar to that reported for the deformation of isolated nanotubes. This indicates that the Young's modulus of SWNTs is in excess of 800 GPa.

  5. ITO/poly(aniline)/sol-gel glass: An optically transparent, pH-responsive substrate for supported lipid bilayers.

    Science.gov (United States)

    Al-Obeidi, Ahmed; Ge, Chenhao; Orosz, Kristina S; Saavedra, S Scott

    2013-01-01

    Described here is fabrication of a pH-sensitive, optically transparent transducer composed of a planar indium-tin oxide (ITO) electrode overcoated with a a poly(aniline) (PANI) thin film and a porous sol-gel layer. Adsorption of the PANI film renders the ITO electrode sensitive to pH, whereas the sol-gel spin-coated layer makes the upper surface compatible with fusion of phospholipid vesicles to form a planar supported lipid bilayer (PSLB). The response to changes in the pH of the buffer contacting the sol-gel/PANI/ITO electrode is pseudo-Nernstian with a slope of 52 mV/pH over a pH range of 4-9. Vesicle fusion forms a laterally continuous PSLB on the upper sol-gel surface that is fluid with a lateral lipid diffusion coefficient of 2.2 μm(2)/s measured by fluorescence recovery after photobleaching. Due to its lateral continuity and lack of defects, the PSLB blocks the pH response of the underlying electrode to changes in the pH of the overlying buffer. This architecture is simpler to fabricate than previously reported ITO electrodes derivatized for PSLB formation, and should be useful for optical monitoring of proton transport across supported membranes derivatized with ionophores and ion channels.

  6. ITO/Poly(Aniline/Sol-Gel Glass: An Optically Transparent, pH-Responsive Substrate for Supported Lipid Bilayers

    Directory of Open Access Journals (Sweden)

    Ahmed Al-Obeidi

    2013-01-01

    Full Text Available Described here is fabrication of a pH-sensitive, optically transparent transducer composed of a planar indium-tin oxide (ITO electrode overcoated with a poly(aniline (PANI thin film and a porous sol-gel layer. Adsorption of the PANI film renders the ITO electrode sensitive to pH, whereas the sol-gel spin-coated layer makes the upper surface compatible with fusion of phospholipid vesicles to form a planar supported lipid bilayer (PSLB. The response to changes in the pH of the buffer contacting the sol-gel/PANI/ITO electrode is pseudo-Nernstian with a slope of 52 mV/pH over a pH range of 4–9. Vesicle fusion forms a laterally continuous PSLB on the upper sol-gel surface that is fluid with a lateral lipid diffusion coefficient of 2.2 μm2/s measured by fluorescence recovery after photobleaching. Due to its lateral continuity and lack of defects, the PSLB blocks the pH response of the underlying electrode to changes in the pH of the overlying buffer. This architecture is simpler to fabricate than previously reported ITO electrodes derivatized for PSLB formation and should be useful for optical monitoring of proton transport across supported membranes derivatized with ionophores and ion channels.

  7. Heparin/collagen encapsulating nerve growth factor multilayers coated aligned PLLA nanofibrous scaffolds for nerve tissue engineering.

    Science.gov (United States)

    Zhang, Kuihua; Huang, Dianwu; Yan, Zhiyong; Wang, Chunyang

    2017-07-01

    Biomimicing topological structure of natural nerve tissue to direct axon growth and controlling sustained release of moderate neurotrophic factors are extremely propitious to the functional recovery of damaged nervous systems. In this study, the heparin/collagen encapsulating nerve growth factor (NGF) multilayers were coated onto the aligned poly-L-lactide (PLLA) nanofibrous scaffolds via a layer-by-layer (LbL) self-assembly technique to combine biomolecular signals, and physical guidance cues for peripheral nerve regeneration. Scanning electronic microscopy (SEM) revealed that the surface of aligned PLLA nanofibrous scaffolds coated with heparin/collagen multilayers became rougher and appeared some net-like filaments and protuberances in comparison with PLLA nanofibrous scaffolds. The heparin/collagen multilayers did not destroy the alignment of nanofibers. X-ray photoelectron spectroscopy and water contact angles displayed that heparin and collagen were successfully coated onto the aligned PLLA nanofibrous scaffolds and improved its hydrophilicity. Three-dimensional (3 D) confocal microscopy images further demonstrated that collagen, heparin, and NGF were not only coated onto the surface of aligned PLLA nanofibrous scaffolds but also permeated into the inner of scaffolds. Moreover, NGF presented a sustained release for 2 weeks from aligned nanofibrous scaffolds coated with 5.5 bilayers or above and remained good bioactivity. The heparin/collagen encapsulating NGF multilayers coated aligned nanofibrous scaffolds, in particular 5.5 bilayers or above, was more beneficial to Schwann cells (SCs) proliferation and PC12 cells differentiation as well as the SC cytoskeleton and neurite growth along the direction of nanofibrous alignment compared to the aligned PLLA nanofibrous scaffolds. This novel scaffolds combining sustained release of bioactive NGF and aligned nanofibrous topography presented an excellent potential in peripheral nerve regeneration. © 2016 Wiley

  8. Structurally stabilized mesoporous TiO2 nanofibres for efficient dye-sensitized solar cells

    Directory of Open Access Journals (Sweden)

    Fargol Hasani Bijarbooneh

    2013-09-01

    Full Text Available One-dimensional (1D TiO2 nanostructures are very desirable for providing fascinating properties and features, such as high electron mobility, quantum confinement effects, and high specific surface area. Herein, 1D mesoporous TiO2 nanofibres were prepared using the electrospinning method to verify their potential for use as the photoelectrode of dye-sensitized solar cells (DSSCs. The 1D mesoporous nanofibres, 300 nm in diameter and 10-20 μm in length, were aggregated from anatase nanoparticles 20-30 nm in size. The employment of these novel 1D mesoporous nanofibres significantly improved dye loading and light scattering of the DSSC photoanode, and resulted in conversion cell efficiency of 8.14%, corresponding to an ∼35% enhancement over the Degussa P25 reference photoanode.

  9. Superhydrophobic PVDF and PVDF-HFP nanofibrous mats with antibacterial and anti-biofouling properties

    Science.gov (United States)

    Spasova, M.; Manolova, N.; Markova, N.; Rashkov, I.

    2016-02-01

    Superhydrophobic nanofibrous materials of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) were prepared by one-pot electrospinning technique. The mats were decorated with ZnO nanoparticles with silanized surface and a model drug - 5-chloro-8-hydroxyquinolinol (5Cl8HQ). The obtained hybrid nanofibrous materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle measurements, mechanical and microbiological tests. The results showed that the incorporation of ZnO nanoparticles into PVDF and PVDF-HFP nanofibers increased the hydrophobicity (contact angle 152°), improved the thermal stability and imparted to the nanofibrous materials anti-adhesive and antimicrobial properties. The mats containing the model drug possessed antibacterial activity against Escherichia coli and Staphylococcus aureus. The results suggested that the obtained hybrid mats could find potential biomedical applications requiring antibacterial and anti-biofouling properties.

  10. Super-resolution microscopy reveals structural diversity in molecular exchange among peptide amphiphile nanofibres

    Science.gov (United States)

    da Silva, Ricardo M. P.; van der Zwaag, Daan; Albertazzi, Lorenzo; Lee, Sungsoo S.; Meijer, E. W.; Stupp, Samuel I.

    2016-05-01

    The dynamic behaviour of supramolecular systems is an important dimension of their potential functions. Here, we report on the use of stochastic optical reconstruction microscopy to study the molecular exchange of peptide amphiphile nanofibres, supramolecular systems known to have important biomedical functions. Solutions of nanofibres labelled with different dyes (Cy3 and Cy5) were mixed, and the distribution of dyes inserting into initially single-colour nanofibres was quantified using correlative image analysis. Our observations are consistent with an exchange mechanism involving monomers or small clusters of molecules inserting randomly into a fibre. Different exchange rates are observed within the same fibre, suggesting that local cohesive structures exist on the basis of β-sheet discontinuous domains. The results reported here show that peptide amphiphile supramolecular systems can be dynamic and that their intermolecular interactions affect exchange patterns. This information can be used to generate useful aggregate morphologies for improved biomedical function.

  11. Single-step fabrication of microfluidic channels filled with nanofibrous membrane using femtosecond laser irradiation

    Science.gov (United States)

    Tavangar, Amirhossein; Tan, Bo; Venkatakrishnan, K.

    2010-08-01

    In this paper, we demonstrate a new method of fabricating silicon microfluidic channels filled with a porous nanofibrous structure utilizing a femtosecond laser. The nanofibrous structure can act as a membrane used for microfiltration. This method allows us to generate both the microfluidic channel and the fibrous nanostructure in a single step under ambient conditions. Due to laser irradiation, a large number of nanoparticles ablate from the channel surface, and then aggregate and grow into porous nanofibrous structures and fill the channels. Energy dispersive x-ray spectroscopy (EDS) analysis was conducted to examine the oxygen concentration in the membrane structure. Our results demonstrated that by controlling the laser parameters including pulse repetition, pulse width and scanning speed, different microfluidic channels with a variety of porosity could be obtained.

  12. A simple approach to constructing antibacterial and anti-biofouling nanofibrous membranes.

    Science.gov (United States)

    Mei, Yan; Yao, Chen; Li, Xinsong

    2014-01-01

    In this work, antibacterial and anti-adhesive polymeric thin films were constructed on polyacrylonitrile (PAN) nanofibrous membranes in order to extend their applications. Polyhexamethylene guanidine hydrochloride (PHGH) as an antibacterial agent and heparin (HP) as an anti-adhesive agent have been successfully coated onto the membranes via a layer-by-layer (LBL) assembly technique confirmed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), energy-dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). The antibacterial properties of LBL-functionalized PAN nanofibrous membranes were evaluated using the Gram-positive bacterium Staphylococcus aureus and the Gram-negative Escherichia coli. Furthermore, the dependence of the antibacterial activity and anti-biofouling performance on the number of layers in the LBL films was investigated quantitatively. It was found that these LBL-modified nanofibrous membranes possessed high antibacterial activities, easy-cleaning properties and stability under physiological conditions, thus qualifying them as candidates for anti-biofouling coatings.

  13. Study of polyvinyl alcohol nanofibrous membrane by electrospinning as a magnetic nanoparticle delivery approach

    Energy Technology Data Exchange (ETDEWEB)

    Ger, Tzong-Rong; Huang, Hao-Ting; Hu, Keng-Shiang [Institute of NanoEngineering and MicroSystems, National Tsing Hua University, Hsinchu, Taiwan (China); Huang, Chen-Yu [Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu, Taiwan (China); Lai, Jun-Yang [Department of Applied Physics, National Ping Tung University of Education, Pingtung, Taiwan (China); Chen, Jiann-Yeu [Center of Nanoscience and Nanotechnology, National Chung Hsing University, Taichung, Taiwan (China); Lai, Mei-Feng, E-mail: mflai@mx.nthu.edu.tw [Institute of NanoEngineering and MicroSystems, National Tsing Hua University, Hsinchu, Taiwan (China); Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu, Taiwan (China)

    2014-05-07

    Electrospinning technique was used to fabricate polyvinyl alcohol (PVA)-based magnetic biodegradable nanofibers. PVA solution was mixed with ferrofluid or magnetic nanoparticles (MNPs) powder and formed two individual nanofibrous membranes (PVA/ferrofluid and PVA/MNPs powder) by electrospinning. The surface morphology of the nanofibrous membrane was characterized by scanning electron microscopy and the magnetic properties were measured by vibrating sample magnetometer. Macrophages (RAW 264.7) were co-cultured with the nanofibrous membranes for 12, 24, and 48 h and exhibited good cell viability (>95%). Results showed that the PVA fibers would be degraded and the embedded Fe{sub 3}O{sub 4} nanoparticles would be released and delivered to cells.

  14. Process of making titanium carbide (TiC) nano-fibrous felts

    Energy Technology Data Exchange (ETDEWEB)

    Fong, Hao; Zhang, Lifeng; Zhao, Yong; Zhu, Zhengtao

    2015-01-13

    A method of synthesizing mechanically resilient titanium carbide (TiC) nanofibrous felts comprising continuous nanofibers or nano-ribbons with TiC crystallites embedded in carbon matrix, comprising: (a) electrospinning a spin dope for making precursor nanofibers with diameters less than 0.5 J.Lm; (b) overlaying the nanofibers to produce a nanofibrous mat (felt); and then (c) heating the nano-felts first at a low temperature, and then at a high temperature for making electrospun continuous nanofibers or nano-ribbons with TiC crystallites embedded in carbon matrix; and (d) chlorinating the above electrospun nano-felts at an elevated temperature to remove titanium for producing carbide derived carbon (CDC) nano-fibrous felt with high specific surface areas.

  15. Sub-Doppler temperature measurements of laser-cooled atoms using optical nanofibres

    Science.gov (United States)

    Russell, Laura; Deasy, Kieran; Daly, Mark J.; Morrissey, Michael J.; Chormaic, Síle Nic

    2012-01-01

    We present a method for measuring the average temperature of a cloud of cold 85Rb atoms in a magneto-optical trap using an optical nanofibre. A periodic spatial variation is applied to the magnetic fields generated by the trapping coils and this causes the trap centre to oscillate, which, in turn, causes the cloud of cold atoms to oscillate. The optical nanofibre is used to collect the fluorescence emitted by the cold atoms, and the frequency response between the motion of the centre of the oscillating trap and the cloud of atoms is determined. This allows us to make measurements of cloud temperature both above and below the Doppler limit, thereby paving the way for nanofibres to be integrated with ultracold atoms for hybrid quantum devices.

  16. A green synthetic strategy of nickel hexacyanoferrate nanoparticals supported on the graphene substrate and its non-enzymatic amperometric sensing application

    Science.gov (United States)

    xue, Zhonghua; He, Nan; Rao, Honghong; Hu, Chenxian; Wang, Xiaofen; Wang, Hui; Liu, Xiuhui; Lu, Xiaoquan

    2017-02-01

    Rapid glucose detection is a key requirement for both diagnosis and treatment of diabetes. A facile and green strategy to achieve spherical-shaped nickel hexacyanoferrate (NiHCF) nanoparticals supported on electrochemical reduction graphene oxide by using electrochemical cyclic voltammetry is explored. As a sensing substrate, electrochemical reduction graphene oxide deposited on a glassy carbon electrode surface exhibited obvious positive effect on the electrodeposition of NiHCF nanoparticals with spherical structure and thus effectively improved the electrical conductivity and electrochemical sensing of the proposed amperometric sensor. Proof-concept experiments demonstrated that the proposed nanocomposites modified electrode exhibited excellent sensitivity toward glucose oxidation as well as with a satisfying detection limit of 0.11 μM. More importantly, we also explore that as a simple, green and facile method, electrochemical technology can be employed and provide a new strategy for developing GO and metal hexacyanoferrate based amperometric sensing platform toward glucose and other biomolecules.

  17. Synthesis of nano-carbon (nanotubes, nanofibres, graphene) materials

    Indian Academy of Sciences (India)

    Kalpana Awasthi; Rajesh Kumar; Himanshu Raghubanshi; Seema Awasthi; Ratnesh Pandey; Devinder Singh; T P Yadav; O N Srivastava

    2011-07-01

    In the present study, we report the synthesis of carbon nanotubes (CNTs) using a new natural precursor: castor oil. The CNTs were synthesized by spray pyrolysis of castor oil–ferrocene solution at 850°C under an Ar atmosphere. We also report the synthesis of carbon nitrogen (C–N) nanotubes using castor oil–ferrocene–ammonia precursor. The as-grown CNTs and C–N nanotubes were characterized through scanning and transmission electron microscopic techniques. Graphitic nanofibres (GNFs) were synthesized by thermal decomposition of acetylene (C2H2) gas using Ni catalyst at 600°C. As-grown GNFs reveal both planar and helical morphology. We have investigated the structural and electrical properties of multi-walled CNTs (MWNTs)–polymer (polyacrylamide (PAM)) composites. The MWNTs–PAM composites were prepared using as purified, with ball milling and functionalized MWNTs by solution cast technique and characterized through SEM. A comparative study has been made on the electrical property of these MWNTs–PAM composites with different MWNTs loadings. It is shown that the ball milling and functionalization of MWNTs improves the dispersion of MWNTs into the polymer matrix. Enhanced electrical conductivity was observed for the MWNTs–PAM composites. Graphene samples were prepared by thermal exfoliation of graphite oxide. XRD analysis confirms the formation of graphene.

  18. Naturally derived biofunctional nanofibrous scaffold for skin tissue regeneration.

    Science.gov (United States)

    Suganya, S; Venugopal, J; Ramakrishna, S; Lakshmi, B S; Dev, V R Giri

    2014-07-01

    Significant wound healing activity of Aloe vera (AV) and higher elastic strength of Silk fibroin (SF) along with mammalian cell compatibility makes AV and SF an attractive material for tissue engineering. The purpose of the present work was to combine their unique properties, with the advantage of electrospinning to prepare a hybrid transdermal biomaterial for dermal substitutes. The physico-chemical characterization of the developed scaffold showed finer morphology expressing amino and esteric groups with improved hydrophilic properties and favorable tensile strain of 116% desirable for skin tissue engineering. Their biological response showed favorable fibroblast proliferation compared to control which almost increased linearly by (p<0.01) 34.68% on day 3, (p<0.01) 19.13% on day 6, and (p<0.001) 97.86% on day 9 with higher expression of CMFDA, collagen and F-actin proteins. The obtained results prove that the nanofibrous scaffold with synergistic property of AV and SF would be a potential biomaterial for skin tissue regeneration.

  19. Tailoring material properties of a nanofibrous extracellular matrix derived hydrogel

    Science.gov (United States)

    Johnson, Todd D.; Lin, Stephen Y.; Christman, Karen L.

    2011-12-01

    In the native tissue, the interaction between cells and the extracellular matrix (ECM) is essential for cell migration, proliferation, differentiation, mechanical stability, and signaling. It has been shown that decellularized ECMs can be processed into injectable formulations, thereby allowing for minimally invasive delivery. Upon injection and increase in temperature, these materials self-assemble into porous gels forming a complex network of fibers with nanoscale structure. In this study we aimed to examine and tailor the material properties of a self-assembling ECM hydrogel derived from porcine myocardial tissue, which was developed as a tissue specific injectable scaffold for cardiac tissue engineering. The impact of gelation parameters on ECM hydrogels has not previously been explored. We examined how modulating pH, temperature, ionic strength, and concentration affected the nanoscale architecture, mechanical properties, and gelation kinetics. These material characteristics were assessed using scanning electron microscopy, rheometry, and spectrophotometry, respectively. Since the main component of the myocardial matrix is collagen, many similarities between the ECM hydrogel and collagen gels were observed in terms of the nanofibrous structure and modulation of properties by altering ionic strength. However, variation from collagen gels was noted for the gelation temperature along with varied times and rates of gelation. These discrepancies when compared to collagen are likely due to the presence of other ECM components in the decellularized ECM based hydrogel. These results demonstrate how the material properties of ECM hydrogels could be tailored for future in vitro and in vivo applications.

  20. Nanofibrous polymeric beads from aramid fibers for efficient bilirubin removal.

    Science.gov (United States)

    Peng, Zihang; Yang, Ye; Luo, Jiyue; Nie, Chuanxiong; Ma, Lang; Cheng, Chong; Zhao, Changsheng

    2016-08-16

    Polymer based hemoperfusion has been developed as an effective therapy to remove the extra bilirubin from patients. However, the currently applied materials suffer from either low removal efficiency or poor blood compatibility. In this study, we report the development of a new class of nanofibrous absorbent that exhibited high bilirubin removal efficiency and good blood compatibility. The Kevlar nanofiber was prepared by dissolving micron-sized Kevlar fiber in proper solvent, and the beads were prepared by dropping Kevlar nanofiber solutions into ethanol. Owing to the nanofiborous structure of the Kevlar nanofiber, the beads displayed porous structures and large specific areas, which would facilitate the adsorption of toxins. In the adsorption test, it was noticed that the beads possessed an adsorption capacity higher than 40 mg g(-1) towards bilirubin. In plasma mimetic solutions, the beads still showed high bilirubin removal efficiency. Furthermore, after incorporating with carbon nanotubes, the beads were found to have increased adsorption capacity for human degradation waste. Moreover, the beads showed excellent blood compatibility in terms of a low hemolysis ratio, prolonged clotting times, suppressed coagulant activation, limited platelet activation, and inhibited blood related inflammatory activation. Additionally, the beads showed good compatibility with endothelial cells. In general, the Kevlar nanofiber beads, which integrated with high adsorption capacity, good blood compatibility and low cytotoxicity, may have great potential for hemoperfusion and some other applications in biomedical fields.

  1. Advancements in electrospinning of polymeric nanofibrous scaffolds for tissue engineering.

    Science.gov (United States)

    Ingavle, Ganesh C; Leach, J Kent

    2014-08-01

    Polymeric nanofibers have potential as tissue engineering scaffolds, as they mimic the nanoscale properties and structural characteristics of native extracellular matrix (ECM). Nanofibers composed of natural and synthetic polymers, biomimetic composites, ceramics, and metals have been fabricated by electrospinning for various tissue engineering applications. The inherent advantages of electrospinning nanofibers include the generation of substrata with high surface area-to-volume ratios, the capacity to precisely control material and mechanical properties, and a tendency for cellular in-growth due to interconnectivity within the pores. Furthermore, the electrospinning process affords the opportunity to engineer scaffolds with micro- to nanoscale topography similar to the natural ECM. This review describes the fundamental aspects of the electrospinning process when applied to spinnable natural and synthetic polymers; particularly, those parameters that influence fiber geometry, morphology, mesh porosity, and scaffold mechanical properties. We describe cellular responses to fiber morphology achieved by varying processing parameters and highlight successful applications of electrospun nanofibrous scaffolds when used to tissue engineer bone, skin, and vascular grafts.

  2. Bicomponent AgCl/PVP nanofibre fabricated by electrospinning with gel–sol method

    Indian Academy of Sciences (India)

    Jie Bai; Yaoxian Li; Lei Sun; Chaoqun Zhang; Qingbiao Yang

    2009-04-01

    A new series of poly(vinyl pyrrolidone) (PVP) and silver chloride nanoparticles (AgCl) composite fibres have been synthesized by electrospinning and gel–sol technology. We used sol–gel process to prepare AgCl nanoparticles in the PVP solution, and then the solutions were electrospun to obtain AgCl/PVP composite nanofibres. The final products were thoroughly characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and field-emission scanning electron microscopy (FESEM), which showed the formation of AgCl nanoparticles/PVP composite nanofibres.

  3. Gliding arc surface modification of carrot nanofibre coating - perspective for composite processing

    DEFF Research Database (Denmark)

    Kusano, Yukihiro; Berglund, L; Aitomäki, Y

    2016-01-01

    Surfaces of carrot nanofibre coatings were modified by a gliding arc in atmospheric pressure air. The treatment strengthened wetting of deionized water and glycerol, increased an oxygen content, C-O and C=O, and moderately roughened the surfaces. In the perspective of composite materials, these c......Surfaces of carrot nanofibre coatings were modified by a gliding arc in atmospheric pressure air. The treatment strengthened wetting of deionized water and glycerol, increased an oxygen content, C-O and C=O, and moderately roughened the surfaces. In the perspective of composite materials...

  4. Secondary nanotube growth on aligned carbon nanofibre arrays for superior field emission.

    Science.gov (United States)

    Watts, Paul C P; Lyth, Stephen M; Henley, Simon J; Silva, S Ravi P

    2008-04-01

    We report substantial improvement of the field emission properties from aligned carbon nanotubes grown on aligned carbon nanofibres by a two-stage plasma enhanced chemical vapour deposition (PECVD) process. The threshold field decreased from 15.0 to 3.6 V/microm after the secondary growth. The field enhancement factor increased from 240 to 1480. This technique allows for superior emission of electrons for carbon nanotube/nanofibre arrays grown directly on highly doped silicon for direct integration in large area displays.

  5. Polymers and formulation strategies of nanofibrous systems for drug delivery application and tissue engineering.

    Science.gov (United States)

    Sebe, I; Kállai-Szabó, B; Zelkó, R; Szabó, D

    2015-01-01

    During the last decade, the formulation of nanofibrous materials loaded with different drugs for biomedical applications has evoked considerable interest. The large specific surface area, the special micro- and macrostructure of fiber mats, the possibility for gradual release and site-specific local delivery of the active compounds lead to cytotoxicity decrease and enhancement of the therapeutic effect of drugs and implants. The present review details the different spinning techniques applied for the design of micro- and nanofibrous drug delivery systems. It furthermore deals with the use of various polymers that are capable for the formation of fiber scaffolds of various biomedical applications.

  6. Electrospun polyvinyl alcohol-polyvinyl pyrrolidone nanofibrous membranes for interactive wound dressing application.

    Science.gov (United States)

    Shankhwar, Nisha; Kumar, Manishekhar; Mandal, Biman B; Robi, P S; Srinivasan, A

    2016-01-01

    Cross-linked polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) composite nanofibrous membranes have been prepared by electrospinning. Mechanical properties of the membranes improved significantly with PVP addition. PVP improved hydrophilicity and sustainable degradation of the membranes. Biocompatibility of the membranes was assessed by in vitro culture of native skin cells (L929 fibroblast and HaCaT keratinocytes). Tests showed sustained release of the antibiotic ciprofloxacin hydrochloride monohydrate by the membranes. Further, zone of inhibition study against Staphylococcus aureus growth demonstrated protective action against external pathogenic microbes. These studies show these simple PVA-PVP nanofibrous membranes are promising interactive antibiotic-eluting wound dressing materials.

  7. Preparation of polypyrrole-embedded electrospun poly(lactic acid) nanofibrous scaffolds for nerve tissue engineering.

    Science.gov (United States)

    Zhou, Jun-Feng; Wang, Yi-Guo; Cheng, Liang; Wu, Zhao; Sun, Xiao-Dan; Peng, Jiang

    2016-10-01

    Polypyrrole (PPy) is a biocompatible polymer with good conductivity. Studies combining PPy with electrospinning have been reported; however, the associated decrease in PPy conductivity has not yet been resolved. We embedded PPy into poly(lactic acid) (PLA) nanofibers via electrospinning and fabricated a PLA/PPy nanofibrous scaffold containing 15% PPy with sustained conductivity and aligned topography. There was good biocompatibility between the scaffold and human umbilical cord mesenchymal stem cells as well as Schwann cells. Additionally, the direction of cell elongation on the scaffold was parallel to the direction of fibers. Our findings suggest that the aligned PLA/PPy nanofibrous scaffold is a promising biomaterial for peripheral nerve regeneration.

  8. Adsorption and photocatalytic degradation of methylene blue over hydrogen-titanate nanofibres produced by a peroxide method.

    Science.gov (United States)

    El Saliby, Ibrahim; Erdei, Laszlo; Kim, Jong-Ho; Shon, Ho Kyong

    2013-08-01

    In this study, Degussa P25 TiO2 was partially dissolved in a mixture of hydrogen peroxide and sodium hydroxide at high pH. The fabrication of nanofibres proceeded by the hydrothermal treatment of the solution at 80 °C. This was followed by acid wash in HCl at pH 2 for 60 min, which resulted in the formation of hydrogen-titanate nanofibres. The nanofibres were annealed at 550 °C for 6 h to produce crystalline anatase nanofibres. The nanofibres were characterised for physico-chemical modifications and tested for the adsorption and photocatalytic degradation of methylene blue as a model water pollutant. An average specific surface area of 31.54 m(2)/g, average pore volume of 0.10 cm(3)/g and average pore size of 50 Å were recorded. The nanofibres were effective adsorbents of the model pollutant and adsorbents and good photocatalysts under simulated solar light illumination. No reduction in photocatalytic activity was observed over three complete treatment cycles, and the effective separation of nanofibres was achieved by gravity settling resulting in low residual solution turbidity.

  9. Fabrication and magnetic properties of Ni_(0.5)Zn_(0.5)Fe_2O_4 nanofibres by electrospinning

    Institute of Scientific and Technical Information of China (English)

    Xiang Jun; Shen Xiang-Qian; Song Fu-Zhan; Liu Ming-Quan

    2009-01-01

    NiZn ferrite/polyvinylpyrrolidone composite fibres were prepared by sol-gel assisted electrospinning. Ni_(0.5)Zn_(0.5)Fe_2O_4 nanofibres with a pure cubic spinel structure were obtained subsequently by calcination of the composite fibres at high temperatures. This paper investigates the thermal decomposition process, structures and morphologies of the electrospun composite fibres and the calcined Ni_(0.5)Zn_(0.5)Fe_2O_4 nanofibres at different temperatures by thermogravimetric and differential thermal analysis, x-ray diffraction, Fourier transform infrared spectroscopy and field emission scanning electron microscopy. The magnetic behaviour of the resultant nanofibres was studied by a vibrating sample magnetometer, It is found that the grain sizes of the nanofibres increase significantly and the nanofibre morphology gradually transforms from a porous structure to a necklace-like nanostructure with the increase of calcination temperature. The Ni_(0.5)Zn_(0.5)Fe_2O_4 nanofibres obtained at 1000℃ for 2 h are characterized by a necklace-like morphology and diameters of 100-200 nm. The saturation magnetization of the random Ni_(0.5)Zn_(0.5)Fe_2O_4 nanofibres increases from 46.5 to 90.2 emu/g when the calcination temperature increases from 450 to 1000℃. The coercivity reaches a maximum value of 11.0 kA/m at a calcination temperature of 600℃. Due to the shape anisotropy, the aligned Ni_(0.5)Zn_(0.5)Fe_2O_4 nanofibres exhibit an obvious magnetic anisotropy and the ease magnetizing direction is parallel to the nanofibre axis.

  10. Poly(aniline) nanowires in sol-gel coated ITO: a pH-responsive substrate for planar supported lipid bilayers.

    Science.gov (United States)

    Ge, Chenhao; Orosz, Kristina S; Armstrong, Neal R; Saavedra, S Scott

    2011-07-01

    Facilitated ion transport across an artificial lipid bilayer coupled to a solid substrate is a function common to several types of bioelectronic devices based on supported membranes, including biomimetic fuel cells and ion channel biosensors. Described here is fabrication of a pH-sensitive transducer composed of a porous sol-gel layer derivatized with poly(aniline) (PANI) nanowires grown from an underlying planar indium-tin oxide (ITO) electrode. The upper sol-gel surface is hydrophilic, smooth, and compatible with deposition of a planar supported lipid bilayer (PSLB) formed via vesicle fusion. Conducting tip AFM was used to show that the PANI wires are connected to the ITO, which convert this electrode into a potentiometric pH sensor. The response to changes in the pH of the buffer contacting the PANI nanowire/sol-gel/ITO electrode is blocked by the very low ion permeability of the overlying fluid PSLB. The feasibility of using this assembly to monitor facilitated proton transport across the PSLB was demonstrated by doping the membrane with lipophilic ionophores that respond to a transmembrane pH gradient, which produced an apparent proton permeability several orders of magnitude greater than values measured for undoped lipid bilayers.

  11. Fabrication and characterization of nano-fibrous bilayer composite for skin regeneration application.

    Science.gov (United States)

    Arasteh, Shaghayegh; Kazemnejad, Somaieh; Khanjani, Sayeh; Heidari-Vala, Hamed; Akhondi, Mohammad Mehdi; Mobini, Sahba

    2016-04-15

    Full thickness wound healing with minimal scarring and complete restoration of normal skin properties still remains as a clinical challenge. In this study, a bilayer skin substitute has been fabricated to biomimic the microstructure of natural extracellular matrix of the skin. Human amniotic membrane (HAM) and silk fibroin nano-fibers were combined to produce bilayer construct, which was further treated and characterized. HAM was obtained from healthy mothers and de-epithelized by means of fine enzymatic method to preserve the extracellular structure. Fibroin protein was extracted from fresh Bombyx mori cocoons and transformed to uniform nano-fiberous structure, which was used as a coating layer on the de-epithelized membrane. Surface modification through oxygen plasma treatment was attempted to further induce hydrophilicity. Subsequently, scaffolds were fully characterized in terms of morphology, mechanical properties, hydrophilicity and cell culture response. Histological and immunohistological staining demonstrated localization of fibronectin, cell denudation and structural integrity of HAM after de-epithelization. Scanning electron microscopy images showed bead-free silk fibroin nano-fibers with the average diameter of 250nm. Water contact angle of bilayer scaffolds reduced dramatically to 26.34° after oxygen plasma treatment, which is correlated with more hydrophilic surface. Due to fibroin nano-fiber coating, mechanical properties of HAM improved significantly. Tensile Young's modulus and tensile strength increased from 16.14MPa and 68.46MPa to 25.69MPa and 108.03MPa, respectively. 14days in vitro cultivation of mouse embryonic fibroblasts on the scaffolds revealed that bilayer scaffolds are able to support cell attachment and proliferation. Plasma-etched scaffolds provided the best niche for cell-matrix crosstalk by allowing cells to penetrate beneath the pores and to integrate in fibers direction. The obtained results suggest that the presented nano-fibrous

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

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Hui [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620 (China); College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Huang, Yunpeng; Shen, Mingwu; Guo, Rui; Cao, Xueyan [College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); Shi, Xiangyang, E-mail: xshi@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai 201620 (China); College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai 201620 (China); CQM - Centro de Quimica da Madeira, Universidade da Madeira, Campus da Penteada, 9000-390 Funchal (Portugal)

    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.

  13. Electrospun nanofibrous materials: a versatile medium for effective oil/water separation

    Directory of Open Access Journals (Sweden)

    Xianfeng Wang

    2016-09-01

    Full Text Available The separation of oil and water is a worldwide challenge due to the ever-increasing amount of oily industrial wastewater and polluted oceanic waters, as well as the increasing frequency of oil spill accidents. As the leader of advanced fibrous materials, electrospun nanofibers combine the properties of tunable wettability, large surface area, high porosity, good connectivity, fine flexibility, and ease of scalable synthesis from various materials (polymer, ceramic, carbon, etc., and they hold great potential for many emerging environmental applications, including the separation of oily wastewater. In this review, the recent progress in the design and fabrication of electrospun nanofibrous materials with tunable surface wettability for oil/water separation applications is summarized and highlighted. This review covers the research and development starting from the design concepts and the synthesis of nanofibrous sorbents, nanofibrous membranes, and nanofibrous aerogels for effective oil/water separation. The review concludes with a brief forecast of challenges and future directions in this rapidly expanding field.

  14. Physicomechanical properties of nanocomposites based on cellulose nanofibre and natural rubber latex

    CSIR Research Space (South Africa)

    Abraham, E

    2012-11-01

    Full Text Available , South Africa 4 School of Chemical Sciences, Mahatma Gandhi University, Kottayam, 686 560, Kerala, India Abstract Cellulose nanofibres (CNF) with diameter 10–60 nm were isolated from raw banana fibres by steam explosion process. These CNF were...

