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Fiber production in nanoscale prepares high surface contact for fibers and leads to the improvement of their properties with respect to other fibers. A convenient and effective method for nanofiber production with different diameters is electrospinning. Various effective parameters on electrospinning processes, including environmental, equipment, and solution variables can produce fibers with different morphologies. PVA has been used in various fields of applied research because of its high thermal stability, biocompatibility, non-toxic and solubility in water. The published reports indicated that properties of the PVA are improved with the addition of bentonite. In this research, to prepare PVA/nano-bentonite nanofiber membrane, the optimum amounts of three effective variables on the above-mentioned processes were determined. According to the obtained results, the voltage of 11 kV, the feeding rate of 0.5 mL/h and bentonite concentration of 3% w/w were optimum conditions for the process of PVA/nano-bentonite nanofiber composite production. In this condition, the average diameter of produced nanofibers was 243 nm with the standard deviation of 0.0551 and the tensile strength of 7.64 MPa. The results showed that the addition of bentonite to PVA increase intensity of nanofibers and decrease the diameter of nanofibers from 308 nm to 243nm.Therfore, the produced PVA/bentonite nanofiber composite is a good membrane for water treatment.

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The porosity of electrospun nanofibers web is a significant parameter affecting various areas of nanofibers applications. Thus, at first, the effect of most effective parameters, the concentration of polymer solution and flow rate, on the diameter of polyvinyl alcohol nanofibers, as a dissolving component, were investigated. Afterward, the hybrid web of polyamide 6/polyvinyl alcohol (PA/P) was prepared via a two-sided dual-nozzles electrospinning method. The morphology, diameter, pore size of nanofibers web and the effect of dissolving constituent were studied based on images of the scanning electron microscope. To measuring the porosity of nanofibrous webs, three practical and straightforward methods that have been proposed in the literature were utilized. It was observed that when one component was dissolved, the diameter of the resultant web was decreased, and the porosity has been reduced to about 70% based on the best selected method of porosity. Additionally, the average pore size of electrospun PA6 webs has been decreased about 30-58% relative to the original hybrid webs.

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Research Subject: One of the important methods in the treatment of skin wounds is the use of wound dressings. Recently, the use of polymer-based wound dressings has become increasingly common. The use of natural polymers is very important in wound dressings. The aim of the present study is to design and manufacture a polyvinyl alcohol/aloe vera wound dressing with the capability of healing skin wounds.
Research Approach: The electrospinning method was applied to prepare the samples. Aloe vera gel was first extracted, purified, and powdered by freeze-drying. In all samples, the amount of polyvinyl alcohol and aloe vera powder was fixed at 8 wt.%. This value was selected empirically based on the quality of the produced fibers. Different samples including different amounts of polyvinyl alcohol and aloe vera were produced and their properties including morphology, tensile strength, swelling, degradability, and antimicrobial properties were investigated.
Main Results: The results showed that the dropless random oriented fibers with uniform diameter were produced. The diameter increased with increasing aloe vera contribution, which was attributed to an increase in viscosity due to the presence of aloe vera. With increasing aloe vera contribution in the samples, tensile strength decreased and the elongation percentage increased. The swelling behavior of the specimens was evaluated by measuring the weight of the specimens in a simulated skin environment and the results showed that the presence of aloe vera increased the hydrophilic properties of the specimens. Antimicrobial activity of the samples against two gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa was investigated using the disk diffusion method and it was found that the presence of Aloe vera in the samples brought antimicrobial activity against Pseudomonas aeruginosa. Finally, the findings of this study confirm the feasibility of using polyvinyl alcohol /aloe vera for the production of the electrospun wound dressing.

