Double-layered Membrane Research Articles

Molecular dynamics study on electric field-facilitated separation of H2O/O2 through nanoporous graphene oxide membrane

The application of external stimuli, such as electric fields, could improve gas separation. Molecular dynamics (MD) simulations were conducted to analyze the dynamic electric field-facilitated separation process of H2O/O2 gas molecules through a double-layered nanoporous graphene oxide membrane. The computational results illustrated an enhanced gas permeation rate of 3.26 × 103 mol·m−2·s−1 for H2O molecules with an external electric field of 10−4 V·Å−1, and an enhanced selectivity of 1.44 over O2 molecules, which was 0.33 in the absence of the external electric field. The mechanism of enhanced H2O/O2 separation has also been illuminated by examining the variation in interaction energy with electric field strength. The electric field inhibits the hydrogen bond interactions between H2O molecules and H2O membranes. Accelerating desorption under electric fields would enable more adsorption sites on the membrane, thereby facilitating H2O molecules permeation.

Rapid development of a subunit nano-vaccine against drug-resistant Pseudomonas aeruginosa with effective cross-protection

The complex antigen composition and limited selection of adjuvants restricted the development of Pseudomonas aeruginosa (P. aeruginosa) subunit vaccines. The evolvement of multiple serotypes of P. aeruginosa also challenges current vaccine candidates due to their poor cross-protection capacity. Herein, we first report a facile strategy to prepare comprehensive antigens loaded nano-vaccines for the rapid development of a P. aeruginosa vaccine with a highly effective cross-protection capacity. Namely, cytosolic antigens derived from bacterial lysates (BL) of PAO1, a drug-resistant P. aeruginosa, were loaded in the mesoporous silica nanospheres (MSNs), while membrane antigens derived from double-layered membrane vesicles (DMVs) of PAO1 were further fused on MSNs surface. The engineered MSN-BL@DMV showed a clear core-shell morphology, and it significantly promoted cellular internalization and maturation of dendritic cells without additional adjuvants. After subcutaneous vaccination, MSN-BL@DMV prepared from PAO1 efficiently migrated to lymph nodes, potently induced the humoral and cellular immune responses with exquisite specificity, and substantially protected mice from the challenge of PAO1 and another drug-resistant P. aeruginosa (PA-XN-1). In summary, the MSNs-based comprehensive antigen delivery system successfully protected mice from different strains of P. aeruginosa infection, providing new insights for treatment of other refractory pathogen infections.

Advances in the Application of Exosomes Identification Using Surface-Enhanced Raman Spectroscopy for the Early Detection of Cancers

Exosomes are small nanoscale vesicles with a double-layered lipid membrane structure secreted by cells, and almost all types of cells can secrete exosomes. Exosomes carry a variety of biologically active contents such as nucleic acids and proteins, and play an important role not only in intercellular information exchange and signal transduction, but also in various pathophysiological processes in the human body. Surface-enhanced Raman Spectroscopy (SERS) uses light to interact with nanostructured materials such as gold and silver to produce a strong surface plasmon resonance effect, which can significantly enhance the Raman signal of molecules adsorbed on the surface of nanostructures to obtain a rich fingerprint of the sample itself or Raman probe molecules with ultra-sensitivity. The unique advantages of SERS, such as non-invasive and high sensitivity, good selectivity, fast analysis speed, and low water interference, make it a promising technology for life science and clinical testing applications. In this paper, we briefly introduce exosomes and the current main detection methods. We also describe the basic principles of SERS and the progress of the application of unlabeled and labeled SERS in exosome detection. This paper also summarizes the value of SERS-based exosome assays for early tumor diagnosis.

