Metal-based environment-sensitive MRI contrast agents

Interactions of paramagnetic metal complexes with their biological environment can modulate magnetic resonance imaging (MRI) contrast–enhancing properties in different ways, and this has been widely exploited to create responsive probes that provide biochemical information. We survey progress two rapidly growing areas: the MRI detection biologically important ions, such as calcium, zinc, copper, use transition smart agents. In both fields, new technologies, which take advantage other nuclei (19F) and/or contact shift effects, emerge beyond classical, relaxation-based applications. Most importantly, vivo is gaining ground, promise molecular becoming reality, at least for preclinical research.