Mingqian Tan1, Eun-Kee Jeong2, Zheng-Rong Lu1
1Case Western Reserve University, Cleveland, OH, United States; 2University of Utah, Salt Lake City, UT, United States
A peptide targeted nanoglobular Mn(II)-DOTA conjugate was designed and synthesized as MRI contrast agent for cancer molecular imaging. The target specific contrast agent comprised of 2 peptides and 42 Mn(II) chelates on the surface of the G3 nanoglobule with a defined structure. The T1 and T2 relaxivities at room temperature are 3.13 and 8.14 mM-1sec-1 per Mn(II) chelate at 3T, respectively. The targeted nanoglobular contrast agent specifically bound to tumor tissue and resulted in significant tumor contrast enhancement in tumor-bearing mice as compared to a non-targeted control at a dose as low as 0.03 mmol-Mn/kg .