A Double-Shell Hollow Hf-MOF-Driven Electrochemiluminescence Strategy for the Detection of miRNA-7.

Metal-organic frameworks (MOFs) have emerged as a promising class of luminescence emitters due to their highly tunable structures and intrinsic luminescent characteristics. In this study, a double-shell hollow Hf-MOF (DSH Hf-MOF) was prepared via a dual-template assembly. The DSH Hf-MOF with highly accessible mesoporous/microporous channels, thick walls, and high crystallinity displayed an excellent luminescence property. On the one hand, the double-shell ordered architecture induced significant spatial confinement effects, effectively retarding reactant diffusion and dilution. On the other hand, the double-shell architecture functioned as a parallel circuit, with each shell acting as an independent resistor. The overall resistance was reduced, which significantly improved the efficiency of electron transport. Furthermore, an Ag nanowires@Cu2-xSe Schottky junction array was prepared to provide a uniform and stable electromagnetic field enhancement. Benefiting from the surface plasmonic coupling effect, the luminescence intensity of DSH Hf-MOF was enhanced 7.05 times. The DSH Hf-MOF-driven electrochemiluminescence (ECL) sensor was used for the detection of miRNA-7 with a range from 0.5 fM to 1 nM and a low detection limit of 0.15 fM. More importantly, this biosensor can effectively distinguish between glioma tumor tissues and adjacent paracancerous tissues, demonstrating clear application value in clinical pathological differentiation.