Fluorescence Titration Method Research Articles

A Novel Rhodamine‐Tetraphenylporphyrin Fluorescence Probe for Imaging Mercury In Vitro and In Vivo

ABSTRACTA highly selective fluorescent sensor Por‐RBO for determination of Hg2+ was designed and synthesized with Rhodamine B and Tetraphenylporphyrin. The sensor can determine the Hg2+ of a solution within the pH 5.0–8.0, free from interference of other metal ions. When detected in buffer solution, the fluorescence was the strongest when five times the concentration of Hg2+ ion was added. Calculated by fluorescence titration method, the detection limit of sensor Por‐RBO for Hg2+ ion was as low as 0.12 μmol/L. The geometries of Por‐RBO and Por‐RBO‐Hg2+ were optimized at the B3LYP/6‐31G** level by density functional theory. The charge distribution, orbital interactions, and bonding characteristics were analyzed and compared in detail to discuss the recognition mechanism and structure–fluorescence property relationships. The results of cell fluorescence imaging and CCK‐8 experiments indicate that the sensor Por‐RBO exhibits lower cytotoxicity. Por‐RBO can be used for fluorescence distribution imaging of Hg2+ in living cells.

Synthesis, crystal structure, Hirshfeld surface analysis, DFT computations and protein binding efficiency of a 1-D Ni(II) chain derived from a tridentate Schiff base ligand

A new Ni(II)-azido 1-D coordination polymer, [Ni2L2(μ1,1-N3)(μ1,3-N3)]n, was obtained through reaction of 1-[(3-dimethylamino-propylimino)-methyl]-naphthalen-2-ol (HL) and the perchlorate salt of nickel(II) in the presence of pseudohalide azide. X-ray crystallography and spectroscopic experiments (IR and UV-Vis) were used to describe this coordination polymer (CP). Single crystal X-ray studies revealed that the CP is a one-dimensional chain of Ni(II) in which the neighboring dimeric units (triply bridged by di-μ2-phenoxidoand µ1,1-N3) are further connected by μ1,3-azido bridges in a zig-zag fashion. The cooperative participation of N···H hydrogen bonding, π···π stacking and C-H···π interactions occur during crystal packing. A 2-D supramolecular architecture with star-shaped voids results from additional C–H···π stacking interactions. Hirshfeld surface analysis was used to look at the intermolecular interactions. DFT studies were carried out to calculate the HOMO-LUMO band gap of the ligand as well as the coordination polymer. Interaction of the CP with bovine serum albumin (BSA) protein was investigated spectroscopically by absorption and fluorescence titration methods. The result showed that the CP could quench the intrinsic fluorescence of BSA. Fluorescence resonance energy transfer (FRET) studies revealed that energy transfer takes place from BSA to the CP. Cyclic voltammetry of the CP indicated an irreversible cathodic redox couple assigned to Ni(II)/Ni(I).

Spatial distribution of sediment dissolved organic matter in oligotrophic lakes and its binding characteristics with Pb(II) and Cu(II).

Dissolved organic matter (DOM), the most active component in interstitial waters, determines the stability of heavy metals and secondary release in sediments. However, little is known about the composition and metal-binding patterns of DOM in interstitial water from oligotrophic lakes affected by different anthropogenic perturbations. Here, 18 interstitial water samples were prepared from sediments in agricultural, residential, tourist, and forest regions in an oligotrophic lake (Shengzhong Lake in Sichuan Province, China) watershed. Interstitial water quality and DOM composition, properties, and Cu(II)- and Pb(II)-binding characteristics were measured via physicochemical analysis, UV-vis spectroscopic, fluorescence excitation-emission matrix-parallel factor analysis (EEM-PARAFAC), and fluorescence titration methods. The DOM, which was produced mainly by microbial activities, had low molecular weights, humification degrees, and aromaticity. Based on EEM-PARAFAC results, the DOM was generally composed of tryptophan- (57.7%), terrestrial humic- (18.7%), microbial humic- (15.6%), and tyrosine-like (8.0%) substances. The DOM in the metal complexes was primarily composed of tryptophan-like substances, which accounted for ~42.6% of the DOM-Cu(II) complexes and ~72.0% of the DOM-Pb(II) complexes; however, microbial humic-like substances primarily contributed to the stability of DOM-Cu(II) (logKCu = 3.7-4.6) and DOM-Pb(II) (logKPb = 4.3-4.8). Water quality parameters did not significantly affect the stability of DOM-metal complexes. We demonstrated that the metal-binding patterns of DOM in interstitial water from oligotrophic lakes are highly dependent on microbial DOM composition and are affected by anthropogenic perturbations to a lesser extent.

