Multi-functional electrospun nanofibres for advances in tissue regeneration, energy conversion & storage, and water treatment

Multifunctional Conductive Nanofibers for Self-Powered Glucose Biosensors

Electrochemical glucose biosensors are essential for diabetes management, and self-powered systems present an eco-friendly and innovative alternative. Traditional biosensors face several limitations including limited sensitivity, enzyme instability, and dependency on external power sources. Addressing these issues, the study develops a novel multifunctional nanofiber integrating biosensor for glucose detection and a self-powered motion sensor, utilizing an innovative triboelectric nanogenerator (TENG) system. Electrospun nanofibers, composed of graphene oxide (GO), porous graphene (PG), graphene foam (GF), polypyrrole (PPy), and polycaprolactone (PCL), demonstrate enhanced electrical conductivity, triboelectric efficiency, and mechanical strength. Among these, dip-coated nanofibers exhibited the highest conductivity of 4.9 × 10⁻⁵ S/cm, attributed to superior surface electrical properties of GO. PCL/PPy/GO nanofibers achieved the highest glucose detection performance in cyclic voltammetry and differential pulse voltammetry due to efficient electron transfer mechanisms of GO and PPy. Additionally, triboelectric tests revealed peak voltages of 63V with PCL/PPy/GO and polyvinylidene fluoride nanofibers containing glucose oxidase enzyme. Core-sheath and dip-coated nanofibers also demonstrated significant mechanical resilience (∼0.9 N force, ∼350 s durability). These findings highlight PCL/PPy/GO nanofibers as a multifunctional, efficient, and scalable solution, offering highly sensitive glucose detection and non-invasive sweat analysis along with robust energy harvesting for environmentally friendly and advanced diabetes management systems.

Advancements, functionalization techniques, and multifunctional applications in biomedical and industrial fields of electrospun pectin nanofibers: A review

Electrospun pectin nanofibers have emerged as a transformative advancement in biomaterials, offering remarkable potential across diverse biomedical and industrial applications. This review explores the synthesis, optimization, and versatile applications of electrospun pectin nanofibers, highlighting their unique properties, including biocompatibility, biodegradability, and adaptability for functionalization. Pectin's structural diversity, coupled with its ability to form hydrogels and interact with biological systems, makes it a promising candidate for wound healing, drug delivery, tissue engineering, and smart packaging. Electrospinning has enabled the fabrication of pectin nanofibers with tunable morphology and functionality, overcoming traditional limitations such as poor mechanical strength. Advances in blending pectin with other polymers and incorporating bioactive agents have further enhanced their mechanical, biological, and therapeutic properties. In wound healing, pectin nanofibers mimic the extracellular matrix, promote angiogenesis, and deliver bioactive compounds to accelerate tissue regeneration. Challenges such as scalability, regulatory compliance, and mechanical limitations remain barriers to widespread adoption. This review underscores the need for interdisciplinary research to address these challenges and advance the clinical and commercial translation of pectin nanofibers. By critically analyzing recent advancements and outlining future directions, this review highlights the transformative potential of electrospun pectin nanofibers as sustainable, high-performance biomaterials for modern biomedical and industrial applications.

Intrinsically Healable and Photoresponsive Electrospun Fabrics: Integrating PVDF-HFP, TPU, and Azobenzene Ionic Liquids

In recent years, the integration of multifunctional properties into electrospun fabrics has garnered significant attention for applications in wearable devices and smart textiles. A major challenge lies in achieving a balance among intermolecular interactions, structural stability, and responsiveness to external stimuli. In this study, we address this challenge by developing intrinsically healable and photoresponsive electrospun fabrics composed of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), thermoplastic polyurethane (TPU), and an azobenzene-based ionic liquid ([AzoC6MIM][TFSI]). The interactions between PVDF-HFP and [AzoC6MIM][TFSI] enable intrinsic self-healing and light-induced responsiveness, while the incorporation of TPU prevents fiber fusion during electrospinning, maintaining structural integrity and porosity. Our results demonstrate that these fabrics can recover up to 97% of their original mechanical properties after self-healing and exhibit reversible changes in electrical conductivity under UV and visible lights. This versatile approach paves the way for the incorporation of high concentrations of functional ionic liquids into electrospun fabrics, enabling the development of multifunctional textiles with potential applications in self-healing wearable devices and advanced sensors.

Recent Achievements in Heterogeneous Bimetallic Atomically Dispersed Catalysts for Zn-Air Batteries: A Minireview

Rechargeable Zn-air batteries (ZABs) hold promise as the next-generation energy-storage devices owing to their affordability, environmental friendliness, and safety. However, cathodic catalysts are easily inactivated in prolonged redox potential environments, resulting in inadequate energy efficiency and poor cycle stability. To address these challenges, anodic active sites require multiple-atom combinations, that is, ensembles of metals. Heterogeneous bimetallic atomically dispersed catalysts (HBADCs), consisting of heterogeneous isolated single atoms and atomic pairs, are expected to synergistically boost the cyclic oxygen reduction and evolution reactions of ZABs owing to their tuneable microenvironments. This minireview revisits recent achievements in HBADCs for ZABs. Coordination environment engineering and catalytic substrate structure optimization strategies are summarized to predict the innovation direction for HBADCs in ZAB performance enhancement. These HBADCs are divided into ferrous and nonferrous dual sites with unique microenvironments, including synergistic effects, ion modulation, electronic coupling, and catalytic activity. Finally, conclusions and perspectives relating to future challenges and potential opportunities are provided to optimise the performance of ZABs.

