Diameter Of Nanofibers Research Articles

Fabrication and Characterization of Electrospun Waste Polyethylene Terephthalate Blended with Chitosan: A Potential Single-Use Material

Textile single-use products are dominantly used for hygiene and personal care, many of which are non-biodegradable and are frequently discarded into sewerage systems, thus causing blockages. Thus, there is a need to move towards water-soluble textiles. This research study focuses on transforming or repurposing biomass material and synthetic reusable waste plastic materials to improve waste. Chitosan (CS) nanofibers could be used in single-use nonwoven fabric or biodegradable tissues, as the water-soluble properties of chitosan nanofibers make them the perfect material for single-use applications. Furthermore, CS was blended with polyethylene terephthalate (PET) polymer and PET-based waste plastic (CS-WPET) to slow the CS nanofibers' water degradability and strengthen the durability of the nanofiber which could be used as air filters. The CS-TFA and CS-TFA/DCM nanofiber diameters were 95.58 ± 39.28 nm or 907.94 ± 290.18 nm, respectively, as measured from the HRSEM images. The CS-PET and CS-WPET hybrid nanofibers had fiber diameters of 246.13 ± 96.36 or 58.99 ± 20.40 nm, respectively. The thermal durability of the nanofibers was tested by TGA, which showed that CS-TFA/DCM nanofibers had sufficient thermal stability up to 150 °C, making them suitable for filter or fabric use at moderate temperatures. The blended nanofibers (CS-PET and CS-WPET) were thermally stable up to 160 °C. In the aqueous medium stability test, CS-PET and CS-WPET hybrid nanofibers had a slower degradation rate and were easily dissolved, while the CS nanofibers were rapidly and completely dissolved in an aqueous medium. Blending waste PET with CS allows it to be recycled into a useful single-use, non-woven textile, with greater water solubility than unmodified PET nanofibers but more durability than CS nanofibers on their own.

FABRICATION AND CHARACTERIZATION OF ALOE VERA AND TEA TREE OIL LOADED ANTIMICROBIAL NANOFIBEROUS DRESSING

Skin infections due to microbes are reported with high spread and reportedly affected one –third of the world population. Connective tissue cells produce collagen and connective tissue fibers to heal wounds of skin and white blood cells produce antibodies to fight against harmful microbes. This study presents the process of synthesis of nanofiberous dressing loaded with Aloe vera and tea tree oil. Aloe Vera and Tea tree oil contain glucomannan and terpinin-4-ol, which help in the production of collagen and kill microbes. The surface morphology of prepared dressing was studied using Scanning Electron Microscope micrographs. The average diameter of nanofibers was measured to be 137.32nm. Fourier transform infrared spectroscopy of nanofiberous dressing confirmed the loading of aloe vera and tea tree oil. Drug release profile was analyzed by UV-vis spectroscopy. It was observed that 100% drug released within 12 minutes. The antimicrobial properties of prepared fibers against Aspergillus Niger (fungi) and Escherichia coli (bacteria) were systematically evaluated. The results showed that aloe vera- tea tree oil composite fibrous dressing was found to be effective for antimicrobial activity.

Green Electrospinning of Biodegradable Cellulose Acetate Nanofibrous Membranes with Tunable Porosity

The electrospinning of polymer nanofibers has received significant attention owing to their high surface-area-to-volume ratio, high porosity, adjustable pore size and texture, and highly interconnected porous structure. In particular, the electrospinning of biodegradable cellulose acetate (CA) nanofibers has sparked interest in diverse applications, including drug delivery systems, scaffolding for tissue engineering, air filtration, and affinity membrane systems. However, the electrospinning process has been mostly performed using toxic and hazardous solvents and additives. We developed electrospun CA nanofibers using a green solvent system comprising dimethyl carbonate and cyclopentanone. The use of green additives, namely, tetrabutylammonium bromide salts and sophorolipid-based biosurfactants, obtained from honey yeast, substantially improved the spinnability of the CA solution. Moreover, the nanofiber diameter and porous texture were tunable by adjusting the solvent ratio. Pore generation was induced using volatile dimethyl carbonate, which quickly evaporated from the fiber jet. Molecular dynamics simulations demonstrated that the electrospinning process can be divided into three stages. The addition of the biosurfactant facilitated the evaporation process and improved the uniformity of the nanofibers. Furthermore, the nanofibers can be degraded using esterase and cellulase enzymes. To summarize, the electrospinning of ultrafine CA porous nanofibers with tunable morphology was achieved using green solvents and additives.

