Amine Research Articles

One-pot Functionalization for the Preparation of Cobaltocene-Modified Redox-Responsive Porous Microparticles.

Porous organic cobaltocenium-containing particles are scarce in literature but highly interesting for their electrochemical properties and reusability in, for example, catalysis or magnetic systems. In this work, we present a scalable one-pot strategy to introduce tailorable amounts of cobaltocenium on a porous substrate, adjusting the electrochemical switching capability. For this purpose, 3-(triethoxysilyl)propan-1-amine (APTES) and ethynyl cobaltocenium hexafluorophosphate is used as functionalization agents for in-situ catalyst-free hydroamination, followed by silane condensation at the particles' surface. Functionalized particles are characterized by attenuated total reflection infrared spectroscopy (ATR-IR), thermogravimetric analysis (TGA), laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), inductively coupled plasma mass spectrometry (ICP-MS), powder X-ray diffraction (PXRD) and cyclic voltammetry (CV) showing excellent control over the degree of functionalization, i. e., the added cobaltocenium reagents. The electrochemical stability and good addressability while preserving the porous structure are shown. By utilizing higher amounts of APTES, the overall cobaltocenium amount can be reduced in favor of additional amine groups, strongly affecting the electrochemical behavior, making this functionalization strategy a good platform for metallopolymer immobilization and tailored functionalization. Additionally, thermal treatment of the synthesized metallopolymer microparticles paves the way to magnetic properties with tailorable microporous architectures for end-of-life and upcycling aspects.

Chitosan/Poly(maleic acid-alt-vinyl acetate) Hydrogel Beads for the Removal of Cu2+ from Aqueous Solution.

Covalent cross-linked hydrogels based on chitosan and poly(maleic acid-alt-vinyl acetate) were prepared as spherical beads. The structural modifications of the beads during the preparation steps (dropping in liquid nitrogen and lyophilization, thermal treatment, washing with water, and treatment with NaOH) were monitored by FT-IR spectroscopy. The hydrogel beads have a porous inner structure, as shown by SEM microscopy; moreover, they are stable in acidic and basic pH due to the covalent crosslinking. The swelling degree is strongly influenced by the pH since the beads possess ionizable amine and carboxylic groups. The binding capacity for Cu2+ ions was examined in batch mode as a function of sorbent composition, pH, contact time, and the initial concentration of Cu2+. The kinetic data were well-fitted with the pseudo-second-order kinetic, while the sorption equilibrium data were better fitted with Langmuir and Sips isotherms. The maximum equilibrium sorption capacity was higher for the beads obtained with a 3:1 molar ratio between the maleic copolymer and chitosan (142.4 mg Cu2+ g-1), compared with the beads obtained using a 1:1 molar ratio (103.7 mg Cu2+ g-1). The beads show a high degree of reusability since no notable decrease in the sorption capacity was observed after five consecutive sorption/desorption cycles.

Remediation of Heavy Metal Pollution from Coal Mine Effluent Using Metal-Organic Frameworks (MOF): Impact of Water Media, Operational Factors and Metal Characteristics

The energy sector is the sector that generates the highest amount of environmental contamination, especially in water sources, mostly in the case of coal-based energy production. The aim of this study was to examine a significant contamination source, heavy metal contamination, in coal mining effluents. The current investigation introduces an MOF platform based on zirconium clusters and isophthalic acid with NH2-MIP-SO3H mixed amine and sulfonic acid functional groups in order to remove the most common heavy metal ions in coal mining effluents, including Hg, Cd, Pb, and Cu ions. The water matrix and the operational conditions were identified to be very influential in the removal process, such as the pH of water, the initial metal concentration and operating time. NH2-MIP-SO3H offers a great removal efficiency of metals starting from 745.83 mg/g for Cd, 673.67 mg/g for Cu, 589.85 mg/g for Hg, and 481.66 mg/g for Pb ions, with the Langmuir equation for equilibrium and pseudo-second-order equation for kinetics being the ideal models to express the equilibrium and kinetic data, respectively. A significant impact of water pH was found to occur, with the NH2-MIP-SO3H platform performing best at pH 6. Reuse of NH2-MIP-SO3H demonstrates excellent reusability, sustaining 90% of initial performance over eight regeneration cycles. The interaction of functional group-functional metal was the dominant mechanism in the removal process. The NH2-MIP-SO3H unique approach to heavy metal removal provides a very hopeful outlook for additional investigations in larger-scale studies.