Simultaneously enhancing purification, catalysis and in situ separation in a continuous cross-flow catalytic degradation process of multi-component organic pollutants by a double-layer PVDF composite membrane

Organic pollutant degradation of waterbody by membrane catalysis is widely reported due to the low operation cost and high catalytic degradation efficiency. However, it still faces a great challenge to effectively treat the complicated wastewater with coexisting multi-component organic pollutants. Herein, we design and then fabricate a novel double-layer composite membrane to realize the separation of multi-component organic pollutants, selectively catalytic degradation and in situ product separation in a one-step. This double-layer membrane systematically characterized by FTIR, XPS, SEM, AFM and the other techniques, comprises a top semi- interpenetrating polymer network(semi-IPN) layer and a bottom poly(vinylidene fluoride)-Pd catalytic layer. In a continuous cross-flow filtration process, some pollutants such as congo red, direct black 38, direct red 23 and BSA are directly separated by the membrane, while the pollutant p-nitrophenol controllably penetrates through the top semi-IPN layer and then reacts in the catalytic layer; subsequently, the product p-aminophenol is in situ separated and collected. In this process, the pollutant p-nitrophenol is purified by filtration in advance; further, the product is isolated by the top layer and timely dischared out by penetrative flow. Therefore, this process prevents the undesired pollutants and products from interfering the catalytic degradation of the catalytic layer. Thus, degradation reaction can continuously and conveniently proceed, companying with products in situ separation and collection.

Transition sandwich Janus membrane of cellulose acetate and polyurethane nanofibers for oil–water separation

Through sequential electrospinning, a sandwich Janus membrane (PU-(CA/PU)-CA) was constructed with hydrophobic polyurethane (PU) nanofiber membrane as the top layer, cellulose acetate/polyurethane (CA/PU) blend nanofiber membrane as the intermediate transition layer and hydrophilic cellulose acetate (CA) nanofiber membrane as the bottom layer. The effects of membrane structure, composition and thickness on the mechanical properties, permeability and separation ability of PU-(CA/PU)-CA nanofiber membrane were studied. The results show that the transition sandwich structure PU-(CA/PU)-CA membrane has good mechanical properties, high permeability and selective separation ability, and can realize the unidirectional transmission of water and efficient oil–water separation. When the membrane thickness is 80 μm, the hydraulic permeability is 3.4 ± 0.4 × 104 L/(m2 h bar), the oil–water separation efficiency reaches 99 ± 0.4%, and the tensile strength is 95.8% higher than that of the double-layer PU-CA membrane. The thermal stability and antifouling ability of PU-(CA/PU)-CA nanofiber membrane have also been improved, and the reusability is good. CA/PU transition interlayer improves the interfacial compatibility between CA and PU nanofiber membrane, enhances the performance of PU-(CA/PU)-CA nanofiber Janus membrane, and shows its application prospect in the field of separation and purification.Graphical abstract

Effect of Instructional Package on Knowledge and Practices Regarding Care of the Patients with Intercoastal Drainage among Staff Nurses in Selected Hospitals

Introduction: Lungs are the vital organs for respiration. The lungs are covered by a double-layered serous membrane called pleura. The space between the pleura contains pleural fluid which helps in lubrication and prevents friction between the lungs and chest wall. Intercostal drain is a flexible plastic tube that is inserted through the chest wall into the pleural space. It is used to remove air, fluid, and pus from the intrathoracic space. Apatient may require an intercoastal drainage system at any time when the negative pressure in the pleural cavity is disrupted, resulting in respiratory distress. Aims: The aim of the study was to assess the effect of instructional package on knowledge and practices regarding care of the patients with intercoastal drainage among staff nurses in selected hospitals. Materials and Methods: A descriptive evaluatory research approach with one group pre-test post-test research design was used for the study. The sample comprised 50 staff nurses who fulfilled the inclusion criteria, using non-probability convenient sampling technique. Data were analyzed using descriptive and inferential statistics. Results: We observed that knowledge and practices measured after instructional package was significant (P < 0.05). There were association of knowledge with age, department, and qualification and for practices association found with age and qualification, respectively. Conclusion: Instructional package was effective measured to improve knowledge and practices regarding care of the patients with intercoastal drainage among staff nurses in selected hospitals.

