Aggregation-induced electrochemiluminescence of zirconium metal-organic framework with strain-promoted azide-alkyne...

In this work, zirconium metal-organic framework (MOF) luminophore named Zr-TCPB with aggregation-induced electrochemiluminescence (AIECL) characteristics was effectively synthesized through the self-assembly of the AIE molecule 1,2,4,5-tetrakis (4-carboxyphenyl) benzene (H₄TCPB) as the organic ligand and the metal Zr as the metal node. The framework architecture of Zr-TCPB limited the restriction of intramolecular motions of H₄TCPB, enhancing its ECL performance. Furthermore, the high porosity and specific surface area of the MOFs increased more electrochemical active sites. Consequently, we built a novel AIECL biosensor using Zr-TCPB as the emitter for the sensitive detection of microRNA incorporating silver nanoparticles (Ag NPs) labled DNA tetrahedrons signal dual-amplification strategy. Upon the initiation of DNA hairpin opening by microRNA at the electrode interface, the concealed click reaction group was unveiled through strand displacement polymerization, which bioconjugated with a multiple Ag NPs-DNA tetrahedral nanostructures by azide-alkyne cycloaddition click reaction. Additionally, Ag NPs were used as coreaction accelerators to catalyze K₂S₂O₈, generating more SO₄^•- and thereby amplifying the ECL signals, achieving signal dual-amplification. The established method achieved accurate quantitative detection of miRNA-21 in the range from 100 aM to 10 nM with a low detection limit of 67.2 aM. More importantly, it exhibited exceptional selectivity and stability, making it a promising approach to monitor miRNA biomarkers, while opening up fresh avenues to bolster the application potential of AIECL MOFs and azide-alkyne cycloaddition click reaction in biosensors.