Immobilization and Properties of Lipase from Candida rugosa on Electrospun Nanofibrous Membranes with Biomimetic Phospholipid Moities

Reported here is a protocol to fabricate a biocatalyst with high enzyme loading and activity retention, from the conjugation of electrospun nanofibrous membrane having biomimetic phospholipid moiety and lipase. To improve the catalytic efficiency and activity of the immobilized enzyme, poly（acrylonitrile-co-2-methacryloyloxyethyl phosphorylcholine）s（PANCMPCs） were, respectively, electrospun into nanofibrous membranes with a mean diameter of 90 nm, as a support for enzyme immobilization. Lipase from Candida rugosa was immobilized on these nanofibrous membranes by adsorption. Properties of immobilized lipase on PANCMPC nanofibrous membranes were compared with those of the lipase immobilized on the polyacrylonitrile（PAN） nanofibrous and sheet membranes, respectively. Effective enzyme loading on the nanofibrous membranes was achieved up to 22.0 mg/g, which was over 10 times that on the sheet membrane. The activity retention of immobilized lipase increased from 56.4% to 76.8% with an increase in phospholipid moiety from 0 to 9.6%（molar fraction） in the nanofibrous membrane. Kinetic parameter Km was also determined for free and immobilized lipase. The Km value of the immobilized lipase on the nanofibrous membrane was obviously lower than that on the sheet membrane. The optimum pH was 7.7 for free lipase, but shifted to 8.3-8.5 for immobilized lipases. The optimum temperature was determined to be 35 ℃ for the free enzyme, but 42-44℃ for the immobilized ones, respectively. In addition, the thermal stability, reusability, and storage stability of the immobilized lipase were obviously improved compared to the free one.

Electrospun Poly(acrylonitrile-co-acrylic acid) Nanofibrous Membranes for Catalase Immobilization:Effect of Porphyrin Filling on the Enzyme Activity

Porphyrin-filled nanofibrous membranes were facilely prepared by electrospinning of the mixtures of poly（acrylonitrile-co-acrylic acid）（PANCAA） and porphyrins. 5,10,15,20-Tetraphenylporphyrin（TPP） and its metal-loderivatives（ZnTPP and CuTPP） were studied as filling mediators for the immobilization of redox enzyme. Results indicate that the introduction of TPP, ZnTPP and CuTPP improves the retention activity of the immobilized catalase. Among these three porphyrins, the ZnTPP-filled PANCAA nanofibrous membrane exhibits an activity retention of 93%, which is an exciting improvement. This improvement is attributed to both the strong catalase-porphyrin affinity and the possible facilitated electron transfer induced by the porphyrin as evidenced by quartz crystal microbalance （QCM） and fluorescence spectroscopy studies.

Flexible regulation engineering of titanium nitride nanofibrous membranes for efficient electromagnetic microwave absorption in wide temperature spectrum

Simultaneous development of well impedance matching and strong loss capability has become a mainstream method for achieving outstanding electromagnetic microwave absorption(EMWA)performances over wide temperature range.However,it is difficult to pursue both due to the mutual restraint of relationship between impedance matching and loss capability about temperature.Here,we propose a flexible regulation engineering of titanium nitride(TiN)nanofibrous membranes(NMs,TNMs),which could be distributed uniformly in the polydimethylsiloxane(PDMS)matrix and contributed to the formation of abundant local conductive networks,generating the local conductive loss and enhancing the loss ability of EMWs.Moreover,when the TNMs are used as functional units and dispersed in the matrix,the corresponding composites exhibit an outstanding anti-reflection effect on microwaves.As hoped,under the precondition of good impedance matching,local conductive loss and polarization loss together improve the loss capacity at room temperature,and polarization loss can compensate the local conductive loss to acquire effective dielectric response at elevated temperature.Benefiting from the reasonably synergistic loss ability caused by flexible regulation engineering,the corresponding composites exhibit the perfect EMWA performances in a wide temperature range from 298 to 573 K.This work not only elaborates the ponderable insights of independent membrane in the composition-structure-function connection,but also provides a feasible tactic for resolving coexistence of well impedance matching and strong loss capability issues in wide temperature spectrum.

