Lipid exchange of apolipoprotein A-I amyloidogenic variants in reconstituted high-density lipoprotein with artificial membranes.

High-density lipoproteins (HDLs) are responsible for removing cholesterol from arterial walls, through a process known as reverse cholesterol transport. The main protein in HDL, apolipoprotein A-I (ApoA-I), is essential to this process, and changes in its sequence significantly alter HDL structure and functions. ApoA-I amyloidogenic variants, associated with a particular hereditary degenerative disease, are particularly effective at facilitating cholesterol removal, thus protecting carriers from cardiovascular disease. Thus, it is conceivable that reconstituted HDL (rHDL) formulations containing ApoA-I proteins with functional/structural features similar to those of amyloidogenic variants hold potential as a promising therapeutic approach. Here we explored the effect of protein cargo and lipid composition on the function of rHDL containing one of the ApoA-I amyloidogenic variants G26R or L174S by Fourier transformed infrared spectroscopy and neutron reflectometry. Moreover, small-angle x-ray scattering uncovered the structural and functional differences between rHDL particles, which could help to comprehend higher cholesterol efflux activity and apparent lower phospholipid (PL) affinity. Our findings indicate distinct trends in lipid exchange (removal vs. deposition) capacities of various rHDL particles, with the rHDL containing the ApoA-I amyloidogenic variants showing a markedly lower ability to remove lipids from artificial membranes compared to the rHDL containing the native protein. This effect strongly depends on the level of PL unsaturation and on the particles' ultrastructure. The study highlights the importance of the protein cargo, along with lipid composition, in shaping rHDL structure, contributing to our understanding of lipid-protein interactions and their behavior.

Reversible pH-Gated MXene Membranes with Ultrahigh Mono-/Divalent-Ion Selectivity.

Artificial ion channel membranes hold high promise in water treatment, nanofluidics, and energy conversion, but it remains a great challenge to construct such smart membranes with both reversible ion-gating capability and desirable ion selectivity. Herein, we constructed a smart MXene-based membrane via p-phenylenediamine functionalization (MLM-PPD) with highly stable and aligned two-dimensional subnanochannels, which exhibits reversible ion-gating capability and ultrahigh metal ion selectivity similar to biological ion channels. The pH-sensitive groups within the MLM-PPD channel confers excellent reversible Mg2+-gating capability with a pH-switching ratio of up to 100. The mono/divalent metal-ion selectivity up to 1243.8 and 400.9 for K+/Mg2+ and Li+/Mg2+, respectively, outperforms other reported membranes. Theoretical calculations combined with experimental results reveal that the steric hindrance and stronger PPD-ion interactions substantially enhance the energy barrier for divalent metal ions passing through the MLM-PPD, and thus leading to ultrahigh mono/divalent metal-ion selectivity. This work provides a new strategy for developing artificial-ion channel membranes with both reversible ion-gating functionality and high-ion selectivity for various applications.

Further treatment of coking wastewater treated in A2O-MBR by the nanofiltration-powder activated carbon hybrid system.

In this study, further treatment of coking wastewater treated in anoxic-oxic-membrane bioreactor (A2O-MBR) was investigated to meet the standards of the ministry by means of nanofiltration (NF) (with two different membranes and different pressures), microfiltration -powder activated carbon (MF-PAC) hybrid system and NF-PAC (with two different membranes and five different PAC concentrations) hybrid system. In addition to the parameters determined by the ministry, other parameters such as ammonium, thiocyanate (SCN-), hydrogen cyanide (HCN), dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), color were also examined to evaluate the flux performance and treatment efficiency of the hybrid processes. According to the results, chemical oxygen demand (COD) in the NF process, COD and total cyanide (T-CN) in the MF-PAC process could not meet the discharge standards. As for the NF-PAC hybrid system, XN45 membrane met the discharge standards in all parameters (COD = 96±1.88 mg/L, T-CN =<0,02 mg/L, phenol =<0.05 mg/L), with a recovery rate of 78% at 0.5 g/L PAC concentration.

Simultaneous electrocoagulation and E-peroxone coupled with ultrafiltration membrane for shale gas produced water treatment.

