Transient DNA-based nanostructures controlled by redox inputs

Synthetic DNA has emerged as a powerful selfassembled material for the engineering of nanoscale supramolecular devices and materials. Initial examples were focused on thermodynamically driven self-assembly of DNA-based structures with exquisite near-angstrom control of their geometry. More recently dissipative self-assembly of DNA-based supramolecular structures has emerged as a novel approach providing access to a new class of kinetically-controlled DNA materials with unprecedented life-like properties. In the examples reported so far, dissipative control has been achieved using DNA-recognizing enzymes as energy dissipating units. Although highly efficient, enzymes pose limits in terms of long term stability and inhibition of enzyme activity by waste products. Here we provide the first example of kinetically controlled DNA nanostructures in which energy dissipation is achieved through a non-enzymatic chemical reaction. More specifically, inspired by the redox signalling employed by cells to control cellular processes, we employ redox cycles of disulfide-bond formation/breakage to kinetically control the assembly and disassembly of DNA tubular nanostructures in a highly controllable and reversible fashion. To this purpose, we have rationally designed disulfide DNA strands acting as regulators for the assembly or disassembly of the DNA-based structures. Upon reduction these strands loose their regulatory function which causes the system to return to the basal nonassembled resting state. The exploitation of redox chemistry as a new control mechanism will facilitate the implementation of fuelledDNA self-assembly processes in a synthetic context without the limitations linked to the use of enzymatic reactions.