Blend Nanofibers Research Articles

Preparation of PAN/PAMAM blend nanofiber mats as efficient adsorbent for dye removal

PAN/PAMAM blend nanofiber mats with different ratios were prepared by electrospinning process for the first time. Their structures were characterized by SEM, N2 adsorption/desorption and contact angle. It was found that PAN/PAMAM nanofiber with ratio of 12:3 has the highest surface area. The adsorption of methyl orange on blend nanofiber was investigated. With the ratio of PAMAM increasing in blend nanofiber, the adsorption capacity increased not very much. Overall the PAN/PAMAM nanofiber with ratio of 12:3 has the best property, its maximum adsorption capacity was found to be 120 mg/g although its surface area was only about 9.97 m2/g. It still maintained an efficient adsorption capacity even at 5th experiment, indicating an effective adsorbent for dye removal. The adsorption isotherm and adsorption kinetics were further investigated. The Freundlich isotherm provided the best fit for dye adsorption and the dynamical data fitted well with the second-order kinetic model. The possible mechanism was discussed.

Preparation of PVA-chitosan blend nanofiber and its dye removal ability from colored wastewater

In this paper, poly(vinyl alcohol) (PVA)-chitosan blend nanofiber was prepared and its dye removal ability from colored wastewater was investigated. The characteristics of the adsorbent were studied using Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). Direct Red 80 (DR80), Direct Red 81 (DR81) and Reactive Red 180 (RR180) were used as anionic dyes. The effects of pH, contact time, adsorbent dosage and initial dye concentration on dye removal were studied. The kinetics and isotherm of dye removal follows pseudo-second order kinetics and the Langmuir isotherm, respectively. Desorption studies showed that adsorbent could be recovered and regenerated. The results show that PVA-chitosan blend nanofiber is a suitable adsorbent with high dye adsorption capacity from colored wastewater.

Electrospinning and characterization of poly (vinyl alcohol)–sericin nanofibers as a potential for tissue engineering applications

Poly vinyl alcohol (PVA) is a hydrophilic, biocompatible, and biodegradable polymer which has found application in biodrugs and tissue engineering. Sericin accompanying silk is a waste which is produced in scouring silk and has interesting properties which has attracted the attention of researchers. Silk sericin is also hydrophilic, biodegradable, and biocompatible. Moreover, it is cheap and anti-cancerous. Mixture of PVA and sericin in the form of 2D membrane or 3D hydrogels has been employed to heal skin damages. This research aimed at electrospinning PVA–sericin blend nanofibers in the form of a mat which has applications in tissue engineering, using dimethyl sulfoxide (DMSO) as an organic solvent. This research showed that the solution of PVA–sericin in DMSO was electrospinnable; however, the addition of urea to the solution made the electrospinning easier. The electrospinning solution contained ratio of 0:100, 10:90, 15:85, 20:80, and 25:75 sericin (%w/w)–PVA (%w/w). The electrospun PVA–sericin nanofibers had an average diameter in the range of 179–285 nm. X-ray diffractometer and differential scanning calorimetry investigations showed no reaction occurring between PVA and sericin. Polyvinyl alcohol 100% was also electrospun in DMSO. Up to now, the electrospinning of PVA in non-aqueous media has not been reported in the literature.

Synthesis of amphiphilic alginate derivatives and electrospinning blend nanofibers: a novel hydrophobic drug carrier

As a kind of novel hydrophobic drug carrier materials, the drug-loaded nanofibers were successfully fabricated using amphiphilic alginate derivative (AAD) and poly (vinyl alcohol) (PVA) by electrospinning method. The AAD was synthesized by amide linkage attachment of octylamine onto the carboxylic group of alginate, which was characterized by the means of elemental analysis, FT-IR spectrometer, 1H NMR spectrometer and fluorescence measurement. Experimental results showed the amidation of alginate was successful, in which the degree of modification was 0.27 and the critical aggregation concentration in 0.15 mol/L aqueous NaCl solution was 0.43 mg/mL. The octyl groups of AAD could effectively make alginate chains flexible and enhance chain entanglements through the hydrophobic interactions between octyl groups. In contrast to sodium alginate (SA)/PVA blend solutions, AAD/PVA blend solutions showed more excellent electrospinnability. Additionally, the different volume ratios of SA or AAD to PVA played an important role in the formation and morphology of the electrospun blend nanofibers. Although the amidation of alginate could not fundamentally alter the spinnability of alginate, the content of alginate in the blend nanofibers was appropriately increased. The new generated drug-loaded AAD/PVA (20/80) blend nanofibers exhibited relatively continuous and uniform nanofibers with the average diameter of 191.72 nm. Compared to the drug-loaded SA/PVA (20/80) blend nanofibers, the drug-loaded AAD/PVA (20/80) blend nanofibers presented a sustained release performance with the slow release of about 76 % λ-cyhalothrin during the initial period of 10 h.

