A Self-Assembled Nano-Robot for Detection of RNA Molecules

We designed and synthesized self-assembled DNA robots that sense RNA targets and produce fluorescent output signals. We developed a software called “MENDEL” that automated the construction of complex DNA-nanostructures and constructed an in-tube prototype of the robots that successfully reacted to the specific RNA targets and responded by providing a detectable fluorescent signal and an upregulated activity of a reporter gene. Like chromatin assemblies, the structure of the robots self-assembled around the gene’s regulatory elements and concealed them from transcription factors. The existence of the RNA markers activated the release of the robot’s hidden regions and resulted in the expression of the RNA reporters. Experiments demonstrated that the activation of the robot is specific and tunable.Moreover, the high efficiency of the robot in the amplification of the RNA reporter resulted in turbidity of the solution in the reaction tube that could be detected with naked eyes or by a benchtop UV transilluminator. The reported robot is a safe alternative to other viral and bacterial expression systems because its payload is only accessible when the target RNA molecule exists, and therefore it limits off-target interactions. The reported technology could dramatically improve current practices in portable diagnostics systems that will significantly extend national and global access to early and on-site detection of infectious diseases such as COVID-19