Janus membrane with opposite wettability on its two sides has witnessed an explosion of interest in the field of liquid spontaneous and directional transport for their promising prospect. The advances in fabrication technology and natural bionics have brought remarkable progress for the development of Janus materials. Among the exciting progress, the micro/nanofabrication technique of electrospinning shows advantages in constructing thin porous fibrous membrane materials with controllable surface wettability and hierarchical structures. Here, a brief review of bioinspired Janus membrane for unidirectional liquid penetration fabricated by electrospinning is presented, and the underlying scientific mechanism is discussed with an emphasis on the materials design involving asymmetric surface wettability and micro-topology structure. An overview of recent emerging applications is also reviewed, with special attentions to liquid separation, water collection, distillation, and smart textile, etc. As researchers keep to develop more efficient strategies on designing new Janus membrane with higher performances, it has become increasingly important to understand the mechanism of liquid moving dynamics at the asymmetric interface in order to better recognize the scientific limitations currently hindering the field development. At last, the challenges currently faced and possible strategies on developing new Janus membranes for optimization and engineering in the future are proposed.

Functional nanofibrous membranes fabricated by electrospinning technology have attracted much attention in the removal of heavy metal ions from contaminated wastewater. The high specific surface area, high porosity and ease of functionality create an enhanced throughput and high adsorption capacity of the nanofibrous membrane. However, the relatively poor mechanical properties of the membrane with a non-woven nanofibrous structure are one of the major concerns, which can limit the applications in wastewater treatment. Different strategies and methodologies were explored to address the problems and were reviewed in this work, highlighting the possibilities of overcoming the poor mechanical properties of the nanofibrous membrane and to ensure the recyclability and reusability of the membrane during the adsorption process.

Ultrathin oxide nanofibers are widely used in an array of catalytic applications toward energy conversion and environmental protection. Remarkable progress has been made with regard to the development of engineering oxide nanofibers into unique structures to suit or enable various functions. We aim to provide a comprehensive overview of oxide nanofibers, including the structure engineering, derivates, assemblies and their applications. We begin with a brief introduction to the production of nanofibers with diversified compositions, structures and properties, followed by discussions of the wet-chemistry derivates. Afterward, we discuss the applications of catalytic oxide nanofibers, including electrocatalysis, photocatalysis and thermal-catalysis. Then we highlight the most significant role of oxide nanofibers as catalyst support for the immobilization of metal nanoparticles. Moreover, we showcase the advanced assemblies based on oxide nanofibers, including their use as multi-functional membranes and foams. In the end, we offer perspectives on the challenges, opportunities and new directions for future development.

Electrospinning with a simple and controllable process has extremely received considerable concerns by virtue of the fabrication and development of nanofibers. Moreover, nanofibers are playing an increasing impact on energy conversion and storage devices, especially for fuel cells based on oxygen reduction reaction(ORR), in view of the rich porosity, large surface area, excellent mass transportation and simply tunable composition, as well as good mechanical strength. In this review, we mainly introduce the primary principle of electrospinning technique, electrochemical reaction mechanism of ORR and synthetic strategies, and summarize the recent advances of unique non-noble-metal nanofibers on the basis of metal-organic framework(MOF) derivatives, single-atom catalysts(SACs) and transition metal oxides. More importantly, we emphasize on the influences of the components, morphology and architecture of advanced electrospun catalysts on their corresponding electrochemical performances towards ORR. Finally, the remaining puzzles and perspectives for further development of the electrospinning nanofibers involving electrocatalysis are presented. It is envisioned that this review would offer an important direction in designing novel electrocatalysts based on electrospinning nanofibrous structures and developing their potential.

Cardiovascular diseases have been the leading cause of morbidity and mortality in the world recently. With the growing aging population accompanied by chronic diseases, such as uremia and diabetes, there is an increasing clinical demand for vascular grafts with proper performance. Although some achievements have been made in the development of tissue-engineered vascular grafts composed of natural and synthetic polymeric materials or decellularized vessels, clinical applications with a diameter of less than 6 mm are still principally derived from autografts, such as autologous saphenous veins. Many challenges remain in antithrombosis, rapid endothelialization, modulating the inflammatory response and inhibition of intimal hyperplasia and calcification. In the review, recent progress in the electrospinning of biodegradable polymers for vascular regeneration are summarized, especially from the view of biomechanical factors. Hybrid vascular grafts consisting of natural and synthetic polymers with multicomponent, di- or tri-layers are focused in order to provide novel experiences in biomaterials for applications in this field.

Patients with spinal cord injury(SCI) are suffering disability and accompanying complications. Due to the complex biological processes and inhibitory microenvironment after SCI, advances in clinical treatment show obvious limitations for achieving a successful repair. Herein, we summarize recent advances in engineering strategies of using electrospun nanofibers to promote the neural regeneration and functional recovery after SCI. We firstly introduce the pathological mechanism of SCI and thus point out the challenges on the regeneration of the nerve. We then discuss the regenerative approaches by combining electrospun nanofibrous scaffolds with physical cues, biochemical cues(e.g., cells, growth factors and other biomolecules), external stimuli, and supporting materials filling in the inner lumen of the scaffolds. All these strategies have indicated their potentials to enhance the efficacy of repairing the SCI. At last, we provide a perspective on the future direction for designing the electrospun nanofibrous scaffolds in combination with imaging systems to realize the in-situ monitoring of regeneration progress for further improving the treatment outcome.

The alum-borneol nanoemulsion(ABN), which combines the mineral medicine alum and the botanical medicine borneol, has been applied for approximately 40 years in the clinical treatment of burns, scalds, radiation dermatitis and shingles, and has a good curative effect. However, the current formula and dosage form of ABN pose problems of low borneol content and ease of precipitation, which greatly affects the efficacy of the drug. In this study, polyvinylpyrrolidone(PVP) was selected as a carrier mixed with different proportions of alum and borneol to produce alum-borneol-PVP fibers(ABPF) by electrospinning. The results showed that the stable system with good drug dispersion was 2:3(alum:borneol). The dissolution content of borneol from the ABPF was about 80% in 4 h, which was much higher than that of the alum-borneol liquid(ABL) and ABN. The ABPF membrane showed a more significant inhibitory effect on Staphylococcus aureus than the ABL and ABN. The composite fiber markedly increased the drug content of borneol, which was 800 times of that in ABN. The fiber had a higher solubility than the nanoemulsion in vitro, which is of great importance for the development of new forms for the clinical application of alum and borneol.

