Wound Dressing with Electrospun Core-Shell Nanofibers: From Material Selection to Synthesis

Skin, the largest organ of the human body, accounts for protecting against external injuries and pathogens. Despite possessing inherent self-regeneration capabilities, the repair of skin lesions is a complex and time-consuming process yet vital to preserving its critical physiological functions. The dominant treatment involves the application of a dressing to protect the wound, mitigate the risk of infection, and decrease the likelihood of secondary injuries. Pursuing solutions for accelerating wound healing has resulted in groundbreaking advancements in materials science, from hydrogels and hydrocolloids to foams and micro-/nanofibers. Noting the convenience and flexibility in design, nanofibers merit a high surface-area-to-volume ratio, controlled release of therapeutics, mimicking of the extracellular matrix, and excellent mechanical properties. Core-shell nanofibers bring even further prospects to the realm of wound dressings upon separate compartments with independent functionality, adapted release profiles of bioactive agents, and better moisture management. In this review, we highlight core-shell nanofibers for wound dressing applications featuring a survey on common materials and synthesis methods. Our discussion embodies the wound healing process, optimal wound dressing characteristics, the current organic and inorganic material repertoire for multifunctional core-shell nanofibers, and common techniques to fabricate proper coaxial structures. We also provide an overview of antibacterial nanomaterials with an emphasis on their crystalline structures, properties, and functions. We conclude with an outlook for the potential offered by core-shell nanofibers toward a more advanced design for effective wound healing.

Nanoporous air filtering systems made from renewable sources: benefits and challenges

There is a crucial need for air purification systems due to increasing air contamination, while conventional air-filtering materials face challenges in eliminating gaseous and particulate pollutants. This review examines the development and characteristics of nanoporous polymeric materials developed from renewable resources, which have rapidly advanced in recent years. These materials offer more sustainable alternatives for nanoporous structures made out of conventional polymers and significantly impact the properties of porous polymers. The review explores nanoporous materials' production from renewable sources, filtering mechanisms, physicochemical makeup, and sensing capabilities. The recent advancements in this field aim to enhance production techniques, lower pressure drop, and improve adsorption efficiency. Currently, supporting approaches include using adsorbent layers and binders to immobilize nanoporous materials. Furthermore, the prospects and challenges of nanoporous materials obtained from renewable sources used for air purification are discussed.

Fabrication of a sensitive electrochemical sensor based on hybrid polyamide/chromotropic acid nanofibers electrospun on glassy carbon electrode for Hg2+ sensing in drinking water and canned fish samples

In this study, a new electrochemical sensor was designed based on a hybrid of polyamide (PA) and chromotropic acid (CA) nanofibers electrospun on a glassy carbon electrode (GCE) configured as PANFs-CANFs/GCE. The electrochemical response of this sensor showed an excellent electrochemical activity for the detection of Hg²⁺ ions using cyclic voltammetry (CV) and differential pulse voltammetry (DPV) methods. The proposed sensor exhibited the prominent electrocatalytic value of (α = 0.60, Log Ks = 3.45 s^-1 and Γ = 3.30 × 10 ^-9 mmol/cm²) as a result of PANFs-CANFs/GCE response to Hg²⁺ ions. The recommended sensor also demonstrated a linear portion in the calibration curve over the concentration range of 30 to 450 nM with the limit of detection (LOD) and limit of quantitation (LOQ) of 9.98 nM and 29.97 nM, respectively. The fabricated sensor revealed reproducible and repeatable responses with a high level of stability. Therefore, we highly recommend this new electro-spun based sensor for quantifying Hg²⁺ in drinking water and canned fish samples with the accurate and precise results and no side interferences.

