Electrocatalytic Determination of Ascorbic Acid Using a Palladium Coated Nanoporous Gold Film Electrode

Cyclic voltammetry and differential pulse voltammetry were used to investigate the electrochemical behavior of ascorbic acid (AA) on palladium coated nanoporous gold film (PdNPGF) electrode. The deposition of palladium was done through oxidation of copper UPD layer by palladium ions. This low Pd‐loading electrode behaved as the nanostructured Pd for electrocatalytic reaction. The PdNPGF electrode exhibits excellent electrocatalytic behavior by enhancing the AA oxidation peak current due to synergistic influence of the Pd film and NPGF. The kinetic parameters such as electron transfer coefficient, α, was 0.47 and the voltammetric responses of the PdNPGF electrode were linear against concentration of AA in the ranges of 2.50–33.75 mM and 0.10–0.50 mM with CV and DPV respectively.     

Recent Progress in Polyaniline and its Composites for Supercapacitors

Polyaniline (PANI) has piqued the interest of nanotechnology researchers due to its potential as an electrode material for supercapacitors. Despite its ease of synthesis and ability to be doped with a wide range of materials, PANI′s poor mechanical properties have limited its use in practical applications. To address this issue, researchers investigated using PANI composites with materials with highly specific surface areas, active sites, porous architectures, and high conductivity. The resulting composite materials have improved energy storage performance, making them promising electrode materials for supercapacitors. Here, we provide an overview of recent developments in PANI-based supercapacitors, focusing on using electrochemically active carbon and redox-active materials as composites. We discuss challenges and opportunities of synthesizing PANI-based composites for supercapacitor applications. Furthermore, we provide theoretical insights into the electrical properties of PANI composites and their potential as active electrode materials. The need for this review stems from the growing interest in PANI-based composites to improve supercapacitor performance. By examining recent progress in this field, we provide a comprehensive overview of the current state-of-the-art and potential of PANI-based composites for supercapacitor applications. This review adds value by highlighting challenges and opportunities associated with synthesizing and utilizing PANI-based composites, thereby guiding future research directions.     

Photocatalytic degradation of carcinogenic Congo red dye in aqueous solution,antioxidant activity and bactericidal effect of NiO nanoparticles

Journal of the Iranian Chemical Society - Face-centered cubic structure of nickel oxide (NiO) nanoparticles with 30 nm average size was synthesized by co-precipitation method with some...     

Fabrication of inorganic alumina particles at nanoscale by a pulsed laser ablation technique in liquid and exploring their protein binding,anticancer and antipathogenic activities

The interaction of nanoparticles with biological systems can provide useful information about their therapeutic applications. The aluminum nanoparticles (Al₂O₃ NPs) were synthesized by laser ablation technique and well-characterized by different methods. Fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and molecular docking studies were employed to evaluate the effect of Al₂O₃ NPs on the protein structure. Growth inhibitory and apoptotic effects of the Al₂O₃ NPs against K562 cancer cells and lymphocyte cells were assessed using [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] (MTT), flow cytometry, and real time polymerase chain reaction (PCR) assays. The antipathogenic activity of Al₂O₃ NPs against a diverse range of Gram-negative and Gram-positive pathogens was explored through a disk diffusion method. The characterization techniques determined that the Al₂O₃ NPs were successfully synthesized in the nanoscales. Intrinsic, 1-anilino-8-naphthalenesulfonate (ANS) and acrylamide fluorescence spectroscopy studies disclosed that Al₂O₃ NPs can partially change the tertiary structure of human serum albumin (HSA), whereas CD spectroscopy investigation depicted that the secondary structure of HSA remained intact. Molecular docking investigation also manifest that the Al₂O₃ nano-clusters preferably bind to electrostatic residues. Al₂O₃ NPs exhibited promising and selective anticancer features through reactive oxygen species (ROS) production, apoptosis induction, and elevation of Bax/Bcl-2 mRNA ratio. Furthermore, the Al₂O₃ NP showed a remarkable antibacterial activity against both Gram-negative and Gram-positive pathogens. In conclusion, it may be suggested that the synthesized Al₂O₃ NPs can be integrated in the development of anticancer and antipathogenic agents.     