Adsorption and storage of hydrogen- A computational model approach

Due to the imperative global energy transition crisis, hydrogen storage and adsorption technologies are becoming popular with the growing hydrogen economy. Recently, complex hydrides have been one of the most reliable materials for storing and transporting hydrogen gas to various fuel cells to generate clean energy with zero carbon emissions. With the ever-increasing carbon emissions, it is necessary to substitute the current energy sources with green hydrogen-based efficient energy-integrated systems. Herein, we propose an input-output model that comprehends complex hydrides such as lithium and magnesium alanates, amides and borohydrides to predict, estimate, and directly analyse hydrogen storage and adsorption. A critical and thorough comparative analysis of the respective complex hydrides for hydrogen adsorption and storage is discussed, elucidating the storage applications in water bodies. Several industrial scale-up processes, economic analysis, and plant design of hydrogen storage and adsorption approaches are suggested through volumetric and gravimetric calculations.

Endogenous electric field coupling Mxene sponge for diabetic wound management: haemostatic, antibacterial, and healing

Improper management of diabetic wound effusion and disruption of the endogenous electric field can lead to passive healing of damaged tissue, affecting the process of tissue cascade repair. This study developed an extracellular matrix sponge scaffold (K1P6@Mxene) by incorporating Mxene into an acellular dermal stroma-hydroxypropyl chitosan interpenetrating network structure. This scaffold is designed to couple with the endogenous electric field and promote precise tissue remodelling in diabetic wounds. The fibrous structure of the sponge closely resembles that of a natural extracellular matrix, providing a conducive microenvironment for cells to adhere grow, and exchange oxygen. Additionally, the inclusion of Mxene enhances antibacterial activity(98.89%) and electrical conductivity within the scaffold. Simultaneously, K1P6@Mxene exhibits excellent water absorption (39 times) and porosity (91%). It actively interacts with the endogenous electric field to guide cell migration and growth on the wound surface upon absorbing wound exudate. In in vivo experiments, the K1P6@Mxene sponge reduced the inflammatory response in diabetic wounds, increased collagen deposition and arrangement, promoted microvascular regeneration, Facilitate expedited re-epithelialization of wounds, minimize scar formation, and accelerate the healing process of diabetic wounds by 7 days. Therefore, this extracellular matrix sponge scaffold, combined with an endogenous electric field, presents an appealing approach for the comprehensive repair of diabetic wounds.

Optimization Design of a Multi-String Standing Wave Electrospinning Apparatus Based on Electric Field Simulations

The mass production of uniform, high-quality polymer nanofibers remains a challenge. To enhance spinning yield, a multi-string standing wave electrospinning apparatus was developed by incorporating a string array into a standing wave electrospinning device. The process parameters such as string spacing, quantity, and phase difference were optimized, and their effects on the electric field distribution within the spinning area were analyzed using electric field simulations. When the string spacing was less than 40 mm or the number of strings exceeded two, the electric field strength significantly decreased due to electric field interference. However, this interference could be effectively mitigated by setting the string standing wave phase difference to half a period. The optimal string array parameters were identified as string spacing of 40 mm, two strings, and a phase difference of half a period. Multi-string standing wave electrospinning produced fibers with diameters similar to those obtained with single-string standing wave electrospinning (178 ± 72 nm vs. 173 ± 48 nm), but the yield increased by 88.7%, reaching 2.17 g/h, thereby demonstrating the potential for the large-scale production of nanofibers. This work further refined the standing wave electrospinning process and provided valuable insights for optimizing wire-type electrospinning processes.

Drug eluting protein and polysaccharides-based biofunctionalized fabric textiles- pioneering a new frontier in tissue engineering: An extensive review

In the ever-evolving landscape of tissue engineering, medicated biotextiles have emerged as a game-changer. These remarkable textiles have garnered significant attention for their ability to craft tissue scaffolds that closely mimic the properties of natural tissues. This comprehensive review delves into the realm of medicated protein and polysaccharide-based biotextiles, exploring a diverse array of fabric materials. We unravel the intricate web of fabrication methods, ranging from weft/warp knitting to plain/stain weaving and braiding, each lending its unique touch to the world of biotextiles creation. Fibre production techniques, such as melt spinning, wet/gel spinning, and multicomponent spinning, are demystified to shed light on the magic behind these ground-breaking textiles. The biotextiles thus crafted exhibit exceptional physical and chemical properties that hold immense promise in the field of tissue engineering (TE). Our review underscores the myriad applications of drug-eluting protein and polysaccharide-based textiles, including TE, tissue repair, regeneration, and wound healing. Additionally, we delve into commercially available products that harness the potential of medicated biotextiles, paving the way for a brighter future in healthcare and regenerative medicine. Step into the world of innovation with medicated biotextiles-where science meets the art of healing.

