Patent ID: 9702806
Date: 2017-07-11
CPC Classifications: G01N

Claim:
1. A method for imaging a plurality of particles using a particle analysis system configured for combined viscosity and geometric hydrofocusing, the particles included in a blood fluid sample having a sample fluid viscosity, the method comprising: flowing a sheath fluid along a flowpath of a flowcell, the sheath fluid having a sheath fluid viscosity that differs from the sample fluid viscosity by a viscosity difference in a predetermined viscosity difference range; injecting the blood fluid sample into the flowing sheath fluid within the flowcell so as to provide a sample fluid stream enveloped by the sheath fluid; flowing the sample fluid stream and the sheath fluid through a reduction in flowpath size toward an imaging site, such that a viscosity hydrofocusing effect induced by an interaction between the sheath fluid and the sample fluid stream associated with the viscosity difference, in combination with a geometric hydrofocusing effect induced by an interaction between the sheath fluid and the sample fluid stream associated with the reduction in flowpath size, is effective to provide a target imaging state in at least some of the plurality of particles at the imaging site while a viscosity agent in the sheath fluid retains viability of cells in the sample fluid stream leaving structure and content of the cells intact when the cells extend from the sample fluid stream into the flowing sheath fluid; and imaging the plurality of particles at the imaging site, wherein the plurality of particles are a plurality of cells, wherein associated with the injecting step the plurality of cells include a first subset with major surfaces oriented transverse to an orientation of an imaging path, wherein the imaging step comprises imaging the plurality of cells along the imaging path at the imaging site while the plurality of cells include a second subset with the major surfaces oriented transverse to the imaging path, the second subset being more numerous than the first subset, and wherein the interaction between the sheath fluid and the blood fluid sample associated with the differing viscosities reorients at least some of the plurality of cells such that the second subset is more numerous than the first subset.