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Membranes, Volume 11, Issue 11 (November 2021) – 110 articles

Cover Story (view full-size image): Ammonia emissions from intensive livestock farming are a source of public concern. Their reduction through the application of best available techniques alone may be insufficient to meet environmental goals, which makes technologies that simultaneously reduce NH3 emissions and allow N recovery particularly important. In this work, an NH3-capture prototype, based on the use of expanded polytetrafluoroethylene gas-permeable membranes, was tested in real conditions in a gestating sow house and a free-range laying hen house. Differences were observed between seasons and farms. Given that the limiting factor for the capture process was the NH3 concentration in the air, with the highest recovery occurring in the most concentrated atmosphere, possible scenarios for the application of this emerging technology are proposed. View this paper
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23 pages, 15292 KiB  
Review
Current Status and Future Trend of Dominant Commercial Reverse Osmosis Membranes
by Masaru Kurihara
Membranes 2021, 11(11), 906; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110906 - 22 Nov 2021
Cited by 14 | Viewed by 3636
Abstract
Since 2000, seawater reverse osmosis method has been a dominant desalination technology against the distillation method in the global market. The large project called “Mega-SWRO” (half mega-ton per day and larger) plant in the Middle East is quite popular making full use of [...] Read more.
Since 2000, seawater reverse osmosis method has been a dominant desalination technology against the distillation method in the global market. The large project called “Mega-SWRO” (half mega-ton per day and larger) plant in the Middle East is quite popular making full use of the combination with solar energy. Today, the price of desalinated water is affordable at as low as $0.28/m3 to $0.53/m3. Likewise, dominant commercial reverse osmosis membrane is a cross-linked fully aromatic polyamide composite membrane-spiral wound element including FT-30 (DuPont Water Solution) and UTC-80 (Toray Industries., Inc., Otsu, Shiga, Japan). The said membranes are much superior in terms of performance compared to the cellulose triacetate membranes-hollow fiber for variety of applications including seawater desalinations, brackish water desalination, wastewater reuse, ultra-pure production for semiconductor, home-use water purifier, etc. SWCC of Saudi Arabia has announced that it intends to shift from cellulose triacetate hollow fiber to spiral wound RO membranes at all of its plants. Furthermore, the state-sponsored R&D on membrane and membrane process has been put into practice in major countries, including Japan and Korea, which contributed to the progress of membrane science and membrane process, suitable for spiral-wound polyamide membranes. SWCC has announced their plans for SWRO, mainly focusing on brine mining to obtain precious materials from the brine of SWRO. New and innovative brine-mining technology has been introduced for green desalination. Full article
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13 pages, 4962 KiB  
Article
Liposome Sterile Filtration Characterization via X-ray Computed Tomography and Confocal Microscopy
by Thomas F. Johnson, Kyle Jones, Francesco Iacoviello, Stephen Turner, Nigel B. Jackson, Kalliopi Zourna, John H. Welsh, Paul R. Shearing, Mike Hoare and Daniel G. Bracewell
Membranes 2021, 11(11), 905; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110905 - 22 Nov 2021
Cited by 1 | Viewed by 2235
Abstract
Two high resolution, 3D imaging techniques were applied to visualize and characterize sterilizing grade dual-layer filtration of liposomes, enabling membrane structure to be related with function and performance. Two polyethersulfone membranes with nominal retention ratings of 650 nm and 200 nm were used [...] Read more.
Two high resolution, 3D imaging techniques were applied to visualize and characterize sterilizing grade dual-layer filtration of liposomes, enabling membrane structure to be related with function and performance. Two polyethersulfone membranes with nominal retention ratings of 650 nm and 200 nm were used to filter liposomes of an average diameter of 143 nm and a polydispersity index of 0.1. Operating conditions including differential pressure were evaluated. X-ray computed tomography at a pixel size of 63 nm was capable of resolving the internal geometry of each membrane. The respective asymmetry and symmetry of the upstream and downstream membranes could be measured, with pore network modeling used to identify pore sizes as a function of distance through the imaged volume. Reconstructed 3D digital datasets were the basis of tortuous flow simulation through each porous structure. Confocal microscopy visualized liposome retention within each membrane using fluorescent dyes, with bacterial challenges also performed. It was found that increasing pressure drop from 0.07 MPa to 0.21 MPa resulted in differing fluorescent retention profiles in the upstream membrane. These results highlighted the capability for complementary imaging approaches to deepen understanding of liposome sterilizing grade filtration. Full article
(This article belongs to the Special Issue Bioprocessing with Membranes: Filtration and Chromatography)
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15 pages, 2076 KiB  
Article
Mitigating Silica Fouling and Improving PPCP Removal by Modified NF90 Using In Situ Radical Graft Polymerization
by Yi-Li Lin, Nai-Yun Zheng, Hao-Yu Gan, An-Xian Chang, Huai-Xuan Luo and Yao-Jie Mao
Membranes 2021, 11(11), 904; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110904 - 22 Nov 2021
Cited by 2 | Viewed by 1711
Abstract
This study in-situ modified a commercial nanofiltration membrane, NF90, through the concentration-polymerization-enhanced radical graft polarization method by applying two agents of 3-sulfopropyl methacrylate potassium salt (SPM) and 2-hydroxyethyl methacrylate (HEMA) with different dosages. Surface characterization revealed that the modified membranes became rougher and [...] Read more.
This study in-situ modified a commercial nanofiltration membrane, NF90, through the concentration-polymerization-enhanced radical graft polarization method by applying two agents of 3-sulfopropyl methacrylate potassium salt (SPM) and 2-hydroxyethyl methacrylate (HEMA) with different dosages. Surface characterization revealed that the modified membranes became rougher and more hydrophilic compared with the pristine membrane. The modified membranes exhibited considerably enhanced separation performance with 5.8–19.6% higher NaCl rejection and 17.2–19.9% higher pharmaceuticals and personal care products (PPCPs) rejection than the pristine membrane. When treating the feedwater with high silica concentration, the modified membranes exhibited relatively less flux decline with high percentage of reversible fouling, especially the ones modified using a lower monomer concentration (0.01 M SPM and 0.01 M HEMA). Moreover, membrane modification enhanced the PPCP rejection (1.3–5.4%) after silica fouling by mitigating foulant deposition on the membrane surface. The fouling mechanism was confirmed to be intermediate blocking of membrane pores. Therefore, the in-situ modification technique with a low monomer concentration proved to be effective for mitigating silica fouling and improving PPCP rejection, which can be easily performed and cost-effective in practical application. Full article
(This article belongs to the Special Issue Membrane Fouling Control in Water Treatment)
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12 pages, 2305 KiB  
Article
Incorporation of Au Nanoparticles on ZnO/ZnS Core Shell Nanostructures for UV Light/Hydrogen Gas Dual Sensing Enhancement
by Yu-Sheng Tsai, Deng-Yi Wang, Jia-Jie Chang, Keng-Tien Liang, Ya-Hsuan Lin, Chih-Chen Kuo, Ssu-Han Lu, Yewchung Sermon Wu, Lukas Jyuhn-Hsiarn Lee, Hsiang Chen and Dong-Sing Wuu
Membranes 2021, 11(11), 903; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110903 - 22 Nov 2021
Cited by 3 | Viewed by 1876
Abstract
ZnO/ZnS nanocomposite-based nanostructures exhibit dual light and gas sensing capabilities. To further boost the light/dual sensing properties, gold nanoparticles (Au NPs) were incorporated into the core-shell structures. Multiple material characterizations revealed that Au NPs were successfully well spread and decorated on ZnO/ZnS nanostructures. [...] Read more.
