(676e) Tuneable Mechanical Response of Twisted DNA Nanotubes Towards Biosensing

Helical motifs can be found abundantly in the biological world of micro- and nanostructures such as microbial flagella and cellulose fibrils. As engineering components, helical motifs exist in the macroscopic world as screws and springs. Downsizing these simple tools into the micron scale would help towards understanding mechanical forces and motion that regulate the function of numerous mechanosensory systems. Examples of these systems include motor proteins and cytoskeletal filaments. Multi-helical DNA bundles could serve as a model nanomaterial to build nanoarchitectures that could sense or mimic such biological molecules and systems.

We focus here on the reversible conformational change of tuneable twist features on DNA nanotubes. The DNA nanotubes are self-assembled into their pre-stressed twisted state through specific and localized basepair insertions on select DNA single-stranded tiles (SST). Using microscopic techniques including TEM and TIRF microscopy, we show that that these twisted DNA nanotubes can reversibly twist and untwist via toe-hold mediated strand displacement of incoming fuel DNA strands. Our results also show the capability of these systems to undergo reversible twisting when substrate- or interface-bound. These results highlight the capability of these twisted DNA nanotubes to be used as mechanical biosensors in biological systems and tuneable microswimmers in biomimetic applications.