Electrospun Polystyrene Nanofibers Research Articles

Using 1,8-cineole plasma with both pulsed and continuous depositions to modify commercially available wound dressing materials.

The current clinical standards for infected chronic wounds are oral and topical antibiotics. These strategies are problematic because antibiotic resistance can occur with prolonged use. As an alternative to clinical methods, essential oils show promise in preventing bacterial growth. Specifically, 1,8-cineole-an active component in eucalyptus oil-exhibits antifungal, anti-inflammatory, and antibacterial properties. Applying 1,8-cineole directly onto a wound is challenging, however, due to its volatile nature. To combat this issue, plasma-enhanced chemical vapor deposition (PECVD) has been established as a method to deposit a stable 1,8-cineole-derived film on model surfaces (e.g., glass and electrospun polystyrene nanofibers). The current study represents an extension of previous work, where both pulsed and continuous 1,8-cineole plasmas were used to deposit a 1,8-cineole-derived film on two commercially available wound dressings. Three surface analyses were conducted to characterize the plasma-modified dressings. First, water contact angle goniometry data demonstrated a decrease in hydrofiber wettability after treatment. Through scanning electron spectroscopy, the surface morphology of both materials did not change upon treatment. When comparing pulsed and continuous treatments, deconvolution of high-resolution C1s x-ray photoelectron spectra showed no differences in functional group retention. Importantly, the chemical compositions of treated wound dressings were different compared to untreated materials. Overall, this work seeks to elucidate how different PECVD parameters affect the surface properties of wound dressings. Understanding these parameters represents a key step toward developing alternative chronic wound therapies.

Sampling and concentration of particulate matter bound polycyclic aromatic hydrocarbons (PAHs) basing on polystyrene nanofibers followed a determination by gas chromatography-mass spectrometry

Electrospun polystyrene (PS) nanofibers as an effective particulate filter and a sorbent in a packed-fiber solid phase extraction (PFSPE) were used to develop a novel method for the sampling and concentration of sixteen polycyclic aromatic hydrocarbons (PAHs) in the atmospheric particulate matter (PM). The PAHs were quantified by gas-chromatography-mass spectrometry (GC–MS). The main factors (the shape of PFSPE devices, the leaching solvents, and the elution methods) affecting the adsorption and desorption of PAHs on PS nanofibers were evaluated in detail. Under the optimized conditions (sampling of particulate matter bound PAHs basing on PS nanofibers filter following the release of them with ultrsound for 20 min in ethanol, the concentration of PAHs by adsorption of them on PS nanofibers again in a disk PFSPE-column, eluting of PAHs in ethanol at 75 ○C for 10 min), PS nanofibers displayed excellent properties in the sampling of PM bound PAHs and in the concentration of PAHs in the leaching solution with the recoveries ranging from 79.2 to 104.5%. The linear calibration curves were in the range of 0.17 to 64.9 ng m−3, and relative standard deviations (RSDs) were 3.8–11.6% for intra-day, 4.3–10.2% for inter-day. The method was fast, sensitive, cost-effective, with less harmful reagents, and has great potential for analyzing PAHs in atmospheric particulate matter.

An all-fibrous triboelectric nanogenerator with enhanced outputs depended on the polystyrene charge storage layer

Electrospun fibers based-triboelectric nanogenerators (EF-TENGs) are considered to have a positive application prospect on wearable energy harvesters. However，the poor comfortable breathability and low output performance under weak force as the common problems which are associated with the EF-TENGs are the principal issue that impede the practical applications. Here, an improved EF-TENG with breathable-antibacterial electrode and electrostatic induction enhancement layer is proposed by introducing silver nanowires (AgNWs) as electrodes and electrospun polystyrene (PS) nanofibers as charge storage layer, respectively. Based on this, a high-performance all-fibrous materials-based triboelectric nanogenerator (AF-TENG) is successfully fabricated and investigated. A high output voltage 200 V and current density 70 mA/m2 was achieved with the work area of 90 mm2 and AF-TENG was demonstrated could charge the economical capacitor with 1 μF to 2 V at a short time of 40 s under a continuous driven force and frequency at 1 Hz. Simultaneously, AF-TENG acts as a real-time force detective sensor integrated with normal fabrics also show excellent performance with a high signal-to-noise ratio. Based on these characteristics of AF-TENG verified above, this work is thought to inspire an effective ponder to the evolution of wearable energy harvester.