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Research subject: Polymer nanofibers have attracted much industrial interest over the past decade. In general, these fibers are suitable for a variety of applications including medical applications, insulation, capacitors, advanced aerospace technologies, and so on. Specifically in aerospace technology, the used materials must be thermally stable with suitable electrical conductivity. However, many of these polymer nanofibers suffer from low temperature degradation and low electrical conductivity, limiting their use in many potential applications. Graphite has unique properties such as high conductivity and high thermal stability. This exceptional material can be included as a nanoparticle in polymer nanofibers to modify electrical and thermal properties.The aim of this research was to investigate the effect of addition of graphite nanoparticle on thermal and electrical propertiesof polymer fibers.
Research approach:  For this purpose, polyvinyl alcohol 72000 (PVA) as a non-conductive polymer and graphite nanoparticles were used. Polyvinyl alcohol-graphite nanofibers were synthesized method by electrospinning technique under optimized parameters. The optimum conditions for the electrospinning process were: PVA concentration of 8%, applied voltage of 22 Kv, flow rate of 10 ml and tip/collector distance of 20 cm.
Main results:  Scanning electron microscopy (SEM) studies showed that produced PVA fibers were smooth, continuous without any bead, with a diameter of about 350 nm. The PVA / graphite nanofibers were also smooth but much thinner (about 200 nm) than PVA fibers at the same processing parameters. Moreover, X-ray patterns of PVA/graphite nanofibers include peaks of graphite particles in the structure and slso the suppression of crystallinity.  According to the results of 4 point probe teste, by increasing weight percentage of graphite in the fibers, electrical conductivity increased up to 0.5 . The thermal behavior of PVA nanofibers after mixing with graphite was also investigated by differential calorimetry analysis (DSC) and TGA. It was demonstrated that PVA / graphite nanofibers are thermally stable up to 300 ° C.

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Aims: Recently, polymer-based nanofibrous scaffolds have attracted great attention due to their significant antibacterial properties in the field of dermatological applications. In this study, a polycaprolactone-based nanofibrous scaffold has been fabricated using the electrospinning method. The aim of this study was to evaluate the antibacterial effect of electrospun nanofibrous structures. Materials and Methods: In this experimental study, the structure and bacterial attachment on polymeric nanofibrous scaffolds were studied by Scanning Electron Microscopy (SEM). In addition, antibacterial properties of nanofibrous scaffolds were studied on two gram-negative bacteria of Escherichia coli and Pseudomonas aeruginosa and two gram-positive bacteria of Staphylococcus aureus and Streptococcus mutans, using microdilution method and biofilm assay. Moreover, MTT assay was performed on HeLa and human fibrosarcoma cell line (HT1080) cancerous cell lines to evaluate the cell viability.
Findings: The results of this study showed that nanofibrous scaffold revealed a significant antimicrobial and anti-biofilm formation effect on all of the studied bacterial strains, but in microscopic observations and microdilution assay was observed on Pseudomonas aeruginosa in 1mg/ml of nanofibrous scaffold extract concentration, while the major effect in biofilm assay was observed in 8µg/ml of extract concentration. Moreover, the cell viability studies showed that the most significant effect was shown on HT1080 cell line which has drastically decreased by 40% after 48 hours in comparison with the control.
Conclusion: These results show that electrospun nanofibrous PCL-based scaffolds are potentially promising for dermal tissue engineering applications, due to anti-biofilm effects and capability of reducing the number of cancerous cells in the wound site.

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Objective: Tissue engineering is an (interdisciplinary field that applies polymeric scaffolds to control tissue formation in three-dinemtion (3D). The scaffold provides the microenvironment (synthetic temporary extracellular matrix) for regenerative cells, supporting cell attachment, proliferation, differentiation, and neo tissue genesis due to their suitable chemical, physical and biological structures. In this study, chitosan/poly (vinyl alcohol) (CS/PVA) was exploited as scaffold for nerve regeneration. Materials and Methods: Electrospinning was used to fabricate CS/PVA nanocomposites for U373 cells seeding and proliferation. Electrospinning is a versatile and simple method to fabricate non-woven thin layer fibers from polymeric solutions. Consequently, the biocompatibility of CS/PVA nanocomposite was evaluated using biological assays and cell attachment study. Results: Results indicated that CS/PVA nanocomposites with 15/85 proportion shown an almost homogenous network of the electrospun fibers and confirmed that they can be knitted in meshes and improve U373 cells proliferation and cell attachment. Conclusion: The nano-sized CS/PVA scaffolds are nontoxic and biocompatible which can promote proliferation of U373 cells and their appropriate adhesion to nanocomposite for improved peripheral nerve regeneration.

