New spin coated multilayer lactate biosensor for acidosis monitoring in continuous flow assisted with an electrochemical pH probe.

A LOx-based electrochemical biosensor for high-level lactate determination was developed. For the construction of the biosensor, chitosan and Nafion layers were integrated by using a spin coating procedure, leading to less porous surfaces in comparison with those recorded after a drop casting procedure. The analytical performance of the resulting biosensor for lactate determination was evaluated in batch and flow regime, displaying satisfactory results in both modes ranging from 0.5 to 20 mM concentration range for assessing the lactic acidosis. Finally, the lactate levels in raw serum samples were estimated using the biosensor developed and verified with a blood gas analyzer. Based on these results, the biosensor developed is promising for its use in healthcare environment, after its proper miniaturization. A pH probe based on common polyaniline-based electrochemical sensor was also developed to assist the biosensor for the lactic acidosis monitoring, leading to excellent results in stock solutions ranging from 6.0 to 8.0 mM and raw plasma samples. The results were confirmed by using two different approaches, blood gas analyzer and pH-meter. Consequently, the lactic acidosis monitoring could be achieved in continuous flow regime using both (bio)sensors.

Repair of parastomal hernias with the intraperitoneal funnel meshes IPST-R and IPST.

The treatment of parastomal hernias (PSH) represents a major challenge in hernia surgery. Various techniques have been reported with different outcomes in terms of complication and recurrence rates. The aim of this study is to share our initial experience with the implantation of the DynaMesh-IPST-R and -IPST, intraperitoneal funnel meshes made of polyvinylidene fluoride (PVDF). This is a retrospective observational cohort study of patients treated for PSH between March 2019 and April 2023 using the chimney technique with the intraperitoneal funnel meshes IPST-R or IPST. The primary outcome was recurrence and the secondary outcomes were intraoperative and postoperative complications, the latter assessed using the Clavien-Dindo classification. A total of 21 consecutive patients were treated with intraperitoneal PVDF funnel meshes, 17 with IPST-R and 4 with IPST. There were no intraoperative complications. Overall, no complications occurred in 61.9% (n = 12) of the patients. Major postoperative complications (defined as Clavien-Dindo ≥ 3b) were noted in four cases (19.0%). During the mean follow-up period of 21.6 (range 4.8-37.5) months, one patient (4.8%) had a recurrence. In conclusion, for the treatment of parastomal hernias, the implantation of IPST-R or IPST mesh has proven to be efficient, easy to handle, and very safe. In particular, the low recurrence rate of 4.8%, which is in line with the current literature, is convincing. However, a larger number of patients would improve the validity of the results.

A novel XYZ electrospinning that orients the trajectory and collimates the electrified fluid jet of polymer nanofibers by induced electric fields.

Electrospinning is a process in which high voltage creates nanostructured fibers with random orientation from a polymer solution. A novel electrospinning instrument was designed and constructed, capable of orienting and collimating the trajectory of the electrified fluid jet. The equipment collimates and adjusts the electrified fluid jet in the X-Y directions using deflector plates connected to a variable electric field. Simultaneously, different membrane thicknesses can be selected, i.e., in the Z direction. Additionally, by programming the sinusoidal function generator to perform an X-Y sweep, Lissajous figures (LF) were obtained. SEM images obtained through XYZ electrospinning of PVC and PVDF membranes were used to determine the control achieved over the orientation distribution of the processed nanofibers and the modification of their diameter, with and without applying the electric field to the deflector plates. The nanofibers obtained from the polymeric membranes, which originated after the straight segment of the Taylor cone, did not exhibit a random trajectory and position. Instead, the collimated electrified fluid jet deposited them in a cross pattern (X-Y) on the collector-cathode plate.

The surface charge of electroactive materials governs cell behaviour through its effect on protein deposition.

