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1.
Environ Monit Assess ; 193(8): 460, 2021 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-34216274

RESUMO

Copper ion removal with nanofiltration membranes has accelerated in recent years. In this study, Cu2+ ion removal was investigated with nanofiltration membrane and a membrane capacitive deionization (MCDI) system; consequently, it was observed that the highest performance was seen when these two systems worked in an integrated system (99% Cu2+ ion removal) MCDI system is a purification technology through ion exchange membranes based on applying an electric field between two opposed electrodes. The flow rate, direct current voltage, and the operation time at which the Cu2+ ion removal rate was the highest were 50 mL/min, 1.2 V, and 15 min. respectively. Here, we report the application of the life cycle assessment (LCA) method to evaluate the environmental performance of the membrane system in different operating conditions. In the sensitivity analysis component of the study, different materials used in the membrane system and MCDI ststem were compared. Results from the LCA analysis showed that the MCDI system has far worse environmental impacts in all aspects particularly in material and energy-related effects.


Assuntos
Purificação da Água , Adsorção , Eletrodos , Monitoramento Ambiental , Íons , Membranas Artificiais , Tecnologia
2.
Am J Case Rep ; 22: e932045, 2021 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-34215716

RESUMO

BACKGROUND Biocompatible hemodialysis membranes have greatly advanced the treatment of renal failure. Synthetic polysulfone dialysis membranes are considered to be very biocompatible because of their low propensity to activate complement. However, these membranes can reduce platelet count through platelet activation, although the mechanism of this activation is unknown. CASE REPORT We report the case of an 82-year-old man with a history of chronic kidney disease with recurrent gastrointestinal bleeding and worsening renal function who was initiated on renal replacement therapy with polysulfone dialysis membranes. On admission, the patient's platelet count was normal at 233×10³/µL. A significant fall in platelet count was observed following most dialysis treatments, reaching a nadir of 37×10³/µL. With occasional dialysis treatments, his platelet count did not change. This dialysis-induced thrombocytopenia resolved following substitution with Cellentia-H cellulose triacetate single-use, hollow-fiber, high-flux hemodialyzer membrane. CONCLUSIONS Polysulfone membranes are capable of activating platelets, which can result in severe thrombocytopenia. However, the magnitude of dialysis-induced thrombocytopenia varies from treatment to treatment. As such, it may not be evident when the pre- and postdialysis platelet counts are measured for a single treatment. Because the etiology of this platelet activation is unknown, substitution with cellulose triacetate membranes should be considered. These membranes have an unrelated chemical composition and a very low propensity to activate platelets.


Assuntos
Diálise Renal , Trombocitopenia , Idoso de 80 Anos ou mais , Materiais Biocompatíveis , Humanos , Masculino , Membranas Artificiais , Polímeros , Sulfonas
3.
Int J Nanomedicine ; 16: 4471-4480, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34234437

RESUMO

Background: Postoperative tissue adhesion is a major concern for most surgeons and is a nearly unpreventable complication after abdominal or pelvic surgeries. This study explored the use of sandwich-structured antimicrobial agents, analgesics, and human epidermal growth factor (hEGF)-incorporated anti-adhesive poly(lactic-co-glycolic acid) nanofibrous membranes for surgical wounds. Materials and Methods: Electrospinning and co-axial electrospinning techniques were utilized in fabricating the membranes. After spinning, the properties of the prepared membranes were assessed. Additionally, high-performance liquid chromatography and enzyme-linked immunosorbent assays were utilized in assessing the in vitro and in vivo liberation profiles of the pharmaceuticals and the hEGF from the membranes. Results: The measured data suggest that the degradable anti-adhesive membranes discharged high levels of vancomycin/ceftazidime, ketorolac, and hEGF in vitro for more than 30, 24, and 27 days, respectively. The in vivo assessment in a rat laparotomy model indicated no adhesion in the peritoneal cavity at 14 days post-operation, demonstrating the anti-adhesive capability of the sandwich-structured nanofibrous membranes. The nanofibers also released effective levels of vancomycin, ceftazidime, and ketorolac for more than 28 days in vivo. Histological examination revealed no adverse effects. Conclusion: The outcomes of this study implied that the anti-adhesive nanofibers with sustained release of antimicrobial agents, analgesics, and growth factors might offer postoperative pain relief and infection control, as well as promote postoperative healing of surgical wounds.