Bioelectrets in Electrospun Bimodal Poly(lactic acid) Fibers: Realization of Multiple Mechanisms for Efficient and Long-Term Filtration of Fine PMs

Despite the great potential in fabrication of biodegradable and eco-friendly air filters by electrospinning poly(lactic acid) (PLA) membranes, the filtering performance is frequently dwarfed by inadequate physical sieving or electrostatic adsorption mechanisms to capture airborne particulate matters (PMs). Here, using the parallel spinning approach, the unique micro/nanoscale architecture was established by conjugation of neighboring PLA nanofibers, creating bimodal fibers in electrospun PLA membranes for the enhanced slip effect to significantly reduce the air resistance. Moreover, the bone-like nanocrystalline hydroxyapatite bioelectret (HABE) was exploited to enhance the dielectric and polarization properties of electrospun PLA, accompanied by the controlled generation of junctions induced by the microaggregation of HABE (10-30 wt %). The incorporated HABE was supposed to orderly align in the applied E-field and largely promote the charging capability and surface potential, gradually increasing to 7.2 kV from the lowest level of 2.5 kV for pure PLA. This was mainly attributed to HABE-induced orientation of PLA backbone chains and C═O dipoles, as well as the interfacial charges trapped at the interphases of HABE-PLA and crystalline region-amorphous PLA. Given the multiple capturing mechanisms, the micro/nanostructured PLA/HABE membranes were characterized by excellent and sustainable filtering performance, e.g., the filtration efficiency of PM_0.3 was promoted from 59.38% for pure PLA to 94.38% after addition of 30 wt % HABE at a moderate airflow capacity of 32 L/min and from 30.78 to 83.75% at the highest level of 85 L/min. It is of interest that the pressure drop was significantly decreased, mainly arising from the slip effect between the ultrafine nanofibers and conjugated microfibers. The proposed combination of the nanostructured electret and the multistructuring strategy offers the function integration of efficient filtration and low resistance that are highly useful to pursue fully biodegradable filters.

Cellulose Nanocrystals as Additives in Electrospun Biocompatible Separators for Aprotic Lithium-Ion Batteries

This work concerns the study of electrospun scaffolds as separators for aprotic lithium-ion batteries (LIBs) composed of the amorphous poly-d,l-lactide (PDLLA), in solution concentrations of 8, 10, and 12 wt % and in different ratios with cellulose nanocrystals (CNCs). PDLLA has been studied for the first time as a separator, taking into account its amorphous character that could facilitate electrolyte incorporation into the polymer matrix and influence ionic conductivity, together with CNCs, for reducing the hydrophobicity of the scaffolds. The embedding of the nanocrystals in the scaffolds was confirmed by X-ray diffraction analysis and attenuated total reflectance Fourier transform infrared spectroscopy. The polymer combination influenced the nanofibrous morphology as evaluated by scanning electron microscopy and modulated the electrochemical behavior of the membranes that was investigated through linear sweep voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy tests. Among the studied categories, the P12 series displayed a nonhomogeneous electrolyte resistance and electrochemical stability, differently from P10, whose results suggested their application in LIBs with standard formulation, as confirmed by a preliminary performance test of the P10N6 formulation in a full Li-ion cell configuration.

Tailoring micro/nano-fibers for biomedical applications

Nano/micro fibers have evoked much attention of scientists and have been researched as cutting edge and hotspot in the area of fiber science in recent years due to the rapid development of various advanced manufacturing technologies, and the appearance of fascinating and special functions and properties, such as the enhanced mechanical strength, high surface area to volume ratio and special functionalities shown in the surface, triggered by the nano or micro-scale dimensions. In addition, these outstanding and special characteristics of the nano/micro fibers impart fiber-based materials with wide applications, such as environmental engineering, electronic and biomedical fields. This review mainly focuses on the recent development in the various nano/micro fibers fabrication strategies and corresponding applications in the biomedical fields, including tissue engineering scaffolds, drug delivery, wound healing, and biosensors. Moreover, the challenges for the fabrications and applications and future perspectives are presented.

Electrospun composite nanofibers as novel high-performance and visible-light photocatalysts for removal of environmental pollutants: A review

