Electrospun Nanofibrous Membranes Research Articles

Electrospun antibacterial poly(vinyl alcohol)/Ag nanoparticles membrane grafted with 3,3′,4,4′-benzophenone tetracarboxylic acid for efficient air filtration

In this study, poly(vinyl alcohol) (PVA) membranes containing Ag nanoparticles (AgNPs) were prepared by electrospinning and grafted copolymerization with 3,3′,4,4′-benzophenone tetracarboxylic acid (BPTA) to provide better mechanical properties, lower water vapor transmittance, and higher antibacterial activity (against Staphylococcus aureus and Escherichia coli) than the PVA/AgNPs membrane. The PVA/AgNPs/BPTA membrane showed higher antibacterial activity than the other membranes, and it produced inhibition zones with diameters of 18.12 ± 0.08 and 16.41 ± 0.05 mm against S. aureus and E. coli, respectively. The PVA/AgNPs/BPTA membrane was found to be capable of promoting reactive oxygen species (ROS) formation under both light and dark conditions. Cycling experiments performed following ROS quenching showed that the best-performing composite membrane retained >70% of its original OH⋅ radical and H2O2 charging capacity after seven cycles. In the filtration test, the electrospun nanofibrous membranes showed high filtration efficiencies of 99.98% for sodium chloride (NaCl). In addition, these membranes maintained a relatively low pressure drop of 168 Pa with a basis weight of 2.1 g m−2. Thus, the PVA/AgNPs/BPTA membrane was concluded to be a promising medical protective material offering the benefits of structural stability and reusability.

Adsorption of methylene blue onto electrospun nanofibrous membranes of polylactic acid and polyacrylonitrile coated with chloride doped polyaniline

This study presents the preparation of membranes of polylactic acid (PLLA), polyacrylonitrile (PAN) and their corresponding membranes coated with polyaniline (PANI) for the adsorption of methylene blue (MB). Scanning electron microscopy micrographs reveal that all the membranes exhibit nanofibrous morphology. The adsorption capacity and the removal efficiency of the membranes are studied as a function of (initial adsorbate concentration, pH of the medium, temperature, contact time and adsorbent dosage). Coated membranes with PANI showed better adsorption performance and their DC conductivities were correlated to MB concentrations. Adsorption isotherms have also been performed and the adsorption process has been tested according to Langmuir and Freundlich models. The regeneration and reuse of the prepared membranes to re-adsorb MB were also investigated. The enhancement in adsorption performance and reusability of PANI-coated membranes in comparison with non-coated ones are fully discussed.

Tuning the synthetic conditions of graphene oxide/magnetite/ hydroxyapatite/cellulose acetate nanofibrous membranes for removing Cr(VI), Se(IV) and methylene blue from aqueous solutions

The discharge of high toxic contaminations of heavy metals and dyes to water resources has posed severe problems for the eco-system and human health. In this work, electrospun nanofibrous membranes of cellulose acetate containing fillers of graphene oxide (GO), magnetite nanoparticles (MNPs) or hydroxyapatite (HAP) were fabricated. It was shown that the membranes were configured in randomly oriented fibers with diameters around 0.11−0.35 μm and 0.66–1.23 μm, 0.14−0.33 μm and 0.6−0.89 μm, 0.17−0.37 μm and 0.91–4.57 μm 0.18−0.53 μm and 1.18–2.1 μm and 0.11−0.29 μm for CA, GO@CA, MNPs@CA, HAP@CA and GO/MNPs/HAP@CA, respectively. The observed surface roughness tends to be promoted upon supplementations, as the roughness average (Ra) increased from 31.3 nm to 52 nm for CA and GO/MNPs/HAP@CA, respectively. The estimated toughness indicated that values increased from pristine CA reaching to its highest one at MNPs@CA as 2.5 ± 0.2 MJ/m3 to 8.2 ± 0.5 MJ/m3, respectively. The Se(IV) and Cr(VI) removal from aqueous solutions using the nanofibrous membranes was examined upon the time and pH value of the media. The removal efficiency for Se(IV) has improved from 89.3 % at pH 4–96 % for GO/MNPs/HAP@CA. Moreover, Cr(VI) removal progressed from 86.7, 86.3, 89.9, 90.6 and 92.9 % at pH 4–89.8, 90.5, 94.1, 94.7 and 97.3 % at pH 8 for CA, GO@CA, MNPs@CA, HAP@CA and GO/MNPs/HAP@CA, respectively. The degradation of methylene blue (MB) was investigated and reached its highest value of 95.1 % for GO/MNPs/HAP@CA after 35 min of continuous irradiation under visible light.

