Composite Membranes Research Articles

Identification of genes associated with sperm storage capacity in hens at different times after insemination by RNA-seq and Ribo-seq

BackgroundSperm storage capacity (SSC) determines the duration of fertility in hens and is an important reproduction trait that cannot be ignored in production. Currently, the genetic mechanism of SSC is still unclear in hens. Therefore, to explore the genetic basis of SSC, we analyzed the uterus-vagina junction (UVJ) of hens with different SSC at different times after insemination by RNA-seq and Ribo-seq.ResultsOur results showed that 589, 596, and 527 differentially expressed genes (DEGs), 730, 783, and 324 differentially translated genes (DTGs), and 804, 625, and 467 differential translation efficiency genes (DTEGs) were detected on the 5th, 10th, and 15th days after insemination, respectively. In transcription levels, we found that the differences of SSC at different times after insemination were mainly reflected in the transmission of information between cells, the composition of intercellular adhesion complexes, the regulation of ion channels, the regulation of cellular physiological activities, the composition of cells, and the composition of cell membranes. In translation efficiency (TE) levels, the differences of SSC were mainly related to the physiological and metabolic activities in the cell, the composition of the organelle membrane, the physiological activities of oxidation, cell components, and cell growth processes. According to pathway analysis, SSC was related to neuroactive ligand-receptor interaction, histidine metabolism, and PPAR signaling pathway at the transcriptional level and glutathione metabolism, oxidative phosphorylation, calcium signaling pathway, cell adhesion molecules, galactose metabolism, and Wnt signaling pathway at the TE level. We screened candidate genes affecting SSC at transcriptional levels (COL4A4, MUC6, MCHR2, TACR1, AVPR1A, COL1A1, HK2, RB1, VIPR2, HMGCS2) and TE levels(COL4A4, MUC6, CYCS, NDUFA13, CYTB, RRM2, CAMK4, HRH2, LCT, GCK, GALT). Among them, COL4A4 and MUC6 were the key candidate genes differing in transcription, translation, and translation efficiency.ConclusionsOur study used the combined analysis of RNA-seq and Ribo-seq for the first time to investigate the SSC and reveal the physiological processes associated with SSC. The key candidate genes affecting SSC were screened, and the theoretical basis was provided for the analysis of the molecular regulation mechanism of SSC.

Stimulated Full-Thickness Cutaneous Wound Healing with Bioactive Dressings of Zinc and Cobalt Ion-Doped Bioactive Glass-Coated Eggshell Membranes in a Diabetic Rabbit Model.

Eggshell membrane-based biomedical applications have recently received great attention for their wound-healing properties. However, there are limited studies on diabetic wound healing. In this regard, we devised four types of composite eggshell membrane mats with nanoscale coatings of bioactive glass/Zn/Co-doped bioactive glass (ESM + BAG, ESM + ZnBAG, ESM + CoBAG, and ESM + ZnCoBAG) as wound-dressing materials for chronic nonhealing diabetic wounds. A detailed study of the physicochemical properties of the mats was conducted. In vitro studies demonstrated cytocompatibility and viability of human dermal fibroblasts on all four types of mats. The cells also attached finely on the mats with the help of cellular extensions, as evident from scanning electron microscopy (SEM) and rhodamine-phalloidin and Hoechst 33342 staining of cellular components. Endowed with bioactive properties, these mats influenced all aspects of full-thickness skin wound healing in diabetic animal model studies. All of the mats, especially the ESM + ZnCoBAG mat, showed the earliest wound closure, effective renewal, and restructuring of the extracellular matrix in terms of an accurate and timely accumulation of collagen, elastin, and reticulin fibers. Hydroxyproline and sulfated glycosaminoglycans were significantly (p < 0.01, p < 0.05) higher in ESM-ZnCoBAG-treated wounds in comparison to ESM-BAG-treated wounds, which suggests that these newly developed mats have potential as an affordable diabetic wound care solution in biomedical research.

