192638-67-8Relevant academic research and scientific papers
Lanthanide(III) complexes of diethylenetriaminepentaacetic acid (DTPA)-bisamide derivatives as potential agents for bimodal (Optical/Magnetic Resonance) imaging
Debroye, Elke,Eliseeva, Svetlana V.,Laurent, Sophie,Vander Elst, Luce,Petoud, Stephane,Muller, Robert N.,Parac-Vogt, Tatjana N.
, p. 2629 - 2639 (2013)
Diethylenetriaminepentaacetic acid (DTPA)-bisamide derivatives functionalized with p-toluidine, 6-aminocoumarin, 1-naphthalene methylamine and 4-ethynylaniline were synthesized and fully characterized by mass spectrometry, NMR spectroscopy, FTIR spectroscopy and elemental analysis. LnIII complexes (Ln = Gd, Eu, Tb, Y) of the ligands DTPA-bis-p-toluidineamide (DTPA-BTolA), DTPA-bis-6-coumarinamide (DTPA-BCoumA), DTPA-bis-1- naphthylmethylamide (DTPA-BNaphA) and DTPA-bis-4-ethynylphenylamide (DTPA-BEthA) were prepared and studied for their bimodal magnetic resonance imaging/optical properties. EuIII and TbIII derivatives in aqueous solutions exhibit characteristic red and green emission, respectively, with quantum yields of 0.73 % for EuIII-DTPA-BNaphA and 2.5 % for Tb III-DTPA-BEthA. Ligand-centred photophysical properties of the GdIII complexes were investigated to gain insight into energy-transfer processes that take place in these systems. The GdIII complexes were also analyzed by nuclear magnetic relaxation dispersion (NMRD) techniques. The relaxivity (r1) at 20 MHz and 310 K equals 4.1 s -1 mM-1 for Gd-DTPA-BTolA, 5.1 s-1 mM -1 for Gd-DTPA-BCoumA, 6.4 s-1 mM-1 for Gd-DTPA-BNaphA and 5.7 s-1 mM-1 for Gd-DTPA-BEthA. These values are higher than the value of 3.8 s-1 mM-1 for Gd-DTPA (Magnevist). The improved relaxivity is due to the increase in the rotational tumbling time τR with a factor of 1.6 for Gd-DTPA-BTolA, 2.1 for Gd-DTPA-BCoumA, 3.1 for Gd-DTPA-BNaphA and 6.5 for Gd-DTPA-BEthA. In a 4 % human serum albumin solution, the apparent relaxivity at 20 MHz increases to values of 13.9 and 19.1 s-1 mM-1 for Gd-DTPA-BNaphA and Gd-DTPA-BEthA, respectively. All these features assist the search for optimal bimodal optical and magnetic resonance imaging probes. Copyright
