%0 Journal Article
%T Exonuclease III-propelled DNAzyme walker: an electrochemical strategy for microRNA diagnostics.
%A Li D
%A Huang Q
%A Wang K
%J Mikrochim Acta
%V 191
%N 4
%D 2024 03 4
%M 38436735
%F 6.408
%R 10.1007/s00604-024-06208-4
%X MicroRNA detection is crucial for early infectious disease diagnosis and rapid cancer screening. However, conventional techniques like reverse transcription-quantitative polymerase chain reaction, requiring specialized training and intricate procedures, are less suitable for point-of-care analyses. To address this, we've developed a straightforward amplifier based on an exonuclease III (exo III)-propelled DNAzyme walker for sensitive and selective microRNA detection. This amplifier employs a specially designed hairpin probe with two exposed segments for strand recognition. Once the target microRNA is identified by the hairpin's extended single-strand DNA, exo III initiates its digestion, allowing microRNA regeneration and subsequent hairpin probe digestion cycles. This cyclical process produces a significant amount of DNAzyme, leading to a marked reduction in electrochemical signals. The biosensor exhibits a detection range from 10 fM to 100 pM and achieves a detection limit of 5 fM (3σ criterion). Importantly, by integrating an "And logic gate," our system gains the capacity for simultaneous diagnosis of multiple microRNAs, enhancing its applicability in RNA-based disease diagnostics.