Highly Efficient Electrochemiluminescence Based on Luminol/MoS Quantum Dots@Zeolitic Imidazolate Framework-8 as an Emitter for Ultrasensitive Detection of MicroRNA.

Herein, a highly efficient electrochemiluminescence (ECL) emitter, luminol/MoS quantum dots@zeolitic imidazolate framework-8 (Lu/MoS QDs@ZIF-8), with a positive charge was prepared to construct a novel luminol-HO-MoS QD ternary ECL system for ultrasensitive detection of microRNA-21 (miRNA-21). The porous Lu/MoS QDs@ZIF-8 was beneficial for reducing the accessible distance between various participants in the ternary system wherein co-reaction accelerator MoS QDs promoted HO to generate superoxide anion radicals (O), which instantaneously reacted with luminol to produce robust ECL signals. Simultaneously, the positively charged Lu/MoS QDs@ZIF-8 facilitated the enrichment of O to further improve the ECL efficiency of luminol. Impressively, compared with the traditional binary luminol-HO system, the ECL efficiency of this ternary system was increased by 12.7 times. In the aid of a target-cycled and endogenous adenosine triphosphate-driven signal amplification strategy, the biosensor with Lu/MoS QDs@ZIF-8 as an ECL emitter achieved ultrasensitive detection for miRNA-21 with a detection limit of 14.6 aM. This work provides a promising perspective to construct a highly efficient ECL ternary system for biomolecule detection and potential disease diagnosis.