In-vitro release of fragrant l-carvone from electrospun poly(ϵ-caprolactone)/wheat cellulose scaffold

The release kinetics of l-carvone loaded from electrospun poly(ϵ-caprolactone) (PCL) and Wheat cellulose (WC) blend were studied. WC was extracted from wheat straw, a cost effective agricultural waste by the acid hydrolysis method. A homogeneous solution of PCL-WC (13:3wt%) was optimized to produce beadless electrospun PCL-WC blend nanofibers. Further, WC and the prepared electrospun PCL-WC blend fibers were systematically characterized by ATR-FTIR, SEM, XRD, TGA, DTGA, and DSC measurements. The hydrophilic character of the blend fibers was analysed using swelling tests and contact angle measurements. The loading efficiency of l-carvone into the electrospun PCL-WC blend fibers was evaluated to be ∼70%. The in-vitro release of l-carvone from PCL-WC blend fibers followed Korsmeyer–Peppas kinetic model indicating the diffusion mechanism and the maximum release of l-carvone was found to be ∼84% over a period of 30h. These results would offer the prepared PCL-WC blend as an ideal fibrous mesh for fragrant antimicrobial textile applications.

Conductive polyacrylonitrile/polyaniline nanofibers prepared by electrospinning process

Electrospinning of polymer blends solutions offers the potential to prepare novel nanofibers for use in a variety of applications. Conductive blend nanofibers of polyaniline doped with camphorsulfonic acid (PANi-CSA) and polyacrylonitrile (PAN) were prepared by electrospinning process. The influences of PANi-CSA content on the morphological, electrical conductivity, and mechanical properties of the blend nanofibers were investigated. The SEM analysis of the nanofibers samples revealed that the average diameter of the nanofibers decreases with increasing PANi-CSA concentration. The resultant PAN/PANi-CSA blend nanofibers diameters were in the range of 59 to 234 nm. Tensile results showed that 30 wt% PANi-CSA loading to the electrospun PAN/PANi-CSA blend nanofibers gave rise to 10-fold and 3-fold increase in the tensile modulus and tenacity of nanofiber layers, respectively. The electrical conductivity measurements of these nanofibers could be adjusted from ∼10−10 S/cm (insulator) to ∼10−1 S/cm (conductor) by choosing the different amounts of PANi-CSA between 0 and 40 wt%. The significant enhanced mechanical and electrical properties of these PAN/PANi-CSA blend nanofibers can be utilized for quite promising future electronic applications.

Optimizing the activity of immobilized phytase on starch blended polyacrylamide nanofibers-nanomembranes by response surface methodology

In this work, activity of immobilized phytase on blended polyacrylamide (PAAm)/starch nanofibers produced via electrospinning was optimized by computer-aided statistical method of experimental design, response surface methodology (RSM). Thereafter, the role of polymer concentration and percentage of starch in period of enzyme activity were optimized using RSM. We employed these two polymers in blend format as two types of bio-compatible and biodegradable materials including sufficient chemical groups to be appropriate candidates for biological applications. Cross-linking treatments were performed using 3-aminopropyltriethoxysilan (APTES) and glutaraldehyde (GA), and finally phytase enzyme was successfully immobilized on the surface of membranes. First, we used scanning electron microscopy for morphological observation of blended nanofibers. According to the results obtained from response surface method and mean effect assessment, PAAm concentration and percentage of starch as process variables in the experimental design were successfully able to influence the biological properties of immobilized enzyme. Besides, it is also supposed that the presence of starch as a biodegradable and biocompatible natural polymer has a great effect on increasing the unit of enzyme’s activity on the membrane surface.