Novel biomarker and drug delivery systems for theranostics – extracellular vesicles

Abstract Extracellular vesicles (EVs) are nano- and micro-sized double-layered membrane entities derived from most cell types and released into biological fluids. Biological properties (cell-uptake, biocompatibility), and chemical (composition, structure) or physical (size, density) characteristics make EVs a good candidate for drug delivery systems (DDS). Recent advances in the field of EVs (e.g., scaling-up production, purification) and developments of new imaging methods (total-body positron emission tomography [PET]) revealed benefits of radiolabeled EVs in diagnostic and interventional medicine as a potential DDs in theranostics.

Enhanced Proton Conductivity of (3-mercaptopropyl)trimethoxysilane—Grafted Graphene Oxide Membranes for Hydrogen Fuel Cells

Graphene oxide membrane (GOM) is an excellent proton conductor under humidified conditions and can be suited to various electrochemical devices, including proton exchange membrane fuel cells (PEMFCs). Conventional PEMFCs are based on Nafion®, a commercial perfluorocarbon sulfonic acid (PSA) ionomer that has many disadvantages, such as high cost, strenuous synthesis process, and fuel crossover. To minimize these deficiencies, a low-cost, alternative, environmental friendliness, and highly proton conductive membrane was synthesized. Here, GOM is considered the base electrolyte of PEM. However, the proton conductivity of GOM shows a very large orientation dependence. In particular, due to the two-dimensional structure of graphene oxide, the through-plane direction of GOM is inevitably oriented in c-axis, and its conductivity is significantly lower than that of Nafion®. In this study, (3-mercaptopropyl)trimethoxysilane (MPTS, HS(CH2)3Si(OCH3)3) was reacted with the surface of graphene oxide particles and then oxidizes to provide a fast proton conduction path through the obtained sulfonic acid groups. That is, MPTS binds to the surface of graphene oxide (GO) through hydrolysis (Si–OCH3 to Si–OH) and condensation (Si–OH to Si–O–C), and the thiol group of MPTS is converted to sulfonic acid ligands through oxidation. FTIR and XPS spectra successfully confirmed the MPTS bound on the surface of GOM. The resulting MPTS-modified GOM (M-GOM) shows an enormous increase in proton conductivity (Th-plane) compared to GOM, but not much as high as Nafion®. The ion exchange capacity, proton conductivity, gas leakage, mechanical properties, thermal stability, electrochemical properties, and physico-chemical properties of M-GOM as electrolytes are measured and compared with GOM and Nafion®. Hydrogen fuel cells using M-GOM alone and a double-layered membrane composed of M-GOM and Pd thin films as electrolytes are built and their operating characteristics are reported.

Depth filtration application of nanofibrillated cellulose-mesoporous silica nanoparticle composites as double-layer membranes

The adsorption capacity of cellulose membranes without modification is negligible for water treatment. Therefore, enhancing cellulose adsorption capacity via cost-effective approaches is required. Double-layer membranes with a nanofibrillated cellulose (NFC) membrane and an in-situ produced NFC-mesoporous silica nanoparticles (MSN) depth filter layers were produced. The membranes were tailored to improve size rejection and saturated adsorption capacity (SAC) by altering the gram per meter square (gsm) of the depth filter layer. The higher SAC of double-layer membranes was achieved by increasing the depth filter layer gsm and because of the significantly lower porosity of double-layer membranes compared to NFC-MSN single-layer membranes. The optimized membrane for methylene blue (MB) showed the SAC of 107 mg per g of MSN. The membrane could be modified with polyethyleneimine (PEI) or polyamide amine-epichlorohydrin (PAE) resin as cationic charged polyelectrolytes for the selective adsorption of anionic molecules of metanil yellow (MY). The membrane modified with PEI had 41 times higher SAC than unmodified specimens toward MY. Optimized double-layer membranes for size rejection, including 30 gsm composite layer, were produced by reducing the NFC fibre diameter via higher homogenization and drying the NFC layer before adding the depth filter layer. The optimized double-layer membrane had a polyethylene glycol (PEG) molecular weight cut-off (MWCO) of 200 kDa. These membranes manufactured by cost-effective materials have great potential of scale-up for membrane manufacturing for water treatment. The combination of good adsorption and size rejection makes a unique material that should be explored further.

