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Cell sheets combined with electrospun fibrous mats represent an attractive approach for the repair and regeneration of injured tissues. However, the conventional dense electrospun mats as supportive substrates in forming "cell sheet on fiber mat" complexes suffer from problems of limiting the cellular function and eliciting a host response upon implantation. To give full play to the role of electrospun biomimicking fibers in forming quality cell sheets, this study proposed to develop a cell-fiber integrated sheet (CFIS) featuring a spatially homogeneous distribution of cells within the fiber structure by using a low-density fibrous network for cell sheet formation. A low-density electrospun polycaprolactone (PCL) fibrous network at a density of 103.8 ± 16.3 μg cm

Burns are usually difficult to treat because their susceptibe to bacterial infections. When burns is accompanied by hyperthermia, the heat accumulated on the skin will causes extensive tissue damage. Most dressings focus on the treatment process, while ignoring the first-aid treatment to remove hyperthermia. To make matters worse, when outdoors, it is hard to find clean water to wash and cool the burned area. A dressing which can simultaneously realize first-time cooling and repairing treatment of the burned area can shorten treatment time, and is especially beneficial for outdoor use. In this study, a handheld coaxial electrospinning device is developed for preparing platelet-rich plasma @Polycaprolactone-epsilon polylysine (PRP@PCL/ε-PL) core-shell nanofibers. The nanofibers can be synchronously transformed into ice fibers during the spinning process, and directly deposited on the skin. The whole process is convenient to use outdoor. Via dual cooling mechanisms, first aid can take away the excessive heat in the burn area by nanofibers. These core-shell nanofibers also show its excellent antimicrobial and tissue regeneration-promoting properties. Therefore, it achieves first-time cooling and repair treatment of the burned area at the same time. Moreover, due to direct in-situ deposition of this handheld coaxial electrospinning, better antimicrobial properties, and faster healing performance are achieved. By using this integrated strategy that combines cooling, antibacterial and healing promotion, the burn recovery time is shortened from 21 days to 14 days.

The corrosion of materials severely limits the application scenarios of triboelectric nanogenerators (TENGs), especially in laboratories, chemical plants and other fields where leakage of chemically corrosive solutions is common.

Crustaceans and fish scales in the marine food industry are basically thrown away as waste. This not only wastes resources but also causes environmental pollution. While reducing pollution and waste, biological activity and storage of materials are urgent issues to be solved. In this study, by first preparing dry fibers and then making hydrogels, we prepared a fish scale/sodium alginate/chitosan nanofiber hydrogel (FS-P) by cross-linking the nanofibers

Magnetic materials are of increasing importance for many essential applications due to their unique magnetic properties. However, due to the limited fabrication ability, magnetic materials are restricted by simple geometric shapes. Three-dimensional (3D) printing is a highly versatile technique that can be utilized for constructing magnetic materials. The shape flexibility of magnets unleashes opportunities for magnetic composites with reducing post-manufacturing costs, motivating the review on 3D printing of magnetic materials. This paper focuses on recent achievements of magnetic materials using 3D printing technologies, followed by the characterization of their magnetic properties, which are further enhanced by modification. Interestingly, the corresponding properties depend on the intrinsic nature of starting materials, 3D printing processing parameters, and the optimized structural design. More emphasis is placed on the functional applications of 3D-printed magnetic materials in different fields. Lastly, the current challenges and future opportunities are also addressed.

A review of recent advances in electrospun magnetic nanofibers and their applications

It is a challenge to achieve flexibility in purely inorganic piezoelectric materials without organic support, and various thin film flexible inorganic piezoelectric materials has been developed recently. In this work, lead zirconate titanate (PZT) nanofiber membranes were prepared by electrospinning, and a flexible membranes can be obtained by reducing the calcination temperature, and the flexibility was characterized by the three-point method. The fiber membrane was relatively thicker in relative to thin films and confirmed to adsorb Congo Red quickly under the action of ultrasound. The maximum adsorption capacity is 61.78 mg g−1 and saturation time reaches 20 min under ultrasound treatment. In addition, the color change after saturation adsorption can quickly determine the actual load of the fiber membrane. In the future, this load saturation effect can be used to calibrate the relationship between the piezoelectric signal and the adsorption load, so as to obtain more accurate chemical sensors.

