Cross-linking Step Research Articles

Organic Solvent Nanofiltration Membrane with In Situ Constructed Covalent Organic Frameworks as Separation Layer

Organic solvent nanofiltration (OSN) technology is advantageous for separating mixtures of organic solutions owing to its low energy consumption and environmental friendliness. Covalent organic frameworks (COFs) are good candidates for enhancing the efficiency of solvent transport and ensuring precise molecular sieving of OSN membranes. In this study, p-phenylenediamine (Pa) and 1,3,5-trimethoxybenzene (Tp) are used to construct, in situ, a TpPa COF skin layer via interfacial polymerization (IP) on a polyimide substrate surface. After subsequent crosslinking and activation steps, a kind of TpPa/polyimide (PI) OSN membrane is obtained. Under optimized fabrications, this OSN membrane exhibits an ethanol permeance of 58.0 LMH/MPa, a fast green FCF (FGF) rejection of 96.2%, as well as a pure n-hexane permeance of 102.0 LMH/MPa. Furthermore, the TpPa/PI OSN membrane exhibits good solvent resistance, which makes it suitable for the separation, purification, and concentration of organic solvents.

Experimental and Modelling Study of Controlled Release from Dextran-Based Cryogels.

In this work, five different dextran-based cryogels for controlled drug release are investigated. Vitamin B12 was used as a model drug for in vitro release tests. Two different drug-loading procedures were adopted, leading to very different drug release curves. Indeed, a fast Fickian release was observed when freeze-dried samples of DEX40PEG360MA and DEX40PEG500MA were infused with the drug after cryogel formation. On the contrary, a slowed highly non-Fickian behavior arises when the drug is loaded before the low-temperature crosslinking step, leading to the cryogel formation. The non-Fickian drug release, observed for all the five different dextran-based cryogels investigated, is actually due to the cryoconcentration phenomenon, modeled with a two-step release process. The proposed transport model accurately predicts experimental release curves characterized by a long lag time, confirming that dextran-based cryogels are suitable for controlled release.

Loss of the long form of Plod2 phenocopies contractures of Bruck syndrome-osteogenesis imperfecta.

Bruck syndrome is an autosomal recessive form of osteogenesis imperfecta caused by biallelic variants in PLOD2 or FKBP10 and is characterized by joint contractures, bone fragility, short stature, and scoliosis. PLOD2 encodes LH2, which hydroxylates type I collagen telopeptide lysines, a critical step for collagen crosslinking. The Plod2 global knockout mouse model is limited by early embryonic lethality, and thus, the role of PLOD2 in skeletogenesis is not well understood. We generated a novel Plod2 mouse line modeling a variant identified in two unrelated individuals with Bruck syndrome: PLOD2 c.1559dupC, predicting a frameshift and loss of the long isoform LH2b. In the mouse, the duplication led to loss of LH2b mRNA as well as significantly reduced total LH2 protein. This model, Plod2fs/fs, survived up to E18.5 although in non-Mendelian genotype frequencies. The homozygous frameshift model recapitulated the joint contractures seen in Bruck syndrome and had indications of absent type I collagen telopeptide lysine hydroxylation in bone. Genetically labeling tendons with Scleraxis-GFP in Plod2fs/fs mice revealed the loss of extensor tendons in the forelimb by E18.5, and developmental studies showed extensor tendons developed through E14.5 but were absent starting at E16.5. Second harmonic generation showed abnormal tendon type I collagen fiber organization, suggesting structurally abnormal tendons. Characterization of the skeleton by μCT and Raman spectroscopy showed normal bone mineralization levels. This work highlights the importance of properly crosslinked type I collagen in tendon and bone, providing a promising new mouse model to further our understanding of Bruck syndrome.

Rapid and Efficient Isolation of Total RNA-Bound Proteomes by Liquid Emulsion-Assisted Purification of RNA-Bound Protein (LEAP-RBP).

