A feasible C-rich DNA electrochemical biosensor based on Fe3O4@3D-GO for sensitive and selective detection of Ag+

It is highly desirable and a popular topic in scientific research to develop a highly sensitive and selective detection and quantitative analysis method of determining trace silver ions (Ag+) in aqueous media since Ag+ ions are recognized as one of the most hazardous metal pollutants. Three-dimensional graphene oxide (3D-GO) was decorated with Fe3O4 to form nanocomposites of Fe3O4@3D-GO, which were further used as electrode materials in an electrochemical DNA sensor for detecting Ag+. Because of the chemical functionality and porous structure of the developed nanocomposites, single-stranded and cytosine-rich oligonucleotides could be anchored onto their surfaces or interior, followed by selective detection of Ag+ through formation of C-Ag+-C complex forms. The results of electrochemical measurement showed that the Fe3O4@3D-GO nanocomposites exhibits high sensitivity for detecting Ag+ with a detection limit of 2.0 pM within the range of 0.01 - 100 nM Ag+ (S/N = 3). The developed electrochemical biosensor based on Fe3O4@3D-GO exhibits highly selectivity, good repeatability, and stability for detecting Ag+ ions. The results of this work demonstrate that Fe3O4@3D-GO nanocomposites could be used as a promising tool to detect heavy metal ions in water or the environment. (C) 2015 Elsevier B.V. All rights reserved.