Assuntos
Analgésicos/farmacologia , Anti-Infecciosos/farmacologia , Família de Proteínas EGF/metabolismo , Membranas Artificiais , Nanofibras/química , Copolímero de Ácido Poliláctico e Ácido Poliglicólico/química , Adesividade/efeitos dos fármacos , Analgésicos/química , Animais , Anti-Infecciosos/química , Humanos , Ratos , Ferida Cirúrgica/fisiopatologia , Cicatrização/efeitos dos fármacos
4.
Int J Mol Sci ; 22(11)2021 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-34072512

RESUMO

Synthetic materials commonly used in the packaging industry generate a considerable amount of waste each year. Chitosan is a promising feedstock for the production of functional biomaterials. From a biological point of view, chitosan is very attractive for food packaging. The purposes of this study were to evaluate the antibacterial activity of a set of chitosan-metal oxide films and different chitosan-modified graphene (oxide) films against two foodborne pathogens: Campylobacter jejuni ATCC 33560 and Listeria monocytogenes 19115. Moreover, we wanted to check whether the incorporation of antimicrobial constituents such as TiO2, ZnO, Fe2O3, Ag, and graphene oxide (GO) into the polymer matrices can improve the antibacterial properties of these nanocomposite films. Finally, this research helps elucidate the interactions of these materials with eukaryotic cells. All chitosan-metal oxide films and chitosan-modified graphene (oxide) films displayed improved antibacterial (C. jejuni ATCC 33560 and L. monocytogenes 19115) properties compared to native chitosan films. The CS-ZnO films had excellent antibacterial activity towards L. monocytogenes (90% growth inhibition). Moreover, graphene-based chitosan films caused high inhibition of both tested strains. Chitosan films with graphene (GO, GOP, GOP-HMDS, rGO, GO-HMDS, rGOP), titanium dioxide (CS-TiO2 20:1a, CS-TiO2 20:1b, CS-TiO2 2:1, CS-TiO2 1:1a, CS-TiO2 1:1b) and zinc oxide (CS-ZnO 20:1a, CS-ZnO 20:1b) may be considered as a safe, non-cytotoxic packaging materials in the future.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Materiais Biocompatíveis , Quitosana , Microbiologia de Alimentos , Embalagem de Alimentos , Membranas Artificiais , Antibacterianos/química , Antibacterianos/farmacologia , Membrana Externa Bacteriana/efeitos dos fármacos , Permeabilidade da Membrana Celular/efeitos dos fármacos , Quitosana/química , Metais/química , Polímeros
5.
Chemosphere ; 279: 130524, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34134401

RESUMO

This paper deals with the membrane fouling issue in the Direct Contact Membrane Distillation (DCMD) process treating a wasted sludge from an anaerobic digestion process. The main objective is to define an optimal cleaning strategy to alleviate fouling. Using a lab scale DCMD process, a cleaning strategy based on DI water flushing followed by 0.2% sodium hypochlorite (NaOCl) and 3% citric acid (C6H8O7) cleaning was tested with different cleaning frequencies and various chemical cleaning durations at different cross-flow velocities. To avoid severe fouling, the optimal cross-flow velocity was found at 0.18 m/s (0.8 L/min). Moreover, even if higher cross-flow velocity allows higher flux, it could increase fouling risks. For a better membrane regeneration and process productivity, a cleaning of 60 min duration for each chemical cleaning applied every two days was defined as the optimal cleaning strategy. Such conditions allowed the preservation of 75.5% of the initial flux after 96 h of operation. Furthermore, the effect on membrane flux regeneration of DI water flushing, sodium hypochlorite, and citric acid cleaning registered were, 31.52%, 11.95% and 20.65%, respectively. This study revealed that in the MD process treating real wastewater both external and internal fouling are responsible of permeate flux decline due to the accumulation of organic and inorganic matter on the membrane surface as well as within the pores.


