Hydrophilic Support Research Articles

High performance polyacrylonitrile-supported forward osmosis membranes prepared via aromatic solvent-based interfacial polymerization

A high performance thin film composite (TFC) forward osmosis (FO) membrane was prepared using a hydrophilic polyacrylonitrile (PAN) support with a tailored structure via a newly devised, aromatic solvent (toluene)-based interfacial polymerization (TIP) technique. The use of toluene as the organic solvent promoted amine diffusion toward the organic phase and the subsequent reaction, leading to the formation of an ultrathin (highly permeable) and highly dense (highly selective) polyamide selective layer on the PAN support, which improved membrane performance. In addition, a relatively thin (∼80 μm) and finger-like porous support structure embedded with a nonwoven fabric was favorable for facilitating mass transport in the support. As a result, the TFC FO membrane prepared via TIP showed ∼2.1 times higher FO water flux and ∼68% lower specific salt flux than the membrane prepared via conventional aliphatic solvent-based interfacial polymerization (IP) in FO mode. Importantly, our TIP-assembled membrane exhibited superior FO performance over commercial and other lab-made membranes. Our strategy provides a facile solution to overcome the technical limitations of the conventional IP method by enabling the fabrication of high performance PA layers on hydrophilic supports, expanding the application spectrum of TFC membranes.

User-Tailored Metal-Organic Frameworks as Supports for Carbonic Anhydrase.

Carbonic anhydrase (CA) was previously proposed as a green alternative for biomineralization of carbon dioxide (CO2). However, enzyme's fragile nature when in synthetic environment significantly limits such industrial application. Herein, we hypothesized that CA immobilization onto flexible and hydrated "bridges" that ensure proton-transfer at their interfaces leads to improved activity and kinetic behavior and potentially increases enzyme's feasibility for industrial implementation. Our hypothesis was formulated considering that water plays a key role in the CO2 hydration process and acts as both the reactant as well as the rate-limiting step of the CO2 capture and transformation process. To demonstrate our hypothesis, two types of user-synthesized organic metallic frameworks [metal-organic frameworks (MOFs), one hydrophilic and one hydrophobic] were considered as model supports and their surface characteristics (i.e., charge, shape, curvature, size, etc.) and influence on the immobilized enzyme's behavior were evaluated. Morphology, crystallinity and particle size, and surface area of the model supports were determined by scanning electron microscopy, dynamic light scattering, and nitrogen adsorption/desorption measurements, respectively. Enzyme activity, kinetics, and stability at the supports interfaces were determined using spectroscopical analyses. Analysis showed that enzyme functionality is dependent on the support used in the immobilization process, with the enzyme immobilized onto the hydrophilic support retaining 72% activity of the free CA, when compared with that immobilized onto the hydrophobic one that only retained about 28% activity. Both CA-MOF conjugates showed good storage stability relative to the free enzyme in solution, with CA immobilized at the hydrophilic support also revealing increased thermal stability and retention of almost all original enzyme activity even after heating treatment at 70 °C. In contrast, free CA lost almost half of its original activity when subject to the same conditions. This present work suggests that MOFs tunable hydration conditions allow high enzyme activity and stability retention. Such results are expected to impact CO2 storage and transformation strategies based on CA and potentially increase user-integration of enzyme-based green technologies in mitigating global warming.

Photocatalytic Nanoparticulate ZrxTi1‐xO2 Coatings with Controlled Homogeneity of Elemental Composition