Water-soluble polymeric probe with tryptophan pendants for formaldehyde sensing

Formaldehyde (FA) is a grade-I carcinogen and the most reactive aldehyde in the carbonyl family, posing substantial health hazards. Herein, a water-soluble polymeric probe with side-chain tryptophan pendants is proposed that relies on an FA-induced Pictet-Spengler reaction for FA sensing in an aqueous medium. The polymeric probe shows cyan fluorescence in an aqueous medium after the interaction with FA due to the formation of a β-carboline derivative, confirmed by high-resolution mass spectrum analysis of the product from the model reaction between tryptophan methyl ester and FA. The copolymer’s sensitivity to FA in aqueous solutions at the nanomolar level is estimated using the fluorescence titration method, where ∼20-fold enhancement in fluorescence intensity is observed within 2 min when 200 µM FA is added to the aqueous solution of the copolymer. The probe can selectively detect FA using colorimetric and fluorometric methods with a detection limit as low as 25 nM. The FA-sensing mechanism is studied from the model reaction of tryptophan methyl ester (TME) with FA, and density functional theory (DFT).

Synthesis, structural characterization, and anion binding studies of bisamide functionalized molecular clefts

The utilization of amide functional groups as anion-binding sites in the structure of synthetic anion receptors has received significant attention. In this study, three new compounds, namely, N,N′-bis(2-(pyridin-2-yl)ethyl)pyridine-2,6-dicarboxamide (L1), N,N′-bis(2-(pyridin-3-yl)ethyl)pyridine-2,6-dicarboxamide (L2), and N,N′-bis(2-(pyridin-4-yl)ethyl)pyridine-2,6-dicarboxamide (L3), have been successfully synthesized. These compounds were fully characterized using a combination of spectroscopic techniques such as Fourier transform infrared spectroscopy, gas chromatography–mass spectroscopy, 1H and 13C nuclear magnetic resonance spectroscopy, elemental analysis, and ultraviolet–visible (UV–Vis) spectroscopy. Further investigation on the potential of these compounds to bind with anions, such as chloride, nitrate, chromate, and phosphate, has been conducted using UV–Vis titration and a fluorescence titration method, and the results revealed that compound L2 has high potential to bind with chloride, chromate, and phosphate anions compared with other investigated hosts and analytes. This has opened a good opportunity for further application bisamide compound as anion sensing materials in the future.

Efficient and cost-effective determination of Cr(VI) ions using immobilized 4,5-dihydroxynaphthalene-2,7-disulfonic acid disodium salt dihydrate: a novel analytical reagent with high selectivity and sensitivity

