High-Flux lamellar MoSe2 membranes for efficient dye/salt separation.

Membrane-based technology is emerging as an efficient technique for wastewater treatment in recent years. Membranes made up of two-dimensional materials provide high selectivity and water flux compared to conventional polymeric membranes. Herein, we report the synthesis and use of MoSe2 membrane for dye and drug separation in wastewater, mainly from textile and pharmaceutical industries. The as-prepared MoSe2 membrane shows âˆ¼ 100% rejection for organic dyes and ciprofloxacin drug with a water flux reaching up to âˆ¼ 900 Lm-2h-1bar-1. Further, the MoSe2 membrane shows lower NaCl rejection of âˆ¼ 1.9% for the dye/salt mixture. The interlayer spacing in the MoSe2 membrane allows the water molecules and ions from the salt to pass through freely but restricts the movement of large contaminants. The membrane is stable against the bovine albumin serum fouling with a flux recovery rate of 96%. It also shows good performance even in harsh environments (pH 3-10). To the best of our knowledge, the MoSe2 membranes were fabricated for the first time for wastewater treatment application. The dye/salt separation performance of the MoSe2 membrane is significantly better than several other membranes. This work highlights the promising potential for using two-dimensional materials for textile and pharmaceutical wastewater treatment.

Heterostructures of polyaniline and Ce-ZnO nanomaterial coated flexible PET thin films for LPG gas sensing at standard environment.

The n-type Ce doped ZnO (Ce-ZnO) and p-type polyaniline (PANI) heterojunction were successfully synthesized via simple chemical solution method for sensing liquefied petroleum gas (LPG) at standard environment. The morphology and structures of as-prepared Ce-ZnO & PANI nanoparticles were analyzed by numerous kinds of techniques. Ce-ZnO & PANI nanoparticles were mixed with n-methylpyrrolidone (NMP) which is coated over the gold coated PET electrode by doctor blade method and dried overnight at 60 °C to form p-n junction. The as-formed p-n junction is to be driven with the help of 1.5 V potential at ambient temperature. X-ray photoelectron spectroscopy results of Ce-ZnO nanoparticles confirmed the existence of Ce4+ and the improved amount of both chemisorbed oxygen and oxygen vacancy after the formation of Ce-ZnO heterojunction. The maximum response of 80% was realized for hollow Ce-ZnO/PANI sensor at 100 ppm. The proposed material is a novel candidate to detect the LPG even at low (30) ppm and this study reveals the possibility of developing a potentially inexpensive hollow Ce-ZnO/PANI sensor for sensing LPG efficiently.

Charge-Assisted Self-Assembly of ZIF-8 and Laponite Clay toward a Functional Hydrogel Nanocomposite.

The fabrication of a gel through the self-assembly of a nanoscale metal-organic framework is extremely rare. Here we report the facile synthesis of new hydrogel nanocomposites by the surface coating of ZIF-8 nanoparticles with laponite (LP) nanoclay through electrostatic interaction. The hydrogel exhibits a pH-controlled release of encapsulated guest molecules. Also, a luminescent hydrogel nanocomposite is prepared by encapsulating dye into ZIF-8, followed by gelation with LP.

Supramolecular Switching of Ion-Transport in Nanochannels.

Noncovalent approaches to achieve smart ion-transport regulation in artificial nanochannels have garnered significant interest in the recent years because of their advantages over conventional covalent routes. Herein, we demonstrate a simple and generic approach to control the surface charge in mesoporous silica nanochannels by employing π-electron-rich charged motifs (pyranine-based donors) to interact with the surface of mesoporous silica modified with π-electron-deficient motifs (viologen-based acceptors) through a range of noncovalent forces, namely, charge-transfer, electrostatic, and hydrophobic interactions. The extent of each of these interactions was independently controlled by molecular design and pH, while employing them in a synergistic or antagonistic fashion to modulate the binding affinity of the charged motifs. This enabled the precise control of the surface charge of the nanochannels to achieve multiple ion-transport states.