AbstractThe mixed oxide ZrxTi1‐xO2 nanoparticulate photocatalysts of different compositions (0≤x≤1) were prepared via sol‐gel method in a rapid micromixing reactor followed by chemical colloid deposition on borosilicate glass beads, drying and heat treatment at temperatures between 400 to 650 °C. The point‐like reaction conditions in the regime of low Damköhler numbers resulted in nucleation of size‐selected reactive zirconium‐titanium oxo‐alkoxy (ZTOA) nanoparticles from zirconium (IV) propoxide and titanium (IV) isopropoxide precursors, which enable strong covalent bonds with hydrophilic supports. The ZTOA nanoparticles with compositions 0≤x≤0.2 convert after a heat treatment to nanoporous monocrystals in distorted anatase phase. The photocatalytic activity of the prepared nanoparticulate coatings on gaseous ethylene decomposition attained maximum at x=0.043 after heat treatment at 500 °C, which was two times higher than that of pure anatase TiO2. A net correlation between the material photocatalytic activity and amplitude of the slow power decay of photoinduced charges was observed. A model is proposed explaining the power law decay by a thermal release of the localised charges from shallow surface Urbach states. The number density of these states is connected to the specific surface area of the photocatalyst.

Advanced porous membranes with slit-like selective layer for flow battery

An advanced porous membrane containing slit-like selective layer on its top surface is designed and prepared for flow battery application. The structure is realized by regulating the parameters during membrane formation process. The porous membrane exhibits a thick skin layer with narrow slits and sponge-like support layer in the cross-section. The thick and comparatively hydrophobic skin layer hinders the passage of vanadium ions. Meanwhile, the slit structure and comparatively hydrophilic support layer facilitates the transport of protons. The resulting poly(ether sulfone) (PES)/sulfonated poly(ether ether ketone) (SPEEK) porous membrane containing slit-like selective layer achieves an excellent balance between ion selectivity and proton conductivity, resulting in a columbic efficiency of 98.5%, a voltage efficiency of 91.7%, and an energy efficiency of 90.4% at 80 mA cm−2, which is much higher than a vanadium flow battery (VFB) with the commercial Nafion 115. Therefore, this paper provides a simple and economical method to develop high-performance, low-cost membranes for VFB applications.

Thin-Film Nanocomposite Forward-Osmosis Membranes on Hydrophilic Microfiltration Support with an Intermediate Layer of Graphene Oxide and Multiwall Carbon Nanotube.

A novel thin-film nanocomposite forward-osmosis (FO) membrane was fabricated on hydrophilic nylon microfiltration (MF) support by interfacial polymerization with the assistance of an intermediate layer of graphene oxide and multiwall carbon nanotube (GO/MWCNT). The chemical composition, structure, and surface properties of the synthesized FO membranes were studied using various characterization methods. It was found that the GO/MWCNT composite layer not only provided ultrafast nanochannels for water transport but also reduced the thickness of the polyamide layer by up to 60%. As a result, the novel FO membrane exhibited a higher water flux and lower reverse salt flux compared with the membrane synthesized without the GO/MWCNT intermediate layer. This method offers promising opportunities to fabricate thin-film composite membranes on microfiltration substrates for FO application with inhibited concentration polarization phenomenon and expected separation performance.

Activated carbon enhanced hydrophobic/hydrophilic dual-layer nanofiber composite membranes for high-performance direct contact membrane distillation

In this study, activated carbon (AC) enhanced hydrophobic/hydrophilic dual-layer nanofiber composite membranes were prepared for direct contact membrane distillation (DCMD) by incorporating different concentrations (0–3.0 wt%) of AC nanoparticles into the polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) hydrophobic active layer. The membranes were composed of two layers, a thin hydrophobic PVDF-HFP/AC electrospun active layer and a thick hydrophilic support layer. Results indicated that the incorporation of AC nanoparticles have greatly increased the membrane properties and performance. The membrane containing 1.5 wt% AC nanoparticles (M3) showed the best flux performance (45.6 L/m2 h) compared to other membranes fabricated in this study and a commercial PTFE benchmark membrane (41.8 L/m2 h) without compromising the salt rejection. A two-dimensional model was developed to investigate the flux profile of the PVDF-HFP/AC membranes. The present study suggests that the incorporation of AC nanoparticles into PVDF-HFP active layer can impart additional functionalities to the composite membranes that would enhance the membranes DCMD performance. The fabricated PVDF-HFP/AC composite membranes present great potential in the application of DCMD desalination.