Composite chitosan/poly(ethylene oxide) electrospun nanofibrous mats as novel wound dressing matrixes for the controlled release of drugs

ABSTRACTThe aim of this study was to develop novel biomedical electrospun nanofiber mats for controlled drug release, in particular to release a drug directly to an injury site to accelerate wound healing. Here, nanofibers of chitosan (CS), poly(ethylene oxide) (PEO), and a 90 : 10 composite blend, loaded with a fluoroquinolone antibiotic, such as ciprofloxacin hydrochloride (CipHCl) or moxifloxacin hydrochloride (Moxi), were successfully prepared by an electrospinning technique. The morphology of the electrospun nanofibers was investigated by scanning electron microscopy. The functional groups of the electrospun nanofibers before and after crosslinking were characterized by Fourier transform infrared spectroscopy. X‐ray diffraction results indicated an amorphous distribution of the drug inside the nanofiber blend.In vitrodrug‐release evaluations showed that the crosslinking could control the rate and period of drug release in wound‐healing applications. The inhibition of bacterial growth for bothEscherichia coliandStaphylococcus aureuswere achieved on the CipHCl‐ and Moxi‐loaded nanofibers. In addition, both types of CS/PEO and drug‐containing CS/PEO nanofibers showed excellent cytocompatibility in the cytotoxicity assays. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 42060.

Fabrication and Properties of High‐Content Keratin/Poly (Ethylene Oxide) Blend Nanofibers Using Two‐Step Cross‐Linking Process

High‐content keratin/poly (ethylene oxide) (PEO) (90/10) blend nanofibers were prepared by electrospinning combined with a two‐step cross‐linking process. The keratin/PEO aqueous solution was firstly mixed with ethylene glycol diglycidyl ether (EGDE) as cross‐linker and then electrospun into nanofibers. The resulting nanofibrous mats were cross‐linked with EGDE vapor to decrease the solubility of nanofibers in water. The morphologies and properties of electrospun fibers were investigated by SEM, FTIR, TG, XRD, and contact angle testing, respectively. The results showed that the morphologies of nanofibers were uniform at the fiber average diameter of 300 nm with negligible bead defects by adding EGDE to keratin/PEO solutions. The cross‐linking results showed that EGDE vapor could improve the hydrophobic property of blended nanofibers. The crystallinity of the keratin/PEO blend nanofiber mat increased from 13.14% for the uncross‐linked sample to 21.54% and 35.15% for the first cross‐linked and second cross‐linked samples, respectively. Free defect nanofiber mats with high keratin content producing from this two‐step cross‐linking process are particularly promising for tissue engineering and cell‐seeded scaffold.

A Novel Nano-Fiber of Iranian Gum Tragacanth-Polyvinyl Alcohol/Nanoclay Composite for Wound Healing Applications

The fibers with smaller pores and higher surface area than regular fibers have enormous applications in tissue scaffolds, protective clothing, and wound healing. Iranian Gum Tragacanth (IGT) is the most common natural polymers which has found with lots of applications recently, and has attractive characteristic like nontoxic nature, biodegradability, higher resistance, antibacterial and good biological properties to bacterial attacks. In the current work, poly vinyl alcohol (PVA)/IGT biocomposite fiber is prepared using electrospinning (ELS) method in aqueous solutions with PVA blended system in a volume ratios of 60/40, 70/30, 80/20, and 90/10 composite with different amount of nano-clay (NC) powder (1% and 3%) to enhance the chemical and mechanical stability. The blended nanofibers are characterized by scanning electron microscopy (SEM), fourier transform infrared (FTIR) techniques. The FTIR analysis indicated that PVA and IGT may be having H+ bonding interactions. The current study reveals that with a higher percentage of IGT in the blend nanofibers, superior degradation, higher chemical and mechanical stability could be obtained. Moreover, the blend nanofibers with 80/20 with 3% NC exhibit improvement in unique properties compared to pure PVA/IGT.

Effects of Chitosan Concentration on the Protein Release Behaviour of Electrospun Poly(ε‐caprolactone)/Chitosan Nanofibers

Poly(ε‐caprolactone)/chitosan (PCL/chitosan) blend nanofibers with different ratios of chitosan were electrospun from a formic acid/acetic acid (FA/AA) solvent system. Bovine serum albumin (BSA) was used as a model protein to incorporate biochemical cues into the nanofibrous scaffolds. The morphological characteristics of PCL/chitosan and PCL/chitosan/BSA Nanofibers were investigated by scanning electron microscopy (SEM). Fourier transform infrared spectroscopy (FTIR) was used to detect the presence of polymeric ingredients and BSA in the Nanofibers. The effects of the polymer blend ratio and BSA concentration on the morphological characteristics and consequently on the BSA release pattern were evaluated. The average fiber diameter and pore size were greater in Nanofibers containing BSA. The chitosan ratio played a significant role in the BSA release profile from the PCL/chitosan/BSA blend. Nanofibrous scaffolds with higher chitosan ratios exhibited less intense bursts in the BSA release profile.

