A simple and readily available fluorescent turn-on probe for cysteine detection and bioimaging in living cells

A new simple and readily available fluorescent probe for cysteine (Cys) was reported. This probe is based on an excited-state intramolecular proton transfer (ESIPT) dye and uses two acrylate moieties as the Cys reaction sites to promote signal changes. Importantly, this probe shows rapid fluorescent turn-on signal changes for Cys with high selectivity and sensitivity over various analytes including the similar structured homocysteine (Hcy) and glutathione (GSH) in aqueous solution under mild conditions. The detection limit of this probe for Cys was found to be as low as 0.80 mu M, which is far below the normal content of Cys (30-200 mu M) in cells. This probe was also successfully applied for bioimaging of intracellular Cys in living cells with low cytotoxicity. Besides, a paper test strip system was developed with this probe for a convenient detection of Cys. (C) 2016 Elsevier Ltd. All rights reserved.