Sequential Electrospinning Research Articles

A porous Janus nanofiber membrane with unidirectional water vapor transport for efficient dust personal protection

The generation of coal dust affects all aspects of coal mining, posing a serious threat to miner’s health. However, developing a novel respirator material with high respiratory efficiency and low resistance poses a significant challenge. Additionally, traditional masks can cause water vapor from exhaled breath to condense into minuscule droplets that adhere to the inside of the mask, reducing comfort. In this study, a porous Janus nanofiber membrane was successfully prepared using sequential electrospinning technology combined with post-treatment techniques. Due to its unique porous structure and double-sided anisotropy, the Janus nanofiber membrane achieves high filtration efficiency and low air resistance simultaneously. Under a high-intensity respiration rate of 85 L/min, the Janus nanofiber membrane maintains a filtration efficiency of 99.98 % and a pressure drop of 134.7 Pa. Moreover, the Janus nanofiber membrane can effectively transport water vapor from exhaled breath to the external environment. The external hydrophobic membrane effectively intercepts water mist from the air. The Janus nanofiber membrane water vapor transmittance can reach 2633.863 cm3/m2·d·Pa. The contact angle of the hydrophobic side of the nanofiber membrane reached 145°, while the contact angle of the hydrophilic side reached 0° after 3 s of water droplet exposure. These features greatly improve user comfort. Taken together, our findings demonstrate the promising potential of the newly developed Janus nanofiber membrane for individual protection.

Janus Nanofibrous Patch with In Situ Grown Superlubricated Skin for Soft Tissue Repair with Inhibited Postoperative Adhesion.

The patch with a superlubricated surface shows great potential for the prevention of postoperative adhesion during soft tissue repair. However, the existing patches suffer from the destruction of topography during superlubrication coating and lack of pro-healing capability. Herein, we demonstrate a facile and versatile strategy to develop a Janus nanofibrous patch (J-NFP) with antiadhesion and reactive oxygen species (ROS) scavenging functions. Specifically, sequential electrospinning is performed with initiators and CeO2 nanoparticles (CeNPs) embedded on the different sides, followed by subsurface-initiated atom transfer radical polymerization for grafting zwitterionic polymer brushes, introducing superlubricated skin on the surface of single nanofibers. The poly(sulfobetaine methacrylate) brush-grafted patch retains fibrous topography and shows a coefficient of friction of around 0.12, which is reduced by 77% compared with the pristine fibrous patch. Additionally, a significant reduction in protein, platelet, bacteria, and cell adhesion is observed. More importantly, the CeNPs-embedded patch enables ROS scavenging as well as inhibits pro-inflammatory cytokine secretion and promotes anti-inflammatory cytokine levels. Furthermore, the J-NFP can inhibit tissue adhesion and promote repair of both rat skin wounds and intrauterine injuries. The present strategy for developing the Janus patch exhibits enormous prospects for facilitating soft tissue repair.

High-yield fabrication of monodisperse multilayer nanofibrous microparticles for advanced oral drug delivery applications

Recent advances in the use of nano- and microparticles in drug delivery, cell therapy, and tissue engineering have led to increasing attention towards nanostructured microparticulate formulations for maximum benefit from both nano- and micron sized features. Scalable manufacturing of monodisperse nanostructured microparticles with tunable size, shape, content, and release rate remains a big challenge. Current technology, mainly comprises complex multi-step chemical procedures with limited control over these aspects. Here, we demonstrate a novel technique for high-yield fabrication of monodisperse monolayer and multilayer nanofibrous microparticles (MoNami and MuNaMi respectively). The fabrication procedure includes sequential electrospinning followed by micro-cutting at room temperature and transfer of particles for collection. The big advantage of the introduced technique is the potential to apply several polymer-drug combinations forming multilayer microparticles enjoying extracellular matrix (ECM)-mimicking architecture with tunable release profile. We demonstrate the fabrication and study the factors affecting the final three-dimensional structure. A model drug is encapsulated into a three-layer sheet (PLGA-pullulan-PLGA), and we demonstrate how the release profile changes from burst to sustain by simply cutting particles out of the electrospun sheet. We believe our fabrication method offers a unique and facile platform for realizing advanced microparticles for oral drug delivery applications.