Recent Advancements of Bioinks for 3D Bioprinting of Human Tissues and Organs

3D bioprinting is recognized as a promising biomanufacturing technology that enables the reproducible and high-throughput production of tissues and organs through the deposition of different bioinks. Especially, bioinks based on loaded cells allow for immediate cellularity upon printing, providing opportunities for enhanced cell differentiation for organ manufacturing and regeneration. Thus, extensive applications have been found in the field of tissue engineering. The performance of the bioinks determines the functionality of the entire printed construct throughout the bioprinting process. It is generally expected that bioinks should support the encapsulated cells to achieve their respective cellular functions and withstand normal physiological pressure exerted on the printed constructs. The bioinks should also exhibit a suitable printability for precise deposition of the constructs. These characteristics are essential for the functional development of tissues and organs in bioprinting and are often achieved through the combination of different biomaterials. In this review, we have discussed the cutting-edge outstanding performance of different bioinks for printing various human tissues and organs in recent years. We have also examined the current status of 3D bioprinting and discussed its future prospects in relieving or curing human health problems.

Bioinspired Hierarchical Multi-Protective Membrane for Extreme Environments via Co-Electrospinning-Electrospray Strategy

Extreme environments can cause severe harm to human health, and even threaten life safety. Lightweight, breathable clothing with multi-protective functions would be of great application value. However, integrating multi-protective functions into nanofibers in a facile way remains a great challenge. Here, a one-step co-electrospinning-electrospray strategy is developed to fabricate a superhydrophobic multi-protective membrane (S-MPM). The water contact angle of S-MPM can reach up to 164.3°. More importantly, S-MPM can resist the skin temperature drop (11.2 °C) or increase (17.2 °C) caused by 0 °C cold or 70 °C hot compared with pure electrospun membrane. In the cold climate (-5 °C), the anti-icing time of the S-MPM is extended by 2.52 times, while the deicing time is only 1.45 s due to the great photothermal effect. In a fire disaster situation, the total heat release and peak heat release rate values of flame retarded S-MPM drop sharply by 24.2% and 69.3%, respectively. The S-MPM will serve as the last line of defense for the human body and has the potential to trigger a revolution in the practical application of next-generation functional clothing.

Hydroxyapatite: A journey from biomaterials to advanced functional materials

Hydroxyapatite (HAp), a well-known biomaterial, has witnessed a remarkable evolution over the years, transforming from a simple biocompatible substance to an advanced functional material with a wide range of applications. This abstract provides an overview of the significant advancements in the field of HAp and its journey towards becoming a multifunctional material. Initially recognized for its exceptional biocompatibility and bioactivity, HAp gained prominence in the field of bone tissue engineering and dental applications. Its ability to integrate with surrounding tissues, promote cellular adhesion, and facilitate osseointegration made it an ideal candidate for various biomedical implants and coatings. As the understanding of HAp grew, researchers explored its potential beyond traditional biomaterial applications. With advances in material synthesis and engineering, HAp began to exhibit unique properties that extended its utility to other disciplines. Researchers successfully tailored the composition, morphology, and surface characteristics of HAp, leading to enhanced mechanical strength, controlled drug release capabilities, and improved biodegradability. These modifications enabled the utilization of HAp in drug delivery systems, biosensors, tissue engineering scaffolds, and regenerative medicine applications. Moreover, the exceptional biomineralization properties of HAp allowed for the incorporation of functional ions and molecules during synthesis, leading to the development of bioactive coatings and composites with specific therapeutic functionalities. These functionalized HAp materials have demonstrated promising results in antimicrobial coatings, controlled release systems for growth factors and therapeutic agents, and even as catalysts in chemical reactions. In recent years, HAp nanoparticles and nanostructured materials have emerged as a focal point of research due to their unique physicochemical properties and potential for targeted drug delivery, imaging, and theranostic applications. The ability to manipulate the size, shape, and surface chemistry of HAp at the nanoscale has paved the way for innovative approaches in personalized medicine and regenerative therapies. This abstract highlights the exceptional evolution of HAp, from a traditional biomaterial to an advanced functional material. The exploration of novel synthesis methods, surface modifications, and nanoengineering techniques has expanded the horizon of HAp applications, enabling its integration into diverse fields ranging from biomedicine to catalysis. Additionally, this manuscript discusses the emerging prospects of HAp-based materials in photocatalysis, sensing, and energy storage, showcasing its potential as an advanced functional material beyond the realm of biomedical applications. As research in this field progresses, the future holds tremendous potential for HAp-based materials to revolutionize medical treatments and contribute to the advancement of science and technology.

Insights into non-crystalline structure of solid solution Ce-Mn co-oxide nanofibers for efficient low-temperature toluene oxidation

The controllable preparation of efficient non-crystalline solid solution catalysts is a great challenge in the catalytic oxidation of volatile organic compounds. In this work, series non-crystalline solid solution structured Ce-Mn co-oxide nanofibers were creatively prepared by adjusting Ce/Mn molar ratios using electrospinning. 0.20CeMnOx (the ratio of Ce to Mn was 0.2) displayed an outstanding low-temperature toluene oxidation activity (T90 = 233 °C). The formation of the amorphous solid solution and the unique nanofiber structure both contributed to a large specific surface area (S = 173 m2 g-1) and high adsorbed oxygen content (Oads/O = 41.3%), which enhanced the number of active oxygen vacancies. The synergies between non-crystalline structure and active oxygen species markedly improved oxygen migration rate as well as redox ability of the catalysts. Additionally, in situ diffuse reflectance infrared Fourier transform spectra showed that the absorbed toluene could be completely oxidized to CO2 and H2O with benzyl alcohol, benzaldehyde, benzoic acid, and maleic anhydride as intermediates. In summary, this study provided an alternative route for the synthesis of non-crystalline metal co-oxide nanofibers.

