Hydrothermal synthesis of a highly sensitive T2-weigthed MRI contrast agent: zinc-doped superparamagnetic iron oxide nanocrystals.

A highly efficient hydrothermal strategy for the synthesis of zinc-doped superparamagnetic iron oxide nanocrystals (SPION:Zn) with lower toxicity and improved sensitivity has been demonstrated. The saturation magnetizations of as-synthesized SPION:Zn were demonstrated to be Zn-dependent and could be tuned from 41.88 emu/g to 79.23 emu/g by changing the amount of Zn. As-synthesized hydrophobic SPION:Zn could be efficiently transferred into water phase through a ultrasonic process with the assistance of cetyltrimethylammonium bromide (CTAB) surfactant. As-obtained CTAB stabilized SPION:Zn was exploited as a MR enhanced contrast agent, and its T2 relaxivity coefficient (r2) was found to be as high as 342.09 mM(-1)s(-1).