DNA as a target for lanthanide(III) complexes influence

Recovery of terbium by Lysinibacillus sp. DW018 isolated from ionic rare earth tailings based on microbial induced calcium carbonate precipitation

Microbial induced calcium carbonate precipitation (MICP) is considered as an environmentally friendly microbial-based technique to remove heavy metals. However, its application in removal and recovery of rare earth from wastewaters remains limited and the process is still less understood. In this study, a urease-producing bacterial strain DW018 was isolated from the ionic rare earth tailings and identified as Lysinibacillus based on 16S rRNA gene sequencing. Its ability and possible mechanism to recover terbium was investigated by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and fourier transform infrared spectroscopy (FTIR). The results showed that the urease activity of DW018 could meet the biomineralization requirements for the recovery of Tb3+ from wastewaters. The recovery rate was as high as 98.28% after 10 min of treatment. The optimal conditions for mineralization and recovery were determined as a bacterial concentration of OD600 = 1.0, a temperature range of 35 to 40°C, and a urea concentration of 0.5%. Notably, irrespective of CaCO3 precipitation, the strain DW018 was able to utilize MICP to promote the attachment of Tb3+ to its cell surface. Initially, Tb3+ existed in amorphous form on the bacterial surface; however, upon the addition of a calcium source, Tb3+ was encapsulated in calcite with the growth of CaCO3 at the late stage of the MICP. The recovery effect of the strain DW018 was related to the amino, hydroxyl, carboxyl, and phosphate groups on the cell surface. Overall, the MICP system is promising for the green and efficient recovery of rare earth ions from wastewaters.

One touch is all it takes: the supramolecular interaction between ubiquitin and lanthanide complexes revisited by paramagnetic NMR and molecular dynamics

The supramolecular interaction between lanthanide complexes and proteins is at the heart of numerous chemical and biological studies. Some of these complexes have demonstrated remarkable interaction properties with proteins or peptides in solution and in the crystalline state. Here we have used the paramagnetism of lanthanide ions to characterize the affinity of two lanthanide complexes for ubiquitin. As the interaction process is dynamic, the acquired NMR data only reflect the time average of the different steps. We have used molecular dynamics (MD) simulations to get a deeper insight into the detailed interaction scenario at the microsecond scale. This NMR/MD approach enabled us to establish that the tris-dipicolinate complex interacts specifically with arginines and lysines, while the crystallophore explores the protein surface through weak interactions with carboxylates. These observations shed new light on the dynamic interaction properties of these complexes, which will ultimately enable us to propose a crystallization mechanism.

A plasmid containing the human metallothionein-II gene selectively distinguishes trivalent lanthanum from several divalent heavy metal cations during monoclonal antibody-assisted agarose gel electrophoresis

Trivalent lanthanide ions are known for their ability to interact with calcium-binding sites in various proteins. There is a need to assess the bioavailability of lanthanides and other heavy metals introduced into the body as components of implants or as contrast agents. This study aimed to develop a method to address bioavailability and/or presence of trivalent lanthanide ions by examining electrophoretic mobility in an agarose gel of a plasmid harboring the human metallothionein-II gene (hMT-II). Mobility of the plasmid was specifically altered by a monoclonal antibody raised against the zinc-binding transcription factor that controls the activity of the hMT-II gene. This study showed that the plasmid acquired a lanthanide-specific mobility pattern that allowed the presence of lanthanide ions to be readily determined in a 0.8% agarose gel. These findings suggest that this plasmid/monoclonal antibody combination under selected conditions may be useful in industrial, environmental, and biomedical settings to identify, separate, or capture lanthanide ions in complex mixtures that contain an array of metal ions.

Innovative lanthanide complexes: Shaping the future of cancer/ tumor chemotherapy

Developing new therapeutic and diagnostic metals and metal complexes is a stunning example of how inorganic chemistry is rapidly becoming an essential part of modern medicine. More study of bio-coordination chemistry is needed to improve the design of compounds with fewer harmful side effects. Metal-containing drugs are widely utilized in the treatment of cancer. Platinum complexes are effective against some cancers, but new coordination compounds are being created with improved pharmacological properties and a broader spectrum of anticancer action. The coordination complexes of the 15 lanthanides or rare earth elements in the periodic table are crucial for diagnosing and treating cancer. Understanding and treating cancer requires the detection of binding lanthanide (III) ions or complexes to DNA and breaking DNA by these complexes. Current advances in lanthanide-based coordination complexes as anticancer treatments over the past five years are discussed in this study.