Gamma-phase CsPbBr3 perovskite nanocrystals/polymethyl methacrylate electrospun nanofibrous membranes with superior photo-catalytic property

Gamma-phase cesium lead tri-bromide perovskite nanocrystals (γ-CsPbBr3 NCs) possess potentially photo-catalytic degradation ability and long-term stability. However, their serious aggregation issue decreases their active surface area, and the recombination of photo-generated hole-electron pairs weakens their photo-catalytic property. Furthermore, these NCs can be easily absorbed on the surface of dyes [e.g., methylene blue (MB)] or dissolved in the dye solution during the photo-catalytic degradation process, thus reducing the amount of γ-CsPbBr3 NCs and their photo-catalytic degradation ability. Besides, the residual γ-CsPbBr3 NCs in the photo-catalytic degradation products also present the toxicity issue (containing Pb) and are hazardous to the ecological environment and human health. In the present study, we fabricated γ-CsPbBr3 NCs/polymethyl methacrylate electrospun nanofibrous membranes (γ-CsPbBr3 NCs/PMMA ENMs) by using electrospinning technology to solve the above problems. It is found that the synthesized γ-CsPbBr3 NCs/PMMA ENMs show a large surface area and the abundant functional groups on their surfaces, which are benefit for forming multiple kinds of chemical bonding effect between γ-CsPbBr3 NCs and PMMA ENMs. In addition, γ-CsPbBr3 NCs could disperse homogeneously in or on the surface of PMMA ENMs. These abundant chemical bonds and homogeneous distributions of γ-CsPbBr3 NCs on the surface of PMMA ENMs can significantly decrease the recombination of photo-generated hole-electron pairs and toxicity issue of γ-CsPbBr3 NCs during the photo-catalytic degradation process. Exhilaratingly, γ-CsPbBr3 NCs/PMMA ENMs could maintain a superior photo-catalytic degradation ability toward various dyes and reveal a high photo-catalytic degradation efficiency of 99.18% in 60 min for MB.

Super hygroscopic nanofibrous membrane-based moisture pump for solar-driven indoor dehumidification

Desiccants play vital roles in dehumidification and atmospheric water harvesting; however, current desiccants have mediocre hygroscopicity, limited recyclability, and high energy consumption. Herein, we report a wood-inspired moisture pump based on electrospun nanofibrous membrane for solar-driven continuous indoor dehumidification. The developed moisture pump with multilayer wood-like cellular networks and interconnected open channels is composed of a desiccant layer and a photothermal layer. The desiccant layer exhibits an unprecedented moisture absorption capacity of 3.01 g g−1 at 90% relative humidity (RH), fast moisture absorption and transport rates, enabling atmospheric water harvesting. The photothermal layer shows a high solar absorption of 93%, efficient solar thermal conversion, and good moisture permeability, thus promoting water evaporation. The moisture pump efficiently reduces the indoor relative humidity to a comfort level (40‒60% RH) under one-sun illumination. This work opens the way to develop new-generation, high-performance nanofibrous membrane-based desiccants for energy-efficient humidity control and atmospheric water harvesting.

A promising approach toward efficient isolation of the exosomes by core-shell PCL-gelatin electrospun nanofibers.

Exosomes as cell-derived vesicles are promising biomarkers for noninvasive and early detection of different types of cancer. However, a straightforward and cost-effective technique for isolation of exosomes in routine clinical settings is still challenging. Herein, we present for the first time, a novel coaxial nanofiber structure for the exosome isolation from body fluids with high efficiency. Coaxial nanofiber structure is composed of polycaprolactone polymer as core and a thin layer of gelatin (below 10nm) as the shell. The thermo-sensitive thin layer of gelatin can efficiently release the captured exosome by specific antibody namely, CD63, whenever its temperature raised to the physiological temperature of 37°C. Moreover, the thin layer of gelatin induces less contamination to separated exosomes. The interconnected micro-pores of electrospun nanofibrous membrane insurances large surface area for immobilization of specific antibody for efficient exosome capturing. The efficacy of exosome isolation is determined by direct ELISA and compared with ultracentrifugation technique. For the exosome isolation, it was observed that over 87% of exosomes existed in the culture medium can be effectively isolated by coaxial electrospun nanofibers with the average thickness of 50µm. Therefore, this promising technique can be substituted for the traditional techniques for exosome isolation which are mostly suffering from low efficacy, high cost, and troublesome process.

