Electrospinning Equipment Research Articles

Efficacy and Safety Evaluation of Tacrolimus-Eluting Stent in a Porcine Coronary Artery Model.

A drug-eluting stent (DES) is a highly beneficial medical device used to widen or unblock narrowed blood vessels. However, the drugs released by the implantation of DES may hinder the re-endothelialization process, increasing the risk of late thrombosis. We have developed a tacrolimus-eluting stent (TES) that as acts as a potent antiproliferative and immunosuppressive agent, enhancing endothelial regeneration. In addition, we assessed the safety and efficacy of TES through both in vitro and in vivo tests. Tacrolimus and Poly(lactic-co-glycolic acid) (PLGA) were applied to the metal stent using electrospinning equipment. The surface morphology of the stent was examined before and after coating using a scanning electron microscope (SEM) and energy dispersive X-rays (EDX). The drug release test was conducted through high-performance liquid chromatography (HPLC). Cell proliferation and migration assays were performed using smooth muscle cells (SMC). The stent was then inserted into the porcine coronary artery and monitored for a duration of 4weeks. SEM analysis confirmed that the coating surface was uniform. Furthermore, EDX analysis showed that the surface was coated with both polymer and drug components. The HPCL analysis of TCL at a wavelength of 215nm revealed that the drug was continuously released over a period of 4weeks. Smooth muscle cell migration was significantly decreased in the tacrolimus group (54.1% ± 11.90%) compared to the non-treated group (90.1% ± 4.86%). In animal experiments, the stenosis rate was significantly reduced in the TES group (29.6% ± 7.93%) compared to the bare metal stent group (41.3% ± 10.18%). Additionally, the fibrin score was found to be lower in the TES group compared to the group treated with a sirolimus-eluting stent (SES). Similar to SES, TES reduces neointimal proliferation in a porcine coronary artery model, specifically decreasing the fibrins score. Therefore, tacrolimus could be considered a promising drug for reducing restenosis and thrombosis.

Analysis of morphological properties of fibrous electrospun polyurethane grafts using image segmentation

The concentration of the polymer in the electrospinning solution greatly influences the mechanical behaviour of electrospun vascular grafts due to the influence on scaffold morphology. The scaffold morphology (fiber diameter, fiber orientation and inter-fiber voids) of the grafts plays an important role in their behaviour during use. Even though manual methods and complex algorithms have been used so far for characterisation of the morphology of electrospun architecture, they still have several drawbacks that limit their reliability. This study therefore uses conventional, statistical region merging and a hybrid image segmentation algorithm, to characterise the morphology of the electrospun vascular grafts. Consequently, vascular grafts were fabricated using an in-house electrospinning equipment using three polymer material concentration levels (14%, 16% and 18%) of medical-grade thermoplastic polyurethane (Pellethane®). The image thresholding and segementation algorithms were then used for segmentation of SEM images extracted from the polymer grafts and then morphological parameters were investigated in terms of fiber diameter, fiber orientation, and interfiber spaces (pore area and porosity). The results indicate that electrospun image segmentation was "best" when the hybrid algorithm and the conventional algorithm was used, which implied that fiber property values computed from the hybrid algorithm were closed to the manually measurements especially for the 14% PU with fiber diameter 2.2%, fiber orientation 7.6% and porosity at 1.9%. However there was higher disperity between the manual and hybrid algorithm. This suggests more fiber uniformity in the 14%PU potentially affected the accuracy of the hybrid algorithm.

