Composite Fiber Membranes Research Articles

Construction of a high-performance hollow fiber composite NF membrane via the simultaneous modification of substrate and selective layer

Hollow fiber composite (HFC) nanofiltration (NF) membrane demonstrates significant commercial potential profiting from its self-supporting characteristic, high packing density and strong fouling resistance. In this work, a high-performance HFC NF membrane was successfully developed through simultaneous modification of the substrate via alkaline hydrolysis and incorporation of iopamidol (IPD) into the selective layer. Alkaline hydrolysis enhanced the hydrophilicity of the polyacrylonitrile (PAN) substrate by converting –CN groups into –COOH, thereby sharply improving the success rate of HFC NF membrane fabrication. The addition of IPD into piperazine (PIP) solution effectively increased the water permeability of the HFC NF membrane without compromising its salt rejection. Specifically, the optimized membrane sample denoted as NF-0.15P + 0.5I with 0.5 w/v% IPD added demonstrated a 44 % increase in PWP from 21.8 L·m−2·h−1·bar−1 to 31.5 L·m−2·h−1·bar−1, while maintaining a Na2SO4 rejection over 96.8 %. This improvement can be attributed to the decreased selective layer thickness and reduced MWCO. Furthermore, the membrane exhibited exceptional dye/salt separation performance. This work represents a novel approach leading to the development of a HFC NF membrane suitable for dye/salt separation.

All-Perfluorosulfonated-Ionomer Composite Membranes Containing Blow-Spun Fibers: Effect of a Thin Fiber Framework on Proton Conductivity and Mechanical Properties.

In this study, thin fiber composite polymer electrolyte membranes (PEMs) were prepared using short side-chain perfluorosulfonic acid (PFSA) ionomers, Aquivion, to create composite PEMs with improved proton conductivity and improved mechanical properties. PFSA thin fiber webs prepared by blow spinning and successive hot pressing were used as the porous substrate. Herein, PFSA ionomers were used for both the substrate and the matrix of the composite PEMs, and their structures, properties, and fuel cell performance were characterized. By adding the PFSA thin fiber webs to the matrix, the proton conductivity was enhanced and the mechanical properties were slightly improved. The prepared PFSA thin fiber composite PEM showed better FC performance than that of the pristine PFSA one for the high-temperature low-humidity condition in addition to the low-temperature high-humidity one. To the best of our knowledge, this is the first report on the all PFSA composite membranes containing a PFSA thin fiber framework.

Hyperbranched polymer hollow-fiber-composite membranes for pervaporation separation of aromatic/aliphatic hydrocarbon mixtures

The separation of aromatic/aliphatic hydrocarbon mixtures is crucial in the petrochemical industry. Pervaporation is regarded as a promising approach for the separation of aromatic compounds from alkanes. Developing membrane materials with efficient separation performance is still the main task since the membrane should provide chemical stability, high permeation flux and selectivity. In this study, the hyperbranched polymer (HBP) was deposited on the outer surface of a polyvinylidene fluoride (PVDF) hollow fiber ultrafiltration membrane by a facile dip-coating method. The dip-coating rate, HBP concentration, and thermal cross-linking temperature were regulated to optimize the membrane structure. The obtained HBP/PVDF hollow fiber composite membrane had a good separation performance for aromatic/aliphatic hydrocarbon mixtures. For the 50%/50% (mass) toluene/n-heptane mixture, the permeation flux of optimized composite membranes could reach 1766 g·m–2·h–1 with the separation factor of 4.1 at 60 °C. Therefore, the HBP/PVDF hollow fiber composite membrane have great application prospects in the pervaporation separation of aromatic/aliphatic hydrocarbon mixtures.