  15. Graphitic nanofibres as catalyst for improving the dehydrogenation behavior of complex aluminium hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, M. Sterlin Leo; Raghubanshi, Himanshu; Pukazhselvan, D.; Srivastava, O.N. [Banaras Hindu Univ., Varnasi (India). Hydrogen Energy Center

    2010-07-01

    In the present work, we explored the catalytic effect of graphitic nanofibres (GNF) particularly of two different morphology, namely planar graphitic nanofibre (PGNF) and helical graphitic nanofibre (HGNF) for enhancement of hydrogen desorption from complex aluminium hydrides such as LiAlH{sub 4} and LiMg(AlH{sub 4}){sub 3}. We found that the catalytic activity of fibres depends mainly on its morphology. Hence helical morphology fibres possess superior catalytic activity than planar graphitic nanofibres. The desorption temperature for 8 mol% HGNF admixed LiAlH{sub 4} gets lowered from 159 C to 128 C with significantly faster kinetics. In 8 mol% HGNF admixed LiMg(AlH{sub 4}){sub 3} sample, the desorption temperature gets lowered from 105 C to {proportional_to}70 C. The activation energy calculated for the first step decomposition of LiAlH{sub 4} admixed with 8 mol% HGNF is {proportional_to}68 kJmol{sup -1}, whereas that for pristine LiAlH{sub 4} it is 107 kJ/mol. The activation energy calculated for as synthesized LiMg(AlH{sub 4}){sub 3} is {proportional_to}66 kJ/mol. Since the first step decomposition of LiMg(AlH{sub 4}){sub 3} occurs during GNF admixing, the activation energy for initial step decomposition of GNF admixed LiMg(AlH{sub 4}){sub 3} could not be estimated. (orig.)

  16. A Novel Method for Making NiO Nanofibres via An Electrospinning Technique

    Institute of Scientific and Technical Information of China (English)

    Chang Lu SHAO; Hong Yu GUAN; Shang Bin WEN; Bin CHEN; Xing Hua YANG; Jian GONG

    2004-01-01

    Thin PVA/nickel acetate composite fibres were prepared by using sol-gel processing and electrospinning technique. After calcination of the above precursor fibres, NiO nanofibres with a diameter of 50-150 nm could be successfully obtained. The fibres were characterized by SEM, FT-IR, WAXD, respectively.

  17. Direct fabrication of hybrid nanofibres composed of SiO2-PMMA nanospheres via electrospinning.

    Science.gov (United States)

    Zhang, Ran; Shang, Tinghua; Yang, Guang; Jia, Xiaolong; Cai, Qing; Yang, Xiaoping

    2016-08-01

    The direct fabrication of hybrid nanofibres composed of poly(methyl methacrylate)-grafted SiO2 (SiO2-PMMA) nanospheres via electrospinning was investigated in detail. SiO2-PMMA nanospheres were successfully prepared, with the SiO2 nanospheres synthesized via the Stober method, followed by in situ surface-initiated atom transfer radical polymerization of methyl methacrylate (MMA). Electrospinning was carried out with N,N-dimethylformamide (DMF) as the solvent to disperse SiO2-PMMA nanospheres. The size of the SiO2 core, the molecular weight of the PMMA shell and the concentration of the SiO2-PMMA/DMF solution all had substantial effects on the morphology and structure of electrospun nanofibres composed of SiO2-PMMA nanospheres. When these determining factors were well-tailored, it was found that one-dimensional necklace-like nanofibres were obtained, with SiO2-PMMA nanospheres aligned one by one along the fibre. The successful fabrication of nanofibres by directly electrospinning the SiO2-PMMA/DMF solution verified that polymer-grafted particles possess polymer-like characteristics, which endowed them with the ability to be processed into desirable shapes and structures.

  18. Superhydrophobic PVDF and PVDF-HFP nanofibrous mats with antibacterial and anti-biofouling properties

    Energy Technology Data Exchange (ETDEWEB)

    Spasova, M.; Manolova, N. [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St, bl. 103A, BG-1113 Sofia (Bulgaria); Markova, N. [Institute of Microbiology, Bulgarian Academy of Sciences, Acad. G. Bonchev St, bl. 26, BG-1113 Sofia (Bulgaria); Rashkov, I., E-mail: rashkov@polymer.bas.bg [Laboratory of Bioactive Polymers, Institute of Polymers, Bulgarian Academy of Sciences, Acad. G. Bonchev St, bl. 103A, BG-1113 Sofia (Bulgaria)

    2016-02-15

    Graphical abstract: - Highlights: • New PVDF and PVDF-HFP nanofibers decorated with ZnO nanoparticles and a model drug. • The nanofibrous materials were fabricated by one-pot electrospinning. • The obtained materials are superhybrophobic and possess antibacterial properties. - Abstract: Superhydrophobic nanofibrous materials of poly(vinylidene fluoride) (PVDF) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) were prepared by one-pot electrospinning technique. The mats were decorated with ZnO nanoparticles with silanized surface and a model drug – 5-chloro-8-hydroxyquinolinol (5Cl8HQ). The obtained hybrid nanofibrous materials were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle measurements, mechanical and microbiological tests. The results showed that the incorporation of ZnO nanoparticles into PVDF and PVDF-HFP nanofibers increased the hydrophobicity (contact angle 152°), improved the thermal stability and imparted to the nanofibrous materials anti-adhesive and antimicrobial properties. The mats containing the model drug possessed antibacterial activity against Escherichia coli and Staphylococcus aureus. The results suggested that the obtained hybrid mats could find potential biomedical applications requiring antibacterial and anti-biofouling properties.

  19. Electrospun chitosan/baker’s yeast nanofibre adsorbent: preparation, characterization and application in heavy metal adsorption

    Indian Academy of Sciences (India)

    MASUME HOSSEINI; ALI REZA KESHTKAR; MOHAMMAD ALI MOOSAVIAN

    2016-08-01

    In this study, chitosan/baker’s yeast nanofibre was synthesized by electrospinning method and subsequently, the performance of the prepared nanofibre for removal of uranium(VI) and thorium(IV) ions from aqueous solutions was investigated. The prepared adsorbent was characterized by Brunauer–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses. The influences of experimental parameters on the chitosan/baker’s yeast nanofibre such as contact time, pH, temperature and initial concentration were studied in a batch system. The adsorption kinetics was studied by the pseudo-firstorder, pseudo-second-order, double-exponential and intra-particle kinetic models. Three isotherm models, namely Langmuir, Freundlich and Dubinin–Radushkevich (D–R) were used for analysis of equilibrium data of heavymetals. The maximum adsorption capacities of U(VI) and Th(IV) were estimated by Langmuir model to be 219 and 131.9 mg g$^{−1}$ at optimum conditions, respectively. The positive values of the enthalpy changes and negative values of Gibbs free energy changes showed that U(VI) and Th(IV) adsorption process was endothermic and spontaneous. Also, the inhibitory effect of Co(II), Cu(II), Cd(II), Fe(II) and Ni(II) metal ions on U(VI) and Th(IV) adsorption was investigated. The reusability of chitosan/baker’s yeast nanofibre was determined after five adsorption–desorption cycles.

  20. Investigation of the pore geometrical structure of nanofibrous membranes using statistical modelling

    Science.gov (United States)

    Khanmohammadi Khoshui, Sedigheh; Hosseini Ravandi, Seyed Abdolkarim; Bagherzadeh, Roohollah; Saberi, Zahra; Karimi, Mohammad

    2016-10-01

    The pore size and its distribution are the two main geometrical properties of nanofibrous membranes in various applications such as filtration and tissue engineering. In the current paper, a modified approach (model) is suggested to predict pore size and its distribution in nanofibrous membranes. In the present work, inter-fibre pores are considered as polygons arising from the fibre contacts. For the first time, these polygons are assumed to be three-, four- and five-gons, and the hydraulic radius of the pores was obtained instead of the equal radius. The pore size of multilayer mats was provided with a different insight. The pore mean size and its distribution were obtained by statistical methods. In order to validate the model, polycaprolactone (PCL) nanofibrous mats were electrospun, and the mean pore size and its distribution were measured using porosimetry. It was found that the probability distribution function of the pore size in both single and multi nanofibrous layers was the Gamma function with two parameters. The effect of the fibre width and porosity raise was increasing of mean pore diameter of multilayer networks. A comparison between the modified model and previous models revealed that the modified approach was more realistic.

  1. Preparation and gas-sensing property of parallel-aligned ZnO nanofibrous films

    Indian Academy of Sciences (India)

    Zikui Bai; Weilin Xu; Changsheng Xie; Mingchao Dong; Shunping Zhang; Jie Xu; Shili Xiao

    2013-08-01

    Parallel-aligned zinc oxide (ZnO) nanofibrous films fabricated by using electrospinning technique were used in gas sensors for the detection of ethanol and formaldehyde. The morphologies and crystal structures of the films were characterized by field-emission scanning electron microscopy (FE–SEM) and X-ray diffraction (XRD), respectively. FE–SEM results showed that ZnO nanofibres had an approximate diameter of 100–300 nm and consisted of hexagonal wurtzite structure ZnO nanocrystals with a primary particle diameter of 20–50 nm. The results of resistance–temperature characteristics and responses to ethanol and formaldehyde indicated that the parallelaligned ZnO nanofibrous film had a low activation energy (0.246 eV), a low optimum operating temperature and a high response. The response and recovery had a high rate in the initial stage and a low rate in the later stage. The parallel-aligned ZnO nanofibrous film had excellent potential application for formaldehyde sensor.

  2. Dynamics of nanofibres conveyed by low Reynolds number flow in a microchannel

    Energy Technology Data Exchange (ETDEWEB)

    Sadlej, K.; Wajnryb, E.; Ekiel-Jezewska, M.L.; Lamparska, D. [IPPT PAN, Polish Academy of Sciences, Pawinskiego 5B, 02-106 Warsaw (Poland); Kowalewski, T.A., E-mail: tkowale@ippt.gov.p [IPPT PAN, Polish Academy of Sciences, Pawinskiego 5B, 02-106 Warsaw (Poland)

    2010-12-15

    In this paper we aim to create an experimental and numerical model of nano and micro filaments suspended in a confined Poiseuille flow. The experimental data obtained for short nanofibres will help to elucidate fundamental questions concerning mobility and deformation of biological macromolecules due to hydrodynamic stresses from the surrounding fluid motion. Nanofibres used in the experiments are obtained by electrospinning polymer solutions. Their typical dimensions are 100-1000 {mu}m (length) and 0.1-1 {mu}m (diameter). The nanofibre dynamics is followed experimentally under a fluorescence microscope. A precise multipole expansion method of solving the Stokes equations, and its numerical implementation are used to construct a bead-spring model of a filament moving in a Poiseuille flow between two infinite parallel walls. Simulations show typical behaviour of elongated macromolecules. Depending on the parameters, folding and unfolding sequences of a flexible filament are observed, or a rotational and translation motion of a shape-preserving filament. An important result of our experiments is that nanofibres do not significantly change their shape while interacting with a micro-flow. It appeared that their rotational motion is better reproduced by the shape-preserving Stokesian bead model with all pairs of beads connected by springs, omitting explicit bending forces.

  3. Pcl/Chitosan Blended Nanofibrous Tubes Made by Dual Syringe Electrospinning

    Directory of Open Access Journals (Sweden)

    Hild Martin

    2015-03-01

    Full Text Available 3D tubular scaffolds made from Poly-(Ɛ-caprolactone (PCL/chitosan (CS nanofibres are very promising candidate as vascular grafts in the field of tissue engineering. In this work, the fabrication of PCL/CS-blended nanofibrous tubes with small diameters by electrospinning from separate PCL and CS solutions is studied. The influence of different CS solutions (CS/polyethylene glycol (PEO/glacial acetic acid (AcOH, CS/trifluoroacetic acid (TFA, CS/ AcOH on fibre formation and producibility of nanofibrous tubes is investigated. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR is used to verify the presence of CS in the blended samples. Tensile testing and pore size measurements are done to underline the good prerequisites of the fabricated blended PCL/ CS nanofibrous tubes as potential scaffolds for vascular grafts. Tubes fabricated from the combination of PCL and CS dissolved in AcOH possesses properties, which are favourable for future cell culture studies.

  4. A Stem Cell-Seeded Nanofibrous Scaffold for Auditory Nerve Replacement

    Science.gov (United States)

    2013-10-01

    biopolymer scaffold within the internal auditory meatus (IAM) of the guinea pig. (A) The lateral wall of an intact guinea pig temporal bone is shown......Nanofibrous Scaffold for Auditory Nerve Replacement 5b. GRANT NUMBER W81XWH-12-1-0492 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Betty Diamond

  5. Electrochemical biosensors based on nanofibres for cardiac biomarker detection: A comprehensive review.

    Science.gov (United States)

    Rezaei, Babak; Ghani, Mozhdeh; Shoushtari, Ahmad Mousavi; Rabiee, Mohammad

    2016-04-15

    The vital importance of early and accurate diagnosis of cardiovascular diseases (CVDs) to prevent the irreversible damage or even death of patients has driven the development of biosensor devices for detection and quantification of cardiac biomarkers. Electrochemical biosensors offer rapid sensing, low cost, portability and ease of use. Over the past few years, nanotechnology has contributed to a tremendous improvement in the sensitivity of biosensors. In this review, the authors summarise the state-of-the-art of the application of one particular type of nanostructured material, i.e. nanofibres, for use in electrochemical biosensors for the ultrasensitive detection of cardiac biomarkers. A new way of classifying the nanofibre-based electrochemical biosensors according to the electrical conductance and the type of nanofibres is presented. Some key data from each article reviewed are highlighted, including the mechanism of detection, experimental conditions and the response range of the biosensor. The primary aim of this review is to emphasise the prospects for nanofibres for the future development of biosensors in diagnosis of CVDs as well as considering how to improve their characteristics for application in medicine.

  6. Nanofibrous nerve conduits for repair of 30-mm-long sciatic nerve defects*

    Institute of Scientific and Technical Information of China (English)

    Esmaeil Biazar; Saeed Heidari Keshel; Majid Pouya; Hadi Rad; Melody Omrani Nava; Mohammad Azarbakhsh; Shirin Hooshmand

    2013-01-01

    It has been confirmed that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit can promote peripheral nerve regeneration in rats. However, its efficiency in repair of over 30-mm-long sciatic nerve defects needs to be assessed. In this study, we used a nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit to bridge a 30-mm-long gap in the rat sciatic nerve. At 4 months after nerve conduit implantation, regenerated nerves were macroscopi-cal y observed and histological y assessed. In the nanofibrous graft, the rat sciatic nerve trunk had been reconstructed by restoration of nerve continuity and formation of myelinated nerve fiber. There were Schwann cel s and glial cel s in the regenerated nerves. Masson’s trichrome staining showed that there were no pathological changes in the size and structure of gastrocnemius muscle cel s on the operated side of rats. These findings suggest that nanofibrous poly(3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit is suitable for repair of long-segment sciatic nerve defects.

  7. Electrospun Polyamide 4.6 Nanofibrous Nonwovens: Parameter Study and Characterization

    Directory of Open Access Journals (Sweden)

    Bert De Schoenmaker

    2012-01-01

    Full Text Available The aliphatic polyamide 4.6 (PA 4.6 has unique properties compared to the commonly used polyamides 6 (PA 6 and 6.6 (PA 6.6. The purpose of this paper is to produce uniform and reproducible nanofibrous PA 4.6 structures. Therefore, a mixture of the solvent formic acid and the nonsolvent acetic acid is used to dissolve and electrospin the PA 4.6. First the steady-state behaviour of the process and the boundary limits of the solution parameters needed for steady-state electrospinning are investigated. Subsequently, the effect of several solution and process parameters on the fibre morphology is examined, using microscopic techniques and thermal analysis. The polyamide concentration is found to be the dominant parameter affecting the fibre diameter and morphology. Furthermore, tensile tests are performed on upscaled nanofibrous structures and electrospun under optimised steady-state conditions. It is shown that the PA 4.6 nanofibrous structures, compared to nanofibrous nonwovens of PA 6 and PA 6.6, have a higher stress and strain at break.

  8. Biocompatibility and degradation characteristics of PLGA-based electrospun nanofibrous scaffolds with nanoapatite incorporation.

    NARCIS (Netherlands)

    Ji, W.; Yang, F.; Seyednejad, H.; Chen, Z.; Hennink, W.E.; Anderson, J.M.; Beucken, J.J.J.P van den; Jansen, J.A.

    2012-01-01

    The aim of current study was to evaluate the effect of nano-apatitic particles (nAp) incorporation on the degradation characteristics and biocompatibility of poly(lactide-co-glycolide) (PLGA)-based nanofibrous scaffolds. Composite PLGA/poly(varepsilon-caprolactone) (PCL) blended (w/w = 3/1) polymeri

  9. Modification of PLGA Nanofibrous Mats by Electron Beam Irradiation for Soft Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    Jae Baek Lee

    2015-01-01

    Full Text Available Biodegradable poly(lactide-co-glycolide (PLGA has found widespread use in modern medical practice. However, the degradation rate of PLGA should be adjusted for specific biomedical applications such as tissue engineering, drug delivery, and surgical implantation. This study focused on the effect of electron beam radiation on nanofibrous PLGA mats in terms of physical properties and degradation behavior with cell proliferation. PLGA nanofiber mats were prepared by electrospinning, and electron beam was irradiated at doses of 50, 100, 150, 200, 250, and 300 kGy. PLGA mats showed dimensional integrity after electron beam irradiation without change of fiber diameter. The degradation behavior of a control PLGA nanofiber (0 kGy and electron beam-irradiated PLGA nanofibers was analyzed by measuring the molecular weight, weight loss, change of chemical structure, and fibrous morphology. The molecular weight of the PLGA nanofibers decreased with increasing electron beam radiation dose. The mechanical properties of the PLGA nanofibrous mats were decreased with increasing electron beam irradiation dose. Cell proliferation behavior on all electron beam irradiated PLGA mats was similar to the control PLGA mats. Electron beam irradiation of PLGA nanofibrous mats is a potentially useful approach for modulating the biodegradation rate of tissue-specific nonwoven nanofibrous scaffolds, specifically for soft tissue engineering applications.

  10. A novel method for making ZrO 2 nanofibres via an electrospinning technique

    Science.gov (United States)

    Shao, Changlu; Guan, Hongyu; Liu, Yichun; Gong, Jian; Yu, Na; Yang, Xinghua

    2004-06-01

    Thin PVA/zirconium oxychloride composite fibres were prepared by using sol-gel processing and electrospinning technique. After calcinations of the above precursor fibres, ZrO 2 nanofibres with a diameter of 50-200 nm could be successfully obtained. The fibres were characterized by SEM, FT-IR, XRD, respectively.

  11. Antibacterial effects of electrospun chitosan/poly(ethylene oxide) nanofibrous membranes loaded with chlorhexidine and silver

    NARCIS (Netherlands)

    Song, J.; Remmers, S.J.; Shao, J.; Kolwijck, E.; Walboomers, X.F.; Jansen, J.A.; Leeuwenburgh, S.C.; Yang, F.

    2016-01-01

    To prevent percutaneous device associated infections (PDAIs), we prepared electrospun chitosan/poly(ethylene oxide) (PEO) nanofibrous membrane containing silver nanoparticles as an implantable delivery vehicle for the dual release of chlorhexidine and silver ions. We observed that the silver nanopar

  12. Antibacterial continuous nanofibrous hybrid yarn through in situ synthesis of silver nanoparticles: Preparation and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Barani, Hossein, E-mail: barani@birjand.ac.ir

    2014-10-01

    Nanofibrous hybrid yarns of polyvinyl alcohol (PVA) and poly-L-lactide acid (PLLA) with the antibacterial activity were prepared that contains 0, 5, 10, 20, and 30 wt.% of silver nanoparticles according to the PVA polymer content. This was performed by electrospinning using distilled water and 2, 2, 2-trifluoroethanol as a solvent for PVA and PLLA respectively, and sodium borohydride was used as a reducing agent. The scanning electron microscope observation confirmed the formation of AgNPs into the PVA nanofiber structure, and they were uniform, bead free, cylindrical and smooth. The diameter of hybrid yarns and their nanofiber component was decreased as the silver nitrate concentration in electrospinning solutions was increased. The differential scanning calorimetry results indicated that the silver nanoparticles can form interactions with polymer chains and decrease the melting enthalpy. The mechanical analysis showed a lower stress and strain at break of the AgNP-loaded nanofibrous hybrid yarns than the unloaded hybrid yarn. However, there wasn't a statistically significant difference between the strain at break of electrospun nanofibrous hybrid yarns. Moreover, the bactericidal efficiency of all loaded samples was over 99.99%. - Highlights: • Nanofibrous hybrid yarns of PVA/PLLA with antibacterial activity were prepared. • The diameter of nanofibers was decreased as the AgNP concentration was increased. • AgNPs make interactions with amorphous phase of polymer and increase the Tg. • All loaded samples presented a good bactericidal and bacteriostatic efficiency.

  13. Bacteria encapsulated electrospun nanofibrous webs for remediation of methylene blue dye in water.

    Science.gov (United States)

    Sarioglu, Omer Faruk; Keskin, Nalan Oya San; Celebioglu, Asli; Tekinay, Turgay; Uyar, Tamer

    2017-04-01

    In this study, preparation and application of novel biocomposite materials that were produced by encapsulation of bacterial cells within electrospun nanofibrous webs are described. A commercial strain of Pseudomonas aeruginosa which has methylene blue (MB) dye remediation capability was selected for encapsulation, and polyvinyl alcohol (PVA) and polyethylene oxide (PEO) were selected as the polymer matrices for the electrospinning of bacteria encapsulated nanofibrous webs. Encapsulation of bacterial cells was monitored by scanning electron microscopy (SEM) and fluorescence microscopy, and the viability of encapsulated bacteria was checked by live/dead staining and viable cell counting assay. Both bacteria/PVA and bacteria/PEO webs have shown a great potential for remediation of MB, yet bacteria/PEO web has shown higher removal performances than bacteria/PVA web, which was probably due to the differences in the initial viable bacterial cells for those two samples. The bacteria encapsulated electrospun nanofibrous webs were stored at 4°C for three months and they were found as potentially storable for keeping encapsulated bacterial cells alive. Overall, the results suggest that electrospun nanofibrous webs are suitable platforms for preservation of living bacterial cells and they can be used directly as a starting inoculum for bioremediation of water systems.

  14. Electrospun poly(L-lactide/poly(ε-caprolactone blend nanofibrous scaffold: characterization and biocompatibility with human adipose-derived stem cells.

    Directory of Open Access Journals (Sweden)

    Liang Chen

    Full Text Available The essence of tissue engineering is the fabrication of autologous cells or induced stem cells in naturally derived or synthetic scaffolds to form specific tissues. Polymer is thought as an appealing source of cell-seeded scaffold owing to the diversity of its physicochemical property and can be electrospun into nano-size to mimic natural structure. Poly (L-lactic acid (PLLA and poly (ε-caprolactone (PCL are both excellent aliphatic polyester with almost "opposite" characteristics. The controlling combination of PLLA and PCL provides varying properties and makes diverse applications. Compared with the copolymers of the same components, PLLA/PCL blend demonstrates its potential in regenerative medicine as a simple, efficient and scalable alternative. In this study, we electrospun PLLA/PCL blends of different weight ratios into nanofibrous scaffolds (NFS and their properties were detected including morphology, porosity, degradation, ATR-FTIR analysis, stress-stain assay, and inflammatory reaction. To explore the biocompatibility of the NFS we synthesized, human adipose-derived stem cells (hASCs were used to evaluate proliferation, attachment, viability and multi-lineage differentiation. In conclusion, the electrospun PLLA/PCL blend nanofibrous scaffold with the indicated weight ratios all supported hASCs well. However, the NFS of 1/1 weight ratio showed better properties and cellular responses in all assessments, implying it a biocompatible scaffold for tissue engineering.

  15. Transcription of Nanofibrous Cerium Phosphate Using a pH-Sensitive Lipodipeptide Hydrogel Template

    Directory of Open Access Journals (Sweden)

    Mario Llusar

    2017-06-01

    Full Text Available A novel and simple transcription strategy has been designed for the template-synthesis of CePO4·xH2O nanofibers having an improved nanofibrous morphology using a pH-sensitive nanofibrous hydrogel (glycine-alanine lipodipeptide as structure-directing scaffold. The phosphorylated hydrogel was employed as a template to direct the mineralization of high aspect ratio nanofibrous cerium phosphate, which in-situ formed by diffusion of aqueous CeCl3 and subsequent drying (60 °C and annealing treatments (250, 600 and 900 °C. Dried xerogels and annealed CePO4 powders were characterized by conventional thermal and thermogravimetric analysis (DTA/TG, and Wide-Angle X-ray powder diffraction (WAXD and X-ray powder diffraction (XRD techniques. A molecular packing model for the formation of the fibrous xerogel template was proposed, in accordance with results from Fourier-Transformed Infrarred (FTIR and WAXD measurements. The morphology, crystalline structure and composition of CePO4 nanofibers were characterized by electron microscopy techniques (Field-Emission Scanning Electron Microscopy (FE-SEM, Transmission Electron Microscopy/High-Resolution Transmission Electron Microscopy (TEM/HRTEM, and Scanning Transmission Electron Microscopy working in High Angle Annular Dark-Field (STEM-HAADF with associated X-ray energy-dispersive detector (EDS and Scanning Transmission Electron Microscopy-Electron Energy Loss (STEM-EELS spectroscopies. Noteworthy, this templating approach successfully led to the formation of CePO4·H2O nanofibrous bundles of rather co-aligned and elongated nanofibers (10–20 nm thick and up to ca. 1 μm long. The formed nanofibers consisted of hexagonal (P6222 CePO4 nanocrystals (at 60 and 250 °C, with a better-grown and more homogeneous fibrous morphology with respect to a reference CePO4 prepared under similar (non-templated conditions, and transformed into nanofibrous monoclinic monazite (P21/n around 600 °C. The nanofibrous morphology

  16. Efficient protein immobilization on polyethersolfone electrospun nanofibrous membrane via covalent binding for biosensing applications

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoudifard, Matin [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Soudi, Sara [Stem Cell Biology Department, Stem Cell Technology Research Center, Tehran (Iran, Islamic Republic of); Department of Immunology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Soleimani, Masoud [Department of Hematology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Hosseinzadeh, Simzar [Nanotechnology and Tissue Engineering Department, Stem Cell Technology Research Center, Tehran (Iran, Islamic Republic of); School of Advanced Medical Technologies, Tehran University of Medical Sciences, Tehran (Iran, Islamic Republic of); Esmaeili, Elaheh [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Department of Hematology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran (Iran, Islamic Republic of); Vossoughi, Manouchehr, E-mail: vosoughi@sharif.edu [Institute for Nanoscience and Nanotechnology, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Chemical and Petroleum Engineering Department, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2016-01-01

    In this paper we introduce novel strategy for antibody immobilization using high surface area electrospun nanofibrous membrane based on ethyl-3-(3-dimethylaminopropyl)-carbodiimide/N-hydroxysuccinimide (EDC/NHS) coupling chemistry. To present the high performance of proposed biosensors, anti-staphylococcus enterotoxin B (anti-SEB) was used as a model to demonstrate the utility of our proposed system. Polymer solution of polyethersolfone was used to fabricate fine nanofibrous membrane. Moreover, industrial polyvinylidene fluoride membrane and conventional microtiter plate were also used to compare the efficiency of antibody immobilization. Scanning electron microscopy images were taken to study the morphology of the membranes. The surface activation of nanofibrous membrane was done with the help of O{sub 2} plasma. PES nanofibrous membrane with carboxyl functional groups for covalent attachment of antibodies were treated by EDC/NHS coupling agent. The quantity of antibody immobilization was measured by enzyme-linked immuno sorbent assay (ELISA) method. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) spectroscopy was performed to confirm the covalent immobilization of antibody on membrane. Atomic force microscopy, scanning electron microscopy and invert fluorescence microscopy were used to analyze the antibody distribution pattern on solid surfaces. Results show that oxygen plasma treatment effectively increased the amount of antibody immobilization through EDC/NHS coupling chemistry. It was found that the use of nanofibrous membrane causes the improved detection signal of ELISA based biosensors in comparison to the standard assay carried out in the 96-well microtiter plate. This method has the potential to improve the ELISA-based biosensor and we believe that this technique can be used in various biosensing methods. - Highlights: • Introduction of novel strategy for antibody immobilization using high surface area electrospun

  17. Processing and Performance of MOF (Metal Organic Framework)-Loaded PAN Nanofibrous Membrane for CO2 Adsorption

    Science.gov (United States)

    Wahiduzzaman; Khan, Mujibur R.; Harp, Spencer; Neumann, Jeffrey; Sultana, Quazi Nahida

    2016-04-01

    The objective of this experimental study is to produce a nanofibrous membrane functionalized with adsorbent particles called metal organic framework (MOF) in order to adsorb CO2 from a gas source. Therefore, Polyacrylonitrile (PAN) was chosen as the precursor for nanofibers and HKUST-1, a Cu-based MOF, was chosen as adsorbent. The experimental process consists of electrospinning PAN solution blended with HKUST-1 to produce a nanofibrous mat as working substrates. The fibers were collected in a cylindrical canister model. SEM image of this mat showed nanofibers with the presence of small adsorbent particles, impregnated into the as-spun fibers discretely. To increase the amount of MOF particles for effectual gas adsorption, a secondary solvothermal process of producing MOF particles on the fibers was required. This process consists of multiple growth cycles of HKUST-1 particles by using a sol-gel precursor. SEM images showed uniform distribution of porous MOF particles of 2-4 µm in size on the fiber surface. Energy dispersive spectroscopy report of the fiber confirmed the presence of MOF particles through the identification of characteristic Copper elemental peaks of HKUST-1. To determine the thermal stability of the fibrous membrane, Thermogravimetric analysis of HKUST-1 consisting of PAN fiber was performed where a total weight loss of 40% between 210 and 360 °C was observed, hence proving the high-temperature durability of the synthesized membrane. BET surface area of the fiber membrane was measured as 540.73 m2/g. The fiber membrane was then placed into an experimental test bench containing a mixed gas inflow of CO2 and N2. Using non-dispersive infrared CO2 sensors connected to the inlet and outlet port of the bench, significant reduction of CO2 in concentration was measured. Comparative IR spectroscopic analysis between the gas-treated and gas untreated fiber samples showed the presence of characteristic peak in the vicinity of 2300 and 2400 cm-1 which

  18. An in vitro model of the glomerular capillary wall using electrospun collagen nanofibres in a bioartificial composite basement membrane.

    Directory of Open Access Journals (Sweden)

    Sadie C Slater

    Full Text Available The filtering unit of the kidney, the glomerulus, contains capillaries whose walls function as a biological sieve, the glomerular filtration barrier. This comprises layers of two specialised cells, glomerular endothelial cells (GEnC and podocytes, separated by a basement membrane. Glomerular filtration barrier function, and dysfunction in disease, remains incompletely understood, partly due to difficulties in studying the relevant cell types in vitro. We have addressed this by generation of unique conditionally immortalised human GEnC and podocytes. However, because the glomerular filtration barrier functions as a whole, it is necessary to develop three dimensional co-culture models to maximise the benefit of the availability of these cells. Here we have developed the first two tri-layer models of the glomerular capillary wall. The first is based on tissue culture inserts and provides evidence of cell-cell interaction via soluble mediators. In the second model the synthetic support of the tissue culture insert is replaced with a novel composite bioartificial membrane. This consists of a nanofibre membrane containing collagen I, electrospun directly onto a micro-photoelectroformed fine nickel supporting mesh. GEnC and podocytes grew in monolayers on either side of the insert support or the novel membrane to form a tri-layer model recapitulating the human glomerular capillary in vitro. These models will advance the study of both the physiology of normal glomerular filtration and of its disruption in glomerular disease.

  19. Optical nanofibre integrated into an optical tweezers for particle manipulation, in situ fibre probing, and optical binding studies

    CERN Document Server

    Gusachenko, Ivan; Frawley, Mary C; Chormaic, Síle Nic

    2015-01-01

    Precise control of particle positioning is desirable in many optical propulsion and sorting applications. Here, we develop an integrated platform for particle manipulation consisting of a combined optical nanofibre and optical tweezers system. Individual silica microspheres were introduced to the nanofibre at arbitrary points using the optical tweezers, thereby producing pronounced dips in the fibre transmission. We show that such consistent and reversible transmission modulations depend on both particle and fibre diameter, and can be used as a reference point for in situ nanofibre or particle size measurement. Thence, we combine scanning electron microscope (SEM) size measurements with nanofibre transmission data to provide calibration for particle-based fibre assessment. This integrated optical platform provides a method for selective evanescent field manipulation of micron-sized particles and facilitates studies of optical binding and light-particle interaction dynamics.

  20. SU-8 photoresist-derived electrospun carbon nanofibres as high-capacity anode material for lithium ion battery

    Indian Academy of Sciences (India)

    M KAKUNURI; S KAUSHIK; A SAINI; C S SHARMA

    2017-06-01

    A binder-free carbon nanofibres web over stainless-steel wafer current collector was fabricated by controlled pyrolysis of electrospun SU-8 photoresist nanofibres. Electrochemical performance of the as-prepared carbon nanofibresweb was investigated by performing charge–discharge experiments at different current densities. At low current density (37.2 mA g$^{−1}, 0.1$C$), SU-8-derived carbon nanofabric showed a large initial discharge capacity (1417 mAh g$^{−1}$) with sufficiently higher initial coulombic efficiency ($\\sim$55%). More importantly, this carbon nanofibres web also exhibited excellent rate performance with considerably higher specific capacities at higher current densities (358 mAh g$^{−1}$ at 1C). This superior electrochemical performance, in particular at high current rates, can be attributed to small lithium ion diffusion length andresilience in entangled carbon nanofibres to accommodate volume changes during charging and discharging.

  1. Fabrication of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} superconducting nanofibres by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Cui Xuemei [Department of Advanced Organic Materials and Textile System Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Lyoo, Won Seok [School of Textiles, Yeungnam University, Kyungsan-city 712-429 (Korea, Republic of); Son, Won Keun [Research Institute of Advanced Materials, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Park, Dae Hun [Division of Nano Science, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Choy, Jin Ho [Division of Nano Science, Ewha Womans University, Seoul 120-750 (Korea, Republic of); Lee, Taek Seung [Department of Advanced Organic Materials and Textile System Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Park, Won Ho [Department of Advanced Organic Materials and Textile System Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2006-12-15

    YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} superconducting nanofibres were successfully fabricated via the electrospinning method in combination with the sol-gel process. The solution was prepared by the sol-gel process with a homogeneous aqueous PVA solution containing Y, Ba, and Cu acetates. The viscosity of the precursor sol for electrospinning was controlled by the evaporation of solvent and a condensation reaction. The electrospun nanofibres were pyrolysed to remove PVA or volatile components, and then sintered to generate a superconducting phase. The critical transition temperature (T{sub c}) of superconducting YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} nanofibres was measured by DC susceptibility tests. By optimizing the electrospinning process and following heat treatments, superconducting YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} nanofibres with a T{sub c} = 92.2 K could be produced.

  2. The influence of substrate temperature on growth of para-sexiphenyl thin films on Ir{111} supported graphene studied by LEEM

    Science.gov (United States)

    Khokhar, Fawad S.; Hlawacek, Gregor; van Gastel, Raoul; Zandvliet, Harold J. W.; Teichert, Christian; Poelsema, Bene

    2012-02-01

    The growth of para-sexiphenyl (6P) thin films as a function of substrate temperature on Ir{111} supported graphene flakes has been studied in real-time with Low Energy Electron Microscopy (LEEM). Micro Low Energy Electron Diffraction (μLEED) has been used to determine the structure of the different 6P features formed on the surface. We observe the nucleation and growth of a wetting layer consisting of lying molecules in the initial stages of growth. Graphene defects - wrinkles - are found to be preferential sites for the nucleation of the wetting layer and of the 6P needles that grow on top of the wetting layer in the later stages of deposition. The molecular structure of the wetting layer and needles is found to be similar. As a result, only a limited number of growth directions are observed for the needles. In contrast, on the bare Ir{111} surface 6P molecules assume an upright orientation. The formation of ramified islands is observed on the bare Ir{111} surface at 320 K and 352 K, whereas at 405 K the formation of a continuous layer of upright standing molecules growing in a step flow like manner is observed.

