Structure Of Nanofibers Research Articles

Harnessing nanostructures and fiber architecture: A synergistic leap in shape memory polymer composites

This research investigates the synergistic effects of carbon fiber orientation and nanostructure reinforcement across 21 configurations of shape memory polymer composites. It examines uni-directional (UD), bi-directional Twill (BDT), and bi-directional Plain (BDP) fiber architectures, along with varying concentrations of MWCNT and GnP at 0.4%, 0.6%, and 0.8%. The fabrication process involves initially preparing nanostructure-modified epoxy nanocomposites through ultrasonication followed by hand layup techniques to fabricate three-phase shape memory polymer composites. Optimal tensile performance is observed in GnP-modified UD composites at a 0.6 wt% concentration, achieving a tensile strength of 728.32 MPa and a modulus of 71.29 GPa. Furthermore, enhancements in thermomechanical and shape memory properties are noted in GnP-modified BDT composites and are further improved in GnP-modified BDP composite configurations. GnP-modified composites outperform MWCNT ones due to GnP’s sheet structure aligning parallel to the load and its larger surface area, which facilitate enhanced interaction with the matrix. These improvements, supported by FESEM analysis, highlight enhanced interfacial bonding and result in high shape recovery ratios, with all configurations exceeding 90%, despite polymer modification.

Novel versatile 5-aminoisophthalic acid modified chitosan nanofiber pads for adsorption toward Congo red, methyl orange, crystal violet, and methylene blue

To structure novel nanofiber pads for organic dye removal from dye-polluted water, we previously prepared CSP nanofiber pads by chitosan (CS) and polyethylene oxide (PEO) via electrospinning, followed by preparation of CSRP nanofiber pads through partial PEO removal from CSP, and the subsequent fabrication of CS-A nanofiber pads via grafting 5-aminoisophthalic acid (5-AIPA) to CSRP. FTIR, XRD, and elemental analyses confirmed the successful synthesis of CS-A nanofiber pads (crosslinking and crystalline degrees of 36.64 % and 4.57 %). CS-A nanofiber pads had porous nanofiber structures (diameter and pore size of 153.46 and 3.82 nm), high specific surface area (102.06 m2/g), great thermal stability (total mass loss of 50.2 %), excellent hydrophilicity (water contact angle of 12.0°), superior swelling performance (2331 %), good pH stability (pH of 3.0–11.0), and 6.8 of pHpzc, evidenced by SEM, Brunauer-Emmett-Teller (BET), thermogravimetric (TG), differential thermogravimetric (DTG), wettability, swelling, and solid addition tests. Optimum adsorption parameters (e.g., pH, dosage, and initial concentration) were selected by batches of tests on adsorption toward four organic dyes. CS-A’s surfaces were heterogeneous, and the adsorption belonged to spontaneous endothermic chemical adsorption, confirmed by kinetic and isothermal models and thermodynamic results. CS-A nanofiber pads were of great reusability and easy to be separated. Adsorption mechanisms involved electrostatic attractions, hydrogen bondings, π-stacking interactions, and pore fillings. Dynamic adsorption toward Congo red showed the Thomas model well fitted the breakthrough curves (R2 > 0.9971), showing the maximum adsorption capacity of 949.15 mg/g. Totally, CS-A nanofiber pads were effective adsorbents suitable for organic dye-containing wastewater purification.

Asymmetric Janus Nanofibrous Agar-Based Wound Dressing Infused with Enhanced Antioxidant and Antibacterial Properties.

In the present study, we have developed an agar-based asymmetric Janus nanofibrous wound dressing comprising a support and an electrospun layer with antibacterial and antioxidant properties, respectively, to facilitate healing effectively. The support layer containing agar and silver nitrate was fabricated by using solvent casting for sustained release, combating the dose-dependent cytotoxicity of silver nanoparticles, where nanoparticles were synthesized using a one-pot reduction method. The electrospun layer, fabricated with a mixture of agar and polycaprolactone infused with gallic acid, was electrospun over the support layer to impart antioxidant properties. Characterizations using UV-vis spectroscopy, transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy validated the synthesis of nanoparticles in 10-20 nm diameter and the asymmetric Janus dressing. The developed Janus nanofibrous structure exhibited 98% porosity, excellent fluid-handling properties, a moisture permeability of 1200 g/m2/day, and a water absorption of ∼250%. Moreover, the time-kill assay confirmed potent bacteriostatic effect against Gram-positive and Gram-negative bacteria, and sustained release of silver nanoparticles followed the Korsmeyer-Peppas model. With over 90% free radical scavenging efficacy, 37% degradation in 7 days, and less than 2% hemolysis, the dressings demonstrated exceptional antioxidant, biodegradable, and hemocompatible properties. The biocompatibility assessment further confirmed its cytocompatible efficacy, with more than 79% wound closure in the wound scratch assay. Most importantly, in vivo studies demonstrated the efficacy of the developed Janus dressing, promoting over 97% healing within 12 days of injury with higher epithelial formation. Overall, the in vitro and in vivo assessment of the developed Janus dressing confirmed its potential to function as a versatile and effective material for wound care applications.

