Electrospun Poly Vinyl Alcohol Nanofibers Research Articles

Nicotine-Loaded Polyvinyl Alcohol Electrospun Nanofibers as Transdermal Patches for Smoking Cessation: Formulation and Characterization

Nicotine-Loaded Polyvinyl Alcohol Electrospun Nanofibers as Transdermal Patches for Smoking Cessation: Formulation and Characterization

Preparation and characterization of glutathione loaded polyvinyl alcohol electrospun nanofibers

Reduced glutathione, or L-glutathione, is a tripeptide protein that occurs naturally in almost all cells of the human body. It is an antioxidant and plays a significant role in neutralizing oxidative stress. Oxidative stress is responsible for promoting many diseases and abnormalities in the body. This antioxidant decreases with time, and resulting in a number of disorders. To overcome these issues, experts recommend taking glutathione supplements. This study was aimed to design glutathione-loaded polyvinyl alcohol nanofibers, considering the properties of nanofibers that could be used as glutathione supplements to improve the deficiency of glutathione in the human body. With the electrospinning technique, poly (vinyl alcohol) loaded glutathione nanofibers were designed. The prepared nanofibers were characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), X-ray diffraction (XRD), and Ultraviolet-Visible Spectroscopy (UV–Vis) techniques. The antioxidant activity of the nanofibers was also determined; the activity indicated the eradication of free radicals.

Polyvinyl alcohol electrospun nanofiber membrane based solid-phase extraction for monitoring administered aminoglycoside antibiotics in various animal-derived foods.

This work aims to develop a widely applicable method to monitor administered AGs in various animal-derived food samples to ensure food safety. A polyvinyl alcohol electrospun nanofiber membrane (PVA NFsM) was synthesized and employed as solid-phase extraction (SPE) sorbent, in combination with UPLC-MS/MS, for the simultaneous detection of ten AGs in nine types of animal-derived food samples. PVA NFsM exhibited excellent adsorption performance for the targets (with an adsorption rate of over 91.09%), good matrix purification ability (with a reduction of 7.65%-77.47% in matrix effect after SPE), and good recyclability (can be reused 8 times). The method displayed a linear range of 0.1-25000μg/kg and attained limits of detection for AGs were 0.03-15μg/kg. Spiked samples demonstrated a recovery of 91.72%-100.04% with a precision of<13.66%. The practicality of the developed method was verified by testing multiple actual samples.

Electrospun PVA Nanofibers Loaded with Antimicrobial Herbal Extracts for Healing the Infectious Wound

Background: Low-cost, soluble polyvinyl alcohol (PVA) polymers enhance the efficacy of herbal formulations with established antimicrobial properties. Objectives: This study investigates the healing process of Staphylococcus aureus (S. aureus)-infected wounds using PVA loaded with herbal extracts, including Arnebia euchroma, Allium sativum, and Echinacea purpurea. Methods: minimal bactericidal concentration (MBC) and minimal inhibitory concentration (MIC) assays, Disk Diffusion Method (DDM) tests, and Gas Chromatography-Mass Spectrometry (GC/MS) analyses were conducted on herbal extract samples. Twelve male Wistar rats were divided into G1: Negative control group (healthy mice), G2: Wound model + S. aureus (Positive control), G3: wound model + S. aureus + Povidone-iodine, and G4: Wound model + S. aureus + PVA/formulation. Hematoxylin-eosin and immunofluorescent staining were employed to assess wound healing. Results: The ethanolic herbal extract exhibited potent antibacterial activity against S. aureus, with MIC and MBC values in the 1.87 mg/mL range. The PVA/formulation displayed a zone of inhibition with a diameter of 7 mm against S. aureus. Histopathological investigations indicated that the infected wound treated with Nanofibers extract experienced a significant reduction in inflammation between days 7 and 14. Notably, the increased CD3 expression at this site was remarkable for the healing process. Conclusions: Consequently, this experimental study suggests combining PVA and herbal extracts enhances antibacterial properties and promotes CD3 expression and re-epithelialization effects.

