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    Electrospun polyethersolfone nanofibrous membrane as novel platform for protein immobilization in microfluidic systems

    , Article Journal of Biomedical Materials Research - Part B Applied Biomaterials ; 2017 ; 15524973 (ISSN) Mahmoudifard, M ; Vossoughi, M ; Soudi, S ; Soleimani, M ; Sharif University of Technology
    John Wiley and Sons Inc  2017
    Abstract
    In the present study, the feasibility of electrospun polyethersolfone (PES) nanofibrous membrane as the solid substrate for microfluidic based immunoassays to enhance the density of immobilized antibody on the surface of membrane was assessed. Conversely, the efficacy of antibody immobilization was compared by two different strategies as 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC)/N-Hydroxysuccinimide (NHS) coupling chemistry and hydrophobic interaction. Compared to conventional immunoassays carried out in plates or gels, microfluidic based immunoassays grant a lot of advantages such as a consumption of little samples and reagents, shorter analysis time, and higher efficiency.... 

    PVDF composite nanofibers applications

    , Article Heliyon ; Volume 8, Issue 11 , 2022 ; 24058440 (ISSN) Aghayari, S ; Sharif University of Technology
    Elsevier Ltd  2022
    Abstract
    Polyvinylidene fluoride (PVDF) has special piezo/pyro/ferroelectric, flexibility, low weight, biocompatibility, economical, good chemical/thermal, and high mechanical properties, such as excellent nontoxic fiber/film formation. It has polar and nonpolar phases of α, β, γ, ε, and δ, in which the nonpolar α phase is the most stable one. However, the β phase is the best because it has good piezo/pyro/ferroelectric properties. Copolymers are attractive due to their low weight, nontoxic, chemical acid resistance, flexibility, and ease of processing. These aspects result in their applications in many fields. They are used for piezoelectric nanogenerators, cooling/heating sensors, electronic... 

    Recent Developments of Electrospinning-Based Photocatalysts in Degradation of Organic Pollutants: Principles and Strategies

    , Article ACS Omega ; Volume 7, Issue 50 , 2022 , Pages 45867-45881 ; 24701343 (ISSN) Samadi, M ; Moshfegh, A. Z ; Sharif University of Technology
    American Chemical Society  2022
    Abstract
    Electrospinning is a simple and cheap process for forming one-dimensional (1D) nanofibers with controllable size, morphology, and chemistry. Besides these, the ultrahigh surface area with industrialization capability has attracted extensive interest in the research community. On the other hand, a photocatalytic process is a promising method for degrading organic pollutants that cannot be removed by conventional wastewater treatment. This review focuses on the recent progress of electrospun nanofibers for the photocatalytic degradation of water pollutants. The linkage between the electrospinning technique and the photocatalytic process is classified into two main categories: (1) polymeric... 

    Preparation and characterization of PVDF/Starch nanocomposite nanofibers using electrospinning method

    , Article Materials Today: Proceedings, 2 May 2017 through 3 May 2017 ; Volume 5, Issue 7 , 2018 , Pages 15613-15619 ; 22147853 (ISSN) Amini, M ; Haddadi, A ; Ghaderi, S ; Ramazani, A ; Ansarizadeh, M. H ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    In this study, poly (vinylidene fluoride) PVDF/Starch nanofibers with a great potential for tissue engineering applications have been investigated. The electrospun nanofibers were formed by the electrospinning of the PVDF/Starch solutions in various ratios of PVDF to Starch. Characterizations of PVDF/Starch nanofiber were performed using rheometric mechanical spectroscopy (RMS), field emission scanning electron microscope (FE-SEM) and tensile test. The results showed that the addition of more Starch into the PVDF solution increased the viscosity of the prepared PVDF/Starch solutions. In addition, the mechanical properties of PVDF enhanced in the presence of Starch due to the higher... 

    Fabrication and characterization of electrospun poly-L-lactide/gelatin graded tubular scaffolds: Toward a new design for performance enhancement in vascular tissue engineering

    , Article Progress in Natural Science: Materials International ; Volume 25, Issue 5 , October , 2015 , Pages 405–413 ; 10020071 (ISSN) Yazdanpanah, A ; Tahmasbi, M ; Amoabediny, G ; Nourmohammadi, J ; Moztarzadeh, F ; Mozafari, M ; Sharif University of Technology
    Elsevier  2015
    Abstract
    In this study, a new design of graded tubular scaffolds have been developed for the performance enhancement in vascular tissue engineering. The graded poly-L-lactide (PLLA) and gelatin fibrous scaffolds produced by electrospining were then characterized. The morphology, degradability, porosity, pore size and mechanical properties of four tubular scaffolds (graded PLLA/gelatin, layered PLLA/gelatin, PLLA and gelatin scaffolds) have been investigated. The tensile tests demonstrated that the mechanical strength and also the estimated burst pressure of the graded scaffolds were significantly increased in comparison with the layered and gelatin scaffolds. This new design, resulting in an increase... 