ABSTRACT The determination of Cr(VI) ions in real-world samples is of utmost importance due to the critical role it plays in assessing and monitoring the levels of Cr(VI) contamination in water. The present study introduces a time-saving, cost-effective, selective, highly efficient and eco-friendly analytical reagent to detect Cr(VI) ions. This study presents fabrication of immobilised 4,5-dihydroxynaphthalene-2,7-disulfonic acid disodium salt dihydrate (DHNDSADNa) on a polyethylene-polyamine polyacrylonitrile (PPA) matrix for the determination of Cr(VI) ions using X-ray fluorescence, spectroscopic analysis and potentiodynamic titration methods. The findings revealed that the immobilised DHNDSADNa on the PPA matrix is a highly selective, accurate, easily regenerable, and rapid analytical reagent for the determination of Cr(VI) ions. The DHNDSADNa-anchored PPA framework demonstrated distinctive spectroscopic signals at 460 nm and 590 nm for the reagent and its complex with Cr(VI) ions, respectively. The detection limit for Cr(VI) ions was found to be 2 μg/mL, which is lower than that of DHNDSADNa in solution. Furthermore, the reagent exhibited high selectivity and efficiency for Cr(VI) ions even in the presence of other ions such as Co(II), Ni(II), Al(III), Fe(II), Ti(IV), Zr(IV), Ta(V), Mn(II), and W(VI). Last but not least, the immobilised DHNDSADNa on the PPA matrix exhibits superior analytical characteristics compared to previously utilised methods, making it a promising tool for various applications in medicine, pharmacology, biology, chemistry, and engineering.

Protein interactions and drug displacement studies of novel copper(II) and zinc(II) complexes of a dipyrazinylpyridine ligand

A one-pot method was employed for the preparation of zinc and copper complexes of 4-methoxyphenyl-2,6-di(pyrazine-2-yl)pyridine ligand (L). The complexes were designed to acknowledge their potential as selective binders with serum albumins. The reaction of the metal chlorides with an excess of ligand L yielded mononuclear [CuL2]Cl2 (1) and [ZnL2]Cl2 (2) complexes. 1H NMR, UV–Vis spectroscopy, ESR, HRMS, XRD, and elemental analysis were carried out to characterize the complexes. The interactions of the synthesized complexes with Human Serum Albumin (HSA) and their drug displacement properties using ibuprofen and warfarin were investigated with the help of spectroscopic as well as molecular modeling techniques. Complex 1 exhibited better binding capability, indicated by its binding constant value (31.2 × 104 M−1) towards HSA, than complex 2 (5.6 × 104 M−1), as depicted from UV–Visible and fluorescence spectroscopic studies. Moreover, the complexes showed better binding affinity towards HSA than the corresponding free ligand (0.2 × 104 M−1). The mechanism through which fluorescence quenching of HSA takes place (when metal complexes 1–2 were added to it) is static in nature. The Stern-Volmer (SV) equation was utilized to deduce the binding constants (Kb) through a fluorescence titration method. Moreover, structure optimization of the synthesized complexes and theoretical studies using density functional theory (DFT) has been carried out to determine the nature of the interaction of the complexes with the biomolecules.

Selective recognition of Fe2+ in aqueous solution by chalcones

Recognition of metal ions in aqueous media has direct impact for designing new supramolecular hosts for targeting biochemical pathways. In the present work we have studied the binding behavior of three simple chalcones with variation in number of phenolic OH groups. These chalcones showed very good binding capabilities towards metal ions in CH3OH-H2O (1:1, v/v) solvent system. The receptors R1 has interacted with all metal ions, which are used in the present study through 2:1 mode of complexation whereas R2 have showed equilibrium between the complexes of 2:1 and 1:1 with few exceptions. The highest association constants (K21) of R1 and R2 for Fe2+ is observed as 1.1 × 109 (4) M−1 and 2.3 × 108 (7) M−1 respectively by fluorescence titration method. But R3, which is lack of any phenolic OH group, binds all the metal ions through the formation of 1:1 mode of complex formation by exploiting the only one donor site as carbonyl ‘O’ atom resulting lower association constant for all the metal ions. So intermolecular hydrogen bonding as well as π- π stacking interaction forced the receptors R1 and R2 to arrange in a pseudo cleft orientation for the recognition of metal ions in 2:1 mode of complex formation. The binding behaviour of the receptors with few alkali metal ions (Na+, K+ and Cs+) and alkaline-earth metal ions (Mg2+, Ca2+ and Ba2+) are also studied and observed weak binding nature in compared with the transition metal ions.