Electrospinning janus membranes for on‐demand oil/water collection and emulsion separation

AbstractOily water pollution has become one of the most serious water environment issue in worldwide. Membrane that can effectively and efficiently remove different oil pollutions from the complex water environment is still urgently needed. Herein, a Janus membrane with opposite wettability that can separate heavy oil–water and light oil–water mixtures on demand was prepared by using a simple sequential electrospinning and chemical crosslinking method. The membrane could remove oil or water under gravity with a high oil/water flux and excellent separation efficiency. Moreover, the membrane could separate different kinds of oil‐in‐water emulsions under gravity with a high flux of 1184 L m−2 h−1 and a tiny flux loss of 4.4% after a 10‐cycle separation. Owing to its excellent anti‐pollution properties the flux recovery rate of the membrane was still higher than 80% after 150 min of emulsion separation. Additionally, the membrane also displayed the ability to transport liquid unidirectionally, giving whom the capabilities to collect oil underwater or water underoil. This research provides a novel and simple method for producing membranes for a variety of separation applications.

Electrospun membrane of PLA/calendula with improved UV protection and stable filtration performance

The “dual carbon” strategy and the severe air pollution problem have spurred the development of environmentally friendly functional filters. However, the performance stability of degradable polymers under ultraviolet (UV) irradiation needs to be explored and addressed. Loading natural small molecules onto electrospun fibers can enhance their functionality and sustainability. This study explores the use of calendula extract to protect polylactic acid electrospun fibers from UV degradation and provide antibacterial properties. A double-layer filter was created using straightforward sequential electrospinning. Only one-third of the fiber membrane's thickness contains drugs, resulting in an 88 % inhibition rate against Staphylococcus aureus. Its UV protection capability has been significantly enhanced. The calendula filters exhibited a tensile strength loss rate of only 23 %, compared to 30 % for the unmodified filters. Furthermore, the calendula extract altered the morphology and porous structure of the fibers, leading to an enhancement in the stable filtration efficiency of the membrane. It maintains a filtration efficiency of over 99 % at a flow rate of 32–85 L/min. This study has enhanced the stable filtration capacity of biomass filters and showcased their potential for UV protection and antibacterial applications.

Structural design and mechanical analysis of small-caliber bilayer vascular prostheses

This research comprehensively addresses the influence of structural properties and polymer type on the mechanical performance of bilayer vascular grafts. The grafts consist of inner layers with randomly distributed polycaprolactone(PCL)/polylactic acid(PLA) or poly(l-lactide-co-caprolactone)(PLCL) fibers and an outer layer with radially oriented PLCL fibers, manufactured through a sequential electrospinning process. Highlighted results indicate that tubular scaffolds possess an inner layer ranging in thickness from 62 to 94 µm, while their outer layers vary in thickness from 180 to 296 µm. In addition, radially oriented fibers enhance tensile strength in radial direction (9–11 MPa), while depending on polymer composition and wall thickness proportions of individual layers, tensile strength values change between 2.7 and 7.7 MPa in longitudinal direction. Scaffolds with elastic PCL or PLCL inner layers display higher compliance values (above 1%/mmHg × 10−2).