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Objective: Nowadays, as the field of neural tissue engineering advances, the fabrication and application of combined structures open a new window of research for the regeneration of nervous system injuries. In this study, chitosan/poly(vinyl alcohol)-carbon nanotube nanocomposites has been exploited as scaffolds. Materials and Methods: Electrospinning was used to fabricate chitosan/poly(vinyl alcohol)-carbon nanotube scaffolds. Raman spectroscopy and scanning electron microscopy (SEM) was used to evaluate the chemical and physical structure of the electrospun scaffolds. Then, the biocompatibility of the scaffolds was evaluated using MTT assay and Neutral red assay. Results: The results showed that the chitosan/poly(vinyl alcohol)-carbon nanotube nanocomposites have suitable structural and morphological aspects for human brain-derived cells growth and proliferation. Therefore, the cells could maintain their usual morphology while adhering to the surface of the nanocomposites due to an appropriate biocompatibility of the scaffolds. Conclusion: Chitosan/poly(vinyl alcohol)-carbon nanotube nanocomposites could enhance the proliferation of human brain-derived cells due to their proper structure and biocompatibility.

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Structured polymer fibres with a diameter of about several micrometers to a few nanometres have attracted considerable attention in various scientific fields. Among the various methods applied to produce the fibre, electrospinning is proposed as one of the novel techniques. In this method, the non-woven structures are produced by applying electrical field to the polymer solution and due to the solvent evaporation. In the electrospraying method (as a branch of the electrospinning technique), the manufacturing process of the fibre production shifts to the production of capsules and thus conditions are provided for other varied applications of this technique. The electrospun fibres are applied in the processes such as filtration, tissue engineering, drug and nutraceutical targeted delivery as well as reinforcement of composite systems. In this comprehensive paper, relying on the experiences of the author, the introduction of electrospinning, the method of its implementation, and its potential applications in the food industry as well as the prospect of this technique in the industry will be discussed. Indeed, the entrances of this new approach to the food industry can induce significant alterations in this area of science.

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Protein-based carriers have several advantages over lipid, carbohydrate, synthetic polymers and inorganic colloidal carriers in terms of biodegradability, availability, high capacity of drug transplantation. Electrospinning is a process that uses electric fields to spin fibers with diameters ranging from hundreds to tens of nanometers. Zein is the major storage protein of maize. Vancomycin is a broad spectrum antibiotic that acts against gram-positive bacteria. The purpose of the present study was to evaluate the properties of nano-fibrous membrane containing vancomycin antibiotics and to study release and antibacterial properties. Electrospinning method was used to prepare a polymer matrix of a zein nanofiber containing vancomycin antibiotic. The physical properties of the fibers, the method of drug release and the antimicrobial activity of vancomycin loaded fiber were investigated. The morphology of the nanofiber was confirmed using scanning electron microscopy and the formation of uniform filamentary fibers was confirmed. The results of Fourier transform infrared indicated no interaction between zein and vancomycin. The DSC results indicated that vancomycin was physically in amorphous state. The results showed that after 168 h, about 55% of the loaded vancomycin on the fibers was released. A significant difference was observed between the rate of drug release at different times (p <0.05). There was also a decrease in the number of bacteria encountered with vancomycin loaded zein fibers compared to non-loaded zein fiber and control samples. Keywords: Nanofiber, Zein, Vancomycin, Electrospinning, Drug delivery

