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Updated: Jan 30, 2026

Design and Development of Aptamer–Gold Nanoparticle Based Colorimetric Assays for In-the-field Applications
Published on: June 23, 2016
A single gold nanoprobe for colorimetric detection of silver(i) ions with dark-field microscopy
Yi Fen Xie1, Yun Ying Cheng, Meng Li Liu
1Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University), Ministry of Education, College of Pharmaceutical Science, Southwest University, Chongqing 400715, China. chengzhi@swu.edu.cn.
Abstract:
Highly sensitive colorimetric detection of silver(i) ions (Ag+) at the single-particle level was developed based on the color of a gold nanoparticle (AuNP) assembly captured by dark-field microscopy (DFM) imaging. Formation of C-Ag+-C bonding between cytosines was utilized to induce interparticle coupling of AuNPs modified with single-strand DNA, resulting in a color change as the signal transduction to quantify Ag+ under DFM imaging. This method allowed visual quantitation of Ag+ in the range of 0.05 nM-250.00 nM and a detection limit of 28.8 pM was achieved. Furthermore, we demonstrated its applicability for the colorimetric detection of Ag+ in a small quantity of real samples, showing the good potential of this developed method for environmental monitoring and drug quality control.
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