Fabrication and characterization of a multi-functional GBR membrane of gelatin-chitosan for osteogenesis and angiogenesis

Guided bone regeneration (GBR) membranes are widely used to treat bone defects. In this study, sequential electrospinning and electrospraying techniques were used to prepare a dual-layer GBR membrane composed of gelatin (Gel) and chitosan (CS) containing simvastatin (Sim)-loaded poly(lactic-co-glycolic acid) (PLGA) microspheres (Sim@PLGA/Gel-CS). As a GBR membrane, Sim@PLGA/Gel-CS could act as a barrier to prevent soft tissue from occupying regions of bone tissue. Furthermore, compared with traditional GBR membranes, Sim@PLGA/Gel-CS played an active role on stimulating osteogenesis and angiogenesis. Determination of the physical, chemical, and biological properties of Sim@PLGA/Gel-CS membranes revealed uniform sizes of the nanofibers and microspheres and appropriate morphologies. Fourier-transform infrared spectroscopy was used to characterize the interactions between Sim@PLGA/Gel-CS molecules and the increase in the number of amide groups in crosslinked membranes. The thermal stability and tensile strength of the membranes increased after N-(3-dimethylaminopropyl)-N9- ethylcarbodiimide/N-hydroxysuccinimide crosslinking. The increased fiber density of the barrier layer decreased fibroblast migration compared with that in the osteogenic layer. Osteogenic function was indicated by the increased alkaline phosphatase activity, calcium deposition, and neovascularization. In conclusion, the multifunctional effects of Sim@PLGA/Gel-CS on the barrier and bone microenvironment were achieved via its dual-layer structure and simvastatin coating. Sim@PLGA/Gel-CS has potential applications in bone tissue regeneration.

Zein Multilayer Electrospun Nanofibers Contain Essential Oil: Release Kinetic, Functional Effectiveness, and Application to Fruit Preservation.

In this study, sequential electrospinning was employed to produce a multilayer film consisting of zein nanofibers (Z) and Zataria multiflora essential oil (ZMEO) with different layers. The layers include: Z (without ZMEO), Z1 (one layer of Z + ZMEO), Z3 (three layers of Z + ZMEO), and Z5 (five layers of Z + ZMEO). Then, the effect of this antimicrobial packaging was investigated in relation to increasing the shelf life of strawberries at 4 °C for 12 days. The scanning electron microscopy (SEM) images of the fibers demonstrated a uniform and smooth structure without any beads. The use of Fourier transform infrared (FTIR) and Differential scanning calorimetry (DSC) showed that ZMEO was physically encapsulated into multilayer Z, resulting in an enhancement in thermal stability. The multilayer film showed a sustained release pattern of the encapsulated ZMEO for Z3, lasting for 90 h, and Z5, lasting for 180 h. This was in contrast to the rapid release within 50 h observed with Z film. The release kinetics for Z5 showed a good correlation with both the Higuchi and Korsmeyer-Peppas models, while for Z1 and Z3 films, Fickian diffusion was identified as the underlying mechanism. The findings of this study indicated that the multilayer film released ZMEO through a combination of diffusion and polymeric erosion. During a 12-day period of cold storage, strawberries that were treated with Z5 showed significant preservation of their anthocyanin (32.99%), antioxidant activity (25.04%), weight loss (24.46%), titratable acidity (11.47%), firmness (29.67%), and color (10.17%) compared to the control sample. The findings indicated that the sequential electrospinning technique used to create the multilayer nanofibrous film could be used in various fields, such as bioactive encapsulation, controlled release, antimicrobial packaging, and food preservation.

Trilayer composite scaffold for urethral reconstruction:in vitroevaluation of mechanical, biological, and angiogenic properties.

