MicroRNAs are short endogenous RNA strands that finely tune gene expression. Countless articles have reported a link between the dysregulation of microRNA expressions and diseases including cancer or neurodegenerative diseases, among others. These disease signatures often involve more than one microRNA. Therefore, multiplex techniques for the sensitive and accurate quantification of microRNAs are needed. In this article, we solve an everlasting problem of chemical reaction crosstalks observed in nucleic acid-based technologies. We rationally designed DNA/enzyme amplification circuits that inhibit each other, preventing from chemical interferences. We demonstrated that this strategy enables to directly quantify multiple microRNAs in a droplet digital format (where each droplet contains 0, 1 or a few of either microRNAs). Up to three microRNAs have been detected simultaneously, using orthogonal DNA circuits. Next step: scale-up this strategy. Stay tuned !

Rondelez, Gines, ACS Sensors, 2020 (open access, ACS Editor’s choice)