Engineering highly effective nanofibrous membranes to demulsify surfactant-stabilized oil-in-water emulsions

Demulsification of oil-in-water emulsions is challenging but significant for oily wastewater treatment, especially for surfactant-stabilized oil-in-water (S–O/W) emulsions. Electrospun nanofibrous membranes exhibit promising performance as demulsification medium but the underline mechanisms are still unclear. In this work, the effects of membrane pore size and nanofiber surface wettability on the demulsification of the S–O/W emulsions were investigated. Two polyvinylidene difluoride (PVDF) nanofibrous membranes with different nanofiber diameter (#P2: 200 nm and #P10: 1000 nm) were developed by electrospinning. The superhydrophilic membranes (#Dopa-P2 and #Dopa-P10) were obtained by coating polydopamine layers on both membranes #P2 and #P10. The silver nanoparticle deposition and subsequent fluorination were conducted on the surfaces of the polydopamine-activated membranes to prepare superhydrophobic nanofibrous membranes (#Ag–P2 and #Ag–P10). The superhydrophilic membrane #Dopa-P10 with a membrane pore size matching the oil droplets performed the best demulsification result. The oil droplets size increased up to 15 times (from 6.5 ± 1.0 μm to 98 ± 7 μm) after passing through #Dopa-P10. The underlying mechanism should be the superhydrophilic nanofibers possessed excellent affinity to the surfactants layer surrounding oil droplets, which could destroy the stable status and facilitate the coalescence of the oil droplets in S–O/W emulsions. The hydrophobic and superhydrophobic membrane #P10 and #Ag–P10 showed little coalescence effects as they exhibited a negative repulsive force to oil droplets. The physical cutting effect dominated the coalescence process when oil droplets passing through the membranes (#P2, #Dopa-P2, and #Ag–P2) with pore size much smaller than oil droplets. The various surface wettability didn't show any obvious difference on the coalescence results.

Characterization of electrospun polylactide nanofibers modified via atom transfer radical polymerization

Polylactic acid-based membranes received considerable attention due to its novel biocompatibility, renewability, and biodegradability. In this study, PLA electrospun nanofibrous membrane was prepared and 2-dimethylaminoethyl methacrylate (DMAEMA) was used as a monomer for surface grafting of polymer chains via the atom transfer radical polymerization method. Then the PLA nanofibers were quaternized by using bromoethane. The characterization of poly(DMAEMA) graft PLA nanofiber (poly(DMAEMA)-g-PLA) membranes was done by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and energy dispersive X-ray spectroscopy. The results showed that the diameter of PLA nanofibers increased 15% as the concentration increased from 10% to 12% and then increased 23% as the concentration of PLA solution increased from 10% to 15%. But the regularity of average diameters is best achieved at 12% concentration.

Application of electrospun nanofibrous amphiphobic membrane using low-cost poly (ethylene terephthalate) for robust membrane distillation

Although with great potential, membrane distillation (MD) is still far from satisfaction due to deficiency of ideal membranes with low cost and high performance. In this work, electrospun nanofibrous membranes (ENMs) fabricated using polyethylene terephthalate (PET) derived from recycled Coca Cola plastic bottles were evaluated in direct contact (DC) MD application. Heat-pressing was used to tune physicochemical properties of PET ENMs to get them better qualified for MD. Effect of heat-pressing on membrane structure and properties was emphasized. The preferred PET ENMs with nanofiber diameter of 517 nm exhibited high porosity of 77 %, high hydrophobicity with contact angle of ≥130°, and high liquid entry pressure of water (LEPw) of 49.8 kPa. The optimized PET ENMs displayed permeation of about 11−23 L m−2 h-1 (LMH) with varied temperature differences and salt rejection of 99.9 %. Stable permeation was noticed in the long-run membrane operation without significant permeation loss. Finally, 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (FAS) was used to modify the surface of membrane to enhance their antiwetting capability against the oil. Surface modification rendered excellent endurance to the membrane even with addition of 0.3 M Sodium Dodecyl Sulfate (SDS, a model surfactant) while the pristine membrane failed to work once the SDS was added. This work paves the way for developing a low-cost and acceptable industrial-grade membrane with great potential in DCMD applications.

