Trilayer Membrane Research Articles

Sacrificial MoS2-Polyelectrolyte membranes for fouling control in nanofiltration and reverse osmosis

Sacrificial membranes have emerged as a promising solution to mitigate membrane fouling through their ability to be removed and regenerated while preserving membrane integrity and performance. In this study, we synthesized sacrificial trilayers on a commercial polyamide nanofiltration membrane using layer-by-layer (LbL) assembly of two-dimensional molybdenum disulfide (MoS2) nanosheets and polyelectrolytes. Quartz crystal microbalance with dissipation (QCM-D) studies showed the trilayers to be MoS2-dominant by mass and have a total areal density of 2.37 μg/cm2 after the deposition of two trilayers. The trilayer membrane showed a slight decrease in water permeability and an increase in calcium chloride rejection compared to the pristine nanofiltration membrane. The trilayer membrane demonstrated improved organic fouling resistance over the pristine nanofiltration membrane, maintaining permeability throughout six consecutive cycles. Interestingly, the trilayer membrane after gypsum scaling exhibited sacrificial layer removal and permeability recovery with simple hydraulic cleaning. This suggests the potential for membrane regeneration and sustained fouling resistance that may be achieved by utilizing disruptive interactions with the trilayer materials. In conclusion, sacrificial membranes made of MoS2 nanosheets and polyelectrolytes exhibited excellent organic and inorganic fouling resistance and promising potential for layer removal and regeneration.

New insights into the destabilization of fat globules in ultra-instantaneous UHT milk induced by added plasmin: Molecular mechanisms and the effect of membrane structure on plasmin action

Residual plasmin activity in whole ultra-instantaneous UHT (UI-UHT) milk causes rapid fat rise during storage, seriously affecting consumers' purchase intentions. In this work, the molecular mechanisms underlying fat destabilization in whole UI-UHT milk by added plasmin were investigated based on the hydrolysis behavior of interfacial proteins. By using SDS-PAGE and peptidomic analysis, we found that the hydrolysis of interfacial proteins by plasmin led to a decrease in the amount and coverage of interfacial proteins and an increase in zeta-potential value, causing the flocculation and coalescence of fat globules. Moreover, the hydrolysis pattern varied in different categories of interfacial proteins by plasmin. In total, 125 peptides in all samples were identified. Plasmin tended to hydrolyze most major milk fat globule membrane (MFGM) proteins into protein fragments (>10 kDa) rather than peptides (<10 kDa). In contrast, peptides derived from caseins were more preferentially identified within a relatively short incubation time. It was the co-hydrolysis of caseins and some major MFGM proteins as anchors that destroyed the stability of MFGM. Furthermore, studies on the effect of trilayer membrane structure remaining at the interface on the hydrolysis rate of major MFGM proteins by plasmin revealed that ADPH and BTN were very sensitive to plasmin action, while PAS 7 was very resistant to plasmin action. Overall, membrane structure reduced the susceptibility of some major MFGM proteins to plasmin and provided protective effects. Therefore, this study provided important insights into the hydrolysis behavior of interfacial proteins in whole UI-UHT milk induced by plasmin.

Tri-layer amniotic membrane allografts: a versatile scaffold for managing acute and hard-to-heal wounds.

Tri-layer amniotic membrane allografts: a versatile scaffold for managing acute and hard-to-heal wounds.

Highly efficient vanadium redox flow batteries enabled by a trilayer polybenzimidazole membrane assembly

AbstractA novel polybenzimidazole (PBI)‐based trilayer membrane assembly is developed for application in vanadium redox flow battery (VRFB). The membrane comprises a 1 µm thin cross‐linked poly[2,2′‐(p‐oxydiphenylene)−5,5′‐bibenzimidazole] (OPBI) sandwiched between two 20 µm thick porous OPBI membranes (p‐OPBI) without further lamination steps. The trilayer membrane demonstrates exceptional properties, such as high conductivity and low area‐specific resistance (ASR) of 51 mS cm−1 and 81 mΩ cm2, respectively. Contact with vanadium electrolyte increases the ASR of trilayer membrane only to 158 mΩ cm2, while that of Nafion is 193 mΩ cm2. VO2+ permeability is 2.73 × 10−9 cm2 min−1, about 150 times lower than that of Nafion NR212. In addition, the membrane has high mechanical strength and high chemical stability against VO2+. In VRFB, the combination of low resistance and low vanadium permeability results in excellent performance, revealing high Coulombic efficiency (&gt;99%), high energy efficiency (EE; 90.8% at current density of 80 mA cm−2), and long‐term durability. The EE is one of the best reported to date.