Regeneration of damaged urethral tissue remains a major challenge in the field of lower urinary tract reconstruction. To address this issue, various synthetic and natural biodegradable biomaterials are currently being explored for the fabrication of scaffolds that promote urethral regeneration and healing. In this study, we present an approach to fabricate a trilayer hybrid scaffold comprising a central layer of poly(lactic acid) (PLA) between two layers of chitosan. The chitosan/PLA/chitosan (CPC) scaffolds were fabricated by a sequential electrospinning process and their properties were evaluated for their suitability for urethral tissue engineering. The physical and biological properties of the CPC scaffolds were evaluated in comparison to electrospun PLA scaffolds and acellular dermis (Alloderm) as controls for a synthetic and a natural scaffold, respectively. Compared to the controls, the CPC scaffolds exhibited higher elastic modulus and ultimate tensile strength, while maintaining extensibility and suture retention strength appropriate for clinical use. The CPC scaffolds displayed significant hydrophilicity, which was associated with a higher water absorption capacity of the chitosan nanofibres. The degradation products of the CPC scaffolds did not exhibit cytotoxicity and promoted wound closure by fibroblastsin vitro. In addition, CPC scaffolds showed increased growth of smooth muscle cells, an essential component for functional regeneration of urethral tissue. Furthermore, in a chicken embryo-based assay, CPC scaffolds demonstrated significantly higher angiogenic potential, indicating their ability to promote vascularisation, a crucial aspect for successful urethral reconstruction. Overall, these results suggest that CPC hybrid scaffolds containing both natural and synthetic components offer significant advantages over conventional acellular or synthetic materials alone. CPC scaffolds show promise as potential candidates for further research into the reconstruction of the urethrain vivo.

Miniaturization of an enclosed electrospinning process to enhance reproducibility in the fabrication of rapidly dissolving cell-based biosensors.

There is broad interest in producing electrospun films embedded with biological materials. It is well known that electrospinning requires careful control of the process conditions, especially the environmental conditions such as relative humidity (RH). Given that commercial electrospinning systems are expensive (>$10,000) and are typically too large to be used in standard biological safety cabinets (BSC), we designed and built a miniaturized electrospinning box (E-Box) that will fit inside a BSC, and the RH can be easily controlled using simple instrumentation (gas cylinder, regulator, needle valve, rotameter). It uses an inexpensive computerized numerical control machine to control the spinneret positioning and collector rotational speed-all the parts for the device (except the syringe pump and voltage supply) can be purchased for approximately $1000. We demonstrate the usefulness of our design in optimizing the production of Escherichia coli-embedded pullulan-trehalose films to be used as rapidly dissolving biosensors for environmental monitoring. At a fixed electrospinning recipe, we showed that decreasing the RH from approximately 48% to 22% resulted in the average fiber diameter increasing from 240(±11) nm to 314(±8) nm. We also demonstrate the usefulness of our design in performing sequential electrospinning experiments to evaluate process performance reproducibility. For example, from just 1mL of a polymer solution, we produced 16 electrospun films (approximately 3cm by 8cm each)-from those films we hole-punched approximately 80 biosensor discs which were then used in subsequent experiments to determine the amount of two different biocides (Grotan BK and triclosan) in aqueous samples. The technique developed in this study is ideal for creating electrospun materials in high quantities that are highly reproducible through the precise control of RH.

Janus photothermal adsorbent for solar-powered simultaneous uranium extraction and co-production of freshwater and sea salt from seawater

Ocean reserves massive water and mineral resources. The success in uranium extraction and desalination from seawater is expected to alleviate the severe situation of energy and freshwater scarcities around the world. Herein, a novel Janus photothermal adsorbent was fabricated via sequential electrospinning for simultaneous uranium extraction and co-production of freshwater and sea salt from seawater. It consisted of a hydrophilic polyamidoxime (PAO) nanofibrous mat as the bottom layer for uranyl ion adsorption and a hydrophobic polyvinylidene fluoride (PVDF)/MXene (Ti3C2Tx) composite nanofibrous mat as the upper layer to capture and convert solar energy to heat. With the assistance of 1-sun illumination, the Janus adsorbent exhibited 6.05 mg g−1 of uranium adsorption capacity within 28 days from natural seawater, resulting in a 30.1 % increase compared to that in dark and achieved 1.36 kg m–2h−1 of water evaporation rate in natural seawater. An outdoor solar-powered adsorption coupling with evaporation test of this Janus adsorbent demonstrates that 6.40 kg m−2 of freshwater, 2.02 mg m−2 of uranium and 0.22 kg m−2 of sea salt were co-produced within 9 h operation. This study on the Janus adsorbent paves a promising way to the comprehensive development of ocean resources in low-carbon and sustainable strategy.