“Rooting” engineering strategy for construction of highly stable, scalable, size-customized oxidized graphene/PA6 ultrafine fiber composite nanofiltration membranes for water purification

Nanofiltration membranes based on graphene oxide exhibit substantial potential for practical applications in water treatment, poised to lead the next generation of separation technology. It is noteworthy that the prominent hydration interaction among graphene–graphene oxide nanosheets stands as the primary factor influencing its stability. Simultaneously, the absence of suitable graphene substrates presents challenges to its large-scale production. In this study, our initial endeavor involved constructing a graphene-based selective layer on a PA6 substrate using a quasi-“rooting” strategy. The graphene selective layer was anchored onto the surface of PA6 fibers (with a diameter size of up to 190.0 mm and a selective layer thickness of approximately 5.0 µm). Experimental results reveal that the permeability of the hybrid graphene oxide/PA6 fiber composite nanofiltration membrane consistently maintained within the range of 7.7 to 14.9 L m⁻² h⁻¹ bar⁻1, with a remarkable dye molecule removal rate of 99.06 %. Even under challenging operating conditions (such as strong acid, strong alkali, polar solvent, oxidation, and the coexistence of salt ions), its separation performance remained stable. The permeability of composite membranes was retained between 10.6 and 12.7 L m⁻² h⁻¹ bar⁻1, and the rejection rate of CR dye reached 95.0 % under harsh conditions. Furthermore, the stability and anti-fouling performance of the composite membrane were significantly enhanced. Deposits on the membrane surface could be effectively removed through physical wiping and repeated water rinsing, maintaining membrane integrity even after vigorous ultrasonic cleaning (120 min, 950 W). Additionally, after undergoing 20 cycles of rinsing with deionized water and a 30-day soak in an aqueous solution, the PA6 substrate and graphene selective layer exhibited robust adhesion. No shedding was observed, and the dye rejection rate of the composite membrane consistently exceeded 95 %. This perfectly illustrates the exceptional structural stability and separation durability of the prepared separation membrane. Our work contributes fundamental design principles and theoretical insights for practical applications.

Hydrophobic hollow fiber composite membranes based on hexadecyl-modified SiO2 nanoparticles for toluene separation

In this work, we present a cost-effective and affordable inorganic silicon material known as nano-SiO2. The purpose of this work is to enhance the performance of toluene separation by utilizing modified-SiO2/polydimethylsiloxane (PDMS) nanocomposite membranes. To achieve this, we successfully grafted hexadecyltrimethoxysilane (HDTMS) onto the surface of nano-SiO2 and systematically investigated the impact of SiO2 concentration on the separation efficiency. Various techniques such as scanning electron microscopy (SEM) and water contact angle (WCA) and Fourier transform infrared (FT-IR) spectrum analyses were employed to analyze the surface morphology, hydrophobic properties, and functional groups of modified polyvinylidene fluoride (PVDF) hollow fiber membranes. In brief, 400 ppm of each volatile organic compound (toluene) was injected into the module as a feed for 10 min at 25 °C under a pressure of 1 bar at room temperature. Gases in the retentate were analyzed by GC/FID in purge and trap analyzers at 250 °C. The VOCs were sampled using an Automated Purge & Trap Sampler. After comparing the chromatographic data to the reference compounds, the adsorption capacity was calculated to identify residual VOCs collected after separation by the nanocomposite membrane as present in the feed. Among the tested modules, 0.2HPM (hollow fiber membranes coated with 20 wt% PDMS and 0.2 wt% hexadecyl-modified SiO2) exhibited the highest toluene removal efficiency of 95.7 % under conditions of 400 mL/min flow rate and 1 bar pressure. The findings of this study provide valuable insight into the hydrophobic modification of nano-SiO2 and its potential application as a membrane-based separation technique.