The critical roles of RNA-binding proteins (RBPs) in all aspects of RNA biology fostered the development of methods utilizing ultraviolet (UV) crosslinking and method-specific RNA enrichment steps for proteome-wide identification and assessment of RBP function. Despite the substantial contributions of these UV-based RNA-centric methods to our understanding of RNA-protein interaction networks, their utility is constrained by biases in RBP recovery and significant noise contributions, which can confound meaningful interpretation. To overcome these issues, we recently developed a method termed Liquid Emulsion-Assisted Purification of RNA-Bound Protein (LEAP-RBP) and introduced quantitative signal-to-noise (S:N)-based metrics for the proteome-wide identification of RNA interactomes and accurate assessment of global RBP occupancy dynamics. Compared to existing methodologies, LEAP-RBP provides significant advantages in speed, cost, efficiency, and selectivity for RNA-bound proteins. In this work, we provide a step-by-step guide for the successful application of the LEAP-RBP method for both small- and large-scale investigations of RNA-bound proteomes. Key features • Unbiased and efficient isolation of total RNA-bound protein, RNA, and protein from biological samples. • Cost-effective identification of proteome-wide RNA interactomes and validation of direct RNA-binding protein functionality. • Robust and accurate assessment of context- and/or condition-dependent RBP occupancy state dynamics.

Droplet Microfluidic Method for Estimating the Dynamic Interfacial Tension of Ion-Crosslinked Sodium Alginate Microspheres.

The research focuses on optimizing the production of hydrogel microspheres using droplet microfluidics for pharmaceutical and bioengineering applications. A semiempirical method has been developed to predict the dynamic interfacial tension at the interface of ion-cross-linked sodium alginate microsphere-sunflower oil modified with glacial acetic acid and Tween 80 surfactant. These microspheres are produced in a small-scale coaxial device that is manufactured using affordable DLP/LCD 3D printing technology with a transparent photopolymer. The method was tested to design the minireactor in the device, which allows for the production of fully cross-linked microspheres that are ready for use at the output of the reactor without additional cross-linking steps in the microsphere collector. The mathematical expression for estimating the interfacial tension at the moment of formation of a hydrogel microsphere includes the Reynolds number for a two-phase liquid, the Ohnesorge number, and the surface tension at the liquid-air interface for continuous medium flow (modified oil). The reliability of the prediction is confirmed for continuous medium and dispersed phase flow rates of 0.8-3.2 and 0.01-0.08 mL/min, respectively. The evolution of the interfacial tension from the moment the microspheres formed and the estimated ultimate interfacial tension in a cross-linked hydrogel-modified oil system contributed to the reliable determination of the linear size of a minireactor. The ultimate interfacial tension of 76.5 ± 0.3 mN/m was determined using the Young-Laplace equation, which is based on measuring the surface free energy of the hydrogel as soft matter using the Owens-Wendt method. Additionally, the equilibrium static contact angle of the fully cross-linked hydrogel surface wetted with oil is measured using the sessile drop method. From a practical perspective, a method for optimizing and streamlining the high-tech manufacturing of cross-linked polymer microspheres and mini- and microchannel devices for use in bioengineering and pharmaceutical applications is suggested.

Single-Step 3D Bioprinting of Alginate-Collagen Type I Hydrogel Fiber Rings to Promote Angiogenic Network Formation.

In the advent of tissue engineering and regenerative medicine, the demand for innovative approaches to biofabricate complex vascular structures is increasing. We describe a single-step 3D bioprinting method leveraging Aspect Biosystems RX1 technology, which integrates the crosslinking step at a flow-focusing junction, to biofabricate immortalized adult rat brain endothelial cell (SV-ARBEC)-encapsulated alginate-collagen type I hydrogel rings. This single-step biofabrication process involves the strategic layer-by-layer assembly of hydrogel rings, encapsulating SV-ARBECs in a spatially controlled manner while optimizing access to media and nutrients. The spatial arrangement of the SV-ARBECs within the rings promotes spontaneous angiogenic network formation and the constrained deposition of cells within the hydrogel matrix facilitates tissue-like organized vascular-like network development. This approach provides a platform that can be adapted to many different endothelial cell types and leveraged to better understand the mechanisms driving angiogenesis and vascular-network formation in 3D bioprinted constructs supporting the development of more complex tissue and disease models for advancing drug discovery, tissue engineering, and regenerative medicine applications.

ZrC/SiC composites from functionalised ZrC combining preceramic precursors and SPS

ZrC/SiC composites were obtained in situ using Spark Plasma Sintering (SPS), with a previous organic functionalisation of ZrC particles (ZrCf). It used the direct ceramisation/sintering of ZrCf/polycarbosilane mixture without any previous crosslinking steps. The prior functionalisation did not have an effect on either the relative density of the materials or the mechanical properties. However, larger SiC domains were observed around the functionalised ZrC particles, probably due to the hydrosilylation reaction between pendant alkene groups and Si-H from the commercial polycarbosilane. In addition, TEM analyses showed different features such as the presence of inter- and intra-granular SiC, and of a double layer at the grain boundaries between the ZrC and SiC phases, when avoiding functionalisation. The oxidation behaviour was also tested, and the prior functionalisation improved the properties of the final samples.

