▎ 摘　　要

A freely switchable DNA monitoring platform based on poly(xanthurenic acid) functionalized FePt/reduced graphene oxide (PXa-FePt/RGO) was developed, where the PXa and FePt/RGO were synchronously synthesized via an effective pulse potentiostatic method. The obtained nanocomposite integrated the advantages of the PXa and FePt/RGO, including rich-conjugated structures, good conductivity, and fine biocompatibility, which not only served as a substrate for DNA immobilization but also reflected the electrochemical transduction originating from DNA immobilization and hybridization without any complicated labeling or outer indicators. The immobilization of probe DNA was successfully conducted via noncovalent assembly due to the pi-pi* interaction between the conjugated nanocomposite and DNA bases. After the hybridization of probe DNA with target DNA, the formation of double-helix structure induced dsDNA to release from the surface of conjugated nanocomposite, accompanied with the self-signal regeneration of nanocomposite ("signal-on"). The developed biosensor exhibited excellent performance for the detection of the sequence-specific DNA from chronic myelogenous leukemia by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) with a detection limit of 2.1 x 10(-16) mol/L.