Morphology control of polylactic acid/ZIF-8 composite fiber membranes and adsorption performances for dye and antibiotic

Morphology control of polylactic acid/ZIF-8 composite fiber membranes and adsorption performances for dye and antibiotic

Photothermal-driven pH-responsive fiber composite membrane for oil-wastewater purification

Oil spills and the discharge of organic wastewater have posed a severe danger to environmental security. To address this issue, various functional oil/water separation materials for wastewater purification have been developed. In this work, MXene/PPy was loaded on PP fiber by simple in-situ polymerization and vacuum-assisted filtration technology. Polypropylene was modified by dopamine (PDA) through in-situ polymerization, to improve the loading fastness of MXene/PPy on the surface of PP. To increase the durability of the fiber membrane, the pH-responsive polymer (PDM) was simply immersed on the outer layer. The successfully prepared PP-MXene/PPy-PDM has excellent pH response and photothermal conversion performance. When pH= 2, the water contact angle (WCA) was 52°. When pH= 12, WCA was 125°. The surface of PP-MXene/PPy-PDM was heated to 104.6 ℃ in ten minutes under the irradiation of 2 kW·m−2. PP-MXene/PPy-PDM could continuously separate oil/water mixture for 12 h, and the highest separation flux was 3.87 kg·m−2·h−1. Moreover, PP-MXene/PPy-PDM has excellent stability, corrosion resistance and recyclability. This study provided a new strategy for preparing intelligent responsive fiber composite membrane for oil-water separation, which has a wide range of practical applications in the treatment of oily wastewater.

Phase change composite fiber membranes based on polyurethane/polyethylene glycol/silica with super-wetting and photothermal properties

Phase change materials (PCMs) temperature regulation by absorbing or releasing heat. Meanwhile, silicon dioxide nanoparticles (SiO2 NPs) can effectively increase the reflectance of visible and near-infrared light, lowering the surface temperature of fibers. In this study, electrospinning technology was employed to fabricate polyurethane/polyethylene glycol (PU/PEG) fiber membranes, which were made with PEG serving as thermal energy storage material and PU acting as a mechanically strong supporting material. Then, a layer of SiO2 NPs was electrosprayed onto the surface of phase change fibers, finally creating a composite fiber membrane with superwettability and a photothermal regulating function. The results showed that, although the static WCA of PU/PEG/SiO2 fiber membrane reached around 115.4°, liquid water droplets (100 μL) slowly penetrated into the fiber membrane and the penetrating velocity was faster than that of a hydrophilic PU/PEG membrane. The melting enthalpy (ΔHm) of the fiber membrane could be kept at 86.30 J/g when the loading amount of PEG was 1.25 times that of the PU. The phase change fiber membrane's variations in the ΔHm and crystallization enthalpy (ΔHc) after 100 heating-cooling cycles were less than 5 %, indicating its great thermal stability. Through the introduction of hydrophilic SiO2 NPs, the average reflectance of PU/PEG/SiO2 fiber membranes in visible and near-infrared light at 500–1250 nm was increased to 85.17 %. After 40 min of xenon lamp irradiation, the surface temperature of PU/PEG/SiO2 fiber membranes was 4.19 °C lower than that of fibers without SiO2 NPs, demonstrating its effective cooling ability. This work proposes an effective strategy for preparing intelligent textiles with features, such as quick drying, infrared stealth and refrigeration capabilities.

Electrospinning to fabricate composite membranes with improved superhydrophobic properties for efficient oil-water separation

The pursuit of developing quickly prepared, multifunctional, selective, and highly efficient fiber membranes has gained significant attention, particularly in oil-water separation treatment. The present study successfully fabricated composite membranes consisting of Polystyrene/polyacrylonitrile-polyvinylidene fluoride/polydimethylsiloxane- Iron tetraoxide nanoparticles (PS/PAN-PVDF/PDMS@Fe3O4) through the electrospinning technique. The prepared composite membranes' surface morphology, wettability, and separation efficiency were tested and characterized. The results demonstrate the exceptional superhydrophobic and lipophilic properties of the composite membrane. The Fe3O4 nanoparticle-doped fiber membrane exhibits consistent superhydrophobicity (contact angle exceeding 150°) in diverse acid and alkali environments while demonstrating controlled motion in a magnetic field. The fabricated composite fiber membrane exhibited effective adsorption of various oils, including peanut oil, silicone oil, and Span 80, achieving adsorption capacities ranging from 60 to 100 g/g. The membrane exhibited separation flux and efficiency values of 8067 L.m−2h−1 and 97.6% under gravity-driven conditions, respectively. Even after 40 cycles of separating acidic-alkaline oil-water mixtures, the separation flux remained at 5000 L.m−2.h−1. Hence, the prepared composite fiber membrane can be applied in oil-water separation.