Membrane fouling caused by the organics-coated particles was the main obstacle for the highly efficient shale gas produced water (SGPW) treatment and recycling. In this study, a novel hybrid electrocoagulation (EC) and E-peroxone process coupled with UF (ECP-UF) process was proposed to examine the efficacy and elucidate the mechanism for UF fouling mitigation in assisting SGPW reuse. Compared to the TMP (transmembrane pressure) increase of -15 kPa in the EC-UF process, TMP in ECP-UF system marginally increased to -1.4 kPa for 3 filtration cycles under the current density of 15 mA/cm2. Both the total fouling index and hydraulically irreversible fouling index of the ECP-UF process were significantly lower than those of EC-UF process. According to the extended Derjaguin-Landau-Verwey-Overbeek theory, the potential barriers was the highest for ECP-UF processes due to the substantial increase of the acid-base interaction energy in ECP-UF process, which was well consistent with the TMP and SEM results. Turbidity and TOC of ECP-UF process were 63.6% and 45.8% lower than those of EC-UF process, respectively. According to the MW distribution, the variations of compounds and their relative contents were probably due to the oxidation and decomposing products of the macromolecular organics. The number of aromatic compound decreased, while the number of open-chain compounds (i.e., alkenes, alkanes and alcohols) increased in the permeate of ECP-UF process. Notably, the substantial decrease in the relative abundance of di-phthalate compounds was attributed to the high reactivity of these compounds with ·OH. Mechanism study indicated that ECP could realize the simultaneous coagulation, H2O2 generation and activation by O3, facilitating the enhancement of ·OH and Alb production and therefore beneficial for the improved water quality and UF fouling mitigation. Therefore, the ECP-UF process emerges as a high-efficient and space-saving approach, yielding a synergistic effect in mitigating UF fouling for SGPW recycling.

Effects of low-flux and high-flux hemodialysis on the survival of elderly maintenance hemodialysis patients.

BACKGROUND: Elderly hemodialysis (HD) patients have a high risk of death. The effect of different types of HD membranes on survival is still controversial. The purpose of this study was to determine the relationship between the use of low-flux or high-flux membranes and all-cause and cardiovascular mortality in elderly hemodialysis patients. METHODS: This was a retrospective clinical study involving maintenance hemodialysis patients which were categorized into low-flux and high-flux groups according to the dialyzer they were using. Propensity score matching was used to balance the baseline data of the two groups. Survival rates were compared between the two groups, and the risk factors for death were analyzed by multivariate Cox regression. RESULTS: Kaplan-Meier survival analysis revealed no significant difference in all-cause mortality between the low-flux group and the high-flux group (log-rank test, p = 0.559). Cardiovascular mortality was significantly greater in the low-flux group than in the high-flux group (log-rank test, p = 0.049). After adjustment through three different multivariate models, we detected no significant difference in all-cause mortality. Patients in the high-flux group had a lower risk of cardiovascular death than did those in the low-flux group (HR = 0.79, 95% CI, 0.54-1.16, p = 0.222; HR = 0.58, 95% CI, 0.37-0.91, p = 0.019). CONCLUSIONS: High-flux hemodialysis was associated with a lower relative risk of cardiovascular mortality in elderly MHD patients. High-flux hemodialysis did not improve all-cause mortality rate. Differences in urea distribution volume, blood flow, and systemic differences in solute clearance by dialyzers were not further analyzed, which are the limitations of this study.

Differential scanning calorimetry in drug-membrane interactions.

Differential Scanning Calorimetry (DSC) is a central technique in investigating drug - membrane interactions, a critical component of pharmaceutical research. DSC measures the heat difference between a sample of interest and a reference as a function of temperature or time, contributing essential knowledge on the thermally induced phase changes in lipid membranes and how these changes are affected by incorporating pharmacological substances. The manuscript discusses the use of phospholipid bilayers, which can form structures like unilamellar and multilamellar vesicles, providing a simplified yet representative membrane model to investigate the complex dynamics of how drugs interact with and penetrate cellular barriers. The manuscript consolidates data from various studies, providing a comprehensive understanding of the mechanisms underlying drug - membrane interactions, the determinants that influence these interactions, and the crucial role of DSC in elucidating these components. It further explores the interactions of specific classes of drugs with phospholipid membranes, including non-steroidal anti-inflammatory drugs, anticancer agents, natural products with antioxidant properties, and Alzheimer's disease therapeutics. The manuscript underscores the critical importance of DSC in this field and the need for continued research to improve our understanding of these interactions, acting as a valuable resource for researchers.