Assuntos
Destilação , Purificação da Água , Anaerobiose , Membranas Artificiais , Águas Residuárias
6.
Chemosphere ; 279: 130616, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34134415

RESUMO

In this study, first, graphitic carbon nitride was treated with hydrogen peroxide (abbreviated as H2O2-g-C3N4), then was used as a new hydrophilic nanomaterial in the fabrication of polyethersulfone (PES) mixed matrix membrane (MMM) for improving flux, protein and dye separation efficiency and antifouling properties. The H2O2-g-C3N4 nanosheet was inserted into the doping solution to fabricate PES/H2O2-g-C3N4 nanocomposite membrane with the non-solvent induced phase inversion procedure. The results of the SEM and AFM images and also porosity and contact angle analysis were indicated that the modified membranes with H2O2-g-C3N4 had more porosity, smoother surface and more hydrophilic. Also, the influence of various weight percentage of H2O2-g-C3N4 was investigated systematically on the membrane performance. By blending of H2O2-g-C3N4 nanosheet in the membrane matrix, the permeability was raised from 4.1 (for bare membrane) to 30.1 L m-2 h-1 bar-1. Additionally, the effect of the H2O2-g-C3N4 material on the antifouling features indicated that the flux recover ratio of the H2O2-g-C3N4 MMMs was improved and the resistance parameters were reduced. Also, the effect of the H2O2-g-C3N4 material on the antifouling features indicated that the flux recover ratio of the H2O2-g-C3N4 MMMs was improved and the resistance parameters were reduced. Finally, the dye rejection efficiency of the nanocomposite membranes for Orange II and Reactive Yellow 168 was improved. As a result, it could be mentioned that the mixing low amount of H2O2-g-C3N4 in the membrane structure could significantly improve the membrane flux and antifouling properties without reduction in membrane rejection efficiency.


Assuntos
Incrustação Biológica , Peróxido de Hidrogênio , Incrustação Biológica/prevenção & controle , Membranas Artificiais , Permeabilidade , Polímeros , Sulfonas
7.
Langmuir ; 37(24): 7591-7599, 2021 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-34106713

RESUMO

The forward osmosis (FO) process suffers from unfavorable internal concentration polarization (ICP) of the solute within the support layer of thin-film composite forward osmosis (TFC-FO) membranes. To lower the ICP effect, a support layer with low tortuosity, high porosity, and interconnected pores is necessary. In the present investigation, sodium bicarbonate has been presented as a simple pore-forming agent to decline the ICP within a poly(ethersulfone) substrate. In particular, the porous poly(ethersulfone) support layer was fabricated by embedding sodium bicarbonate into the casting solution to form CO2 gas bubbles in the substrate during phase inversion in an acidic nonsolvent. Experimental results revealed that the separation performance of the TFC-FO membranes significantly improved. The most water-permeable membrane was prepared in the acidic nonsolvent (TFC-SB.3) and it demonstrated a water flux of 26.6 LMH and a reverse salt flux of 3.6 gMH in the FO test. In addition, the TFC-SB.3 membrane showed an 85% increase in water permeability (2.13 LMH/bar) with negligible change in salt rejection (94.3%). Such observations were based on the increase of substrate porosity and the improved connectivity of the finger-like channels through in situ CO2 gas bubbling that alleviate the ICP phenomena. Therefore, the current study presents a simple, scalable method to design a high-performance TFC-FO membrane.


Assuntos
Bicarbonato de Sódio , Purificação da Água , Membranas Artificiais , Osmose , Permeabilidade
8.
Toxins (Basel) ; 13(6)2021 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-34073439

RESUMO

Chronic kidney disease (CKD) is characterized by the retention of solutes named uremic toxins, which strongly associate with high morbidity and mortality. Mounting evidence suggests that targeting uremic toxins and/or their pathways may decrease the risk of cardiovascular disease in CKD patients. Dialysis therapies have been developed to improve removal of uremic toxins. Advances in our understanding of uremic retention solutes as well as improvements in dialysis membranes and techniques (HDx, Expanded Hemodialysis) will offer the opportunity to ameliorate clinical symptoms and outcomes, facilitate personalized and targeted dialysis treatment, and improve quality of life, morbidity and mortality.


