Porous FeO@COF-Immobilized gold nanoparticles with excellent catalytic performance for sensitive electrochemical detection of ATP.

In this work, a "signal-off" electrochemical biosensor was established for sensitive detection of adenosine triphosphate (ATP) based on FeO@covalent organic framework-immobilized gold nanoparticles (FeO@COF-Au NPs) porous composite material as a nanocarrier. The proposed FeO@COF-Au NPs could effectively confine Au NPs in the uniform channels of the FeO@COF, which successfully avoided Au NPs aggregation to a certain extent and provided a comparatively independent and stable micro-environment via its hydrophobic porous nanochannels, thereby owning excellent electro-catalytic performance for the reduction of 4-nitrophenol. Moreover, the FeO@COF-Au NPs nanomaterials were served as functional platform for immobilizing DNA substrate (S0), which was used to bind with the conversion product (S1) of the target ATP for subsequent branched hybridization chain reaction (b-HCR) to form dendritic DNA strands to hinder electron transfer between FeO@COF-Au NPs and 4-nitrophenol, finally achieving sensitive detection of ATP with a wide linear range of 5 pM-50 μM and a low detection limit of 1.6 pM. Such strategy provides a multifunctional immobilized platform for the sensitive detection of ATP and a versatile strategy for monitoring other biomolecules.