A composite photocatalyst, with branch-like BiOI/Bi₂WO₆ heterojunction deposited on the polyacrylonitrile micro/nano composite fiber(PAN MNCF), was prepared via two step hydrothermal method. The products are characterized by X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), photoluminescence(PL) spectra, UV-Vis diffuse reflection spectroscopy(UV-Vis DRS) and time-resolved fluorescence spectra. The PAN/BiOI/Bi₂WO₆ micro/nano composite fiber(PAN/BiOI/Bi₂WO₆ MNCF) showed better visible-light photocatalytic performance than PAN MNCF or BiOI/Bi₂WO₆ powder, probably ascribed to the collective effect between PAN MNCF and BiOI/Bi₂WO₆ heterojunction. Significantly, the PAN/BiOI/Bi₂WO6 MNCF could be easily recycled through filtration method, thus avoiding the secondary pollution.

Low density and high porosity polyacrylonitrile(PAN) nanofibers prepared by electrospinning were used as brackets for photocatalyst W₁₈O₄₉ to prepare a kind of light weight and easy recycling water purification material for the first time. The influence of tungsten source concentration on the formation of W₁₈O₄₉ during a solvothermal process was systematically investigated. The prepared PAN@W₁₈O₄₉ nanofibers(NFs) utilize the outstanding visible light photocatalytic performance and the adsorption performance of W₁₈O₄₉, and at the same time give the advantages of low density and easy recyclability. The pollutant removal performance of the composite nanofibers was investigated by using five contaminants including rhodamine B(RhB), methylene blue(MB), malachite green(MG), methyl orange(MO) and chlortetracycline(CTC) as substrates. Among them, the degradation process of rhodamine B has been studied in detail. After five cycles, the degradation efficiency did not decrease significantly, showing excellent reusability of PAN@W₁₈O₄₉ NFs. Besides, the adsorption performance of PAN@W₁₈O₄₉ NFs during the photocatalytic process was also studied in detail. Compared with recently reported literature, the degradation efficiency of organic pollutants by PAN@W₁₈O₄₉ NFs showed better performance, and PAN@W₁₈O₄₉ NFs felt had a promising prospect in the field of degradation of contaminants.

Electrospinning and calcination technique have been combined to fabricate N-doped carbon nanofibers(N-CNFs) by introducing amino grafted few-layered hexagonal boron nitride (amino@BN) into polyacrylonitrile(PAN) matrix as filler followed by carbonization. For the high N-doping level(10.7%, atomic fraction) with the final product, the as-prepared N-CNFs exhibit interesting surface wettability(superamphiphilicity in air and underwater oleophilicity). Moreover, compared with pristine PAN derived carbon nanofibers(marked as CNFs), N-CNFs exhibit higher graphic structure under fixed carbonizing temperature as well. Taking these advantages aforementioned, the as-prepared N-CNFs exhibit good specific capacitance(ca. 200.1 F/g) without activation treatment at the current density of 0.5 A/g in three-electrode configuration, which is about 149% that of CNFs(ca. 134 F/g). What’s more, our N-CNFs also display the unexpected capacity to demulsify diverse surfactant free oil-in-water emulsions by simple filtration in large scale with the high water flux ca.(23578±150) L·m⁻²·h⁻¹

Both electrospinning apparatus and their commercial products are extending their applications in a wide variety of fields. However, very limited reports can be found about how to implement an energy-saving process and in turn to reduce the production cost. In this paper, a brand-new type of coaxial spinneret with a solid core and its electrospinning methods are developed. A novel sort of medicated Eudragit/lipid hybrid nanofibers are generated for providing a colon-targeted sustained release of aspirin. A series of characterizations demonstrates that the as-prepared hybrid nanofibers have a fine linear morphology with the aspirin/lipid separated from the matrix Eudragit to form many tiny islands. In vitro dissolution tests exhibit that the hybrid nanofibers are able to effectively prevent the release of aspirin under an acid condition (8.7%±3.4% for the first two hours), whereas prolong the drug release time period under a neutral condition(99.7±4.2% at the seventh hour). The energy-saving mechanism is discussed in detail. The prepared aspirin-loaded hybrid nanofibers can be further transferred into an oral dosage form for potential application in countering COVID-19 in the future.

Gallic acid(GA) is a kind of natural polyphenolic compound, but its low aqueous solubility restricts its application in the fields of food and medicine. Cyclodextrin can form inclusion complexes with guest molecules(e.g., essential oils, food supplements) through cavities with special properties to improve aqueous solubility, thermal stability, and bioavailability of guest molecules. In this research, gallic acid/2-hydroxypropyl-β-cyclodextrin inclusion complexes(GA/2-HP-β-CD/ICs) were formed in a highly concentrated solution of 2-HP-β-CD. Bead-free and uniform nanofibrous webs(GA/2-HP-β-CD/IC-NWs) were produced successfully by electrospun GA/HP-β-CD/IC aqueous solution. The initial molar ratio(GA: 2-HP-β-CD=1:1) of GA/2-HP-β-CD/IC in the solutions was largely maintained in GA/2-HP-β-CD/IC-NW. The aqueous solubility of GA was enhanced and GA/2-HP-β-CD/IC-NW has displayed fast dissolution property. Furthermore, in comparison with GA powder, GA/2-HP-β-CD/IC-NW demonstrated improved antioxidant capacity. The results suggested that GA/2-HP-β-CD/IC-NW have broad application prospects as orally fast dissolution systems for food supplements.

Electrospun nanofibers are of the same length scale as the native extracellular matrix and have been extensively reported to facilitate adhesion and proliferation of cells and to promote tissue repair and regeneration. With a primary focus on tissue repair and regeneration using electrospun scaffolds, only a few studies involved electrospun nanofiber scaffolds directing cell behaviors have been reported. In this study, we prepared electrospun nanofiber scaffolds with distinct fiber configurations, namely, random and aligned orientations of nanofibers, as well as oriented yarns, and investigated their effects on cell behaviors. Our results showed that these scaffolds supported good proliferation and viability of murine fibroblasts. Fiber configuration profoundly influenced cell morphology and orientation but showed no effects on cell proliferation rate. The yarn scaffold had comparable total protein accumulation with the random and aligned scaffolds, but it supported a greater proliferation rate of fibroblasts with significantly elevated collagen deposition due to its porous fibrous configuration. Cell-seeded yarn scaffolds showed a greater Young’s modulus compared with cell-free controls as early as 1 week. Together with its unique fiber configuration similar to the native extracellular matrix of the myocardium, the yarn scaffold might be a suitable matrix material for modeling cardiac fibrotic disorders.

