Accueil > Publications > Recherche par années > Années 2000 > 2005

Tóth, E ; Bolskar, RD ; Borel, A ; González, G ; Helm, L ; Merbach, AE ; Sitharaman, B ; Wilson, LJ

Water-soluble Gadofullerenes : Toward High-relaxivity, pH-responsive MRI Contrast Agents

Journal of The American Chemical Society 127 (2) 799-805

par Administrateur - publié le

Abstract :

The water-soluble endohedral gadofullerene derivatives, Gd@C-60(OH)(x) and Gd@C-60[C(COOH)(2)](10), have been characterized with regard to their MRI contrast agent properties. Water-proton relaxivities have been measured in aqueous solution at variable temperature (278-335 K), and for the first time for gadofullerenes, relaxivities as a function of magnetic field (5 x 10(-4) to 9.4 T ; NMRD profiles) are also reported. Both compounds show relaxivity maxima at high magnetic fields (30-60 MHz) with a maximum relaxivity of 10.4 mM(-1) s(-1) for Gd@C-60[C(COOH)(2)](10) and 38.5 mM(-1) s(-1) for Gd@C-60(OH)(x) at 299 K. Variable-temperature, transverse and longitudinal 170 relaxation rates, and chemical shifts have been measured at three magnetic fields (B = 1.41, 4.7, and 9.4 T), and the results point exclusively to an outer sphere relaxation mechanism.