Synthesis and characterization of novel electrospun nanofibers based on taro starch: influence of solvent and isolation agent on morphology and diameter

AbstractThe utilization of natural polymers in producing electrospun nanofibers has received significant attention due to their biocompatibility, sustainability and diverse range of applications. This research focuses on synthesizing electrospun nanofibers derived from taro starch isolated from tubers. The investigation utilized SEM to examine the structure and size of the electrospun nanofibers. Formic acid and dimethyl sulfoxide solvents were tested to determine the most efficient solvent system for synthesizing taro starch nanofibers. The results demonstrated that the taro starch nanofibers can be effectively synthesized when using formic acid as the primary solvent. The study also investigated the impact of altering the volumetric ratio of formic acid to water on nanofiber morphology and size, finding that a lower formic acid fraction produced smooth fibers while a higher fraction resulted in fused fibers. The electrospinnability was further evaluated by comparing the effects of different isolation agents—distilled water and sodium metabisulfite—during the isolation process. The isolation agent significantly affected the fiber diameter, with notable differences observed in the smoothness of taro starch nanofibers at starch solution concentrations of 13, 15 and 17 wt%. Overall, the results of the study showed that the formation of taro starch fibers was influenced by the type of solvent, the volume fraction of the solvent to water, and the starch isolation agent. Successful fabrication of nanofibers from taro starch and its optimization parameters can contribute to the development of environmentally friendly nanofiber materials and offer a variety of applications in biomedicine, food and environmental engineering, such as tissue engineering, wound dressing, drug delivery, functional food delivery and food packaging. © 2024 Society of Chemical Industry.

Engineering supramolecular peptide nanofibers for in vivo platelet-hitchhiking beyond ligand-receptor recognition.

Ex vivo or in vivo cell-hitchhiking has emerged as a potential means for efficient drug delivery and various disease therapies. However, many challenges remain, such as the complicated engineering process and dependence on ligand-receptor interaction. Here, we present a simple in vivo platelet-hitchhiking strategy based on self-assembling peptides without ligand modification. The engineered peptide nanofibers can hitchhike ultrafast (<5 s) and efficiently on both resting and activated platelets in a receptor-independent and species-independent manner. Mechanistic studies showed that unique secondary structure of nanofibers, which lead to surface exposure of hydrophobic and hydrogen bond-forming groups, might primarily contribute to the selective and efficient platelet-hitchhiking behavior. After intravenous injection, these peptide nanofibers hitchhiked in situ on circulating platelets and achieved almost 20-fold lung accumulation. Our study provides not only a different paradigm of in vivo platelet-hitchhiking beyond ligand-receptor recognition but also a potential strategy for lung-targeted drug delivery and pulmonary disease therapy.

Tuning the Electronic And Transport Properties of CaMoO4 Nanofibers with High-Spin Ni for Efficient and Stable Supercapacitors.