Antibacterial wound dressing can benefit the wound healing by preventing bacterial infection, especially for the electrospun ones due to their porous structures and easily loading antibacterial drugs. However, it is challenging to apply the antibacterial electrospun wound dressing to covering the wound conveniently and safely. Here, we presented one step fabrication and application of antibacterial electrospun zein/cinnamon oil wound dressing via a handheld electrospinning setup. The prepared zein/cinnamon oil wound dressing showed gas permeability of (76.1–5.45) mm/s, hydrophilicity with zero body fluid contact angle, swelling stability after 24 h as well as antibacterial zones over 5 cm against both E. coli and S. aureus bacteria. Moreover, in situ electrospinning process can deposit the electrospun zein/cinnamon oil fibers directly onto the wound, meantime forming a wound dressing. The mice cut-wound model experiment demonstrated that the one step in situ fabrication and application of zein/cinnamon oil wound dressing could nearly heal the wound within 11 d.

Water flux and hydrophobic durability play important roles in membrane distillation(MD) applications. Compared with the method of adsorbing nanoparticles by electrostatic adsorption, the surface roughness constructed by chemical bonding is more conducive to the performance of membrane. This paper reports a facile approach to fabricating superhydrophobic fluoroalkyl silane/polydimethylsiloxane@FeOOH@stabilized polyacrylonitrile(FAS/PDMS@FeOOH@SPAN) nanofibrous membrane(NFM) with outstanding hierarchical structures, aiming to achieve efficient and stable performance in MD. Electrospun polyacrylonitrile(PAN) membrane after peroxidation was chosen as the base membrane, followed by in-situ synthesis of iron oxyhydroxide and liquid-phase silanization. We tested the characteristics of FAS/PDMS@FeOOH@SPAN NFM in each preparation stage and its performance in direct contact membrane distillation(DCMD). The chemical bond between iron oxyhydroxide and the membrane is stronger, making the rough structure steady and dense. The FAS/PDMS@FeOOH@SPAN NFM exhibited a water contact angle of 155.4° and excellent hydrophobicity towards different pollutants. Besides, it showed satisfied properties with a water flux of 24.7 L·m⁻²·h⁻¹, a high salts rejection of ca. 100% and an extended-term stability in DCMD using hypersaline water(10%, mass ratio). It is believed that this novel study proposes a universal and efficient method to fabricate a superhydrophobic surface and has great potential for high-salinity wastewater treatment in MD.

To reduce the cost of manufacture, it is urgent to develop efficient and stable platinum(Pt)-free counter electrode(CEs) electrocatalysts for dye-sensitized solar cells(DSSCs). In this study, a simple electrospinning and carbonization strategy has been developed to synthesize carbon nanofibers(CNFs) loaded with Ni and Mo₂C nanoparticles(Ni/Mo₂C/CNFs) as CE. Owing to the high electrical conductivity of CNFs and the large catalytic activity of Ni and Mo₂C, an excellent electrochemical performance of Ni/Mo₂C/CNFs as CE is achieved. The optimized DSSC assembled with Ni/Mo₂C(2:1)/CNFs-based CE exhibits a power conversion efficiency(PCE) of 8.90%, which exceeds the corresponding values of the device using the Pt(8.07%), Ni/Mo₂C(1:1)/CNFs(8.68%), Ni/Mo₂C(1:2)/CNFs(8.20%), Ni/CNFs(7.50%) and Mo₂C/CNFs(6.10%). This work provides a new strategy for developing effective and low-cost CE materials in DSSCs.

Transdermal drug delivery system(TDDS) facilitates the controlled release of active ingredients penetrating through the skin, avoiding the liver first pass effect. Electrospinning is a simple process to fabricate ultrafine fibers with a higher specific surface area, making them excellent candidates for drug delivery. In current work, a novel silk fibroin(SF) nanofiber loaded with cationic ethosomes(CEs) was prepared via green electrospinning. The data of Fourier transform infrared spectroscopy(FTIR) and laser scanning confocal microscopy(LSCM) confirmed the existence of CEs in the SF nanofibers. The morphology of the nanofibers was not significantly affected by the incorporation of CEs as shown by scanning electron microscopy(SEM) images. The CEs-loaded SF nanofibrous patch (CEs-SFnP) showed good cytocompatibility as proved by both cell counting Kit-8(CCK-8) assay and SEM. Using doxorubicin hydrochloride(Dox) as a model drug, the transdermal performance of CEs-SFnP was evaluated through Franz diffusion cell against mouse skin. The results indicated that CEs-SFnP can effectively deliver drug into the skin, with a much higher permeation rate than the normal nanofibers without CEs. The as-spun CEs-SFnP in this study could find promising applications in TDDS.

Lead ion(Pb²⁺) is one of the most hazardous heavy metal ions in aquatic environments. Carbon materials and manganese dioxide(MnO₂) have been shown to be prospective adsorbents to cope with the lead pollution. In this study, a novel hollow carbon@MnO₂ composite nanofiber adsorbent was prepared by the combination of electrospinning and carbonization. The PAN nanofiber membrane is subjected to a pre-oxidation and carbonization process, and then the obtained carbon nanofibers react with KMnO₄ solution during the hydrothermal process to develop the hollow carbon@MnO₂ nanofibers. The hollow carbon@MnO₂ nanofibers displayed a higher adsorption capacity of Pb²⁺ than carbon and MnO₂/PDA/PAN nanofibers. The maximum adsorption capacity toward Pb²⁺ by hollow carbon@MnO₂ nanofibers was 460.83 mg/g. After 5 adsorption-desorption cycles, the carbon@MnO₂ nanofibers had a good recyclability and the removal efficiency remained 81.47%. Moreover, the removal efficiency of the hollow composite nanofibers for Pb²⁺ from real wastewater could reach 94.37%. This work shows a strategy for synthetics of the hollow carbon@MnO₂ nanofibers, which exhibits a promising potential in actual wastewater treatment.

