Papers by Keyword: Electrospun

Abstract: The optimized surface morphology of electrospun magnesium oxide (MgO) nanofibers can be achieved based on the parameters set during the fabrication of nanofibers. However, not all materials used during the electrospinning process can be synthesized together as it depends on the application’s needs. This research aims to study the factors that influence the surface area of the MgO nanofibers due to material preparations and electrospinning parameters. The research is based on data obtained from the previous research and was analyzed to evaluate the effect on MgO nanofibers that synthesized with different materials. Based on the data analysis using Brunauer-Emmert-Teller (BET), the surface area for carbon sorbent is higher than organic sorbent. The surface area for carbon sorbent of nitrogen could be achieved up to 324.5 m²/g compared to only 104.8 m²/g using organic sorbent for magnesium oxalate dihydrate (MO). The studies show that the use of nitrogen as a carbon sorbent in the fabrication of electrospun MgO nanofibers may produce a good quality of nanofibers.

Abstract: Electrospun fibers have demonstrated a remarkable potential as a framework structure in the fabrication of cartilage tissue engineering (CTE) scaffolds. Various extracellular matrices have been incorporated into electrospun scaffolds to mimic and simulate the extracellular environment. The objective of this study was to fabricate hybrid constructs using composite electrospun scaffolds based on poly (ε-caprolactone) (PCL) and cartilage-derived matrix (CDM) and fibrin hydrogel to improve the viability and differentiation of human adipose-derived stromal cells (ADSCs) for CTE applications.Initially, PCL and PCL-CDM electrospun mats were fabricated. Fibrin/ ADSCs hydrogel were seeded on PCL- CDM mats and arranged layer-by-layer using sandwich technique. This method has been employed to increase cell seeding and infiltration efficiency through the entire mass of the scaffold. Real-time reverse-transcription polymerase chain reaction (RT- PCR), were performed to examine the expression of collagen types II and X, SOX9 and aggrecan. The production of glycosaminoglycan (GAG) was also tested in vitro by Toluidine blue stain and biochemical assay in the cultured scaffolds.The findings demonstrated that incorporation of CDM in PCL fibers results in improved cell viability. Hematoxylin and eosin staining showed that the sandwich method resulted in homogenous cell seeding within the scaffold. Overall, the RT- PCR, biochemical and histological results, showed that incorporation of the CDM into PCL/fibrin sandwich scaffolds stimulated ADSCs chondrogenesis and produced the products which increased expression of chondrogenic genes. It also, enhanced GAG synthesis compared to PCL/fibrin scaffolds.These findings suggest PCL-CDM/fibrin can be considered as an appropriate hybrid scaffold for CTE applications.

Abstract: Electrospinning has become the most popular nanofibers production technique that many scientists around the world were intrigued by. It is based on electrostatic forces stretching a polymer solution that undergoes bending instability and eventually results in number of fine nanoscaled filaments. The study reports of four processing parameters effect on electrospun polyethylene oxide (PEO) fibers diameter and pores area. Fibers diameter increase results from the increase of time, volume flow rate and tip to collector distance with a critical value of the first two parameters. The pores area showed both decrease and increase after a critical value of the electrical voltage at 19 kV, while the mean pores area decreased with the time increase. Irregular trends of increasing and decreasing trends of the means pores area were noticed with the change of the volume flow rate and tip to collector distance..

Abstract: Recently, the composited nanofiber attraction has been growing from researchers across the world due to its exciting opportunities for use in biomedical applications. In this study, we fabricated electrospun fibers from poly (vinyl alcohol) (PVA) composited with Zinc Oxide (ZnO) nanoparticle for potential use in biomedical applications. From the experimental results, there was not any chemical bonding between the ZnO nanoparticles and the PVA molecules. The effect of concentration of ZnO nanoparticles in PVA solution on the diameter of electrospun fibers was found that the diameter of electrospun fibers increased with raising the concentration of suspended ZnO nanoparticles in solution. This is probably because the effect of nanoparticles on the diameter of electrospun fibers was through their effect on the viscosity of solution. In addition, we found that the diameter of electrospun fibers depended on the solution and processing parameters.

Abstract: In this work, we introduce a synthesis method for a nanofiber membrane made of polyacrylonitrile and verify its filtration ability with micron-size particles. The polyacrylonitrile nanofiber membrane was produced by electro-spun technique with a thickness less than 0.2 mm. The filtration experimental result from micron-size particle penetration proved that after 60-min deposition, the polyacrylonitrile nanofiber membrane successfully filtrated ~99% micron-size particles in solution. We found that uniform morphology, consistent nanofiber diameter without disordered beads will lead to a better filtration performance. This finding will provide a low-cost, environmental-friendly and straightforward filtration approach for future PM_2.5 elimination in an aqueous and harsh environment.