Proteomic analysis of serum and serum exosomes, and their application in intrahepatic cholangiocarcinoma

外泌体是由各种类型细胞在正常或非正常生理情况下分泌释放至细胞外且携带多种生物活性分子的细胞外囊泡,在细胞间通讯和免疫应答等生物过程中发挥着重要作用。肝内胆管癌是一种胆道上皮恶性肿瘤,早期无明显临床症状且生存率较低,目前常用的诊断手段包括依赖于影像设备的诊断方式和灵敏度及特异性较低的诊断标志物等,这些手段的不足对发展新的特异性标志物提出了需求。该文对血清中的外泌体进行了分离和表征,并采用液相色谱-质谱技术针对健康组与肝内胆管癌患者组的血清样本和血清外泌体样本进行了无标记定量蛋白质组学分析,分别从两种类型样本中鉴定并筛选到271和430种可信蛋白质。基于血清样本和血清外泌体样本的可信蛋白质定量表达值进行多维统计分析都能将健康组与肝内胆管癌患者组良好地区分开。对血清样本中鉴定到的蛋白质进行差异蛋白质筛选,肝内胆管癌患者组相对于健康组有15个上调和8个下调蛋白质;对血清外泌体样本中鉴定到的蛋白质进行差异蛋白质筛选,肝内胆管癌患者组相对于健康组有33个上调和18个下调蛋白质;基于两种样本筛选到的差异蛋白质中仅有4个是重复的,且基于血清外泌体样本的51个差异蛋白质中有35个蛋白质属于外泌体蛋白质数据库。针对差异蛋白质进行生物学信息分析,与差异蛋白质相关的分子功能、生物过程和信号通路主要涉及天然免疫反应、炎症反应和凝血等过程。该研究为发现肝内胆管癌的潜在生物标志物和探究肝内胆管癌的发生、发展和转移等过程提供了参考和借鉴价值。此外,通过比较研究发现血清外泌体样本能够获得较多的差异蛋白质和生物学信息,证明了外泌体作为组学分析样本的价值和应用潜力。

A bio-inspired nanocomposite membrane with improved light-trapping and salt-rejecting performance for solar-driven interfacial evaporation applications

Solar-driven interfacial water evaporation is a rapid emerging technology to address the global water crisis. Efficient solar absorption as well as robust salt-rejecting performance are among the critical requirements of this technology. Here, we report a novel double-layered nanocomposite membrane with improved solar absorption capability while simultaneously achieving enhanced salt-rejecting performance for solar-driven interfacial evaporation applications, such as seawater purification. Two bio-inspired material engineering strategies are utilized: first, inspired by black butterfly wings, a top sublayer based on MXene nanostructures is utilized to reduce light reflection and thereby improve its photo-thermal efficiency. Secondly, inspired by the selective mass transport capability of plant root cells, a bottom sublayer based on reduced graphene oxide (rGO) nanosheets with similar characteristics is designed and fabricated. The narrowed interlayer spacing between adjacent rGO nanosheets is demonstrated to effectively transport water molecules while rejecting salt ions. Finally, the nanocomposite MXene@rGO membrane achieves an evaporation rate of 1.33 kg m −2 h −1 and efficiency of 85.2% at 1 Sun. And the efficiency maintains 81.4% after 40 cycles of testing in seawater. In addition, simulations are performed to understand the light-trapping phenomenon for the MXene nanostructured surface. This bio-inspired work provides valuable insights for designing next-generation solar absorbers. • Inspired by black butterfly wings, parallel/wedge nanostructures are designed to reduce light reflection. • Inspired by the capability of plant root cells, a sublayer of rGO nanosheets is designed to selectively transport water molecules and salt ions. • FTDT simulation of normalized electric field intensity is performed to understand the origin of light trapping.

Extracellular Vesicles from Human Urine-Derived Stem Cells Ameliorate Particulate Polyethylene-Induced Osteolysis.

