Synthesis,characterization and in vitro DNA binding studies of a new copper(II) complex containing antioxidant ferulic acid

A mononuclear Cu(II) complex, [Cu(FA)₂(NO₃)₂], in which FA is ferulic acid ((E)-3-(4-hydroxy-3-methoxy-phenyl)prop-2-enoic acid), was synthesized and characterized by spectroscopic methods. The main structures of the ligand and its complexes with Cu²⁺ were optimized by QM calculations. The calculations on the structures of the [Cu(FA)₂(NO₃)₂] complexes forms and the intercalating with DNA profile were undertaken by UHF/PM6 and MMFF94 methods, respectively. In vitro studies (UV-vis spectroscopy, emission titration, circular dichroism techniques, and viscometry) under physiological conditions (Tris-HCl buffer solutions, pH 7.4) showed that the complex interacts with calf-thymus DNA (ct-DNA) via an intercalative binding mode. The thermodynamic parameters, enthalpy change (ΔH), and entropy change (ΔS) showed that the acting forces between Cu(II) complex and ct-DNA mainly included van der Waals interactions and hydrogen bonds. Methylene blue (MB) displacement studies revealed that Cu(II) complex can substitute MB probe in the MB-DNA complex which was indicative of intercalative binding. The theoretical data confirm the experimental results with respect to the mechanism of binding.     

Impact of modified electrodes on boosting power density of microbial fuel cell for effective domestic wastewater treatment:A case study of Tehran

Utilizing microbial fuel cells (MFCs) is a promising technology for energy-efficient domestic wastewater treatment, but it still faces practical barriers such as low power generation. In this study, the LaMnO₃ perovskite-type oxide nanoparticles and nickel oxide/carbon nanotube/polyaniline (NCP) nanocomposite (the cathode and anode catalysts, respectively) have been prepared and used to enhance power density of MFC. The prepared La-based perovskite oxide catalysts were characterized by X-ray diffraction (XRD) and scanning electron microscopies (SEM). The electrocatalytic properties of the prepared catalysts were investigated through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) and Tafel plot at ambient temperature. Results show the exchange current densities of LaMnO₃/carbon cloth cathode and NCP nanocomposite/carbon cloth anode were 1.68 and 7 times more compared to carbon cloth cathode, respectively. In comparison to the bare carbon cloth anode, the MFC with the modified electrodes shows 11 times more enhancement in power density output which according to electrochemical results, it can be due to the enhancement of the electron transfer capability. These cathodic and anodic catalysts were examined in batch and semi-continuous modes to provide conditions close to industrial conditions. This study suggests that utilizing these low cost catalysts has promising potential for wastewater treatment in MFC with high power generation and good COD removal efficiency.     

A Review on Cs-Based Pb-Free Double Halide Perovskites: From Theoretical and Experimental Studies to Doping and Applications

Despite the progressive enhancement in the flexibility of Pb-based perovskites for optoelectronic applications, regrettably, they are facing two main challenges; (1) instability, which originates from using organic components in the perovskite structure, and (2) toxicity due to Pb. Therefore, new, stable non-toxic perovskite materials are demanded to overcome these drawbacks. The research community has been working on a wide variety of Pb-free perovskites with different molecular formulas and dimensionality. A variety of Pb-free halide double perovskites have been widely explored by different research groups in search for stable, non-toxic double perovskite material. Especially, Cs-based Pb-free halide double perovskite has been in focus recently. Herein, we present a review of theoretical and experimental research on Cs-based Pb-free double halide perovskites of structural formulas Cs₂M⁺M³⁺X6 (M⁺ = Ag⁺, Na⁺, In⁺ etc.; M³⁺= Bi³⁺, In³⁺, Sb³⁺; X = Cl⁻, Br⁻, I¯) and Cs₂M⁴⁺X₆ (M⁴⁺ = Ti⁴⁺, Sn⁴⁺, Au⁴⁺ etc.). We also present the challenges faced by these perovskite compounds and their current applications especially in photovoltaics alongside the effect of metal dopants on their performance.     

Label-free and sensitive impedimetric nanosensor for the detection of cocaine based on a supramolecular complexation with β-cyclodextrin,immobilized on a nanostructured polymer film

