Ultrafine Fibers Research Articles

An Overview of the Electrospinning of Polymeric Nanofibers for Biomedical Applications Related to Drug Delivery

Electrospinning is a prominent technique for micro/nanofiber production and has received significant attention in the 21st century. It enables the production of ultrafine fibers using a variety of polymers, including synthetic, natural, and hybrid materials. Electrospun nanofibers (NFs) possess unique properties such as a high surface‐to‐volume ratio, tunable pore structures, and customizable composition, making them highly desirable in various fields such as biomedical science, textiles, sensors, filters, energy, and packaging. Herein, particular attention will be given to the application of NFs in biomedical fields. The use of NFs for the delivery of drugs, growth factors, proteins, nanoparticles, etc., holds significant promise in the field of biomedical science. To combine these compounds with NFs, various electrospinning techniques have been developed with outstanding improvements, and based on the requirements of the application type, different electrospinning processes are favored. In this review, the most common drug loading methods into NFs, generally used synthetic/natural polymers for NF production, and their application in drug delivery systems, tissue engineering, and wound dressing will be mentioned. Finally, challenges and future perspectives for above mentioned biomedical applications are discussed.

Intrinsic conducting strain sensors with negative resistive effects for extreme environments applications

The sensors used in extreme environments has broad application prospects. Herein, the ultra-fine stainless-steel fibers are knitted into a stainless-steel mesh (SSM) by warp knitting. Through the simple plate coating method, the SSM@silicone composite strain sensors are prepared. The sensor shows obvious negative resistance effects, meanwhile, it has the advantages of high sensitivity (GF = 14.9), wide detection range (30 %), good repeatability, and can be used at 300 ℃ and −20 ℃. It is anticipated to be applied on robots that perform tasks in extreme temperature environments.

Gelatin nanofibers with black elderberry, Au nanoparticles and SnO2 as intelligent packaging layer used for monitoring freshness of Hake fish

The electrospun gelatin nanofibers containing black elderberry (BE) extract, Au nanoparticles (AuNPs) and SnO2 were fabricated as intelligent packaging layer for Hake fish (Merluccius merluccius) fillets. Image analysis confirmed the formation of continuous ultrafine fibers. Differences between nanofibers were evaluated in terms of thermal stability, and chemical composition during storage. Fourier transform infrared spectrums indicated strong bonding interactions between gelatin and other compounds. Thermal analysis results showed that the addition of AuNPs contributed to the thermal stabilization of the gelatin chain. L, a, and b values of nanofibers were also measured. A rapid color change occurred after exposure to volatiles with the highest difference in L (52.29 %) of the sample containing gelatin, BE, SnO2 and AuNPs (p < 0.05). This study showed that the absorption of volatiles on nanofibers can be detected from color changes of nanofibers. The outcomes of this study can be applied for intelligent packaging layer in seafood products.

The history, interests and future of polyphenylene sulfide: A bibliometric analysis

Polyphenylene sulfide (PPS) with unique performance advantages and development potential is widely used in electronics, aerospace, environmental protection, automobile, machinery, textile, chemical, pharmacy, environmental protection and other industries. The researches on PPS material are constantly advancing and improving in both quantity and quality. To clarify the progress and status, and to explore current focus and development trend of PPS at a global level, the bibliometric analysis was used based on Web of Science Core Collection database. 1118 papers were retrieved, and countries or regions, institutions, journals, authors, research areas, author keywords, and highly cited articles were discussed in detail. The results of bibliometric analysis show that China was the dominant country in terms of contributions of paper output, followed by the USA, South Korea, Japan, India, and Germany. Germany and China both were the most active partner which worked with other high productive countries. “Polymer science” was the most attractive research area with 451 papers involved in. “Journal of Applied Polymer Science” was the most comprehensive source of PPS material publications and with the highest h-index. The author keywords “mechanical property”, “behavior”, “composite”, “morphology”, “kinetics”, “friction”, “tribological property” and “crystallization” reflected a high level attention and hot topics for PPS. Based on the results of bibliometric analysis, the research progress and achievements of preparation, performance improvement and application field expansion in recent years were summarized and explained. To achieve more comprehensive performance and to be suitable for more special applications in various fields, the enhancement and toughening of PPS, the modification by blending or alloying with other polymers or other reinforcing materials, the production of PPS ultrafine fiber and PPS membrane were shownas the research emphasis.