Environmental pollution caused by industries and human manipulations is coming a serious global challenge. On the other hand, the world is facing an energy crisis caused by population growth. Designing solar-driven photocatalysts which are inspired by the photosynthesis of plant leaves is a fantastic solution to use solar energy as green, available, and unlimited energy containing ∼50% visible light for the removal of environmental pollutants. The polymeric and non-polymeric-based electrospun composite nanofibers (NFs) are as innovative photocatalytic candidates which increase photocatalytic activity and transition from UV light to visible light and overcome the aggregation, photocorrosion, toxicity, and hard recycling and separation of the nanosized powder form of photocatalysts. The composite NFs are fabricated easily by either embedding the photocatalytic agents into the NFs during electrospinning or via their decorating on the surface of NFs post-electrospinning. Polyacrylonitrile-based, tungsten trioxide-based, zinc oxide-based, and titanium dioxide-based composite NFs were revealed as the most reported composite NFs. All the lately investigated electrospun composite NFs indicated long-term stability, high photocatalytic efficiency (∼> 80%) within a short time of light radiation (10-430 min), and high stability after several cycles of use. They were applied in various applications including degradation of dyes/antibiotics, water splitting, wastewater treatment, antibacterial usage, etc. The photogenerated species especially holes, O₂^∙-, and ^.OH were mostly responsible for the photocatalytic mechanism and pathway. The electrospun composite NFs have the potential to use in large-scale productions in condition that their thickness and recycling conditions are optimized, and their toxicity and detaching are resolved.

Recent advances and remaining barriers to the development of electrospun nanofiber and nanofiber composites for point-of-use and point-of-entry water treatment systems

In this review, we focus on electrospun nanofibers as a promising material alternative for the niche application of decentralized, point-of-use (POU) and point-of-entry (POE) water treatment systems. We focus our review on prior work with various formulations of electrospun materials, including nanofibers of carbon, pure metal oxides, functionalized polymers, and polymer-metal oxide composites, that exhibit analogous performance to media (e.g., activated carbon, ion exchange resins) commonly used in commercially available, certified POU/POE devices for contaminants including organic pollutants, metals (e.g., lead) and persistent oxyanions (e.g., nitrate). We then analyze the relevant strengths and remaining research and development opportunities of the relevant literature based on an evaluation framework that considers (i) performance comparison to commercial analogs; (ii) appropriate pollutant targets for POU/POE applications; (iii) testing in flow-through systems consistent with POU/POE applications; (iv) consideration of water quality effects; and (v) evaluation of material strength and longevity. We also identify several emerging issues in decentralized water treatment where nanofiber-based POU/POE devices could help meet existing needs including their use for treatment of uranium, disinfection, and in electrochemical treatment systems. To date, research has demonstrated promising material performance toward relevant targets for POU/POE applications, using appropriate aquatic matrices and considering material stability. To fully realize their promise as an emerging treatment technology, our analysis of the available literature reveals the need for more work that benchmarks nanofiber performance against established commercial analogs, as well as fabrication and performance validation at scales and under conditions simulating POU/POE water treatment.

Electrospun Nanofiber Composites for Drug Delivery: A Review on Current Progresses

A medication’s approximate release profile should be sustained in order to generate the desired therapeutic effect. The drug’s release site, duration, and rate must all be adjusted to the drug’s therapeutic aim. However, when designing drug delivery systems, this may be a considerable hurdle. Electrospinning is a promising method of creating a nanofibrous membrane since it enables drugs to be placed in the nanofiber composite and released over time. Nanofiber composites designed through electrospinning for drug release purposes are commonly constructed of simple structures. This nanofiber composite produces matrices with nanoscale fiber structure, large surface area to volume ratio, and a high porosity with small pore size. The nanofiber composite’s large surface area to volume ratio can aid with cell binding and multiplication, drug loading, and mass transfer processes. The nanofiber composite acts as a container for drugs that can be customized to a wide range of drug release kinetics. Drugs may be electrospun after being dissolved or dispersed in the polymer solution, or they can be physically or chemically bound to the nanofiber surface. The composition and internal structure of the nanofibers are crucial for medicine release patterns.

Optimizing the structural properties of electrospun polyimide membranes by response surface method

Recently, there has been a rising tendency for the fabrication of membranes using the electrospinning method because it can control the properties of the fibrous mats by changing the parameters of the process. For this reason, in the current research, polyimide (PI) membranes were fabricated by the electrospinning method. The effect of electrospinning parameters on the content of porosity and tensile properties of the electrospun PI mats were investigated. Solution concentration, device voltage, and feed rate were considered the process parameters. Response surface methodology was adopted to design the electrospinning experiments. The results showed that the feed rate had the most contribution to the content of porosity of electrospun PI membranes which increased by decreasing the feed rate. On the other hand, the polymer concentration had a remarkable effect on the tensile strength. Indeed, the tensile strength improved as the solution concentration increased. The optimized electrospinning parameters to achieve both the highest porosity (97.66%) and the highest tensile strength (2.25 MPa) in the PI membrane were as follows: solution concentration 16.78%wt, device voltage 17 kV, and feed rate 1.4 mL h−1. The experimental results were in good agreement with the predicted values.