Efficient adsorptive removal of aminoglycoside antibiotics from environmental water

Aminoglycoside antibiotics (AGs) in environmental water are emerging pollutants that must be removed to protect human health and the ecosystem. However, removing AGs from environmental water remains a technical challenge due to high polarity, stronger hydrophilicity and unique characteristics of polycation. Herein, a thermal-crosslinked polyvinyl alcohol electrospun nanofiber membrane (T-PVA NFsM) is synthesized and firstly leveraged as the adsorptive removal of AGs from environmental water. The thermal crosslinking strategy is demonstrated to enhance both the water resistance and hydrophilicity of T-PVA NFsM, thereby effectively interacting with AGs with high stability. Experimental characterizations and analog calculations indicate that T-PVA NFsM utilizes multiple adsorption mechanisms, including electrostatic and hydrogen bonding interactions with AGs. As a result, the material achieves 91.09%–100% adsorption efficiencies and a maximum adsorption capacity of 110.35 mg g−1 in less than 30 min. Furthermore, the adsorption kinetics follow the pseudo-second-order model. After eight consecutive adsorption-desorption cycles, T-PVA NFsM with a simplified recycling process maintains a sustainable adsorption capability. Compared with other forms of adsorption materials, T-PVA NFsM has significant advantages such as less consumption of adsorbent, high adsorption efficiency and fast removal speed. Therefore, T-PVA NFsM-based adsorptive removal holds promise for eliminating AGs from environmental water.

Response Surface Optimization of Electro-Spun Polyvinyl Alcohol Nano-Fiber Membrane Process Parameters and its Characterization

An empirical exploration into the effects of time duration, voltage supply, concentration and flow rate on the membrane average fiber diameter and surface pore size distribution were done using response surface methodology (RSM) based on central compact design (CCD). The average fiber diameter and average surface pore diameter of the membrane (i.e. 110 nm and 130 nm, respectively) were obtained at optimum input parameters of 45 min, 10 wt. %, 12 kV and 1.0 mL/h for time duration, concentration, voltage supply, and flow rate, respectively. The optimization study shows that the predicted versus actual values of both membrane fiber diameter and surface pore diameter are at R2 = 0.96. In addition, the effect of glutaraldehyde on membrane crosslinking was also assessed for further studies. The results from FESEM images of the fabricated PVA nanofiber membranes using the optimized parameters revealed that the membranes showed smooth morphological structures without formation of beads. The thermo gravimetric analysis (TGA) results displayed an improvement in thermal stability after membrane crosslinking. From this study we have observed that the membrane average fiber diameter and surface pore diameter can be controlled by varying the electro-spinning parameters and can be utilized for wastewater treatment application.

Optically transparent polyvinyl alcohol composite film obtained by self-reinforcing and self-toughening with electrospun polyvinyl alcohol nanofibers: A solution processing strategy

Optically transparent polyvinyl alcohol (PVA) films with high tensile strength and toughness are urgently needed in optical field. However, the combination of good optically transparency and excellent mechanical properties is still an obstacle for the PVA films. Herein, PVA composite film obtained by self-reinforcing and self-toughening with electrospun PVA nanofibers possessing various solubility via a solution strategy is proposed to tackle this challenge. The uniaxially aligned PVA nanofibers were electrospun by a narrow roller; thereafter, the PVA composite films were fabricated by solution impregnation technique and mould pressing. Owing to the strong interface binding, entangled molecular chains, and close refractive index between PVA nanofiber and PVA matrix, the as-prepared PVA-based composite film showed satisfactory light transmittance of above 85% in the 400–800 nm wavelength range with the tensile strength and elongation at break achieving 70 MPa and 160.1%. This work proposed a new solution-based strategy to efficiently fabricate PVA composite films for optical applications.

