Nano Lett. 2012, 12, 3127−3131

Water-Dispersible Ferrimagnetic Iron Oxide Nanocubes with Extremely High r2 Relaxivity for Highly Sensitive in Vivo MRI of Tumors Nohyun Lee,†,§ Yoonseok Choi,‡,§ Youjin Lee,† Mihyun Park,† Woo Kyung Moon,‡ Seung Hong Choi,*,‡ and Taeghwan Hyeon*,† †World Class University Program of Chemical Convergence for Energy and Environment, Institute of Chemical Processes, and School of Chemical and Biological Engineering, Seoul National University, Seoul, 151-744, Korea ‡Diagnostic Radiology, Seoul National University Hospital, and the Institute of Radiation Medicine, Medical Research Center, Seoul National University, 28, Yeongeon-dong, Jongno-gu, Seoul, 110-744, Korea