Quantum dots and duplex-specific nuclease enabled ultrasensitive detection and serotyping of Dengue viruses in one step in a single tube

● Rapid detection and serotyping of Dengue viruses were achieved in one step.● The simple biosensor achieved target recycling and isothermal signal amplification.● The high specificity of DSN endowed this biosensor a good selectivity.● The use of magnetic beads produced an ultralow fluorescence background.

Leveraging on the enzymatic processing of Dengue virus (DV) RNA hybridized quantum dot-capped DNA capture probes (QD–CPs), an ultrasensitive assay for the detection and serotyping of DVs is described in the report. Briefly, DV-specific DNA CPs are first capped by QDs and then conjugated to magnetic beads. In a sample solution, strands of DV RNA form heteroduplexes with the QD–CPs on the magnetic beads. The CPs together with the QDs in the heteroduplexes are subsequently cleaved off the magnetic beads by a duplex-specific nuclease (DSN), releasing the QDs to the solution, freeing the target RNA strands, and availing them for another around of hybridization with the remaining QD–CPs. After removing the magnetic beads along with unreacted (uncleaved) QD–CPs by using a permanent magnet, ultrasensitive fluorescent detection of DV is realized through the cleaved QDs. Serotyping of DV is accomplished by a judicious design of the QD–CPs. The assay combines excellent signal generation by the highly fluorescent QDs and the effortlessness of utilizing magnetic beads in the removal of the unreacted QD–CPs. The highly efficient DSN cleavage in conjunction with its excellent mismatch discrimination ability permits serotyping of DVs in one tube with excellent sensitivity and selectivity.