title: A R2/R1 ratiometric procedure for a concentration-independent, pH-responsive, Gd(III)-based MRI agent.
abstract: A novel procedure for making the pH responsiveness of a Gd-based probe independent of its concentration has been developed. The method is based on a ratiometric approach and requires the measurement, at magnetic fields higher than 1 T, of the paramagnetic contribution to the longitudinal and the transverse NMR relaxation rates of water protons in the presence of a Gd-based probe with a rotational mobility in the nanosecond time scale. The method has been tested and validated in vitro by using a macromolecular adduct based on the polyornithine backbone, whose rotational mobility is pH dependent. The results reported in this communication improve substantially the diagnostic potential of MRI responsive agents.
authors.affiliation: Dipartimento di Chimica IFM and Molecular Imaging Center, Via Pietro Giuria 7, I-10125 Torino, Italy. silvio.aime@unito.it
authors.forename: Silvio
authors.initials: S
authors.lastname: Aime
authors.forename: Franco
authors.initials: F
authors.lastname: Fedeli
authors.forename: Alberto
authors.initials: A
authors.lastname: Sanino
authors.forename: Enzo
authors.initials: E
authors.lastname: Terreno