Wooli Bae1,2,†, Kipom Kim1,2,*, Duyoung Min1,2, Je-Kyung Ryu1,2, Changbong Hyeon3 & Tae-Young Yoon1,2*
1 National Creative Research Initiative Center for Single-Molecule Systems Biology, KAIST, Daejeon 305-701, South Korea. 2 Department of Physics, KAIST, Daejeon 305-701, South Korea. 3 Korea Institute for Advanced Study, Seoul 130-722, South Korea. † Present address: Department of Physics and Center for Nanoscience (CeNS), Ludwig-Maximilians-Universitat, Geschwister-Scholl-Platz 1, 80539 Munchen, Germany.
*Correspondence to: Tae-Young Yoon or Kipom Kim
Despite the recent development in the design of DNA origami, its folding yet relies on thermal or chemical annealing methods. We here demonstrate mechanical folding of the DNA origami structure via a pathway that has not been accessible to thermal annealing. Using magnetic tweezers, we stretch a single scaffold DNA with mechanical tension to remove its secondary structures, followed by base pairing of the stretched DNA with staple strands. When the force is subsequently quenched, folding of the DNA nanostructure is completed through displacement between the bound staple strands. Each process in the mechanical folding is well defined and free from kinetic traps, enabling us to complete folding within 10 min. We also demonstrate parallel folding of DNA nanostructures through multiplexed manipulation of the scaffold DNAs. Our results suggest a path towards programmability of the folding pathway of DNA nanostructures.