Progress on Improved Fouling Resistance-Nanofibrous Membrane for Membrane Distillation: A Mini-Review

Nanofibrous membranes for membrane distillation (MD) have demonstrated promising results in treating various water and wastewater streams. Significant progress has been made in recent decades because of the development of sophisticated membrane materials, such as superhydrophobic, omniphobic and Janus membranes. However, fouling and wetting remain crucial issues for long-term operation. This mini-review summarizes ideas as well as their limitations in understanding the fouling in membrane distillation, comprising organic, inorganic and biofouling. This review also provides progress in developing antifouling nanofibrous membranes for membrane distillation and ongoing modifications on nanofiber membranes for improved membrane distillation performance. Lastly, challenges and future ways to develop antifouling nanofiber membranes for MD application have been systematically elaborated. The present mini-review will interest scientists and engineers searching for the progress in MD development and its solutions to the MD fouling issues.

Electrospun Nanofiber-Based Bioinspired Artificial Skins for Healthcare Monitoring and Human-Machine Interaction

Artificial skin, also known as bioinspired electronic skin (e-skin), refers to intelligent wearable electronics that imitate the tactile sensory function of human skin and identify the detected changes in external information through different electrical signals. Flexible e-skin can achieve a wide range of functions such as accurate detection and identification of pressure, strain, and temperature, which has greatly extended their application potential in the field of healthcare monitoring and human-machine interaction (HMI). During recent years, the exploration and development of the design, construction, and performance of artificial skin has received extensive attention from researchers. With the advantages of high permeability, great ratio surface of area, and easy functional modification, electrospun nanofibers are suitable for the construction of electronic skin and further demonstrate broad application prospects in the fields of medical monitoring and HMI. Therefore, the critical review is provided to comprehensively summarize the recent advances in substrate materials, optimized fabrication techniques, response mechanisms, and related applications of the flexible electrospun nanofiber-based bio-inspired artificial skin. Finally, some current challenges and future prospects are outlined and discussed, and we hope that this review will help researchers to better understand the whole field and take it to the next level.

Preparation and Properties of (Sc2O3-MgO)/Pcl/Pvp Electrospun Nanofiber Membranes for the Inhibition of Escherichia coli Infections

Due to their high porosity, large specific surface area, and structural similarity with the extracellular matrix (ECM), electrospun nanofiber membranes are often endowed with the antibacterial properties for biomedical applications. The purpose of this study was to synthesize nano-structured Sc2O3-MgO by doping Sc³⁺, calcining at 600 °C, and then loading it onto the PCL/PVP substrates with electrospinning technology with the aim of developing new efficient antibacterial nanofiber membranes for tissue engineering. A scanning electron microscope (SEM) and energy dispersive X-ray spectrometer (EDS) were used to study the morphology of all formulations and analyze the types and contents of the elements, and an X-ray diffraction (XRD), thermogravimetric analysis (TGA), and Fourier transform attenuated total reflection infrared spectroscopy (ATR-FTIR) were used for further analysis. The experimental results showed that the PCL/PVP (SMCV-2.0) nanofibers loaded with 2.0 wt% Sc₂O₃-MgO were smooth and homogeneous with an average diameter of 252.6 nm; the antibacterial test indicated that a low load concentration of 2.0 wt% Sc2O3-MgO in PCL/PVP (SMCV-2.0) showed a 100% antibacterial rate against Escherichia coli (E. coli).

Polyurethane and cellulose acetate micro-nanofibers containing rosemary essential oil, and decorated with silver nanoparticles for wound healing application

In this study, polyurethane (PU) and cellulose acetate (CA) electrospun fibers encapsulating rosemary essential oil (REO) and adsorbed silver (Ag) nanoparticles (NPs) were fabricated. The biologically inspired materials were analyzed for physicochemical characteristics using scanning electron microscopy, X-ray diffractometer, Fourier transform infrared, thermal gravimetric analysis, X-ray photoelectron spectroscopy, water contact angle, and water uptake studies. Results confirmed the presence of CA and Ag NPs on the PU micro-nanofibers increased the hydrophilicity from 107.1 ± 0.36^o to 26.35 ± 1.06^o. The water absorption potential increased from 0.07 ± 0.04 for pristine PU fibers to 12.43 ± 0.49 % for fibers with 7 wt% of CA, REO, and Ag NPs. The diffractometer confirmed the 2θ of 38.01°, 44.13^o, and 64.33^o, corresponding to the diffraction planes of Ag on the fibers. The X-ray photoelectron spectroscopy confirmed microfibers interfacial chemical interaction and surface changes due to CA, REO, and Ag presence. The inhibition tests on Staphylococcus aureus and Escherichia coli indicated that composites are antibacterial in activity. Moreover, synergistic interactions of REO and Ag NPs resulted in superior antibacterial activity. The cell viability and attachment assay showed improved hydrophilicity of the fibers, which resulted in better attachment of cells to the micro-nanofibers, similar to the natural extracellular matrix in the human body.

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.

