Key Laboratory of Analytical Chemistry for Biology and Medicine, Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, PR China.
Institute of Scientific Research and Development, Wuhan University, Wuhan 430072, PR China.
Talanta. 2018 Mar 1;179:742-752. doi: 10.1016/j.talanta.2017.11.057. Epub 2017 Nov 28.
A new label-free fluorescent turn-on-off mode for the sensitive detection of cysteine(Cys) and the identification of Cys over glutathione (GSH) was firstly proposed, mainly on the basis of two different combination ways between Ag ions and GSH-capped gold nanoclusters, or to say, two different contribution ways to the fluorescence enhancement, Ag ions combining with Au core structure and coordinating with carboxylate groups on the surface of gold nanoclusters, respectively (turn-on mode). The Au core-binding Ag ions could merely be captured by Cys for its relatively smaller steric hindrance than that of GSH, resulting in the identification of Cys over GSH. The carboxylate-binding Ag ions could be removed both by Cys and GSH, which, hence, could be used for the qualification of Cys and GSH (turn-off mode). Good selectivity and sensitivity for Cys over other amino acids were achieved. This new turn-on-off sensing strategy for Cys also had obvious advantages of simplicity, rapidity, ease of operation and a low cost. Under the optimized conditions, the linear range was 0.00-2.71μM with the limit of detection of 16.54nM for Cys and 15.59nM for GSH. The probe also had a good application in Cys containing health products.
一种新的无标记荧光开启-关闭模式被首次提出，用于灵敏检测半胱氨酸（Cys）并识别半胱氨酸（Cys）与谷胱甘肽（GSH），主要基于 Ag 离子与 GSH 保护的金纳米簇之间的两种不同结合方式，或者换句话说，两种不同的荧光增强贡献方式，Ag 离子分别与 Au 核结构结合和与金纳米簇表面的羧酸盐基团配位（开启模式）。由于 Cys 的空间位阻相对较小，Au 核结合的 Ag 离子只能被 Cys 捕获，从而实现了对 Cys 的识别。羧酸盐结合的 Ag 离子可以被 Cys 和 GSH 同时去除，因此可以用于定性检测 Cys 和 GSH（关闭模式）。该方法对半胱氨酸具有良好的选择性和灵敏度，优于其他氨基酸。这种新的 Cys 开启-关闭传感策略具有简单、快速、易于操作和低成本的明显优势。在优化条件下，该探针检测 Cys 的线性范围为 0.00-2.71μM，检测限为 16.54nM；检测 GSH 的线性范围为 0.00-2.71μM，检测限为 15.59nM。该探针在含半胱氨酸保健品中的应用也具有良好的效果。
