Electrospinning Academic News

Enhanced Performance of High Energy Density Lithium Metal Battery with PVDF-HFP/LAGP Composite Separator 2021-03-17

The development of high energy density lithium ion batteries puts forward requirements for separators. In this article, poly(vinylidenefluoride-hexafluoropropylene)/Li1.5Al0.5Ge1.5(PO4)3 composite membrane (PL) has been fabricated by electrospinning and with use of the dip-coating method as the separator of the lithium ion battery. With reference to the physical properties, PL has better mechanical strength than does its base membrane electrospun poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP), and thermal stability and electrolyte uptake (215%) higher than those of the PP separator; with reference to the electrochemistry parameters, PL has an ionic conductivity of up to 3.18 mS cm–1 at RT and a wide electrochemical window of 5.3 V (vs Li+/Li). The NCM811||Li battery that uses the PL separator exhibits a longer cycle life (144.7 mAh g–1 after 500 cycles at 0.2 C), a lower interfacial resistance change (71.19 Ω), and a higher rate capability as compared to the batteries that us

Fabrication of Carbon Nanofibers Decorated with Various Kinds of Metal Oxides for Battery Applications 2021-03-17

Carbon nanofibers decorated with various metal oxide nanoparticles were fabricated by combining an electrospinning technique of bicomponent polymer mixture and a sol-gel reaction and subsequent carbonization process. Electrospun polymer nanofibers consisting of polyacrylonitrile (PAN) and poly(vinyl pyrrolidone) (PVP) with controllable diameters were fabricated with PAN/PVP core/shell types via phase-separation due to the immiscibility between two polymers. The electrospun nanofibers served as supporting materials with binding sites of PVP to incorporate titanium oxide precursor. Subsequently, the carbonization of the fibers led to the formation of carbon nanofibers@TiO2 for energy application, in which rutile TiO2 nanoparticles were decorated on the surface of carbon nanofiber. Especially, this TiO2 decorated carbon nanofiber electrode exhibited excellent electrochemical property in lithium-ion batteries (≈600 mA h g−1 at C/5 rate for 100 cycles). Furthermore, the carbon nanofibers we

Sesamol incorporated cellulose acetate-zein composite nanofiber membrane: An efficient strategy to accelerate diabetic wound healing 2021-03-16

Recently, the function of nanofiber membranes prepared from electrospinning in accelerating wound healing has attracted wide attention. In this study, novel nanofiber membranes consisted of cellulose acetate (CA) and zein were fabricated to provide efficient delivery vehicles for sesamol, and then the effect of sesamol-loaded composite nanofiber membranes on the wound healing of diabetic mice was studied. It was found the critical concentration of CA was between 15% and 25% (w/v), and the most suitable concentration of stabilizing fibers was 22.5%. When the CA/zein ratio was 12:8, the fiber obtained small diameter and uniform distribution, stable intermolecular structure, low infiltration speed and high stability in water. The composite nanofiber membrane with high-dose sesamol (5% of total polymer concentration, w/w) promoted formation of myofibroblasts by enhancing TGF-β signaling pathway transduction, and promoted keratinocyte growth by inhibiting chronic inflammation in wounds, thu

Upregulating Hif‐1α by Hydrogel Nanofibrous Scaffolds for Rapidly Recruiting Angiogenesis Relative Cells in Diabetic Wound 2021-03-16

Nonhealing chronic wounds on foot are one of the most dreaded complications of diabetes, and biomedical scaffolds remain an attractive option for repairing or regenerating tissues. Accelerating angiogenesis in the early stage after injury is critical to wound healing process; however, the scaffolds accelerate the angiogenesis in the beginning but with the acceleration of vessel network formation the scaffold network hinders the process. In this study, the water soluble drugs‐loaded hydrogel nanofibrous scaffolds are designed for rapidly recruiting angiogenesis relative cells and promoting wound healing. The sustained release profile of desferrioxamine (DFO), which continues for about 72 h, leads to significantly increase of neovascularization. The majority of the scaffold is degraded in 14 d, leaving enough space for cell proliferation and vessel formation. The in vitro results show that the scaffolds upregulate the expression of Hif‐1α and vascular endothelial growth factor, and enhan