Calcium molybdate (CaMoO4) has recently garnered considerable attention for supercapacitors due to its stable crystal structure and cost-effective preparation. However, CaMoO4 prepared by traditional processes still suffered from insufficient electrochemical active sites and poor electrical conductivity so far, thus leading to the performance of CaMoO4-based supercapacitors being inferior to the state-of-the-art ones. CaMoO4 nanofibers with a high specific surface area exhibit great potential for supercapacitors due to their ability to offer increased charge storage. Herein, mesoporous CaMoO4 nanofibers anchored with Ni nanoparticles were fabricated via electrospinning combined with subsequent thermal treatment. Density functional theory calculation and UV-vis spectrophotometer results show that high-spin state Ni nanoparticles can tune the electronic structure of CaMoO4 nanofibers, decreasing the band gap by about 0.67 eV. Electron paramagnetic resonance (EPR) studies imply that Ni doping influences the electronic structure by reducing the oxygen vacancy concentration and introducing hyperfine structures associated with Ni spins. These can result in higher power and energy density in supercapacitors. As a result, a specific capacitance of 1253.7 F·g-1 at a current density of 0.5 A·g-1 and an 86% retention rate after 2000 cycles at a higher current density of 5 A·g-1 have been achieved for Ni0.25Ca0.75MoO4-based supercapacitor. Furthermore, an asymmetric supercapacitor (ASC) device with the optimized CaMoO4/Ni//AC structure has been demonstrated with the energy density of 49.43 Wh·kg-1 and power density of 2700 W·kg-1, thus enabling lightening a red light-emitting diode. The current strategy might pave the way for CaMoO4 for practical applications for high-power supercapacitors.

Synthesis of bifunctional α-Bi 2 O 3 nanostructured fibres for UV light and gas sensing applications

Synthesis of bifunctional α-Bi ₂ O ₃ nanostructured fibres for UV light and gas sensing applications

3D Cryo-Electron Microscopy Reveals the Structure of a 3-Fluorenylmethyloxycarbonyl Zipper Motif Ensuring the Self-Assembly of Tripeptide Nanofibers.

Short peptide-based supramolecular hydrogels appeared as highly interesting materials for applications in many fields. The optimization of their properties relies mainly on the design of a suitable hydrogelator through an empirical trial-and-error strategy based on the synthesis of various types of peptides. This approach is in part due to the lack of prior structural knowledge of the molecular architecture of the various families of nanofibers. The 3D structure of the nanofibers determines their ability to interact with entities present in their surrounding environment. Thus, it is important to resolve the internal structural organization of the material. Herein, using Fmoc-FFY tripeptide as a model amphiphilic hydrogelator and cryo-EM reconstruction approach, we succeeded to obtain a 3.8 Å resolution 3D structure of a self-assembled nanofiber with a diameter of approximately 4.1 nm and with apparently "infinite" length. The elucidation of the spatial organization of such nano-objects addresses fundamental questions about the way short amphiphilic N-Fmoc peptides lacking secondary structure can self-assemble and ensure the cohesion of such a lengthy nanostructure. This nanofiber is organized into a triple-stranded helix with an asymmetric unit composed of two Fmoc-FFY peptides per strand. The three identical amphiphilic strands are maintained together by strong lateral interactions coming from a 3-Fmoc zipper motif. This hydrophobic core of the nanofiber is surrounded by 12 phenyl groups from phenylalanine residues, nonplanar with the six Fmoc groups. Polar tyrosine residues at the C-term position constitute the hydrophilic shell and are exposed all around the external part of the assembly. This fiber has a highly hydrophobic central core with an internal diameter of only 2.4 Å. Molecular dynamics simulations highlight van der Waals and hydrogen bonds between peptides placed on top of each other. We demonstrate that the self-assembly of Fmoc-FFY, whether induced by annealing or by the action of a phosphatase on the phosphorylated precursor Fmoc-FFpY, results in two nanostructures with minor differences that we are unable to distinguish.

Application of electrospinning and 3D-printing based bilayer composite scaffold in the skull base reconstruction during transnasal surgery

Skull base defects are a common complication after transsphenoidal endoscopic surgery, and their commonly used autologous tissue repair has limited clinical outcomes. Tissue-engineered scaffolds prepared by advanced techniques of electrostatic spinning and three-dimensional (3D) printing was an effective way to solve this problem. In this study, soft tissue scaffolds consisting of centripetal nanofiber mats and 3D-printed hard tissue scaffolds consisting of porous structures were prepared, respectively. And the two layers were combined to obtain bilayer composite scaffolds. The physicochemical characterization proved that the nanofiber mat prepared by polylactide-polycaprolactone (PLCL) electrospinning had a uniform centripetal nanofiber structure, and the loaded bFGF growth factor could achieve a slow release for 14 days and exert its bioactivity to promote the proliferation of fibroblasts. The porous scaffolds prepared with polycaprolactone (PCL), and hydroxyapatite (HA) 3D printing have a 300 μm macroporous structure with good biocompatibility. In vivo experiments results demonstrated that the bilayer composite scaffold could promote soft tissue repair of the skull base membrane through the centripetal nanofiber structure and slow-release of bFGF factor. It also played the role of promoting the regeneration of the skull base bone tissue. In addition, the centripetal nanofiber structure also had a promotional effect on the regeneration of skull base bone tissue.