Copper//terbium dual metal organic frameworks incorporated side-by-side electrospun nanofibrous membrane: A novel tactics for an efficient adsorption of particulate matter and luminescence property

Particulate matters with different sizes (PM2.5 and PM10) in the air have become a supreme environmental concern to human health globally. Herein, the magnetic-luminescent Cu//Tb dual metal-organic frameworks (MOFs) incorporated side-by-side nanofibrous (SBS-NFs) membrane has been successfully fabricated via the electrospinning technique with the self-designed nozzle for the first time. The fabricated SBS-NFs membrane was composed of Cu-MOF/PAN at one side and Tb-MOF/PAN at another side with their individual characteristics. The Cu-MOF was used to improve the filtration efficiency and reduced the pressure drop by enhancing the electrostatic interaction, whereas, Tb-MOF was incorporated to investigate the PM adsorption process through the changes in luminescence intensity. Compared to polyacrylonitrile nanofibers (PAN NFs), Cu//Tb dual MOFs incorporated SBS-NFs membrane showed an enhanced filtration efficiency (90.2%) and a reduced pressure drop (60.7 Pa) when sodium chloride (NaCl) aerosols with particle size less than 300 nm were used for testing. As a result of the filter test using car exhaust, Cu//Tb SBS-NFs membrane still maintained >91% PM removal efficiency for >30 h. In addition, it was confirmed that the luminescence intensity over the PM adsorption time was linearly weakened. Therefore, Cu//Tb dual MOFs incorporated SBS-NFs membrane can be used for a variety of applications.

Scalable, flexible and reusable graphene oxide-functionalized electrospun nanofibrous membrane for solar photothermal desalination

Solar photothermal desalination of seawater has become a novel, efficient and feasible solution for the scarcity of water. Its efficiency mainly depends on the properties of photothermal conversion materials. Herein, graphene oxide functionalized polyvinyl alcohol EFMs (GO/PVA EFMs) were developed as the photothermal conversion material by blend electrospinning. The GO/PVA EFMs are composed of uniform nanofibers, with GO immobilized in the fibers as photo absorption component. The photothermal conversion properties of GO/PVA EFMs were closely related to the GO concentration. The evaporation rate of GO/PVA EFMs with 5% of GO concentration for pure water could reach up to 1.40 kg m−2 h−1 under 1 sun (1 kW m−2) irradiation, and the energy conversion efficiency was as high as 90.0%. For the simulated seawater, their optimal evaporation rate could achieve 1.42 kg m−2 h−1, and the corresponding energy conversion efficiency was up to 94.2%. After using the GO/PVA EFMs-5% for the desalination of actual seawater from Yellow Sea, the concentrations of five primary ions in the purified water are around 1 mg L−1, which were far below the limit of drinking water recommended by the World Health Organization. The GO/PVA EFMs possess excellent photothermal desalination efficiency, it is because that the extremely hydrophilicity could ensure continuous water supply, the uniformly distributed GO in the fibers could achieve effective photo absorption and photothermal conversion, the porous non-woven structure could provisionally confine heat energy to facilitate liquid water become water vapor, and the abundant mesoporous channels could promote the flow and escape of water vapor. More importantly, the GO/PVA EFMs possess excellent stability in harsh environments such as strong acid and alkalis, high concentration brine and long-term photothermal evaporation, and also have good durability and reusability. Therefore, GO/PVA EFMs are the promising materials for long-term and practical applications in solar photothermal desalination.