The precise mechanisms underlying the cellular response to static electric cues remain unclear, limiting the design and development of biomaterials that utilize this parameter to enhance specific biological behaviours. To gather information on this matter we have explored the interaction of collagen type-I, the most abundant mammalian extracellular protein, with poly(vinylidene fluoride) (PVDF), an electroactive polymer with great potential for tissue engineering applications. Our results reveal significant differences in collagen affinity, conformation, and interaction strength depending on the electric charge of the PVDF surface, which subsequently affects the behaviour of mesenchymal stem cells seeded on them. These findings highlight the importance of surface charge in the establishment of the material-protein interface and ultimately in the biological response to the material. STATEMENT OF SIGNIFICANCE: The development of new tissue engineering strategies relies heavily on the understanding of how biomaterials interact with biological tissues. Although several factors drive this process and their driving principles have been identified, the relevance and mechanism by which the surface potential influences cell behaviour is still unknown. In our study, we investigate the interaction between collagen, the most abundant component of the extracellular matrix, and poly(vinylidene fluoride) with varying surface charges. Our findings reveal substantial variations in the binding forces, structure and adhesion of collagen on the different surfaces, which collectively explain the differential cellular responses. By exposing these differences, our research fills a critical knowledge gap and paves the way for innovations in material design for advanced tissue regeneration strategies.

Construction of CS-SDAEM long-chain polysaccharide derivative on TA@CNTs coated PVDF membrane with effective oil-water emulsion purification and low contamination rate.

Currently, the most effective way to improve the anti-fouling performance of water treatment separation membrane is to enhance the hydrophilicity of the membrane surface, but it can still cause contamination, leading to the occurrence of flux reduction. The construction of a strong hydration layer to resist wastewater contamination is still a challenging task. In this study, a defect-free hydration layer barrier was achieved by grafting chitosan polysaccharide derivatives (CS-SDAEM) on the membrane, which achieved in effective fouling prevention and low flux decline rate. A layer of tannic acid-coated carbon nanotubes (TA@CNTs) has been uniformly deposited on the commercial PVDF membrane so that the surface was rich in -COOH groups, providing sufficient reaction sites. These reactive groups facilitate the grafting of amphiphilic polymers onto the membrane. This modification strategy achieved in enhancing the antifouling performance. The modified membrane achieved low contamination rate with DR of 16.9 % for wastewater filtration, and the flux recovery rate was above 95 % with PWF of 1100 (L·m-2·h-1). The membrane had excellent anti-fouling performance, which provided a new route for the future development of water treatment membrane.

Thiol-Amino Bifunctional Metal-Organic-Framework-Based Membrane Regulating Hydrophobic Sites for Selective Separation of Artesunate.

The selective separation and purification of artesunate (ARU) and artemisinin (ART) using zirconium-based metal-organic frameworks (MOF), especially UiO-66 MOF, are receiving increasing attention. In this study, tunable "hydrophobic" sites of thiol (-SH) were introduced to amino-functionalized MOFs (UiO-66-NH2) to fabricate a thiol-amino bifunctional UiO-66/polyvinylidene fluoride (PVDF)-blended membrane (S1-UiO/PVDF-DPIM) via the delayed-phase-inversion method for selective separation of ARU/ART. The adsorption results indicated that the modification of UiO-66-NH2 with thiol can indeed increase the ARU adsorption. The thiol-functional MOF (S1-UiO-66-NH2) was chosen as the optimal thiol-amino bifunctional MOF, as it possessed the maximum ARU adsorption capacity (111.14 mg g-1) and the highest selective-separation factor (α = 51.84). The ATR FT-IR dynamic spectrum disclosed the recognition mechanism, indicating that incorporating thiol groups into a hydrophilic MOF as hydrophobic sites can boost adsorption efficiency. Moreover, the static-selective permeation results showed that the S1-UiO/PVDF-DPIM preferentially transfers ARU when mixed with ART, even achieving complete ARU/ART separation. The most crucial aspect was the introduction of a hydrophobic core of -SH and new spontaneously formed disulfide bonds to S1-UiO/PVDF-DPIM, creating alternated hydrogen bonds and hydrophobic interactions. This work provides an alternative strategy to prepare hydrophobic-hydrophilic MOF-based membranes for the highly efficient and selective separation of complex analogue systems.

