Self-Assembled DNA Tubes Forming Helices of Controlled Diameter and Chirality.

Multihelical DNA bundles could enhance the functionality of nanomaterials and serve as model architectures to mimic protein filaments on the molecular and cellular level. We report the self-assembly of micrometer-sized helical DNA nanotubes with widely controllable helical diameters ranging from tens of nanometers to a few micrometers. Nanoscale helical shapes of DNA tile tubes (4-, 6-, 8-, 10-, and 12-helix tile tubes) are achieved by introducing discrete amounts of bending and twist through base pair insertions and/or deletions. Microscale helical diameters, which require smaller amounts of twist and bending, are achieved by controlling the intrinsic "supertwist" present in tile tubes with uneven number of helices (11-, 13-, and 15-helix tile tubes). Supertwist fine-tuning also allows us to produce helical nanotubes of defined chirality.