Electrospun Polymer Nanofibers Research Articles

Label-free SERS-ML detection of cocaine trace in human blood plasma

The widespread consumption of cocaine poses a significant threat to modern society. The most effective way to combat this problem is to control the distribution of cocaine, based on its accurate and sensitive detection. Here, we proposed the detection of cocaine in human blood plasma using a combination of surface enhanced Raman spectroscopy and machine learning (SERS-ML). To demonstrate the efficacy of our proposed approach, cocaine was added into blood plasma at various concentrations and drop-deposited onto a specially prepared disposable SERS substrate. SERS substrates were created by deposition of metal nanoclusters on electrospun polymer nanofibers. Subsequently, SERS spectra were measured and as could be expected, the manual distinguishing of cocaine from the spectra proved unfeasible, as its signal was masked by the background signal from blood plasma molecules. To overcome this issue, a database of SERS spectra of cocaine in blood plasma was collected and used for ML training and validation. After training, the reliability of proposed approach was tested on independently prepared samples, with unknown for SERS-ML cocaine presence or absence. As a result, the possibility of rapid determination of cocaine in blood plasma with a probability above 99.5% for cocaine concentrations up to 10-14 M was confirmed. Therefore, it is evident that the proposed approach has the ability to detect trace amounts of cocaine in bioliquids in an express and simple manner.

Degradation profiles of the poly(ε-caprolactone)/silk fibroin electrospinning membranes and their potential applications in tissue engineering

Degradation profiles are critical for the optimal application of electrospun polymer nanofibers in tissue regeneration, wound healing, and drug delivery systems. In this study, natural and synthetic polymers and their composites were subjected to in vivo transplantation and in vitro treatment with lipases, macrophages, and acetic acid to evaluate their degradation patterns. The effects of environmental stimulation, surface wettability, and polymer components on the degradation profiles of the electrospinning poly(ε-caprolactone)/silk fibroin (PCL/SF) nanofibers were first evaluated. In vivo degradation study demonstrated that bulk degradation, characterized by the transition from microfibers to nanofibers, and surface erosion, characterized by fusion between the microfibers or direct erosion from both ends of the microfibers, occurred in the electrospun membranes; however, bulk degradation dominated their overall degradation. Furthermore, the degradation rates of the electrospun PCL/SF membranes varied according to the composition, morphology, and surface wettability of the composite membranes. After the incorporation of silk fibroin (SF), the degradation rate of the SF/PCL composite membranes was faster, accompanied by larger values of weight loss and molecular weight (Mw) loss when compared with that of the pure poly(ε-caprolactone) (PCL) membrane, indicating a close relationship between degradation rate and hydrophilicity of the electrospinning membranes. The in vitro experimental results demonstrated that enzymes and oxidation partially resulted in the surface erosion of the PCL/SF microfibers. Consequently, bulk degradation and surface erosion coordinated with each other to enhance the hydrophilicity of the electrospinning membranes and accelerate the in vivo degradation.

Quality by Design Based Development of Electrospun Nanofibrous Solid Dispersion Mats for Oral Delivery of Efavirenz

Poor aqueous solubility often results in poor dissolution behavior and, consequently, poor bioavailability for those drugs whose intestinal absorption is dissolution rate limited. It is essential for formulation scientists to identify strategies to improve the solubility and dissolution rate of candidate drugs in order to improve their bioavailability. The present study investigated electrospun polymeric nanofibers for efavirenz (an antiretroviral drug), a Class II drug in the Biopharmaceutical Classification System. In order to fabricate nanofibers, hydrophilic spinnable polymer like Soluplus was used. Statistical design of experiments was used to optimize electrospinning parameters. Scanning electron microscopy (SEM) studies confirmed the presence of nanofibrous material in the mat. The x-ray diffraction (XRD) and differential scanning calorimetry (DSC) studies advocated the amorphization of efavirenz in the nanofiber samples. The optimized nanofiber-based platform significantly improved in vitro dissolution of efavirenz (89.0 ± 3.2% in 120 minutes) compared to pure efavirenz crystals (27.3 ± 2.4%).

Dendronized Ag/Au Nanomats: Antimicrobial Scaffold for Wound Healing Bandages.

