Séminaire exceptionnel IUSTI – 25 oct. 2022 – 14h salle ???

Polyelectrolyte transport in microfluidic geometries using simultaneous flow and electrophoresis.

Jason Butler – Univ. Florida, ÉU

I describe a simple method to control the distribution and transport of polyelectrolytes, and DNA in particular, within microfluidic channels. The method uses parallel and anti-parallel flows and electric fields to either migrate DNA toward the channel walls or to focus DNA along the center-line. Hydrodynamic interactions caused by the electric field acting on the charged DNA in the presence of a shear flow are identified as the physical mechanism that drives the migration. This hypothesis contradicts the common assumption that electrophoresis generates no velocity disturbances and that the charged particles and polymers “slip” through the fluid in response to the electric field. However, comparing experimental results with theories and simulations validates the proposed mechanism. Furthermore, alternative hypotheses that might explain the migration are shown to be invalid or inapplicable.