Compact and water flushing resistant mesh biofilms forming at short SRT disappeared naturally under extended SRT in dynamic membrane bioreactor.

Extending the solids retention time (SRT) has been demonstrated to mitigate membrane biofouling. Nevertheless, it remains an intriguing question whether the compact and water flushing resistant mesh biofilms developed at short SRT can undergo biodegradation and be removed with extended SRT. In present study, the bio-fouled mesh filter in the 10d-SRT dynamic membrane bioreactor (DMBR), with mesh surfaces and pores covered by compact and water flushing resistant biofilms exhibiting low water permeability, was reused in the 40d-SRT DMBR without any cleanings. After being reused at 40d-SRT, its flux driven by gravity occurred from the 10th day and recovered to a regular level of 36.7 L m-2·h-1 on the 27th day. Both scanning electron microscope (SEM) and confocal laser scanning microscopy (CLSM) analyses indicated that the compact mesh biofilms formed at10d-SRT biodegraded and were removed at 40d-SRT, with the residual biofilms becoming removable by water flushing. As a result, the hydraulic resistance of the bio-fouled mesh filter decreased from 4.36 × 108 to 6.97 × 107 m-1, and its flux fully recovered. The protein and polysaccharides densities in mesh-biofilms decreased from 24.4 to 9.7 mg/cm2 and from 10.7 to 0.10 mg/cm2, respectively, which probably have contributed to the disappearance of compact biofilms and the decrease in adhesion. Furthermore, the sludge and mesh-biofilms in the 40d-SRT reactor contained a higher relative abundance of dominant quorum quenching bacteria, such as Rhizobium (3.52% and 1.35%), compared to those in the 10d-SRT sludge (0.096%) and mesh biofilms (0.79%), which might have been linked to a decline in extracellular polymeric substances and, consequently, the biodegradation and disappearance of compact biofilms.

Photocatalytic Zinc Oxide Nanoparticles in Antibacterial Ultrafiltration Membranes for Biofouling Control.

Global water scarcity is a threat that can be alleviated through membrane filtration technologies. However, the widespread adoption of membranes faces significant challenges, primarily due to membrane biofouling. This is the reason why membrane modifications have been under increasing investigation to address the fouling issues. Antibacterial membranes, designed to combat biofouling by eliminating microorganisms, offer a promising solution. Within this study, flat sheet ultrafiltration (UF) membranes with integrated photocatalytic zinc oxide (ZnO) nanoparticles were developed, characterized, and assessed through filtration and fouling tests. The antibacterial properties of the membranes were conducted in static tests using Gram-negative bacteria-Escherichia coli-and natural tap water biofilm. The results demonstrated a notable enhancement in membrane surface wettability and fouling resistance. Furthermore, the incorporation of ZnO resulted in substantial photocatalytic antibacterial activity, inactivating over 99.9% of cultivable E. coli. The antibacterial activity persisted even in the absence of light. At the same time, the persistence of natural tap water organisms in biofilms of modified membranes necessitates further in-depth research on complex biofilm interactions with such membranes.

Synergistic effects of biochar addition and filtration mode optimization on mitigating membrane fouling in high-solid anaerobic membrane bioreactors.

In this study, a high-solid anaerobic membrane bioreactor was established for treating food waste, and membrane fouling rates were regulated through multivariate modulation. The anaerobic membrane bioreactor operated stably at a high organic loading rate of 28.75 gCOD/L/d achieved a methane production rate of 8.03 ± 0.61 L/L/d. Experimental findings revealed that the most effective control of membrane fouling was achieved at a filtration- relaxation ratio (F/R) of 10/90 s. This indicates that a higher relaxation frequency provided improved the mitigation of membrane fouling. Compared with single F/R modulation, the combined modulation of biochar and F/R provided enhanced control over membrane fouling. Moreover, the addition of biochar altered the sludge properties of the reactor, thereby preventing the formation of a dense cake layer. Additionally, biochar enhanced the sheer force of the fluid on the membrane surface and facilitated the separation of pollutants during the relaxation stage, thereby contributing to improved control of membrane fouling.

A Hollow Microneedle Equipped with a Micropillar for Improved Needle Insertion and Injection of Drug Solution.

