A coumarin-based fluorescent probe for highly selective detection of hazardous mercury ions in living organisms

In recent years, heavy metal mercury (II) pollutants have caused serious harm to human health and ecosystems. It has become critical to develop simple and highly selective sensing solutions for monitoring mercury (II). In this work, we designed and developed a novel fluorescent probe Coa-SH using the Hg²⁺-induced chemical reaction as a sensing mechanism. The probe Coa-SH showed high selectivity for the detection of Hg²⁺ by desulfurization reactions in solution. The test strips prepared with this probe could be applied to detect mercury ions in aqueous solutions. In addition, the probe Coa-SH provided a tool to detect Hg²⁺ in living systems. In living cells and zebrafish, the probe turned on bright red fluorescent signals in the presence of mercury ions. Importantly, the probe Coa-SH enabled Hg²⁺ detection in plant onion roots. This work provides an effective method for monitoring mercury ions in the environment and in living organisms.