ZnO/ZnS nanocomposite-based nanostructures exhibit dual light and gas sensing capabilities. To further boost the light/dual sensing properties, gold nanoparticles (Au NPs) were incorporated into the core-shell structures. Multiple material characterizations revealed that Au NPs were successfully well spread and decorated on ZnO/ZnS nanostructures. Furthermore, our findings show that the addition of Au NPs could enhance both 365 nm UV light sensing and hydrogen gas sensing in terms of light/gas sensitivity and light/gas response time. We postulate that the optimization of gas/light dual sensing capability may result from the induced electric field and inhabitation of electron-hole recombination. Owing to their compact size, simple fabrication, and stable response, ZnO/ZnS/Au NPs-based light/gas dual sensors are promising for future extreme environmental monitoring. Full article
(This article belongs to the Section Membrane Applications)
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8 pages, 2297 KiB  
Article
Steep Subthreshold Swing and Enhanced Illumination Stability InGaZnO Thin-Film Transistor by Plasma Oxidation on Silicon Nitride Gate Dielectric
by Yiming Liu, Chang Liu, Houyun Qin, Chong Peng, Mingxin Lu, Zhanguo Chen and Yi Zhao
Membranes 2021, 11(11), 902; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110902 - 22 Nov 2021
Cited by 4 | Viewed by 1869
Abstract
In this paper, an InGaZnO thin-film transistor (TFT) based on plasma oxidation of silicon nitride (SiNx) gate dielectric with small subthreshold swing (SS) and enhanced stability under negative bias illumination stress (NBIS) have been investigated in detail. The mechanism of the [...] Read more.
In this paper, an InGaZnO thin-film transistor (TFT) based on plasma oxidation of silicon nitride (SiNx) gate dielectric with small subthreshold swing (SS) and enhanced stability under negative bias illumination stress (NBIS) have been investigated in detail. The mechanism of the high-performance InGaZnO TFT with plasma-oxidized SiNx gate dielectric was also explored. The X-ray photoelectron spectroscopy (XPS) results confirmed that an oxygen-rich layer formed on the surface of the SiNx layer and the amount of oxygen vacancy near the interface between SiNx and InGaZnO layer was suppressed via pre-implanted oxygen on SiNx gate dielectric before deposition of the InGaZnO channel layer. Moreover, the conductance method was employed to directly extract the density of the interface trap (Dit) in InGaZnO TFT to verify the reduction in oxygen vacancy after plasma oxidation. The proposed InGaZnO TFT with plasma oxidation exhibited a field-effect mobility of 16.46 cm2/V·s, threshold voltage (Vth) of −0.10 V, Ion/Ioff over 108, SS of 97 mV/decade, and Vth shift of −0.37 V after NBIS. The plasma oxidation on SiNx gate dielectric provides a novel approach for suppressing the interface trap for high-performance InGaZnO TFT. Full article
(This article belongs to the Special Issue Thin-Film Transistors)
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16 pages, 3767 KiB  
Article
Anion Exchange Membranes Based on Imidazoline Quaternized Polystyrene Copolymers for Fuel Cell Applications
by Li-Cheng Jheng, Chung-Yen Hsu and Hong-Yi Yeh
Membranes 2021, 11(11), 901; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110901 - 22 Nov 2021
Cited by 7 | Viewed by 2446
Abstract
Imidazoline is a five-membered heterocycle derived by the partial reduction of one double bond of the imidazole ring. This work prepared new anion exchange membranes (AEMs) based on imidazoline quaternized polystyrene copolymers bearing N-b-hydroxyethyl oleyl imidazolinium pendent groups to evaluate the application potential [...] Read more.
Imidazoline is a five-membered heterocycle derived by the partial reduction of one double bond of the imidazole ring. This work prepared new anion exchange membranes (AEMs) based on imidazoline quaternized polystyrene copolymers bearing N-b-hydroxyethyl oleyl imidazolinium pendent groups to evaluate the application potential for anion exchange membrane fuel cells (AEMFCs). For comparison, an imidazole quaternized polystyrene copolymer was also synthesized. The polymer chemical structure was confirmed by FTIR, NMR, and TGA. In addition, the essential properties of membranes, including ion exchange capacity (IEC), water uptake, and hydroxide conductivity, were measured. The alkaline stabilities of imidazolium-based and imidazolinium-based AEMs were compared by means of the changes in the TGA thermograms, FTIR spectra, and hydroxide conductivity during the alkaline treatment in 1 M KOH at 60 °C for 144 h. The results showed that the imidazolinium-based AEMs exhibited relatively lower hydroxide conductivity (5.77 mS/cm at 70 °C) but much better alkaline stability compared with the imidazolium-based AEM. The imidazolinium-based AEM (PSVBImn-50) retained 92% of its hydroxide conductivity after the alkaline treatment. Besides, the fuel cell performance of the imidazolium-based and imidazolinium-based AEMs was examined by single-cell tests. Full article
(This article belongs to the Special Issue Membranes in Electrochemistry Applications)
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14 pages, 2064 KiB  
Article
Recovery of Biologically Treated Textile Wastewater by Ozonation and Subsequent Bipolar Membrane Electrodialysis Process
by Burak Yuzer and Huseyin Selcuk
Membranes 2021, 11(11), 900; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110900 - 21 Nov 2021
Cited by 14 | Viewed by 2134
Abstract
The Bipolar Membrane Electrodialysis process (BPMED) can produce valuable chemicals such as acid (HCl, H2SO4, etc.) and base (NaOH) from saline and brackish waters under the influence of an electrical field. In this study, BPMED was used to recover [...] Read more.
