Impact of temperature on the binding interaction between dsDNA and curcumin: An electrochemical study.

In this study, we investigated the binding mode between double-stranded deoxyribonucleic acid (dsDNA) and curcumin (CU) using differential pulse voltammetry (DPV), UV-Vis spectroscopy, and molecular docking. By employing these techniques, we predicted the binding within the minor groove region of dsDNA and CU. Significantly, we employed electrochemistry, specifically cyclic voltammetry (CV), to explore the temperature effect on the dsDNA and CU binding. To the best of our knowledge, this is the first study to utilize electrochemical methods for investigating the temperature-dependent behavior of this binding interaction. Our findings revealed temperature-dependent variations in the binding constants: 2.42 × 103 M-1 at 25 °C, 4.26 × 103 M-1 at 30 °C, 5.44 × 103 M-1 at 35 °C, 6.29 × 103 M-1 at 40 °C, and 7.52 × 103 M-1 at 45 °C. Notably, the binding constant exhibited an increasing trend with elevated temperatures, indicating a temperature-dependent enhancement of the binding interaction.

Nanocore-Shell Bone Filler Contained Mesoporous Silica Modified with Hydroxyapatite Precursors; Wrapped in a Natural Metal-Phenolic Network.

Various therapeutic strategies have been developed to address bone diseases caused by aging society and skeletal defects caused by trauma or accidental events. One such approach is using bone fillers, such as hydroxyapatite (HA) and bioactive glasses. Although they have provided effective osteogenesis, infection and inflammation due to the surgical procedure and uncontrolled ion release can hinder the efficiency of bone regeneration. In response to these challenges, immobilizing a neutral metal-phenolic network on the surface of osteoconductive nanoparticles would be the master key to achieving a gradual, controlled release during the mineralization period and reducing infection and inflammation through biological pathways. In this regard, a mesoporous silica nanocomposite modified by an HA precursor was synthesized to enhance bone regeneration. In addition, to improve the therapeutic effects, its surface was wrapped with a magnesium-phenolic network made from pomegranate extract, which can simultaneously produce anti-inflammatory and antibacterial effects. The obtained core-shell nanocomposite was characterized by its physicochemical properties, biocompatibility, and bioactivity. The in vitro studies revealed that the synthesized nanocomposite exhibits higher osteogenic activity than the control groups, as confirmed by alizarin red staining. Moreover, the nanocomposite maintained low toxicity as measured by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and increased antibacterial activity against Staphylococcus aureus and Escherichia coli compared with the control groups. Therefore, this research presents a promising strategy for bone regeneration, combining the advantages of mesoporous silica nanocomposite modified by an HA precursor with the beneficial effects of a magnesium-phenolic network.

A curcumin-nicotinoyl derivative and its transition metal complexes: synthesis, characterization, and in silico and in vitro biological behaviors.

Curcumin-nicotinoyl (Cur-Nic) was synthesized by the chemical modification of the curcumin structure, characterized, and used as a ligand for the synthesis of copper(II) and zinc(II) complexes. The biological activities of Cur-Nic and its metal complexes were predicted using the PASS and Swiss Target Prediction online software, respectively, and docking studies with tyrosine-protein kinase SRC were performed using the PyRx software to predict their anticancer activities. The toxicity effects of the complexes on a human breast cancer cell line (MCF-7) compared to a healthy breast cell line (MCF-10A) were investigated by the MTS assay. Although the metal complexes maintained the least toxicity against normal cells, the results indicated that compared to curcumin and Cur-Nic, the cytotoxicity toward cancer cells increased due to the complexation process. Moreover, the antibacterial evaluation of the compounds against a Gram-positive bacterium (MRSA) and a Gram-negative bacterium (E. coli) indicated that the Cu(II) complex and Cur-Nic were the best, respectively. Also, the Zn(II) complex was the most stable compound, and the Cu(II) complex was the best ROS scavenger based on the in vitro evaluation.