Antibacterial efficacy of quaternized chitosan/poly (vinyl alcohol) nanofiber membrane crosslinked with blocked diisocyanate 2021-03-16

N-[(2-hydroxyl-3-trimethylammonium) propyl] chitosan chloride (HTCC), which is a type of chitosan derivative with quaternary ammonium groups, possesses a higher antibacterial activity as compared to the pristine chitosan. The nanofiber membranes made of HTCC are attractive for applications demanding for antibacterial function. However, the hydrophilic nature of HTCC makes it unsuitable for electrospinning of nanofibers. Hence, biodegradable polyvinyl alcohol (PVA) was proposed as an additive to improve the electrospinnability of HTCC. In this work, PVA/HTCC nanofiber membrane was crosslinked with the blocked diisocyanate (BI) to enhance the stability of nanofiber membrane in water. Microbiological assessments showed that the PVA/HTCC/BI nanofiber membranes possessed a good antibacterial efficacy (∼100 %) against E. coli. Moreover, the biocompatibility of PVA/HTCC/BI nanofiber membrane was proven by the cytotoxicity test on mouse fibroblasts. These promising results indicated that the P

In-situ electrospinning of thymol-loaded polyurethane fibrous membranes for waterproof, breathable, and antibacterial wound dressing application 2021-03-16

Skin-like flexible membrane with excellent water resistance and moisture permeability is an urgent need in the wound dressing field to provide comfort and protection for the wound site. Despite efforts that have been made in the development of waterproof and breathable (W&B) membranes, the in-situ electrospinning of W&B membranes suitable for irregular wound surfaces as wound dressings still faces huge challenges. In the current work, a portable electrospinning device with multi-functions, including adjustable perfusion speed for a large range from 0.05 mL/h to 10 mL/h and high voltage up to 11 kV, was designed. The thymol-loaded ethanol-soluble polyurethane (EPU) skin-like W&B nanofibrous membranes with antibacterial activity were fabricated via the custom-designed device. Ultimately, the resultant nanofibrous membranes composed of EPU, fluorinated polyurethane (FPU), and thymol presented uniform structure, robust waterproofness with the hydrostatic pressure of 17.6 cm H2O, excellent

Preparation and performance evaluation of tetracycline hydrochloride loaded wound dressing mats based on electrospun nanofibrous poly(lactic acid)/poly(ϵ‐caprolactone) blends 2021-03-16

In this article, we present the drug‐release rate, water uptake, water permeability, morphology, and mechanical properties of a series of active wound dressing nanofibrous mats prepared via an electrospinning process of poly(lactic acid) (PLA), poly(ϵ‐caprolactone) (PCL), and their (50/50) blends loaded with different doses of tetracycline hydrochloride antibiotic. The performance of these active wound dressings in terms of a sustained and suitable drug‐release rate, adequate water uptake and water permeability, and antibacterial activities were compared with those of a commercial wound dressing (Comfeel Plus). The results show that the dressings made from PCL and PLA/PCL blends showed better performance compared with the commercial wound dressing sample as far as these properties were concerned. The improved performance could be explained on the basis of the nanofibrous structure of the mats and the hydrophilicity of PCL and PLA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Efficient preparation of poly(lactic acid) nanofibers by melt differential electrospinning with addition of acetyl tributyl citrate 2021-03-16

Poly(lactic acid) (PLA) nanofibers, as a biodegradable and environmentally friendly material, have potential applications such as biological medicine, efficient filter material, and so on. PLA nanofibers are usually prepared by solution electrospinning method with toxic solvents, such as chloroform, chloromethane, and N,N‐dimethyl formamide. In this work, PLA nanofibers were fabricated with a self‐designed melt differential electrospinning device, assisted by addition of nontoxic acetyl tributyl citrate (ATBC) and by airflow. Molecular dynamics simulations were performed to understand the experimental results. The results revealed that the fiber diameter decreased with increasing airflow velocity, and fibers with a diameter as small as 236 nm were obtained at the highest airflow velocity of 25 m/s (with 6 wt % of ATBC). Furthermore, a significantly accelerated falling speed of the jets of about 347 times of that without airflow was achieved at a flow rate of 25 m/s. These results demon

