Lateral displacement and conformation of DNA chains in abrupt 90° microbends

The migration and conformation of a single λ-DNA chain in a microchannel with a 90 bend have been investigated using the hybrid numerical scheme of Brownian dynamics (BD) simulations and a CFD (computational fluid dynamics) solver, Flow-3D. A significant displacement of the single DNA chain was found after it had passed through the microbend and depended on its initial location. The λ-DNA chain initially positioned near the inner (or outer) wall migrated farther toward the inner (or outer) wall after passage through the bend. This is ascribed by the hydrodynamic features of the bulk flow field in the bend region. The relationship between an extension of the single chain and the flow characteristics was elucidated by changing the effective shear rate and the channel width.