Multiplexed and amplified electronic sensor for the detection of microRNAs from cancer cells.

The detection of microRNA expression profiles plays an important role in early diagnosis of different cancers. On the basis of the employment of redox labels with distinct potential positions and duplex specific nuclease (DSN)-assisted target recycling signal amplifications, we have developed a multiplexed and convenient electronic sensor for highly sensitive detection of microRNA (miRNA)-141 and miRNA-21. The sensor is constructed by self-assembly of thiol-modified, redox species-labeled hairpin probes on the gold sensing electrode. The hybridizations between the target miRNAs and the surface-immobilized probes lead to the formation of RNA/DNA duplexes, and DSN subsequently cleaves the redox-labeled hairpin probes of the RNA/DNA duplexes to recycle the target miRNAs and to generate significantly amplified current suppression at different potentials for multiplexed detection of miRNA-141 and miRNA-21 down to 4.2 and 3.0 fM, respectively. The sensor is also highly selective toward the target miRNAs and can be employed to monitor miRNAs from human prostate carcinoma (22Rv1) and breast cancer (MCF-7) cell lysates simultaneously. The sensor reported here thus holds great potential for the development of multiplexed, sensitive, selective, and simple sensing platforms for simultaneous detection of a variety of miRNA biomarkers for clinic applications with careful selection of the labels.