Dual microRNAs-Fueled DNA Nanogears: A Case of Regenerated Strategy for Multiple Electrochemiluminescence Detection of microRNAs with Single Luminophore

The determination of multiple biomarkers from cancer cells features a considerable step toward early diagnosis of cancers. However, realizing different biomarkers detection with single electrochemiluminescence (ECL) luminophore and regenerating the sensing platform remain a compelling goal. Herein, dual miRNAs-fueled DNA nanogears were designed for an enzyme-free ECL biosensor construction to perform the multiple sensitive detection of the microRNA (miRNA) biomarkers with single luminophore. The nanogears were assembled on CdS quantum dots (QDs) modified sensing surface. Using miRNA-21 as motive power, Au nanoparticles (AuNPs)-labeled nanogears B could be activated to roll against nanogear A, increasing the distance between AuNPs and CdS QDs. Thus, the significant ECL enhancement of CdS QDs was obtained owing to the ECL energy transfer between AuNPs and CdS QDs, simultaneously realizing the detection of miRNA-21. After the incubation of miRNA-155, nanogear B revolved against nanogear A continuously and realized the close-range of AuNPs and CdS QDs, resulting in the quenching of ECL intensity due to the Förster energy transfer and realizing the analysis of miRNA-155. The successive locomotion of the nanogears led to a significant ECL increasing for analysis of miRNA-21 down to 0.16 fM and a remarkable ECL suppression for determination of miRNA-155 down to 0.33 fM. Impressively, the proposed biosensor was able to be regenerated along with the gears roll against each other. In general, this enzyme-free strategy initiates a new thought to realize the multiple ECL detection with single luminophore, paving the way for applications of nanomachines in biosensing and clinical diagnosis.