Characteristic Evaluation of Recombinant MiSp/Poly(lactic-co-glycolic) Acid (PLGA) Nanofiber Scaffolds as Potential Scaffolds for Bone Tissue Engineering.

Biomaterial-based nanofibrous scaffolds are the most effective alternative to bone transplantation therapy. Here, two recombinant minor ampullate spidroins (spider silk proteins), R1SR2 and NR1SR2C, were blended with Poly(lactic-co-glycolic) Acid (PLGA), respectively, to generate nanofiber scaffolds by electrospinning. The N-terminal (N), C-terminal (C), repeating (R1 and R2) and spacer (S) modules were all derived from the minor ampullate spidroins (MiSp). The physical properties and structures of the blended scaffolds were measured by scanning electron microscopy (SEM), water contact angle measurement, Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), and Tensile mechanical testing. The results showed that blending of MiSp (R1SR2 and NR1SR2C) reduced the diameter of nanofibers, increased the porosity and glass transition temperatures of nanofibrous scaffolds, and effectively improved the hydrophilicity and ultimate strain of scaffolds. It is worth noting that the above changes were more significant in the presence of the N- and C-termini of MiSp. In cell culture assays, human bone mesenchymal stem cells (HBMSCs) grown on NR1SR2C/PLGA (20/80) scaffolds displayed markedly enhanced proliferative and adhesive abilities compared with counterparts grown on pure PLGA scaffolds. Jointly, these findings indicated recombinant MiSp/PLGA, particularly NR1SR2C/PLGA (20/80) blend nanofibrous scaffolds, is promising for bone tissue engineering.

Preparation and characterization of nanofibrous mats to enhance the anti-viral properties of nonwoven fabrics in medical sectors

This work suggests the preparation of antiviral nonwoven textile to be used in the medical sectors, namely, surgical gowns, bed sheets, and face masks. This was achieved by the preparation of nanofibrous mats (NFM), of different polymers with potential antiviral characters, on nonwoven polypropylene (PP) fabric. NFMs were prepared by electro-spinning of different polymer composites in formic acid using nozzle-less electro-spinneret. Chemical and physical properties were carried out for the prepared nanofibrous mats using Fourier Transform Infrared Spectroscopy (FTIR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and X-ray diffraction pattern (XRD). The morphological structure of the electro-spun NFM was investigated by scanning electron microscopy (SEM). The prepared NFMs were characterized by measuring their nanofiber diameter, porosity, thickness, and air permeability. The influence of different polymers were statistically analyzed using One-way ANOVA, also Tukey Honest Significant Difference test (Tukey post hoc test) was measured. The radar chart was evaluated to determine the best behavior of samples. The results and analyses exhibited enhanced antiviral activity for the PP nonwoven fabric and the results which agreed with comfort properties introduced by the radar chart.

Metal Oxide Electrospun Nanofibrous Membranes for Effective Dye Degradation and Sustainable Photocatalysis

The fabrication of metal oxide nanofibers using (titanium (IV) isopropoxide) and (tin (IV) tert-butoxide) of weight ratio 1:1 precursor in presence of poly (vinyl pyrrolidone) as a binder using a well-known electrospinning technique is reported. The average diameter of TiO2, SnO2, and composite TiO2-SnO2 nanofibers were found to be in the range 75–110 nm. The nanofibers were characterized using thermogravimetric analysis (TGA) to understand the polymer evaporation temperature and further analyzed using scanning electron microscopy (SEM) to study the morphology of the nanofibers. The oxidation states of titanium (Ti) and tin (Sn) ions were analyzed using X-ray photoelectron spectroscopy (XPS), indicating that the TiO2 undergoes a change even after loading SnO2. The photocatalytic efficiency of the composite TiO2-SnO2 fibers was investigated to study the degradation capabilities under ultraviolet (UV) light towards industrial polluting dyes such as Alcian Blue, Alizarin Red S, Bilirubin, Brilliant Blue, Bromophenol Blue, and Rhodamine B ITC. Rhodamine B showed a significant degradation rate of about 0.0064 min−1 in comparison to the other dyes.

