Computational study of structural modifications to a novel class of paramagnetic chemical exchange saturation transfer (PARACEST) agents

PHYS 586

Whelton A. Miller III, wmiller@usip.edu1, Zhiwei Liu, z.liu@usip.edu2, and Vojislava Pophristic, v.pophri@usip.edu2. (1) Department of Chemistry & Biochemistry and West Center for Computational Chemistry and Drug Design, University of the Sciences in Philadelphia, 600 S 43rd St, Philadelphia, PA 19104, (2) West Center for Computational Chemistry and Drug Design, University of the Sciences in Philadelphia, Department of Chemistry & Biochemistry, 600 South 43rd Street, Philadelphia, PA 19104
Magnetic Resonance Imaging (MRI) is a non-invasive tool used by the medical community. Imaging agents, usually chelates, are used to enhance MRI signals. Our study focuses on the physical basis of MRI signal enhancement induced by structural modifications of a novel class of PARACEST agents. These agents work by modifying the magnetization transfer between the H2O molecule bound to the EuIII(DOTA) chelate and bulk water. We present here a computational study of the effect of chemical modifications of the para-substituents in the coordinating pendant arms on the CEST signal. This study attempts to reveal the origin of the substituent effect on the CEST signal and the electronic structure of the complex. The effect of simple electron-withdrawing and electron-donating substituents chemically attached to the chelate arms is quantified by correlating the experimental CEST signal with interactions in the coordinated water-chelate system computed from quantum mechanics.
 

PHYS Poster Session - Computational Spectroscopy and Reaction Dynamics
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster

Division of Physical Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008