Fig. 4: In situ visualization of the isothermal folding reveals the multiple folding pathways of a process under thermodynamic control.

a, Cholesterol-modified Λ-shaped origamis were initially adsorbed on a supported lipid bilayer and carried an unfolded M13 fragment to be folded into a third sharp triangle side. The image is a snapshot obtained after 237 min of real-time AFM observation at 25 °C in TANa buffer ([NaCl] = 100 mM) supplemented with 1 mM EDTA, where t = 0 corresponds to the addition of staples programming the folding of the M13 fragment (Supplementary Movie 1). Circles indicate characteristic examples of (1) complete origami folding from initially adsorbed state (white), (2) complete origami folding in bulk prior to adsorption (blue), (3) adsorption of origamis followed by folding (yellow). b–d, Detailed evolution of the folding process of the three individual origamis indicated by white circles B (b), C (c) and D (d) in a evidencing three characteristic folding pathways from the initial Λ shape to the fully folded sharp triangle. Images are extracted from Supplementary Movies 2–4. e, Schematic diagram showing at least three folding pathways. [M13] = 1 nM; each staple concentration is 40 nM.