Construction and application of electrochemical aptamer sensor for high-sensitivity detection of lead ions by taking methylene blue as indicator

The invention discloses a construction and application method of an electrochemical aptamer sensor for high-sensitivity detection of lead ions (Pb) by using methylene blue (MB) as an indicator. Acarbon ionic liquid electrode is used as a substrate electrode, platinum-loaded carbon nanofiber and nanogold are used as sensitizing materials for sensing interface modification, a capture probe is self-assembled on the surface of the electrode by using a gold-sulfur bond, non-specific adsorption is eliminated by using thioglycollic acid, a stable double-stranded DNA structure is formed by further combining an aptamer probe, and an electrochemical aptamer sensor for detecting Pb is constructed by using MB as a hybridization indicator. According to the working principle, Pb can inducean aptamer probe rich in G basic groups to form a G-quadruplex conformation, so that a duplex structure is destroyed to form a more stable G-quadruplex structure, the MB embedded into the double chains is released from the sur