Organic small-molecule fluorescent probe-based detection for alkali and alkaline earth metal ions in biological systems

Metal ions widely exist in biological systems and participate in many vital biochemical processes. Monitoring and analyzing metal ions in biological systems can help reveal physiological processes and understand disease causes. There are various detection methods for metal ions, among which organic small-molecule fluorescent probes have significant advantages, such as high fluorescence quantum yield, easy modification, good biocompatibility, high sensitivity, and fast real-time detection. This review presents recent studies on fluorescent probes for alkali and alkaline earth metal ions (including Na+, K+, Ca2+, and Mg2+) in biological systems. All the candidates are organized according to their structures, and the sensing mechanisms of fluorescent probes are also highly taken into account. Finally, the challenges, trends and prospects of fluorescent probes in metal ion detection are discussed. We hope that this review can provide guidance for the development of fluorescent molecular probe-based alkali and alkaline earth metal ion detection methods in the future.