In vitro evaluation and characterization of cisplatin loaded nanofibers for local chemotherapy

Cancer is a disease that affects the quality of life of the patients that are treated with Cisplatin (CDDP), which is needed for adjuvant therapy, however it leads to many secondary and adverse effects. In this study, we manufactured and characterized poly-(lactic acid) (PLA) non-woven fibers loaded with Cisplatin (CDDP) by electrospinning technique to evaluate their cytotoxicity in in vitro assays on HeLa cells (cervical carcinoma cell line). PLA–CDDP solutions with increasing concentrations of CDDP (0.5, 1 and 2% w/w) were used in a TL-01 electrospinning equipment with the same system parameters. We analyzed the chemical, thermal and morphological characteristics of PLA and PLA–CDDP fiber mats. Furthermore, hydrolytic degradation, hemolysis and toxicity in HeLa cells were evaluated. By adding the CDDP to the fibers, the degradation, glass transition and melting temperatures were modified; the 3 µm fiber diameter of pristine PLA fibers was decreased in half the size and the degradation time was extended over 5 months. However, the hemocompatibility of the material with and without CDDP was maintained, while cytotoxicity in HeLa cells increased in the three concentrations of fiber mats of PLA–CDDP compared to the intravenous drug at 24 h (p < 0.01). We concluded that the fiber mats PLA–CDDP could be used for localized therapy in the adjuvant treatment when resection panels are expose after a surgical extirpation of solid tumors.

A study on MMG sensor using piezoelectric polymer nanofibers by electrospinning

AbstractIn the fields of medical and sports science, it is required to evaluate muscle activity qualitatively and quantitatively. Currently, mechanomyogram (MMG) that can reflect the mechanical activity of muscle fibers is attracting attention. The purpose of this study is to develop a sensor that can measure MMG during exercise. In this study, a small and flexible MMG sensor using P(VDF/TrFE), which is a piezoelectric polymer material, spun into nanofibers by the electrospinning method has been fabricated and evaluated. By the fabricated electrospinning equipment and the obtained fabrication conditions of the nanofibers MMG sensor has been fabricated by using piezoelectric polymer fibers. By using nanofiber nonwoven fabric for the sensor element, the flexible sensor has been realized. In a sound wave reception experiment assuming MMG measurement, the P(VDF/TrFE) nonwoven fabric element showed that the element detected the sound pressure. Additionally, MMG during isometric contraction and pedaling motion has been measured using the fabricated sensor. The results show that the proposed sensor is effective for measuring MMG during exercise.

High-performance SiO2 nanofiber membrane applied for high-temperature air filtration

This study is focused on the development of a foldable SiO2 membrane with a monodisperse fiber diameter of 300 nm, a flexible quartz crystalline phase, high mechanical strength, and excellent thermal stability up to 1000 °C. The fabrication process was scaled up using a pilot electrospinning equipment to produce a membrane with an area of approximately 2000 m2. At room temperature, the membrane with a basis weight of 12 g/m2 and a pressure drop of 271.5 Pa exhibited filtration efficiencies of 0.9957 for the MPPS (166 nm) and 0.9988 for PM0.3 (300 nm), resulting in quality factors of 0.020 and 0.025 Pa−1, respectively. To evaluate the performance of these membranes in high-temperature air filtration processes, 25 °C, 300 °C, and 400 °C were explored. Our results indicate a high influence on nanoparticle retention and pressure drop under such conditions. For fine particles, even a 5 g/m2 membrane showed the same efficiency as a HEPA filter with twice a low pressure drop and fifteen times a low basis weight. Compared to the commercial HEPA filters, our SiO2 membrane offered the same efficiency with superior permeability, resulting in lower energy consumption and longer filtration time to reach saturation capacity. In addition, manufacturing the membranes required a reduced amount of material per unit area, resulting in significant material savings.

Unveiling the Mechanism of the in Situ Formation of 3D Fiber Macroassemblies with Controlled Properties.

Electrospinning technique is well-known for the generation of different fibers. While it is a "simple" technique, it lies in the fact that the fibers are typically produced in the form of densely packed two-dimensional (2D) mats with limited thickness, shape, and porosity. The highly demanded three-dimensional (3D) fiber assemblies have been explored by time-consuming postprocessing and/or complex setup modifications. Here, we use a classic electrospinning setup to directly produce 3D fiber macrostructures only by modulating the spinning solution. Increasing solution conductivity modifies electrodynamic jet behavior and fiber assembling process; both are observed in situ using a high-speed camera. More viscous solutions render thicker fibers that own enhanced mechanical stiffness as examined by finite element analysis. We reveal the correlation between the universal solution parameters and the dimensionality of fiber assemblies, thereof, enlightening the design of more "3D spinnable" solutions that are compatible with any commercial electrospinning equipment. After a calcination step, ultralightweight ceramic fiber assemblies are generated. These inexpensive materials can clean up exceptionally large fractions of oil spillages and provide high-performance thermal insulation. This work would drive the development and scale-up production of next-generation 3D fiber materials for engineering, biomedical, and environmental applications.