Synthesis, solid state characterization, theoretical and experimental spectroscopic studies of the new lanthanide complexes

Three new complexes Na[Ln(pic)₄]ּ⋅2.5H₂O (Ln = Tb, Eu or Gd; pic = picolinate) were synthesized and characterized by infrared spectroscopy, powder X-ray diffraction and thermogravimetric analyses. The molecular structures of the complexes have been determined by single-crystal X-ray diffraction. The three isostructural lanthanide complexes crystalize in the hexagonal system with space group P6₁22 to Eu complex and Gd complex and space group P6₅22 to Tb complex. In each of the complexes, the picolinate ligands are bonded to Ln³⁺ and Na⁺ ions by different coordination modes promoting polymeric structures. The photoluminescent properties of complexes were studied and combined with theoretical studies using the density functional theory (DFT: B3LYP, PBE1PBE) and the semiempirical method AM1/Sparkle from the single crystal X-ray diffraction structures to assign a suitable model for describing the system. The B3LYP DFT functional was considered the most adequate for providing structural properties of the compounds and for describing luminescence properties. The excited triplet states (T₁) and excited singlet states (S₁) of the ligand were determined theoretically using Time-dependent DFT calculations (TD-DFT: B3LYP, CAM-B3LYP and LC-wPBE) and INDO/S-CIS, with the best agreement with experimental values obtained from the LC-wPBE DFT functional. The photoluminescent spectra of the complexes and their lifetime measurements were determined indicating that the Eu complex and Tb complex display different intramolecular energy transfer mechanisms with higher efficiency to ligand-to-terbium energy transfer. In addition, the experimental and theorical Judd-Ofelt intensity parameters and quantum yields of the complexes were also determined and discussed besides to a proposed 9-state diagram to describe the luminescence properties of the Eu complex. The low value of emission quantum efficiency of ⁵D₀ emitting level of Eu(III) ion was explained by the presence of the ligand-to-metal charge transfer state (LMCT) evidenced experimentally and theoretically. A good agreement was obtained between the proposed kinetic model and experimental results showing the consistency of the set of rate equations assumed and the intramolecular pathways proposed.

Manganese(ii) complexes stimulate antitumor immunity via aggravating DNA damage and activating the cGAS-STING pathway

Activating the cyclic GMP-AMP synthase-stimulator of the interferon gene (cGAS-STING) pathway is a promising immunotherapeutic strategy for cancer treatment. Manganese(ii) complexes MnPC and MnPVA (P = 1,10-phenanthroline, C = chlorine, and VA = valproic acid) were found to activate the cGAS-STING pathway. The complexes not only damaged DNA, but also inhibited histone deacetylases (HDACs) and poly adenosine diphosphate-ribose polymerase (PARP) to impede the repair of DNA damage, thereby promoting the leakage of DNA fragments into cytoplasm. The DNA fragments activated the cGAS-STING pathway, which initiated an innate immune response and a two-way communication between tumor cells and neighboring immune cells. The activated cGAS-STING further increased the production of type I interferons and secretion of pro-inflammatory cytokines (TNF-α and IL-6), boosting the tumor infiltration of dendritic cells and macrophages, as well as stimulating cytotoxic T cells to kill cancer cells in vitro and in vivo. Owing to the enhanced DNA-damaging ability, MnPC and MnPVA showed more potent immunocompetence and antitumor activity than Mn2+ ions, thus demonstrating great potential as chemoimmunotherapeutic agents for cancer treatment.