PURPOSE: Hollow-type microneedles (hMNs) are a promising device for the effective administration of drugs into intradermal sites. Complete insertion of the needle into the skin and administration of the drug solution without leakage must be achieved to obtain bioavailability or a constant effect. In the present study, several types of hMN with or without a rounded blunt tip micropillar, which suppresses skin deformation, around a hollow needle, and the effect on successful needle insertion and administration of a drug solution was investigated. Six different types of hMNs with needle lengths of 1000, 1300, and 1500 µm with or without a micropillar were used. METHODS: Needle insertion and the disposition of a drug in rat skin were investigated. In addition, the displacement-force profile during application of hMNs was also investigated using a texture analyzer with an artificial membrane to examine needle factors affecting successful insertion and administration of a drug solution by comparing with in vivo results. RESULTS: According to the results with the drug distribution of iodine, hMN1300 with a micropillar was able to successfully inject drug solution into an intradermal site with a high success rate. In addition, the results of displacement-force profiles with an artificial membrane showed that a micropillar can be effective for depth control of the injected solution as well as the prevention of contact between the hMN pedestal and the deformed membrane. CONCLUSION: In the present study, hMN1300S showed effective solution delivery into an intradermal site. In particular, a micropillar can be effective for depth control of the injected solution as well as preventing contact between the hMN pedestal and the deformed membrane. The obtained results will help in the design and development of hMNs that ensure successful injection of an administered drug.

Understanding Rejection Mechanisms of Trace Organic Contaminants by Polyamide Membranes via Data-Knowledge Codriven Machine Learning.

Data-driven machine learning (ML) provides a promising approach to understanding and predicting the rejection of trace organic contaminants (TrOCs) by polyamide (PA). However, various confounding variables, coupled with data scarcity, restrict the direct application of data-driven ML. In this study, we developed a data-knowledge codriven ML model via domain-knowledge embedding and explored its application in comprehending TrOC rejection by PA membranes. Domain-knowledge embedding enhanced both the predictive performance and the interpretability of the ML model. The contribution of key mechanisms, including size exclusion, charge effect, hydrophobic interaction, etc., that dominate the rejections of the three TrOC categories (neutral hydrophilic, neutral hydrophobic, and charged TrOCs) was quantified. Log D and molecular charge emerge as key factors contributing to the discernible variations in the rejection among the three TrOC categories. Furthermore, we quantitatively compared the TrOC rejection mechanisms between nanofiltration (NF) and reverse osmosis (RO) PA membranes. The charge effect and hydrophobic interactions possessed higher weights for NF to reject TrOCs, while the size exclusion in RO played a more important role. This study demonstrated the effectiveness of the data-knowledge codriven ML method in understanding TrOC rejection by PA membranes, providing a methodology to formulate a strategy for targeted TrOC removal.

Excessive Ozonation Stress Triggers Severe Membrane Biofilm Accumulation and Fouling.

The established benefits of ozone on microbial pathogen inactivation, natural organic matter degradation, and inorganic/organic contaminant oxidation have favored its application in drinking water treatment. However, viable bacteria are still present after the ozonation of raw water, bringing a potential risk to membrane filtration systems in terms of biofilm accumulation and fouling. In this study, we shed light on the role of the specific ozone dose (0.5 mg-O3/mg-C) in biofilm accumulation during long-term membrane ultrafiltration. Results demonstrated that ozonation transformed the molecular structure of influent dissolved organic matter (DOM), producing fractions that were highly bioavailable at a specific ozone dose of 0.5, which was inferred to be a turning point. With the increase of the specific ozone dose, the biofilm microbial consortium was substantially shifted, demonstrating a decrease in richness and diversity. Unexpectedly, the opportunistic pathogen Legionella was stimulated and occurred in approximately 40% relative abundance at the higher specific ozone dose of 1. Accordingly, the membrane filtration system with a specific ozone dose of 0.5 presented a lower biofilm thickness, a weaker fluorescence intensity, smaller concentrations of polysaccharides and proteins, and a lower Raman activity, leading to a lower hydraulic resistance, compared to that with a specific ozone dose of 1. Our findings highlight the interaction mechanism between molecular-level DOM composition, biofilm microbial consortium, and membrane filtration performance, which provides an in-depth understanding of the impact of ozonation on biofilm accumulation.