Bio-inspired polyionic membrane for long-lasting and repeatable electricity harvesting from moisture

Evaporation power generation (EPG), hailed as a promising clean power generation technology, has garnered significant attention. Nonetheless, achieving consistent and replicable performance of EPG remains a major challenge, hampering its practical application potential. Herein, we present the design of a tri-layered poly-ionic membrane (TL-PIM) inspired by transpiration processes in plants, that can not only continuously output electricity with an average voltage of ∼0.6 V for over 8 consecutive days with a maximum power density of 1.6 µW cm−2, but can also be reused for at least 70 cycles (> 350 h) with a stable voltage, demonstrating superior repeatability over most previous works. The excellent long-lasting and repeatable performance of EPG in the TL-PIM can be attributed to the stable nanochannels constructed by a hydrophilic polymer, 2D nanosheets, and poly-ionic liquids (PILs), where the bromide ions (Br-) in the PILs can shuttle back and forth selectively and efficiently during the power generation and discharge processes. More importantly, the TL-PIM can be integrated linearly to generate electricity within a wide range of temperatures and humidity, even outdoors, showcasing remarkable environmental adaptability. These findings on EPG indicate that the bio-inspired TL-PIM offers a promising venue for continuous and reproducible electricity generation by harnessing thermal energy from moisture, which holds significance for the sustainable utilization of EPG as a renewable energy source in the future.

Electrospun nanofiber-based tri-layer separators with CuO/TiO2 nanowires for high-performance and long-cycle stability of lithium-ion batteries

The tri-layer nanofiber membranes of (PAN containing CuO/TiO2 nanowires) / (PVDF-HFP + PMMA) / (PAN containing CuO/TiO2 nanowires) as separator in lithium-ion battery were manufactured by electrospinning technique. PVDF-HFP with excellent mechanical properties hinders the mobility of lithium ions because of its high crystallinity. By blending the amorphous PMMA polymer with PVDF-HFP, the crystallinity of PVDF-HFP + PMMA composite nanofiber was lowered, while high mechanical strength was maintained due to the dipole–dipole interaction between two polymers. The (PVDF-HFP + PMMA) nanofiber membrane was employed as the middle layer. The PAN nanofiber membranes containing CuO/TiO2 nanowires were prepared as top and bottom layers. The electrochemical properties and performance of the manufactured tri-layer membrane were evaluated, and it showed superior performance than polyolefin-based membranes. The tri-layer membrane maintained stable voltage changes for 700 h during galvanostatic cycling. Furthermore, it exhibited excellent performance in terms of rate capability and life cycle performance. The PE separator maintained a capacity retention of 67 % after 400 cycles, while the tri-layer membrane separator showed a capacity retention of 87 %. These results suggest the potential utility of tri-layer membrane separators as high-performance separators required in the lithium-ion battery.

Aloe vera mucilage loaded gelatin electrospun fibers contained in polylactic acid coaxial system and polylactic acid and poly(e-caprolactone) tri-layer membranes for tissue engineering.

Polymeric electrospun mats have been used as scaffolds in tissue engineering for the development of novel materials due to its characteristics. The usage of synthetic materials has gone in decline due to environmental problems associated with their synthesis and waste disposal. Biomaterials such as biopolymers have been used recently due to good compatibility on biological applications and sustainability. The purpose of this work is to obtain novel materials based on synthetic and natural polymers for applications on tissue engineering. Aloe vera mucilage was obtained, chemically characterized, and used as an active compound contained in electrospun mats. Polymeric scaffolds were obtained in single, coaxial and tri-layer structures, characterized and evaluated in cell culture. Mucilage loaded electrospun fibers showed good compatibility due to formation of hydrogen bonds between polymers and biomolecules from its structure, evidenced by FTIR spectra and thermal properties. Cell viability test showed that most of the obtained mats result on viability higher than 75%, resulting in nontoxic materials, ready to be used on scaffolding applications. Mucilage containing fibers resulted on materials with potential use on scaffolding applications due to their mechanical performance and cell viability results.