Biomaterials Used for Periodontal Disease Treatment: Focusing on Immunomodulatory Properties

The growing use of biomaterials with different therapeutic purposes increases the need for their physiological understanding as well as to seek its integration with the human body. Chronic inflammatory local pathologies, generally associated with infectious or autoimmunity processes, have been a current therapeutic target due to the difficulty in their treatment. The recent development of biomaterials with immunomodulatory capacity would then become one of the possible strategies for their management in local pathologies, by intervening in situ, without generating alterations in the systemic immune response. The treatment of periodontal disease as an inflammatory entity has involved the use of different approaches and biomaterials. There is no conclusive, high evidence about the use of these biomaterials in the regeneration of periodontitis sequelae, so the profession keeps looking for other different strategies. The use of biomaterials with immunomodulatory properties could be one, with a promising future. This review of the literature summarizes the scientific evidence about biomaterials used in the treatment of periodontal disease.

Basic Principles of Electrospinning, Mechanisms, Nanofibre Production, and Anticancer Drug Delivery

Electrospun nanofibres are environmentally friendly compounds, when compared with other approaches of manufacturing nanofibres. This study reviews an easy and simple approach process of producing nanofibres called electrospinning. This review further gives an overview and successful methodical approaches to obtain electrospun (ES) nanofibres appropriate for anticancer drug delivery. The properties and characterization of electrospun nanofibres were reported to confirm successful nanofibre production. The application of characterized ES nanofibres is to deliver the anticancer drug to the right target in the human body. The implication of this study is the application of some of the merits of ES nanofibres (biocompatability, biodegradability, low-cost production, small pore size, and ability to transport anticancer drug to the target cell or organ) to overcome the challenges experienced in the use of anticancer chemotherapeutic agents.

Effectiveness of N95 Masks against SARS-CoV-2: Performance Efficiency, Concerns, and Future Directions

The coronavirus disease 2019 (COVID-19) epidemic, which is caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has continued to spread around the world since December 2019. Healthcare workers and other medical first responders in particular need personal protective equipment to protect their respiratory system from airborne particulates, in addition to liquid splashes to the face. N95 respirator have become a critical component for reducing SARS-CoV-2 transmission and controlling the scale of the COVID-19 pandemic. However, a major dispute concerning the protective performance of N95 respirators has erupted, with a myriad of healthcare workers affected despite wearing N95 masks. This article reviews the most recent updates about the performance of N95 respirators in protecting against the SARS-CoV-2 virus in the present pandemic situation. A brief overview of the manufacturing methods, air filtration mechanisms, stability, and reusability of the mask is provided. A detailed performance evaluation of the mask is studied from an engineering point of view. This Review also reports on a comparative study about the protective performance of all commercially available surgical and respiratory masks used to combat the spread of COVID-19. With the aim of protecting healthcare providers more efficiently, we suggest some potential directions for the development of this respiratory mask that improve the performance efficiency of the mask.

Electrospun Nanofiber Membranes for Air Filtration: A Review

Nanomaterials for air filtration have been studied by researchers for decades. Owing to the advantages of high porosity, small pore size, and good connectivity, nanofiber membranes prepared by electrospinning technology have been considered as an outstanding air-filter candidate. To satisfy the requirements of material functionalization, electrospinning can provide a simple and efficient one-step process to fabricate the complex structures of functional nanofibers such as core-sheath structures, Janus structures, and other multilayered structures. Additionally, as a nanoparticle carrier, electrospun nanofibers can easily achieve antibacterial properties, flame-retardant properties, and the adsorption properties of volatile gases, etc. These simple and effective approaches have benefited from the significate development of electrospun nanofibers for air-filtration applications. In this review, the research progress on electrospun nanofibers as air filters in recent years is summarized. The fabrication methods, filtration performances, advantages, and disadvantages of single-polymer nanofibers, multipolymer composite nanofibers, and nanoparticle-doped hybrid nanofibers are investigated. Finally, the basic principles of air filtration are concluded upon and prospects for the application of complex-structured nanofibers in the field of air filtration are proposed.

