A new Cu2+-selective fluorescent probe with six-membered spirocyclic hydrazide and its application in cell imaging

• Published in: Dyes and pigments 2019-12, Vol.171, p.107701, Article 107701
• Main Authors: Huang, Kun, Han, Defang, Li, Xianglin, Peng, Mengni, Zeng, Xianshun, Jing, Linhai, Qin, Dabin
• Format: Article
• Language: English
• Subjects: Copper ions; Fluoran; Fluorescence; Six-membered spirocyclic hydrazide
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2019.107701

A new N-heterocyclic fluoran based dye BiF is facilely prepared in high yield by reaction of 5-methoxybenzimidazole and 2-(4-diethylamino-2-hydroxy)benzoylbenzoic acid in concentrated H2SO4, which keeps stable optical signals in water at pH values ranging from 4 to 10 and exhibits good living cell membrane permeability. By modification of the spirolactone in molecule BiF, a fluorescent probe BiF–Cu with specific and sensitive response to Cu2+ has been further developed, which contains a six-membered spirolic hydroxyethylhydrazide moiety that can be selectively triggered by Cu2+ among various metal ions through a specific cascade reaction of Cu2+-promoted spirolactam ring-opening and hydrolysis. A limit of detection for Cu2+ is calculated as 7.12 × 10−8 mol/L. In addition, the utilization of BiF–Cu for bioimaging Cu2+ in L929 cells demonstrates its living cell membrane permeability and makes it promising candidate for monitoring Cu2+ by cell imaging technology. A new N-heterocyclic fluoran BiF has been efficiently prepared by hybridizing benzimidazole and fluoran moieties. Based on this dye, fluorescent probe BiF–Cu with unique six-membered spirocyclic hydrazide has been developed for selective and sensitive detection of Cu2+ and cell imaging. [Display omitted] •A new N-heterocyclic fluoran dye was prepared with stable optical signal over a wide pH range.•A fluorescent probe containing a novel six-membered spirocyclic hydrazide trigger has been developed.•The probe was empolyed for highly selective and sensitive detection of Cu2+ with a detection limit of 71.2 nM.•The probe can be utilized in tracing Cu2+ in living cell.