AB2 Y-shaped miktoarm star conductive polyaniline-modified poly(ethylene glycol) and its electrospun nanofiber blend with poly(ε-caprolactone)

The aim of this study is the synthesis, and characterization of novel type AB2 Y-shaped miktoarm star conductive polyaniline-modified poly(ethylene glycol), and preparation of its electrospun nanofibers blend with poly(ε-caprolactone).

Development of novel electrospun nanofibrous scaffold from P. Ricini And A. Mylitta silk fibroin blend with improved surface and biological properties.

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 800nm range with flat morphology. The porosity of ET scaffold is found to be 79±5% with majority of pore diameter between 2.5 to 5nm. 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±0.13MPa and 1.47±0.10MPa 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 14days 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.

Study of sustained release drug-loaded nanofibers of cellulose acetate and ethyl cellulose polymer blends prepared by electrospinning and their in-vitro drug release profiles

Sustained release cellulose acetate (CA) and ethyl cellulose (EC) polymer blend nanofibers loaded with ketoprofen (KET) were successfully prepared by electrospinning. Successful fiber formation has been investigated by using two different binary solvent systems, i.e., acetic acid + distilled water (2:1 v/v) and acetone + N,N-DMAc + ethanol (2:1:1 v/v). Scanning electron microscopy (SEM) images showed that morphological features gradually change as the ratio of both polymers change. Nanofiber diameter also decreases as the CA content is increased in the polymer blend solution from 77.25 ±27 to 72.39 ±30 nm. Drug release profiles were evaluated by in-vitro drug release experiments. Drug release follows a pseudo-Fickian behavior of diffusion and shows a sustained release mechanism. Nanofibers containing more CA show greater controlled release capacity as compared to EC. X-ray diffraction (XRD) patterns of CA and EC polymer blend nanocomposites show that crystalline ketoprofen has changed into an amorphous state. Fourier transform Infrared (FTIR) analysis indicates hydrogen bonding occurs between the drug and the polymer, accounting for molecular integration of the two components. The thermal stability of the prepared polymer blend was also studied using thermo-gravimetric analysis (TGA). A polymer blend sustained release drug delivery system prepared by electrospinning make it possible to fabricate other novel drug releasing systems.

Poly(Vinyl Alcohol)/Pullulan Blend Nanofibres Prepared from Aqueous Solutions Using Electrospinning Method

Poly(vinyl alcohol) (PVA)/pullulan (PULL) blend nanofibres were prepared from their aqueous solutions by electrospinning method. Polymer solutions with different concentrations and blend ratios were used to investigate the effect of polymer concentrations and blend ratios on the morphologies and properties of PVA/PULL nanofibres. At a fixed blend ratio, the total polymer concentrations were also adjusted to find suitable electrospinning condition for preparing uniform and bead-free nanofibres. The as-prepared nanofibres were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. Their mechanical properties were also studied by measuring their tensile strength. The results showed that polymer concentrations and blend ratios have direct influence on the morphologies and properties of PVA/PULL nanofibres. 12 wt.% total polymer concentration and higher PVA contents have been found to be favourable for obtaining uniform and bead free PVA/PULL blend nanofibres with improved mechanical and thermal properties.

In vitro degradation study of novel HEC/PVA/collagen nanofibrous scaffold for skin tissue engineering applications

The aim of this study was focused on the degradation behavior of electrospun (hydroxyethyl cellulose/poly(vinyl) alcohol) HEC/PVA and HEC/PVA/collagen nanofibrous scaffolds, as a potential substrates for skin tissue engineering in two biologically related media: phosphate buffered solution (PBS) and Dulbecco's modified Eagle's medium (DMEM) for 12 weeks incubation period. The scaffolds were characterized at different degradation times by a series of analysis including pH changes of solutions, weight loss, swelling ratio, SEM, ATR-FTIR, DSC, TGA and mechanical properties. The results indicated that HEC/PVA/collagen scaffolds were exhibited slower degradation rate in both medium as compared to HEC/PVA blend nanofibers. All fibers displayed uneven and rough surfaces towards the final week of incubation in both PBS and DMEM solution. As degradation time increased, there were little changes in the chemical structure as determined by FTIR spectra while thermal studies revealed that the melting temperatures and crystallinity of scaffolds were slightly shifted to a lower value. Both HEC/PVA and HEC/PVA/collagen fibers showed significant decrease in Young's modulus and tensile stress over 12 weeks degradation. These results show that these nanofibrous scaffold demonstrate degradation behavior that meets the requirement as potential degradable biomaterials for dermal replacement.

