Hypochromic Effect Research Articles

Ti-co-Ce oxide decorated chitosan fiber oxidase mimic identified for portable monitoring of S2-, CrO42- and Fe2+ assisted with a smartphone.

Environmental safety and protection is one of the most concerned topics nowadays. To conveniently monitor toxic S2-/CrO42- and to regulate bioactive Fe2+, Ti-co-Ce oxide decorated chitosan fiber (Ti-co-Ce ox@CC) was developed using microwave-assisted hydrothermal method. The integration of chitosan fiber and nano Ti-co-Ce oxide endowed Ti-co-Ce ox@CC with superior oxidase-like activity and improved water-dispersibility. It could quickly accelerate the oxidization of 3,3',5,5'-tetramethyl benzidine (TMB) with Vmax/Km of 6.67×10-8M·s-1/0.0178mM, much better than these (4.31×10-8M·s-1/0.0471mM) for Ti-co-Ce oxide only. Trace S2-, CrO42- or Fe2+ could selectively alter the oxidase-like activity with clear hyperchromic or hypochromic effect. Under the optimized conditions, there expressed excellent linear relationships between A652 and cS2-, cCrO42- or cFe2+ with ideal limits of detection (LOD) of 7.8×10-9M, 5.0×10-8M and 6.5×10-8M respectively. What's more, the red-green-blue (RGB) values analyzed by a smartphone also expressed nice linear relationships with satisfactory LODs of 3.8×10-8M, 7.7×10-8M and 9.2×10-8M for S2-, CrO42- and Fe2+. The proposed Ti-co-Ce ox@CC sensing platform will provide a promising potential for on-site intelligent identification of S2-, CrO42- and Fe2+ in practice.

Structural investigation of erdafitinib, an anticancer drug, with ctDNA: A spectroscopic and computational study.

The interaction of drugs with DNA is crucial for understanding their mechanism of action, particularly in the context of gene expression regulation. Erdafitinib (EDB), a pan-FGFR (fibroblast growth factor receptor) inhibitor approved by the FDA, is a potent anticancer agent used primarily in the treatment of urothelial carcinoma. In this study, the binding interaction between EDB and calf thymus DNA (ctDNA) was assessed using molecular docking, UV-absorption spectroscopy, fluorescence spectroscopy, and circular dichroism (CD) spectroscopy. The absorption spectra indicated a hypochromic effect when EDB was combined with ctDNA. The binding constant (Ka) of EDB-ctDNA complex was calculated as 7.84×103M-1, corresponds to a free energy change (ΔG) value of approximately -5.06kcal/mol, indicating a moderate binding affinity. Fluorometric analysis revealed a static binding mechanism in the ground state, with a bimolecular enhancement constant (KB) of 7.56×1011M-1. Displacement experiments demonstrated that EDB preferentially binds to the minor groove of ctDNA, with a Ksv value of 5.14×104M-1. Further, KI quenching and CD spectroscopy confirmed the minor groove binding mode, which was associated with a decrease in the Tm from 68.28°C to 65.84°C, reflecting a destabilizing effect on DNA helix. Molecular docking supported these findings, showing that EDB exhibits a strong affinity for the minor groove of ctDNA and hydrogen bonding and Vander Waal interactions are the major forces involved in the binding. These results suggest that EDB primarily binds to the minor groove of ctDNA, which may play a role in its anticancer activity.

Synergistic Regulation of DNA Morphology by Metal Cations and Low pH.

As a flexible biomolecule, the spatial structure of DNA is variable. The effects of concentration, metal cations, and low pH on DNA morphology were studied. For the high concentration of DNA, the cross-linked branch-like or network structures were formed. For the low concentration of DNA, isolated, random and freely loose linear DNA chains were presented. These phenomena were related to the intermolecular interactions. Branch-like DNA structures were reformed with the addition of metal cations to the low concentration of DNA at pH 7-4, suggesting the negative charges of DNA were neutralized, thus transforming the spatial structure of DNA into a low charge density morphology and presenting the hypochromic effect. Compared to the monovalent alkaline metal cations, more negative charges of DNA were screened by the alkaline-earth metal cations. Distinct DNA morphologies were observed for pH 3. The linear and condensed DNA structures were simultaneously observed, which was met regardless of the solution with or without the addition of metal cations. This was further confirmed by the absorbance of DNA. Compared to the pure DNA, bulky and aggregated DNA collapsed structures were formed when the sodium and magnesium cations were added to the reaction solution. In addition, it was verified that the condensed DNA structures failed to revert back to the chain structure by neutralizing acidic solutions with alkali, but the compacted DNA spheres became loose. The conductivities of various DNA morphologies were measured. They were morphology-dependent. This study provides guidance forthe behavior of DNA in the acidic solutions and further promotes the application of DNA in DNA-based nano-optoelectronic devices.