To enhance the mechanical and antibacterial properties of silver nanoparticle impregnated cellulosic fibers, carboxy-cellulose nanocrystals(CCNs) were grafted with chitooligosaccharide(COS), which was used as a stabilizer for silver nanoparticles (AgNPs). Nanofibrous membranes reinforced with silver nanoparticle impregnated cellulosic fibers(CCN-COS-AgNP) were prepared via electrospinning using polyvinyl alcohol(PVA) as a matrix. The effects of CCN-COS-AgNP contents on the morphology, surface composition, mechanical properties, and antibacterial performances of the prepared CCN-COS-AgNP/PVA membranes were examined. The addition of CCN-COS-AgNP certainly improved the mechanical properties and antibacterial performances of the PVA nanofibers. The tensile strength was significantly increased from 4.40 MPa to 8.60 MPa when 8% CCN-COS-AgNP(mass ratio) was introduced. When 10%(mass ratio) CCN-COS-AgNP was added, the nanofibers showed an excellent antibacterial activity for S. aureus(Staphylococcus aureus) and E. coli(Escherichia coli), with the maximum inhibition zones of 2.30 and 1.60 cm, respectively. Moreover, the 2%(mass ratio) CCN-COS-AgNP/PVA fibrous membrane showed 126% cell viability for mg63 human osteoblasts. The electrospun PVA membrane has great potential application in biomedical field.

In view of the current living micro-environment and requirements of green economy, intelligent light-responsive humidification materials have become a hot spot in intelligent polymer materials. In this work, reversible photoresponsive films with a mechanical stability and an excellent humidity adjustment performance are developed by modifying epoxy-ether-spiropyran(EPESP) on amino-nanofibers(PAN-NH₂), which was produced through electrospinning. Such smart films for regulating wettability and micro-environment humidity can be reversibly manipulated by the simple switch of UV and visible light irradiation because of the unique transformation between polar ring-opened status and nonpolar ring-closed status of the spiropyran units. The effects of EPESP modification amount on the morphology, wettability, tensile strength and the ability to regulate humidity were investigated in detail. The results show that with the increase of modification amount of EPESP, both the humidity regulation and tensile strength increased; when the modification amount exceeds 7 mg, the range of regulating humidity increases slowly.

We report a general strategy to develop injectable welded nanofibers to facilitate the outgrowth and extension of neurites. In this case, nonwoven mats of uniaxially aligned poly(caprolactone)(PCL) nanofibers were firstly cut into several small pieces with fixed fiber lengths of 25, 50 and 100 µm, respectively, using a cryotome. A tissuelyser was employed to homogenize and disperse the short nanofibers to a homogeneous suspension. By tuning treatment duration from 100 s to 400 s, the temperature of the suspension was brought close to the melting point of PCL. As such, the short nanofibers were welded at their cross points while the fibers far away from the cross points remain the original structures. We showed that the viability of neuroblastoma SH-SY5Y cells and their neurite outgrowth and extension were enhanced with the use of such welded short nanofibers. Taken together, this study provides a simple way to generate injectable welded nanofibers, holding potential in affecting neurite outgrowth and extension for nerve repair, in particular, in the central nervous system.

Micro-size oil adsorbents are effective for the rapid remediation of special oil spills. Here, N-doped reduced graphene oxide(RGO) microspheres(ca. 150 µm in diameter) with a local radially aligned and porous structure are fabricated by combining electrospray-freeze-drying with thermal treatment for rapid separation of oil-water. Owing to its hydrophobic/oleophilic properties and oriented structure, the N-doped RGO microspheres achieve high capacities and fast adsorption rates for a variety of oils and organic solvents. Furthermore, excellent oil-water separation performance on floating oil/oil-water emulsions and stable cyclic adsorption capacities are obtained for the local radially aligned and porous microsphere. Therefore, N-doped RGO microspheres with the unique porous structure have the potential for the remediation of oily sewage and oil spills.

Based on the functional properties of electrospun cellulose nanofibers(CNF), scientists are showing substantial interest to enhance the aesthetic properties. However, the lower color yield has remained a big challenge due to the higher surface area of nanofibers. In this study, we attempted to improve the color yield properties of CNF by the pad-steam dyeing method. Neat CNF was obtained by deacetylation of electrospun cellulose acetate(CA) nanofibers. Three different kinds of reactive dyes were used and pad-steam dyeing parameters were optimized. SEM images revealed smooth morphology with an increase in the average diameter of nanofibers. FTIR results showed no change in the chemical structure after dyeing of CNF. Color fastness results demonstrated excellent ratings for reactive dyes, which indicate good dye fixation properties and no color loss during the washing process. The results confirm that the pad-steam dyeing method can be potentially considered to improve the aesthetic properties of CNF, which can be utilized for functional garments, such as breathable raincoats and disposable face masks.

Carbon-black-modified carbon nanofibers were prepared by electrospinning, and the effects of the carbon black content and processing temperature on the physical and chemical properties of the resulting composites were investigated. The results showed that the conductivity of carbon-black-modified nanofibers increased with the carbon black content. The addition of carbon black in a 20% mass ratio increased the conductivity of the composite(0.75 S/cm) by 230% compared with the undoped nano-fiber(2.47 S/cm), while the adulteration with 5% CB allowed the preservation of the mechanical properties of the composites. The fabricated carbon-black/carbon-nanocomposite fibers exhibited excellent oil absorption and electrothermal conversion performance. Furthermore, the conductivity and oil absorption capacity increased with increasing carbonization temperature. With a carbonization temperature of 1000 °C(5% carbon black), the voltage was 31 V, the current was 0.66 A, and the surface temperature of the composite reached 234.1 °C. The overall enhancement in physical properties upon the addition of even low amounts of carbon black makes these composites advantageous for future industrial applications.

