Progress in research of zinc ion fluorescent probes for biological imaging

Zn²⁺, is one of the indispensable microelements in organisms and plays an important role in organisms. Therefore, it is of great significance to monitor effectively the Zn²⁺ concentration in organisms for the diagnosis and treatment of the related diseases. However, the fluorescence probes have many outstanding advantages, such as high selectivity, good sensitivity, high spatial resolution, simple operation and biological imaging conveniently. The biological imaging can directly show the distribution of Zn²⁺ and the difference of Zn²⁺ concentration in organisms. Thus, it can provide reference for disease diagnosis. In this review, Zn²⁺ fluorescent probes which have been reported in recent ten years are systematically reviewed, including naphthol, 1,8-naphthalimide, pyrene, triphenylamine, quinoline, coumarin, fluorescein, rhodamine and other fluorophores. The discussion of each probe concentrates mainly on its biological imaging. It is believed that the paper will provide a novel insight into the development and research of Zn²⁺ fluorescent probes with low detection limit, good water solubility, perfect biological imaging effect and so on.