The Bipolar Membrane Electrodialysis process (BPMED) can produce valuable chemicals such as acid (HCl, H2SO4, etc.) and base (NaOH) from saline and brackish waters under the influence of an electrical field. In this study, BPMED was used to recover wastewater and salt in biologically treated textile wastewater (BTTWW). BPMED process, with and without pre-treatment (softening and ozonation), was evaluated under different operational conditions. Water quality parameters (color, remaining total organic carbon, hardness, etc.) in the acid, base and filtrated effluents of the BPMED process were evaluated for acid, base, and wastewater reuse purposes. Ozone oxidation decreased 90% of color and 37% of chemical oxygen demand (COD) in BTTWW. As a result, dye fouling on the anion exchange membrane of the BPMED process was reduced. Subsequently, over 90% desalination efficiency was achieved in a shorter period. Generated acid, base, and effluent wastewater of the BPMED process were found to be reusable in wet textile processes. Results indicated that pre-ozonation and subsequent BPMED membrane systems might be a promising solution in converging to a zero discharge approach in the textile industry. Full article
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11 pages, 2779 KiB  
Article
A Novel Nitrogen Ion Implantation Technique for Turning Thin Film “Normally On” AlGaN/GaN Transistor into “Normally Off” Using TCAD Simulation
by Gene Sheu, Yu-Lin Song, Dupati Susmitha, Kutagulla Issac and Ramyasri Mogarala
Membranes 2021, 11(11), 899; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110899 - 20 Nov 2021
Cited by 2 | Viewed by 3357
Abstract
This study presents an innovative, low-cost, mass-manufacturable ion implantation technique for converting thin film normally on AlGaN/GaN devices into normally off ones. Through TCAD (Technology Computer-Aided Design) simulations, we converted a calibrated normally on transistor into a normally off AlGaN/GaN transistor grown on [...] Read more.
This study presents an innovative, low-cost, mass-manufacturable ion implantation technique for converting thin film normally on AlGaN/GaN devices into normally off ones. Through TCAD (Technology Computer-Aided Design) simulations, we converted a calibrated normally on transistor into a normally off AlGaN/GaN transistor grown on a silicon <111> substrate using a nitrogen ion implantation energy of 300 keV, which shifted the bandgap from below to above the Fermi level. In addition, the threshold voltage (Vth) was adjusted by altering the nitrogen ion implantation dose. The normally off AlGaN/GaN device exhibited a breakdown voltage of 127.4 V at room temperature because of impact ionization, which showed a positive temperature coefficient of 3 × 10−3 K−1. In this study, the normally off AlGaN/GaN device exhibited an average drain current gain of 45.3%, which was confirmed through an analysis of transfer characteristics by changing the gate-to-source ramping. Accordingly, the proposed technique enabled the successful simulation of a 100-µm-wide device that can generate a saturation drain current of 1.4 A/mm at a gate-to-source voltage of 4 V, with a mobility of 1487 cm2V−1s−1. The advantages of the proposed technique are summarized herein in terms of processing and performance. Full article
(This article belongs to the Special Issue Thin-Film Transistors)
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16 pages, 2103 KiB  
Article
Highly Stable Potentiometric (Bio)Sensor for Urea and Urease Activity Determination
by Marcin Urbanowicz, Kamila Sadowska, Agnieszka Paziewska-Nowak, Anna Sołdatowska and Dorota G. Pijanowska
Membranes 2021, 11(11), 898; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110898 - 20 Nov 2021
Cited by 5 | Viewed by 2848
Abstract
There is growing interest for bioanalytical tools that might be designed for a specific user, primarily for research purposes. In this perspective, a new, highly stable potentiometric sensor based on glassy carbon/polyazulene/NH4+-selective membrane was developed and utilized for urease activity [...] Read more.
There is growing interest for bioanalytical tools that might be designed for a specific user, primarily for research purposes. In this perspective, a new, highly stable potentiometric sensor based on glassy carbon/polyazulene/NH4+-selective membrane was developed and utilized for urease activity determination. Urease–urea interaction studies were carried out and the Michaelis–Menten constant was established for this enzymatic reaction. Biofunctionalization of the ammonium ion-selective sensor with urease lead to urea biosensor with remarkably good potential stability (drift coefficient ~0.9 mV/h) and short response time (t95% = 36 s). The prepared biosensor showed the Nernstian response (S = 52.4 ± 0.7 mV/dec) in the urea concentration range from 0.01 to 20 mM, stable for the experimental time of 60 days. In addition, some insights into electrical properties of the ion-to-electron transducing layer resulting from impedance spectroscopy measurements are presented. Based on the RCQ equivalent circuits comparison, it can be drawn that the polyazulene (PAz) layer shows the least capacitive behavior, which might result in good time stability of the sensor in respect to response as well as potential E0. Both the polyazulene-based solid-contact ion selective electrodes and urea biosensors were successfully used in trial studies for determination of ammonium ion and urea in human saliva samples. The accuracy of ammonium ion and urea levels determination by potentiometric method was confirmed by two reference spectrophotometric methods. Full article
(This article belongs to the Special Issue Ion-Selective Separation Membrane)
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12 pages, 1909 KiB  
Article
The Ionic Selectivity of Lysenin Channels in Open and Sub-Conducting States
by Andrew Bogard, Pangaea W. Finn, Fulton McKinney, Ilinca M. Flacau, Aviana R. Smith, Rosey Whiting and Daniel Fologea
Membranes 2021, 11(11), 897; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110897 - 19 Nov 2021
Cited by 4 | Viewed by 2025
Abstract
The electrochemical gradients established across cell membranes are paramount for the execution of biological functions. Besides ion channels, other transporters, such as exogenous pore-forming toxins, may present ionic selectivity upon reconstitution in natural and artificial lipid membranes and contribute to the electrochemical gradients. [...] Read more.
The electrochemical gradients established across cell membranes are paramount for the execution of biological functions. Besides ion channels, other transporters, such as exogenous pore-forming toxins, may present ionic selectivity upon reconstitution in natural and artificial lipid membranes and contribute to the electrochemical gradients. In this context, we utilized electrophysiology approaches to assess the ionic selectivity of the pore-forming toxin lysenin reconstituted in planar bilayer lipid membranes. The membrane voltages were determined from the reversal potentials recorded upon channel exposure to asymmetrical ionic conditions, and the permeability ratios were calculated from the fit with the Goldman–Hodgkin–Katz equation. Our work shows that lysenin channels are ion-selective and the determined permeability coefficients are cation and anion-species dependent. We also exploited the unique property of lysenin channels to transition to a stable sub-conducting state upon exposure to calcium ions and assessed their subsequent change in ionic selectivity. The observed loss of selectivity was implemented in an electrical model describing the dependency of reversal potentials on calcium concentration. In conclusion, our work demonstrates that this pore-forming toxin presents ionic selectivity but this is adjusted by the particular conduction state of the channels. Full article
(This article belongs to the Collection Feature Papers in Membranes in Life Sciences)
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14 pages, 5007 KiB  
Article
A Single Step Preparation of Photothermally Active Polyvinylidene Fluoride Membranes Using Triethyl Phosphate as a Green Solvent for Distillation Applications
by Marcello Pagliero, Antonio Comite, Camilla Costa, Ilaria Rizzardi and Omar Soda
Membranes 2021, 11(11), 896; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110896 - 19 Nov 2021
Cited by 8 | Viewed by 2127
Abstract
Membrane distillation is a growing technology that can address the growing problem of water shortage. The implementation of renewable energy and a reduction in the environmental impact of membrane production could improve the sustainability of this process. With this perspective, porous hydrophobic polyvinylidene [...] Read more.