On-site sensing for aflatoxicosis poisoning via ultraviolet excitable aptasensor based on fluorinated ethylene propylene strip: a promising forensic tool.

The environmental contamination by extremophile Aspergillus species, i.e., Aflatoxin B1, is hardly controllable in Southeast Asia and Sub-Saharan Africa, which lack handling resources and controlled storage facilities. Acute aflatoxicosis poisoning from aflatoxin-prone dietary staples could cause acute hepatic necrosis, acute liver failure, and death. Here, as the cheaper, more straightforward, and facile on-site diagnostic kit is needed, we report an ultraviolet-excitable optical aptasensor based on a fluorinated ethylene propylene film strip. Molecular dynamics on the aptamer.AFB1 complex revealed that the AFB1 to the aptamer increases the overall structural stability, suggesting that the aptamer design is suitable for the intended application. Under various influencing factors, the proposed label-free strategy offers a fast 20-min on-site fabrication simplicity and 19-day shelf-life. The one-pot incubation provides an alternative to catalytic detection and exhibited 4 times reusability. The recovery of crude brown sugar, processed peanuts, and long-grain rice were 102.74 ± 0.41 (n = 3), 86.90 ± 3.38 (n = 3), and 98.50 ± 0.42 (n = 3), comparable to High-Performance Liquid Chromatography-Photodiode Array Detector results. This study is novel owing to the peculiar UV-active spectrum fingerprint and the convenient use of hydrophobic film strips that could promote breakthrough innovations and new frontiers for on-site/forensic detection of environmental pollutants.

Construction of self-cleaning g-C3N4/Bi2MoO6/PVDF membrane and coupling with photo-Fenton-like reaction for sustainable removal of antibiotics in wastewater.

Constructing a photocatalytic membrane and photo-Fenton reaction coupling system is a novel strategy to enhance the photocatalytic activity of the membrane and eliminate the problem of membrane contamination. Herein, a g-C3N4/Bi2MoO6/PVDF photocatalytic membrane was prepared using a tannic acid-assisted in-situ deposition method. The membrane was characterized by three advantages of photocatalytic, self-cleaning, and antibacterial properties. Under the photo-Fenton-like conditions, the membrane had superior photodegradation efficiency of 90.7% for tetracycline, one of the main antibiotic contaminants in the China's aquatic system. Moreover, the membrane had excellent photo-Fenton self-cleaning ability, its flux recovery rate was up to 96%-98% after the self-cleaning process. Photoluminescence spectra, diffuse UV-visible spectrum, transient photocurrent responses, and electrochemical AC impedance spectrum results show that the heterojunction structure formed by g-C3N4 and Bi2MoO6 could improve the separation efficiency of photogenerated electrons-hole pairs. Electron spin resonance spectroscopy confirmed the photo-electrons facilitated the formation of hydroxyl radical (·OH) in the existence of H2O2, which enhanced tetracycline degradation. Moreover, the superior photo-Fenton self-cleaning performance, which mainly relied on the active free radicals produced by the photo-Fenton-like membrane to remove dirt on the membrane surface or in the membrane pore channel. Our results may shed new light on the development of promising photocatalytic membrane systems by coupling with photo-Fenton-like processes, and facilitate their applications for wastewater treatment.

Preparation of CoFe@C composite modified electrode for neohesperidin dihydrochalcone sensing and its application in Chinese medicine.

CoFe@C was first prepared by calcining the precursor of CoFe-metal-organic framework-74 (CoFe-MOF-74), then an electrochemical sensor for the determination of neohesperidin dihydrochalcone (NHDC) was constructed, which was stemmed from the novel CoFe@C/Nafion composite film modified glassy carbon electrode (GCE). The CoFe@C/Nafion composite was verified by field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). Electrochemical impedance spectroscopy (EIS) was used to evaluate its electrical properties as a modified material for an electrochemical sensor. Compared with CoFe-MOF-74 precursor modified electrode, CoFe@C/Nafion electrode exhibited a great synergic catalytic effect and extremely increased the oxidation peak signal of NHDC. The effects of various experimental conditions on the oxidation of NHDC were investigated and the calibration plot was tested. The results bespoken that CoFe@C/Nafion GCE has good reproducibility and anti-interference under the optimal experimental conditions. In addition, the differential pulse current response of NHDC was linear with its concentration within the range 0.08 ~ 20 µmol/L, and the linear regression coefficient was 0.9957. The detection limit was as low as 14.2 nmol/L (S/N = 3). In order to further verify the feasibility of the method, it was successfully used to determine the content of NHDC in Chinese medicine, with a satisfactory result, good in accordance with that of high performance liquid chromatography (HPLC).

