A magnetic resonance imaging nanosensor for Hg (II) based on thymidine-functionalized supermagnetic iron oxide nanoparticles

A MRI nanosensor for Hg (II) was developed based on superparamagnetic iron oxide nanoparticles (SPIO NPs). The detection mechanism is attributed to Hg (II)-induced nanoassembly of thymidine-functionalized SPIO NPs from a dispersed to an aggregated state with a corresponding decrease in the transverse relaxation time (T2) of adjacent water protons. Furthermore, an enhancement of transverse relaxation rates (1/T2) showed the high selectivity for Hg (II) compared with other transition and main group metal ions.