Membrane distillation is a growing technology that can address the growing problem of water shortage. The implementation of renewable energy and a reduction in the environmental impact of membrane production could improve the sustainability of this process. With this perspective, porous hydrophobic polyvinylidene fluoride (PVDF) membranes were prepared using triethyl phosphate (TEP) as a green solvent, using the non-solvent induced phase separation technique. Different amounts of carbon black were added to dope solutions to improve the photothermal properties of the membranes and to enable direct heating by solar energy. By optimizing the preparation conditions, membranes with porosity values as high as 87% were manufactured. Vacuum membrane distillation tests carried out using a concentrated NaCl solution at 50 °C showed distillate fluxes of up to 36 L/m2 h and a complete salt rejection. Some preliminary studies on the photothermal performance were also conducted and highlighted the possibility of using such membranes in a direct solar membrane distillation configuration. Full article
(This article belongs to the Special Issue State-of-the-Art Membrane Science and Technology in Italy 2021, 2022)
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15 pages, 6311 KiB  
Article
Interfacial Modulation of Graphene by Polythiophene with Controlled Molecular Weight to Enhance Thermal Conductivity
by Ya Li, Yu Wang, Peng Chen, Ru Xia, Bin Wu and Jiasheng Qian
Membranes 2021, 11(11), 895; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110895 - 19 Nov 2021
Cited by 3 | Viewed by 1850
Abstract
With a trend of continuing improvement in the development of electronic devices, a problem of serious heat accumulation has emerged which has created the need for more efficient thermal management. Graphene sheets (GNS) have drawn much attention with regard to heat transfer because [...] Read more.
With a trend of continuing improvement in the development of electronic devices, a problem of serious heat accumulation has emerged which has created the need for more efficient thermal management. Graphene sheets (GNS) have drawn much attention with regard to heat transfer because of their excellent in-plane thermal conductivity; however, the ultrahigh interfacial thermal resistance between graphene lamellae has seriously restricted its practical applications. Herein, we describe heat transfer membranes composed of graphene which have been modified by intrinsic thermally conductive polymers with different molecular weights. The presence of macromolecular surface modifiers not only constructed the graphene heat transfer interface by π–π interactions, but also significantly enhanced the membranes’ in-plane thermal conductivity by utilizing their intrinsic heat transfer properties. Such results indicated that the in-plane thermal conductivity of the fabricated membrane exhibits a high in-plane thermal conductivity of 4.17 W m−1 K−1, which, containing the GNS modified with 6000 g/mol (Mn) of poly(3-hexylthiophene) (P3HT), was 26 times higher that of poly (vinylidene fluoride) (PVDF). The P3HT molecular chain with specific molecular weight can form more matching structure π–π interactions, which promotes thermal conductivity. The investigation of different molecular weights has provided a new pathway for designing effective interfacial structures to relieve interface thermal resistance in thermally conductive membranes. Full article
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12 pages, 3006 KiB  
Article
The Pilot Study of the Influence of Free Ammonia on Membrane Fouling during the Partial Nitrosation of Pig Farm Anaerobic Digestion Liquid
by Hanxiao Bian, Zhiping Zhu, Qianwen Sui and Shunli Wang
Membranes 2021, 11(11), 894; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110894 - 19 Nov 2021
Viewed by 1540
Abstract
The problem of membrane fouling is a key factor restricting the application of the membrane bioreactor (MBR) in the partial nitrosation (PN) and anaerobic ammonia oxidation (anammox) processes. In this study, the pilot-scale continuous flow MBR was used to start up the partial [...] Read more.
The problem of membrane fouling is a key factor restricting the application of the membrane bioreactor (MBR) in the partial nitrosation (PN) and anaerobic ammonia oxidation (anammox) processes. In this study, the pilot-scale continuous flow MBR was used to start up the partial nitrosation process in order to investigate the change trend of mid-transmembrane pressure (TMP) in the process of start-up, which was further explored to clarify the membrane fouling mechanism in the pilot-scale reactor. The results showed that the MBR system was in a stable operating condition during the partial nitrosation operation and that the online automatic backwash operation mode is beneficial in alleviating membrane fouling and reducing the cost of membrane washing. Particular attention was paid to the influence trend of free ammonia (FA)on membrane fouling, and it was found that the increase in FA concentration plays the most critical role in membrane fouling. The increase in FA concentration led to an increase in the extracellular polymer (EPS), dissolved microorganism product (SMP) and soluble chemical oxygen demand (SCOD) concentration. FA was extremely significantly correlated with EPS and SCOD, and the FA concentration was approximately 20.7 mg/L. The SCODeff (effluent SCOD concentration) concentration was approximately 147 mg/L higher than the SCODinf (influent SCOD concentration) concentration. FA mainly affects membrane fouling by affecting the concentration of EPS and SCOD. Full article
(This article belongs to the Special Issue Bioprocessing with Membranes: Filtration and Chromatography)
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12 pages, 25188 KiB  
Article
Phosphodiesterase Type 5 Inhibitors Greatly Affect Physicochemical Properties of Model Lipid Membranes
by Anastasiia A. Zakharova, Svetlana S. Efimova and Olga S. Ostroumova
Membranes 2021, 11(11), 893; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110893 - 19 Nov 2021
Cited by 2 | Viewed by 1517
Abstract
Although phosphodiesterase type 5 inhibitors are widely used and well-studied drugs, the potential benefits of their application in the treatment of various diseases and new drug delivery systems, including liposome forms, are still being discussed. In this regard, the role of the lipid [...] Read more.
Although phosphodiesterase type 5 inhibitors are widely used and well-studied drugs, the potential benefits of their application in the treatment of various diseases and new drug delivery systems, including liposome forms, are still being discussed. In this regard, the role of the lipid matrix of cell membranes in the pharmacological action of the inhibitors is of special interest. It was shown that sildenafil, vardenafil, and tadalafil caused a significant decrease in the boundary potential of model membranes composed of palmitoyloleoylphosphatidylcholine or its mixture with cholesterol, by 70–80 mV. The reduction in the membrane dipole potential induced by inhibitors led to a 20–25% increase in the conductance of cation-selective pores formed by the antimicrobial peptide gramicidin A. The addition of sildenafil or vardenafil also led to a significant decrease in the temperature of the main phase transition of dipalmytoylphosphatidylcholine, by about 1.5 °C, while tadalafil did not change the melting temperature. Sildenafil, vardenafil, and tadalafil enhanced the pore-forming activity of the antifungal polyene antibiotic nystatin by 11, 13, and 2 times, respectively. This fact might indicate the induction of membrane curvature stress by the inhibitors. The data obtained might be of special interest for the development of lipid-mediated forms of drugs. Full article
(This article belongs to the Special Issue Electrostatics in Cell Membranes and in Artificial Membrane Models)
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15 pages, 880 KiB  
Article
Reduction of Cost and Environmental Impact in the Treatment of Textile Wastewater Using a Combined MBBR-MBR System
by Xuefei Yang and Víctor López-Grimau
Membranes 2021, 11(11), 892; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110892 - 19 Nov 2021
Cited by 6 | Viewed by 2747
Abstract
A hybrid Moving Bed Biofilm Reactor—Membrane Bioreactor (MBBR-MBR) was developed for the treatment of wastewater from a Spanish textile company. Compared with conventional activated sludge (CAS) treatment, the feasibility of this hybrid system to reduce economic and environmental impact on an industrial scale [...] Read more.