Photoisomerization of two 2-hydroxy-5-arylazobenzaldehydes in solvents of different polarities.

Two azo dyes 2-hydroxy-5-(4-nitrophenylazo)benzaldehyde and 2-hydroxy-5-(4-chlorophenylazo)benzaldehyde dissolved in carbon tetrachloride, hexane, acetone and acetonitrile were irradiated with 365nm UV light, and processes, occurring in them, were studied by NMR and UV-vis spectroscopy. It was established that reversible trans/cis photoisomerization of the molecules occurs in the non-polar solvents and is not observed in the polar solvents. 2D NOESY NMR spectroscopy was used to identify isomers of the azo compounds. Based on the chemical shifts of the signals, it was established that these compounds are in the trans-form before UV irradiation. Spectra of the azo dyes before and after UV irradiation allowed assignment of the chemical shifts of the cis-isomers. In polar solvents these compounds undergo a hypochromic effect under heating or irradiation with UV light. Both compounds exhibit solvatochromism. The shifts in NMR signals caused by photoisomerization of the molecules were compared with the shifts in the NMR signals of other azo compounds such as Disperse Orange 3, Disperse Red 1 and azobenzene.

Evaluation of the interaction between new holmium(III) complex and DNA: A comprehensive study

Evaluation of the interaction between new holmium(III) complex and DNA: A comprehensive study

HSA, free Radicals, and antibacterial interaction with ferrous oxide nanoparticles synthesized from Amorphophallus paeoniifolius

HSA, free Radicals, and antibacterial interaction with ferrous oxide nanoparticles synthesized from Amorphophallus paeoniifolius

Conformational analysis and spectroscopic properties of antichagasic nifurtimox

Considering the health relevance of Chagas' disease, recent research efforts have focused on developing more efficient drug delivery systems containing nifurtimox (NFX). This paper comprehensively investigates NFX through conformational analysis and spectroscopic characterization. Using a conformer-rotamer ensemble sampling tool (CREST-xtb), five distinct conformers of NFX were sampled within a 3.0kcalmol-1 relative energy window. Subsequently, such structures were used as inputs for geometry optimization by density functional theory (DFT) at B3LYP-def2-TZVP level of theory. Notably, harmonic vibrational frequencies were calculated to establish an in-depth comparison with experimental results and existing literature for the NFX or similar molecules and functional groups, thereby achieving a widely reasoned assignment of the mid-infrared band absorptions for the first time. Moreover, UV-VIS spectra of NFX were obtained in several solvents, enabling the determination of the molar absorptivity coefficient for the two electronic transitions observed for NFX. Among the aprotic solvents, a bathochromic effect was observed in the function of the dielectric constants. Furthermore, a hypochromic effect was observed when the drug was dissolved in protic solvents. These findings offer crucial support for new drug delivery systems containing NFX while demonstrating the potential of spectrophotometric studies in establishing quality control assays for NFX drug products.

Flavones in pomelo peel resist fibril formation of human islet amyloid polypeptide

Flavones in pomelo peel resist fibril formation of human islet amyloid polypeptide

Biocompatible Folic-Acid-Strengthened Ag-Ir Quantum Dot Nanozyme for Cell and Plant Root Imaging of Cysteine/Stress and Multichannel Monitoring of Hg2+ and Dopamine.

To boost the enzyme-like activity, biological compatibility, and antiaggregation effect of noble-metal-based nanozymes, folic-acid-strengthened Ag-Ir quantum dots (FA@Ag-Ir QDs) were developed. Not only did FA@Ag-Ir QDs exhibit excellent synergistic-enhancement peroxidase-like activity, high stability, and low toxicity, but they could also promote the lateral root propagation of Arabidopsis thaliana. Especially, ultratrace cysteine or Hg2+ could exclusively strengthen or deteriorate the inherent fluorescence property with an obvious "turn-on" or "turn-off" effect, and dopamine could alter the peroxidase-like activity with a clear hypochromic effect from blue to colorless. Under optimized conditions, FA@Ag-Ir QDs were successfully applied for the turn-on fluorescence imaging of cysteine or the stress response in cells and plant roots, the turn-off fluorescence monitoring of toxic Hg2+, or the visual detection of dopamine in aqueous, beverage, serum, or medical samples with low detection limits and satisfactory recoveries. The selective recognition mechanisms for FA@Ag-Ir QDs toward cysteine, Hg2+, and dopamine were illustrated. This work will offer insights into constructing some efficient nanozyme sensors for multichannel environmental analyses, especially for the prediagnosis of cysteine-related diseases or stress responses in organisms.