Multi-functional nanofibers are playing an important role in the optical field, and are widely used in fluorescence indication, product anti-counterfeit identification and smart clothing. Nanofibers with photoluminescence and photochromic functions are already attracting more interest from researchers. In this work, based on electrospun technology, the modified-PMMA nanofibers[PMMA=poly(methyl methacrylate)] with photoluminescence and photochromic functions were prepared through the design of the sheath-core structure(SCNFs 1–4). Compared with other samples, SCNF-4 shows outstanding photoluminescence and photochromic functions. SCNF-4 can produce green light and its fluorescence intensity and fluorescence lifetime can reach 7144 a.u. and 1031.32 µs, respectively. In photochromic functions, SCNF-4 can show purple in 1 min under the 365 nm ultraviolet light, and the color can be preserved for more than 4 h under the sunlight. When SCNF-4 is irradiated by far infrared light, the color of the samples can fade quickly in 40 s. Under the irradiation of ultraviolet light of different wavelengths, SCNF-4 can display multi-color fluorescence and achieve a reversible transition between white and purple. The design of the sheath-core structure realizes the complementarity of photoluminescence and photochromic functions of the electrospun modified-PMMA nanofibers, which is important to promote the wide application of multi-functional nanofibers in the optical field.

Encouraged by the porous and stable structure of cold-resist animals’ hair or feather, bio-inspired hierarchical structure yarns combining polyacrylonitrile(PAN) nanofibers and polypropylene(PP) hollow microfibers have been developed by a modified conjugate electrospinning technology. Physical cross-linking has been built to increase fibers adhesion and construct interlayer support for nanofibrous assembly. The nanofibers and hollow microfibers construct a stable porous structure with porosity of 62%, providing excellent thermal insulating ability[temperature difference(|ΔT|) between skin and yarn surface is 4.9 °C] as well as good mechanical property. More interestingly, the water transfer ability (infiltrate the yarn in 10 s) of synthetic fibers has been improved greatly by the combination of thin diameter nanofibers to the yarn. It is believed that the research lays the foundation for bio-inspired engineering technology in the manufacture of thermal comfort.

Ce/ZnO decorated carbon nanofibers(CNFs) heteroarchitectures(Ce/ZnO/CNFs) have been synthesized using electrospinning technique followed hydrothermal method, which have a high visible light photocatalytic activity. The samples were characterized by means of SEM, FTIR and XRD. The photocatalytic performance of Ce/ZnO/CNFs was tested with the methylene blue in the presence of visible light irradiation. In this work, we have analyzed the effects of Ce doping amount, initial methylene blue(MB) concentration and dosage of Ce/ZnO/CNFs on photocatalytic efficiency of the composite. The results showed that the photocatalyst containing 1.0% Ce in molarity(CZC1) obtained by autoclaving at 150 °C has the best photocatalytic degradation of MB than other as-synthesized samples. Ce/ZnO/CNFs catalysts exhibit a good stability and reusability, which would be an economical and environmentally friendly photocatalyst for various practical applications.

Convenient and integration fabrication process is a key issue for the application of functional nanofibers. A surface functionalization method was developed based on coaxial electrospinning to produce ultraviolet(UV) protection nanofibers. The titanium dioxide(TiO₂) nanoparticles suspension was delivered through the shell channel of the coaxial spinneret, by which the aggregation of TiO₂ nanoparticles was overcome and the distribution uniformity on the surface of polyethylene oxide(PEO) nanofiber was obtained. With the content of TiO₂ increasing from 0 to 3%(mass fraction), the average diameter of nanofibers increased from (380± 30) nm to (480±100) nm. The surface functionalization can be realized during the electrospinning process to gain PEO/TiO₂ composite nanofibers directly. The uniform distribution of TiO₂ nanoparticles on the surface of nanofibers enhanced the UV absorption and resistance performance. The maximum UV protection factor(UPF) value of composite nanofibers reaches 2751. This work presented a novel surface-functionalized way for the preparation of composite nanofiber, which has great application potential in the field of micro/nano system integration fabrication.

In this study, orthogonal experiments were designed to explore the optimal process parameters for preparing polycaprolactone(PCL) scaffolds by the near-field direct-writing melt electrospinning(NFDWMES) technology. Based on the optimal process parameters, the PCL scaffolds with different thicknesses, gaps and structures were manufactured and the corresponding hydrophilicities were characterized. The PCL scaffolds were modified by chitosan (CS) and hyaluronic acid(HA) to improve biocompatibility and hydrophilicity. Both Fourier transform infrared spectroscopy(FTIR) analysis and antibacterial experimental results show that the chitosan and hyaluronic acid adhere to the surface of PCL scaffolds, suggesting that the modification plays a positive role in biocompatibility and antibacterial effect. The PCL scaffolds were then employed as a carrier to culture cells. The morphology and distribution of the cells observed by a fluorescence microscope demonstrate that the modified PCL scaffolds have good biocompatibility, and the porous structure of the scaffolds is conducive to adhesion and deep growth of cells.

Partial P-type metal ions doping(PPMID) is an alternative method to further enhance the gas sensing performance of N-type metal oxides(NMOs) in contrast to that of P-N metal oxides heterojunctions, but the influences of the introduction of PPMID on the grain size and oxygen vacancies of NMOs have been rarely investigated. Herein, a simple and effective route has been demonstrated to address this problem with Cu²⁺-doped SnO₂ metastable solid solution nanofibers(CSMSSNs) as model and C₂H₂ as target molecule by combining electrospinning and calcination technique. It seems that the introduction of PPMID can also affect crystal structure and oxygen vacancies of NMOs, proven by combining X-ray diffraction(XRD) and X-ray photoelectron spectra(XPS). Thus, PPD, crystal structure and oxygen vacancies have been combined to clarify the enhanced sensing performance of Cu-doped SnO₂ metastable solid solution nanofibers angainst C₂H₂.

Stent graft(SG), isolating the diseased vessels from the normal blood circulation and preventing the rupture of the aneurysm wall in minimally invasive surgery, is normally composed of a metallic stent and a cover with a textile structure. In this study, the electrospinning method was used to prepare a new type of cover, and the preparing conditions and the performance of the SG were investigated. The polytetrafluoroethylene(PTFE) and polyethylene oxide(PEO) were blended at the ratios of 99:1, 98:2, 97:3 and electrospun to form precursor membranes. Then they were dried in a vacuum and sintered at different temperatures under different time periods to obtain PTFE membrane, which was compounded with a stent. Their morphology, mechanical properties, water permeability and biological properties were studied. The results showed that when the membrane was sintered at 380 °C for 10 min, it had the best tensile properties. The integral water permeability of the PTFE electrospun SG was close to 0. The hemolysis rate of the SG was 2.84%, and human umbillical vein endothelial cells(HUVECs) can adhere and proliferate well on the surface of the PTFE membranes. The PTFE electrospun SG had great potential for clinical application and industrialization.