Investigation on the mechanical properties of composite fiber membranes with different concentration of EVOH/Ag/AC

There are several requirements of properties for filter material: adsorption, antibacterial property, air permeability, mechanical properties, etc. Electrospinning technology is a recognized method with great potential to fabricate nanofiber membrane. In particular, the mechanical properties need to be well understood for applications where the membrane is subjected external loading, e.g. tension forces which could be monotonic or cyclic. In this study, the mechanical properties of ethylene vinyl alcohol (EVOH) nanofiber membranes loaded with silver nanoparticles (AgNPs) and activated carbon (AC) were investigated in detail. Static load tensile tests were carried out for nine groups of membranes with different mass fraction of EVOH (7.5%, 10%, 12.5%) and concentration ratios of Ag/AC (2:5, 1:1, 5:2). The results showed that the tensile strength and Young’s modulus of this membrane would increase with the increase of EVOH mass fraction. When the mass fraction of EVOH is 7.5% and the concentration ratio of Ag/AC is 1:1, the fracture strength of nanofiber membrane was the highest, which was 0.1545 MPa.

Preparation of graphene oxide/carboxymethyl chitosan/polyvinyl alcohol composite nanofiber membranes by electrospinning for heavy metal adsorption

AbstractIn this paper, a graphene‐oxide/carboxymethyl‐chitosan/polyvinyl‐alcohol (GO/CMC/PVA) composite nanofiber membrane was prepared by electrospinning and cross‐linking with glutaraldehyde (GA) to improve the water resistance. The composite nanofiber membrane can be used in the field of heavy metal adsorption. The membrane was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X‐ray diffraction. The effects of GO concentration, adsorption time, and initial concentration of heavy‐metal ion (Ni2+, Cu2+, Ag+, and Pb2+) solution on the adsorption performance of the fiber membranes were investigated. The results showed that the addition of GO can reduce the diameter of nanofibers. GO, CMC, and PVA exhibited good compatibility, and the intermolecular hydrogen bonding improved. The addition of GO also improved the crystalline properties of the composite fiber membrane. In the optimal cross‐linking condition, GA was saturated by steam cross‐linking for 6 h. The introduction of GO improved the adsorption capacity of the membrane for heavy metals in water. The utmost adsorption capacities for Ni2+, Cu2+, Ag+, and Pb2+ were 262.1, 237.9, 319.3, and 413.6 mg/g when using the cross‐linked composite fiber membranes, respectively. The results of adsorption kinetics and thermodynamics showed that the adsorption process accorded with the pseudo‐second‐order kinetic model and Langmuir–Freundlich isotherm model.

Efficient purification of high-salt rural groundwater in the areas along the Yellow River in Henan Province, China, by hollow fiber membrane distillation process

