Carbohydrazide-induced low triggering potential electrochemiluminescence from perylene-based metal-organic framework for bioanalysis.

3,4,9,10-perylenetetracarboxylic acid (PTCA), as a typical polycyclic aromatic hydrocarbon (PAH), has become a special electrochemiluminescence (ECL) luminophore by virtue of its high quantum yield and excellent photoelectric properties. However, its aggregation-caused quenching (ACQ) effect and high ECL potentials (usually greater than -1.5 V vs Ag/AgCl) limited its application. In this work, a dual-ligand metal-organic framework (d-MOF) with zinc ion (Zn2+) as the metal node and luminophore PTCA and electroactive agent carbohydrazide (CON4H6) as ligands was developed to address the application limitations of PTCA. The synthesis of PTCA-based MOF reduced the ACQ of PTCA. The introduction of CON4H6 not only increased the porosity and surface area of d-MOF, but also acted as a coreaction accelerator to accelerate the reduction of persulfate ions (S2O82-). As a result, the resulting d-MOF exhibited a strong ECL emission at a low potential of -1.1 V. Impressively, compared with single-ligand MOF (s-MOF) with PTCA alone, the ECL efficiency of d-MOF with PTCA and CON4H6 was enhanced by 14.6 times. The d-MOF coupled toehold-mediated strand displacement (TMSD) reaction and telomerase extension of telomeric DNA strategy to achieve an ultrasensitive detection of antibiotic kanamycin (KAN) with a limit of detection of 0.24 fM. This strategy not only innovatively applied hydrazine compounds as the second ligand to reduce the ECL potential of PTCA-based MOF, but also developed a low ECL triggering potential d-MOF and created a promising platform for KAN assay.