In-Situ Configuration Studies on Segmented DNA Origami Nanotubes.

One-dimensional nanotubes are of considerable interest in materials and biochemical sciences. A particular desire is to create DNA nanotubes with user-defined structural features and biological relevance, which will facilitate the application of these nanotubes in the controlled release of drugs, templating of other materials into linear arrays and the construction of artificial membrane channels. However, little is known about the structures of assembled DNA nanotubes in solution. Here we report an in situ exploration of segmented DNA nanotubes, composed of multiple units with set length distributions, by using synchrotron small-angle X-ray scattering (SAXS). Through joint experimental and theoretical studies, we show that the SAXS data are highly informative in the context of heterogeneous mixtures of DNA nanotubes. The structural parameters obtained by SAXS are in good agreement with those determined by atomic force microscopy (AFM), transmission electron microscopy (TEM), and dynamic light scattering (DLS). In particular, the SAXS data revealed important structural information on these DNA nanotubes, such as the in-solution diameters (≈25 nm), which could be obtained only with difficulty by use of other methods. Our results establish SAXS as a reliable structural analysis method for long DNA nanotubes and could assist in the rational design of these structures.