Modification of Nanofiber Support Layer for Thin Film Composite forward Osmosis Membranes via Layer-by-Layer Polyelectrolyte Deposition.

Electrospun nanofiber-supported thin film composite membranes are among the most promising membranes for seawater desalination via forward osmosis. In this study, a high-performance electrospun polyvinylidenefluoride (PVDF) nanofiber-supported thin film composite (TFC) membrane was successfully fabricated after molecular layer-by-layer polyelectrolyte deposition. Negatively-charged electrospun polyacrylic acid (PAA) nanofibers were deposited on electrospun PVDF nanofibers to form a support layer consisted of PVDF and PAA nanofibers. This resulted to a more hydrophilic support compared to the plain PVDF nanofiber support. The PVDF-PAA nanofiber support then underwent a layer-by-layer deposition of polyethylenimine (PEI) and PAA to form a polyelectrolyte layer on the nanofiber surface prior to interfacial polymerization, which forms the selective polyamide layer of TFC membranes. The resultant PVDF-LbL TFC membrane exhibited enhanced hydrophilicity and porosity, without sacrificing mechanical strength. As a result, it showed high pure water permeability and low structural parameter values of 4.12 L m−2 h−1 bar−1 and 221 µm, respectively, significantly better compared to commercial FO membrane. Layer-by-layer deposition of polyelectrolyte is therefore a useful and practical modification method for fabrication of high performance nanofiber-supported TFC membrane.

Platinum Deposited on Carbon Supports for the Complete Detoxification of Formaldehyde at Room Temperature under Humid Conditions

AbstractUniform platinum nanoparticles are deposited on porous carbon supports using a polymeric precursor method. The presented approach has a high potential since hydrophilic and hydrophobic carbon supports are homogeneously impregnated without any preliminary treatment. The platinum nanoparticles on porous carbon composites show a high catalytic activity in the complete detoxification of formaldehyde. Catalysts with platinum loading as low as 0.75 wt.% enable a complete conversion of 700 ppm formaldehyde into carbon dioxide at a relative humidity up to 60% at room temperature. We assign this remarkable catalytic acitivty to a symbiotic effect of the platinum nanoparticles with the carbon support in terms of an oversolubility of formaldehyde in water confined in the pores of the support material.

Aromatic solvent-assisted interfacial polymerization to prepare high performance thin film composite reverse osmosis membranes based on hydrophilic supports

We report an aromatic solvent-assisted interfacial polymerization (IP) method to prepare high performance thin film composite reverse osmosis (RO) membranes based on a polyacrylonitrile support. The use of toluene and xylene as an organic solvent phase led to excellent water flux and unprecedentedly high NaCl rejection (∼99.9%), exceeding both the control membrane prepared using a conventional aliphatic solvent (n-hexane) and commercial RO membranes. The membrane prepared using n-hexane had a thick and moderately dense PA layer, due to the limited amine monomer diffusion, accounting for its relatively low performance. In contrast, the membranes fabricated using toluene/xylene had roof-like structures covering a thin and highly dense basal PA layer, which was formed by increased amine diffusion and an expanded miscible interface zone resulting from the enhanced miscibility of toluene/xylene with water. The excellent membrane performance achieved using toluene/xylene can be attributed to the thin and highly cross-linked basal PA layer.