Traditional inorganic materials exhibit rigidity owing to the lack of polymer chains in polymer materials or atom slipping in metals. However, nanometerization has been recently proposed for the conversion of inorganic oxide materials into flexible materials. Herein, the flexible inorganic luminescent material, CaTiO3:0.2%Pr3+, was synthesized through electrospinning, and the macroscopic flexibility of pure inorganic CaTiO3:0.2%Pr3+ was achieved. The flexible membrane was characterized via X-ray diffraction, thermogravimetry, scanning electron microscopy (SEM), and photoluminescence analyses. The grain size was analyzed at various calcination temperatures via SEM, and the results suggested that the increase in the calcination temperature resulted in the growth of crystal grains. Studies have reported that the growth of crystal grains is beneficial for improving the luminescence performance; however, to obtain better flexibility, smaller crystal grains are required. This study provides an important reference for the design of flexible inorganic materials.

Bacterial infections prolong the wound healing time and increase the suffering of patients, thus it is important to develop wound dressing that can inhibit bacterial infection. Herein, we use two methods including “doping method” and “secondary growth method” to prepare ZIF-8@gentamicin embedded in and coated on polyacrylonitrile/gelatin (PG) nanofibers, separately. Composite nanofibers prepared by the secondary growth method achieve higher drug loading than that of the doping method, and the release rate can be adjusted by pH. Simultaneously increasing drug loading and regulating its release rate are achieved in the secondary growth method, which cannot be achieved by the doping method. Furthermore, synergistic antibacterial property occurs in the composite nanofibers prepared by the secondary growth method, and gentamicin loaded on ZIF-8 promotes the antibacterial effect, which shows better antibacterial effect than the doping method. As a result, during the wound infection of mouse, composite nanofibers prepared by the secondary growth method exhibit a faster recovery effect than the doping method, which effectively shortened the wound healing time from 21 days to 16 days.

High sensitivity of sensors is extremely significant for precisely monitoring imperceptible changes of motion in real-time, which cannot be achieved by traditional piezoelectric devices. Herein, a hierarchical polyvinylidene fluoride hexafluoropropylene (PVDF-HFP)/ZnO composite nanaofiber piezoelectric sensor with highly sensitivity has been prepared through epitaxial growing ZnO nanosheets on the surface of electrospun PVDF-HFP nanofibers. Systematic investigations have shown that their optimum pressure sensing performance with a sensitivity of 1.9 V kPa−1 and a short response time of 20 ms are achieved for forces from 0.02 to 0.5 N with excellent durability and stability up to 5000 cycles. Moreover, this sensor can precisely detect the imperceptible changes in player’s motions to avoid injury from overtraining. Additionally, a Bluetooth-low-energy that tracks player’s workout and transmits the output signals wirelessly to a smartphone app is utilized. The study provides a feasible approach for high-precision detecting and safety monitoring in the fields of medical, rehabilitation medicine, and workout security.

In spite of the excellent electrochemical performance in lithium-ion batteries (LIBs), transition-metal compounds usually show inferior capacity and cyclability in sodium-ion batteries (SIBs), implying different reaction schemes between these two types of systems. Herein, coupling operando magnetometry with electrochemical measurement, we peformed a comprehensive investigation on the intrinsic relationship between the ion-embedding mechanisms and the electrochemical properties of the typical FeS2/Na (Li) cells. Operando magnetometry together with ex-situ transmission electron microscopy (TEM) measurement reveal that only part of FeS2 is involved in the conversion reaction process, while the unreactive parts form "inactive cores" that lead to the low capacity. Through quantification with Langevin fitting, we further show that the size of the iron grains produced by the conversion reaction are much smaller in SIBs than that in LIBs, which may lead to more serious pulverization, thereby resulting in worse cycle performance. The underlying reason for the above two above phenomena in SIBs is the sluggish kinetics caused by the larger Na-ion radius. Our work paves a new way for the investigation of novel SIB materials with high capacity and long durability.

As the critical component of proton exchange membrane fuel cell (PEMFC), proton exchange membrane (PEM) determine its overall performance. Current PEMs hardly meet the operating requirements of fuel cells, limiting their commercial applications. With the development of nanocomposite technology, nanofibers introduced into PEMs to prepare nanofiber composite proton exchange membranes (NCPEMs) have been widely studied. In an NCPEM, nanofibers can form long-range channels for proton transport, and reinforced skeleton to reach the target performance of PEMFCs. Focusing on NCPEM, this paper reviews on recent progresses in nanofiber preparation and NCPEM preparation techniques. Furthermore, different types of nanofibers incorporated into NCPEMs are reviewed in terms of fiber composition. The challenges and future perspectives regarding NCPEMs are also discussed.

