Preparation of Polymer-Supported Polyazamacrocycles. The Role of the Polymeric Matrix in the Preparation of Polymer-Supported Polyazamacrocycles

Different approaches have been studied for the preparation of resins containing different polyazamacrocycles. Preparation of monolithic resins by polymerization of vinylic derivatives of the corresponding macrocycles is shown to be a more versatile strategy for this purpose. The use of energy-dispersive analysis by X-ray has revealed to be a very useful tool for the rapid evaluation of the interaction of those materials with both anions and cations and has allowed the corresponding selectivity trends to be obtained in a fast and simple way. Important effects of the polymeric matrix are observed in some cases.

Modulation of DNA binding by reversible metal-controlled molecular reorganizations of scorpiand-like ligands.

DNA interaction with scorpiand azamacrocycles has been achieved through modulation of their binding affinities. Studies performed with different experimental techniques provided evidence that pH or metal-driven molecular reorganizations of these ligands regulate their ability to interact with calf thymus DNA (ctDNA) through an intercalative mode. Interestingly enough, metal-driven molecular reorganizations serve to increase or decrease the biological activities of these compounds significantly.

One-pot preparation of surface modified boehmite nanoparticles with rare-earth cyclen complexes.

We report on the one-pot synthetic procedure of cyclen derivatives bearing three acetate groups attached on boehmite nanoparticles, the complexing capabilities of these inorganic–organic hybrid materials with rare earth cations, and the behaviour as contrast agents or fluorescence probes. Delgado Pinar, Estefania, Estefania.Delgado@uv.es ; Frias Martinez, Juan Carlos, Juan.Frias@uv.es ; Albelda Gimeno, Maria Teresa, Teresa.Albelda@uv.es ; Alarcon Navarro, Javier, Javier.Alarcon@uv.es ; Garcia-España Monsonis, Enrique, Enrique.Garcia-Es@uv.es

Preparation of Hg2+ selective fluorescent chemosensors based on surface modified core–shell aluminosilicate nanoparticles

A synthetic procedure for the preparation of functional structured inorganic–organic hybrid materials consisting of boehmite-silica core–shell nanoparticles and anthracene-containing amines covalently attached to the nanoparticles surface is reported. The system functionalised with the monoamine chain shows a very high sensing performance for Hg2+ detection in pure water reaching a detection limit of 0.2 ppb. Two additional advantages of these systems are their stability over a wide pH window and the feasibility to be recovered by a simple procedure.

Modified lipoproteins as contrast agents for imaging of atherosclerosis.

The ability to detect and characterize atherosclerosis with targeted contrast agents may enable initiation of therapy for atherosclerotic lesions prior to becoming symptomatic. Since lipoproteins such as high-density lipoprotein (HDL) and low-density lipoprotein (LDL) play a critical role in the regulation of plaque biology through the transport of lipids into and out of atherosclerotic lesions, modifying HDL and LDL with radioisotopes for nuclear imaging, chelates for magnetic resonance imaging (MRI) or other possible contrast agents for computed tomography imaging techniques may aid in the detection and characterization of atherosclerosis. This review focuses on the literature employing l…

Macrophage-Specific Lipid-Based Nanoparticles Improve Cardiac Magnetic Resonance Detection and Characterization of Human Atherosclerosis

ObjectivesWe sought to determine whether gadolinium (Gd)-containing lipid-based nanoparticles (NPs) targeting the macrophage scavenger receptor-B (CD36) improve cardiac magnetic resonance (CMR) detection and characterization of human atherosclerosis.BackgroundGd-containing lipid-based NPs targeting macrophages have improved MR detection of murine atherosclerosis.MethodsGadolinium-containing untargeted NPs, anti-CD36 NPs, and nonspecific Fc-NPs were created. Macrophages were incubated with fluorescent targeted and nontargeted NPs to determine uptake via confocal microscopy and inductively coupled plasma mass spectroscopy (ICP-MS) quantified Gd uptake. Human aortic specimens were harvested at…

Anti-angiogenic drug loaded liposomes: Nanotherapy for early atherosclerotic lesions in mice.

Este artículo se encuentra disponible en la página web de la revista en la siguiente URL: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0190540 También participan en la elaboración de este artículo científico: Aracely Calatayud-Pascual, Alicia López-Castellano, Elena P. Albelda, Enrique García-España, Luis Martí-Bonmatí, Juan C. Frias y M. Teresa Albelda. Fumagillin-loaded liposomes were injected into ApoE-KO mice. The animals were divided into several groups to test the efficacy of this anti-angiogenic drug for early treatment of atherosclerotic lesions. Statistical analysis of the lesions revealed a decrease in the lesion size after 5 weeks of treatment.

Acid–base properties of functionalised tripodal polyamines and their interaction with nucleotides and nucleic acids

Novel, highly positively charged tripodal polyamines with appended heterocyclic moieties revealed an intriguing panel of protonation species within the biologically relevant range. Studied compounds bind nucleotide monophosphates by mostly electrostatic interactions but only the imidazole analogue showed selectivity toward UMP in respect to other nucleotides. Strong binding of all the studied compounds to both ds-DNA and ds-RNA is to some extent selective toward the latter, showing rather rare RNA over DNA preference.

Guest-Induced Selective Functionalization of Polyaza[n]paracyclophanes

A new strategy to the preparation of selectively functionalized polyazamacrocycles is presented. Polyaza[n]paracyclophane receptors are able to efficiently direct their own selective functionalization upon interaction with simple guests such as metal cations. This enables the preparation of novel receptors functionalized at one of the benzylic nitrogen atoms with a variety of groups. Selective difunctionalization at both benzylic positions can also be achieved in this way.