Coordination chemistry of 4-aminopyrazole: Structure and physicochemical properties of cobalt(II) chlorido complexes, and amino group reactivity towards a ketone to yield an imine bond

An outline of the in situ construction of a coordination polymer by reacting a mononuclear cobalt(II) complex, functionalised with an amine substituent, with acetone is given. The methodology involved 4-amino-3,5-diisopropyl-1-pyrazole (denoted as L1pzHNH2) as the precursor, putative linker molecule. Reaction of the ligand with anhydrous cobalt(II) chloride, yielded a four-coordinated cobalt(II) chlorido complex, [CoCl2(L1pzHNH2)2]. When the complex was reacted with acetone, a four-coordinated cobalt(II) chlorido coordination polymer, [CoCl2{L1pzHN=C(CH3)2}]n, with an imine bond, was obtained. The complexes were characterised by various spectroscopic techniques. X-ray crystallography shows [CoCl2(L1pzHNH2)2]·2(thf) to comprise a tetrahedrally coordinated cobalt(II) centre with the donors being two chlorido and two pyrazolyl-N atoms. Similarly, [CoCl2{L1pzHN=C(CH3)2}]n features a Cl2N2 donor set defining an approximately tetrahedral geometry with the imine-N donors being derived from a pyrazolyl ring and a symmetry related exocyclic imine-N atom with the result that a one-dimensional coordination polymer with a helical topology is formed. When the uncoordinated precursor molecule, L1pzHNH2, was reacted with acetone, the formation of the imine was confirmed by 1H NMR measured in (CD3)2CO solution. However, from the 1H NMR measured for the imine in CDCl3 solution, a 70:30 equilibrium between the imine and amine was established. It is concluded that the nucleophilicity of the amine group is enhanced by the binding of cobalt(II) to the pyrazole nitrogen in [CoCl2(L1pzHNH2)2]·2(thf), thereby favouring irreversible imine formation. The facile formation of [CoCl2{L1pzHN=C(CH3)2}]n in the solid-state also correlates with the reduced solubility of the coordination polymer structure in organic solvents.

Recent developments in metal-catalysed transamidation of quiescent amides

Amides played a vital role in the development of organic synthesis in recent years. These structural motifs are found in several biologically important synthetic and naturally occurring compounds. Developing efficient methods for their synthesis is crucial for drug discovery. Transamidation is a prominent tool in organic and medicinal chemistry, enabling the replacement of the amine group in an existing amide with new functionalised amines. Additionally, Transamidation process is used significantly in the total synthesis of few naturally occurring compounds. Transamidation reaction has been achieved significantly by using metal catalysis but there are several metal-free approaches have been employed to achieve the same reaction. This review focuses on recent literature concerning metal-catalysed transamidation reactions, highlighting the use of alkaline earth metals, transition metals, lanthanides, actinides, alkali metal salts or complexes, and metalloids. Both catalytic and stoichiometric quantities of catalysts are discussed for their roles in enhancing reaction efficiency.

Increased Cytotoxicity of Bimetallic Ultrasmall Silver-Platinum Nanoparticles (2 nm) on Cells and Bacteria in Comparison to Silver Nanoparticles of the Same Size.

Ultrasmall nanoparticles (diameter 2 nm) of silver, platinum, and bimetallic nanoparticles (molar ratio of Ag:Pt 0:100; 20:80; 50:50; 70:30; 100:0), stabilized by the thiolated ligand glutathione, were prepared and characterized by transmission electron microscopy, differential centrifugal sedimentation, X-ray photoelectron spectroscopy, small-angle X-ray scattering, X-ray powder diffraction, and NMR spectroscopy in aqueous dispersion. Gold nanoparticles of the same size were prepared as control. The particles were fluorescently labeled by conjugation of the dye AlexaFluor-647 via copper-catalyzed azide-alkyne cycloaddition after converting amine groups of glutathione into azide groups. All nanoparticles were well taken up by HeLa cells. The cytotoxicity was assessed with an MTT test on HeLa cells and minimal inhibitory concentration (MIC) tests on the bacteria Escherichia coli and Staphylococcus xylosus. Notably, bimetallic AgPt nanoparticles had a higher cytotoxicity against cells and bacteria than monometallic silver nanoparticles or a physical mixture of silver and platinum nanoparticles. However, the measured release of silver ions from monometallic and bimetallic silver nanoparticles in water was very low despite the ultrasmall size and the associated high specific surface area. This is probably due to the surface protection by a dense layer of thiolated ligand glutathione. Thus, the enhanced cytotoxicity of bimetallic AgPt nanoparticles is caused by the biological environment in cell culture media, together with a polarization of silver by platinum.

