Sensing Picomolar Concentrations of RNA Using Switchable Plasmonic Chirality

Angew Chem Int Ed Engl. 2018 Oct 8;57(41):13495-13498. doi: 10.1002/anie.201807029. Epub 2018 Sep 19.


Detecting small sequences of RNA in biological samples such as microRNA or viral RNA demands highly sensitive and specific methods. Here, a reconfigurable DNA origami template has been used where a chiral arrangement of gold nanorods on the structure can lead to the generation of strong circular dichroism (CD). Switching of the cross-like DNA structure is achieved by the addition of nucleic acid sequences, which arrests the structure in one of the possible chiral states by specific molecular recognition. A specific sequence can thus be detected through the resulting changes in the plasmonic CD spectrum. We show the sensitive and selective detection of a target RNA sequence from the hepatitis C virus genome. The RNA binds to a complementary sequence that is part of the lock mechanism, which leads to the formation of a defined state of the plasmonic system with a distinct optical response. With this approach, we were able to detect this specific RNA sequence at concentrations as low as 100 pm.

Keywords: DNA origami; RNA; chirality; plasmonics; sensing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Circular Dichroism
  • DNA / chemistry
  • Hepacivirus / genetics
  • Limit of Detection
  • Microscopy, Electron, Transmission
  • Nucleic Acid Conformation
  • RNA, Viral / analysis*
  • Stereoisomerism


  • RNA, Viral
  • DNA