The development of magnetic resonance imaging (MRI) contrast agents is important to human health given the increasing importance of MRI diagnostics. An important new development in this area is based on the discovery of Ln(lll) complexes that function as MRI contrast agents by chemical exchange saturation transfer (CEST) processes. Unlike the more conventional Gd(lll) contrast agents, Ln(lll) CEST agents may contain almost any of the paramagnetic Ln(lll). In order to develop more effective contrast agents, it is important to study Ln(lll) coordination chemistry including water ligand exchange rates, coordination number and variations across the Ln(lll) series. ? ? The goal of the proposed research is to use direct-excitation (non-ligand sensitized) luminescence spectroscopy of Nd(lll), Sm(lll), Eu(lll), Dy(lll) and Yb(lll) to study the coordination chemistry of Ln(lll) contrast agents. A new laser system set up at the University of Buffalo, will be used for this work. There are three major research objectives including: 1) to determine the conditions for the direct-excitation luminescence of Nd(lll), Sm(lll), Eu(lll), Dy(lll) and Yb(lll) complexes and quantitate selected ligand group excited state quenching constants, 2) to utilize the short luminescence lifetimes of Sm(lll), Dy(lll) and Yb(lll) to study a dynamic equilibrium between eight and nine coordinate Ln(lll) complexes and to obtain rate constants for ligand exchange for Eu(lll) complexes, 3) to evaluate the potential of mononuclear Ln(lll) macrocyclic complexes containing pendent alcohol groups and dinuclear Ln(lll) complexes as MRI contrast agents. This work will contribute to a better basic understanding of Ln(lll) coordination chemistry and will yield new tools for Ln(lll) research in biological and chemical systems. The new laser system will also be available to researchers throughout the country and will be at the heart of a center for Ln(lll) luminescence research. ? ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Biomedical Imaging and Bioengineering (NIBIB)
Type
Small Research Grants (R03)
Project #
5R03EB004609-02
Application #
7097953
Study Section
Special Emphasis Panel (ZRG1-MI (01))
Program Officer
Zhang, Yantian
Project Start
2005-08-01
Project End
2008-07-31
Budget Start
2006-08-01
Budget End
2008-07-31
Support Year
2
Fiscal Year
2006
Total Cost
$76,061
Indirect Cost
Name
State University of New York at Buffalo
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
038633251
City
Buffalo
State
NY
Country
United States
Zip Code
14260
Hammell, Jacob; Buttarazzi, Leandro; Huang, Ching-Hui et al. (2011) Eu(III) complexes as anion-responsive luminescent sensors and paramagnetic chemical exchange saturation transfer agents. Inorg Chem 50:4857-67
Dorazio, Sarina J; Tsitovich, Pavel B; Siters, Kevin E et al. (2011) Iron(II) PARACEST MRI contrast agents. J Am Chem Soc 133:14154-6
Huang, Ching-Hui; Hammell, Jacob; Ratnakar, S James et al. (2010) Activation of a PARACEST agent for MRI through selective outersphere interactions with phosphate diesters. Inorg Chem 49:5963-70
Huang, Ching-Hui; Morrow, Janet R (2009) Cerium(III), europium(III), and ytterbium(III) complexes with alcohol donor groups as chemical exchange saturation transfer agents for MRI. Inorg Chem 48:7237-43
Nwe, Kido; Andolina, Christopher M; Huang, Ching-Hui et al. (2009) PARACEST properties of a dinuclear neodymium(III) complex bound to DNA or carbonate. Bioconjug Chem 20:1375-82
Huang, Ching-Hui; Morrow, Janet R (2009) A PARACEST agent responsive to inner- and outer-sphere phosphate ester interactions for MRI applications. J Am Chem Soc 131:4206-7
Woods, Mark; Woessner, Donald E; Zhao, Piyu et al. (2006) Europium(III) macrocyclic complexes with alcohol pendant groups as chemical exchange saturation transfer agents. J Am Chem Soc 128:10155-62