PurposeWear debris particle-induced periprosthetic osteolysis is a severe complication of total joint replacement that results in aseptic loosening and subsequent arthroplasty failure. No effective therapeutic agents or drugs have been approved to prevent or treat osteolysis; thus, revision surgery is often needed. Extracellular vesicles (EVs) are vital nanosized regulators of intercellular communication that can be directly applied to promote tissue repair and regeneration. In this study, we assessed the therapeutic potential of EVs from human urine-derived stem cells (USCs) (USC-EVs) in preventing ultrahigh-molecular-weight polyethylene (UHMWPE) particle-induced osteolysis.MethodsUSCs were characterized by measuring induced multipotent differentiation and flow cytometry. USC-EVs were isolated and characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS) and Western blotting. RAW264.7 cells and bone marrow mesenchymal stem cells (BMSCs) were cultured with USC-EVs to verify osteoclast differentiation and osteoblast formation, respectively, in vitro. The effects of USC-EVs were investigated on a UHMWPE particle-induced murine calvarial osteolysis model by assessing bone mass, the inflammatory reaction, and osteoblast and osteoclast formation.ResultsUSCs differentiated into osteogenic, adipogenic and chondrogenic cells in vitro and were positive for CD44, CD73, CD29 and CD90 but negative for CD34 and CD45. USC-EVs exhibited a cup-like morphology with a double-layered membrane structure and were positive for CD63 and TSG101 and negative for calnexin. In vitro, USC-EVs promoted the osteogenic differentiation of BMSCs and reduced proinflammatory factor production and osteoclastic activity in RAW264.7 cells. In vivo, local injection of USC-EVs around the central sites of the calvaria decreased inflammatory cytokine generation and osteolysis compared with the control groups and significantly increased bone formation.ConclusionBased on our findings, USC-EVs prevent UHMWPE particle-induced osteolysis by decreasing inflammation, suppressing bone resorption and promoting bone formation.

Thermal environment analysis of enclosed dome with double-layered PTFE fabric roof integrated with aerogel-glass wool insulation mats: On-site test and numerical simulation

To study the thermal performance of an enclosed dome with double-layered PTFE membrane with aerogel-glass wool insulation mats, a comprehensive on-site test was carried out. Twenty-two wireless thermometers were used to monitor the temperature of key positions during a clear to cloudy day in summer. Solar irradiance was recorded as well. A numerical model was established to compare the thermal insulation property of this case and other three cases with different thermal insulations for double-layered membrane roof containing no extra insulation, peripheral wool glass insulation and all aerogel insulation. These cases only differ in the occupation area of thermal insulation materials laid on inner membrane. On-site test illustrates that the novel roof with aerogel- glass wool insulation can effectively prevent ambient radiation to pass through and render the stands insusceptible to the sunlight in regardless of the incidence angle. The temperature field of the dome is stratified and temperature only varies in vertical direction. According to numerical analysis, the current roof performs best in terms of thermal insulation property. This roof with combined insulation can reduce the average temperature difference of outdoor and indoor space by 7.7 ℃ while the value is merely 7.0 ℃, 5.9 ℃ and 4.8 ℃ for under the same environment condition.

Polymeric Nanoparticles for Mitochondria Targeting Mediated Robust Cancer Therapy.

Despite all sorts of innovations in medical researches over the past decades, cancer remains a major threat to human health. Mitochondria are essential organelles in eukaryotic cells, and their dysfunctions contribute to numerous diseases including cancers. Mitochondria-targeted cancer therapy, which specifically delivers drugs into the mitochondria, is a promising strategy for enhancing anticancer treatment efficiency. However, owing to their special double-layered membrane system and highly negative potentials, mitochondria remain a challenging target for therapeutic agents to reach and access. Polymeric nanoparticles exceed in cancer therapy ascribed to their unique features including ideal biocompatibility, readily design and synthesis, as well as flexible ligand decoration. Significant efforts have been put forward to develop mitochondria-targeted polymeric nanoparticles. In this review, we focused on the smart design of polymeric nanosystems for mitochondria targeting and summarized the current applications in improving cancer therapy.

Mitochondrial Metal Ion Transport in Cell Metabolism and Disease.

