Polyvinylpyrrolidone Nanofibers Research Articles

Cholesterol included self-assembled electrospun proliposomes as a feasible approach for drug delivery

Liposomes are the most well established systems for drug delivery due to their biocompatibility, extended circulation time and availability of surface modification. Besides, there are limitations mainly related with their inadequate stability. Electrospinning is a versatile method which incorporates many drugs into polymeric nanofibers. Self-assembly liposomes obtained from nanofibers could be an advantageous approach that can overcome the stability problems of liposomes. In this study, proliposome nanofibers of soy phosphatidylcholine(PC) and PC/Cholesterol(Chol) were developed in dry state using polyvinylpyrrolidone(PVP), by a single step method, electrospinning. Hydrocortisone(HC) was used as a hydrophobic model drug. All formulations were successfully electrospun according to SEM images. DSC, FT-IR and XRD studies showed that the drug was encapsulated and transformed into an amorphous form. The hydration of PC/Chol containing nanofibers provides to form liposomes around 150 nm with −30mV zeta potential and 0.23 polydispersity index. Self-assembled liposomes obtained by hydration of nanofibers and PDI values were found to be very low without extrusion or sonication step. No vesicular structure was observed for PVP nanofibers without PC. The release studies showed the addition of Chol to nanofiber structure, enhanced HC release within 48 h. Additionally, three-months stability data showed that Chol improves in vitro stability of liposomes.

In vitro and in vivo evaluation of multi-target-directed Rivastigmine/Memantine/Gingko biloba-loaded nanofibers against Alzheimer's disease

The highly complex pathophysiology of Alzheimer's disease (AD) and the low bioavailability of the currently used drugs make it necessary to offer versatile treatment options. In this study, polyvinyl alcohol (PVA)/polyvinylpyrrolidone (PVP) nanofibers (NFs) were loaded with rivastigmine (RIV), memantine (MM), and Gingko biloba (GB) extract, and their anti-Alzheimer's effects were investigated in vitro by cell culture and in vivo by animal experiments. The characterization studies, including FTIR, XRD, and DSC analysis, showed that the fibers exhibited a good compatibility. The rapid disintegration (in 5.2 s) and complete dissolution (in 120 s) of RIV/MM/GB-loaded NF indicated their suitability for sublingual application. Cell viability analysis revealed that RIV/MM/GB-loaded NFs can be considered as safe and promising candidates. RIV/MM/GB-loaded NFs tremendously improved the learning and memory impairment seen in the AD model created by the injection of intracerebroventricular-streptozotocin into rats. Moreover, RIV/MM/GB-loaded NF stimulated stem cells to improve neuronal differentiation properties and significantly decreased the level of β-amyloid, tau, APP, TNF-α, AChE, and GSK-3β in the brain. The histopathological and immunostaining assays demonstrated that RIV/MM/GB-loaded NF reduced β-amyloid formation and tau hyperphosphorylation in the hippocampus and cerebral cortex. Thus, a novel and promising treatment strategy could be developed that has several advantages, such as ease of sublingual administration, reduced frequency of administration associated with lower drug amounts, and finally reduced toxicity and cost.

Polyvinylpyrrolidone Nanofibers Incorporating Mesoporous Bioactive Glass for Bone Tissue Engineering.

Composite biomaterials that combine osteoconductive and osteoinductive properties are a promising approach for bone tissue engineering (BTE) since they stimulate osteogenesis while mimicking extracellular matrix (ECM) morphology. In this context, the aim of the present research was to produce polyvinylpyrrolidone (PVP) nanofibers containing mesoporous bioactive glass (MBG) 80S15 nanoparticles. These composite materials were produced by the electrospinning technique. Design of experiments (DOE) was used to estimate the optimal electrospinning parameters to reduce average fiber diameter. The polymeric matrices were thermally crosslinked under different conditions, and the fibers' morphology was studied using scanning electron microscopy (SEM). Evaluation of the mechanical properties of nanofibrous mats revealed a dependence on thermal crosslinking parameters and on the presence of MBG 80S15 particles inside the polymeric fibers. Degradation tests indicated that the presence of MBG led to a faster degradation of nanofibrous mats and to a higher swelling capacity. The assessment of in vitro bioactivity in simulated body fluid (SBF) was performed using MBG pellets and PVP/MBG (1:1) composites to assess if the bioactive properties of MBG 80S15 were kept when it was incorporated into PVP nanofibers. FTIR and XRD analysis along with SEM-EDS results indicated that a hydroxy-carbonate apatite (HCA) layer formed on the surface of MBG pellets and nanofibrous webs after soaking in SBF over different time periods. In general, the materials revealed no cytotoxic effects on the Saos-2 cell line. The overall results for the materials produced show the potential of the composites to be used in BTE.