Direct introduction of amine groups into cellulosic paper for covalent immobilization of tyrosinase: support characterization and enzyme properties

Tyrosinase is used to eliminate phenolic compounds from wastewater. Therefore, its immobilization is important to enhance catalytic efficiency. Papery materials are of particular interest for use as support for enzyme immobilization since the porous microstructure of fiber networks in papers can provide a suitable reaction environment, especially in flow-type catalytic reactions. However, immobilization of protein onto papery structure needs chemical modifications in severe conditions. To overcome this challenge, a cellulosic paper was directly amine-functionalized in moderate conditions and used for tyrosinase immobilization. The support was pretreated with HCl (0.5 N) solution and then sequentially immersed in ethylenediamine (EDA), glutaraldehyde solution (2% v/v) and the crude enzyme. In comparison with the untreated one, the immobilized enzyme on the EDA-treated support offered a 3.7-fold increase in activity. The FTIR spectra as well as EDX analysis proved the presence of amine groups in the cellulosic paper and also covalent immobilization of tyrosinase on the modified support. When considering the effect of pH on the activity at 25 °C, a maximum relative activity of 134% at pH 6 was revealed. Similarly, evaluating the effect of temperature on the activity at pH 7 displayed a maximum relative activity of 152% at 35 °C. The immobilized enzyme was suitable for use for more than four cycles to degrade a phenolic compound at severe pH and temperature conditions. Additionally, the immobilized enzyme was active after treatment of the surface at different pHs and temperatures for 105 min. The chemically modified cellulosic paper can be used as a support for enzyme immobilization.     

Synthesis,characterization and in vitro DNA binding studies of a new copper(II) complex containing an antiviral drug,valganciclovir

A new complex, [Cu(valcyte)₂(NO₃)₂], in which valcyte served as a valganciclovir drug, was synthesized and characterized by different physicochemical methods. Optimization of ligand structures and their complexes with Cu²⁺ were performed by semi-empirical and DFT methods. Binding interaction of this complex with calf-thymus DNA (ct-DNA) was explored by emission, absorption, circular dichroism and viscosity techniques. Additionally, cell line targeting was studied and cytotoxic effects of [Cu(valcyte)₂(NO₃)₂] (0.0–160 μg) on AGS and MCF-7 cell lines were reported. Percentage of Cell Viability and Apoptotic Index were assessed. The complex displayed significant binding properties to ct-DNA. Undertaking fluorometric studies, the binding mode of the complex with ct-DNA was explored utilizing Hoechst as a fluorescence probe, indicating the binding to be of groove mode. The DNA viscosity altered slightly in presence of the complex. Enthalpy and entropy changes during the interaction showed that the process is endothermic, with the complex mainly bound to ct-DNA by hydrophobic attraction. Values of ΔG revealed a spontaneous reaction between DNA and the complex. Optimized docked model of DNA–complex mixture confirmed the experimental results. The results of MMFF94 calculations indicated stability of [Cu(valcyte)₂(NO₃)₂] after docking with the modeled DNA profile, as compared to the DNA profile and valganciclovir results before the docking process. Cytotoxicity studies showed that an increase in [Cu(valcyte)₂(NO₃)₂] may result in a significant decrease in cell viability and increase apoptosis index in the treated cells, as compared to valganciclovir treated cells (p < 0.05). The findings further showed that [Cu(valcyte)₂(NO₃)₂] has potential for use in cancer therapy.     

Synthesis,structural determination and HSA interaction studies of a new water-soluble Cu(II) complex derived from 1,10-phenanthroline and ranitidine drug

A new water-soluble Cu(II) complex containing ranitidine drug and 1,10-phenanthroline was synthesized and characterized by elemental analysis, molar conductivity, spectroscopic and computational methods. In vitro human serum albumin (HSA)-interaction studies of Cu(II) complex were performed by employing fluorescence spectroscopy in combination with UV–vis absorption and circular dichroism (CD) spectroscopies. The results of fluorescence titration showed that Cu(II) complex strongly quenched the intrinsic fluorescence of HSA through a static quenching mechanism with an intrinsic binding constant (6.05 × 10⁴ M^?1) at 286 K. The thermodynamic parameters ΔG, ΔH, and ΔS at different temperatures were calculated and suggested that the hydrophobic and hydrogen bonding interactions play major roles in Cu(II) complex-HSA association. The displacement experiments using warfarin and ibuprofen as site I and II probes proved that the Cu(II) complex could bind to site I (subdomain IIA) of HSA. Finally, CD spectra indicated that the interaction of the Cu(II) complex with HSA leads to an increase in the α-helical content. The main result of this study was the finding that the binding affinity of the Cu(II) complex to HSA is three orders of magnitude stronger than that of ranitidine drug.     

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.