Synthesis of clay/Fe/ZSM-5 composite membrane for chromium (vi) removal from aqueous media and its electrochemical performance

The present study explores the potential use of a Clay/Fe/ZSM-5 zeolite membrane as an effective platform for Chromium (VI) filtration. The raw clay sourced from Wadi Haqil Ras Al-Khaimah-UAE was utilized for fabricating the clay support sintered at 1000°C. Clay powder with a granulometry range of 125 µm ≤ Φ ≤ 250 µm, was obtained through crushing and sieving with ASTM sieves and used to prepare the clay support. The Fe/ZSM-5 zeolite was synthesized via the hydrothermal method, using tetrapropylammonium bromide (TPABr) as an organic structure-directing template. The characterization of both the clay support sintered at 1000°C and Fe/ZSM-5 zeolite membrane was conducted through various techniques, including XRD, FTIR, FE-SEM coupled with EDS, and XPS analysis. Notably, the support exhibited a relatively high deionized water flux, stabilizing at 140 L.m−2.h−1 after 120 min of operation, indicating excellent permeability. FE-SEM observations confirmed that Fe/ZSM-5 consisted primarily of granular particles with an orthorhombic crystal lattice, aligning with its crystallinity demonstrated by XRD analysis. The filtration tests for Cr(VI) solutions, conducted using a flow loop designed for cross-flow filtration, demonstrated retention rates of 23 % and 40 % for the clay support and Fe/ZSM-5 zeolite membrane, respectively, after a working time of 120 min. These results suggest the potential of Fe/ZSM-5 zeolite as an effective alternative adsorbent for removing Cr(VI) from wastewater, showcasing outstanding performance in this application. The Clay support and Fe/ZSM-5 zeolite membrane materials were used as electrodes for cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in [Fe(CN)6]3-/4-/0.1 M KCl solution, and Fe/ZSM-5 zeolite membrane material exhibited high electrochemical charge transfer compared to the clay support material.

Acidic sphingomyelinase interactions with lysosomal membranes and cation amphiphilic drugs: A molecular dynamics investigation

Lysosomes are pivotal in cellular functions and disease, influencing cancer progression and therapy resistance with Acid Sphingomyelinase (ASM) governing their membrane integrity. Moreover, cation amphiphilic drugs (CADs) are known as ASM inhibitors and have anti-cancer activity, but the structural mechanisms of their interactions with the lysosomal membrane and ASM are poorly explored. Our study, leveraging all-atom explicit solvent molecular dynamics simulations, delves into the interaction of glycosylated ASM with the lysosomal membrane and the effects of CAD representatives, i.e., ebastine, hydroxyebastine and loratadine, on the membrane and ASM. Our results confirm the ASM association to the membrane through the saposin domain, previously only shown with coarse-grained models. Furthermore, we elucidated the role of specific residues and ASM-induced membrane curvature in lipid recruitment and orientation. CADs also interfere with the association of ASM with the membrane at the level of a loop in the catalytic domain engaging in membrane interactions. Our computational approach, applicable to various CADs or membrane compositions, provides insights into ASM and CAD interaction with the membrane, offering a valuable tool for future studies.

Mass transport mechanism of nitrate selective nanofiltration membranes on the basis of the Donnan steric pore model with dielectric exclusion (DSPM-DE)

Nanofiltration (NF) membranes can play an important role to mitigate the nitrate pollution, emphasizing the necessity for understanding its mass transport mechanism to enhance water purification strategies. This study focuses on the nitrate separation capabilities of thin film composite NF membranes having a polyamide (PA) selective layer. The selective layer of the membranes was fabricated through interfacial polymerization, with varying piperazine (PIP) and trimesoyl chloride (TMC) monomer concentrations on porous polyacrylonitrile substrates. We studied their retention on aqueous solutions of PEG 200, single salts (NaCl, NaNO3, Na2SO4), and mixed salts (NaCl + NaNO3 and NaNO3 + Na2SO4). Through a new fitting scheme, the Donnan Steric Pore Model with Dielectric Exclusion (DSPM-DE) was utilized to correlate the PIP and TMC concentrations with the ion transport and exclusion mechanisms responsible for the membranes’ nitrate separation capabilities. The model could simulate the Na+/NO3-/SO42- system but not Na+/NO3-/Cl-. Dielectric exclusion and diffusion were the dominant partitioning and transport mechanisms, respectively, explaining the high retentions of sulfate (96 to 99 %) and the negative retentions of nitrate (−24 to 11 %). This study sheds light on the potential of NF membranes having PA selective layers for efficient nitrate/sulfate separation, providing valuable insights into the underlying transport and exclusion mechanisms.