Assuntos
Diálise Renal/métodos , Insuficiência Renal Crônica/terapia , Toxinas Biológicas/metabolismo , Uremia/metabolismo , Humanos , Membranas Artificiais , Qualidade de Vida , Insuficiência Renal Crônica/psicologia , Albumina Sérica/metabolismo
9.
J Dairy Sci ; 104(8): 8630-8643, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34099299

RESUMO

Our objective was to measure whey protein removal percentage from separated sweet whey using spiral-wound (SW) polymeric microfiltration (MF) membranes using a 3-stage, 3× process at 50°C and to compare the performance of polymeric membranes with ceramic membranes. Pasteurized, separated Cheddar cheese whey (1,080 kg) was microfiltered using a polymeric 0.3-µm polyvinylidene (PVDF) fluoride SW membrane and a 3×, 3-stage MF process. Cheese making and whey processing were replicated 3 times. There was no detectable level of lactoferrin and no intact α- or ß-casein detected in the MF permeate from the 0.3-µm SW PVDF membranes used in this study. We found BSA and IgG in both the retentate and permeate. The ß-lactoglobulin (ß-LG) and α-lactalbumin (α-LA) partitioned between retentate and permeate, but ß-LG passage through the membrane was retarded more than α-LA because the ratio of ß-LG to α-LA was higher in the MF retentate than either in the sweet whey feed or the MF permeate. About 69% of the crude protein present in the pasteurized separated sweet whey was removed using a 3×, 3-stage, 0.3-µm SW PVDF MF process at 50°C compared with 0.1-µm ceramic graded permeability MF that removed about 85% of crude protein from sweet whey. The polymeric SW membranes used in this study achieve approximately 20% lower yield of whey protein isolate (WPI) and a 50% higher yield of whey protein phospholipid concentrate (WPPC) under the same MF processing conditions as ceramic MF membranes used in the comparison study. Total gross revenue from the sale of WPI plus WPPC produced with polymeric versus ceramic membranes is influenced by both the absolute market price for each product and the ratio of market price of these 2 products. The combination of the market price of WPPC versus WPI and the influence of difference in yield of WPPC and WPI produced with polymeric versus ceramic membranes yielded a price ratio of WPPC versus WPI of 0.556 as the cross over point that determined which membrane type achieves higher total gross revenue return from production of these 2 products from separated sweet whey. A complete economic engineering study comparison of the WPI and WPPC manufacturing costs for polymeric versus ceramic MF membranes is needed to determine the effect of membrane material selection on long-term processing costs, which will affect net revenue and profit when the same quantity of sweet whey is processed under various market price conditions.


Assuntos
Filtração , Soro do Leite , Animais , Proteínas Sanguíneas , Filtração/veterinária , Manipulação de Alimentos , Membranas Artificiais , Leite , Proteínas do Leite , Proteínas do Soro do Leite
10.
Colloids Surf B Biointerfaces ; 205: 111886, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34091371

RESUMO

Guided bone regeneration (GBR) is widely used to treat oral bone defects. However, the osteogenic effects are limited by the deficiency of the available barrier membranes. In this study, a novel bi-layer membrane was prepared by solvent casting and electrospinning. The barrier layer made of poly (lactic-co-glycolic acid) (PLGA) was smooth and compact, whereas the osteogenic layer consisting of micro-nano bioactive glass (MNBG) and PLGA was rough and porous. The mineralization evaluation confirmed that apatite formed on the membranes in simulated body fluid. Immersion in phosphate-buffered saline led to the degradation of the membranes with proper pH changes. Mechanical tests showed that the bi-layered membranes have stable mechanical properties under dry and wet conditions. The bi-layered membranes have good histocompatibility, and the MNBG/PLGA layer can enhance bone regeneration activity. This was confirmed by cell culture results, expression of osteogenic genes, and immunofluorescence staining of RUNX-related transcription factor 2 and osteopontin. Therefore, the bi-layered membranes could be a promising clinical strategy for GBR surgery.