State Recognition of Multi-Nozzle Electrospinning Based on Image Processing

The online monitoring of a multi-jet electrospinning process is critical to the achievement of stable mass electrospinning for industrial applications. In this study, the construction of an ejection state recognition system of a multi-jet electrospinning process based on image processing is reported. The ejection behaviors regarding multi-nozzle electrospinning were recorded by CMOS industrial cameras in real time. The characteristic information regarding the multi-jet cone tip was obtained by processing the images regarding Roberts operator edge detection, Hough transform line detection, and mask histogram analysis. The jet anomalies of the hanging droplets in the nozzle outlet area could be obtained and identified by the vision. The identification accuracy towards the target hanging droplets was more than 85%. This work reports the intelligent control of large-scale multi-nozzle electrospinning equipment.

Simulation and experimental study of parameters in centrifugal electrospinning: Effects of rotor form on fiber formation

AbstractNanofiber is a kind of high‐performance material, which has great applications. Among many preparation methods, centrifugal electrospinning combines the advantages of electrospinning and centrifugal spinning, with high yield and a wide range of application. But its influencing factors are numerous, the process is still immature, and unable to meet the needs of industrialization. Here, we design a set of centrifugal electrospinning equipment and its process, and explore the influence of rotor form on fiber formation. First, the structure and working principle of experimental equipment of centrifugal electrospinning are introduced. Then, the influence of two factors, the rotor shape and rotor material, on space electric field is studied through theoretical and simulation analysis. Finally, based on the designed equipment, the effects of different rotor forms on the fibers preparation of centrifugal electrospinning are studied. The results show that the fiber diameter of centrifugal electrospinning is greatly affected by the form of the rotor. By changing the surface shape of the rotor and the rotor material, the diameter of the fiber can be controlled. Experiments show that the average fiber diameter of the γ‐shaped rotor is the smallest, and the fiber spun with ULTEM PEI 1010 material has the best overall performance.

Comparison of Nozzle-Based and Nozzle-Free Electrospinning for Preparation of Fast-Dissolving Nanofibers Loaded with Ciprofloxacin.

The study aimed to prepare ciprofloxacin-loaded polyvinylpyrrolidone electrospun nanofibers for oral drug delivery, using a conventional nozzle-based and a lab-built nozzle-free electrospinning equipment. To produce nanofibers, electrospinning is the process most often used. However, from the industry’s point of view, conventional electrospinning does not have sufficiently high productivity. By omitting the nozzle, productivity can be increased, and so the development of nozzle-free processes is worthwhile. In this study, a solution of ciprofloxacin and polyvinylpyrrolidone was electrospun under similar conditions, using both single-nozzle and nozzle-free methods. The two electrospinning methods were compared by investigating the morphological and physicochemical properties, homogeneity, in vitro drug release, and cytotoxicity. The stability of the nanofibers was monitored from different aspects in a 26 month stability study. The results showed that the use of the nozzle-free electrospinning was preferable due to a higher throughput, improved homogeneity, and the enhanced stability of nanofiber mats, compared to the nozzle-based method. Nevertheless, fast dissolving nanofibers loaded with poorly water-soluble ciprofloxacin were produced by both electrospinning methods. The beneficial properties of these nanofibers can be exploited in innovative drug development; e.g., nanofibers can be formulated into orodispersible films or per os tablets.

