(142bk) Particle Dynamics and Scaling in Inertial Microfluidic Flows

Microfluidic inertial focusing has enabled the development of miniaturized flow cytometers, size-selective sorting devices and other high-throughput particle screening tools by reliably positioning particles to well-defined lateral and longitudinal locations.  The equilibrium positions of inertially focused particles has been extensively studied and the constitutive phenomena empirically characterized in straight channels of square and rectangular cross section.  In order to design higher throughput devices with a broader range of applications, a better understanding of particle dynamics during focusing is required.  This talk will focus on the elucidation of scaling relationships that determine relative equilibrium positions of various sized particles with different concentrations in channels of varying cross-sectional geometry, including non-traditional cross-sections.  We have investigated the competing inertial forces that contribute to lateral focusing and determine the threshold at which Stokes’ flow begins to influence lateral focusing.  Experiments to quantify the dynamics of lateral particle migration have been used to quantify the shear and wall-induced inertial lift forces, which is used to verify our scaling and also inform alternate designs for optimal focusing.  Finally, we demonstrate new high-throughput particle analysis applications that are enabled by an improved understanding of particle dynamics during inertial focusing.