Metal-organic framework integrated surface-engineered polyelectrolyte membranes enhancing tetrahydrofuran dehydration

BackgroundEnhancing composite membrane performance is crucial for industrial separation processes. Integrating metal-organic frameworks (MOFs) into membranes offers a promising strategy. We introduce a novel approach by integrating HKUST-1 MOF within a polyelectrolyte matrix to improve membrane efficiency. MethodsA layer-by-layer self-assembly technique on a hydrolyzed polyacrylonitrile support integrates HKUST-1 into a polyelectrolyte matrix. Polyethyleneimine (PEI) and polyacrylic acid (PAA) form the polyelectrolyte layer through electrostatic interactions. The incorporation of HKUST-1 within the PEI matrix enhances separation efficiency, particularly in tetrahydrofuran dehydration, with optimal conditions using 100 ppm of HKUST-1 and forming 2 bilayers. Significant findingsUnder optimal conditions, the resulting membrane exhibits exceptional performance. It demonstrates a permeation flux of 1442.30 g∙m−2∙h−1, a water concentration in the permeate of 98.0 wt%, and a separation factor of 440. The modified membrane also shows remarkable stability across varying temperatures (25–55 °C) and tetrahydrofuran concentrations in the feed (10–90 wt%) during long-term testing. These findings highlight the membrane's potential for enhancing separation processes in the chemical industry.

Optimized poly(methyl methacrylate)/mixed‐phase silver vanadate nanocomposites with tuned optical properties and hydrophobicity

AbstractThe fast advancements in technology have generated significant interest in optoelectronic materials. Nevertheless, the difficulty of creating affordable materials with exceptional optical characteristics is an ongoing challenge. Therefore, the objective of this work was to tune the optical properties of poly(methyl methacrylate) (PMMA) by embedding silver vanadate (SV) in the polymer matrix. Moreover, the wettability test of the fabricated composite membranes showed a hydrophobic behavior, with the PMMA film containing 0.6 wt.% SV showed a contact angle of 86.75 ± 0.7°. Furthermore, SV showed high thermal stability with a maximum weight loss of 0.74% at 830°C, which is very high thermal stability at high temperatures. In addition, the 0.6 wt.% SV@PMMA film exhibited a maximum weight loss of 96.7% at 785°C. Moreover, the 0.6 wt.% SV@PMMA film showed the lowest indirect band gap energy (2.02 eV) compared to the other films and pure SV NPs. The findings demonstrate the potential of the synthesized films for optoelectronic applications.

Laminated graphene oxide and hydrotalcite membranes via alternating spray-deposition with stable desalting performance

Laminated graphene oxide (GO) membrane has great potential for desalination, but achieving good stability in salt retention and water permeation is still a challenge. The “compact” sieving structure and the “loose” permeating structure of the GO membranes offer synergetic effects for high-performance desalination. Here, a composite desalination membrane involving two two-dimensional layered nanomaterials with opposite charges has been reported. The multi-layered GO (MLGO) and hydrotalcite (HT) were then alternated in a spray-coating on a PDA-modified substrate to construct multiple structures. Different assembly regions were identified by in-situ morphology monitoring, which showed that MLGO and HT were connected by electrostatic attractions. Also, the composite membrane showed high salt retention, permeability and long-term performance stability. The water flux of the composite membrane increased from 2.8 L m−2 h−1 bar−1 to 3.6–5.2 L m−2 h−1, which was due to the increases in the interlayer spacing distances and the introduction of new permeable spaces. After a 400 h continuous filtration test, the Na2SO4 retention remained stable. The water fluxes were in the range of 2.0–3.0 L m−2 h−1 bar−1, which corresponded to an increase by 42.9 %–114.3 % in comparison with the pure MLGO membrane. As compared with the MLGO membrane, molecular dynamics (MD) simulations revealed that more water molecules passed through the MLGO-HT membrane with a shorter pathway length and higher speed than MLGO membrane. The present study demonstrated the potential of a composite with 2D materials for desalination applications.

Asymmetric multilayered cellulose nanofiber composite membranes with electrical-magnetic dual-gradient architectures towards excellent electromagnetic interference shielding performance

Asymmetric multilayered cellulose nanofiber composite membranes with electrical-magnetic dual-gradient architectures towards excellent electromagnetic interference shielding performance

Facile preparation and catalytic property of a sandwich composite membrane

Membrane as a support for metal nanocatalysts, can greatly enhance the catalytic activity of metal nanoparticles and promote the efficient production and separation of products. In this study, a novel sandwich-structured composite membrane was designed and facilely fabricated by using palladium nanocatalysts as the core catalytic layer and two different structured PVDF layers as the outer layers. The composite membrane was used as a reaction interface as well as a separation barrier between reactants and products, efficiently realizing the catalytic oxidation of benzyl alcohol and convenient separation of the product benzaldehyde. The membrane was characterized in detailed and the effects of the membrane structure and various reaction conditions on the catalytic oxidation were systematically investigated. The results indicated that the reaction could be conveniently carried out under very mild experimental conditions, obtaining the product benzaldehyde at as high selectivity as 93.17 %. The successful implementation of the sandwich membrane for the production of chlorine-free benzaldehyde provides a new method for the interface reaction.