Metal-organic framework/poly (ε-caprolactone) hybrid electrospun nanofibrous membranes with effective photodynamic antibacterial activities

Functionalization of electrospun mats with antimicrobial nanomaterials is an attractive strategy to prevent bacterial colonization and accelerate infected wound healing. Compared with the traditional antibacterial strategies relying on bactericides, photodynamic antimicrobial therapy (PDT) has received considerable attentions owing to its high efficiency and controllability. Herein, we demonstrated a feasible approach to produce antimicrobial electrospun mats through co-electrospinning of biodegradable PCL matrix and photosensitive metal-organic framework (MOF) nanocrystals. Briefly, rose bengal (RB) was one-step encapsulated into zeolitic imidazolate framework-8 (ZIF-8) to obtain photodynamic antimicrobial RB@ZIF-8 nanoparticles, followed by blended with PCL matrix to yield composited polymeric nanofibers via co-electrospun. By adjusting the contents of RB@ZIF-8 in PCL, sufficient MOF particles were presented on the nanofiber surfaces. Benefited from the reactive oxygen species (ROS) generation upon visible light irradiation, the nanofibrous membranes were able to dose and time-dependent inactivate of Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) in vitro. Besides, the nanofibrous showed considerable low hemolysis activities. Moreover, a bacteria-infected wound healing experiment suggested that the nanofibrous membrane had a better ability to remedy bacteria wound infection and accelerate wound healing. This work would greatly expand the bioapplications of MOF materials and may assist in developing novel hybrid materials with the ability to hinder microbial infections.

Poly (ether) sulfone electrospun nanofibrous membranes embedded with graphene oxide quantum dots with antimicrobial activity.

This work describes the development of novel electrospun nanofibrous membranes (ENMs) prepared by embedding graphene oxide quantum dots (GOQDs) into poly (ether) sulfone (PES). FTIR and Raman spectroscopy confirmed the successful incorporation of the GOQDs into the PES membranes. The optimal electrospinning polymer concentration that showed no defects or bead formation was at 26wt% of the PES polymer. Spectroscopy, microscopy and contact angle were some of the techniques used to characterize the ENMs. SEM images showed smooth and unbranched ENMs. The average diameter upon incorporation of the GOQDs was determined to be 2.45μm. XRD revealed that theGOQDs werestructurally close to graphite with an interlaying space of 0.36nm. The antimicrobial effect of the GOQDs-PES electrospun nanofibrous membranes was assessed against three bacterial strains (Escherichia coli (E. coli), Staphylococcus aureus (S. aureus) and Bacillus cereus (B. cereus)) using the disc diffusion method. The electrospun nanofibres containing10wt% of GOQDs showed the most active antimicrobial activity against all three bacterial strains tested. The zones of inhibition ranged from 9 to 40mm. The minimum inhibitory concentration (MIC) was determined to be 0.5mg/mL, 0.3mg/mL and 0.2mg/mL for E. coli, B. cereus and S. aureus, respectively. The results demonstrated that incorporating GOQDs in the PES nanofibre gives rise to new antimicrobial properties, and as a result, the GOQDs-PES nanofibrous membrane can be used in antimicrobial applications such as water treatment.

Electrospun Nanofibrous Membranes with Essential Oils for Wound Dressing Applications

To develop bioactive and interactive wound-dressing materials based on natural products, poly(vinyl alcohol) (PVA) nanofibrous membranes containing plant-derived essential oils were fabricated and their potential applications for wound dressing were examined. Since essential oils, particularly palmarosa oil and phytoncide oil, possess natural antimicrobial and anti-inflammatory properties and are ecofriendly, they were chosen as bioactive agents to be incorporated into the nanofiber matrix. Antimicrobial efficacy, air/moisture vapor transport, and water uptake properties of the composite membranes were assessed to find suitable processing conditions for effective wound care. Palmarosa oil or phytoncide oil was incorporated into the core of PVA nanofibers via emulsion electrospinning. The PVA-based composite nanofibrous membranes were heat-treated to increase their stability in aqueous environments. Qualitative and quantitative antimicrobial assessments showed that the membranes containing palmarosa oil possessed superior antimicrobial effects against Staphylococcus aureus and Candida albicans over the membranes containing phytoncide oil. Air/moisture vapor transport and water uptake properties were assessed for the PVA-based composite membranes having two levels of web area density to find suitable conditions for creating an optimal wound-healing environment. The composite nanofibrous membranes, which had a web area density of 3 g/m2, provided reasonable levels of gas and moisture vapor permeability for effective wound care and possessed water uptake ability to allow exudate absorption. These results demonstrate that the electrospun core/sheath structured PVA nanofibrous membranes containing palmarosa oil have high potential as bioactive wound-dressing materials.