Probing Self-Assembly of Ammeline in Chloroform and Aqueous Media: Interplay Between Hydrogen Bonding Diversity and Dimerization.

Ammeline (AM) is a molecule with a very low reputation in the field of supramolecular community, but with a recently proven potential both experimentally and theoretically. In this work, dispersion-corrected density functional theory (DFT-D) computations and molecular dynamics (MD) simulations were employed to understand the aggregation mechanism of AM in chloroform and water media. Our DFT-D and MD analyzes show that the most important interactions are those formed by the amine groups (-NH2) with both the pyridine-type nitrogen atoms and the carbonyl groups (C=O). In the more polar solvent, the interactions between water molecules and the C=O group prevent the AM from forming more interactions with itself. Nevertheless, four types of dimers involving N-H∙∙∙O interactions were found to exist in water solutions. The overlooked tetrel bond between endocyclic N and C atoms can also stabilize dimers in solution. Moreover, while most AM dimers are enthalpy-driven, our results indicate that the unique DD-AA dimer (D=donor, A=acceptor) that originates cyclic rosettes is entropy-driven.

Theranostics Using MCM-41-Based Mesoporous Silica Nanoparticles: Integrating Magnetic Resonance Imaging and Novel Chemotherapy for Breast Cancer Treatment.

Advanced breast cancer remains a significant oncological challenge, requiring new approaches to improve clinical outcomes. This study investigated an innovative theranostic agent using the MCM-41-NH2-DTPA-Gd3⁺-MIH nanomaterial, which combined MRI imaging for detection and a novel chemotherapy agent (MIH 2.4Bl) for treatment. The nanomaterial was based on the mesoporous silica type, MCM-41, and was optimized for drug delivery via functionalization with amine groups and conjugation with DTPA and complexation with Gd3+. MRI sensitivity was enhanced by using gadolinium-based contrast agents, which are crucial in identifying early neoplastic lesions. MIH 2.4Bl, with its unique mesoionic structure, allows effective interactions with biomolecules that facilitate its intracellular antitumoral activity. Physicochemical characterization confirmed the nanomaterial synthesis and effective drug incorporation, with 15% of MIH 2.4Bl being adsorbed. Drug release assays indicated that approximately 50% was released within 8 h. MRI phantom studies demonstrated the superior imaging capability of the nanomaterial, with a relaxivity significantly higher than that of the commercial agent Magnevist. In vitro cellular cytotoxicity assays, the effectiveness of the nanomaterial in killing MDA-MB-231 breast cancer cells was demonstrated at an EC50 concentration of 12.6 mg/mL compared to an EC50 concentration of 68.9 mg/mL in normal human mammary epithelial cells (HMECs). In vivo, MRI evaluation in a 4T1 syngeneic mouse model confirmed its efficacy as a contrast agent. This study highlighted the theranostic capabilities of MCM-41-NH2-DTPA-Gd3⁺-MIH and its potential to enhance breast cancer management.

Synthesis, evaluation and structure-activity relationship studies of pterodontic acid acylated derivatives with anti-flu A virus (H1N1) activity in vitro