Polyvinyl alcohol-encapsulated cerium oxide nanospheres composite nanofiber membrane for enhanced antioxidant and antibacterial applications☆

Cerium oxide (CeO2) has attracted much attention in recent years owing to its reversible switch ability in Ce3+/Ce4+ redox to produce improved antioxidation properties for biomedical applications. Here, we report to embed the CeO2 nanospheres into the organic polymer network using electrostatic spinning technology to prepare polyvinyl alcohol (PVA)-encapsulated CeO2 nanospheres composite nanofibrous membranes (PVA-CeO2) for the first time, which is beneficial to improving the dispersion and biocompatibility of CeO2 nanosphere without altering the original antioxidant properties of CeO2. Detailed characterization of the as-prepared composite nanofibrous membranes reveals that CeO2 was successfully introduced into the PVA fibers with strong interactions, thus enhancing the thermal stability and fracture toughness of the nanofibers. As a result, PVA-CeO2 exhibits superior UV shielding performance, antioxidant performance and bacteriostatic performance. Meaningfully, PVA-CeO2 has strong absorbance in both UVA and UVB bands when the CeO2 concentration in the nanofiber membrane reaches 1.5 wt%, and shows an excellent scavenging effect on the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals with a scavenging rate of 86.52%. Moreover, the Kirby-Bauer (K-B) method of agar diffusion test further confirms that PVA-CeO2 has antimicrobial ability against three types of representative strains, including Gram-positive bacteria (Staphylococcus aureus), Gram-negative bacteria (Escherichia coli) and fungi (Candida albicans). Importantly, no obvious cytotoxicity is observed for PVA-CeO2 even though the amount of embedded CeO2 nanosphere reaches as high as 1.5 wt%. This study reveals new avenues for improving the future smart design of CeO2-based nanofiber membrane composite materials for biological antioxidants.

Eco-Friendly Superhydrophobic Modification of Low-Cost Multi-Layer Composite Mullite Base Tubular Ceramic Membrane for Water Desalination

This study aimed to investigate and develop a cost-effective and superhydrophobic ceramic membrane for direct contact membrane distillation (DCMD) applications. Two types of mullite-based composite membranes were prepared via extrusion and sintering techniques. To create a small and narrow pore diameter distribution on the membrane surface, the dip-coating technique with 1 µm alumina was employed. The hexadecyltrimethoxysilane eco-friendly grafting agent was adopted to modify low-cost multilayer mullite-based composite membranes, transforming them from hydrophilic to superhydrophobic. The prepared membranes were characterized via field emission scanning electron microscopy (FESEM), energy-dispersive spectrometry (EDS), Fourier Transform Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), liquid entire pressure (LEP), contact angle, atomic force microscopy (AFM), porosity, and membrane permeability. The results of the prepared membranes validate the appropriateness of the material for membrane distillation applications. The optimized membrane, with a contact angle of 160° and LEP = 1.5 bar, was tested under DCMD using a 3.5 wt.% sodium chloride (NaCl) synthetic solution and Persian Gulf seawater as a feed. Based on the acquired results, an average permeate flux of 3.15 kg/(m2·h) and salt rejection (R%) of 99.62% were found for the 3.5 wt.% NaCl solution. Moreover, seawater desalination showed an average permeate flux of 2.37 kg/(m2·h) and salt rejection of 99.81% for a 20-h test without any pore wetting. Membrane distillation with a hydrophobic membrane decreased the turbidity of seawater by 93.13%.

