Methods and systems for processing particles

A system for processing first particles from a sample, the first particles comprising leukocytes or stem cells, the system comprising:

• a) a microfluidic device, wherein the microfluidic device comprises:
• i) a fluidic channel extending from a plurality of inlets to a plurality of outlets;
• ii) a first array of obstacles arranged in rows in the channel, wherein each subsequent row of obstacles is shifted laterally with respect to a previous row, wherein the array of obstacles is configured to differentially deflect first particles of at least a predetermined size to a first outlet and second particles of less than the predetermined size to a second outlet, and wherein:
• aa) surfaces of two adjacent obstacles in a row of the array of obstacles define a gap;
• bb) the two adjacent obstacles defining the gap each have a polygonal cross-section, wherein the polygonal cross-section is disposed within the fluidic channel;
• b) a flow through incubator comprising a first inlet configured to receive separated particles from the first outlet of the microfluidic device, a second inlet fluidically connected to a liquid source comprising a reagent, a serpentine channel, and at least one outlet, and
• c) a balancer that is fluidically connected to the second outlet of the microfluidic device such that a liquid exiting from the second outlet of the microfluidic device directly flows into the balancer, wherein the balancer is configured to have a fluidic resistance that is substantially the same as a fluidic resistance through the flow-through incubator,
• wherein the balancer comprises a fluidic pressure control comprising a second serpentine channel, and
• the fluidic pressure control is capable of generating negative pressure in the balancer.