SERS determination and multivariate classification of antibiotics in chicken meat using gold nanoparticle-decorated electrospun PVA nanofibers.

The fabrication of SERS substrate by gold nanoparticle-decorated polyvinyl alcohol electrospun nanofibers which has been used to detect trace sensing of two widely used poultry antibiotics doxycycline hydrochloride and enrofloxacin is demonstrated. The performance of the backscattered Raman signals from the proposed SERS substrate has been initially evaluated with two standard Raman active compounds namely malachite green and rhodamine-6G. The limit of detection of the proposed substrate is estimated to be 7.32 nM. Following this, the usability of the proposed SERS substrate has been demonstrated through the detection of the aforementioned antibiotics in chicken meat samples. The presence of antibiotics in chicken meat sample has been validated with the standard analytical tool of liquid chromatography-mass spectrometry and the results were compared with the proposed sensing technique. Further, principal component analysis has been performed to classify the antibiotics that are present in the field-collected meat samples.

Nigella/honey/garlic/olive oil co-loaded PVA electrospun nanofibers for potential biomedical applications.

The current work focuses on the formation of nanofibrous mats without the use of toxic solvents and metallic nanoparticles utilizing polyvinyl alcohol (PVA) and a blend of nigella, honey, garlic, and olive oil. Using deionized water (DI) water as a solvent, nanofibrous mats composed of PVA/nigella/honey (PNH) and PVA/garlic/honey/olive oil (PGHO) were developed. Methanol extraction was utilized to extract the therapeutic components of nigella sativa. Antibacterial and moisture management tests (MMT) were employed to examine the antibacterial and absorbance characteristics of the PNH and PGHO nanofibrous. Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) tests were employed to analyze the morphological and chemical characteristics. PGHO showed thermal stability up to 245°C, and PNH withstands until 225°C. PNH and PGHO both exhibited antibacterial activity against Staphylococcus aureus (S. aureus), with inhibition zones of 36mm and 35mm, respectively. The synthesized materials exhibited excellent absorbance properties, thermal stability, cytotoxicity, and the production of thin nanofibers with an average diameter between 150 and 170nm. The samples were characterized using FTIR spectra, which confirmed the presence of all components in the developed samples. To date, extensive research on electrospinning for biomedical applications has been undertaken using a variety of hazardous solvents and metallic nanoparticles. Briefly, our objective is to develop nanofibrous materials from plant extracts through a process called "green electrospinning" to observe the synergistic effect of multiple biocomponents incorporated nanofibers avoiding toxic solvents and metallic compounds for potential biomedical applications.

Extended investigation of Ficus religiosa based PVA electrospun nanofiber for cosmeceutical application

The compositionalcharacteristics, antibacterial, and antioxidant activity of polyvinyl alcohol (PVA)containing Ficus religiosaleaf extract (FR) at 5 % and10 wt%fabricated through electrospinning technique were examined. The mechanicaland water vapour permeability of PVA was enhanced by adding a 5 % loading of leaves extract, i.e., 80 % and 30 %, respectively. The nanofibers' antioxidant and antibacterial activities were improved by adding 5 %and 10 % loaded FR leaves extract. The colour of the nanofiberswas also marginally altered by adding more FR extract. The inclusion of extractincreased the thermal stability of films by 20 %. Improvements in the interfacial contacts between the leaves extract andPVA were carried about by the functional groups and binding characteristics of the PVA's extractedsurface and macromolecular structures. Increases in FR extractcontent impact the PVA matrix's distribution mechanism. This study demonstrated the advantages of adding Ficus religiosa leaves extractto PVA nanofibersand the possibilities for using them as the active material for cosmeceutical applications like skin enhancement or skin healing.

