Synthesis and characterization of a smart contrast agent sensitive to calcium

A novel first-generation Ca2+ sensitive contrast agent, Gd-DOPTRA has been synthesized and characterized. The agent shows similar to 100% relaxivity enhancement upon addition of Ca2+. The agent is selective and sensitive to Ca2+ also in the presence of Mg2+ and Zn2+. The relaxivity studies carried out in physiological fluids prove the prospects of the agent for in vivo measurements.