Molecular docking and spectroscopic study of bovine serum albumin interaction with new anticancer Pt complex with isopentyl dithiocarbamate ligand

Although cisplatin is useful in the treatment of cancer, it has a series of side effects that limit its use. Dithiocarbamates reduce the toxicity of platinum due to their structure and the presence of S, and N donating groups. In this article, the interaction of [Pt(bpy)(isopentyl.dtc)]NO3, where bpy is bipyridine and isopentyl.dtc is isopentyl-dithiocarbamate, with BSA, bovine serum albumin has been studied. The molecular binding method, including UV-Vis and fluorescence titration, was carried out in conditions including pH = 7.4 and temperatures of 27 and 37 °C. The negative values of enthalpy (ΔH°b) and entropy (ΔS°b) show that the driving forces of this interaction are hydrogen and van der Waals, and the negative value of the Gibbs free energy, ΔG°b indicates that the interaction proceeds spontaneously. The fluorescence results showed that the quenching mechanism is the static type and the Stern Volmer constant, KSV, was also obtained. The fluorescence titration method data displayed that the quenching mechanism is static. Binding constant (Kb), binding point (n), Hill coefficients, nH, Hill constant, KH, number of binding sites, g, BSA melting temperature, Tm, were also obtained. Finally, the molecular docking method result shows the binding constant, Ki and binding free energy for the platinum complex are −6.53 and 16.39 kcal mol−1, respectively, and also the proper position of binding on BSA can be considered the site I in the subdomain IIA.

Triazole-based C3-symmetric multivalent dendritic architecture as Cu(II) ion sensor

C3-symmetric triazole-based multivalent dendritic architecture having uniform aromatic core and branches has been employed to study its metal binding ability towards Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Zn(II) ions. The dendritic architecture is found to exhibit a high affinity for Cu(II) ions and formed a solid complex with a blue shift in the dd-band of Cu(II) chloride. X-band EPR spectra at low temperature has supported a distorted tetrahedral geometry for the complex. The complex has displayed quasi-reversible redox waves in cyclic voltammetry (CV). DFT calculations have shown that Cu(II) has a high affinity for the dendritic structure, leading to high complexation energies of the order of -25 eV, showing that the complexation reactions are highly exothermic. The binding constant (K) for the Cu(II) complex has been determined using a fluorescence titration method.

Structure-activity relationship of dietary flavonoids on pancreatic lipase

Lipase is a very important digestive enzyme for triglyceride absorption in vivo. The inhibitory activities of 26 dietary flavonoids, including flavone, flavanone, isoflavone and flavanol, on lipase were determined. Flavone exhibited stronger inhibitory activity than other types of flavonoids. Among them, luteolin exhibited the strongest inhibitory activity with IC50 value of 99 ± 11 μM, followed by quercetin and baicalein. The binding affinity of these flavonoids with lipase was investigated by fluorescence titration method. The binding affinity of flavones was stronger than flavanones, and was linearly positively correlated with their inhibitory activity. The binding of flavones on lipase caused the blue-shift of fluorescence, while flavanones caused red-shift. The analysis of structure-activity relationship of flavonoids on lipase revealed that the structure of C ring is very crucial. The hydrogenation of C2=C3 bond and the absence of C=O group in C ring both caused significant decrease of inhibitory activity. Besides, the hydroxylation on ring A and B of flavones increased the activity, while glycosylation weakened the activity. Molecular docking analysis confirmed that C2=C3 bond in C ring of flavones increases the π-conjugation and contributes to maintaining the planarity of flavonoid structure, which favour its Pi-Pi interaction with lipase.

Donor-Acceptor Complexes of (5,10,15,20-Tetra(4-methylphenyl)porphyrinato)cobalt(II) with Fullerenes C60: Self-Assembly, Spectral, Electrochemical and Photophysical Properties.