Electrospun polymer nanofibers, due to high surface area-to-volume ratio, high porosity, good mechanical strength, and ease of functionalization, appear as promising multifunctional materials for biomedical applications. Thanks to their unidirectional structure, imitating the extracellular matrix (ECM), they can be used as scaffolds for cell adhesion and proliferation. In addition, the incorporation of active groups inside nanofiber can give properties for bactericides. The proposed nanomats incorporate nanoparticles templated within the electrospun nanofibers that prevent infections and stimulate tissue regeneration. The generated hybrid electrospun nanofibers are composed of a copolymer of L-lactide-block-ε-caprolactone (PL-b-CL), 70:30, blended with homopolymer polyvinylpyrrolidone (PVP) and gold (Au) nanoparticles. A low cytotoxicity and slightly increased immunoreactivity, stimulated by the nanomat, are observed. Moreover, the decoration of the hybrid nanomat with dendronized silver nanoparticles (Dend-Ag) improves their antibacterial activity against antibiotic-resistant Pseudomonas aeruginosa. The use of Dend-Ag for decorating offers several functional effects; namely, it enhances the antibacterial properties of the produced nanomats and induces a significant increase within macrophages' cytotoxicity. The unidirectional nanostructures of the generated hybrid nanomats demonstrate unique collective physio-chemical and biological properties suitable for a wide range of biomedical applications. Here, the antibacterial properties facilitate an optimal environment, contributing to accelerated wound healing.

FcLR-Chitosan/Pullulan nanofibers: Boosted antibacterial activity and decreased cytotoxicity

Natural and environmentally benign electrospun polymeric nanofibers (NFs) with distinctive features, unique physiochemical and biological properties, and high susceptibility to carry non-toxic antibacterial cargoes, e.g., ferrocenyl-based compounds, have emerged as a neo-tool for killing bacteria. Here, the antibacterial FcLR-Chit/Pull NFs were fabricated through three steps: 1) synthesis of FcLR-Chit via the attachment of chitosan to Ferrocenyl Lawesson’s Reagent (FcLR), 2) blending of the FcLR-Chit at various concentrations with the natural polymer of pullulan, and 3) electrospinning. The successfully characterized FcLR-Chit/Pull NFs with a homogenous distribution of FcLR-Chit inside the pullulan matrix were thermally stable up to 270–290 ºC and mechanically stable with an increased elongation at break (EAB) (30.0–42.2%) and decreased tensile strength (TS) (1.1–2.3 MPa) compared to the pure pullulan NFs with the EAB of 19.0% and TS of 3.6 MPa. Pure pullulan NFs and FcLR-Chit/Pull NFs (0.1 wt%, 1.0 wt%, and 5.0 wt%) showed insignificant cytotoxicity on the fibroblast cell lines (L929). The antibacterial activity was detected in the trend of FcLR-Chit/Pull NFs (5.0 wt%)>FcLR-Chit powder (5.0 wt% in water)>FcLR-Chit/Pull NFs (1.0 wt%)>FcLR powder (5.0 wt% in water)>FcLR-Chit/Pull NFs (0.1 wt%)>chitosan powder (5.0 wt% in water)> pure pullulan NFs. The FcLR-Chit/Pull NFs (5.0 wt%) with an average diameter of 365 nm, insignificant cytotoxicity on L929 cells within 24 h and 48 h, and boosted antibacterial activity with the inhibition zone diameter of 1.95 mm against Gram-negative E. Coli and 1.76 mm against Gram-positive S. aureus bacteria were chosen as the optimal nanofibrous candidate for the future bactericidal applications.

