A fluorescent probe based on a phenylalanine derivative is capable of sequential detection of Zn²⁺ and Cys/His

A facile and dual fluorescent chemosensor (named 7-IDF) based on a phenylalanine derivative with an indole group was designed and synthesized. 7-IDF can selectively and sensitively detect Zn²⁺ via obvious fluorescence enhancement in an aqueous solution. Remarkably, the 7-IDF-Zn complex with blue luminescence has higher selectivity toward cysteine (Cys) and histidine (His) than for other amino acids. Intriguingly, 7-IDF can also be used as an excellent probe to detect Zn²⁺ in real water samples. Moreover, 7-IDF and 7-IDF-Zn possess excellent biocompatibility and cell permeability, and 7-IDF can consecutively detect Zn²⁺ and Cys/His in Hela cells through fluorescence imaging experiments. This study suggests that the phenylalanine-based chemosensor possesses great potential applications for the sequential detection of Zn²⁺ and Cys/His in biosystems.