Patent ID: 8186913

Claim:
A system for focusing particles suspended within a moving fluid, the system comprising: a substrate; at least one channel provided on the substrate, the at least one channel having an inlet, an outlet, a plurality of sides, wherein the relative geometry of the sides defines an aspect ratio, and a channel hydraulic diameter (D h ), wherein the at least one channel is configured to allow a fluid having a substantially constant kinematic viscosity (v) that includes suspended particles, each having a particle diameter (a), to flow therethrough; and a pumping element designed to drive the fluid that includes the suspended particles through the at least one channel; wherein when the fluid that includes the suspended particles is flowed through the at least one channel, and the pumping element drives the fluid that includes the suspended particles at a maximum channel velocity (U m ) resulting in a laminar fluid flow and a particle Reynolds Number (R p )) of greater than or equal to 0.2, wherein the particle Reynolds number is defined as R p = U m ⁢ a 2 ⁢ vD h , one or more localized stream lines are formed in the fluid, wherein each localized stream line defines a width that is substantially equal to or greater than a size of the focused particles, and the particles suspended in the fluid are focused into the one or more localized stream lines, wherein the number and relative cross-sectional position of the one or more localized stream lines are uniquely defined by the aspect ratio and the particle Reynolds number.