Abstract: Phthalocyanine coated crosslinked electrospun PVA/PAA nanofibers were prepared via electrospinning and esterification reaction. The structure of the as-prepared hybrid nanofibers were characterized by fourier transform infrared spectra, scan electron microscopy and UV–visiable absorption spectroscopy. Their photocatalytic activities were evaluated by the degradation of rhodamine B under visible light, and results showed that it exhibited high activity for degradation of rhodamine B in the presence of hydrogen peroxide. The recycling test was also carried out to prove its reusability in photocatalytic application

Abstract: It has been studied the fabrication of a sheet made of polyvinyl alcohol (PVA) fibers loaded with Fe₃O₄ nanomagnetic materials using an electrospinning technique. The solution for the electrospinner was prepared by stirring nano powder of Fe₃O₄ with a solution of 10% PVA in water at room temperature. The electrospinning process was done under fixed of 15 kV DC voltage, using 12 cm distance between the electrodes, and using a syringe needle having a diameter of 0.4 mm. The morphology of fibers was tested using scanning electron microscope (SEM), while the size of particles was tested using transmission electron microscope (TEM). Moreover, the crystallinity of fibers was tested using Laue and x-ray diffraction, while the magnetic moment was tested using a vibrating sample magnetometer (VSM). The result shows that the PVA sheet composing of fibers having a diameter in the range of 130 mm to 250 mm, accommodating Fe₃O₄ nano particles in the range of 15 mm to 25 mm, indicating a partial superparamagnetic property.

Abstract: In this paper composite nanofiber membranes were prepared by electrospinning technology from poly (vinylidene fluoride) (PVDF)-poly (methyl methacrylate) (PMMA)-SiO₂ blend solutions with different PMMA and SiO₂ contents. It was found that the diameter of electrospun nanofibers was greatly increased with the added PMMA content but decreased with the added SiO₂ content, and when both PMMA and SiO₂ were added the diameter of electrospun nanofibers was decreased. With a proper ratio of the PMMA and SiO₂ added, the electrospum nanofiber membrane could have a suitable diameter with high porosity. The XRD results revealed that electrospun nanofiber membranes contained mainly β-phase crystal structure of PVDF, and its crystalline is reduced with the added PMMA and SiO₂ contents due to the inhibited crystallization of the polymer by the inorganic particles and PMMA during the solidification process. These nanofiber membranes exhibited a high electrolyte uptake, around 300%. Moreover, the incorporation of PMMA and SiO₂ into the nanofiber membrane improved the ionic conductivity from 1.7×10⁻³S/cm to 2.0×10⁻³S/cm at room temperature. Compared with commercial film PE, their cell cycle and charge and discharge performance were also greatly improved.

Abstract: This work was aimed to develop thermally crosslinked chitosan/PVA nanofiber mats. The CS/PVA nanofibers were fabricated using elctrospinning process. The appropriate crosslinking temperatures and crosslinking times in order to thermally crosslinked CS/PVA nanofiber and physicochemical properties of the thermally crosslinked nanofibers were investigated. The morphology of the nanofiber mats was investigated by scanning electron microscopy (SEM). The water insolubilization and FTIR were employed to evaluate the success of crosslinking. Increasing the crosslinking time and temperature, the crosslink was increased, thus causing a decrease of water solubilization. The temperature and time for successful crosslinking were 180-200 °C and 0.5-5 h, respectively.

Abstract: Effects of material and process parameters on the electrospun polyacrylonitrile fibers were experimentally investigated. Response surface methodology (RSM) was utilized to design the experiments at the setting of solution concentration, voltage and the collector distance. It also imparted the evaluation of the significance of each parameter on pore size, contact angle, modulus young and clean water permeability. Effect of applied voltage in micron-scale fiber diameter was observed to be almost negligible when solution concentration and collector distance were high. However, all three factors were found statistically significant in the production of nano-scale fibers. The response surface predictions revealed the parameter interactions for the resultant fiber diameter, and showed that there is negative correlation between the mean diameter and coefficient of variation for the fiber diameters were in agreement with the experimental results. Response surfaces were constructed to identify the processing window suitable for producing nanoscale fibers. A sub-domain of the parameter space consisting of the solution concentration, applied voltage and collector distance, was suggested for the potential nano scale fiber production.