Design and Synthesis of a Novel Magnetic Resonance Imaging Contrast Agent for Selective Sensing of Zinc Ion Original Research Article

A series of new diethylenetriaminepentaacetic acid (DTPA)-bisamide chelators has been prepared and characterized for application as zinc sensors. We have designed and synthesized (GdLa)2−, which contains a DTPA-bisamide moiety. The R1 relaxivity of (GdLa)2− solution decreased monotonically on the addition of Zn2+. Moreover, (GdLa)2− showed high selectivity for Zn2+ against Ca2+ and Mg2+. We also measured the UV-visible spectra and the coldspray ionization (CSI) MS spectra and concluded that the 1-to-1 Zn2+ complex of (GdLa)2− is stable at higher concentrations of Zn2+. These complexes should provide the basis for creating a superior Zn2+-sensitive MRI contrast agent and are excellent candidates for incorporation into sensors designed for selective detection of Zn2+ in biological applications.