Interaction of isoquinoline alkaloids with pyrimidine motif triplex DNA by mass spectrometry and spectroscopies reveals diverse mechanisms

Isoquinoline alkaloids represent an important class of molecules due to their broad range of pharmacology and clinical utility. Prospective development and use of these alkaloids as effective anticancer agents have elicited great interest. In this study, in order to reveal structure-activity relationship, we present the characterization of bioactive isoquinoline alkaloid-DNA triplex interactions, with particular emphasis on the sequence selectivity and preference of binding to the two types of DNA triplexes, by electrospray ionization mass spectrometry (ESI-MS) and various spectroscopic techniques. The six alkaloids, including coptisine, columbamine, epiberberine, berberrubine, jateorhizine, and fangchinoline, were selected to explore their interactions with the TC and TTT triplex DNA structures. Berberrubine, fangchinoline, coptisine, columbamine, and epiberberine have preference for TC rich DNA sequences compared to TTT rich DNA triplex based on affinity values in MS. The experimental results from different fragmentation modes in tandem MS, subtractive and hyperchromic effects in UV absorption spectra, fluorescence quenching and enhancement in fluorescence spectra, and strong conformational changes in circular dichroism (CD) hinted that the interaction between isoquinoline alkaloid-TC/TTT DNA had diverse mechanisms including at least two different binding modes: the electrostatic binding and the intercalation binding. Interestingly, columbamine, berberrubine, and fangchinoline can stabilize TTT triplex as inferred from optical thermal melting profiles, while it was not the case in TC triplex. These results provide new insights into binding of isoquinoline alkaloids to pyrimidine motif triplex DNA.

Lanthanide-based MOFs: synthesis approaches and applications in cancer diagnosis and therapy

Metal-organic frameworks (MOFs) have attracted considerable attention as emerging nanomaterials. Based on their tunable size, high porosity, and large specific surface area, MOFs have a wide range of applications in the fields of chemistry, energy, and biomedicine. However, the MOF materials obtained from lanthanides with a unique electronic configuration as inorganic building units have unique properties such as optics, magnetism, and radioactivity. In this study, various synthetic methods for preparing MOF materials using lanthanides as inorganic building units are described. Combined with the characteristics of lanthanides, their application prospects of lanthanide-based MOFs in tumor diagnosis and treatment are emphasized. The authors hope to provide methodological reference for the construction of MOF materials of rare-earth elements, and to provide ideas and inspiration for their practical applications in the field of biomedicine.

Augmentation of photophysical features and Judd-Ofelt analysis of extensively green glowing terbium (III) complexes with nitrogen donor ancillary ligands

Six green glowing terbium (III) complexes were fabricated via grinding method utilizing a prime organic ligand (L) and nitrogen donor ancillary ligands. Characterization of synthesized complexes was accomplished through various spectroscopic techniques. The significant thermal stability was determined by thermogravimetric analysis while the energy bandgap and Urbach energy were investigated through diffused reflectance spectra of these complexes. The peak observed at 548 nm in emission spectra is responsible for the virescent color of these complexes. Color purity, decay time, quantum yield, and emission intensities of ternary complexes were significantly improved as compared to binary ones due to the synergistic effect of ancillary ligands. Judd-Ofelt parameters were determined by the NIR absorption spectrum, which claims the asymmetric environment around the terbium (III) ion. CCT values advocate the applicability of these complexes in green light-emitting materials as a cool light source. The biological assignments reveal the significance of these complexes as potent antioxidants and antimicrobial agents. The energy transfer process highlights the enhancement of luminescence in these complexes via the synergic effect of ligands. Our investigation portrays that these complexes can be employed in laser technology, display devices, semiconductors, biological fields, and optoelectronic devices.

Nuclease-like metalloscissors: Biomimetic candidates for cancer and bacterial and viral infections therapy

Despite the extensive and rapid discovery of modern drugs for treatment of cancer, microbial infections, and viral illnesses; these diseases are still among major global health concerns. To take inspiration from natural nucleases and also the therapeutic potential of metallopeptide antibiotics such as the bleomycin family, artificial metallonucleases with the ability of promoting DNA/RNA cleavage and eventually affecting cellular biological processes can be introduced as a new class of therapeutic candidates. Metal complexes can be considered as one of the main categories of artificial metalloscissors, which can prompt nucleic acid strand scission. Accordingly, biologists, inorganic chemists, and medicinal inorganic chemists worldwide have been designing, synthesizing and evaluating the biological properties of metal complexes as artificial metalloscissors. In this review, we try to highlight the recent studies conducted on the nuclease-like metalloscissors and their potential therapeutic applications. Under the light of the concurrent Covid-19 pandemic, the human need for new therapeutics was highlighted much more than ever before. The nuclease-like metalloscissors with the potential of RNA cleavage of invading viral pathogens hence deserve prime attention.