Prussian blue analog‐derived bimetallic phosphide nanoparticles anchored in nitrogen‐doped porous electrospun carbon nanofibers for efficient oxygen evolution reaction

Prussian blue analogs (PBAs) and their derivatives have been extensively investigated as potential oxygen evolution reaction (OER) electrocatalysts due to their high specific surface areas, adjustable composition, and controllable morphology, yet they suffer from easy aggregation and poor electrical conductivity. Herein, we successfully synthesized PBA‐derived NiFe bimetallic phosphide nanoparticles encapsulated in porous nitrogen‐doped electrospun carbon nanofibers by sequential electrospinning, carbonization, and phosphorization. By exploring the effects of different phosphating temperatures on electrocatalytic performance, the obtained electrocatalyst possesses a low overpotential of 262 mV at 10 mA cm−2 for OER in 1.0 M KOH. The electrospun carbon nanofibers can not only address the problem of poor electrical conductivity of PBA derivatives but also provide confinement effect, which could reduce PBA aggregation and collapse. Furthermore, the coupling effect of porous nitrogen‐doped electrospun carbon nanofibers and PBA‐derived bimetallic phosphide nanoparticles facilitates sufficient exposure of active species, expedites electron transfer, accelerates reaction kinetics, and improves durability.

Triple-layer nanofiber membrane with improved energy efficiency for treatment of hypersaline solution via membrane distillation

A new triple-layer, electrospun nanofiber membrane was fabricated in sequential electrospinning steps for enhancing the thermal efficiency of the membrane for desalination of high-salinity solution in a membrane distillation process. The membrane structure is designed to form a Janus structure comprised of two hydrophobic layers made of polyvinylidene fluoride and polystyrene at the top and middle, respectively, and one hydrophilic layer made of polyacrylonitrile at the bottom layer (support). The low thermal conductivity of the polystyrene layer and the Janus structure of the membrane could considerably enhance the flux and thermal performance of the membrane for desalination of hypersaline solution. The experimental results demonstrated that the designed membrane achieved high permeate flux and high energy efficiency compared with single and dual-layer membranes when used for treatment of high salinity solution. The results further showed that increasing feedwater salinity dropped the permeate flux of the single-layer membrane by over 50 % and reached 10 L/m2h, while for the triple-layer membrane, it just dropped 20 % for the feed salinity of 200 g/l. Moreover, the triple-layer membrane showed 20 % higher energy efficiency at the same operation conditions. Furthermore, a simulation model was developed and validated via the experimental results to understand the effect of various parameters.

A unidirectional drug‐release Janus membrane based on hydrogen bonding barrier effect for preventing postoperative adhesion and promoting tissue repair

AbstractBarrier membranes incorporated with anti‐adhesion drugs have been widely used for preventing postoperative adhesion. However, the bidirectional release of drugs may interfere with internal tissue healing. Herein, a unidirectional Janus membrane composed of two functional layers is prepared by sequential electrospinning. The outer layer is designed as random polycaprolactone fibers incorporated with tannic acid/Fe3+ particles to prevent tissue adhesion, while the inner layer is designed as oriented gelatin fibers to promote tissue repair. Hydrogen bonding was employed to act as a barrier for preventing the diffusion of the tannic acid to the inner side, and thus the release of tannic acid occurs in a unidirectional manner. As a result, asymmetric biological performances of the Janus membrane are achieved. The outer face can provide anti‐inflammatory capability to the membrane and inhibit the viability of fibroblasts, while the inner face can promote the proliferation and differentiation of tendon stem cells. Tendon injured model confirms the prominent inflammation modulation, adhesion prevention, and repair promotion capabilities of the Janus membrane in vivo. This study provides a new strategy to develop advanced functional barrier membranes for postoperative adhesion prevention and internal tissue repair promotion.

