Facile preparation of naphthol AS-based fluorescent probe for highly selective detection of cysteine in aqueous solution and its imaging application in living cells

Abstract

A simple and new fluorescent probe (1) for selective detection of cysteine (Cys) in aqueous solution was facilely synthesized. It was developed based on the masking the phenolic OH group in naphthol AS by a methacrylate group, where the methacrylate group acts as an electron acceptor to quench fluorescence of naphthol AS as well as a reactive site for Cys. The conjugate addition/cyclization reaction of Cys toward methacrylate moiety in the probe 1 led to a cleavage of the methacrylate group and release of free naphthol AS, thereby induced a significant enhancement of fluorescence. The present fluorescent probe exhibited high selectivity toward Cys over homocysteine (Hcy) and glutathione (GSH) and worked well in a physiological aqueous medium, allowing a successful application in living cells imaging.