Particle morphology and antimicrobial properties of electrosprayed propolis

In this study, propolis resin was electrosprayed (ES) without a carrier polymer in order to produce nanoparticles, and the parameters affecting the ES process were investigated. During preliminary experiments, surface tension, electrical conductivity, dielectric, and rheological properties of the feed solution and their effects on electrospraying of propolis were determined. Afterward, the propolis solution was fed to the electrospinning equipment at the different feed rates (1, 5.5, and 10 ml/h), the voltages (5, 12.5, and 20 kV), and the distances to the collector plate (5, 10, and 15 cm). According to the response surface analysis (RSA), the feed rate and the applied voltage were effective for the morphology and diameter of particles. In contrast, the antimicrobial activity of particles against Staphylococcus aureus and Escherichia coli depended on the feed rate and the distance to the collector plate. Based on these results, the optimum feed rate, applied voltage, and distance to the collector plate conditions for ES of propolis were found as 8.82 ml/h, 20 kV, and 5 cm, respectively.

Full Lignin-Derived Electrospun Carbon Materials as Electrodes for Supercapacitors

In the search for more sustainable energy storage devices, biomass-derived materials have been widely researched as carbon source for electrode applications. Here we present the processing of high molecular lignin, an abundant carbon rich biopolymer and byproduct of the pulp and paper industry, into freestanding nonwoven carbon fiber (CNFs) electrodes by using electrospinning. It is worth mentioning that no petrol-derived polymers that are usually included in the electrospinning of lignin, were employed in this work, making these electrodes more sustainable than common lignin-derived carbon electrodes. The effect of the carbonization temperature and oxygen plasma treatment in the electrochemical performance of the CNFs as electrodes for supercapacitors was studied. The upscaling of the processing of lignin into carbon electrodes was also explored by comparing a standard electrospinning set up with a needleless electrospinning equipment that enabled faster and higher throughput. The electrochemical performance of the CNFs increased after plasma treatment of the surface and the electrodes prepared using the standard set up exhibited the highest activity, achieving specific capacitances of up to 103.6 F g−1.

A new versatile x\u2013y\u2013z electrospinning equipment for nanofiber synthesis in both far and near field

This work describes a versatile electrospinning equipment with rapid, independent, and precise x–y–z movements for large-area depositions of electrospun fibers, direct writing or assembly of fibers into sub-millimeter and micron-sized patterns, and printing of 3D micro- and nanostructures. Its versatility is demonstrated thought the preparation of multilayered functional nanofibers for wound healing, nanofiber mesh for particle filtration, high-aspect ratio printed lines, and freestanding aligned nanofibers.

Design, development, and experimental setup of near-field electrospinning with a sharp electrode: Influence of procedural parameters on the 3D nanofiber structure.

A near-field electrospinning configuration has been developed to fabricate 3D structures by layer-by-layer stacking. The system or experimental setup consists of a high voltage source, a syringe pump, and the electrospinning equipment which has been designed and built. It works with Arduino Uno as a controller for adjusting the procedural parameters through OpenBuilds CONTROL software using a firmware preloaded on the Arduino Uno. The proposed experimental configuration consists of a collinear arrangement between the spinner and the sharp electrode, which move in the XY directions, keeping the same disposition; this arrangement is designed with the aim of manipulating the electric field (EF) and reducing instabilities associated with the process. The displacement speed (DS) and the distance of work adjust automatically to modify nanofiber features, which improves the flexibility of the system. In order to be efficient and set the EF profile, this was simulated using COMSOL Multiphysics® software. Nylon 6,6 polymeric fiber films have been electrospun to evaluate the efficiency of the system setup and the influence of parameters. The fiber morphology is studied by scanning electron microscopy and the chemical structure features are studied by infrared spectroscopy. Parameters such as voltage and DS are studied experimentally and analyzed to determine their effects on the control of fiber deposition. Stacking of up to 15 layers was obtained where the structural characteristics notably depend on the operating parameters.

Electrospun Medicated Nanofibers for Wound Healing: Review.