Multi-functional nanofiber membranes with asymmetric wettability and pine-needle-like structure for enhanced moisture-wicking

Developing air cleaning membranes that simultaneously meet the needs of efficient moisture transfer, particulate matter (PM) filtration, and bacterial inhibition still faces great challenges. Herein, a membrane with asymmetric wettability and pine-needle-like nanorods (NRs) was successfully prepared through hydrothermal treatment following sequential electrospinning. The zinc oxide (ZnO) nanorods, in-situ grown on the hydrophilic polyacrylonitrile (PAN) fibers, guide water transfer by extending to hydrophobic polyvinylidene fluoride (PVDF) channels, enhancing unidirectional water transport. Meanwhile, the ZnO nanorods also release antibacterial active ingredients and increase the contact between fibers and aerosols, so harmful microbes are deactivated after the aerosols are captured by the membrane. Consequently, the PVDF/(ZnO NRs@PAN) membrane exhibits an excellent water vapor transport rate (12.47 kg m−2 d−1), PM0.3 removal efficiency (99.83%), and bacteria inhibition rate (99.99%). Moreover, the membrane maintains high filtration performance after 10-cycle filtration and cleaning. Thus, the membrane shows extensive application prospects in the scenario that involves aerosol filtration, moisture management, and microbe inhibition, such as masks, protective clothing, and fresh air systems. This work paves the way for developing multi-functional air cleaning membranes with asymmetric wettability, based on interface design and microstructure regulation.

Electrospun gelatin-based biomimetic scaffold with spatially aligned and three-layer architectures for vascular tissue engineering

The spatial cellular alignment and multi-layer structure are vitally important for the physiological functions of natural blood vessels. However, the two features are difficult to be constructed in one scaffold simultaneously, especially in the small-diameter vascular scaffold. Here we report a general strategy to construct a gelatin-based biomimetic three-layer vascular scaffold with spatial alignment features mimicking the natural structure of blood vessels. By using a sequential electrospinning strategy combined with folding and rolling manipulation, a three-layer vascular scaffold with inner and middle layers spatially perpendicular to each other was obtained. The special features of this scaffold could fully mimic the natural multi-layer structures of blood vessels and also possess great potential for spatial arrangement guidance of corresponding cells in blood vessels.

A Sequential Electrospinning of a Coaxial and Blending Process for Creating Double-Layer Hybrid Films to Sense Glucose.

This study presents a glucose biosensor based on electrospun core-sheath nanofibers. Two types of film were fabricated using different electrospinning procedures. Film F1 was composed solely of core-sheath nanofibers fabricated using a modified coaxial electrospinning process. Film F2 was a double-layer hybrid film fabricated through a sequential electrospinning and blending process. The bottom layer of F2 comprised core-sheath nanofibers fabricated using a modified process, in which pure polymethacrylate type A (Eudragit L100) was used as the core section and water-soluble lignin (WSL) and phenol were loaded as the sheath section. The top layer of F2 contained glucose oxidase (GOx) and gold nanoparticles, which were distributed throughout the polyvinylpyrrolidone K90 (PVP K90) nanofibers through a single-fluid blending electrospinning process. The study investigated the sequential electrospinning process in detail. The experimental results demonstrated that the F2 hybrid film had a higher degradation efficiency of β-D-glucose than F1, reaching a maximum of over 70% after 12 h within the concentration range of 10-40 mmol/L. The hybrid film F2 is used for colorimetric sensing of β-D-glucose in the range of 1-15 mmol/L. The solution exhibited a color that deepened gradually with an increase in β-D-glucose concentration. Electrospinning is flexible in creating structures for bio-cascade reactions, and the double-layer hybrid film can provide a simple template for developing other sensing nanomaterials.