Biomimetic design of highly flexible metal oxide nanofibrous membranes with exceptional mechanical performance for superior phosphopeptide enrichment

Developing free-standing and mechanical robust membrane materials capable of superior enrichment of phosphopeptides for analyzing and identifying the specific phosphoproteome of cancer cells is significant in understanding the molecular mechanisms of cancer development and exploring new therapeutic approaches,but still a significant challenge in materials design.To this end,we firstly constructed highly flexible ZrTiO_(4) nanofibrous membranes(NFMs)with excellent mechanical stability through a cost-effective and scalable electrospinning and subsequent calcination technique.Then,to further increase the enrichment capacity of the phosphopeptide,the biomimetic TiO_(2)@ZrTiO_(4) NFMs with root hair or leaf like branch microstructure are developed by the hydrothermal post-synthetic modification of ZrTiO_(4) NFMs through growing unfurling TiO_(2) nanosheets onto the ZrTiO_(4) nanofibers.Importantly,remarkable flexibility and mechanical stability enable the resulting TiO_(2)@ZrTiO_(4) NFMs excellent practicability,while the biomimetic microstructure allows it outstanding enrichment ability of the phosphopeptide and identification ability of the specific phosphoproteins in the digest of cervical cancer cells.Specifically,6770 phosphopeptides can be enriched by TiO_(2)@ZrTiO_(4) NFMs(2205 corresponding phosphoproteins can be identified),and the value is much higher than that of ZrTiO_(4) NFMs(6399 phosphopeptides and 2132 identified phosphoproteins)and commercial high-performance TiO_(2) particles(4525 phosphopeptides and 1811 identified phosphoproteins).These results demonstrate the super ability of TiO_(2)@ZrTiO_(4) NFMs in phosphopeptide enrichment and great potential for exploring the pathogenesis of cancer.

Electroactive and antibacterial wound dressings based on Ti_(3)C_(2)T_(x)MXene/poly(ε-caprolactone)/gelatin coaxial electrospun nanofibrous membranes

Endogenous electric fields(EFs)are capable of regulating the behaviors of skin cells in wound healing.However,majority of current dressings are primarily engaged in the passive repair of defective tissue,as they lack the ability to actively respond to physiological electrical signals.In this work,a series of nanofibrous membranes(NFMs)were fabricated by coaxial electrospinning,combining the good mechanical properties of poly(ε-caprolactone)(PCL),the bioactivity of gelatin and the electroactivity of Ti_(3)C_(2)T_(x)MXene,as electroactive and antibacterial dressings for cutaneous wound healing.The obtained NFMs exhibited suitable mechanical properties and hydrophilicity,excellent electroactivity,antibacterial activity,and biocompatibility.Especially,Ti_(3)C_(2)T_(x)MXene/PCL/gelatin-6(MPG-6,6 wt.%of Ti_(3)C_(2)T_(x)MXene in sheath spinning liquids)showed the optimal conductivity and antibacterial activity.Excitingly,this scaffold significantly promoted the adhesion,proliferation,and migration of NIH 3T3 cells under the electrical stimulation(ES).The in vivo evaluation in a full-thickness wounds defect model demonstrated that the MPG-6 films significantly accelerated wound closure,increased granulation tissue formation,increased collagen deposition,and promoted wound vascularization.In summary,the versatile scaffold is expected to be an ideal candidate as wound dressings due to its ability to promote the transmission of physiological electrical signals and thus improved the therapeutic outcomes of wound regeneration.

Green Fabrication of Underwater Superoleophobic Biopolymeric Nanofibrous Membranes for Effective Oil-Water Separation

