Designing a novel DNA-based electrochemical biosensor to determine of Ba 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 Ba 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 Ba 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 Ba ions in the presence of other metal ions such as Ag, Hg, K and Na and was applied to the analysis of natural samples showing appropriate results.