Electrospun Fibers Loaded with Probiotics: Fundamentals, Characterization, and Applications.

Increasing demand for safe, efficient, and eco-friendly solutions for pharmaceutical and food industries has led researchers to explore new approaches to bacterial storage. Several advantages make electrospinning (ES) a promising technique for food systems, including simple manufacturing equipment, a relatively low spinning cost, a wide variety of spinnable materials, and a mild process that is easily controlled, which allows continuous fabrication of ultrafine polymeric fibers at submicron or nanoscales without high temperatures or high pressures. This review briefly describes recent advances in the development of electrospun fibers for loading probiotics (PRB) by focusing on ES technology, its efficiency for loading PRB into fibers (viability, digestive stability, growth rate, release, thermal stability, and interactions of fibers with PRB), and the application of PRB-loaded fibers as active packaging (spoilage/microbial control, antioxidant effect, shelf life). Based on the literature reviewed, the incorporation of PRB into electrospun fibers is both feasible and functional. However, several studies have been limited to proof-of-principle experiments and the use of model biological products. It is necessary to conduct further research to establish the industrial applicability of PRB-loaded fibers, particularly in the fields of food and medicine.

Fabrication of cassava (Manihot esculenta Crantz) starch‐based ultrafine fibers: Investigation of fundamental and antimicrobial properties

AbstractMicro/nano‐based fibrous membranes loaded with antibacterial agents have been widely studied in the medical field. In this research, we describe the development of a new environmentally friendly medical dressing based on centrifugally spun cassava starch‐based ultrafine fibers loaded with nanosilver (Ag). For this purpose, the spinnability of amylopectin‐rich native cassava starch in a centrifugal spinning system was investigated. Polyvinyl alcohol (PVA) was applied to improve the water stability and mechanical properties of the starch‐based fibers, and the water stability of the fibers was further improved by posttreatment with formic acid. The morphology, structure, thermal, and tensile properties were studied. The results indicated that the native cassava starch showed excellent spinnability in the centrifugal spinning system. The tensile strength and water stability of the obtained fibrous membranes were improved by adding PVA and further improved after the posttreatment. The antibacterial properties of fibers loaded with Ag were evaluated through a bacteriostatic zone test, and the results showed that the fibers presented good antibacterial properties against Escherichia coli. Therefore, the obtained fibers have great potential for application in the medical dressing field.

High-strength electrospun ceramic ultrafine fibers based on in-situ polymer-derived technology

Improving the mechanical strength of electrospun ceramic ultrafine fibers (UFs) is crucial for both structural and functional applications. Herein, we report a facile strategy of in-situ embedding ZrO2 nanocrystals (NCs) in polycarbosilane-derived silicon carbide (SiC) UFs. The morphology, chemical composition, mechanical properties, and cross-section morphologies of single UFs are characterized to investigate the effects of introducing ZrO2 NCs. Notably, a single ZrO2 NCs/SiC UF with an average ZrO2 NCs size of 4.5 ± 1.3 nm possesses optimum mechanical performance, it exhibits about 371.3% increase in tensile strength and 6 times improvement in fracture energy when compared with SiC UFs. The uniformly distributed ZrO2 NCs increase the fiber density that reduce the internal defects, which improve the strength of SiC UF. The enhanced fracture energy can be attributed to the efficient fracture energy dissipation mechanism related to the NCs size. This work provides a viable strategy for designing ceramic fibers with enhanced mechanical properties.