Hypercrosslinked Hydrogel Composite Membranes Targeted for Removal of Volatile Organic Compounds via Selective Solution-Diffusion in Membrane Distillation.

Membrane distillation (MD) has attracted considerable interest in hypersaline wastewater treatment. However, its practicability is severely impeded by the ineffective interception of volatile organic compounds (VOCs), which seriously affects the product water quality. Herein, a hypercrosslinked alginate (Alg)/aluminum (Al) hydrogel composite membrane is facilely fabricated via Alg pregel formation and ionic crosslinking for efficient VOC interception. The obtained MD membrane shows a sufficient phenol rejection of 99.52% at the phenol concentration of 100 ppm, which is the highest rejection among the reported MD membranes. Moreover, the hydrogel composite membrane maintains a high phenol interception (>99%), regardless of the feed temperature, initial phenol concentration, and operating time. Diffusion experiments and molecular dynamics simulation verify that the selective diffusion is the dominant mechanism for VOCs-water separation. Phenol experiences a higher energy barrier to pass through the dense hydrogel layer compared to water molecules as the stronger interaction between phenol-Alg compared with water-Alg. Benefited from the dense and hydratable Alg/Al hydrogel layer, the composite membrane also exhibits robust resistance to wetting and fouling during long-term operation. The superior VOCs removal efficiency and excellent durability endow the hydrogel composite membrane with a promising application for treating complex wastewater containing both volatile and nonvolatile contaminants.

Solvent-free parallel artificial liquid membrane extraction for drugs of abuse in plasma samples using LC-MS/MS.

BACKGROUND: Parallel artificial liquid membrane extraction (PALME) is a 96-well plate setup variant of liquid-phase microextraction. Basic or acidic analytes are extracted in neutral form from the sample, through a supported liquid membrane (SLM), and into aqueous acceptor. PALME is already considered a green extraction technique, but in the current conceptual work, we sought to make it even greener by replacing the use of organic solvents with essential oils (EO). PALME was combined with LC-MS/MS for analysis of plasma samples and multiple drugs of abuse with toxicological relevance (amphetamines, phenethylamines, synthetic cathinones, designer benzodiazepines, ayahuasca alkaloids, lysergic acid diethylamide, and ketamine). RESULTS: Fourteen EO were compared to organic solvents frequently used in PALME. The EO termed smart & sassy yielded the best analyte recovery for all drugs studied and was thus selected as SLM. Then, factorial screening and Box-Behnken were employed to optimize the technique. The extraction time, concentration of base, sample volume, and percentage of trioctylamine significantly impacted analyte recovery. The optimum values were defined as 120 min, 10 mmol/L of NaOH, 150 µL, and 0%, respectively. Once optimized, validation parameters were 1-100 ng mL-1 as linear range, accuracy ±16.4%, precision >83%, 1 ng mL-1 as limit of quantitation, 0.1-0.75 ng mL-1 as limit of detection, matrix effect <20%, and recovery 20-106%. Additionally, EO purchased from different production batches were tested and achieved acceptable reproducibility. Data were in compliance with requirements set by internationally accepted validation guidelines and the applicability of the technique was proven using authentic samples. SIGNIFICANCE: In this study, the use of an EO provided a solvent-free sample preparation technique suited to extract different classes of drugs of abuse from plasma samples, dismissing the use of hazardous organic solvents. The method also provided excellent sample clean-up, thus being a simple and efficient tool for toxicological applications that is in agreement with the principles of sustainable chemistry.

Anaerobic acidification membrane bioreactor operating at acidic condition for treating concentrated municipal wastewater: Performance and implication.

To address the low-carbon treatment requirements for municipal wastewater, a novel anaerobic acidification membrane bioreactor (AAMBR) was developed for recovering organic matter in terms of volatile fatty acids (VFAs). While the AAMBR successfully generated VFAs from municipal wastewater through forward osmosis (FO) membrane concentration, its operation was limited to a single pH value of 10.0. Here, performance of the AAMBR operating at acidic condition was evaluated and compared with that at alkaline condition. The findings revealed that the AAMBR with pH 5.0 efficiently transformed organic matter into acetic acid, propionic acid, and butyric acid, resulting in a VFAs yield of 0.48 g/g-CODfeed. In comparison with the AAMBR at pH 10.0, this study achieved a similar VFAs yield, a lower fouling tendency, a lower loss of nutrients and a lower controlling cost. In conclusion, this study demonstrated that a pH of 5.0 is optimal for the AAMBR treating municipal wastewater.