The noncovalent interactions of (5,10,15,20-tetra(4-methylphenyl)porphinato)cobalt(II) (CoTTP) with C60 and 1-N-methyl-2-(pyridin-4-yl)-3,4-fullero[60]pyrrolidine (PyC60) were studied in toluene using absorption and fluorescence titration methods. The self-assembly in the 2:1 complexes (the triads) (C60)2CoTTP and (PyC60)2CoTTP was established. The bonding constants for (C60)2CoTTP and (PyC60)2CoTTP are defined to be (3.47 ± 0.69) × 109 and (1.47 ± 0.28) × 1010 M-2, respectively. 1H NMR, IR spectroscopy, thermogravimetric analysis and cyclic voltammetry data have provided very good support in favor of efficient complex formation in the ground state between fullerenes and CoTTP. PyC60/C60 fluorescence quenching in the PyC60/C60-CoTTP systems was studied and the fluorescence lifetime with various CoTTP additions was determined. The singlet oxygen quantum yield was determined for PyC60 and the intensity decrease in the 1O2 phosphorescence for C60 and PyC60 with the CoTTP addition leading to the low efficiency of intercombination conversion for the formation of the 3C60* triplet excited state was found. Using femtosecond transient absorption measurements in toluene, the photoinduced electron transfer from the CoTTP in the excited singlet state to fullerene moiety was established. Quantum chemical calculations were used for the determination of molecular structure, stability and the HOMO/LUMO energy levels of the triads as well as to predict the localization of frontier orbitals in the triads.

Cytotoxic effects of Pd(II) complexes on cancer and normal cells: Their DNA & BSA adduct formation and theoretical approaches

Herein, we report the synthesis and characterisation of a series of Pd(II) complexes: Pd(TEEDA)Cl2, C-1; [Pd(TEEDA)(OH2)2](NO3)2, C-2; [Pd(TEEDA)(l-cys)](NO3)2, C-3; [Pd(TEEDA)(NALC)], C-4; [Pd(TEEDA)(Meth)](NO3)2, C-5; and [Pd(TEEDA)(GSH)], C-6 (where TEEDA = N,N,N’-Triethylenediamine, l-cys = l-cysteine, NALC = N-acetyl-l-cysteine, Meth = dl-methionine and GSH = glutathione). UV–Vis spectroscopic characterisation was supported by TD-DFT theoretical simulation using Gaussian09 software. Different reactivity parameters were calculated from the energy difference between HOMO and LUMO of the complexes by DFT. The bonding mode of the labile ligands was confirmed by NBO analysis. Interaction of the complexes with DNA has been observed by gel electrophoresis experiment. DNA binding nature as well as binding constants of the complexes were measured with UV–Vis and fluorescence spectroscopic method. The binding nature of the complexes with DNA was confirmed by viscometric titration. Interaction of the complexes with BSA was investigated by UV–Vis and fluorescence titration method. Cytotoxic activity of the Pd(II) complexes was evaluated on A549 (lung carcinoma epithelial cells), HCT116(Colorectal Carcinoma) and HEK293 (Human embryonic kidney cells) cell lines. The ROS generation in the presence of the complexes was tested both on cancer cell lines A549 and HCT116 as well as human normal cell HEK293.

Structural Exploration and Protein Binding Efficiencies of Binuclear Dioxidomolybdenum(VI) Complexes Constructed from ONO Chelator and Linear N−N Ditopic Spacer

Binuclear dioxido Mo(VI) complexes(1 and 2) of general formula [(MoO2L1−2)2(bpe)] have been synthesized by varying a auxiliary bridging ligand on the primary ligand framework. The impact of spacer variation on metal-organic supramolecular architectures, DFT calculations and BSA binding efficiencies of the complexes has been studied. The intermolecular interactions in the crystal structures are also studied by Hirshfeld surface analysis. FRET, Time-resolved fluorescence measurement and molecular docking of the complexes were also carried out.

