Zn2+ detection by MRI using Ln3+-based complexes: The central role of coordination chemistry

This review deals with the rational design of Gd3+-based complexes for Zn2+ detection. It describes the different possible mechanisms underlying Zn2+ detection with such responsive probes. Those probes are composed of three parts: the Gd3+ complex, the Zn2+ binding unit, and a linker. The role and the importance of each part will be described separately through various examples, and it will be shown how it affects the stability, affinity, and efficacy of the probes. Finally, it will be demonstrated how, knowing the mechanism of action of the complex for Zn2+ detection, such probes can be optimized. The aim is to try to establish relationships between the structure and the efficacy of the agents to design rationally more efficient contrast agents in the future. (C) 2018 Elsevier B.V. All rights reserved.