Long, Monomolecular Guanine-Based Nanowires

摘要

Guanine (G) tetrads have been proposed as building blocks for molecular nanowires for nanoelectronics. Such wires utilize the spontaneous assembly of guanine-rich DNA sequences and form, in the presence of properly chosen cations, tetrads that are further arranged in a tetra-helical structure, as shown schematically in Figure 1. All previously reported G-wires are constructed of short oligomers. resulting in non-uniform polymers having gaps (non-covalently bonded backbone) between the oligonucleotide fragments along the formed wires. Here, we report the synthesis and characterization of continuous, monomolecular G-wires, presumably G4-DNA, made of guanine tetrads, composed of single, self-folded poly(G) strands of thousands of bases. The cation-independent wires are characterized using gel electrophoresis (Fig. 2a), UV spectroscopy (Fig. 2b), circular dichroism (CD) spectroscopy (Fig. 2c), and atomic force microscopy (AFM, Figs. 3,4) and are shown to be long, stiff, practically heat-resistant, mechanically stable, and insensitive to deoxyribonuc-lease I (DNase) degradation. Their properties make them attractive candidates for applications in nanoelectronics.