Structural, Morphological, Optical and Vibrational Properties of a Novel Coral-Like Fibrous CuO Nanostructure Synthesized via Dropwise Precipitation for UV-light Induced Photocatalytic Wastewater Remediation on Aqueous R6G Dye

CuO is a well-known monoclinic structure with unique properties that is extensively investigated for sensor, energy storage, and optoelectronic applications. In this work, the CuO nanostructure was synthesized through facile precipitation by mixing the aqueous copper (II) sulfate pentahydrate with sodium hydroxide. The as-synthesized CuO was characterized by scanning electron microscopy (SEM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and UV–visible spectroscopy. A homogeneous growth of a narrow, fine coral-like fibrous morphology was observed on CuO under SEM imaging. The FTIR spectra reveal the existence of some dominant sharp bands in the lower wavenumber region that represent the Cu-O bonds. The high solubility of CuO in water confirms the formation of particles with nanoscale dimensions. CuO exhibits a strong optical absorption peak at 510 nm, and the band gap determined by Tauc's relation is 2.11 eV. CuO is capable of inducing photocatalytic degradation on R6G dye solutions under low-intensity UVC irradiation, which can serve as a future photocatalyst for wastewater treatment.

Multi-Gradient Bone-Like Nanocomposites Induced by Strain Distribution.

The heterogeneity of bones is elegantly adapted to the local strain environment, which is critical for maintaining mechanical functions. Such an adaptation enables the strong correlation between strain distributions and multiple gradients, underlying a promising pathway for creating complex gradient structures. However, this potential remains largely unexplored for the synthesis of functional gradient materials. In this work, heterogeneous bone-like nanocomposites with complex structural and compositional gradients comparable to bones are synthesized by inducing strain distributions within the polymer matrix containing amorphous calcium phosphate (ACP). Uniaxial stretching of composite films exerts the highest strain in the center, which ceases gradually toward the sides, resulting in the gradual decrease of polymer alignment and crystallinity. Simultaneously, the center with high orientation traps most ACP during stretching due to the nanoconfinement effect, which in turn promotes the formation of aligned nanofibrous structures. The sides experiencing the least strain have the smallest amounts of ACP, characteristic of porous architectures. Further crystallization of ACP produces oriented apatite nanorods in the center with a larger crystalline/amorphous ratio than the sides because of template-induced crystallization. The combination of structural and compositional gradients leads to gradient mechanical properties, and the gradient span and magnitude correlate nicely with strain distributions. Accompanying bone-like mechanical gradients, the center is less adhesive and self-healable than the sides, which allows a better recovery after a complete cutting. Our work may represent a general strategy for the synthesis of biomimetic materials with complex gradients thanks to the ubiquitous presence of strain distributions in load-bearing structures.

Piezoelectric silk fibroin nanofibers: Structural optimization to enhance piezoelectricity and biostability for neural tissue engineering

Silk fibroin (SF) has garnered significant interest in tissue engineering due to its excellent biocompatibility and bioactivity. Notably, SF exhibits piezoelectric properties that can be harnessed to electrically stimulate cells, enhancing tissue morphogenesis. However, a systematic approach to control SF's piezoelectricity and biodegradation, and its application in neural morphogenesis, has not been fully explored. In this study, SF was electrospun into nanofibers of various sizes and subjected to a post-electrospinning chemical treatment to examine the effects of phase composition, especially the β-sheet formation, on the piezoelectricity and biostability of SF. The optimized SF scaffolds having a nanofiber diameter of 750 nm and a scaffold thickness of 250 µm allowed for the maintenance of nanofibrous structure for at least 6 weeks in aqueous environments while maintaining piezoelectric potential outputs of at least 200 mVp-p. This enabled cell membrane depolarization over an extended cell culture duration, facilitating the functional maturation of human neural stem cells (hNSCs). Specifically, acoustic piezo-activation of the SF scaffolds, resulting in mechano-electrical stimulation (MES) of the cells, accelerated their differentiation into neurons, astrocytes, and especially oligodendrocytes, leading to robust axon myelination within two weeks. Furthermore, MES enhanced neural connectivity and functional maturity, as evidenced by significant increases in excitatory and inhibitory synapse formation (46 % and 58 %, respectively), action potential amplitude (252 %), and velocity (210 %) compared to static control conditions. These findings demonstrate the potential of biodegradable electrospun SF nanofibers with balanced piezoelectricity and biostability for advancing neural tissue engineering.

