Designing a novel DNA-based electrochemical biosensor to determine of Ba2+ ions both selectively and sensitively

This work describes a novel electrochemical biosensor based on G-quadruplex (G4) DNA for the sensitive and selective detection of Ba2+ ions using a Carbon Paste Electrode modified with Ag nanoparticles incorporated in reduced Graphene Oxide via a simple wet chemical method (Ag-rGO/CPE), in the presence of carmoisine (CA) as a new electrochemical indicator. The peak current of CA increased with increasing Ba2+ ions concentration and the DNA-based sensor showed linear ranges of 0.06–0.80 nM and 1.0–80 nM and a Limit of Detection (LOD) of 0.045 nM. The proposed biosensor showed a good selectivity toward Ba2+ ions in the presence of other metal ions such as Ag+, Hg2+, K+ and Na+ and was applied to the analysis of natural samples showing appropriate results. [Display omitted] •Designing a novel DNA-based electrochemical biosensor to determine of Ba2+ ions.•The Ag nanoparticles incorporated in rGO was prepared with wet chemical method.•Carmoisine was used as a new electrochemical indicator in this DNA-based biosensor.•The proposed biosensor showed a wide LDR, LOD, good stability and reproducibility.