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It is inevitable to replace the tissues and organs that were disrupted due to trauma or various diseases. One of the methods that can help to speed up the regeneration of wounds is to improve the technology of wound dressings. In the current research, by using the properties of polyurethane nanofibers and improving their properties with additives including graphene oxide, selenium nanoparticles, and henna plant extract, it was aimed to improve the performance of wound dressings. After finding the optimal concentration for the electrospinning machine, DMSO solution containing 12 wt.% polyurethane was used to produce wound dressing nanofibers. The images from scanning electron microscope (SEM) confirmed the production of uniform scaffolds composed of polyurethane nanofibers. Antibacterial properties and mechanical properties of the fabric were studied to check the performance of the manufactured fabric as a wound dressing. For the PU-GO-Se-Henna composite sample, the antibacterial activity against two bacteria, S.aureus and E.coli, was 3.26 and 2.85, respectively, which indicates the very attractive antibacterial properties. This sample reached a tensile strength of 92 MPa in the tensile test, which showed a 104% increase in strength compared to the pure polyurethane sample.
 

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Nowadays the use of natural and biodegradable nanofibers in the packaging industry due to the contamination of non-biodegradable polymers in food packaging is dramatically obvious and electrospinning is one of the easiest ways to produce these nanofibers. In this study, the electrospinning of collagen polymer type I (extracted from the rat-tail) with Beta Cyclodextrin and Nanoclay was investigated and Acetic acid was used as a safe solvent in terms of the environment. After designing the experiments using an experimental design software (Design Expert 7.0), the effects of independent variables such as weight-weight ratio of Beta Cyclodextrin to Collagen (X₁), Volume-weight ratio of Nanoclay to Collagen (X₂) and solution feed rate (X₃) was evaluated on dependent variable, including nanofibers diameter (Y₁). Also, electrospinning process was performed with a voltage of 12 Kv and the distance between the needle and the collector 120 mm at ambient temperature and pressure. Nanoclay have been used due to barrier and antimicrobial properties; in addition, Beta cyclodextrin was used for the specificity of the structure that causes hydrophilic and hydrophobic surfaces. Furthermore, to investigate the shape of nanofibers Scanning Electron Microscopy, to investigate the structure Transform Infrared Spectroscopy, to investigate existing elements X-Ray Fluorescence Spectroscopy and to determine thermal resistance Differential scanning calorimetry was applied. The results showed that optimal nanofiber with a average size of 123.01 nm and a flawless structure with a viscosity of 145.33 mpa.s was obtained.

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Objective:More similarity to in vivo medium may help to increase the proliferation and differentiation of cells at in vitro condition. The present study has investigated the effect of a dynamic mediumand nano hydroxyapatite (nHA) presence on proliferation and differentiation of mesenchymal stem cells (MSCs) to bone cells using electrospun polycaprolactone (PCL) scaffolds. Methods: We prepared PCL and PCL-nHA scaffolds by electrospinning. After static culturing of the scaffolds with MSCs, the scaffolds in a 14-day period,  they were divided into two groups of static and dynamic cultures. The dynamic culture scaffolds were placed on a shaker. Cell proliferation and differentiation at days 3, 7 and 14 were investigated by MTT, and the calcium and alkaline phosphatase assays. Results: The obtained results from the MTT assay on day 14 showed an increase of 1.1 times in cell proliferation in the dynamic culture compared to the static culture. During this period, the calcium content produced by cells in the dynamic culture at day 14 were 1.23 times higher for the PCL scaffold and 1.46 times higher for the PCL-nHA scaffold compared to the static culture. Alkaline phosphatase levels for the dynamic state PCL scaffold were 1.24 times more and for the PCL-nHA scaffold they were 1.28 times more compared to the static culture at day 14. Conclusion: The obtained results from dynamic culture, showed higher proliferation and differentiation of stem cells to bone for both PCL and PCL-nHA scaffolds compared to the static culture. The amount of cell proliferation and differentiation in the scaffolds that contained nHA was more than scaffolds that did not have nHA.