A hybrid Moving Bed Biofilm Reactor—Membrane Bioreactor (MBBR-MBR) was developed for the treatment of wastewater from a Spanish textile company. Compared with conventional activated sludge (CAS) treatment, the feasibility of this hybrid system to reduce economic and environmental impact on an industrial scale was conducted. The results showed that, technically, the removal efficiency of COD, TSS and color reached 93%, 99% and 85%, respectively. The newly dyed fabrics performed with the treated wastewater were qualified under the standards of the textile industry. Economically, the values of Capital Expenditure (CAPEX) calculated for the hybrid MBBR-MBR system are profitable because of the reduction in Operational Expenditure (OPEX) when compared with CAS treatment, due to the lower effluent discharge tax thanks to the higher quality of the effluent and the decolorizing agent saved. The result of Net Present Value (NPV) and the Internal Rate of Return (IRR) of 18% suggested that MBBR-MBR is financially applicable for implantation into the industrial scale. The MBBR-MBR treatment also showed lower environmental impacts than the CAS process in the life cycle assessment (LCA) study, especially in the category of climate change, thanks to the avoidance of using extra decolorizing agent, a synthetic product based on a triamine. Full article
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14 pages, 2447 KiB  
Article
Nanodrug Transmembrane Transport Research Based on Fluorescence Correlation Spectroscopy
by Xinwei Gao, Yanfeng Liu, Jia Zhang, Luwei Wang, Yong Guo, Yinru Zhu, Zhigang Yang, Wei Yan and Junle Qu
Membranes 2021, 11(11), 891; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110891 - 19 Nov 2021
Cited by 1 | Viewed by 1666
Abstract
Although conventional fluorescence intensity imaging can be used to qualitatively study the drug toxicity of nanodrug carrier systems at the single-cell level, it has limitations for studying nanodrug transport across membranes. Fluorescence correlation spectroscopy (FCS) can provide quantitative information on nanodrug concentration and [...] Read more.
Although conventional fluorescence intensity imaging can be used to qualitatively study the drug toxicity of nanodrug carrier systems at the single-cell level, it has limitations for studying nanodrug transport across membranes. Fluorescence correlation spectroscopy (FCS) can provide quantitative information on nanodrug concentration and diffusion in a small area of the cell membrane; thus, it is an ideal tool for studying drug transport across the membrane. In this paper, the FCS method was used to measure the diffusion coefficients and concentrations of carbon dots (CDs), doxorubicin (DOX) and CDs-DOX composites in living cells (COS7 and U2OS) for the first time. The drug concentration and diffusion coefficient in living cells determined by FCS measurements indicated that the CDs-DOX composite distinctively improved the transmembrane efficiency and rate of drug molecules, in accordance with the conclusions drawn from the fluorescence imaging results. Furthermore, the effects of pH values and ATP concentrations on drug transport across the membrane were also studied. Compared with free DOX under acidic conditions, the CDs-DOX complex has higher cellular uptake and better transmembrane efficacy in U2OS cells. Additionally, high concentrations of ATP will cause negative changes in cell membrane permeability, which will hinder the transmembrane transport of CDs and DOX and delay the rapid diffusion of CDs-DOX. The results of this study show that the FCS method can be utilized as a powerful tool for studying the expansion and transport of nanodrugs in living cells, and might provide a new drug exploitation strategy for cancer treatment in vivo. Full article
(This article belongs to the Collection Feature Papers in Membranes in Life Sciences)
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34 pages, 3444 KiB  
Review
Advances and Applications of Hollow Fiber Nanofiltration Membranes: A Review
by Tim Sewerin, Maria G. Elshof, Sonia Matencio, Marcel Boerrigter, Jimmy Yu and Joris de Grooth
Membranes 2021, 11(11), 890; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110890 - 19 Nov 2021
Cited by 22 | Viewed by 7878
Abstract
Hollow fiber nanofiltration (NF) membranes have gained increased attention in recent years, partly driven by the availability of alternatives to polyamide-based dense separation layers. Moreover, the global market for NF has been growing steadily in recent years and is expected to grow even [...] Read more.
Hollow fiber nanofiltration (NF) membranes have gained increased attention in recent years, partly driven by the availability of alternatives to polyamide-based dense separation layers. Moreover, the global market for NF has been growing steadily in recent years and is expected to grow even faster. Compared to the traditional spiral-wound configuration, the hollow fiber geometry provides advantages such as low fouling tendencies and effective hydraulic cleaning possibilities. The alternatives to polyamide layers are typically chemically more stable and thus allow operation and cleaning at more extreme conditions. Therefore, these new NF membranes are of interest for use in a variety of applications. In this review, we provide an overview of the applications and emerging opportunities for these membranes. Next to municipal wastewater and drinking water processes, we have put special focus on industrial applications where hollow fiber NF membranes are employed under more strenuous conditions or used to recover specific resources or solutes. Full article
(This article belongs to the Special Issue New Phenomenological Findings in Nanofiltration)
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17 pages, 53365 KiB  
Article
Organo-Functionalization: An Effective Method in Enhancing the Separation and Antifouling Performance of Thin-Film Nanocomposite Membranes by Improving the Uniform Dispersion of Palygorskite Nanoparticles
by Liu Yang, Qianwen Zhang, Qikun Wang, Wande Ding and Kefeng Zhang
Membranes 2021, 11(11), 889; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110889 - 19 Nov 2021
Cited by 5 | Viewed by 1584
Abstract
Recently, palygorskite (Pal) has become a promising new membrane additive in flux enhancement and fouling reduction, which is an environmentally friendly nanoclay material under the 2:1 layer composition with 1D tubular structure. However, the aggregation of Pal due to the intermolecular forces is [...] Read more.
Recently, palygorskite (Pal) has become a promising new membrane additive in flux enhancement and fouling reduction, which is an environmentally friendly nanoclay material under the 2:1 layer composition with 1D tubular structure. However, the aggregation of Pal due to the intermolecular forces is still an obstacle to be solved in improving membrane performance. Herein, Pal nanoparticles were chemically modified by KH550 to weaken the aggregation and improve the dispersibility, and then incorporated into the organic phase to prepare thin-film nanocomposite (TFN) membranes. The results showed that the organo-functionalization could effectively improve the membrane hydrophilicity and dispersion of Pal nanoparticles in the polyamide layer, which contributed to the enhanced water flux (from 25 to 38 L/m2·h), unchanged salt rejection (98.0%) and better antifouling capacity (91% flux recovery rate), which suggested that the organo-functionalization of nanoparticles was an efficient method in further enhancing membrane performance Full article
(This article belongs to the Special Issue Mixed-Matrix Membranes and Polymeric Membranes)
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23 pages, 1249 KiB  
Review
State-of-the-Art Ceramic Membranes for Oily Wastewater Treatment: Modification and Application
by Mingliang Chen, Sebastiaan G. J. Heijman and Luuk C. Rietveld
Membranes 2021, 11(11), 888; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110888 - 19 Nov 2021
Cited by 24 | Viewed by 5340
Abstract
Membrane filtration is considered to be one of the most promising methods for oily wastewater treatment. Because of their hydrophilic surface, ceramic membranes show less fouling compared with their polymeric counterparts. Membrane fouling, however, is an inevitable phenomenon in the filtration process, leading [...] Read more.
