It seems difficult to thread a potential target species through the cavity at the center of a DNA
nanotube. We present a solution to this problem by developing DNA half-tubes designed to
cover one side of a rod-like species. We have designed these half-tubes so that they can form
full nanotubes, thereby producing the complete cavity, and potentially sheathing its contents.
We have done this with two different species, a six-helix bundle (6HB) and an eight-helix
bundle (8HB). The six-helix tube is composed of two different bent triple-crossover (BTX)
molecules containing a 120° bend between their two DX components; the two BTX molecules
join face-to-face to produce the target species. The eight-helix bundle is built from a single
arched four-helix component (4HB) that joins with another copy of itself to produce the eighthelix
tube.