Enhanced adsorption capacity of phosphoric acid-modified montmorillonite clay and ground coffee waste-derived carbon-based functional composite beads for the effective removal of methylene blue

Clays, valued for their versatility, serve as economical adsorbents. Recent studies show that physical, thermal, and chemical modifications can enhance their adsorption capacity. In this study, the synthesis of a functional bead comprising phosphoric acid-modified montmorillonite (PMMT) and coffee waste carbon (CWC) and its application for the efficient adsorption of methylene blue (MeB) dye is investigated. A highly flexible and low-cost phyllosilicate, montmorillonite clay, MMT was treated with phosphoric acid to enhance the ionic density, composited with CWC, resulting in improved surface properties thereafter was transformed into easily recoverable bead form through subsequent cross-linking steps. These functional composite beads were characterized using various characterization techniques. As a result, the existing tetrahedral sheets possessed by the MMT having weak bonds between the layers are improved in a way that they can allow molecule exchange for the efficient enhancement of the adsorption capacity of the composite material. Moreover, after the necessary modifications, the adsorbent was found to be mechanically stable, inhibiting secondary pollutions from the use in powder forms while allowing the interlayers favorable for not just cationic but also anionic exchange whilst increasing the specific surface area and pore volume. The surface area was enhanced to 9.93 m2 /g. Following this, maximum adsorption capacity of 489.9 mg/g was attained showing a superior removal efficiency for methylene blue dye (>80%). The adsorption equilibrium was analyzed using Freundlich and Langmuir models. The adsorption mechanism aligns with the Langmuir model which encompasses a monolayer adsorption. All in all, this study is anticipated to play a crucial role in the search for adsorbents with multiple functionalities and good structural stability during and after use.

The encapsulation and controlled release of proteins from “meltable” chemically cross‐linked hydrogels

AbstractChemically crosslinked hydrogels can be used for the controlled delivery of therapeutic proteins, however, cargo loading can be challenging. A common approach involves performing the hydrogel crosslinking step in the presence of the cargo proteins, however, this can require the utilization of selective chemistries to ensure the cargos do not chemically react with the forming hydrogel network. We demonstrate that chemically crosslinked hydrogels based upon the protein polymer Capsular antigen fragment 1 (Caf1) can be used to encapsulate proteins within a chemically crosslinked hydrogel network. This encapsulation exploits the “meltable” feature of Caf1 hydrogels, where upon heating the Caf1 protein unfolds with concomitant depolymerization of the hydrogel network. Protein cargos can be loaded into the “molten” form of the hydrogel which cools with protein refolding and concomitant reformation of the hydrogel network to entrap the cargos, ensuring a more homogenous dispersion of the cargo. Analysis of release profiles indicated lower burst release in comparison to release from identical hydrogels loaded by an absorption method. This work is significant because it suggest that the “meltable” feature of Caf1 hydrogels may present an improved method of loading protein cargos into crosslinked hydrogel networks whilst avoiding the need for crosslinking chemistries.

XL-DNase-Seq: Footprinting Analysis of Dynamic Transcription Factors.

We have developed a novel method for genomic footprinting of transcription factors (TFs) that detects potential gene regulatory relationships from DNase-seq data at the nucleotide level. We introduce an assay termed cross-link (XL)-DNase-seq, designed to capture chromatin interactions of dynamic TFs. A mild cross-linking step in XL-DNase-seq improves the detection of DNase-based footprints of dynamic TFs. The footprint strengths and detectability depend on an optimal cross-linking procedure. This method may help extract novel gene regulatory circuits involving previously undetectable TFs. The XL-DNase-seq method is illustrated here for activated mouse macrophage-like cells, which share several features with inflammatory macrophages.