The vast rural drinking water sources along the Yellow River basin in Henan Province mainly come from the local high-salinity groundwater, which cannot be directly drunk. Zeolitic imidazolate framework-71/polyvinylidene fluoride hollow fiber composite membrane was applied to treat rural groundwater through membrane distillation technology. The variations of water quality parameters from 12 different rural regions after membrane distillation treatment were well analyzed and compared. Membrane separation performance for water samples from different regions during the membrane distillation process was investigated, including water flux and salt rejection. During a continuous 24-h membrane distillation process for the treatment of these water samples, hollow fiber membrane exhibits high solute retention rates (>99%) for salt ions, suspended solids and total dissolved solids, which are within the limits of national standards (GB 5749-2006), meanwhile membrane permeation water flux can remain stable. After the acid-cleaning for 180 min, all hollow fiber membranes can recover water flux well with a flux recovery rate above 98%. Even if the concentration ratio continued to increase, the water production rate of membrane distillation was basically maintained between 50% and 60%, which was obviously higher than the 30% of the reverse osmosis process. The economic analysis confirmed that the water production cost varied between US$0.45 and US$0.29/m3. With the extension of membrane service life, the specific membrane cost decreased rapidly in the first 6 years and then leveled off. The proposed vacuum membrane distillation process proved to be a promising water purification method for treating rural high-salinity groundwater.

PET Composite Fiber Membranes Modified with Modified Nanoscale ZnO Exhibit Synergistic Antibacterial Effects

PET Composite Fiber Membranes Modified with Modified Nanoscale ZnO Exhibit Synergistic Antibacterial Effects

Preparation of long-lasting releasing methyl eugenol fiber membrane and its trapping analysis on Bactrocera dorsalis

Methyl eugenol (ME) is a highly potent sexual attractant for Bactrocera dorsalis, which plays a crucial role in agricultural pest management. In this study, a composite fiber membrane was prepared by polystyrene (PS), polyethylene glycol diacrylate (PEGDA), and ME through electrostatic spinning respectively. The effective release period of ME was prolonged by triggering PEGDA with UV light. The mass ratio of PS to PEGDA affects the morphology of the fibers as well as the loading capacity (LC) and encapsulation efficiency (EE) for ME. Under optimal test conditions, the diameter of the fibers was 1.70 μm, and the ME loading capacity and encapsulation efficiency were (7.80 ± 0.07%) and (85.84 ± 7.94%). The combination of PS and PEGDA was confirmed by FTIR analysis, while its excellent thermal stability was verified through TGA testing. In the PS/PEGDA-ME-UV membrane, the cumulative release rate of ME reached 81.97% by week 8, which conformed to a first-order model. In the trapping experiments, a 53% rate of Bactrocera dorsalis capture was maintained even by week 8, demonstrating its potential for application in agricultural biocontrol.

Construction of Electrostatic Spinning Membranes Based on Conjugated Hemicyanine Derivatives for Photodynamic Antibacterial Application.

The preparation of efficient antibacterial membrane materials is one of the important strategies to fight against bacterial infection and alleviate drug resistance. Herein, hemicyanine derivatives with different chain lengths (C3, C6, and C10) that exhibit excellent photodynamic antibacterial activity were doped into spinnable polyvinyl alcohol solution (PVA, 8%) to obtain composite fiber membrane Cn/PVA (C3/PVA, C6/PVA, and C10/PVA) by a simple "one-pot" method using electrospinning technology. The antibacterial nanofiber membrane has a dense fiber structure which has a good interception effect, high thermal stability, and great biocompatibility. Importantly, Cn/PVA nanofibers could efficiently sensitize oxygen to generate reactive oxygen species (ROS), leading to high photokilling efficacy against drug-resistant bacteria. The variation of structure for hemicyanines causes the difference of Cn/PVA nanofibers in the effects of antibacterial performance, and it is found that C3/PVA and C10/PVA with three and ten carbons in the alkyl chain could kill more than 97% of ampicillin-resistant E. coli, which is much better than that of C6/PVA. Moreover, C3/PVA and C10/PVA exhibited killing efficiencies of 98.6 and 90.6% against MRSA, respectively. The construction of Cn/PVA composite fibers provides research ideas for the development of structure-dependent antimicrobial surface materials and is expected to be applied as superficial medical antibacterial protection materials.