PMMA and PVP blended nanofibers with incorporated antimicrobial agent: Spectroscopy and mass spectrometry characterization

Electrospun polymeric nanofibers incorporated with some medicines or biologically active nanoparticles have a huge range of various applications in biomedical fields such as wound dressing, drug delivery, and tissue engineering. Blending several polymers with different properties allows one to obtain a new material with improved physicochemical and mechanical characteristics, as well as to control the incorporation and release of medical agents, including antimicrobial, antifungal, and other substances. In this work, a novel approach to prepare a blend of two polymers [polyvinylpyrrolidone (PVP) and polymethyl methacrylate (PMMA)] to produce biocompatible nanofibers with incorporated antibacterial agents — phenylalanine or silver nanoparticles is proposed. The diameter of the obtained nanofibers is in the range of 2–4 μm. Antimicrobial agents are incorporated in PVP in an aqueous solution, then the prepared adduct is dried and mixed with PMMA in an organic solvent. In this nanofiber mat, PMMA provides the mechanical strength of the mat and assists in the gradual release of the antimicrobial agents. The formation of the PVP:PMMA nanofibers with incorporated antimicrobial agents at different stages was monitored by spectroscopy. The release of antimicrobial agents from the nanofibers mat during wetting was studied and confirmed by spectroscopy and mass spectrometry investigations.

A systematic review on green and natural polymeric nanofibers for biomedical applications

Electrospinning is the simplest technique to produce ultrathin nanofibers, which enables the use of nanotechnology in various applications. Nanofibrous materials produced through electrospinning have garnered significant attention in biomedical applications due to their unique properties and versatile potential. In recent years, there has been a growing emphasis on incorporating sustainability principles into material design and production. However, electrospun nanofibers, owing to their reliance on solvents associated with significant drawbacks like toxicity, flammability, and disposal challenges, frequently fall short of meeting environmentally friendly standards. Due to the limited solvent choices and heightened concerns for safety and hygiene in modern living, it becomes imperative to carefully assess the implications of employing electrospun nanofibers in diverse applications and consumer products. This systematic review aims to comprehensively assess the current state of research and development in the field of “green and natural” electrospun polymer nanofibers as well as more fascinating and eco-friendly commercial techniques, solvent preferences, and other green routes that respect social and legal restrictions tailored for biomedical applications. We explore the utilization of biocompatible and biodegradable polymers sourced from renewable feedstocks, eco-friendly processing techniques, and the evaluation of environmental impacts. Our review highlights the potential of green and natural electrospun nanofibers to address sustainability concerns while meeting the demanding requirements of various biomedical applications, including tissue engineering, drug delivery, wound healing, and diagnostic platforms. We analyze the advantages, challenges, and future prospects of these materials, offering insights into the evolving landscape of environmentally responsible nanofiber technology in the biomedical field.

Improved mRNA affinity chromatography binding capacity and throughput using an oligo-dT immobilized electrospun polymer nanofiber adsorbent

Increased demand for mRNA-based therapeutics and improved in vitro transcription (IVT) yields have challenged the mRNA purification platform. Hybridization-affinity chromatography with an immobilized oligo-deoxythymidilic acid (oligodT) ligand is often used to capture mRNA through base pairing with the polyadenylated tail. Commercially available oligodT matrices include perfusive cross-linked poly(styrene-divinylbenzene) 50 µm POROS™ chromatography resin beads and convective polymethacrylate CIMmultus® monolithic columns consisting of 2 µm interconnected channels. POROS™ columns may be limited by poor mass transfer for larger mRNAs and slow flowrates, while monoliths can operate at higher flowrates but are limited by modest binding capacity. To enable both high flowrates and binding capacity for mRNA of all lengths, prototype chromatography media was developed by Cytiva using oligodT immobilized electrospun cellulose nanofibers (Fibro™) with a 0.3–0.4 µm pore size. In this work, four polyadenylated mRNAs ranging from ∼1900–4300 nucleotides were used to compare the dynamic binding capacity (DBC) of Fibro™, POROS® and CIMmultus® columns as a function of residence time and binding buffer compositions. Fibro™ improved the DBC ∼2–4-fold higher than CIMmultus® and ∼2–13-fold higher than POROS™ across all residence times, mRNA length, and binding matrix compositions tested. CIMmultus® DBC was least dependent on residence time and mRNA size, while both Fibro™ and POROS™ DBC increased at slower flowrates and with shorter mRNA. Surprisingly, inverse size exclusion (ISE) experiments showed that POROS™ was not limited by diffusion and POROS™ along with CIMmultus® demonstrate higher mRNA permeation however the Fibro™ prototype is not in the final configuration. Lastly, IVT reaction products were subjected to purification and oligodT elution product yield, quality, and purity were consistent across the three matrices investigated. These results highlight the benefits of high DBC and equivalent product profiles offered by the oligodT Fibro™ prototype compared to commercially available oligodT media.