Hierarchical nanofibrous and recyclable membrane with unidirectional water-transport effect for efficient solar-driven interfacial evaporation

Solar-driven interfacial evaporation technology has attracted significant attention for water purification. However, design and fabrication of solar-driven evaporator with cost-effective, excellent capability and large-scale production remains challenging. In this study, inspired by plant transpiration, a tri-layered hierarchical nanofibrous photothermal membrane (HNPM) with a unidirectional water transport effect was designed and prepared via electrospinning for efficient solar-driven interfacial evaporation. The synergistic effect of the hierarchical hydrophilic-hydrophobic structure and the self-pumping effect endowed the HNPM with unidirectional water transport properties. The HNPM could unidirectionally drive water from the hydrophobic layer to the hydrophilic layer within 2.5 s and prevent reverse water penetration. With this unique property, the HNPM was coupled with a water supply component and thermal insulator to assemble a self-floating evaporator for water desalination. Under 1 sun illumination, the water evaporation rates of the designed evaporator with HNPM in pure water and dyed wastewater reached 1.44 and 1.78 kg·m−2·h−1, respectively. The evaporator could achieve evaporation of 11.04 kg·m−2 in 10 h under outdoor solar conditions. Moreover, the tri-layered HNPM exhibited outstanding flexibility and recyclability. Our bionic hydrophobic-to-hydrophilic structure endowed the solar-driven evaporator with capillary wicking and transpiration effects, which provides a rational design and optimization for efficient solar-driven applications.

Development of Bi- and Tri-Layer Nanofibrous Membranes Based on the Sulfated Polysaccharide Carrageenan for Periodontal Tissue Regeneration.

Periodontitis is a microbially-induced inflammation of the periodontium that is characterized by the destruction of the periodontal ligament (PDL) and alveolar bone and constitutes the principal cause of teeth loss in adults. Periodontal tissue regeneration can be achieved through guided tissue/bone regeneration (GTR/GBR) membranes that act as a physical barrier preventing epithelial infiltration and providing adequate time and space for PDL cells and osteoblasts to proliferate into the affected area. Electrospun nanofibrous scaffolds, simulating the natural architecture of the extracellular matrix (ECM), have attracted increasing attention in periodontal tissue engineering. Carrageenans are ideal candidates for the development of novel nanofibrous GTR/GBR membranes, since previous studies have highlighted the potential of carrageenans for bone regeneration by promoting the attachment and proliferation of osteoblasts. Herein, we report the development of bi- and tri-layer nanofibrous GTR/GBR membranes based on carrageenans and other biocompatible polymers for the regeneration of periodontal tissue. The fabricated membranes were morphologically characterized, and their thermal and mechanical properties were determined. Their periodontal tissue regeneration potential was investigated through the evaluation of cell attachment, biocompatibility, and osteogenic differentiation of human PDL cells seeded on the prepared membranes.

Differences in macrophage expression in induced membranes by fixation method – Masquelet technique using a mouse's femur critical-sized bone defect model

IntroductionMasquelet's induced membrane technique (MIMT) is an emerging method for reconstructing critical-sized bone defects. However, an incomplete understanding of the underlying biological and physical processes hinders further optimization. This study investigated the effect of different bone-defect fixation methods on macrophage expression in an induced membrane using a novel mouse plate-fixed Masquelet model. MethodsMice were divided into Plate-fixed Masquelet (P-M), Intramedullary-fixed Masquelet (IM-M), Plate-fixed Control (P-C), and Back subfascial (B) groups. In the P-M and IM-M groups, a polymethylmethacrylate (PMMA) spacer was implanted into a 3 mm bone defect, while the defect in the P-C group remained unfilled. In group B, a spacer was inserted under the back fascia to examine membrane formation caused by a simple foreign body reaction. Tissues were collected at 1, 2, and 4 weeks postoperatively. Hematoxylin and eosin (H&E) staining and immunohistochemistry (CD68 and CD163: macrophage markers) were performed to assess macrophage expression within the membrane. qPCR was performed to measure the expression of CD68, CD163, and fibroblast growth factor 2 (FGF2). ResultsFour weeks post-operation, the P-M group presented with minimal callus growth, whereas the IM-M group exhibited vigorous growth. The P-M and IM-M groups displayed a tri-layered membrane structure, which is consistent with the results of previous studies. The IM-M group had significantly thicker membranes, whereas the P-M group exhibited higher expression levels of CD68, CD163, and FGF2. Group P-C showed no osteogenesis, whereas group B maintained a thin, cell-dense membrane structure. The P-M group consistently showed higher gene expression levels than the P-C and P-B groups. ConclusionThis study introduced a mouse plate fixation model for MIMT. The induced membranes could be adequately evaluated in this model. Induced membranes are formed by foreign body reactions to PMMA spacers; however, their properties are clearly different from those of simple foreign body reaction capsules and granulation tissues that infiltrate bone defects, suggesting that they are more complex tissues. The characteristics and expression of macrophages within these induced membranes varied according to the bone defect fixation method.

