Particle self-assembly using DNA has relied mainly on the interaction between complementary strands of double helix DNA. In contrast, G-quadruplex DNA has rarely been used in particle self-assembly.G-quadruplex DNA can adopt a wide range of structures with diverse topologies and stabilities controlled by cations. We report on the possibility of connecting micrometer-sized magnetic beads using DNA G-quadruplexes under a magnetic field. The average chain length of the resulting fragments was used to quantify the strength of the interaction, which was shown to depend on the nature and concentration of cations, the DNA sequences, the time duration and strength of the applied magnetic field. Through the use of different sequences, we propose that the length of bead chains could be quantitatively associated with the stability and structure of DNA G-quadruplexes formed between the beads. This work may allow us to control the interactions in colloidal assembly architectures using G-quadruplexes and also to study the structure, dynamics and other properties of the G-quadruplex "DNA glue".

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Single phase W18O49 sintered polycrystalline samples were successfully synthesized via one-step rapid reactive spark plasma sintering directly from commercially purchased WO3 and WO2 powders. Thermoelectric properties of the samples sintered at 15 and 30 MPa showed insignificant anisotropy, while a strong anisotropy was observed for the sample sintered at 50 MPa. The in-situ reaction under a high applied pressure allowed a preferential grain growth along the direction perpendicular to the pressure axis. The high anisotropy of the sample sintered at 50 MPa yielded the lowest thermal conductivity of 4 Wm −1 K −1 , resulting in a ZT value of 0.08 at 1073 K. This study offers the rapid and cost-effective preparation method for W18O49 materials, which can also be applied for other tungsten suboxide phases, with partially controlled anisotropic properties by the influence of applied pressure for thermoelectric performance enhancement.