Assuntos
Materiais Biocompatíveis , Regeneração Tecidual Guiada , Materiais Biocompatíveis/farmacologia , Regeneração Óssea , Vidro , Membranas Artificiais , Osteogênese , Porosidade
11.
Colloids Surf B Biointerfaces ; 205: 111889, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34098365

RESUMO

The composition of Langmuir monolayers used as cell membrane models is an essential factor for the interaction with biologically-relevant molecules, including pharmaceutical drugs. In this paper, we report the modulation of effects from the antineoplastic drug paclitaxel by the relative concentration of cholesterol in the Langmuir monolayers of ternary mixtures of dipalmitoylphosphatidylcholine, sphingomyelin, and cholesterol. Since the dependence on cholesterol concentration for these monolayers simulating lipid rafts is non-monotonic, we analyzed the surface pressure and compressibility modulus data with the multidimensional projection technique referred to as interactive document mapping (IDMAP). The maximum expansion induced by paclitaxel in surface pressure isotherms was observed for 27% cholesterol, while the compressibility modulus decreased most strongly for the monolayer with 48% cholesterol. Therefore, the physiological action of paclitaxel may vary depending on whether it is associated with penetration in the membrane or with changes in the membrane elasticity.


Assuntos
1,2-Dipalmitoilfosfatidilcolina , Paclitaxel , Membrana Celular , Colesterol , Membranas Artificiais , Esfingomielinas
12.
Colloids Surf B Biointerfaces ; 205: 111867, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34120090

RESUMO

This study aims to investigate the modification of polyethersulfone (PES) membrane with boron nitride quantum dots (BNQD) for improving the antifouling performance. The composite membranes were synthesized by blending different amounts of BNQD (0.50, 1.00, and 2.00 wt.%) into PES with the non-solvent induced phase separation (NIPS) method. UV-vis absorption, X-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to characterize BNQD. Moreover, porosity, pore size, contact angle, permeability, bovine serum albumin (BSA) rejection, and antifouling properties were determined for composite membranes. The enhanced biological activity of BNQD was investigated based on antioxidant, antimicrobial, anti-biofilm, bacterial viability inhibition, and DNA cleavage studies. The BNQD showed 19.35 % DPPH radical scavenging activity and 76.45 % ferrous ion chelating activity at 500 mg/L. They also exhibited good chemical nuclease activity at all concentrations. BNQD had moderate antibacterial activity against all tested microorganisms. Biofilm inhibition percentage of BNQD was determined as 82.31 % at 500 mg/L. Cell viability assay demonstrated that the BNQD showed strong cell viability inhibition 99.9 % at the concentration of 1000 mg/L. The porosity increased from 56.83 ± 1.17%-61.83 ± 1.17 % while BNQD concentration increased from 0 to 2.00 wt%. Moreover, the hydrophilicity of BNQD nanocomposite membranes also increased from 75.42 ± 0.56° to 65.34 ± 0.25°. The mean pore radius is far slightly changed from 16.47 ± 0.35 nm to 19.16 ± 0.22 nm. The water flux increased from 133.5 ± 9.5 L/m2/h (for pristine membrane) to 388.6 ± 18.8 L/m2/h (for PES/BNQD 2.00 wt% membrane). BSA flux increased from 38.8 ± 0.9 L/m2/h to 63.2 ± 2.7 L/m2/h up to 1.00 wt% amount of BNQD nanoparticles.


Assuntos
Incrustação Biológica , Pontos Quânticos , Incrustação Biológica/prevenção & controle , Compostos de Boro , Membranas Artificiais , Polímeros , Sulfonas , Ultrafiltração
13.
Biomacromolecules ; 22(7): 3005-3016, 2021 07 12.
Artigo em Inglês | MEDLINE | ID: mdl-34105950

RESUMO

Artificial membranes, as materials with biomimetic properties, can be applied in various fields, such as drug screening or bio-sensing. The solvent-assisted method (SA) represents a straightforward method to prepare lipid solid-supported membranes. It overcomes the main limitations of established membrane preparation methods, such as Langmuir-Blodgett (LB) or vesicle fusion. However, it has not yet been applied to create artificial membranes based on amphiphilic block copolymers, despite their enhanced mechanical stability compared to lipid-based membranes and bio-compatible properties. Here, we applied the SA method on different amphiphilic di- and triblock poly(dimethylsiloxane)-block-poly(2-methyl-2-oxazoline) (PDMS-b-PMOXA) copolymers and optimized the conditions to prepare artificial membranes on a solid support. The real-time membrane formation, the morphology, and the mechanical properties have been evaluated by a combination of atomic force microscopy and quartz crystal microbalance. Then, selected biomolecules including complementary DNA strands and an artificial deallylase metalloenzyme (ADAse) were incorporated into these membranes relying on the biotin-streptavidin technology. DNA strands served to establish the capability of these synthetic membranes to interact with biomolecules by preserving their correct conformation. The catalytic activity of the ADAse following its membrane anchoring induced the functionality of the biomimetic platform. Polymer membranes on solid support as prepared by the SA method open new opportunities for the creation of artificial membranes with tailored biomimetic properties and functionality.