Bioactive Functions of Lipids in the Milk Fat Globule Membrane: A Comprehensive Review.

The milk fat globule membrane (MFGM) is a complex tri-layer membrane that wraps droplets of lipids in milk. In recent years, it has attracted widespread attention due to its excellent bioactive functions and nutritional value. MFGM contains a diverse array of bioactive lipids, including cholesterol, phospholipids, and sphingolipids, which play pivotal roles in mediating the bioactivity of the MFGM. We sequentially summarize the main lipid types in the MFGM in this comprehensive review and outline the characterization methods used to employ them. In this comprehensive review, we sequentially describe the types of major lipids found in the MFGM and outline the characterization methods employed to study them. Additionally, we compare the structural disparities among glycerophospholipids, sphingolipids, and gangliosides, while introducing the formation of lipid rafts facilitated by cholesterol. The focus of this review revolves around an extensive evaluation of the current research on lipid isolates from the MFGM, as well as products containing MFGM lipids, with respect to their impact on human health. Notably, we emphasize the clinical trials encompassing a large number of participants. The summarized bioactive functions of MFGM lipids encompass the regulation of human growth and development, influence on intestinal health, inhibition of cholesterol absorption, enhancement of exercise capacity, and anticancer effects. By offering a comprehensive overview, the aim of this review is to provide valuable insights into the diverse biologically active functions exhibited by lipids in the MFGM.

Reassessing Stephanofilaria stilesi dermatitis in cattle, with characterization of molecular markers for confirming diagnosis

BackgroundStephanofilaria stilesi is a vector-borne filarioid nematode of cattle in North America that is transmitted via the hematophagous horn fly (Haematobia irritans) intermediate host. Despite being relatively common, little attention has been given to a thorough description of S. stilesi lesions and the potential integration of pathological and molecular diagnostic findings to confirm infection.MethodsTo characterize the cutaneous lesions caused by S. stilesi in cattle (Bos taurus taurus and Bos taurus indicus), skin of the ventral abdominal midline was collected from 22 animals during postmortem examination. Skin samples were processed for histology, transmission electron microscopy (TEM), DNA extraction, PCR, and Sanger sequencing targeting molecular markers cytochrome oxidase c subunit 1 (cox1), 12S, 18S rDNA, and 28S rDNA.ResultsMacroscopically, lesions ranged from 5 × 4 cm to 36 × 10 cm, consisting of one large single lesion, or two to four ovoid areas at the ventral abdominal midline, surrounding the umbilicus. Each lesion presented as ulcerative dermatitis with dry, serocellular crusts, or alopecic and lichenified areas. Histologically, eosinophilic, neutrophilic, and ulcerative dermatitis with furunculosis, folliculitis, and epidermal hyperplasia was observed. Cross sections of adult nematodes were identified in ~ 60% of the cases (n = 13) within intact follicles, sebaceous ducts, crusts, and areas of furunculosis. Stephanofilaria first-stage larvae (L1) were observed in five cases within “vitelline membranes” in the superficial dermis and crusts. Ultrastructurally, the L1 cross sections were compounded of smooth multilayered cuticle and somatic cells. The “vitelline membrane” is a tri-layered membrane where L1 are suspended in a matrix. Stephanofilaria stilesi DNA was found in 5 out of the 13 cases in which adults or L1 were histologically observed (38%) and in 1 out of the 9 cases without adults or L1 present (11%). Phylogenetic analyses suggest a closer relationship of the genus Stephanofilaria with Thelazioidea, instead of the family Filariidae (Filarioidea), in which it has been historically allocated.ConclusionsOur study improved the characterization of lesions and described ultrastructural findings of S. stilesi and highlights that molecular tools should be utilized in combination with histology for improved diagnostic resolution.Graphical

Study of Elastin, Hydrolyzed Collagen and Collagen-like Products in a Tri-Layered Chitosan Membrane to Test Anti-Aging Skin Properties.