Encapsulation of Silver Nanoparticles in an Amine-Functionalized Porphyrin Metal-Organic Framework and Its Use as a Heterogeneous Catalyst for CO2 Fixation under Atmospheric Pressure.

A new porphyrin-based compound, [Zn3 (C40 H24 N8 )(C20 H8 N2 O4 )2 (DEF)2 ](DEF)3 (1; DEF=N,N-diethylformamide), has been synthesized by employing 5,10,15,20-tetrakis(4-pyridyl)porphyrin, 1,2-diamino-3,6-bis(4-carboxyphenyl)benzene, and Zn2+ salt at 100 °C under solvothermal conditions. The structure, as determined by single-crystal XRD studies, is three-dimensional with threefold interpenetration. The usefulness of free -NH2 groups in the ligand was exploited for anchoring silver nanoparticles through a simple solution-based route. The silver-loaded sample, Ag@1, was characterized by powder XRD, energy-dispersive X-ray spectroscopy, high-resolution TEM, SEM, X-ray photoelectron spectroscopy, and inductively coupled plasma MS analysis, which clearly indicated that silver nanoparticles with a size of 3.83 nm were uniformly distributed within the metal-organic framework (MOF). The Ag@1 sample was evaluated for possible catalytic activity for the carboxylation of a terminal alkyne by employing CO2 under atmospheric pressure; this gave excellent results. The Ag@1 catalyst was found to be robust, active, and recyclable. The present studies suggest that porphyrin MOFs not only exhibit interesting structures, but also show good heterogeneous catalytic activity towards the fixation of CO2 .

Comparative in vivo toxicity assessment places multiwalled carbon nanotubes at a higher level than mesoporous silica nanoparticles.

In the present work, we took two nanomaterials (NMs), mesoporous silica nanoparticles (MSNs) and multiwalled carbon nanotubes (MWCNTs), and compared their in vivo toxicity taking albino mice as a test animal model. Presently, conflicting data persist regarding behavior of these NMs with macromolecules like protein and lipid at the cellular level in cell lines as well as in animal models and this generated the interest to study them. The mice were treated orally with a single dose of 50 ppm MWCNTs and intraperitoneally with 10, 25, and 50 mg kg-1 body weight (BW) of MSNs and 1.5, 2.0, and 2.5 mg kg-1 BW of MWCNTs. Liver enzyme markers serum aspartate aminotransferase (AST), alanine aminotransferase, and alkaline phosphatase along with total protein (TP) levels were evaluated 7 days postexposure. No significant differences in organ weight indices or enzyme levels were observed between different treatment doses but there were significant differences between the treatment groups and the controls. Of the three enzymes assayed, AST displayed a peculiar pattern, especially in the MWCNTs intraperitoneally treated group. TP level was significantly increased in the orally treated MWCNTs group. The results showed that MWCNTs even at much smaller doses than MSNs displayed similar toxicity levels, suggesting that toxicity of MWCNTs is greater than MSNs.

A pharmacological overview of lamotrigine for the treatment of epilepsy.

INTRODUCTION: Epilepsy is one of the most common neurological disorders, affecting about 2% of the population worldwide. Lamotrigine (LTG) is a second generation anti-epileptic drug (AED) with broad spectrum of activity, a favourable side-effect profile, simpler dosing than earlier drugs and efficacious in diverse epilepsy syndromes. Areas covered: The present review focuses on pharmacodynamics, pharmacokinetics, clinical efficacy, safety and tolerability of LTG and its effect on cognition, psychiatry, quality of life, women and pregnancy along with effect of enzyme inducing and enzyme inhibiting drugs over LTG and their effect on serum level fluctuations by collecting data from various studies over the years until 2016. Expert commentary: Results from various studies and clinical trials indicate that LTG possessed a favourable profile of anticonvulsant activity and good tolerability as a monotherapy/or add-on therapy in children and adult patients against several types of seizures and syndromes. It has wide clinical dose range with favourable pharmacokinetic properties making it an excellent therapeutic option in epilepsy.

Reversible control of pore size and surface chemistry of mesoporous silica through dynamic covalent chemistry: philicity mediated catalysis.