Improving Solubility and Permeability of Hesperidin through Electrospun Orange-Peel-Extract-Loaded Nanofibers.

Orange peel, which is a rich source of polyphenolic compounds, including hesperidin, is produced as waste in production. Therefore, optimization of the extraction of hesperidin was performed to obtain its highest content. The influence of process parameters such as the kind of extraction mixture, its temperature and the number of repetitions of the cycles on hesperidin content, the total content of phenolic compounds and antioxidant (DPPH scavenging assay) as well as anti-inflammation activities (inhibition of hyaluronidase activity) was checked. Methanol and temperature were key parameters determining the efficiency of extraction in terms of the possibility of extracting compounds with the highest biological activity. The optimal parameters of the orange peel extraction process were 70% of methanol in the extraction mixture, a temperature of 70 °C and 4 cycles per 20 min. The second part of the work focuses on developing electrospinning technology to synthesize nanofibers of polyvinylpyrrolidone (PVP) and hydroxypropyl-β-cyclodextrin (HPβCD) loaded with hesperidin-rich orange peel extract. This is a response to the circumvention of restrictions in the use of hesperidin due to its poor bioavailability resulting from low solubility and permeability. Dissolution studies showed improved hesperidin solubility (over eight-fold), while the PAMPA-GIT assay confirmed significantly better transmucosal penetration (over nine-fold). A DPPH scavenging assay of antioxidant activity as well as inhibition of hyaluronidase to express anti-inflammation activity was established for hesperidin in prepared electrospun nanofibers, especially those based on HPβCD and PVP. Thus, hesperidin-rich orange peel nanofibers may have potential buccal applications to induce improved systemic effects with pro-health biological activity.

Effect of molecular weight and content of polyvinylpyrrolidone on cell proliferation, loading capacity and properties of electrospun green tea essential oil-incorporated polyamide-6/polyvinylpyrrolidone nanofibers

Electrospun nanofibers demonstrate a novel category of materials that display great potential in numerous biomedical applications including tissue engineering, drug delivery, regenerative medicine, and wound healing. Here, composite nanofibrous scaffolds of polyamide-6 (PA-6), polyvinylpyrrolidone (PVP), and tea tree oil (TTO) was fabricated by electrospinning method and the effect of various molecular weight of PVP on properties of produced fiber scaffolds was studied. The investigations showed that the increase in the molecular weight of PVP, as well as the decrease in its content provides the thinner fibers (220.90 ± 59.0 nm) with higher porosity (∼90%), high water vapor transmission rate (WVTR) (3945. g/m2.24 h), and low surface wettability (∼85°). The morphological investigation accomplished with scanning electron microscope (SEM) showed the uniform bead-free electrospun fibers scaffold. The structural characteristics of the produced scaffolds were investigated with Fourier Transform Infrared Spectroscopy (FTIR). The results of the mechanical test of the produced fibers confirmed their ability to protect the wound area against external forces during the healing process. Antibacterial and antioxidant tests of samples containing TTO showed excellent and strong activities. Besides, the in vitro cytotoxicity, and cell adhesion was evaluated, that the obtained results illustrated that the electrospun fibers were biocompatible and supported cell adhesion. Based on the findings, this new electrospun matrix is expected to be effective as a potential wound dressing for skin regeneration.