Preparation of PVDF-nSiO2/PVSQ high-flux composite membrane by chemical grafting and separation of composite brine by membrane distillation

The large-scale application of membrane distillation (MD), an important method for desalting seawater, is limited due to membrane fouling. In this study, ethyl orthosilicate (TEOS) was polymerized to obtain different nSiO2 particles. Vinyl triethoxysilane (VTES) was hydrolysed and polycondensation was used to produce spherical polyethylene-sesquioxane (PVSQ) microparticles, which were modified to construct micro/nano particles. Then grafted on the surface of polyvinylidene fluoride (PVDF) composite membrane. The low-surface-energy hydrophobic groups present on the surfaces of the vinyl and ethoxy particles greatly enhanced the membrane hydrophobicity. The particle size of nSiO2 can change the properties of the membrane. The separation performance of the membrane was tested by direct contact membrane distillation (DCMD). In the separation of a constant concentration of feed solution (3.5wt% NaCl), the membrane flux was relatively stable at 23.8kg·m−2·h−1, and the salt interception rate reached 99.99%. In the subsequent separation of a salt/humic acid solution, the flux remained stable and the good anti-fouling performance indicating that this system outperformed the unmodified membrane. Finally, the effect of different cations on the water diffusivity was studied using a molecular simulation method. Both Ca2+ and Mg2+ reduced the diffusion coefficient of water. However, when these two ions were present simultaneously, Ca2+ inhibited the binding of Mg2+ to water, and the diffusion coefficient of water increased. This study provides a novel approach for preparing hydrophobic membranes for the separation of complex brines.

A one-stone-two-birds strategy for cellulose dissolution, regeneration, and functionalization as a photocatalytic composite membrane for wastewater purification

Photocatalytic membranes integrate membrane separation and photocatalysis to deliver an efficient solution for water purification, while the top priority is to exploit simple, efficient, renewable, and low-cost photocatalytic membrane materials. We herein propose a facile one-stone-two-birds strategy to construct a multifunctional regenerated cellulose composite membrane decorated by Prussian blue analogue (ZnPBA) microspheres for wastewater purification. The hypotheses are that: 1) ZnCl2 not only serves as a cellulose solvent for tuning cellulose dissolution and regeneration, but also functions as a precursor for in-situ growth of spherical-like ZnPBA; 2) More homogeneous reactions including coordination and hydrogen bonding among Zn2+, [Fe(CN)6]3− and cellulose chains contribute to a rapid and uniform anchoring of ZnPBA microspheres on the regenerated cellulose fibrils (RCFs). Consequently, the resultant ZnPBA/RCM features a high loading of ZnPBA (65.3 wt%) and exhibits excellent treatment efficiency and reusability in terms of photocatalytic degradation of tetracycline (TC) (90.3 % removal efficiency and 54.3 % of mineralization), oil-water separation efficiency (>97.8 % for varying oils) and antibacterial performance (99.4 % for E. coli and 99.2 % for S. aureus). This work paves a simple and useful way for exploiting cellulose-based functional materials for efficient wastewater purification.

Mussel-inspired polydopamine and Zr-porphyrin MOF co-decoration of a cellulose paper-based composite membrane for efficient photoreduction of Cr(VI) and photothermal antibacterial in wastewater

Abundant hazardous pollutants, in particular heavy metal ions and microbes, in aqueous systems seriously threaten ecological safety and human health. Photocatalysis is deemed an appealing solution yet remains challenging to exploit more efficient, economical, and sustainable photocatalytic materials. In this study, we successfully fabricated a cellulose paper-based composite membrane, namely Zr-TCPP@PDA@FP, for photoreduction of Cr(VI) and photothermal antimicrobial. For the resultant composite membrane, the self-polymerization polydopamine (PDA)-coated cellulose fibers act as sustainable scaffolds to anchor the in-situ synthesized porphyrin-doped UiO-66-NH2 (Zr-TCPP) nano-photocatalysts. The hypotheses are that: 1) porphyrin doping in Zr-TCPP can both reinforce the visible-light absorption and the transport of photogenerated electrons; 2) mussel-inspired PDA coating on fiber surface not only services as binder to promote the Zr-TCPP loading and dispersion, but also functions as heterojunction interface to accelerate photogenerated electron separation and transfer from Zr-TCPP; As a result, Zr-TCPP@PDA@FP exhibited significant photocatalytic reduction towards Cr(VI), achieving a removal efficiency of 93.9 % within 20 mins and cycling stability. Besides, the hybrid membrane also featured excellent photothermal antibacterial performance (over 99 % for both E. coli and S. aureus). This work will inspire the development of economic and sustainable cellulose-based functional materials for efficient wastewater remediation.

