Search

Based on a fluoran skeleton, we herein reported a new fluorescent probe FLACu for Cu2+ by facile modification of the spirolactone of dye 1 with phenylhydrazine. Taking advantage of the spirolactam moiety, FLACu only delivers a specific "off-on" fluorescence signal output towards Cu2+ when treated with various metal ions, which has been well elucidated as the result of spirolactam ring opening and hydrolysis processes induced by copper ion. Meanwhile, the limit of detection (LOD) for FLACu has been estimated to be 35.4 nM and a pH range of 5.0–9.0 is evaluated to be suitable for Cu2+ detection. Significantly, FLACu shows low cell cytotoxicity and can be further ultilzied in the detection of exogenous Cu2+ in the living Hela cells. [ABSTRACT FROM AUTHOR]

A new biscarbazole-fused xanthene hybrid dye MeBCX has been prepared by CH3SO3H-promoted condensation of 4-hydroxycarbazole and o-phthalic anhydride, followed by esterification with methanol, which exhibits good cell membrane permeability. Taking advantage of the spiro-controlled xanthene platform of the dye, a Cu2+-selective fluorescence "off-on" probe BCX-Cu has been successfully prepared with excellent performances in selectivity and sensitivity, and the detection limit is calculated to be 88.7 nM. The sensing mechanism is confirmed to involve a specific cascade reactions of Cu2+-induced spirolactam ring-opening and hydrolysis. In addition, living L929 cell imaging demonstrates the probe has living cell membrane permeability and shows great potential for tracing intracellular Cu2+ through fluorescence imaging technology. [ABSTRACT FROM AUTHOR]