A combined experimental and theoretical study of RuO2/TiO2 heterostructures as a photoelectrocatalyst for hydrogen evolution.

We report a joint experimental and theoretical study of RuO2/TiO2 heterostructures. In the experimental section, mesoporous RuO2/TiO2 heterostructures were prepared by impregnation of mesoporous TiO2 nanoparticles which were synthesized from a new precursor, Na2[Ti(C2O4)3], in an aqueous solution of ruthenium(III) chloride followed by calcination at 300 °C. Using various techniques, the prepared TiO2 and RuO2/TiO2 heterostructures were extensively characterized. The photoelectocatalytic application of the as-prepared heterostructures was then investigated toward the hydrogen evolution reaction (HER). The results illustrated that RuO2 is dispersed uniformly on the TiO2 surface. The loading of RuO2 on TiO2 decreases the band gap energy and extends the absorption edge to the visible light region. This wide absorption extends the photoelectrocatalytic activity of RuO2/TiO2 heterostructures. To obtain a deeper understanding of the increase of the photoelectrocatalytic activity of RuO2/TiO2 heterostructures compared to pure TiO2, theoretical calculations at the density functional theory (DFT) level were performed on some model clusters of pure TiO2 and the RuO2/TiO2 heterostructure. The theoretical results elucidated that the recombination ratio of electron-hole pairs decreases effectively for RuO2/TiO2 compared to pure TiO2.

[Ru(tmphen)3]2[Fe(CN)6] and [Ru(phen)3][Fe(CN)5(NO)] complexes and formation of a heterostructured RuO2-Fe2O3 nanocomposite as an efficient alkaline HER and OER electrocatalyst.

Water electrolysis is one of the most capable processes for supplying clean fuel. Herein, two novel ionic Ru(II)-Fe(II) complexes, [Ru(tmphen)3]2[Fe(CN)6] and [Ru(phen)3][Fe(CN)5(NO)], where tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline and phen = 1,10-phenanthroline, were synthesized and characterized by UV-Vis spectroscopy, elemental analysis, FT-IR, and single-crystal X-ray structural analysis. By thermally decomposing the [Ru(tmphen)3]2[Fe(CN)6] complex at 600 °C for 4 h, a heterostructured RuO2-Fe2O3 nanocomposite was fabricated through a facile one-pot treatment and then characterized by FT-IR, XRD, FT-Raman, UV-Vis (DRS), ICP-OES, FE-SEM, TEM, TGA/DTG, BET, and XPS analyses, which revealed the formation of highly crystalline RuO2-Fe2O3 nanoparticles with an average size of 8-12 nm. The prepared nanocomposite was an efficient heterostructured electrocatalyst for performing water-splitting redox reaction processes, including hydrogen and oxygen evolution reactions (HER and OER) in alkaline solutions. In this regard, RuO2 and Fe2O3 samples were also prepared through thermal decomposition of [Ru(tmphen)3](NO3)2 and K4[Fe(CN)6] precursors, respectively, as control experiments to compare their HER and OER electrocatalytic activity with that of the RuO2-Fe2O3 nanocomposite. Specifically, the RuO2-Fe2O3 nanocomposite exhibited significant electrocatalytic performance, generating 10 mA cm-2 current density at -148 and 292 mV overpotentials, and the Tafel slope results from fitting the LSV curves to the Tafel equation were -43 and 56.08 mV dec-1 for the HER and OER, respectively. Therefore, the heterostructured RuO2-Fe2O3 nanocomposite can be viewed as a bi-functional electrocatalyst for HER and OER because it exploits the synergistic effects of heterostructures and active sites at its interface.

Water-vapochromic behavior of a mononuclear Pd(II) complex of piroxicam: A DFT and TD-DFT study.