Polydopamine bridging encapsulated laccase on MOF-based mixed-matrix membrane for selective dye/salt separation.

Mixed-matrix membranes (MMMs) exhibit significant potential for dye/salt separation. However, overcoming the "trade-off" between permeability and selectivity, as well as membrane fouling, remains a formidable task. In this work, a biocatalytic membrane was prepared using polydopamine (PDA) as a "bridge" connecting the metal-organic framework (MOF)-based MMM and immobilized laccase. The MOF-based MMM featured an interconnected MOF anchoring on the polyvinylidene fluoride (PVDF) skeleton structure, effectively mitigating the "trade-off" phenomenon and enabling efficient separation of dyes and salts. Enzyme-MOF was in situ grown on the MOF-based MMM via coordination reactions between PDA and metal ion, effectively degrading the adhesion of organic pollutants and fouling, ensuring the long-term stable operation of the membrane. The Lac-MOF@PDA MMM exhibited excellent water permeability of 142.4 L·m-2·h-1, 100 % rejection for dye, and less than 10 % rejection for NaCl. Furthermore, the separation mechanism of Lac-MOF@PDA MMM was systematically investigated, and the results suggested a synergistic combination of rejection, adsorption and catalysis processes. This biocatalytic membrane with multiple sieving and biological catalysis is expected to pave a promising way for efficient wastewater treatment applications.

High output flexible polyvinylidene fluoride based piezoelectric device incorporating cellulose nanofibers/BaTiO3@TiO2 piezoelectric core-shell structure.

Flexible composite film has gained increasing attention in the fields of wearable devices and portable electronic products. In this work, a novel core-shell structure of cellulose nanofibers/BaTiO3@TiO2 (CNF/BTO@TiO2) was synthesized with the assistant of the biological macromolecule material of cellulose nanofiber (CNF), in which the CNF can improve the stability and dispersibility of BaTiO3 (BTO) in the aqueous phase and elevate the integrity of the core-shell structure. The core-shell structure can reduce the agglomeration of fillers in polyvinylidene fluoride (PVDF) and improve the structural defects of the composite film. Meanwhile, the core-shell structure can promote the polarization of the electric dipole and the formation of ß phase in PVDF due to the generated interface spatial polarization between the shell of TiO2 and the core of BTO. When the content of the core-shell structure was 5 wt%, the ß phase content reaches 61.89 %, and the piezoelectric coefficient of composite film reaches 84.29 pm/V. Thus the maximum output open-circuit voltage (VOC) and short-circuit current (ISC) of the piezoelectric composite film is as high as 13.10 V and 464.3 nA. In addition, its excellent pressure sensing capability allows for its application in various flexible electronic devices.

PVDF-HFP encapsulated WS2nanosheets in droplet-based triboelectric nanogenerators for possible detection of human Na+/K+ion concentration.

Here we report the liquid-solid interaction in droplet-based triboelectric nanogenerators (TENG) for estimation of human Na+/K+levels. The exploitation of PVDF-HFP encapsulated WS2as active layer in the droplet-based TENG (DTENG) leads to the generation of electrical signal during the impact of water droplet. Comparison over the control devices indicates that surface quality and dielectric nature of the PVDF-HFP/WS2composite largely dictates the performance of the DTENG. The demonstration of excellent sensitivity of the DTENG towards water quality indicates its promising application towards water testing. In addition, the alteration in output signal with slightest variation in ionic concentration (Na+or K+) in water has been witnessed and is interpreted with charge transfer and ion transfer processes during liquid-solid interaction. The study reveals that the ion mobility largely affects the ion adsorption process on the active layer of PVDF-HFP/WS2and thus generates distinct output profiles for diverse ions like Na+and K+. Following that, the DTENG characteristics have been exploited to artificial urine where the varying output signals have been recorded for variation in urinary Na+ion concentration. Therefore, the deployment of PVDF-HFP/WS2in DTENG holds promising application towards the analyse of ionic characteristics of body fluids.