Characterization of Maltogenic Amylase Activity Recovery: A Potential Approach for Improving Immobilization

Cross-linked enzymes aggregate (CLEA) is a versatile carrier free-immobilization technique that has gained much attention in the development of biocatalyst technology. However, there is no precise and accurate method of using this technique that will lead to an expected outcome that meets the requirements of the industrial standard. Therefore, the objective of this study is to investigate the effect of a few methods of executing cross-linked enzyme aggregates approach using maltogenic amylase by measuring the activity recovery of the developed CLEA. Some factors that are considered in developing the methodologies are the interaction between cross-linkers and enzymes, size of the cross-linked enzyme aggregates and substrate diffusion. The addition of precipitant and the cross-linking agent steps has been manipulated and four different methodologies were developed. Based on the results, Method 2 showed the highest activity recovery (57.9%) whilst Method 4 gave the lowest activity recovery (15.7%). Method 2 is an improvised method that removed supernatant after centrifugation before proceeding to the cross-linking step. The characterization of cross-linked enzyme aggregates such as morphological characterization and Fourier Transform-Infrared Spectroscopy was also determined. In conclusion, the best and most productive preparation method was determined based on the highest activity recovery.

Removal of heavy metals from wastewater by aerogel derived from date palm waste

Cellulose that has been sourced from date palm leaves as a primary component was utilised. This cellulose served as the foundational material for the development of an aerogel composite. During this process, MXene (Ti3C2Tx) played a pivotal role in enhancing the overall composition of the aerogel. To ensure the stability and durability of the resulting aerogel structure, calcium ions were introduced to the mix. These ions facilitated the cross-linking process of sodium alginate molecules, ultimately leading to the formation of calcium alginate. This cross-linking step is crucial for the enhanced mechanical and chemical stability of the aerogel. Incorporating alginate and Ti3C2Tx into the cellulose aerogel enhanced its structural integrity in aqueous conditions and increased its adsorption capacity. When evaluated with synthetic wastewater, this composite exhibited remarkable adsorption capacities of 72.9, 114.4, 92.9, and 123.9 mg/g for As, Cd, Ni, and Zn ions, respectively. A systematic study was carried out to see the effect of various parameters, including contact time, MXene concentration, pH, and temperature on the adsorption of these elements. Peak adsorption was achieved at 60 min, favoring a pH range between 6 and 8 and exhibited optimal sorption efficiency at lower temperatures. The adsorption kinetics adhered closely to a pseudo-second-order, while the Freundlich model adeptly described the adsorption isotherms. An interesting result of this research was the aerogel's regenerative potential. After undergoing a basic acid treatment, the MXene/cellulose/alginate aerogel composite could be restored and reused for up to three cycles, all while maintaining its core performance capabilities even after the rigorous cross-linking processes. In three consecutive cycles, the removal percentages for As, Cd, Ni, and Zn were 48.15%, 80.38%, 56.51%, and 86.12% in cycle 1; 37.35%, 65.63%, 45.97%, and 78.42% in cycle 2; and 28.60%, 56.22%, 34.70%, and 65.83% in cycle 3, respectively. The composite was tested in conditions resembling seawater salinity. Impressively, the aerogel continued to demonstrate a significant ability to adsorb metals, reinforcing its potential utility in real-world aquatic scenarios. These findings suggest that the composite aerogel, integrating MXene, cellulose, and alginate, is an effective medium for the targeted removal of heavy metals from aquatic environments.

Processing-microstructure correlations in material extrusion additive manufacturing of carbon fiber reinforced ceramic matrix composites

Liquid silicon infiltration is a cost-effective manufacturing route for carbon fiber reinforced silicon carbide (C/C-SiC)11C/C-SiC: carbon fiber reinforced silicon carbide, which is a ceramic matrix composite with high specific stiffness associated with damage tolerance. To reduce the cost-intensive machining while improving the geometric freedom of design, a processing route for C/C-SiC based on material extrusion additive manufacturing was investigated. Filament-based material extrusion was applied to manufacture green bodies made of short carbon fiber reinforced polyetheretherketone (PEEK)22PEEK: polyetheretherketone. Additionally, a thermo-oxidative crosslinking step, which is assumed to be a function of the specific surface area, was introduced prior to pyrolysis to prevent the re-melting of PEEK. Via computer-aided image analysis, the influence of process parameters during material extrusion on the green bodies’ specific surface area were investigated using statistical design of experiments. It was shown that it is possible to selectively adjust the specific surface area by modifying the microstructure of the carbon fiber reinforced green bodies and hence the shrinkage during pyrolysis, the liquid silicon infiltration kinetics as well as the phase composition of the obtained C/C-SiC. The understanding of the processing-microstructure correlations enabled an improvement of the mechanical properties. With a layer height of 0.1 mm, an infill density of 100% and a printing direction of ± 45°, a flexural strength of 80.3 ± 6.7 MPa was measured.

