Molecular motors: DNA gets a little cagey

Electronic control of DNA-based nanoswitches and nanodevices

Here we demonstrate that we can rationally and finely control the functionality of different DNA-based nanodevices and nanoswitches using electronic inputs. To demonstrate the versatility of our approach we have used here three different model DNA-based nanoswitches triggered by heavy metals and specific DNA sequences and a copper-responsive DNAzyme. To achieve electronic-induced control of these DNA-based nanodevices we have applied different voltage potentials at the surface of an electrode chip. The applied potential promotes an electron-transfer reaction that releases from the electrode surface a molecular input that ultimately triggers the DNA-based nanodevice. The use of electronic inputs as a way to finely activate DNA-based nanodevices appears particularly promising to expand the available toolbox in the field of DNA nanotechnology and to achieve a better hierarchical control of these platforms.

Rational design of pH-controlled DNA strand displacement

Achieving strategies to finely regulate with biological inputs the formation and functionality of DNA-based nanoarchitectures and nanomachines is essential toward a full realization of the potential of DNA nanotechnology. Here we demonstrate an unprecedented, rational approach to achieve control, through a simple change of the solution's pH, over an important class of DNA association-based reactions. To do so we took advantage of the pH dependence of parallel Hoogsteen interactions and rationally designed two triplex-based DNA strand displacement strategies that can be triggered and finely regulated at either basic or acidic pHs. Because pH change represents an important input both in healthy and pathological biological pathways, our findings can have implication for the development of DNA nanostructures whose assembly and functionality can be triggered in the presence of specific biological targets.

Reconfigurable DNA origami to generate quasifractal patterns

The specificity of Watson-Crick base pairing, unique mechanical properties of DNA, and intrinsic stability of DNA double helices makes DNA an ideal material for the construction of dynamic nanodevices. Rationally designed strand displacement reactions can be used to produce dynamic reconfiguration of DNA nanostructures postassembly. Here we describe a 'fold-release-fold' strategy of multiple strand displacement and hybridization reactions to reconfigure a simple DNA origami structure into a complex, quasifractal pattern, demonstrating a complex transformation of DNA nanoarchitectures.

Catch and release: DNA tweezers that can capture, hold, and release an object under control

A pair of DNA tweezers are constructed, which are capable of capturing, holding and releasing a DNA object by playing with the open and close actions of the tweezers assisted by pH switchings. The object is captured between the tweezers' arms at pH 5.0 through Hoogsteen hydrogen bonding and can be stably held even when the pH is increased to 5.7 after the tweezers are closed. Upon introducing a DNA unlocker strand, the tweezers are opened and the object gets released. This capture-hold-release process can be easily cycled without losing much of its efficiency.