Multifunctional Photosensitizing and Biotinylated Polystyrene Nanofiber Membranes/Composites for Binding of Biologically Active Compounds

A three-step postprocessing functionalization of pristine electrospun polystyrene nanofiber membranes was used for the preparation of nanostructured biotinylated materials with an externally bonded porphyrin photosensitizer. Subsequently, the material was able to strongly bind biologically active streptavidin derivatives while keeping its photosensitizing and antibacterial properties due to the generation of singlet oxygen under the exclusive control of visible light. The resulting multifunctional materials functionalized by a streptavidin-horseradish peroxidase conjugate as a model bioactive compound preserved its enzymatic activity even in the presence of a porphyrin photosensitizer with some quenching effect on the activity of the photosensitizer. Prolonged kinetics of both singlet oxygen luminescence and singlet oxygen-sensitized delayed fluorescence (SODF) were found after irradiation by visible light. The above results reflected less effective quenching of the porphyrin photosensitizer triplet state by ground state oxygen and indicated hindered oxygen transport (diffusion) due to surface functionalization. We found that SODF could be used as a valuable tool for optimizing photosensitizing efficiency as well as a tool for confirming surface functionalization. Full photosensitizing and enzyme activity could be achieved by a space separation of photosensitizers and enzyme/biomolecules in the nanofiber composites consisting of two layers. The upper layer contained a photosensitizer that generated antibacterial singlet oxygen upon irradiation by light, and the bottom layer retained enzymatic activity for biochemical reactions.

Interfacial Biocatalytic Performance of Nanofiber-Supported β-Galactosidase for Production of Galacto-Oligosaccharides

Molecular distribution, structural conformation and catalytic activity at the interface between enzyme and its immobilising support are vital in the enzymatic reactions for producing bioproducts. In this study, a nanobiocatalyst assembly, β-galactosidase immobilized on chemically modified electrospun polystyrene nanofibers (PSNF), was synthesized for converting lactose into galacto-oligosaccharides (GOS). Characterization results using scanning electron microscopy (SEM) and fluorescence analysis of fluorescein isothiocyanat (FITC) labelled β-galactosidase revealed homogenous enzyme immobilization, thin layer structural conformation and biochemical functionalities of the nanobiocatalyst assembly. The β-galactosidase/PSNF assembly displayed enhanced enzyme catalytic performance at a residence time of around 1 min in a disc-stacked column reactor. A GOS yield of 41% and a lactose conversion of 88% was achieved at the initial lactose concentration of 300 g/L at this residence time. This system provided a controllable contact time of products and substrates on the nanofiber surface and could be used for products which are sensitive to the duration of nanobiocatalysis.

Adsorption of Ce3+ and Nd3+ by diglycolic acid functionalised electrospun polystyrene nanofiber from aqueous solution

Highly selective and stable ligands with fast kinetics for rare earth element extraction are not well developed. Durable attachment of ligands to the support would make regeneration possible. Polystyrene nanofiber supports (PS-nF) were prepared using the electrospinning method. Thereafter, PS-nf were chemically modified with diglycolic anhydride (DGA) to produce novel electrospun polystyrene diglycolic acid nanofiber (PS-DGAnf) adsorbents. The immobilisation reaction proceeded via an electrophilic aromatic substitution of the ligand onto the PS nanofiber. The maximum gravimetric loading of DGA on PS nanofiber was 0.827 g g−1. The unmodified and modified nanofibers were characterised by ATR-FTIR, HR-SEM, BET and TGA. After optimising pH, time and concentration, the equilibrium adsorption and binding kinetics of cerium (Ce3+) and neodymium (Nd3+) ions on the nanofibers surface were examined at pH 6. The adsorption capacity of PS-DGAnf for Ce3+ and Nd3+ at pH 6.0 was 152.5 mg g−1 (1.09 mmol/g) and 146.2 mg g−1 (1.01 mmol/g) respectively. Selectivity of Ce3+ over Ni2+, Co2+ and Sr3+ was also studied at pH 6. The amount of Ce3+ adsorbed even in the presence of interfering ions was 100.3 mg g−1, which was only a little lower than 119.4 mg g−1 obtained in a single ion solution. The rapid adsorption kinetics of Ce3+ and Nd3+ ions were achieved within 15 mins. The desorption and regeneration was carried out with 1 M nitric acid and the developed PS-DGAnf adsorbent could be reused for 4 cycles without any substantial loss to its adsorption abilities.