    Different buckling regimes in direct electrospinning: A comparative approach to rope buckling

    , Article Journal of Polymer Science, Part B: Polymer Physics ; Volume 54, Issue 4 , 2016 , Pages 451-456 ; 08876266 (ISSN) Shariatpanahi, S. P ; Etesami, Z ; Iraji Zad, A ; Bonn, D ; Ejtehadi, M. R ; Sharif University of Technology
    John Wiley and Sons Inc  2016
    Abstract
    Understanding the dynamics of direct electrospinning is the key to control fiber morphologies that are critical for the development of new electrospinning methods and novel materials. Here, we propose the theory for direct electrospinning based on theories for (liquid) "rope coiling" and experimentally test it. For the experiments, the buckling of microscale liquid ropes formed from polymer solutions is studied systematically using three different electrospinning setups and for different polymer concentrations. We show that different buckling regimes exist, whose dynamics are governed by an interplay of electrical, inertial, and viscous forces, and that three different buckling regimes... 

    Antimicrobial wound dressing containing silver sulfadiazine with high biocompatibility: In vitro study

    , Article Artificial Organs ; Volume 40, Issue 8 , 2016 , Pages 765-773 ; 0160564X (ISSN) Mohseni, M ; Shamloo, A ; Aghababaei, Z ; Vossoughi, M ; Moravvej, H ; Sharif University of Technology
    Blackwell Publishing Inc 
    Abstract
    Many patients all over the world suffer from acute wounds caused by traumas or burns. In most crucial cases, skin regeneration cannot be promoted spontaneously, and skin grafts are applied as the main treatment. However, this therapy has some drawbacks which motivate researchers to develop wound dressings. In this study, electrospun mats consisting of polycaprolactone (PCL) and polyvinyl alcohol (PVA) incorporated with silver sulfadiazine (SSD) are proposed to be used as antimicrobial wound dressings with the capability of cell seeding. Various amounts of SSD were loaded into PVA nanofibers, and the effects of SSD particles on the morphological characteristics of nanofibers, mechanical... 

    Synthesis and characterization of ZnO/g-C3N4 hybrid nanofibers photocatalyst for the removal of organic pollutants from water

    , Article Iranian Journal of Physics Research ; Volume 20, Issue 2 , 2020 , Pages 273-280 Naseri, A ; Samadi, M ; Pourjavadi, A ; Moshfegh, A ; Sharif University of Technology
    Isfahan University of Technology  2020
    Abstract
    ZnO/gC 3 N 4 hybrid nanofibers containing different concentrations of gC 3 N 4 nanosheets were prepared using electrospinning technique; this was followed by annealing at 460 forC for one hour in a box furnace. Based on scanning electron microscopy (SEM) image analysis, the mean diameter of the nanofibers was measured to be ~ 55 nm. Fourier transform infrared (FTIR) spectroscopy confirmed the presence of ZnO and gC 3 N 4 in the prepared nanofibers. The photocatalytic activity of the nanofibers was examined under UV photoirradiation, showing that the ZCN0.5 nanofibers containing 0.5 wt% of gC 3 N 4exhibited the highest performance, as compared to other photocatalysts. The observed improvement... 

    Experimental Investigation of Biodiesel Production from Oils by Transesterification Method Catalyzed by Nano-heterogeneous Catalysts

    , M.Sc. Thesis Sharif University of Technology Talebi, Soroush (Author) ;
    Abstract
    Today polyolefin definitely is one of the most applicable polymers in the world. One of these polymers is ultra-high molecular weight polyethylene. Being applicable in a number of high-tech industries such as military service, battery separators, and other areas, expands the usage of these polymers. Electrospinning is one of the molding methods in order to synthesize fiber polymers. Using this method, a great deal of polymer fibers have been prepared. It is worth noting that the device used for olefins should have temperature control and temperature increase ability. The electrospinning device with the temperature control has not been built in the country; therefore, this device has been... 