Currently,most of the materials for oil-water separation membranes are limited to fluorine-based polymers with low surface energy.However,it is not biodegradable and requires large amounts of organic and toxic solvents in the membrane manufacturing process.Therefore,interest in the development of a new eco-friendly oil-water separation membrane that does not cause secondary pollution and exhibits selective wettability characteristics in water or oil is increasing.The biopolymeric nanofibrous membranes inspired by fish skin can provide specific underwater oleophobicity,which is effective for excellent oil-water separation efficiency and prevention of secondary contamination.Fish gelatin,which is highly soluble in water and has a low gelation temperature,can be electrospun in an aqueous solution and has the same polar functional groups as the hydrophilic mucilage of fish skin.In addition,the micro/nanostructure of fish skin,which induces superoleophobicity in water,introduces a bead-on-string structure using the Rayleigh instability of electrospinning.The solubility of fish gelatin in water was removed using an eco-friendly crosslinking method using reducing sugars.Fish skin-mimicking materials successfully separated suspended oil and emulsified oil,with a maximum flux of 2086 Lm^(−2) h^(−1) and a separation efficiency of more than 99%.The proposed biopolymeric nanofibrous membranes use fish gelatin,which can be extracted from fish waste and has excellent biodegradability with excellent oil-water separation performance.In addition,polymer material processing,including membrane manufacturing and crosslinking,can be realized through eco-friendly processes.Therefore,fish skin-inspired biopolymeric membrane is expected to be a promising candidate for a sustainable and effective oil-water separation membrane in the future.

Diphylleia Grayi-Inspired Intelligent Temperature-Responsive Transparent Nanofiber Membranes

Nanofiber membranes(NFMs) have become attractive candidates for next-generation flexible transparent materials due to their exceptional flexibility and breathability. However, improving the transmittance of NFMs is a great challenge due to the enormous reflection and incredibly poor transmission generated by the nanofiber-air interface. In this research, we report a general strategy for the preparation of flexible temperature-responsive transparent(TRT) membranes,which achieves a rapid transformation of NFMs from opaque to highly transparent under a narrow temperature window. In this process, the phase change material eicosane is coated on the surface of the polyurethane nanofibers by electrospray technology. When the temperature rises to 37 ℃, eicosane rapidly completes the phase transition and establishes the light transmission path between the nanofibers, preventing light loss from reflection at the nanofiber-air interface. The resulting TRT membrane exhibits high transmittance(> 90%), and fast response(5 s). This study achieves the first TRT transition of NFMs, offering a general strategy for building highly transparent nanofiber materials, shaping the future of next-generation intelligent temperature monitoring, anti-counterfeiting measures, and other high-performance devices.

Highly flexible ceramic nanofibrous membranes for superior thermal insulation and fire retardancy

Ceramic membranes are attractive for thermal management applications due to its lightweight and ultralow thermal conductivity,while it is indispensable to address the long-standing obstacle of its poor mechanical stability and degradation under thermal shock.In this work,a series of the organic polymer template-modulated yttria doped zirconia(YDZ)nanofibrous membranes with lightweight,superior mechanical and thermal stability are developed through a cost-effective,scalable sol-gel electrospinning and subsequent calcination method.The YDZ membranes demonstrate excellent flexibility and foldability,which can be attributed to the tetragonal phase and small crystallite size of the YDZ fibers due to the presence of yttria.Besides,the fibrous size,grain size,mechanical and thermal stability of YDZ nanofibrous membranes could be tailored by varying the species and molecular weight of polymer template.The remarkable performances are obtained through the poly(vinyl pyrrolidone)(PVP)template YDZ nanofibrous membranes,featuring the superior tensile strength up to~4.82 MPa,excellent flexibility with bending rigidity~26 mN,robust thermal stability up to 1,200℃,ultra-low thermal conductivity of 0.008–0.023 W·m^(−1)·K^(−1)(25–1,000℃),and excellent flame retardancy with tolerance of flame up to 1,000℃.The remarkable properties can be attributed to the smaller fibrous size,and higher grain size resulting from PVP template.This robust material system is ideal for thermal superinsulation with a wide range of uses from energy saving building applications to spacecraft.

C60(OH)n-loaded nanofibrous membranes protect HaCaT cells from ROS-associated damage

Environmental stress factors could lead to the excess generation of reactive oxygen species（ROS） that induces various forms of skin damage related to oxidative stress. Polyhydroxylated fullerene derivative C（60）（OH）n, acting as an effective agent for prevention of skin aging, is widely used in the lotion and sunscreens in the field of cosmetics, but rarely used in the masks. In this study, we prepared C（60）（OH）n loaded nanofibrous membranes to protect human keratinocyte cells from ROS-associated damage and suppress the elevation of intracellular ROS and Ca（2＋） along with the apoptotic cell death. Two FDAapproved biodegradable polymers, PLGA and PCL, have been used for making the electrospun nanofibers,with C（60）（OH）n added to the polymers as an antioxidant. The nanofibrous membranes with good biocompatibility might be potentially applied in clinical practice to reduce skin aging.