Structural design of the electrospun nanofibrous membrane for membrane distillation application: a review

Although membrane distillation (MD) is a promising technology for water desalination and industrial wastewater treatment, the MD process is not widely applied in the global water industry due to the lack of a suitable membrane for the MD process. The design and appropriate manufacture are the most important factors for MD membrane optimization. The well-designed porous structure, superhydrophobic surface, and pore-wetting prevention of the membrane are vital properties of the MD membrane. Nowadays, electrospinning that is capable of manufacturing membranes with superhydrophobic or omni phobic properties is considered a promising technology. Electrospun nanofibrous membranes (ENMs) possess the characteristics of cylindrical morphology, re-entrant structure, and easy-shaping for a specific purpose, benefiting the membrane design and modification. Based on that, this review investigates the current state and future progress of the superhydrophobic, multi-layer, and omniphobic ENMs manufactured with various structural designs for seawater desalination and wastewater purification. We expect that this paper will provide some recommendations and guidance for further fabrication research and the configuration design of ENMs in the MD process for seawater desalination and wastewater purification.

Nitrogen Self-Doping Carbon Derived from Functionalized Poly(Vinylidene Fluoride) (PVDF) for Supercapacitor and Adsorption Application

A new synthetic strategy has been developed for the facile fabrication of a N-doped porous carbon (NC-800) material via a facile carbonization of functionalized poly(vinylidene fluoride) (PVDF). The prepared NC-800 exhibits good specific capacitance of 205 F/g at 1 A/g and cycle stability (95.2% retention after 5000 cycles at 1 A/g). The adsorption capacity of NC-800 on methylene blue and methyl orange was 780 mg/g and 800 mg/g, respectively. The facile and economical method and good performance (supercapacitor and adsorption) suggest that the NC-800 is a promising material for energy storage and adsorption.

Recent Progress on Bimetallic-Based Spinels as Electrocatalysts for the Oxygen Evolution Reaction

Electrocatalytic water splitting is a promising and viable technology to produce clean, sustainable, and storable hydrogen as an energy carrier. However, to meet the ever-increasing global energy demand, it is imperative to develop high-performance non-precious metal-based electrocatalysts for the oxygen evolution reaction (OER), as the OER is considered the bottleneck for electrocatalytic water splitting. Spinels, in particular, are considered promising OER electrocatalysts due to their unique properties, precise structures, and compositions. Herein, the recent progress on the application of bimetallic-based spinels (AFe₂ O₄ , ACo₂ O₄ , and AMn₂ O₄ ; where A = Ni, Co, Cu, Mn, and Zn) as electrocatalysts for the OER is presented. The fundamental concepts of the OER are highlighted after which the family of spinels, their general formula, and classifications are introduced. This is followed by an overview of the various classifications of bimetallic-based spinels and their recent developments and applications as OER electrocatalysts, with special emphasis on enhancing strategies that have been formulated to improve the OER performance of these spinels. In conclusion, this review summarizes all studies mentioned therein and provides the challenges and future perspectives for bimetallic-based spinel OER electrocatalysts.

Novel Wet Electrospinning Inside a Reactive Pre-Ceramic Gel to Yield Advanced Nanofiber-Reinforced Geopolymer Composites

Electrospinning is a versatile approach to generate nanofibers in situ. Yet, recently, wet electrospinning has been introduced as a more efficient way to deposit isolated fibers inside bulk materials. In wet electrospinning, a liquid bath is adopted, instead of a solid collector, for fiber collection. However, despite several studies focused on wet electrospinning to yield polymer composites, few studies have investigated wet electrospinning to yield ceramic composites. In this paper, we propose a novel in-situ fabrication approach for nanofiber-reinforced ceramic composites based on an enhanced wet-electrospinning method. Our method uses electrospinning to draw polymer nanofibers directly into a reactive pre-ceramic gel, which is later activated to yield advanced nanofiber-reinforced ceramic composites. We demonstrate our method by investigating wet electrospun Polyacrylonitrile and Poly(ethylene oxide) fiber-reinforced geopolymer composites, with fiber weight fractions in the range 0.1–1.0 wt%. Wet electrospinning preserves the amorphous structure of geopolymer while changing the molecular arrangement. Wet electrospinning leads to an increase in both the fraction of mesopores and the overall porosity of geopolymer composites. The indentation modulus is in the range 6.76–8.90 GPa and the fracture toughness is in the range 0.49–0.76 MPam with a clear stiffening and toughening effect observed for Poly(ethylene oxide)-reinforced geopolymer composites. This work demonstrates the viability of wet electrospinning to fabricate multifunctional nanofiber-reinforced composites.

The design and synthesis of spinel one-dimensional multi-shelled nanostructures for Li-ion batteries

The rational design, synthesis, and massive production of one-dimensional (1D) spinel composite oxides with multi-shelled nanostructures are critical for the realization of highly efficient energy conversion and storage. However, owing to the limitations of the synthetic methods, the 1D multi-shelled nanostructures, especially for multi-element oxides and binary-metal oxides, have been rarely fabricated. Herein, we design a facile and general method to fabricate 1D spinel composite oxides with complex architectures. It is found that the concentration of the precursor polymer PAN can control the structures of the products at optimal heating rate, including hollow nanofibers, wire-in-tube nanofibers, and tube-in-tube nanofibers. This technique could be extended to various inorganic multi-element oxides and binary-metal oxides. Moreover, numerous twin boundaries (TBs) are found to form in the Co_0.5Ni_0.5Fe₂O₄ tube-in-tube nanofibers. Benefiting from both large porosity and TBs structures, the tube-in-tube hollow nanostructures are measured to possess superior electrochemical performances with high energy and stability in lithium-ion storage.