Lanthanide complexes as imaging agents anchored on nano-sized particles of boehmite

International audience; The synthesis of boehmite nanoparticles modified with lanthanides (Eu, Tb and Gd) is described. Their synthesis, characterization and in vitro assays with HeLa cells were performed. The nuclear magnetic relaxation dispersion (NMRD) profiles of the two chelating moieties were studied. Imaging data from laser scanning confocal fluorescence microscopy and flow cytometry revealed that the nanoscaffolds were taken up by the cells, distributed throughout the cytoplasm and showed no toxicity. This platform could represent an alternative to silica-based inert matrices as imaging vehicles.

Nanoparticles as Contrast Agents for MRI of Atherosclerotic Lesions

Nanoparticle contrast agents for MRI may aid in identifying atherosclerotic lesions that give rise to ischemic events by means of penetration and retention in the plaque. These imaging agents may provide valuable information regarding plaque characteristics which can help determine the risk of plaque rupture. By increasing molecular flexibility or adding a means of specifically targeting ligands via antibody or peptide, nanoparticles can enhance certain regions of the atherosclerotic plaque. The development of single contrast agents detectable with multiple imaging modalities may further improve our ability to detect and characterize atherosclerosis in clinical and preclinical applications.…

New Insight to the Chemistry of Polyaza[n]paracyclophanes. A 15N NMR Study

Synthesis and coordination properties of an azamacrocyclic Zn(II) chemosensor containing pendent methylnaphthyl groups

The synthesis of a polyazamacrocycle constituted by two diethylenetriamine bridges functionalized at their central nitrogen with naphth-2-ylmethyl units and interconnected through 2,6-dimethylpyridine spacers (L1) is reported. The protonation behaviour of the new macrocycle in water and in water-ethanol 70/30 v/v mixed solvent has been examined by means of pH-metric, UV-Vis and steady-state fluorescence techniques. The fluorescence emission is slightly quenched following the deprotonation of the central tertiary amines and more deeply quenched upon deprotonation of the secondary amino groups. pH-Metric titrations show that in water-ethanol 70/30 v/v L1 forms stable mononuclear complexes wit…

Binding Mode and Selectivity of a Scorpiand-Like Polyamine Ligand to Single- and Double-Stranded DNA and RNA: Metal- and pH-Driven Modulation

The interaction of a polyazacyclophane ligand having an ethylamine pendant arm functionalized with an anthryl group (L), with the single-stranded polynucleotides polyA, polyG, polyU, and polyC as well as with the double-stranded polynucleotides polyA-polyU, poly(dAT)(2), and poly(dGC)(2) has been followed by UV/Vis titration, steady state fluorescence spectroscopy, and thermal denaturation measurements. In the case of the single-stranded polynucleotides, the UV/Vis and fluorescence titrations permit to distinguish between sequences containing purine and pyrimidine bases. For the double-stranded polynucleotides the UV/Vis measurements show for all of them hypochromicity and bathochromic shif…

Advances in detection and characterization of atherosclerosis using contrast agents targeting the macrophage

With advances in imaging technology and our understanding of the role of inflammation in atherosclerosis, the macrophage appears to be an excellent target for imaging the progression of disease. In addition to imaging the macrophage with only 1 modality, contrast agents can be created that can be imaged with multiple modalities. This seems extremely attractive, as lesion morphology and characteristics can be determined with modalities that provide high picture resolution, such as CT or MRI, whereas macrophage quantity can be accurately determined through the creation of a radiolabeled contrast agent such as FDG via PET. Although this combination of imaging technologies may yield clinically …

A bibracchial lariat aza-crown ether as an abiotic catalyst of malonic acid enolization

A bibracchial lariat aza-crown ether (L) consisting of 2-aminoethylnaphthyl moieties appended to a 2 : 2 azapyridinophane structure displays significant activation of H–D exchange in malonic acid. The compound forms very stable adducts with malonate anions (MA) in the 2–10 pH range. Molecular dynamics studies performed for the species resulting from the interaction of the hexaprotonated macrocycle and the dianion show that malonate is encapsulated by L with distances between the CH2 group of malonate and the pyridine nitrogens of ca. 3.5 A. The pendant arms of L cap above and below the anion, defining a pseudo-cage structure. Quantum chemical calculations for α-proton abstraction from malon…

A remarkable selectivity in the N-functionalization of polyaza[n]paracyclophanes. Synthesis of N-(4-picolyl)-substituted 2,6,9,13-tetraaza[14]paracyclophanes

Abstract Interaction of cationic host species, in particular Zn 2+ salts, with polyaza[n]paracyclophanes (i.e. 2,6,9,13-Tetraaza[14]paracyclophane, B323 (1a) ) directs their selective N-functionalization. In this way compounds mono- or difunctionalized with ArCH 2− groups at the benzylic nitrogen atoms can be easily obtained. Direct reaction with the alkylating agent, in the absence of the Zn 2+ species, produces, in general, very complex mixtures of mono- and polyalkylated compounds except when 4-picolyl chloride is used. In this case, mono-, di-, tri- and tetra N-substituted derivatives of D323 can be isolated depending on the amount of the alkylating agent used. In this case, the mono- a…

CCDC 1884191: Experimental Crystal Structure Determination

Related Article: Juan C. Frías, José Soriano, Salvador Blasco, Enrique García-España, Aurora Rodríguez-Rodríguez, David Esteban-Gómez, Fabio Carniato, Mauro Botta, Carlos Platas-Iglesias, M. Teresa Albelda|2020|Inorg.Chem.|59|7306|doi:10.1021/acs.inorgchem.0c00690