SOUND ABSORPTION BEHAVIOR OF ELECTROSPUN POLYACRYLONITRILE NANOFIBROUS MEMBRANES

The acoustical damping property of electrospun polyacrylonitrile （PAN） nanofibrous membranes with different thicknesses and porosities was investigated. The sound absorption coefficients were measured using the impedance tube instrument based on ISO10534-2：1998（E）. Results indicate that the first resonance absorption frequency of nanofibrous membranes shifts to the lower frequency with the increase of the back cavity or the thickness of membranes. Moreover, the sound absorption performance of the perforated pane/ can be greatly improved by combination with a thin layer of PAN nanofibrous membrane. Traditional acoustical damping materials （foam, fiber） coated with nanofibrous membranes have better acoustical performance in the low and medium frequency range than that of acoustical materials alone. All of the results demonstrate the PAN nanofibrous membrane is a suitable candidate for noise reduction.

Multi-functional polyethersulfone nanofibrous membranes with ultra-high adsorption capacity and ultra-fast removal rates for dyes and bacteria

The adsorption technology has been widely applied in water remediation for contamination removal of dyes and bacteria,by virtue of the advantages of adsorption technology including high efficiency,energy conservation and ease of operation.Simultaneous removal of dyes and bacteria has been realized by some reported materials,but to achieve satisfactory adsorption amounts and rates remain an unmet goal for decades.Herein,a poly(methacrylatoethyl trimethyl ammonium chloride-co-methyl methacrylate)copolymer was synthesized,and then blended with polyethersulfone for the fabrication of nanofibrous membranes via electrospinning for the use of fast and massive removal of dyes and bacteria.Owing to the introduction of abundant quaternary ammonium groups,the maximum adsorption amount for methyl orange was up to 909.8 mg g^(-1).In addition,the modified nanofibrous membranes showed good recyclability,broad applications in severe environments,selective adsorption ability,and excellent dynamic removal performance.Especially,thanks to the abundant functional groups,the membranes showed fast adsorption ability for bacteria through electrostatic interaction.It should be noted that the clearance ratio for Staphylococcus aureus or Escherichia coli by 6 min of static adsorption could reach 93%or 90%for each.Additionally,dynamic removal ratio via filtration with the nanofibrous membranes could reach 99.7%for Staphylococcus aureus or 98.7%for Escherichia coli in 90 s.Therefore,the proposed approach towards the quaternary ammonium modified polyethersulfone nanofibrous membranes creates a new route for ultra-high adsorption capacity and ultra-fast removal rates for dyes and bacteria in water remediation.

High Performance Electrospun Polynaphthalimide Nanofibrous Membranes with Excellent Resistance to Chemically Harsh Conditions

Polynaphthalimide(PNI)with six-membered imide ring(_(6-)PI)has better chemical resistance than five-membered imide ring(_(5-)PI),but is difficult to be processed into nano fibers due to the poor processability.In this work,we proposed a template strategy to fabricate nanofiber _(6-)PI membranes and their composite membranes.Neat _(6-)PI and _(6-)PI composite fibrous membranes were prepared using high-molecular-weight polymers _(5-)PAA and PVP as templates by electrospinning.FTIR,DMA,TGA and tensile tests were used to characterize their chemical structures,thermal stability and mechanical properties.Further eye-observation,micro-morphology investigation and tensile tests were applied to evaluate the chemical resistance of nanofibrous membranes in strong acid,strong alkaline,and concentrated salt.The results demonstrated that 6-PI nano fibrous membra nes possessed the best thermal stability,best acid,alkaline,and salt resista nee with the highest mecha nical rete ntion.This study will provide basic information for high-performance electrospun 6-PI nanofiber membranes and provide opportunities for applications of Pls in different chemically harsh environments.