In order to develop antiviral drugs, we utilized pterodontic acid (Poa-1) as a lead compound and conducted various modifications, including oxidation, reduction, addition, esterification, and acylation, resulting in the synthesis of 29 derivatives, of which 25 were novel acylation derivatives. Cell-level validation demonstrated that 4 derivatives exhibited significant inhibitory effects on the influenza A virus (H1N1), with an IC50 = 4.04–36.13 μM. Notably, four acylation derivatives (compounds IIE5, IIE6, IIE9, and IIE17) exhibited specific antiviral activities against influenza A virus (H1N1) with low cytotoxicity, indicating favorable therapeutic indices (SI = 3.5–11.9). Structure-activity relationship studies indicated that C5–C6 olefins are essential groups for antiviral activity, C11–C12 conjugated olefins will not interfere with antiviral activity. Carboxylic acid is an essential group for activity. Moreover，Carboxylic acid acylation can improve antiviral activity, and the inclusion of guanidine, cyclic amine, and phenyl groups with electron-donating substituents could enhance the antiviral activity of the lead compound. Natural products structural modifications are capable of improving the biological activity of lead compounds, offering a rapid pathway for the development of potent new structures.

SYNTHESIS OF NEW ADSORBENTS VIA FUNCTIONALIZED MCM-41 FOR THE REMOVAL OF SOME IONS FROM AQUEOUS SOLUTION

Background: Mesoporous materials like MCM-41 silica are highly regarded for their structural features and applications in adsorption and catalysis. This study enhances MCM-41's ability to adsorb cobalt and copper ions by introducing amine and Schiff-base groups, boosting its affinity for these pollutants and aiding in their removal from water solutions. Aims: To prepare MCM-41@NTPE and MCM-41@NTPE-BSAL and use them to adsorb heavy pollutants like cobalt and copper divalent ions from aqueous solutions. Methods: Mesoporous materials (MCM-41@NTPE and MCM-41@NTPE-BSAL) derived from rice husk were used as low-cost adsorbents for the adsorption of Co(II) and Cu(II) ions from aqueous solutions. Uptake experiments were performed to determine adsorption parameters like ion concentration, pH, exposure time, and adsorbent mass. Results: MCM-41@NTPE and MCM-41@NTPE-BSAL were characterized by FT-IR, FESEM-EDX, TEM, N2-adsorption–desorption, XRD,AFM and TGA/DTA. FT-IR confirmed the presence of silanol and siloxane groups. XRD and TEM indicated highly ordered hexagonal arrangements. N2–adsorption–desorption analysis revealed average pore diameters of 42.468 nm and 40.417 nm, total pore volumes of 0.094 cm3g?1 and 0.3384 cm3g?1, and specific surface areas of 8.873 m2g?1 and 37.802 m2g?1 for MCM-41@NTPE and MCM-41@NTPE-BSAL, respectively. TGA showed three mass reduction steps. Adsorption assessment showed pH 6 and 5 were optimal for Co(II) and Cu(II) uptake, respectively, and uptake increased with initial concentration and exposure time. Discussion: XRD confirmed the hexagonal mesoporous structure, while BET analysis displayed amorphous natures. TGA suggested MCM-41@NTPE and MCM-41@NTPE-BSAL have potential for stability, although decomposing between 15-900°C. Electron microscopy revealed ordered hexagonal arrangements. The materials demonstrated high efficacy in extracting copper and cobalt ions from aqueous solutions. Conclusions: Two mesoporous silica materials (MCM-41@NTPE and MCM-41@NTPE-BSAL) were prepared from rice husk by functionalizing MCM-41. Adsorption assessment showed uptake depended on exposure time, pH, initial concentration, and adsorbent mass. MCM-41@NTPE-BSAL exhibited better ion uptake than MCM-41@NTPE.

Development of a quaternary photocurable system for 3D printing based on the addition of acrylate monomers to an epoxy/thiol‐Ene system

AbstractThe exothermic nature of acrylate photopolymerizations enables room temperature 3D printing of a quaternary formulation that incorporates an acrylate monomer, and an epoxy/thiol‐ene system (ETES). The latter comprises an epoxy monomer, a multifunctional thiol and a tetraallyl functionalized ditertiary amine curing agent. Pristine ETES necessitates temperatures of 85–95 °C for curing. Several mechanisms operate simultaneously during this process: homopolymerization of acrylates, thiol‐acrylate photopolymerization, thiol‐ene photopolymerization between the double bonds of curing agent and the multifunctional thiol, the Michael addition between thiolates derived from ETES and the double bonds of acrylates, and the anionic polymerization of the epoxy resin via the tertiary amine groups. To optimize the quaternary formulations for printing, parameters, such as reactivity, exothermicity, and viscosity, was explored. Subsequently, the thermal and viscoelastic properties of the printed cross‐linked polymers derived from these formulations were analyzed using Differential Scanning Calorimetry (DSC), Dynamic Mechanical Analysis (DMA) and Thermogravimetric Analysis (TGA). The polymers derived from quaternary formulations exhibited lower crosslinked density compared to those obtained from the pristine acrylates. This reduction in crosslink density contributes to the improved toughness of the hybrid polymers.