Preparation, design, and characterization of an electrospun polyurethane/calcium chloride nanocomposite scaffold with improved properties for skin tissue regeneration

The present research paper explores the potential of electrospun nanofibers in the promising field of skin tissue engineering. Specifically, we propose an advanced preparation and characterization of an electrospun Polyurethane/Calcium Chloride (PU/CaCl2) nanocomposite scaffold, devised to boost the scaffold’s physicochemical and biological properties for skin tissue regeneration. By incorporating CaCl2 into the PU matrix using an electrospinning process, we were able to fabricate a novel nanocomposite scaffold. The morphological examination through Field Emission Scanning Electron Microscope (FESEM) revealed that the fiber diameter of the PU/CaCl2 (563 ± 147 nm) scaffold was notably smaller compared to the control (784 ± 149 nm). The presence of CaCl2 in the PU matrix was corroborated by Fourier-Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA). Furthermore, the PU/CaCl2 scaffold exhibited superior tensile strength (10.81 MPa) over pristine PU (Tensile −6.16 MPa, Contact angle - 109° ± 1° and Roughness - 854 ± 32 nm) and revealed enhanced wettability (72° ± 2°) and reduced surface roughness (274 ± 104 nm), as verified by Contact angle and Atomic Force Microscopy. The developed scaffold demonstrated improved anticoagulant properties, indicating its potential for successful integration within a biological environment. The improved properties of the PU/CaCl2 nanocomposite scaffold present a significant advancement in electrospun polymer nanofibers, offering a potential breakthrough in skin tissue engineering. However, additional studies are required to thoroughly evaluate the scaffold’s effectiveness in promoting cell adhesion, proliferation, and differentiation. We aim to catalyze significant advancements in the field by revealing the creation of a potent skin scaffold leveraging electrospun nanofibers. Encouraging deeper exploration into this innovative electrospun composite scaffold for skin tissue engineering, the PU/CaCl2 scaffold stands as a promising foundation for pioneering more innovative, efficient, and sustainable solutions in biomedical applications.

Fabrication and characterization of shikonin and sea buckthorn endowed nanoemulsion reinforcing elecrospun scaffolds for treatment of diabetic wounds

Electrospun polymeric nanofibers represent a novel class of wound dressing owing to their structural resemblance with the natural extracellular matrix within which pro and anti-apoptotic functions can be orchestrated comprehensively resulting in effective wound management especially in case of diabetic wounds. Recent epidemiological reports demonstrate the role of matrix metalloproteinases (MMPs) as a clear indicator of recalcitrant healing in diabetic wounds that can specifically ablate the growth factors and other pro-healing molecules hindering the healing process. Beguiling the anti-inflammatory, antimicrobial, anti-diabetic and MMP-9 modulatory properties of naphthoquinone pigments, shikonin has enticed interest of researchers in diabetic wound management. Poor solubility and photosensitivity demands novel delivery of this compound for better therapeutic efficacy. The study, thus, aims to develop reinforced shikonin and sea buckthorn oil loaded nanoemulsion (SS-NE) based chitosan scaffolds by incorporation of SS-NE as nanofiller in fibers. Subsequent characterization confirmed the stability and encapsulation of shikonin in prepared scaffold system. The results of burn wound model in diabetic Wistar rats (Type 2 diabetes) indicated that the micro-nanostructure of the fiber mats was able to promote wound healing by substantially downregulating the level of MMP-9 and stimulating collagen deposition and re-epithelization. The salient findings of the present study proposed that the bioenthused asymmetric wettable scaffolds can be employed as a propitious delivery system for treatment of diabetic wounds.

