An electrochemiluminescent aptasensor based on porphyrin-based covalent organic framework for the sensitive detection of kanamycin.

Herein, an electrochemiluminescent (ECL) aptasensor based on porphyrin-based covalent organic framework (TP-COF) was constructed for the ultrasensitive detection of kanamycin (KANA). The ordered porous channels and porphyrin-centered π-conjugated framework of TP-COF optimize the interfacial microenvironment and accelerate electron transfer, facilitate the generation of luminol-derived active intermediates, and remarkably boost ECL emission. The modification of Au NPs on the surface of COF could improve interfacial conductivity and provide anchoring sites for thiolated DNA immobilization. Platinum-copper nanocages (PtCu) were employed as an ECL quencher and assembled onto the electrode via DNA hybridization to generate the initial "light-off" state. Upon target recognition, the aptamer was preferentially bind with KANA to dissociate PtCu from the electrode surface and restore the ECL signal. Under the optimal condition, the sensor exhibited linear response toward KANA over the range of 1.0 × 10-15 to 1.0 × 10-13 mol L-1, with a detection limit of 8.9 × 10-16 mol L-1. In addition, the satisfactory repeatability, stability, and selectivity were achieved. This strategy integrates COF-mediated interfacial regulation, noble-metal-assisted signal amplification, and aptamer-triggered dequenching, offering a promising platform for the ultrasensitive analysis of antibiotic residues.