A tandem DNA nanomachines-supported electrochemiluminescence assay for attomolar detection of miRNA at ambient-temperature

Differential expression profiles of miRNAs are linked with a variety of diseases and could serve as biomarkers for routine clinical diagnosis and treatment response. However, the simple, reliable, and highly sensitive quantification remains one of the major challenges in miRNA application. Here we report an ambient-temperature tandem DNA nanomachines-supported electrochemiluminescence (ECL) assay that leverages a tandem two DNA nanomachines (three-dimensional (3D) DNA walker, DNA rolling machine) and the electrochemiluminescence technique for the rapid, ultrasensitive and specific detection of miRNA-155. We demonstrate that the proposed assay is able to detect target miRNA-155 down to 0.33 aM in about 70 min. Notably, the whole procedure can be operated at room temperature since it is protein enzyme-free. It also demonstrates desirable selectivity, excellent stability, and quantitative ability for human serum miRNA-155 detection. In summary, this assay could be used as an ultrasensitive, simple, and reliable diagnostic test for miRNA.