Electrospun Polymer Nanofibers for Technology Applications: A Short Review

Abstract: Nanofibers are a type of nanomaterial with a diameter ranging from ten to a few hundred nanometers with a high surface-to-volume ratio and porosity. They can build a network of high-porosity material with excellent connectivity within the pores, making them a preferred option for numerous applications. This review explores nanofibers from the synthesis techniques to fabricate nanofibers, with an emphasis on the technological applications of nanofibers like water and air filtration, photovoltaics, batteries and fuel cells, gas sensing, photocatalysis, and biomedical applications like wound dressing and drug delivery. The nanofiber production market has an expected compound annual growth rate (CAGR) of 6% and should reach around 26 million US $ in 2026. The limitations and potential opportunities for large-scale applications of nano-fibrous membranes are also discussed. We expect this review could provide enriched information to better understand Electrospun Polymer Nanofiber Technology and recent advances in this field.

Piezoelectric Properties of Electrospun Polymer Nanofibers and Related Energy Harvesting Applications

AbstractElectrospinning (ES) methods that can produce piezoelectricity in polymer nanofibers have attracted tremendous research attention. These electrospun polymer nanofibers can be employed for sensors, energy harvesting, tissue engineering, and filtration applications. This paper reviews the performance of a variety of electrospun piezoelectric polymer nanofibers produced by different ES methods, including near‐field electrospinning and conventional far‐field electrospinning methods. Herein, it is described how the ES method can affect the piezoelectric properties of various polymer nanofibers, including poly(vinylidene difluorine), poly(vinylidene fluoride‐trifluoroethylene), nylon 11, poly(l‐lactic acid), and poly(α‐benzyl‐l‐glutamate). Due to the varied matrix structures of piezoelectric polymer nanofibers, the ES method may conduct variable effects on the piezoelectric properties of polymer nanofibers. After characterizations by X‐ray diffraction, Fourier transform infrared spectrum, dielectric spectra, and piezoelectric coefficient measurements, it is found that the piezoelectric properties of the polymer nanofibers can be significantly affected by the ES parameters. Most of previous review articles focus on the output performance of electrospun polymer nanofibers. A detailed description of how different ES methods affect the piezoelectricity of polymer nanofibers is still lacking. In this review paper, the basic principle behind ES methods and the way in which different ES methods affect the properties of polymer nanofibers are examined.

Improved antitumor activity through a tyramidyl maslinic acid derivative. Design and validation as drug-loaded electrospun polymeric nanofibers

Among the most harmful tumors detected in the human body, such as breast, colon, brain or pancreas, breast (BC) and colorectal cancer (CRC) are the first and third most frequent cancer worldwide, respectively. The current existing chemotherapeutic treatments present serious side effects due to their intravenous administration can induce cytotoxicity in healthy cells. Thus, new treatment methods based on drug-loaded polymeric nanofibers (NFs) have gained significant potential for their use in localized cancer chemotherapy. Here, a deep in vitro comparative analysis between maslinic acid (MA) and a tyramine-maslinic acid (TMA) derivative is initially performed. This analysis includes a proliferation, and a cell cycle assay, and a genotoxicity, antiangiogenic and apoptosis study. Then, the TMA derivative has been incorporated into electrospun polymeric NFs obtaining an implantable dressing material with antitumor activity. Two types of patches containing TMA-loaded polymeric NFs of poly(caprolactone) (PCL), and a mixture of polylactic acid/poly(4-vinylpyridine) (PLA/PVP) were fabricated by the electrospinning technique. The characterization of the drug-loaded NFs showed an encapsulation capacity of 0.027 mg TMA/mg PCL and 0.024 mg TMA/mg PLA/PVP. Then, the cytotoxic activity of both polymeric systems was tested in CRC (T84), BC (MCF-7) and a no tumor (L929) cell lines exposed to TMA-loaded NFs and blank NFs for 48 h. Moreover, cell cycle assay, genotoxicity, angiogenesis and apoptosis tests were carried out to study the mechanism of action of TMA. Blank NFs showed no-toxicity in all cell lines tested and both drug-loaded NFs significantly reduced cell proliferation (relative proliferation of ≈44 % and ≈25 % respectively). Therefore, TMA was less genotoxic than maslinic acid (MA), and reduced VEGFA expression in MCF-7 cells (1.32 and 2.12-fold for MA and TMA respectively). These results showed that TMA-loaded NFs could constitute a promising biocompatible and biodegradable nanoplatform for the local treatment of solid tumors such as CRC or BC.

