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A new tetradentate ligand, namely 3,3′‐((1E,1′E)‐(ethane‐1,2‐diylbis(azaneylylidene))bis(methaneylylidene))bis(pyridin‐2‐amine) (en2ampy) was prepared and two copper(II) complexes, viz. [Cu(en2ampy)]Cl2 (1) and [Cu(en2ampy)](NO3)2 (2), were obtained through its reaction with copper(II) chloride and copper(II) nitrate, respectively. The single‐crystal X‐ray structure of the compounds showed that the metal centre was coordinated in a square‐planar fashion by a doubly deprotonated en2ampy acting as a tetradentate N2 ${{{\rm N}}_{2}}$ /N22- ${{{\rm N}}_{2}^{2-}}$ ‐donor ligand. DNA‐binding studies revealed that 1 and 2 were electrostatically binding to DNA, probably in the grooves and cytotoxicity assays showed that the complexes were clearly more efficient than cisplatin against ovarian carcinoma (A2780) cells and the cisplatin‐resistant (A2780Cis) ones. [ABSTRACT FROM AUTHOR]

New pyridine containing triAza; 3,6,9,15-tetraazabicyclo[9.3.1]pentadeca-1(15),11,13-triene-3,6,9-triacetic acid (PCTA) ligands presenting pendant carboxylic acid or alcohol functions have been synthesized and used to form diaqua Gd(III) complexes, which have been immobilized onto dense silica nanoparticles. Cytotoxicity studies of these complexes (free or immobilized on the nanoparticles) on normal 1BR3G cells and cancerous HCT 116 cells indicated a dependence on the pendant chemical group for the free complexes. However, this effect disappeared once the complexes were immobilized on the surface of the nanoparticles, leading to non-toxic nanomaterials. The interest of these complexes (free or immobilized on dense silica nanoparticles) as contrast agents in magnetic resonance imaging (MRI) has been evaluated in comparison with DOTAREM® by recording their nuclear magnetic resonance dispersion (NMRD) profiles, measuring their transversal and longitudinal relaxivities as well as recording images on phantoms at 37 °C. This study has evidenced the high potential of these complexes: first it suggested the possibility to reduce the dose to be injected by a factor of 10, second it evidenced their high efficiency in high field T1-weighted MRI (9.4 T), the key towards images of higher resolution and shorter acquisition times. [ABSTRACT FROM AUTHOR]

The growing concern over the toxicity of Gd-based contrast agents used in magnetic resonance imaging (MRI) motivates the search for less toxic and more effective alternatives. Among these alternatives, iron–iron oxide (Fe@FeOx) core-shell architectures have been long recognized as promising MRI contrast agents while limited information on their engineering is available. Here we report the synthesis of 10 nm large Fe@FeOx nanoparticles, their coating with a 11 nm thick layer of dense silica and functionalization by 5 kDa PEG chains to improve their biocompatibility. The nanomaterials obtained have been characterized by a set of complementary techniques such as infra-red and nuclear magnetic resonance spectroscopies, transmission electron microscopy, dynamic light scattering and zetametry, and magnetometry. They display hydrodynamic diameters in the 100 nm range, zetapotential values around −30 mV, and magnetization values higher than the reference contrast agent RESOVIST®. They display no cytotoxicity against 1BR3G and HCT116 cell lines and no hemolytic activity against human red blood cells. Their nuclear magnetic relaxation dispersion (NMRD) profiles are typical for nanomaterials of this size and magnetization. They display high r2 relaxivity values and low r1 leading to enhanced r2/r1 ratios in comparison with RESOVIST®. All these data make them promising contrast agents to detect early stage tumors. [ABSTRACT FROM AUTHOR]

The growing concern over the toxicity of Gd-based contrast agents used in magnetic resonance imaging (MRI) motivates the search for less toxic and more effective alternatives. Among these alternatives, iron-iron oxide (Fe@FeOx) core-shell architectures have been long recognized as promising MRI contrast agents while limited information on their engineering is available. Here we report the synthesis of 10 nm large Fe@FeOx nanoparticles, their coating with a 11 nm thick layer of dense silica and functionalization by 5 kDa PEG chains to improve their biocompatibility. The nanomaterials obtained have been characterized by a set of complementary techniques such as infra-red and nuclear magnetic resonance spectroscopies, transmission electron microscopy, dynamic light scattering and zetametry, and magnetometry. They display hydrodynamic diameters in the 100 nm range, zetapotential values around -30 mV, and magnetization values higher than the reference contrast agent RESOVIST ® . They display no cytotoxicity against 1BR3G and HCT116 cell lines and no hemolytic activity against human red blood cells. Their nuclear magnetic relaxation dispersion (NMRD) profiles are typical for nanomaterials of this size and magnetization. They display high r 2 relaxivity values and low r 1 leading to enhanced r 2 /r 1 ratios in comparison with RESOVIST ® . All these data make them promising contrast agents to detect early stage tumors., Competing Interests: The authors declare no conflict of interest.