The research of photo-responsive materials, with changed absorption and emission under light stimulus, has drawn more and more attention due to their wide applications. However, most of them suffered from the notorious aggregation-caused quenching(ACQ) effect, which often led to the unconspicuous luminescent change in photo-responsive process. To solve this problem, the strategy of combining aggregation-induced emission(AIE) and photochromic properties was utilized, which largely enriched the phenomenon and application of photo-responsive materials. This short review summarized the recent progress of photo-responsive AIE materials with changed UV absorbance or PL phenomenon under UV-irradiation, including the types of molecular structures, internal mechanisms and the practical applications. Also, some outlooks were given on the further exploration of this field at the end of this paper.

Low water vapor and air permeability is a persistent challenge in wearable and on-skin electronics, as it reduces wearing comfort, and leads to skin irritation and inflammation in the long term. To tackle this issue, Zheng and coworkers designed a stretchable conductor based on an elastomeric fiber mat coated by liquid metal. After simple activation via stretching, the flexible conductor was endowed with excellent permeability, good stretchability, exceptional electrical stability, and good biocompatibility, ascribed to the mesh-like structure and the vertically buckled structure of the liquid metal. Based on the intriguing properties of the material, it was employed in a multi-functional wearable device, able to detect the heartbeat and sweat while serving as a heating device. The corresponding research has been published in Nature Materials and can be accessed at https://doi.org/10.1038/s41563-020-00902-3.

Electrochemistry at confinement plays a significant impact on single entity analysis, efficient energy conversion, and nanofluidic transportation. Usually, the confinement is constructed by nanopore-structured materials. However, the physicochemical properties of function elements at inner walls of nanopore are inexplicit due to the limit of technology, which hinders the elegant modifications of nanopores and their related sophisticated applications. To address this issue, Xia and coworkers from China University of Geosciences developed a new solid-state nanochannel system modified with only function elements at outer surface. Explicit regulation of ion transport across this system was realized by the precise measurement of the physicochemical properties of function elements at the outer surface, which was further supported by the numerical simulations. Furthermore, this novel system shows advantages in osmotic energy conversion and universal sensing of targets from ions to cells. The corresponding research has been published in Nature Communications and can be accessed at https://doi.org/10.1038/s41467-021-21507-7.

Rapid classification of the secondary structures of nucleic acids, such as G-quadruplexes(G4s) is desirable but very challenging due to the high similarity among different folding. Chen et al. constructed a host-guest sensor array to differentiate the topology of unmodified G4s for the first time. Multiple equilibria present in the sensing system resulted in differential fluorescence responses to different G4 structures, and yielded excellent selectivity of the sensor array in structure discrimination. The corresponding research has been published in Nature Chemistry and can be accessed at https://doi.org/10.1038/s41557-021-00647-9.

Acute kidney injury is one of the most troublesome and lethal adverse effects in patients receiving chemotherapy. Conventional approaches that mitigate the toxicity of chemotherapeutic agents, however, also consequently compromise their tumorkilling efficacy. In order to overcome this dilemma, Ling and colleagues developed a ceria nanoparticle-based antioxidant agent that selectively relieved chemotherapy-induced oxidative damage in healthy tissues but not in the tumor microenvironment, where the slightly acidic pH acted to inhibit its enzyme-like and antioxidant activity. These ceria nanoparticles with context-dependent catalytic activity thus implied a possible reconciliation between effective protection from kidney injury and high potency of chemotherapy. The corresponding research has been published in Nature Communications and can be accessed at https://doi.org/10.1038/s41467-021-21714-2.

A facile method was developed to prepare carbon dots(CDs) by pyrolysis and etching of coffee residue. The as-prepared CDs show uniform spherical nanoparticles with an average size of 2.3 nm and exhibit excitation-dependent fluorescence emissions. Moreover, CDs also exhibit strong fluorescence quenching to nitro compounds and metal ions in both water and ethanol solutions, which could act as a platform for dual detection of PA(picric acid) and Fe³⁺ ions with low detection limits of 0.26 and 0.83 µmol/L, respectively. This work provides a novel method for preparation of environmental-friendly fluorescent CDs and shows their potential applications in photoluminescence sensors.

A sensitive and selective method employing chemiluminescence(CL) coupled with flow injection(FI) is reported for nalbuphine hydrochloride(NAL) assay in pharmaceutical formulations. The enhancement effect of NAL on the CL reaction between tris(2,2′-bipyridyl)ruthenium(II) chloride-diperiodatocuprate(III) {Ru[(bpy)₃]²⁺-Cu(III) complex} in acidic medium is used as analytical measurement. The optimal conditions of the CL reaction were sulfuric acid 1.0×10⁻³ mol/L, Ru[(bpy)s]²⁺ 7.5×10⁻⁵ mol/L, Cu(III)/Ag(III) complexes 4.0×10⁻⁴/5.0×10⁻⁴ mol/L, sample loop volume of 120 µL and flow rate of 2.5 mL/min. The sensitivities of the method in terms of detection(S/N=3) and quantification(S/N=10) limits are 5×10⁻⁴ and 0.001 ppm(1 ppm=1 mg/L), respectively. The linear response of the instrument in the form of CL intensity with respect to NAL concentration is over the range 0.001–15.0 ppm(R ²=0.9999) with relative standard deviation from 0.8% to 3.2% and injection throughput of 120 injection/h. The applications of the method include the quantitative analysis of NAL in pharmaceutical injection samples. Variations and the average results of the proposed method are not significantly different from the results of a reported method by applying F- and paired student t-test. The most likely CL reaction mechanism is written in accordance with spectrophotometric and CL studies.