Investigation of silk fibroin-lanolin blended nanofibrous structures

• Nanofiber patches did not show antibacterial properties and biocompatibility. • Mechanical properties increased with the increase of lanolin ratio in the structure. • In cell culture analysis, cells lose their viability over time. In this study, nanofiber patches, a blend of the Silk fibroin(SF)/poly (caprolactone) (PCL)/Lanolin, loaded with different concentrations, were successfully synthesised by the electrospinning method. Nanofiber patches were subjected to detailed analysis by scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). SEM results investigated that the morphology and diameter of nanofibers were affected by the concentration of lanolin in silk fibroin. Incorporating Lanolin into SF nanofibers improved the mechanical properties of the SF/PCL/Lanolin nanofiber patches. Also, the cytotoxicity of samples was investigated through MTT assay, and the cell viability of samples shows toxicity to fibroblast cells. Experimental results showed that SF/PCL/Lanolin nanofiber patches did not show antibacterial activity nor their biocompatibility.

Polyvinyl alcohol nanofibrous membrane by high-curvature solid-needle electrospinning: Numerical simulation and experimental verification

Herein, polyvinyl alcohol nanofibrous membrane was fabricated firstly by the high-curvature solid-needle electrospinning. The influence of electrode curvature (needle angle), spinning voltage, solution concentration and collector distance on nanofiber morphology was systematically investigated numerically and experimentally. Numerical simulation shows that the electrical field increases with the increase of spinning voltage, while decreases with the increase of needle angle and collector distance. The experimental results are consistent with the numerical results. Furthermore, the solution concentration can be used to adjust the diameter of polyvinyl alcohol nanofibers. The possible applications of the nanofiber membrane to energy generation, water treatment, and separation are also discussed.

Influence of Electrospinning voltage on the Diameter and Properties of 1-dimensional Zinc Oxide Nanofiber

Influence of Electrospinning voltage on the Diameter and Properties of 1-dimensional Zinc Oxide Nanofiber

Construction of a myocardial patch with mesenchymal stem cells and poly(CL-co-TOSUO)/collagen scaffolds for myocardial infarction repair by coaxial electrospinning.

Stem cell cardiac patches have shown promising future for myocardium infarction (MI) therapy, but the characteristics of cardiac pulsation and tissue orientation lead to challenges in the design of cardiac repair scaffolds. Herein, a novel and multifunctional stem cell patch with favorable mechanical properties was reported. In this study, the scaffold was prepared by coaxial electrospinning of poly (CL-co-TOSUO)/collagen (PCT/collagen) core/shell nanofibers. Rat bone marrow-derived mesenchymal stem cells (MSCs) were seeded onto the scaffold to prepare the MSC patch. The nanofiber diameter of coaxial PCT/collagen was 945 ± 102 nm, and the tensile testing results showed that the PCT/collagen core/shell nanofibers possess highly elastic mechanical properties with an elongation at break higher than 300%. The results also showed that the MSCs maintained stem cell properties following seeding on the nano-fibers. The cells on the transplanted MSC patch survived 15 ± 4% 5 weeks following transplantation, and this PCT/collagen-MSC patch significantly improved the MI cardiac function and promoted angiogenesis. With high elasticity and good stem cell biocompatibility, the PCT/collagen core/shell nanofibers exhibited a good research value in the field of myocardial patches.

Investigation and multiscale modeling of PVA/SA coated poly lactic acid scaffold containing curcumin loaded layered double hydroxide nanohybrids.

