Curcumin-Based "Enhanced SNAr" Promoted Ultrafast Fluorescent Probe for Thiophenols Detection in Aqueous Solution and in Living Cells

Abstract

We report herein a highly selective and sensitive turn-on fluorescent probe (compound 1) with a fast response time (less than 2 min) for thiophenol detection based on an enhanced SNAr reaction between thiophenols and a sulfonyl-ester moiety covalently attach to curcumin. Reaction of 1 in Hepes-MeOH (1:1, v/v, pH 7.4) in the presence of 4-methylthiophenol (MTP) resulted in a remarkable enhancement of the fluorescence. A linear response in the presence of MTP of the relative fluorescent intensity (F - F0) of 1 at 536 nm in the 0-40 mu M MTP concentration range was found. A limit of detection (LOD) for the detection of MTP of 26 nM, based on the definition by IUPAC (C-DL = 3 Sb/m), was calculated. Probe 1 was applied to monitor and imaging exogenous MTP in live cells and to the detection of MTP in real water samples.