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 Fe 3 O 4 to form nanocomposites of Fe 3 O 4 @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 Fe 3 O 4 @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 Fe 3 O 4 @3D-GO exhibits highly selectivity, good repeatability, and stability for detecting Ag + ions. The results of this work demonstrate that Fe 3 O 4 @3D-GO nanocomposites could be used as a promising tool to detect heavy metal ions in water or the environment.