The use of animal testing in the cosmetic industry is already prohibited in more than 40 countries, including those of the EU. The pressure for it to be banned worldwide in the future is increasing, so the need for animal alternatives is of great interest today. In addition, using animals and humans in scientific research is ethically reprehensible. This study aimed to prove some of the anti-aging properties of elastin (EL), hydrolyzed collagen (HC), and two vegan collagen-like products (Veg Col) in a tri-layered chitosan membrane that was ionically crosslinked with sodium tripolyphosphate (TPP). In the first approach, as a way of representing different layers of a biological system, such as the epidermis and the two dermis sublayers, EL, HC, or Veg Col were independently introduced into the two inner layers (2L(i+b)). Their effects were compared with those of their introduction into three layers (3L). Different experiments were performed on the membrane to test its elasticity, hydration, moisture retention, and pore reduction at different concentrations of EL, HC, and Veg Col, and the results were normalized vs. a blank membrane. This new alternative to animal or human testing can be suitable for proving certain efficacy claims for active ingredients or products in the pharmaceutical, nutritional, and cosmetic fields.

The effect of silver nanoparticle concentration on the antibacterial properties of tri-layer PCL-Ag/PT/PVP wound dressing

To comprehensively manage wound infection, tri-layer fibre membranes have been designed with two antibacterial agents, including silver nanoparticles (AgNPs) and chitosan oligosaccharide (COS), and their antibacterial properties were evaluated using qualitative and quantitative tests. While the first polycaprolactone (PCL) silver layer and the second plasma-treated PCL layer were fabricated by electrospinning, the third COS layer was constructed via coating and heat-vacuum drying. The formation of the membranes and their fibrous and porous structures were examined using scanning electron microscopy (SEM). The antibacterial activities of the membranes against Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus were examined by disk diffusion and percentage reduction assays, which were performed simultaneously as per the certificates from the Ministry of Health Institute of Public Health in Ho Chi Minh city. The tri-layer membranes, named PCLAg50/PT (plasma treatment)/COS and PCLAg500/PT/COS, achieved desirable antibacterial results with extensive inhibition zones and bacterial reduction rates ranging from 99-100%. In addition, while the PCLAg500 membrane exhibited broad inhibition zones and reduction rates ranging from 94.6-97%, the PCLAg50 membrane achieved reduction rates ranging from 67.5-82.1% despite the absence of inhibition zones. As a result, the fabricated tri-layer membranes could reduce local and opportunistic infections. Depending on infectious risks, the concentration of silver utilsed as an infection-prevention agent must be adjusted from 50 to 500 ppm to ensure safety.

Molecular dynamics simulation of hexagonal boron nitride slit membranes for wastewater treatment

Nanoporous boron nitride (BN) nanosheets are promising reverse-osmosis membrane materials, suitable for the removal of hazardous heavy metals, with advantages such as separation energy efficiency, eco-friendliness, heat resistance, acid resistance, and good antifouling properties. BN slit membranes (BNSMs) are a special class of nanoporous BN membranes that have not yet been extensively explored for heavy metal ion separation. To address the existing knowledge gap regarding these membranes, molecular dynamics (MD) simulations were performed herein to investigate the performance of BNSMs in purifying water from arsenic (As3+) and mercuric (Hg2+) cations, as well as chloride (Cl-) anions. For this purpose, the effects of slit width in monolayer, bilayer, and trilayer BN, interlayer distance, and membrane flexibility were evaluated. Based on the results obtained in this work, water flow rate increases, while ion rejection decreases, with increasing slit width. For rigid monolayer BNSMs having slit widths of 8–10 Å, the ion rejection percentage was in the order of As3+ > Cl- > Hg2+. The highest rejection percentage of As3+ cations in these membranes is attributed to their largest repulsive interaction energies of 27 kcal/mol with the membrane surface and the largest hydration radii of these cations (3.8 Å). For a rigid monolayer BNSM with the slit width of 7 Å, the rejection percentages of all ions were approximately equal to 100 % due to the dominant effect of slit geometric constraints against ion transport. For a rigid bilayer BNSM, both the number of filtered water molecules and water flow rate decreased with a decrease in the interlayer distance. In terms of ion rejection performance, the geometric constraints (size exclusion mechanism) were again responsible for the high (above 98 %) ion rejection percentages in these membranes with interlayer distances of 7–9 Å. Finally, flexible monolayer BNSMs were found to provide higher water flow rates and lower ion rejection percentages when compared to the rigid membranes. This behavior can be attributed to the larger slit cavity that results from membrane flexibility, thereby facilitating water flow and ion transport through the membrane. The use of molecular dynamics simulations in this study demonstrates the potential of computational methods in the design and screening of novel membrane materials, paving the way for further computational and experimental investigations in this field.