The vapochromic behavior of a mononuclear Pd(II) complex with piroxicam ligands (trans-[Pd(Pir)2] (Pir- is piroxicam anion)) in the presence of water vapor has been theoretically investigated using the time-dependent density functional theory (TD-DFT). The structure of Pd(II) complex interacting with different number of water molecules (n = 1-5) was optimized, separately. The electronic absorption spectra of the optimized structures were calculated using the TD-DFT method and the changes in the absorption spectrum of complex with the increase in the number of water molecules were followed. Comparison of the absorption spectrum of bare Pd(II) complex with those of its hydrated forms with different numbers of water molecules showed a considerable change in the region of 360-400 nm including the change in the intensity and peak position. The main electronic configurations of the intense absorption lines in the related absorption spectra were determined so that the molecular orbitals involved in these absorption lines were determined. The natural bonding orbital (NBO) analysis was performed to assign the NBOs contributing to these molecular orbitals and to see how the NBO composition of the involved molecular orbitals in the electron excitation change with the number of water molecules. It was observed that the change in the intensity and position of the inter- and intraligand π→π∗ transitions are responsible for the color change. Also, based on the NBO results, the contribution of the electronic transitions involving the Pd(II) ion in the color change of the complex was absent.

Aptamer/magnetic nanoparticles decorated with fluorescent gold nanoclusters for selective detection and collection of human promyelocytic leukemia (HL-60) cells from a mixture.

In the present work, a fluorescent gold nanoclusters (GNCs)/superparamagnetic (Fe3O4/GNCs) nanoprobe was prepared via a facile approach for the selective detection and imaging of human leukemica cancer cells (HL-60). (γ-Mercaptopropyl)trimethoxysilane (MPS) was used as a stabilizer to prepare functionalized GNCs. The prepared GNCs@MPS was then self-assembly decorated on the surface of Fe3O4@SiO2 nanoparticles followed by poly(ethylene glycol) dimethacrylate (PGD) addition at room temperature to form Fe3O4/GNCs nanoprobe. Surface functionalization of the Fe3O4/GNCs with the thiol-modified KH1C12 aptamer was done through thiol-en click reaction between PGD and the thiol group of the aptamer. An extensive characterization of the Fe3O4/GNCs revealed strong red fluorescence (λ em = 627 nm), T 2-based contrast agent for MRI and excellent colloidal and photo stability in buffer medium. So, the aptamer-functionalized Fe3O4/GNCs nanoprobe (Fe3O4/GNCs/Aptamer) is capable to uptake and dual-image HL-60 cancer cells from a mixture. Furthermore, the MRI signal intensity of the pictures decreased linearly with an increase in the concentrations of the nanoprobe. It is also enable to detect cancer cells from a range of concentrations 10 up to 200 cells µL-1. The fluorescent/magnetic characteristics of the nanoprobe are of great significance for MRI-based and fluorescence imaging and collection of HL-60 cancer cells which implies potential help for the development of early diagnosis of highly malignant human leukemia.

Design and Synthesis of Gatekeeper Coated Dendritic Silica/Titania Mesoporous Nanoparticles with Sustained and Controlled Drug Release Properties for Targeted Synergetic Chemo-Sonodynamic Therapy.

