Variable gain DNA nanostructure charge amplifiers for biosensing.

Electronic measurements of engineered nanostructures comprised solely of DNA (DNA origami) enable new signal conditioning modalities for use in biosensing. DNA origami, designed to take on arbitrary shapes and allow programmable motion triggered by conjugated biomolecules, have sufficient mass and charge to generate a large electrochemical signal. Here, we demonstrate the ability to electrostatically control the DNA origami conformation, and thereby the resulting signal amplification, when the structure binds a nucleic acid analyte. Critically, unlike previous studies that employ DNA origami to amplify an electrical signal, we show that the conformation changes under an applied field are reversible. This applied field also simultaneously accelerates structural transitions above the rate determined by thermal motion. We tuned this property of the structures to achieve a response that was ≈2 × 10