PRODUCTION AND CHARACTERIZATION OF PHB, PHBV ELECTROSPUN FIBERS AND THEIR BLENDS

Polhydroxbutyrates (PHBs) are well-known bio-based and biodegradable bacterial polyesters. In this study, the effects of polymer type, solution concentration and feeding rate on the electrospinnability of Poly(3-hydroxbutyrate) (PHB) and Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) PHBV nanofibers were investigated. First, PHB, PHBV and PHB/PHBV solutions with different polymer concentrations ranging between 5-11% wt. were prepared and characterized in terms of viscosity. Afterwards, electrospinning was performed and ultrafine fibers were produced. The surface morphology and the fiber diameters of the samples were investigated by scanning electron microscopy (SEM) analyses. Pore sizes of the samples were also calculated. In order to understand the wettability of the samples, contact angle measurements were conducted. The thermal properties and the crystallinity of the samples were investigated differential scanning calorimetry (DSC) analyses. The solution viscosities increased dramatically above %9 wt. of polymer concentration. SEM images revealed that decreasing feeding rate and increasing solution concentration resulted in fewer bead formation. On the other hand, fibers with diameters from 1.2 to 5.4 μm were produced with the increasing solution concentration and increasing voltage. All samples showed contact angle values above 90° indicating that they are hydrophobic. The PHB/PHBV blend surface showed the highest contact angle. DSC analyses showed that PHBV surface had significantly lower crystallization degree than PHB surface produced at the same concentration. It can be concluded that PHB fibers can be successfully produced by electrospinning.

The Influence of Technological Factors and Polar Molecules on the Structure of Fibrillar Matrices Based on Ultrafine Poly-3-hydroxybutyrate Fibers Obtained via Electrospinning

The article examines the regularities of structure formation of ultrafine fibers based on poly-3-hydroxybutyrat under the influence of technological (electrical conductivity, viscosity), molecular (molecular weight), and external factors (low-molecular and nanodispersed substances of different chemical natures). Systems with polar substances are characterized by the presence of intermolecular interactions and the formation of a more perfect crystalline fiber structure. Changes in technological and molecular characteristics affect the fiber formation process, resulting in alterations in the morphology of the nonwoven fabric, fiber geometry, and supramolecular fiber structure. Polymer molecular weight, electrical conductivity, and solution viscosity influence fiber formation and fiber diameter. The fiber structure is heterogeneous, consisting of both crystalline and non-equilibrium amorphous phases. This article shows that with an increase in the molecular weight and concentration of the polymer, the diameter of the fiber increases. At the same time, the increase in the productivity of the electrospinning process does not affect the fiber geometry. The chemical structure of the solvent and the concentration of polar substances play a decisive role in the formation of fibers of even geometry. As the polarity of the solvent increases, the intermolecular interaction with the polar groups of poly-3-hydroxybutyrate increases. As a result of this interaction, the crystallites are improved, and the amorphous phase of the polymer is compacted. The action of polar molecules on the polymer is similar to the action of polar nanoparticles. They increase crystallinity via a nucleation mechanism. This is significant in the development of matrix-fibrillar systems for drug delivery, bioactive substances, antiseptics, tissue engineering constructs, tissue engineering scaffolds, artificial biodegradable implants, sorbents, and other applications.

Direct Synthesis of Elastic and Stretchable Hierarchical Structured Fiber and Graphene-Based Sponges for Noise Reduction.

Noise pollution, as one of the three major pollutants in the world, has become a great burden on people's health and the global economy. Most present noise absorbers suffer large weight and inevitable compromise between good low-frequency (usually <1000 Hz) and high-frequency (typically >1000 Hz) noise reduction performance. This study presents a scalable strategy to directly synthesize ultrafine fiber sponges with ultrathin graphene-based vibrators by the synchronous occurrence of humidity-assisted electrospinning and electrospraying. The unique physical entanglements between reduced graphene oxide (rGO) nanosheets and ultrafine fibers endow hierarchical vibration structured fiber sponges (VSFSs) with excellent mechanical properties, which could withstand large shear strain (60%) and tensile stress (6000 times its weight) without damage and almost have no plastic deformation after 1000 compressions. Attribute to the vibration effect of ultrathin graphene-based vibrators and the viscous friction effect of porous fiber networks, the VSFSs achieve both good low-frequency (absorption coefficient of 0.98 in 680 Hz) and high-frequency sound absorption (absorption coefficients above 0.8 in 2000-6300 Hz) simultaneously. Furthermore, the noise reduction coefficient (NRC) of lightweight VSFSs (thickness of 30 mm) reaches 0.63, which could reduce high decibel noise by 24.4 dB, providing potential solutions for developing ideal noise-absorbing materials.