Fabrication and Characterization of the Electrospun Polyvinyl Alcohol Nanofibers Incorporated with the Extracted Fruit Peel Pectin and Zinc Oxide Nanoparticles

Abstract Herein, pomegranate, orange, and cantaloupe peel pectins were extracted. Then, nanofibrous membranes of polyvinyl alcohol (PVA)/pectin with various ratios (70:30, 80:20, and 90:10) were fabricated by using a standard electrospinning procedure. In the next step, various concentrations of zinc oxide (ZnO) nanofiller were introduced into the PVA/pectin electrospun fibers. Finally, the effects of pectin and ZnO ratios on morphology and mechanical characteristics of the electrospun fibers were evaluated. Based on the scanning electron microscopy images, thinner fibers were formed by an increase of the pectin and ZnO proportions in the electrospun fibers. According to the obtained Fourier-transform infrared spectroscopy (FTIR), all extracted pectins were high methoxy. In addition, complexation between the PVA polymer chains, extracted pectins, and ZnO particles was confirmed by FTIR spectra. Moreover, increase of the pectin and ZnO ratios led to fabrication of fibers with superior mechanical strength and lower strain.

Chemically Cross-Linked Graphene Oxide as a Selective Layer on Electrospun Polyvinyl Alcohol Nanofiber Membrane for Nanofiltration Application.

Graphene oxide (GO) nanosheets were utilized as a selective layer on a highly porous polyvinyl alcohol (PVA) nanofiber support via a pressure-assisted self-assembly technique to synthesize composite nanofiltration membranes. The GO layer was rendered stable by cross-linking the nanosheets (GO-to-GO) and by linking them onto the support surface (GO-to-PVA) using glutaraldehyde (GA). The amounts of GO and GA deposited on the PVA substrate were varied to determine the optimum nanofiltration membrane both in terms of water flux and salt rejection performances. The successful GA cross-linking of GO interlayers and GO-PVA via acetalization was confirmed by FTIR and XPS analyses, which corroborated with other characterization results from contact angle and zeta potential measurements. Morphologies of the most effective membrane (CGOPVA-50) featured a defect-free GA cross-linked GO layer with a thickness of ~67 nm. The best solute rejections of the CGOPVA-50 membrane were 91.01% for Na2SO4 (20 mM), 98.12% for Eosin Y (10 mg/L), 76.92% for Methylene blue (10 mg/L), and 49.62% for NaCl (20 mM). These findings may provide one of the promising approaches in synthesizing mechanically stable GO-based thin-film composite membranes that are effective for solute separation via nanofiltration.

Fabrication and characterization of jujube extract-loaded electrospun polyvinyl alcohol nanofiber for strawberry preservation.

Recently, using of natural ingredients gains much attention in the field of food science and active packaging. In this study, first, jujube extract was investigated for its antimicrobial and antioxidant properties, and then, the effect of electrospun PVA/JE (jujube extract loaded into Poly vinyl alcohol) nanofiber as active packaging was evaluated to increase the shelf‐life of strawberry. PVA/ZE nanofiber film was prepared using electrospinning method, and their morphology was confirmed by scanning electron microscopy (SEM). Fruit preservation abilities of the nanofiber film were tested on strawberries. The strawberries were then kept at 4℃ for 15 days and characterized in terms of their properties (weight loss, TSS, firmness, and sensory analysis). Results indicated that flavonoid content of jujube extract ranged from 4.80 ± 0.01 to 13.54 ± 0.08 mg CEQ/100 g, and the DPPH free radical‐scavenging activity was from 210 ± 2.66 to 1498 ± 2.65 (GAE/g DW). The jujube extract also presented potent antibacterial activity against the investigated bacteria and fungi. The scanning electron microscopy (SEM) images of nanofibers had a linear morphology and bead‐free structure; however, PVA/JE (jujube extract encapsulated into PVA nanofiber) had strip and flat organization. Strawberries in control group showed signs of decay and a decrease in visual appearance on the 6th. However, fruits in PVA/JE group had acceptable overall appearance for marketing, as no obvious sign of decay was observed on 12th day of storage. Active packaging containing herbal extracts and essential oils preserves the organoleptic and physicochemical properties of the fruits.

