Reaction-based fluorescent probes for Hg2+, Cu2+ and Fe3+/Fe2+

Transition metal ions were inextricably connected with medicine, life sciences, and environmental science. Some metal ions such as mercury ions, copper ions and iron irons in the environment cannot be degraded and easily enriched at organisms via the obvious biomagnification of food chain, causing a great hazard on human health as well as environment. Therefore, the issue how to monitor the changes and content of metal ions in organisms and environment timely and effectively has become an urgent need for detection techniques. The reaction-based fluorescent probes realize the identification and detection of the analytes through the obvious change of the fluorescence after the chemical reaction between the probes and the target analytes, showing a higher sensitivity and selectivity than those of the traditional chelating probes. This review summarizes the research progress of reaction-based fluorescent probes for the detection of Hg2+, Cu2+and Fe3+/Fe2+ in the past ten years. The detection mechanism of these reaction-typed probes is described in detail, and their application in biological system is explained. The defects of these kinds of metal ion probes emerging at this stage are analyzed and discussed, the possible solutions are given. It can be predicted that the trend of development of metal ion probes in the future is to involve more disciplines with the help of analyzing the mechanism and practical application of a series of reaction-based probes. The close combination of chemistry and biology is needed eagerly to develop the higher-level ones with broad application prospects. At the same time, more in-depth research on the mechanism of metal ions and probes must also be guaranteed. Moreover, through studying and summarizing the identification rules of metal ions, and relying on a set of universal detection mechanisms, it is expected to develop accurately the novel specific and high-performance probes based on reactions for Hg2+, Cu2+and Fe3+/Fe2+ detection.