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In recent years, electrospinning that has the capability to form polymeric nano-/microfibers has gained substantial attention for fabrication of tissue engineering scaffolds. The morphological resemblance to native extracellular matrix (ECM), high surface to volume ratio, high porosity, and pore interconnectivity are amongst the brilliant features of electrospun structures. The high surface area to volume ratio and interconnected pores of these fibrous meshes confer desirable cell attachment and growth. However, due to small pore sizes and high packing density of electrospun nanofibers, cell penetration into a conventional electrospun mat is completely restrained. Scarce cell infiltration in turn prohibit cell migration into internal parts of the scaffold, cause inhomogeneous cell distribution throughout the structure, limit vascularization, and impede tissue ingrowth. In fact, traditional electrospun nanofibrous scaffolds in practice act as two-dimensional (2D) surfaces rather than three-dimensional (3D) microenvironments. Thus far, a number of approaches have been employed to solve this problem, which range from simple variations in electrospinning parameters to intricate post-processing modifications. Some efforts directly manipulate the electrospun mat characteristics to enhance cell penetration, while others combine cells with scaffolds or encourage cells to migrate into internal parts with different stimuli. In the present study, we have attempted to provide an overview of different approaches offered for improving cell infiltration in electrospun scaffolds.

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Artemisia is an important medicinal plant which is widely used in the treatment of skin diseases and it has antimicrobial properties. This research was carried out with the aim of making nano-fibers with Artemisia sieberi Besser extract to study its antimicrobial properties against Pseudomonas aeruginosa and Staphylococcus aureus bacteria. Artemisia extract and electrospinning solution containing 0.2 g of polyethylene oxide, 0.05 g of chitosan and 1.5 ml of acetic acid were prepared and then nanofibers were produced by electrospinning of the solutions. Artemisia Extract loading with 100 mg/ml extract had a significant effect on the diameter of fibers and the average fber diameter with Artemisia extract (218.4 nm) compared to the fibers without extract (204.8 nm) were higher. The tensile stress at the tear point of the nanofibers with Artemisia extract (3.04 MPa) was lower than the fibers without the extract (3.46 MPa) and elongation at break was higher (7.6%).The nanofibers with the extract had more resistance temperature than non-extract fibers. This is due to the crystal state of Artemisia extract in the fibers. The nanofibers produced with Artemisia extract had inhibitory properties for both studied bacteria. Nanofibers with 100 mg/ml extract completely controlled the bacterial growth. Nanofibers with 20 and 50 mg/ml of extract had a better inhibitory effect on Pseudomonas aeruginosa than Staphylococcus aureus. The Addition of Artemisia extract improved the antimicrobial properties of chitosan nanofibers.

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Objective: In the present study we investigated the effect of a dynamic culture in a shake flask bioreactor (SFB) on the proliferation and differentiation to osteoblasts for human mesenchymal stem cells (hMSCs) cultured on multilayered electrospun PCL-nHA scaffolds.
Methods: First, we prepared PCL-nHA scaffolds by electrospinning. After culturing the hMSCs on the scaffolds in a static state, the seeded scaffolds were divided into two groups (static and SFB culture) and incubated up to 21 days. We assessed biocompatibility and cell differentiation by the MTT, calcium, and alkaline phosphatase (ALP) assays on days 7, 14, and 21.
Results: The MTT assay evaluated hMSCs proliferation rate on the scaffold layers. There was greater cell proliferation (optical density values) on the layers in the bioreactor (OD=2.18) compared to the static state condition (OD=1.68) on day 21. In order to study osteogenic differentiation, we determined the amount of calcium deposition and ALP activity. We observed a 1.6-fold greater level of calcium deposition for the dynamic culture compared to the static culture, which showed increased cell differentiation within the bioreactor on day 21. The ALP results showed that during 14 days, ALP activity within the bioreactor was 1.55-fold higher than the static culture.
Conclusion: The SFB culture displayed a higher proliferation and differentiation of stem cells on PCL-nHA multilayered scaffolds compared to the static state condition.
 