With the increasing demand for wound care and treatment worldwide, traditional dressings have been unable to meet the needs of the existing market due to their limited antibacterial properties and other defects. Electrospinning technology has attracted more and more researchers’ attention as a simple and versatile manufacturing method. The electrospun nanofiber membrane has a unique structure and biological function similar to the extracellular matrix (ECM), and is considered an advanced wound dressing. They have significant potential in encapsulating and delivering active substances that promote wound healing. This article first discusses the common types of wound dressing, and then summarizes the development of electrospun fiber preparation technology. Finally, the polymers and common biologically active substances used in electrospinning wound dressings are summarized, and portable electrospinning equipment is also discussed. Additionally, future research needs are put forward.

Recrystallization of CsPbBr3 Nanoparticles in Fluoropolymer Nonwoven Mats for Down- and Up-Conversion of Light.

Inorganic halides perovskite CsPbX3 (X = Cl, Br, and I or mixed halide systems Cl/Br and Br/I) nanoparticles are efficient light-conversion objects that have attracted significant attention due to their broadband tunability over the entire visible spectral range of 410–700 nm and high quantum yield of up to 95%. Here, we demonstrate a new method of recrystallization of CsPbBr3 nanoparticles inside the electrospun fluoropolymer fibers. We have synthesized nonwoven tetrafluoroethylene mats embedding CsPbBr3 nanoparticles using inexpensive commercial precursors and syringe electrospinning equipment. The fabricated nonwoven mat samples demonstrated both down-conversion of UV light to 506 nm and up-conversion of IR femtosecond laser radiation to 513 nm green photoluminescence characterized by narrow emission line-widths of 35 nm. Nanoparticle formation inside nonwoven fibers was confirmed by TEM imaging and water stability tests controlled by fluorimetry measurements. The combination of enhanced optical properties of CsPbBr3 nanoparticles and mechanical stability and environmental robustness of highly deformable nonwoven fluoropolymer mats is appealing for flexible optoelectronic applications, while the industry-friendly fabrication method is attractive for commercial implementations.

Fabrication of nanofiber filters for electret air conditioning filter via a multi-needle electrospinning

Electrospinning technology is considered to be one of the efficient, convenient, and low-cost technologies for preparing nanofibers, which can be applied in various industries, including filtration, catalysis, and energy. Here, aiming at the performance requirements of the nanometer fiber filter membrane for filtering PM2.5, the preparation of the nanofiber filter membrane was realized based on multi-needle electrospinning equipment. Meanwhile, by adding silver nitrate to the spinning solution, a polyvinylidene fluoride antibacterial nanofiber filter layer with high filtration efficiency and low resistance was successfully prepared on the traditional air conditioning filter meshes. We found that four key factors affecting the filtration performance include ambient humidity, substrate meshes, voltage, and production rate. Among them, voltage and production rate are the key factors affecting the filtration performance. According to the development trend of multifunctional nanofiber membranes, the preparation of air conditioning filters with nanofibers as the main filter material was realized, producing air conditioning filter membranes with antibacterial and deodorizing functions. This article provides a reliable experimental basis and empirical reference for the preparation of nanofiber membranes based on multi-needle electrospinning technology.

2D and 3D electrospinning technologies for the fabrication of nanofibrous scaffolds for skin tissue engineering: A review.

This review provides insights into the current advancements in the field of electrospinning, focusing on its applications for skin tissue engineering. Furthermore, it reports the evolvement and present challenges of advanced skin substitute product development and explores the recent contributions in 2D and 3D scaffolding, focusing on natural, synthetic, and composite nanomaterials. In the past decades, nanotechnology has arisen as a fascinating discipline that has influenced every aspect of science, engineering, and medicine. Electrospinning is a versatile fabrication method that allows researchers to elicit and explore many of the current challenges faced by tissue engineering and regenerative medicine. In skin tissue engineering, electrospun nanofibers are particularly attractive due to their refined morphology, processing flexibility-that allows for the formation of unique materials and structures, and its extracellular matrix-like biomimetic architecture. These allow for electrospun nanofibers to promote improved re-epithelization and neo-tissue formation of wounds. Advancements in the use of portable electrospinning equipment and the employment of electrospinning for transdermal drug delivery and melanoma treatment are additionally explored. Present trends and issues are critically discussed based on recently published patents, clinical trials, and in vivo studies. This article is categorized under: Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Therapeutic Approaches and Drug Discovery > Emerging Technologies Implantable Materials and Surgical Technologies > Nanomaterials and Implants.

