Construction of One- and Two-Dimensional Nanostructures by the Sequential Assembly of Quadruplex DNA Scaffolds.

A quadruplex-integrated assembly method is proposed for the organization and regulation of various nanoscale architectures. In this method, two types of one-dimensional DNA nanostructures formed by two well-designed GC-rich single strands assemble into two-dimensional (2D) DNA nanostructures based on the self-assembly of dimeric G-quadruplex and I-motif structures. Subsequently, a C-rich strand and two biotin-modified G-rich strands primordially form a notched double helix in LiCl solution (pH 8). However, a linear "DNA-protein" nanostructure linked by I-motif structures and biotin-streptavidin interaction can be formed when hydrogen ions and streptavidin are sequentially titrated. Furthermore, the linear "DNA-protein" nanostructure is assembled into 2D nanomaterials connected by K+-stabilized G-quadruplexes formed from terminal G-rich repeats of the two G-rich strands. Interestingly, the 2D nanohybrids form two-lined "DNA-protein" nanostructures if the terminal G-rich repeats in one of the biotin-modified G-rich strands are removed. Our results indicate that quadruplex DNAs are promising building blocks in the fabrication of nanomaterials and that the assembly of quadruplex DNAs has potential applications in the directional arrangement of macromolecules.