Zinc–Metal Organic Frameworks: A Coreactant-free\nElectrochemiluminescence Luminophore for Ratiometric Detection of\nmiRNA-133a

Abstract

Developing\na coreactant-free ratiometric electrochemiluminescence\n(ECL) strategy based on a single luminophore to achieve more accurate\nand sensitive microRNA (miRNA) detection is highly desired. Herein,\nutilizing zinc–metal organic frameworks (Zn-MOFs) as the single\nluminophore, a novel dual-potential ratiometric ECL biosensor was\nconstructed for ultrasensitive detection of miRNA-133a. The as-prepared\nZn-MOFs exhibited simultaneous cathode and anode ECL emission. Furthermore,\nthe Zn-MOFs were confirmed to be a multichannel ECL sensing platform\nwith excellent annihilation and coreactant ECL emission. The corresponding\nECL behaviors were investigated in detail. Benefiting from the hybridization\nchain reaction (HCR) amplification technology, <i>N</i>,<i>N</i>-diethylethylenediamine (DEAEA) was modified on hairpin\nDNA, and the gained products loaded with quantities of DEAEA enhanced\nthe anodic ECL intensity of Zn-MOFs. In the presence of miRNA-133a,\nthe ECL intensity ratio of anode to cathode (<i>I</i>_a/<i>I</i>_c) was significantly increased,\nwhich realized the ultrasensitive ratiometric detection of miRNA-133a.\nIn addition, without an exogenous coreactant, the biosensor revealed\nsuperb accuracy and stability. Under optimal conditions, the detection\nlinearity of miRNA-133a was from 50 aM to 50 fM with a low detection\nlimit of 35.8 aM (S/N = 3). This is the first work to use Zn-MOFs\nas a single emitter for reliable ratiometric ECL bioanalysis, which\nprovides a new perspective for fabricating a ratiometric ECL biosensor\nplatform.