Electrospinning Preparation ofβ-Cyclodextrin/Glutaraldehyde Crosslinked PVP Nanofibrous Membranes to Adsorb Dye in Aqueous Solution

The insoluble β-cyclodextrin/glutaraldehyde crosslinked polyvinylpyrrolidone nanofibrous membranes were prepared by electrospinning technique. The membranes were extensively characterized by various techniques including attenuated total reflectance Fourier transform infrared spectroscopy（ATR-FTIR）, X-ray diffraction（XRD）, scanning electron microscopy（SEM） and UV-visible absorption to correlate membrane characteristics with their performance. The adsorption ability of the nanofibrous membranes was tested by performing extraction of Methyl orange（MO） dye in water. It was observed that β-cyclodextrin incorporated in polyvinylpyrrolidone provided the characteristics of high adsorption capacity of polyvinylpyrrolidone. Results of sorption experiments show that the nanofibrous membranes exhibited an adsorption rate of more than 95% for MO and the MO absorbent was 39.82 mg to per gram of fl-cyclodextrin glutaraldehyde（β-CDXFM） crosslinked PVP under the optimized experimental conditions.

Coordination of thin-film nanofibrous composite dialysis membrane and reduced graphene oxide aerogel adsorbents for elimination of indoxyl sulfate

The protein-bound uremic toxins,represented by indoxyl sulfate(IS),have been associated with the progression of chronic kidney disease and the development of cardiovascular disease in the presence of impaired renal function.Herein,we proposed a novel strategy of thin-film nanofibrous composite(TNFC)dialysis membrane combined with reduced graphene oxide(rGO)aerogel adsorbents for clinical removal of IS as well as high retention of proteins.The TFNC membrane was prepared by electrospinning in conjunction with coating-reaction method and proved to have good selectivity and permeability.To further improve the removal rate of toxins,we used a medium hydrothermal method following by freeze-drying treatment to obtain the r GO aerogel adsorbents.It exhibited excellent adsorption for IS with a maximum adsorption capacity of 69.40 mg·g^(-1)throughπ-πinteraction and hydrogen bonding interaction based on Langmuir isotherm models.Time-dependent absorption experiments showed that it reached adsorption equilibrium within 4 h,which was matched with the hemodialysis time.The coordination was significantly exhibited by introducing r GO aerogel blocks into the dialysate for absorbing the diffused free IS during hemodialysis.Taking the advantages of the TFNC dialysis membrane and the rGO aerogel,the volume of dialysate for hemodialysis was only one-tenth of that without adsorbent blocks but with very comparable dialysis performance(the clearance of IS at 51.8%and the retention of HSA over 98%),which could lighten conventional hemodialysis effectively and be benefit to realize the miniaturization of the hemodialysis equipment.Therefore,the coordination of the TFNC dialysis membrane and rGO aerogel adsorbents would open a new path for the development of portable artificial kidney.

Collagen/Chitosan Electrospun Nanofibrous Membrane for Wound Dressing

Collagen(Col)/chitosan(CS)nanofibrous membrane has great potential to be used as wound dressing.However,current Col/CS nanofibrous membrane produced from electrospinning can not offer sufficient mechanical strength for practical applications.Herein,a novel mixed solvent was used to prepare next-generation high-strength Col/CS nanofibrous membrane.Meanwhile,the optimal Col to CS weight ratio was investigated as well.The asproduced membrane was examined by scanning electron microscopy(SEM),attenuated total reflectance Fourier transform infrared spectroscopy(ATR-FTIR),differential scanning calorimetry(DSC),and XF-1A tester to study its morphological,chemical,thermal and mechanical properties.The preliminary results demonstrated that the mechanical properties of Col/CS nanofibrous membranes were enhanced substantially with the increase of CS weight ratios from 0 to 90%and the optimal Col to CS weight ratio was determined to be 1∶1.A promising way was presented to fabricate Col/CS electrospun nanofibrous membrane with sufficient mechanical strength for practical wound dressing applications.