Electrospun Nanofibrous Membranes: An Effective Arsenal for the Purification of Emulsified Oily Wastewater

AbstractOil spills and the release of oily sewage from domestic and industrial activities have not only imposed a huge threat to all living beings in the ecosystem but have also exacerbated water scarcity. To address such issues, the development of advanced materials and technologies for the purification of emulsified oily wastewater has garnered great concern and become a central topic. Electrospun nanofibrous membranes with intriguing advantages, including tunable wettability, diverse structures, good connectivity, and ease of scalable production, have generated significant interest and are showing great promise for treating emulsified oily wastewater. Here, a systematic overview of the rational design and controlled fabrication of nanofibrous membranes toward the separation of oil‐in‐water emulsions is given. Some design considerations about the fabrication of membranes for emulsion separation are presented as a starting point for the discussion. Electrospun nanofibrous membranes with desirable wettability and rational structure are then introduced and classified as polymeric, inorganic, and hybrid membranes in terms of raw material components. The different design concepts, fabrication strategies, and performance characteristics of each type are comprehensively discussed. Furthermore, significant properties are presented, which are required by membranes in practical applications. Finally, the challenges and future development trends in this field are highlighted.

Hybrid electrospun nanofibrous membranes: Influence of layer arrangement and composition ratio on tensile and transport properties

The present research aimed to investigate the influence of layer arrangement and composition ratio on tensile and transport properties in bi-constituent electrospun nanofibrous membranes composed of polyurethane nanofibers with a hydrophobic nature and poly(2-acrylamido-2-methylpropanesulfonic acid) with a hydrophilic nature. Different hybrid electrospun nanofibrous membranes were produced based on different layer arrangement and composition ratios. To evaluate the membrane performance, their tensile strength, wind, and waterproof performance were measured. By adding 50% poly(2-acrylamido-2-methylpropanesulfonic acid) to polyurethane, the pore size of the hybrid electrospun nanofibrous membranes decreased by 47.64%. As a result, compared with pristine polyurethane membranes, hybrid electrospun nanofibrous membranes showed a good (9.6 mm s−1) windproof performance. Adding poly(2-acrylamido-2-methylpropanesulfonic acid) nanofibers to the polyurethane resulted in a decrease in mechanical properties and waterproof performance. The results show that the volume fraction of the poly(2-acrylamido-2-methylpropanesulfonic acid) and the electrospinning scenarios have a great influence on the mechanical properties of the samples. The results also show that the mechanical properties of hybrid electrospun nanofibrous membranes can be predicted based on the geometrical properties of each component. Computational fluid dynamics were used to simulate air flow through a virtual medium and the results of simulation were compared with the experimental measurement and predicted permeability; then, the best models for predicting air permeability were determined. In addition, based on different types of use, duration of use, and relative humidity level, a bi-functional membrane can be obtained by regulating layer arrangement and composition ratios to suit various applications, for example, in medical disposable clothing, wound dressing, filtering industries, and protective clothing.

Hot-melt Adhesive Bonding of Polyurethane/Fluorinated Polyurethane/Alkylsilane-Functionalized Graphene Nanofibrous Fabrics with Enhanced Waterproofness, Breathability, and Mechanical Properties.

Waterproof-breathable (WB) materials with outstanding waterproofness, breathability, and mechanical performance are critical in diverse consumer applications. Electrospun nanofibrous membranes with thin fiber diameters, small pore sizes, and high porosity have attracted significant attention in the WB fabric field. Hot-press treatment technology can induce the formation of inter-fiber fusion structures and hence improve the waterproofness and mechanical performance. By combining electrospinning and hot-press treatment technology, polyurethane/fluorinated polyurethane/thermoplastic polyurethane/alkylsilane-functionalized graphene (PU/FPU/TPU/FG) nanofiber WB fabric was fabricated. Subsequently, the morphologies, porous structure, hydrostatic pressure, water vapor transmission rate (WVTR), and stress–strain behavior of the nanofiber WB fabric were systematically investigated. The introduction of the hydrophobic FG sheet structure and the formation of the inter-fiber fusion structure greatly improved not only the waterproofness but also the mechanical performance of the nanofiber WB fabric. The optimized PU/FPU/TPU-50/FG-1.5 WB fabric exhibited an excellent comprehensive performance: a high hydrostatic pressure of 80.4 kPa, a modest WVTR of 7.6 kg m−2 d−1, and a robust tensile stress of 127.59 MPa, which could be used to achieve various applications. This work not only highlights the preparation of materials, but also provides a high-performance nanofiber WB fabric with huge potential application prospects in various fields.

