Systems and methods for particle focusing in microchannels

A device for focusing particles suspended within a fluid and analyzing the focused particles, the device comprising:

• (a) a substrate;
• (b) one or more focusing channels formed in the substrate, wherein each of the focusing channels spans a length from an inlet to an outlet and has a respective channel hydraulic diameter (Dh), wherein each of the focusing channels includes a plurality of curves, and wherein each of the focusing channels is arranged to allow a fluid having a kinematic viscosity (ν) and comprising suspended particles, each having a particle hydraulic diameter (a), to flow therethrough;
• and
• (c) one or more analysis channels formed in the substrate, wherein an inlet of each of the one or more analysis channels is in fluid communication with an outlet of a respective one of the one or more focusing channels;
• wherein the one or more focusing channels are dimensioned and configured such that when the fluid that includes the suspended particles is driven through the one or more focusing channels at a maximum channel velocity (Um) resulting in a laminar fluid flow and a particle Reynolds Number (Rp) of greater than or equal to 0.2, wherein the particle Reynolds number is defined as
• R
• p
• =
• U
• m
• ⁢
• a
• 2
• vD
• h
• ,
• the particles suspended in the fluid are focused to flow along one or more localized stream lines that form in the fluid at the outlet of each of the one or more focusing channels.