Magnetic and Luminescence Properties of 8-Coordinate Holmium(III) Complexes Containing 4,4,4-Trifluoro-1-Phenyl- and 1-(Naphthalen-2-yl)-1,3-Butanedionates

A new series of mononuclear Ho³⁺ complexes derived from the β-diketonate anions: 4,4,4-trifluoro-1-phenyl-1,3-butanedioneate (btfa⁻) and 4,4,4-trifuoro-1-(naphthalen-2-yl)-1,3-butanedionate (ntfa⁻) have been synthesized, [Ho(btfa)₃(H₂O)₂] (1a), [Ho(ntfa)₃(MeOH)₂] (1b), (1), [Ho(btfa)₃(phen)] (2), [Ho(btfa)₃(bipy)] (3), [Ho(btfa)₃(di-^tbubipy)] (4), [Ho(ntfa)₃(Me₂bipy)] (5), and [Ho(ntfa)₃(bipy)] (6), where phen is 1,10-phenantroline, bipy is 2,2′-bipyridyl, di-^tbubipy is 4,4′-di-tert-butyl-2,2′-bipyridyl, and Me₂bipy is 4,4′-dimethyl-2,2′-bipyridyl. These compounds have been characterized by elemental microanalysis and infrared spectroscopy as well as single-crystal X-ray difraction for 2–6. The central Ho³⁺ ions in these compounds display coordination number 8. The luminescence-emission properties of the pyridyl adducts 2–6 display a strong characteristic band in the visible region at 661 nm and a series of bands in the NIR region (excitation wavelengths (λ_ex) of 367 nm for 2–4 and 380 nm for 5 and 6). The magnetic properties of the complexes revealed magnetically uncoupled Ho³⁺ compounds with no field-induced, single-molecule magnet (SMMs).

Lanmodulin Remains Unfold and Fails to Interact with Lanthanide Ions in Escherichia coli Cells

We report the conformation of a newly discovered specific lanthanide ions (Ln3+) binding protein, Lanmodulin (LanM), and its inteaction with Ln3+ in Escherichia coli cells using In-cell NMR. We found...

Metal Complexes as DNA Synthesis and/or Repair Inhibitors: Anticancer and Antimicrobial Agents

Medicinal inorganic chemistry involving the utilization of metal-based compounds as therapeutics has become a field showing distinct promise. DNA and RNA are ideal drug targets for therapeutic intervention in the case of various diseases, such as cancer and microbial infection. Metals play a vital role in medicine, with at least 10 metals known to be essential for human life and a further 46 nonessential metals having been involved in drug therapies and diagnosis. These metal-based complexes interact with DNA in various ways, and are often delivered as prodrugs which undergo activation in vivo. Metal complexes cause DNA crosslinking, leading to the inhibition of DNA synthesis and repair. In this review, the various interactions of metal complexes with DNA nucleic acids, as well as the underlying mechanism of action, were highlighted. Furthermore, we also discussed various tools used to investigate the interaction between metal complexes and the DNA. The tools included in vitro techniques such as spectroscopy and electrophoresis, and in silico studies such as protein docking and density-functional theory that are highlighted for preclinical development.

Diverse Coordination Numbers and Geometries in Pyridyl Adducts of Lanthanide(III) Complexes Based on β-Diketonate

Ten mononuclear rare earth complexes of formula [La(btfa)3(H2O)2] (1), [La(btfa)3(4,4′-Mt2bipy)] (2), [La(btfa)3(4,4′-Me2bipy)2] (3), [La(btfa)3(5,5′-Me2bipy)2] (4), [La(btfa)3(terpy)] (5), [La(btfa)3(phen)(EtOH)] (6), [La(btfa)3(4,4′-Me2bipy)(EtOH)] (7), [La(btfa)3(2-benzpy)(MeOH)] (8), [Tb(btfa)3(4,4′-Me2bipy)] (9) and (Hpy)[Eu(btfa)4] (10), where btfa = 4,4,4-trifuoro-1-phenylbutane-1,3-dionato anion, 4,4′-Mt2bipy = 4,4′-dimethoxy-2,2′-bipyridine, 4,4′-Me2bipy = 4,4′-dimethyl-2,2′-bipyridine, 5,5′-Me2bipy = 5,5′-dimethyl-2,2′-bipyridine, terpy = 2,2′:6′,2′-terpyridine, phen = 1,10-phenathroline, 2-benzpy = 2-(2-pyridyl)benzimidazole, Hpy = pyridiniumH+ cation) have been synthesized and structurally characterized. The complexes display coordination numbers (CN) eight for 1, 2, 9, 10, nine for 5, 6, 7, 8 and ten for 3 and 4. The solid-state luminescence spectra of Tb-9 and Eu-10 complexes showed the same characteristic bands predicted from the Tb(III) and Eu(III) ions. The Overall Quantum Yield measured (ϕTOT) at the excitation wavelength of 371 nm for both compounds yielded 1.04% for 9 and up to 34.56% for 10.