Exploring the interaction of tepotinib with calf thymus DNA using molecular dynamics simulation and multispectroscopic techniques

In recent times, there has been a surge in the discovery of drugs that directly interact with DNA, influencing gene expression. As a result, understanding how biomolecules interact with DNA has become a major area of research. One such drug is Tepotinib (TPT), an FDA-approved anti-cancer medication known as a MET tyrosine kinase inhibitor, used in chemotherapy for metastatic non-small cell lung cancer (NSCLC) with MET exon 14 skipping alterations. In our study, we adopted both biophysical and in-silico methods to investigate the binding relationship of TPT and ctDNA. The absorption spectra of ctDNA exhibited a hypochromic effect when titrated with TPT and the binding constant of TPT-ctDNA complex was calculated, Ka=9.91×104 M-1. By computing bimolecular enhancement constant (KB) and thermodynamic enhancement constant (KD) in fluorometric investigations, it was found that the fluorescence enhancement is a result of a static process involving the ctDNA-TPT complex formation in the ground state, as opposed to a dynamic process. The displacement assay results further supported this finding, showing that TPT exhibits a binding preference for minor groove of ct-DNA and was also demonstrated by KI quenching and CD spectroscopy. The molecular docking and molecular dynamic simulations validated TPT's groove binding nature and binding pattern with ctDNA, respectively. Thus, the results of our present investigation offer valuable insights into the interaction between TPT and ctDNA. It is evident that TPT, as an anti-cancer medication, binds to the minor groove of ctDNA.

Synthesis, spectroscopic characterization studies of chelating complexes and their applications as antimicrobial agents, DNA binding, molecular docking, and electrochemical studies

N,N′‐bis(2,4‐dihydroxy benzaldehyde‐1,2‐diaminobenzene) (H4L) formed from the reaction of 2,4‐dihydroxybenzaldehyde and 1,2‐diaminobenzene was complexed with Cu (II), Co (II), Ni (II), Mn (II), and UO2(II) ions. The formed complexes have been characterized by their physical data, spectral studies such as FT‐IR, Uv–Vis., 1H & 13C NMR, Mass, elemental microanalysis (C.H.N.), thermal analysis, X‐ray diffraction, and magnetic susceptibility measurements. The molecular docking between the protein receptors of the H4L ligand and its complexes was studied as theoretical method. The ligand and its metal complexes (1–5) were tested for their ability to inhibit the growth of various pathogenic microbial strains. The biological significance of the Schiff base compound and complexes as antifungal, antibacterial, and anticandidal agents as well as cytotoxicity was studied. The tested microorganisms respond better to the metal complexes than the Schiff base ligand. In comparison to the ligand, complexes, and penicillin, the UO2(II) complex (5) demonstrated the strongest antibacterial activity. In comparison to ligand, complexes, and miconazole, the UO2(II) complex (5) has antifungal activity against Aspergillus niger and Candida albicans. Complexes (1) and (5) have higher activity of antibacterial than other complexes against Pseudomonas sp. and the highest antifungal and anticandidal activity in comparison with miconazole. The ligand and its complexes showed a dose‐dependent antibacterial action according to the minimum inhibition concentration test. Using Tafel polarization and electrochemical impedance spectroscopy experiments, the protective impact of the bis‐Schiff base ligand (H4L) ligand versus Q235 Steel and its adsorption performance were investigated. The interaction between H4L Schiff base and complexes (1)–(5) and calf thymus DNA shows hypochromism effect coupled with obvious bathochromic shift.