A review of key challenges of electrospun scaffolds for tissue‐engineering applications 2021-03-16

Tissue engineering holds great promise to develop functional constructs resembling the structural organization of native tissues to improve or replace biological functions, with the ultimate goal of avoiding organ transplantation. In tissue engineering, cells are often seeded into artificial structures capable of supporting three‐dimensional (3D) tissue formation. An optimal scaffold for tissue‐engineering applications should mimic the mechanical and functional properties of the extracellular matrix (ECM) of those tissues to be regenerated. Amongst the various scaffolding techniques, electrospinning is an outstanding one which is capable of producing non‐woven fibrous structures with dimensional constituents similar to those of ECM fibres. In recent years, electrospinning has gained widespread interest as a potential tissue‐engineering scaffolding technique and has been discussed in detail in many studies. So why this review? Apart from their clear advantages and extensive use, electro

A review on wound dressings with an emphasis on electrospun nanofibrous polymeric bandages 2021-03-16

Wound dressings have experienced continuous and significant changes since the ancient times. The development starts with the use of natural materials to simply cover the wounds to the materials of the present time that could be specially made to exhibit various extraordinary functions. The modern bandage materials made of electrospun biopolymers contain various active compounds that are beneficial to the healing of wounds. These materials are fibrous in nature, with the size of fibers segments ranging from tens of nanometers to micrometers. With the right choices of biopolymers used for these fibrous materials, they could enhance the healing of wounds significantly compared with the conventional fibrous dressing materials, such as gauze. These bandages could be made such that they contain bioactive ingredients, such as antimicrobial, antibacterial, and anti‐inflammatory agents, which could be released to the wounds enhancing their healing. In an active wound dressing (AWD), the main pu

Effect of surface chemistry‐modified polycaprolactone scaffolds on osteogenic differentiation of stem cells from human exfoliated deciduous teeth 2021-03-16

The aim of this study was to investigate the effect of surface modification of a polycaprolactone scaffold on promoting osteogenic differentiation of stem cells from human exfoliated deciduous teeth. Four different polycaprolactone scaffold were evaluated: untreated; coated with hyaluronic acid; coated with gelatin; and coated with hyaluronic acid and then with gelatin. The resulting scaffolds were characterized using scanning electron microscopy and attenuated total reflectance‐Fourier transform infrared spectroscopy (ATR‐FTIR). Human stem cells were cultured on the modified scaffolds placed in osteogenic differentiation medium. During culture, the osteogenic potential of the stem cells was examined by evaluating alkaline phosphatase activity and staining intensity, expression of osteoblastic‐specific genes, and matrix mineralization. Scanning electron microscopy and ATR‐FTIR confirmed productive biomacromolecular surface treatment of the polycaprolactone scaffold. All scaffolds permi

ELECTROSPUN NANOFIBERS FOR ENZYME IMMOBILIZATION 2021-03-16

An enzyme is a kind of protein with a catalytic function. As a biological catalyst it has many merits,including a quick reaction rate, mild reaction conditions, and strong substrate specifificity, and the enzyme itself can be degraded by microorganisms, so it meets the requirements of green chemistry. Thus enzymes have been widely applied in various fifields, such as food, medicine, light industry, agriculture, etc. Nevertheless, the advanced structure of the enzyme renders it very sensitive to environmental conditions, like pH, temperature, metal ions, and organic solvents. Changes in these environmental conditions may lead to a loss of activity in free enzymes. Moreover, free enzymes cannot be recycled after a reaction and have no reutilization, which restrict practical applications. Hence enzyme immobilization techniques provide broad prospects for the application of enzymes .

Academic News