Membrane filtration is considered to be one of the most promising methods for oily wastewater treatment. Because of their hydrophilic surface, ceramic membranes show less fouling compared with their polymeric counterparts. Membrane fouling, however, is an inevitable phenomenon in the filtration process, leading to higher energy consumption and a shorter lifetime of the membrane. It is therefore important to improve the fouling resistance of the ceramic membranes in oily wastewater treatment. In this review, we first focus on the various methods used for ceramic membrane modification, aiming for application in oily wastewater. Then, the performance of the modified ceramic membranes is discussed and compared. We found that, besides the traditional sol-gel and dip-coating methods, atomic layer deposition is promising for ceramic membrane modification in terms of the control of layer thickness, and pore size tuning. Enhanced surface hydrophilicity and surface charge are two of the most used strategies to improve the performance of ceramic membranes for oily wastewater treatment. Nano-sized metal oxides such as TiO2, ZrO2 and Fe2O3 and graphene oxide are considered to be the potential candidates for ceramic membrane modification for flux enhancement and fouling alleviation. The passive antifouling ceramic membranes, e.g., photocatalytic and electrified ceramic membranes, have shown some potential in fouling control, oil rejection and flux enhancement, but have their limitations. Full article
(This article belongs to the Special Issue Membrane Filtration for Water Reclamation)
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20 pages, 2811 KiB  
Article
The Use of NaOH Solutions for Fouling Control in a Membrane Bioreactor: A Feasibility Study
by Wirginia Tomczak, Ireneusz Grubecki and Marek Gryta
Membranes 2021, 11(11), 887; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110887 - 18 Nov 2021
Cited by 8 | Viewed by 2236
Abstract
Nowadays, the microbial production of 1,3-propanediol (1,3-PD) is recognized as preferable to the chemical synthesis. However, finding a technological approach allowing the production of 1,3-PD in the membrane bioreactor (MBR) is a great challenge. In the present study, a ceramic ultrafiltration (UF) membrane [...] Read more.
Nowadays, the microbial production of 1,3-propanediol (1,3-PD) is recognized as preferable to the chemical synthesis. However, finding a technological approach allowing the production of 1,3-PD in the membrane bioreactor (MBR) is a great challenge. In the present study, a ceramic ultrafiltration (UF) membrane (8 kDa) for treatment of 1,3-PD broths was used. It has been demonstrated that the membrane used provides the stable permeate flux that is necessary to ensure the stability of the fermentation process in MBR technology. It was noticed that the broth pH has a significant impact on both the final 1,3-PD concentration and permeate flux. Moreover, the feasibility of using NaOH for fouling control in the MBR was evaluated. It has been shown that 1% NaOH solution is effective in restoring the initial membrane performance. To the best of our knowledge, this study is the first to shed light onto the possibility of reducing the amount of the alkaline solutions generated during the MBR operation. Indeed, it has been found that 1% NaOH solution can be successfully used several times for both membrane cleaning and to stabilize the broth pH. Finally, based on the results obtained, the technological conceptions of the MBR technology were designed. Full article
(This article belongs to the Special Issue Bioprocessing with Membranes: Filtration and Chromatography)
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18 pages, 3383 KiB  
Article
Extracellular Vesicles Tropism: A Comparative Study between Passive Innate Tropism and the Active Engineered Targeting Capability of Lymphocyte-Derived EVs
by Tania Limongi, Francesca Susa, Bianca Dumontel, Luisa Racca, Michela Perrone Donnorso, Doriana Debellis and Valentina Cauda
Membranes 2021, 11(11), 886; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110886 - 18 Nov 2021
Cited by 13 | Viewed by 3637
Abstract
Cellular communications take place thanks to a well-connected network of chemical–physical signals, biomolecules, growth factors, and vesicular messengers that travel inside or between cells. A deep knowledge of the extracellular vesicle (EV) system allows for a better understanding of the whole series of [...] Read more.
Cellular communications take place thanks to a well-connected network of chemical–physical signals, biomolecules, growth factors, and vesicular messengers that travel inside or between cells. A deep knowledge of the extracellular vesicle (EV) system allows for a better understanding of the whole series of phenomena responsible for cell proliferation and death. To this purpose, here, a thorough immuno-phenotypic characterization of B-cell EV membranes is presented. Furthermore, the cellular membrane of B lymphocytes, Burkitt lymphoma, and human myeloid leukemic cells were characterized through cytofluorimetry assays and fluorescent microscopy analysis. Through cytotoxicity and internalization tests, the tropism of B lymphocyte-derived EVs was investigated toward the parental cell line and two different cancer cell lines. In this study, an innate capability of passive targeting of the native EVs was distinguished from the active targeting capability of monoclonal antibody-engineered EVs, able to selectively drive the vesicles, enhancing their internalization into the target cancer cells. In particular, the specific targeting ability of anti-CD20 engineered EVs towards Daudi cells, highly expressing CD20 marker on their cell membrane, was proved, while almost no internalization events were observed in HL60 cells, since they did not express an appreciable amount of the CD20 marker on their plasma membranes. Full article
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9 pages, 1727 KiB  
Article
Self-Propelled Motion Sensitive to the Chemical Structure of Amphiphilic Molecular Layer on an Aqueous Phase
by Muneyuki Matsuo, Hiromi Hashishita and Satoshi Nakata
Membranes 2021, 11(11), 885; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110885 - 17 Nov 2021
Cited by 3 | Viewed by 1548
Abstract
Two novel amphiphiles, N-(3-nitrophenyl)stearamide (MANA) and N,N′-(4-nitro-1,3-phenylene)distearamide (OPANA), were synthesized by reacting nitroanilines with one or two equivalents of stearic acid. We investigated how the molecular structures of these compounds influenced the characteristics of a self-propelled camphor disk placed [...] Read more.