Self-Assembly of Structured Colloidal Gels for High-Resolution 3D Micropatterning of Proteins at Scale.

Self-assembly, the spontaneous ordering of components into patterns, is widespread in nature and fundamental to generating function across length scales. Morphogen gradients in biological development are paradigmatic as both products and effectors of self-assembly and various attempts have been made to reproduce such gradients in biomaterial design. To date, approaches have typically utilized top-down fabrication techniques that, while allowing high-resolution control, are limited by scale and require chemical cross-linking steps to stabilize morphogen patterns in time. Here, a bottom-up approach to protein patterning is developed based on a novel binary reaction-diffusion process where proteins function as diffusive reactants to assemble a nanoclay-protein composite hydrogel. Using this approach, it is possible to generate scalable and highly stable 3D patterns of target proteins down to sub-cellular resolution through only physical interactions between clay nanoparticles and the proteins and ions present in blood. Patterned nanoclay gels are able to guide cell behavior to precisely template bone tissue formation in vivo. These results demonstrate the feasibility of stabilizing 3D gradients of biological signals through self-assembly processes and open up new possibilities for morphogen-based therapeutic strategies and models of biological development and repair.

Immunolabel-First-Expand-Later Expansion Microscopy Approach Using Stable STED Dyes.

Multiple expansion microscopy approaches have been successfully used in the analysis of centrioles, centrosomes, and cilia, helping to reveal the localization of numerous centrosomal and ciliary proteins at nanoscale resolution. In this chapter, we describe the use of two stable STED dyes in combination with expansion microscopy, which allows the robust detection by conventional and STED microscopy of proteins immunolabeled prior to sample expansion. We demonstrate the stability of these dyes during the crosslinking, polymerization, and denaturation steps of an expansion protocol thereby allowing their use in an immunolabel-first-expand-later approach. Our protocol overcomes the frequent technical limitation of poor, unreproducible binding of primary antibodies to proteins after denaturation. We demonstrate the applicability of this approach by analyzing both a centriole appendage protein Cep164 and a ciliary protein ARL13B.

Lignin/Poly(vinylpyrrolidone) Multifilament Fibers Dry‐Spun from Water as Carbon Fiber Precursors

AbstractThe preparation of lignin‐based carbon fibers by dry spinning from aqueous solution followed by stabilization and continuous carbonization to endless yarns is reported. The influence of carbonization temperature and draw ratio on the morphology and mechanical properties of the final carbon fibers is investigated by single‐fiber testing, wide‐angle X‐ray scattering, scanning electron microscopy, and Raman spectroscopy. A draw ratio of 5% (1.05) with a carbonization temperature of 1400 °C leads to the best mechanical properties. The resulting multifilament carbon fibers have an average diameter between 10–12 µm, an average tensile strength of 1.30 ± 0.32 GPa, a Young's modulus of 101 ± 18 GPa, and an elongation at break of 1.31 ± 0.23%. The maximum Weibull strength (𝜎0) is 1.04 GPa with a Weibull modulus (m) of 5.1. The use of a water‐soluble system is economically advantageous; also, unlike melt‐spun lignin fibers, the dry‐spun precursor fibers can be thermally converted without any additional crosslinking step.

Porous Poly(2-hydroxyethyl methacrylate) Hydrogel Scaffolds for Tissue Engineering: Influence of Crosslinking Systems and Silk Sericin Concentration on Scaffold Properties.

