One-Step Monitoring of Multiple Enterovirus 71 Infection-Related MicroRNAs Using Core–Satellite Structure of Magnetic Nanobeads and Multicolor Quantum Dots

The accurate and rapid monitoring of the expression levels of enterovirus 71 (EV71)-related microRNAs (miRNAs) can contribute to diagnosis of hand, foot, and mouth disease (HFMD) at the early stage. However, there is currently a lack of convenient methods for simultaneous monitoring of multiplex miRNAs in one step. Herein a one-step method for the simultaneous monitoring of multiple EV71 infection-related miRNAs is developed based on core-satellite structure assembled with magnetic nanobeads and quantum dots (MNs-ssDNA-QDs). In the presence of target miRNAs, duplex-specific nuclease (DSN)-assisted target recycling can be triggered, resulting in the release of QDs and recycling of target miRNAs. Then the simultaneous quantification can be easily realized by recording the corresponding amplified fluorescence signal of QDs in the suspension. With this method, simultaneous detection of hsa-miRNA-296-5p and hsa-miRNA-16-5p, potential biomarkers of EV71 infection, can be easily achieved with femtomolar sensitivity and single-base mismatch specificity. Moreover, the method is successfully used for monitoring of the expression level of miRNAs in EV71-infected cells at different time points, demonstrating the potential for diagnostic applications. With the merits of one-step operation and single-nucleotide mismatch discrimination, this work opens a new avenue for multiplex miRNAs detection. As different nucleotide sequences and multicolor QDs can be employed, this work is expected to offer great potential for the development of high throughput diagnosis.