Joining and scission in the self-assembly of nanotubes from DNA tiles.

We present the first direct observations of tile-based DNA self-assembly in solution using fluorescent nanotubes composed of a single tile. The nanotubes reach tens of microns in length by end-to-end joining rather than by sequential addition of single tiles. Their exponential length distributions withstand dilution but decay via scission upon heating, with an energy barrier Esc approximately 180kBT. DNA nanotubes are thus uniquely accessible equilibrium polymers that enable new approaches to optimizing DNA-based programming and understanding the biologically programmed self-assembly of protein polymers.