Synthesis of carbohydrate based polythiophene graft poly(N,N-dimethylaminoethyl methacrylate)-co-poly(GLU-HEM) copolymer for lectin sensing

Sensing of lectins are utmost necessary for its inflammatory, digestive disorder, gut pains and toxicity to human beings and for this purpose we have chosen polythiophene (PT) for its exciting optoelectronic properties. Because of precise carbohydrate specificities of lectin and to make PT water soluble for sensing of lectin, we have synthesized polythiophene-g-poly(N,N-dimethylaminoethyl methacrylate) -co-poly(glucose-hydroxyethyl methacrylate) (PT-g-pDMAEMA-co-pGLU-HEM), [PTDG]) from polythiophene macroinitiator (PTI) by copolymerizing DMAEMA and GLU-HEM monomers mixture with CuCl/HMTETA catalyst/ligand followed by hydrolysis using alcoholic NaOMe solution. The Mn of PTI was 38000, polydispersity 2.5, head-tail (H-T) regioregularity 70 mol % and Mn of unhydrolyzed PTDG is 98,900. The UV-Vis spectra of PTDG solution shows two absorption peaks at 430 and 462 nm but it shows a sharp emission peak at 544 nm which quenches with increasing pH. Concanavalin A (ConA) shows an absorbance peak at 278 nm and with addition of PTDG solution absorbance intensity increases showing hypochromic effect. Benesi–Hildebrand plot of reciprocal molar extinction coefficients with concentration suggests 1:1 complex formation between PTDG and ConA. With addition of ConA fluorescence quenching of PTDG solution occurred and using the fluorescence intensity ratio vs concentration plot the limit of detection (LOD) of Con A lectin is found to be 57 µg/L and storing the polymer solution for two months exhibits good durability. The morphology of PTDG changes from vesicle to compound micellar aggregate on addition of Con A lectin.

Comparative investigation on interaction mechanism and native conformation of human serum albumin with organometallic iridium(III) complexes via spectroscopic and electrochemical approaches

Organometallic iridium(III) complexes, as high-efficient phototherapic drugs for cancer therapy and tumor treatment, have attracted widespread interest in diverse areas. To further clarify the biological functions of iridium(III) complexes, the interaction mechanism and native conformation of human serum albumin (HSA) affected by three organometallic iridium(III) complexes containing curcuminoid ligands were systematically and comparably investigated via various spectroscopic and electrochemical approaches. The results revealed that three iridium(III) complexes reacted with HSA tightly at its Sudlow's site I under the binding forces of van der Waals interaction, protonation, and hydrogen bond, leading to the hypochromic effect in the absorption spectrum of HSA and the static quenching in the intrinsic fluorescence of HSA. Three iridium(III) complexes disturbed the native conformation of HSA by reducing its α-helical content, finally reducing the melting temperature and the thermal stability of HSA. In comparison, the iridium(III) complex containing curcuminoid ligand with bigger spatial steric-hindrance effect and stronger chemical polarity was prone to binding with HSA more tightly and subsequently affecting its native conformation and biological function more prominently. This research finding reveals the interaction mechanisms of organometallic iridium(III) complexes with HSA and evaluates the function of curcuminoid ligands during their binding interactions, which pays the way for the targeted design and the potential application of novel iridium(III) complexes in biological fields.

Exploring the Effects of Cramped-Impact-Type Mechanical Action on Active Pharmaceutical Ingredient (Levofloxacin)—Prospects for Pharmaceutical Applications

Mechanochemistry is one of the ten great discoveries of green chemistry methods for synthesizing new substances. A drug substance from the fluoroquinolone group was exposed to high-intensity mechanical impacts using a laboratory knife mill for 21 min and constantly monitored by analyzing samples extracted every 3 min with DLS, SLS, LALLS, 2D-LS, optical and digital microscopy, FTIR, and Spirotox methods. A dispersity phenomenon was detected in an area where catastrophic dislocations formed and multiplied via laser methods. The positive correlation between the temperature of deformation and stress was demonstrated, similar to a typical stress–strain curve of a Bochvar–Oding curve and Young’s modulus: the angular coefficient of the straight section to OX was tgα = 10 min−1. Z-Average, ζ-potential, and polydispersity index dependences were represented as discontinuous periodic oscillations analogous to the defect and impurity transitions near the dislocation core. Deformation r from the high-intensity mechanical impact resulted in covalent bonds showing hyper- and hypochromic effects under FTIR spectra, a bathochromic shift of the maximum, and an oscillation emission at 3240 cm−1. A 2D-LS fingerprint diagram obtained via the topological convolution of the light scattering matrix made it possible to distinguish the off-loading samples from the native substance. The investigation of the dissolution kinetics in water via laser diffraction led to conclusions about the limiting diffusion stage and the acceleration of the mechanoactivation of the solid body’s dissolution under both linear and plastic deformation. The acceleration of obsEa of the cell death process in the temperature range from 296 to 302 K indicated a significant (2.5-fold) decrease in the toxicity of the aqueous 9 mM (1:3) sample solution at 21 min compared to that of the native levofloxacin. Adherence to the mechanochemistry laws provides an opportunity for drug repositioning to change their brand status by identifying new physicochemical and biological properties.

