Optimization of Nylon 6 electrospun nanofiber diameter in needle-less wire electrode using central composite design and response surface methodology

In this study, Nylon 6 nanofiber were prepared by needle-less wire electrospinning technique. Since, the fiber diameter determines the porosity, filtration efficiency, and mechanical properties of electrospun nanofiber mat, Central Composite Design (CCD) and Response Surface Methodology have been employed to design the experiments and evaluate the interactive effects of the operating variables such as concentration of the polymeric solution, the distance between two electrodes, applied voltage, and relative humidity (RH%) on the diameter of the Nylon 6 nanofiber. With this connection, an objective of this study was to find out the most influential variables for the finest nanofiber diameter during the spinning with wire type electrode to make the highest possible effective face mask without the addition of any functional additives in it. The overall results show that the combined effect of 12% polymer concentration, 65% RH, 155 mm distance between two electrodes, and 40 kV applied positive voltage have the strongest surface response and are the most significant than the other interactive effects. The Pareto chart illustrates the order of significance affecting the Nylon 6 nanofiber diameter in the order of concentration of the polymeric solution, RH%, the distance between electrodes, and applied positive voltage. Further, bacterial filtration efficiency% of the control sample and five-layer facemask incorporated with optimized nanofiber membrane was found to be 87.4% and 97.5%, respectively, against Staphylococcus Aureus ATCC 6538 bacteria.

Electrospinning of ampicillin trihydrate loaded PLA nanofibers: effect of drug concentration and PLGA addition on its morphology, drug delivery and mechanical properties

The aim of the study is to produce ampicillin trihydrate loaded PLA and PLA/PLGA polymeric nanofibers using HFIP as solvent via electrospinning. The effect of ampicillin trihydrate concentration (4-12%), the addition of PLGA and the amount of added PLGA (20-80%) on the spinnability of the solutions and morphology, average nanofiber diameter, encapsulation efficiency, in vitro drug release and mechanical properties of PLA and PLA/PLGA nanofibers were examined. All nanofibers have shown to have favorable encapsulation efficiency and mechanical properties. As the amount of ampicillin trihydrate increased and PLGA was added, nanofiber diameter increased while mechanical properties decreased. However, as the amount of added PLGA increased, a decrease in nanofiber diameter was observed. The increase in the drug amount caused an increase in the burst effect. The ideal drug concentration was determined to be 8% (F2), as it allows the prolonged and controlled drug release for up to 10 days. While in vitro drug release decreased with the addition of PLGA to PLA, it increased with the increasement of added PLGA to PLA. As a result of the study, it was concluded that the amount of the drug and the added PLGA concentration may affect the average nanofiber diameter, morphology, in vitro drug release and mechanical properties of the obtained electrospun PLA nanofibers.

Electrospinning of a Copolymer PVDF-co-HFP Solved in DMF/Acetone: Explicit Relations among Viscosity, Polymer Concentration, DMF/Acetone Ratio and Mean Nanofiber Diameter

The process of electrospinning polymer solutions depends on many entry parameters, with each having a significant impact on the overall process and where complexity prevents the expression of their interplay. However, under the assumption that most parameters are fixed, it is possible to evaluate the mutual relations between pairs or triples of the chosen parameters. In this case, the experiments were carried out with a copolymer poly(vinylidene-co-hexafluoropropylene) solved in mixed N,N’-dimethylformamide (DMF)/acetone solvent for eight polymer concentrations (8, 10, 12, 15, 18, 21, 24, and 27 wt.%) and five DMF/acetone ratios (1/0, 4/1, 2/1, 1/1, 1/2). Processing of the obtained data (viscosity, mean nanofiber diameter) aimed to determine algebraic expressions relating both to viscosity and a mean nanofiber diameter with polymer concentration, as well as DMF/acetone ratio. Moreover, a master curve relating these parameters with no fitting factors was proposed continuously covering a sufficiently broad range of concentration as well as DMF/acetone ratio. A comparison of algebraic evaluation with the experimental data seems to be very good (the mean deviation for viscosity was about 2%, while, for a mean nanofiber diameter was slightly less than 10%).