Simulation of Structural Characteristics and Depth Filtration Elements in Interconnected Nanofibrous Membrane Based on Adaptive Image Analysis

Due to their unique structural features, electrospun membranes have gained considerable attention for use in applications where quality of depth filtration is a dominant performance factor. To elucidate the depth filtration phenomena it is important to quantify the intrinsic structural properties independent from the dynamics of transport media. Several methods have been proposed for structural characterization of such membranes. However, these methods do not meet the requirement for the quantification of intrinsic structural properties in depth filtration. This may be due to the complex influence of transport media dynamics and structural elements in the depth filtration process. In addition, the different morphological architectures of electrospun membranes present obstacles to precise quantification. This paper seeks to quantify the structural characteristics of electrospun membranes by introducing a robust image analysis technique and exploiting it to evaluate the permeation-filtration mechanism. To this end, a nanostructured fibrous network was simulated as an ideal membrane using adaptive local criteria in the image analysis. The reliability of the proposed approach was validated with measurements and comparison of structural characteristics in different morphological conditions. The results were found to be well compatible with empirical observations of perfect membrane structures. This approach, based on optimization of electrospinning parameters, may pave the way for producing optimal membrane structures for boosting the performance of electrospun membranes in end-use applications.

Enhanced coalescence separation of oil-in-water emulsions using electrospun PVDF nanofibers

A novel and high-efficiency coalescence membrane enhanced by nano-sized polyvinylidene fluoride(PVDF)nanofibers based on polyester(PET)substrate was fabricated using electrospinning method.The properties of the electrospun nanofibers such as roughness and surface morphology greatly affected the oil droplet interception efficiency and surface wettability of the membrane.A series of coalescence units were prepared with different layers of nanofibrous membrane and the separation efficiencies at different initial concentrations,flow rates,and oil types were tested.It is very interesting that the obtained nanofibrous membrane exhibited superoleophilicity in air but poor oleophilicity under water,which was beneficial to the coalescence process.The coalescence unit with four membrane layers had excellent performances under different initial concentrations and flow rates.The separation efficiency of the 4-layers unit remained above 98.2%when the initial concentration reached up to 2000 mg·L-1.Furthermore,the unit also exhibited good performance with the increasing oil density and viscosity,which is promising for large-scale oil wastewater treatment.

Electrospun Nanofibrous Adsorption Membranes for Wastewater Treatment:Mechanical Strength Enhancement

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.

Hierarchical CuO-ZnO/SiO_(2) Fibrous Membranes for Efficient Removal of Congo Red and 4‑Nitrophenol from Water

Hierarchical CuO-ZnO/SiO_(2)(CZS)nanofibrous membranes are designed and fabricated to remove Congo red and 4-nitro-phenol two common small molecular pollutants in water.The electrospun SiO_(2) fibrous membrane is serves as the substrate for hydrothermal depositing CuO-ZnO nanosheets.The CZS nanofibrous membrane shows good adsorption characteristics for Congo red due to the hierarchical morphology and the adsorption kinetics where isotherm follows the pseudo-second-order model and Langmuir model,respectively.The maximum adsorption capacity for Congo red is 141.8 mg/g.Moreover,the membrane exhibits excellent catalytic reduction activity for 4-nitrophenol under mild conditions and over 96%of the pollut-ants are degraded within 90 s.The CZS nanofibrous membrane has promising prospects in applications in water treatment and environmental protection because of the good flexibility,easy fabrication,excellent adsorption,and catalytic activity.

Fabrication of metal-organic framework-based nanofibrous separator via one-pot electrospinning strategy

Metal-organic framework(MOF)/polymer composites have attracted extensive attention in the recent years.However,it still remains challenging to efficiently and effectively fabricate these composite materials.In this study,we propose a facile one-pot electrospinning strategy for preparation of HKUST-1/polyacrylonitrile(PAN)nanofibrous membranes from a homogeneous stock solution containing HKUST-1 precursors and PAN.MOF crystallization and polymer solidification occur simultaneously during the electrospinning process,thus avoiding the issues of aggregation and troublesome multistep fabrication of the conventional approach.The obtained HKUST-1/PAN electrospun membranes show uniform MOF distribution throughout the nanofibers and yield good mechanical properties.The membranes are used as separators in Li-metal full batteries under harsh testing conditions,using an ultrathin Li-metal anode,a high mass loading cathode,and the HKUST-1/PAN nanofibrous separator.The results demonstrate significantly improved cycling performance(capacity retention of 83.1%after 200 cycles)under a low negative to positive capacity ratio(N/P ratio of 1.86).The improvement can be attributed to an enhanced wettability of the separator towards electrolyte stemmed from the nanofibrous structure,and a uniform lithium ion flux stabilized by the open metal sites of uniformly distributed HKUST-1 particles in the membrane during cycling.