An efficient and facile method was introduced for the synthesis of benzimidazoles in this paper. The optimum reaction conditions were determined. A series of benzimidazoles bearing phenolic hydroxyl(2a—2t) were synthesized in moderate to excellent yields starting from differently substituted hydroxyl benzaldehyde and 4-position substituted o-phenylenediamine via nu-cleophilic addition in the presence of catalyst Na₂S₂O₅ under microwave irradiation condition. Herein, effects of the catalyst, molar ratio of reactants, reaction temperature and solvent were investigated. The optimal reaction condition was determined. The effect of DMF and EtOH solvent on the reaction was compared. The synthesized compounds were characterized by FTIR, HRMS, ¹H NMR and ¹³C NMR spectroscopy. Further, the bacteriostatic activities of the synthesized compounds were evaluated with ciprofloxacin and itraconazole as a positive control, respectively. Compounds 2b, 2n, 2q and 2r exhibited some antibacterial activity. The lowest MIC of antibacterial activity of compound 2b was 32 µg/mL. Meanwhile, the luminescence property of compound 2b was studied. The antibacterial activity of compound 2b, along with their good fluorescence performance highlighted the potential of these compounds as lead structures and owned fluorescence trace for further study towards the development of novel drugs and functional mechanisms in living organisms.

A series of pyrrolo[2,1-c][1,4]benzodiazepine-3,11-dione derivatives was designed and synthesized, and their neuroprotective activity against SH-SY5Y cell injury induced by N-methyl-D-aspartic acid(NMDA) was evaluated. All the compounds showed significant neuroprotective effects, especially B16, which showed excellent performance and better activity than the positive control ifenprodil(B16: 56.2%±0.6%; ifenprodil: 41.0%±2.7%). Further investigation indicated that B16 could attenuate the Ca²⁺ influx induced by NMDA in SH-SY5Y cells and Western blotting also showed that B16 could attenuate the NR2B upregulation in SH-SY5Y cells induced by NMDA. The molecular docking results showed that compound B16 fitted in the binding pocket of NR2B-NMDAR well and could interact with binding sites of compounds 1 and 2 simultaneously. The ADME/Tox prediction results suggested that compound B16 had good blood-brain barrier(BBB) permeability and the zero alert of Pan Assay Interference Structures(PAINS) indicated that B16 could not elicit false-positive activities. These results strongly suggest that B16 is a promising and effective candidate neuroprotective compound, and that NR2B-NMDAR is a potential target of B16.

A series of novel anthranilic diamides analogues(9a–9t) containing trifluoroethoxyl pyrazole moiety was designed and synthesized and their insecticidal bioactivities against Mythimna separata(Walker, M. separata) and Plutellaxylostella (P. xylostella) were evaluated. The structures of the title compounds were confirmed by ¹H NMR, ¹³C NMR and HRMS. Preliminary insecticidal activities showed that some of the title compounds possessed good to excellent bioactivities towards M. separata and P. xylostella. Compounds 9c and 9t exhibited 100% mortality rate against M. separate at 0.2 mg/L. For the P. xylostella, the synthesized compounds(9c–9e, 9i and 9o) showed 70%, 80%, 75 %, 65% and 60% insecticidal activities at 1×10⁻⁶ mg/L, respectively, higher than that of chlorantraniliprole(0). Based on excellent insecticidal activities, the mode of the action was tested by the calcium-imaging technique, the results of which demonstrated that the novel compounds shared the same target with chlorantraniliprole. The binding pose of the most active compound 9t in RyRs of P. xylostella was predicted by molecular docking, which showed that compound 9t interacted with the residues Glu140(A) and His147(A) via hydrogen bond.

Through a facile structural modification on the natural bioactive ingredient 18β-glycyrrhetinic acid(GA), a series of novel GA hydrazide or amide derivatives was obtained, and their final molecular frameworks were characterized by NMR and HRMS analysis. Antibacterial bioassays revealed that some of the GA hydrazide or amide derivatives were able to suppress the growth of three tested plant pathogens. Particularly, compound 3c exhibited excellent in vitro activity against Xanthomonas oryzae pv. Oryzae (Xoo), Pseudomonas syringae pv. actinidiae(Psa), and Xanthomonas axonopodis pv. citri(Xac), providing the EC₅₀ values of 5.89, 16.1, and 3.64 µg/mL, respectively. The data were better than those of the positive controls thiodiazole copper(92.7, 77.8, and 89.9 µg/mL, respectively) and bismerthiazol(31.1, 125.6, and 77.4 µg/mL, respectively). In addition, in vivo experiments suggested that, compared with thiodiazole copper(41.93% and 39.73%, respectively), compound 3c exerted prominently curative and protective activities against rice bacterial leaf blight at 200 µg/mL with the control effects of 52.36% and 51.40%, respectively. Given these obtained results, GA hydrazide or amide derivatives could serve as the feasible leads for exploring highly bioactive substrates.

An ultrasonic-assisted synthesis of bis-isoxazole derivatives was developed. Eight 3-(6-chloropyridin-3-yl)-5-{[(3-arylisoxazol-5-yl)methoxy]methyl}isoxazoles were synthesized by 1,3-dipolar cycloaddition reaction between substituted isoxazolyl alkyne compounds and 6-chloro-N-hydroxynicotinimidoyl chloride. The structures of the synthesized compounds were confirmed by HRMS, FTIR, ¹H and ¹³C NMR spectroscopy. Wherein, the antifungal and antibacterial activities of target compounds were tested. The synthesized compounds 6a and 6h exhibited better antifungal activity in comparison with the standard drug itraconazole. The minimum inhibitory concentrations(MICs) of both compound 6a and compound 6h were both 4 µg/mL against Candida albicans ATCC 10231.

The host-guest interactions between cyclopentanocucurbit-[6]uril(CyP₆Q[6]) as host and six alkyl imidazolium hydrochloride as guests(g1, g2, g3, g4, g5, and g6) have been studied by various techniques, such as ¹H NMR spectroscopy, isothermal titration calorimetry, mass spectrometry, and single-crystal X-ray diffraction analysis. The experimental results showed that CyP₆Q[6] formed 1:1 inclusion complexes with each of guests g1–g6. The part of the guest entered the cavity of CyP₆Q[6] changes as the alkyl chain increases in length. It can be seen that the length of the alkyl chain plays a key role in determining the mode of host-guest interactions.