Polylactide/cellulose pulp composite paper with laminate structure via polylactide ultrafine fiber for eco-friendly straw

Paper straws with environmental friendliness have been widely used to replace plastic straws, but their poor mechanical properties and uncontrollable deformation bring an unsatisfactory experience for users. Herein, we developed a polylactic acid/cellulose fiber (PLA/CF) ultrafine-fiber paper with a sandwich‐like structure via wet papermaking and laminated hot pressing, employing PLA ultrafine fiber and CF as raw materials. The PLA/CF ultrafine fiber paper has remarkable mechanical properties due to the tangling of the fibers and the strong hydrogen bonding that occurs between the PLA and CF during hot pressing. The test results demonstrate that the tensile strength of PLA/CFs ultrafine fiber paper can reach 60.32 N/cm, and it still retains great wet strength (27 N/cm) and stiffness (117.7 mN·cm) after long-time service in various clod and hot liquids. Besides, PLA/CF ultrafine fiber paper also displays high biodegradability, with a degradation rate of 70% after being buried in soil for 120 days. We believe that PLA/CF ultra-fine fiber paper with excellent comprehensive performance can be expected to completely replace plastic straws.

Preparation of capsaicin-loaded ultrafine fiber film and its application in the treatment of oral ulcers in rats

A drug-loaded diaphragm is an easy-to-use and effective drug delivery system that is often used to treat mouth ulcers. In this study, an ultrafine fiber film loaded with capsaicin was successfully prepared using the electrospinning technology. poly-l-lactic acid and gelatin were selected as the matrix materials to form the composite fiber, and trifluoroethanol was used as a co-solvent for poly-l-lactic acid, gelatin and capsaicin to prepare the spinning solution, which was simple to fabricate. The prepared fiber films were characterized based on their microscopic morphology and tested to derive their mechanical properties. Thereafter, the capsaicin release behavior of the film was investigated. In vitro experiments revealed certain anti-inflammatory and antibacterial abilities while animal experiments revealed that the capsaicin-loaded ultrafine fiber film could promote the healing of oral ulcers in rats. Healing of the tongue tissue in rats administered 10% capsaicin-loaded fiber film was found to be better than that in rats administered the commercial dexamethasone patch. Overall, this development strategy may prove to be promising for the development of oral ulcer patch formulations.

Mesoscopic Simulation of Centrifugal Melt Electrospinning of PPESK

AbstractPoly(aryl ether sulfone ketone) (PPESK) is an engineering plastic with high strength, good heat resistance, insulation, and chemical corrosion resistance. The properties of PPESK fiber prepared by centrifugal melt electrospinning can be improved, and the method is efficient and environmentally friendly. This article employs a systematic analysis to investigate the impact of process parameters on the jet formation process, jet motion, fiber diameter, fiber yield, and changes in molecular chain orientation of PPESK. The analysis uses dissipative particle dynamics simulation to reveal that PPESK fibers can attain a certain degree of refinement, and fiber yield can be increased with an appropriate increase in rotational speed, temperature, and electric field force. Moreover, for PPESK with different chain lengths, longer molecular chains impede the untwisting of the molecular chains within the fiber, weakening the fiber orientation, increasing fiber diameter, and resulting in a slower fiber yield increase. These simulation results provide theoretical guidance for preparing PPESK ultrafine fibers with the required performance, shortening the exploration process of actual spinning, and saving time and labor.

A Straightforward Method to Produce Multi-Nanodrug Delivery Systems for Transdermal/Tympanic Patches Using Electrospinning and Electrospray.

