Hetero-molecular junction promoted electrochemiluminescence of porphyrin-based hydrogen-bonded organic framework for antibiotic resistance gene assay

Antibiotic resistance genes (ARGs) pose a significant threat to food safety and human health, underscoring the urgent need for their sensitive and convenient detection. Herein, a “switch-on” electrochemiluminescence (ECL) biosensor is fabricated based on the heterogenized porphyrinic hydrogen-bonded organic framework (PFC-45) as the ECL luminophor and ZnO as the co-reactant accelerator for tetracycline resistant gene ( tetA ) assay. The hetero-ligand PFC-45 effectively performs an intrareticular charge transfer and suppresses aggregation-caused quenching, showing 2.5- and 101.5-fold higher ECL intensity in aqueous solution than that of mono-ligand 5,10,15,20-tetra(4-carboxyphenyl) porphine (TCPP) and 5,10,15,20-tetra(4-pyridyl) porphine (TPyP)-based HOF. Combined with Exonuclease III-assisted target recycling amplification, the proposed biosensor achieves a good specificity and sensitivity for tetA detection with a low detection limit of 65.02 fM. This work expands the application of mixed-ligand porphyrin-based HOFs in ECL sensing and establishes a generalizable paradigm for monitoring antibiotic resistance through target-driven nucleic acid signal amplification.