KCS

We have developed a sensitive aptasensor for the detection of Pb²⁺ ions based on G-quadruplex DNA and an electrochemically reduced graphene oxide (ERGO). Here, ERGO was coated on a glassy carbon electrode (GCE) surface by reduction of graphene oxide using cyclic voltammetry. After that, a methylene blue (MB)-tagged, guanine rich DNA aptamer (Apt) was attached on ERGO surface via π- π interaction. In the presence of Pb²⁺, Apt forms G-quadruplex, leading to the detachment of Apt from the surface of ERGO/GCE. So the conformational change caused by Pb²⁺ produces the change in electrochemical signal. Electrochemical measurements showed highly sensitive detection of Pb²⁺ ions with a liner range from 10^-15~10^-9 M and a detection limit of 0.51 fM. The sensor also has high selectivity of Pb²⁺ ions, high stability, reproducibility, and regeneration.