Chang-Tong Yang1, Cai-Xian Yong1, Chew-Yuan Tuang2, Young-Tae Chang2, Kai-Hsiang Chuang1
1Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Agency for Science,Technology and Research, Singapore, Singapore; 2Laboratory of Bioimaging Probe Development, Singapore Bioimaging Consortium, Agency for Science,Technology and Research, Singapore, Singapore
We developed a new Gd(III) chelate by conjugating GdDO3A with 2-(diphenylphosphoryl)ethyldiphenylphosphonium cation -- Gd(DO3A-xy-TPEP)+ to form a cationic MRI contrast agent. This contrast agent has been synthesized and characterized in vitro and in vivo. In vitro cell viability showed insignificant cytotoxicity at low [Gd] concentrations up to 0.2 mM. The in vitro T1 relaxivity measured at 7.0 T is about 50% higher than that of clinically used Gd-DTPA and Gd-DOTA. In vivo imaging study in mice demonstrated longer tissue retention especially in the liver. It indicated that Gd(DO3A-xy-TPEP)+ could potentially be used to detect tumor which generally has larger negative mitochondrial transmembrane potential.