Target-triggered assembly of functional G-quadruplex DNAzyme nanowires for sensitive detection of miRNA in lung tissues

Abstract

MicroRNAs (miRNAs) are important biomarkers for multiple diseases including cancers, neurodegenerative diseases, and cardiovascular diseases. Accurate detection of miRNAs is imperative for early diagnosis and biomedical research. Herein, we demonstrate target-triggered assembly of G-quadruplex DNAzyme nanowires for sensitive detection of miRNAs in lung tissues by integrating primer generation-mediated rolling circle amplification (PG-RCA) with primer exchange reaction (PER). Target miRNA hybridizes with the circular template to initiate PG-RCA, producing numerous primers. The obtained primers then react with the catalytic hairpin DNA template to trigger PER, producing the polymer G-quadruplex DNAzyme nanowires. Eventually, thioflavin T (ThT) as a fluorescence indicator selectively interacts with the G-quadruplex DNAzyme to generate an amplified signal. This assay is capable of detecting miRNA over a large dynamic range (up to 6 orders of magnitude) and it exhibits high sensitivity with a limit of detection (LOD) of 61.34 aM. Moreover, this assay displays excellent specificity and it can distinguish even a single-base mutation in miR-486–5p. Furthermore, this method can quantify the miR-486–5p concentration in different types of cells, and it enables the identification of differentially expressed miR-486–5p in lung tissues of normal persons and nonsmall-cell lung carcinoma (NSCLC) patients, holding promising applications in biomedical analysis and cancer prognosis.