Electrochemical analysis of microRNAs with hybridization chain reaction-based triple signal amplification

Selective and sensitive detection of trace microRNA is important for early diagnosis of diseases due to its expression level related to diseases. Herein, a triple signal amplification strategy is developed for trace microRNA-21 (miRNA-21) detection by combining with target-triggered cyclic strand displacement reac-tion (TCSDR), hybridization chain reaction (HCR) and enzyme catalytic amplification. Four DNA hairpins (H1, H2, H3, H4) are employed to form an ultralong double-strand DNA (dsDNA) structure, which is ini-tiated by target miRNA-21. As H3 and H4 are labeled with horseradish peroxidase (HRP), numerous HRPs are loaded on the long dsDNA, producing significantly enhanced electrocatalytic signals in the hydrogen peroxide (H2O2) and 3,3 ' ,5,5 '-tetramethylbenzidine (TMB) reaction strategy. Compared with single signal amplification, the triple signal amplification strategy shows higher electrochemical response, wider dy-namic range and lower detection limit for miRNA-21 detection with excellent selectivity, reproducibility and stability. Taking advantage of the triple signal amplification strategy, the proposed electrochemical biosensor can detect miRNA-21 in 10 HeLa cell lysates, suggesting that it is a promising method for fruit-ful assay in clinical diagnosis. (c) 2023 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

Automated summary

Selective and sensitive detection of trace microRNA is achieved through a triple signal amplification strategy combining target-triggered cyclic strand displacement reaction (TCSDR), hybridization chain reaction (HCR), and enzyme catalytic amplification. This strategy shows higher electrochemical response, wider dynamic range, and lower detection limit for miRNA-21, demonstrating excellent selectivity, reproducibility, and stability. The proposed electrochemical biosensor successfully detects miRNA-21 in 10 HeLa cell lysates, suggesting its promising application in clinical diagnosis.