Convertible and Constrained Nucleotides: The 2'-Deoxyribose 5'-C-Functionalization Approach, a French Touch

Many strategies have been developed to modulate the biological or biotechnical properties of oligonucleotides by introducing new chemical functionalities or by enhancing their affinity and specificity while restricting their conformational space. Among them, we review our approach consisting of modifications of the 5’-C-position of the nucleoside sugar. This allows the introduction of an additional chemical handle at any position on the nucleotide chain without disturbing the Watson–Crick base-pairing. We show that 5’-C bromo or propargyl convertible nucleotides (CvN) are accessible in pure diastereoisomeric form, either for nucleophilic displacement or for CuAAC conjugation. Alternatively, the 5’-carbon can be connected in a stereo-controlled manner to the phosphate moiety of the nucleotide chain to generate conformationally constrained nucleotides (CNA). These allow the precise control of the sugar/phosphate backbone torsional angles. The consequent modulation of the nucleic acid shape induces outstanding stabilization properties of duplex or hairpin structures in accordance with the preorganization concept. Some biological applications of these distorted oligonucleotides are also described. Effectively, the convertible and the constrained approaches have been merged to create constrained and convertible nucleotides (C₂NA) providing unique tools to functionalize and stabilize nucleic acids.

Capturing the dynamic association between a tris-dipicolinate lanthanide complex and a decapeptide: a combined paramagnetic NMR and molecular dynamics exploration

In the realm of biomolecules, peptides can present a large diversity of structures. Our study sheds new light on the structural interplay between a tris-dipicolinate lanthanide probe and a decapeptide SASYKTLPRG. Although a rather trivial, electrostatically driven interaction was expected, the combination of paramagnetic NMR and molecular dynamics simulations reveals a highly dynamic association process and allows for providing extensive insights into the interaction sites and their occupancy. This study highlights the importance of a large conformational sampling to reconcile characteristic time in NMR with molecular dynamics simulations, where sampling in the microsecond range is needed. This study opens the door for a detailed mechanistic elucidation of the early steps of lanthanide complex-peptide or lanthanide complex-protein interaction or self-assembly processes.

Luminescent lanthanide(III) complexes of DTPA-bis(amido-phenyl-terpyridine) for bioimaging and phototherapeutic applications

We report here a series of coordinatively-saturated and thermodynamically stable luminescent [Ln(dtntp)(H₂O)] [Ln(III) = Eu (1), Tb (2), Gd (3), Sm (4) and Dy (5)] complexes using an aminophenyl-terpyridine appended-DTPA (dtntp) chelating ligand as cell imaging and photocytotoxic agents. The N,N″-bisamide derivative of H₅DTPA named as dtntp is based on 4'-(4-aminophenyl)-2,2':6',2″-terpyridine conjugated to diethylenetriamine-N,N',N″-pentaacetic acid. The structure, physicochemical properties, detailed photophysical aspects, interaction with DNA and serum proteins, and photocytotoxicity were studied. The intrinsic luminescence of Eu(III) and Tb(III) complexes due to f → f transitions used to evaluate their cellular uptake and distribution in cancer cells. The solid-state structure of [Eu(dtntp)(DMF)] (1·DMF) shows a discrete mononuclear molecule with nine-coordinated {EuN₃O₆} distorted tricapped-trigonal prism (TTP) coordination geometry around the Eu(III). The {EuN₃O₆} core results from three nitrogen atoms and three carboxylate oxygen atoms, and two carbonyl oxygen atoms of the amide groups of dtntp ligand. The ninth coordination site is occupied by an oxygen atom of DMF as a solvent from crystallization. The designed probes have two aromatic pendant phenyl-terpyridine (Ph-tpy) moieties as photo-sensitizing antennae to impart the desirable optical properties for cellular imaging and photocytotoxicity. The photostability, coordinative saturation, and energetically rightly poised triplet states of dtntp ligand allow the efficient energy transfer (ET) from Ph-tpy to the emissive excited states of the Eu(III)/Tb(III), makes them luminescent cellular imaging probes. The Ln(III) complexes show significant binding tendency to DNA (K ~ 10⁴ M^-1), and serum proteins (BSA and HSA) (K ~ 10⁵ M^-1). The luminescent Eu(III) (1) and Tb(III) (2) complexes were utilized for cellular internalization and cytotoxicity studies due to their optimal photophysical properties. The cellular uptake studies using fluorescence imaging displayed intracellular (cytosolic and nuclear) localization in cancer cells. The complexes 1 and 2 displayed significant photocytotoxicity in HeLa cells. These results offer a modular design strategy with further scope to utilize appended N,N,N-donor tpy moiety for developing light-responsive luminescent Ln(III) bioprobes for theranostic applications.