Transition metal salphen DNA complexes as biosensor application for detecting various mosquito viruses

PurposePiperidine side chain-functionalized N, N′-bissalicylidene phenylene di amine di-anion (salphen) consisting of salphen-Zn and salphen-Cu are able to intercalate with nucleic base stacking of DNA and can be applied as an optical DNA hybridization detector. Attaching DNA and salphen to glass surfaces has been done via coating the surface with the silane coupling agents containing 3-aminopropyltriethoxysilane that was synthesized for acting as a high-affinity RNA carrier matrix. The Schiff base salphen-zinc (II) and salphen-Cu (II) complexes-labelled probe to target nucleic acid renders a colour change of the DNA biosensor to a green and red background colour for zinc and copper, respectively. This study aims to indicate that the DNA biosensor data with high efficiency is used for detection of dengue virus serotypes 2 (DENV-2) and Chikungunya virus (CHIKV) concentration via salphen-Zn (II) and salphen-Cu (II), respectively, in human samples.Design/methodology/approach1H-NMR and 13C-NMR have been used via PerkinElmer LAMBDA 35 instrument. The authors also used a double beam spectrophotometer with (CH3)4Si (TMS) as reference and dimethyl sulfoxide as solvent reference in pH = 7.0. Various DNA concentrations have been used for UV spectrophotometry at 300 nm and 400 nm for zinc and copper complexes, respectively. BRUKER mass spectra with DIONEX Ultimate 3000 LC model were used for all measurements. Mettler Teledo model (DSC882e) of differential scanning calorimeter (DSC) was used for measure the melting temperature of metal zinc and copper complexes. The morphology of the silica Nano spheres (SiNs) were scanned by FESEM with Model JSM-6700F from Japan.FindingsThe Cu (II) and Zn (II)-salphen-viruses DNA system for CHIKV and DENV-2, respectively, in different concentration have been investigated via various spectroscopies (Figure 3). CHIKV and DENV-2 DNA were selected from human saliva and urine samples as models for conformations of human G4-DNA. By increasing the amounts of DNAs, and G4, the UV–Vis bands of located above 300 nm, experienced a hypochromic effect. The Cu2+ complex exhibits selectivity towards the G4, and there is a similar affinity for Zn2+ complex binds to the G4. These results collectively suggest that the Cu2+ complex is stronger than the Zn2+ complex. The authors have found copper (II) and zinc (II) compounds and nucleic acid-complexes are strongly fluorescent molecules in the low energy range, from the visible to the near-infrared. Since the fluorescent emission of Zn (II) and Cu (II) complexes are enhanced by the binding to nucleic acids upon visible light exposure when bound to DNA. These complexes are important as selective fluorescent probes for nucleic acids and to highlight their potential application. UV–vis spectroscopy is an accurate for finding the extent of ligand interaction with DNA and metallic complexes–DNA binding. Generally, the binding of intercalative compounds to DNA can be characterized through absorption spectral titrations, where lowering in absorbance (hypochromism) and shift to longer wavelengths (red shift) were observed in this work.Originality/valueThe serum samples have been provided as citrate and collected in tubes after blood is allowed to clot. Then, it has been separated by centrifugation, and the authors have kept serum refrigerated at 4°C or frozen at –20°C. It is notable; specimens have been confirmed by Centres for Disease Control (CDC)-Dengue Branch previously. For the work, these samples have been frozen previously, and the diagnostic practiced tests at the CDC-Dengue Branch have been validated in serum and plasma. Therefore, plasma separated in lavender or heparins are suitable and acceptable for serology testing.

A comprehensive biophysical and theoretical study on the binding of dexlansoprazole with human serum albumin

A comprehensive biophysical and theoretical study on the binding of dexlansoprazole with human serum albumin

Tunable Photochromism of Spirooxazine in the Solid State: A New Design Strategy Based on the Hypochromic Effect.