Electrospun polystyrene nanofiber adsorbent for solid phase extraction of phenol as its quinoid derivative from aqueous solutions

In the present study, polystyrene nanofibers (PS NFs) were synthesized by electrospinning method and used as adsorbents in solid phase extraction of phenol from aqueous solutions. Phenol was reacted with 4-aminoantipyrine (4-AAP) reagent in presence of potassium hexacyanoferrate (III). The coloured product was extracted by solid phase extraction using electrospun synthesized polystyrene nanofibers and determined by UV-Vis spectrophotometer. At certain conditions of electrospinning process, the variables affecting the solid phase extraction efficiency were studied and optimized. Under the optimized conditions, (sorbent mass: 0.025 g PS NF, sample flow rate: 2.5 mL min−1, eluent: acetone: NaOH 0.1 M (1:1 v/v)), the linear dynamic range (LDR) and limit of detection (LOD as 3 Sb/m) for extraction of phenol from 50 mL of aqueous solutions were determined as 15-2500 µg L-1 and 10 µg L-1, respectively. The precision (as RSD %) of the extraction method using the proposed adsorbent was lower than 7.6%. Finally, the applicability of the proposed method for the extraction of phenol from industrial aqueous samples was examined and satisfactory results were obtained.

Rationally designed mesoporous In2O3 nanofibers functionalized Pt catalysts for high-performance acetone gas sensors

Here, we demonstrate a facile design and simple fabrication of acetone gas sensors based on one-dimensional (1D) porous platinum (Pt)-doped In2O3 nanofiber structure. Be first to try to immerse electrospun polystyrene (PS) nanofibers (NFs) into a precursor solution followed by an annealing process, the as-prepared composite NFs can readily turn into Pt-In2O3 porous NFs. The obtained Pt-In2O3 porous NFs exhibit the mesoporous size of 4–6 nm and high specific surface area of 212.3 m2 g-1. We observed that the spillover effect of Pt nanoparticles and the large-surface-area of the porous structure can effectively enhance catalytic sensing response to acetone with a lower limit of 10 part-per-billion (ppb) at a low working temperature of 180 °C. More importantly, the proposed NFs-based sensor shows rapid response and recovery time (6/9 s), higher selectivity toward acetone against other interfering gases, reversibility and time stability (50 days) compared to its counterparts. In addition, the proposed sensor shows a fast response and recovery time, maintaining 70% of the initial response even in 85% relative humidity (RH) environment. These results demonstrate the potential feasibility that the Pt-In2O3 porous NFs act as a promising sensing platform for monitoring acetone at ppb levels in human breath.

Investigating the enzymatic CO2 reduction to formate with electrochemical NADH regeneration in batch and semi-continuous operations

The enzymatic production of formate from CO2 with the immobilized NADH-dependent formate dehydrogenase (FDH) on the activated electrospun polystyrene nanofibers (EPSNF) was investigated to develop a sustainable process for CO2 reduction. Direct electrochemical regeneration on a Cu foam electrode was employed to supply the reaction with the reduced cofactor (NADH). The formate production was studied in two modes of batch and semi-continuous operations with the cofactor recycle. Results indicated that the regenerated cofactor concentrations in both systems were nearly identical (0.5 mM) which ensured the desirable activity of the immobilized enzyme. This showed that the electrochemical regeneration system was effective even in the semi-continuous operation. Although the cumulative formate concentration in the batch operation was higher, the total amounts of the produced formate were higher for the semi-continuous mode for more than 42% which was justified by the fact that the lower formate concentration in the semi-continuous mode would be favorable to the progress of the enzymatic CO2 to formate conversion. Finally, it was concluded that the proposed semi-continuous process in this work could be considered as a promising process for the enzymatic CO2 conversion.

Multifunctional polystyrene nanofiber membrane with bounded polyethyleneimine and NO photodonor: dark- and light-induced antibacterial effect and enhanced CO2 adsorption

Herein, we report the preparation, characterization and antibacterial evaluation of electrospun polystyrene nanofiber membrane with covalently bonded polyethyleneimine and NO photodonor. The nanofiber membranes were prepared by electrospinning, followed by two-step functionalization of the nanofiber surface by chlorosulfonic acid and then by polyethyleneimine (PEI) with or without NO photodonor. Nanofiber membranes with PEI and NO photodonor are characterized by a high hydrophilicity, photogeneration of NO radicals and CO2 retention. Due to the photogeneration of highly antibacterial NO radicals, the nanofibers exhibited an efficient antibacterial effect toward Gram-negative Escherichia coli when activated by visible light. The functionalization of the nanofiber membranes by PEI was responsible for the antibacterial character of the surface of the nanofiber membranes even in the dark, showing low bacteria adherence and the retention of CO2. The combination of the properties of the membranes including also protecting against pathogens passing through the nanofiber membrane suggests that these nanomaterials have a promising broad range of applications in medicine.