Two new lanthanide complexes with 5-(Pyrazol-1-yl)nicotinic acid: Structures and their anti-cancer properties

Two new lanthanide complexes [PrL₂(EA)₂]NO₃ (complex 1) and [SmL₂(EA)₂]NO₃ (complex 2) (H₂L = 5-(Pyrazol-1-yl)nicotinic acid, EA = CH₃CH₂OH) were synthesized. The structures were characterized by single crystal X-ray and elemental analysis. The interaction between the complex and fish sperm DNA(FS-DNA) was monitored using ultraviolet and fluorescence spectroscopy, and the binding constants were determined. Both complexes showed the ability to effectively bind DNA, and the molecular docking technology was used to simulate the binding of the complex and DNA. In addition, through the annexin V-Fluorescein Isothiocyanate(FITC)/ Propidium Iodide (PI) test experiment, tetrazollium [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT) in vitro test, and cell morphology apoptosis studies, it was shown that the complex can effectively induce HeLa tumor cell apoptosis. Compared with cisplatin and complex, complex 1 shows significant cancer cell inhibition, and we hope that this new type of complex will open up new ways for the next generation of drugs in biomedical applications.

Synthesis, characterization, and biological applications of pyrazole moiety bearing osmium(IV) complexes

Osmium (IV) complexes with pyrazole nucleus containing ligands were synthesized. Os(IV) compounds were characterized using ESI-MS, ICP-OES, IR spectroscopy, electronic spectroscopy, conductance, and magnetic measurements. Whereas, ligands were characterized by heteronuclear spectroscopy, (¹H and ¹³C), IR spectroscopy, and elemental analysis. All the compounds were tested for their potential to interact with HS-DNA by absorption titration, fluorescence spectroscopy, viscosity measurement, and docking study. The quenching constant and Stern Volmer constant values were calculated using fluorescence study. The synthesized compounds were studied for in-vitro bacteriostatic and cytotoxic activities. The cancer cell line studies of all the synthesized complexes were carried out on human lung cancer cells (A549).Supplemental data for this article is available online at https://doi.org/10.1080/15257770.2021.1921795 .

A Phosphatase-Mimetic Nano-Stabilizer of Mast Cells for Long-Term Prevention of Allergic Disease

Allergic diseases are pathological immune responses with significant morbidity, which are closely associated with allergic mediators as released by allergen-stimulated mast cells (MCs). Prophylactic stabilization of MCs is regarded as a practical approach to prevent allergic diseases. However, most of the existing small molecular MC stabilizers exhibit a narrow therapeutic time window, failing to provide long-term prevention of allergic diseases. Herein, ceria nanoparticle (CeNP-) based phosphatase-mimetic nano-stabilizers (PMNSs) with a long-term therapeutic time window are developed for allergic disease prevention. By virtue of the regenerable catalytic hotspots of oxygen vacancies on the surface of CeNPs, PMNSs exhibit sustainable phosphatase-mimetic activity to dephosphorylate phosphoproteins in allergen-stimulated MCs. Consequently, PMNSs constantly modulate intracellular phospho-signaling cascades of MCs to inhibit the degranulation of allergic mediators, which prevents the initiation of allergic mediator-associated pathological responses, eventually providing protection against allergic diseases with a long-term therapeutic time window.