  3. Effects of Chitosan Alkali Pretreatment on the Preparation of Electrospun PCL/Chitosan Blend Nanofibrous Scaffolds for Tissue Engineering Application

    OpenAIRE

    Fatemeh Roozbahani; Naznin Sultana; Ahmad Fauzi Ismail; Hamed Nouparvar

    2013-01-01

    Recently, nanofibrous scaffolds have been used in the field of biomedical engineering as wound dressings, tissue engineering scaffolds, and drug delivery applications. The electrospun nanofibrous scaffolds can be used as carriers for several types of drugs, genes, and growth factors. PCL is one of the most commonly applied synthetic polymers for medical use because of its biocompatibility and slow biodegradability. PCL is hydrophobic and has no cell recognition sites on its structure. Electro...

  4. Precipitation of hydroxyapatite on electrospun polycaprolactone/aloe vera/silk fibroin nanofibrous scaffolds for bone tissue engineering.

    Science.gov (United States)

    Shanmugavel, Suganya; Reddy, Venugopal Jayarama; Ramakrishna, Seeram; Lakshmi, B S; Dev, Vr Giri

    2014-07-01

    Advances in electrospun nanofibres with bioactive materials have enhanced the scope of fabricating biomimetic scaffolds for tissue engineering. The present research focuses on fabrication of polycaprolactone/aloe vera/silk fibroin nanofibrous scaffolds by electrospinning followed by hydroxyapatite deposition by calcium-phosphate dipping method for bone tissue engineering. Morphology, composition, hydrophilicity and mechanical properties of polycaprolactone/aloe vera/silk fibroin-hydroxyapatite nanofibrous scaffolds along with controls polycaprolactone and polycaprolactone/aloe vera/silk fibroin nanofibrous scaffolds were examined by field emission scanning electron microscopy, Fourier transform infrared spectroscopy, contact angle and tensile tests, respectively. Adipose-derived stem cells cultured on polycaprolactone/aloe vera/silk fibroin-hydroxyapatite nanofibrous scaffolds displayed highest cell proliferation, increased osteogenic markers expression (alkaline phosphatase and osteocalcin), osteogenic differentiation and increased mineralization in comparison with polycaprolactone control. The obtained results indicate that polycaprolactone/aloe vera/silk fibroin-hydroxyapatite nanofibrous scaffolds have appropriate physico-chemical and biological properties to be used as biomimetic scaffolds for bone tissue regeneration.

  5. Curcumin- and natural extract-loaded nanofibres for potential treatment of lung and breast cancer: in vitro efficacy evaluation.

    Science.gov (United States)

    Sridhar, Radhakrishnan; Ravanan, Swamy; Venugopal, Jayarama Reddy; Sundarrajan, Subramanian; Pliszka, Damian; Sivasubramanian, S; Gunasekaran, P; Prabhakaran, Mohana; Madhaiyan, Kalaipriya; Sahayaraj, Arockia; Lim, Keith Hsiu Chin; Ramakrishna, Seeram

    2014-07-01

    Drug-eluting medical implants are more common, particularly for fighting against cancers. FDA and other drug regulatory bodies have approved many nanoformulated devices eluting active pharmaceutical ingredients and thus there is growing demand for further value- added devices. Nanofibre membranes are known for its versatility of drug incorporation and sustained drug release. We intend to fabricate natural ingredient or extract, and their combination loaded polycaprolactone (PCL) nanofibre for usage as drug-eluting stents or implants for anticancer activity against lung and breast cancers. The fabricated nanofibre membranes were characterised by scanning electron microscope for morphology, FT-IR for chemical nature and tensile testing for mechanical strengths. Release of curcumin was studied with time to find the applicability of the device as drug-eluting implant. The activity of the nanofibre membranes was tested against human breast cancer (MCF7) and lung cancer (A459) cell lines in vitro. In both the cell lines tested, 1% aloe vera and 5% curcumin-loaded PCL nanofibre exhibited 15% more cytotoxicity in comparison with the commercial drug 1% cis-Platin-loaded PCL nanofibre after 24 h incubation.

  6. Soluplus graft copolymer: potential novel carrier polymer in electrospinning of nanofibrous drug delivery systems for wound therapy.

    Science.gov (United States)

    Paaver, Urve; Tamm, Ingrid; Laidmäe, Ivo; Lust, Andres; Kirsimäe, Kalle; Veski, Peep; Kogermann, Karin; Heinämäki, Jyrki

    2014-01-01

    Electrospinning is an effective method in preparing polymeric nanofibrous drug delivery systems (DDSs) for topical wound healing and skin burn therapy applications. The aim of the present study was to investigate a new synthetic graft copolymer (Soluplus) as a hydrophilic carrier polymer in electrospinning of nanofibrous DDSs. Soluplus (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (PCL-PVAc-PEG)) was applied in the nonwoven nanomats loaded with piroxicam (PRX) as a poorly water-soluble drug. Raman spectroscopy, X-ray powder diffraction, differential scanning calorimetry, and scanning electron microscopy (SEM) were used in the physical characterization of nanofibrous DDSs. According to the SEM results, the drug-loaded PCL-PVAc-PEG nanofibers were circular in cross-section with an average diameter ranging from 500 nm up to 2  µm. Electrospinning stabilized the amorphous state of PRX. In addition, consistent and sustained-release profile was achieved with the present nanofibrous DDSs at the physiologically relevant temperature and pH applicable in wound healing therapy. In conclusion, electrospinning can be used to prepare nanofibrous DDSs of PCL-PVAc-PEG graft copolymer (Soluplus) and to stabilize the amorphous state of a poorly water-soluble PRX. The use of this synthetic graft copolymer can open new options to formulate nanofibrous DDSs for wound healing.

  7. Amine-functionalized PVA-co-PE nanofibrous membrane as affinity membrane with high adsorption capacity for bilirubin.

    Science.gov (United States)

    Wang, Wenwen; Zhang, Hao; Zhang, Zhifeng; Luo, Mengying; Wang, Yuedan; Liu, Qiongzhen; Chen, Yuanli; Li, Mufang; Wang, Dong

    2017-02-01

    In this study, poly(vinyl alcohol-co-ethylene) (PVA-co-PE) nanofibrous membrane was activated by sodium hydroxide and cyanuric chloride, and then the activated membranes were functionalized by 1,3-propanediamine, hexamethylenediamine and diethylenetriamine to be affinity membranes for bilirubin removal, respectively. The chemical structures and morphologies of membranes were investigated by SEM, FTIR and XPS. And the adsorption ability of different amine-functionalized nanofibrous membranes for bilirubin was characterized. Furthermore, the effects of temperature, initial concentration of bilirubin, NaCl concentration and BSA concentration on the adsorption capacity for bilirubin of diethylenetriamine-functionalized nanofibrous membrane were studied. Results indicated that the adsorption capacity for bilirubin of diethylenetriamine-functionalized nanofibrous membrane could reach 85mg/g membrane when the initial bilirubin concentration was 200mg/L while the adsorption capacity could be increased to 110mg/g membrane if the initial bilirubin concentration was more than 400mg/L. The dynamic adsorption of diethylenetriamine-functionalized nanofibrous membrane showed that the ligands of amine groups on the membrane surface could be used as far as possible by recirculating the plasma with certain flow rates. Therefore, the diethylenetriamine-functionalized PVA-co-PE nanofibrous membrane possessed high adsorption capacity for bilirubin and it can be candidate as affinity membrane for bilirubin removal.

  8. Soluplus Graft Copolymer: Potential Novel Carrier Polymer in Electrospinning of Nanofibrous Drug Delivery Systems for Wound Therapy

    Directory of Open Access Journals (Sweden)

    Urve Paaver

    2014-01-01

    Full Text Available Electrospinning is an effective method in preparing polymeric nanofibrous drug delivery systems (DDSs for topical wound healing and skin burn therapy applications. The aim of the present study was to investigate a new synthetic graft copolymer (Soluplus as a hydrophilic carrier polymer in electrospinning of nanofibrous DDSs. Soluplus (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer (PCL-PVAc-PEG was applied in the nonwoven nanomats loaded with piroxicam (PRX as a poorly water-soluble drug. Raman spectroscopy, X-ray powder diffraction, differential scanning calorimetry, and scanning electron microscopy (SEM were used in the physical characterization of nanofibrous DDSs. According to the SEM results, the drug-loaded PCL-PVAc-PEG nanofibers were circular in cross-section with an average diameter ranging from 500 nm up to 2 µm. Electrospinning stabilized the amorphous state of PRX. In addition, consistent and sustained-release profile was achieved with the present nanofibrous DDSs at the physiologically relevant temperature and pH applicable in wound healing therapy. In conclusion, electrospinning can be used to prepare nanofibrous DDSs of PCL-PVAc-PEG graft copolymer (Soluplus and to stabilize the amorphous state of a poorly water-soluble PRX. The use of this synthetic graft copolymer can open new options to formulate nanofibrous DDSs for wound healing.

  9. Supported plasma-made 1D heterostructures: perspectives and applications

    Energy Technology Data Exchange (ETDEWEB)

    Borras, Ana; Macias-Montero, Manuel; Romero-Gomez, Pablo; Gonzalez-Elipe, Agustin R, E-mail: anaisabel.borras@icmse.csic.es [Materials Science Institute of Seville (CSIC-Universidad Sevilla), C/Americo Vespucio 49 41092, Sevilla (Spain)

    2011-05-04

    Plasma-related methods have been widely used in the fabrication of carbon nanotubes and nanofibres (NFs) and semiconducting inorganic nanowires (NWs). A natural progression of the research in the field of 1D nanostructures is the synthesis of multicomponent NWs and NFs. In this paper we review the state of the art of the fabrication by plasma methods of 1D heterostructures including applications and perspectives. Furthermore, recent developments on the use of metal seeds (Ag, Au, Pt) to obtain metal-oxide nanostructures are also extensively described. Results are shown for various metal substrates, either metal foils or supported nanoparticles/thin films of the metal where the effects of the size, surface coverage, percolation degree and thickness of the metal seeds have been systematically evaluated. The possibilities of the process are illustrated by the preparation of nanostructured films and supported NFs of different metal-oxides (Ag, Au and SiO{sub 2}, TiO{sub 2}, ZnO). Particularly, in the case of silver, the application of an oxygen plasma treatment prior to the deposition of the oxide was critical for efficiently controlling the growth of the 1D heterostructures. A phenomenological model is proposed to account for the thin-film nanostructuring and fibre formation by considering basic phenomena such as stress relaxation, inhomogeneities in the plasma sheath electrical field and the local disturbance of the oxide growth.

  10. Integration of nondegradable polystyrene and degradable gelatin in a core–sheath nanofibrous patch for pelvic reconstruction

    Directory of Open Access Journals (Sweden)

    Ge LP

    2015-04-01

    Full Text Available Liangpeng Ge,1–5,* Qingtao Li,2,3,* Junzi Jiang,2,3 Xiaoyan You,1 Zuohua Liu,1 Wen Zhong,6 Yong Huang,1 Malcolm MQ Xing2,31Chongqing Academy of Animal Sciences, Chongqing, People’s Republic of China; 2Department of Mechanical and Manufacturing Engineering, Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, Canada; 3Manitoba Institute of Child Health, Winnipeg, MB, Canada; 4Key Laboratory of Pig Industry Sciences, Ministry of Agriculture,Chongqing, People’s Republic of China; 5Chongqing Key Laboratory of Pig Industry Sciences, Chongqing, People’s Republic of China; 6Department of Textile Sciences, Faculty of Human Ecology, University of Manitoba, Winnipeg, MB, Canada*These authors contributed equally to this workAbstract: Pelvic organ prolapse (POP is a serious health issue affecting many adult women. Complications of POP include pelvic pressure, pelvic pain, and problems in emptying their bowels or bladder. Sometimes, POP may even cause urinary outflow obstruction and lead to bladder or kidney infections. Currently, synthetic and naturally derived materials have been chosen for treatment of POP to reduce the high recurrence rates after surgical interventions. However, existing materials for POP treatment cannot meet the clinical requirements in terms of biocompatibility, mechanics, and minimal risk of rejection. Especially, erosion in synthetic polymers and rapid degradation in natural polymers limit their further applications in clinics. To address these concerns, we report a novel POP replacement using core–sheath polystyrene/gelatin electrospun nanofiber mesh. The outside gelatin sheath provides a hydrophilic surface and implantable integrity between host and guest, while the inner PS core offers the necessary mechanical support. The composite mesh shows graft accommodation in pelvic submucosa after implantation in vivo, as shown in hematoxylin–eosin staining and T helper cell phenotype and macrophage

  11. Hydrous ZrO2 decorated polyaniline nanofibres: Synthesis, characterization and application as an efficient adsorbent for water defluoridation.

    Science.gov (United States)

    Parashar, Kamya; Ballav, Niladri; Debnath, Sushanta; Pillay, Kriveshini; Maity, Arjun

    2017-08-16

    A new hybrid material comprising hydrous zirconium oxide (HZrO2) supported onto polyaniline (PANI) nanofibres (HZrO2@PANI NFs) was prepared via the precipitation of HZrO2 onto as-synthesized PANI NFs and tested for its defluoridation capabilities. The developed adsorbent (HZrO2@PANI NFs) was fully characterized by FTIR, BET, XRD, SEM-EDX, TEM-(S)TEM, XPS, and zeta potential measurements. HZrO2@PANI NFs achieved 2-fold BET surface area ∼86.64 m(2)/gas compared to PANI NFs ∼44.72 m(2)/g, implying that the incorporation of HZrO2 onto the PANI nanofibres enhanced the available surface area for effective fluoride adsorption. Moreover, HZrO2@PANI NFs was found to be effective over a wide pH range (3-9) as designated by its high pHpzc ∼9.8. The adsorption kinetics obeyed the pseudo-second-order model well with equilibrium attainment in 30min. Adsorption isotherm was best described by the Langmuir model and the maximum adsorption capacities obtained were 83.23 and 28.77mg/g at pH 3 and 6.5, respectively, which is superior to most ZrO2 based adsorbents reported in the literature and better than that of native PANI. Furthermore, the developed adsorbent manifested quite a selective fluoride uptake at pH 3 as compared to pH 6.5±0.1 wherein significant chemical affinity competition was presented by phosphate ions followed by bicarbonate and sulfate. The recyclability of HZrO2@PANI NFs for four cycles and its applicability to fluoride spiked ground water has also been demonstrated. The adsorption mechanism was interpreted with the help of FTIR, XPS and Zeta potential analysis and the results revealed the involvement of both anion exchange and electrostatic attraction in the adsorption of F(-) ions. Thus, a new efficient adsorbent with reasonably high adsorption capacity and superior pH tolerance has been developed for fluoride removal. Copyright © 2017 Elsevier Inc. All rights reserved.

  12. Morphological and structural investigation of wool-derived keratin nanofibres crosslinked by thermal treatment.

    Science.gov (United States)

    Aluigi, Annalisa; Corbellini, Alessandro; Rombaldoni, Fabio; Zoccola, Marina; Canetti, Maurizio

    2013-06-01

    Mats of wool-derived keratin nanofibre have been prepared by electrospinning solutions of keratin in formic acid at 20 and 15 wt.%, and obtaining nanofibres with mean diameter of about 400 and 250 nm, respectively. These mats can find applications in tissue engineering (they can mimic the native extracellular matrix) and in wastewater treatment (they can trap small particles and adsorb heavy-metals). A drawback to overcome is their solubility in water. A stabilization method, based on a thermal treatment alternative to the use of formaldehyde, is proposed. The solubility test in the dithiothreitol/urea extraction buffer, the amino acid composition analysis and studies on keratin secondary structures suggest that the improved stability in water of thermally treated mats can be ascribed to the formation of amide bonds between acid and basic groups of some amino acid side chains. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. A novel approach for the fabrication of carbon nanofibre/ceramic porous structures

    KAUST Repository

    Walter, Claudia

    2013-11-01

    This paper describes the fabrication of hybrid ceramic/carbon scaffolds in which carbon nanofibres and multi-walled carbon nanotubes fully cover the internal walls of a microporous ceramic structure that provides mechanical stability. Freeze casting is used to fabricate a porous, lamellar ceramic (Al2O3) structure with aligned pores whose width can be controlled between 10 and 90μm. Subsequently, a two step chemical vapour deposition process that uses iron as a catalyst is used to grow the carbon nanostructures inside the scaffold. This catalyst remains in the scaffold after the growth process. The formation of the alumina scaffold and the influence of its structure on the growth of nanofibres and tubes are investigated. A set of growth conditions is determined to produce a dense covering of the internal walls of the porous ceramic with the carbon nanostructures. The limiting pore size for this process is located around 25μm. © 2013 Elsevier Ltd.

  14. Silver/polysaccharide-based nanofibrous materials synthesized from green chemistry approach.

    Science.gov (United States)

    Martínez-Rodríguez, M A; Garza-Navarro, M A; Moreno-Cortez, I E; Lucio-Porto, R; González-González, V A

    2016-01-20

    In this contribution a novel green chemistry approach for the synthesis of nanofibrous materials based on blends of carboxymethyl-cellulose (CMC)-silver nanoparticles (AgNPs) composite and polyvinyl-alcohol (PVA) is proposed. These nanofibrous materials were obtained from the electrospinning of blends of aqueous solutions of CMC-AgNPs composite and PVA, which were prepared at different CMC/PVA weight ratios in order to electrospin nanofibers applying a constant tension of 15kV. The synthesized materials were characterized by means of transmission electron microscopy, scanning electron microscopy; as well as Fourier-transform infrared, ultraviolet and Raman spectroscopic techniques. Experimental evidence suggests that the diameter of the nanofibers is thinner than any other reported in the literature regarding the electrospinning of CMC. This feature is related to the interactions of AgNPs with carboxyl functional groups of the CMC, which diminish those between the later and acetyl groups of PVA.

  15. Evaluation of an air spinning process to produce tailored biosynthetic nanofibre scaffolds.

    Science.gov (United States)

    Sabbatier, Gad; Abadie, Pierre; Dieval, Florence; Durand, Bernard; Laroche, Gaétan

    2014-02-01

    We optimised the working parameters of an innovative air spinning device to produce nanofibrous polymer scaffolds for tissue engineering applications. Scanning electron microscopy was performed on the fibre scaffolds which were then used to identify various scaffold morphologies based on the ratio of surface occupied by the polymer fibres on that covered by the entire polymer scaffold assembly. Scaffolds were then produced with the spinning experimental parameters, resulting in 90% of fibres in the overall polymer construct, and were subsequently used to perform a multiple linear regression analysis to highlight the relationship between nanofibre diameter and the air spinning parameters. Polymer solution concentration was deemed as the most significant parameter to control fibre diameter during the spinning process, despite interactions between experimental parameters. Based on these findings, viscosity measurements were performed to clarify the effect of the polymer solution property on scaffold morphology.

  16. Electrohydrodynamic direct-writing of three-dimensional multi-loop nanofibrous coils

    Science.gov (United States)

    Zheng, Gaofeng; Yu, Zhaojie; Zhuang, Mingfeng; Wei, Wen; Zhao, Yang; Zheng, Jiangyi; Sun, Daoheng

    2014-07-01

    This paper studies the whipping deposition behavior of straight charged jets of Near-Field Electrospinning. A micro 3D structure of multi-loop nanofibrous coil was printed on a silicon collector. The whipping motion resulted from Coulomb force caused the charged jet to deposit and form a coiled structure. With the guidance of deposited nanofiber, the charged jet deposited layer by layer to build up a 3D nanofibrous coiled structure with 3-50 loops. The diameter of the coiled structure ranged from 4 to 60 μm. The number of loops decreased with the increase of collector motion speed, due to shorter post-deposition relaxing time. With higher stress inside the charged jet, PEO solution of higher concentration led to fewer loops but larger diameter of the coil. This work provides a promising method to study the control technology of charged jet printing, which may push forward the development of micro 3D inkjet printing technology.

  17. Hydrophilicity improvement in polyphenylsulfone nanofibrous filtration membranes through addition of polyethylene glycol

    Science.gov (United States)

    Kiani, Shirin; Mousavi, Seyed Mahmoud; Shahtahmassebi, Nasser; Saljoughi, Ehsan

    2015-12-01

    Novel hydrophilic polyphenylsulfone (PPSU) nanofibrous membrane was prepared by electrospinning of the PPSU solution blended with polyethylene glycol 400 (PEG 400). The influence of the PEG concentration on the membrane characteristics was studied using scanning electron microscopy (SEM), water contact angle measurement, and tensile test. Filtration performance of the membranes was investigated by measurement of pure water flux (PWF) and determination of the rejection values of the pollution indices during treatment of canned beans production wastewater. According to the results, blending the PPSU solution with 10 wt.% PEG 400 resulted in formation of a nanofibrous membrane with high porosity and increased mechanical strength which exhibited a low water contact angle of 8.9° and high water flux of 7920 L/m2h. Flux recovery of the mentioned membrane which was assessed by filtration of a solution containing bovine serum albumin (BSA) was 83% indicating a noticeable antifouling property.

  18. Electrospun nanofibre bundles and yarns for tissue engineering applications: A review.

    Science.gov (United States)

    O'Connor, Richard A; McGuinness, Garrett B

    2016-11-01

    Nanofibre membranes produced through the electrospinning process have been studied extensively over the past decade for a number of high demand applications including use as tissue engineered scaffolds. Despite possessing desirable properties including high surface area to volume ratios and enhanced mechanical properties, they ultimately suffer from a lack of cellular infiltration. Variations on the process include the production of highly aligned filaments of electrospun fibres referred to as bundles and yarns. Nanofibre bundle and yarn-based scaffolds have been shown to demonstrate superior cell infiltration rates compared to traditional electrospun nonwovens while also offering the capability to be incorporated into a wider array of post-processing technologies. In this review, fibre collection techniques currently employed within the literature for the fabrication of electrospun bundles and yarns along with their applications in the field of tissue engineering will be discussed.

  19. Characterisation of solution cast cellulose nanofibre – reinforced poly(lactic acid

    Directory of Open Access Journals (Sweden)

    2010-01-01

    Full Text Available Cellulose nanofibres, 20 nm in diameter and 300 nm long, were prepared by acid hydrolysis of flax yarns. Composite films containing 2.5 and 5.0 wt% flax cellulose (FC fibres were prepared by solution casting of mixtures of poly(lactic acid (PLA solution and cellulose nanofibre suspension in chloroform. The resulting composite films and solution cast pure PLA film, with thickness of around 160 m, showed good transparency. For composites with 2.5 and 5.0 wt% FC, the tensile strength increased by 25 and 59% and tensile modulus by 42 and 47%, respectively, compared to pure PLA film. The composite film with 2.5 wt% FC combined high strength and ductility with tensile strength of 24.3 MPa and 70% elongation at break. Flax cellulose appeared to facilitate nucleation and subsequent crystallisation of PLA more effectively in the amorphous composites than in the crystalline composites.

  20. Fabrication of α-chitin whisker-reinforced poly(vinyl alcohol) nanocomposite nanofibres by electrospinning

    Science.gov (United States)

    Junkasem, Jirawut; Rujiravanit, Ratana; Supaphol, Pitt

    2006-09-01

    The present contribution reports, for the first time, the successful fabrication of α-chitin whisker-reinforced poly(vinyl alcohol) (PVA) nanocomposite nanofibres by electrospinning. The α-chitin whiskers were prepared from α-chitin flakes from shrimp shells by acid hydrolysis. The as-prepared chitin whiskers exhibited lengths in the range 231-969 nm and widths in the range 12-65 nm, with the average length and width being about 549 and 31 nm, respectively. Successful incorporation of the chitin whiskers within the as-spun PVA/chitin whisker nanocomposite nanofibres was verified by infrared spectroscopic and thermogravimetric methods. The incorporation of chitin whiskers within the as-spun nanocomposite fibre mats increased the Young's modulus by about 4-8 times over that of the neat as-spun PVA fibre mat.

  1. Fabrication of {alpha}-chitin whisker-reinforced poly(vinyl alcohol) nanocomposite nanofibres by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Junkasem, Jirawut; Rujiravanit, Ratana; Supaphol, Pitt [Technological Center for Electrospun Fibers and the Petroleum and Petrochemical College, Chulalongkorn University, Soi Chula 12, Phyathai Road, Pathumwan, Bangkok 10300 (Thailand)

    2006-09-14

    The present contribution reports, for the first time, the successful fabrication of {alpha}-chitin whisker-reinforced poly(vinyl alcohol) (PVA) nanocomposite nanofibres by electrospinning. The {alpha}-chitin whiskers were prepared from {alpha}-chitin flakes from shrimp shells by acid hydrolysis. The as-prepared chitin whiskers exhibited lengths in the range 231-969 nm and widths in the range 12-65 nm, with the average length and width being about 549 and 31 nm, respectively. Successful incorporation of the chitin whiskers within the as-spun PVA/chitin whisker nanocomposite nanofibres was verified by infrared spectroscopic and thermogravimetric methods. The incorporation of chitin whiskers within the as-spun nanocomposite fibre mats increased the Young's modulus by about 4-8 times over that of the neat as-spun PVA fibre mat.

  2. A highly sensitive humidity sensor based on a nanofibrous membrane coated quartz crystal microbalance

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xianfeng; Ding Bin [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Yu Jianyong [Nanomaterials Research Center, Modern Textile Institute, Donghua University, Shanghai 200051 (China); Wang, Moran [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Pan Fukui, E-mail: binding@dhu.edu.cn [College of Textiles and Fashion, Qingdao University, Qingdao 266071 (China)

    2010-02-05

    A novel humidity sensor was fabricated by electrospinning deposition of nanofibrous polyelectrolyte membranes as sensitive coatings on a quartz crystal microbalance (QCM). The results of sensing experiments indicated that the response of the sensors increased by more than two orders of magnitude with increasing relative humidity (RH) from 6 to 95% at room temperature, exhibiting high sensitivity, and that, in the range of 20-95% RH, the Log({Delta}f) showed good linearity. The sensitivity of fibrous composite polyacrylic acid (PAA)/poly(vinyl alcohol) (PVA) membranes was two times higher than that of the corresponding flat films at 95% RH. Compared with fibrous PAA/PVA membranes, the nanofibrous PAA membranes exhibited remarkably enhanced humidity sensitivity due to their high PAA content and large specific surface area caused by the formation of ultrathin nanowebs among electrospun fibers. Additionally, the resultant sensors exhibited a good reversible behavior and good long term stability.

  3. A highly sensitive humidity sensor based on a nanofibrous membrane coated quartz crystal microbalance

    Science.gov (United States)

    Wang, Xianfeng; Ding, Bin; Yu, Jianyong; Wang, Moran; Pan, Fukui

    2010-02-01

    A novel humidity sensor was fabricated by electrospinning deposition of nanofibrous polyelectrolyte membranes as sensitive coatings on a quartz crystal microbalance (QCM). The results of sensing experiments indicated that the response of the sensors increased by more than two orders of magnitude with increasing relative humidity (RH) from 6 to 95% at room temperature, exhibiting high sensitivity, and that, in the range of 20-95% RH, the Log(Δf) showed good linearity. The sensitivity of fibrous composite polyacrylic acid (PAA)/poly(vinyl alcohol) (PVA) membranes was two times higher than that of the corresponding flat films at 95% RH. Compared with fibrous PAA/PVA membranes, the nanofibrous PAA membranes exhibited remarkably enhanced humidity sensitivity due to their high PAA content and large specific surface area caused by the formation of ultrathin nanowebs among electrospun fibers. Additionally, the resultant sensors exhibited a good reversible behavior and good long term stability.

  4. A novel porphyrin-containing polyimide nanofibrous membrane for colorimetric and fluorometric detection of pyridine vapor.

    Science.gov (United States)

    Lv, Yuanyuan; Zhang, Yani; Du, Yanglong; Xu, Jiayao; Wang, Junbo

    2013-11-19

    A novel zinc porphyrin-containing polyimide (ZPCPI) nanofibrous membrane for rapid and reversible detection of trace amounts of pyridine vapor is described. The membrane displays a distinct color change, as well as dramatic variations in absorption and fluorescent emission spectra, upon exposure to pyridine vapor. This condition allows the detection of the analyte at concentrations as low as 0.041 ppm. The vapochromic and spectrophotometric responses of the membrane are attributed to the formation of the ZPCPI-pyridine complex upon axial coordination. From surface plasmon resonance analysis, the affinity constant of ZPCPI-pyridine complex was calculated to be (3.98 ± 0.25) × 104 L · mol(-1). The ZPCPI nanofibrous membrane also showed excellent selectivity for pyridine vapor over other common amines, confirming its applicability in the manufacture of pyridine-sensitive gas sensors.

  5. Scaling Laws and Mesoscopic Modeling of Heat Transfer in Nanofibrous Materials and Composites

    Science.gov (United States)

    2013-11-26

    buckypaper, and other materials composed of carbon nanotubes (CNTs), individual CNTs are bound together by van der Waals forces and form entangled...for nanofibrous materials based on carbon nanotubes (CNTs) are investigated by performing a multiscale computational study combining atomistic...composition on the ejection and transport of polymer molecules and carbon nanotubes in matrix-assisted pulsed laser evaporation, Appl. Phys. A 105, 529

  6. The Development of Nanofibrous Media Filter Containing Nanoparticles for Removing Particles from Air Stream

    OpenAIRE

    S. Farhang Dehghan; B Maddah; F Golbabaei

    2016-01-01

    Background and Objectives: The goal of the present study was to develop nanofibrous media filters containing MgO nanoparticles for future application in removing particles from gas stream. Materials and Methods: Electrospun nanofibers were fabricated using experimental design prepared by Response Surface Methodology. Optimization of electrospinning parameters was conducted for achieving the desired filter properties including fiber diameter, porosity, and bead number. ...

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

    Science.gov (United States)

    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.

  8. Magnetic biodegradable Fe3O4/CS/PVA nanofibrous membranes for bone regeneration.

    Science.gov (United States)

    Wei, Yan; Zhang, Xuehui; Song, Yu; Han, Bing; Hu, Xiaoyang; Wang, Xinzhi; Lin, Yuanhua; Deng, Xuliang

    2011-10-01

    In recent years, interest in magnetic biomimetic scaffolds for tissue engineering has increased considerably. The aim of this study is to develop magnetic biodegradable fibrous materials with potential use in bone regeneration. Magnetic biodegradable Fe(3)O(4)/chitosan (CS)/poly vinyl alcohol (PVA) nanofibrous membranes were achieved by electrospinning with average fiber diameters ranging from 230 to 380 nm and porosity of 83.9-85.1%. The influences of polymer concentration, applied voltage and Fe(3)O(4) nanoparticles loading on the fabrication of nanofibers were investigated. The polymer concentration of 4.5 wt%, applied voltage of 20 kV and Fe(3)O(4) nanoparticles loading of lower than 5 wt% could produce homogeneous, smooth and continuous Fe(3)O(4)/CS/PVA nanofibrous membranes. X-ray diffraction (XRD) data confirmed that the crystalline structure of the Fe(3)O(4), CS and PVA were maintained during electrospinning process. Fourier transform infrared spectroscopy (FT-IR) demonstrated that the Fe(3)O(4) loading up to 5 wt% did not change the functional groups of CS/PVA greatly. Transmission electron microscopy (TEM) showed islets of Fe(3)O(4) nanoparticles evenly distributed in the fibers. Weak ferrimagnetic behaviors of membranes were revealed by vibrating sample magnetometer (VSM) test. Tensile test exhibited Young's modulus of membranes that were gradually enhanced with the increase of Fe(3)O(4) nanoparticles loading, while ultimate tensile stress and ultimate strain were slightly reduced by Fe(3)O(4) nanoparticles loading of 5%. Additionally, MG63 human osteoblast-like cells were seeded on the magnetic nanofibrous membranes to evaluate their bone biocompatibility. Cell growth dynamics according to MTT assay and scanning electron microscopy (SEM) observation exhibited good cell adhesion and proliferation, suggesting that this magnetic biodegradable Fe(3)O(4)/CS/PVA nanofibrous membranes can be one of promising biomaterials for facilitation of osteogenesis.

  9. Environmental friendly method for the extraction of coir fibre and isolation of nanofibre

    CSIR Research Space (South Africa)

    Abraham, E

    2013-02-01

    Full Text Available -1 Carbohydrate Polymers February 2013/ Vol.9 No 2 Environmental friendly method for the extraction of coir fibre and isolation of nanofibre Eldho Abraham a,b,d, B. Deepab, L.A. Pothenb,?, J. Cintilc, S. Thomasc, M.J. Johnd, R. Anandjiwala d , S....S. Narine a a Trent Biomaterials Research Program, Trent University, Peterborough, Ontario, Canada b Department of Chemistry, Bishop Moore College, Mavelikkara, Kerala, India c School of Chemical Sciences, Mahatma Gandhi University, Kottayam 686...

  10. In-situ synthesis of magnetic iron-oxide nanoparticle-nanofibre composites using electrospinning.

    Science.gov (United States)

    Burke, Luke; Mortimer, Chris J; Curtis, Daniel J; Lewis, Aled R; Williams, Rhodri; Hawkins, Karl; Maffeis, Thierry G G; Wright, Chris J

    2017-01-01

    We demonstrate a facile, one-step process to form polymer scaffolds composed of magnetic iron oxide nanoparticles (MNPs) contained within electrospun nano- and micro-fibres of two biocompatible polymers, Poly(ethylene oxide) (PEO) and Poly(vinyl pyrrolidone) (PVP). This was achieved with both needle and free-surface electrospinning systems demonstrating the scalability of the composite fibre manufacture; a 228 fold increase in fibre fabrication was observed for the free-surface system. In all cases the nanoparticle-nanofibre composite scaffolds displayed morphological properties as good as or better than those previously described and fabricated using complex multi-stage techniques. Fibres produced had an average diameter (Needle-spun: 125±18nm (PEO) and 1.58±0.28μm (PVP); Free-surface electrospun: 155±31nm (PEO)) similar to that reported previously, were smooth with no bead defects. Nanoparticle-nanofibre composites were characterised using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), dynamic light scattering (DLS) (Nanoparticle average diameter ranging from 8±3nm to 27±5nm), XRD (Phase of iron oxide nanoparticles identified as magnetite) and nuclear magnetic resonance relaxation measurements (NMR) (T1/T2: 32.44 for PEO fibres containing MNPs) were used to verify the magnetic behaviour of MNPs. This study represents a significant step forward for production rates of magnetic nanoparticle-nanofibre composite scaffolds by the electrospinning technique.

  11. Preparation and characterization of polysaccharides/PVA blend nanofibrous membranes by electrospinning method.

    Science.gov (United States)

    Santos, Carla; Silva, Carla J; Büttel, Zsófia; Guimarães, Rodrigo; Pereira, Sara B; Tamagnini, Paula; Zille, Andrea

    2014-01-01

    A series of polyvinyl alcohol (PVA), PVA/chitosan (CS) and PVA/cyanobacterial extracellular polymeric substances (EPS) blended nanofibrous membranes were produced by electrospinning using a microfiltration poly(vinylidene fluoride) (PVDF) basal membrane, for potential applications in water filtration. Nanofibres were obtained from solutions of 20% (w/w) PVA with 1% (w/w) CS or EPS, using a weight ratio of 60/40. Blended nanofibres have shown a smooth morphology, no beads formation and diameters between 50 and 130 nm. Thermo-mechanical analysis demonstrated that there were inter and/or intramolecular hydrogen bonds between the molecules of PVA/CS and PVA/EPS in the blends. The electrospun blended PVA/EPS membrane showed better tensile mechanical properties when compared with PVA and PVA/CS, and resisted more against disintegration in the temperature range between 10 and 50 °C. Finally, the blended membranes have shown an increase in chromium binding capacity of 5%. This is the first successful report of a blended membrane of electrospinned cyanobacterial polysaccharide with PVA.

