DNA-Mediated Stabilization of Self-Assembling Bead Monolayers for Microfluidic Applications

Forming ordered 2D or 3D arrays of colloidal particles on the micro‐ or nanometer scale in a bottom‐up process is a challenging task. In previous works by various groups, hybridization between DNA strands localized on the particle surface is used to create crystalline arrays. However, this method requires an annealing process with a duration of one day or more and usually yields agglomerates of only a few dozen particles. In this work, a method for the rapid formation of highly‐ordered 2D agglomerates of superparamagnetic microparticles (beads) is presented. Dipolar coupling between the beads under the influence of a rotating magnetic field leads to the formation of a dense monolayer. The monolayer is then stabilized through DNA hybridization between DNA strands immobilized on the bead surface and a linker strand in solution. The whole self‐assembly process requires less than an hour and is therefore significantly faster than comparable methods. Methods to obtain ordered arrangements of micro‐ or nanoparticles from a bottom‐up assembly process by DNA hybridization between single‐stranded DNA grafted to the particles require annealing times of one day or more. Here, a self‐assembly process using dipolar coupling between functionalized, superparamagnetic microparticles is used to create DNA‐stabilized 2D aggregates in less than an hour.