Polymerization-induced self-assembly amino acid ionic liquid/poly(ethylene oxide) thin-film composite membranes for CO2 separation

It is well known that crosslinking poly(ethylene oxide) (PEO) membranes exhibit high CO2/N2 solubility selectivity, and are suitable for separating CO2 from flue gas. However, the high CO2/N2 selectivity is temperature sensitive and decreases rapidly with increasing temperature. To overcome this deficiency, imidazolium-based amino acid ionic liquids (AAILs) are introduced into the PEO membranes. A series of (AAILs-PEO)/PAN thin-film composite (TFC) membranes were prepared by a polymerization-induced self-assembly process. Due to the hydrogen and Coulomb interactions between the imidazolium ring of AAILs and the ether groups of PEO monomers, the morphology of the selective layer changed from micellar to granular upon the introduction of the AAILs into the PEO membranes, while the chain-segment flexibility and interspacing of the PEO are also changed. Compared with the original PEO/PAN TFC membrane, the (AAILs-PEO)/PAN TFC membranes show much higher CO2/N2 selectivity, which increases from ∼41 to ∼ 74. In addition, the AAILs show strong hydrophilicity, which leads to a significant increase in CO2/N2 selectivity under the wet-gas feed, reaching ∼105. Compared with the original PEO/PAN TFC membranes with CO2/N2 selectivity of ∼10 at 70 °C, the (AAILs-PEO)/PAN TFC membranes show the selectivity of ∼30, coupled with CO2 permeance of ∼1300 GPU at 70 °C. Under the 40: 60 mixtures of CO2: N2, which is a common lime kiln exhaust gas, by using the (AAILs-PEO)/PAN TFC membrane, the CO2 concentration on the downstream side can reach over 90 % at 20 °C and over 70 % at 70 °C, respectively, under a pressure ratio of 5.

Deciphering the mechanisms involved in reduced sensitivity to azoles and fengycin lipopeptide in Venturia inaequalis

Apple scab, caused by the hemibiotrophic fungus Venturia inaequalis, is currently the most common and damaging disease in apple orchards. Two strains of V. inaequalis (S755 and Rs552) with different sensitivities to azole fungicides and the bacterial metabolite fengycin were compared to determine the mechanisms responsible for these differences. Antifungal activity tests showed that Rs552 had reduced sensitivity to tebuconazole and tetraconazole, as well as to fengycin alone or in a binary mixture with other lipopeptides (iturin A, pumilacidin, lichenysin). S755 was highly sensitive to fengycin, whose activity was close to that of tebuconazole. Unlike fengycin, lipopeptides from the iturin family (mycosubtilin, iturin A) had similar activity on both strains, while those from the surfactin family (lichenysin, pumilacidin) were not active, except in binary mixtures with fengycin. The activity of lipopeptides varies according to their family and structure. Analyses to determine the difference in sensitivity to azoles (which target the CYP51 enzyme involved in the ergosterol biosynthesis pathway) showed that the reduced sensitivity in Rs552 is linked to (i) a constitutive increased expression of the Cyp51A gene caused by insertions in the upstream region and (ii) greater efflux by membrane pumps with the involvement of ABC transporters. Microscopic observations revealed that fengycin, known to interact with plasma membranes, induced morphological and cytological changes in cells from both strains. Sterol and phospholipid analyses showed a higher level of ergosta-7,22-dien-3-ol and a lower level of PI(C16:0/C18:1) in Rs552 compared with S755. These differences could therefore influence the composition of the plasma membrane and explain the differential sensitivity of the strains to fengycin. However, the similar antifungal activities of mycosubtilin and iturin A in the two strains indirectly indicate that sterols are probably not involved in the fengycin resistance mechanism. This leads to the conclusion that different mechanisms are responsible for the difference in susceptibility to azoles or fengycin in the strains studied.