    Micro helical polymeric structures produced by variable voltage direct electrospinning

    , Article Soft Matter ; Volume 7, Issue 22 , 2011 , Pages 10548-10551 ; 1744683X (ISSN) Shariatpanahi, S. P ; Iraji Zad, A ; Abdollahzadeh, I ; Shirsavar, R ; Bonn, D ; Ejtehadi, R ; Sharif University of Technology
    2011
    Abstract
    Direct near field electrospinning is used to produce very long helical polystyrene microfibers in water. The pitch length of helices can be controlled by changing the applied voltage, allowing the production of both microsprings and microchannels. Using a novel high frequency variable voltage electrospinning method we determined the helix formation speed and compared the experimental buckling frequency to theoretical expressions for viscous and elastic buckling. Finally we showed that the new method can be used to produce new periodic micro and nano structures  

    Synthesis of Carbon Nanofibers and Carbon Nanofiber-Carbon Nanotubes Using Poly Vinyl Alcohol Through Electrospinnig Approach

    , M.Sc. Thesis Sharif University of Technology Azami Ghadikolaei, Milad (Author) ; Faghihi Sani, Mohammad Ali (Supervisor)
    Abstract
    The aim of the present thesis was a synthesis of carbon nanofibers (CNFs) derived from electrospun poly vinyl alcohol (PVA) by means of various stabilizers and, moreover, improvement of synthetic CNFs with the incorporation of carbon nanotubes (CNTs). In order to do so, PVA solutions were prepared and electrospun with and without the cadmium salt. In order to do so, PVA solutions were prepared and electrospun with and without the presence of cadmium salt. The resultant polymeric nanofibers were carbonized directly and indirectly. In the case of indirectly carbonization, they were iodinated before the carbonization process. In the case of CNF-CNT composites, after having oxidized by nitric... 

    Study & Synthesis of Biocompatible Scaffolds for Animal Cell Cultures

    , M.Sc. Thesis Sharif University of Technology Riazi Esfahani, Bahar (Author) ; Vosoughi, Manouchehr (Supervisor) ; Alemzadeh, Iran (Co-Advisor) ; Pajoum Shariati, Ramin (Co-Advisor)
    Abstract
    Natural tissues of body consist of Extra Cellular Matrix (ECM) and cells. Scaffold produces a temporary matrix for cells and facilitates oxygen and nutrients transport which enhances tissue regeneration. Therefore, attempts in regeneration of tissues and organs by scaffolds attracted great interest in today’s researchs. Choosing scaffold fabrication method and its polymer type, play a key role in scaffold specifications as they determine scaffold properties. In this project electrospinning was chosen as the scaffold fabrication method which is because of the unique properties of scaffolds fabricated by this method and also its ability in producing micro and nano fibers. At first set of... 

    Fabrication of Gas Sensor Based on Frequency Shift in Quartz Crystals

    , M.Sc. Thesis Sharif University of Technology Mohammadi Aria, Mohammad (Author) ; Sarvari, Reza (Supervisor) ; Irajizad, Azam (Supervisor)
    Abstract
    In this thesis, gas sensors were fabricated based on resonance frequency shift of quartz crystal with covering of polymer fibers and carbon nanostructure materials.¬ Sensing materials were used in two different types of polyvinylpyrrolidone (PVP) and Graphene oxide. Electrospining was used as an efficient, simple and low cost approach for producing polymer and composite fibers with 280nm to 4um diameters. In addition, the effects of changing various parameters such as the concentration of polymer solution and electrospining process time were investigated. Images taken with a scaning electron microscope indicated that the concentration of polymer solution effectively can affect morphology,... 

    Preparation and Characterization of Electrospun Nanofiberous Membranes for Wastewater Treatment

    , M.Sc. Thesis Sharif University of Technology Seyed Shahabadi, Mahdi (Author) ; Bastani, Daruoosh (Supervisor) ; Moosavi, Ali (Supervisor)
    Abstract
    The aim of the current project is preparation, characterization and microfiltration evaluation of nanofiberous membrane. In order to prepare membranes, the electrospinning method was utilized and polyacrylonitrile and N-N, dimethylformamide (DMF) were used as the polymer and the solvent, respectively. As the nanofiber diameter controls the structure of the membrane and also bead formation reduces the membrane uniformity, at first the effects of four most influential electrospinning parameters, such as solution concentration, applied voltage, floe rate, and the distance between needle tip and the collector, on average fiber diameter and bead area density were investigated via response surface... 

    Electric and Buckling Instabilities Effects on the Dynamics and Geometry of the Fibers in Electrospinning

    , Ph.D. Dissertation Sharif University of Technology Shariatpanahi, Peyman (Author) ; Iraji Zad, Azam (Supervisor) ; Ejtehadi, Mohammad Reza (Supervisor)
    Abstract
    Since previous models can not give a complete description for electrospinning electrical instability, using polymer solutions with diifferent properties, the aim of the existing thesis is to propose a new model that covers a range of materials from non-conducting to conducting and from viscous to elastic and also the initial jet’s tension. In addition, since the previous models have used large wave length approxiamtions, using accurate calculations we showed that the new model has better results for small wavelengths of about two times the jet’s radii. To compare the model to experimental results, we designed and made a proper setup to record the electrospinning process for a PEO solution... 