Recent Trends in Biosensors for Environmental Quality Monitoring

The monitoring of environmental pollution requires fast, reliable, cost-effective and small devices. This need explains the recent trends in the development of biosensing devices for pollutant detection. The present review aims to summarize the newest trends regarding the use of biosensors to detect environmental contaminants. Enzyme, whole cell, antibody, aptamer, and DNA-based biosensors and biomimetic sensors are discussed. We summarize their applicability to the detection of various pollutants and mention their constructive characteristics. Several detection principles are used in biosensor design: amperometry, conductometry, luminescence, etc. They differ in terms of rapidity, sensitivity, profitability, and design. Each one is characterized by specific selectivity and detection limits depending on the sensitive element. Mimetic biosensors are slowly gaining attention from researchers and users due to their advantages compared with classical ones. Further studies are necessary for the development of robust biosensing devices that can successfully be used for the detection of pollutants from complex matrices without prior sample preparation.

A comprehensive review on preparation, functionalization and recent applications of nanofiber membranes in wastewater treatment

The direct discharge of significant amounts of polluted water into water bodies causes adverse ecological and human health effects. This severe deterioration in water quality creates significant challenges to meet the growing demand for clean water. Therefore, the world urgently needs environmentally friendly advanced technology to overcome this global crisis. In this regard, nanofiber-based membrane filtration is a promising technique in wastewater remediation because of their huge surface area, extremely porous structure, amenable pore size/pore size distribution, variety of material choices, and flexibility to modification with other functional materials. However, despite their unique properties, fouling, poor mechanical properties, shrinkage, and deformation are major drawbacks of nanofiber membranes for treating wastewater. This review presents a comprehensive overview of nanofiber membranes' fabrication and function in water purification applications as well as providing novel approaches to overcoming/alleviating the mentioned disadvantages. The review first presents nanofiber membrane preparation methods, focusing on electrospinning as a versatile and viable technique alongside discussing the parameters controlling nanofiber morphology. Afterward, the functionalization of nanofiber membranes by combining them with other nanomaterials, such as metal and metal-oxide nanoparticles, carbon nanotubes, metal-organic frameworks, and biomolecules, were demonstrated and discussed. In addition, nanofiber membranes functionalized with microorganisms were highlighted. Finally, we introduced and discussed in detail the most relevant and recent advances in nanofiber applications in wastewater treatment in the context of removing different pollutants (e.g., heavy metals, nutrients, radioactive elements, pharmaceuticals, and personal care products, dyes, and pesticides). Moreover, the promising antimicrobial ability of nanofiber membranes in removing microorganisms from wastewater has been fully underscored. We believe this comprehensive review could provide researchers with preliminary data and guide both researchers and producers engaged in the nanofiber membrane industry, letting them focus on the research gaps in wastewater treatment.

Composite Fiber Spun Mat Synthesis and In Vitro Biocompatibility for Guide Tissue Engineering

Composite scaffolds are commonly used strategies and materials employed to achieve similar analogs of bone tissue. This study aims to fabricate 10% wt polylactic acid (PLA) composite fiber scaffolds by the air-jet spinning technique (AJS) doped with 0.5 or 0.1 g of zirconium oxide nanoparticles (ZrO₂) for guide bone tissue engineering. ZrO₂ nanoparticles were obtained by the hydrothermal method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). SEM and fourier-transform infrared spectroscopy (FTIR) analyzed the synthesized PLA/ZrO₂ fiber scaffolds. The in vitro biocompatibility and bioactivity of the PLA/ZrO₂ were studied using human fetal osteoblast cells. Our results showed that the hydrothermal technique allowed ZrO₂ nanoparticles to be obtained. SEM analysis showed that PLA/ZrO₂ composite has a fiber diameter of 395 nm, and the FITR spectra confirmed that the scaffolds’ chemical characteristics are not affected by the synthesized technique. In vitro studies demonstrated that PLA/ZrO₂ scaffolds increased cell adhesion, cellular proliferation, and biomineralization of osteoblasts. In conclusion, the PLA/ZrO₂ scaffolds are bioactive, improve osteoblasts behavior, and can be used in tissue bone engineering applications.