Cocaine, a powerful addictive stimulant drug, has a variety of adverse effects on the body, thus its sensitive detection is very important. Here, we report on a simple, label-free, and sensitive impedimetric sensor for determination of cocaine based on its affinity to form an inclusion complex with β-cyclodextrin (β-CD). First, we prepared nanostructured poly N-acetylaniline film via electropolymerization of its monomer on a glassy carbon electrode (PNAANI/GC), subsequently overoxidized it, and conjugated β-CD to the polymer backbone. The designed and synthesized nanostructured PNAANI film serves a dual function in the sensor: on one hand, it maintains a high effective surface area on a geometrically small electrode that significantly enhances the number of β-CD molecules immobilized on the electrode; on the other hand, it provides an upright-oriented β-CD conjugation to the polymer backbone, thus all the β-CD receptors are actively involved in responding to the target. Sensitivity of the sensor was further enhanced by preconcentration of cocaine on the modified electrode surface. We attributed the changes in the interfacial charge transfer resistance (R _ct) of the electrode to cocaine concentration. Under optimized condition (pH 7.4, 5-min accumulation at an open circuit voltage), the sensor responded to cocaine concentration in the range of 100 nM–1.0 mM with a detection limit of 50 nM. Selectivity of the sensor for cocaine relative to some potential inferring compounds was also investigated, and the results were promising. The proposed approach exhibited an extended dynamic range, low detection limit, good sensitivity, and a desirable selectivity, which provides an efficient application prospect for on-field cocaine sensing.     

Molecularly imprinted stir bar sorptive extraction coupled with high-performance liquid chromatography for trace analysis of naphthalene sulfonates in seawater

In this paper, a novel molecularly imprinted polymer coated stir bar has been used to selectively extract naphthalene sulfonates (NS_s) directly from seawater sample. 1-Naphthalene sulfonic acid (1-NS) was used as template molecule. The effects of different parameters were optimized on the extraction efficiency and the optimum conditions were established as: the absorption and desorption times were fixed, respectively, at 10 and 15 min, stirring speed was 700 rpm, pH was adjusted to 4.1, amount of NaCl was 1 mol L^?1 and extraction process was performed at a temperature of 50 °C. The linear ranges were 2–250 µg L^?1 for 3,6-NDS-1-OH (1-naphthol-3,6-disulfonic acid), 4–250 µg L^?1 for 2-NS (2-naphthalene sulfonate) and 3–250 µg L^?1 for 1-NS. The detection limits were within the range of 0.32–0.95 µg L^?1. Under optimum conditions, the detection limits of the NSs were 0.84, 0.95 and 0.32 µg L^?1 with the enrichment factor of 117-, 41- and 77-fold for 2-NS, 1-NS, and 6-NDS-1-OH, respectively. The repeatability of the method was satisfactory (0.53 ≤ RSD ≤6.0 %, n = 10). The method has been successfully applied for the analysis of trace amounts of three naphthalene sulfonates in seawater of Chabahar Bay.     

Characterization of the interaction between a new merocyanine dye and bovine serum albumin

A new merocyanine dye was synthesized, and its acidity constant was determined by spectrophotometric and chemometrics methods. The interactions of the new cyanine dye with bovine serum albumin (BSA) have been studied by fluorescence and UV absorption spectroscopy at pH 7.40. A visual color change from red to blue was observed by addition of BSA to aqueous solution of the dye. The quenching constants and binding parameters (binding constants and number of binding sites) were determined at different temperatures. The calculated thermodynamic parameters confirmed that the binding reaction is mainly entropy-driven, whereas electrostatic interaction plays major role in the reaction. The displacement experiment confirmed binding of the dye to the subdomain IIA (site 1) of albumin. Moreover, synchronous fluorescence spectroscopy studies revealed the dye induces some local conformational change in BSA. The binding distance, r, between donor (serum albumin) and acceptor (dye) was obtained according to Förster’s theory.     

Exploration of the binding properties of the human serum albumin sites with neurology drugs by docking and molecular dynamics simulation

In this study, the binding properties of a set of neurology drugs to human serum albumin (HSA) were studied by docking and molecular dynamic (MD) methods. Based on the RMSD values for the MD simulation processes, the drug–protein complexes are stable. Site II of the HSA shows the best affinity for the studied drugs. Different kinds of interactions, including hydrogen bonding, π-cation interactions, and π–π interactions, are observable between ligand and protein during the MD simulation process. The MMGBSA calculations were done to evaluate the binding energy of the ligands and protein. The calculated energies are in good agreement with the previously reported experimental results. In some cases, there is a direct relation between the calculated binding energy with the half-life of the drugs, as it was expected.     

The first principle computational study for the competitive mechanisms of oxidative aromatization of 2-substituted imidazolines using KMnO<Subscript>4</Subscript>/SiO<Subscript>2</Subscript>

The efficiently oxidized various types of 2-substituted imidazolines to the corresponding imidazoles using potassium permanganate supported on silica gel (KMnO₄/SiO₂) under mild conditions and at room temperature have been reported before. In this study, the competitive concerted, catalytic stepwise (E ₁ cb′ _Cat .) and E ₁ cb′ mechanisms of the oxidative aromatization process of 2-imidazolines to the corresponding imidazoles using KMnO₄/SiO₂ have been theoretically investigated by DFT-B3LYP/6-31G** method. The achieved data from this computational study confirmed that the reaction occurs by stepwise E ₁ cb′ mechanism on the basis of the anomeric effect.