  12. Doxorubicin-loaded PLA/pearl electrospun nanofibrous scaffold for drug delivery and tumor cell treatment

    Science.gov (United States)

    Dai, Jiamu; Jin, Junhong; Yang, Shenglin; Li, Guang

    2017-07-01

    A drug-loaded implantable scaffold is a promising substitute for the treatment of tissue defects after a tumor resection operation. In this work, natural pearl powder with good biocompatibility and osteoconductivity was incorporated into polylactic (PLA) nanofibers via electrospinning, and doxorubicin hydrochloride (DOX) was also loaded in the PLA/pearl scaffold, resulting in a drug-loaded composite nanofibrous scaffold (DOX@PLA/pearl). In vitro drug delivery of DOX from a PLA/pearl composite scaffold was measured and in vitro anti-tumor efficacy was also examined, in particular the effect of the pearl content on both key properties were studied. The results showed that DOX was successfully loaded into PLA/pearl composite nanofibrous scaffolds with different pearl content. More importantly, the delivery rate of DOX kept rising as the pearl content increased, and the anti-tumor efficacy of the drug-loaded scaffold on HeLa cells was improved at an appropriate pearl powder concentration. Thus, we expect that the prepared DOX@PLA/pearl powder nanofibrous mat is a highly promising implantable scaffold that has great potential in postoperative cancer treatment.

  13. Physio-chemical and antibacterial characteristics of pressure spun nylon nanofibres embedded with functional silver nanoparticles.

    Science.gov (United States)

    Xu, Z; Mahalingam, S; Rohn, J L; Ren, G; Edirisinghe, M

    2015-11-01

    A novel and facile approach to prepare hybrid nanoparticle embedded polymer nanofibers using pressurised gyration is presented. Silver nanoparticles and nylon polymer were used in this work. The polymer solution's physical properties, rotating speed and the working pressure had a significant influence on the fibre diameter and the morphology. Fibres in the range of 60-500nm were spun using 10wt.%, 15wt.% and 20wt.% nylon solutions and these bead-free fibres were processed under 0.2MPa and 0.3MPa working pressure and a rotational speed of 36,000rpm. 1-4wt.% of Ag was added to these nylon solutions and in the case of wt.% fibres in the range 50-150nm were prepared using the same conditions of pressurised gyration. Successful incorporation of the Ag nanoparticles in nylon nanofibres was confirmed by using a combination of advanced microscopical techniques and Raman spectrometry was used to study the bonding characteristics of nylon and the Ag nanoparticles. Inductively coupled plasma mass spectroscopy showed a substantial concentration of Ag ions in the nylon fibre matrix which is essential for producing effective antibacterial properties. Antibacterial activity of the Ag-loaded nanofibres shows higher efficacy than nylon nanofibres for Gram-negative Escherichia coli and Pseudomonas aeruginosa microorganisms, and both Ag nanoparticles and the Ag ions were found to be the reason for enhanced cell death in the bacterial solutions.

  14. Formation of bacterial pilus-like nanofibres by designed minimalistic self-assembling peptides

    Science.gov (United States)

    Guterman, Tom; Kornreich, Micha; Stern, Avigail; Adler-Abramovich, Lihi; Porath, Danny; Beck, Roy; Shimon, Linda J. W.; Gazit, Ehud

    2016-11-01

    Mimicking the multifunctional bacterial type IV pili (T4Ps) nanofibres provides an important avenue towards the development of new functional nanostructured biomaterials. Yet, the development of T4Ps-based applications is limited by the inability to form these nanofibres in vitro from their pilin monomers. Here, to overcome this limitation, we followed a reductionist approach and designed a self-assembling pilin-based 20-mer peptide, derived from the presumably bioelectronic pilin of Geobacter sulfurreducens. The designed 20-mer, which spans sequences from both the polymerization domain and the functionality region of the pilin, self-assembled into ordered nanofibres. Investigation of the 20-mer revealed that shorter sequences which correspond to the polymerization domain form a supramolecular β-sheet, contrary to their helical configuration in the native T4P core, due to alternative molecular recognition. In contrast, the sequence derived from the functionality region maintains a native-like, helical conformation. This study presents a new family of self-assembling peptides which form T4P-like nanostructures.

  15. Note: Non-invasive optical method for rapid determination of alignment degree of oriented nanofibrous layers

    Energy Technology Data Exchange (ETDEWEB)

    Pokorny, M.; Rebicek, J. [R& D Department, Contipro Biotech s.r.o., 561 02 Dolni Dobrouc (Czech Republic); Klemes, J. [R& D Department, Contipro Pharma a.s., 561 02 Dolni Dobrouc (Czech Republic); Kotzianova, A. [R& D Department, Contipro Pharma a.s., 561 02 Dolni Dobrouc (Czech Republic); Department of Chemistry, Faculty of Science, Masaryk University, Kamenice 5, CZ-62500 Brno (Czech Republic); Velebny, V. [R& D Department, Contipro Biotech s.r.o., 561 02 Dolni Dobrouc (Czech Republic); R& D Department, Contipro Pharma a.s., 561 02 Dolni Dobrouc (Czech Republic)

    2015-10-15

    This paper presents a rapid non-destructive method that provides information on the anisotropic internal structure of nanofibrous layers. A laser beam of a wavelength of 632.8 nm is directed at and passes through a nanofibrous layer prepared by electrostatic spinning. Information about the structural arrangement of nanofibers in the layer is directly visible in the form of a diffraction image formed on a projection screen or obtained from measured intensities of the laser beam passing through the sample which are determined by the dependency of the angle of the main direction of polarization of the laser beam on the axis of alignment of nanofibers in the sample. Both optical methods were verified on Polyvinyl alcohol (PVA) nanofibrous layers (fiber diameter of 470 nm) with random, single-axis aligned and crossed structures. The obtained results match the results of commonly used methods which apply the analysis of electron microscope images. The presented simple method not only allows samples to be analysed much more rapidly and without damaging them but it also makes possible the analysis of much larger areas, up to several square millimetres, at the same time.

  16. Polymer nanofibre junctions of attolitre volume serve as zeptomole-scale chemical reactors.

    Science.gov (United States)

    Anzenbacher, Pavel; Palacios, Manuel A

    2009-04-01

    Methods allowing chemical reactions to be carried out on ultra-small scales in a controllable fashion are potentially important for a number of disciplines, including molecular electronics, photonics and molecular biology, and may provide fundamental insight into chemistry in confined spaces. Ultra-small-scale reactions also circumvent potential problems associated with reagent and product toxicity, and reduce energy consumption and waste generation. Here, we report a technique for performing chemical reactions on a zeptomole (10(-21) mol) scale. We show that electrospun polymer nanofibres with a diameter of 100-300 nm can be loaded with reactants, and that the junctions formed between crossed nanofibres can function as attolitre-volume reactors. Exposure to heat or solvent vapours fuses the fibres and initiates the reaction. The reaction products can be analysed directly within the nanofibre junctions by fluorescence measurements and mass spectrometry, and solvent extraction of multiple reactors allows product identification by common micromethods such as high-performance liquid chromatography-mass spectrometry.

  17. Nanocomposites of silver nanoparticles embedded in glass nanofibres obtained by laser spinning.

    Science.gov (United States)

    Cabal, Belén; Quintero, Félix; Díaz, Luís Antonio; Rojo, Fernando; Dieste, Oliver; Pou, Juan; Torrecillas, Ramón; Moya, José Serafín

    2013-05-07

    Nanocomposites made of non-woven glass fibres with diameters ranging from tens of nanometers up to several micrometers, containing silver nanoparticles, were successfully fabricated by the laser spinning technique. Pellets of a soda-lime silicate glass containing silver nanoparticles with varying concentrations (5 and 10 wt%) were used as a precursor. The process followed to obtain the silver nanofibres did not agglomerate significantly the metallic nanoparticles, and the average particle size is still lower than 50 nm. This is the first time that glass nanofibres containing silver nanoparticles have been obtained following a process different from electrospinning of a sol-gel, thus avoiding the limitations of this method and opening a new route to composite nanomaterials. Antibacterial efficiency of the nanosilver glass fibres, tested against one of the most common gram negative bacteria, was greater than 99.99% compared to the glass fibres free of silver. The silver nanoparticles are well-dispersed not only on the surface but are also embedded into the uniform nanofibres, which leads to a long lasting durable antimicrobial effect. All these novel characteristics will potentially open up a whole new range of applications.

  18. Nanocomposites of silver nanoparticles embedded in glass nanofibres obtained by laser spinning

    Science.gov (United States)

    Cabal, Belén; Quintero, Félix; Díaz, Luís Antonio; Rojo, Fernando; Dieste, Oliver; Pou, Juan; Torrecillas, Ramón; Moya, José Serafín

    2013-04-01

    Nanocomposites made of non-woven glass fibres with diameters ranging from tens of nanometers up to several micrometers, containing silver nanoparticles, were successfully fabricated by the laser spinning technique. Pellets of a soda-lime silicate glass containing silver nanoparticles with varying concentrations (5 and 10 wt%) were used as a precursor. The process followed to obtain the silver nanofibres did not agglomerate significantly the metallic nanoparticles, and the average particle size is still lower than 50 nm. This is the first time that glass nanofibres containing silver nanoparticles have been obtained following a process different from electrospinning of a sol-gel, thus avoiding the limitations of this method and opening a new route to composite nanomaterials. Antibacterial efficiency of the nanosilver glass fibres, tested against one of the most common Gram negative bacteria, was greater than 99.99% compared to the glass fibres free of silver. The silver nanoparticles are well-dispersed not only on the surface but are also embedded into the uniform nanofibres, which leads to a long lasting durable antimicrobial effect. All these novel characteristics will potentially open up a whole new range of applications.

  19. Fabrication of gelatin/calcium phosphate composite nanofibrous membranes by biomimetic mineralization.

    Science.gov (United States)

    Choi, Mi Ok; Kim, Young-Jin

    2012-06-01

    Based on the principles of biomimetic mineralization, biocomposite nanofibrous membranes were fabricated by the growth of CaP crystals on electrospun gelatin nanofibers to mimic both the physical architecture and chemical composition of natural bone ECM. Plenty more CaP crystals formed on the nanofibrous membrane containing Ca(2+) ion precursors, in which these crystals were also observed on the inner side of membrane. The release rate of Ca(2+) ion precursors from the nanofibrous membrane was slower than that of PO(4)(3-) ion precursors, suggesting the existence of more strong intermolecular interaction between gelatin and Ca(2+) ions. ATR-FTIR and XRD results clearly revealed the formation of CaP crystals mixed with apatite and CaCO(3), or apatite and TCP on the membranes. The Ca/P molar ratio of crystals obtained from the XPS data was 2.03 and 1.60, which depended on the mineralization conditions. Higher amount of CaP crystals significantly accelerated the deposit rate of bone-like apatite on the surface of composite membrane, meaning to the improved in vivo bone bioactivity.

  20. Integration of nondegradable polystyrene and degradable gelatin in a core–sheath nanofibrous patch for pelvic reconstruction

    Science.gov (United States)

    Ge, Liangpeng; Li, Qingtao; Jiang, Junzi; You, Xiaoyan; Liu, Zuohua; Zhong, Wen; Huang, Yong; Xing, Malcolm MQ

    2015-01-01

    Pelvic organ prolapse (POP) is a serious health issue affecting many adult women. Complications of POP include pelvic pressure, pelvic pain, and problems in emptying their bowels or bladder. Sometimes, POP may even cause urinary outflow obstruction and lead to bladder or kidney infections. Currently, synthetic and naturally derived materials have been chosen for treatment of POP to reduce the high recurrence rates after surgical interventions. However, existing materials for POP treatment cannot meet the clinical requirements in terms of biocompatibility, mechanics, and minimal risk of rejection. Especially, erosion in synthetic polymers and rapid degradation in natural polymers limit their further applications in clinics. To address these concerns, we report a novel POP replacement using core–sheath polystyrene/gelatin electrospun nanofiber mesh. The outside gelatin sheath provides a hydrophilic surface and implantable integrity between host and guest, while the inner PS core offers the necessary mechanical support. The composite mesh shows graft accommodation in pelvic submucosa after implantation in vivo, as shown in hematoxylin–eosin staining and T helper cell phenotype and macrophage phenotype stainings. Qualitative analysis of inducible nitric oxide synthase, arginase, interferon-γ, and interleukin-10 gene expressions also indicates that the implanted composite mesh switches to accommodation mode 2 weeks postimplantation. Thus, these novel core–sheath polystyrene/gelatin nanofibrous membranes are promising in pelvic reconstruction. PMID:25995629

  1. Laccase Immobilized on a PAN/Adsorbents Composite Nanofibrous Membrane for Catechol Treatment by a Biocatalysis/Adsorption Process

    Directory of Open Access Journals (Sweden)

    Qingqing Wang

    2014-03-01

    Full Text Available The treatment of catechol via biocatalysis and adsorption with a commercial laccase immobilized on polyacrylonitrile/montmorillonite/graphene oxide (PAN/MMT/GO composite nanofibers was evaluated with a homemade nanofibrous membrane reactor. The properties in this process of the immobilized laccase on PAN, PAN/MMT as well as PAN/MMT/GO with different weight ratios of MMT and GO were investigated. These membranes were successfully applied for removal of catechol from an aqueous solution. Scanning electron microscope images revealed different morphologies of the enzyme aggregates on different supports. After incorporation of MMT or MMT/GO, the optimum pH showed an alkaline shift to 4, compared to 3.5 for laccase immobilized on pure PAN nanofibers. The optimum temperature was at 55 °C for all the immobilized enzymes. Besides, the addition of GO improved the operational stability and storage stability. A 39% ± 2.23% chemical oxygen demand (COD removal from the catechol aqueous solution was achieved. Experimental results suggested that laccase, PAN, adsorbent nanoparticles (MMT/GO can be combined together for catechol treatment in industrial applications.

  2. Highly efficient nonprecious metal catalyst prepared with metal–organic framework in a continuous carbon nanofibrous network

    Science.gov (United States)

    Shui, Jianglan; Chen, Chen; Grabstanowicz, Lauren; Zhao, Dan; Liu, Di-Jia

    2015-01-01

    Fuel cell vehicles, the only all-electric technology with a demonstrated >300 miles per fill travel range, use Pt as the electrode catalyst. The high price of Pt creates a major cost barrier for large-scale implementation of polymer electrolyte membrane fuel cells. Nonprecious metal catalysts (NPMCs) represent attractive low-cost alternatives. However, a significantly lower turnover frequency at the individual catalytic site renders the traditional carbon-supported NPMCs inadequate in reaching the desired performance afforded by Pt. Unconventional catalyst design aiming at maximizing the active site density at much improved mass and charge transports is essential for the next-generation NPMC. We report here a method of preparing highly efficient, nanofibrous NPMC for cathodic oxygen reduction reaction by electrospinning a polymer solution containing ferrous organometallics and zeolitic imidazolate framework followed by thermal activation. The catalyst offers a carbon nanonetwork architecture made of microporous nanofibers decorated by uniformly distributed high-density active sites. In a single-cell test, the membrane electrode containing such a catalyst delivered unprecedented volumetric activities of 3.3 A⋅cm−3 at 0.9 V or 450 A⋅cm−3 extrapolated at 0.8 V, representing the highest reported value in the literature. Improved fuel cell durability was also observed. PMID:26261338

  3. Integration of nondegradable polystyrene and degradable gelatin in a core-sheath nanofibrous patch for pelvic reconstruction.

    Science.gov (United States)

    Ge, Liangpeng; Li, Qingtao; Jiang, Junzi; You, Xiaoyan; Liu, Zuohua; Zhong, Wen; Huang, Yong; Xing, Malcolm M Q

    2015-01-01

    Pelvic organ prolapse (POP) is a serious health issue affecting many adult women. Complications of POP include pelvic pressure, pelvic pain, and problems in emptying their bowels or bladder. Sometimes, POP may even cause urinary outflow obstruction and lead to bladder or kidney infections. Currently, synthetic and naturally derived materials have been chosen for treatment of POP to reduce the high recurrence rates after surgical interventions. However, existing materials for POP treatment cannot meet the clinical requirements in terms of biocompatibility, mechanics, and minimal risk of rejection. Especially, erosion in synthetic polymers and rapid degradation in natural polymers limit their further applications in clinics. To address these concerns, we report a novel POP replacement using core-sheath polystyrene/gelatin electrospun nanofiber mesh. The outside gelatin sheath provides a hydrophilic surface and implantable integrity between host and guest, while the inner PS core offers the necessary mechanical support. The composite mesh shows graft accommodation in pelvic submucosa after implantation in vivo, as shown in hematoxylin-eosin staining and T helper cell phenotype and macrophage phenotype stainings. Qualitative analysis of inducible nitric oxide synthase, arginase, interferon-γ, and interleukin-10 gene expressions also indicates that the implanted composite mesh switches to accommodation mode 2 weeks postimplantation. Thus, these novel core-sheath polystyrene/gelatin nanofibrous membranes are promising in pelvic reconstruction.

  4. Laccase immobilized on a PAN/adsorbents composite nanofibrous membrane for catechol treatment by a biocatalysis/adsorption process.

    Science.gov (United States)

    Wang, Qingqing; Cui, Jing; Li, Guohui; Zhang, Jinning; Li, Dawei; Huang, Fenglin; Wei, Qufu

    2014-03-19

    The treatment of catechol via biocatalysis and adsorption with a commercial laccase immobilized on polyacrylonitrile/montmorillonite/graphene oxide (PAN/MMT/GO) composite nanofibers was evaluated with a homemade nanofibrous membrane reactor. The properties in this process of the immobilized laccase on PAN, PAN/MMT as well as PAN/MMT/GO with different weight ratios of MMT and GO were investigated. These membranes were successfully applied for removal of catechol from an aqueous solution. Scanning electron microscope images revealed different morphologies of the enzyme aggregates on different supports. After incorporation of MMT or MMT/GO, the optimum pH showed an alkaline shift to 4, compared to 3.5 for laccase immobilized on pure PAN nanofibers. The optimum temperature was at 55 °C for all the immobilized enzymes. Besides, the addition of GO improved the operational stability and storage stability. A 39% ± 2.23% chemical oxygen demand (COD) removal from the catechol aqueous solution was achieved. Experimental results suggested that laccase, PAN, adsorbent nanoparticles (MMT/GO) can be combined together for catechol treatment in industrial applications.

  5. Fabrication and hemocompatibility assessment of novel polyurethane-based bio-nanofibrous dressing loaded with honey and Carica papaya extract for the management of burn injuries

    Science.gov (United States)

    Balaji, Arunpandian; Jaganathan, Saravana Kumar; Ismail, Ahmad Fauzi; Rajasekar, Rathanasamy

    2016-01-01

    Management of burn injury is an onerous clinical task since it requires continuous monitoring and extensive usage of specialized facilities. Despite rapid improvizations and investments in burn management, >30% of victims hospitalized each year face severe morbidity and mortality. Excessive loss of body fluids, accumulation of exudate, and the development of septic shock are reported to be the main reasons for morbidity in burn victims. To assist burn wound management, a novel polyurethane (PU)-based bio-nanofibrous dressing loaded with honey (HN) and Carica papaya (PA) fruit extract was fabricated using a one-step electrospinning technique. The developed dressing material had a mean fiber diameter of 190±19.93 nm with pore sizes of 4–50 µm to support effective infiltration of nutrients and gas exchange. The successful blending of HN- and PA-based active biomolecules in PU was inferred through changes in surface chemistry. The blend subsequently increased the wettability (14%) and surface energy (24%) of the novel dressing. Ultimately, the presence of hydrophilic biomolecules and high porosity enhanced the water absorption ability of the PU-HN-PA nanofiber samples to 761.67% from 285.13% in PU. Furthermore, the ability of the bio-nanofibrous dressing to support specific protein adsorption (45%), delay thrombus formation, and reduce hemolysis demonstrated its nontoxic and compatible nature with the host tissues. In summary, the excellent physicochemical and hemocompatible properties of the developed PU-HN-PA dressing exhibit its potential in reducing the clinical complications associated with the treatment of burn injuries. PMID:27621626

  6. Offshore Substrate

    Data.gov (United States)

    California Department of Resources — This shapefile displays the distribution of substrate types from Pt. Arena to Pt. Sal in central/northern California. Originally this data consisted of seven paper...

  7. In situ deposition of a personalized nanofibrous dressing via a handy electrospinning device for skin wound care

    Science.gov (United States)

    Dong, Rui-Hua; Jia, Yue-Xiao; Qin, Chong-Chong; Zhan, Lu; Yan, Xu; Cui, Lin; Zhou, Yu; Jiang, Xingyu; Long, Yun-Ze

    2016-02-01

    Current strategies for wound care provide limited relief to millions of patients who suffer from burns, chronic skin ulcers or surgical-related wounds. The goal of this work is to develop an in situ deposition of a personalized nanofibrous dressing via a handy electrospinning (e-spinning) device and evaluate its properties related to skin wound care. MCM-41 type mesoporous silica nanoparticles decorated with silver nanoparticles (Ag-MSNs) were prepared by a facile and environmentally friendly approach, which possessed long-term antibacterial activity and low cytotoxicity. Poly-ε-caprolactone (PCL) incorporated with Ag-MSNs was successfully electrospun (e-spun) into nanofibrous membranes. These in situ e-spun nanofibrous membranes allowed the continuous release of Ag ions and showed broad-spectrum antimicrobial activity against two common types of pathogens, Staphylococcus aureus and Escherichia coli. In addition, the in vivo studies revealed that these antibacterial nanofibrous membranes could reduce the inflammatory response and accelerate wound healing in Wistar rats. The above results strongly demonstrate that such patient-specific dressings could be broadly applied in emergency medical transport, hospitals, clinics and at the patients' home in the near future.Current strategies for wound care provide limited relief to millions of patients who suffer from burns, chronic skin ulcers or surgical-related wounds. The goal of this work is to develop an in situ deposition of a personalized nanofibrous dressing via a handy electrospinning (e-spinning) device and evaluate its properties related to skin wound care. MCM-41 type mesoporous silica nanoparticles decorated with silver nanoparticles (Ag-MSNs) were prepared by a facile and environmentally friendly approach, which possessed long-term antibacterial activity and low cytotoxicity. Poly-ε-caprolactone (PCL) incorporated with Ag-MSNs was successfully electrospun (e-spun) into nanofibrous membranes. These in situ e

  8. NiMoO{sub 4} nanofibres designed by electrospining technique for glucose electrocatalytic oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Sheng-Hui; Lu, Shi-Yu; Bao, Shu-Juan, E-mail: baoshj@swu.edu.cn; Yu, Ya-Nan; Wang, Min-Qiang

    2016-01-28

    Electrochemical oxidation of glucose is the guarantee to realize nonenzymatic sensing of glucose, but greatly hindered by the slow kinetics of its oxidation process. Herein, various nanomaterials were designed as catalysts to accelerate glucose oxidation reaction. However, how to effectively build an excellent platform for promoting the glucose oxidation is still a great challenge. In our work, 1D CaMoO{sub 4} and NiMoO{sub 4} nanofibres with same morphologies and sub-microstructures were fabricated by electrospinning technique in the first time, and explored to modify the detection electrodes of nonenzymatic glucose sensors. The electrochemical results indicated that the NiMoO{sub 4} based sensor exhibited a good catalytic activity toward glucose including the low response potential (0.5 V), high sensitivity(193.8 μA mM{sup −1} cm{sup −2}) with a linear response region of 0.01–8 mM, low detection limit (4.6 μM) and fast response time (2 s), all of which are superior to the corresponding values of CaMoO{sub 4} nanofibres and even higher than those of most reported NiO and Co{sub 3}O{sub 4} catalysts, which is due to the NiMoO{sub 4} nanofibres are not only advantageous to electron transfer, but can mediated the electrocatalytic reaction of glucose. This work should provide a new pathway for the design of advanced glucose catalysts for nonenzymatic sensor. - Graphical abstract: Electrocatalytic reaction of NiMoO{sub 4} based non-enzymatic glucose sensor. - Highlights: • 1D NiMoO{sub 4} nanofibres were fabricated by electrospinning technique in the first time. • 1D NiMoO{sub 4} nanofibres were applied in nonenzymatic glucose sensors firstly. • A possible electrocatalytic mechanism of the nanoparticles for the glucose oxidation was proposed. • This work holds great promise for development advanced glucose catalysts for nonenzymatic sensor.

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

    Energy Technology Data Exchange (ETDEWEB)

    Skotak, Maciej [Biomechanics, Biomaterials and Biomedicine Instrumentation Facility, College of Engineering, University of Nebraska-Lincoln, NE 68588-0642 (United States); Ragusa, Jorge; Gonzalez, Daniela; Subramanian, Anuradha, E-mail: asubramanian2@unl.edu [Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, NE 68588-0643 (United States)

    2011-10-15

    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 {mu}m, as estimated with mercury intrusion porosimetry. Non-templated gelatin-based nanofibrous matrices had an average pore size of 1 {mu}m. Fibroblasts were seeded onto both types of the gelatin-based nanofibrous surfaces and cultured for 14 days. For comparative purposes, chitosan-based and polyurethane-based macroporous scaffolds with pore sizes of 100 and 170 {mu}m, respectively, were also 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 and 90 {mu}m 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 easily be extended toward other classes of electrospun polymer matrices for tissue engineering.

  10. Polyvinylidene fluoride/siloxane nanofibrous membranes for long-term continuous CO2 -capture with large absorption-flux enhancement.

    Science.gov (United States)

    Lin, Yi-Feng; Wang, Chi-Sen; Ko, Chia-Chieh; Chen, Chien-Hua; Chang, Kai-Shiun; Tung, Kuo-Lun; Lee, Kueir-Rarn

    2014-02-01

    In a CO2 membrane contactor system, CO2 passes through a hydrophobic porous membrane in the gas phase to contact the amine absorbent in the liquid phase. Consequently, additional CO2 gas is absorbed by amine absorbents. This study examines highly porous polyvinylidene fluoride (PVDF)/siloxane nanofibrous layers that are modified with hydrophobic fluoroalkylsilane (FAS) functional groups and successfully coated onto a macroporous Al2 O3 membrane. The performance of these materials in a membrane contactor system for CO2 absorption is also investigated. Compared with pristine PVDF nanofibrous membranes, the PVDF/siloxane nanofibrous membranes exhibit greater solvent resistance and mechanical strength, making them more suitable for use in CO2 capture by the membrane contactor. The PVDF/siloxane nanofibrous layer in highly porous FAS-modified membranes can prevent the wetting of the membrane by the amine absorbent; this extends the periods of continuous CO2 absorption and results in a high CO2 absorption flux with a minimum of 500 % enhancement over that of the uncoated membranes. This study suggests the potential use of an FAS-modified PVDF/siloxane nanofibrous membrane in a membrane contactor system for CO2 absorption. The resulting hydrophobic membrane contactor also demonstrates the potential for large-scale CO2 absorption during post-combustion processes in power plants.

  11. Facile Fabrication of ZnO/TiO2 Heterogeneous Nanofibres and Their Photocatalytic Behaviour and Mechanism towards Rhodamine B

    Directory of Open Access Journals (Sweden)

    JiaDong Chen

    2016-02-01

    Full Text Available In this study, novel titanium dioxide (TiO2 and zinc oxide (ZnO hybrid photocatalysts in the form of nanofibres were fabricated by a facile method using electrospinning followed by a calcination process. Scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD and X-ray photoelectron spectroscopy (XPS were employed to investigate the morphology and structure of the heterogeneous nanofi‐ bres. The photocatalytic performances were evaluated via the photodegradation of Rhodamine B (RhB under irradiation with UV light. Due to the low recombination rate of photo-induced charge carriers, the high utilization efficiency of UV light and the large contact area with the target molecules, the ZnO/TiO2 hybrid nanofibres exhibit‐ ed high catalytic activity towards the Rhodamine B, and the amount of Zn(OAc2 in the precursor of these nanofibres played an important role in determining the photo decom‐ position performance.

  12. Hydrothermal in situ preparation of TiO2 particles onto poly(lactic acid) electrospun nanofibres

    Science.gov (United States)

    Gupta, Kamal K.; Mishra, Pradeep K.; Srivastava, Pradeep; Gangwar, Mayank; Nath, Gopal; Maiti, Pralay

    2013-01-01

    The novel poly(lactic acid) (PLA)/TiO2 hybrid nanofibres are produced via electrospinning technique. Hydrolysed titanium precursor has been electrosprayed simultaneously on the continuous electrospun PLA nanofibres surface. The adhered amorphous titania has been transformed into TiO2 particle through hydrothermal treatment for different times. The phase structure has been worked out using XRD, FTIR, XPS and Raman spectroscopy. The predominant phase is anatase with a small extent of brookite phase after the hydrothermal treatment. The size and location of TiO2 particle have been determined using SEM micrographs. The orderness of the PLA crystallites has been checked using XRD patterns before and after hydrothermal treatment. UV absorption capability of the titania coated nanofibres has been enhanced to a significant level. The antimicrobial activity of the hybrids has been verified using two different microorganisms (gram negative Escherichia coli and gram positive Staphylococcus aureus bacteria) and 70% reduction of antimicrobial activity has been reported.

  13. Liquid-liquid electro-organo-synthetic processes in a carbon nanofibre membrane microreactor: Triple phase boundary effects in the absence of intentionally added electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Watkins, John D.; Ahn, Sunyhik D.; Taylor, James E.; Bull, Steven D. [Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom); Bulman-Page, Philip C. [School of Chemistry, University of East Anglia, Norwich, Norfolk NR4 7TJ (United Kingdom); Marken, Frank, E-mail: F.Marken@bath.ac.uk [Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY (United Kingdom)

    2011-07-30

    Graphical abstract: Display Omitted Highlights: > Amphiphilic carbon nanofiber membrane employed in electro-synthesis. > Triple phase boundary process within a carbon membrane. > Electrochemical deuteration in a liquid|liquid micro-reactor system. > Triple phase boundary reaction zone effects in electro-synthesis. - Abstract: An amphiphilic carbon nanofibre membrane electrode (ca. 50 nm fibre diameter, 50-100 {mu}m membrane thickness) is employed as an active working electrode and separator between an aqueous electrolyte phase (with reference and counter electrode) and an immiscible organic acetonitrile phase (containing only the redox active material). Potential control is achieved with a reference and counter electrode located in the aqueous electrolyte phase, but the electrolysis is conducted in the organic acetonitrile phase in the absence of intentionally added supporting electrolyte. For the one-electron oxidation of n-butylferrocene coupled to perchlorate anion transfer from aqueous to organic phase effective electrolysis is demonstrated with an apparent mass transfer coefficient of m = 4 x 10{sup -5} m s{sup -1} and electrolysis of typically 1 mg n-butylferrocene in a 100 {mu}L volume. For the two-electron reduction of tetraethyl-ethylenetetracarboxylate the apparent mass transfer coefficient m = 4 x 10{sup -6} m s{sup -1} is lower due to a less extended triple phase boundary reaction zone in the carbon nanofibre membrane. Nevertheless, effective electrolysis of up to 6 mg tetraethyl-ethylenetetracarboxylate in a 100 {mu}L volume is demonstrated. Deuterated products are formed in the presence of D{sub 2}O electrolyte media. The triple phase boundary dominated mechanism and future microreactor design improvements are discussed.

  14. Anti-fogging nanofibrous SiO(2) and nanostructured SiO(2)-TiO(2) films made by rapid flame deposition and in situ annealing.

    Science.gov (United States)

    Tricoli, Antonio; Righettoni, Marco; Pratsinis, Sotiris E

    2009-11-03

    Transparent, pure SiO(2), TiO(2), and mixed silica-titania films were (stochastically) deposited directly onto glass substrates by flame spray pyrolysis of organometallic solutions (hexamethyldisiloxane or tetraethyl orthosilicate and/or titanium tetra isopropoxide in xylene) and stabilized by in situ flame annealing. Silicon dioxide films consisted of a network of interwoven nanofibers or nanowires several hundred nm long and 10-15 nm thick, as determined by microscopy. These nanowire or nanofibrous films were formed by chemical vapor deposition (surface growth) on bare glass substrates during scalable combustion of precursor solutions at ambient conditions, for the first time to our knowledge, as determined by thermophoretic sampling of the flame aerosol and microscopy. In contrast, titanium dioxide films consisted of nanoparticles 3-5 nm in diameter that were formed in the flame and deposited onto the glass substrate, resulting in highly porous, lace-like nanostructures. Mixed SiO(2)-TiO(2) films (40 mol % SiO(2)) had similar morphology to pure TiO(2) films. Under normal solar radiation, all such films having a minimal thickness of about 300 nm completely prevented fogging of the glass substrates. These anti-fogging properties were attributed to inhibition of water droplet formation by such super-hydrophilic coatings as determined by wetting angle measurements. Deactivated (without UV radiation) pure TiO(2) coatings lost their super-hydrophilicity and anti-fogging properties even though their wetting angle was reduced by their nanowicking. In contrast, SiO(2)-TiO(2) coatings exhibited the best anti-fogging performance at all conditions taking advantage of the high surface coverage by TiO(2) nanoparticles and the super-hydrophilic properties of SiO(2) on their surface.

  15. Nanofibre Electrospinning Poly(vinyl alcohol and Cellulose Composite Mats Obtained by Use of a Cylindrical Electrode

    Directory of Open Access Journals (Sweden)

    Anna Sutka

    2013-01-01

    Full Text Available A study of nanofibre composites obtained by electrospinning from poly(vinyl alcohol (PVA solutions of steam exploded hemp fibres and shives is reported. A combined treatment of steam explosion (SE, ball milling, and high-intensity ultrasound (HIUS is applied to prepare cellulose nanofibres (CNF from hemp fibres (CNF-F and shives (CNF-S. The reflectance Fourier transform infrared (FTIR ATR spectroscopy is used to analyze the obtained PVA/CNF composite mats. Morphology of the PVA/CNF composites was studied by scanning electron microscopy (SEM.

  16. Phylum Level Change in the Cecal and Fecal Gut Communities of Rats Fed Diets Containing Different Fermentable Substrates Supports a Role for Nitrogen as a Factor Contributing to Community Structure

    Directory of Open Access Journals (Sweden)

    Martin Kalmokoff

    2015-05-01

    Full Text Available Fermentation differs between the proximal and distal gut but little is known regarding how the bacterial communities differ or how they are influenced by diet. In order to investigate this, we compared community diversity in the cecum and feces of rats by 16S rRNA gene content and DNA shot gun metagenomics after feeding purified diets containing different fermentable substrates. Gut community composition was dependent on the source of fermentable substrate included in the diet. Cecal communities were dominated by Firmicutes, and contained a higher abundance of Lachnospiraceae compared to feces. In feces, community structure was shifted by varying degrees depending on diet towards the Bacteroidetes, although this change was not always evident from 16S rRNA gene data. Multi-dimensional scaling analysis (PCoA comparing cecal and fecal metagenomes grouped by location within the gut rather than by diet, suggesting that factors in addition to substrate were important for community change in the distal gut. Differentially abundant genes in each environment supported this shift away from the Firmicutes in the cecum (e.g., motility towards the Bacteroidetes in feces (e.g., Bacteroidales transposons. We suggest that this phylum level change reflects a shift to ammonia as the primary source of nitrogen used to support continued microbial growth in the distal gut.