Enzymatic CO2 reduction to formate by formate dehydrogenase from Candida boidinii coupling with direct electrochemical regeneration of NADH

Enzymatic conversion of CO2 to formate was carried out in the cathodic cell of a two-chamber electrochemical apparatus where NAD+ was reduced on the surface of a Copper foam electrode. Formate dehydrogenase (FDH) was used as the biocatalyst in both free form and immobilized on the modified electrospun polystyrene nanofibers (EPSNF). The fabricated EPSNF were modified by a multistage procedure including acid treatment, silanization followed by activation with glutaraldehyde. The effects of regenerated NADH concentration and time of enzymatic reaction on the formate production in the both systems were studied. The results indicated that the EPSNF immobilized FDH had a desirable activity, long-term storage stability (41% after 20 days) and reusability after eight cycles of successive reactions (53% of the initial activity). Moreover, it was revealed that the increase of cofactor concentration at the early times of reaction was favorable to the formate production. However, an inhibitory effect was observed at higher concentrations of NADH, and the optimum values of 0.45 mM and 0.51 mM were obtained for the maximum enzyme activity by the free and immobilized enzymes respectively. The produced formate at the optimum cofactor concentration after 300 min was 0.61 mM and 0.31 mM for the free and immobilized enzyme systems. Finally, it can be concluded that the presented process is a promising approach to the enzymatic conversion of CO2.

Electrospun 3,5-dithienylvinyleneBODIPY embedded polystyrene nanofibers for the photocatalytic degradation of azo dyes in industrial wastewaters

The potential utility of electrospun polystyrene (PS) nanofibers embedded with 2,6-diiodo-8-phenyl-1,7-dimethyl-3,5-di-2-thienylvinyleneBODIPY for the photocatalytic degradation of azo dyes is investigated. A comparison of the singlet oxygen quantum yield of the [Formula: see text]-extended BODIPY dye in solution and in the PS nanofibers demonstrates that its photosensitizer properties are retained when it is embedded in the solid phase. The photocatalytic degradation properties of the PS nanofibers for Methyl Orange and Orange G were determined by using a Thorlabs 625 nm light emitting diode. The rate of photodegradation increases with the Orange G and Methyl Orange concentration and follows pseudo-first order kinetics at pH 6.7.

Ultrafine copper decorated polypyrrole nanotube electrode for nitrite detection

In this report, a nitrite electrochemical sensor was developed by electrochemical deposition of copper nanoparticles on the polypyrrole nanotubes (PPy-Cu). The PPy nanotubes were synthesized via pyrrole polymerization on electrospun polystyrene nanofibers (PS) with the diameter of 150 nm, followed by PS removal. The prepared nanotubes were characterized using Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). Ultrafine Cu nanoparticles with the size of 4.2 ± 1.2 nm were uniformly deposited on PPy tubes by electrolysis. The existence of zero valence Cu particles was demonstrated by transmission electron microscopy (TEM) and X-ray photo spectroscopy (XPS). The electrochemical behaviors of the PPy and PPy-Cu electrodes were investigated by cyclic voltammetry (CV). PPy enhances the deposition of Cu dramatically and facilitates the uniform distribution of the copper nanoparticles. The obtained PPy-Cu exhibits an excellent catalytic activity to the reduction of nitrite. The catalytic performance of the resultant PPy-Cu electrodes was optimized by varying the PPy morphology and Cu deposition amount. Using hydrodynamic current-time curves, the linear relationship was obtained, under the optimized conditions, in the range of 0.1 μM to 1 mM with a limit of detection of 0.03 μM (S/N > 3). The sensor presents good reproducibility and stability for nitrite determination.

Multifactorial modeling and optimization of solution and electrospinning parameters to generate superfine polystyrene nanofibers

AbstractThis study was conducted to provide a quantitative understanding of the influence of the different solution and electrospinning variables on the morphology and the mean diameter of electrospun polystyrene nanofibers. In this regard, the effect of different solvents and ionic additives on the electrical conductivity, viscosity, and surface tension of the electrospinning solutions and thereby the morphology of nanofibers were examined. The results indicated that the morphology of the fibers is extremely dependent on the solvent's properties, especially volatility and electrical conductivity, and the ionic characteristics of additives. Finally, to estimate the optimal electrospinning conditions for production of nanofibers with minimum possible diameter, modeling of the process was undertaken using the response surface methodology. Experimentally, nanofibers with the finest diameter of 169 ± 21 nm were obtained under the optimized conditions, and these could be considered promising candidates for a wide practical range of applications ranging from biosensors to filtration.