Synthesis of organic–inorganic hybrid flame retardant and its use in polyurethane composite fiber membrane

AbstractIn this article, we presented an inventive organic–inorganic hybrid flame retardant, MPKG, by the strategic reaction of phytic acid (PA) with melamine (MA), γ‐aminopropyl triethoxysilane (KH550) and graphene oxide (GO). Subsequently, an MPKG/PU fiber membrane was fabricated through electrospinning, wherein MPKG was seamlessly incorporated into the PU spinning solution. The morphology and chemical structures of the flame retardants were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and x‐ray photoelectron spectroscopy (XPS). The flame retardancy and resilience to soaping of the fiber membranes were assessed via the limiting oxygen index (LOI), thermogravimetric analysis (TGA), and microscale combustion calorimetry (MCC). Impressively, the results demonstrate a significant 38.8% reduction in total heat release (THR) for the MPKG/PU fiber membrane in comparison to pure PU fiber membrane. Moreover, the incorporation of MPKG leads to an increase in LOI from 18.8% to 21.5% for the PU fiber membrane, accompanied by a notable enhancement in char yield at 800°C from 13.5% to 28.5%. These results underscore the augmentative impact of MPKG on the flame retardancy of PU fiber membrane. Remarkably, the MPKG/PU fiber membrane exhibits robust soaping resistance, with the LOI maintaining a level above 20% post‐soaping.

PPS composite membrane preparation based on aramid and glass fiber woven fabric support

Polyphenylene sulfide@aramid fiber (PPS@AF) composite membrane was synthesized using the dip drawing method. This involved coating a PPS separating membrane over both sides of AF support via the thermally induced phase separation (TIPS) method. In order to overcome the drawbacks of a dense skin and limited flux, we explored the influence of PPS concentration in the casting solution on membrane morphology and PPS composite membrane performance. Compared to the 6.7 N of PPS membrane, the prepared composite membrane displayed a tensile strength up to 445 N. The pure water flux of PPS composite membrane can reach 888.15 L⋅m−2⋅h−1 ⋅bar−1, which is 20.7 times greater than that of PPS membrane. We also successfully developed a PPS composite membrane with superior mechanical properties which was uniformly coated by PPS membrane on both sides of a glass fiber woven fabric (GFWF) using the TIPS membrane scraping method. The ratio of Benzoin (BZ) and Benzophenone (DPK) in casting solution were adjusted to control the surface structure of composite membrane, which was systematically characterized. The results revealed that when the casting solution contained 25 % DPK, the composite membrane supported by GFWF reached a tensile strength of 207.84 N, 31 times stronger than that of PPS membrane. When the casting solution contained 10 % DPK, the pure water flux of PPS/GFWF microfiltration membrane was 75.3 L⋅m−2⋅h−1⋅bar−1, 1.75 times higher than that of PPS membrane.

Robust design of durable PTFE/graphene hollow fiber composite membrane for high-temperature lubricant recycling

Nowadays, the lubricant recycling becomes difficult due to its complex composition and high viscosity. Reinforced hollow fiber membranes (HFM) have been widely used in various separation fields due to their controllable separation accuracy, large specific area, backwashability, as well as low operation and maintenance requirements. Herein, a durable polytetrafluoroethylene (PTFE)/graphene (GE) hollow fiber composite membrane (HFCM) with high temperature resistance was designed through the laminated-sintering process to solve the lubricant issue. The membrane featured a solid three-layer reinforced structure and compared with the pure GE membrane, the adverse effects from GE brittleness are efficiently avoided, which ultimately improved the membrane flexibility and morphological stability. Moreover, this PTFE/GE HFCMs showed superior high-temperature resistance and lipophilicity with an oil contact angle of 0°. With a reasonable regulation of lubricant temperature and GE content, the membrane flux exceeded 917 L·m−2·h−1·bar−1 and stabilized at 458 L·m−2·h−1·bar−1 after 12 h of membrane operation at 150 °C. The membrane flux remained at a relatively high level of 103 L·m−2·h−1·bar−1 after four cycles, with a flux recovery over 83 %. In addition, the membrane separation-efficiency up to 99.02 % for activated carbon in lubricants. Overall, the PTFE/GE HFCMs presented great potential for recycling lubricants or other heavy crude oils at high temperatures.