In vitro selection and application of lanthanide-dependent DNAzymes

Highly sensitive and selective detection of lanthanide ions is a major analytical challenge. In recent years, the use of DNA for this purpose has been pursued. For such highly charged cations, it is difficult to select their aptamers due to strong nonspecific binding. On the other hand, the use of catalytic DNA or DNAzymes has an advantage to overcome this problem, especially DNAzymes with RNA-cleaving activity. In this chapter, a few such DNAzymes are introduced and methods for in vitro selection of lanthanide-dependent RNA-cleaving DNAzymes are described in detail, including the selection protocols, the DNA sequences used, the characterization of selected DNAzymes and their conversion into biosensors. All of the experiments use only fluorophore-labeled DNA, and radioisotope labeling is completely avoided. The resulting DNAzymes can distinguish lanthanides from non-lanthanide metals, tell the difference between light and heavy lanthanides, and can be used together to discriminate individual lanthanides.

Structural Characterization, Magnetic and Luminescent Properties of Praseodymium(III)-4,4,4-Trifluoro-1-(2-Naphthyl)Butane-1,3-Dionato(1-) Complexes

Four new Pr(III) mononuclear complexes of formula [Pr(ntfa)3(MeOH)2] (1), [Pr(ntfa)3(bipy)2] (2), [Pr(ntfa)3(4,4′-Mt2bipy)] (3) and [Pr(ntfa)3(5,5′-Me2bipy)] (4), where ntfa = 4,4,4-trifuoro-1-(naphthalen-2-yl)butane-1,3-dionato(1-), 5,5′-Me2bipy = 5,5′-dimethyl-2,2′-dipyridine, 4,4′-Mt2bipy = 4,4′-dimethoxy-2,2′-dipyridine, have been synthesized and structurally characterized. The complexes display the coordination numbers 8 for 1, 3 and 4, and 10 for 2. Magnetic measurements of complexes 1–4 were consistent with a magnetically uncoupled Pr3+ ion in the 3H4 ground state. The solid state luminescence studies showed that the ancillary chelating bipyridyl ligands in the 2–4 complexes greatly enhance the luminescence emission in the visible and NIR regions through efficient energy transfer from the ligands to the central Pr3+ ion; behaving as “antenna” ligands.

A high local DNA concentration for nucleating a DNA/Fe coordination shell on gold nanoparticles

Preparing DNA/Fe coordination nanoparticles in solution requires a high concentration of DNA. Herein we grew a DNA/Fe shell on DNA-functionalized gold nanoparticles. Taking advantage of the high local DNA density, the required DNA concentration decreased 60-fold, and the size can be controlled. This hybrid material allowed drug loading and colorimetric sensing.

Thermodynamic and Spectroscopic Studies of the Complexes Formed in Tartaric Acid and Lanthanide(III) Ions Binary Systems

Binary complexes of tartaric acid with lanthanide(III) ions were investigated. The studies have been performed in aqueous solution using the potentiometric method with computer analysis of the data for detection of the complexes set, determination of the stability constants of these compounds. The mode of the coordination of complexes found was determined using spectroscopy, which shows: Infrared, circular dichroism, ultraviolet, visible as well as luminescence spectroscopy. The overall stability constants of the complexes as well as the equilibrium constants of the reaction were determined. Analysis of the equilibrium constants of the reactions and spectroscopic data allowed the effectiveness of the carboxyl groups in the process of complex formation.

New coordination compounds of citric acid and polyamines with lanthanide ions - potential application in monitoring the treatment of cancer diseases

Non-covalent interaction in the binary systems of polyamines (putrescine, spermidine, spermine) with citric acid and complex formation in the binary as well as ternary systems of lanthanide(III) ions, citric acid and polyamine have been investigated. The studies were performed in aqueous solution. The overall stability constants of the complexes were determined using the potentiometric method with computer analysis of the data. Only mononuclear type of complexes were found in the ternary systems and polyamines were located in the outer as well as inner coordination sphere. Non-covalent interaction between biogenic amines and citric acid in the binary and ternary systems were confirmed on the basis of the equilibrium constants analysis and spectroscopic studies.