Assuntos
Membranas Artificiais , Polímeros , Microscopia de Força Atômica , Solventes
14.
Macromol Rapid Commun ; 42(13): e2100077, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34061421

RESUMO

Herein, the fabrication of iron-containing porous polyelectrolyte membranes (PPMs) via ionic complexation between an imidazolium-based poly(ionic liquid) (PIL) and 1,1-ferrocenedicarboxylic acid is reported. The key parameters to control the microstructure of porous hybrid membranes are investigated in detail. Further aerobic pyrolysis of such porous hybrid membranes at 900 °C can transfer the ferrocene-containing PPMs into freestanding porous iron oxide films. This process points out a sacrificial template function of porous poly(ionic liquid) membranes in the fabrication of porous metal oxide films.


Assuntos
Líquidos Iônicos , Compostos Férricos , Membranas Artificiais , Metalocenos , Porosidade
15.
Sci Total Environ ; 784: 147157, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34088054

RESUMO

The present work compares the chemical properties of isolated biopolymers of different origins and their fouling potential during ultrafiltration (UF). The biopolymers were extracted from secondary wastewater effluent as effluent organic matter (EfOM) and from surface water as natural organic matter (NOM). Multiple analytical techniques were used to characterize the isolates. The characterization results revealed that EfOM biopolymers were more enriched in protein-type structures compared to the NOM organics, and they presented significant differences in the reversibility of membrane fouling. Dissolved in pure water, EfOM biopolymers led to more irreversible fouling than that caused by NOM isolates. Dosing divalent cations (e.g., Ca2+) into the solutions increased the irreversibility of both types of fouling, while aggravating NOM fouling more significantly. Further investigation was conducted to understand the interaction between EfOM and NOM biopolymers during formation of the fouling layer. The results showed that the interaction between these two types of organics was negligible in the absence of salts. These findings highlight the importance of a comprehensive understanding of biopolymers from different origins, considering their chemical properties and water chemistry, which have valuable implications for selecting suitable membrane fouling control strategies for treating water from different origins.


Assuntos
Ultrafiltração , Purificação da Água , Biopolímeros , Membranas Artificiais , Águas Residuárias
16.
Mater Sci Eng C Mater Biol Appl ; 126: 112127, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082944

RESUMO

Hemodialysis considered as therapy of end-stage renal disease (ESRD) for the separation of protein and uremic toxins based on their molecular weights using semi-permeable membranes. Cellulose Acetate (CA) hemodialysis membrane has been widely used in the biomedical field particularly for hemodialysis applications. The main issue of CA membrane is less selectivity and hemocompatibility. In this study, to enhance the filtration capability and biocompatibility of CA hemodialysis membrane modified by using Polyvinyl Alcohol (PVA) and Polyethylene Glycol (PEG) as additives. CA-PVA flat sheet membranes were cast by phase inversion method, and separation was done by dead-end filtration cell. The synthesized membranes were described in terms of chemical structure using Fourier Transform Infrared Spectroscopy (FTIR) and morphology by Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), pure water flux, solute permeation, and protein retention. Biocompatibility of the membranes was tested by the platelet adherence, hemolysis ratio, thrombus formation, and plasma recalcification time. SEM images exposed that the CA-PVA membrane has a uniform porous structure. 42.484 L/m2 h is the maximum pure water flux obtained. The CA-PVA rejected up to 95% of bovine serum albumin (BSA). A similar membrane separated 93% of urea and 89% of creatinine. Platelet adhesion and hemolysis ratio of casted membranes were less than the pure CA membrane. Increased clotting time and less thrombus formation on the membrane's surface showed that the fabricated membrane is biocompatible. CA-PVA hemodialysis membranes are more efficient than conventional reported hemodialysis membranes. It revealed that CA-PVA is high performing biocompatible hemodialysis membrane.


