Cu²⁺-Responsive Bimodal (Optical/MRI) Contrast Agent for Cellular Imaging

A water-soluble T₁ magnetic resonance imaging contrast agent (<b>1</b>) has been synthesized. The bimodal contrast agent <b>1</b> responds to the Cu²⁺ ion in living cells by enhancing the MRI modality signal whereas the optical signal gradually drops. This dual modality probe response depends on the cellular free copper ions in RAW 264.7 cells even at the micromolar level