Alkaline N-GQDs fluorescent probe for the ultrasensitive detection of creatinine

Creatinine (Crn) is an important excretory product of the human body. Medical laboratory technology has improved over years and brought many advancements in clinical diagnostics equipment, and testing techniques and made the tests more efficient. Yet, the quantitative analysis of Crn is still carried out by the classical Jaffe’s reaction (using Picric acid (PA) with NaOH) method. Since PA is hazardous to human health, alternative solutions such as; nanoparticles and surface-modified nanoparticles can be used. Exploring the optoelectronic properties of carbon-based quantum dots for biomolecule sensing is of current interest among researchers. Nitrogen functionalized graphene quantum dots (Alk-NGQDs) measured featured Crn easier and reduced the time taken for the test carried out in laboratories. The synthesized Alk-NGQDs optical, structural, morphological properties, surface and compositions are studied through XPS, HRTEM, XRD, FTIR, and spectroscopic techniques. Alk-NGQDs at alkaline conditions (pH 9.5) form a stable complex with Crn through intermolecular charge transfer (ICT). The fluorescence titration method is used to sense Crn in commercial Crn samples and human blood serum. To understand the efficacy of sensing creatinine using Alk-NGQDs, working concentration, fluorescence quantum yield, the limit of detection, and quenching constant are calculated using the Stern-Volmer plot. The emission property of Alk-NGQDs is aimed to bring an alternative to the traditional colorimetric Jaffe’s reaction.

Design and synthesis of novel heterocyclic pivalamide ligands and their copper(II) complexes: Structure, BSA/DNA interactions and SOD synzyme activity

Four new heterocyclic pivalamide based ligands (L1-L4) and their respective mononuclear copper(II) complexes (C1 = [Cu(N-(thiazol-2-yl)pivalamide)2], C2 = [Cu(N-(5-methylthiazol-2-yl)pivalamide)2], C3 = [Cu(N-(benzothiazol-2-yl)pivalamide)2], C4 = [Cu(N-(benzoimidazol-2-yl)pivalamide)2]) were synthesized to serve as low molecular weight SOD mimics. The complexes were characterized by single crystal XRD, Hirshfeld surface analysis, FT-IR, UV–vis, EPR and ESI-MS studies. C1 crystallizes out in a triclinic system with P-1 space group, while C2 and C4 belong to P21/c and P21/n space groups respectively, from monoclinic system. The crystal structures indicate nearly square planar geometry where mononuclear copper(II) metal ions have coordinated with O and N donor atoms of the pivalamide ligands in trans fashion. All the complexes can scavenge superoxide concentration at low concentrations, in the order C2 < C3 < C1 < C4. The interaction of all the complexes with BSA (bovine serum albumin) protein investigated using fluorescence titration method indicated a static quenching mechanism (KBSA values of the order 105 M−1). The ability of the complexes to bind with calf thymus DNA were also evaluated using absorption and fluorescence titration methods and an intercalative interaction mode of the complexes with DNA was established (Kb values of the order 104 M−1). The complexes have a strong ability to cleave supercoiled plasmid DNA.

Thermodynamic and Kinetic Binding Behaviors of Human Serum Albumin to Silver Nanoparticles

A nanoparticle, under biological milieu, is inclined to be combined with various biomolecules, particularly protein, generating an interfacial corona which provides a new biological identity. Herein, the binding interaction between silver nanoparticles (AgNPs) and human serum albumin (HSA) was studied with transmission electron microscopy (TEM), circular dichroism (CD), and multiple spectroscopic techniques. Due to the ground state complex formed mainly through hydrophobic interactions, the fluorescence titration method proved that intrinsic fluorescence for HSA was probably statically quenched by AgNPs. The complete thermodynamic parameters were derived, indicating that the interaction between HSA and AgNPs is an entropy-driven process. Additionally, synchronous fluorescence and CD spectrum results suggested the conformational variation it has upon binding to AgNPs and the α-helix content has HSA visibly decreased. The kinetic experiments proved the double hysteresis effect has in HSA’s binding to the AgNPs surface. Moreover, the binding has between HSA and AgNPs follows the pseudo-second-order kinetic characteristic and fits the Freundlich model for multilayer adsorption. These results facilitate the comprehension about NPs’ underlying biological effects under a physiological environment and promote the secure applications of NPs biologically and medically.

