Connecting magnetic micro-particles with DNA G-quadruplexes

Abstract

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”.