Modification of Salt‐Templated Carbon Surface Chemistry for Efficient Oxidation of Glucose with Supported Gold Catalysts

AbstractGold nanoparticles dispersed on high‐surface‐area carbon materials were investigated as heterogeneous catalysts for the selective oxidation of d‐glucose to d‐gluconic acid in aqueous solution with molecular oxygen. Salt‐templated porous carbon supports were obtained from different precursors with and without nitrogen and treated under air or hydrogen atmosphere to functionalize the surface with nitrogen, oxygen, or hydrogen. The influence of the surface atomic structure of the carbonaceous supports with similar pore structure on the size and catalytic properties of the metallic nanoparticles was studied at gold nanoparticle loadings of 0.4–0.7 wt %. The functionalisation significantly influences the surface polarity of the support materials and the strength of the interaction with the gold nanoparticles. The surface polarity influences the structure and properties of the catalysts because both the gold deposition and the glucose oxidation reaction take place in the aqueous phase. Rather hydrophilic supports are obtained by doping with oxygen and nitrogen and lead to large gold nanoparticles with low catalytic activity. In contrast, the rather hydrophobic as‐made and hydrogen‐treated supports provide higher catalytic activity (metal time yield up to 1.5 molGlucose molAu−1 s−1) resulting from their smaller gold particles of 3–5 nm in diameter.

Dominant Effect of Support Wettability on the Reaction Pathway for Catalytic Wet Air Oxidation over Pt and Ru Nanoparticle Catalysts

Support wettability can play a key role in directing the activation of oxygen during catalytic wet air oxidation over nanoparticle catalysts. When the nanoparticles are composed of metallic Pt, the optimum support is hydrophobic, but when they are ionic Ru, a hydrophilic support is more effective. This reversal in support effect is consistent with two distinct surface pathways: one in which gas-phase O2 is directly adsorbed on the Pt0 surface and the other in which dissolved O2 is activated on RuO2 immersed in the contaminated aqueous phase. The known effects of ceria on these precious metal catalysts are of secondary importance to support wettability.

Carbon Nanotubes and Algal Polysaccharides To Enhance the Enzymatic Properties of Urease in Lipid Langmuir-Blodgett Films.

Algal polysaccharides (extracellular polysaccharides) and carbon nanotubes (CNTs) were adsorbed on dioctadecyldimethylammonium bromide Langmuir monolayers to serve as a matrix for the incorporation of urease. The physicochemical properties of the supramolecular system as a monolayer at the air-water interface were investigated by surface pressure-area isotherms, surface potential-area isotherms, interfacial shear rheology, vibrational spectroscopy, and Brewster angle microscopy. The floating monolayers were transferred to hydrophilic solid supports, quartz, mica, or capacitive electrolyte-insulator-semiconductor (EIS) devices, through the Langmuir-Blodgett (LB) technique, forming mixed films, which were investigated by quartz crystal microbalance, fluorescence spectroscopy, and field emission gun scanning electron microscopy. The enzyme activity was studied with UV-vis spectroscopy, and the feasibility of the thin film as a urea sensor was essayed in an EIS sensor device. The presence of CNT in the enzyme-lipid LB film not only tuned the catalytic activity of urease but also helped to conserve its enzyme activity. Viability as a urease sensor was demonstrated with capacitance-voltage and constant capacitance measurements, exhibiting regular and distinctive output signals over all concentrations used in this work. These results are related to the synergism between the compounds on the active layer, leading to a surface morphology that allowed fast analyte diffusion owing to an adequate molecular accommodation, which also preserved the urease activity. This work demonstrates the feasibility of employing LB films composed of lipids, CNT, algal polysaccharides, and enzymes as EIS devices for biosensing applications.

On the optimization of low-cost FDM 3D printers for accurate replication of patient-specific abdominal aortic aneurysm geometry