A Highly Sensitive Flexible Pressure Sensor Based on Inter-Comb Structured Graphene Electrodes

Susceptible and flexible pressure sensors have broad application prospects and market demands in bionic skin, human–machine interface, and intelligent wearable electronic devices. However, optimizing the sensor’s sensitivity through a simple, low-cost process is still a considerable challenge. In this work, the sensitivity of a capacitive pressure sensor was effectively improved by optimizing the geometry of the laser-scribed graphene (LSG) electrodes. The pressure sensor, based on the inter-comb structured LSG electrodes and polyvinyl pyrrolidone nanofiber membrane (PVP NM) dielectric layer, has a high sensitivity (4.352 kPa <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-\text{1}}$</tex-math> </inline-formula> at 0–2 kPa), a fast response/recovery time (40/37 ms), an ultralow detection limit ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim$</tex-math> </inline-formula> 12 Pa), and excellent mechanical stability (6000 cycles). The sensor developed in this research can be used in health monitoring such as carotid artery pulsation and respiratory disease. In addition, the 6 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times$</tex-math> </inline-formula> 6 sensor array can precisely characterize the regional pressure distribution. This study demonstrates the significant potential of the inter-comb structured LSG electrodes in highly sensitive flexible pressure sensors.

An investigation of the influence of nanofibers morphology on the performance of QCM-based ethanol vapor sensor utilizing polyvinylpyrrolidone nanofibers active layer

Quartz crystal microbalances (QCMs) coated by polyvinylpyrrolidone (PVP) nanofibers with controlled morphology have been made for ethanol vapor detection. We used electrospinning to deposit PVP nanofibers of different morphologies (spherical-beaded, spindle-beaded, and pure nanofiber) on a QCM surface to study the effect on sensor performance. BET characterization revealed that the spherical-beaded nanofiber had the highest BET-specific surface area than the other morphologies, which improves the QCM sensor sensitivity, limit of quantification (LOQ), limit of detection (LOD), and sensor response. QCM coated with spherical-beaded nanofiber showed improved sensitivity of 2.632 Hz/ppm, lower LOD and LOQ of 0.018 ppm and 0.061 ppm, and better response compared to those coated with spindle-beaded and pure nanofiber. Based on adsorption isotherm models, Freundlich adsorption isotherm was found to be the most suitable for describing ethanol vapor adsorption on the sensor. The high sensitivity of the sensor to ethanol vapor was attributed to hydrogen bonding interactions between the sensor and the ethanol molecules. This study shows that the QCM-based sensor performance can be improved by modifying the morphology of nanofibrous coating layer.

Super disintegrating oromucosal nanofiber patch of zolmitriptan for rapid delivery and efficient brain targeting

Oromucosal administration of zolmitriptan using electrospun nanofiber can potentially result in blood plasma concentrations analogous to intravenous kinetics and targeting the brain due to anatomical features of the delivery site. Herein, we report the optimization of zolmitriptan and polyvinylpyrrolidone nanofibers using a Quality by Design approach. Fourier transform infrared spectroscopy, and Thermogravimetric analysis ruled out any physical and/or chemical interaction between the drug and excipient. Diffraction studies revealed a sharp decrease in the crystalline index of pure zolmitriptan from 85.75% to 8.35%. Likely, calorimetry studies show a sharp decline in the enthalpy of fusion from 126.4 J/g before electrospinning to 67.24 J/g post electrospinning, demonstrating amorphization of the drug. The disintegration of nanofiber occurs within less than a second, and about 82% of the medicament was released in 60 s in an in vitro test, compared to 67% from the Zomig Rapimelt® tablet. Rapid drug flux of 22.07 and 22.62 μg/cm2/h occurred when nanofiber patches were applied to buccal and soft palate mucosa in an ex vivo permeability test. Biocompatibility studies established that the nanofiber patches were neither toxic nor irritating to the oral epithelium. Groups of rabbits received the zolmitriptan solution intravenously and orally, or optimized nanofibers were applied to the buccal and soft palate mucosa. Pharmacokinetic analysis in blood plasma indicated similar kinetics of oromucosal patches and intravenous administration. More importantly, concentrations achieved in the hindbrain after administration of the patch over the soft palatal mucosa produce significantly higher concentrations than buccal or IV administration (>2-folds). The drug targeting these brain regions likely resulted from rapid dissolution, enhanced permeation, amorphization, and specialized drug transport via a trigeminal nose base-pons-medullary axis.