Multisite Amino‐Allylidene Ligands from Thermal CO Elimination in Diiron Complexes and Catalytic Activity in Hydroboration Reactions

AbstractThe new diiron(I) complexes [Fe2Cp2(μ‐CO){μ‐k3C,kN‐C(R1)C(R2)C(CN)NMe(R)}], 3 a–o (R=alkyl or 4‐C6H4OMe; R1=alkyl, aryl, ferrocenyl (Fc), thiophenyl, CO2Me or SiMe3; R2=H, Me or CO2Me) were synthesized in moderate to high yields from the thermal decarbonylation of the bis‐carbonyl precursors 2 a–o, and were structurally characterized by IR and NMR spectroscopy, and single crystal X‐ray diffraction in four cases. Electrochemical behavior of one complex was also investigated. Complexes 3 a–o comprise a highly functionalized, multisite amino‐(cyano)allylidene ligand, including metal coordination of a tertiary amine group. Selected complexes displayed negligible to moderate catalytic activity in CO2/propylene oxide coupling, working under ambient conditions. Additionally, they were investigated as catalysts for the conversion of benzaldehyde to the corresponding borate ester 6 a, using pinacolborane (HBpin) as the borylating agent. Most complexes achieved good conversions at room temperature with 1 % catalyst loading, and data highlight the significant influence of the multisite ligand substituents on the catalytic performance. Notably, complex 3 m (featuring R=4‐methoxyphenyl, R1=Fc, R2=H) displayed the highest activity and effectively catalyzed the hydroboration of various aldehydes and ketones. A plausible mechanistic cycle involves metal coordination of the carbonyl substrate, its activation being possibly facilitated by intramolecular interactions.

Computational and Experimental IM-MS Determination of the Protonated Structures of Antimalarial Drugs.

A combination of ion mobility-mass spectrometry (IM-MS) measurements and computational methods were used to study structural and physicochemical properties of a range of quinoline-based drugs: amodiaquine (AQ), cinchonine (CIN), chloroquine (CQ), mefloquine (MQ), pamaquine (PQ), primaquine (PR), quinacrine (QR), quinine (QN), and sitamaquine (SQ). In experimental studies, ionization of these compounds using atmospheric pressure chemical ionization (APCI) yields monoprotonated species in the gas phase while electrospray ionization (ESI) also produces diprotonated forms of AQ, CQ, and QR and also for PQ, SQ, and QN in the presence of formic acid as an additive. Comparison of the trajectory-method-calculated and experimental IM-derived collisional cross sections (CCSN2) were used to assign both the protonation sites and conformer geometry of all drugs considered with biases of 0.7-2.8% between calculated and experimental values. It was found that, in solution, AQ and QR are protonated at the ring nitrogen of the quinoline group, whereas the other drugs are protonated at the amine group of the alkyl chain. Finally, the conformers of [M + H]+ and [M + 2H]2+ assigned according to the lowest energies and CCSN2 calculations were used to calculate the pKa values of the antimalarial drugs and the relative abundance of these ions at different pH values that provided validation of the computational and experimental IM-MS results.

A UV-curable silicone acrylate anti-smudge coating containing tertiary amines and Ti with the ability to prevent oxygen inhibition

UV curing technology has numerous advantages such as a fast curing speed, environmental friendliness, energy conservation, and thus it is widely used in industrial production and out daily life. Free-radical polymerization is the primary mechanism for UV curing technology. However, free-radical polymerization is susceptible to oxygen inhibition, which leads to incomplete curing when this approach is employed in the air. This paper describes a new silicone acrylate prepolymer, four double bonds and a tertiary amine group at each end of the prepolymers can effectively solve the oxygen inhibition. We synthesized an alkoxymethacryloxy titanium monomer (Ti-MA). This monomer was mixed with the prepolymer and UV cured, which resulted in improved coating properties. The results showed that the double bond conversion of the prepolymer reached 90.66 ± 0.5 % at 20 s, and the residual adhesion rate also exceeded 90 %. The hardness of the coating could reach pencil hardness level 4H with the addition of Ti-MA, and the water contact angle reached 104.5 ± 0.2°, as well as excellent anti-smudge and anti-fingerprint properties. This study provides a new method to solve the oxygen inhibition problem, which has a broad application prospect in the field of coatings.