Performances of PTFE and PVDF membranes in achieving the discharge limit of mixed anodic oxidation coating wastewaters treated by membrane distillation.

The mixed wastewater generated by anodic oxidation coating facilities contains high levels of various contaminants, including iron, aluminum, conductivity, chemical oxygen demand (COD), and sulfate. In this study, the effectiveness of the membrane distillation (MD) process using polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) membranes was investigated to treat mixed wastewater from an anodized coating factory. The results indicate that both hydrophobic membranes effectively removed targeted contaminants. However, the PTFE membrane achieved higher removal efficiencies, with over 99% removal of sulfate, conductivity, iron, and aluminum, 85.7% of COD, and 86% of total organic carbon (TOC). In contrast, the PVDF membrane exhibited a significant decline in removal efficiency as the temperature increased and performed well only at lower feed temperatures. The PTFE membranes outperformed the PVDF membranes in treating chemically intensive anodic oxidation wastewaters. This superiority can be attributed to the PTFE membrane's morphology and structure, which are less influenced by feed water temperature and chemicals. Additionally, its slippery surface imparts anti-adhesion properties, effectively preventing membrane fouling, and maintaining the treated water quality and flux for longer operation time.

Anodic stripping voltammetry of arsenic determination with edible mushroom-nafion-modified glassy carbon electrode.

An edible Mushroom-Nafion modified glassy carbon electrode (M2N5-GCE) was prepared using a homogeneous mixture varying the concentrations of these, in addition to the origin of the mushroom (Shiitake, Lentinula edodes, M1 and Abrantes, Agariscus bisporus, M2) and applied to the As(III) determination by anodic stripping voltammetry. After choosing the optimal conditions in the preparation of the electrode, the second stage was to study the effects of various parameters such as supporting electrolyte, pH, accumulation potential, and time (Eacc, tacc). The optimum experimental conditions chosen were Britton Robinson buffer 0.01 mol L-1 pH:4.6; Eacc: -1.0 and tacc: 60 s obtaining a signal of oxidation of As(0) to As(III) about 0.08 V. Peak current was proportional to arsenic concentration over the 19.6-117.6 µg L-1 range, with a 3σ detection limit of 13.4 µg L-1. The method was validated using As(III) spiked tap water from the laboratory with satisfactory results (RE:3.0 %). Finally, the method was applied to the determination of As(III) in water samples from the Loa River (Northern Chile) in the presence of As(V) in a concentration >20 times higher (RE: 2.3 %).

[The results of clinical application of the mesh with anti-adhesive fluoropolymer coating in laparoscopic intraperitoneal repair of primary ventral hernia]. / Rezul'taty klinicheskogo primeneniya setchatogo endoproteza s antiadgezivnym ftorpolimernym pokrytiem pri laparoskopicheskoi intraperitoneal'noi plastike pervichnykh ventral'nykh gryzh.