Optimizing Ammonia Detection with a Polyaniline-Magnesia Nano Composite.

Polyaniline-magnesia (PANI/MgO) composites with a fibrous nanostructure were synthesized via in situ oxidative polymerization, enabling uniform MgO integration into the polyaniline matrix. These composites were characterized using FTIR spectroscopy to analyze intermolecular bonding, XRD to assess crystallographic structure and phase purity, and SEM to examine surface morphology and topological features. The resulting PANI/MgO nanofibers were utilized to develop ammonia (NH3) gas-sensing probes with evaluations conducted at room temperature. The study addresses the critical challenge of achieving high sensitivity and selectivity in ammonia detection at low concentrations, which is a problem that persists in many existing sensor technologies. The nanofibers demonstrated high selectivity and optimal sensitivity for ammonia detection, which was attributed to the synergistic effects between the polyaniline and MgO that enhance gas adsorption. Furthermore, the study revealed that the MgO content critically influences both the morphology and the sensing performance, with higher MgO concentrations improving sensor response. This work underscores the potential of PANI/MgO composites as efficient and selective ammonia sensors, highlighting the importance of MgO content in optimizing material properties for gas-sensing applications.

Methods for increasing productivity of AC-electrospinning using weir-electrode

The presented work brings new knowledge in the field of spinning electrodes for AC‑electrospinning technology, which is used for producing nanofibrous structures using a solution of polyvinyl butyral. It presents new types of spinning weir‑electrodes and describes research on the influence of electrode design parameters on the stability of the spinning process and the productivity of nanofiber production. The multistage spinning electrode is presented in the ratio of stages one to five. Research is also focused on the effect of the parameters of the electric signal used as a source for the spinning electrode on spinning stability and productivity. Observed parameters were voltage level, frequency and shape such as sine wave, rectangle wave and modified sine wave. An analysis of the influence of the spinning conditions on the resulting nanofibrous structure was also performed by analyzing results gained by SEM; the defects were investigated mainly. The results of the research presented in the thesis open up new possibilities for follow-up research in the field of AC-electrospinning.

Preparation of biocompatible Zein/Gelatin/Chitosan/PVA based nanofibers loaded with vitamin E-TPGS via dual-opposite electrospinning method

Wound management is a critical aspect of healthcare, necessitating effective and innovative wound dressing materials. Many existing wound dressings lack effectiveness and exhibit limitations, including poor antimicrobial activity, toxicity, inadequate moisture regulation, and weak mechanical performance. The aim of this study is to develop a natural-based nanofibrous structure that possesses desirable characteristics for use as a wound dressing. The chemical analysis confirmed the successful creation of Zein (Ze) (25% w/v) /gelatin (Gel) (10% w/v) /chitosan (CS) (2% w/v) /Polyvinyl alcohol (PVA) (10% w/v) nanofibrous scaffolds loaded with vitamin E tocopheryl polyethylene glycol succinate (Vit E). The swelling percentages of nanofiber (NF), NF + Vit E, cross-linked nanofiber (CNF), and CNF + Vit E were 49%, 110%, 410%, and 676%, respectively; and the degradation rates of NF, NF + Vit E, CNF, and CNF + Vit E were 29.57 ± 5.06%, 33.78 ± 7.8%, 14.03 ± 7.52%, 43 ± 6.27%, respectively. The antibacterial properties demonstrated that CNF impregnated with antibiotics reduced Escherichia coli (E. coli) counts by approximately 27–28% and Staphylococcus aureus (S. aureus) counts by about 34–35% compared to negative control. In conclusion, cross-linked Ze/Gel/CS/PVA nanofibrous scaffolds loaded with Vit E have potential as suitable wound dressing materials because environmentally friendly materials contribute to sustainable wound care and controlled degradation ensures wound dressings breakdown harmlessly.

