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Free keywords:
SUPERRESOLUTION MICROSCOPY; FOLDING DNA; NANOROBOT; DEVICES; SHAPES;
GOLDChemistry; Science & Technology - Other Topics; Materials Science;
Physics; DNA origami nanostructures; DNA-PAINT; entropic force; nanoparticles;
single-stranded DNA; super-resolution microscopy;
Abstract:
The design of dynamic, reconfigurable devices is crucial for the bottom-up construction of artificial biological systems. DNA can be used as an engineering material for the de-novo design of such dynamic devices. A self-assembled DNA origami switch is presented that uses the transition from double- to single-stranded DNA and vice versa to create and annihilate an entropic force that drives a reversible conformational change inside the switch. It is distinctively demonstrated that a DNA single-strand that is extended with 0.34 nm per nucleotide - the extension this very strand has in the double-stranded configuration - exerts a contractive force on its ends leading to large-scale motion. The operation of this type of switch is demonstrated via transmission electron microscopy, DNA-PAINT super-resolution microscopy and darkfield microscopy. The work illustrates the intricate and sometimes counter-intuitive forces that act in nanoscale physical systems that operate in fluids.