New dendritic silica/titania mesoporous nanoparticles (DSTNs) loaded with curcumin (CUR) were synthesized and coated with polyethylenimine-folic acid groups (PEI-FA) for an ultrasound (US)-triggered drug release and combined chemo-sonodynamic therapy. The PEI-FA groups play a gatekeeper role, strongly encapsulate the CUR molecules inside the nanocarrier, and prevent the unwanted premature release by blocking the mesoporous channels. The results showed that the specific cancer cell uptake is improved by FA groups on the surfaces of DSTNs via receptor-mediated endocytosis. The TiO2 layer as a sonosensitizer agent coated on the mesoporous silica nanoparticles generates reactive oxygen species. Following the US irradiation, the PEI molecules were cut off by free radicals, including OH· and O2-, on the exterior surface of DSTNs, and the CUR loaded in the nanocarrier was then released into the cancer cell cytosol. The release profiles of the CUR@PEI-FA-DSTN system showed that the amount of CUR released from DSTNs is controlled by tuning the US radiation time. The results of the MTT cytotoxicity tests of free CUR, free PEI-FA-DSTN nanocarrier, and CUR@PEI-FA-DSTNs against A549 (human lung carcinoma cell lines) and HeLa (human cervical carcinoma cell lines ( showed that the toxicity of CUR@PEI-FA-DSTNs is higher than those of CUR and PEI-FA-DSTNs alone. In addition, the specific targeting ability, the cellular uptake, and the anticancer activity of the synthesized compounds for targeted cancer treatment were investigated using different staining methods and fluorescence microscopy. The results revealed that the new system, CUR@PEI-FA-DSTNs, can be considered as a potent drug delivery system for increasing effectiveness of the anticancer activity of curcumin in the combined chemo-sonodynamic therapy.

Immobilization of gold nanoparticles on folate-conjugated dendritic mesoporous silica-coated reduced graphene oxide nanosheets: a new nanoplatform for curcumin pH-controlled and targeted delivery.

In the present study, a new sandwich-like nanocomposite as a multifunctional smart nanocarrier for curcumin (Cur) targeted delivery and cell imaging was prepared by immobilization of gold nanoparticles on folic acid-modified dendritic mesoporous silica-coated reduced graphene oxide nanosheets (AuNPs@GFMS). The physical and chemical properties of the nanocomposite were investigated by atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-Vis, field-emission scanning electron microscopy (FE-SEM), Fourier transformation infrared (FT-IR), and Brunauer-Emmett-Teller (BET) surface area analysis. The nanocarrier exhibits a number of interesting properties, including good biocompatibility, biodegradability, and suitable surface area, which results in high drug loading capacity. In addition, this new drug delivery system showed sustained-release and pH-responsive properties. The in vitro cytotoxicity test of the free curcumin, free nanocarrier (AuNPs@GFMS), curcumin-loaded folate-conjugated nanocarriers (Cur-AuNPs@GFMS), and curcumin-loaded nanocarriers without folate-conjugation (Cur-AuNPs@GAMS) against two human cancer cell lines, including MCF-7 (human breast carcinoma cell lines) and A549 (human lung carcinoma cell lines) demonstrated that the therapeutic efficacy of Cur-AuNPs@GFMS is significantly greater than those of other compounds because the cancerous cells can uptake the folate-conjugated drug nanocarrier via a receptor-mediated mechanism. Fluorescence microscopic images and different staining techniques were also used to visualize the cellular uptake, anticancer activity, specific targeting ability, and photothermal potency of Cur-AuNPs@GFMS toward the MCF-7 cancer cells. The obtained results proved that the proposed system, Cur-AuNPs@GFMS, can be used as a potent anticancer agent in targeted cancer therapies for breast cancer.

Perrhenate-Catalyzed Deoxydehydration of a Vicinal Diol: A Comparative Density Functional Theory Study.