Formononetin/methyl-β-cyclodextrin inclusion complex incorporated into electrospun polyvinyl-alcohol nanofibers: Enhanced water solubility and oral fast-dissolving property

Improving solubility and administration route of isoflavone formononetin (FMN) are critical factors to improve its bioavailability in the oral cavity. This study fabricated fast-dissolving nanofibers containing FMN/methyl-β-cyclodextrin (FMN/Me-β-CD) inclusion complex. The solubility of FMN could be increased by approximately 50 times at 20 mM aqueous Me-β-CD. Interactions and thermodynamic parameters of the host-guest inclusion complex were studied by a fluorescence quenching method. The structure and mechanisms of the complex were further studied by molecular docking and molecular dynamics. Finally, polyvinyl-alcohol (PVA) nanofibrous webs containing the FMN/Me-β-CD inclusion complex were fabricated by electrospinning. The dissolution test demonstrated that the FMN/Me-β-CD/PVA nanofibers can be dissolved in artificial saliva within approximately 2 s. This study shows the potential of Me-β-CD inclusion and electrospinning to improve solubility and administration route of isoflavones.

Fabrication and characterization of coblended methyl cellulose with polyvinyl alcohol electrospun nanofibers as a carrier for drug delivery system

Polymeric nanofibers have gained a great deal of attention in recent years. This study aims to produce and evaluate a methylcellulose (MC) and polyvinyl alcohol (PVA) based nanofibers mat using the electrospinning process. 25–2 fractional factorial screening design has been used to study the effect of critical formulation and process parameters, such as concentration of MC (%), the concentration of PVA (%), applied Voltage (kV), distance (cm), flow rate (ml/hr) on the critical quality attributes like fiber diameter, tensile strength, and morphology. The fiber morphology and fiber diameter of nanofibers were investigated by scanning electron microscopy (SEM).s The optimized nanofibers mat was further characterized by Fourier transform infrared (FTIR) spectroscopy, Differential scanning electrons (DSC), Thermal gravimetric analysis (TGA), X-ray diffraction (XRD), Atomic force microscopy (AFM). Parameters such as contact angle and rate of biodegradation were studied for an optimized batch. The SEM results showed the uniform morphology of optimized nanofibers without beads with fiber diameter in the range of 100–200 nm. FTIR analysis demonstrated good intermolecular interactions between the molecules of MC with PVA. DSC-TGA study showed good thermal properties of nanofibers. XRD study showed the crystalline nature of nanofibers. Maximum tensile strength up to 2.74 Mpa was obtained which is desired for drug delivery application. The exaggeration of the fiber diameter was measured by AFM and found good surface morphology. Furthermore, results of contact angle and biodegradation rate proved that prepared nanofibers would be considered as a suitable carrier for controlled drug delivery applications like wound healing.

Optimally controlled morphology and physico-mechanical properties of inclusion complex loaded electrospun polyvinyl alcohol based nanofibrous mats for therapeutic applications

Hydrophilic polyvinyl alcohol (PVA) based electrospun nanofibrous mats (ENMs) are recently being used for the designing and fabrication of active wound dressing materials. Thus, in this study an inclusion complex (IC) of curcumin (CUR) and β-cyclodextrin (β-CD) was optimally incorporated in electrospun PVA nanofibers, to obtain uniform bead-free nanofibers with minimum average diameter and variation using Taguchi’s design of experiments (DOE). The optimum level parameters were ascertained using Taguchi’s methodology, to obtain IC loaded PVA based bead-free ENMs, by varying IC (∼20, ∼40, and ∼60 wt.%) loading, applied voltage, solution concentration, and N, N-dimethylformamide (DMF) content in the electrospinning solution mixture. Validation experiments revealed a good agreement between the predicted and experimental values of fiber diameter, diameter-variation, and bead-numbers. Analysis of variance (ANOVA) showed a major influence of IC loading on the average fiber diameter and the number of bead defects, for IC-loaded PVA based ENMs. However, the DMF content of the solvent mixture significantly influenced the diameter variations of ENMs. The surface morphologies of ENMs were analyzed using Scanning Electron Microscopy (SEM) whereas the microstructural aspects were studied by Wide-Angle X-ray Diffraction (WAXD) and Fourier transform infrared (FT-IR) spectroscopy. The thermal properties were characterized by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) whereas the mechanical properties were measured by using uniaxial tensile testing and dynamic mechanical analysis (DMA). The variation in properties of IC loaded PVA based ENMs were correlated with neat PVA based ENMs fabricated using a similar set of optimized electrospinning process parameters. The study conceptually demonstrated the optimal designing of structurally-engineered hydrophilic IC loaded PVA based ENMs by using the Taguchi approach based on orthogonal DOE as potential drug release substrates.

