An Ultrasensitive DNA Sensor for Hg2+ Assay Based on Electrodeposited Au/Carbon Nanofibers-chitosan and Reduced Graphene Oxide

An ultrasensitive electrochemical DNA sensor was designed for Hg 2+ assay using cooperative signal amplification effect of electrodeposited Au/carbon nanofibers-chitosan (DpAu/CNFs-CS) and reduced graphene oxide (RGO). CNFs-CS was prepared to modify gold electrode (AuE). Then, Au was electrodeposited on CNFs-CS/AuE to form DpAu/CNFs-CS/AuE for the first signal amplification. With TH as signal probe and ssDNA as recognition component, RGO/ssDNA and RGO/TH interaction were used for the second signal amplification. The prepared sensor had wider linear range of 0.0001–460 nM and lower detection limit of 5.7×10 −5 nM, high selectivity, and performed well in Hg 2+ assay of tap water.