Iron-Catalyzed Multicomponent C-H Alkylation of in Situ Generated Imines via Photoinduced Ligand-to-Metal Charge Transfer.

Herein, we describe a novel photoinduced iron-catalyzed strategy for multicomponent C-H alkylation of in situ generated imines. By utilizing the alkyl radicals generated through iron-mediated photocatalytic C-H activation, the imines formed in situ are further subjected to addition reactions, resulting in the synthesis of various secondary and tertiary amine products. This method is simple to operate and does not require additional oxidants. It is applicable to inert alkane substrates such as cyclic alkanes, cyclic ethers, toluene, and ketones. The reaction is also compatible with various aromatic amines, alkyl amines, halogenated aromatic amines, as well as aromatic aldehydes, alkyl aldehydes, and cinnamaldehyde, among other different types of aldehydes.

Effect of adhesion promoters on rheokinetics and roll peel strength of electrical steel stacks

Epoxy varnishes for stacked electrical steel are of high relevance for renewable energy and electric mobility technologies. Water-borne epoxy varnish systems are still under development, especially with regards to the improvement of the adherence to the steel substrate. The main objective of this study was to assess the potential of low molar mass, silane-based adhesion promoters (AP) with amine or glycidyl functional groups as to their effect on the crosslinking kinetics of coatings and the mechanical performance of electrical steel laminates.Model formulations with different types and contents of silane AP or in combination with a pre-crosslinker were based on a Bisphenol A diglycidyl ether, a dicyandiamide (DICY) crosslinking agent and an emulsifier. The amount of water was fixed to 45 m%. Model varnishes were prepared by shear emulsification at elevated temperatures. Varnishes were applied onto electrical steel sheets and partly crosslinked to the B-stage. Finally, coated steel sheets were stacked and laminated in a heated press.To examine the crosslinking kinetics under non-isothermal conditions, rheokinetic measurements were performed. While the curing onset temperature of formulations with amine-based AP dropped by ∼10 °C, the effect of the epoxysilane AP was less pronounced (drop by ∼5 °C). Pre-conditioning of the varnishes in A-stage revealed a further reduction of the curing onset temperature associated with significantly higher initial viscosity. This was a clear indication for pronounced pre-crosslinking in A-stage and hence, a limited shelf life of silane-modified varnishes. The glass transition range in the fully cured state was solely affected by the diamine-based AP. Interestingly, the investigated low molar mass silane APs had no significant positive effect on the roll peel strength of the laminates.

Dual-Regulation of Supramolecular Chirality in Achiral Side-Chain Azobenzene Liquid-Crystalline Polymers.

Azobenzene (Azo) liquid-crystalline polymers are intriguing due to their unique photo-induced isomerization and supramolecular chirality. However, clarification on multicomponent chiral induction towards Azo polymers remains ambiguous and challenging. Herein, chiral solvents and amines were employed to control the chiroptical activity of achiral Azo polymers. Methyl L-/D-lactate was added as the poor solvent and chiral inducer to achieve the first chiral induction in Azo aggregates. Chiral amines were utilized for the second chiral induction based on the acid-base interactions between the carboxyl groups of polymers and amines. The chiral enhancement and inversion of Azo units could be observed through the synergistic or antagonistic effect between solvents and amines. The impacts of solvent, chemical structures, feed ratio, enantiomeric excess, and temperature on supramolecular chirality were systematically studied. Furthermore, this system displayed the chiroptical switching property and chiral recovery under reversible irradiation.