Oxo-rhenium compounds, such as perrhenate salts, have demonstrated preferable activity in catalyzing the deoxydehydration (DODH) reaction in the presence of reductants. Here, the first computational details of the reported DODH mechanisms are presented using the density functional theory (DFT) (M06/6-311+G(d,p)/LANL2DZ) to investigate the conversion of a vicinal diol into the corresponding alkene by ReO4- as a catalyst. The DFT studies were carried out to evaluate the DODH mechanisms, from the energy point of view, for the conversion of phenyl-1,2-ethanediol to styrene by perrhenate anion in the presence of PPh3 as a reductant through a detailed comparison of two potential pathways including pathway A and pathway B. Pathway A includes the sequence of condensation of oxo-Re(VII) with diol before the reduction of Re(VII) to Re(V), whereas pathway B involves the reduction of oxo-Re(VII) to oxo-Re(V) before the condensation process. In pathway B, two basic routes (B1 and B2) are possible, which can take place through different reaction steps, including the extrusion of alkene from Re(V)-diolate in route B1, and the second reduction of the Re(V)-diolate by reductant and then the extrusion of alkene from the Re(III)-diolate intermediate in route B2. The intermediates and the Gibbs free energy changes, including ΔG°g and ΔG°sol, have been calculated for alternative pathways (A and B) in the gas and solvent (chlorobenzene and methanol) phases and compared to each other. In addition, the transition states and the activation energy barriers for two pathways (A and B) in the gas phase and in chlorobenzene have been calculated. The key transition states include the nucleophilic attack of PPh3 on an Re═O bond, the dissociation of OPPh3 from the rhenium moiety, the transfer of an H atom of diol to the oxo ligand in an oxo-Re bond through the condensation step, and the extrusion of styrene from the Re-diolate complexes. The DFT results indicate that the DODH reaction is thermodynamically feasible through both pathways (A and B). However, the calculations reveal that the perrhenate-catalyzed DODH reaction through pathway A has the lowest overall activation barrier energy among the DODH mechanism routes.

Synthesis, structure, DNA/protein binding, and cytotoxic activity of a rhodium(III) complex with 2,6-bis(2-benzimidazolyl)pyridine.

A new mononuclear rhodium(III) complex, [Rh(bzimpy)Cl3] (bzimpy = 2,6-bis(2-benzimidazolyl)pyridine), was synthesized and characterized by elemental analysis and spectroscopic methods. The molecular structure of the complex was confirmed by single-crystal X-ray crystallography. The interaction of the complex with fish sperm DNA (FS-DNA) was investigated by UV spectroscopy, emission titration, and viscosity measurement in order to evaluate the possible DNA-binding mode and to calculate the corresponding DNA-binding constant. The results reveal that the Rh(III) complex interacts with DNA through groove binding mode with a binding affinity on the order of 104. In addition, the binding of the Rh(III) complex to bovine serum albumin (BSA) was monitored by UV-Vis and fluorescence emission spectroscopy at different temperatures. The mechanism of the complex interaction was found to be static quenching. The thermodynamic parameters (ΔH, ΔS, and ΔG) obtained from the fluorescence spectroscopy data show that van der Waals interactions and hydrogen bonds play a major role in the binding of the Rh(III) complex to BSA. For the comparison of the DNA- and BSA-binding affinities of the free bzimpy ligand with its Rh(III) complex, the absorbance titration and fluorescence quenching experiments of the free bzimpy ligand with DNA and BSA were carried out. Competitive experiments using eosin Y and ibuprofen as site markers indicated that the complex was mainly located in the hydrophobic cavity of site I of the protein. These experimental results were confirmed by the results of molecular docking. Finally, the in vitro cytotoxicity properties of the Rh(III) complex against the MCF-7, K562, and HT-29 cell lines were evaluated and compared with those of the free ligand (bzimpy). It was found that the complexation process improved the anticancer activity significantly.

Sensitive spectrophotometric determination of Co(II) using dispersive liquid-liquid micro-extraction method in soil samples.

Analytical performance of conventional spectrophotometer was developed by coupling of effective dispersive liquid-liquid micro-extraction method with spectrophotometric determination for ultra-trace determination of cobalt. The method was based on the formation of Co(II)-alpha-benzoin oxime complex and its extraction using a dispersive liquid-liquid micro-extraction technique. During the present work, several important variables such as pH, ligand concentration, amount and type of dispersive, and extracting solvent were optimized. It was found that the crucial factor for the Co(II)-alpha benzoin oxime complex formation is the pH of the alkaline alcoholic medium. Under the optimized condition, the calibration graph was linear in the ranges of 1.0-110 µg L(-1) with the detection limit (S/N = 3) of 0.5 µg L(-1). The preconcentration operation of 25 mL of sample gave enhancement factor of 75. The proposed method was applied for determination of Co(II) in soil samples.