Mitochondria are vital to life and provide biological energy for other organelles and cell physiological processes. On the mitochondrial double layer membrane, there are a variety of channels and transporters to transport different metal ions, such as Ca2+, K+, Na+, Mg2+, Zn2+ and Fe2+/Fe3+. Emerging evidence in recent years has shown that the metal ion transport is essential for mitochondrial function and cellular metabolism, including oxidative phosphorylation (OXPHOS), ATP production, mitochondrial integrity, mitochondrial volume, enzyme activity, signal transduction, proliferation and apoptosis. The homeostasis of mitochondrial metal ions plays an important role in maintaining mitochondria and cell functions and regulating multiple diseases. In particular, channels and transporters for transporting mitochondrial metal ions are very critical, which can be used as potential targets to treat neurodegeneration, cardiovascular diseases, cancer, diabetes and other metabolic diseases. This review summarizes the current research on several types of mitochondrial metal ion channels/transporters and their functions in cell metabolism and diseases, providing strong evidence and therapeutic strategies for further insights into related diseases.

Emerging Exosomes and Exosomal MiRNAs in Spinal Cord Injury.

Acute spinal cord injury (SCI) is a serious traumatic event to the spinal cord with considerable morbidity and mortality. This injury leads to short- and long-term variations in the spinal cord, and can have a serious effect on the patient’s sensory, motor, or autonomic functions. Due to the complicated pathological process of SCI, there is currently no successful clinical treatment strategy. Exosomes, extracellular vesicles (EVs) with a double-layer membrane structure of 30–150 nm diameter, have recently been considered as critical mediators for communication between cells and tissues by transferring proteins, lipids, and nucleic acids. Further studies verified that exosomes participate in the pathophysiological process of several diseases, including cancer, neurodegenerative diseases, and cardiovascular diseases, and could have a significant impact in their treatment. As natural carriers of biologically active cargos, exosomes have emerged as pathological mediators of SCI. In this review article, we critically discuss the functions of exosomes as intracellular mediators and potential treatments in SCI and provide an outlook on future research.

Preparation and in vitro evaluation of forsythoside A-loaded exosomes

A drug delivery system of forsythoside A-loaded exosomes(FTA-Exos) with high biocompatibility and low immunogenicity was established to investigate its impact on the migration of human lung epithelial adenocarcinoma A549 cells. The exosomes from A549 cells were extracted and purified by ultra-high speed centrifugation and ultrafiltration. FTA-Exos were prepared by ultrasonic incubation, and characterized by particle size analysis, transmission electron microscopy, and Western blot assay. The uptake of FTA-Exos by A549 cells was observed under the laser confocal microscope, and the impact of FTA-Exos on the migration of A549 cells was investigated by cell scratch assay. The results showed that the average particle size of the prepared FTA-Exos was(138.90±2.37) nm, which increased slightly after drug loading. The PDI was 0.291±0.013, and the average potential was(-10.1±0.66) mV. The FTA-Exos were spheroidal in appearance as observed by transmission electron microscope, with an obvious saucer-like double-layer membrane. Western blot assay indicated that the specific proteins CD63 and Alix were both expressed in exosomes. The laser confocal microscopy suggested that FTA-Exos were taken up by A549 cells and stably maintained in the cell for 4-8 h, and the fluorescence was significantly enhanced at 4 h. The scratch assay showed that the inhibitory effect of FTA-Exos on the migration of A549 cells was significantly stronger than that of forsythoside A(P < 0.05). In conclusion, the drug delivery system of FTA-Exos established in this study had good stability, reliable preparation process, and potent inhibitory effect on the migration of A549 cells in vitro, which can provide an important reference for subsequent in-depth research and application.