Fabrication and characterization of anti-rosacea 3D nanofibrous customized sheet masks as a novel scaffold for repurposed use of spironolactone with pre-clinical studies

The repurposed oral use of spironolactone (SP) as an anti-rosacea drug faces many challenges that hinder its efficacy and compliance. In this study, a topically applied nanofibers (NFs) scaffold was evaluated as a promising nanocarrier that enhances SP activity and avoids the friction routine that exaggerates rosacea patients’ inflamed, sensitive skin. SP-loaded poly-vinylpyrrolidone (40% PVP) nanofibers (SP-PVP NFs) were electrospun. Scanning electron microscopy showed that SP-PVP NFs have a smooth homogenous surface with a diameter of about 426.60 nm. Wettability, solid state, and mechanical properties of NFs were evaluated. Encapsulation efficiency and drug loading were 96.34% ± 1.20 and 11.89% ± 0.15, respectively. The in vitro release study showed a higher amount of SP released over pure SP with a controlled release pattern. Ex vivo results showed that the permeated amount of SP from SP-PVP NFs sheets was 4.1 times greater than that of pure SP gel. A higher percentage of SP was retained in different skin layers. Moreover, the in vivo anti-rosacea efficacy of SP-PVP NFs using croton oil challenge showed a significant reduction in erythema score compared to the pure SP. The stability and safety of NFs mats were proved, indicating that SP-PVP NFs are promising carriers of SP.

Influence of Electrospinning Setup Parameters on Properties of Polymer-Perovskite Nanofibers.

Optimizing the properties of electrospun polymer-perovskite nanofibers is considered essential for improving the performance of flexible optoelectronic devices. Here, the influence of electrospinning setup parameters (i.e., electrical voltage, collector type (planar or rotary), rotation speed, as well as process time) on the properties (i.e., external structure, perovskite crystallinity, optical properties, thermal properties, the shrinkage ratio, mechanical properties, and long-term stability) of electrospun polyvinylpyrrolidone nanofibers modified with cesium lead iodide nanocrystals has been studied. The results have shown that the structure of nanofibers is related to the electrical voltage, collector rotation speed, and process duration. Perovskite crystallinity and light absorption have improved by increasing the electrical voltage or/and the process time. The polymer's glass transition temperature is affected by the embedded perovskite and the collector's rotation speed. The shrinkage ratio and mechanical properties of nanofibers have been controlled by the rotation speed and the electrical voltage. The shrinkage is caused by the stress created in the nanofibers during the electrospinning process. The best mechanical properties can be noticed with the rotary collector at a rotational speed of 500--750 rpm. Nanofibers have shown good long-term stability and high thermal stability. The long-term stability is inversely proportional to the value of the electrical voltage.

Mechanically robust conjugated microporous polymer membranes prepared using polyvinylpyrrolidone (PVP) electrospun nanofibers as a template for efficient PM capture

Air pollution has become a challenging environmental problem worldwide due to rapid industrial development and excessive emissions of vehicle exhaust. Herein, we report a preparation of conjugated microporous polymer membranes (CMPM) with a hierarchical porous structure by electrospun polyvinylpyrrolidone (PVP) nanofibers as a template for effective removal of PM from airborne and vehicle exhaust. CMP membranes have hierarchical holes, where the macropores are from electrospun nanofiber membranes and the mesopores are from polymer synthesis. Taking advantage of its inherent physicochemical and thermal stability and hierarchical hole characteristics, the CMPM-based filter can work continuously for up to 36 h and still maintains a high removal efficiency (>99.56%), and also has a high filtration efficiency in the treatment of vehicle exhausts, with 95.18% for PM0.3, 98% for PM0.5 and >99% for PM2.5-10.0. The superior mechanical properties of CMPM allow the filter to be cleaned and reused. After three cycles, the filtration effectiveness of CMPM is still 94.83% for respirable particulate matter. Under high humidity (RH ≥ 95%) conditions, the CMPM-based filter showed higher than 95.37% filtration of PM0.3-10, and the oil adsorption rate could be maintained at 284% at high speed, proving the great potential of CMPM to clean air in complex situations.

