A fluorescent signal "removal" sensor via duplex-specific nuclease-aided cleavage for miRNA detection in flow cytometry.

Considered as the next-generation biomarkers, microRNAs play an important role in the early diagnosis of cancers. Here, we designed a fluorescent signal "removal" sensor for one-step, sensitive and specific detection of multiple microRNAs by flow cytometry (FCM). In this work, single-stranded DNA (ssDNA), working as the interlinkage, immobilized the fluorescent nanosphere (FS) onto the SiO microspheres surface to form the SiO-ssDNA-FS probes. When target miRNAs integrated with SiO-ssDNA-FS probes, the duplex-specific nuclease (DSN) could cleave the ssDNA selectively and release FS with numerous cycles to enhance the fluorescent signal attenuation of SiO-ssDNA-FS, so as to remarkably improve the analysis sensitivity. It achieved a simple, accurate and quantitative microRNA-21 detection for clinical blood samples. Parallel multi-target detection of microRNA-21 and Let-7d was also realized by different color labeled FS. Moreover, our designed sensor was suitable for other targets' detection with the corresponding probes.