[Comparative study on the degradation rate and regulatory effects of two resorbable collagen membranes during the in vivo implantation].

Objective: To explore the differences in the performance and tissue repair promotion effects of small intestinal submucosa membrane (SIS membrane) and Bio-Gide resorbable collagen membrane (Bio-Gide membrane) by performing the subcutaneous implantation models in mice. Methods: For in vivo studies, we stablished membrane implantation models using 6-8 week-old male C57BL/6 mice. The degradation rates were explored through HE staining analysis at different time points (1, 3, 5, 7, 14 and 28 d, 3 mice/group/time point). The influences of the two membranes on local macrophages and neovasculum were evaluated by immunofluorescence detection of F4/80 and CD31, and the mobilization effects of the two membranes on local stem cells were evaluated by immunohistochemical detection of Ki67 and CD146. For in vitro studies, mice periodontal ligament stem cells (mPDLSCs) were co-cultured with these two membrane materials, and the cell morphologies were observed by scanning electron microscopy. In addition, the gene expressions of Ki67, Cxcl1, Ccl1, Tnfa were investigated by real-time fluorescence quantitative PCR (RT-qPCR). Results: The results of in vivo studies showed that by day 28, there was no significant difference in degradation rate between these two membrane materials [SIS degradation rate: (16.84±4.00) %, Bio-Gide degradation rate: (24.07±3.97) %, P=0.090], illustrating that both of them could maintain the barrier effects for more than one month. In addition, there was no significant difference in the infiltration number of local F4/80 positive macrophages between these two groups by the day 3 after implantation [SIS: (20.67±5.69) cells/visual field, Bio-Gide: (25.33±2.52) cells/visual field, P=0.292]. However, compared with the Bio-Gide membrane, SIS membrane significantly promoted local CD31+vascular regeneration [SIS: (4.67±1.15) cells/visual field, Bio-Gide: (1.00±1.00) cells/visual field, P=0.015] and CD146+stem cell recruitment [SIS: (22.33±4.16) cells/visual field, Bio-Gide: (11.33±2.52) cells/visual field, P=0.025]. The RT-qPCR results also showed that SIS membrane promoted the gene expression of Cxcl1 (SIS vs Bio-Gide P<0.001) in mPDLSCs, but had no effect on the gene expression of Tnfa (SIS vs Bio-Gide P=0.885). Conclusions: SIS membrane showed a similar degradation rate compared with Bio-Gide membrane, and there was no significant difference in the effects of these two membranes on local inflammation or macrophages. Therefore, both of these membranes could meet the barrier effects required by guided tissue regeneration.

Parafilm® M and Strat-M® as skin simulants in in vitro permeation of dissolving microarray patches loaded with proteins.

In vitro permeation studies play a crucial role in early formulation optimisation before extensive animal model investigations. Biological membranes are typically used in these studies to mimic human skin conditions accurately. However, when focusing on protein and peptide transdermal delivery, utilising biological membranes can complicate analysis and quantification processes. This study aims to explore Parafilm®M and Strat-M® as alternatives to dermatomed porcine skin for evaluating protein delivery from dissolving microarray patch (MAP) platforms. Initially, various MAPs loaded with different model proteins (ovalbumin, bovine serum albumin and amniotic mesenchymal stem cell metabolite products) were prepared. These dissolving MAPs underwent evaluation for insertion properties and in vitro permeation profiles when combined with different membranes, dermatomed porcine skin, Parafilm®M, and Strat-M®. Insertion profiles indicated that both Parafilm®M and Strat-M® showed comparable insertion depths to dermatomed porcine skin (in range of 360-430 µm), suggesting promise as membrane substitutes for insertion studies. In in vitro permeation studies, synthetic membranes such as Parafilm®M and Strat-M® demonstrated the ability to bypass protein-derived skin interference, providing more reliable results compared to dermatomed neonatal porcine skin. Consequently, these findings present valuable tools for preliminary screening across various MAP formulations, especially in the transdermal delivery of proteins and peptides.

