Cu2+ Biological Imaging Probes Based on Different Sensing Mechanisms

In recent years, fluorescent probes have recently attracted attention from researchers. As a vital trace metal element, Cu2+ has an important role in the human body and environment. Therefore, the development and design of Cu2+ small-molecular fluorescent probes has been an active research area. This review focuses on the developments in the area of small-molecular fluorescent probes for Cu2+ in biological applications according to different sensing mechanisms including charge transfer (CT), electron transfer, energy transfer, excited-state intramolecular proton transfer (ESIPT).