Tailored porous structures of poly(2-hydroxyethyl methacrylate) (PHEMA) and silk sericin (SS) were used to create porous hydrogel scaffolds using two distinct crosslinking systems. These structures were designed to closely mimic the porous nature of the native extracellular matrix. Conventional free radical polymerization of 2-hydroxyethyl methacrylate (HEMA) was performed in the presence of different concentrations of SS (1.25, 2.50, 5.00% w/v) with two crosslinking systems. A chemical crosslinking system with N'N-methylene bisacrylamide (MBAAm) and a physical crosslinking system with dimethylurea (DMU) were used: C-PHEMA/SS (crosslinked using MBAAm) and C-PHEMA/pC-SS (crosslinked using MBAAm and DMU). The focus of this study was on investigating the impact of these crosslinking methods on various properties of the scaffolds, including pore size, pore characteristics, polymerization time, morphology, molecular interaction, in vitro degradation, thermal properties, and in vitro cytotoxicity. The various crosslinked networks were found to appreciably influence the properties of the scaffolds, especially the pore sizes, in which smaller sizes and higher numbers of pores with high regularity were seen in C-PHEMA/1.25 pC-SS (17 ± 2 μm) than in C-PHEMA/1.25 SS (34 ± 3 μm). Semi-interpenetrating networks were created by crosslinking PHEMA-MBAAm-PHEMA while incorporating free protein molecules of SS within the networks. The additional crosslinking step involving DMU occurred through hydrogen bonding of the -C=O and -N-H groups with the SS, resulting in the simultaneous incorporation of DMU and SS within the PHEMA networks. As a consequence of this process, the scaffold C-PHEMA/pC-SS exhibited smaller pore sizes compared to scaffolds without DMU crosslinking. Moreover, the incorporation of higher loadings of SS led to even smaller pore sizes. Additionally, the gelation time of C-PHEMA/pC-SS was delayed due to the presence of DMU in the crosslinking system. Both porous hydrogel scaffolds, C-PHEMA/pC-SS and PHEMA, were found to be non-cytotoxic to the normal human skin dermal fibroblast cell line (NHDF cells). This promising result indicates that these hydrogel scaffolds have potential for use in tissue engineering applications.

Electrical Conduction and Space Charge in Gamma-Irradiated XLPE

It is well known that ionizing radiation impact dielectric and mechanical properties of polymers, as a result of chain scission, crosslinking, and oxidation steps. The electrical conductivity is generally substantially increased after irradiation. We analyze such effects in XLPE after gamma-irradiation. Current measurements reveal a substantial increase in conductivity after irradiation at doses up to 200 kGy. Current-field characteristics change after irradiation and appear indicative of an ionic-type conduction. Space charge measurements confirm the mechanism with obvious heterocharge build-up after irradiation.

Easy and Versatile Technique for the Preparation of Stable and Active Lipase-Based CLEA-like Copolymers by Using Two Homofunctional Cross-Linking Agents: Application to the Preparation of Enantiopure Ibuprofen.

An easy and versatile method was designed and applied successfully to obtain access to lipase-based cross-linked-enzyme aggregate-like copolymers (CLEA-LCs) using one-pot, consecutive cross-linking steps using two types of homobifunctional cross-linkers (glutaraldehyde and putrescine), mediated with amine activation through pH alteration (pH jump) as a key step in the process. Six lipases were utilised in order to assess the effectiveness of the technique, in terms of immobilization yields, hydrolytic activities, thermal stability and application in kinetic resolution. A good retention of catalytic properties was found for all cases, together with an important thermal and storage stability improvement. Particularly, the CLEA-LCs derived from Candida rugosa lipase showed an outstanding behaviour in terms of thermostability and capability for catalysing the enantioselective hydrolysis of racemic ibuprofen ethyl ester, furnishing the eutomer (S)-ibuprofen with very high conversion and enantioselectivity.

Recent Advances in the Support Layer, Interlayer and Active Layer of TFC and TFN Organic Solvent Nanofiltration (OSN) Membranes: A Review.

Although separation of solutes from organic solutions is considered a challenging process, it is inevitable in various chemical, petrochemical and pharmaceutical industries. OSN membranes are the heart of OSN technology that are widely utilized to separate various solutes and contaminants from organic solvents, which is now considered an emerging field. Hence, numerous studies have been attracted to this field to manufacture novel membranes with outstanding properties. Thin-film composite (TFC) and nanocomposite (TFN) membranes are two different classes of membranes that have been recently utilized for this purpose. TFC and TFN membranes are made up of similar layers, and the difference is the use of various nanoparticles in TFN membranes, which are classified into two types of porous and nonporous ones, for enhancing the permeate flux. This study aims to review recent advances in TFC and TFN membranes fabricated for organic solvent nanofiltration (OSN) applications. Here, we will first study the materials used to fabricate the support layer, not only the membranes which are not stable in organic solvents and require to be cross-linked, but also those which are inherently stable in harsh media and do not need any cross-linking step, and all of their advantages and disadvantages. Then, we will study the effects of fabricating different interlayers on the performance of the membranes, and the mechanisms of introducing an interlayer in the regulation of the PA structure. At the final step, we will study the type of monomers utilized for the fabrication of the active layer, the effect of surfactants in reducing the tension between the monomers and the membrane surface, and the type of nanoparticles used in the active layer of TFN membranes and their effects in enhancing the membrane separation performance.