Applying hydrophilic coatings on polymeric nanofibers combined with layered double hydroxide (LDH) not only enhances the efficiency of drug delivery systems but also increases cell adhesion. This work aimed to prepare poly(vinyl alcohol)/sodium alginate (PVA/SA) (2/1)-coated poly(lactic acid) (PLA) nanofibers containing curcumin-loaded layered double hydroxide (LDH) and to investigate their drug release and mechanical properties and their biocompatibility. The optimum PLA nanofibrous sample was considered to be that based on 3 wt% of curcumin-loaded LDH (PLA-3%LDH) with a drug encapsulation efficiency of ∼18% in which a minimum average nanofiber diameter of ∼476 nm along with a high tensile strength of 3.00 MPa were obtained. In the next step, a PVA/SA (2/1) layer was coated on the PLA-3%LDH; as a result, the hydrophilicity of the sample was improved and the elongation at break was decreased remarkably. In this regard the cell viability reached 80% for the coated PLA. Moreover, the formation of a layer of (PVA/SA) on the PLA nanofibers lowered the burst release and resulted in a more sustained drug release, which is a vital feature in dermal applications. A multiscale modeling method was applied for simulation of the mechanical properties of the composite scaffold and the results showed that this method can predict the data with 83% accuracy. The results of this study indicate that the formation of a layer of PVA/SA (2/1) has a significant effect on hydrophilicity and consequently improves cell adhesion and proliferation.

Electrospun PHBV nanofiber containing Tea Tree Oil: physicochemical and antimicrobial activity

Aiming to produce an antimicrobial dressing for wound healing applications, in this work Tea Tree oil (TTO) was incorporated into PHBV nanofibers by absorption. It was observed increase in the nanofiber diameter due to 5% TTO absorption efficiency, which also led to a 54% decrease in the contact angle. The releasing assay indicates a 6.8% oil release in the first 24 h – being probably the oil deposited at the polymer surface – followed by a minimal release at 48 h. The set of antimicrobial assays performed suggests the incorporation of TTO optimized the antimicrobial activity of the polymer for E. coli and C. albicans, while against S. aureus no significant difference was observed. The MTT assay showed no cytotoxicity of PHBV, but the incubation of L929 fibroblast cells with PHBV-TTO reduced cell viability. Overall, the PHBV nanofibers containing TTO present great potential as an antimicrobial dressing.

EMULSION ELECTROSPINNING OF PVA NANOFIBERS CONTAINING HYPERICUM PERFORATUM OIL

The aim of this study is to produce essential oil loaded nanofiber wound dressings from PVA, which is a biodegradable and biocompatible polymer, by emulsion electrospinning method. Hypericum Perforatum oil, known for its antibacterial, antioxidant and anti-inflammatory properties on skin disorders, was used and Kolliphor RH40 surfactant was added to emulsify oil in polymer solution. In order to examine the effect of surfactant amount on nanofiber morphology, surfactant was used at 2%, 4% and 6% (w/w) ratios. The effect of surfactant concentration on solution viscosity and fibre morphology were investigated by viscosity measurements and SEM analysis. To confirm the presence of Hypericum Perforatum oil in nanofibers structure FT-IR spectroscopy analysis were carried out. According to the results, the solution viscosity increased as the amount of surfactant increased. Additionally, it was observed that the average diameters of nanofibers, containing 2%, 4%, and 6% surfactant (w/w), increased compared to the pristine PVA nanofiber. In conclusion, the fiber morphology of Hypericum Perforatum oil-containing PVA nanofibers has been changed with the effect of surfactant.

Self-assembly of Dendrimer-DNA amphiphiles and their catalysis as G-quadruplex/hemin DNAzymes

Nanomaterials self-assembled by DNA amphiphiles have great potential application in catalysis, bioimaging and biomedicine. Here, we constructed two kinds of DNA-dendrimer amphiphiles including the G-quadruplex-dendrimer hybrid (G20-Den) and single-stranded DNA-dendrimer hybrid (D20-Den) as a control. Both of them self-assembled into nanofibers with a length of several micrometers in MES buffer, and the diameter of G20-Den nanofibers was smaller than that of D20-Den nanofibers due to the compact stacking of G-quadruplex formed in G20-Den hybrids. At the same time, the catalytic properties of G20-Den nanofiber/hemin, as horseradish peroxidase-mimicking DNAzymes, were investigated. Our results showed that G20-Den nanofiber/hemin, as well as the single-stranded G20/hemin system, exhibited higher catalytic peroxidation activity than D20-Den nanofiber/hemin. Furthermore, through simple ultrafiltration, the recycle of these nanofibers can be simply achieved. This research has provided a new solution for the construction of functional DNA nanomaterials.