Evaluating Antibacterial Efficacy and Biocompatibility of PAN Nanofibers Loaded with Diclofenac Sodium Salt

Side effects of the drugs’ oral administration led us to examine the possibility of using diclofenac sodium (DLF) in a polymeric drug delivery system based on electrospun polyacrylonitrile (PAN) nanofibers, which can be produced cost-effectively and with good applicability for transdermal treatments. The inclusion of DLF in PAN nanofibers increased the nanofiber diameter from ~200 nm to ~500 nm. This increase can be attributed to the increase in the spinning solution viscosity. FTIR spectra confirm the entrapment of the DLF into the PAN nanofibers. X-ray diffraction pattern showed that the inclusion of the DLF in the PAN nanofibers had caused the misalignment in the polymeric chains of the PAN, thus resulting in a decrease of the peak intensity at 2θ = 17o. The DLF loaded PAN nanofibers were efficient against the gram-positive Staphylococcus aureus (S. aureus) and gram-negative Escherichia coli (E. coli), with maximum inhibition zone of 16 ± 0.46 mm for E. coli and 15.5 ± 0.28 mm for S. aureus. Good cell viability ~95% for L929 cells in more extended incubation periods was reported. A gradual release of DLF from the PAN nanofiber was observed and can be attributed to the stability of Pan in PBS medium. Cell adhesion micrographs show that cell-cell interaction is stronger than the cell-material interaction. This type of weak cell interaction with the wound dressing is particularly advantageous, as this will not disturb the wound surface during the nursing of the wound.

Correlation model for fiber diameter of electro-spun membrane using KGM (1,N) model for nano-filtration

Nanofiltration is an important application for electro-spun fiber as it is well characterized by fine fiber diameter, huge density, high penetrability and flexibility. In this paper, the Poly-acrylonitrile (PAN) fiber diameter is determined experimentally by varying four factors such as voltage, flow rate, the distance between spinneret and collector, and mass fraction in the electrospinning process. The fiber diameter is measured through SEM analysis. A highly accurate kernel-based nonlinear multivariable grey model, KGM (1, 1) model is used for the prediction of nanofiber diameter for filtering particulate less than 500 nm. This is proved to be better when compared to the Grey Model First Order One Variable and Multivariable grey model. Based on simulated outcomes, filtration membranes are prepared and tested for filtration efficiency for the airborne particles relating its air permeability, porosity and quality factor.

Morphological/alignment properties of thermoplastic polyurethane nanofiber affected by processing parameters

Thermoplastic polyurethane (TPU) in nanofiber or submicron fiber has widespread application areas including the biomedical applications, such as artificial vein, cell cultivation etc. due to both TPU’s and nanofiber’s morphological properties. The morphology and aligment of nanofibers obtained from electrospinning are significantly affected by process parameters, which affect their end uses. This study aims to investigate the effect of process parameters of electrospinning (nozzle axis type, collector type, collector speed and filler types) on morphological properties (fiber orientation, fiber diameter and porous structure) of thermoplastic polyurethanes. Experimental results showed that nanofiber diameter increased with an increase of collector speed due to the relaxation of extensible TPU nanofiber after spinning process. When the rotational speed of collector reaches to 2000 rpm, the orientation could be observed. Using rotational wire collector resulted in thinner and more oriented fibers compared to rotating cylinder collector. Adding salt particles results in thinnest and highly oriented nanofiber webs. Higly porous surfaces were obtained using coaxial technique at the same feeding rates with miscible solvents for both shell and core. It was seen that using solvent with low boiling point in core may lead to higher porous surfaces. Nanofiber diameter increased using coaxial nozzle instead of single axis nozzle.