Electrospinning of PVP Nanofibers and Optimization with Taguchi Experimental Design

The aim of this study is the determination of optimum process parameters which will provide the finest and the most uniform electrospun Polyvinylpyrrolidone (PVP) based nanofibers with Taguchi experimental design. For the designed experimental setup, parameters (solvent type, polymer concentration, voltage, distance between the electrodes, solution feed rate and humidity) were used which effect the electospinning process significantly. For this purpose, the appropriate orthogonal array was selected to determine the factors and levels at Taguchi experimental design application. The experimental design aimed which provides to be reduced the number of experiments and minimised the effect of uncontrollable factors with less experiments to obtain target value by using Taguchi orthogonal arrays. In the experimental studies of paper, firstly PVP polymer solutions such as conductivity, surface tension and viscosity were determined with various PVP concentrations (10, 12, 14 wt %) and solvents (ethanol, dimethylformamide, dimethylacetamide, chloroform, acetic acid and distilled water). Scanning Electron Microscope (SEM) images of electrospun PVP based nanofibrous surfaces were obtained, average fiber diameter and fiber diameter coefficient values were calculated by ImageJ image analyses software and fiber diameter distribution histogram curves were obtained by SPSS program. Experimental results were analyzed and commented by Taguchi method in MINITAB program with variance analysis. According to the results; solvent type has the highest effect on the electrospinning of PVP nanofibers. In this study, it is predicted to save in terms of time and cost with decreasing the number of experiments by Taguchi experiment design.

Real-Time Monitoring of Breath Biomarkers with A Magnetoelastic Contactless Gas Sensor: A Proof of Concept.

In the quest for effective gas sensors for breath analysis, magnetoelastic resonance-based gas sensors (MEGSs) are remarkable candidates. Thanks to their intrinsic contactless operation, they can be used as non-invasive and portable devices. However, traditional monitoring techniques are bound to slow detection, which hinders their application to fast bio-related reactions. Here we present a method for real-time monitoring of the resonance frequency, with a proof of concept for real-time monitoring of gaseous biomarkers based on resonance frequency. This method was validated with a MEGS based on a Metglass 2826 MB microribbon with a polyvinylpyrrolidone (PVP) nanofiber electrospun functionalization. The device provided a low-noise (RMS = 1.7 Hz), fast (<2 min), and highly reproducible response to humidity (Δf = 46–182 Hz for 17–95% RH), ammonia (Δf = 112 Hz for 40 ppm), and acetone (Δf = 44 Hz for 40 ppm). These analytes are highly important in biomedical applications, particularly ammonia and acetone, which are biomarkers related to diseases such as diabetes. Furthermore, the capability of distinguishing between breath and regular air was demonstrated with real breath measurements. The sensor also exhibited strong resistance to benzene, a common gaseous interferent in breath analysis.

The Use of Recycled PET for the Synthesis of New Mechanically Improved PVP Composite Nanofibers

Polyethylene terephthalate (PET) waste has become a major challenge for the conservation of the environment due to difficult degradation. For this reason, it is important to develop new recycling strategies for reusing this waste. In this work, the electrospinning technique was used to synthesize composite nanofibers of polyvinylpyrrolidone (PVP), recycling PET (RPET) that was obtained from the chemical recycling of postconsumer PET with glycolysis and styrene (ST) as a crosslinking agent. The polymer solutions were analyzed by viscosity and frequency sweeping, while the composite nanofibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis/differential scanning calorimetry (TGA/DSC), and nanoindentation to compare their properties. The PVP nanofibers presented an average diameter of 257 nm; the RPET/PVP and RPET/PVP/ST composite nanofibers had average diameters of 361 nm and 394 nm, respectively; and the modulus of elasticity and hardness of the RPET/PVP/ST composite nanofibers were 29 and 20 times larger, respectively, than those of the PVP nanofibers. With the synthesis of these composite nanofibers, a new approach to PET recycling is presented.