BackgroundThere is a potential for direct model manufacturing of abdominal aortic aneurysm (AAA) using 3D printing technique for generating flexible semi-transparent prototypes. A patient-specific AAA model was manufactured using fused deposition modelling (FDM) 3D printing technology. A flexible, semi-transparent thermoplastic polyurethane (TPU), called Cheetah Water (produced by Ninjatek, USA), was used as the flexible, transparent material for model manufacture with a hydrophilic support structure 3D printed with polyvinyl alcohol (PVA). Printing parameters were investigated to evaluate their effect on 3D–printing precision and transparency of the final model. ISO standard tear resistance tests were carried out on Ninjatek Cheetah specimens for a comparison of tear strength with silicone rubbers.ResultsIt was found that an increase in printing speed decreased printing accuracy, whilst using an infill percentage of 100% and printing nozzle temperature of 255 °C produced the most transparent results. The model had fair transparency, allowing external inspection of model inserts such as stent grafts, and good flexibility with an overall discrepancy between CAD and physical model average wall thicknesses of 0.05 mm (2.5% thicker than the CAD model). The tear resistance test found Ninjatek Cheetah TPU to have an average tear resistance of 83 kN/m, higher than any of the silicone rubbers used in previous AAA model manufacture. The model had lower cost (4.50 GBP per model), shorter manufacturing time (25 h 3 min) and an acceptable level of accuracy (2.61% error) compared to other methods.ConclusionsIt was concluded that the model would be of use in endovascular aneurysm repair planning and education, particularly for practicing placement of hooked or barbed stents, due to the model’s balance of flexibility, transparency, robustness and cost-effectiveness.

Mesh-Embedded Polysulfone/Sulfonated Polysulfone Supported Thin Film Composite Membranes for Forward Osmosis.

In this work, mesh-embedded polysulfone (PSU)/sulfonated polysulfone (sPSU) supported thin film composite (TFC) membranes were developed for forward osmosis (FO). The robust mesh integrated in PSU/sPSU sublayer imparts impressive mechanical durability. The blending of hydrophilic sPSU in PSU sublayer affects the hydrophilicity, porosity, pore structure, and pore size of mesh-embedded PSU/sPSU substrates, and the total thickness, cross-linking degree, and roughness of the corresponding TFC-FO membrane active layers. An appropriate incorporation of sPSU not only significantly decreases the structural parameter, S of the mesh-embedded substrate to 220 μm, which is the lowest reported value for fabric backed FO membrane, but also optimizes the permselectivity of the formed active layer. Regarding the osmosis performance, TFC membranes with sPSU modified substrates gain a higher water flux (Jw) while keeping the specific reverse salt flux (Js/Jw) low. The optimal TFC-FO membrane has a Jw of 31.76 LMH with Js/Jw of 0.19 g/L in FO mode when using deionized water feed and 1 M NaCl draw solution. This paper is practical for developing TFC-FO membrane on hydrophilic support membrane materials.

Architecture and physicochemical characterization of Bacillus biofilm as a potential enzyme immobilization factory

Biocatalysis for industrial application is based on the use of enzymes to perform complex transformations. However, these systems have some disadvantage related to the costs of the biocatalyst. In this work, an alternative strategy for producing green immobilized biocatalysts based on biofilm was developed.A study of the rheological behavior of the biofilm from Bacillus sp. Mcn4, as well as the determination of its composition, was carried out. The dynamic rheological measurements, viscosity (G”) and elasticity (G') module, showed that the biofilm presents appreciable elastic components, which is a recognized property for enzymes immobilization. After the partial purification, the exopolysaccharidewas identified as a levan with a non-Newtonian behavior. Extracellular DNA with fragments between 10,000 and 1000bp was detected also in the biofilm, and amyloid protein in the extracellular matrix using a fluorescence technique was identified. Bacillus sp. Mcn4 biofilms were developed on different surfaces, being the most stable those developed on hydrophilic supports. The biofilm showed lipase activity suggesting the presence of constitutive lipases entrapped into the biofilm. Indeed, two enzymes with lipase activity were identified in native PAGE. These were used as biocatalysts, whose reuse showed a residual lipase activity after more than one cycle of catalysis. The components identified in the biofilm could be the main contributors of the rheological characteristic of this material, giving an exceptional environment to the lipase enzyme. Based on these findings, the current study proposes green and natural biopolymers matrix as support for the enzyme immobilization for industrial applications.

Synthesis and characterization of tethered lipid assemblies for membrane protein reconstitution (Review).