As an important organic photofunctional material, spirooxazine (SO) usually does not exhibit photochromism in the solid state since the intermolecular π-π stacking impedes photoisomerization. Developing photochromic SO in the solid state is crucial for practical applications but is still full of challenges. Here, a series of spirooxazine derivatives (SO1-SO4) with bulky aromatic substituents at the 4- and 7-positions of the skeleton, which provide them with a large volume with which to undergo solid-state photochromism under mild conditions, is designed and synthesized. All the compounds SO1-SO4 exhibit tunable solid photochromism without ground colors, excellent fatigue resistance, and high thermal stability. Notably, it takes only 15s for SO4 to reach the saturation of absorption intensity, thought to represent the fastest solid-state photoresponse of spirooxazines. X-ray crystal structures of the intermediate compound SO0 and the products SO1-SO2 as well as computational studies suggest that the bulky aromatic groups can lead to a hypochromic effect, allowing for the photochromism of SO in the solid state. The ideal photochromic properties of these spirooxazines open a new avenue for their applications in UV printing, quick response code, and related fields.

New Heterocyclic Organo-Chalcogenide Compounds: Synthesis, Physicochemical Characterization, and Evaluation of Anticancer Activity against Breast Cancer Cells

This work aimed to synthesize, characterize and evaluate the thermal stability of new sulfur and selenium organochalcogenide derivatives and to test the cytotoxic activity against breast adenocarcinoma cell line (MCF-7) through conducting MTT assay and AO/EB dual staining-technique. Two series of ten organo-chalcogen compounds: 4-(substituted)phenylthiomorpholine-3,5-dione and 4-(substituted)phenylselenomorpholine-3,5-dione were prepared by the reaction of Na2S·3H2O and NaHSe with N-(substituted)phenyl-2-chloro-N-(2-chloroacetyl)acetamide, respectively, under nitrogen atmosphere to give the corresponding cyclic chalcogenide ligands. All new compounds were characterized by melting point, FTIR, elemental analysis, UV-Visible, 1H-NMR and 13C-NMR. Meanwhile, TG/DTA analysis of some of these ligands was conducted to evaluate the thermal stability, kinetic, and characteristic thermodynamic parameters. Absorption spectroscopy was used to investigate these compounds with human DNA. The experimental results investigated a hypochromic effect via intercalation binding mode. The role of the prepared ligands in breast cell lines has been investigated by conducting MTT assay via spectroscopic techniques on HBL100 and MCF-7, normal and cancer breast cell lines, respectively. Cell death was seen after AO/EB dye staining method employing the fluorescence microscopy technique. The results revealed that these compounds possess cytotoxic activity on the MCF-7 and HBL-100 cell lines at a fixed concentration.

Unveiling the tartrazine binding mode with ds–DNA by UV–visible spectroscopy, electrochemical, and QM/MM methods

Here, we studied the interaction between the food colorant tartrazine (TZ) and double stranded DNA (dsDNA), using spectroscopic, electrochemical, and computational methods such as QM/MM combined with TD-DFT. Despite the UV-vis spectroscopy is widely used to study the interaction between molecules, for the case of TZ there are discrepancies in the analyses presented in the literature available, presenting both hyperchromic and hypochromic effects and consequently different rationalizations for their results. Herein we propose the combination of UV-vis experiments with the design of high-level computational models capable of reproducing the experimental behavior to finally define the proper binding mode at the molecular scale together with the rationalization of the experimental optical response due to the complex formation. To complement the UV-vis experiments, we propose the use of electrochemical measurements, to support the results obtained through UV-vis spectroscopy, as it has been successfully used for the determination of interaction modes between small molecules and biomolecules in any condition. Our UV-vis spectroscopy experiments showed only a hypochromic effect of the absorption spectra of TZ after interaction with DNA, indicative of TZ being deeply buried in the DNA structure. The effect of ionic strength in the experimental procedures led to the dissociation of TZ, thus indicating that the interaction mode was groove binding. On the other hand, the electrochemical studies showed an irreversible reduction peak of TZ, which after the interaction with DNA exhibited a positive shift in potential that can be attributed to groove binding. The binding constant for TZ-DNA was calculated as 4.45x104M-1 (UV-vis) and 5.75x104M-1 (electrochemistry), in line with other groove binder azo dyes. Finally, through the QM/MM calculations we found that the minor-groove binding mode interacting in zones rich in adenine and thymine was the model best suited to reproduce the experimental UV-vis response.

Structural elucidation of new ferrocene appended scaffold and their metal complexes: Comparative in vitro DNA/BSA binding and antibacterial assay

Structural elucidation of new ferrocene appended scaffold and their metal complexes: Comparative in vitro DNA/BSA binding and antibacterial assay