  17. Fabrication and characterization of bactericidal thiol-chitosan and chitosan iodoacetamide nanofibres.

    Science.gov (United States)

    Abdelgawad, Abdelrahman M; El-Naggar, Mehrez E; Hudson, Samuel M; Rojas, Orlando J

    2017-01-01

    Two chitosan derivatives, namely, thiol-chitosan (TCs) and chitosan iodoacetamide (CsIA) were newly synthesized by reacting Cs with thiglycolic acid (TGA) and iodoacetic acid (IA) respectively. After being crosslinked with glutraldehyde (GA), the two derivatives were submitted to FT-IR and H(1) NMR analysis for identification and characterization of their chemical features. As TCs and CsIA are water soluble, their electrospun nanofibres mats from aqueous solutions could be crosslinked and achieved using polyvinyl alcohol/Chitosan blend (PVA/Cs) polymers. Morphological structures of the obtained nanofibres and their webs were studied via those of TCs and CsIA free systems. The data also indicate that the crosslinked PVA/Cs/CsIA is more thermally stable than the crosslinked PVA/Cs/TCs and crosslinked PVA/Cs respectively. It was proved that the electrospun fibers containing TCs or CsIA display a superior antibacterial activity against negative bacteria E. Coli with a minimum inhibitory concentration (MIC) of 400μg/ml. These effects are rather in confirmation with bacterial kinetics essays which were also carried out in current work. Of particular interest is that the antimicrobial properties of fibers containing small concentration of either TCs or CsIA are much superior than those obtained with neat Cs electrospun nanofibres used as reference. By and large the results advocate the fibers webs containing TCs or CsIA as excellent candidates for wound dressing applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Electrospun doping of carbon nanotubes and platinum nanoparticles into the β-phase polyvinylidene difluoride nanofibrous membrane for biosensor and catalysis applications.

    Science.gov (United States)

    Zhang, Panpan; Zhao, Xinne; Zhang, Xuan; Lai, Yue; Wang, Xinting; Li, Jingfeng; Wei, Gang; Su, Zhiqiang

    2014-05-28

    A novel β-phase polyvinylidene difluoride (PVDF) nanofibrous membrane decorated with multiwalled carbon nanotubes (MWCNTs) and platinum nanoparticles (PtNPs) was fabricated by an improved electrospinning technique. The morphology of the fabricated PVDF-MWCNT-PtNP nanofibrous membrane was observed by scanning electron microscopy, and the formation of high β-phase in the hybrid nanofibrous membrane was investigated by Fourier transform infrared spectroscopy and differential scanning calorimetry. The uniform dispersion of MWCNTs and PtNPs in the PVDF hybrid nanofibrous membrane and their interaction were explored by transmission electron microscopy and X-ray diffraction. For the first time, we utilized this created PVDF-MWCNT-PtNP nanofibrous membrane for biosensor and catalysis applications. The nonenzymatic amperometric biosensor with highly stable and sensitive, and selective detection of both H2O2 and glucose was successfully fabricated based on the electrospun PVDF-MWCNT-PtNP nanofibrous membrane. In addition, the catalysis of the hybrid nanofibrous membrane for oxygen reduction reaction was tested, and a good catalysis performance was found. We anticipate that the strategies utilized in this work will not only guide the further design of functional nanofiber-based biomaterials and biodevices but also extend the potential applications in energy storage, cytology, and tissue engineering.

  19. A biocompatibility study of new nanofibrous scaffolds for nervous system regeneration

    Science.gov (United States)

    Raspa, A.; Marchini, A.; Pugliese, R.; Mauri, M.; Maleki, M.; Vasita, R.; Gelain, F.

    2015-12-01

    effective therapy will require contribution of different disciplines such as materials science, cell biology, drug delivery and nanotechnology. One of the biggest challenges in SCI regeneration is to create an artificial scaffold that could mimic the extracellular matrix (ECM) and support nervous system regeneration. Electrospun constructs and hydrogels based on self-assembling peptides (SAPs) have been recently preferred. In this work SAPs and polymers were assembled by using a coaxial electrospinning setup. We tested the biocompatibility of two types of coaxially electrospun microchannels: the first one made by a core of poly(ε-caprolactone) and poly(d,l-lactide-co-glycolide) (PCL-PLGA) and a shell of an emulsion of PCL-PLGA and a functionalized self-assembling peptide Ac-FAQ and the second one made by a core of Ac-FAQ and a shell of PCL-PLGA. Moreover, we tested an annealed scaffold by PCL-PLGA microchannel heat-treatment. The properties of coaxial scaffolds were analyzed using scanning electron microscopy (SEM), Fourier transform spectroscopy (FTIR), contact angle measurements and differential scanning calorimetry (DSC). In vitro cytotoxicity was assessed via viability and differentiation assays with neural stem cells (NSCs); whereas in vivo inflammatory response was evaluated following scaffold implantation in rodent spinal cords. Emulsification of the outer shell turned out to be the best choice in terms of cell viability and tissue response: thus suggesting the potential of using functionalized SAPs in coaxial electrospinning for applications in regenerative medicine. Electronic supplementary information (ESI) available: In vivo analysis to evaluate tissue reaction in the scaffold implant walls (Fig. S1) and to test axonal regeneration (Fig. S2). Waters LC-MS Alliance-3100 analysis to confirm the molecular weight and the integrity of peptides following the electrospray process (Fig. S3). Water contact angle of electrospun nanofibrous mats (Fig. S4). See DOI: 10

  20. Magnetoelectric CoFe2O4/polyvinylidene fluoride electrospun nanofibres

    Science.gov (United States)

    Gonçalves, R.; Martins, P.; Moya, X.; Ghidini, M.; Sencadas, V.; Botelho, G.; Mathur, N. D.; Lanceros-Mendez, S.

    2015-04-01

    Magnetoelectric 0-1 composites comprising CoFe2O4 (CFO) nanoparticles in a polyvinylidene fluoride (PVDF) polymer-fibre matrix have been prepared by electrospinning. The average diameter of the electrospun composite fibres is ~325 nm, independent of the nanoparticle content, and the amount of the crystalline polar β phase is strongly enhanced when compared to pure PVDF polymer fibres. The piezoelectric response of these electroactive nanofibres is modified by an applied magnetic field, thus evidencing the magnetoelectric character of the CFO/PVDF 0-1 composites.

  1. Highly Efficient Coupling of Nanolight Emitters to a Ultra-wide Tunable Nanofibre Cavity

    CERN Document Server

    Schell, Andreas W; Kamioka, Shunya; Oe, Yasuko; Fujiwara, Masazumi; Benson, Oliver; Takeuchi, Shigeki

    2015-01-01

    Solid-state microcavities combining ultra-small mode volume, wide-range resonance frequency tuning, as well as lossless coupling to a single mode fibre are integral tools for nanophotonics and quantum networks. We developed an integrated system providing all of these three indispensable properties. It consists of a nanofibre Bragg cavity (NFBC) with the mode volume of under 1 micro cubic meter and repeatable tuning capability over more than 20 nm at visible wavelengths. In order to demonstrate quantum light-matter interaction, we establish coupling of quantum dots to our tunable NFBC and achieve an emission enhancement by a factor of 2.7.

  2. Aerosynthesis: Growth of Vertically-aligned Carbon Nanofibres with Air DC Plasma

    Directory of Open Access Journals (Sweden)

    A. Kodumagulla

    2014-03-01

    Full Text Available Vertically-aligned carbon nanofibres (VACNFs have been synthesized in a mixture of acetone and air using catalytic DC plasma-enhanced chemical vapour deposition. Typically, ammonia or hydrogen is used as an etchant gas in the mixture to remove carbon that otherwise passivates the catalyst surface and impedes growth. Our demonstration of the use of air as the etchant gas opens up the possibility that ion etching could be sufficient to maintain the catalytic activity state during synthesis. It also demonstrates a path toward growing VACNFs in the open atmosphere.

  3. Thermal carbonization of nanoporous silicon: Formation of carbon nanofibres without a metal catalyst

    Indian Academy of Sciences (India)

    Gunjan Aggarwal; Prabhash Mishra; Bipin Joshi; S S Islam

    2014-09-01

    An interesting phenomenon is observed while carrying out thermal carbonization of porous silicon (PS) with an aim to arrest the natural surface degradation, and it is a burning issue for PS-based device applications. A tubular carbon structure has been observed on the PS surface. Raman, Fourier transform infrared spectroscopy (FTIR) and electron microscope studies, revealed that the tubular structure is nothing but amorphous carbon nanofibres sprouted within the pores in the absence of a metal catalyst, for which a suitable explanation is proposed.

  4. Preparation of CuS nanoparticles embedded in poly(vinyl alcohol) nanofibre via electrospinning

    Indian Academy of Sciences (India)

    Jia Xu; Xuejun Cui; Jinhui Zhang; Hongwei Liang; Hongyan Wang; Junfeng Li

    2008-04-01

    Poly(vinyl alcohol) (PVA)/CuS composite nanofibres were successfully prepared by electrospinning technique and gas–solid reaction. Scanning electron microscopic (SEM) images showed that the average diameter of PVA/CuS fibres was about 150–200 nm. Transmission electron microscopy (TEM) proved that a majority of CuS nanoparticles with an average diameter of about 15–25 nm are incorporated in the PVA fibres. Xray diffraction (XRD) analyses and electron diffraction pattern also revealed the forming of CuS crystal structure in the PVA fibres.

  5. Engineering of fiber-reinforced tissues with anisotropic biodegradable nanofibrous scaffolds.

    Science.gov (United States)

    Nerurkar, Nandan L; Baker, Brendon M; Chen, Chiu-Yu; Elliott, Dawn M; Mauck, Robert L

    2006-01-01

    The repair of dense fiber-reinforced tissues poses a significant challenge for the tissue engineering community. The function of these structures is largely dependent on their architectural form, and as such, scaffold organization is an important design parameter in generating tissue analogues. To address this issue, we have recently utilized electrospinning to instill controllable fiber anisotropy in nanofibrous scaffolds. This abstract details the mechanical characterization of the bulk and local properties of these scaffolds, and points to their potential application in the repair and/or generation of fiber-reinforced tissues that recapitulate the native form.

  6. In Vitro Assessment of Antibacterial Activity and Cytocompatibility of Quercetin-Containing PLGA Nanofibrous Scaffolds for Tissue Engineering

    Directory of Open Access Journals (Sweden)

    Zhi-Cai Xing

    2012-01-01

    Full Text Available Flavonoids, such as quercetin, have been reported to exhibit a wide range of biological activities related to their antioxidant capacity. The aim of this study was to investigate the protective effect of quercetin on cell adhesion, and the viability and proliferation of KB epithelial cells. Quercetin- (1, 5 wt%-containing poly (l-lactide-co-glycolide (PLGA nanofibrous scaffolds (PLGA/Q 1, PLGA/Q 5 were prepared by electrospinning technique and their antibacterial properties were examined. Two types of bacteria strains, Staphylococcus aureus (SA and Klebsiella pneumoniae (KP, were used to evaluate the antibacterial properties of the scaffolds. The results showed that the quercetin-containing PLGA nanofibrous scaffolds exhibited significant antibacterial effects against the two bacterial strains. KB epithelial cells were also used to evaluate the cytocompatibility of the scaffolds. From the results, it was found that the PLGA nanofibrous scaffolds with 1 wt% of quercetin had good cell compatibility. It is considered that the PLGA nanofibrous scaffolds with 1 wt% quercetin have potential to be used in tissue engineering.

  7. Novel, silver-ion-releasing nanofibrous scaffolds exhibit excellent antibacterial efficacy without the use of silver nanoparticles.

    Science.gov (United States)

    Mohiti-Asli, Mahsa; Pourdeyhimi, Behnam; Loboa, Elizabeth G

    2014-05-01

    Nanofibers, with their morphological similarities to the extracellular matrix of skin, hold great potential for skin tissue engineering. Over the last decade, silver nanoparticles have been extensively investigated in wound-healing applications for their ability to provide antimicrobial benefits to nanofibrous scaffolds. However, the use of silver nanoparticles has raised concerns as these particles can penetrate into the stratum corneum of skin, or even diffuse into the cellular plasma membrane. We present and evaluate a new silver ion release polymeric coating that we have found can be applied to biocompatible, biodegradable poly(l-lactic acid) nanofibrous scaffolds. Using this compound, custom antimicrobial silver-ion-releasing nanofibers were created. The presence of a uniform, continuous silver coating on the nanofibrous scaffolds was verified by XPS analysis. The antimicrobial efficacy of the antimicrobial scaffolds against Staphylococcus aureus and Escherichia coli bacteria was determined via industry-standard AATCC protocols. Cytotoxicity analyses of the antimicrobial scaffolds toward human epidermal keratinocytes and human dermal fibroblasts were performed via quantitative analyses of cell viability and proliferation. Our results indicated that the custom antimicrobial scaffolds exhibited excellent antimicrobial properties while also maintaining human skin cell viability and proliferation for silver ion concentrations below 62.5μgml(-1) within the coating solution. This is the first study to show that silver ions can be effectively delivered with nanofibrous scaffolds without the use of silver nanoparticles.

  8. Enhanced Critical Size Defect Repair in Rabbit Mandible by Electrospun Gelatin/β-TCP Composite Nanofibrous Membranes

    Directory of Open Access Journals (Sweden)

    Mingming Xu

    2015-01-01

    Full Text Available The design and fabrication of biodegradable barrier membranes with satisfactory structure and composition remain a considerable challenge for periodontal tissue regeneration. We have developed a biomimetic nanofibrous membrane made from a composite of gelatin and β-tricalcium phosphate (β-TCP. We previously confirmed the in vitro biological performance of the membrane material, but the efficacy of the membranes in promoting bone repair in situ has not yet been examined. Gelatin/β-TCP composite nanofibers were fabricated by incorporation of 20 wt.% β-TCP nanoparticles into electrospun gelatin nanofibers. Electron microscopy showed that the composite membranes presented a nonwoven structure with an interconnected porous network and had a rough surface due to the β-TCP nanoparticles, which were distributed widely and uniformly throughout the gelatin-fiber matrix. The repair efficacy of rabbit mandible defects implanted with bone substitute (Bio-Oss and covered with the gelatin/β-TCP composite nanofibrous membrane was evaluated in comparison with pure gelatin nanofibrous membrane. Gross observation, histological examination, and immunohistochemical analysis showed that new bone formation and defect closure were significantly enhanced by the composite membranes compared to the pure gelatin ones. From these results, we conclude that nanofibrous gelatin/β-TCP composite membranes could serve as effective barrier membranes for guided tissue regeneration.

  9. Targeted concurrent and sequential delivery of chemotherapeutic and antiangiogenic agents to the brain by using drug-loaded nanofibrous membranes

    Science.gov (United States)

    Tseng, Yuan-Yun; Yang, Tao-Chieh; Wang, Yi-Chuan; Lee, Wei-Hwa; Chang, Tzu-Min; Kau, Yi-Chuan; Liu, Shih-Jung

    2017-01-01

    Glioblastoma is the most frequent and devastating primary brain tumor. Surgery followed by radiotherapy with concomitant and adjuvant chemotherapy is the standard of care for patients with glioblastoma. Chemotherapy is ineffective, because of the low therapeutic levels of pharmaceuticals in tumor tissues and the well-known tumor-cell resistance to chemotherapy. Therefore, we developed bilayered poly(d,l)-lactide-co-glycolide nanofibrous membranes that enabled the sequential and sustained release of chemotherapeutic and antiangiogenic agents by employing an electrospinning technique. The release characteristics of embedded drugs were determined by employing an in vitro elution technique and high-performance liquid chromatography. The experimental results showed that the fabricated nanofibers showed a sequential drug-eluting behavior, with the release of high drug levels of chemotherapeutic carmustine, irinotecan, and cisplatin from day 3, followed by the release of high concentrations of the antiangiogenic combretastatin from day 21. Biodegradable multidrug-eluting nanofibrous membranes were then dispersed into the cerebral cavity of rats by craniectomy, and the in vivo release characteristics of the pharmaceuticals from the membranes were investigated. The results suggested that the nanofibrous membranes released high concentrations of pharmaceuticals for more than 8 weeks in the cerebral parenchyma of rats. The result of histological analysis demonstrated developmental atrophy of brains with no inflammation. Biodegradable nanofibrous membranes can be manufactured for long-term sequential transport of different chemotherapeutic and anti-angiogenic agents in the brain, which can potentially improve the treatment of glioblastoma multiforme and prevent toxic effects due to systemic administration.

  10. Antimicrobial Efficacy and Cell Adhesion Inhibition of In Situ Synthesized ZnO Nanoparticles/Polyvinyl Alcohol Nanofibrous Membranes

    Directory of Open Access Journals (Sweden)

    Jian Li

    2016-01-01

    Full Text Available Nanoparticle metal oxides are emerging as a new class of important materials in medical, agricultural, and industrial applications. In this context, free zinc oxide (ZnO nanoparticles (NPs have been increasingly shown with broad antimicrobial activities. However, biological properties of immobilized ZnO NPs on matrixes like nanofibrous membranes are still limited. In this study, in situ synthesized ZnO NPs/polyvinyl alcohol (PVA nanofibrous membranes were fabricated by electrospinning with different zinc acetate concentrations. Characterization results indicated that, with 5 mM zinc acetate, uniform size ZnO NPs (~40 nm were formed and evenly distributed on the membrane surface. The surfaces became more hydrophobic with higher concentration of zinc acetate. ZnO NPs/PVA nanofibrous membranes showed a broad spectrum of antimicrobial activities and cell adhesion inhibiting effects against four microorganisms including Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli, fungi Candida albicans, and spores of Aspergillus niger. Our data revealed that the major antimicrobial mechanism could be attributed to cell membrane damage and cellular internalization of ZnO NPs, while the hydrophobic surface of the membrane primarily contributed to the cell adhesion inhibition. This study suggests that ZnO NPs/PVA nanofibrous membranes could potentially be used as an effective antimicrobial agent to maintain agricultural and food safety.

  11. Chitosan-cross-linked nanofibrous PHBV nerve guide for rat sciatic nerve regeneration across a defect bridge.

    Science.gov (United States)

    Biazar, Esmaeil; Keshel, Saeed Heidari

    2013-01-01

    The aim of this study was to produce a chitosan-cross-linked nanofibrous biodegradable poly (3-hydroxybutyrate-co-3-hydroxyvalerate) nerve conduit. The artificial nerve scaffold designed by electrospinning method and cross-linked with chitosan by chemical method. Afterwards, the scaffolds were evaluated by microscopic, physical, and mechanical analyses and cell culture assays with Schwann cells. The conduits were implanted into a 10 mm gap in the sciatic nerves of the rats. Four months after surgery, the regenerated nerves were evaluated by macroscopic assessments and histology. This polymeric conduit had sufficiently good mechanical properties to serve as a nerve guide. Cellular experiments showed a better cell adhesion, growth, and proliferation inside the cross-linked nanofibrous scaffolds compared with un-cross-linked ones, also Schwann cells well attached on chitosan-cross-linked nanofibrous surface. The in vivo results demonstrated that in the nanofibrous graft, the sciatic nerve trunk had been reconstructed with restoration of nerve continuity and formatted nerve fibers with myelination. This neural conduit appears to have the right organization for testing in vivo nerve tissue engineering studies.

  12. A novel gravity-driven nanofibrous membrane for point-of-use water disinfection: polydopamine-induced in situ silver incorporation.

    Science.gov (United States)

    Wang, Jianqiang; Wu, Yichao; Yang, Zhe; Guo, Hao; Cao, Bin; Tang, Chuyang Y

    2017-05-24

    We report a facile method for preparing silver-loaded membranes for point-of-use disinfection and disaster relief applications. A bio-inspired material, polydopamine, was coated onto a highly porous nanofibrous polyacrylonitrile substrate. We then take advantage of the redox properties of polydopamine to form silver nanoparticles in situ. These nanoparticles were uniformly distributed on the surface of nanofibers with no apparent agglomeration at a silver loading up to 4.36 wt.% (cPAN-Ag1.5). The silver-incorporated membrane cPAN-Ag1.5 achieved a high pure water flux of 130 Lm(-2) h(-1) at 10-cm water head, demonstrating the feasibility of energy-efficient gravity-driven filtration and eliminating the need for electrical power. The strong anti-bacterial activity and high physical rejection of the membrane led to an excellent disinfection power, with no viable bacterial cells detected in its permeate water. The membrane exhibited >7 log reduction for E. coli and >6 log reduction for B. subtilis. The strategy reported here provides an efficient and green route to synthesize point-of-use membranes. Combining their excellent permeability and disinfection effectiveness, these membranes offer an ideal solution to water supply in disaster-affected areas.

  13. Kevlar based nanofibrous particles as robust, effective and recyclable absorbents for water purification.

    Science.gov (United States)

    Nie, Chuanxiong; Peng, Zihang; Yang, Ye; Cheng, Chong; Ma, Lang; Zhao, Changsheng

    2016-11-15

    Developing robust and recyclable absorbents for water purification is of great demand to control water pollution and to provide sustainable water resources. Herein, for the first time, we reported the fabrication of Kevlar nanofiber (KNF) based composite particles for water purification. Both the KNF and KNF-carbon nanotube composite particles can be produced in large-scale by automatic injection of casting solution into ethanol. The resulted nanofibrous particles showed high adsorption capacities towards various pollutants, including metal ions, phenylic compounds and various dyes. Meanwhile, the adsorption process towards dyes was found to fit well with the pseudo-second-order model, while the adsorption speed was controlled by intraparticle diffusion. Furthermore, the adsorption capacities of the nanofibrous particles could be easily recovered by washing with ethanol. In general, the KNF based particles integrate the advantages of easy production, robust and effective adsorption performances, as well as good recyclability, which can be used as robust absorbents to remove toxic molecules and forward the application of absorbents in water purification.

  14. Gelation mechanism of cellulose nanofibre gels: A colloids and interfacial perspective.

    Science.gov (United States)

    Mendoza, Llyza; Batchelor, Warren; Tabor, Rico F; Garnier, Gil

    2017-09-01

    Nanocellulose gels form a new category of sustainable soft materials of industrial interest for a wide range of applications. There is a need to map the rheological properties and understand the mechanism which provides the colloidal stability and gelation of these nanofibre suspensions. TEMPO (2,2,6,6,-tetramethylpiperidine-1-oxyl)-oxidised cellulose nanofibre gels were investigated at different fibre concentrations, pH and ionic strength. Dynamic and cyclic rheological studies was performed to quantify gel behaviour and properties. Gels were produced at different pH and salt contents to map and understand colloidal stability of the nanocellulose gel. Rheology indicates gelation asa transitionary state starting at a fibre concentration of 0.1wt.%. The colloidal stability of the nanocellulose gel network is controlled by pH and salt, whereas fibre concentration mainly dictates the dynamic rheological properties. Decreasing pH and adding salt destabilises the gel network by eluting bound water which is correlated with the decrease in electrostatic repulsion between fibres. The gelation and colloidal stability of these nanocellulose gels is driven by electrostatic forces and the entanglement ability of the fibrous system to overlap. Crown Copyright © 2017. Published by Elsevier Inc. All rights reserved.

  15. Recent progress concerning the production of controlled highly oriented electrospun nanofibrous arrays

    Science.gov (United States)

    Manea, L. R.; Hristian, L.; Leon, A. L.; Popa, A.

    2016-08-01

    Among the foreground domains of all the research-development programs at national and international level, a special place is occupied by that concerning the nanosciences, nanotechnologies, new materials and technologies. Electrospinning found a well-deserved place in this space, offering the preparation of nanomaterials with distinctive properties and applications in medicine, environment, photonic sensors, filters, etc. These multiple applications are generated by the fact that the electrospinning technology makes available the production of nanofibers with controllable characteristics (length, porosity, density, and mechanical characteristics), complexity and architecture. The apparition of 3D printing technology favors the production of complex nanofibrous structures, controlled assembly, self-assembly of electrospun nanofibers for the production of scaffolds used in various medical applications. The architecture of fibrous deposits has a special influence on the subsequent development of the cells of the reconstructed organism. The present work proposes to study of recent progress concerning the production of controlled highly oriented electrospun nanofibrous arrays and progress in research on the production of complex 2D and 3D structures.

  16. Gel polymer electrolytes based on nanofibrous polyacrylonitrile–acrylate for lithium batteries

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dul-Sun [Department of Chemical and Biological Engineering, Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Woo, Jang Chang [Department of Textile Engineering, Inha University, 100 Inharo, Nam-gu Incheon 402-751 (Korea, Republic of); Youk, Ji Ho, E-mail: youk@inha.ac.kr [Department of Textile Engineering, Inha University, 100 Inharo, Nam-gu Incheon 402-751 (Korea, Republic of); Manuel, James [Department of Chemical and Biological Engineering, Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Ahn, Jou-Hyeon, E-mail: jhahn@gnu.ac.kr [Department of Chemical and Biological Engineering, Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of); Department of Materials Engineering and Convergence Technology, Gyeongsang National University, 900 Gajwa-dong, Jinju 660-701 (Korea, Republic of)

    2014-10-15

    Graphical abstract: - Highlights: • Nanofibrous polyacrylonitrile–acrylate membranes were prepared by electrospinning. • Trimethylolpropane triacrylate was used as a crosslinking agent of fibers. • The GPE based on PAN–acrylate (1/0.5) showed good electrochemical properties. - Abstract: Nanofibrous membranes for gel polymer electrolytes (GPEs) were prepared by electrospinning a mixture of polyacrylonitrile (PAN) and trimethylolpropane triacrylate (TMPTA) at weight ratios of 1/0.5 and 1/1. TMPTA is used to achieve crosslinking of fibers thereby improving mechanical strength. The average fiber diameters increased with increasing TMPTA concentration and the mechanical strength was also improved due to the enhanced crosslinking of fibers. GPEs based on electrospun membranes were prepared by soaking them in a liquid electrolyte of 1 M LiPF{sub 6} in ethylene carbonate (EC)/dimethyl carbonate (DMC) (1:1, v/v). The electrolyte uptake and ionic conductivity of GPEs based on PAN and PAN–acrylate (weight ratio; 1/1 and 1/0.5) were investigated. Ionic conductivity of GPEs based on PAN–acrylate was the highest for PAN/acrylate (1/0.5) due to the proper swelling of fibers and good affinity with liquid electrolyte. Both GPEs based on PAN and PAN–acrylate membranes show good oxidation stability, >5.0 V vs. Li/Li{sup +}. Cells with GPEs based on PAN–acrylate (1/0.5) showed remarkable cycle performance with high initial discharge capacity and low capacity fading.

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

    Science.gov (United States)

    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.

  18. LiCl-induced improvement of multilayer nanofibrous lipase for biodiesel synthesis.

    Science.gov (United States)

    Liu, Chun-Xia; Zhang, Song-Ping; Su, Zhi-Guo; Wang, Ping

    2012-01-01

    A unique method that applied a multilayer-immobilization strategy was developed to prepare nanofibrous enzymes for biosynthesis. LiCl co-electrospun with polyurethane nanofibers enabled strong physical adsorption of bovine serum albumin (BSA), forming the first layer of protein on the nanofibers; lipase AK was subsequently crosslinked to BSA as an outer layer of enzyme. The content of LiCl in nanofibers was found to be a sensitive factor affecting the activity and stability of the immobilized lipase. For biodiesel synthesis from soybean oil and methanol in isooctane, the reaction rate catalyzed by nanofibrious lipase carrying 5 wt% LiCl was 6.6-fold higher than fibers without LiCl, with a conversion of 91% was achieved within 2 h. LiCl also induced much improved enzyme stability. The nanofibrous lipase with 5% LiCl could be repeatedly used for 42 cycles without apparent activity loss, while the immobilized lipase without LiCl lost over 90% activity within 13 reuse cycles.

  19. Laminin-modified and aligned PHBV/PEO nanofibrous nerve conduits promote peripheral nerve regeneration.

    Science.gov (United States)

    Zhang, Xiao-Feng; Liu, Hai-Xia; Ortiz, Lazarus Santiago; Xiao, Zhong-Dang; Huang, Ning-Ping

    2016-11-12

    Poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) has received much attention for its biodegradability and biocompatibility, characteristics which are required in tissue engineering. In this study, polyethylene oxide (PEO)-incorporated PHBV nanofibers with random or aligned orientation were obtained by electrospinning. For further use in vivo, the nanofiber films were made into nerve conduits after treated with NH3 plasma, which could improve the hydrophilicity of inner surfaces of nerve conduits and then facilitate laminin adsorption via electrostatic interaction for promoting cell adhesion and proliferation. Morphology of the surfaces of modified PHBV/PEO nanofibrous scaffolds were examined by scanning electron microscopy. Schwann cell viability assay was conducted and the results confirmed that the functionalized nanofibers were favorable for cell growth. Morphology of Schwann cells cultured on scaffolds showed that aligned nanofibrous scaffolds provided topographical guidance for cell orientation and elongation. Furthermore, 3D PHBV/PEO nerve conduits made from aligned and random-oriented nanofibers were implanted into 12-mm transected sciatic nerve rat model and subsequent analysis were conducted at 1 and 2 months post-surgery. The above functionalized PHBV/PEO scaffolds provide a novel and promising platform for peripheral nerve regeneration.

  20. Concurrent Chemotherapy of Malignant Glioma in Rats by Using Multidrug-Loaded Biodegradable Nanofibrous Membranes

    Science.gov (United States)

    Tseng, Yuan-Yun; Huang, Yin-Chen; Yang, Tao-Chieh; Yang, Shun-Tai; Liu, Shou-Cheng; Chang, Tzu-Min; Kau, Yi-Chuan; Liu, Shih-Jung

    2016-07-01

    Glioblastoma multiforme has a poor prognosis and is highly chemoresistant. In this study, we implanted biodegradable 1,3-bis[2-chloroethyl]-1-nitroso-urea-, irinotecan-, and cisplatin-eluting poly[(d,l)-lactide-co-glycolide] (BIC/PLGA) and virgin nanofibrous membranes on the brain surface of C6 glioma-bearing rats in concurrent and virgin groups, respectively. The concentrations of all applied drugs were significantly higher in the brain than in the blood for more than 8 weeks in all studied rats. Tumor growth was more rapid in the vehicle-treated group, and tumor volumes were significantly higher in the vehicle-treated group. Moreover, the average survival time was significantly shorter in the vehicle-treated group (P = 0.026), and the BIC/PLGA nanofibrous membranes significantly reduced the risk of mortality (P < 0.001). Furthermore, the results suggested that the BIC/PLGA nanofibers reduced the malignancy of C6 glioma. The experimental findings indicate that the multianticancer drug (i.e., BIC)-eluting PLGA nanofibers are favorable candidates for treating malignant glioma.

  1. A Novel Nanohybrid Nanofibrous Adsorbent for Water Purification from Dye Pollutants

    Directory of Open Access Journals (Sweden)

    Shahin Homaeigohar

    2016-10-01

    Full Text Available In this study, we devised a novel nanofibrous adsorbent made of polyethersulfone (PES for removal of methylene blue (MB dye pollutant from water. The polymer shows a low isoelectric point thus at elevated pHs and, being nanofibrous, can offer a huge highly hydroxylated surface area for adsorption of cationic MB molecules. As an extra challenge, to augment the adsorbent’s properties in terms of adsorption capacity in neutral and acidic conditions and thermal stability, vanadium pentoxide (V2O5 nanoparticles were added to the nanofibers. Adsorption data were analyzed according to the Freundlich adsorption model. The thermodynamic parameters verified that only at basic pH is the adsorption spontaneous and in general the process is entropy-driven and endothermic. The kinetics of the adsorption process was evaluated by the pseudo-first- and pseudo-second-order models. The latter model exhibited the highest correlation with data. In sum, the adsorbent showed a promising potential for dye removal from industrial dyeing wastewater systems, especially when envisaging their alkaline and hot conditions.

  2. Fabrication of a super-hydrophobic nanofibrous zinc oxide film surface by electrospinning

    Energy Technology Data Exchange (ETDEWEB)

    Ding Bin [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); Fiber and Polymer Science, University of California, Davis, CA 95616 (United States)], E-mail: bding@ucdavis.edu; Ogawa, Tasuku [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); Kim, Jinho [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); SNT Ltd, Kawasaki 212-0054 (Japan); Fujimoto, Kouji [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); Shiratori, Seimei [Faculty of Science and Technology, Keio University, Yokohama 223-8522 (Japan); SNT Ltd, Kawasaki 212-0054 (Japan)], E-mail: shiratori@appi.keio.ac.jp

    2008-03-03

    We report a new approach for fabricating a super-hydrophobic nanofibrous zinc oxide (ZnO) film surface. The pure poly(vinyl alcohol) (PVA) and composite PVA/ZnO nanofibrous films can be obtained by electrospinning the PVA and PVA/zinc acetate solutions, respectively. After the calcination of composite fibrous films, the inorganic fibrous ZnO films with a reduced fiber diameter were fabricated. The wettability of three kinds of fibrous film surfaces were modified with a simple coating of fluoroalkylsilane (FAS) in hexane. The resultant samples were characterized by field emission scanning electron microscopy (FE-SEM), water contact angle (WCA), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). It was found that the pure PVA fibrous films maintained the super-hydrophilic surface property even after the FAS modification. Additionally, the WCA of composite fibrous films was increased from 105 to 132 deg. with the coating of FAS. Furthermore, the surface property of inorganic ZnO fibrous films was converted from super-hydrophilic (WCA of 0 deg.) to super-hydrophobic (WCA of 165{sup o}) after the surface modification with FAS. Observed from XPS data, the hydrophobicity of FAS coated various film surfaces were found to be strongly affected by the ratio of fluoro:oxygen on the film surfaces.

  3. Engineering the mechanical and biological properties of nanofibrous vascular grafts for in situ vascular tissue engineering.

    Science.gov (United States)

    Henry, Jeffrey J D; Yu, Jian; Wang, Aijun; Lee, Randall; Fang, Jun; Li, Song

    2017-08-17

    Synthetic small diameter vascular grafts have a high failure rate, and endothelialization is critical for preventing thrombosis and graft occlusion. A promising approach is in situ tissue engineering, whereby an acellular scaffold is implanted and provides stimulatory cues to guide the in situ remodeling into a functional blood vessel. An ideal scaffold should have sufficient binding sites for biomolecule immobilization and a mechanical property similar to native tissue. Here we developed a novel method to blend low molecular weight (LMW) elastic polymer during electrospinning process to increase conjugation sites and to improve the mechanical property of vascular grafts. LMW elastic polymer improved the elasticity of the scaffolds, and significantly increased the amount of heparin conjugated to the micro/nanofibrous scaffolds, which in turn increased the loading capacity of vascular endothelial growth factor (VEGF) and prolonged the release of VEGF. Vascular grafts were implanted into the carotid artery of rats to evaluate the in vivo performance. VEGF treatment significantly enhanced endothelium formation and the overall patency of vascular grafts. Heparin coating also increased cell infiltration into the electrospun grafts, thus increasing the production of collagen and elastin within the graft wall. This work demonstrates that LMW elastic polymer blending is an approach to engineer the mechanical and biological property of micro/nanofibrous vascular grafts for in situ vascular tissue engineering.