Two novel amphiphiles, N-(3-nitrophenyl)stearamide (MANA) and N,N′-(4-nitro-1,3-phenylene)distearamide (OPANA), were synthesized by reacting nitroanilines with one or two equivalents of stearic acid. We investigated how the molecular structures of these compounds influenced the characteristics of a self-propelled camphor disk placed on a monolayer of the synthesized amphiphiles. Three types of motion were observed at different surface pressures (Π): continuous motion (Π < 4 mN m−1), deceleration (4 mN ≤ Π ≤ 20 mN m−1), and no motion (Π > 20 mN m−1). The speed of the motion of the camphor disks was inversely related to Π for both MANA and OPANA at the temperatures tested, when Π increased in the respective molecular layers under compression. The spectroscopic evidence from UV-Vis, NMR, and ESI-TOF-MS revealed that the dependence of the speed of the motion on Π originates from the intermolecular interactions that are present in the monolayers. This study suggests that it is possible to control the self-propelled motion by manipulating contributing factors at the molecular level. Full article
(This article belongs to the Section Membrane Surfaces and Interfaces)
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29 pages, 4489 KiB  
Review
Effective Parameters on Fabrication and Modification of Braid Hollow Fiber Membranes: A Review
by Azadeh Nazif, Hamed Karkhanechi, Ehsan Saljoughi, Seyed Mahmoud Mousavi and Hideto Matsuyama
Membranes 2021, 11(11), 884; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110884 - 17 Nov 2021
Cited by 11 | Viewed by 2680
Abstract
Hollow fiber membranes (HFMs) possess desired properties such as high surface area, desirable filtration efficiency, high packing density relative to other configurations. Nevertheless, they are often possible to break or damage during the high-pressure cleaning and aeration process. Recently, using the braid reinforcing [...] Read more.
Hollow fiber membranes (HFMs) possess desired properties such as high surface area, desirable filtration efficiency, high packing density relative to other configurations. Nevertheless, they are often possible to break or damage during the high-pressure cleaning and aeration process. Recently, using the braid reinforcing as support is recommended to improve the mechanical strength of HFMs. The braid hollow fiber membrane (BHFM) is capable apply under higher pressure conditions. This review investigates the fabrication parameters and the methods for the improvement of BHFM performance. Full article
(This article belongs to the Special Issue Hollow Fiber Membranes and Their Applications)
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14 pages, 1418 KiB  
Article
An Assessment of Renewable Energies in a Seawater Desalination Plant with Reverse Osmosis Membranes
by Federico Leon and Alejandro Ramos
Membranes 2021, 11(11), 883; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110883 - 17 Nov 2021
Cited by 4 | Viewed by 1806
Abstract
The purpose of our study was to reduce the carbon footprint of seawater desalination plants that use reverse osmosis membranes by introducing on-site renewable energy sources. By using new-generation membranes with a low energy consumption and considering wind and photovoltaic energy sources, it [...] Read more.
The purpose of our study was to reduce the carbon footprint of seawater desalination plants that use reverse osmosis membranes by introducing on-site renewable energy sources. By using new-generation membranes with a low energy consumption and considering wind and photovoltaic energy sources, it is possible to greatly reduce the carbon footprint of reverse osmosis plants. The objective of this study was to add a renewable energy supply to a desalination plant that uses reverse osmosis technology. During the development of this research study, photovoltaic energy was discarded as a possible source of renewable energy due to the wind conditions in the area in which the reverse osmosis plant was located; hence, the installation of a wind turbine was considered to be the best option. As it was a large-capacity reverse osmosis plant, we decided to divide the entire desalination process into several stages for explanation purposes. The desalination process of the facility consists of several phases: First, the seawater capture process was performed by the intake tower. This water was then transported and stored, before going through a physical and chemical pre-treatment process, whereby the highest possible percentage of impurities and organic material was eliminated in order to prevent the plugging of the reverse osmosis modules. After carrying out the appraisals and calculating the amount of energy that the plant consumed, we determined that 15% of the plant’s energy supply should be renewable, corresponding to 1194 MWh/year. As there was already a wind power installation in the area, we decided to use one of the wind turbines that had already been installed—specifically, an Ecotecnia turbine (20–150) that produced an energy of 1920 MWh /year. This meant that only a single wind turbine was required for this project. Full article
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11 pages, 1642 KiB  
Review
Plasma Membrane Lipids: An Important Binding Site for All Lipoprotein Classes
by Markus Axmann, Birgit Plochberger, Mario Mikula, Florian Weber, Witta Monika Strobl and Herbert Stangl
Membranes 2021, 11(11), 882; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110882 - 17 Nov 2021
Cited by 2 | Viewed by 2061
Abstract
Cholesterol is one of the main constituents of plasma membranes; thus, its supply is of utmost importance. This review covers the known mechanisms of cholesterol transfer from circulating lipoprotein particles to the plasma membrane, and vice versa. To achieve homeostasis, the human body [...] Read more.
Cholesterol is one of the main constituents of plasma membranes; thus, its supply is of utmost importance. This review covers the known mechanisms of cholesterol transfer from circulating lipoprotein particles to the plasma membrane, and vice versa. To achieve homeostasis, the human body utilizes cellular de novo synthesis and extracellular transport particles for supply of cholesterol and other lipids via the blood stream. These lipoprotein particles can be classified according to their density: chylomicrons, very low, low, and high-density lipoprotein (VLDL, LDL, and HDL, respectively). They deliver and receive their lipid loads, most importantly cholesterol, to and from cells by several redundant routes. Defects in one of these pathways (e.g., due to mutations in receptors) usually are not immediately fatal. Several redundant pathways, at least temporarily, compensate for the loss of one or more of them, but the defects trigger systemic diseases, such as atherosclerosis later on. Recently, intracellular membrane–membrane contact sites were shown to be involved in intracellular cholesterol transfer and the plasma membrane itself has been proposed to act as a binding site for lipoprotein-mediated cargo unloading. Full article
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12 pages, 3889 KiB  
Article
Formation of Water-Channel by Propylene Glycol into Polymer for Porous Materials
by Seong Ho Hong, Younghyun Cho and Sang Wook Kang
Membranes 2021, 11(11), 881; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110881 - 16 Nov 2021
Cited by 8 | Viewed by 1630
Abstract
In this study, a porous membrane with a cellulose acetate (CA) matrix was fabricated using propylene glycol with a water pressure treatment without a metal salt as an additive. The water pressure treatment of the fabricated CA membrane with propylene glycol yielded nanopores. [...] Read more.
