Fig. 1.

Schematics of the experimental flow setups used in the present study. (a) A cone-plate viscometer was used to measure the suspension viscosities of neutrophil populations under a uniform shear field. Activated neutrophils with extended pseudopods, in contrast to inactivated neutrophils, were anticipated to increase viscosity due to enhanced numbers of stochastic cell–cell interactions resulting from increased cell tumbling. (b) For flow studies, cells were perfused through three different experimental chambers designed to test the impact of neutrophil pseudopod activity on rheological flow properties. These chambers included (1) an isopore membrane with pore sizes of 10 μm to simulate microcapillary flow; (2) a single-channel microchamber (w: 500 μm; h: 50 μm; and l: 20 mm) to simulate flow through the large microvessels; and (3) a network of twenty 20 × 50 μm microfluidics channels to simulate flow through noncapillary microvasculature. Pressure changes were recorded with a strain gauge pressure transducer and analyzed in labview signals express.