Organic/Inorganic Hybrid Fibers: Controllable Architectures for Electrochemical Energy Applications

Organic/inorganic hybrid fibers (OIHFs) are intriguing materials, possessing an intrinsic high specific surface area and flexibility coupled to unique anisotropic properties, diverse chemical compositions, and controllable hybrid architectures. During the last decade, advanced OIHFs with exceptional properties for electrochemical energy applications, including possessing interconnected networks, abundant active sites, and short ion diffusion length have emerged. Here, a comprehensive overview of the controllable architectures and electrochemical energy applications of OIHFs is presented. After a brief introduction, the controllable construction of OIHFs is described in detail through precise tailoring of the overall, interior, and interface structures. Additionally, several important electrochemical energy applications including rechargeable batteries (lithium-ion batteries, sodium-ion batteries, and lithium-sulfur batteries), supercapacitors (sandwich-shaped supercapacitors and fiber-shaped supercapacitors), and electrocatalysts (oxygen reduction reaction, oxygen evolution reaction, and hydrogen evolution reaction) are presented. The current state of the field and challenges are discussed, and a vision of the future directions to exploit OIHFs for electrochemical energy devices is provided.

Development and Advantages of Biodegradable PHA Polymers Based on Electrospun PHBV Fibers for Tissue Engineering and Other Biomedical Applications

Biodegradable polymeric biomaterials offer a significant advantage in disposable or fast-consuming products in medical applications. Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is an example of a polyhydroxyalkanoate (PHA), i.e., one group of natural polyesters that are byproducts of reactions taking place in microorganisms in conditions with an excess carbon source. PHA polymers are a promising material for the production of everyday materials and biomedical applications. Due to the high number of monomers in the group, PHAs permit modifications enabling the production of copolymers of different compositions and with different proportions of individual monomers. In order to change and improve the properties of polymer fibers, PHAs are combined with either other natural and synthetic polymers or additives of inorganic phases. Importantly, electrospun PHBV fibers and mats showed an enormous potential in both the medical field (tissue engineering scaffolds, plasters, wound healing, drug delivery systems) and industrial applications (filter systems, food packaging). This Review summarizes the current state of the art in processing PHBV, especially by electrospinning, its degradation processes, and biocompatibility studies, starting from a general introduction to the PHA group of polymers.

Optically activated and interrogated plasmonic hydrogels for applications in wound healing

We disclose the use of hybrid materials featuring Au/Ag core/shell nanorods in porous chitosan/polyvinyl alcohol scaffolds for applications in tissue engineering and wound healing. The combination of Au and Ag in a single construct provides synergistic opportunities for optical activation of functions as near infrared laser tissue bonding, and remote interrogation to return parameters of prognostic relevance in wound healing monitoring. In particular, the bimetallic component ensures optical tunability, enhanced shelf life and photothermal stability, serves as a reservoir of germicidal silver cations, and changes in near-infrared and visible color according to the environmental level of oxidative stress. At the same time, the polymeric blend is ideal to bind connective tissue upon photothermal activation, and to support fabrication processes that provide high porosity, such as electrospinning, thus putting all the premises for cellular repopulation and antimicrobial protection.

Electrochemical Response of Highly Porous Percolative CGO Electrospun Membranes

Electrochemical Impedance Spectroscopy (EIS) is here used to characterize highly porous Ce0.9Gd0.1O1.95 (CGO, ca. 90% vol. of porosity) free-supporting nano-fibrous thick (100μm) membranes, fabricated via an electrospinning technique. The investigation of the calcination temperature influence on the microstructure indicates an evolution of the single nanofiber’s microstructure with a gradual grain growth from densely packed polycrystalline to pearl collar-like structures at increasing temperatures. This evolution is accompanied by brittleness for samples treated at temperatures above 800 °C. The electrochemical characterization suggests an ionic percolative conductivity that exploits both the bulk-lattice conduction along the individual nanofibers and interfacial conduction across different nanofibers at their intersections. Optimized membranes treated at 600 and 700 °C exhibit a similar electrochemical bulk response, but different interfacial electrochemical behavior (low frequency) associated with a grain size effect.