OBJECTIVE: The purpose of the study was to evaluate the results of using fluoropolymer-coated mesh during intraperitoneal onlay mesh hernia repair in patients with primary ventral hernias. MATERIAL AND METHODS: The multicenter, non-randomized, controlled clinical study included 88 patients of both sexes who were operated on using a laparoscopic approach using the IPOM technique for a primary ventral hernia. The duration of observation ranged from 3 to 12 months. In the main group, 48 patients received fluoropolymer-coated meshes (Ftorex). A comparison was made with a retrospective group of 40 patients who were treated with anti-adhesive collagen-coated meshes (Parietene composite, Parietex Composite, Symbotex). RESULTS: The number of early and late postoperative complications in the groups did not have significant differences, at the same time, their number was lower in the group of patients in whom fluoropolymer-coated meshes were used. Most of the complications corresponded to Clavien-Dindo class I and II and did not pose a significant threat to health. There were no recurrences of hernias observed in patients included in the study. There were slightly more adhesions in the fluoropolymer-coated mesh group (35.4% vs. 25.0% in the collagen-coated mesh group). The quality of life of patients in the study groups did not differ. CONCLUSION: In laparoscopic IPOM hernia repair fluoropolymer-coated meshes are not inferior in effectiveness and safety to traditionally used collagen-coated meshes and can be recommended for use in patients with primary ventral hernias.

Synergetic Improvement of Flexoelectric Coefficient in Liquid Crystal Embedded Flexible PVDF Polymer Composite for Energy Harvesting Applications.

Flexoelectricity is the universal electric polarization of dielectrics upon exertion of a non-uniform strain gradient. With the advancement of nano-technology and miniaturization of electronic devices, flexoelectricity holds the promise to address the power requirements for such device operation. The direct flexoelectric effect in liquid crystal (LC) embedded poly(vinylidene fluoride) (PVDF) polymer films is examined for the first time by the application of external strain on the films. Physical characterizations such as Differential Scanning Calorimetry (DSC), dielectric spectroscopy, X-ray diffraction, and field emission scanning electron microscopy (FESEM) are carried out to study the composite films' intrinsic and extrinsic properties like dielectric, crystallinity, and morphologies. The value of the flexoelectric coefficient (µ12) increases with the concentration of LC incorporation. At 3 wt%, µ12 attains a maximum value of 68 nC m-1, which is more than a threefold increase compared to that of the pure PVDF film. The role of Maxwell-Wagner-Sillars (MWS) polarization in determining flexoelectric polarization in polymer composites is also discussed. Moreover, the influence of the microstructure and domain size formation in determining the flexoelectric response are discussed in detail to infer the behavior of the flexoelectric coefficients of the films. Potential device applications based on this phenomenon have been proposed for future research in sensing and actuation.

Evaluation of various membranes at different fluxes to enable large-volume single-use perfusion bioreactors.

The growing demand for biological therapeutics has increased interest in large-volume perfusion bioreactors, but the operation and scalability of perfusion membranes remain a challenge. This study evaluates perfusion cell culture performance and monoclonal antibody (mAb) productivity at various membrane fluxes (1.5-5 LMH), utilizing polyvinylidene difluoride (PVDF), polyethersulfone (PES), or polysulfone (PS) membranes in tangential flow filtration mode. At low flux, culture with PVDF membrane maintained higher cell culture growth, permeate titer (1.06-1.34 g/L) and sieving coefficients (≥83%) but showed lower permeate volumetric throughput and higher transmembrane pressure (TMP) (>1.50 psi) in the later part of the run compared to cultures with PES and PS membrane. However, as permeate flux increased, the total mass of product decreased by around 30% for cultures with PVDF membrane, while it remained consistent with PES and PS membrane, and at the highest flux studied, PES membrane generated 12% more product than PVDF membrane. This highlights that membrane selection for large-volume perfusion bioreactors depends on the productivity and permeate flux required. Since operating large-volume perfusion bioreactors at low flux would require several cell retention devices and a complex setup, PVDF membranes are suitable for low-volume operations at low fluxes whereas PES membranes can be a desirable alternative for large-volume higher demand products at higher fluxes.

Highly effective ultrafiltration membranes based on plastic waste for dye removal from water.

