Synthesis and evaluation of a new fluorescein and rhodamine B-based chemosensor for highly sensitive and selective detection of cysteine over other amino acids and its application in living cell imaging

Abstract

A new fluorescent probe (TRDM-F) based on a molecular chain of open-loop maleic anhydride, rhodamine B and fluorescein was designed, synthesized and evaluated to develop a chemosensor. Photochemical studies show that fluorescence properties of TRDM-F are dominated by fluorescein group in the pH range of 2–10. UV–vis absorption and fluorescence spectroscopic studies further display a high selectivity towards Cys over GSH/Hcy and other amino acids and a high sensitivity towards Cys (0.088–270μM) with 95-fold fluorescence enhancement in a HEPES buffer solution (10mM, pH=7.4) containing 20% MeCN at room temperature. We further demonstrated that the proposed method was satisfactorily applied to the discrimination of Cys in living Hela cells with low cell toxicity.