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Updated: Nov 8, 2025
Rapid Nanoprobe Signal Enhancement by In Situ Gold Nanoparticle Synthesis
Published on: March 7, 2018
Highly selective and rapid detection of silver ions by using a "turn on" non-fluorescent cysteine stabilized gold
Jun Wang1, An-Yong Liu1, Bi-Chao Wu1
1Functional Molecules Analysis and Biotransformation Key Laboratory of Universities in Yunnan Province, National Demonstration Center for Experimental Chemistry and Chemical Engineering Education (Yunnan University), School of Chemical Science and Technology, Yunnan University, Kunming 650091, China. lingjian@ynu.edu.cn qecao@ynu.edu.cn.
Abstract:
Cysteine is widely used as a stabilizer for the preparation of fluorescent gold nanoclusters (Au NCs) with different fluorescence properties. Herein, by using cysteine as a stabilizer and controlling the synthesis conditions, a new non-fluorescent cysteine stabilized gold nanocluster (Cys-Au NCs) probe was prepared and a new strategy for "turning on" the fluorescence of the Cys-Au NCs was studied for rapid and selective detection of silver ions. In this strategy, the addition of silver ions to non-fluorescent Cys-Au NCs solution could quickly induce a visible fluorescence "turn on" phenomenon in 30 s. Further studies indicated that this fluorescence "turn on" phenomenon is specific for silver ions and the "turn on" fluorescence intensity has a linear relationship with the amount of silver ions in the range from 3.0 to 30.0 μM. Therefore, the non-fluorescent Cys-Au NCs were applied to the detection of silver ions in environmental water samples and a limit of detection (LOD) of 0.26 μM was obtained. This research sheds light on new applications of Au NCs and proposes a simple, rapid, sensitive, and visual method for the detection of metal ions.