Epidermal and fibroblast growth factors incorporated polyvinyl alcohol electrospun nanofibers as biological dressing scaffold

In this study, single, mix, multilayer Polyvinyl alcohol (PVA) electrospun nanofibers with epidermal growth factor (EGF) and fibroblast growth factor (FGF) were fabricated and characterized as a biological wound dressing scaffolds. The biological activities of the synthesized scaffolds have been verified by in vitro and in vivo studies. The chemical composition finding showed that the identified functional units within the produced nanofibers (O–H and N–H bonds) are attributed to both growth factors (GFs) in the PVA nanofiber membranes. Electrospun nanofibers' morphological features showed long protrusion and smooth morphology without beads and sprayed with an average range of 198–286 nm fiber diameter. The fiber diameters decrement and the improvement in wettability and surface roughness were recorded after GFs incorporated within the PVA Nanofibers, which indicated potential good adoption as biological dressing scaffolds due to the identified mechanical properties (Young’s modulus) in between 18 and 20 MPa. The MTT assay indicated that the growth factor release from the PVA nanofibers has stimulated cell proliferation and promoted cell viability. In the cell attachment study, the GFs incorporated PVA nanofibers stimulated cell proliferation and adhered better than the PVA control sample and presented no cytotoxic effect. The in vivo studies showed that compared to the control and single PVA-GFs nanofiber, the mix and multilayer scaffolds gave a much more wound reduction at day 7 with better wound repair at day 14–21, which indicated to enhancing tissue regeneration, thus, could be a projected as a suitable burn wound dressing scaffold.

The Removal of Reactive Red 141 From Wastewater: A Study of Dye Adsorption Capability of Water-Stable Electrospun Polyvinyl Alcohol Nanofibers

Abstract The dye production and its use in textile and related industries resulted in discharge of dye to wastewater. Adsorption for color removal is known as equilibrium separation process, and the resultant decolorization is influenced by physicochemical factors such as adsorbent surface area. The nanofiber membranes prepared by the electrospinning method have controllable nanofiber diameter and pore size distribution (PSD) with a high surface area to volume or mass ratio. In this study, polyvinyl alcohol (PVA) nanofibrous membranes were prepared by the electrospinning method at different collection times such as 3, 5 and 10 h and heat fixated at 130, 150 and 170°C for 10 min, and then, the adsorption capability of PVA nanofiber membranes for Reactive Red 141 from aqueous solution was investigated. In order to make PVA nanofibers stable to water, the nanofibrous membranes were chemically cross-linked by a polycarboxylic acid (1,2,3,4 butanetetracarboxylic acid (BTCA)). PVA nanofibrous membranes were characterized by scanning electron microscopy, thermogravimetric analysis, swelling tests and pore size analysis. The results indicated that BTCA crosslinking improved the thermal and water stability of the nanofibrous structure but has no significant effect on the pore sizes of the membranes. Adsorption of Reactive Red 141 was studied by the batch technique, and it was observed that PVA nanofibers removed approximately &gt;80% of the dye.

