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2007-01-01 - Colloque/Présentation - poster - Anglais - 1 page(s)

Henoumont Céline , Henrotte Virginie, Laurent Sophie , Vander Elst Luce , Muller Robert , "Synthesis and physicochemical characterization of a new potential MRI reporter. Investigation of its non covalent interaction with human serum albumin" in European Society for molecular imaging, Second International Conference (ESMI), Naples, Italie, 2007

  • Codes CREF : Résonance magnétique nucléaire (biophysique) (DI131B), Chimie de coordination (DI1319), Chimie organique (DI1313)
  • Unités de recherche UMONS : Chimie générale, organique et biomédicale (M108)
  • Instituts UMONS : Institut des Sciences et Technologies de la Santé (Santé), Institut des Biosciences (Biosciences)

Abstract(s) :

(Anglais) The synthesis and the physicochemical characterization of a new gadolinium MRI contrast agent (Gd-C4-sulfaphenazol-DTPA) showing a strong affinity for human serum albumin (HSA) is reported. The measurements reveal a relaxivity in water of 7.8 s-1 mM-1 at 0.47 T and 310 K, a fast water exchange and a good stability versus zinc transmetallation. The investigation of the interaction with HSA was performed with three different techniques : proton relaxivity, mass spectrometry and NMR diffusometry. The relaxometry technique shows an apparent relaxivity of ca 24 s-1 mM-1 for a 1 mM solution of the complex in the presence of HSA 4%. The calculated association constant is ca 9000 M-1 with 3 binding sites. Mass spectra of the paramagnetic complex confirm its high affinity for the protein and show that at least 3 binding sites exist. Competition experiments with ibuprofen (Suddlow site II of HSA) and salicylic acid (Suddlow site I of HSA), were carried out by NMR diffusometry. In these experiments, the diffusion coefficient of ibuprofen (10 mM) or salicylic acid (10 mM) was measured in the presence of the europium complex (2 mM) and HSA 4% (buffered solutions). The results show that the presence of the Eu-complex increases markedly the diffusion coefficient of ibuprofen but has little effect on salicylic acid, indicating that the paramagnetic molecule interacts with the Suddlow site II of HSA. This new reporter is thus promising and further in vivo experiments will be undertaken in a near future.