Changes in Milk Fat Globules and Membrane Proteins Prepared from pH-Adjusted Bovine Raw Milk.

Milk fat globules (MFGs) have tri-layer biological membrane structures, and their compositions are gaining more interest for their physiological benefits. In this study, the changes in MFGs and milk fat globule membrane (MFGM) proteins after cream separation from different pH bovine raw milk were investigated. Raw milk samples were adjusted to pH 5.30 and 6.30 using citric acid at 25 °C. The effect of pH and centrifugation on the structure of MFGs was evaluated by means of particle size, zeta potential and confocal laser scanning microscopy (CLSM). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to analyze the proteins in the obtained fractions. It was found that both pH and centrifugation could affect the particle size of all samples. As the volume distribution (Dv; Dv (10), Dv(50)and Dv (90)) decreased, the corresponding specific surface area (SSA) increased, and span and uniformity values showed the same trend. The decrease in the zeta potential of MFG correlated with the Dv(50), which was further confirmed by CLSM observation. More butyrophilin (BTN) and periodic acid Schiff 6/7 (PAS 6/7) were lost in cream samples at pH 5.30. The findings could provide valuable knowledge for the application of MFGs ingredient in the food industry since their structures and compositions could affect their potential functional and physiological properties.

Physico-mechanical and in-vivo evaluations of tri-layered alginate-gelatin/polycaprolactone-gelatin-β-TCP membranes for guided bone regeneration

Guided bone regeneration (GBR) membranes favor periodontal regrowth, but they still have certain limitations, such as improper biodegradation and poor mechanical property. To overcome these shortcomings, we have generated a unique multifunctional membrane. A polycaprolactone/gelatin/β-TCP and alginate/gelatin trilayered construction was fabricated through electrospinning and casting technology. The prepared membranes have suitable physicomechanical and in-vitro properties to confirm the compatibility of the product in the body. Phase analysis, functional groups, surface microstructure, and contact angle were measured as basic characteristics. For a mechanical performance evaluation, the tensile strength at suturing point was measured through pullout tensile strength test, and it showed the suture capability of bi-layered membranes. Highest tensile strength for A75G25 was recorded with 2.9 ± 0.15 MPa with 105% strain. Further, the osteoblast and fibroblast-type cell toxicity results showed that the electrospun membrane offered compatible environment to cells while the alginate sheet was found to be sufficiently capable to suppress the cellular attachment while also being a nontoxic material. Post-implantation, according to the in-vivo conclusions of the tri-layered membrane, there was appreciable bone formation. Compared to an implant without membrane covering, enhanced new bone formation can be identified after 8 weeks of implantation with P1G4β10 membranes-covered site.

Immobilized graphene oxide-based membranes for improved pore wetting resistance in membrane distillation

Membrane distillation (MD) is a useful method for the purification of difficult feedwaters but it cannot be applied in a range of industries due to pore wetting. In this work, graphene oxide (GO) laminate coatings are explored to overcome the pore wetting issues. Air gap MD (AGMD) configuration was considered, using a 35 g L−1 NaCl solution with 150 mg L−1 (150 ppm) of Triton X-100 surfactant as feed material. The GO is deposited as a laminate membrane on top of a commercial porous polyvinylidene fluoride (PVDF) support and good adhesion is achieved through the use of polydopamine (PDA) to form a hydrophilic tri-layer membrane. The small pore size achieved with the laminate GO led to increased pore wetting resistance for at least 90 h compared to 20 min with pristine commercial PVDF. Additionally, the extra layers of GO and PDA did not affect the membrane flux. Overall, a tri-layer immobilized GO membrane is synthesized with superior performance when compared to current commercial membranes, meaning that MD can be used for a new range of wastewater applications.