  4. Novel Self-Assembly-Induced Gelation for Nanofibrous Collagen/Hydroxyapatite Composite Microspheres

    Directory of Open Access Journals (Sweden)

    Jae-Won Choi

    2017-09-01

    Full Text Available This study demonstrates the utility of the newly developed self-assembly-induced gelation technique for the synthesis of porous collagen/hydroxyapatite (HA composite microspheres with a nanofibrous structure. This new approach can produce microspheres of a uniform size using the droplets that form at the nozzle tip before gelation. These microspheres can have a highly nanofibrous structure due to the immersion of the droplets in a coagulation bath (water/acetone, in which the collagen aggregates in the solution can self-assemble into fibrils due to pH-dependent precipitation. Bioactive HA particles were incorporated into the collagen solutions, in order to enhance the bioactivity of the composite microspheres. The composite microspheres exhibited a well-defined spherical morphology and a uniform size for all levels of HA content (0 wt %, 10 wt %, 15 wt %, and 20 wt %. Collagen nanofibers—several tens of nanometers in size—were uniformly present throughout the microspheres and the HA particles were also well dispersed. The in vitro apatite-forming ability, assessed using the simulated body fluid (SBF solution, increased significantly with the incorporation of HA into the composite microspheres.

  5. Mineralized polycaprolactone nanofibrous matrix for odontogenesis of human dental pulp cells.

    Science.gov (United States)

    Kim, Jong-Jin; Bae, Won-Jung; Kim, Joung-Mok; Kim, Jung-Ju; Lee, Eun-Jung; Kim, Hae-Won; Kim, Eun-Cheol

    2014-03-01

    The aim of the present study was to fabricate mineralized polycaprolactone nanofibrous scaffold and investigate its ability to elicit odontogenic differentiation of human dental pulp cells, compared to the pure polycaprolactone scaffold. Polycaprolactone nanofibrous scaffold was produced by electrospinning, and the surface was mineralized with apatite. Cellular behaviors on the mineralized polycaprolactone scaffold were assessed in terms of cell adhesion, growth, and odontoblastic differentiation. To evaluate the signal transduction of human dental pulp cells, mRNA expression was analyzed and Western blotting was performed. Mineralized polycaprolactone showed improved cell proliferation, mineralized nodule formation, and expression of odontoblastic marker genes including alkaline phosphatase, osteopontin, osteocalcin, dentin sialophosphoprotein (DSPP), and dentin matrix protein-1, as compared with pure polycaprolactone. Although the cell adhesion on the mineralized polycaprolactone was similar to that of the polycaprolactone, the expression level of proteins including collagen type I and the key adhesion receptor (integrin components α1, α2, and β1) was upregulated in mineralized polycaprolactone compared to polycaprolactone. Especially, cells seeded onto mineralized polycaprolactone scaffolds showed significantly increased levels of phosphorylated focal adhesion kinase, a marker of integrin activation, and downstream pathways, such as phosphor (p)-Akt, p-extracellular signal regulated kinase, p-c Jun N-terminal kinase, nuclear factor-kappa B, c-fos, and c-jun, compared with pure polycaprolactone. The mineralized polycaprolactone scaffold is attractive for dentin tissue engineering by promoting growth and odontogenic differentiation of human dental pulp cells through the integrin-mediated signaling pathway.

  6. Oxygen-plasma-modified biomimetic nanofibrous scaffolds for enhanced compatibility of cardiovascular implants

    Directory of Open Access Journals (Sweden)

    Anna Maria Pappa

    2015-01-01

    Full Text Available Electrospun nanofibrous scaffolds have been extensively used in several biomedical applications for tissue engineering due to their morphological resemblance to the extracellular matrix (ECM. Especially, there is a need for the cardiovascular implants to exhibit a nanostructured surface that mimics the native endothelium in order to promote endothelialization and to reduce the complications of thrombosis and implant failure. Thus, we herein fabricated poly-ε-caprolactone (PCL electrospun nanofibrous scaffolds, to serve as coatings for cardiovascular implants and guide tissue regeneration. Oxygen plasma treatment was applied in order to modify the surface chemistry of the scaffold and its effect on cell attachment and growth was evaluated. The conditions of the surface modification were properly adjusted in order to define those conditions of the treatment that result in surfaces favorable for cell growth, while maintaining morphological integrity and mechanical behavior. Goniometry (contact angle measurements, scanning electron microscopy (SEM, atomic force microscopy (AFM, and X-ray photoelectron spectroscopy (XPS measurements were used to evaluate the morphological and chemical changes induced by the plasma treatment. Moreover, depth-sensing nanoindentation was performed to study the resistance of the plasma-treated scaffolds to plastic deformation. Lastly, the cell studies indicated that all scaffolds were cytocompatible, with the plasma-treated ones expressing a more pronounced cell viability and adhesion. All the above findings demonstrate the great potential of these biomimetic tissue-engineering constructs as efficient coatings for enhanced compatibility of cardiovascular implants.

  7. An Advanced Electrospinning Method of Fabricating Nanofibrous Patterned Architectures with Controlled Deposition and Desired Alignment

    Science.gov (United States)

    Rasel, Sheikh Md

    We introduce a versatile advanced method of electrospinning for fabricating various kinds of nanofibrous patterns along with desired alignment, controlled amount of deposition and locally variable density into the architectures. In this method, we employed multiple electrodes whose potentials have been altered in milliseconds with the help of microprocessor based control system. Therefore, key success of this method was that the electrical field as well as charge carrying fibers could be switched shortly from one electrode's location to another, as a result, electrospun fibers could be deposited on the designated areas with desired alignment. A wide range of nanofibrous patterned architectures were constructed using proper arrangement of multiple electrodes. By controlling the concurrent activation time of two adjacent electrodes, we demonstrated that amount of fibers going into the pattern can be adjusted and desired alignment in electrospun fibers can be obtained. We also revealed that the deposition density of electrospun fibers in different areas of patterned architectures can be varied. We showed that by controlling the deposition time between two adjacent electrodes, a number of functionally graded patterns can be generated with uniaxial alignment. We also demonstrated that this handy method was capable of producing random, aligned, and multidirectional nanofibrous mats by engaging a number of electrodes and switching them in desired patterns. A comprehensive study using finite element method was carried out to understand the effects of electrical field. Simulation results revealed that electrical field strength alters shortly based on electrode control switch patterns. Nanofibrous polyvinyl alcohol (PVA) scaffolds and its composite reinforced with wollastonite and wood flour were fabricated using rotating drum electrospinning technique. Morphological, mechanical, and thermal, properties were characterized on PVA/wollastonite and PVA/wood flour nanocomposites

  8. Polydopamine-mediated surface functionalization of electrospun nanofibrous membranes: Preparation, characterization and their adsorption properties towards heavy metal ions

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Chunlin [School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003 (China); Wang, Heyun [School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003 (China); Key Laboratory for Green Processing of Chemical Engineering of Xinjiang bingtuan, Shihezi University, Shihezi 832003 (China); Wei, Zhong, E-mail: steven_weiz@sina.com [School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003 (China); Key Laboratory for Green Processing of Chemical Engineering of Xinjiang bingtuan, Shihezi University, Shihezi 832003 (China); Li, Chuan; Luo, Zhidong [School of Chemistry and Chemical Engineering, Shihezi University, Shihezi 832003 (China)

    2015-08-15

    Graphical abstract: - Highlights: • A simple and versatile approach to produce PEI-functionalized nanofibers. • Novel PEI-functionalized PVC nanofibrous membrane was prepared. • Adsorption of PVC@PDA and PVC@PDA-PEI nanofibrous membranes for Cu{sup 2+} was tested. • Isotherms, kinetic model and thermodynamic parameters were investigated. • Adsorption mechanism of Cu{sup 2+} on modified membranes was inferred. - Abstract: In this paper, a simple and versatile approach for the fabrication of a polyethyleneimine (PEI)-functionalized nanofibrous membrane utilizing polydopamine (PDA) as a mediator is proposed. The morphology and structure of the PDA-coated and PEI-grafted nanofibrous membranes were confirmed using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Due to a large specific surface area and long fibrous morphology, the synthesized membranes were used as novel adsorbents for copper ion (Cu{sup 2+}) removal from aqueous solutions. The adsorption of Cu{sup 2+} was investigated on the synthesized membranes regarding the membrane dosages, initial solution pH values, initial solution concentrations, contact times and temperatures. In addition, the adsorption equilibrium data of PEI-grafted membranes were well fitted with the Langmuir adsorption isotherm, and a maximum adsorption capacity value of 33.59 mg g{sup −1} was determined (while it was 21.94 mg g{sup −1} for the PDA-coated membranes). The thermodynamic parameters indicated that Cu{sup 2+} absorption was a spontaneous and exothermic adsorption process. In addition, XPS peak differentiation imitating analysis permitted the proposal of a copper-amine coordination adsorption mechanism that can be used to explain changes in the adsorption properties compared to PDA coating nanofibrous membranes.

  9. Deformation behavior of Re alloyed Mo thin films on flexible substrates: In situ fragmentation analysis supported by first-principles calculations.

    Science.gov (United States)

    Jörg, Tanja; Music, Denis; Hauser, Filipe; Cordill, Megan J; Franz, Robert; Köstenbauer, Harald; Winkler, Jörg; Schneider, Jochen M; Mitterer, Christian

    2017-08-07

    A major obstacle in the utilization of Mo thin films in flexible electronics is their brittle fracture behavior. Within this study, alloying with Re is explored as a potential strategy to improve the resistance to fracture. The sputter-deposited Mo1-xRex films (with 0 ≤ x ≤ 0.31) were characterized in terms of structural and mechanical properties, residual stresses as well as electrical resistivity. Their deformation behavior was assessed by straining 50 nm thin films on polyimide substrates in uniaxial tension, while monitoring crack initiation and propagation in situ by optical microscopy and electrical resistance measurements. A significant toughness enhancement occurs with increasing Re content for all body-centered cubic solid solution films (x ≤ 0.23). However, at higher Re concentrations (x > 0.23) the positive effect of Re is inhibited due to the formation of dual-phase films with the additional close packed A15 Mo3Re phase. The mechanisms responsible for the observed toughness behavior are discussed based on experimental observations and electronic structure calculations. Re gives rise to both increased plasticity and bond strengthening in these Mo-Re solid solutions.

  10. Silk fibroin/gelatin electrospun nanofibrous dressing functionalized with astragaloside IV induces healing and anti-scar effects on burn wound.

    Science.gov (United States)

    Shan, Ying-Hui; Peng, Li-Hua; Liu, Xin; Chen, Xi; Xiong, Jie; Gao, Jian-Qing

    2015-02-20

    Functional wound dressing has provided new challenges for researchers who focus on burn to improve skin graft quality, reduce scarring, and develop a pluristratified dermal or epidermal construct of a burn wound. This study aimed to investigate the effect of a silk fibroin/gelatin (SF/GT) electrospun nanofibrous dressing loaded with astragaloside IV (AS) on deep partial-thickness burn wound. AS-loaded SF/GT-blended nanofibrous dressing was prepared by electrospinning nanotechnology. The optimal ratio (25:75) of silk fibroin to gelatin was further optimized by evaluating ATR-FTIR characteristics, mechanical properties, porosity, swelling rate, degradation, and release profile of the AS-loaded SF/GT nanofibrous dressing. In contrast to the blank control, the AS-loaded SF/GT nanofibrous dressing promoted cell adhesion and proliferation with good biocompatibility in vitro (pscar formation in vivo by stimulating wound closure (ptypes of collagen, and improving collagen organization. These results showed that SF/GT nanofibrous dressing is a promising topical drug delivery system. Furthermore, AS-functionalized SF/GT nanofibrous dressing is an excellent topical therapeutic that could be applied to promote healing and elicit anti-scar effects on partial-thickness burn wound.

  11. Understanding RuO{sub 2}.xH{sub 2}O/carbon nanofibre composites as supercapacitor electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Pico, F.; Rojas, R.M.; Amarilla, J.M.; Rojo, J.M. [Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Cientificas (CSIC), Cantoblanco, Sor Juana Ines de la Cruz 3, E-28049 Madrid (Spain); Ibanez, J. [Centro Nacional de Investigaciones Metalurgicas, CSIC, Avda Gregorio del Amo 8, E-28040 Madrid (Spain); Lillo-Rodenas, M.A.; Linares-Solano, A. [MCMA, Departamento de Quimica Inorganica, Universidad de Alicante, P.O. Box 99, E-03080 Alicante (Spain)

    2008-01-21

    Composites made from RuO{sub 2}.xH{sub 2}O particles supported on carbon nanofibres (CNF) have been prepared for supercapacitor electrodes. CNF, produced by Grupo Antolin Ing. SA. using a floating catalyst procedure was treated either in HCl or in HNO{sub 3}. Then the composites were obtained by impregnation of CNF with an aqueous RuCl{sub 3}.0.5H{sub 2}O solution followed by filtering and alkali solution treatment. Heat treatment at 150 C for 2 h was done. Specific capacitance of the composites has been measured and discussed on the basis of their RuO{sub 2}.xH{sub 2}O content and RuO{sub 2}.xH{sub 2}O particle size. The composites having RuO{sub 2}.xH{sub 2}O contents below 11 wt% show RuO{sub 2}.xH{sub 2}O particles, which grow from 2 to 4 nm as the RuO{sub 2}.xH{sub 2}O content increases. The specific capacitance of supported RuO{sub 2}.xH{sub 2}O, which can be very high (up to 840 F g{sup -1}), decreases as the RuO{sub 2}.xH{sub 2}O content increases and RuO{sub 2}.xH{sub 2}O particles grow. The composites having RuO{sub 2}.xH{sub 2}O contents above 11 wt% show RuO{sub 2}.xH{sub 2}O particles of nearly constant size (4 nm); the effect of increasing the RuO{sub 2}.xH{sub 2}O content is to increase the amount of particles but not the size of the particles. In these composites the specific capacitance of supported RuO{sub 2}.xH{sub 2}O is nearly constant (440 F g{sup -1}) and close to bare RuO{sub 2}.xH{sub 2}O (460 F g{sup -1}). (author)

  12. Fabrication and hemocompatibility assessment of novel polyurethane-based bio-nanofibrous dressing loaded with honey and Carica papaya extract for the management of burn injuries

    Directory of Open Access Journals (Sweden)

    Balaji A

    2016-09-01

    Full Text Available Arunpandian Balaji,1 Saravana Kumar Jaganathan,2–4 Ahmad Fauzi Ismail,5 Rathanasamy Rajasekar6 1Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Johor Bahru, Malaysia; 2Department for Management of Science and Technology Development, Ton Duc Thang University, Ho Chi Minh City, Vietnam; 3Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam; 4IJNUTM Cardiovascular Engineering Centre, Department of Clinical Sciences, Faculty of Biosciences and Medical Engineering, Universiti Teknologi Malaysia, Johor Bahru, Malaysia; 5Advanced Membrane Technology Research Center, Universiti Teknologi Malaysia, Johor Bahru, Malaysia; 6Department of Mechanical Engineering, School of Building and Mechanical Sciences, Kongu Engineering College, Tamil Nadu, India Abstract: Management of burn injury is an onerous clinical task since it requires continuous monitoring and extensive usage of specialized facilities. Despite rapid improvizations and investments in burn management, >30% of victims hospitalized each year face severe morbidity and mortality. Excessive loss of body fluids, accumulation of exudate, and the development of septic shock are reported to be the main reasons for morbidity in burn victims. To assist burn wound management, a novel polyurethane (PU-based bio-nanofibrous dressing loaded with honey (HN and Carica papaya (PA fruit extract was fabricated using a one-step electrospinning technique. The developed dressing material had a mean fiber diameter of 190±19.93 nm with pore sizes of 4–50 µm to support effective infiltration of nutrients and gas exchange. The successful blending of HN- and PA-based active biomolecules in PU was inferred through changes in surface chemistry. The blend subsequently increased the wettability (14% and surface energy (24% of the novel dressing. Ultimately, the presence of hydrophilic biomolecules and high porosity enhanced the water absorption ability of the PU

  13. Application of chitosan/polyacrylamide nanofibres for removal of chromate and phosphate in water

    Science.gov (United States)

    Nthumbi, Richard M.; Catherine Ngila, J.; Moodley, Brenda; Kindness, Andrew; Petrik, Leslie

    Water pollution is an intractable environmental problem in South Africa. Management of the water resource is vital in order to address the water scarcity issues. Research on remediation of contaminated water has focused mainly on the removal of heavy metals such as Pb, Cd, Zn, Hg and Cu and neglected other inorganic pollutants. In this work we focus on the removal of anions, namely chromate and phosphate. Chromium is extensively used in the textile, leather and metallurgy industries and contaminates surface water and groundwater when inadequately treated industrial effluents are discharged. Chromium has been associated with irregular sugar metabolism, nosebleeds and ulcers, and it is also carcinogenic. The phosphate ion is an essential micronutrient responsible for healthy plant growth. However, excess phosphate intake stimulates rapid growth of photosynthetic algae and cyanobacteria, resulting in eutrophication. This phenomenon (algal bloom) causes other organisms to die due to reduced oxygen in the water. In order to offer remediation measures, this study reports the use of electrospun nanofibres for the removal of chromate and phosphate anions. Adsorption experiments were carried out using nanofibres electrospun from chitosan and polyacrylamide polymer blends, cross-linked with glutaraldehyde. Quantification of chromium was done using ICP-OES while UV-Vis spectrophotometry was used for the determination of phosphates. Batch adsorption experiments were done to determine optimum adsorption parameters such as pH, contact time, temperature and initial analyte concentration. Removal of the ions using a flow-adsorption technique through a micro-column was performed. The experimental data obtained were analysed using Langmuir and Freundlich models to study the adsorption mechanisms. The nanofibres had an adsorption capacity for Cr(VI) and PO43- of 0.26 mg g-1 and 392 mg g-1, respectively, and removal efficiencies of 93% and 97.4%, in the same order, in synthetic water

  14. Patterned, highly stretchable and conductive nanofibrous PANI/PVDF strain sensors based on electrospinning and in situ polymerization

    Science.gov (United States)

    Yu, Gui-Feng; Yan, Xu; Yu, Miao; Jia, Meng-Yang; Pan, Wei; He, Xiao-Xiao; Han, Wen-Peng; Zhang, Zhi-Ming; Yu, Liang-Min; Long, Yun-Ze

    2016-01-01

    A facile fabrication strategy via electrospinning and followed by in situ polymerization to fabricate a patterned, highly stretchable, and conductive polyaniline/poly(vinylidene fluoride) (PANI/PVDF) nanofibrous membrane is reported. Owing to the patterned structure, the nanofibrous PANI/PVDF strain sensor can detect a strain up to 110%, for comparison, which is 2.6 times higher than the common nonwoven PANI/PVDF mat and much larger than the previously reported values (usually less than 15%). Meanwhile, the conductivity of the patterned strain sensor shows a linear response to the applied strain in a wide range from 0% to about 85%. Additionally, the patterned PANI/PVDF strain sensor can completely recover to its original electrical and mechanical values within a strain range of more than 22%, and exhibits good durability over 10 000 folding-unfolding tests. Furthermore, the strain sensor also can be used to detect finger motion. The results demonstrate promising application of the patterned nanofibrous membrane in flexible electronic fields.A facile fabrication strategy via electrospinning and followed by in situ polymerization to fabricate a patterned, highly stretchable, and conductive polyaniline/poly(vinylidene fluoride) (PANI/PVDF) nanofibrous membrane is reported. Owing to the patterned structure, the nanofibrous PANI/PVDF strain sensor can detect a strain up to 110%, for comparison, which is 2.6 times higher than the common nonwoven PANI/PVDF mat and much larger than the previously reported values (usually less than 15%). Meanwhile, the conductivity of the patterned strain sensor shows a linear response to the applied strain in a wide range from 0% to about 85%. Additionally, the patterned PANI/PVDF strain sensor can completely recover to its original electrical and mechanical values within a strain range of more than 22%, and exhibits good durability over 10 000 folding-unfolding tests. Furthermore, the strain sensor also can be used to detect finger

  15. A nanofibrous electrospun patch to maintain human mesenchymal cell stemness.

    Science.gov (United States)

    Pandolfi, L; Furman, N Toledano; Wang, Xin; Lupo, C; Martinez, J O; Mohamed, M; Taraballi, F; Tasciotti, E

    2017-03-01

    Mesenchymal stem cells (MSCs) have been extensively investigated in regenerative medicine because of their crucial role in tissue healing. For these properties, they are widely tested in clinical trials, usually injected in cell suspension or in combination with tridimensional scaffolds. However, scaffolds can largely affect the fates of MSCs, inducing a progressive loss of functionality overtime. The ideal scaffold must delay MSCs differentiation until paracrine signals from the host induce their change. Herein, we proposed a nanostructured electrospun gelatin patch as an appropriate environment where human MSCs (hMSCs) can adhere, proliferate, and maintain their stemness. This patch exhibited characteristics of a non-linear elastic material and withstood degradation up to 4 weeks. As compared to culture and expansion in 2D, hMSCs on the patch showed a similar degree of proliferation and better maintained their progenitor properties, as assessed by their superior differentiation capacity towards typical mesenchymal lineages (i.e. osteogenic and chondrogenic). Furthermore, immunohistochemical analysis and longitudinal non-invasive imaging of inflammatory response revealed no sign of foreign body reaction for 3 weeks. In summary, our results demonstrated that our biocompatible patch favored the maintenance of undifferentiated hMSCs for up to 21 days and is an ideal candidate for tridimensional delivery of hMSCs. The present work reports a nanostructured patch gelatin-based able to maintain in vitro hMSCs stemness features. Moreover, hMSCs were able to differentiate toward osteo- and chondrogenic lineages once induces by differentiative media, confirming the ability of this patch to support stem cells for a potential in vivo application. These attractive properties together with the low inflammatory response in vivo make this patch a promising platform in regenerative medicine.

  16. Enhanced vapor transport in membrane distillation via functionalized carbon nanotubes anchored into electrospun nanofibres

    Science.gov (United States)

    Kyoungjin An, Alicia; Lee, Eui-Jong; Guo, Jiaxin; Jeong, Sanghyun; Lee, Jung-Gil; Ghaffour, Noreddine

    2017-01-01

    To ascertain membrane distillation (MD) as an emerging desalination technology to meet the global water challenge, development of membranes with ideal material properties is crucial. Functionalized carbon nanotubes (CNTs) were anchored to nanofibres of electrospun membranes. Covalent modification and fluorination of CNTs improved their dispersibility and interfacial interaction with the polymer membrane, resulting in well-aligned CNTs inside crystalline fibres with superhydrophobicity. Consideration for the chemical/physical properties of the CNT composite membranes and calculation of their theoretical fluxes revealed the mechanism of MD: CNTs facilitated the repulsive force for Knudsen and molecular diffusions, reduced the boundary-layer effect in viscous flow, and assisted surface diffusion, allowing for fast vapor transport with anti-wetting. This study shows that the role of CNTs and an optimal composite ratio can be used to reduce the gap between theoretical and experimental approaches to desalination.

  17. Enhanced vapor transport in membrane distillation via functionalized carbon nanotubes anchored into electrospun nanofibres

    Science.gov (United States)

    Kyoungjin An, Alicia; Lee, Eui-Jong; Guo, Jiaxin; Jeong, Sanghyun; Lee, Jung-Gil; Ghaffour, Noreddine

    2017-01-01

    To ascertain membrane distillation (MD) as an emerging desalination technology to meet the global water challenge, development of membranes with ideal material properties is crucial. Functionalized carbon nanotubes (CNTs) were anchored to nanofibres of electrospun membranes. Covalent modification and fluorination of CNTs improved their dispersibility and interfacial interaction with the polymer membrane, resulting in well-aligned CNTs inside crystalline fibres with superhydrophobicity. Consideration for the chemical/physical properties of the CNT composite membranes and calculation of their theoretical fluxes revealed the mechanism of MD: CNTs facilitated the repulsive force for Knudsen and molecular diffusions, reduced the boundary-layer effect in viscous flow, and assisted surface diffusion, allowing for fast vapor transport with anti-wetting. This study shows that the role of CNTs and an optimal composite ratio can be used to reduce the gap between theoretical and experimental approaches to desalination. PMID:28134288

  18. Monitoring of Glucose in Beer Brewing by a Carbon Nanotubes Based Nylon Nanofibrous Biosensor

    Directory of Open Access Journals (Sweden)

    Marco Mason

    2016-01-01

    Full Text Available This work presents the design, preparation, and characterization of a novel glucose electrochemical biosensor based on the immobilization of glucose oxidase (GOX into a nylon nanofibrous membrane (NFM prepared by electrospinning and functionalized with multiwalled carbon nanotubes (CNT. A disc of such GOX/CNT/NFM membrane (40 μm in thickness was used for coating the surface of a glassy carbon electrode. The resulting biosensor was characterized by cyclic voltammetry and chronoamperometry, with ferrocene methanol as mediator. The binding of GOX around the CNT/NFM greatly enhances the electron transfer, which results in a biosensor with a current five times higher than without CNT. The potential usefulness of the proposed biosensor was demonstrated with the analysis of glucose in commercial beverages and along the monitoring of the brewing process for making beer, from the mashing to the fermentation steps.

  19. Enhanced vapor transport in membrane distillation via functionalized carbon nanotubes anchored into electrospun nanofibres

    KAUST Repository

    An, Alicia Kyoungjin

    2017-01-30

    To ascertain membrane distillation (MD) as an emerging desalination technology to meet the global water challenge, development of membranes with ideal material properties is crucial. Functionalized carbon nanotubes (CNTs) were anchored to nanofibres of electrospun membranes. Covalent modification and fluorination of CNTs improved their dispersibility and interfacial interaction with the polymer membrane, resulting in well-aligned CNTs inside crystalline fibres with superhydrophobicity. Consideration for the chemical/physical properties of the CNT composite membranes and calculation of their theoretical fluxes revealed the mechanism of MD: CNTs facilitated the repulsive force for Knudsen and molecular diffusions, reduced the boundary-layer effect in viscous flow, and assisted surface diffusion, allowing for fast vapor transport with anti-wetting. This study shows that the role of CNTs and an optimal composite ratio can be used to reduce the gap between theoretical and experimental approaches to desalination.

  20. A smart nanofibrous material for adsorbing and detecting elemental mercury in air

    Directory of Open Access Journals (Sweden)

    A. Macagnano

    2017-06-01

    Full Text Available The combination of the affinity of gold for mercury and nanosized frameworks has allowed for the design and fabrication of novel kinds of sensors with promising sensing features for environmental applications. Specifically, conductive sensors based on composite nanofibrous electrospun layers of titania easily decorated with gold nanoparticles were developed to obtain nanostructured hybrid materials capable of entrapping and revealing gaseous elemental mercury (GEM traces from the environment. The electrical properties of the resulting chemosensors were measured. A few minutes of air sampling were sufficient to detect the concentration of mercury in the air, ranging between 20 and 100 ppb, without using traps or gas carriers (LOD: 1.5 ppb. Longer measurements allowed the sensor to detect lower concentrations of GEM. The resulting chemosensors are expected to be low cost and very stable (due to the peculiar structure, requiring low power, low maintenance, and simple equipment.

  1. Electrospun magnetic nanofibre mats – A new bondable biomaterial using remotely activated magnetic heating

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Yi [Department of Materials Engineering, University of British Columbia, Vancouver (Canada); Key Laboratory of Science & Technology of Eco-Textile, Ministry of Education, College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, Shanghai (China); Leung, Victor; Yuqin Wan, Lynn [Department of Materials Engineering, University of British Columbia, Vancouver (Canada); Dutz, Silvio [Institut für Biomedizinische Technik und Informatik, Technische Universität Ilmenau (Germany); Department of Nano Biophotonics, Leibniz Institute of Photonic Technology, Jena (Germany); Ko, Frank K., E-mail: frank.ko@ubc.ca [Department of Materials Engineering, University of British Columbia, Vancouver (Canada); Häfeli, Urs O., E-mail: urs.hafeli@ubc.ca [Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver (Canada)

    2015-04-15

    A solvothermal process was adopted to produce hydrophilic magnetite (Fe{sub 3}O{sub 4}) 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.

  2. Effect of carbon nanofibre addition on the mechanical properties of different f carbon-epoxy composites

    Indian Academy of Sciences (India)

    I Srikanth; Suresh Kumar; Vajinder Singh; B Rangababu; Partha Ghosal; Ch Subrahmanyam

    2015-04-01

    Carbon-epoxy (C-epoxy) laminated composites having different fibre volume fractions (40, 50, 60 and 70) were fabricated with and without the addition of aminofunctionalized carbon nanofibres (A-CNF). Flexural strength, interlaminar shear strength (ILSS) and tensile strength of the composite laminates were determined. It was observed that, the ability of A-CNF to enhance the mechanical properties of C-epoxy diminished significantly as the fibre volume fraction (f) of the C-epoxy increased from 40 to 60. At 70f, the mechanical properties of the A-CNF reinforced C-epoxy were found to be lower compared to the C-epoxy composite made without the addition of A-CNF. In this paper suitable mechanisms for the observed trends are proposed on the basis of the fracture modes of the composite.

  3. Relationships between phase morphology and deformation mechanisms in polymer nanocomposite nanofibres prepared by an electrospinning process.

    Science.gov (United States)

    Kim, G M; Lach, R; Michler, G H; Pötschke, P; Albrecht, K

    2006-02-28

    Relationships between phase morphology and mechanical deformation processes in various electrospun polymer nanocomposite nanofibres (PNCNFs) containing different types of one-, two- and three-dimensional nanofiller have been investigated by transmission electron microscopy using in situ tensile techniques. From the study of the phase structure of electrospun PNCNFs, two morphological standard types are classified for the analysis of deformation mechanisms: the binary system (polymer matrix and nanofillers), and the ternary system (polymer matrix, nanofillers and nanopores on the fibres surface). According to these categories, deformation processes have been characterized, and different schematic models for these processes are proposed. The finding of importance in the present work is a brittle-to-ductile transition in polymer nanocomposite fibres during in situ tensile deformation processes. This unique feature in the deformation behaviour of electrospun PNCNFs provides an optimal balance of stiffness, strength and toughness for use as reinforcing elements in a polymer based composite of a new kind.

  4. Photocatalysis of Yttrium Doped BaTiO3 Nanofibres Synthesized by Electrospinning

    Directory of Open Access Journals (Sweden)

    Zhenjiang Shen

    2015-01-01

    Full Text Available Yttrium doped barium titanate (BT nanofibres (NFs with significant photocatalytic effect were successfully synthesized by electrospinning. Considering the necessary factors for semiconductor photocatalysts, a well-designed procedure was carried out to produce yttrium doped BT (BYT NFs. In contrast to BYT ceramics powders and BT NFs, BYT NFs with pure perovskite phase showed much enhanced performance of photocatalysis. The surface modification in electrospinning and subsequent annealing, the surface spreading of transition metal yttrium, and the narrowed band gap energy in yttrium doping were all contributed to the final novel photocatalytic effect. This work provides a direct and efficient route to obtain doped NFs, which has a wide range of potential applications in areas based on complex compounds with specific surface and special doping effect.

  5. Antibacterial effects of electrospun chitosan/poly(ethylene oxide) nanofibrous membranes loaded with chlorhexidine and silver.

    Science.gov (United States)

    Song, Jiankang; Remmers, Stefan J A; Shao, Jinlong; Kolwijck, Eva; Walboomers, X Frank; Jansen, John A; Leeuwenburgh, Sander C G; Yang, Fang

    2016-07-01

    To prevent percutaneous device associated infections (PDAIs), we prepared electrospun chitosan/poly(ethylene oxide) (PEO) nanofibrous membrane containing silver nanoparticles as an implantable delivery vehicle for the dual release of chlorhexidine and silver ions. We observed that the silver nanoparticles were distributed homogeneously throughout the fibers, and a fast release of chlorhexidine in 2days and a sustained release of silver ions for up to 28days. The antibacterial efficacy of the membranes against Staphylococcus aureus showed that the membranes exhibited an obvious inhibition zone upon loading with either chlorhexidine (20μg or more per membrane) or AgNO3 (1 and 5wt% to polymer). Furthermore, long-term antibacterial effect up to 4days was verified using membranes containing 5wt% AgNO3. The results suggest that the membranes have strong potential to act as an active antibacterial dressing for local delivery of antibacterial agents to prevent PDAIs.

  6. Array of nanofibrous polyaniline-based sensors with different chemo-structural assembling

    Science.gov (United States)

    Macagnano, A.; Zampetti, E.; Pantalei, S.; Italia, M.; Spinella, C.; Bearzotti, A.

    2009-05-01

    Among various attempts of mimicking olfactory system the present work focuses on the sensorial surface of mammalian olfactory cells. The aim of this research is to develop, in a single step, synthetic fibres mimicking the long, no motile cilia of the olfactory cells. Electrospun conductive nanofibrous layers of doped polyaniline, suitably blended to a group of polymers capable to carry the jet, have been easily assembled on chemoresistors (interdigital microelectrodes, IDEs). Such highly sensitive sensors have been able to detect gases in traces of relevant medical significance, mainly because of high density of sorption sites of the sensor. Changing the carriers, the range of sensitivity to gases could be tuned. The key role of the selected carrier polymers (polyethylenoxide of different molecular weights, PEO, polyvinilpyrrolidone, PVP, and polystyrene, PS) to the final sensor features has been highlighted by morphology analysis (texture analysis) and electrical measurements before and after gas interaction.

  7. Electrospun Superhydrophobic Organic/Inorganic Composite Nanofibrous Membranes for Membrane Distillation.

    Science.gov (United States)

    Li, Xiong; Yu, Xufeng; Cheng, Cheng; Deng, Li; Wang, Min; Wang, Xuefen

    2015-10-07

    Electrospun superhydrophobic organic/inorganic composite nanofibrous membranes exhibiting excellent direct contact membrane distillation (DCMD) performance were fabricated by a facile route combining the hydrophobization of silica nanoparticles (SiO2 NPs) and colloid electrospinning of the hydrophobic silica/poly(vinylidene fluoride) (PVDF) matrix. Benefiting from the utilization of SiO2 NPs with three different particle sizes, the electrospun nanofibrous membranes (ENMs) were endowed with three different delicate nanofiber morphologies and fiber diameter distribution, high porosity, and superhydrophobic property, which resulted in excellent waterproofing and breathability. Significantly, structural attributes analyses have indicated the major contributing role of fiber diameter distribution on determining the augment of permeate vapor flux through regulating mean flow pore size (MFP). Meanwhile, the extremely high liquid entry pressure of water (LEPw, 2.40 ± 0.10 bar), robust nanofiber morphology of PVDF immobilized SiO2 NPs, remarkable mechanical properties, thermal stability, and corrosion resistance endowed the as-prepared membranes with prominent desalination capability and stability for long-term MD process. The resultant choreographed PVDF/silica ENMs with optimized MFP presented an outstanding permeate vapor flux of 41.1 kg/(m(2)·h) and stable low permeate conductivity (∼2.45 μs/cm) (3.5 wt % NaCl salt feed; ΔT = 40 °C) over a DCMD test period of 24 h without membrane pores wetting detected. This result was better than those of typical commercial PVDF membranes and PVDF and modified PVDF ENMs reported so far, suggesting them as promising alternatives for MD applications.

  8. Evaluation of emulsion electrospun polycaprolactone/hyaluronan/epidermal growth factor nanofibrous scaffolds for wound healing.

