Daniel Calle1, Arisbel Cerpa2, Viviana Negri, 13, Elisabetta Agostinelli4, Sebastin Cerdn5, Sara Laureti4, Paloma Ballesteros3, Gaspare Varvaro4
1Instituto de Investigaciones Biomdicas "Alberto Sols", Madrid, Spain; 2Universidad Europea de Madrid, Villaviciosa de Odn, Madrid, Spain; 3Universidad Nacional de Educacin a Distancia, Madrid, Spain; 4Istituto di Struttura della Materia, Monterotondo, Rome, Italy; 5Instituto de Investigaciones Biomdicas - CSIC, Madrid, Spain
The relaxation of water molecules induced by classical contrast agents occurs in an isotropic manner, becoming not possible to determine the molecular orientation of the contrast agent molecule from water relaxivity measurements. In this work we report on a novel family of contrast agents endowed naturally with anisotropic relaxivity (1,2) and thus able to reveal the molecular orientation of the contrast agent probe from non invasive, water relaxivity measurements. Single Walled Carbon Nanotubes (SWCNTs) preparations are shown to be useful systems for this purpose since they align along the magnetic field and may depict different magnetic properties in the longitudinal and axial directions. In this communication we report, for the first time to our knowledge, measurements of the directional magnetic susceptibility of SWCNTs suspensions using a SQUID magnetometer and of the resulting anisotropic water relaxivity using an MRI scanner.