Fabrication of Activated Multiporous Carbon Nanofibers Using Vacuum Plasma for High-Capacity Energy Storage

Porous carbon nanofibers are widely used as supercapacitor electrode materials due to their excellent physical adsorption/desorption operation and smooth transport of ions. The acid/base activation method is commonly used to generate micropores on the surface of carbon nanofibers, but controlling the activation level and minimizing the release of harmful chemicals pose challenges. This study proposed a method for producing activated multiporous carbon nanofibers that is easier to operate and more environmentally friendly. It utilizes the vacuum plasma process to enhance surface area and introduce functional groups onto the electrospun polymer nanofibers. Subsequent heat treatment results in the formation of activated multiporous carbon nanofibers. The type and density of the functional group introduced into the carbon structure were adjusted to the type of plasma gas (O2, NH3 and C4F8) being exposed. Among them, oxygen plasma-treated carbon nanofibers (O-MPCNFs) not only have a much larger active surface (517.84 m2 g−1) than other gases (290.62 m2 g−1 for NH3 and 159.29 m2 g−1 for C4F8), but also generate a lot of micropores, promoting rapid adsorption/desorption-inducted charges; therefore, they have excellent energy storage capacity. The O-MPCNF-based symmetrical two-electrode supercapacitor has a high specific capacitance (173.28 F g−1), rate capability and cycle stability (94.57% after 5000 cycles).

Novel Electrospun Polymeric Nanofibers Loaded Different Medicaments as Drug Delivery Systems for Regenerative Endodontics.

A combination of antibiotics, including metronidazole (MET), ciprofloxacin (CIP), and minocycline (MINO), has been demonstrated to disinfect bacteria in necrotic teeth before regenerative processes. It has been presented clinically that antibiotic pastes may drive to possible stem cell death, creating difficulties in removing from the canal system, which can limit the regenerative procedure. This study was designed to (1) synthesize nanofibrous webs containing various concentrations of different medicaments (triple, double, and calcium hydroxide, Ca(OH)2), and (2) coat the electrospun fibrous gutta-percha (GP) cones. Poly(vinylpyrrolidone) (PVP)-based electrospun fibrous webs were processed with low medicament concentrations. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray photoelectron spectroscopy (XPS) were carried out to investigate fiber morphology and antibiotic incorporation, and characterize GP-coated fibrous webs, respectively. The chemical and physical properties of dentine were determined via fourier transform infrared spectroscopy (FTIR) and Nano-SEM, respectively. The antimicrobial properties of the different fibrous webs were assessed against various bacteria by direct nanofiber/bacteria contact. Cytocompatibility was measured by applying the MTT method. The mean fiber diameter of the experimental groups of medicament-containing fibers ranged in the nm scale and was significantly smaller than PVP fibers. EDX analysis confirmed the presence of medicaments in the nanofibers. XPS analysis presented a complete coating of the fibers with GPs; FTIR and Nano-SEM showed no chemical and physical configuration of intracanal medicaments on the dentine surface. Meanwhile, nanofibrous webs led to a significant reduction in the percentage of viable bacteria compared to the negative control and PVP. Our findings suggest that TA-NFs, DA-NFs, and Ca(OH)2)-NFs coated GP cones have significant potential in eliminating intracanal bacteria, having cell-friendly behavior and clinical usage features.

Development of Electrospun Polymer Nanofiber Membrane Based on PAN/PVDF as a Supercapacitor Separator

Among various types of energy storage, the supercapacitor is regarded as the most promising device due to its long cycling life, good cycling stability, and high power density. A supercapacitor is generally composed of electrodes, electrolytes, and a separator. The separator is one of the most important components, serving to prevent internal short circuits between the anode and the cathode. Herein, a nanostructured-based separator in a PAN/PVDF nanofiber scheme is introduced for improving the electrochemical performance of the supercapacitor. Briefly, the membranes were produced via the electrospinning technique. All of the raw materials were blended in various compositions of PVDF for optimization purposes. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were carried out to identify the microstructure of the nanofibers. The electrochemical properties of the membrane were measured using galvanostatic charge-discharge (GCD). Based on GCD, it was shown that the PAN/PVDF 20 wt% membrane exhibited the optimum gravimetric capacitance at 54.104 Fg-1 as evidenced by a high porosity percentage. Thus, the PAN/PVDF nanofiber has good potential as a separator for application in supercapacitors.