A mononuclear Cu(II) complex with 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine: Synthesis, crystal structure, DNA- and BSA-binding, molecular modeling, and anticancer activity against MCF-7, A-549, and HT-29 cell lines.

The copper(II) complex of 1,2,4-triazine derivatives, [Cu(dppt)2(H2O)](PF6)2(dppt is 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine), has been synthesized and fully characterized by spectroscopic methods and single crystal X-ray diffraction. The in vitro DNA-binding studies of the complex have been investigated by several methods. The results showed that the complex intercalates into the base pairs of DNA. The complex also indicated good binding propensity to BSA. The results of molecular docking and molecular dynamic simulation methods confirm the experimental results. Finally, the in vitro cytotoxicity indicate that the complex has excellent anticancer activity against the three human carcinoma cell lines, MCF-7, A-549, and HT-29, with IC50 values of 9.8, 7.80, and 4.50 µM, respectively. The microscopic analyses of the cancer cells demonstrate that the Cu(II) complex apparently induced apoptosis.

Antiproliferative effects of copper(II)-polypyridyl complexes in breast cancer cells through inducing apoptosis.

Although cisplatin has been used for decades to treat human cancer, some toxic side effects and resistance are observed. Previous investigations have suggested copper complexes as a novel class of tumor-cell apoptosis inducers. The present study aimed to evaluate the anti-breast cancer activities of two polypyridyl-based copper(II) complexes, [Cu(tpy)(dppz)](NO3)2 (1) and [Cu(tptz)2](NO3)2 (2) (tpy = 2,2':6',2″-terpyridine, dppz = dipyrido[3,2-a:2',3'-c]phenazine, tptz = 2,4,6-tris(2-pyridyl)-1,3,5-triazine), using human breast adenocarcinoma cell line (MCF-7). The ability of the complexes to cleave supercoiled DNA in the presence and absence of external agents was also examined. The apoptotic activities of the complexes were assessed using flow cytometry, fluorescence microscope and western blotting analysis. Our results indicated the high DNA affinity and nuclease activity of complexes 1 and 2. The cleavage mechanisms between the complexes and plasmid DNA are likely to involve a singlet oxygen or singlet oxygen-like entity as the reactive oxygen species. Complexes 1 and 2 also significantly inhibited the proliferation of MCF-7 cells in a dose-dependent manner (IC50 values = 4.57 and 1.98 µM at 24 h, respectively). Complex 2 remarkably induced MCF-7 cells to undergo apoptosis, which was demonstrated by cell morphology, annexin-V and propidium iodide staining. The caspase cascade was activated as shown by the proteolytic cleavage of caspase-3 after treatment of MCF-7 cells with complex 2. Additionally, complex 2 significantly increased the expression of the Bax-to-Bcl-2 ratio to induce apoptosis. In conclusion, these results revealed that complex 2 may be a potential and promising chemotherapeutic agent to treat breast cancer.

Spectroscopic, biological, and molecular modeling studies on the interactions of [Fe(III)-meloxicam] with G-quadruplex DNA and investigation of its release from bovine serum albumin (BSA) nanoparticles.

