An engineered DNA crystal actuator system

(Nanowerk News) The design of macroscopic material with desired chemical, physical, and mechanical properties from the molecular level up is an ongoing challenge for self-assembly and nanotechnology.
Due to its unparalleled programmability and biocompatibility, structural DNA nanotechnology has proved to be a potent approach to such designs, where the self-assembled nanostructures are responsive via a variety of mechanisms including DNA strand displacement, conformation change of specific motifs, targeting with DNA aptamers (see for instance: "Cancer-fighting nanorobots programmed to seek and destroy tumors"), and DNAzyme domains.
Whereas these approaches promise great potential for sensitive biosensing, controllable drug delivery, medical diagnosis, and disease treatment, most reconfigurations of the self-assembled nanostructures are limited to the scale of nanometers.
Now, in new work reported in Advanced Materials ("Powering ≈50 µm Motion by a Molecular Event in DNA Crystals"), researchers demonstrate an engineered DNA crystal actuator system that can reversibly expand and contract over 50 µm in response to multiple external stimuli.
During this expansion/contraction process, the porosity (thus the permeability) of the crystal greatly changes, which provides a mechanism to reversibly encapsulate/release nanoparticles or proteins.
Schematic design of stimuli-responsive DNA crystals
Schematic design of stimuli-responsive DNA crystals. a) The DNA tensegrity triangle motif. b) The self-assembled crystal of DNA triangles. The solid pink circles labeled with P represent 5′-phosphates. c) 2D ligated DNA crystals. Note that DNA frameworks are held along horizontal direction by sticky-end cohesion (red). d) DNA crystal expansion responds to external stimuli. e) An overall view of the expansion/contraction of DNA crystals. (Reprinted with permission by Wiley-VCH Verlag)
The authors of the study envision that their work will lead to several exciting possibilities as smart materials, including: 1) the easily observable size change of DNA crystals could be exploited as a report for chemical detection; and 2) the system can serve as a sponge to store and release nanometer-sized particles and to delivery macromolecular drugs (e.g., small nucleic acids and proteins).
By Michael is author of three books by the Royal Society of Chemistry:
Nano-Society: Pushing the Boundaries of Technology,
Nanotechnology: The Future is Tiny, and
Nanoengineering: The Skills and Tools Making Technology Invisible
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