Oil leakage has posed serious threat to the environment, but still remain a great challenge to be solved especially for harsh environmental conditions. Herein, robust superhydrophobic nickel hydroxide grown by hydrothermal method and stearic acid modification on a blow-spun polyacrylonitrile (PAN)/Al

With the continuous development of science and technology, smart sensing wearables have gradually entered people’s lives. However, the prepared wearable material has poor air permeability, poor fit, and does not have multiple modal excitations. In addition, it is not waterproof or even wearable at low temperatures. In this work, a thermoplastic polyurethane (TPU) and ZnS:Al composite film with excellent air permeability has been developed. The TPU/ZnS:Al flexible film can be prepared on a large scale by solution blow spinning (SBS). This fiber membrane can realize the dual response of temperature and stress, and cooperate with the light sensor to realize the transmission of intelligent information. This nanofiber membrane doped with ZnS:Al exhibits a uniform distribution, maintains excellent tensile properties and flexibility, and can adapt to any perfect shape of the fitting surface. Even the average air permeability can be as high as 300 mm s−1, which is 600 times that of conventional spraying methods. The Al introduced in ZnS:Al can stimulate the composite film to emit light, and the luminescence effect can be maintained for about 1 min. These results provide new ideas for the large-scale fabrication of integrated stimulus-responsive photosensitive intelligent wearable devices for various applications.

The cleanup of oily wastewater and crude-oil spills is a global challenge. Traditional membrane materials are inefficient for oil/water separation under harsh conditions and limited by sorption speeds because of the high viscosity of crude oil. Herein, a kind of Graphene-wrapped polyphenylene sulfide fibrous membrane with superior chemical resistance and hydrophobicity for efficient oil/water separation and fast adsorption of crude oil all-weather is reported. The reduced graphene oxide (rGO)@polyphenylene sulfide (PPS) fibrous membrane can be applied in the various harsh conditions with Joule heating and solar heating. In addition, the oil(dichloromethane)/water separation flux of rGO@PPS reached 12 903 L m-2h-1, and the separation efficiency reached 99.99%. After 10 cycles, the rGO@PPS still performed high separation flux and filtration efficiency. More importantly, the rGO@PPS still retained its high conductivity, excellent filtration efficiency, and stable hydrophobicity after acid or alkali treatment. Moreover, the rGO@PPS can be heated by solar energy to absorb viscous crude oil during the day, while at night, the crude oil can be adsorbed by Joule heating. The time to adsorb crude oil can be reduced by 98.6% and 97.3% through Joule heating and solar heating, respectively. This all-weather utilization greatly increases the adsorption efficiency and effectively reduces energy consumption.

Under the limitation of the carrier yield and mobility of semiconductor photocatalysts and the reaction domain, it seems that the photocatalytic efficiency cannot be greatly improved. Here, an efficient contact-electro-catalysis (CEC) system based on droplet triboelectric nanogenerator (TENG) is developed. Instead of using traditional semiconductor catalysts, the electric charge transferred during the electrification process of the contact between water droplets and polytetrafluoroethylene (PTFE) is used to participate in catalysis, and the output electrical signal can also monitor the degree of catalysis. The important role of light in the circulation of this CEC system is studied and discussed for the first time. It is proved that the contact electrification at the liquid-solid interface is accompanied by the generation of a large number of strong oxidizing radicals. The efficient transport of charge carriers driven by mechanical force and the active oxygen species distributed in the whole domain greatly improve the degradation rate of dyes. The experimental data show that the degradation efficiency of crystal violet (CV) reaches 90% within 38 s, and the rate constant k is as high as 3.7 min

Burns and scalds are thermal injuries caused by a large amount of heat accumulation in local tissues. The first cooling emergency is a key step. However, it is hard that in outdoors to find clean water to cool the scald tissue sites. Moreover, most dressings are concentrated on the treatment process today, neglecting the emergency treatment of temperature reduction. In this study, we imported refrigeration in the electrospinning process while using dirty water, rainwater and even urine of outdoors, so that the cooled sterile fibers were directly deposited on the burn and scald wounds, and the cooling emergency was achieved through the dual cooling mechanism. Since this fiber which is made up of cheap fish gelatin contains CuS adopting the green method, it can generate heat and effectively kill bacteria under the irradiation of an illumination lamp at the front end of a spinning device. As a result of the direct deposition, there is an excellent fit between the fibrous membrane and the skin, which reduces the air gap to achieve a better and quick cooling and heating effects. On the same Chitosan/Platelet-derived Growth Factor fiber membrane, this method of cooling first and heating second can shorten the recovery time from 30 days to 21 days. Thus, this treatment strategy has a great potential application prospect in the field of outdoor burn treatment.