CASTING: A Potent Supramolecular Strategy to Cytosolically Deliver STING Agonist for Cancer Immunotherapy and SARS-CoV-2 Vaccination

CASTING: A Potent Supramolecular Strategy to Cytosolically Deliver STING Agonist for Cancer Immunotherapy and SARS-CoV-2 Vaccination

DNA binding effects of 2,2′-bipyridine and 1,10-phenanthroline ligands synthesized with benzimidazole copper (II) complexes: Crystal structure, molecular docking, DNA binding and anti-cancer studies

Two new copper(II) complexes, [Cu(benzim)2(bipy)(MeOH)](ClO4)2 (Complex 1) and Cu(benzim)2(phen)(MeOH)](ClO4)2 (Complex 2)] (bipy = 2,2′-bipyridine, phen = 1,10-phenanthroline and benzim = 1-benzyl-1H-benzimidazole) have been synthesized and successfully characterized with single crystal x-ray diffraction analysis. Crystal structures of complexes revealed that both possess distorted square pyramidal geometries coordinated with a solvent molecule (CH3OH) at apical positions. The in vitro cytotoxicity of these Cu(II) complexes was carried out in HCC1428 and HUVEC cell lines. Molecular docking was also used to evaluate and understand the interaction modes of the complexes with the molecular target DNA and HSA (Human Serum Albumin). DNA binding capacities of complexes were analyzed by fluorescent titration method. Structural changes in the nucleus as a result of the effects of the complexes were discussed by viewing them with DAPI staining. Furthermore, biological activities of complexes and ligands were analyzed in silico. The cell lines IC50 results were obtained at similar rates (∼8-fold) to the constant inhibition values obtained by docking studies. In addition, the fluorescence titration and circular dichrosim studies of the compounds with dsDNA-TO complexes showed results in agreement with docking studies. In our study, it was determined that phen ligand has a much more effective biological activity than bipy ligand in copper(II) complex synthesized with benzimidazole.

An application of p-sulfonatocalix[6]arenes to attenuate cardiotoxicity of mitoxantrone in vitro: preparation, characterization and evaluation.

In this study, p-sulfonatocalix[6]arenes (SCA6) was proposed to construct a host-guest complexation to carry mitoxantrone (MIT) to maintain its anti-proliferation effect on HepG2 cells as well as to attenuate cardiotoxicity on H9C2 cells as a nano-size drug delivery system. SCA6 binding to MIT evidenced through competitive fluorescence titration method. The complex was characterized using UV-visible, Fourier transform infrared, and proton nuclear magnetic resonance (1H-NMR) spectroscopies and differential scanning calorimetry analysis. The cytotoxicity was examined by a cell counting kit-8 assay on six cells. High content analysis, cell apoptosis and cell cycle experiments were measured to investigate the mechanism of detoxification in H9C2. The host-guest complexation was formed with a stoichiometry ratio of 1:1. Cytotoxicity study demonstrated that MIT/SCA6 complex could improve the cell viability on H9C2, MCF-7, A549, Hek293 and L02 cells and remained cytotoxicity effect on HepG2 cells. High content analysis showed that MIT/SCA6 complex could enhance the cell viability, mitochondrial mass and mitochondrial membrane potential and ameliorate the nuclear swelling on H9C2 cells. Moreover, the complex were arrested in G0/G1 phase of the cell cycle and same with MIT, while the detoxication was attributed to reducing early apoptosis. The host-guest complexation between SCA6 and MIT had the ability to attenuate cardiotoxicity and provided a potential strategy for the application of soluble calixarenes in chemotherapy.