A dual-amplified electrochemical detection of mRNA based on duplex-specific nuclease and bio-bar-code conjugates

• On the basis of strong preference for cleaving double-stranded DNA or DNA in DNA:RNA heteroduplexes of duplex-specific nuclease (DSN), a dual-amplified electrochemical detection of mRNA was developed.
• To the best of our knowledge, our work is the first reported attempt of coupling DSN based cyclic enhancement with bio-bar-code conjugates, through which the sensitivity was highly improved.
• The method was successfully used in the detection of mRNA.

On the basis of strong preference for cleaving double-stranded DNA or DNA in DNA:RNA heteroduplexes of duplex-specific nuclease (DSN), a dual-amplified electrochemical detection of mRNA was developed in this article, by coupling the enhancement of DSN and bio-bar-code conjugates. Capture probe was linked with magnetic nanoparticles (MNPs) at its 5′ end and bio-bar-code at its 3′ end. In the presence of target surviving mRNA, all hybridized S1 strands were cleaved off the biosensor by the DSN, and the bio-bar-code probe with CdS nanoparticles (CdS NPs) was released into the solution. The metal sulfide nanoparticles were measured by anodic stripping voltammetry (ASV) subsequently. This assay exhibited high sensitivity and selectivity with a detection limit of 0.48 fM. In addition, we proved that this simple and cost-effective strategy is capable of detecting the target in complicated biological samples and holds great potential application in biomedical research and clinical diagnostics.