The delivery of drugs through the skin barrier at a predetermined rate is the aim of transdermal drug delivery systems (TDDSs). However, so far, TDDS has not fully attained its potential as an alternative to hypodermic injections and oral delivery. In this study, we presented a proof of concept of a dual drug-loaded patch made of nanoparticles (NPs) and ultrafine fibers fabricated by using one equipment, i.e., the electrospinning apparatus. Such NP/fiber systems can be useful to release drugs locally through the skin and the tympanic membrane. Briefly, dexamethasone (DEX)-loaded poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) fiber meshes were decorated with rhodamine (RHO)-loaded poly(lactic-co-glycolic acid) (PLGA) NPs, with RHO representing as a second drug model. By properly tuning the working parameters of electrospinning, DEX-loaded PHBHV fibers (i.e., by electrospinning mode) and RHO-loaded PLGA NPs (i.e., by electrospray mode) were successfully prepared and straightforwardly assembled to form a TDDS patch, which was characterized via Fourier transform infrared spectroscopy and dynamometry. The patch was then tested in vitro using human dermal fibroblasts (HDFs). The incorporation of DEX significantly reduced the fiber mesh stiffness. In vitro tests showed that HDFs were viable for 8 days in contact with drug-loaded samples, and significant signs of cytotoxicity were not highlighted. Finally, thanks to a beaded structure of the fibers, a controlled release of DEX from the electrospun patch was obtained over 4 weeks, which may accomplish the therapeutic objective of a local, sustained and prolonged anti-inflammatory action of a TDDS, as is requested in chronic inflammatory conditions, and other pathological conditions, such as in sudden sensorineural hearing loss treatment.

Chlorinated-based bioceramics incorporated in polycaprolactone membranes.

The development of bioactive membranes with bone repair properties is great interest in the field of tissue engineering. In this study, we aimed to fabricate and characterize a composite membrane composed of sol-gel synthesized bioceramics and electrospun polycaprolactone (PCL) fibers for bone tissue regeneration applications. The bioceramics were prepared using the sol-gel method with nitrate (N) and chloride (CL) as precursors. PCL and bioceramic solutions were electrospun to obtain ultrafine fiber mats. Raman spectroscopy, x-ray diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) were used to characterize the materials. The results showed that both chlorinated and non-chlorinated bioceramics contained NBOs (non-bridge bonds) and crystallized the α-wollastonite phase, with the chlorinated version doing so at lower temperatures. In vitro tests were performed to evaluate cytotoxicity, cell adhesion, and mineralized matrix formation on the membranes. The composite membranes showed improved cell viability and promoted mineralization nodules formation. This study presents a promising approach for the development of bioactive membranes for bone tissue engineering, with potential applications in bone regeneration therapies.

Processability of Thermoelectric Ultrafine Fibers via Electrospinning for Wearable Electronics.

Polymer-based thermoelectric generators hold great appeal in the realm of wearable electronics as they enable the utilization of body heat for power generation. Fibers produced from conducting polymers for use in thermoelectric generators have high porosity and good flexibility, providing comfort-based performance advantages over thin films for wearable electronics. Some fiber processing techniques have been explored to produce textile-based thermoelectric generators; however, they fail to approach the conductivities of polymeric thin films. Ultrafine fibers solution processed through electrospinning yield fiber diameters on the nanoscale, allowing for high surface area to volume ratios and thus low thermal conductivity; however, a number of processing challenges in electrospinning conducting polymers limit the success of preparing high performing thermoelectric textiles. In this work, the specific processing challenges inherent to electrospinning conducting polymers are addressed for both n- and p-type materials. For the p-type polymer, 63 wt % PEDOT:PSS fibers are fabricated through solution formulation improvements yielding a conductivity of 3 S/cm and a power factor of 0.1 μW/mK2. The first of their kind n-type poly(NiETT)/PVA electrospun fibers were created yielding a conductivity of 0.11 S/cm and a power factor of 0.0036 μW/mK2. These nonwoven ultrafine fiber mats show progress toward achieving textile-based thermoelectric materials with equivalent performance of comparable polymeric thin films. This work shows the feasibility of creating ultrafine fibers for use in thermoelectric generators through electrospinning including the first demonstration of poly(NiETT)/PVA fibers.