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The mixture of cellulose acetate (CA), and poly (ethylene oxide) was electrospun into Nanofibrous webs using an acetic acid solution. The impact of cellulose acetate (CA)/ polyethylene oxide (PEO) ratio (1, 1.5, 2 wt %), sodium dodecyl sulfate (SDS) (0, 1.5, 3%, w/w) and ammonium oxalate (3%, w/w) on the diameter, tensile strength, elongation and porosity (PO) of the Electrospun Nano-fibers (ENFs) were enhanced applying response surface methodology-central composite rotatable design (RSM-CCRD). The ENFs were formed of non-woven fibers with a maximum diameter of 163 nm. Second-order polynomial models with high R² values (0.86–0.97) were developed using Cubic analysis. The outcome revealed that the ENFs morphology and diameter were noticeably affected by CA, PEO, and SDS. The overall optimum condition was identified to be at the compounded level of CA to PEO ratio of 2 wt % and SDS content of 3% (w/v). At the best point, diameter, surface tension, elongation, and porosity of the fabricated electrospun nanofibers (ENFs) were 99 nm, 0.017 N/mm², 5 mm and 17.54 respectively. The most fabricated ENFs were uniform and bead-free with high active sites and mechanical strength, which could be used in different fields.

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Objective: Tissue engineering, as an interdisciplinary field, assists cell therapy by using scaffolds, cells, and growth factors since 30 years ago. Cells isolated from the body should be supported by a scaffold which could mimic the function and structure of natural extracellular matrix (ECM). To accomplish this goal, we have fabricated and characterized synthetic wet electrospun poly(lactic) acid (PLA) scaffolds.
Methods: ThePLA polymer was used at various concentrations (10%, 13%, 15%, 17%, 20% w/v) with a novel architecture produced by a wet-electrospinning process for tissue engineering applications. In the wet electrospinning method, we used an aqueous solution of sodium hydroxide (NaOH) as the coagulation bath. Then, we characterized the biocompatibility and morphology of these scaffolds by the MTT assay and SEM, respectively.
Results: The data collected from the characterization of scaffolds and in vitro human Wharton’s jelly-derived stem cells/scaffold culture showed that the 15% w/v of PLA with high porosity was the best polymer concentration in terms of cell attachment and proliferation.
Conclusion:Electrospinning PLA at the 10% or 20% w/v concentrations was difficult. Additionally, they could not provide a favorable matrix for cell proliferation and attachment. However, the results have suggested that the novel nanofiber fabrication system would be very useful for the structure control of 3D nanofiber fabrics.

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The use of medicinal plants in food has a long history. Flaxseed oil and eucalyptus essential oil are highly regarded due to their biological properties. In this research, the aim is to investigate the antimicrobial properties of zein nanofibers containing flaxseed oil and eucalyptus essential oil to control staphylococcus aureus and escherichia coli bacteria in a laboratory environment. For this purpose, flaxseed oil mixed with eucalyptus essential oil in zein solution. Then, it was converted into nanofibers using an electrospinning machine. In order to study the characteristics and antimicrobial properties of the nanofibers, tests including scanning electron microscopy (SEM), fiber diameter determination with Image J software, atomic force microscopy (AFM), X-ray diffraction (XRD), thermal gravimetric analysis (TGA) were performed. Investigation of antimicrobial properties of produced nanofibers by disk diffusion method were performed. The SEM results showed that the morphology of the electrospun fibers was uniform and free of beads. AFM images represented three-dimensional and tubular images of fibers obtained from electrospinning zein/flaxseed oil/eucalyptus essential oil. The X-ray diffraction pattern showed an increase in the crystallinity intensity of the treatments compared to the control sample. Based on thermal analysis results, eucalyptus and flaxseed oil increased the thermal stability of zein nanofibers. The results showed that the addition of flaxseed oil to eucalyptus essential oil strengthened the antimicrobial properties of nanofibers. According to the results of the present research, the zein/flaxseed oil/eucalyptus essential oil fibers can be used as natural antimicrobials.