Milk Fat Globule Membrane Alleviates Short Bowel Syndrome-Associated Liver Injury in Rats Through Inhibiting Autophagy and NLRP3 Inflammasome Activation.

BackgroundThe milk fat globule membrane (MFGM), a tri-layer membrane structure surrounding the milk fat globule, has been shown to have immune-modulating properties. This study aimed to investigate the effects of MFGM supplementation in a rat model of short bowel syndrome (SBS) associated liver disease and its possible mechanisms.Materials and MethodsTwenty one male Sprague-Dawley rats were randomly divided into three groups: Sham, SBS (underwent massive small bowel resection), and SBS+MFGM (SBS rats supplemented with 1.5 g/kg/d MFGM). Liver pathology, myeloperoxidase (MPO) staining, serum levels of aspartate aminotransferase (AST)/alanine aminotransferase (ALT), endotoxin concentration, protein expression of autophagy and nucleotide binding oligomerization domain, leucine-rich repeat and pyrin domain-containing protein 3 (NLRP3) pathway in the liver tissue were measured.ResultsBoth SBS and SBS + MFGM groups had higher serum levels of ALT and liver endotoxin levels than the Sham group (P < 0.05), with no difference detected between each other. Compared with the SBS group, the SBS+MFGM group showed lower liver pathology scores of steatosis and inflammation, less MPO positive cells and reduced expressions of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), Caspase-1, interleukin (IL)-1β(P < 0.05) in the liver. Additionally, the expression of Beclin-1 and microtubule-associated protein1 light chain 3(LC3) B, the fluorescence intensity of NLRP3 and LC3B in the SBS + MFGM group were lower than the SBS group (P < 0.05). The LC3B expression was positively correlated with the NLRP3 level.ConclusionEnteral supplementation of MFGM help to alleviate liver injury in SBS rats, which might be related to inhibition of aberrant activation of autophagy and NLRP3 inflammasome pathways.

Temporal reverse osmotic salt filtration mechanism of multi-layered porous graphene

Reverse osmosis (RO) technology is currently the most progressive, energy-saving and efficient membrane separation technology . Meanwhile, graphene becomes a promising candidate for fabricating the RO membranes in water desalination due to its high salt rejection and water flux. The concept of “temporal selectivity” is first proposed in our previous work in terms of the time difference between the penetration time of an ion passing through the pore and the tangential slipping time for the ion sliding across the pore. Nevertheless, the temporal selectivity mechanism of multilayered graphene membrane remains ambiguous. In this paper, the RO process of saltwater through porous graphene column RO membrane is studied by using molecular dynamics (MD) simulations method, and the effects of rotating angular velocity and the thickness of RO membrane on desalination performance of seawater are considered first. The MD results show that the salt rejection increases with the rotation speed of porous membrane increasing while the water flux initially increases and then decreases . Meanwhile, the interfacial slip velocity increases linearly with angular velocity increasing. On the other hand, the increasing thickness of porous graphene membrane can enhance the selectivity and reduce the permeability of water molecules. As expected, the tri-layered porous graphene RO membrane can achieve high salt rejection at low interfacial slip velocity. In order to ensure high selectivity and energy conservation and efficient, the pore structure of the porous graphene RO membrane is optimized. The results show that the optimized nanopores can increase the water flux significantly, whereas the salt rejection is not changed appreciably. It is found that the pore size of the innermost layer membrane near the feed region has the most significant effect on the water flux. The water flux increases sharply with the increase of pore diameter and the salt rejection remains totally higher than 80%. Moreover, the RO membrane with a special Type 3 structure exhibits excellent performance in seawater desalination, specifically, the ultrahigh water flux reaches 20029 L·cm&lt;sup&gt;–2&lt;/sup&gt;·d&lt;sup&gt;–1&lt;/sup&gt; and the super salt rejection arrives at 94%. The research results further clarify and verify the mechanism of the temporal selectivity in RO process, and improve the water flux under the condition of the same membrane thickness by designing gradient hole. The findings can conduce to the in-depth theoretical understanding of porous graphene-based membranes and designing and developing the large-scale seawater desalination devices and water filtration equipment.