Magnesium-containing silk fibroin/polycaprolactone electrospun nanofibrous scaffolds for accelerating bone regeneration

Bone tissue engineering has become one of the most effective methods for treating bone defects. In this study, an electrospun tissue engineering membrane containing magnesium was successfully fabricated by incorporating magnesium oxide (MgO) nanoparticles into silk fibroin and polycaprolactone (SF/PCL)-blend scaffolds. The release kinetics of Mg2+ and the effects of magnesium on scaffold morphology, and cellular behavior were investigated. The obtained Mg-functionalized nanofibrous scaffolds displayed controlled release of Mg2+, satisfactory biocompatibility and osteogenic capability. The in vivo implantation of magnesium-containing electrospun nanofibrous membrane in a rat calvarial defect resulted in the significant enhancement of bone regeneration twelve weeks post-surgery. This work represents a valuable strategy for fabricating functional magnesium-containing electrospun scaffolds that show potential in craniofacial and orthopedic applications.

Low-temperature synthesis of novel polyvinylalcohol (PVA) nanofibrous membranes for catalytic dye degradation

Electrospun nanofibre membranes are employed to treat wastewater from dye pollution because of their outstanding properties. In this study, novel polyvinyl alcohol (PVA)-based hydrophilic electrospun nanofibre membranes were prepared using low-temperature synthesis (LTS) at 50 °C with a persulfate (PS) reagent and applied successfully to catalytic methylene blue (MB) dye degradation. The prepared nanofibre membranes were characterised with scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). The LTS–based PVA nanofibre membranes had small diameters, and exhibited better mechanical stability and enhanced hydrophilicity. The catalytic degradation percentage of MB increased in the presence of the LTS PVA membrane due to the generation of sulphate radicals and the crosslinking between PVA and PS. The degradation of MB by the LTS PVA membrane was also found to be satisfactory when MB was mixed with methyl orange (MO) in a binary system. The influences of operational parameters including solution pH, initial MB concentration, and catalyst dosage on the degradation performance of MB were evaluated. The role of inorganic ions such as NaCl and NaHCO3 on MB degradation was also investigated under optimised conditions. The LTS PVA nanofibre membrane exhibited excellent stability after repeated recycling experiments (90% after five cycles), and provided an economical, sustainable process with low carbon emissions 18,75% lower than the HTS process, for good environmental impact.

Colorimetric determination of dopamine using an electrospun nanofibrous membrane decorated with gold nanoparticles

This study reports the preparation of a flexible nanofibrous probe for the rapid colorimetric detection of dopamine. To this aim, gold nanoparticles (AuNPs) were immobilized on the surface of electrospun nanofibrous membrane to obtain a new hybrid material. This hybrid structure would benefit from the properties of both nanofibers and AuNP, being (a) the porosity and high surface area of nanofibers, and (b) the unique optical properties of AuNP. The electrospun poly(ethylene terephthalate) (PET) nanofibrous membrane was alkaline treated in NaOH aqueous solution, followed by immersion in the AuNP solution. The morphology of AuNP-PET membranes was characterized using a field emission scanning electron microscopy. The AuNP-PET probes showed quick, visible color change (from red to dark blue) in the presence of dopamine at the physiological pH values. The visual detection limit was 0.5 μM. The color difference based on the formula of the L*a*b* color space was used to quantify the concentration of dopamine. The color difference increased almost linearly in the 0.5–500 µM concentration range. The presence of electrostatically adsorbed AuNP on the surface of nanofibers, along with the flexibility of the nanofibrous membrane, was responsible for fast, sensitive, and on-site detection of dopamine.