On an oxadiazole-pyridine derived diimine ligand and its Re complex: Synthesis, characterization and photophysical features

Recent development of optoelectronic functional films, photovoltaic devices, photocatalysts and display devices has attracted widespread attention on the design and synthesis of emitters and dyes with optoelectronic functions. Among these proposed emitters and dyes, polypyridine Re(I) carbonyl complexes are unique ones due to their simple molecular structure, which makes their chemical modification easy to perform. These Re(I) complexes could be explored as singlet oxygen (1O2) photosensitizer, which broadens their application. In this work, an electron-accepting diimine ligand with -CF3 group was incorporated into a Re(I) complex (denoted as Re-LCF3). This Re(I) complex was characterized by single crystal analysis, electronic structure analysis, photophysical property analysis, so that its phosphorescent nature was confirmed. Then Re-LCF3 was dispersed into nanofibers of polyvinylpyrrolidone by means of electro-spinning method, hoping to improve 1O2-producing performance of the resulting composite nanofibers (denoted as Re-LCF3@PVP). A full comparison between Re-LCF3 in solid state, in solution, in polymer fibers was performed, including their absorption, emission, quantum yield, lifetime and 1O2-producing performance. It was found that the photophysical performance of Re-LCF3@PVP was better than that of pure Re-LCF3 in solid state, showing emission blue shift, improved photostability, longer lifetime and better emission quantum yield. The 1O2-producing performance of Re-LCF3@PVP was better than that of pure Re-LCF3 in solid state.

Chlorogenic acid-loaded sandwich-structured nanofibrous film developed by solution blow spinning: Characterization, release behavior and antimicrobial activity

In this work, solution blow spinning (SBS) was used to rapidly develop a sandwich-structured nanofibrous film with an outer layer of polyurethane (PU) nanofibers and an inner layer of polyvinylpyrrolidone (PVP) nanofibers with chlorogenic acid (CGA) loading. Scanning electronic microscopy images showed that there were clear boundaries between the inner and outer layers. The hydrogen bonds that formed between the two layers enhanced the thermal stability. Compared to the CGA-loaded film, the sandwich structure increased the elongation at break and tensile strength from 3.01 ± 0.97% to 201.34 ± 9.63% and 0.0120 ± 0.0002 MPa to 0.1569 ± 0.0117 MPa, respectively, and the PU layer endowed the sandwich-structured film with hydrophobic surfaces. Furthermore, the sandwich structure shifted the burst release of the CGA-loaded film to a long-term sustained release within 144 h. In addition, the sandwich-structured film retained the antioxidant and antimicrobial activities of CGA. These results indicated that the sandwich-structured nanofibrous film developed by SBS possesses potential applications in food packaging.

Distinctive Sandwich-Type Composite Film and Deuterogenic Three-Dimensional Triwall Tubes Affording Concurrent Aeolotropic Conduction, Magnetism, and Up-/Down-Conversion Luminescence.

Compared to single functional materials, multifunctional materials with electrical conduction, magnetism, and luminescence are more attractive and promising, so it has become an important subject. A distinctive sandwich-type composite film (STCF) with dual-color up- and down-conversion luminescence, magnetism, and aeolotropic conduction is prepared by layer-by-layer electrospinning technology. Macroscopically, STCF is assembled by three tightly bonded layers, including a [polypyrrole (PPy)/poly(methyl methacrylate) (PMMA)]//[NaYF4:Yb3+, Er3+/PMMA] Janus nanobelt array layer as the first layer, a CoFe2O4/polyacrylonitrile (PAN) nanofiber nonarray layer as the second layer, and a Na2GeF6:Mn4+/polyvinylpyrrolidone (PVP) nanofiber nonarray layer as the third layer. This unique macropartition effectually confines conductive aeolotropy, magnetism, and luminescence in different layers. Microscopically, a Janus nanobelt is used as a construction unit to restrict the luminescent and conductive materials to their microregions, thus achieving highly conductive aeolotropy and green luminescence. The high integration of the micro-subarea and macro-subarea in the STCF can efficaciously avoid the mutual disadvantageous effects among different materials to obtain splendid polyfunctional performance. The conductive anisotropy and magnetism of the STCF can be adjusted by changing the contents of PPy and CoFe2O4. When the PPy content reaches 70%, the conductance ratio in the conductive direction to insulative direction is 108. The 2D STCF can be crimped by four different methods, and the 3D TWTs have the same excellent polyfunctional performances as 2D STCF. This unique design idea and construction technology can be applied to the preparation of other multifunctional materials to avoid harmful interference among various functions.

