A new water-soluble coumarin-based fluorescent probe for the detection of Fe3+ and its application in living cells and zebrafish

The pollution caused by heavy metals poses a significant threat to both the natural environment and human health. Therefore, developing straightforward and efficient analytical methods for detecting heavy metal ions is crucial. Given that Fe3+ plays an essential role in biological systems, researchers have worked hard to develop tests that specifically identify Fe3+ in clinical, pharmacological, and environmental settings. Seven novel coumarin amino acid-based Fe3+ fluorescent probes were designed and synthesized in this paper, and their structures were confirmed by 1H/13C NMR and high-resolution mass spectrometry. Spectroscopic tests demonstrated that three compounds (TAC-4, TAC-5, and TAC-7) identified Fe3+ specifically and in particular were able to distinguish between Fe3+ and Fe2+. For example, the fluorescent probe TAC-5 is characterized by its strong selectivity and sensitivity to Fe3+, as evidenced by a large change in fluorescence intensity, a rapid response time (30 seconds), a low detection limit (1.1 μM), and good solubility in water (up to 50%). Furthermore, TAC-5 was successfully used to detect changes in Fe3+ in zebrafish and HeLa Cells and to recognize Fe3+ in the presence of a chelating agent (EDTA). These results are expected to improve the development of new sensitive and selective fluorescence sensors for Fe3+.