Large-Scale Fabrication of Freestanding Polymer Ultrathin Porous Membranes for Transparent Transwell Coculture Systems.

Advancements in cell coculture systems with porous membranes have facilitated the simulation of human-like in vitro microenvironments for diverse biomedical applications. However, conventional Transwell membranes face limitations in low porosity (ca. 6%) and optical opacity due to their large thickness (ca. 10 µm). In this study, we demonstrated a one-step, large-scale fabrication of freestanding polymer ultrathin porous (PUP) membranes with thicknesses of hundreds of nanometers. PUP membranes were produced by using a gap-controlled bar-coating process combined with polymer blend phase separation. They are 20 times thinner than Transwell membranes, possessing 3-fold higher porosity and exhibiting high transparency. These membranes demonstrate outstanding molecular permeability and significantly reduce the cell-cell distance, thereby facilitating efficient signal exchange pathways between cells. This research enables the establishment of a cutting-edge in vitro cell coculture system, enhancing optical transparency, and streamlining the large-scale manufacturing of porous membranes.

Polyamide Membranes with Tunable Surface Charge Induced by Dipole-Dipole Interaction for Selective Ion Separation.

Nanofiltration (NF) has the potential to achieve precise ion-ion separation at the subnanometer scale, which is necessary for resource recovery and a circular water economy. Fabricating NF membranes for selective ion separation is highly desirable but represents a substantial technical challenge. Dipole-dipole interaction is a mechanism of intermolecular attractions between polar molecules with a dipole moment due to uneven charge distribution, but such an interaction has not been leveraged to tune membrane structure and selectivity. Herein, we propose a novel strategy to achieve tunable surface charge of polyamide membrane by introducing polar solvent with a large dipole moment during interfacial polymerization, in which the dipole-dipole interaction with acyl chloride groups of trimesoyl chloride (TMC) can successfully intervene in the amidation reaction to alter the density of surface carboxyl groups in the polyamide selective layer. As a result, the prepared positively charged (PEI-TMC)-NH2 and negatively charged (PEI-TMC)-COOH composite membranes, which show similarly high water permeance, demonstrate highly selective separations of cations and anions in engineering applications, respectively. Our findings, for the first time, confirm that solvent-induced dipole-dipole interactions are able to alter the charge type and density of polyamide membranes and achieve tunable surface charge for selective and efficient ion separation.

Evaluation of Regenerative Efficacy of Amnion and Chorion Membrane in Treatment of Mandibular Molar Furcation Defects: A Clinico-radiographic Study.

AIM: Amnion and chorion membranes possess unique inherited biological properties that enhance wound healing and may accelerate periodontal regeneration. The present study aims to evaluate and compare the efficacy of amnion and chorion membranes in the treatment of furcation defects. MATERIALS AND METHODS: A total of 20 patients were selected and were randomly allocated to group I and group II with 10 subjects in each group. Amnion and chorion membranes are placental-derived membranes that accelerate regeneration by having natural growth factors with their antimicrobial and inflammation reduction properties. Group I was treated using bone grafting with decalcified freeze-dried bone allograft (DFDBA) and placement of amnion as a membrane for guided tissue regeneration (GTR) whereas group II was treated using bone grafting with DFDBA and placement of chorion as a membrane for GTR. The patients were followed for clinical and radiographic parameters and were evaluated between 3 and 6 months after surgery. RESULT: In intragroup comparison, a significant difference was evident in both the groups for all the clinical and radiographic parameters within the groups. (p = 0.01) This means both amnion and chorion membranes showed statistically significant regenerative efficacy. In intergroup comparison, the results show that all the clinical parameters and radiographic parameters show no significant difference between the groups. CONCLUSION: The amnion and chorion membranes had similar regenerative efficacy in combination with DFDBA in patients with buccal degree II furcation defects in mandibular molars. CLINICAL SIGNIFICANCE: The amnion and chorion membranes have shown significant improvement in clinical and radiographic parameters when used for the treatment of buccal degree II furcation defects in mandibular molars. How to cite this article: Mallapragda S, Gupta R, Gupta S, et al. Evaluation of Regenerative Efficacy of Amnion and Chorion Membrane in Treatment of Mandibular Molar Furcation Defects: A Clinico-radiographic Study. J Contemp Dent Pract 2024;25(2):160-167.