Effective removal of Calcium and Magnesium Ions from boiler feed Water using Polyacrylonitrile supported titanium tungstovanadate composite ion exchange nanofiber

&lt;p&gt;&lt;em&gt;&lt;strong&gt;​​​​​​&lt;/strong&gt;&lt;/em&gt;&lt;span style="font-family:&amp;quot;Times New Roman&amp;quot;,&amp;quot;serif&amp;quot;;font-size:12.0pt;line-height:150%;"&gt;The challenge posed by the presence of calcium ions (Ca&lt;sup&gt;2+&lt;/sup&gt;) in process streams is attributed to its adverse effects on the heat transfer efficiency of process equipment. In this study, a novel electrospun nanofibrous composite was synthesized by combining polyacrylonitrile (PAN) with well-dispersed Titanium tungestovanadate (TWV) cation exchanger. Homogeneous precipitation technique was employed to synthesize nano-titanium (IV) tungstovanadate (TWV) cation exchanger. Various synthesis parameters, including reactant volume ratio, amount of precipitating agent and reaction temperature, were optimized to achieve the highest ion exchange capacity (IEC). The prepared ion exchange material exhibited an ion exchange capacity (IEC) of 2.39 meq.g&lt;sup&gt;-1&lt;/sup&gt; for Na&lt;sup&gt;+&lt;/sup&gt; ions. The incorporation of the prepared nanoparticles into nanofibers conferred the sorption capabilities of the composite. The nanofibers' morphologies and structures were analyzed using Fourier transform infrared (FTIR), scanning electron microscopy (SEM), and X-ray diffraction (XRD). Batch sorption experiments were carried out to investigate the sorption properties. Controlled experiments were conducted to investigate the impact of various factors, including solution pH, temperature, dosage, contact time, and the initial concentration of the hard water. The results indicated that the optimum adsorption conditions that gave the highest percentage of removal 99%, 98% for Ca&lt;sup&gt;2+&lt;/sup&gt; and Mg&lt;sup&gt;2+&lt;/sup&gt;&amp;nbsp; ions respectively were 50 mg of adsorbent dosage, 500 ppm of Ca&lt;sup&gt;2+&lt;/sup&gt; and Mg&lt;sup&gt;2+&lt;/sup&gt;&amp;nbsp; solution =7, and a contact time of 30 min at room temperature .The &amp;nbsp;kinetic data were fitted to pseudo second order model. Furthermore, the thermodynamic study suggested that the adsorption on PAN/TWV NF was endothermic and spontaneous.&lt;/span&gt;&lt;/p&gt;

Electric field simulation, structure and properties of nanofiber- coated yarn prepared by multi-needle water bath electrospinning.

To address the issue of low yield in the preparation of nanofiber materials using single-needle electrospinning technology, multi-needle electrospinning technology has emerged as a crucial solution for mass production. However, the mutual interference of multiple electric fields between the needles can cause significant randomness in the morphology of the produced nanofibers. To better predict the influence of electric field distribution on nanofiber morphology, simulation analysis of the multi-needle arrangement was conducted using finite element analysis software. Nanofiber-coated yarn was produced continuously with the core yarn rotating. The water bath was utilized as the receiver of nanofibers on self-made water bath electrospinning equipment. The electric field distribution and mutual interference under seven different needle arrangements was simulated and analyzed by finite element analysis software ANSYS Maxwell. The results indicated that when the needles were arranged diagonally in a staggered pattern and directly above the core yarn, the simulated electric field distribution was relatively uniform, with less mutual interference. The produced nanofibers exhibited a finer diameter and the diameter distribution was more concentrated. In addition, the nanofiber coating showed higher crystallinity and better mechanical properties.&#xD.

High-Speed Electrospinning of Ethyl Cellulose Nanofibers via Taylor Cone Optimization.

Ethyl cellulose (EC) is one of the most widely used cellulose derivatives. Nevertheless, challenges such as the formation of beaded fibers, low yield, and nonporous internal structure persist in electrospinning, limiting functional improvements and industrial applications. This study invented a groundbreaking high-speed electrospinning technique through sheath liquid assistance to optimize the Taylor cone, dramatically enhancing the yield, morphology, and formation of porous structures of EC nanofibers beyond what has been seen in the literature to date. Our study emphasizes the crucial role of the sheath liquid's physical and chemical properties in controlling the morphology and diameter of EC nanofibers. It was discovered that highly polar and viscous sheath liquids led to the formation of beaded structures. Most importantly, the sheath liquid-assisted method substantially increased the ejection rate of the EC solution tens and hundreds of times compared to the current low-speed electrospinning method (0.1-1 mL/h) by refining the shape of the Taylor cone and resolving low productivity challenges in conventional nanofiber production. Meanwhile, increasing the flow rate of the EC or the sheath liquid accelerated the phase separation of EC solutions, thereby promoting the formation of porous structures in EC nanofibers. A pronounced porous structure was observed when the core EC flow rate reached 25 mL/h or the sheath chloroform flow rate reached 20 mL/h. Furthermore, our sheath liquid-assisted high-speed electrospinning technique demonstrated universal applicability to ECs with varying molecular weights. This study comprehensively addressed challenges in controlling the yield, morphology, and internal structure of EC nanofibers through sheath-solution-assisted high-speed electrospinning technology. These findings provide an innovative approach to developing next-generation electrospinning technologies to enhance the yield and properties of natural polymers for sustainability.

