Particle sorting in a mini step-split-flow thin channel: influence of hydrodynamic shear on transversal migration.

A mini splitterless-split-flow thin fractionation (SPLITT) device has been developed to achieve fast separations of micrometer-sized species. In this device, inlet and outlet steps have replaced the splitters, which are common to conventional SPLITT channels. By elimination of the splitters, it becomes straightforward to reduce channel dimensions while maintaining the classic method of fabrication. Reduced dimension channels allow high axial velocity at relatively low flow rate. These high axial velocities generate an enhancement of inertial lift forces and hydrodynamic shear-induced diffusion. Experiments carried out with particulate and biological species in a mini step-SPLITT channel demonstrate that these hydrodynamic effects yield highly enriched fractions of smaller species from binary mixtures.