As a rising star among porous solid materials, covalent organic frameworks(COFs) with excellent properties including but not limit to facilely controllable structure, high porosity, and multi-chemical functionality represent significant potential for efficient ¹²⁷Xe/⁸⁵Kr capture and separation. In this study, through tuning the length of the organic ligands, two-dimensional(2D) COF materials with identical connection group but different pore properties, denoted as ATFG-COF and TpPa-COF with AA-stacking model and TpBD-COF with AB-stacking model were synthesized and tested for Kr and Xe adsorption for the first time. Adsorption measurements indicate that the narrower pore apertures and higher porosity are conducive for COF materials to capture Xe and Kr. Furthermore, the Henry’s constant, isosteric heat of adsorption(Q _st), and ideal adsorbed solution theory(IAST) selectivity of ATFG-COF, the pore size of which is closest to the kinetic diameter of the Xe atom(0.41 nm) among 2D COF materials, were carried out based on the single component sorption isotherms. The results illustrate that the high isosteric heat values of Xe/Kr adsorption on ATFG-COF are 25 and 16 kJ/mol at room temperature, respectively. Henry’s law predicts that the selectivity factor of Xe to Kr is 6.07, consistent with the adsorption selectivity(ca. 6) calculated based on the IAST.

In this paper, we describe the synthesis of the AC-PtNi/G catalysts with graphene as the carrier, via the alcohol reduction and the sulfuric acid treatment. The prepared catalysts were microscopically characterized by X-ray diffractometry(XRD), X-ray photoelectron spectroscopy(XPS), scanning electron microscopy(SEM), electron spectroscopy(EDAX), and transmission electron micros-copy(TEM). We tested the electrochemical performance of the prepared catalysts using an electrochemical workstation and in situ infrared spectroscopy(FTIR). The results showed that the acid-treated AC-PtNi/G catalysts had a more uniform dispersion and with the increased of treatment time, the particle size of the catalyst became smaller. And the electrocatalytic performance of the AC-PtNi/G-48h catalyst treated with sulfuric acid for 48 h was significantly better than that of the untreated PtNi/G catalyst. Its electrochemically active surface area was 76.63 m²/g, and the peak current density value for catalytic oxidation of ethanol was 1218.83 A/g, which was 10 times that of ordinary commercial Pt/C catalyst. The steady-state current density value of 1100 s was 358.77 A/g, and it has excellent anti-CO toxicity performance. It was determined that a sulfuric acid treatment controlled catalyst particle size and increased the electrocatalytic activity of the catalytic oxidation of ethanol.

In this paper, the early stages of nucleation and photoirradiation growth of CeO₂ thin films have been studied. Cyclic voltammetry, chronoamperometry and scanning electron microscopy were used to analyze the nucleation process of CeO₂ thin films deposited on the anode with photo irradiation. Experimental results show that the anodic deposition process with photo illumination is controlled by diffusion. Compared with the dark state, photo illumination mainly contributed to increase the current density of the three-dimensional nucleation process, because photo illumination is helpful to create active sites and accelerate the nucleation progress on the surface that a thin ceria film has been formed. Two-dimensional nucleation process mainly exists within the initial 2 s, and then only three-dimensional instantaneous nucleation process continues, which may be the main reason why the thickness of the CeO₂ film can continue to grow with photo illumination but not in the dark state. Increasing the deposition overpotential can promote two-dimensional nucleation and growth rate, whilst when the potential exceeds 0.65 V, three-dimensional current density decreases. The limiting factor at that time may be the diffusion rate of cerium ions in the solution towards the electrode substrate.

The Co₃O₄ decorated TiO₂ nanotube arrays(NTAs) coatings are fabricated by the combination of anodization and impregnating methods. It is found that the introduction of Co₃O₄ can reduce the diffraction intensity of (101) plane of the TiO₂ and accelerate the separation of photogenerated electron/hole pairs. In addition, the open circuit potential(OCP) and the corrosion potential of 304 stainless steel(304SS) with or without Co₃O₄ decorated TiO₂ NTAs were measured under visible light, which indicated the 304SS coupled with Co₃O₄ decorated TiO₂ NTAs had better anticorrosion performance than that of the 304SS or the 304SS coupled with pure TiO₂ NTAs. The enhancement of the cathodic protection performance of the Co₃O₄ decorated TiO₂ NTAs can be ascribed to the matched energy levels and strong interaction between Co₃O₄ and TiO₂ NTAs, and the improvement of light absorption.

Methyl pentanoate(MP) was identified as a potential candidate. To facilitate the application of MP with high efficiency in engines, a comprehensive understanding of combustion chemical kinetics of MP is necessary. In this work, the H-abstraction reactions from MP by H and CH₃ radicals, critical in controlling the initial fuel consumption, are theoretically investigated at the DLPNO-CCSD(T)/CBS(T-Q)//M06-2X/cc-pVTZ level of theory. The multistructural torsional(MS-T) anharmonicity is characterized using the dual-level MS-T method; the HF/3–21G and M06-2X/cc-pVTZ methods are chosen as the low- and high-level methods, respectively. The conventional transition state theory(TST) is employed to calculate the high-pressure limit rate constants at 298–2000 K with the Eckart tunneling correction. Our calculations indicate that the hydrogen atoms of the methylene functional group are easier to be abstracted by H and CH₃ radicals. The multistructural torsional anharmonicities of H-abstraction reactions MP+H/CH₃ are significant within the temperature range investigated. The tunneling effects are more pronounced at low temperatures, and contribute considerably to the rate constants below 500 K. The model from the work of Diévart et al. is updated with our calculations, and the simulations of the updated model are in excellent agreement with the reported ignition delay time of MP/O₂/Ar and MP/Air mixtures. The sensitivity analysis indicates that the H-abstraction reactions, MP+H-CH₃CH₂CHCH₂C(-O)OCH₃/CH₃CHCH₂CH₂C(-O)OCH₃+H₂, are critical in controlling the initial fuel consumption and ignition delay time of MP.

The best alternative to fight against corrosion is the use of an inhibitor, the purpose of this work is the formulation of a new biomass-based molecule against corrosion of carbon steel. Lignin was extracted using the Kraft process and phenylhydrazine molecules have been scratched. The influence of the lignin-phenyl-hydrazone(LP) on the corrosion of carbon steel in salt and the acidic medium was studied by the polarization resistance, the potentiodynamic polarization, and the electrochemical impedance spectroscopy. The results of these tests reveal that the behavior of the inhibitor is a mixed type. The adsorption mechanism of the inhibitor follows the Langmuir isothermal model. Gibbs energy shows that the process of inhibition of carbon steel is spontaneous. The SEM confirms that the inhibitor reduces the corrosion of the steel and stops the corrosion pitting phenomenon. The modified lignin shown as a good corrosion inhibitor in acid medium is highly saline with an efficiency > 96%.