Electrospun aeolotropic electrically conductive neoteric janus nanostrips array functionalized by enhancive up-conversion luminescence and magnetism

Study on luminescent-electrically conductive-magnetic multifunctional nanomaterials has become one of the hotspots in the field of new materials owing to their unique properties and wide potential applications. In this work, [CoFe2O4/polymethylmethacrylate (PMMA)]@[polyaniline (PANI)/PMMA] coaxial nanobelt//[Y2O3:Yb3+, Er3+/PMMA] nanobelt structured Janus nanostrip and Janus nanostrips array (termed as [M@E]//UL JNA) are designed and prepared by peculiarly devised and manufactured electrospinning equipment. The distinct Janus nanostrip is composed of electrically conductive-magnetic difunctional [CoFe2O4/PMMA]@[PANI/PMMA] coaxial nanobelt and insulative up-conversion luminescence (UL) [Y2O3:Yb3+, Er3+/PMMA] nanobelt. Partition of three freestanding areas in Janus nanostrip is microscopically realized, and thus three functional substances are effectually limited to their own area to avert adverse mutual impact among different functions of aeolotropic conduction, magnetism and up-conversion luminescence. Neoteric Janus nanostrip is employed as building unit to ensure and endue the [M@E]//UL JNA with concurrent excellent polyfunctionality of aeolotropic conduction, magnetism and up-conversion luminescence. Formation mechanisms of peculiar-typed Janus nanostrip and their array are advanced, and novel techniques are established to construct exceptive Janus nanostrip and array. The flexible and processable [M@E]//UL JNA has potential applications in optical devices and conductive materials owing to the peculiar structure and performances. The neoteric technique provides a pathway to prepare other polyfunctional nanomaterials.

Synthesis and mechanical characterization of a non-woven nanofiber by the electrospinning technique

A non-woven nanofiber or polymeric cover is synthesized with nylon-6 as the base polymeric material. Different acid relationships (formic/acetic) were tested in the electrospinning equipment, until defining by macroscopic observations and SEM Scanning Electron Microscopy analysis the adequate acid ratio 3:2 and the average diameter of the nanofibers in 350nm, defining the parameters to operate the electrospinning. According to ASTM D 882 standard, the Tensile Strength was calculated for stresses applied horizontally and vertically to the direction of the nanofibers. With the standards ASTM D 7490 and ASTM G-15 the wettability was determined by measuring the contact angle, finding that it has hydrophilic properties with high wettability, adhesiveness and surface energy. Nanostructured polymer covers can be used for biological isolation in health care areas, as a protective barrier to control the spread of infections.

A hybrid platform for three-dimensional printing of bone scaffold by combining thermal-extrusion and electrospinning methods

The aim of this study is to develop a hybrid 3D printing platform integrating thermal-extrusion and electrospinning methods to fabricate bone scaffolds. The scaffolds made by mPEG–PCL–mPEG/HA biocomposite and their surface were enhanced by adding an electrospun fibre layer which improved adhesion and viability of osteoblastic cells. The scaffolds were evaluated by mechanical testing; biochemical analyses, SEM observation and their capabilities for supporting growth and adhesion of osteoblastic cells were also assessed in vitro. The 3D printing platform can manufacture the controllable and complicated shapes of bone scaffolds by controlling the thermal-extrusion and electrospinning equipment. It also can control the pore size, porosity and pore interconnectivity, and stack the scaffold structure by using different materials and different ways. Analyses showed that the bone scaffolds have a good mechanical strength and the scaffolds are suitable to support growth of MC3T3-E1 osteoblastic cells; and the electrospun fibres may increase the surface area of the fabricated scaffolds for the future application in modulating osteoblast response. Thus, it is feasible to produce bone tissue engineering scaffolds integrating thermal-extrusion and electrospinning techniques using our 3D printing platform.