Nanoconfinement Effect and Cu _<i>x</i> O Nanorod Electrocatalysts Enhance COF@Lu Electrochemiluminescence for Biosensing

The insufficient molecular transport and reaction kinetics of the intermediate free radicals and coreactants are the main reasons for the low electroluminescence (ECL) efficiency of luminol. To solve this question, this work combined the nanoconfinement effect of a unique COF@Luminol with the efficient electrocatalyst regulation of Cu_<i>x</i>O nanorods (Cu_<i>x</i>O NRs), significantly improving the ECL efficiency of luminol. Herein, luminol was embedded in the porous material covalent organic framework (COF_DVA-TAPT) to produce an ECL emitter, COF_DVA-TAPT@Luminol (COF@Lu), for the first time. Based on the nanoconfinement effect, COF@Lu could produce a superior positive potential ECL signal with an ECL efficiency 60.14 times that of luminol alone. To further enhance the ECL intensity of COF@Lu, this work introduced an electrocatalyst, Cu_<i>x</i>O NRs, using tetrahedral DNA nanostructures (TDNs). Cu_<i>x</i>O NRs could catalyze the electrochemical reduction of the coreactant H₂O₂, generating a large amount of reactive oxygen species (ROS), thereby further amplifying the ECL intensity of COF@Lu by 6.6 times. As a proof-of-concept application, an ingenious ECL biosensor combined with smartphone colorimetric (CL) imaging for the dual-mode detection of deoxynivalenol (DON) was prepared. This dual-mode biosensing and imaging platform exhibited superior detection performance without any DNA amplification strategies. Overall, this work significantly amplified the ECL efficiency of luminol based on the nanoconfinement effect and electrocatalyst regulation, improving the sensitivity of target detection and providing an interesting strategy for visual detection.