Gines G, Menezes R, Nara K, Kirstetter AS, Taly V, Rondelez Y. Isothermal digital detection of microRNAs using background-free molecular circuit.
Sci Adv 2020;
6:eaay5952. [PMID:
32010788 PMCID:
PMC6976291 DOI:
10.1126/sciadv.aay5952]
[Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 11/20/2019] [Indexed: 05/04/2023]
Abstract
MicroRNAs, a class of transcripts involved in the regulation of gene expression, are emerging as promising disease-specific biomarkers accessible from tissues or bodily fluids. However, their accurate quantification from biological samples remains challenging. We report a sensitive and quantitative microRNA detection method using an isothermal amplification chemistry adapted to a droplet digital readout. Building on molecular programming concepts, we design a DNA circuit that converts, thresholds, amplifies, and reports the presence of a specific microRNA, down to the femtomolar concentration. Using a leak absorption mechanism, we were able to suppress nonspecific amplification, classically encountered in other exponential amplification reactions. As a result, we demonstrate that this isothermal amplification scheme is adapted to digital counting of microRNAs: By partitioning the reaction mixture into water-in-oil droplets, resulting in single microRNA encapsulation and amplification, the method provides absolute target quantification. The modularity of our approach enables to repurpose the assay for various microRNA sequences.
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