Potential of electrospun fibrous membranes involving tri-n-octylphosphine oxide for selective clearance of uremic toxin p-cresol over urea and creatinine

In this study, various electrospun and electrosprayed fibrous membranes from polyethersulfone (PES) and polyvinylpyrrolidone (PVP) were fabricated, to which a common solvating extractant tri-n-octylphosphine oxide (TOPO) was incorporated. Such TOPO-involved PES membranes were attempted to selectively clear p-cresol, one of trace amounts of small uremic toxins, from simulated serum via hydrogen bonding. Morphological and physicochemical properties of the as-synthesized fibrous membranes were first studied. Batch tests displayed that the equilibrium of p-cresol adsorption on all fibrous membranes were attained within 2 h. Analysis of adsorption isotherms of p-cresol by the Langmuir equation revealed that the adsorption was improved in the presence of TOPO; moreover, the distribution state of TOPO powders along the fibers played an important role in membrane performance. Among the six as-prepared TOPO-incorporated membranes, the highest adsorption capacity of p-cresol in simulated serum at 37oC and pH 7.4 reached to be 21.7 mmol per gram of TOPO. The operational stability of as-prepared fibrous membranes was evaluated by checking their adsorption ability, membrane weight, water contact angle, structural changes by SEM imaging, and PVP dissolution using UV–Vis spectroscopy, both before and after exposure to PBS solution. Crossflow permeation-adsorption of a multicomponent mixture (0.46 mmol/L of p-cresol, 1.33 mmol/L of creatinine, and 38.3 mmol/L of urea) for 4 h indicated that the prepared membranes yielded a high selectivity toward p-cresol against creatinine and urea of 21.2–43.0 and 10.8–18.5, respectively. Hemolysis tests and viability measurements of both human umbilical vein endothelial cells and THP 1 monocytic leukemia cells demonstrated that the proposed configurations of the TOPO-incorporated fibrous membranes were hemo- and bio-compatible. Our results on the composition and systematic design of these fibrous membranes suggested that they can serve as an advanced hemoperfusion unit, maintaining high p-cresol removal and bio-compatibility. These well-designed membrane-based devices could be connected in series with the conventional hemodialysis devices to further improve the overall removal of small uremic toxins.

Preparation and Characterization of Novel Multifunctional Wound Dressing by Near-Field Direct-Writing Electrospinning and Its Application.

Near-field direct-writing electrospinning technology can be used to produce ordered micro/nanofiber membrane dressings. The application of this technology can simply realize the control of dressing porosity, compound different functional substances, and adjust their distribution, thus improving the defects of common dressings such as insufficient breathability, poor moisture retention performance, and single function. Herein, a novel multifunctional wound dressing was prepared to utilize near-field direct-writing electrospinning technology, in which calf skin collagen type I (CSC-I) and polycaprolactone (PCL) were used as the composite matrix, Hexafluoroisopropanol (HFIP) as the solvent, and erythromycin (ERY) as an anti-infective drug component. The results show that the micro/nanofiber membranes prepared by near-field direct-writing electrospinning technology can all present a complete mesh structure, excellent thermal stability, and good moisturizing properties. Moreover, the composite fiber membrane loaded with ERY not only had obvious antibacterial properties against E. coli and S. thermophilus but also a better slow-release function of drugs (it is rare to have both in traditional wound dressings). Therefore, this experimental design can provide relevant theories and an experimental foundation for preparing a new type of medical dressing with drug loading and has good guiding significance for the application and promotion of near-field direct-writing electrospinning in medical dressings.

Influence of polar solvent in formation and organic solvent separation performance of novel fluorine-containing polyamide membranes

Polyamide thin film composite (PA-TFC) membranes have shown great potential in organic solvent separations. However, the intrinsic polar feature of the amide group limits their permeability to specific solvents, such as nonpolar solvents. In this study, we used a fluorine-containing monomer [4,4′-oxybis(3-(trifluoromethyl)aniline), OTFA] to conduct interfacial polymerization (IP) with trimesoyl chloride, resulting in the fabrication of novel PA-TFC membranes with permeability to both polar and nonpolar solvents. Interestingly, by simply adjusting the composition of OTFA solvents [DMF and DMF/water (1:1, v: v)], we obtained two PA-TFC membranes (OTFA-D and OTFA-DH, respectively) featuring completely different structures and surface properties, including PA layer thickness, water contact angle, surface element composition, surface charge, and polarity. Due to their distinct structures and surface features, the two membranes exhibited different performances in organic solvent nanofiltration (OSN). The OTFA-DH membrane showed higher permeability to polar solvents (e.g., methanol), while the OTFA-D membrane was more permeable to nonpolar solvents (e.g., toluene). The mechanism on the formation of the two PA layers was clarified by combining the experimental results with the molecular dynamics simulations. The significantly different interfacial properties and monomer diffusion during IP led to the substantial differences in the formation of the PA network. This work provides a strategy to fabricate tailored PA-TFC membranes for various OSN scenarios by simply adjusting the solvent compositions.