Here, we report the synthesis of adaptive hybrid mesoporous silica having the ability to reconfigure its pore properties such as pore size and philicity in response to the external environment. Decyl chains were reversibly appended to the pore walls of silica through imine motifs as dynamic covalent modules to switch the pore size and philicity in response to pH. This switching of pore properties was used to gate the access of reactants to the gold nanoparticles immobilized inside the nanopores, thus enabling us to turn-on/turn-off the catalytic reaction. The use of such dynamic covalent modules to govern pore properties would enable the realization of intelligent hybrids capable of controlling many such chemical processes in response to stimuli.

Glucose- and pH-responsive charge-reversal surfaces.

We have shown a pH- and glucose-responsive charge reversal on silica surface through heterogeneous functionalization utilizing amines and boronic acid moieties. The dual responsiveness of the charge reversal has been unambiguously demonstrated through the desorption of charged chromophores. Interestingly, we observed a concentration-dependent desorption response to glucose at physiologically relevant levels.

Adaptive pores: charge transfer modules as supramolecular handles for reversible pore engineering of mesoporous silica.

We introduce a non-covalent pore engineering approach to achieve exceptional reversibility of functionalization in SBA-15 through viologen-pyranine charge transfer (CT) modules. By employing alkyl derivatives of pyranine as donors, we could exploit the strong CT interactions between pyranine and viologen to reversibly modify the pore size and philicity. The fast binding of the donors enables quick and facile functionalization within minutes at room temperature. The modularity of the approach enables modification of pores with custom-designed compositions, components, and functions. The high selectivity exhibited by viologen on the pore wall facilitated its use in a CT affinity column.

Aminoclay-supported copper nanoparticles for 1,3-dipolar cycloaddition of azides with alkynes via click chemistry.

Aminoclay supported copper nanoparticles are effective in promoting [3+2] cycloaddition of azides with terminal alkynes to produce the corresponding 1,2,3-triazoles in excellent yields. The copper nanoparticles are highly reactive in water and can be recycled for four cycles with consistent activity.

Amphiphilic aminoclay-RGO hybrids: a simple strategy to disperse a high concentration of RGO in water.

The aqueous dispersion of graphene or reduced graphene oxide (RGO) is very much important to realize the full potential of these materials in many fields. Herein we present a simple route to prepare highly water dispersible aminoclay-RGO (AC-RGO) hybrids by the in situ condensation of aminoclay over graphene oxide (GO) followed by reduction with hydrazine hydrate. The resultant hybrids are stable in aqueous media even at concentrations up to 7.5 mg RGO per mL. To the best of our knowledge this is the highest concentration of an aqueous dispersion of RGO. Significantly, the hybrids are amphiphilic in nature and show simultaneous adsorption of Cytochrome C through hydrophobic interaction and DNA through electrostatic interaction. This strategy opens up new possibilities for the prospect of RGO in catalysis and biomedical applications.

Histone acetylation as a therapeutic target.

The recent developments in the field of epigenetics have changed the way the covalent modifications were perceived from mere chemical tags to important biological recruiting platforms as well as decisive factors in the process of transcriptional regulation and gene expression. Over the years, the parallel investigations in the area of epigenetics and disease have also shown the significance of the epigenetic modifications as important regulatory nodes that exhibit dysfunction in disease states. In the present scenario where epigenetic therapy is also being considered at par with the conventional therapeutic strategies, this article reviews the role of histone acetylation as an epigenetic mark involved in different biological processes associated with normal as well as abnormal gene expression states, modulation of this acetylation by small molecules and warrants the possibility of acetylation as a therapeutic target.

Pd-aminoclay nanocomposite as an efficient recyclable catalyst for hydrogenation and Suzuki cross coupling reactions.