Hybrid organic - inorganic filter system for cadmium ions adsorption from aqueous solutions

The study reflects on the problem of heavy metals, namely cadmium, polluting the natural environment. The goal was to select the most efficient adsorber enabling ion exchange between calcium and cadmium in an aqueous environment and subsequently design a material hybrid organic-inorganic, particle-fiber system that adsorbs cadmium from aqueous environments and will be easily included in the technological process. The novelty of this study lies in the use of waste food material – eggshells as a source of biogenic nanoparticles. These are applied to a nanofibrous structure made of polyvinyl butyral in amounts of 8 to 10 %wt by weight by the AC electrospinning. (The experiment was performed with these boundary conditions: temperature was 23°C, and humidity was 42%. The high-electrical voltage amplifier generated a sinusoidal waveform with a frequency of 50 Hz and an amplitude of 32 kV) and were used for ion exchange. In ion exchange, cadmium ions are exchanged with calcium ions based on the principle of chemical similarity of the two elements expressed by the z/r ratio (charge/ radius ratio), the z/r ratio is 2.02 for calcium ions Ca2+ and 2.06 for cadmium Cd2. Separateted nanoparticles of calcium carbonate obtained by burning eggshells (727°C) with dimensions from 100 to 200 nm and a specific surface area of 3.9 m2/g showed the highest adsorption capacity of 99.8%, synthetic calcium carbonate at 71.8%, and ground eggshells the lowest at 25.0%. Designed and laboratory-tested filter system of nanoparticles - nanofibers captures 95.6% and 96.8% of cadmium ions from an aqueous solution within 10 minutes and 90 minutes, respectively, at a concentration of cadmium ions of 10 mg/l, and at several nanoparticles of 0.3 g. The ion exchange is carried out only on the filter surface, and after a specific time, the calcium carbonate nanoparticles are released from the filter probably due to absence of chemical bond between nanoparticles and nanostructures or the low density of the nanofibrous structure. SEM, EDX, FTIR, BET and TGA analysis were used for material evaluation. The adsorption capacity of used nanoparticles and filter adsorbers was evaluated according to residual amounts of cadmium ions in aqueous solutions using ICP-IOS.

Preparation of starch-based oral fast-disintegrating nanofiber mats for astaxanthin encapsulation and delivery via emulsion electrospinning

Developing green and efficient delivery systems to promote bioavailability of bioactive ingredients is a sustained demand in food industry. In this work, the astaxanthin (AST)-loaded starch-based fast-dissolving nanofibers with core-shell structure were prepared by emulsion electrospinning technique without using any organic solvent. To load water-insoluble AST in hydrophilic octenyl succinic anhydride starch (OSAS)/polyvinyl alcohol (PVA) nanofiber matrices, AST-loaded nanoscale emulsions (212.19 ± 5.63 nm) with high encapsulation efficiency (91.54 ± 0.14 %) were prepared as a precursor for emulsion electrospinning, using OSAS/PVA aggregates as an emulsifier. The core-shell structure of nanofibers was revealed by the Transmission electron microscopy (TEM), with average diameter of 509.58 ± 12.77 nm, and 88.64 ± 0.49 % for AST were effectively encapsulated in core layer. Nanofiber mats exhibited high encapsulation efficiency (85.11 ± 1.53 %) and excellent storage stability over 7 d. Meanwhile, amorphous transformation of AST enabled it possess higher water solubility, bioaccessibility, and antioxidant properties (97.72 ± 2.17 %) than free AST in aqueous system. The results demonstrated that the green, nontoxic, and biodegradable nanofiber mats prepared by emulsion electrospinning successfully realized the encapsulation and delivery of AST, with broad application prospects in the food and pharmaceutical fields.