Electrospun Donor/Acceptor Nanofibers for Efficient Photocatalytic Hydrogen Evolution

We prepared a series of one-dimensional conjugated-material-based nanofibers with different morphologies and donor/acceptor (D/A) compositions by electrospinning for efficient photocatalytic hydrogen evolution. It was found that homogeneous D/A heterojunction nanofibers can be obtained by electrospinning, and the donor/acceptor ratio can be easily controlled. Compared with the single-component-based nanofibers, the D/A-based nanofibers showed a 34-fold increase in photocatalytic efficiency, attributed to the enhanced exciton dissociation in the nanofibrillar body. In addition, the photocatalytic activity of these nanofibers can be easily optimized by modulating the diameter. The results show that the diameter of the nanofibers can be conveniently controlled by the electrospinning feed rate, and the photocatalytic effect increases with decreasing fiber diameter. Consequently, the nanofibers with the smallest diameter exhibit the most efficient photocatalytic hydrogen evolution, with the highest release rate of 24.38 mmol/(gh). This work provides preliminary evidence of the advantages of the electrospinning strategy in the construction of D/A nanofibers with controlled morphology and donor/acceptor composition, enabling efficient hydrogen evolution.

A Multifunctional Janus Electrospun Nanofiber Dressing with Biofluid Draining, Monitoring, and Antibacterial Properties for Wound Healing

Wound healing greatly affects patients' health and produces medical burden. Therefore, we developed a multifunctional electrospun nanofiber dressing, which can inhibit methicillin-resistant Staphylococcus aureus (MRSA), drain excessive biofluid to promote wound healing, and simultaneously monitor wound pH level. The polyoxometalate (α-K₆P₂W₁₈O₆₂·14H₂O, P₂W₁₈) and oxacillin (OXA) are encapsulated in hydrophobic polylactide (PLA) nanofiber to synergistically inhibit MRSA. The phenol red (PSP) is encapsulated in hydrophilic polyacrylonitrile (PAN) nanofiber to sensitively indicate wound pH in situ. The PSP/PAN nanofiber is directly electrospun on the patterning OXA/P₂W₁₈/PLA nanofiber layer to form a Janus dressing. By taking advantage of the wettability difference between the two layers, the excess biofluid can be drained away from the wound. In addition, the Janus dressing exhibits good biocompatibility and accelerates wound healing via its antimicrobial activity and skin repairing function. This multifunctional Janus electrospun nanofiber dressing would be beneficial for wound management and treatment.

Gravity-driven electrospun membranes for effective removal of perfluoro-organics from synthetic groundwater

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are emerging contaminants in water and soil. Electrospun membranes with open structure could treat PFAS in a gravity-driven mode with ultralow pressure needs. The electrospun ultrathin fibers (67 ± 27 nm) was prepared for the enhanced specific surface area; where polyvinylidene fluoride (PVDF) backbones and the grafted quaternary ammonium moieties (QA; PVDF-g-QA membranes) provided both hydrophobicity and anion-exchange ability (electrostatic interaction). High affinity towards the perfluorooctanoic acid (PFOA)/perfluorooctanesulfonic acid (PFOS) molecules (denoted as PFOX collectively) was observed, and >95% PFOX was removed from synthetic groundwater with a flux of 32.3 Lm-2h-1 at ΔPo = 313 Pa. With a higher octanol/water partitioning coefficient (Log Kow = 6.3) and close dispersion interaction parameter to the membrane backbones (16.6% difference in δd), the effective PFOS removal remained under alkaline and high conductivity conditions due to the intensive hydrophobic interaction compared to that of PFOA. Long-term studies exhibited >90% PFOX removal in an 8 h test with a capacity of 258 L/m2. Under mild regeneration conditions, PFOA and PFOS were concentrated by 35-fold and 39-fold, respectively. Overall, the gravity-driven electrospun PVDF-g-QA membranes, with adsorptive effectiveness and ease of regeneration, showed great potential in PFAS remediation.

A review on Biopolymer-derived Electrospun Nanofibers for Biomedical and Antiviral Applications

Unique aspects of polymer-derived nanofibers provide significant potential in the area of biomedical and health care applications. Much research has demonstrated several plausible nanofibers to overcome the modern-day challenges in...

Strategies for Developing Transition Metal Phosphides in Electrochemical Water Splitting

Electrochemical water splitting involving hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is a greatly promising technology to generate sustainable and renewable energy resources, which relies on the exploration regarding the design of electrocatalysts with high efficiency, high stability, and low cost. Transition metal phosphides (TMPs), as nonprecious metallic electrocatalysts, have been extensively investigated and proved to be high-efficient electrocatalysts in both HER and OER. In this minireview, a general overview of recent progress in developing high-performance TMP electrocatalysts for electrochemical water splitting has been presented. Design strategies including composition engineering by element doping, hybridization, and tuning the molar ratio, structure engineering by porous structures, nanoarray structures, and amorphous structures, and surface/interface engineering by tuning surface wetting states, facet control, and novel substrate are summarized. Key scientific problems and prospective research directions are also briefly discussed.

