pH‐Driven Actuation of Unmodified DNA Origami Rectangles

Abstract

ABSTRACT DNA origami is a versatile method for constructing molecular machinery, yet many designs rely on responsive motifs or added components to achieve dynamic behavior. Here, we show that unmodified DNA origami rectangles—one of the most widely used DNA origami structures—exhibit a reversible transition between planar and tubular states upon pH modulation. We propose that this transformation occurs due to the cooperative mechanical coupling of crossover junctions in overwound DNA: no DNA modification, special sequences, or extra motifs are needed. The curling/uncurling response extends to connected rectangles: dimers and nanoribbons curl reversibly below pH 7 to form nanotube architectures. This unexpected conformational flexibility of monolayer DNA with pH provides a simple framework for engineering responsive nanostructures that can be transformed without chemical modification or specific sequence motifs.