Design and fabrication of polyvinylidene fluoride-graphene oxide/gelatine nanofibrous scaffold for cardiac tissue engineering

Polyvinylidene fluoride (PVDF) electrospun scaffolds have recently been developed for cardiac tissue engineering applications thanks to their piezoelectricity. However, PVDFs’ hydrophobic nature requires modifications by incorporating natural polymers. In this study, we focussed on the hybrid electrospinning of PVDF and gelatine and the further introduction of graphene oxide nanoparticles to investigate either hydrophilicity or piezoelectricity enhancement and its impact on mouse embryonic cardiomyocytes. The results revealed a nanofibre diameter of 379 ± 73 nm for the PVDF/gelatine/graphene oxide (PVDF-GO-CG) platform, providing excellent tensile strength. Additionally, hydrophilicity was improved by gelatine and GO incorporation compared with pure PVDF. Cellular studies also showed an elongated morphology of cardiomyocytes, similar to the myocardial tissue, as well as high viability and non-toxicity in the PVDF-GO-CG scaffold according to the average survival rate. Furthermore, the expression of connexin 43 and troponin T genes underwent an increment of 41 and 35% in the PVDF-GO-CG compared with the PVDF-CG sample. This study proves the applicability of the PVDF-GO-CG scaffold as an alternative substrate for developing engineered cardiac tissues by providing an environment to re-establish their synchronised communications.

The Effect of Electrospinning Parameters on Piezoelectric PVDF-TrFE Nanofibers: Experimental and Simulation Study

Polyvinylidene fluoride and its copolymers can be used as active materials for energy harvesting and environmental sensing. Energy harvesting is one of the most recent research techniques for producing stable electrical energy from mechanical sources. Polyvinylidene fluoride–trifluoroethylene (PVDF-TrFE) is applicable for sensors and self-powered devices such as medical implants and wearable electronic devices. The preparation of electrospun P(VDF-TrFE) nanofibers is of great interest for the fabrication of sensors and self-powered devices, nanogenerators, and sensors. In this regard, it is necessary to investigate the effects of various parameters on the morphology and piezoelectric output voltage of such nanofibers. In this study, we have examined the effect of concentration and feed rate on the nanofiber diameter. It has been found that by increasing the concentration and feed rate of the polymer solution, the diameter of the nanofibers increases. The experimental results and the finite element method (FEM) simulation have also shown consistency; when the nanofiber diameter increases, the output voltage of the nanofibers decreases. This behavior can be related to the strain reduction in the deformed nanofibers.

Electrospinning of ZrO2 fibers without sol-gel methods: Effect of inorganic Zr-source on electrospinning properties and phase composition

The aim of this study was the electrospinning of zirconia nanofibers without sol-gel precursors. Low-cost Zr-oxide and Zr-carbonate inorganic materials, with high molecular Zr-content compared to sol-gel methods, were used for precursor formulation. Using a polyvinylpyrrolidone (PVP) polymeric binder, zirconia nanofibers could successfully be synthesised with both Zr-sources. The effects of different electrospinning parameters were investigated to stabilize the processing and reduce the deviation of nanofiber diameters. Fibres calcined at 1000 °C produced from the two different precursors displayed differing crystal phases of zirconia. The one based on nanoparticles revealed a significantly higher amount of tetragonal phase. Zirconia nanofibers with poly-granular microstructure across the diameter were successfully produced.

Effect of Cross-Linking and Surface Treatment on the Functional Properties of Electrospun Polybenzimidazole Separators for Lithium Metal Batteries.