Skin protein-derived peptide-conjugated vesicular nanocargos for selected skin cell targeting and consequent activation

Several studies have reported that a drug nanocarrier conjugated with ligands having cell binding ability improves drug delivery performance, but multiple cell-targeting and the resultant activation in designated cells has not been investigated yet. This study reports a skin cell multi-targeting vesicular nanocargo system. We selectively conjugated several skin protein-derived cell-targeting peptides (CTPs), including KTTKS, NAP-amide, and Lam332, to amphiphilic polymer-reinforced lipid nanovesicles (PLNVs) to specifically target fibroblasts, melanocytes, and keratinocytes, respectively, through effective association with the corresponding cell membrane receptors. We then showed that CTP-conjugated PLNVs specifically bind to the designated skin cells, even in a mixture of different types of skin cells, eventually leading to skin cell multi-targeting and consequent activation. These results highlight that this CTP-conjugated PLNV system has significant potential for developing an intelligent cellular drug delivery technology for dermatological applications.

Recent advances in PLGA-based biomaterials for bone tissue regeneration

Bone regeneration is an interdisciplinary complex lesson, including but not limited to materials science, biomechanics, immunology, and biology. Having witnessed impressive progress in the past decades in the development of bone substitutes; however, it must be said that the most suitable biomaterial for bone regeneration remains an area of intense debate. Since its discovery, poly (lactic-co-glycolic acid) (PLGA) has been widely used in bone tissue engineering due to its good biocompatibility and adjustable biodegradability. This review systematically covers the past and the most recent advances in developing PLGA-based bone regeneration materials. Taking the different application forms of PLGA-based materials as the starting point, we describe each form's specific application and its corresponding advantages and disadvantages with many examples. We focus on the progress of electrospun nanofibrous scaffolds, three-dimensional (3D) printed scaffolds, microspheres/nanoparticles, hydrogels, multiphasic scaffolds, and stents prepared by other traditional and emerging methods. Finally, we briefly discuss the current limitations and future directions of PLGA-based bone repair materials. STATEMENT OF SIGNIFICANCE: As a key synthetic biopolymer in bone tissue engineering application, the progress of PLGA-based bone substitute is impressive. In this review, we summarized the past and the most recent advances in the development of PLGA-based bone regeneration materials. According to the typical application forms and corresponding crafts of PLGA-based substitutes, we described the development of electrospinning nanofibrous scaffolds, 3D printed scaffolds, microspheres/nanoparticles, hydrogels, multiphasic scaffolds and scaffolds fabricated by other manufacturing process. Finally, we briefly discussed the current limitations and proposed the newly strategy for the design and fabrication of PLGA-based bone materials or devices.

Transition metal sulfides meet electrospinning: versatile synthesis, distinct properties and prospective applications

One-dimensional (1D) electrospun nanomaterials have attracted significant attention due to their unique structures and outstanding chemical and physical properties such as large specific surface area, distinct electronic and mass transport, and mechanical flexibility. Over the past years, the integration of metal sulfides with electrospun nanomaterials has emerged as an exciting research topic owing to the synergistic effects between the two components, leading to novel and interesting properties in energy, optics and catalysis research fields for example. In this review, we focus on the recent development of the preparation of electrospun nanomaterials integrated with functional metal sulfides with distinct nanostructures. These functional materials have been prepared via two efficient strategies, namely direct electrospinning and post-synthesis modification of electrospun nanomaterials. In this review, we systematically present the chemical and physical properties of the electrospun nanomaterials integrated with metal sulfides and their application in electronic and optoelectronic devices, sensing, catalysis, energy conversion and storage, thermal shielding, adsorption and separation, and biomedical technology. Additionally, challenges and further research opportunities in the preparation and application of these novel functional materials are also discussed.

Composite Poly(vinyl alcohol)-Based Nanofibers Embedding Differently-Shaped Gold Nanoparticles: Preparation and Characterization

Poly(vinyl alcohol) nanofibrous mats containing ad hoc synthesized gold nanostructures were prepared via a single-step electrospinning procedure and investigated as a novel composite platform with several potential applications. Specifically, the effect of differently shaped and sized gold nanostructures on the resulting mat physical-chemical properties was investigated. In detail, nearly spherical nanoparticles and nanorods were first synthesized through a chemical reduction of gold precursors in water by using (hexadecyl)trimethylammonium bromide as the stabilizing agent. These nanostructures were then dispersed in poly(vinyl alcohol) aqueous solutions to prepare nanofibrous mats, which were then stabilized via a humble thermal treatment able to enhance their thermal stability and water resistance. Remarkably, the nanostructure type was proven to influence the mesh morphology, with the small spherical nanoparticles and the large nanorods leading to thinner well defined or bigger defect-rich nanofibers, respectively. Finally, the good mechanical properties shown by the prepared composite mats suggest their ease of handleability thereby opening new perspective applications.