Immobilization of anthocyanin extract from red-cabbage into electrospun polyvinyl alcohol nanofibers for colorimetric selective detection of ferric ions

An effective nanofibrous metallochromic sensor mat was developed. Electrospun nanofibers were generated from a solution of polyvinyl alcohol (PVA) as a host polymer and anthocyanin extract from red-cabbage as an active detection sites. Using PVA as a supramolecular hosting matrix and anthocyanin phenolic dye (AC) as a spectroscopic probe, a novel, simple, rapid, portable and colorimetric sensor was developed for ferric ions (Fe3+) in aqueous environments. Binding these toxic ferric cations causes an appreciable color change from colorless to pink as proved by the CIE Lab color parameters. The visible color variation was found to change proportionally depending on increasing the concentration of ferric ions. The naked-eye recognition of Fe3+ was rationalized on the basis of Fe(III)-phenolic anthocyanin complex formation. High Performance Liquid Chromatography Mass Spectrometry (HPLC-MS) was applied to characterize the anthocyanin extract. The surface morphology and structural characterization of the generated nanofibers were explored by scanning electron microscopy (SEM) and energy-dispersive X-ray analyzer (EDS). The generated electrospun PVA-AC nanofibrous film displayed an average diameter of 150–250 nm. They were firstly cross-linked using the vapors of glutaraldehyde to turn them into water-insoluble nanofibers. Both selectivity and detection limit have been also studied. The anthocyanin-containing nanofibers display an excellent simplicity and reusability with a limit of detection in the range between 1 and 350 mg/L. The detection limit was monitored as low as 1 mg/L. PVA-AC showed excellent selectivity compared to other transition metal ions, including Cu2+, Mg2+, Hg2+, Co2+, Ba2+, Zn2+, Ni2+, Cr3+, Al3+, Ca2+, K+, Na+, Cd2+ and Mn2+. The best optimized conditions for the detection of Fe3+ was achieved in a pH range from 3.75 to 6.0. The proposed assay has the advantage of rapidity, simplicity, facile fabrication, low cost, environmental safety and easy to operate compared to other detection techniques.

A Facile Method for the Fabrication of Silver Nanoparticles Surface Decorated Polyvinyl Alcohol Electrospun Nanofibers and Controllable Antibacterial Activities.

Polyvinyl alcohol (PVA) electrospun nanofibers (NFs) are ideal carriers for loading silver nanoparticles (Ag NPs) serving as antibacterial materials. However, it is still a challenge to adjust the particles size, distribution, and loading density via a convenient and facile method in order to obtain tunable structure and antimicrobial activities. In this study, Ag NPs surface decorated PVA composite nanofibers (Ag/PVA CNFs) were fabricated by the solvothermal method in ethylene glycol, which plays the roles of both reductant and solvent. The morphology and structure of the as-fabricated Ag/PVA CNFs were characterized by scanning electron microscopy, transmission electron microscopy, selected area electron diffraction, X-ray diffraction, UV-visible spectroscopy, and Fourier transform infrared spectroscopy. Ag NPs had an average diameter of 30 nm, the narrowest size distribution and the highest loading density were successfully decorated on the surfaces of PVA NFs, at the AgNO3 concentration of 0.066 mol/L. The antibacterial properties were evaluated by the methods of absorption, turbidity, and growth curves. The as-fabricated Ag/PVA hybrid CNFs exhibit excellent antimicrobial activities with antibacterial rates over 98%, especially for the sample prepared with AgNO3 concentration of 0.066 mol/L. Meanwhile, the antibacterial effects are more significant in the Gram-positive bacteria of Staphylococcus aureus (S. aureus) than the Gram-negative bacteria of Escherichia coli (E. coli), since PVA is more susceptive to S. aureus. In summary, the most important contribution of this paper is the discovery that the particles size, distribution, and loading density of Ag NPs on PVA NFs can be easily controlled by adjusting AgNO3 concentrations, which has a significant impact on the antibacterial activities of Ag/PVA CNFs.