Small extracellular vesicles from human adipose-derived mesenchymal stromal cells: a potential promoter of fat graft survival

BackgroundSmall extracellular vesicles (sEVs) with genetic information secreted by cells play a crucial role in the cellular microenvironment. In this study, our purpose is to explore the characteristics of the small extracellular vesicles of human adipose-derived mesenchymal stromal cells (hADMSC-sEVs) and studied the role of hADMSC-sEVs in improving the survival rate of grafted fat.MethodsIn the present study, we used the transmission electron microscopy, nano-tracking analysis, nanoflow surface protein analysis, and zeta potential value to identify sEVs. SEVs’ trajectory was traced dynamically to verify whether hADMSC-sEVs can be internalized into human umbilical vein endothelial cells (HUVECs) in vitro at different times. The angiogenic property of hADMSC-sEVs was observed by measuring the volume, weight, and histological analysis of the grafted fats in nude mouse models.ResultsOur research showed that the hADMSC-sEVs were sEVs with double-layer membrane structure and the diameter of which is within 30–150 nm. hADMSC-sEVs exert biological influence mainly through internalization into cells. Compared with the control group, the hADMSC-sEVs group had a significantly higher survival rate of grafted fat, morphological integrity, and a lower degree of inflammation and fibrosis. And immunohistochemistry showed that hADMSC-sEVs significantly increased the neovascularisation and the expression of CD34, VEGFR2, and Ki-67 in the graft tissue.ConclusionsAs a potential nanomaterial, hADMSC-sEVs have been explored in the field of cell-free application of stem cell technology. hADMSC-sEVs promoted the survival of grafted fats by promoting the formation of new blood vessels, which is another promising progress in the field of regenerative medicine. We believe that hADMSC-sEVs will have a broad application prospect in the field of regenerative medicine in the future.

In-situ growth of double-layered polyaniline composite membrane for organic solvent nanofiltration

• PANI composite OSN membrane with TFC structure fabricated by in-situ growth method. • Membrane performance optimization by adjusting in-situ polymerization parameters. • Excellent ethanol permeance and dye rejection due to double-layered PANI structure. • Excellent chemical and physical stabilities of PANI composite OSN membrane. • Excellent long-term stability and anti-fouling ability during 12 h filtration. The trade-off between permeability and rejection limits the widespread application of organic solvent nanofiltration (OSN) membrane. As a promising membrane materials, polyaniline (PANI) has drawn increasing attention owing to its easy synthesis and excellent chemical stability. Nowadays, the reported PANI-based OSN membranes were fabricated by phase inversion process together with chemical crosslinking treatment. In this work, a novel double-layered polyaniline (PANI) composite OSN membrane was firstly developed through in-situ polymerization of aniline onto hydrolyzed polyacrylonitrile (HPAN) porous substrate. The separation performances of PANI/HPAN composite membrane were optimized by varying aniline concentration, polymerization time and oxidant:aniline ratio. The double-layered PANI/HPAN composite membrane prepared with 0.2 M aniline, 1 h polymerization and 1:4 oxidant:aniline ratio displayed ethanol permeance of 14.9 L∙m −2 ∙h −1 ∙bar −1 and rose bengal rejection of 98.1%. The membrane performance with the solvents including methanol, isopropanol, 1-butanol, acetone, n-hexane, and toluene were also tested, showing a molecular weight cut-off (MWCO) of 500 ∼ 600 g∙mol −1 . In addition, the double-layered PANI/HPAN composite membrane maintained excellent and stable performance under strong acid soaking, ultrasonic vibration and continuous filtration

Effects of double layer membrane loading eugenol on postharvest quality of cucumber

We prepared double layer membranes containing eugenol (0.2, 0.3, and 0.4 g/100 g) using electrospinning technology and investigated their effects on the postharvest quality of cucumbers. The poly (lactic acid) (PLA) membrane was attached to the collector, and the nanofibers were prepared using an electrospinning device and deposited on the surface of the PLA membrane to form double layer membrane. The results informed that the shelf life of cucumbers packaged with double layer membranes increased from 15 days to 21 days at 4 °C. The double layer membrane containing 0.3 g/100 g eugenol had greater effects on delaying the spoilage process and prolonging the shelf life of cucumber fruits than other membrane. Compared with unpackaged samples, packaged samples had higher hardness values, Peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) enzyme activities, and protein and proline content; and they had lower weight loss, skin color differences values, stickiness values, microbial growth, and malondialdehyde (MDA) and total soluble sugar content. Our results suggest that double layer membranes may be used to extend the shelf life of cucumbers at 4 °C.