A self-boosting microwave plasma strategy tuned by air pressure for the highly efficient and controllable surface modification of carbon

Surface modification is required to improve the activity and compositing ability of carbonaceous materials for their application in numerous areas such as energy storage, aerospace applications, and construction reinforcement. However, current strategies are facing problems such as the involvement of expensive and corrosive chemicals, poor controllability, and breakage of the carbon skeleton, thus sacrificing the mechanical and electrical properties. In this study, a green and controllable self-boosting microwave technology is proposed for the high-efficient surface modification of carbon. Air was used as the only oxidant. A carbon fiber cloth (CFC) is exposed to microwave irradiation in air for 90 s, yielding CFC with a surface oxygen content of 25.73%, 54.41%, and 52.56% at 1 atm, 8000 Pa, and 80 Pa, respectively, as determined via X-ray photoelectron spectroscopy. Notably, the content of each oxygen-containing functional group (e.g., -C-OH and -C[double bond, length as m-dash]O) is controllable by tuning the air pressure. Besides, CFC has enhanced mechanical and electrical properties. In comparison, CFC treated with a strong acid for 2 h only has a surface oxygen content of 21.4%, exhibiting greatly impaired electrical and mechanical properties. Numerical simulations at different pressures suggest that air plasma is triggered and boosted by the existence of CFC at 8000 Pa and 80 Pa, generating different electron number densities and electron temperature distributions, thus resulting in high-efficient and controllable modification.

Systematic Review of Silk Scaffolds in Musculoskeletal Tissue Engineering Applications in the Recent Decade

During the past decade, various novel tissue engineering (TE) strategies have been developed to maintain, repair, and restore the biomechanical functions of the musculoskeletal system. Silk fibroins are natural polymers with numerous advantageous properties such as good biocompatibility, high mechanical strength, and low degradation rate and are increasingly being recognized as a scaffolding material of choice in musculoskeletal TE applications. This current systematic review examines and summarizes the latest research on silk scaffolds in musculoskeletal TE applications within the past decade. Scientific databases searched include PubMed, Web of Science, Medline, Cochrane library, and Embase. The following keywords and search terms were used: musculoskeletal, tendon, ligament, intervertebral disc, muscle, cartilage, bone, silk, and tissue engineering. Our Review was limited to articles on musculoskeletal TE, which were published in English from 2010 to September 2019. The eligibility of the articles was assessed by two reviewers according to prespecified inclusion and exclusion criteria, after which an independent reviewer performed data extraction and a second independent reviewer validated the data obtained. A total of 1120 articles were reviewed from the databases. According to inclusion and exclusion criteria, 480 articles were considered as relevant for the purpose of this systematic review. Tissue engineering is an effective modality for repairing or replacing injured or damaged tissues and organs with artificial materials. This Review is intended to reveal the research status of silk-based scaffolds in the musculoskeletal system within the recent decade. In addition, a comprehensive translational research route for silk biomaterial from bench to bedside is described in this Review.

Mechanical and Dielectric Properties of Aligned Electrospun Fibers

This review paper examines the current state-of-the-art in fabrication of aligned fibers via electrospinning techniques and the effects of these techniques on the mechanical and dielectric properties of electrospun fibers. Molecular orientation, system configuration to align fibers, and post-drawing treatment, like hot/cold drawing process, contribute to better specific strength and specific stiffness properties of nanofibers. The authors suggest that these improved, aligned nanofibers, when applied in composites, have better mechanical and dielectric properties for many structural and multifunctional applications, including advanced aerospace applications and energy storage devices. For these applications, most fiber alignment electrospinning research has focused on either mechanical property improvement or dielectric property improvement alone, but not both simultaneously. Relative to many other nanofiber formation techniques, the electrospinning technique exhibits superior nanofiber formation when considering cost and manufacturing complexity for many situations. Even though the dielectric property of pure nanofiber mat may not be of general interest, the analysis of the combined effect of mechanical and dielectric properties is relevant to the present analysis of improved and aligned nanofibers. A plethora of nanofibers, in particular, polyacrylonitrile (PAN) electrospun nanofibers, are discussed for their mechanical and dielectric properties. In addition, other types of electrospun nanofibers are explored for their mechanical and dielectric properties. An exploratory study by the author demonstrates the relationship between mechanical and dielectric properties for specimens obtained from a rotating mandrel horizontal setup.

Glutaraldehyde cross-linked CDA/HBP-NH2 nanofiber membrane for adsorption of heavy metal ions in wastewater

A new type of nanofiber membrane was prepared by mixed electrospinning of cellulose diacetate and amino-terminated hyperbranched polymer (HBP-NH₂), and glutaraldehyde (GA) crosslinking was used to improve its water resistance and shape retention. pH, adsorption time, and initial solution concentration on Cu(ii) and Cr(vi) ions were studied. Results showed that the prepared GA-CDA/HBP-NH₂ nanofiber had good spinning uniformity, hydrophilicity, and adsorption effect on Cu(ii) and Cr(vi) ions compared with the pure CDA nanofiber. The maximum adsorption capacity of GA-CDA/HBP-NH₂ for Cu(ii) and Cr(vi) was 50.2 and 176.6 mg g⁻¹, respectively.

A new type of nanofiber membrane was prepared by mixed electrospinning of cellulose diacetate and amino-terminated hyperbranched polymer (HBP-NH₂), and glutaraldehyde (GA) crosslinking was used to improve its water resistance and shape retention.

Electrospun carbon nanofibers embedded with MOF-derived N-doped porous carbon and ZnO quantum dots for asymmetric flexible supercapacitors

Hierarchical carbon nanofibers are embedded with MOF-derived N-doped porous carbon nanoparticles and decorated with ZnO quantum dots via a co-spinning method.