Rational Design of an Ultrasensitive and Highly Selective Chemodosimeter by a Dual Quenching Mechanism for Cysteine Based on a Facile Michael-Transcyclization Cascade Reaction

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• 作者：Xiangmin Li ; Yongjun Zheng ; Hongjuan Tong ; Rui Qian ; Dr. Lin Zhou ; Prof. Dr. Guixia Liu ; Prof. Dr. Yun Tang ; Prof. Dr. Hao Li ; Prof. Dr. Kaiyan Lou and Prof. Dr. Wei Wang
• 刊名：Chemistry - A European Journal
• 出版年：2016
• 出版时间：June 27, 2016
• 年：2016
• 卷：22
• 期：27
• 页码：9247-9256
• 全文大小：2427K
• ISSN：1521-3765

文摘

Differentiation of biologically important thiols, such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) is still a challenging task. Herein, we present a novel fluorescent chemodosimeter capable of selectively detecting Cys over other biothiols including Hcy and GSH and other amino acids by a facile thiol-Michael addition/transcyclization rearrangement cascade click process. The unique transcyclization step is critical for the selectivity as a result of the kinetically favorable formation of a six-membered ring with the Cys Michael adduct. Moreover, the probe adopts a distinctive dual quenching mechanism—photoinduced electron transfer (PET) and photoinduced intramolecular charge transfer (ICT) to deliver a drastic turn-on fluorescence response only at the Cys-selective transcylization step. The judicious selection of strong electron-withdrawing naphthalimide fluorophore with maleimide group enhances the electrophilicity and thus reactivity for the cascade process leading to fast detection and ultrasensitivity with a detection limit of 2.0 nm (S/N=3). The probe has demonstrated its practical utility potential in Cys imaging in live cells.