Incorporation and Deposition of Spin Crossover Materials into and onto Electrospun Nanofibers.

We synthesized iron(II)-triazole spin crossover compounds of the type [Fe(atrz)3]X2 and incorporated and deposited them on electrospun polymer nanofibers. For this, we used two separate electrospinning methods with the goal of obtaining polymer complex composites with intact switching properties. In view of possible applications, we chose iron(II)-triazole-complexes that are known to exhibit spin crossover close to ambient temperature. Therefore, we used the complexes [Fe(atrz)3]Cl2 and [Fe(atrz)3](2ns)2 (2ns = 2-Naphthalenesulfonate) and deposited those on fibers of polymethylmethacrylate (PMMA) and incorporated them into core-shell-like PMMA fiber structures. These core-shell structures showed to be inert to outer environmental influences, such as droplets of water, which we purposely cast on the fiber structure, and it did not rinse away the used complex. We analyzed both the complexes and the composites with IR-, UV/Vis, Mössbauer spectroscopy, SQUID magnetometry, as well as SEM and EDX imaging. The analysis via UV/Vis spectroscopy, Mössbauer spectroscopy, and temperature-dependent magnetic measurements with the SQUID magnetometer showed that the spin crossover properties were maintained and were not changed after the electrospinning processes.

A novel adenosine triphosphate (ATP) biosensor based on electrospun polymer nanofibers with entrapped hexokinase and glucose oxidase

A novel adenosine triphosphate (ATP) biosensor based on electrospun polymer nanofibers with entrapped hexokinase and glucose oxidase

Development of Novel Pharmaceutical Forms of the Marine Bioactive Pigment Echinochrome A Enabling Alternative Routes of Administration.

Echinochrome A (EchA), a marine bioactive pigment isolated from various sea urchin species, is the active agent of the clinically approved drug Histochrome®. EchA is currently only available in the form of an isotonic solution of its di- and tri-sodium salts due to its poor water solubility and sensitivity to oxidation. Electrospun polymeric nanofibers have lately emerged as promising drug carriers capable of improving the dissolution and bioavailability of drugs with limited water solubility. In the current study, EchA isolated from sea urchins of the genus Diadema collected at the island of Kastellorizo was incorporated in electrospun micro-/nanofibrous matrices composed of polycaprolactone and polyvinylpyrrolidone in various combinations. The physicochemical properties of the micro-/nanofibers were characterized using SEM, FT-IR, TGA and DSC analyses. The fabricated matrices exhibited variable dissolution/release profiles of EchA, as evidenced in in vitro experiments using gastrointestinal-like fluids (pH 1.2, 4.5 and 6.8). Ex vivo permeability studies using the EchA-loaded micro-/nanofibrous matrices showed an increased permeation of EchA across the duodenum barrier. The results of our study clearly show that electrospun polymeric micro-/nanofibers represent promising carriers for the development of new pharmaceutical formulations with controlled release, as well as increased stability and solubility of EchA, suitable for oral administration, while offering the potential for targeted delivery.

Hydrogen Production, Purification, Storage, Transportation, and Their Applications: A Review

The world is looking for clean and green energy as substitution for fossil fuels to minimize the greenhouse effect and climate changes threatening our existence. Solar energy, wind energy, and hydrogen gas‐based energy are few examples of promising sources of energy alternatives to fossil fuels. Hydrogen gas‐based energy is in focus today due to its availability in plenty of combined forms such as water, hydrocarbons, natural gases, etc. However, its storage and transportation are major challenges due to the low volumetric density and explosive nature of hydrogen. The scientific community is in search of suitable, economically viable, and energy‐efficient storage systems and transportation of hydrogen gas. Based on numerous studies, surface adsorption of hydrogen by high surface area nanoporous solids such as carbon and metal–organic framework (MOF)‐based nanofiber materials are most suitable for storage applications. Electrospinning process provides a gateway for the preparation of lightweight, highly porous nanofibers for efficient hydrogen adsorption. Herein, the production and use of electrospun polymer nanofibers and MOFs for the storage and transportation of hydrogen are presented.