Assuntos
Membranas Artificiais , Álcool de Polivinil , Celulose/análogos & derivados , Diálise Renal
17.
Mater Sci Eng C Mater Biol Appl ; 126: 112180, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34082980

RESUMO

Many research groups have investigated the various kinds of scaffolds to mimic the natural Bruch's membrane (BM) and support the retinal pigmented epithelial cells to form an organized cellular monolayer. While using prosthetic BM is identified as a promising treatment of age-related macular degeneration (AMD), a degenerative and progressive retinal disease, the effects of different signals such as electrical and morphological cues on the retinal pigmented epithelial (RPE) cells are still unknown. In this study, a laminated and conductive hydrogel/fiber composite scaffold by adding conductive polyaniline (PANi) to the scaffold's nanofibrous phase was prepared. This hybrid scaffold offers the closest morphology to the native structure of the human Bruch's membrane by imitating the inner and outer collagenous layer and induces the electrical signal to the scaffold to assess the electrical cue on behaviors of polarized retinal pigmented epithelial cells in the retina. The electrospun nanofibrous phase consisted of gelatin-Polyaniline in different ratios incorporated into the hydrogel precursor, a blend of gelatin and 4-armed PEG. We used a novel dual crosslinking process by incorporating the exposure of gamma irradiation and glutaraldehyde vapor treatment to construct the scaffold's hydrogel phase. The results showed the best composition was the sample which included the 40/60, Polyaniline/gelatin nanofiber sheets ratio because this scaffold revealed a 2.66 ± 0.33 MPa, Young's modulus and 1.84 ± 0.21 S/cm, electrochemical conductivity, which are close to the main features of native Bruch's membrane. In addition, this scaffold showed good biocompatibility by reaching 83.47% cell viability.


Assuntos
Lâmina Basilar da Corioide , Nanofibras , Gelatina , Humanos , Membranas Artificiais , Retina
18.
Int J Nanomedicine ; 16: 3661-3678, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34093011

RESUMO

Introduction: Brain ischemia is a common neurological disorder worldwide that activates a cascade of pathophysiological events involving decreases in oxygen and glucose levels. Despite substantial efforts to explore its pathogenesis, the management of ischemic neuronal injury remains an enormous challenge. Accumulating evidence suggests that VEGF modified nanofiber (NF) materials and the fatty-acid amide hydrolase (FAAH) inhibitor URB597 exert an influence on alleviating ischemic brain damage. We aimed to further investigate their effects on primary hippocampal neurons, as well as the underlying mechanisms following oxygen-glucose deprivation (OGD). Methods: Different layers of VEGF-A loaded polycaprolactone (PCL) nanofibrous membranes were first synthesized by using layer-by-layer (LBL) self-assembly of electrospinning methods. The physicochemical and biological properties of VEGF-A NF membranes, and their morphology, hydrophilicity, and controlled-release of VEGF-A were then estimated. Furthermore, the effects of VEGF-A NF and URB597 on OGD-induced mitochondrial oxidative stress, inflammatory responses, neuronal apoptosis, and endocannabinoid signaling components were assessed. Results: The VEGF-A NF membrane and URB597 can not only promote hippocampal neuron adhesion and viability following OGD but also exhibited antioxidant/anti-inflammatory and mitochondrial membrane potential protection. The VEGF-A NF membrane and URB597 also inhibited OGD-induced cellular apoptosis through activating CB1R signaling. These results indicate that VEGF-A could be controlled-released by LBL self-assembled NF membranes. Discussion: The VEGF-A NF membrane and URB597 displayed positive synergistic neuroprotective effects through the inhibition of mitochondrial oxidative stress and activation of CB1R/PI3K/AKT/BDNF signaling, suggesting that a VEGF-A loaded NF membrane and the FAAH inhibitor URB597 could be of therapeutic value in ischemic cerebrovascular diseases.