    Fabrication of Artificial skin with Electrospun of Nanofiber made of PCL and PVA

    , M.Sc. Thesis Sharif University of Technology Mohseni, Mina (Author) ; Shamloo, Amir (Supervisor) ; Naghdabadi, Reza (Co-Advisor) ; Vosooghi, Manoochehr (Co-Advisor) ; Firoozbakhsh, Keikhosro (Co-Advisor)
    Abstract
    The main goal of this project is to fabricate the scaffolds including Polycaprolactone and Polyvinyle alcohol nanofibers in order to use as artificial skin. For this purpose, electrospinning parameters have been optimized for various injection rates and the scaffolds containing different percent of PCL and PVA have been made. By investigating the cell growth on these scaffolds, the one made up PVA/PCL (30% ) has been introduced as the best scaffold. To improve biological properties of chosen scaffold, a layer of collagen was coated. The angiogenesis capacity has been improved by adding Heparin to PVA nanofibers. Based on assay of heparin release, it was shown that Heparin is released within... 

    Electrospun composite of polypyrrole-polyamide as a micro-solid phase extraction sorbent

    , Article Analytical and Bioanalytical Chemistry ; 2011 , Pages 1-7 ; 16182642 (ISSN) Bagheri, H ; Aghakhani, A ; Akbari, M ; Ayazi, Z ; Sharif University of Technology
    Abstract
    A micro-solid phase extraction technique was developed using a novel polypyrrole-polyamide nanofiber sheet, fabricated by electrospinning method. The applicability of the new nanofiber sheet was examined as an extracting medium to isolate malathion as a model pesticide from aqueous samples. Solvent desorption was subsequently performed in a microvial, and an aliquot of extractant was injected into gas chromatography-mass spectrometry. Various parameters affecting the electrospinning process including monomer concentration, polyamide content, applied voltage, and electrospinning time were examined. After fabricating the most suitable preparation conditions, influential parameters on the... 

    High flux electrospun nanofiberous membrane: Preparation by statistical approach, characterization, and microfiltration assessment

    , Article Revista Mexicana de Urologia ; Volume 76, Issue 1 , 2016 , Pages 474-483 ; 01854542 (ISSN) Seyed Shahabadi, S. M ; Mousavi, S. A ; Bastani, D ; Sharif University of Technology
    Elsevier Doyma Mexico  2016
    Abstract
    Preparation, characterization and evaluation of new generation of micro-filters based on polyacrylonitrile electrospun nanofiberous membrane (ENM) were thoroughly investigated. First, quantitative relationships between average diameter, bead area density of nano-fibers and certain electrospinning parameters, i.e., concentration, voltage, spinning distance, and feed rate, were established by empirical modeling based on a central composite design. The analysis revealed that concentration, voltage and distance are the significant parameters. Also, adequacy checking indicated the appropriateness of fit for the models. Afterwards, bead-free ENMs with diameter of 100-500 nm were prepared and... 

    Vacuum enhanced membrane distillation for trace contaminant removal of heavy metals from water by electrospun PVDF/TiO2 hybrid membranes

    , Article Korean Journal of Chemical Engineering ; Volume 33, Issue 7 , 2016 , Pages 2160-2168 ; 02561115 (ISSN) Moradi, R ; Monfared, S. M ; Amini, Y ; Dastbaz, A ; Sharif University of Technology
    Springer New York LLC 
    Abstract
    Electrospun hybrid membranes were synthesized using electrospinning of Poly (vinylidenefluoride) - titanium tetraisopropoxide (PVDF-TTIP) sol. Asymmetric post-treatment of membrane conducted for deprotonation of titanate and making hydrophilic/hydrophobic dual characteristics. The membranes were characterized by various methods such as wettability, scanning electron microscopy, infrared spectroscopy, X-ray diffraction and liquid entry pressure tests. For evaluating the separation performance, these membranes were applied in the VMD process to treat water heavy metal contaminants. The effects of operating parameters such as flow rate, temperature and membrane properties as porosity, on... 

    Three-dimensional nanofiber scaffolds are superior to two-dimensional mats in micro-oriented extraction of chlorobenzenes

    , Article Microchimica Acta ; Volume 185, Issue 7 , 2018 ; 00263672 (ISSN) Bagheri, H ; Manshaei, F ; Rezvani, O ; Sharif University of Technology
    Springer-Verlag Wien  2018
    Abstract
    Three-dimensional (3D) polyamide scaffolds were fabricated by applying a solvent bath as the collecting element. Electrospun nanofibers were immersed into the solvent bath to give a material with a laminated 3D texture. In parallel, 2D nanofibers were synthesized and utilized as microextractive phases in a needle trap device to compare the capabilities of 2D and 3D materials in terms of headspace extraction of various chlorobenzenes (chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,4-trichlorobenzene and 1,2,3,4-tetrachlorobenzene). The results demonstrate the superiority of 3D nanofibrous scaffolds over 2D mats. The porosity, morphology, and thermal stability of the 3D scaffolds...