Deterministic Lateral Displacement In Anisotropic Media for Particle Separations In Microfluidic Devices

Earlier, we directly measured the Brownian diffusion of the particles in the absense of external field in an anisotropic periodic array of rectangular obstacles and showed that the particle-wall hydrodynamic interactions lead to non-linear effects in the mobility of differently sized particles.  We suggested the possibility of using such anisotropic media for the continuous separation of particles in the presence of an external field.  Here, we use gravity to drive the particles and introduce a forcing angle in the media different from the direction of gravity.  We explore non-linear relations between force and velocity in such systems and establish the deterministic lateral displacements leading to particle separation.