Electrospun fibers based on carbohydrate gum polymers and their multifaceted applications

Electrospinning has garnered significant attention in view of its many advantages such as feasibility for various polymers, scalability required for mass production, and ease of processing. Extensive studies have been devoted to the use of electrospinning to fabricate various electrospun nanofibers derived from carbohydrate gum polymers in combination with synthetic polymers and/or additives of inorganic or organic materials with gums. In view of the versatility and the widespread choice of precursors that can be deployed for electrospinning, various gums from both, the plants and microbial-based gum carbohydrates are holistically and/or partially included in the electrospinning solution for the preparation of functional composite nanofibers. Moreover, our strategy encompasses a combination of natural gums with other polymers/inorganic or nanoparticles to ensue distinct properties. This early established milestone in functional carbohydrate gum polymer-based composite nanofibers may be deployed by specialized researchers in the field of nanoscience and technology, and especially for exploiting electrospinning of natural gums composites for diverse applications.

Electrospun CNF Supported Ceramics as Electrochemical Catalysts for Water Splitting and Fuel Cell: A Review

With the per capita growth of energy demand, there is a significant need for alternative and sustainable energy resources. Efficient electrochemical catalysis will play an important role in sustaining that need, and nanomaterials will play a crucial role, owing to their high surface area to volume ratio. Electrospun nanofiber is one of the most promising alternatives for producing such nanostructures. A section of key nano-electrocatalysts comprise of transition metals (TMs) and their derivatives, like oxides, sulfides, phosphides and carbides, etc., as well as their 1D composites with carbonaceous elements, like carbon nanotubes (CNTs) and carbon nanofiber (CNF), to utilize the fruits of TMs’ electronic structure, their inherent catalytic capability and the carbon counterparts’ stability, and electrical conductivity. In this work, we will discuss about such TM derivatives, mostly TM-based ceramics, grown on the CNF substrates via electrospinning. We will discuss about manufacturing methods, and their electrochemical catalysis performances in regards to energy conversion processes, dealing mostly with water splitting, the metal–air battery fuel cell, etc. This review will help to understand the recent evolution, challenges and future scopes related to electrospun transition metal derivative-based CNFs as electrocatalysts.

Functionalized Electrospun Nanofibers as Colorimetric Sensory Probe for Mercury Detection: A Review

Mercury is considered the most hazardous pollutant of aquatic resources; it exerts numerous adverse effects on environmental and human health. To date, significant progress has been made in employing a variety of nanomaterials for the colorimetric detection of mercury ions. Electrospun nanofibers exhibit several beneficial features, including a large surface area, porous nature, and easy functionalization; thus, providing several opportunities to encapsulate a variety of functional materials for sensing applications with enhanced sensitivity and selectivity, and a fast response. In this review, several examples of electrospun nanofiber-based sensing platforms devised by utilizing the two foremost approaches, namely, direct incorporation and surface decoration envisioned for detection of mercury ions are provided. We believe these examples provide sufficient evidence for the potential use and progress of electrospun nanofibers toward colorimetric sensing of mercury ions. Furthermore, the summary of the review is focused on providing an insight into the future directions of designing electrospun nanofiber-based, metal ion colorimetric sensors for practical applications.

Microphase separation in oriented polymeric chains at the surface of nanomaterials during nanofiber formation

The presence of low-dimensional functional nanofillers during the formation of morphological phase boundaries in polymeric nanofibers by electrospinning was highlighted in this study. PAN and TPU were both selected with differential viscosities to understand the phase-segregated internal supramolecular structures on functional surfaces of different length scales. The low-dimensional carbon nanofillers displayed a significant role in the topological orientation of the polymeric chains in TPU due to the presence of hard and soft segments in the geometry of TPU. The nano-hybrid shish-kebab-type microphase separation was observed on 1D nanofillers, whereas the anisotropic hierarchical microdomains were formed in the presence of 0D nanofillers. The 2D functional surface produced highly folded nanoscale lamellae by molecular interactions with polymeric chains. By combining different dimensional nanofillers, the hybrid 1D-2D networks created multifaceted structural hierarchies with epitaxial growth on the planar surface and shish-kebab geometry on the 1D functional backbone. Our study has demonstrated the significance of the configuration of nanoscale functional surfaces on the texture of polymeric chain assemblies during electrospinning for controlled flexible scaffolds.

