High relaxivity Mn(2+)-based MRI contrast agents.
Stable Mn(2+) mono- and binuclear complexes containing pentadentate 6,6'-((methylazanediyl)bis(methylene))dipicolinic acid coordinating units give remarkably high relaxivities due to the presence of two inner-sphere water molecules. The mononuclear derivative binds human serum albumin (HSA) with an association constant of 3372 M(-1), which results in the replacement of the coordinated water molecules by donor atoms of protein residues. The dinuclear analogue also binds HSA while leaving one of the Mn(2+) centres exposed to the solvent with two coordinated water molecules. Thus, this complex shows remarkably high relaxivities upon protein binding (39.0 mM(-1)  s(-1) per Mn, at 20 MHz and 37 °C).
Departamento de Química Fundamental, Universidade da Coruña, Campus da Zapateira, Rúa da Fraga 10, 15008 A Coruña (Spain).
Martín
M
Regueiro-Figueroa
Gabriele A
GA
Rolla
David
D
Esteban-Gómez
Andrés
A
de Blas
Teresa
T
Rodríguez-Blas
Mauro
M
Botta
Carlos
C
Platas-Iglesias
D003287:Contrast Media / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008345:Manganese / Q000737:chemistry*; D011485:Protein Binding; D012709:Serum Albumin / Q000737:chemistry*
D003287:Contrast Media; D056831:Coordination Complexes; D012709:Serum Albumin; D008345:Manganese
NMR imaging; contrast agents; coordination compounds; human serum albumin; manganese