Trilayer Tubular Scaffold to Mimic Ductal Carcinoma Breast Cancer for the Study of Chemo-Photothermal Therapy

Ductal carcinoma in situ (DCIS) is a type of breast cancer resulting from malignant epithelial cells, which can become aggressive and dangerous over time due to the accumulation of cells in ducts. Finding more fruitful therapeutic strategies is a current demand in the field, and developing tumor models is a crucial approach to providing a suitable platform to investigate therapeutic strategies. Herein, a trilayer tubular 3D scaffold was developed as a DCIS model to imitate a real complex tissue microenvironment for cancerous cell culturing and treatment by chemo-photothermal therapy. The fabricated trilayer tubular scaffold through the sequential electrospinning consists of PLA/PCL nanofibers as a middle layer surrounded by alginate-dopamine/PVA nanofibers as outer and inner layers. The middle layer gives dimensional and mechanical stability to the scaffold, and its hydrophobicity can be balanced by two surrounding hydrophilic outer and inner layers to provide a suitable microenvironment for cell growth. Furthermore, the electrospun nanofibrous scaffold can mimic and resemble the microstructure of natural extracellular matrix (ECM) architecture to enhance cell proliferation. Then, the inner and outer layers were decorated with polydopamine nanoparticles to introduce photothermal ability and to improve cell adhesion. MDA-MB-231 breast cancer cells were cultured on the scaffold, and in vitro assays disclosed that the cells grew and expanded well on the scaffold. Concomitant administration of docetaxel and laser irradiation on the cultured cells on the scaffold (chemo-photothermal therapy) unveiled a synergistic inhibitory effect on cancer cells. These capabilities make the 3D trilayer tubular scaffold a promising platform for drug discovery and screening studies.

Multifunctional electrospun membranes with hydrophilic and hydrophobic gradients property for wound dressing

Achieving sustained and stable release of macromolecular antibacterial agents and unidirectional transport of liquids in targeted environment is still a challenge to be addressed in the management of wounds with large amounts of tissue exudates. In this work, a multilayer electrospun membrane (ethylcellulose-ethylcellulose/gelatin-quercetin/Eudragit L-100/polyethylene glycol, EC-EC/Gel-Q/EL/PEG) was designed with hydrophobic-hydrophilic gradients and drug sustained-release properties controlled by self-pumping effect and prepared using sequential electrospinning technology. The capillary force of different layers in the multilayer membrane could be controlled by precisely tuning the polymer concentrations of the inner and middle layers to extract water directly from hydrophobic inner ethylcellulose (EC) layer to hydrophilic middle ethylcellulose/gelatin (EC/Gel) layer. The droplets could not penetrate the hydrophobic side, but the drug molecules in the outer layer quercetin-loaded Eudragit L-100 (Q/EL/PEG) membrane moved after absorbing a large amount of water. The drug release behavior of multilayer wound dressing mainly followed the Korsmeyer-Peppas model. This multifunctional electrospun membrane could rapidly drive the biofluid outflow, effectively block the invasion of external contaminants and continuously release anti-inflammatory drugs, without any obvious cytotoxicity to mouse fibroblast cells. Hence, the above results indicate the excellent therapeutic potential of the proposed biomaterial as a wound dressing for diabetic patients.

Design and Modification of Janus Polyvinylidene Fluoride/Deacetylated Cellulose Acetate Nanofiber Membrane and its Multifunctionality

AbstractA novel type of Janus polyvinylidene fluoride/deacetylated cellulose acetate (PVDF/D‐CA) nanofiber membrane with multifunctional application is successfully fabricated by sequential electrospinning. The morphology, chemical composition, surface wettability, oil–water separation performance, and unidirectional liquid transmission capability have been systematically analyzed. It has asymmetric wettability property in air and in liquid systems for its bottom and top sides. It can be used as a water‐removing, or oil‐removing substance for oil–water mixture and emulsion under a harsh environment only under gravity driving force (DF) by simply switching the different sides. It possesses on‐demand water and oil collection ability, and moisture‐wicking performance due to its switchable permeation and unidirectional liquid transmission capability. Its multifunction application can be easy to control by adjusting the thickness of the top and bottom sides through controlling the electrospinning time. Its excellent mechanical property, chemical stability, durability under harsh environment and outstanding anti‐pollution ability endow the membrane with powerful cyclic stability and reusability.