Electrospun the oriented silk fibroin/ bioactive glass @ silk fibroin/ polycaprolactone composite bi-layered membranes for guided bone regeneration

Guided bone regeneration (GBR) technology has been extensively used in the treatment of alveolar bone defects. However, existing GBR membranes still have great shortcomings in terms of biological activity and regeneration potential. In order to improve the performance of existing GBR membranes, based on the principle of GBR, this study starts from two aspects of material and structure, adding BG particles with good biological properties and introducing directional structure to construct a new type of double-layer composite fiber membrane, which can not only achieve the barrier function, but also induce the directional migration and differentiation of osteoblasts, so as to play the role of bone tissue regeneration and repair more efficiently. In this study, a bi-layer composite GBR membrane with oriented structure of silk fibroin (SF) / bioactive glass (BG) @ silk fibroin (SF) / polycaprolactone (PCL) was prepared by high-speed electrospinning technology, which achieved the dual functions of bone regeneration and barrier. The morphology, mechanical properties, secondary structure, biocompatibility and bioactivity of the oriented bi-layer composite membranes were studied systematically. The results showed that the fiber diameter and the pore size of SF/PCL composite membranes were obviously smaller than that of SF/BG composite membranes. Compared with SF and SF/BG composite membranes, the Young's modulus and tensile stress of the oriented SF/BG composite membranes is significantly increased, but the elongation at break is relatively decreased. The water contact angle of the material significantly decreased after the addition of BG particles and the introduction of orientated structure, which greatly improved the hydrophilicity of the composite membranes. Furthermore, the oriented SF/BG@SF/PCL exhibited higher cell adhesion and proliferation compared with the disordered SF/BG fiber membranes, and the introduction of BG particles significantly enhanced osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Besides, the barrier effect of the SF/PCL membrane was verified by L929 cells. The relatively dense structure leads to a good barrier effect as well as the obvious proliferation on the cells. This bi-layer composite SF/BG@SF/PCL membrane is a competitive candidate in the field of GBR technology and bone regeneration.

Regulation of TiO2 @PVDF piezoelectric nanofiber membranes on osteogenic differentiation of mesenchymal stem cells

Bioactive piezoelectric materials with similar properties as natural bone tissue with piezoelectricity have been explored for bone repair. Polyvinylidene fluoride (PVDF) is among the most studied piezoelectric polymers and has been manifested to promote osteogenic differentiation. Unfortunately, in the practical application of bone repair, bioactive materials as implants have faced poor electrical signal stability and poor modulation of bone regeneration, which have seriously hindered their further development. Here, we fabricated a composite piezoelectric fibrous membrane with titanium dioxide (TiO2) nanoparticles and PVDF (TiO2 @PVDF) for cellular osteogenic differentiation. The expression quantity of the gene osteocalcin (OCN) with the piezoelectric fibrous membrane was 49 times and 6 times higher than the expression quantity of OCN with the control group and with the pure polyvinylidene fluoride (PVDF), respectively. Moreover, the membrane with 0.3 wt% TiO2 (P-0.3TN) generated high surface potential and significantly promoted cell adhesion and proliferation through electromechanical stimulation early in osteogenic differentiation. Alkaline phosphatase (ALP) activity was increased up to 2-fold by stimulation of electrical and mechanical signals through piezoelectric fibers, effectively inducing osteogenic differentiation at the early stage. The proposed mechanism of regulating osteogenic differentiation behavior by the surface potential of TiO2 @PVDF piezoelectric fiber composite membrane provides guidance for designing electroactive materials to promote osteogenic differentiation and bone regeneration and remodeling.