Engineering polyvinylidene fluoride membranes using charge tunable dendrimer polyamidoamine to enable microporous membranes for protein separation

Dendrimers are structurally precise molecules, whose peripheral layer provides ample sites for anchoring functional groups of different charges and charge densities. This characteristic renders them capability of providing numerous target functional groups on the surface of filtration membranes when modified by dendrimers. Consequently, there has been a growing interest in dendrimer-modified membranes. In this study, we investigated the engineering of polyvinylidene fluoride (PVDF) membranes using polyamidoamine (PAMAM) dendrimers anchoring different functional groups to tune the charges and charge density of membranes to enable microporous membranes for separation of charged macromolecules. PVDF membranes were functionalized by grafting PAMAM-G3.0 (generation 3) dendrimers with amine groups onto their surfaces and internal surfaces of membrane pores. Subsequently, the peripheral functional groups of dendrimers on the membranes were replaced by carboxyl groups, quaternary ammonium groups, or sulfonic acid groups for charges of different nature and densities. Surface chemical properties, electrical properties, and morphology were characterized using various techniques, including attenuated total reflectance Fourier-transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and surface zeta potential measurement. The filtration performance of both PVDF and modified membranes was evaluated using polyethylene oxide (PEO), polyacrylic acid (PAA), and whey protein filtration. Among the modified membranes, the G3PA membranes, with carboxyl functional groups, exhibited the most effective whey protein separation performance. The whey protein rejection and permeate flux of the G3PA membranes were 79 % and 30.3 LMH, respectively. As a comparison, the whey protein rejection and permeate flux of the pristine PVDF membranes were 58.9 % and 15.3 LMH, respectively.

Identification of Quiescent Cells in a Zebrafish T-Cell Acute Lymphoblastic Leukemia Model Using Cell Proliferation Staining.

Cellular quiescence is a state of growth arrest or slowed proliferation that is described in normal and cancer stem cells (CSCs). Quiescence may protect CSCs from antiproliferative chemotherapy drugs. In T-cell acute lymphoblastic leukemia (T-ALL) patient-derived xenograft (PDX) mouse models, quiescent cells are associated with treatment resistance and stemness. Cell proliferation dyes are popular tools for the tracking of cell division. The fluorescent dye is covalently anchored into amine groups on the membrane and macromolecules inside the cell. This allows for the tracking of labeled cells for up to 10 divisions, which can be resolved by flow cytometry. Ultimately, cells with the highest proliferation rates will have low dye retention, as it will be diluted with each cell division, while dormant, slower-dividing cells will have the highest retention. The use of cell proliferation dyes to isolate dormant cells has been optimized and described in T-ALL mouse models. Complementary to the existing mouse models, the rag2:Myc-derived zebrafish T-ALL model provides an excellent venue to interrogate self-renewal in T-ALL due to the high frequency of leukemic stem cells (LSCs) and the convenience of zebrafish for large-scale transplant experiments. Here, we describe the workflow for the staining of zebrafish T-ALL cells with a cell proliferation dye, optimizing the concentration of the dye for zebrafish cells, passaging successfully stained cells in vivo, and the collection of cells with varying levels of dye retention by live cell sorting from transplanted animals. Given the absence of well-established cell surface makers for LSCs in T-ALL, this approach provides a functional means to interrogate quiescent cells in vivo. For representative results, we describe the engraftment efficiency and the LSC frequency of high and low dye-retaining cells. This method can help investigate additional properties of quiescent cells, including drug response, transcriptional profiles, and morphology.

Magnetically recoverable molybdate supported silica decorated ferrite nanocat (Fe–Si–Mo) and their utilization for reductive amination of carbonyl compound under benign condition

A magnetite silica-coated nanoparticle-supported molybdate catalyst (Nanocat-Fe-Si-Mo) was successfully prepared by simple co-precipitation techniques. The prepared nanoparticles have been characterized using FE-SEM, EDX, FT-IR, WDX, ICP-OES, TEM, and TGA techniques. Under benign conditions, the catalytic activity of the nanocatalyst was investigated for the reductive amination of carbonyl compounds; a greener methodology is presented that provides a simple and efficient technique for the production of secondary amine utilizing a recyclable nanocatalyst. Notably, 0.09 mg of the catalyst is adequate for the amination of carbonyl compound in the alcoholic medium at room temperature. Significantly, utilizing an external magnet, the nanoparticles have been readily removed among the solution with recovered a minimum of 10 times without losing catalytic activity.