    Science.gov (United States)

    Wang, Zhenbei; Qian, Yuna; Li, Linhao; Pan, Lianhong; Njunge, Lucy W; Dong, Lili; Yang, Li

    2016-01-01

    Wound healing scaffolds provide cells with structural integrity and can also deliver biological agents to establish a skin tissue-specific microenvironment to regulate cell functions and to accelerate the healing process. In this study, we fabricated biodegradable nanofibrous scaffolds with an emulsion electrospinning technique. The scaffolds were composed of polycaprolactone, hyaluronan and encapsulating epidermal growth factor. The morphology and core-sheath structure of the nanofibers were characterized by scanning electron microscopy and transmission electron microscopy. The scaffolds were also characterized for chemical composition and hydrophilicity with a Fourier-transform infrared analysis, energy dispersive spectroscopy and the water contact angle. An in vitro model protein bovine serum albumin and epidermal growth factor release study was conducted to evaluate the sustained release potential of the core-sheath structured nanofibers with and without the hyaluronan component. Additionally, an in vitro cultivation of human skin keratinocytes (HaCaT) and fibroblasts on polycaprolactone/hyaluronan and polycaprolactone/hyaluronan-epidermal growth factor scaffolds showed a significant synergistic effect of hyaluronan and epidermal growth factor on cell proliferation and infiltration. Furthermore, there was an up-regulation of the wound-healing-related genes collagen I, collagen III and TGF-β in polycaprolactone/hyaluronan/epidermal growth factor scaffolds compared with control groups. In the full-thickness wound model, the enhanced regeneration of fully functional skin was facilitated by epidermal regeneration in the polycaprolactone/hyaluronan/epidermal growth factor treatment group. Our findings suggest that bioactivity and hemostasis of the hyaluronan-based nanofibrous scaffolds have the capability to encapsulate and control the release of growth factors that can serve as skin tissue engineering scaffolds for wound healing.

  9. The in vivo performance of small-caliber nanofibrous polyurethane vascular grafts

    Directory of Open Access Journals (Sweden)

    Hu Zuo-jun

    2012-12-01

    Full Text Available Abstract Background In a previous in vitro study, we confirmed that small-caliber nanofibrous polyurethane (PU vascular grafts have favorable mechanical properties and biocompatibility. In the present study, we examined the in vivo biocompatibility and stability of these grafts. Methods Forty-eight adult male beagle dogs were randomly divided into two groups receiving, respectively, polyurethane (PU or polytetrafluoroethylene (PTFE grafts (n = 24 animals / group. Each group was studied at 4, 8, 12, and 24 weeks after graft implantation. Blood flow was analyzed by color Doppler ultrasound and computed tomography angiography. Patency rates were judged by animal survival rates. Coverage with endothelial and smooth muscle cells was characterized by hematoxylin-eosin and immunohistological staining, and scanning electron microscopy (SEM. Results Patency rates were significantly higher in the PU group (p = 0.02 vs. PTFE group. During the first 8 weeks, endothelial cells gradually formed a continuous layer on the internal surface of PU grafts, whereas coverage of PTFE graft by endothelial cells was inhomogeneous. After 12 weeks, neointimal thickness remained constant in the PU group, while PTFE group showed neointimal hyperplasia. At 24 weeks, some anastomotic sites of PTFE grafts became stenotic (p = 0.013 vs. PU group. Immunohistological staining revealed a continuous coverage by endothelial cells and an orderly arrangement of smooth muscle cells on PU grafts. Further, SEM showed smooth internal surfaces in PU grafts without thrombus or obvious neointimal hyperplasia. Conclusions Small-caliber nanofibrous PU vascular grafts facilitate the endothelialization process, prevent excessive neointimal hyperplasia, and improve patency rates.

  10. Engineering meniscus structure and function via multi-layered mesenchymal stem cell-seeded nanofibrous scaffolds.

    Science.gov (United States)

    Fisher, Matthew B; Henning, Elizabeth A; Söegaard, Nicole; Bostrom, Marc; Esterhai, John L; Mauck, Robert L

    2015-06-01

    Despite advances in tissue engineering for the knee meniscus, it remains a challenge to match the complex macroscopic and microscopic structural features of native tissue, including the circumferentially and radially aligned collagen bundles essential for mechanical function. To mimic this structural hierarchy, this study developed multi-lamellar mesenchymal stem cell (MSC)-seeded nanofibrous constructs. Bovine MSCs were seeded onto nanofibrous scaffolds comprised of poly(ε-caprolactone) with fibers aligned in a single direction (0° or 90° to the scaffold long axis) or circumferentially aligned (C). Multi-layer groups (0°/0°/0°, 90°/90°/90°, 0°/90°/0°, 90°/0°/90°, and C/C/C) were created and cultured for a total of 6 weeks under conditions favoring fibrocartilaginous tissue formation. Tensile testing showed that 0° and C single layer constructs had stiffness values several fold higher than 90° constructs. For multi-layer groups, the stiffness of 0°/0°/0° constructs was higher than all other groups, while 90°/90°/90° constructs had the lowest values. Data for collagen content showed a general positive interactive effect for multi-layers relative to single layer constructs, while a positive interaction for stiffness was found only for the C/C/C group. Collagen content and cell infiltration occurred independent of scaffold alignment, and newly formed collagenous matrix followed the scaffold fiber direction. Structural hierarchies within multi-lamellar constructs dictated biomechanical properties, and only the C/C/C constructs with non-orthogonal alignment within layers featured positive mechanical reinforcement as a consequence of the layered construction. These multi-layer constructs may serve as functional substitutes for the meniscus as well as test beds to understand the complex mechanical principles that enable meniscus function.

  11. Development of novel electrospun nanofibrous scaffold from P. ricini and A. mylitta silk fibroin blend with improved surface and biological properties

    Energy Technology Data Exchange (ETDEWEB)

    Panda, N.; Bissoyi, A.; Pramanik, K.; Biswas, A., E-mail: amitb79@gmail.com

    2015-03-01

    Biomaterials that stimulate cell attachment and proliferation without any surface modification (e.g. RGD coating) provide potent and cost effective scaffold for regenerative medicine. This study assessed the physico-chemical properties and cell supportive potential of a silk fibroin blend scaffold derived from eri (Philosamia ricini) and tasar (Antheraea mylitta) silk (ET) respectively by electrospinning process. The scanning electron microscopy and transmission electron microscopy study found that the fiber diameters are in 200 to 800 nm range with flat morphology. The porosity of ET scaffold is found to be 79 ± 5% with majority of pore diameter between 2.5 to 5 nm. Similarly, Bombyx mori (BM) silk fibroin and gelatin nanofibrous scaffolds were prepared and taken as control. The ultimate tensile strength of the ET and BM scaffold are found to be 1.83 ± 0.13 MPa and 1.47 ± 0.10 MPa respectively. The measured contact angle (a measure of hydrophilicity) for ET (54.7° ± 1.8°) is found to be lower than BM (62° ± 2.3°). The ability to deposit apatite over ET is comparable to that of BM nanofibers. All the scaffolds were seeded with cord blood derived mesenchymal stem cells (hMSCs) and cultured for 14 days in vitro. The immunofluorescence study reveals enhanced cell attachment with higher metabolic activity for MSCs grown over ET than BM and gelatin. The ET scaffold also demonstrated expression of higher amount cell adhesion molecules (CD29/CD44) and higher proliferation rate than BM and gelatin as confirmed by MTT assay, DNA content estimation assay, flow cytometry study and SEM study. Overall, it may be concluded that ET scaffold may have potential in developing bone tissue grafts for clinical applications in the future. - Highlights: • We have fabricated eri–tasar blended electrospun silk fibroin nanofiber with superior surface property. • The hydrophilicity is higher than the silk fibroin nanofiber derived from Bombyx mori (BM). • The nanofibrous

  12. Drug release profile in core-shell nanofibrous structures: a study on Peppas equation and artificial neural network modeling.

    Science.gov (United States)

    Maleki, Mahboubeh; Amani-Tehran, Mohammad; Latifi, Masoud; Mathur, Sanjay

    2014-01-01

    Release profile of drug constituent encapsulated in electrospun core-shell nanofibrous mats was modeled by Peppas equation and artificial neural network. Core-shell fibers were fabricated by co-axial electrospinning process using tetracycline hydrochloride (TCH) as the core and poly(l-lactide-co-glycolide) (PLGA) or polycaprolactone (PCL) as the shell materials. The density and hydrophilicity of the shell polymers, feed rates and concentrations of core and shell phases, the contribution of TCH in core material and electrical field were the parameters fed to the perceptron network to predict Peppas constants in order to derive release pattern. This study demonstrated the viability of the prediction tool in determining drug release profile of electrospun core-shell nanofibrous scaffolds.

  13. A biologically inspired attachable, self-standing nanofibrous membrane for versatile use in oil-water separation

    Science.gov (United States)

    Tenjimbayashi, Mizuki; Sasaki, Kaichi; Matsubayashi, Takeshi; Abe, Jyunichiro; Manabe, Kengo; Nishioka, Sachiko; Shiratori, Seimei

    2016-05-01

    Uloborus walckenaerius spider webs provided the inspiration for attachable, self-standing nanofibre sheets. The developed product adds selective wettability against oil-water mixtures to both 2D and 3D materials by attaching or covering them, leading to successful separation through a facile, scalable and low-cost process.Uloborus walckenaerius spider webs provided the inspiration for attachable, self-standing nanofibre sheets. The developed product adds selective wettability against oil-water mixtures to both 2D and 3D materials by attaching or covering them, leading to successful separation through a facile, scalable and low-cost process. Electronic supplementary information (ESI) available: Experimental section, designing procedure, cost, cross sectional SEM, influence of NFs-S components to wettability, thickness, fibre diameter and flexibility, surface tension vs. contact angle, SEM images after extraction of oil, characteristics of testing oil, large scale-fabrication of NFs-S. See DOI: 10.1039/c6nr03349k

  14. Poly(acrylonitrile-co-itaconic acid)–poly(3,4-ethylenedioxythiophene) and poly(3-methoxythiophene) nanoparticles and nanofibres

    Indian Academy of Sciences (India)

    HAVVA BASKAN; CEM UNSAL; HALE KARAKAS; A SEZAI SARAC

    2017-09-01

    This work aimed to produce poly(acrylonitrile-co-itaconic acid) (P(AN-co-IA)) nanocomposites with poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(3-methoxythiophene) (PMOT). An anionic surfactant sodium dodecyl benzenesulphonate was used in emulsion polymerization for nanocomposite production. Incorporations of PEDOT and PMOT on the nanoparticles were characterized by scanning electron microscopy (SEM), atomic force microscopy, Fourier transforminfrared-attenuated total reflectance spectroscopy and ultra-violet spectroscopy. These nanoparticles were blended withPAN and the blends were electrospun to produce P(AN-co-IA)–polythiophene-derivative-based nanofibres, and the obtainednanofibres were characterized by SEM and energy dispersive spectroscopy. In addition, electrochemical impedance studiesconducted on nanofibres showed that PEDOT and PMOT in matrix polymer P(AN-co-IA) exhibited capacitive behaviourcomparable to that of ITO–PET. Their capacitive behaviour changed with the amount of electroactive polymer.

  15. Facile Fabrication of ZnO/TiO2 Heterogeneous Nanofibres and Their Photocatalytic Behaviour and Mechanism towards Rhodamine B

    OpenAIRE

    JiaDong Chen; WeiSha Liao; Ying Jiang; DanNi Yu; MeiLing Zou; Han Zhu; Ming Zhang; MingLiang Du

    2016-01-01

    In this study, novel titanium dioxide (TiO2) and zinc oxide (ZnO) hybrid photocatalysts in the form of nanofibres were fabricated by a facile method using electrospinning followed by a calcination process. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were employed to investigate the morphology and structure of the heterogeneous nanofi‐ bres. The photocatalytic performances were evaluated via the ...

  16. Surface modification of nanofibrous polycaprolactone/gelatin composite scaffold by collagen type I grafting for skin tissue engineering

    Energy Technology Data Exchange (ETDEWEB)

    Gautam, Sneh [Department of Polymer and Process Engineering, Indian Institute of Technology Roorkee (India); Chou, Chia-Fu [Institute of Physics, Academia Sinica, Taipei, Taiwan (China); Dinda, Amit K. [Department of Pathology, All India Institute of Medical Science, New Delhi (India); Potdar, Pravin D. [Department of Molecular Medicine and Biology, Jaslok Hospital and Research Centre, Mumbai (India); Mishra, Narayan C., E-mail: mishrawise@gmail.com [Department of Polymer and Process Engineering, Indian Institute of Technology Roorkee (India)

    2014-01-01

    In the present study, a tri-polymer polycaprolactone (PCL)/gelatin/collagen type I composite nanofibrous scaffold has been fabricated by electrospinning for skin tissue engineering and wound healing applications. Firstly, PCL/gelatin nanofibrous scaffold was fabricated by electrospinning using a low cost solvent mixture [chloroform/methanol for PCL and acetic acid (80% v/v) for gelatin], and then the nanofibrous PCL/gelatin scaffold was modified by collagen type I (0.2–1.5 wt.%) grafting. Morphology of the collagen type I-modified PCL/gelatin composite scaffold that was analyzed by field emission scanning electron microscopy (FE-SEM), showed that the fiber diameter was increased and pore size was decreased by increasing the concentration of collagen type I. Fourier transform infrared (FT-IR) spectroscopy and thermogravimetric (TG) analysis indicated the surface modification of PCL/gelatin scaffold by collagen type I immobilization on the surface of the scaffold. MTT assay demonstrated the viability and high proliferation rate of L929 mouse fibroblast cells on the collagen type I-modified composite scaffold. FE-SEM analysis of cell-scaffold construct illustrated the cell adhesion of L929 mouse fibroblasts on the surface of scaffold. Characteristic cell morphology of L929 was also observed on the nanofiber mesh of the collagen type I-modified scaffold. Above results suggest that the collagen type I-modified PCL/gelatin scaffold was successful in maintaining characteristic shape of fibroblasts, besides good cell proliferation. Therefore, the fibroblast seeded PCL/gelatin/collagen type I composite nanofibrous scaffold might be a potential candidate for wound healing and skin tissue engineering applications. - Highlights: • PCL/gelatin/collagen type I scaffold was fabricated for skin tissue engineering. • PCL/gelatin/collagen type I scaffold showed higher fibroblast growth than PCL/gelatin one. • PCL/gelatin/collagen type I might be one of the ideal scaffold for

  17. Thin and flexible solid-state organic ionic plastic crystal-polymer nanofibre composite electrolytes for device applications.

    Science.gov (United States)

    Howlett, Patrick C; Ponzio, Florian; Fang, Jian; Lin, Tong; Jin, Liyu; Iranipour, Nahid; Efthimiadis, Jim

    2013-09-07

    All solid-state organic ionic plastic crystal-polymer nanofibre composite electrolytes are described for the first time. The new composite materials exhibit enhanced conductivity, excellent thermal, mechanical and electrochemical stability and allow the production of optically transparent, free-standing, flexible, thin film electrolytes (10's μms thick) for application in electrochemical devices. Stable cycling of a lithium cell incorporating the new composite electrolyte is demonstrated, including cycling at lower temperatures than previously possible with the pure material.

  18. Fabrication and characterization of PVA, PVA/chitosan, and PVA/cyanobacterial exopolysaccharide nanofibrous composite nanofiltration membranes prepared by electrospinning

    OpenAIRE

    2013-01-01

    Apresentação efetuada no "245th ACS National Meeting and Exposition", em New Orleans, Louisiana, 2013 A series of poly(vinyl alcohol) (PVA), PVA/chitosan (CS) and PVA/cyanobacterial exopolysaccharide (EPS) blend nanofibrous membranes were fabricated by electrospinning using a microfiltration poly(vinylidene fluoride) (PVDF) as a basal membrane, in order to obtain thin-layer composite (TFC) nanofiltration membranes. The morphology, diameter, structure, mechanical and thermal characteristics...

  19. POTENTIAL APPLICATIONS OF TRANSPARENT FABRIC BASED ON NANOFIBRES FOR THE STRENGTHENING OF PLASTERS DECORATED WITH PAINTINGS AND FRESCOES

    Directory of Open Access Journals (Sweden)

    Klára Kroftová

    2015-10-01

    Full Text Available Nanomaterials have been increasingly used in the construction industry in the last decades. Nanomaterials have been tested in specific applications focusing on the restoration and conservation of heritage buildings, mainly their surfaces. Nanofibre materials represent a separate area within this field of research and their applications in the construction and conservation practice are still very limited. The article summarizes the possibilities of strengthening plasters decorated with wall paintings with nanomaterials.

  20. Nanofibrous yet injectable polycaprolactone-collagen bone tissue scaffold with osteoprogenitor cells and controlled release of bone morphogenetic protein-2

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Gayathri; Bialorucki, Callan [Department of Bioengineering, College of Engineering, University of Toledo, Toledo, OH 43606 (United States); Yildirim-Ayan, Eda, E-mail: eda.yildirimayan@utoledo.edu [Department of Bioengineering, College of Engineering, University of Toledo, Toledo, OH 43606 (United States); Department of Orthopaedic Surgery, University of Toledo Medical Center, Toledo, OH 43614 (United States)

    2015-06-01

    In this work, we developed a nanofibrous, yet injectable orthobiologic tissue scaffold that is capable of hosting osteoprogenitor cells and controlling kinetic release profile of the encapsulated pro-osteogenic factor without diminishing its bioactivity over 21 days. This innovative injectable scaffold was synthesized by incorporating electrospun and subsequently O{sub 2} plasma-functionalized polycaprolactone (PCL) nanofibers within the collagen type-I solution along with MC3T3-E1 cells (pre-osteoblasts) and bone morphogenetic protein-2 (BMP2). Through changing the PCL nanofiber concentration within the injectable scaffolds, we were able to tailor the mechanical strength, protein retention capacity, bioactivity preservation, and osteoinductive potential of the scaffolds. The nanofibrous internal structure of the scaffold allowed us to use a low dose of BMP2 (200 ng/ml) to achieve osteoblastic differentiation in in vitro culture. The osteogenesis capacity of the injectable scaffolds were evaluated though measuring MC3T3-E1 cell proliferation, ALP activity, matrix mineralization, and early- and late-osteoblast specific gene expression profiles over 21 days. The results demonstrated that the nanofibrous injectable scaffold provides not only an osteoinductive environment for osteoprogenitor cells to differentiate, but also a suitable biomechanical and biochemical environment to act as a reservoir for osteogenic factors with controlled release profile. - Highlights: • Injectable nanofibrous scaffold with osteoprogenitor cells and BMP2 was synthesized. • PCL nanofiber concentration within collagen scaffold affected the BMP2 retention and bioactivity. • Optimal PCL concentration was identified for mechanical stability, injectability, and osteogenic activity. • Scaffolds exhibited long-term osteoinductive capacity for bone repair and regeneration.

  1. An Overview on Application of Natural Substances Incorporated with Electrospun Nanofibrous Scaffolds to Development of Innovative Wound Dressings.

    Science.gov (United States)

    Zarghami, Nosratollah; Sheervalilou, Roghayeh; Fattahi, Amir; Mohajeri, Abbas; Dadashpour, Mehdi; Pilehvar-Soltanahmadi, Younes

    2017-03-08

    Conventional dressings are cost-effective and highly absorbent, but not effectual enough to promote hemostasis, adherence and in holding a moist wound bed. Thanks to the developments in the field of nanotechnology and bioengineering, one of the promising current trends is to move progress of innovative wound dressings, merging the application of traditional healing agents and modern products/practices, such as hydrocolloids, hydrogels, films and nanofibers. The electrospun nanofibers webs can provide the essential parameters require for wound dressing to heal wounds including absorptivity, oxygen permeability, and non-adherence to the healing tissue, barrier to bacteria, bioactivity and occlusivity. The modern wound dressings materials made of electrospun nanofibers contain various traditional healing agents such as plant derived compounds could be beneficial to the healing of wounds. Natural substances have been used in skin wound care for many years because of their therapeutic properties, including antimicrobial, antioxidant, anti-inflammatory and mitogenic activities. This review surveys on potentials of electrospun nanofibrous mats for wound dressing applications. Furthermore, loading of bioactive molecules and therapeutic agents into the nanofibrous mats especially natural compounds with the aim of fabrication novel bioactive electrospun nanofibrous mats for skin substitutes and wound dressings are discussed.

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

    Science.gov (United States)

    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.

  3. Sustained relief of pain from osteosynthesis surgery of rib fracture by using biodegradable lidocaine-eluting nanofibrous membranes.

    Science.gov (United States)

    Yu, Yi-Hsun; Hsu, Yung-Heng; Chou, Ying-Chao; Fan, Chin-Lung; Ueng, Steve W N; Kau, Yi-Chuan; Liu, Shih-Jung

    2016-10-01

    Various effective methods are available for perioperative pain control in osteosynthesis surgery, but they are seldom applied intraoperatively. The aim of this study was to evaluate a biodegradable poly([d,l]-lactide-co-glycolide) (PLGA)/lidocaine nanofibrous membrane for perioperative pain control in rib fracture surgery. Scanning electron microscopy showed high porosity of the membrane, and an ex vivo high-performance liquid chromatography study revealed an excellent release profile for both burst and controlled release of lidocaine within 30days. Additionally, the PLGA/lidocaine nanofibrous membrane was applied in an experimental rabbit rib osteotomy model. Implantation of the membrane around the osteotomized rib during osteosynthesis surgery resulted in a significant increase in weight gain, food and water consumption, and daily activity compared to the study group without the membrane. In addition, all osteotomized ribs were united. Thus, application of the PLGA/lidocaine nanofibrous membrane may be effective for sustained relief of pain in oeteosynthesis surgery. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Polydopamine-mediated surface functionalization of electrospun nanofibrous membranes: Preparation, characterization and their adsorption properties towards heavy metal ions

    Science.gov (United States)

    Wu, Chunlin; Wang, Heyun; Wei, Zhong; Li, Chuan; Luo, Zhidong

    2015-08-01

    In this paper, a simple and versatile approach for the fabrication of a polyethyleneimine (PEI)-functionalized nanofibrous membrane utilizing polydopamine (PDA) as a mediator is proposed. The morphology and structure of the PDA-coated and PEI-grafted nanofibrous membranes were confirmed using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. Due to a large specific surface area and long fibrous morphology, the synthesized membranes were used as novel adsorbents for copper ion (Cu2+) removal from aqueous solutions. The adsorption of Cu2+ was investigated on the synthesized membranes regarding the membrane dosages, initial solution pH values, initial solution concentrations, contact times and temperatures. In addition, the adsorption equilibrium data of PEI-grafted membranes were well fitted with the Langmuir adsorption isotherm, and a maximum adsorption capacity value of 33.59 mg g-1 was determined (while it was 21.94 mg g-1 for the PDA-coated membranes). The thermodynamic parameters indicated that Cu2+ absorption was a spontaneous and exothermic adsorption process. In addition, XPS peak differentiation imitating analysis permitted the proposal of a copper-amine coordination adsorption mechanism that can be used to explain changes in the adsorption properties compared to PDA coating nanofibrous membranes.

  5. Multi-hierarchical self-assembly of a collagen mimetic peptide from triple helix to nanofibre and hydrogel

    Science.gov (United States)

    O'Leary, Lesley E. R.; Fallas, Jorge A.; Bakota, Erica L.; Kang, Marci K.; Hartgerink, Jeffrey D.

    2011-10-01

    Replicating the multi-hierarchical self-assembly of collagen has long-attracted scientists, from both the perspective of the fundamental science of supramolecular chemistry and that of potential biomedical applications in tissue engineering. Many approaches to drive the self-assembly of synthetic systems through the same steps as those of natural collagen (peptide chain to triple helix to nanofibres and, finally, to a hydrogel) are partially successful, but none simultaneously demonstrate all the levels of structural assembly. Here we describe a peptide that replicates the self-assembly of collagen through each of these steps. The peptide features collagen's characteristic proline-hydroxyproline-glycine repeating unit, complemented by designed salt-bridged hydrogen bonds between lysine and aspartate to stabilize the triple helix in a sticky-ended assembly. This assembly is propagated into nanofibres with characteristic triple helical packing and lengths with a lower bound of several hundred nanometres. These nanofibres form a hydrogel that is degraded by collagenase at a similar rate to that of natural collagen.

  6. Enhanced in vitro angiogenic behaviour of human umbilical vein endothelial cells on thermally oxidized TiO2 nanofibrous surfaces

    Science.gov (United States)

    Tan, Ai Wen; Liau, Ling Ling; Chua, Kien Hui; Ahmad, Roslina; Akbar, Sheikh Ali; Pingguan-Murphy, Belinda

    2016-02-01

    One of the major challenges in bone grafting is the lack of sufficient bone vascularization. A rapid and stable bone vascularization at an early stage of implantation is essential for optimal functioning of the bone graft. To address this, the ability of in situ TiO2 nanofibrous surfaces fabricated via thermal oxidation method to enhance the angiogenic potential of human umbilical vein endothelial cells (HUVECs) was investigated. The cellular responses of HUVECs on TiO2 nanofibrous surfaces were studied through cell adhesion, cell proliferation, capillary-like tube formation, growth factors secretion (VEGF and BFGF), and angiogenic-endogenic-associated gene (VEGF, VEGFR2, BFGF, PGF, HGF, Ang-1, VWF, PECAM-1 and ENOS) expression analysis after 2 weeks of cell seeding. Our results show that TiO2 nanofibrous surfaces significantly enhanced adhesion, proliferation, formation of capillary-like tube networks and growth factors secretion of HUVECs, as well as leading to higher expression level of all angiogenic-endogenic-associated genes, in comparison to unmodified control surfaces. These beneficial effects suggest the potential use of such surface nanostructures to be utilized as an advantageous interface for bone grafts as they can promote angiogenesis, which improves bone vascularization.

  7. Coordination kinetics of different metal ions with the amidoximated polyacrylonitrile nanofibrous membranes and catalytic behaviors of their complexes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fu; Dong, Yong Chun; Kang, Wei Min; Cheng, Bowen; Qu, Xiang; Cui, Guixin [School of Textiles, Tianjin Polytechnic University, Tianjin (China)

    2016-12-15

    Two transition metal ions (Fe{sup 3+} and Cu{sup 2+}) and a rare earth metal ion (Ce{sup 3+}) were selected to coordinate with amidoximated polyacrylonitrile (PAN) nanofibrous membrane for preparing three metal modified PAN nanofibrous membrane complexes (M-AO-n-PANs, M = Fe, Cu, or Ce) as the heterogeneous Fenton catalysts for the dye degradation in water under visible irradiation. The coordination kinetics of three metal ions with modified PAN nanofibrous membranes was studied and the catalytic properties of the resulting complexes were also compared. The results indicated that increasing metal ion concentrations in solution or higher coordination temperature led to a significant increase in metal content, particularly in Fe and Cu contents of the complexes. Their coordination process could be described using Langmuir isotherm and pseudo-second-order kinetic equations. Moreover, Fe-AO-n-PAN had the best photocatalytic efficiency for the dye degradation in acidic medium, but a lower photocatalytic activity than Cu-AO-n-PAN in alkali medium.

  8. Protocol and cell responses in three-dimensional conductive collagen gel scaffolds with conductive polymer nanofibres for tissue regeneration.

    Science.gov (United States)

    Sirivisoot, Sirinrath; Pareta, Rajesh; Harrison, Benjamin S

    2014-02-06

    It has been established that nerves and skeletal muscles respond and communicate via electrical signals. In regenerative medicine, there is current emphasis on using conductive nanomaterials to enhance electrical conduction through tissue-engineered scaffolds to increase cell differentiation and tissue regeneration. We investigated the role of chemically synthesized polyaniline (PANI) and poly(3,4-ethylenedioxythiophene) (PEDOT) conductive polymer nanofibres for conductive gels. To mimic a naturally derived extracellular matrix for cell growth, type I collagen gels were reconstituted with conductive polymer nanofibres and cells. Cell viability and proliferation of PC-12 cells and human skeletal muscle cells on these three-dimensional conductive collagen gels were evaluated in vitro. PANI and PEDOT nanofibres were found to be cytocompatible with both cell types and the best results (i.e. cell growth and gel electrical conductivity) were obtained with a low concentration (0.5 wt%) of PANI. After 7 days of culture in the conductive gels, the densities of both cell types were similar and comparable to collagen positive controls. Moreover, PC-12 cells were found to differentiate in the conductive hydrogels without the addition of nerve growth factor or electrical stimulation better than collagen control. Importantly, electrical conductivity of the three-dimensional gel scaffolds increased by more than 400% compared with control. The increased conductivity and injectability of the cell-laden collagen gels to injury sites in order to create an electrically conductive extracellular matrix makes these biomaterials very conducive for the regeneration of tissues.

  9. Pectin-chitosan-PVA nanofibrous scaffold made by electrospinning and its potential use as a skin tissue scaffold.

    Science.gov (United States)

    Lin, Hsin-Yi; Chen, Hsin-Hung; Chang, Shih-Hsin; Ni, Tsung-Sheng

    2013-01-01

    Scaffolds made of chitosan nanofibers are often too mechanically weak for their application and often their manufacturing processes involve the use of harmful and flammable organic solvents. In the attempt to improve the mechanical properties of nanofibrous scaffolds made of chitosan without the use of harmful chemicals, pectin, an anionic polymer was blended with chitosan, a cationic polymer, to form a polyelectrolyte complex and electrospun into nanofibers for the first time. The electrospun chitosan-pectin scaffolds, when compared to electrospun chitosan scaffolds, had a 58% larger diameter, a 21% higher Young's modulus, a 162% larger strain at break, and a 104% higher ultimate tensile strength. Compared to the chitosan scaffolds, the chitosan-pectin scaffolds' swelling ratios decreased by 55% after 60 min in a saline solution and more quickly released the preloaded tetracycline HCl. The L929 fibroblast cells proliferated slightly slower on the chitosan-pectin scaffolds than on the chitosan scaffolds. Nonetheless, cells on both materials deposited similar levels of extracellular type I collagen on a per DNA basis. In conclusion, a novel chitosan-pectin nanofibrous scaffold with superior mechanical properties than a chitosan nanofibrous scaffold was successfully made without the use of harmful solvents.

  10. Multi-hierarchical self-assembly of a collagen mimetic peptide from triple helix to nanofibre and hydrogel.

    Science.gov (United States)

    O'Leary, Lesley E R; Fallas, Jorge A; Bakota, Erica L; Kang, Marci K; Hartgerink, Jeffrey D

    2011-08-28

    Replicating the multi-hierarchical self-assembly of collagen has long-attracted scientists, from both the perspective of the fundamental science of supramolecular chemistry and that of potential biomedical applications in tissue engineering. Many approaches to drive the self-assembly of synthetic systems through the same steps as those of natural collagen (peptide chain to triple helix to nanofibres and, finally, to a hydrogel) are partially successful, but none simultaneously demonstrate all the levels of structural assembly. Here we describe a peptide that replicates the self-assembly of collagen through each of these steps. The peptide features collagen's characteristic proline-hydroxyproline-glycine repeating unit, complemented by designed salt-bridged hydrogen bonds between lysine and aspartate to stabilize the triple helix in a sticky-ended assembly. This assembly is propagated into nanofibres with characteristic triple helical packing and lengths with a lower bound of several hundred nanometres. These nanofibres form a hydrogel that is degraded by collagenase at a similar rate to that of natural collagen.

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

    Science.gov (United States)

    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.

  12. Nanofibrous Chitosan-Polyethylene Oxide Engineered Scaffolds: A Comparative Study between Simulated Structural Characteristics and Cells Viability

    Directory of Open Access Journals (Sweden)

    Mohammad Kazemi Pilehrood

    2014-01-01

    Full Text Available 3D nanofibrous chitosan-polyethylene oxide (PEO scaffolds were fabricated by electrospinning at different processing parameters. The structural characteristics, such as pore size, overall porosity, pore interconnectivity, and scaffold percolative efficiency (SPE, were simulated by a robust image analysis. Mouse fibroblast cells (L929 were cultured in RPMI for 2 days in the presence of various samples of nanofibrous chitosan/PEO scaffolds. Cell attachments and corresponding mean viability were enhanced from 50% to 110% compared to that belonging to a control even at packed morphologies of scaffolds constituted from pores with nanoscale diameter. To elucidate the correlation between structural characteristics within the depth of the scaffolds’ profile and cell viability, a comparative analysis was proposed. This analysis revealed that larger fiber diameters and pore sizes can enhance cell viability. On the contrary, increasing the other structural elements such as overall porosity and interconnectivity due to a simultaneous reduction in fiber diameter and pore size through the electrospinning process can reduce the viability of cells. In addition, it was found that manipulation of the processing parameters in electrospinning can compensate for the effects of packed morphologies of nanofibrous scaffolds and can thus potentially improve the infiltration and viability of cells.

  13. Porous, one-dimensional and high aspect ratio nanofibric network of cobalt manganese oxide as a high performance material for aqueous and solid-state supercapacitor (2 V)

    Science.gov (United States)

    Bhagwan, Jai; Sivasankaran, V.; Yadav, K. L.; Sharma, Yogesh

    2016-09-01

    Porous nanofibric network of spinel CoMn2O4 (CMO) are fabricated by facile electrospinning process and characterized by XRD, BET, TGA, FTIR, FESEM, TEM, XPS techniques. CMO nanofibers are employed as supercapacitor electrode for first time which exhibits high specific capacitance (Cs) of 320(±5) F g-1 and 270(±5) F g-1 at 1 A g-1 and 5 A g-1, respectively in 1 M H2SO4. CMO nanofibers exhibit excellent cyclability (till 10,000 cycles @ 5 A g-1). To examine practical performance, solid-state symmetric supercapacitor (SSSC) is also fabricated using PVA-H2SO4 as gel electrolyte. The SSSC evinces high energy density of 75 W h kg-1 (comparable to Pb-acid and Ni-MH battery) along with high power density of 2 kW kg-1. Furthermore, a red colored LED (1.8 V @ current 20 mA) was lit for 5 min using single SSSC device supporting its output voltage of 2 V. This high performance of CMO in both aqueous and SSSC is attributed to one dimensional nanofibers consisting of voids/gaps with minimum inter-particle resistance that facilitates smoother transportation of electrons/ions. These voids/gaps in CMO (structural as well as morphological) act as intercalation/de-intercalation sites for extra storage performance, and also works as buffering space to accommodate stress/strain produced while long term cyclings.

  14. Power electronics substrate for direct substrate cooling

    Science.gov (United States)

    Le, Khiet [Mission Viejo, CA; Ward, Terence G [Redondo Beach, CA; Mann, Brooks S [Redondo Beach, CA; Yankoski, Edward P [Corona, CA; Smith, Gregory S [Woodland Hills, CA

    2012-05-01

    Systems and apparatus are provided for power electronics substrates adapted for direct substrate cooling. A power electronics substrate comprises a first surface configured to have electrical circuitry disposed thereon, a second surface, and a plurality of physical features on the second surface. The physical features are configured to promote a turbulent boundary layer in a coolant impinged upon the second surface.

  15. Novel class of collector in electrospinning device for the fabrication of 3D nanofibrous structure for large defect load-bearing tissue engineering application.

    Science.gov (United States)

    Hejazi, Fatemeh; Mirzadeh, Hamid; Contessi, Nicola; Tanzi, Maria Cristina; Faré, Silvia

    2017-05-01

    Adequate porosity, appropriate pore size, and 3D-thick shape are crucial parameters in the design of scaffolds, as they should provide the right space for cell adhesion, spreading, migration, and growth. In this work, a novel design for fabricating a 3D nanostructured scaffold by electrospinning was taken into account. Helical spring-shaped collector was purposely designed and used for electrospinning PCL fibers. Improved morphological properties and more uniform diameter distribution of collected nanofibers on the turns of helical spring-shaped collector are confirmed by SEM analysis. SEM images elaboration showed 3D pores with average diameter of 4 and 5.5 micrometer in x-y plane and z-direction, respectively. Prepared 3D scaffold possessed 99.98% porosity which led to the increased water uptake behavior in PBS at 37°C up to 10 days, and higher degradation rate compared to 2D flat structure. Uniaxial compression test on 3D scaffolds revealed an elastic modulus of 7 MPa and a stiffness of 10(2) MPa, together with very low hysteresis area and residual strain. In vitro cytocompatibility test with MG-63 osteoblast-like cells using AlamarBlue(™) colorimetric assay, indicated a continuous increase in cell viability for the 3D structure over the test duration. SEM observation showed enhanced cells spreading and diffusion into the underneath layers for 3D scaffold. Accelerated calcium deposition in 3D substrate was confirmed by EDX analysis. Obtained morphological, physical, and mechanical properties together with in vitro cytocompatibility results, suggest this novel technique as a proper method for the fabrication of 3D nanofibrous scaffolds for the regeneration of critical-size load bearing defects. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 1535-1548, 2017.