In this study, a porous membrane with a cellulose acetate (CA) matrix was fabricated using propylene glycol with a water pressure treatment without a metal salt as an additive. The water pressure treatment of the fabricated CA membrane with propylene glycol yielded nanopores. The nanopores were formed as the additives in the CA chains led to plasticization. The weakened chains of the parts where the plasticization occurred were broken by the water pressure, which generated the pores. Compared to the previous study with glycerin as an additive, the size of the hydration region was controlled by the number of hydrophilic functional groups. When water pressure was applied to the CA membrane containing propylene glycol as an additive, the hydration area was small, so it was effective to control the pore size and the number of nano pores than glycerin. In addition, the number of nanopores and pore size could be easily adjusted by the water pressure. The porosity of the membrane was increased owing to the trace amount of propylene glycol, confirmed by scanning electron microscopy (SEM) and porosimetry. The interaction between the CA and propylene glycol was verified by Fourier-transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). Consequently, it was the optimum composition to generate pores at the CA/propylene glycol 1:0.2 ratio, and porosity of 69.7% and average pore diameter of 300 nm was confirmed. Since it is a membrane with high porosity and nano sized pores, it is expected to be applied in various fields. Full article
(This article belongs to the Special Issue State-of-the-Art Mixed Matrix Membranes (MMMs))
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18 pages, 3956 KiB  
Article
Dynamic Landscape of Extracellular Vesicle-Associated Proteins Is Related to Treatment Response of Patients with Metastatic Breast Cancer
by Olivia Ruhen, Xinyu Qu, M. Fairuz B. Jamaluddin, Carlos Salomon, Aesha Gandhi, Michael Millward, Brett Nixon, Matthew D. Dun and Katie Meehan
Membranes 2021, 11(11), 880; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110880 - 16 Nov 2021
Cited by 4 | Viewed by 2371
Abstract
Breast cancer is the leading cause of cancer death in women. The majority of these deaths are due to disease metastasis, in which cancer cells disseminate to multiple organs and disrupt vital physiological functions. It is widely accepted that breast cancer cells secrete [...] Read more.
Breast cancer is the leading cause of cancer death in women. The majority of these deaths are due to disease metastasis, in which cancer cells disseminate to multiple organs and disrupt vital physiological functions. It is widely accepted that breast cancer cells secrete extracellular vesicles (EVs), which contain dynamic molecular cargo that act as versatile mediators of intercellular communication. Therefore, Evs. secreted by breast cancer cells could be involved in the development of metastatic disease and resistance to treatment. Moreover, changes in EV cargo could reflect the effects of therapy on their parent tumor cells. The aim of this feasibility study was to quantitatively profile the proteomes of Evs. isolated from blood samples taken from treatment sensitive and resistant metastatic breast cancer patients to identify proteins associated with responses. Three serial blood samples were collected from three patients with metastatic breast cancer receiving systemic therapy including a responder, a non-responder, and a mixed-responder. Evs. were isolated from plasma using size exclusion chromatography and their protein cargo was prepared for tandem mass tag (TMT)-labelling and quantitative analyses using two-dimensional high-performance liquid chromatography followed by tandem mass spectrometry. After filtering, we quantitatively identified 286 proteins with high confidence using a q value of 0.05. Of these, 149 were classified as EV associated candidate proteins and 137 as classical, high abundant plasma proteins. After comparing EV protein abundance between the responder and non-responder, we identified 35 proteins with unique de-regulated abundance patterns that was conserved at multiple time points. We propose that this proof-of-concept approach can be used to identify proteins which have potential as predictors of metastatic breast cancer response to treatment. Full article
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33 pages, 3332 KiB  
Review
Preparation, Performance and Challenges of Catalyst Layer for Proton Exchange Membrane Fuel Cell
by Meng Xie, Tiankuo Chu, Tiantian Wang, Kechuang Wan, Daijun Yang, Bing Li, Pingwen Ming and Cunman Zhang
Membranes 2021, 11(11), 879; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110879 - 15 Nov 2021
Cited by 28 | Viewed by 8386
Abstract
In this paper, the composition, function and structure of the catalyst layer (CL) of a proton exchange membrane fuel cell (PEMFC) are summarized. The hydrogen reduction reaction (HOR) and oxygen reduction reaction (ORR) processes and their mechanisms and the main interfaces of CL [...] Read more.
In this paper, the composition, function and structure of the catalyst layer (CL) of a proton exchange membrane fuel cell (PEMFC) are summarized. The hydrogen reduction reaction (HOR) and oxygen reduction reaction (ORR) processes and their mechanisms and the main interfaces of CL (PEM|CL and CL|MPL) are described briefly. The process of mass transfer (hydrogen, oxygen and water), proton and electron transfer in MEA are described in detail, including their influencing factors. The failure mechanism of CL (Pt particles, CL crack, CL flooding, etc.) and the degradation mechanism of the main components in CL are studied. On the basis of the existing problems, a structure optimization strategy for a high-performance CL is proposed. The commonly used preparation processes of CL are introduced. Based on the classical drying theory, the drying process of a wet CL is explained. Finally, the research direction and future challenges of CL are pointed out, hoping to provide a new perspective for the design and selection of CL materials and preparation equipment. Full article
(This article belongs to the Special Issue Membrane Electrode Assembly (MEA))
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14 pages, 2619 KiB  
Article
Quantitative Super-Resolution Microscopy to Assess Adhesion of Neuronal Cells on Single-Layer Graphene Substrates
by Silvia Scalisi, Francesca Pennacchietti, Sandeep Keshavan, Nathan D. Derr, Alberto Diaspro, Dario Pisignano, Agnieszka Pierzynska-Mach, Silvia Dante and Francesca Cella Zanacchi
Membranes 2021, 11(11), 878; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110878 - 15 Nov 2021
Cited by 3 | Viewed by 2314
Abstract
Single Layer Graphene (SLG) has emerged as a critically important nanomaterial due to its unique optical and electrical properties and has become a potential candidate for biomedical applications, biosensors, and tissue engineering. Due to its intrinsic 2D nature, SLG is an ideal surface [...] Read more.
Single Layer Graphene (SLG) has emerged as a critically important nanomaterial due to its unique optical and electrical properties and has become a potential candidate for biomedical applications, biosensors, and tissue engineering. Due to its intrinsic 2D nature, SLG is an ideal surface for the development of large-area biosensors and, due to its biocompatibility, can be easily exploited as a substrate for cell growth. The cellular response to SLG has been addressed in different studies with high cellular affinity for graphene often detected. Still, little is known about the molecular mechanism that drives/regulates the cellular adhesion and migration on SLG and SLG-coated interfaces with respect to other substrates. Within this scenario, we used quantitative super-resolution microscopy based on single-molecule localization to study the molecular distribution of adhesion proteins at the nanoscale level in cells growing on SLG and glass. In order to reveal the molecular mechanisms underlying the higher affinity of biological samples on SLG, we exploited stochastic optical reconstruction microscopy (STORM) imaging and cluster analysis, quantifying the super-resolution localization of the adhesion protein vinculin in neurons and clearly highlighting substrate-related correlations. Additionally, a comparison with an epithelial cell line (Chinese Hamster Ovary) revealed a cell dependent mechanism of interaction with SLG. Full article
(This article belongs to the Special Issue Nanoscale Membranes Structure and Dynamics)
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4 pages, 191 KiB  
Editorial
Membrane Surface Modification and Functionalization
by Vivek Vasagar, Mohammad K. Hassan and Majeda Khraisheh
Membranes 2021, 11(11), 877; https://0-doi-org.brum.beds.ac.uk/10.3390/membranes11110877 - 15 Nov 2021
Cited by 4 | Viewed by 1814
Abstract
With the increase in water scarcity, and as only 2 [...] Full article
(This article belongs to the Special Issue Membrane Surface Modification and Functionalization)
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