The guanine-rich sequence, specifically in DNA, telomeric DNA, is a potential target of anticancer drugs. In this work, a mononuclear Fe(III) complex containing two meloxicam ligands was synthesized as a G-quadruplex stabilizer. The interaction between the Fe(III) complex and G-quadruplex with sequence of 5'-G3(T2AG3)3-3' (HTG21) was investigated using spectroscopic methods, molecular modeling, and polymerase chain reaction (PCR) assays. The spectroscopic methods of UV-vis, fluorescence, and circular dichroism showed that the metal complex can effectively induce and stabilize G-quadruplex structure in the G-rich 21-mer sequence. Also, the binding constant between the Fe(III) complex and G-quadruplex was measured by these methods and it was found to be 4.53(±0.30) × 10(5) M(-1)). The PCR stop assay indicated that the Fe(III) complex inhibits DNA amplification. The cell viability assay showed that the complex has significant antitumor activities against Hela cells. According to the UV-vis results, the interaction of the Fe(III) complex with duplex DNA is an order of magnitude lower than G-quadruplex. Furthermore, the release of the complex incorporated in bovine serum albumin nanoparticles was also investigated in physiological conditions. The release of the complex followed a bi-phasic release pattern with high and low releasing rates at the first and second phases, respectively. Also, in order to obtain the binding mode of the Fe(III) complex with G-quadruplex, molecular modeling was performed. The molecular docking results showed that the Fe(III) complex was docked to the end-stacked of the G-quadruplex with a π-π interaction, created between the meloxicam ligand and the guanine bases of the G-quadruplex.

Experimental and molecular modeling studies of the interaction of the polypyridyl Fe(II) and Fe(III) complexes with DNA and BSA.

Two mononuclear iron complexes, [Fe(tppz)2](PF6)2·H2O (1) and Fe(tppz)Cl3·2CHCl3 (2) where tppz is (2,3,5,6-tetra(2-pyridyl)pyrazine), have been synthesized and characterized by elemental analysis, spectroscopic methods (UV-Vis and IR) and single crystal X-ray structure analysis. The interaction of (1) as the nitrate salt ([Fe(tppz)2](NO3)2) with calf-thymus DNA (CT-DNA) has been monitored by UV-Vis spectroscopy, competitive fluorescence titration, circular dichroism (CD), voltammetric techniques, viscosity measurement, and gel electrophoresis. Gel electrophoresis of DNA with [Fe(tppz)2](NO3)2 demonstrated that the complex also has the ability to cleave supercoiled plasmid DNA. The results have indicated that the complex binds to CT-DNA by three binding modes, viz., electrostatic, groove and partial insertion of the pyridyl rings between the base stacks of double-stranded DNA. Molecular docking of [Fe(tppz)2](NO3)2 with the DNA sequence d(ACCGACGTCGGT)2 suggests the complex fits into the major groove. The water-insoluble complex (2) can catalyze the cleavage of BSA at 40 °C. There are no reports of the catalytic effect of polypyridyl metal complexes on the BSA cleavage. Molecular docking of (2) with BSA suggests that, when the chloro ligands in the axial positions are replaced by water molecules, the BSA can interact with the Fe(III) complex more easily.

A mononuclear zinc(II) complex with piroxicam: crystal structure, DNA- and BSA-binding studies; in vitro cell cytotoxicity and molecular modeling of oxicam complexes.

A new mononuclear Zn(II) complex, trans-[Zn(Pir)2(DMSO)2], where Pir(-) is 4-hydroxy-2-methyl-N-2-pyridyl-2H-1,2-benzothiazine-3-carboxamide-1,1-dioxide (piroxicam), has been synthesized and characterized. The crystal structure of the complex was obtained by the single crystal X-ray diffraction technique. The interaction of the complex with DNA and BSA was investigated. The complex interacts with FS-DNA by two binding modes, viz., electrostatic and groove binding (major and minor). The microenvironment and the secondary structure of BSA are changed in the presence of the complex. The anticancer effects of the seven complexes of oxicam family were also determined on the human K562 cell lines and the results showed reasonable cytotoxicities. The interactions of the oxicam complexes with BSA and DNA were modeled by molecular docking and molecular dynamic simulation methods.

A mononuclear Ni(II) complex with 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine: DNA- and BSA-binding and anticancer activity against human breast carcinoma cells.