  16. In Vivo Study of Ligament-Bone Healing after Anterior Cruciate Ligament Reconstruction Using Autologous Tendons with Mesenchymal Stem Cells Affinity Peptide Conjugated Electrospun Nanofibrous Scaffold

    Directory of Open Access Journals (Sweden)

    Jingxian Zhu

    2013-01-01

    Full Text Available Electrospinning nanofibrous scaffold was commonly used in tissue regeneration recently. Nanofibers with specific topological characteristics were reported to be able to induce osteogenic differentiation of MSCs. In this in vivo study, autologous tendon grafts with lattice-like nanofibrous scaffold wrapping at two ends of autologous tendon were used to promote early stage of ligament-bone healing after rabbit ACL reconstruction. To utilize native MSCs from bone marrow, an MSCs specific affinity peptide E7 was conjugated to nanofibrous meshes. After 3 months, H-E assessment and specific staining of collagen type I, II, and III showed direct ligament-bone insertion with typical four zones (bone, calcified fibrocartilage, fibrocartilage, and ligament in bioactive scaffold reconstruction group. Diameters of bone tunnel were smaller in nanofibrous scaffold conjugated E7 peptide group than those in control group. The failure load of substitution complex also indicated a stronger ligament-bone insertion healing using bioactive scaffold. In conclusion, lattice-like nanofibrous scaffold with specific MSCs affinity peptide has great potential in promoting early stage of ligament-bone healing after ACL reconstruction.

  17. Silk fibroin/sodium alginate composite nano-fibrous scaffold prepared through thermally induced phase-separation (TIPS) method for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Haiping, E-mail: zhp9810_a@163.com; Liu, Xiaotian, E-mail: xtianliu@126.com; Yang, Mingying, E-mail: yangm@zju.edu.cn; Zhu, Liangjun, E-mail: ljzhu@zju.edu.cn

    2015-10-01

    To mimic the natural fibrous structure of the tissue extracellular matrix, a nano-fibrous silk fibroin (SF)/sodium alginate (SA) composite scaffold was fabricated by a thermally-induced phase-separation method. The effects of SF/SA ratio on the structure and the porosity of the composite scaffolds were examined. Scanning electron microscopy and porosity results showed that the 5SF/1SA and 3SF/1SA scaffolds possessed an excellent nano-fibrous structure and a porosity of more than 90%. Fourier transform infrared, X-ray diffraction, and differential scanning calorimetry results indicated the physical interaction between SF and SA molecules and their good compatibility in the 5SF/1SA and 3SF/1SA scaffolds, whereas they showed less compatibility in the 1SF/1SA scaffold. Cell culture results showed that MG-63 cells can attach and grow well on the surface of the SF/SA scaffolds. The nano-fibrous SF/SA scaffold can be potentially used in tissue engineering. - Highlights: • We fabricate a nano-fibrous silk fibroin (SF)/sodium alginate (SA) composite scaffold. • The scaffold was prepared through a thermally induced phase separation method. • SF molecules are physically interacted with SA molecules. • Good molecular compatibility can be found in 5SF/1SA and 3SF/1SA scaffolds. • The nano-fibrous SF/SA scaffold is biocompatible.

  18. Electrospun nanofibrous SF/P(LLA-CL membrane: a potential substratum for endothelial keratoplasty

    Directory of Open Access Journals (Sweden)

    Chen JZ

    2015-05-01

    Full Text Available Junzhao Chen,1,* Chenxi Yan,1,* Mengyu Zhu,1,* Qinke Yao,1 Chunyi Shao,1 Wenjuan Lu,1 Jing Wang,2 Xiumei Mo,2 Ping Gu,1 Yao Fu,1 Xianqun Fan1 1Department of Ophthalmology, Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, 2Biomaterials and Tissue Engineering Laboratory, College of Chemistry and Chemical Engineering and Biotechnology, Donghua University, Shanghai, People’s Republic of China *These authors contributed equally to this work Background: Cornea transplant technology has progressed markedly in recent decades, allowing surgeons to replace diseased corneal endothelium by a thin lamellar structure. A thin, transparent, biocompatible, tissue-engineered substratum with corneal endothelial cells for endothelial keratoplasty is currently of interest. Electrospinning a nanofibrous structure can simulate the extracellular matrix and have beneficial effects for cell culture. Silk fibroin (SF has good biocompatibility but poor mechanical properties, while poly(L-lactic acid-co-Ɛ-caprolactone (P(LLA-CL has good mechanical properties but poor biocompatibility. Blending SF with P(LLA-CL can maintain the advantages of both these materials and overcome their disadvantages. Blended electrospun nanofibrous membranes may be suitable for regeneration of the corneal endothelium. The aim of this study was to produce a tissue-engineered construct suitable for endothelial keratoplasty.Methods: Five scaffolds containing different SF:P(LLA-CL blended ratios (100:0, 75:25, 50:50, 25:75, 0:100 were manufactured. A human corneal endothelial (B4G12 cell line was cultured on the membranes. Light transmission, speed of cell adherence, cell viability (live-dead test, cell proliferation (Ki-67, BrdU staining, and cell monolayer formation were detected on membranes with the different blended ratios, and expression of some functional genes was also detected by real-time polymerase chain reaction.Results: Different blended ratios of scaffolds

  19. Stiff substrates enhance cultured neuronal network activity.

    Science.gov (United States)

    Zhang, Quan-You; Zhang, Yan-Yan; Xie, Jing; Li, Chen-Xu; Chen, Wei-Yi; Liu, Bai-Lin; Wu, Xiao-an; Li, Shu-Na; Huo, Bo; Jiang, Lin-Hua; Zhao, Hu-Cheng

    2014-08-28

    The mechanical property of extracellular matrix and cell-supporting substrates is known to modulate neuronal growth, differentiation, extension and branching. Here we show that substrate stiffness is an important microenvironmental cue, to which mouse hippocampal neurons respond and integrate into synapse formation and transmission in cultured neuronal network. Hippocampal neurons were cultured on polydimethylsiloxane substrates fabricated to have similar surface properties but a 10-fold difference in Young's modulus. Voltage-gated Ca(2+) channel currents determined by patch-clamp recording were greater in neurons on stiff substrates than on soft substrates. Ca(2+) oscillations in cultured neuronal network monitored using time-lapse single cell imaging increased in both amplitude and frequency among neurons on stiff substrates. Consistently, synaptic connectivity recorded by paired recording was enhanced between neurons on stiff substrates. Furthermore, spontaneous excitatory postsynaptic activity became greater and more frequent in neurons on stiff substrates. Evoked excitatory transmitter release and excitatory postsynaptic currents also were heightened at synapses between neurons on stiff substrates. Taken together, our results provide compelling evidence to show that substrate stiffness is an important biophysical factor modulating synapse connectivity and transmission in cultured hippocampal neuronal network. Such information is useful in designing instructive scaffolds or supporting substrates for neural tissue engineering.

  20. A living thick nanofibrous implant bifunctionalized with active growth factor and stem cells for bone regeneration

    Directory of Open Access Journals (Sweden)

    Eap S

    2015-02-01

    Full Text Available Sandy Eap,1,2,* Laetitia Keller,1–3,* Jessica Schiavi,1,2 Olivier Huck,1,2 Leandro Jacomine,4 Florence Fioretti,1,2 Christian Gauthier,4 Victor Sebastian,1,3,5 Pascale Schwinté,1,2 Nadia Benkirane-Jessel1,21INSERM, UMR 1109, Osteoarticular and Dental Regenerative Nanomedicine Laboratory, FMTS, Faculté de Médecine, Strasbourg, France; 2Faculté de Chirurgie Dentaire, Université de Strasbourg, Strasbourg, France; 3Department of Chemical Engineering, Aragon Nanoscience Institute, University of Zaragoza, Zaragoza, Spain; 4CNRS (National Center for Scientific Research, ICS (Charles Sadron Institute, Strasbourg, France; 5Networking Research Center of Bioengineering, Biomaterials and Nanomedicine, Zaragoza, Spain*These authors contributed equally to this workAbstract: New-generation implants focus on robust, durable, and rapid tissue regeneration to shorten recovery times and decrease risks of postoperative complications for patients. Herein, we describe a new-generation thick nanofibrous implant functionalized with active containers of growth factors and stem cells for regenerative nanomedicine. A thick electrospun poly(ε-caprolactone nanofibrous implant (from 700 µm to 1 cm thick was functionalized with chitosan and bone morphogenetic protein BMP-7 as growth factor using layer-by-layer technology, producing fish scale-like chitosan/BMP-7 nanoreservoirs. This extracellular matrix-mimicking scaffold enabled in vitro colonization and bone regeneration by human primary osteoblasts, as shown by expression of osteocalcin, osteopontin, and bone sialoprotein (BSPII, 21 days after seeding. In vivo implantation in mouse calvaria defects showed significantly more newly mineralized extracellular matrix in the functionalized implant compared to a bare scaffold after 30 days’ implantation, as shown by histological scanning electron microscopy/energy dispersive X-ray microscopy study and calcein injection. We have as well bifunctionalized our BMP-7

  1. A review of polymer nanofibres by electrospinning and their application in oil-water separation for cleaning up marine oil spills.

    Science.gov (United States)

    Sarbatly, Rosalam; Krishnaiah, Duduku; Kamin, Zykamilia

    2016-05-15

    The growths of oil and gas exploration and production activities have increased environmental problems, such as oil spillage and the resulting pollution. The study of the methods for cleaning up oil spills is a critical issue to protect the environment. Various techniques are available to contain oil spills, but they are typically time consuming, energy inefficient and create secondary pollution. The use of a sorbent, such as a nanofibre sorbent, is a technique for controlling oil spills because of its good physical and oil sorption properties. This review discusses about the application of nanofibre sorbent for oil removal from water and its current developments. With their unique physical and mechanical properties coupled with their very high surface area and small pore sizes, nanofibre sorbents are alternative materials for cleaning up oil spills.

  2. Simultaneous dual syringe electrospinning system using benign solvent to fabricate nanofibrous P(3HB-co-4HB)/collagen peptides construct as potential leave-on wound dressing

    Energy Technology Data Exchange (ETDEWEB)

    Vigneswari, S. [Malaysian Institute of Pharmaceuticals and Nutraceuticals, NIBM, MOSTI, 11700 Penang (Malaysia); Institute of Marine Biotechnology, Universiti Malaysia Terengganu, 21030 Kuala Terengganu (Malaysia); Murugaiyah, V. [School of Pharmaceutical Sciences, Universiti Sains Malaysia, 11700 Penang (Malaysia); Kaur, G. [Institute of Research in Molecular Medicine, Universiti Sains Malaysia, 11700 Penang (Malaysia); Abdul Khalil, H.P.S. [School of Industrial Technology, Universiti Sains Malaysia, 11700 Penang (Malaysia); Amirul, A.A., E-mail: amirul@usm.my [Malaysian Institute of Pharmaceuticals and Nutraceuticals, NIBM, MOSTI, 11700 Penang (Malaysia); School of Biological Sciences, Universiti Sains Malaysia, 11800 Penang (Malaysia); Centre of Chemical Biology, Universiti Sains Malaysia, 11900 Penang (Malaysia)

    2016-09-01

    The main focus of this study is the incorporation of collagen peptides to fabricate P(3-hydroxybutyrate-co-4-hydroxybutyrate) [P(3HB-co-4HB)] nano-fiber construct to further enhance surface wettability and support cell growth while harbouring desired properties for biodegradable wound dressing. Simultaneous electrospinning of nanofiber P(3HB-co-4HB)/collagen peptides construct was carried out using dual syringe system. The wettability of the constructs increased with the increase in 4HB molar fraction from 20 mol% 4HB [53.2°], P(3HB-co-35 mol%4HB)[48.9°], P(3HB-co-50 mol%4HB)[44.5°] and P(3HB-co-82 mol%4HB) [37.7°]. In vitro study carried out using mouse fibroblast cells (L929) grown on nanofiber P(3HB-co-4HB)/collagen peptides construct showed an increase in cell proliferation. In vivo study using animal model (Sprague Dawley rats) showed that nanofibrous P(3HB-co-4HB)/collagen peptides construct had a significant effect on wound contractions with the highest percentage of wound closure of 79%. Hence, P(3HB-co-4HB)/collagen peptides construct suitable for wound dressing have been developed using nano-fabrication technique. - Highlights: • Nano-fiber construct to enhance surface wettability and cell growth, harbouring desired properties as biodegradable wound dressing. • Simultaneous electrospinning of nanofiber P(3HB-co-4HB)/collagen construct using dual syringe system. • Nanofibrous construct accelerated wound healing with efficient cellular organization.

  3. In situ real-time imaging of self-sorted supramolecular nanofibres

    Science.gov (United States)

    Onogi, Shoji; Shigemitsu, Hajime; Yoshii, Tatsuyuki; Tanida, Tatsuya; Ikeda, Masato; Kubota, Ryou; Hamachi, Itaru

    2016-08-01

    Self-sorted supramolecular nanofibres—a multicomponent system that consists of several types of fibre, each composed of distinct building units—play a crucial role in complex, well-organized systems with sophisticated functions, such as living cells. Designing and controlling self-sorting events in synthetic materials and understanding their structures and dynamics in detail are important elements in developing functional artificial systems. Here, we describe the in situ real-time imaging of self-sorted supramolecular nanofibre hydrogels consisting of a peptide gelator and an amphiphilic phosphate. The use of appropriate fluorescent probes enabled the visualization of self-sorted fibres entangled in two and three dimensions through confocal laser scanning microscopy and super-resolution imaging, with 80 nm resolution. In situ time-lapse imaging showed that the two types of fibre have different formation rates and that their respective physicochemical properties remain intact in the gel. Moreover, we directly visualized stochastic non-synchronous fibre formation and observed a cooperative mechanism.

  4. Electrospun Chitosan/Polyethylene Oxide Nanofibrous Scaffolds with Potential Antibacterial Wound Dressing Applications

    Directory of Open Access Journals (Sweden)

    Tony T. Yuan

    2016-01-01

    Full Text Available Electrospinning is a simple and versatile technique for the fabrication of nonwoven fibrous materials for biomedical applications. In the present study, chitosan (CS and polyethylene oxide (PEO nanofibrous scaffolds were successfully prepared using three different CS/PEO mass ratios and then evaluated for their physical, chemical, and biological characteristics. Scaffold morphologies were observed by scanning electron microscopy, which showed decreasing fiber diameters with increasing CS content. Higher CS concentrations also correlated with increased tensile strength and decreased elasticity of the scaffold. Degradation studies demonstrated that PEO was solubilized from the scaffold within the first six hours, followed by CS. This profile was unaffected by changes in the CS/PEO ratio or the pH of the media. Only the 2 : 1 CS/PEO scaffold demonstrated superior inhibition of both growth and attachment of Staphylococcus aureus. Finally, all scaffolds exhibited little impact on the proliferation of murine fibroblast monolayers. These data demonstrate that the 2 : 1 CS/PEO scaffold is a promising candidate for wound dressing applications due to its excellent antibacterial characteristics and biocompatibility.

  5. Thin-film Nanofibrous Composite Membranes Containing Cellulose or Chitin Barrier Layers Fabricated by Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    H Ma; B Hsiao; B Chu

    2011-12-31

    The barrier layer of high-flux ultrafiltration (UF) thin-film nanofibrous composite (TFNC) membranes for purification of wastewater (e.g., bilge water) have been prepared by using cellulose, chitin, and a cellulose-chitin blend, regenerated from an ionic liquid. The structures and properties of regenerated cellulose, chitin, and a cellulose-chitin blend were analyzed with thermogravimetric analysis (TGA) and wide-angle X-ray diffraction (WAXD). The surface morphology, pore size and pore size distribution of TFNC membranes were determined by SEM images and molecular weight cut-off (MWCO) methods. An oil/water emulsion, a model of bilge water, was used as the feed solution, and the permeation flux and rejection ratio of the membranes were investigated. TFNC membranes based on the cellulose-chitin blend exhibited 10 times higher permeation flux when compared with a commercial UF membrane (PAN10, Sepro) with a similar rejection ratio after filtration over a time period of up to 100 h, implying the practical feasibility of such membranes for UF applications.

  6. Characterisation of electrospun gelatine nanofibres encapsulated with Moringa oleifera bioactive extract.

    Science.gov (United States)

    Hani, Norziah M; Torkamani, Amir E; Azarian, Mohammad H; Mahmood, Kamil Wa; Ngalim, Siti Hawa

    2017-08-01

    Drumstick (Moringa oleifera) leaves have been used as a folk herbal medicine across many cultures since ancient times. This is most probably due to presence of phytochemicals possessing antioxidant properties, which could retard oxidative stress, and their degenerative effect. The current study deals with nanoencapsulation of Moringa oleifera (MO) leaf ethanolic extract within fish sourced gelatine matrix using electrospinning technique. The total phenolic and flavonoid content, radical scavenging (IC50 ) and metal reducing properties were 67.0 ± 2.5 mg GAE g(-1) sample 32.0 ± 0.5 mg QE g(-1) extract, 0.08 ± 0.01 mg mL(-1) and 510 ± 10 µmol eq Fe(II) g(-1) extract, respectively. Morphological and spectroscopic analysis of the fibre mats confirmed successful nanoencapsulation of MO extract within defect free nanofibres via electrospinning process. The percentage encapsulation efficiency (EE) was between 80% and 85%. Furthermore, thermal stability of encapsulated fibres, especially at 3% and 5% of core loading content, was significantly improved. Toxicological analysis revealed that the extract in its original and encapsulated form was safe for oral consumption. Overall, the present study showed the potential of ambient temperature electrospinning process as a safe nanoencapsulation method, where MO extract retained its antioxidative capacities. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  7. A regenerable oxide-based H2S adsorbent with nanofibrous morphology.

    Science.gov (United States)

    Behl, Mayank; Yeom, Junghoon; Lineberry, Quentin; Jain, Prashant K; Shannon, Mark A

    2012-12-01

    Hydrogen sulphide is found in raw fuels such as natural gas and coal/biomass-derived syngas. It is poisonous to catalysts and corrosive to metals and therefore needs to be removed. This is often achieved using metal oxides as reactive adsorbents, but metal oxides perform poorly when subjected to repeated cycles of sulphidation and re-oxidation as a result of complex structural and chemical changes. Here, we show that Zn-Ti-O-based adsorbents with nanofibrous morphology can sustain their initial reactivity and sulphur removal capacity over multiple regeneration cycles. These nanostructured sorbents offer rapid reaction rates that overcome the gas-transport limitations of conventional pellet-based sorbents and allow all of the material to be used efficiently. Regeneration can be carried out at the same temperature as the sulphidation step because of the higher reactivity, which prevents sorbent deterioration and reduces energy use. The efficient regeneration of the adsorbent is also aided by structural features such as the growth of hierarchical nanostructures and preferential stabilization of a wurtzite phase in the sulphidation product.

  8. Encapsulation of volatiles in nanofibrous polysaccharide membranes for humidity-triggered release.

    Science.gov (United States)

    Mascheroni, Erika; Fuenmayor, Carlos Alberto; Cosio, Maria Stella; Di Silvestro, Giuseppe; Piergiovanni, Luciano; Mannino, Saverio; Schiraldi, Alberto

    2013-10-15

    A single-step electrospinning process will be applied to a blend of edible carbohydrate polymers (pullulan and β-cyclodextrin) to encapsulate bioactive aroma compounds and allow a humidity-triggered release. The encapsulation is rapid and efficient and the final product is an active nanofibrous membrane that can be directly used for food or active packaging applications. The membrane hosts small and homogeneously dispersed crystals of cyclodextrin-aroma complexes which are formed during the electrospinning. With this type of structure, the release of aroma compound is negligible at ambient conditions (23 °C and 55% UR) even at high temperature (up to 230 °C), and it occurs beyond a given relative humidity threshold (90%), useful for food packaging applications. The mass fraction of free aroma released is directly related to the water activity of the system, namely, φ=aW(n)/(aW(n)+Kapp) explaining the observed key role played by the relative humidity on the release of the aroma compounds.

  9. Synthesis of carbon nanofibres from waste chicken fat for field electron emission applications

    Energy Technology Data Exchange (ETDEWEB)

    Suriani, A.B., E-mail: absuriani@yahoo.com [Nanotechnology Research Centre, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, Tanjung Malim, Perak 35900 (Malaysia); Department of Physics, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, Tanjung Malim, Perak 35900 (Malaysia); Dalila, A.R. [Nanotechnology Research Centre, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, Tanjung Malim, Perak 35900 (Malaysia); Department of Physics, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, Tanjung Malim, Perak 35900 (Malaysia); Mohamed, A.; Isa, I.M.; Kamari, A.; Hashim, N. [Nanotechnology Research Centre, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, Tanjung Malim, Perak 35900 (Malaysia); Department of Chemistry, Faculty of Science and Mathematics, Universiti Pendidikan Sultan Idris, Tanjung Malim, Perak 35900 (Malaysia); Soga, T.; Tanemura, M. [Department of Frontier Materials, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan)

    2015-10-15

    Highlights: • Waste chicken fat is used as a starting material to produce CNFs via TCVD method. • High heating rate applied resulted in aggregation of catalyst particles. • Aggregated catalyst produced sea urchin-like CNFs with amorphous nature. • The as-grown CNFs presented a potential for field electron emission applications. - Abstract: Carbon nanofibres (CNFs) with sea urchin-like morphology were synthesised from waste chicken fat precursor via catalytic thermal chemical vapour deposition method at 750 °C. The CNFs showed amorphous structures under high-resolution transmission electron microscopy, micro-Raman spectroscopy and X-ray diffraction examination. X-ray photoelectron spectroscopy analysis confirmed that the core of the sea urchin-like CNFs was composed of Fe{sub 3}C formed within the first 20 min of synthesis time. The growth of amorphous CNFs from agglomerated Fe{sub 3}C particles was favourable due to the high heating rate applied during the synthesis. Field electron emission examination of the CNFs indicated turn-on and threshold field values of 5.4 and 6.6 V μm{sup −1} at current density of 1 and 10 μA cm{sup −2}, respectively. This study demonstrates that waste chicken fat, a low-cost and readily available resource, can be used as an inexpensive carbon source for the production of CNFs with a potential application in field electron emitters.

  10. In vivo bone regeneration using tubular perfusion system bioreactor cultured nanofibrous scaffolds.

    Science.gov (United States)

    Yeatts, Andrew B; Both, Sanne K; Yang, Wanxun; Alghamdi, Hamdan S; Yang, Fang; Fisher, John P; Jansen, John A

    2014-01-01

    The use of bioreactors for the in vitro culture of constructs for bone tissue engineering has become prevalent as these systems may improve the growth and differentiation of a cultured cell population. Here we utilize a tubular perfusion system (TPS) bioreactor for the in vitro culture of human mesenchymal stem cells (hMSCs) and implant the cultured constructs into rat femoral condyle defects. Using nanofibrous electrospun poly(lactic-co-glycolic acid)/poly(ε-caprolactone) scaffolds, hMSCs were cultured for 10 days in vitro in the TPS bioreactor with cellular and acellular scaffolds cultured statically for 10 days as a control. After 3 and 6 weeks of in vivo culture, explants were removed and subjected to histomorphometric analysis. Results indicated more rapid bone regeneration in defects implanted with bioreactor cultured scaffolds with a new bone area of 1.23 ± 0.35 mm(2) at 21 days compared to 0.99 ± 0.43 mm(2) and 0.50 ± 0.29 mm(2) in defects implanted with statically cultured scaffolds and acellular scaffolds, respectively. At the 21 day timepoint, statistical differences (pbioreactor to improve bone tissue regeneration and highlights the benefits of utilizing perfusion bioreactor systems to culture MSCs for bone tissue engineering.

  11. Two-Dimensional Simulation of Electrospun Nanofibrous Structures: Connection of Experimental and Simulated Results

    Directory of Open Access Journals (Sweden)

    Panu Danwanichakul

    2014-01-01

    Full Text Available Nanofibrous mats were obtained from electrospinning Nylon-6 solutions with concentrations of 30 and 35 wt% and were tested for filtration of polystyrene particles in suspension. Some experimental results were compared with the simulated ones. In the simulation, the two-dimensional structures were constructed by randomly depositing a nanofiber, which was assumed as an ellipse with an aspect ratio of 100, one by one. The nanofiber size is assumed to be polydisperse. The results showed that simulated configurations resembled real nanofibers with polydisperse diameters. Fibers from higher solution concentration were larger, resulting in larger pore size, which was confirmed with simulations. Varying the size distribution around the same average value did not make any difference to the surface coverage but it affected 2D pore areas for the systems at low fiber density. In addition, the probability for a particle to pass through the porous structure was less when the fiber density was higher and the particle diameter was larger, which was consistent with the filtration test. Lastly, water flux measurement could yield the void volume fraction as well as the volume-averaged pore diameter, which was found to be greater than the averaged 2D pore diameter from SEM micrographs by the quantity related to the fiber size.

  12. Multi-functional electrospun nanofibres for advances in tissue regeneration, energy conversion & storage, and water treatment.

    Science.gov (United States)

    Peng, Shengjie; Jin, Guorui; Li, Linlin; Li, Kai; Srinivasan, Madhavi; Ramakrishna, Seeram; Chen, Jun

    2016-03-07

    Tissue regeneration, energy conversion & storage, and water treatment are some of the most critical challenges facing humanity in the 21st century. In order to address such challenges, one-dimensional (1D) materials are projected to play a key role in developing emerging solutions for the increasingly complex problems. Eletrospinning technology has been demonstrated to be a simple, versatile, and cost-effective method in fabricating a rich variety of materials with 1D nanostructures. These include polymers, composites, and inorganic materials with unique chemical and physical properties. In this tutorial review, we first give a brief introduction to electrospun materials with a special emphasis on the design, fabrication, and modification of 1D functional materials. Adopting the perspective of chemists and materials scientists, we then focus on the recent significant progress made in the domains of tissue regeneration (e.g., skin, nerve, heart and bone) and conversion & storage of clean energy (e.g., solar cells, fuel cells, batteries, and supercapacitors), where nanofibres have been used as active nanomaterials. Furthermore, this review's scope also includes the advances in the use of electrospun materials for the removal of heavy metal ions, organic pollutants, gas and bacteria in water treatment applications. Finally a conclusion and perspective is provided, in which we discuss the remaining challenges for 1D electrospun nanomaterials in tissue regeneration, energy conversion & storage, and water treatment.

  13. π-Conjugated polymer anisotropic organogel nanofibrous assemblies for thermoresponsive photonic switches.

    Science.gov (United States)

    Narasimha, Karnati; Jayakannan, Manickam

    2014-11-12

    The present work demonstrates one of the first examples of π-conjugated photonic switches (or photonic wave plates) based on the tailor-made π-conjugated polymer anisotropic organogel. New semicrystalline segmented π-conjugated polymers are designed with rigid aromatic oligophenylenevinylene π-core and flexible alkyl chain along the polymer backbone. These polymers are found to be self-assembled as semicrystalline or amorphous with respect to the number of carbon atoms in the alkyl units. These semicrystalline polymers produce organogels having nanofibrous morphology of 20 nm thickness with length up to 5 μm. The polymer organogel is aligned in a narrow glass capillary, and this anisotropic gel device is further demonstrated as photonic switches. The glass capillary device behaves as typical λ/4 photonic wave plates upon the illumination of the plane polarized light. The λ/4 photonic switching ability is found to be maximum at θ = 45° angle under the cross polarizers. The orthogonal arrangements of the gel capillaries produce dark and bright spots as on-and-off optical switches. Thermoreversibility of the polymer organogel (also its xerogel) was exploited to construct thermoresponsive photonic switches for the temperature window starting from 25 to 160 °C. The organic photonic switch concept can be adapted to large number of other π-conjugated materials for optical communication and storage.

  14. Mechanics of oriented electrospun nanofibrous scaffolds for annulus fibrosus tissue engineering.

    Science.gov (United States)

    Nerurkar, Nandan L; Elliott, Dawn M; Mauck, Robert L

    2007-08-01

    Engineering a functional replacement for the annulus fibrosus (AF) of the intervertebral disc is contingent upon recapitulation of AF structure, composition, and mechanical properties. In this study, we propose a new paradigm for AF tissue engineering that focuses on the reconstitution of anatomic fiber architecture and uses constitutive modeling to evaluate construct function. A modified electrospinning technique was utilized to generate aligned nanofibrous polymer scaffolds for engineering the basic functional unit of the AF, a single lamella. Scaffolds were tested in uniaxial tension at multiple fiber orientations, demonstrating a nonlinear dependence of modulus on fiber angle that mimicked the nonlinearity and anisotropy of native AF. A homogenization model previously applied to native AF successfully described scaffold mechanical response, and parametric studies demonstrated that nonfibrillar matrix, along with fiber connectivity, are key contributors to tensile mechanics for engineered AF. We demonstrated that AF cells orient themselves along the aligned scaffolds and deposit matrix that contributes to construct mechanics under loading conditions relevant to the in vivo environment. The homogenization model was applied to cell-seeded constructs and provided quantitative measures for the evolution of matrix and interfibrillar interactions. Finally, the model demonstrated that at fiber angles of the AF (28 degrees -44 degrees ), engineered material behaved much like native tissue, suggesting that engineered constructs replicate the physiologic behavior of the single AF lamella. Constitutive modeling provides a powerful tool for analysis of engineered AF neo-tissue and native AF tissue alike, highlighting key mechanical design criteria for functional AF tissue engineering.

  15. In Vivo Bone Regeneration Using Tubular Perfusion System Bioreactor Cultured Nanofibrous Scaffolds

    Science.gov (United States)

    Yeatts, Andrew B.; Both, Sanne K.; Yang, Wanxun; Alghamdi, Hamdan S.; Yang, Fang; Jansen, John A.

    2014-01-01

    The use of bioreactors for the in vitro culture of constructs for bone tissue engineering has become prevalent as these systems may improve the growth and differentiation of a cultured cell population. Here we utilize a tubular perfusion system (TPS) bioreactor for the in vitro culture of human mesenchymal stem cells (hMSCs) and implant the cultured constructs into rat femoral condyle defects. Using nanofibrous electrospun poly(lactic-co-glycolic acid)/poly(ɛ-caprolactone) scaffolds, hMSCs were cultured for 10 days in vitro in the TPS bioreactor with cellular and acellular scaffolds cultured statically for 10 days as a control. After 3 and 6 weeks of in vivo culture, explants were removed and subjected to histomorphometric analysis. Results indicated more rapid bone regeneration in defects implanted with bioreactor cultured scaffolds with a new bone area of 1.23±0.35 mm2 at 21 days compared to 0.99±0.43 mm2 and 0.50±0.29 mm2 in defects implanted with statically cultured scaffolds and acellular scaffolds, respectively. At the 21 day timepoint, statistical differences (pbioreactor to improve bone tissue regeneration and highlights the benefits of utilizing perfusion bioreactor systems to culture MSCs for bone tissue engineering. PMID:23865551

  16. Chondrogenic differentiation of menstrual blood-derived stem cells on nanofibrous scaffolds.

    Science.gov (United States)

    Kazemnejad, Somaieh; Zarnani, Amir-Hassan; Khanmohammadi, Manijeh; Mobini, Sahba

    2013-01-01

    Cartilage tissue engineering is a promising technology to restore and repair cartilage lesions in the body. In recent years, significant advances have been made using stem cells as a cell source for clinical goals of cartilage tissue engineering. Menstrual blood-derived stem cells (MenSCs) is a novel population of stem cells that demonstrate the potential and differentiate into a wide range of tissues including the chondrogenic lineage. Incorporation of cell culture with extracellular matrix (ECM) like substratum plays an important role in cartilage tissue regeneration by providing attachment sites as well as bioactive signals for cells to grow and differentiate into chondrogenic lineage. The electrospun nanofibers are a class of polymer-based biomaterials that have been extensively utilized in tissue engineering as ECM-like scaffold. This chapter discusses potential of electrospun nanofibers for cell-based cartilage tissue engineering and presents detailed protocols on immunophenotyping characterization and chondrogenic differentiation of MenSCs seeded in poly-ε-caprolactone (PCL) nanofibers. The isolated MenSCs are characterized using flow cytometry, seeded on the nanofibers, imaged using scanning electron microscopy, and subsequently differentiated into chondrogenic lineage in culture medium containing specific growth factors and cytokines. Immunofluorescence and alcian blue staining are used to evaluate the development of seeded MenSCs in PCL nanofibrous scaffold into chondrogenic lineage.

  17. Colour-producing [beta]-keratin nanofibres in blue penguin (Eudyptula minor) feathers

    Energy Technology Data Exchange (ETDEWEB)

    D; Alba, Liliana; Saranathan, Vinodkumar; Clarke, Julia A.; Vinther, Jakob A.; Prum, Richard O.; Shawkey, Matthew D. (Yale); (Akron); (Texas)

    2012-03-26

    The colours of living organisms are produced by the differential absorption of light by pigments (e.g. carotenoids, melanins) and/or by the physical interactions of light with biological nanostructures, referred to as structural colours. Only two fundamental morphologies of non-iridescent nanostructures are known in feathers, and recent work has proposed that they self-assemble by intracellular phase separation processes. Here, we report a new biophotonic nanostructure in the non-iridescent blue feather barbs of blue penguins (Eudyptula minor) composed of parallel {beta}-keratin nanofibres organized into densely packed bundles. Synchrotron small angle X-ray scattering and two-dimensional Fourier analysis of electron micrographs of the barb nanostructure revealed short-range order in the organization of fibres at the appropriate size scale needed to produce the observed colour by coherent scattering. These two-dimensional quasi-ordered penguin nanostructures are convergent with similar arrays of parallel collagen fibres in avian and mammalian skin, but constitute a novel morphology for feathers. The identification of a new class of {beta}-keratin nanostructures adds significantly to the known mechanisms of colour production in birds and suggests additional complexity in their self-assembly.

  18. A comparative study on properties of micro and nanopapers produced from cellulose and cellulose nanofibres.

    Science.gov (United States)

    Mtibe, A; Linganiso, Linda Z; Mathew, Aji P; Oksman, K; John, Maya J; Anandjiwala, Rajesh D

    2015-03-15

    Cellulose nanocrystals (CNCs) and cellulose nanofibres (CNFs) were successfully extracted from cellulose obtained from maize stalk residues. A variety of techniques, such as Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were used for characterization and the experimental results showed that lignin and hemicellulose were removed to a greater extent by following the chemical methods. Atomic force microscopy (AFM) results confirmed that the diameters of CNCs and CNFs were ranging from 3 to 7 nm and 4 to 10nm, respectively, with their lengths in micro scale. CNCs suspension showed a flow of birefringence, however, the same was not observed in the case of suspension containing CNFs. XRD analysis confirmed that CNCs had high crystallinity index in comparison to cellulose and CNFs. Nanopapers were prepared from CNCs and CNFs by solvent evaporation method. Micropapers were also prepared from cellulose pulp by the same