In this work, electrospun PBI separators with a highly porous structure and nanofiber diameter of about 90-150 nm are prepared using a multi-nozzle under controlled conditions for lithium metal batteries. Cross-linking with α, α-dibromo-p-xylene and surface treatment using 4-(chloromethyl) benzoic acid successfully improve the electrochemical as well as mechanical properties of the separators. The resulting separator is endowed with high thermal stability and excellent wettability (1080 to 1150%) with commercial liquid electrolyte than PE and PP (Celgard 2400) separators. Besides, attractive cycling stability and rate capability in LiFePO4/Li cells are attained with the modified separators. Prominently, CROSSLINK PBI exhibits a stable Coulombic efficiency of more than 99% over 100 charge-discharge cycles at 0.5 C, which is superior to the value of cells using commercial PE and PP (Celgard 2400) separators. The half cells assembled using the CROSSLINK PBI separator can deliver a discharge capacity of 150.3 mAh g-1 at 0.2 C after 50 cycles corresponding to 88.4% of the theoretical value of LiFePO4 (170 mAh g-1). This work offers a worthwhile method to produce thermally stable separators with noteworthy electrochemical performances which opens new possibilities to improve the safe operation of batteries.

Lawsonia inermis-loaded poly (L-lactide-co-D, L-lactide) nanofibers for healing acceleration of burn wounds

This study aimed to develop a new bioactive wound dressing based on electrospun poly (L-lactide-co-D, L-lactide) (PLDLLA) nanofibers containing Lawsonia inermis (LI) for burn wounds. The SEM results showed that loading LI increased the average diameter of PLDLLA nanofibers to 528 nm with smooth and beadless morphology. The analysis of LI release from PLDLLA nanofibers and film samples was measured by UV-vis spectrophotometry, and the obtained results revealed that LI molecules could diffuse from the nanofibrous sample with higher rate than film during 48 h. In this regard, the PLDLLA nanofibrous sample as a drug carrier has advantages compared to the film. Moreover, the antibacterial results confirmed the positive influence of LI related to the bacteria which in turn the growth inhibition zones were increased from 6 to 22 mm for P. aeruginosa, and from 3 to 16 mm for S. aureus while the LI concentration was set at 1.4% (w/v). Finally, animal model studies demonstrated that PLDLLA-LI nanofibers accelerated burn wound closure remarkably; thereby decreasing the wound area approximately 90% during the treatment period of 19 days. The histological observations dedicated that the appearance of the epithelial layer was increased dramatically alongside the thickness of around 40% for the wound treated with PLDLLA-LI nanofibrous sample rather than that without LI. Besides the epithelialization, it has been found that the wound covered by PLDLLA-LI wound dressing has condensed collagen fibers with no necrosis.

High-efficiency retention of ultrafine aerosols by electrospun nanofibers

The versatility of nanofibrous polymeric materials makes them attractive for developing respiratory protective equipment. Ultrafine nanofibers effectively trap the most penetrating aerosols and exhibit consistent performance compared to conventional electret filters. Advanced nanofiber manufacturing technologies such as electrospinning can functionalize filter materials, enhancing them with unique antibacterial, catalytic, sensory, and other properties. Much of the current research in nanofibrous air filtration focuses on using nanofibers for lightweight personal protective equipment such as N95 respirators, but their use for higher levels of respiratory protection required for chemical, biological, radiological, and nuclear (CBRN) protection has not yet been comprehensively explored. In this study, we tested the hypothesis that electrospun filters could provide the particle filtration efficiency and breathing resistance required by the National Institute for Occupational Safety and Health Standard for CBRN air-purifying respirators. Our manufactured nanofibrous filters demonstrated submicron aerosol retention efficiency of > 99.999999%, which is four orders of magnitude better than the requirements of the CBRN standard. They also had a breathing resistance of ~ 26 mmH2O, which is more than twofold lower than the maximum allowable limit. Although the filter material from the gas mask cartridge currently in service with the U.S. military demonstrated a higher quality factor than electrospun filters, the comparative analysis of filter morphology suggested ways of improving nanofibrous filter performance by tuning nanofiber diameter distribution.