DNA- and BSA-binding properties of a mononuclear Ni(II) complex, [Ni(dppt)2Cl2] (dppt = 5,6-diphenyl-3-(2-pyridyl)-1,2,4-triazine), have been investigated under physiological conditions. The interaction of the complex with the fish sperm DNA (FS-DNA) has been studied by UV-Vis absorption, thermal denaturation, viscosity measurement, competitive DNA-binding studies with ethidium bromide (EB) by fluorescence, and gel electrophoresis technique. The experimental results indicate that the complex interacts with DNA by intercalative binding mode. The competitive study with ethidium bromide (EB) shows that the complex competes for the DNA-binding sites with EB and displaces the DNA-bound EB molecule. The interactions of the dppt ligand and the complex with BSA have been studied by UV-Vis absorption and fluorescence spectroscopic techniques. The values of Kb for the BSA-dppt and the BSA-complex systems at room temperature were calculated to be 0.14×10(4) M(-1) and 0.32×10(5) M(-1), respectively, indicating that the complex has stronger tendency to bind with BSA than the dppt ligand. The quenching constants (Ksv), binding constants (Kbin), and number of binding sites (n) at different temperatures, as well as the binding distance (r) and thermodynamic parameters (ΔH°, ΔS° and ΔG°) have been calculated for the BSA-dppt and the BSA-complex systems. The cytotoxicities of the dppt ligand and the complex have been also tested against the human breast adenocarcinoma (MCF-7) cell line using the MTT assay. The results indicate that the dppt ligand and the complex display cytotoxicity against human breast cancer cell lines (MCF-7) with the IC50 values of 17.35 µM and 13.00 µM, respectively. It is remarkable that the complex can introduce as a potential anticancer drug.

Preparation of new fluorophore lanthanide complexes-Cloisite nanohybrids using the tricationic Pr(III), Gd(III) and Dy(III) complexes with 9,10-phenanthrenequinone.

New fluorophore lanthanide complexes-Cloisite (LCs-C) nanohybrids have been prepared by the intercalation reaction of Cloisite Na(+) with the tricationic lanthanide complexes (1-3), [M(PQ)3(DMF)2(H2O)2](3+) (M=Pr(III) (1), Gd(III) (2), and Dy(III) (3); PQ=9,10-phenanthrenequinone), in aqueous solutions. The X-ray diffraction analysis of the modified clays (LCs-C) showed an increase in the interlayer distance (d) as compared to the pure Cloisite Na(+). Field-emission scanning electron microscopy (FE-SEM) was used to study the morphology of the modified clays and the results were demonstrated a homogeneous morphology for the nanohybrids. The thermal behavior of the LCs-C nanohybrids was investigated using thermogravimetric analysis. Solid-state fluorescence properties of the LCs-C nanohybrids were also investigated. The results show that all tricationic complexes have a significant fluorescence at room temperature when the complexes are adsorbed onto Cloisite.

Preparation, characterization and solid-state emission of metal complex-cloisite nanohybrids (MC-C, M = Ru (II) and Cu (II)).

The presence of Na(+) in the Cloisite Na(+) mineral allows modification of its interlayer space to achieve a better compatibility with the host matrix and ion-exchange with a cationic metal complex. The aim of this research is to prepare two new metal complex-Cloisite (MC-C) nanohybrids using reaction of Cloisite Na(+) with the cationic Ru (II) and Cu (II) complexes, [Ru (tpy) 2] (2+) and [Cu (Pir) (phen) (H2O) 2](+), in an aqueous solution for the first time. The X-ray diffraction (XRD) analysis of the modified clays has shown an increase in its interlayer distance as compared to the unmodified Cloisite Na(+). The positions of the basal reflections in the XRD patterns of the modified clays were shifted to a higher d value indicating the expansion in their interlayer distances. The field-emission scanning electron microscopy has shown a homogeneous morphology for the modified clays. The thermal behavior of these novel hybrid materials was also investigated by thermogravimetric analysis. The solid state fluorescence spectra of the modified clays have shown that both cationic complexes exhibit a significant fluorescence emission at room temperature when intercalated into Cloisite.