A highly water dispersible Pd-aminoclay nanocomposite is found to be effective catalytic system for the hydrogenation of alpha,beta-unsaturated carbonyl compounds and Suzuki coupling reactions in aqueous media. The catalytic hydrogenation of alpha,beta-unsaturated carbonyl compounds proceeds at room temperature to afford the corresponding products in excellent yields with high chemoselectivity. The cross coupling of aryl bromides and iodides with aryl boronic acids proceeds efficiently under aqueous conditions at 90 degrees C to afford the corresponding biaryls in excellent yields with high selectivity. The Suzuki reaction proceeds smoothly even in the absence of external base due to the basic nature of the catalyst support. The catalyst could be easily recovered and recycled three times without a significant loss of activity in hydrogenation and Suzuki cross coupling reactions.

Improved oxygen reduction reaction catalyzed by Pt/Clay/Nafion nanocomposite for PEM fuel cells.

A novel Pt nanoparticle (Pt NP) embedded aminoclay/Nafion (Pt/AC/N) nanocomposite catalyst film was prepared for oxygen reduction reaction by sol-gel method. The prepared nanocomposite films were surface characterized using XRD and TEM and thermal stability was studied by TGA. The prepared film has firmly bound Pt NP and could exhibit an improved electro-reduction activity compared to vulcan carbon/Nafion supported Pt NP (Pt/VC/N). Moreover, the Pt/AC/N film possessed good stability in the acidic environment. The limiting current density of the Pt/AC/N film with 35.4 µg/cm(2) of Pt loading was found to be 4.2 mA/cm(2), which is 30% higher than that of the Pt/VC/N. The maximum H2O2 intermediate formation was found to be ∼1.6% and the reaction found to follow a four electron transfer mechanism. Accelerated durability test for 2000 potential cycles showed that ca. 78% of initial limiting current was retained. The results are encouraging for possible use of the Pt/AC/N as the free-standing electrocatalyst layer for polymer electrolyte membrane fuel cells.

Aminoclay: a permselective matrix to stabilize copper nanoparticles.

Air sensitive copper nanoparticles have been stabilized using a water soluble aminoclay matrix. The aminoclay shows remarkable permselective behaviour allowing only the ionic species to diffuse through it and react with copper nanoparticles. It blocks the neutral molecule oxygen, thereby stabilizing the copper nanoparticles against oxidation for a longer period.

Aminoclay: a designer filler for the synthesis of highly ductile polymer-nanocomposite film.

Water-dispersible aminoclay synthesized in a single step process was used as an inorganic filler for preparing polyvinyl alcohol (PVA)-clay hybrid films. The PVA-clay hybrid films with different weight percentages of aminoclay were obtained by simple mixing and casting of aqueous solutions of clay and polymer. The composite films show excellent retention of ductile behavior of the polymer, PVA, even at higher loadings (20 wt %) of aminoclay. Introduction of aminoclay stabilized Ag nanoparticles significantly improved the mechanical properties of the composite film. The oxygen barrier property of the composite film was improved with the increase in composition of the clay.

Intrinsically fluorescent carbon nanospheres as a nuclear targeting vector: delivery of membrane-impermeable molecule to modulate gene expression in vivo.

In this report, we demonstrate glucose-derived carbon nanospheres to be an emerging class of intracellular carriers. The surfaces of these spheres are highly functionalized and do not need any further modification. Besides, the intrinsic fluorescence property of carbon nanospheres helps in tracking their cellular localization without any additional fluorescent tags. The spheres are found to target the nucleus of the mammalian cells, causing no toxicity. Interestingly, the in vivo experiments show that these nanospheres have an important ability to cross the blood-brain barrier and localize in the brain besides getting localized in the liver and the spleen. There is also evidence to show that they are continuously being removed from these tissues over time. Furthermore, these nanospheres were used as a carrier for the membrane-impermeable molecule CTPB (N-(4-chloro-3-trifluoromethylphenyl)-2-ethoxybenzamide), the only known small-molecule activator of histone acetyltransferase (HAT) p300. Biochemical analyses such as Western blotting, immunohistochemistry, and gene expression analysis show the induction of the hyperacetylation of histone acetyltransferase (HAT) p300 (autoacetylation) as well as histones both in vitro and in vivo and the activation of HAT-dependent transcription upon CTPB delivery. These results establish an alternative path for the activation of gene expression mediated by the induction of HAT activity instead of histone deacetylase (HDAC) inhibition.