High‐Power Triboelectric Nanogenerator Based on Enriched Polyvinylpyrrolidone Nanofibers for Energy Harvesting

Triboelectric nanogenerators (TENGs) are a new, low‐cost, and easy‐to‐manufacture technology for converting mechanical energy into electrical energy. TENGs have great potential to be used in electronic devices, but their energy efficiency is low for use in commercial products today. The most important way to increase the energy efficiency of TENGs is to develop tribo‐positive and tribo‐negative materials with a large surface area and high dielectric coefficients. Herein, cetrimonium bromide (CTAB) and dodecyl trimethyl ammonium bromide (DTAB) organic molecule‐doped polyvinylpyrrolidone (PVP) nanofibers are tested as a positive dielectric layer against the negative dielectric layer made of polyacrylonitrile (PAN) nanofiber. The results reveal that CTAB and DTAB additives of 1, 2.5, and 5 wt% increase the tribo‐potential of PVP, while the additives of 7.5 and 10 wt% decrease the tribo‐potential of PVP. According to the electrical measurements, the maximum open‐circuit voltages are obtained as 500 and 515 V, whereas the maximum powers were obtained as 25.02 and 26.52 mW for the TENGs made of 5 wt% CTAB‐ and DTAB‐doped PVP nanofibers, respectively. The proposed cationic surfactant‐doped nanofibers can be employed as a positive dielectric layer to increase the energy efficiency and power density of TENGs.

A wearable and high-performance capacitive pressure sensor based on a biocompatible PVP nanofiber membrane via electrospinning and UV treatment

We report the fabrication, superior performance and applications of a flexible capacitive pressure sensor based on a biocompatible polyvinyl pyrrolidone nanofiber membrane, prepared by electrospinning and ultra-violet photochemical after treatment.

Effect of Allium cepa loaded polyacrylonitrile and polyvinyl pyrrolidone nanofibers on Candida albicans growth and the expression of CDR1 and CDR2 genes.

Background and Purpose: This study aimed to assess the effect of Allium cepa ethanolic extract (ACE) loaded polyacrylonitrile (PAN) and polyvinyl pyrrolidone (PVP) nanofibers on Candida albicans (C. albicans) CDR1 and CDR2 genes expression.Materials and Methods: The minimum inhibitory concentrations (MICs) of ACE against C. albicans ATCC 10231 and clinical fluconazole (FLC)-resistant C. albicans PFCC 93-902 were determined using the Clinical and Laboratory Standards Institute (CLSI) protocol (M27-Ed4) at a concentration range of 45.3-5800 µg/ml. The nanofibers containing ACE (60 wt%) were fabricated using the electrospinning technique. The expression of the CDR1 and CDR2 genes was studied in the fungus exposed to ACE-loaded nanofibers and 0.5×MIC concentration of FLC using the real-time polymerase chain reaction.Results: MIC50 and MIC90 of ACE against FLC-resistant C. albicans were 725 and 1450 μg/mL, respectively. The expression of CDR1 (4.5-fold) and CDR2 (6.3-fold) were down-regulated after the exposure of FLC-resistant C. albicans to ACE-loaded nanofibers (P<0.05). Furthermore, the expression of CDR1 (2.8-fold) and CDR2 (3.2-fold) were up-regulated in FLC-treated C. albicans (P<0.05).Conclusion: The results revealed that nanofibers containing ACE interact with drug-resistant genes expressed in C. albicans. Further studies are recommended to investigate the mode of action and other biological activities of ACE-loaded nanofibers against C. albicans and other pathogenic fungi.