Search results for "Relaxivity"
showing 5 items of 5 documents
Synthèse de nouveaux agents bimodaux hydrosolubles pour l'IRM, l'imagerie nucléaire, l'imagerie biphotonique et la génération de second harmonique
2015
The goal of my PhD studies was to synthesize new compounds for possible medical imaging applications. The first part of my thesis focused on the synthesis of heteroleptic ligands to achieve the chelation of two different metals aimed at addressing two types of medical imaging. We first synthesized porphyrins, which are well-known for the chelation of numerous transition metals. We focused on copper, whose copper-64 isotope is a β+ emitter usable in Positron Emission Tomography (PET). These porphyrins have been coupled with a DOTA derivative. This molecule, metallated with gadolinium, is well-known in Magnetic Resonance Imaging (MRI). Our compounds display encouraging relaxivities for MRI ap…
Elaboration of functionalized nanoparticles : applications as MRI contrast agent
2010
Spinel structured iron oxide nanoparticles open the way of biomedical applications of nanomaterials.Superparamagnetic properties of ten nanometer size crystallites permit to use them in diagnosis such as Magnetic Resonance Imaging (MRI).The aim of this work was to synthesize colloidal suspension of magnetite or maghemite (called USPIO for Ultrasmall SuperParamagnetic Iron Oxide) stable in physiological conditions (pH = 7.4 and [NaCl] = 0.15M).By classical co-precipitation method, UPSIO were synthesized with a mean crystallite size of 8 nm, with a specific surface area of 110 m².g-1 and an aggregate size of 20 nm. To stabilize these nano-objects, two ways were investigated. Electrostatic age…
Lanthanide complexes as imaging agents anchored on nano-sized particles of boehmite
2011
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.
A Gadolinium(III) Complex Based on the Thymine Nucleobase with Properties Suitable for Magnetic Resonance Imaging
2021
The paramagnetic gadolinium(III) ion is used as contrast agent in magnetic resonance (MR) imaging to improve the lesion detection and characterization. It generates a signal by changing the relaxivity of protons from associated water molecules and creates a clearer physical distinction between the molecule and the surrounding tissues. New gadolinium-based contrast agents displaying larger relaxivity values and specifically targeted might provide higher resolution and better functional images. We have synthesized the gadolinium(III) complex of formula [Gd(thy)2(H2O)6](ClO4)3·2H2O (1) [thy = 5-methyl-1H-pyrimidine-2,4-dione or thymine], which is the first reported compound based on gadolinium…
Porphyrines et tétraazamacrocycles dérivés du DOTA : association de deux ligands pour la chélation de métaux d'intérêt en imagerie médicale multimoda…
2012
The goal of my PhD thesis was to synthesize new molecules, which give access to heterobimetallic complexes with interesting properties for multimodal imaging. In this manuscript, several main points have been studied. The first part of this work concerns the synthesis and characterization of ligands. We describe here the synthesis of five new ligands based on the association of one porphyrin and one or several cyclen derivatives. Those ligands are water-soluble. During the synthesis, we have targeted improvements to our work and developed a new synthetic pathway, which allowed us to obtain one ligand incorporating a porphyrin, a cyclen derivative and a free amine function. This function cou…