Electrochemical Sensors Fabricated by Electrospinning Technology: An Overview

Nanofibers or nanofibrous membranes prepared by electrospinning possess many attractive properties, including excellent mechanical properties, high specific surface area and high porosity, making them attractive for sensor application, especially for the electrochemical sensors. Many nanomaterials are used as additives to improve the conductivity, sensitivity and selectivity of sensors. Based on the different modifiers of electrode materials, electrochemical sensors can be divided into enzyme sensors and non-enzyme sensors. In this review, we summarize the recent progress of the electrochemical sensors fabricated by electrospinning, including hydrogen peroxide (H2O2) sensors, glucose sensors and other sensors. In addition, the sensing mechanisms of various electrochemical sensors are introduced in detail. Finally, future research directions of electrochemical sensors based on electrospinning and the challenges faced by large-scale applications of electrospun electrochemical sensors are presented.

Adhesion strength and viscoelastic properties of polydimethylsiloxane (PDMS) based elastomeric nanocomposites with embedded electrospun nanofibers

In the present study, the adhesive and viscoelastic properties of polydimethylsiloxane (PDMS) based nanocomposite pressure sensitive adhesives (PSAs) with embedded electrospun polyacrylonitrile (PAN) and polyvinyl alcohol (PVA) nanofibers as fillers were investigated. PDMS nanocomposite adhesive films using PAN and PVA nanofibers were synthesized by dispersing fillers in the matrix by a solvent mixing process. The adhesion strength and reusability of the prepared nanocomposite PSA films were measured using peel tests as the fraction of nanofibers in the polymer matrix is increased. The variations of the adhesive properties of the PSAs as function of the type and loading of filler were related to their rheological properties in terms of shear and elastic moduli. Although 3-fold enhancement of the adhesion strength was achieved with 0.5 wt% loading for both types (PAN and PVA) of nanocomposites as compared to elastic PDMS, the composite adhesive with PAN nanofibers can provide a superior balance of rheological properties, resulting in improved reusability over other PSAs. The differences in the adhesion and viscoelastic properties of the composite PSAs are attributed to the polymer chemistry, processability, and architecture of the electrospun nanofibers in the soft PDMS matrix.

Tuning Porosity and Functionality of Electrospun Rubber Nanofiber Mats by Photo-Crosslinking

The present work proposes a versatile and efficient method to fabricate rubber nanofiber membranes with a controlled morphology and tailored functionality, based on the application of photoinduced thiol-ene cross-linking reactions to electrospun mats. Besides preventing the polymer cold flow and freezing the structure obtained by electrospinning, the photocuring step finely controls the morphology of the nanofiber mats, in terms of the fiber diameter up to the nanometer range and of the membrane porosity. Nanofiber membranes are also made chemically resistant, while retaining their flexibility. Finally, the proposed approach allows imparting specific functionalities to the rubber nanofibers: the type and concentration of the functional groups can be precisely tuned by changing process parameters (i.e., thiol/ene stoichiometric ratio and irradiation dose). Active chemical groups that remain available on the surface of the nanofibers can be used for further material modifications, as here proven by two target reactions. This key result is also demonstrated with electrospun membranes embedded into a microfluidic chip, opening the way to advanced functional flexible devices.

Electrospun Gelatin Fibers Surface Loaded ZnO Particles as a Potential Biodegradable Antibacterial Wound Dressing

Traditional wound dressings require frequent replacement, are prone to bacterial growth and cause a lot of environmental pollution. Therefore, biodegradable and antibacterial dressings are eagerly desired. In this paper, gelatin/ZnO fibers were first prepared by side-by-side electrospinning for potential wound dressing materials. The morphology, composition, cytotoxicity and antibacterial activity were characterized by using Fourier transform infrared spectroscopy (FTIR), X-ray diffractometry (XRD), particle size analyzer (DLS), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), thermogravimetry (TGA) and Incucyte™ Zoom system. The results show that ZnO particles are uniformly dispersed on the surface of gelatin fibers and have no cytotoxicity. In addition, the gelatin/ZnO fibers exhibit excellent antibacterial activity against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) with a significant reduction of bacteria to more than 90%. Therefore, such a biodegradable, nontoxic and antibacterial fiber has excellent application prospects in wound dressing.