Effective SERS detection using a flexible wiping substrate based on electrospun polystyrene nanofibers

In this paper we demonstrate a flexible SERS substrate that offers effective in situ sampling by wiping directly from the surface of luggage, fruits or any surface of interest.

BODIPY Dye Embedded Electrospun Polystyrene Nanofibers for the Photocatalytic Degradation of Orange G in Industrial Wastewaters

BODIPY Dye Embedded Electrospun Polystyrene Nanofibers for the Photocatalytic Degradation of Orange G in Industrial Wastewaters

Antibacterial, Antiviral, and Oxygen-Sensing Nanoparticles Prepared from Electrospun Materials.

A simple nanoprecipitation method was used for preparation of stable photoactive polystyrene nanoparticles (NPs, diameter 30 ± 10 nm) from sulfonated electrospun polystyrene nanofiber membranes with encapsulated 5,10,15,20-tetraphenylporphyrin (TPP) or platinum octaethylporphyrin (Pt-OEP). The NPs prepared with TPP have strong antibacterial and antiviral properties and can be applied to the photooxidation of external substrates based on photogenerated singlet oxygen. In contrast to nanofiber membranes, which have limited photooxidation ability near the surface, NPs are able to travel toward target species/structures. NPs with Pt-OEP were used for oxygen sensing in aqueous media, and they presented strong linear responses to a broad range of oxygen concentrations. The nanofiber membranes can be applied not only as a source of NPs but also as an effective filter for their removal from solution.

Electrospun polystyrene nanofibers as a novel adsorbent to transfer an organic phase from an aqueous phase.

The aim of this work is to develop a simple phase-transfer method for dispersive liquid-liquid microextraction. For this purpose, a polystyrene nanofiber was prepared by a facile electrospinning strategy and used for the first time as an adsorbent to transfer the organic phase in dispersive liquid-liquid microextraction procedure. The fiber was characterized and its chemical stability and excellent hydrophobicity enable it to selectively adsorb the organic solvent in an aqueous sample. High porosity and specific surface area provide a large adsorption capacity. Under the optimal conditions, the developed dispersive liquid-liquid microextraction with high-performance liquid chromatography method was successfully applied to the analysis of aldehydes in environmental water samples. The merits of this approach are that it is easy-to-operate, low-cost, time-saving, and has satisfactory sensitivity. It provides an alternative way for fast and convenient phase transfer of the hydrophobic organic solvent from the aqueous phase.

Electrospun Polystyrene Nanofiber as an Adsorbent for Solid-Phase Extraction of Disulfine Blue from Aqueous Samples

In this research, polystyrene nanofibers were synthesized by electrospinning method and used as adsorbent in solid-phase extraction of Disulfine blue from aqueous solutions. Some important parameters affecting extraction efficiency including sample flow rate through the adsorbent, ionic strength, pH of the sample solution, weight of adsorbent, volume, and type of eluent were evaluated and optimized. Under the optimized conditions, the calibration graph was linear in the range of 6.4–1000 \({{{\rm \mu{g}} {\rm L^{-1}}}}\) with correlation coefficient \({({r^{2}})}\) of 0.9962. The limit of detection and enhancement factor of proposed method, for extraction from 50 mL sample solution, were obtained as 2 \({{{\rm \mu{g}} {\rm L^{-1}}}}\) and 9.5, respectively. Finally, the proposed method was successfully applied for extraction and measurement of Disulfine blue from real samples, and satisfactory results were obtained.

Polystyrene Nanofiber Materials for Visible-Light-Driven Dual Antibacterial Action via Simultaneous Photogeneration of NO and O2((1)Δg).

This contribution reports on the preparation, characterization, and biological evaluation of electrospun polystyrene nanofiber materials engineered with a covalently grafted NO photodonor and ionically entangled tetracationic porphyrin and phthalocyanine photosensitizers. These photofunctional materials exhibit an effective and simultaneous photogeneration of two antibacterial species such as nitric oxide (NO) and singlet oxygen, O2((1)Δg) under illumination with visible light, as demonstrated by their direct detection using amperometric and time-resolved spectroscopic techniques. Dual-mode photoantibacterial action is demonstrated by antibacterial tests carried out on Escherichia coli.