Biological membranes and their related molecular mechanisms are essential for all living organisms. Membranes host numerous proteins and are responsible for the exchange of molecules and ions, cell signaling, and cell compartmentation. Indeed, the plasma membrane delimits the intracellular compartment from the extracellular environment and intracellular membranes. Biological membranes also play a major role in metabolism regulation and cellular physiology (e.g., mitochondrial membranes). The elaboration of membrane based biomimetic systems allows us to reconstitute and investigate, in controlled conditions, biological events occurring at the membrane interface. A whole variety of model membrane systems have been developed in the last few decades. Among these models, supported membranes were developed on various hydrophilic supports. The use of solid supports enables the direct use of surface sensitive techniques (e.g., surface plasmon resonance, quartz crystal microbalance, and atomic force microscopy) to monitor and quantify events occurring at the membrane surface. Tethered bilayer membranes (tBLMs) could be considered as an achievement of the first solid supported membranes described by the McConnell group. Tethered bilayers on solid supports were designed to delimit an inside compartment from an outside one. They were used for measuring interactions with ligands or incorporating large membrane proteins or complexes without interference with the support. In this context, the authors developed an easy concept of versatile tBLMs assembled on amino coated substrates that are formed upon the vesicle fusion rupture process applicable to protein-free vesicles as well as proteoliposomes. The phospholipid bilayer (natural or synthetic lipids) incorporated 5% of 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-poly ethylene glycol-N-hydroxy succinimide to ensure the anchorage of the bilayer to the amino coated surface. The conditions for the formation of tBLMs on amino-coated gold and glass were optimized for protein-free vesicles. This biomimetic membrane delimits an inside "trans" compartment separated from an outside reservoir "cis." Using this tBLM construction, the authors were interested in deciphering two complex molecular mechanisms involving membrane-associated proteins. The first one concerns two mitochondrial proteins, i.e., the porin voltage dependent anion channel (VDAC) embedded in the outer membrane and the nucleotide transporter (adenine nucleotide translocase) that interacts dynamically during mitochondrial pathophysiology. The purified VDAC porin was first reconstituted in proteoliposomes that were subsequently assembled on an amino coated support to form a biomimetic membrane. As a major result, VDAC was reconstituted in this tBLM and calcium channeling was demonstrated across the lipid bilayer. The same two-compartment biomimetic membrane design was further engineered to study the translocation mechanism of a bacterial toxin, the adenylate cyclase toxin, CyaA, from Bordetella pertussis. As a result, the authors developed an elegant in vitro translocation toolkit applicable to potentially a large panel of proteins transported across membranes.

Substrate Effects in Graphene‐Based Electric Double‐Layer Capacitors: The Pivotal Interplays between Ions and Solvents

AbstractGraphene has been considered as a promising active material for electric double‐layer capacitors (EDLCs), primarily owing to its extraordinary monolayer properties, whereas the interfacial behaviors are conspicuously impacted by underlying substrates. In this work, substrate effects on the interfacial wettability, EDL structure, and capacitive behavior of graphene‐based EDLCs are delineated with numerical simulation. Unlike previous studies, a partial wetting transparency of topmost graphene is recognized for hydrophilic supports. In particular, a virtually identical capacitance is demonstrated for graphene with various supports, albeit the substantially different EDL structures stemmed from substrate effects. The achieved invariant capacitance is prominently attributed to the counterbalancing correlations between ions and proximal solvents, going beyond traditional views of modulating capacitance preferentially through ion structural evolutions. Specifically, the suppressed permittivity of apparently ordered water dipoles (i. e. detrimental solvent effects) attenuates the beneficial ionic influences (i. e. reinforced population and closer approach) on shielding the external electric fields. The as‐obtained findings demonstrate the paramount importance of the substrate in mediating interfacial behaviors within electrified EDLC systems and highlight that exploiting the pivotal interplay between ions and solvents could be a novel avenue to further manipulate electrochemical performances.