Chemical Composition Analysis of Atropa belladonna Grown in Iran and Evaluation of Antibacterial Properties of Extract-loaded Nanofibers.

In the present work, the chemical composition of extract fractions of the Atropa belladonna plant growing in the north of Iran was investigated by HPTLC, HPLC, and GC-MS. Based on HPLC results, atropine, and scopolamine were found to be higher in the fruit and leaf extracts than in other parts of the plant. The comparative GC-MS analysis showed that diacetone alcohol, mesityl oxide, palmitic acid, and linoleic acid were the major bioactive components in the root, stem, leaf, and fruit extracts, respectively. Leaf extract showed the best antioxidant activity in the DPPH test. The antibacterial activity of fractional extracts was determined against Pseudomonas aeruginosa using the MIC method, and the fruit and leaf extracts exhibited the best antibacterial activities. The leaf extract was embedded into nanofibers by electrospinning technique, and its antibacterial activity was determined against Pseudomonas aeruginosa. The morphology and mechanical properties of the nanofibers were studied with SEM, contact angle, and tensile analysis, showing ultrafine fibers with uniform morphology.

Investigation of Safety and Usefulness of Hypoirritant Nonwoven Mask Using Ultrafine Fiber

Investigation of Safety and Usefulness of Hypoirritant Nonwoven Mask Using Ultrafine Fiber

A nonenzymic microfiber optic-biosensor modified phenylboric acid for sensitively and specifically detecting low glucose concentration

A microfiber interferometer coated with sensitive films formed by amide bond between 3-Carboxy-4-fluorophenylboronic acid (FPBA) and polydopamine (PDA) for the detection of trace glucose concentration is designed and demonstrated. Due to a huge evanescent field, this microfiber interferometer has a very sensitive response to the refractive index (RI) of the surrounding environment, which has excellent sensing performance including RI sensitivity response of 1825.83 nm/RIU and low temperature response of −0.04 nm/°C. Due to the good film-forming performance of PDA, whose the amino group coupled with the carboxyl molecule on FPBA to form an amide bond, PDA/FPBA can be attached to the microfiber interferometer for detecting different concentrations of glucose. The concentration range of glucose detection is 0.1–20 mM with a sensitivity of 1.71 nm/mM and a limit of detection of 12.6 ppm. Finally, the sensor is tested in actual samples of human urine to detect different concentrations of glucose and proved to be responsive and reproducible in urine. We can estimate the concentration of glucose in urine by wavelength shift. The sensor has the advantages of simple manufacture, low cost, high sensitivity, and specific recognition glucose in urine. In addition, the success of this sensor shows that the combination of ultrafine fiber and organic chemical materials has broad prospects in the field of optical detection.

Synthesis of a polyester with a liquid crystalline silsesquioxane-contained backbone Chain

A one-pot multistep growth melt procedure utilizing multistep feeding has been developed to enable the synthesis of thermoplastic polymers based on 4-hydroxybenzoic acid (HBA) and 6-hydroxy-2-naphthoic acid (HNA)with greater numbers of alternating units in their backbone chains. The decreased melting point (Tm) and glass transition temperature (Tg) indicated that the multistep feeding procedure helped to enhance the flexibility of the backbone chain due to the increasing number of alternating blocks, due to a reduction in the stacking between different main-chains, thus enabling the formation of liquid crystalline polyester (LCP) fibers with oriented structures. The covalent incorporation of rigid cage-like silsesquioxane groups led to a significant reduction of the melting point, resulting from the inevitable transformation of the original symmetrical backbone structure to a less ordered structure, due to the steric effect and hybrid feature of silsesquioxane. The presentation of silsesquioxane groups also enhanced the aggregation of ultrafine fibers with well-aligned orientation in the molten state and produce stronger fiber bundles.