Highly Efficient Electrochemiluminescence Based on Luminol/MoS2 Quantum Dots@Zeolitic Imidazolate Framework-8 as an Emitter for Ultrasensitive Detection of MicroRNA

Herein, a highly efficient electrochemiluminescence (ECL) emitter, luminol/MoS2 quantum dots@zeolitic imidazolate framework-8 (Lu/MoS2 QDs@ZIF-8), with a positive charge was prepared to construct a novel luminol-H2O2-MoS2 QD ternary ECL system for ultrasensitive detection of microRNA-21 (miRNA-21). The porous Lu/MoS2 QDs@ZIF-8 was beneficial for reducing the accessible distance between various participants in the ternary system wherein co-reaction accelerator MoS2 QDs promoted H2O2 to generate superoxide anion radicals (O2•-), which instantaneously reacted with luminol to produce robust ECL signals. Simultaneously, the positively charged Lu/MoS2 QDs@ZIF-8 facilitated the enrichment of O2•- to further improve the ECL efficiency of luminol. Impressively, compared with the traditional binary luminol-H2O2 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/MoS2 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.