Increase in the length of poly(ethylene oxide) blocks in amphiphilic copolymers facilitates their cellular uptake

ABSTRACTAmphiphilic nonionic block copolymers induce different biological effects on living cells. In particular, the hydrophobic members of the Pluronics family suppress drug efflux systems in multidrug‐resistant cells, whereas hydrophilic Pluronics support cell viability. However, the relationship between the copolymer structure and its binding to cells is still unclear. Using a tritium‐labeling approach, we analyzed interactions of nine Pluronics and three diblock copolymers with human and murine cells in vitro and revealed that the binding efficiency of the copolymers increased in line with the length of their poly(ethylene oxide) (PEO) blocks. In contrast, partitioning of the same polymers into artificial lipid bilayers determined by Isothermal Titration Calorimetry (ITC) decreased with increasing length of the PEO block. The opposite influence of hydrophilic blocks on the copolymer affinity to living cells and artificial lipid bilayers implied the binding of long PEO blocks to the hydrophilic moieties of cellular membranes. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45492.

Preparation and characterization of a thin-film composite reverse osmosis membrane using a polysulfone membrane including metal-organic frameworks

The objectives of this paper were to elucidate the performance of a thin-film composite (TFC) reverse osmosis (RO) membrane by modifying the support layer. In order to improve the hydrophilicity and porosity of the support layer, we prepared a polysulfone (PSf) membrane containing an HKUST-1 [Cu3(BCT2)] metal organic framework (MOF) treated with sulfuric acid for the stability of water. N,N-dimethylformamide (DMF)/water was used as the solvent/non-solvent pair, and the TFC RO membrane was formed by the interfacial polymerization of m-phenylene diamine (MPD) in aqueous solution with trimesoyl chloride (TMC) in organic solution on the MOF/PSF support layer. The optimized concentration of MPD-TMC was investigated through XPS, and the manufactured membrane had a thin, smooth film when paired with a hydrophilic and porous support layer. The active layer thickness of novel membrane was 0.029µm via FTIR analysis that the thickness compared to a commercial RO membrane having a thickness of 0.2µm. Also, the novel membrane showed improved flux and fouling resistance compared to the TFC RO membrane with a PSF support layer, without altering the salt rejection property.

Hydrazide-functionalized affinity on conventional support materials for glycopeptide enrichment.

In affinity chromatography, enrichment of biomolecules is dependent on the selection of affinity sites immobilized onto a suitable support material. A few hydrazide - functionalized materials with surface modification protocols compatible to conventional support materials like silica and cellulose are reported. The study demonstrates the modification/derivatization pathways that can be adopted to modify the support materials with similar surface chemistry like cellulose, poly(GMA/DVB), or diamond. Poly(GMA/DVB) and cellulose represent hydrophilic supports whereas diamond isa hydrophobic support material. SEM images of three materials provide surface morphology whereas FT-IR confirms reaction completion and derivatization. These hydrazide - functionalized materials are applied to fetuin digest for glycopeptides enrichment and subsequently for selectivity and sensitivity assessment. Statistically, poly(GMA/DVB) shows 85.7% sensitivity with specificity of 88.8% in the enrichment experiments. Diamond offers hydrophobic interactions to non-glycopeptides and they co-elute with glycopeptides, resulting in reduced sensitivity down to 69.2%. Poly(GMA/DVB) shows recovery up to 89%, while recovery for cellulose and diamond is 83 and 71%, respectively. The materials enrich mono-N-linked-glycosylated peptide from tryptic digest of chicken avidin spiked in fetuin digest. The hydrazide group density on cellulose, poly(GMA/DVB), and diamond is 2.8, 2.3, and 2.1mmol/g, respectively; this contributes towards the specificity and sensitivity of designed materials. The materials are also applied to serum samples and enriched glycopeptides characteristic of serum glycoproteins of clinical importance. Therefore this study provides routes for the economical surface modifications of support materials and to fabricate affinity materials with improved efficiency. Graphical Abstract Glycopeptides enrichment by hydrazine affinity.