Assuntos
Benzamidas/farmacologia , Carbamatos/farmacologia , Nanofibras/química , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Fator A de Crescimento do Endotélio Vascular/farmacologia , Amidoidrolases/antagonistas & inibidores , Amidoidrolases/metabolismo , Animais , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/metabolismo , Isquemia Encefálica/patologia , Células Cultivadas , Endocanabinoides/metabolismo , Glucose/metabolismo , Hipocampo/efeitos dos fármacos , Hipocampo/patologia , Membranas Artificiais , Neurônios/metabolismo , Neurônios/patologia , Oxigênio/metabolismo , Ratos Sprague-Dawley , Fator A de Crescimento do Endotélio Vascular/química
19.
Int J Mol Sci ; 22(11)2021 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-34063925

RESUMO

Today, the use of polymer electrolyte membranes (PEMs) possessing ionic liquids (ILs) in middle and high temperature polymer electrolyte membrane fuel cells (MT-PEMFCs and HT-PEMFCs) have been increased. ILs are the organic salts, and they are typically liquid at the temperature lower than 100 °C with high conductivity and thermal stability. The membranes containing ILs can conduct protons through the PEMs at elevated temperatures (more than 80 °C), unlike the Nafion-based membranes. A wide range of ILs have been identified, including chiral ILs, bio-ILs, basic ILs, energetic ILs, metallic ILs, and neutral ILs, that, from among them, functionalized ionic liquids (FILs) include a lot of ion exchange groups in their structure that improve and accelerate proton conduction through the polymeric membrane. In spite of positive features of using ILs, the leaching of ILs from the membranes during the operation of fuel cell is the main downside of these organic salts, which leads to reducing the performance of the membranes; however, there are some ways to diminish leaching from the membranes. The aim of this review is to provide an overview of these issues by evaluating key studies that have been undertaken in the last years in order to present objective and comprehensive updated information that presents the progress that has been made in this field. Significant information regarding the utilization of ILs in MT-PEMFCs and HT-PEMFCs, ILs structure, properties, and synthesis is given. Moreover, leaching of ILs as a challenging demerit and the possible methods to tackle this problem are approached in this paper. The present review will be of interest to chemists, electrochemists, environmentalists, and any other researchers working on sustainable energy production field.


Assuntos
Eletrólitos/química , Líquidos Iônicos/química , Polímeros/química , Animais , Condutividade Elétrica , Temperatura Alta , Humanos , Membranas Artificiais , Prótons
20.
Int J Mol Sci ; 22(11)2021 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-34067406

RESUMO

The use of reactive electrochemical membranes (REM) in flow-through mode during the anodic oxidation of organic compounds makes it possible to overcome the limitations of plate anodes: in the case of REM, the area of the electrochemically active surface is several orders of magnitude larger, and the delivery of organic compounds to the reaction zone is controlled by convective flow rather than diffusion. The main problem with REM is the formation of fouling and gas bubbles in the pores, which leads to a decrease in the efficiency of the process because the hydraulic resistance increases and the electrochemically active surface is shielded. This work aims to study the processes underlying the reduction in the efficiency of anodic oxidation, and in particular the formation of gas bubbles and the recharge of the REM pore surface at a current density exceeding the limiting kinetic value. We propose a simple one-dimensional non-stationary model of the transport of diluted species during the anodic oxidation of paracetamol using REM to describe the above effects. The processing of the experimental data was carried out. It was found that the absolute value of the zeta potential of the pore surface decreases with time, which leads to a decrease in the permeate flux due to a reduction in the electroosmotic flow. It was shown that in the solution that does not contain organic components, gas bubbles form faster and occupy a larger pore fraction than in the case of the presence of paracetamol; with an increase in the paracetamol concentration, the gas fraction decreases. This behavior is due to a decrease in the generation of oxygen during the recombination reaction of the hydroxyl radicals, which are consumed in the oxidation reaction of the organic compounds. Because the presence of bubbles increases the hydraulic resistance, the residence time of paracetamol-and consequently its degradation degree-increases, but the productivity goes down. The model has predictive power and, after simple calibration, can be used to predict the performance of REM anodic oxidation systems.


Assuntos
Gases/química , Compostos Orgânicos/química , Eletrodos , Radical Hidroxila/química , Membranas Artificiais , Oxirredução , Poluentes Químicos da Água/química
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