The weft-knitted reduced graphene oxide (r-GO) textile that is made up of many conductive r-GO coated fibers was successfully prepared dependent on the electrospray deposition technique. Interestingly, the r-GO textile presents negative resistance variation not only in axial direction as the pressure increases but also in transverse direction as the lateral stretch increases which makes it has the advantage to fabricate the reliable sensors based on strain-resistance effect. The transverse-strain and pressure sensors based on the r-GO textiles all show the excellent sensing characteristics such as high sensitivity, reliability, and good durability, etc. The maximum gauge factors (GF) of the transverse-sensor are 27.1 and 153.5 in the x- and y-direction, respectively. And the practical detection range can up to 40% in the x-direction and 35% in the y-direction, respectively. The r-GO textile pressure sensor also shows high sensitivity for a broad pressure range that with a GF up to 716.8 kPa−1 for less than 4.5 kPa region and still has more sensitive pressure sensing characteristics even the pressure goes up to 14 kPa. Based on those good performances of r-GO textile sensors, its potential applications in human body states monitoring have been studied.

Piezoelectric catalysis is an emerging research field in recent years. Since the catalytic reaction usually occurs on the surface, the specific surface area is very important for piezoelectric catalysis. Therefore, nanoparticles and nanowires have been developed for piezoelectric catalysis and have attracted widespread attention. However, in actual water applications, the use of nanoparticles will cause secondary pollution. Therefore, an overall deformable nanoporous system is urgently needed to adapt to the shapes of various ultrasonic transducer heads. We have obtained macroscopically inorganic flexible barium titanate nanofiber membranes through electrospinning technology. Without traditional organic mixtures, the surface of the piezoelectric material can fully come into contact with water. The fiber membrane is macroscopically integrated, deformable, and can fully adapt to multiple ultrasonic transducers of various shapes. Calcium doping can effectively improve the catalytic effect, and the catalytic rate (k × 103) of the material with the highest doping concentration can reach 24.47 min−1. In addition, studies have found that lowering the calcination temperature can effectively improve the flexibility of the fiber membrane, which can be attributed to smaller barium titanate grains formed at low temperature. This work provides a generic method for preparing flexible inorganic piezoelectric materials that can be adapted to a variety of surfaces, and successfully applies it in the field of piezoelectric catalysis, which provides an important way for the practical research of piezoelectric catalysis in the future.

Manganese dioxide (MnO2) promises for high-performance asymmetric suprecapacitors, owing to its high theoretical capacity, abundant source, and low cost. However, insufficient practically-achievable capacity and relatively narrow voltage window in alkaline electrolyte are blocking high energy density of MnO2-based supercapacitors, where strategies for activating its capacitive performance and widening voltage window are the top priorities to solve the bottleneck problems. Herein, both the fiber-in-tube (NCCM-FiT) and particle-in-tube (NCCM-PiT) nanostructures coulping active NiCoOx nanoparticles and conductive carbon with MnO2 tubes have been purposely fabricated, using the electrospun nickel cobalt oxides/carbon nanofibers (NCO/CNFs) as the self-template agents for enhanced energy density of MnO2-based supercapacitors. These hierarchical hollow nanotubes with gradient pores and unique compositions yield excellent capacitive properties, in terms of a competitive capacity (431.7 F g−1 or 431.7 C g−1, 0.5 A g−1), which is 2.7 times that of the MnO2 nanotubes-based electrodes. A maximum energy density of 46.4 Wh kg−1 is obtained at the power density of 400 W kg−1 for the asymmetric device assembled with the NCCM-PiT-based positive electrode and the electrospun CNFs-based negative electrode. The remarkable energy density demonstrated by these hierarchical hollow nanotubes exemplifies a novel and effective design in electrode materials for the asymmetric supercapacitors (ASCs) with superior performance.

In the past 30 years, researchers have worked towards reducing the size of ordinary three-dimensional (3D) materials into 1D or 2D materials in order to obtain new properties and applications of these low-dimensional systems. Among them, functional nanofibers with large surface area and high porosity have been widely studied and paid attention to. Because of the interesting properties of nanofibers, they find extensive application in filtration, wound dressings, composites, sensors, capacitors, nanogenerators, etc. Recently, a variety of nanofiber preparation methods such as melt blowing, electrospinning (e-spinning), centrifugal spinning and solution blow spinning (SBS) have been proposed. This paper includes a brief review of the fundamental principles of the preparation of nanofibers for solution jet spinning, the influence of experimental parameters, and the properties and potential applications of the solution-blown fibers. And the industrialization and challenges of SBS are also included.

Conventional encryptions including single and multiple encryptions still have disadvantages, such as low security, complicated operation process and time consuming. Herein, a dual information encryption mechanism based on the exclusivity of the decryption process is proposed, which uses carbon dots (CDs) as fluorescent inks with two rounds of encryption and decryption to perform dual information encryption. The encryption process is easy to operate, and the decryption process can be completed in a short time (