Optimizing parameters on alignment of PCL/PGA nanofibrous scaffold: An artificial neural networks approach

This paper proposes an artificial neural networks approach to finding the effects of electrospinning parameters on alignment of poly(ɛ-caprolactone)/poly(glycolic acid) blend nanofibers. Four electrospinning parameters, namely total polymer concentration, working distance, drum speed and applied voltage were considered as input and the standard deviation of the angles of nanofibers, introducing fibers alignments, as the output of the model. The results demonstrated that drum speed and applied voltage are two critical factors influencing nanofibers alignment, however their effect are entirely interdependent. Their effects also are not independent of other electrospinning parameters. In obtaining aligned electrospun nanofibers, the concentration and working distance can also be effective. In vitro cell culture study on random and aligned nanofibers showed directional growth of cells on aligned fibers.

Improved cellular response of chemically crosslinked collagen incorporated hydroxyethyl cellulose/poly(vinyl) alcohol nanofibers scaffold.

The aim of this research is to develop biocompatible nanofibrous mats using hydroxyethyl cellulose with improved cellular adhesion profiles and stability and use these fibrous mats as potential scaffold for skin tissue engineering. Glutaraldehyde was used to treat the scaffolds water insoluble as well as improve their biostability for possible use in biomedical applications. Electrospinning of hydroxyethyl cellulose (5 wt%) with poly(vinyl alcohol) (15 wt%) incorporated with and without collagen was blended at (1:1:1) and (1:1) ratios, respectively, and was evaluated for optimal criteria as tissue engineering scaffolds. The nanofibrous mats were crosslinked and characterized by scanning electron microscope, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Scanning electron microscope images showed that the mean diameters of blend nanofibers were gradually increased after chemically crosslinking with glutaraldehyde. Fourier transform infrared spectroscopy was carried out to understand chemical interactions in the presence of aldehyde groups. Thermal characterization results showed that the stability of hydroxyethyl cellulose/poly(vinyl alcohol) and hydroxyethyl cellulose/poly(vinyl alcohol)/collagen nanofibers was increased with glutaraldehyde treatment. Studies on cell-scaffolds interaction were carried out by culturing human fibroblast (hFOB) cells on the nanofibers by assessing the growth, proliferation, and morphologies of cells. The scanning electron microscope results show that better cell proliferation and attachment appeared on hydroxyethyl cellulose/poly(vinyl alcohol)/collagen substrates after 7 days of culturing, thus, promoting the potential of electrospun scaffolds as a promising candidate for tissue engineering applications.

A novel fixed-bed reactor design incorporating an electrospun PVA/chitosan nanofiber membrane

In this research, a novel fixed-bed reactor was designed with a nanofiber membrane composed of a polyvinyl alcohol (PVA)/chitosan nanofiber blend prepared using an electrospinning technique. The applied voltage, tip-collector distance, and solution flow rate of the electrospinning process were 18kV, 14.5cm, and 0.5mLh−1, respectively. Brunauer–Emmett–Teller (BET) theory, scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FT-IR) were employed to characterize and analyze the nanofiber membranes. Homogeneous electrospun nanofibers with an average diameter of 99.47nm and surface area of 214.12m2g−1 were obtained. Adsorption experiments were carried out in a batch system to investigate the effect of different adsorption parameters such as pH, adsorbent dose, biomass dose, contact time, and temperature. The kinetic data, obtained at the optimal pH of 6, were analyzed by pseudo first-order and pseudo second-order kinetic models. Three isotherm models and thermodynamic parameters (ΔG°, ΔH°, and ΔS°) were applied to describe the equilibrium data of the metal ions adsorbed onto the PVA/chitosan nanofiber membrane.

Photovoltaic and Thermal Properties of Electrolytes Based on Electrospun Poly(vinylidene fluoride-hexafluoro propylene)/Poly(methyl methacrylate) Nanofibers for Dye-Sensitized Solar Cells

We prepared electrospun polymer nanofibers by electrospnning method and investigated about their applications to dye-sensitized solar cells (DSSCs). Electrospun polymer nanofibers applied to the polymer matrix in electrolyte for DSSCs. To improve the stiffness of polymer nanofiber, poly(vinylidene fluoride-hexafluoro propylene)/Poly(methyl methacrylate) (PVDF-HFP/PMMA) blend nanofibers were prepared and examined. In the electrospun PVDF-HFP/PMMA (1:1) blend nanofibers, the best results of VOC, JSC, FF, and efficiency of the DSSC devices showed 0.71 V, 12.8 mA/cm2, 0.61, and 5.56% under AM 1.5 illumination.