Applicable and low-cost ultrafiltration membranes based on waste polystyrene (WPS) blend and poly vinylidene fluoride (PVDF) were effectively cast on nonwoven support using phase inversion method. Analysis was done into how the WPS ratio affected the morphology and antifouling performance of the fabricated membranes. Cross flow filtration of pure water and various types of polluted aqueous solutions as the feed was used to assess the performance of the membranes. The morphology analysis shows that the WPS/PVDF membrane layer has completely changed from a spongy structure to a finger-like structure. In addition, the modified membrane with 50% WPS demonstrated that the trade-off between selectivity and permeability is met by a significant improvement in the rejection of the membrane with a reduction in permeate flux due to the addition of PVDF. With a water permeability of 50 LMH and 44 LMH, respectively, the optimized WPS-PVDF membrane with 50% WPS could reject 81% and 74% of Congo red dye (CR) and methylene blue dye (MB), respectively. The flux recovery ratio (FRR) reached to 88.2% by increasing PVDF concentration with 50% wt. Also, this membrane has the lowest irreversible fouling (Rir) value of 11.7% and lowest reversible fouling (Rr) value of 27.9%. The percent of cleaning efficiency reach to 71%, 90%, and 85% after eight cycles of humic acid (HA), CR, and MB filtration, respectively, for the modified PS-PVDF (50%-50%). However, higher PVDF values cause the membrane's pores to become clogged, increase the irreversible fouling, and decrease the cleaning efficiency. In addition to providing promising filtration results, the modified membrane is inexpensive because it was made from waste polystyrene, and as a result, it could be scaled up to treat colored wastewater produced by textile industries. PRACTITIONER POINTS: Recycling of plastic waste as an UF membrane for water/wastewater treatment was successfully prepared and investigated. Mechanical properties showed reasonable response with adding PVDF. The modified membrane with 50% PS demonstrated that the trade-off between selectivity and permeability is met by a significant improvement in the rejection.

A Comparative Study and Prediction of the Ex Vivo Permeation of Six Vaginally Administered Drugs across Five Artificial Membranes and Vaginal Tissue.

The theoretical interpretation of the vaginal permeability phenomenon, the evaluation of the suitability of five artificial membranes, and the prediction of the behaviors of vaginal drugs were the main objectives of this study. Franz vertical diffusion cells and different validated HPLC methods were used to measure the permeability of six vaginally administered drugs (econazole, miconazole, metronidazole, clindamycin, lidocaine, and nonoxynol-9). This study was performed (in vitro) on different membranes of polyvinylidene fluoride (PVDF), plain cellulose or cellulose impregnated with isopropyl myristate (IPM), and cellulose combined with PVDF or IPM. The results were compared with those obtained from cow vaginal tissue (ex vivo), where cellulose was proven to be the best simulant. According to the permeability profiles (Papp), the water solubility of the drugs was considered a necessary criterion for their transport in the membranes or in the tissue, while the size was important for their penetration. Furthermore, it was found that polar compounds show clear superiority when penetrating cellulose or tissue, while non-polar ones show superiority when penetrating the lipophilic PVDF membrane. Finally, a successful attempt was made to predict the Papp values (|Papp-predPapp| < 0.005) of the six drugs under study based on a PLS (Partial Least Squares) in silico simulation model.

Enhancing proton transport in polyvinylidenedifluoride membranes and reducing biofouling for improved hydrogen production in microbial electrolysis cells.

Hydrophilic porous membranes, exemplified by polyvinylidene fluoride (PVDF) membranes, have demonstrated significant potential for replacing ion exchange membranes in microbial electrolysis cells (MECs). Membrane fouling remains a major challenge in MECs, impeding proton transport and consequently limiting hydrogen production. This study aims to investigate a synergistic antifouling strategy for PVDF membrane through the incorporation of a coating composed of polydopamine (PDA), polyethyleneimine (PEI), and silver nanoparticles (AgNPs). The PDA-PEI-Ag@PVDF membrane not only effectively mitigates fouling through steric and electrostatic repulsion forces, but also amplifies ion transport by facilitating water diffusion and electromigration. The PDA-PEI-Ag@PVDF membrane exhibited a reduced membrane resistance of 1.01 mΩ m2 and PDA-PEI-Ag modifying PVDF membrane was found to be effective in enhancing the proton transportation of PVDF membrane. Therefore, the enhanced hydrogen production rate of 2.65 ± 0.02 m3/m3/d was achieved in PDA-PEI-Ag@PVDF-MECs.