Highly sensitive detection of Hg2+ using covalent linking single-strand DNA to the surface of graphene oxide with co-anchor strand

Physical adsorption techniques used for the detection of Hg2+ have characteristic disadvantages that compromise the Hg2+ sensitivity, and thus present false signals that affect the resulting outcome. Here, in order to avoid the aforementioned drawbacks and improve detection sensitivity, a single-stranded DNA sequence modified with an amino group and FAM (carboxyfluorescein) was immobilized onto the surface of graphene oxide (GO). A co-anchor strand with an amino group was then attached to further develop the sensor, which resulted in an improved efficiency of DNA sequence immobilization onto the GO surface and an improvement in the limit of detection of Hg2+. The detection limit was found to be 2.52 nM in this study.